ARTICLE Download: 47| View: 58| Comments: 0 | doi:10.20944/preprints202001.0061.v1
Subject: Engineering, Civil Engineering Keywords: coastal seawall; impermeable; bimodal seas; reflection coefficient; bimodality; wave steepness; swell percentages
Online: 8 January 2020 (04:24:42 CET)
Understanding of reflection characteristics of coastal seawalls is crucial for design. Wave reflection can cause difficulties to small vessel manoeuvring at the harbour entrance and constitute damaging scouring at the toe of coastal structures. Previous studies have considered reflection characteristics of coastal seawalls under wind-generated random waves without paying attention to the effects of wave bimodality created by the presence of swell waves. The present study focuses on the influence of random wave bimodality on reflective characteristics of coastal seawalls. More than eight hundred experimental tests have been conducted to examine the reflection performance of impermeable sloping seawalls under bimodal waves. Reflection coefficients were computed from each test. Analysis of results suggests that both unimodal and bimodal waves give similar reflection characteristics. However, the reflection coefficient in bimodal sea states seems to be more prolonged than in the unimodal sea states. It was found that the reflection coefficient of coastal seawalls is strongly influenced by the seawall slope, the wave steepness, relative water depth, and the surf similarity parameters. A new empirical reflection equation to describe the influence of wave bimodality on the reflection characteristics of coastal seawalls has been formulated based on this study.
ARTICLE Download: 112| View: 192| Comments: 0 | doi:10.20944/preprints202001.0060.v1
Subject: Engineering, Electrical & Electronic Engineering Keywords: indoor location; fine time measurement; round trip time; FTM; RTT; IEEE 802.11mc; IEEE 802.11-2016; time diversity; spatial diversity; bandwidth diversity; frequency diversity; Bayesian grid; observation model; transition model
Online: 8 January 2020 (04:18:02 CET)
Determination of indoor location based on fine time measurement (FTM) of the round trip time (RTT) of a signal between an initiator (smartphone) and a responder (Wi-Fi access point) enables a number of applications. However, the accuracy currently attainable — standard deviations of 1–2 meter in distance measurement under favorable circumstances — limits the range of possible application. A first responder, for example, may not be able to unequivocally determine on which floor someone in need of help is in a multi-story building. The error in location depends on several factors, including the bandwidth of the RF signal, delay of the signal due to the high relative permittivity of construction materials, and the geometry-dependent “noise gain” of location determination. Errors in distance measurements have unusual properties that are exposed here for the first time. Improvements in accuracy depend on understanding all of these error sources. This paper introduces “frequency diversity,” a method for doubling the accuracy of indoor location determination using weighted averages of measurements with uncorrelated errors obtained in different channels. The properties of this method are verified experimentally with a range of responders. Finally, different ways of using the distance measurements to determine indoor location are discussed and the Bayesian grid update method shown to be more useful than others, given the non- Gaussian nature of the measurement errors.
ARTICLE Download: 37| View: 48| Comments: 0 | doi:10.20944/preprints202001.0058.v1
Subject: Engineering, Civil Engineering Keywords: slate; random fill; compaction quality control; wheel-tracking test; topographic settlement
Online: 8 January 2020 (03:23:13 CET)
Particle size can pose a challenge to random embankment compaction control methods, where practical techniques have hardly been developed and procedural control is used instead. In order to develop new quality control procedures for slate random fill, the necessary fieldwork and laboratory tests were carried out. This involved the revision of certain methods such as the wheel-tracking or topographic settlement tests. More than four thousand five hundred in-situ density and moisture content measurements were carried out for this research. In addition, more than five hundred and eighty topographic settlements and nine hundred and sixty wheel-tracking carriage tests were performed. The quality control processes were completed with more than one hundred and thirty plate bearing tests. Possible evidence of statistical correlations between compaction control tests were identified. An analysis of variance (ANOVA) was performed. When testing proved relationships between them, the replacement of one of them by the other was assessed by deduction. Finally, the study suggests new procedures for compaction quality control of random slate fill used in core area.
Tue, 7 January 2020
ARTICLE Download: 45| View: 52| Comments: 0 | doi:10.20944/preprints202001.0055.v1
Subject: Engineering, Electrical & Electronic Engineering Keywords: microphone array; wave field synthesis; acoustic holography; sampler; synthesizer
Online: 7 January 2020 (10:27:54 CET)
To date electric pianos and samplers tend to concentrate on authenticity in terms of temporal and spectral aspects of sound. They barely recreate the original sound radiation characteristics, contribute to the perception of width and depth, vividness and voice separation, especially for instrumentalists, who are located in the near field. This paper describes an operational procedure to measure, store, and synthesize the complete sound of a harpsichord, including its spatial sound radiation characteristics. First, actuators excite the instrument at the intersection point of each string with the bridge with an exponential sine-sweep. Then, the radiated sound field is recorded in the near and the far field with microphone arrays. The pressure distribution in the near field is propagated back to the soundboard of the instrument, using Minimum Energy Method. The vibration of each single string is captured with lightweight contact microphones. The soundboard is then replaced by an array of 128 loudspeakers. The loudspeaker signal is a convolution of the back-propagated sweep recording with the string recording to perform a wave field synthesis. Above the spatial Nyquist frequency, the Radiation Method is applied to perform a sound field synthesis which is valid for the listening region of the instrumentalist. The result is an electric harpsichord, that approximates the sound of a real harpsichord precisely in time, frequency, and space domain. Applications for such a radiation keyboard are music performance, instrument and synthesizer building and interactive psychoacoustic research.
ARTICLE Download: 72| View: 70| Comments: 0 | doi:10.20944/preprints202001.0054.v1
Subject: Engineering, Energy & Fuel Technology Keywords: lithium-ion (Li-ion) battery; remaining useful life (RUL); health indicator (HI); generalized regression neural network (GRNN); non-linear autoregressive (NAR)
Online: 7 January 2020 (09:17:28 CET)
The remaining capacity can only be measured with offline method. This brings great challenge for the online prediction of Li-ion battery’s RUL. A novel online prediction method for Li-ion battery’s RUL was proposed, which is based on multiple health indicators (HIs) and can be derived from the batteries’ historical operation data. Firstly, four indirect HIs were built according to the battery’s operation current, voltage and temperature data respectively. On that basis, a generalized regression neural network (GRNN) was developed to estimate the battery’s remaining capacity, and the non-linear autoregressive approach (NAR) was utilized to predict the battery’s RUL based on the estimated capacity value. Furthermore, to reduce the interference, twice wavelet denoising were performed with different thresholds. A case study is conducted with a NASA battery dataset to demonstrate the effectiveness of the method. The result shows that the proposed method can obtain Li-ion batteries’ RUL effectively.
ARTICLE Download: 42| View: 47| Comments: 0 | doi:10.20944/preprints202001.0053.v1
Subject: Engineering, Electrical & Electronic Engineering Keywords: antenna; PIFA; LTE; 5G; communication
Online: 7 January 2020 (04:17:21 CET)
This paper designed a miniaturized Planer Inverted-F Antenna for 5G communication networks including Long Term Evolution Advanced mobile communication services. With showing the radiation pattern, voltage standing wave ratio, and antenna gain of the designed Planer Inverted-F Antenna, this paper evaluates its performance. To show the key characteristics of the Planer Inverted-F Antenna, this paper modeled and simulated it with various variances. Moreover, the real Planer Inverted-F Antenna is fabricated, and measurements were done to validate the simulated characteristics of the internal antenna.
Sat, 4 January 2020
ARTICLE Download: 60| View: 92| Comments: 0 | doi:10.20944/preprints202001.0033.v1
Subject: Engineering, Electrical & Electronic Engineering Keywords: Smart Home (SH); Prediction; Artificial Neural Network (ANN); Fiber Bragg Grating (FBG); occupancy; number of person recognition; Scaled Conjugate Gradient (SCG)
Online: 4 January 2020 (08:32:18 CET)
This article introduces a new way of using a Fibre Bragg Grating (FBG) sensor for detecting the presence and number of occupants in the monitored space in a Smart Home (SH). CO2 sensors are used to determine the CO2 concentration of the monitored rooms in an SH. CO2 sensors can also be used for occupancy recognition of the monitored spaces in SH. To determine the presence of occupants in the monitored rooms of the SH, the newly devised method of CO2 prediction, by means of an Artificial Neural Network (ANN) with a Scaled Conjugate Gradient (SCG) algorithm using measurements of typical operational technical quantities (indoor temperature, relative humidity indoor and CO2 concentration in the SH) is used. The goal of the experiments is to verify the possibility of using the FBG sensor in order to unambiguously detect the number of occupants in the selected room (R104) and, at the same time, to harness the newly proposed method of CO2 prediction with ANN SCG for recognition of the SH occupancy status and the SH spatial location (rooms R104, R203, and R204) of an occupant. The designed experiments will verify the possibility of using a minimum number of sensors for measuring the non-electric quantities of indoor temperature and indoor relative humidity and the possibility of monitoring the presence of occupants in the SH using CO2 prediction by means of the ANN SCG method with ANN learning for the data obtained from only one room (R203). The prediction accuracy exceeded 90% in certain experiments. The uniqueness and innovativeness of the described solution lie in the integrated multidisciplinary application of technological procedures (the BACnet technology control SH, FBG sensors) and mathematical methods (ANN prediction with SCG algorithm, the Adaptive Filtration with of LMS algorithm) employed for the recognition of number persons and occupancy recognition of selected monitored rooms of SH.
REVIEW Download: 68| View: 71| Comments: 0 | doi:10.20944/preprints202001.0031.v1
Subject: Engineering, Mechanical Engineering Keywords: drag reduction; drag reducing agents; curved pipes; single phase flow; two phase flows
Online: 4 January 2020 (06:24:32 CET)
A review of influence of drag-reducing agents on curved pipe flows is presented in this work. In addition, this review outlined proposed mechanism, friction factor and fluid flux models for drag-reducing agents in curved pipe flows. Our finding reveals that drag reduction by additives in curved pipes is quite significant but generally lower than the corresponding drag reduction in straight pipes. It decreases with increase in curvature ratio and more pronounced in the transition and turbulent flow regimes. Drag reduction strongly depends on the polymers and surfactants’ concentrations as well as the bubble fraction of micro-bubbles. It is also reported that drag reduction in curved pipes depends on temperature and existence of dissolved salts in the fluids. Maximum drag reduction asymptote differed between straight and curved pipes and between polymer and surfactant. No definite conclusion could be drawn as regards drag reduction for two-phase flow in curved pipes due to the limited studies in this area. Many questions such as the mechanism of drag reduction in curved pipes and how drag-reducing agents interact with secondary flows still remained unanswered. Hence, some research gaps have been identified with recommendations for areas of future researches.
Fri, 3 January 2020
ARTICLE Download: 67| View: 70| Comments: 0 | doi:10.20944/preprints202001.0022.v1
Subject: Engineering, Civil Engineering Keywords: Leadership in Energy and Environmental Design; LEED; sustainable construction cost; Iran
Online: 3 January 2020 (04:42:10 CET)
Buildings use 30-40 % of all energy resources and are thus their main consumers in modern society. Moreover, buildings require a vast amount of different raw materials. During the last two decades, several green building certifications have been created in order to consider social, economic and environmental aspects of sustainability of buildings. One of the most famous and widely used of these certifications is Leadership in Energy and Environmental Design (LEED). So far, the use of LEED has concentrated in the US and other developed countries. One reason that restricts the use of this point-based system certification in developing countries is the limited data about its costs. In this study, the extra cost of the certification process will be evaluated besides the changes needed in the design of the building to reach the points required by LEED. At the first stage, the number of points the case study earns in its current format (Scenario 1) were found out, then the cost difference of getting either the Certified (Scenario 2) or Silver (Scenario 3) level LEED certification for the building was studied. It was found that besides some technical considerations, filling the criteria of the Certified and Silver level increases the total costs of construction by 3.4% and 5.9%. Further improvement of the building’s energy efficiency would enable the attainment of a higher-level certification. The results of the study could help to promote the use of green building certifications in Western Asia.
ARTICLE Download: 83| View: 90| Comments: 0 | doi:10.20944/preprints202001.0021.v1
Subject: Engineering, Biomedical & Chemical Engineering Keywords: cerebral palsy; robot assisted therapy; EMG; kinematic
Online: 3 January 2020 (02:38:16 CET)
Aim: To develop an index for quantitative assessment of the upper limb motor function in children with cerebral palsy before and after robot-assisted therapy. Method: An upper limb motor function index was developed using kinematic, surface electromyography and three-axis inertial measurements unit data collected from 15 children with cerebral palsy (CP) and 15 typically developed children. Children with CP underwent 18 robot-assisted therapy sessions with the REAplan device. All children were evaluated, using kinematic data from the REAplan, electromyography and three-axis inertial measurements unit readings from its accelerometer. A principal component analysis was conducted to produce an evaluation index, which is able to detect the deviation from the upper limb motor function of typically developing children group. Children with CP were evaluated twice before and after the intervention with Box and Blocks test and Finger-To-Nose test. The discriminative and concurrent validity of the upper limb motor function index were investigated. Results: The upper limb motor function index was higher in children with CP post therapy (p<0.001). Finger-To-Nose test values improved after robot-assisted therapy (p<0.03). A weak but positive correlation was observed between upper limb motor function index and clinical tests (r=0.012, p=0.95 and r=0.13, p= 0.54 for Box and Blocks test and Finger-To-Nose test respectively). Interpretation: The upper limb motor function index successfully differentiated between the typically developing children and children with CP and was effective in assessing the improvement of the upper limb motor function after robot-assisted therapy. The upper limb motor function index could be extended to assess and monitor rehabilitation therapies of other populations, such as those with stroke and Parkinson’s disease.
Thu, 2 January 2020
ARTICLE Download: 210| View: 375| Comments: 0 | doi:10.20944/preprints202001.0018.v1
Subject: Engineering, Energy & Fuel Technology Keywords: photovoltaic; EV; PHV; standardization; car-roof; flexible PV; performance modeling; rating
Online: 2 January 2020 (15:00:06 CET)
The energy yield of the Vehicle-integrated photovoltaic (VIPV) differs from that of the standard photovoltaics (PV). It is mainly by the difference of the solar irradiance onto the car-roof and car-bodies as well as its curved-shape. Both meaningful and practical modeling and measurement of the solar irradiance for VIPV are needed to be newly established, not the extension of the current technologies. The solar irradiance was modeled by a random distribution of the shading objects and car-orientation with the correction of the curved surface of the PV modules. The measurement of the solar irradiance onto the car-roof and car-body was done using five pyranometers in five local axes on the car for one year. The measured dynamic solar irradiance onto the car-body and car-roof was used for validation of the solar irradiance model in the car.
REVIEW Download: 61| View: 73| Comments: 0 | doi:10.20944/preprints202001.0017.v1
Subject: Engineering, Control & Systems Engineering Keywords: Cooperative Intelligent Transport Systems (CITS); Vehicle to Pedestrian (V2P); Vulnerable 15 Road Users (VRU); GPS; smartphones; Inertial Measurement Units sensors
Online: 2 January 2020 (14:40:11 CET)
The field of Cooperative Intelligent Transport Systems and more specifically Pedestrians to Vehicles (P2V) could be characterized as quite challenging, since there is broad research area to be studied, with direct positive results to society.P2V is a type of Cooperative Intelligent Transport System, within the group of Early Warning Collision/Safety System. In this article, we examine the research and applications carried out so far within the field of Pedestrians to Vehicles Cooperative Transport Systems by leveraging the information coming from VRU’s smartphones. Moreover, extensive literature review has been carried out in the fields of VRUs Outdoor Localisation via smartphones and VRUs Next Step/Movement Prediction, that are closely related to P2V applications and research. We identify gaps that exist in these fields that could be improved/extended/enhanced or newly developed, while we address the future research objectives and methodologies that could support the improvement/development of those gaps. We also propose a P2V security framework that combines prediction and communication capabilities in order to avoid accidents between pedestrians and vehicles.
ARTICLE Download: 73| View: 66| Comments: 0 | doi:10.20944/preprints202001.0013.v1
Subject: Engineering, Electrical & Electronic Engineering Keywords: microgrids; prosumers; local trading; peer-to-peer contracts; blockchain technology
Online: 2 January 2020 (04:56:11 CET)
A growing number of households benefit from the government subsidies to install renewable generation facilities such as PV panels, used to gain independence from the grid and provide cheap energy. In the Romanian electricity market, these prosumers can sell their generation surplus only at regulated prices, back to the grid. A way to increase the number of prosumers is to allow them to make higher profit by selling this surplus back into the local network. This would also be an advantage for the consumers, who could pay less for electricity exempt from network tariffs and benefitting from lower prices resulting from the competition between prosumers. One way of enabling this type of trade is to use peer-to-peer contracts traded in local markets, run at microgrid (μG) level. This paper presents a new trading platform based on smart peer-to-peer (P2P) contracts for prosumers energy surplus trading in a real local microgrid. Several trading scenarios are proposed, which give the possibility to perform trading based on participants’ locations, instantaneous active power demand, maximum daily energy demand and the principle of first come first served implemented in an anonymous blockchain trading ledger. The developed scheme is tested on a low-voltage (LV) microgrid model to check its feasibility of deployment in a real network. A comparative analysis between the proposed scenarios, regarding traded quatities and financial benefits is performed.
Tue, 31 December 2019
ARTICLE Download: 77| View: 70| Comments: 0 | doi:10.20944/preprints201912.0417.v1
Subject: Engineering, Mechanical Engineering Keywords: tangible interfaces; Internet of Things tangibles; children with hearing impairment
Online: 31 December 2019 (16:48:04 CET)
A Tangible User Interface (TUI) is a new interaction option that uses nontraditional input and output elements. A tangible interface thus allows the manipulation of physical objects using digital information. The exploration and manipulation of physical objects is a factor to be considered in learning in children, especially those with some kind of disability such as hearing, who maximize the use of other senses such as vision and touch. In a tangible interface, three elements are related - physical, digital and social. The potential of IoT for children is growing. This technology IoT integrated with TUI, can help for that parents or teachers can monitoring activities of the child. Also to identify behavior patterns in the child with hearing impairment. This article shows four case studies, where had been designed different products of Internet of Things Tangible applied a several contexts and with products of low cost.
ARTICLE Download: 41| View: 101| Comments: 0
Subject: Engineering, Electrical & Electronic Engineering Keywords: piezoelectric materials; piezoelement; 1-3 piezocomposite; resonance and antiresonance frequencies; quality Q-factor; surface acoustic wave (SAW); interdigital transducer (IDT); mass load; SAW resonator
Online: 31 December 2019 (16:01:57 CET)
A novel effective vibrational mode was discovered in the conventional transducer with an array of orthogonal (square) regular piezoelectric rods in 1-3 piezocomposite, containing the damping backing and front matching layers. The operational resonance in the structure was determined as the Surface Acoustic Wave (SAW) on the backing boundary excited by the adjacent piezo-rods, with its frequency typically near 3 times lower the fundamental half-lambda conventional piezocomposite resonance. Pulse-echo sensitivity and transmitting sound-pressure-level (SPL) in air showed that the signal strength is roughly comparable to the industrial similar air transducers at the frequency range 100…700 kHz, where at these frequencies the lateral and longitudinal piezoelement dimensions in the conventional transducer design are typically close to each other causing interference with unwanted coupling modes. As was determined theoretically and proved in experiments, the backing SAW resonance effect in the transducer performance is inherent just to the regular periodic 1-3 piezocomposite structure, and does occur neither with randomly located/oriented piezo-rods, nor in the homogeneous piezo-plate at least with the same lateral cross-section as the connected to it backing. The purpose of the article is to investigate a newly discovered operational vibrational mode of a SAW type in 1-3 regular piezocomposite, other than piezoelectric resonance. The investigated phenomena can improve the transceiver sensitivity, bandwidth, providing lower drive voltage, and smaller and lighter weight ultrasonic transducers. Based on the piezocomposites with thickness’ 1…1.5 mm (rod resonance near 2…3 MHz), pillar width 0.2…0.8 mm, kerf width 0.1…0.4 mm, the transceivers with an operating frequency from 140 kHz to 650 kHz were designed and fabricated with a conventional backing of a mixture of high-density tungsten powder and epoxy, and a matching layer of a mixture of low-density glass bubbles and epoxy. Experimental evaluation of their acoustical performance showed expected characteristics suitable for practical applications.
ARTICLE Download: 47| View: 53| Comments: 0 | doi:10.20944/preprints201912.0411.v1
Subject: Engineering, Construction Keywords: safety; electrical contractors; construction accidents; nature and outcome of injuries; Chi-square test of independence
Online: 31 December 2019 (11:19:50 CET)
Electrical contractors have experienced a rise in occupational fatalities in recent years. In 2017, electrical contractors also had the second highest number of non-fatal injuries among specialty trade contractors. Identifying statistically significant dependencies between these catastrophic outcomes and a handful of well-defined contributing factors in construction accidents offers a first step in mitigating the risks of construction accidents in this trade. Therefore, this study used methodologies of descriptive and quantitative statistics to identify the contributing factors most affecting occupational accident outcomes among electrical contracting enterprises, given an accident occurred. Accident reports were collected from the Occupational Safety and Health Administration’s fatality and catastrophe database. To ensure the reliability of the data, the team manually codified more than 600 incidents through a comprehensive content analysis using injury-classification standards. Inclusive of both fatal and non-fatal injuries, the results showed that most accidents happened in nonresidential buildings, new construction, and small projects (i.e., $50,000 or less). The main source of injuries manifested in parts and materials (46%), followed by tools, instruments, and equipment (19%), and structure and surfaces (16%). The most frequent types of injuries were fractures (31%), electrocutions (27%), and electrical burns (14%); the main injured body parts were upper extremities (25%), head (23%), and body system (18%). Among non-fatal cases, falls (37%), exposure to electricity (36%), and contact with objects (19%) caused most injuries; among fatal cases, exposure to electricity was the leading cause of death (50%), followed by falls (28%) and contact with objects (19%). The analysis also investigated the impact of several accident factors on the degree of injuries and found significant effects from such factors such as project type, source of injury, cause of injuries, injured part of body, nature of injury, and event type. In other words, the statistical probability of a fatal accident—given an accident occurrence—changes significantly based on the degree of these factors. Beyond these outcomes, the described content-analysis methodology contributes to the accident-analysis body of knowledge by providing a framework for codifying data from accident reports to facilitate future analysis and modeling attempts (e.g., developing logistic regression models) to subsequently mitigate more injuries in other fields.
ARTICLE Download: 84| View: 73| Comments: 0 | doi:10.20944/preprints201912.0409.v1
Subject: Engineering, Electrical & Electronic Engineering Keywords: design optimization; evolutionary computation; finite element analysis; power transformers
Online: 31 December 2019 (10:42:23 CET)
Since large power transformers are custom-made, and their design process is a labor-intensive task, their design process is split into different parts. In tendering, the price calculation is based on the preliminary design of the transformer. Due to the complexity of this task, it belongs to the most general branch of discrete, non-linear mathematical optimization problems. Most of the published algorithms are using a copper filling factor based winding model to calculate the main dimensions of the transformer during this first, preliminary design step. Therefore, these cost optimization methods are not considering the detailed winding layout and the conductor dimensions. However, the knowledge of the exact conductor dimensions is essential to calculate the thermal behaviour of the windings and make a more accurate stray loss calculation. The paper presents a novel, evolutionary algorithm-based transformer optimization method which can determine the optimal conductor shape for the windings during this examined preliminary design stage. The accuracy of the presented FEM method was tested on an existing transformer design. Then the results of the proposed optimization method have been compared with a validated transformer design optimization algorithm.
ARTICLE Download: 76| View: 94| Comments: 0 | doi:10.20944/preprints201912.0408.v1
Subject: Engineering, Electrical & Electronic Engineering Keywords: VLBI; Geodesy; Radioastronomy; Radiotelescope; Receiver; Radiometer; Feed; Backend; Correlation; VGOS; RFI
Online: 31 December 2019 (10:27:51 CET)
This paper shows the development of a simultaneous tri-band (S: 2.2 - 2.7 GHz, X: 7.5 - 9 GHz and Ka: 28 - 33 GHz) low-noise cryogenic receiver for geodetic Very Long Baseline Interferometry (geo-VLBI) which has been developed by the technical staff of Yebes Observatory (IGN) laboratories in Spain. The receiver was installed in the first radio telescope of the Red Atlántica de Estaciones Geodinámicas y Espaciales (RAEGE) project, which is located in Yebes Observatory, in the frame of the VLBI Global Observing System (VGOS). After this, the receiver was borrowed by the Norwegian Mapping Autorithy (NMA) for the commissioning of two VGOS radiotelescopes in Svalbard (Norway). A second identical receiver was built for the Ishioka VGOS station of the Geospatial Information Authority (GSI) of Japan, and a third one for the second RAEGE VGOS station, located in Santa María (Açores Archipelago, Portugal). The average receiver noise temperatures are 21, 23 and 25 Kelvin and the measured antenna efficiencies are 70%, 75% and 60% in S-band, X-band and Ka-band, respectively.
ARTICLE Download: 64| View: 69| Comments: 0 | doi:10.20944/preprints201912.0405.v1
Subject: Engineering, Marine Engineering Keywords: Optimal design procedure; monitoring network; water quality; graphical optimization; objective mapping
Online: 31 December 2019 (10:17:53 CET)
The semi-enclosed estuary is very susceptible to changes in the physical and environmental characteristics of the inflow from the land and the coastal sea weather and so the continuous and comprehensive monitoring is necessary for managing the estuary. Nevertheless, the standard procedure or schematic framework has not been proposed appropriately to determine how many instruments are necessary and where they need to be deployed to detect critical changes. Therefore, the present work proposes a systematical strategy for the deployments of the monitoring array by using the combination of the graphical optimization with the objective mapping technique. In order to reflect the spatiotemporal characteristics of the bay, the representative variables and eigenvectors are determined by the Empirical Orthogonal Function (EOF), and the cosine angle among them are calculated for a design index of optimization. At the recommended locations, the sampled representative variables are interpolated to reconstruct their spatiotemporal distribution and compared with the distributions of the true values. Analysis confirms that the selected locations, even with a small number of points, can be used for on-site monitoring. Also, the present framework suggests how to determine installable regions for real-time monitoring stations, which reflect the global and local characteristics of the semi-enclosed estuary.
Mon, 30 December 2019
ARTICLE Download: 50| View: 53| Comments: 1
Subject: Engineering, Industrial & Manufacturing Engineering Keywords: Lean Healthcare; DMAIC; waste reduction; efficiency; sustainability
Online: 30 December 2019 (06:53:46 CET)
With an increasing demand for quality of care and lower costs, hospitals are looking for industry-based methods to improve efficiency in their processes. This study aims to reduce waste in a public hospital in Mexico by improving the medical supply process for the operating room. To this end, a lean healthcare (LH) implementation following the DMAIC approach (Define-Measure-Analyze-Improve-Control) is carried out. We analyze the value stream of the supply process, including main surgical procedures and their related medical supplies, and identify different causes of inefficiency, which are evaluated and controlled through different tools, including a value stream map, Kanban, and the 5S program. As a result, five types of waste were reduced. Over-processing requests were reduced by 15.3%, defective identification numbers were reduced by 46.5%, redundant processing was improved by 94.8%, near 2.8% of the unnecessary inventory was reduced, and transportation waste was reduced by up to 16.7%. Finally, the lead-time for the main supplies was reduced by 33 days. This work demonstrates that LH and DMAIC are effective in reducing waste and are highly conducive to improving sustainability in healthcare processes. Moreover, it provides practical insights for practitioners regarding the implementation of LH in public hospitals in developing countries.
Sun, 29 December 2019
ARTICLE Download: 44| View: 64| Comments: 1 | doi:10.20944/preprints201809.0015.v2
Subject: Engineering, Industrial & Manufacturing Engineering Keywords: supply chains; simulation model; contamination; variability; inventory levels; shipments
Online: 29 December 2019 (08:36:38 CET)
This article aims to serve as a guide for the construction of supply chain simulation models designed with a lean approach, using Promodel software. To achieve this, a supply chain was designed for a fictitious company located in the City of Celaya, Guanajuato and a set of suppliers located in different cities within the same State. It was used as a google tool to define the distances between each of the companies. As a final result, a representative model of a supply chain was obtained, as well as a methodology that allows the construction of lean supply chains regardless of the number of companies that comprise it. The effect of the variability in the delivery times between suppliers was incorporated into the simulation model, as well as an equation that calculates the pollution emissions of the vehicles that integrate the network that moves the products between the companies. With this work it is possible to represent networks of supply chains of real world companies, where the variability and contamination factor is included, to facilitate the decision making regarding the number of vehicles, inventory levels, quantities to be shipped, frequency in the shipments, etc. with the purpose of contaminating as little as possible and at the same time preventing interruptions in the supply chain using the least amount of resources possible.
ARTICLE Download: 55| View: 75| Comments: 0
Subject: Engineering, Biomedical & Chemical Engineering Keywords: microfabrication; microsystem; manufacturing; low-cost; scaling laws; lab-on-chip
Online: 29 December 2019 (07:16:11 CET)
Microsystems are key enabling technologies, with applications found in almost every industrial field, including in-vitro diagnostic, energy harvesting, automotive, telecommunication, drug screening, etc. Microsystems, such as microsensors and actuators, are typically made up of components below 1000 microns in size that can be manufactured at low-unit cost through mass-production. Yet, the development of microsystems for commercial or educational purposes, has typically been limited to upper income countries due to the initial investment costs associated with the microfabrication equipment and processes. However, recent technological advances have enabled the development of low-cost microfabrication tools. In this paper, we describe a range of low-cost approaches and equipment (below £1000), developed or adapted and implemented in our laboratories. We describe processes including photolithography, micromilling, 3D printing, xurography and screen-printing used for the microfabrication of structural and functional materials. The processes that can be used to shape a range of materials with sub-millimetre feature sizes are demonstrated here in the context of Lab-on-Chips, but they can be adapted for other applications. We anticipate that this paper, which will enable researchers to build a low-cost microfabrication toolbox in a wide range of settings, will spark a new interest in microsystems.
ARTICLE Download: 48| View: 62| Comments: 1 | doi:10.20944/preprints201905.0045.v2
Subject: Engineering, Energy & Fuel Technology Keywords: fuel cell; carbon nanotube; catalyst; platinum-ruthenium
Online: 29 December 2019 (07:06:08 CET)
Due to low working temperature, high energy density and low pollution, proton exchange fuel cells have been investigated under different operating conditions in different applications. Using platinum catalysts in methanol fuel cells leads to increasing the cost of this kind of fuel cell which is considered as a barrier to the commercialism of this technology. For this reason, a lot of efforts have been made to reduce the loading of the catalyst required on different supports. In this study, carbon black (CB) and carbon nanotubes (CNT) have been used as catalyst supports of the fuel cell as well as using the double-metal combination of platinum-ruthenium (PtRu) as anode electrode catalyst and platinum (Pt) as cathode electrode catalyst. The performance of these two types of electro-catalyst in the oxidation reaction of methanol has been compared based on electrochemical tests. Results showed that the carbon nanotubes increase the performance of the micro-fuel cell by 37% at maximum power density, compared to the carbon black. Based on thee-electrode tests of chronoamperometry and voltammetry, it was found that the oxidation onset potential of methanol for CNT has been around 20% less than CB, leading to the kinetic improvement of the oxidation reaction. The current density of methanol oxidation reaction increased up to 62% in CNT sample compared to CB supported one, therefore the active electrochemical surface area of the catalyst has been increased up to 90% by using CNT compared to CB which shows the significant rise of the electrocatalytic activity in CNT supported catalyst. Moreover, the resistance of the CNT supported sample to poisonous intermediate species has been found 3% more than CB supported one. According to the chronoamperometry test results, it was concluded that the performance and sustainability of the CNT electro-catalyst show remarkable improvement compared to CB electro-catalyst in the long term.
ARTICLE Download: 135| View: 119| Comments: 0 | doi:10.20944/preprints201912.0369.v1
Subject: Engineering, Civil Engineering Keywords: Virtual Reality; Augmented Reality; Building Information Modeling; industry trend; virtual environment
Online: 29 December 2019 (04:42:10 CET)
With advances in Building Information Modeling (BIM), Virtual Reality (VR) and Augmented Reality (AR) technologies have many potential applications in the Architecture, Engineering, and Construction (AEC) industry. However, the AEC industry, relative to other industries, has been slow in adopting AR/VR technologies, partly due to lack of feasibility studies examining the actual cost of implementation versus an increase in profit. The main objectives of this paper are to understand the industry trends in adopting AR/VR technologies and identifying gaps within the industry. The identified gaps can lead to opportunities for developing new tools and finding new use cases. To achieve these goals, two rounds of a survey at two different time periods (a year apart) were conducted. Responses from 158 industry experts and researchers were analyzed to assess the current state, growth, and saving opportunities for AR/VR technologies for the AEC industry. The findings demonstrate that older generations are significantly more confident about the future of AR/VR technologies and they see more benefits in AR/VR utilization. Furthermore, the research results indicate that Residential and commercial sectors have adopted these tools the most, compared to other sectors and institutional and transportation sectors had the highest growth from 2017 to 2018. Industry experts anticipated a solid growth in the use of AR/VR technologies in 5 to 10 years, with the highest expectations towards healthcare. Ultimately, the findings show a significant increase in AR/VR utilization in the AEC industry from 2017 to 2018.
Fri, 27 December 2019
ARTICLE Download: 104| View: 110| Comments: 0 | doi:10.20944/preprints201912.0357.v1
Subject: Engineering, Biomedical & Chemical Engineering Keywords: microfluidics; immunophenotyping; FISH; liquid biopsy; circulating leukemia cells; circulating plasma cells
Online: 27 December 2019 (02:30:15 CET)
The role of circulating plasma cells (CPCs) and circulating leukemic cells (CLCs) as biomarkers for several blood cancers, such as multiple myeloma and leukemia, respectively, have recently been reported. These markers can be attractive due to the minimally invasive nature of their acquisition through a blood draw (i.e., liquid biopsy) negating the need for painful bone marrow biopsies. CPCs or CLCs can be used for cellular/molecular analyses, such as immunophenotyping or fluorescence in situ hybridization (FISH). FISH, which is typically carried out on slides involving complex workflows, becomes problematic when operating on CLCs or CPCs due to their relatively modest numbers. Here, we present a microfluidic device for characterizing CPCs and CLCs enriched from peripheral blood using immunofluorescence or FISH. The microfluidic possessed an array of cross-channels (2-4 µm in depth and width) that interconnected a series of input and output fluidic channels. Placing a cover plate over the device formed microtraps, the size of which was defined by the width and depth of the cross-channels. This microfluidic chip allowed for automating immunofluorescence and FISH requiring the use of small volumes of reagents, such as antibodies and probes, as compared to slide-based immunophenotyping and FISH. In addition, the device could secure FISH results in <4 h compared to 2-3 d for conventional FISH.
Thu, 26 December 2019
ARTICLE Download: 27| View: 21| Comments: 0
Subject: Engineering, Other Keywords: energy performance; co2 emission; cogenerated heat and power (chp); organic rankin cycle (orc)
Online: 26 December 2019 (12:32:17 CET)
The paper presents the results of energy and environmental analysis of geothermal CHP plant operation in Polish conditions. As the most favorable, for the geothermal conditions prevailing in Poland, the variant of CHP plant based on Organic Rankine Cycle (ORC) has been taken into consideration. As the case study the existing geothermal well located in the town of Konin in the Wielkopolska voivodship has been chosen. The conceptual design of CHP plant has been proposed and evaluated from energy and environmental point of view. As energy performance criteria the non-renewable primary energy consumption has been chosen. In case of environmental performance carbon dioxide emission has been taken as evaluation criteria. The analysis has been performed for different operating conditions and three working fluids.
ARTICLE Download: 51| View: 46| Comments: 0 | doi:10.20944/preprints201912.0349.v1
Subject: Engineering, Mechanical Engineering Keywords: verification and validation; computational thermal analysis; computational physics
Online: 26 December 2019 (02:35:47 CET)
In the power plant industry, the turbine inlet temperature (TIT) plays a key role in the efficiency of the gas turbine and, therefore, the overall—in most cases combined—thermal power cycle efficiency. Gas turbine efficiency increases by increasing TIT. However, an increase of TIT would increase the turbine component temperature which can be critical (e.g., hot gas attack). Thermal barrier coatings (TBCs)—porous media coatings—can avoid this case and protect the surface of the turbine blade. This combination of TBC and film cooling produces a better cooling performance than conventional cooling processes. The effective thermal conductivity of this composite is highly important in design and other thermal/structural assessments. In this article, the effective thermal conductivity of a simplified model of TBC is evaluated. This work details a numerical study on the steady-state thermal response of two-phase porous media in two dimensions using personal finite element analysis (FEA) code. Specifically, the system response quantity (SRQ) under investigation is the dimensionless effective thermal conductivity of the domain. A thermally conductive matrix domain is modeled with a thermally conductive circular pore arranged in a uniform packing configuration. Both the pore size and the pore thermal conductivity are varied over a range of values to investigate the relative effects on the SRQ. In this investigation, an emphasis is placed on using code and solution verification techniques to evaluate the obtained results. The method of manufactured solutions (MMS) was used to perform code verification for the study, showing the FEA code to be second-order accurate. Solution verification was performed using the grid convergence index (GCI) approach with the global deviation uncertainty estimator on a series of five systematically refined meshes for each porosity and thermal conductivity model configuration. A comparison of the SRQs across all domain configurations is made, including uncertainty derived through the GCI analysis.
Wed, 25 December 2019
ARTICLE Download: 43| View: 50| Comments: 0
Subject: Engineering, Mechanical Engineering Keywords: diesel engine; fault diagnosis; variational mode decomposition; random forest; feature extraction
Online: 25 December 2019 (11:13:13 CET)
Diesel engines, as power equipment, are widely used in the fields of automobile industry, ship and power equipment. Due to wear or faulty adjustment, the valve train clearance abnormal fault is a typical failure of diesel engines, which may result in the performance degradation, even valve fracture and cylinder hit fault. However, the failure mechanism features mainly in time domain and angular domain, on which the current diagnosis methods based, are easily affected by working conditions or hard to extract accurate enough, as the diesel engine keeps running in transient and non-stationary process. This work arms at diagnosing this fault mainly based on frequency band features which would change when the valve clearance fault occurs. For the purpose of extracting a series of frequency band features adaptively，a decomposition technique based on improved variational mode decomposition is investigated in this work. As the connection between the features and the fault is fuzzy, the random forest algorithm is used to analyze the correspondence between features and faults. In addition, the feature dimension is reduced to improve the operation efficiency according to importance score. The experimental results under variable speed condition show that the method based on variational mode decomposition and random forest is capable to detect valve clearance fault effectively.
ARTICLE Download: 36| View: 34| Comments: 0
Subject: Engineering, General Engineering Keywords: wastewater treatment; electrocoagulation; electrokinetics; industrial wastewater; industrial size experiment
Online: 25 December 2019 (09:30:22 CET)
The environmental policy is compelling industries to treat their wastewater to a level that can be released into the domestic sewer system or even for reuse. However, many industrial branches are lacking space for traditional wastewater plant. Hence, electrokinetics wastewater treatment is a viable alternative as it is fast and does not require large space. However, the electrokinetics wastewater treatment is still mostly tested in the laboratory. In the current study, a prototype of electrokinetics wastewater treatment industrial-size device has been designed, constructed and tested under real conditions. In this paper the device is described and the results obtained from the operation of the device are presented and discussed.
Tue, 24 December 2019
COMMUNICATION Download: 40| View: 31| Comments: 0
Online: 24 December 2019 (11:36:03 CET)
VHF Data Exchange System (VDES) is considered as an important component of the future maritime communication system by the International Maritime Organization (IMO). On the basis of existing Automatic Identification System (AIS), VDES adds the other two higher capacity subsystems: Application Specific Message (ASM) and VHF Data Exchange (VDE). The Random Access Channel (RACH) of VDE was first introduced in the International Telecommunication Union (ITU) Recommendation M.2092-0. As the slot planning of RACH in VDE is interval, which is significantly different from the continuous slot map for access algorithms in AIS, the existing slot access algorithms cannot meet the requirements of VDE. The simulation results show that the VDE slot map can reduce the normalized throughput of the existing algorithm by 39%. A novel random access algorithm called Adaptive Traffic Load Contention Resolution Diversity Slotted ALOHA (ATL-CRDSA) is proposed in this paper. The algorithm combines the load control strategy and contention resolution scheme to overcome the challenges of the new RACH of VDE. Simulation results show that ATL-CRDSA has remarkable improvement on RACH, and makes RACH very efficient and provides low latency of the packets. The insights gained from this study may be of assistance to the Media Access Control (MAC) layer design for upcoming versions of VDES standard.
ARTICLE Download: 66| View: 60| Comments: 0 | doi:10.20944/preprints201912.0318.v1
Subject: Engineering, Marine Engineering Keywords: Hull-propeller interaction; Full-scale CFD; Scale effect; Self-propulsion; Statistical sea trails
Online: 24 December 2019 (11:16:25 CET)
Accurate prediction of the self-propulsion performance is one of the most important factors for energy-efficient design of a ship. In general, the hydrodynamic performance of a full-scale ship could be achieved by model-scale simulation or towing tank test with extrapolations. With the development of CFD methods and computing power, directly predict ship performance with full-scale CFD is an important approach. In this article, a numerical study on the full-scale self-propulsion performance with propeller operating behind ship at model- and full-scale is presented. The study includes numerical simulations using RANS method with double-model and VOF model respectively and scale effect analysis based on overall performance, local flow fields and detailed vortex identification. Verification study on grid convergence is also performed for full-scale simulation with global and local mesh refinements. And a series of sea trail tests were performed to collect reliable data for the validation of CFD predictions. The analysis of scale effect on hull-propeller interaction shows that the difference on hull boundary layer and flow separation is the main source of scale effect on ship wake. And the results of the fluctuations of propeller thrust and torque along with circulation distribution and local flow field show that propeller’s loading is significantly higher for model-scale ship. It is suggested that the difference on vortex evolution and interaction is more pronounced and have larger effects on ship’s powering performance at model-scale than full-scale according to the simulation results. From the study on self-propulsion prediction, it could be concluded that the simplification on free surface treatment does not only affect the wave-making resistance for bare hull but also the propeller performance and propeller induced ship resistance which can produced up to 5% uncertainty to the power prediction. Roughness is another important factor in full-scale simulation because it has up to approximately 7% effect on the delivery power. As a result of validation study, the numerical simulations of full-scale ship self-propulsion shows good agreement with the sea trail data especially for cases that have considered both roughness and free surface effects. This result will largely enhance our confidence to apply full-scale simulation in the prediction of ship’s self-propulsion performance in the future ship designs.
ARTICLE Download: 56| View: 60| Comments: 0 | doi:10.20944/preprints201912.0317.v1
Subject: Engineering, Mechanical Engineering Keywords: Cavitation jet; Finite volume method; Structural parameters; Numerical Simulation
Online: 24 December 2019 (11:12:20 CET)
In order to reveal the mechanism and influencing factors of high pressure jet cavitation of nozzle in submerged environment, this study focused on the evolutionary process of cavitation bubbles and combined finite volume method and mixed multi-phase flow model to analyze the cavitation, velocity distribution and experimental cavitation intensity of fishing net cleaning equipment. Results show that the cavitation inception, growth and collapse mainly occurred in the peripheral region of the flow field. Ring-shaped cavitation erosion zone appeared on the test sample target. A lot of small dense erosion pits were densely distributed in the ring-shaped erosion zone, erosion marks were observed in the center. The cavitation erosion intensity was greatly affected by the nozzle structure. As the diameter of nozzle increased from 0.6 mm to 1 mm, the maximum gas volume fraction increased by 8.53%. The nozzle outlet enlargement angle greatly increased the cavitation intensity. The nozzle with an outlet angle of 30° exhibited the optimal cavitation erosion performance . The cavitation volume fraction of the nozzle with short necking structure was slightly larger than that of the nozzle with long necking structure at the same level in the necking length rang of 3mm to 7mm. In terms of the influence of nozzle structure on the cavitation erosion effect, the nozzle diameter D ranked the first, followed by the outlet angle α, and the necking length L was at the last.
ARTICLE Download: 52| View: 73| Comments: 0 | doi:10.20944/preprints201912.0312.v1
Subject: Engineering, Civil Engineering Keywords: thermal comfort; draught; cooling period; open office
Online: 24 December 2019 (08:42:03 CET)
Local thermal comfort (TC) and draught rate (DR) has been studied widely. There has been more meaningful research performed in controlled boundary condition situations than in actual work environments involving occupants. TC conditions in office buildings in Estonia have been barely investigated in the past. In this paper, the results of TC and DR assessment in five office buildings in Tallinn are presented and discussed. Studied office landscapes vary in heating, ventilation and cooling (HVAC) system parameters, room units and elements. All sample buildings were less than six years old, equipped with dedicated outdoor air ventilation system and room conditioning units. The on-site measurements consisted of TC and DR assessment with indoor climate questionnaire (ICQ). The purpose of the survey is to assess the correspondence between HVAC design and the actual situation. Results show, whether and in what extent the standard-based criteria for TC is suitable for actual usage of the occupants. Preferring one room conditioning unit type or system may not guarantee better thermal environment without draught. Although some HVAC systems observed in this study should create the prerequisites for ensuring more comfort, results show that this is not the case for all buildings in this study.
Sun, 22 December 2019
ARTICLE Download: 123| View: 35| Comments: 0
Subject: Engineering, General Engineering Keywords: guided artillery rockets; rocket launcher aircraft
Online: 22 December 2019 (14:21:36 CET)
A concept of guided artillery rockets with reusable ﬁrst stage otherwise called a rocket launcher aircraft (RLA) is presented. RLA raises the second stage rockets (SSR) to an altitude of up to 20 km. While RLA is moving at low supersonic speed, it releases one or more SSRs. RLA returns to the base within a few minutes of it’s launch. SSRs use slow burning motors to gain altitude and velocity. At the apogee of their ﬂight SSRs release projectiles which ﬂy to the target and strike it at high impact velocity. The projectiles reach a target at ranges of up to 374 km and impact velocity up to 1.35 km/s. We show that a rocket launched at high altitude and high initial velocity does not need expensive thermal protection to survive ascent. Delivery of munitions to target by the system described should be much less expensive than delivery by a conventional rocket. All parameters of RLA, SSR, and their trajectories are calculated based on theoretical (mechanical and thermo-dynamical) analysis and on several MatLab programs.
ARTICLE Download: 46| View: 41| Comments: 0
Subject: Engineering, General Engineering Keywords: damage and defect assessment; magnetic resonance imaging; polymer matrix composite
Online: 22 December 2019 (10:55:03 CET)
Damaged and defective fiber-reinforced polymer composites were inspected by magnetic resonance imaging. Nondestructive examination was conducted with samples immersed in saline water solution simulating biofluids permanently in contact with load-bearing orthopedic implants. Size, geometry, orientation and positioning of translaminar and delamination fractures in the test pieces were characterized. In this regard, translaminar damages required all primary imaging planes, namely, axial, coronal and sagittal to be fully portrayed, whereas only sagittal slicing was demanded for entire depiction of delaminations. Size and spatial distribution of water clusters formed in composite samples, as well as surface finishing features of the specimens were also outlined. The evaluated imaging technique has shown high potential for nondestructive inspection of fiber-reinforced polymer parts operating in liquid proton-rich media.
ARTICLE Download: 46| View: 58| Comments: 0
Subject: Engineering, Control & Systems Engineering Keywords: textile reinforced composite; shape memory alloy; robust stability
Online: 22 December 2019 (01:56:09 CET)
This paper develops the mathematical modeling and deflection control of a textile-reinforced composite integrated with shape memory actuators. The model of the system is derived using identification method and unstructured uncertainty approach. Based on this model and robust stability analysis a robust proportional-integral controller is designed for controlling the deflection of the composite. The performance of the proposed controller is compared with a classical one through experimental analysis.
Fri, 20 December 2019
REVIEW Download: 182| View: 97| Comments: 0 | doi:10.20944/preprints201912.0276.v1
Subject: Engineering, Other Keywords: IoT in Healthcare; IoT in Vehicular Networks; Behaviors and Decision Making, IoT in Learning Environments; IoT in Mining; Io IoT in Energy Systems; IoT in Smart Cities; Sensors; Low Power Networks
Online: 20 December 2019 (12:37:09 CET)
With Internet of Things (IoT) gaining presence throughout different industries a lot of new technologies have been introduced to support this undertaking. Implications on one such technology, wireless systems allowed for the use of different communication methods to achieve the goal of transferring data reliably, with more cost efficiency and over longer distances. Anywhere from a single house with only a few IoT devices such as a smart light bulb or a smart thermostat connected to the network, all the way to a complex system that can control power grids throughout countries, IoT has been becoming a necessity in everyday lives. This paper presents an overview of the devices, systems and wireless technologies used in different IoT architectures (Healthcare, Vehicular Networks, Mining, Learning, Energy, Smart Cities, Behaviors and Decision Making), their upbringings and challenges to this date and some foreseen in the future.
Thu, 19 December 2019
ARTICLE Download: 44| View: 54| Comments: 0 | doi:10.20944/preprints201912.0259.v1
Subject: Engineering, Biomedical & Chemical Engineering Keywords: hydrate; propane; normal butane; equilibrium pressure
Online: 19 December 2019 (13:10:12 CET)
The purpose of this study is to determine the equilibrium conditions for the formation of a mixture of propane and normal butane hydrates including temperature, pressure and mole fraction. In order to prevent the formation of hydrates in the cooling path, it is necessary to examine the conditions of hydrate formation and provide solutions. Modeling of hydrate formation conditions was performed using Hydoff software and compared with experimental results in this field, which obtained an acceptable error percentage. The range of temperature is between 267-276 °C and the molar percentage of propane is 0.7,0.8 and 0.9 and the mathematical equation was presented to predict hydrate formation. By analyzing the results, it was found that by increasing the concentration of ethane in the presence of other compounds, hydrate growth increased and hydrates formed more stable, also by increasing the concentration of propane and normal butane the amount of equilibrium pressure will decrease.
TECHNICAL NOTE Download: 51| View: 66| Comments: 0 | doi:10.20944/preprints201912.0256.v1
Subject: Engineering, Electrical & Electronic Engineering Keywords: PAPR; HPA; OPS-SAP; PER; fading models
Online: 19 December 2019 (09:13:40 CET)
Peak-to-Average Power Ratio (PAPR) is one of the main problems in wireless communications using Orthogonal Frequency Division Multiplexing (OFDM). Its behavior is random and can produce problems for the hardware implementation, directly influencing the Packet Error Rate (PER). In this article, the PER is obtained for channels with Rayleigh and Rician fading. In the simulation, a High Power Amplifier (HPA) is added to the transmitter and for PAPR reduction Simple Amplitude Predistortion-Orthogonal Pilot Sequences (OPS-SAP) technique is used.
TECHNICAL NOTE Download: 51| View: 64| Comments: 0 | doi:10.20944/preprints201912.0255.v1
Subject: Engineering, Electrical & Electronic Engineering Keywords: OFDM; PAPR; passband; IEEE 802.11p
Online: 19 December 2019 (08:54:52 CET)
Orthogonal Frequency Division Multiplexing (OFDM) is a technique widely used in today's wireless communication systems due to its ability to combat the effects of multi-path in the signal. However, one of the main limitations of the use of OFDM is its high Peak-to-Average Power Ratio (PAPR), which reduces the efficiency of the OFDM system. The effects of PAPR can produce both out-of-band and in-band radiation, which degrades the signal by increasing the bit error rate (BER), this occurs in both baseband and bandpass sginals. In this document the effect of the PAPR in a OFDM passband signal is analyzed considering the implementation of a High Power Amplifier (HPA) and the Simple Amplitude Predistortion-Orthogonal Pilot Sequences (OPS-SAP) scheme to reduce the PAPR.
ARTICLE Download: 50| View: 90| Comments: 0 | doi:10.20944/preprints201912.0240.v1
Subject: Engineering, Energy & Fuel Technology Keywords: dynamic thermos-physical characteristics; hydrocarbon fuel; thermal power generation (TPG); thermo-mechanical coupling effect; hypersonic air-breathing propulsion
Online: 19 December 2019 (05:30:03 CET)
The aspirated hypersonic air-breathing propulsion system requires a large amount of power generation, but its special structure makes it impossible to adopt common power generation methods. The high-temperature gaseous hydrocarbon fuel thermal power generation (TPG) system was developed to solve the power generation problem for hypersonic air-breathing propulsion system. But off-design operating conditions of the hypersonic propulsion system results in a more complex process for both propulsion system and the TPG system. To better analyzing the dynamic thermos-physical characteristics of hypersonic airbreathing propulsion system considering thermal-mechanical coupling process among cooling/TPG system, a dynamic analytical model was developed, and the dynamic thermos-physical characteristics of TPG system under different off-design working conditions were conducted. It can be concluded from the analytical results that the dynamic process of thermos-physical characteristics shows a complex trend under the flight Mach number and fuel equivalence ratio off-design working conditions. Such complexity of dynamic characteristics brings difficulties in fuel supply for the propulsion system.
Wed, 18 December 2019
ARTICLE Download: 96| View: 151| Comments: 4 | doi:10.20944/preprints201912.0237.v1
Subject: Engineering, Mechanical Engineering Keywords: tomato harvesting; gripper; continuum robot; tomato detection; design; agricultural robot
Online: 18 December 2019 (04:34:30 CET)
Designing and development of agricultural robot is always a challenging issue, because of robot intends to work an unstructured environment and at the same time, it should be safe for the surrounded plants. Therefore, traditional robots cannot meet the high demands of modern challenges, such as working in confined and unstructured workspaces. Based on current issues, we developed a new tomato harvesting wire-driven discrete continuum robot arm with a flexible backbone structure for working in confined and extremely constrained spaces. Moreover, we optimized a tomato detaching process by using newly designed gripper with passive stem cutting function. Moreover, by designing the robot we also developed ripe tomato recognition by using machine learning. This paper explains the proposed continuum robot structure, gripper design, and development of tomato recognition system.
Tue, 17 December 2019
ARTICLE Download: 70| View: 59| Comments: 0 | doi:10.20944/preprints201912.0230.v1
Subject: Engineering, Industrial & Manufacturing Engineering Keywords: Lean Healthcare; DMAIC; waste reduction; efficiency; sustainability
Online: 17 December 2019 (10:53:40 CET)
Hospitals face challenges to improve efficiency in order to meet an increasing demand for high quality of care and low costs. Industry-based methods such as lean healthcare (LH) are implemented to improve healthcare systems. This study presents a LH implementation following the DMAIC approach (Define-Measure-Analysis-Improve-Control) in a Mexican public hospital, and contributes to the literature by analyzing the relation of waste reduction and sustainability. We focused on improving the medical supply chain from a temporary warehouse (TW) to the operating room (OR). Therefore, we analyzed the value stream including main surgical procedures and their related medical supplies, and identified different causes of inefficiency, which were evaluated and controlled. As a result, five types of waste were reduced through different tools including: value stream map, Kanban, 5’s, among others. Over-processing requests were reduced 15.3%; similarly, defective identification numbers were reduced up to 46.5%, redundant processing was improved by 94.8%, unnecessary inventories were reduced near to 2.8% of the TW inventory, and transportation waste was reduced up to 16.7%. As a consequence, the lead-time for the main supplies was reduced 33 days. Results indicate that LH and DMAIC are effective to reduce waste and highly conducive to improve healthcare process sustainability.
ARTICLE Download: 47| View: 42| Comments: 0 | doi:10.20944/preprints201912.0229.v1
Subject: Engineering, Civil Engineering Keywords: masonry structures; stiffening walls; wall joints; connectors; bed joint reinforcement
Online: 17 December 2019 (10:46:57 CET)
Joints between walls are very important for structural analysis of each masonry building at the global and local level. This issue was often neglected in case of traditional joints and relatively squat walls. Nowadays the issue of wall joints is becoming particularly important due to the continuous strive for simplifying structures, introducing new technologies and materials. Eurocode 6 and other standards (USA, Canadian, Chinese, and Japanese) recommend inspecting joints between walls, but no detail procedures have been specified. This paper presents our own tests on joints between walls made of autoclaved aerated concrete (AAC) masonry units. Tests included reference models composed of two wall panels joined perpendicularly with a masonry bond (6 models), traditional steel and modified connectors (12 models). A shape and size of test models and structure of a test stand were determined on the basis of the analysis of the current knowledge, pilot studies and numerical analyses of FEM. The analysis referred to the morphology and failure mechanism of models. Load-displacement relationships for different types of joints were compared and obtained results were referred to results for reference models. A mechanism of cracking and failure was found to vary, and clear differences in behaviour and load capacity of each type of joints were observed. Individual working phases of joints were determined and defined, and the empirical approach was suggested to determine forces and displacement of wall joints.
ARTICLE Download: 73| View: 72| Comments: 0 | doi:10.20944/preprints201912.0223.v1
Subject: Engineering, Electrical & Electronic Engineering Keywords: laser dynamics; parallel computing; cellular automatas; GPUs and Multi-Core processors performance
Online: 17 December 2019 (09:48:23 CET)
In this paper we show how to efficiently implement parallel discrete simulations on Multi-Core and GPU architectures through a real example of application: a cellular automata model of laser dynamics. We describe the techniques employed to build and optimize the implementations using OpenMP and CUDA frameworks. We have evaluated the performance on two different hardware platforms that represent different target market segments: high-end platforms for scientific computing, using an Intel Xeon Platinum 8259CL server with48cores and also an NVIDIA Tesla6V100 GPU, both running on Amazon Web Server (AWS) Cloud, and on a consumer-oriented platform, using an Intel Core i9 9900k CPU and an NVIDIA GeForce GTX 1050 TI GPU. Performance results are compared and analysed in detail. We show that excellent performance and scalability can be obtained in both platforms, and we extract some important issues that imply a performance degradation for them. We also found that current Multi-Core CPUs with large core numbers can bring a performance very near to that of GPUs, even similar in some cases.
Mon, 16 December 2019
ARTICLE Download: 40| View: 37| Comments: 0
Subject: Engineering, Electrical & Electronic Engineering Keywords: arm motion recognition; micro-doppler signature; time series analysis; dynamic time warping; long short-term memory
Online: 16 December 2019 (11:42:44 CET)
Hand and arm gesture recognition using radio frequency (RF) sensing modality proves valuable in man-machine interface and smart environment. In this paper, we use time series analysis method for accurately measuring the similarity of the micro-Doppler (MD) signatures between the training and test data, thus providing improved gesture classification. We characterize the MD signatures by the maximum instantaneous Doppler frequencies depicted in the spectrograms. In particular, we apply the dynamic time warping (DTW) method and compare its performance with that of the long short-term memory (LSTM) network. Both methods take into account the values as well as the temporal evolution and trends of time series data. It is shown that the DTW method achieves high gesture classification rates and is robust to time misalignment.
ARTICLE Download: 44| View: 56| Comments: 1 | doi:10.20944/preprints201912.0023.v2
Subject: Engineering, Biomedical & Chemical Engineering Keywords: dielectrophoresis; microparticles; chromatography; separation; polarizability
Online: 16 December 2019 (11:21:18 CET)
The separation of microparticles with respect to different properties such as size and material is a research field of great interest. Dielectrophoresis, a phenomenon which is capable of addressing multiple particle properties at once, can be used to perform a chromatographic separation. However, the selectivity of current dielectrophoretic particle chromatography (DPC) techniques is limited. Here we show a new approach for DPC based on differences in the dielectrophoretic mobilities and the crossover frequencies of polystyrene particles. Both differences are addressed by modulating the frequency of the electric field to generate positive and negative dielectrophoretic movement to achieve multiple trap and release cycles of the particles. A chromatographic separation of different particle sizes revealed a voltage dependency of this method. Additionally, we showed the frequency bandwidth influence on separation using one example. The DPC method developed was tested with model particles but offers possibilities to separate a broad range of plastic and metal microparticles or cells and to overcome currently existing limitations in selectivity.
ARTICLE Download: 57| View: 47| Comments: 0 | doi:10.20944/preprints201912.0210.v1
Subject: Engineering, Civil Engineering Keywords: smart dashboard; smart governance; slow tourism; Santa Barbara Walk; Sulcis - Iglesiente; Sardinia; Italy
Online: 16 December 2019 (07:11:11 CET)
Information and communication technologies play an increasingly important role in the process of acquiring knowledge from a territory and managing it at different scales. ICTs allow a rapid diffusion of data not only through institutional channels but also through social networks where the smart community share experiences and perceptions. In this sense, ICTs become strategic to support the promotion of sustainable tourism development of territories. An important tool to implement it, can be a circular smart dashboard, a decision support system in which the digital data are organized and processed to produce an information output, to be used, after the evaluation by the decision makers, as a new input for the system. The present paper deals with a wider research the authors are involved in, related to the reconversion and valorization of a former mining area towards slow tourism, as the Santa Barbara Walk (SBW), an ancient mining route in the Sulcis Iglesiente area (Sardinia, Italy) . In particular, we here focus on the design proposal of a dashboard, capable of organizing information concerning the main features of the walk, in order to facilitate a shared governance for an effective tourism promotion. The paper is based on a thorough recognition of the main characteristics of the Walk, both the material ones and the digital, immaterial ones. The SBW represents in fact a network connecting the main points of interest along the Walk. On the contrary, its digital network – consisting of intangible infrastructure and flows - is however fragmented in terms of policies and contents Also a state of disorganization in slow tourism promotion activities can be observed. The goal of this paper is to present and analysis of the area, and to propose an evaluation and planning tool as the design of a circular dashboard of the SBW.
ARTICLE Download: 59| View: 40| Comments: 0 | doi:10.20944/preprints201912.0207.v1
Subject: Engineering, Mechanical Engineering Keywords: press bending; orbital auto welding; steel-tube correction; STKN540B; high-strength steel tube; manufacturing process
Online: 16 December 2019 (06:20:58 CET)
The purpose of this study is to propose a consecutive manufacturing process system to secure the productivity of excellent STKN540B steel tube in the respect of economy and safety as the supporting material for mega structures such as building, bridge and ship. The components of consecutive manufacturing are press-bending, orbital auto welding and steel tube correction. By using STKN540B a high-strength steel material with low yield point that requires a special manufacturing process unlike other steel materials, an actual tube manufacturing is carried out at each stage in this experimental study. With this, the quality of steel tube and the efficiency of the manufacturing process are analyzed to draw out some points to improve in the future.
ARTICLE Download: 63| View: 56| Comments: 0 | doi:10.20944/preprints201912.0204.v1
Subject: Engineering, Automotive Engineering Keywords: diesel engines; numerical simulation; pollutant emissions prediction; computational fluid dynamics
Online: 16 December 2019 (05:09:55 CET)
In this paper an integrated methodology for the coupling between 1D- and 3D-CFD simulation codes is presented, which has been developed to support the design and calibration of new diesel engines. The aim of the proposed methodology is to couple 1D engine models, which may be available in the early-stage engine development phases, with 3D predictive combustion simulations, in order to obtain reliable estimates of engine performance and emissions for newly designed automotive diesel engines. The coupling procedure features simulations performed in 1D-CFD by means of GT-SUITE and in 3D-CFD by means of Converge, executed within a specifically designed calculation methodology. An assessment of the coupling procedure has been performed by comparing its results with experimental data acquired on an automotive Diesel engine, considering different working points including both part load and full load conditions. Different multiple injection schedules have been evaluated for part-load operation, including pre and post injections. The proposed methodology, featuring detailed 3D chemistry modeling, was proven to be capable to properly assess pollutant formation, specifically to estimate NOx concentrations. Soot formation trend was also well-matched for most of the explored working points. The proposed procedure can therefore be considered as a suitable methodology to support the design and calibration of new Diesel engines, thanks to its ability to provide reliable engine performance and emissions estimations from the early-stage of a new engine development.
Sun, 15 December 2019
ARTICLE Download: 44| View: 35| Comments: 0 | doi:10.20944/preprints201912.0201.v1
Subject: Engineering, Electrical & Electronic Engineering Keywords: Debye model; dielectric properties; power transformers; spectroscopy; recovery voltage measurement (RVM); oil-paper insulation
Online: 15 December 2019 (16:09:57 CET)
The aim of this document is to present how the interpretation of the RVM (Recovery Voltage Measurement) test can be improved through the use of a Debye equivalent circuit. As it is described in the literature the interpretation of the RVM test requires expertise and if the transformer presents a high interfacial polarization it is not possible to diagnose it in detail. Debye model is proposed in this work for enhancing RVM interpretation. This model is based on an electrical circuit that includes basic R-L-C components, that allows two interesting features: on one hand, isolation physical effects can be separately represented and, on the other, the values of the R-C components can be calculated from the RVM response (L components are not used in this work as long as no magnetic field effects are taken into account). Thus, the different isolation effects that are indistinguishable merged in the RVM transient response can be split into different R-C branches, each one corresponding with a single (not merged) isolation effect. Finally, several case studies are presented, in which it is correlated a dielectric oil treatment carried out and the equivalent circuit changes.
ARTICLE Download: 59| View: 70| Comments: 0 | doi:10.20944/preprints201912.0197.v1
Subject: Engineering, Biomedical & Chemical Engineering Keywords: chaotic advection; microfluidics; micromixer; numerical simulation; process intensification
Online: 15 December 2019 (15:31:48 CET)
In the present paper four passive micromixers designs (G1, G2, G3 and G4) inspired on distillation columns trays were proposed. The devices performance was assessed by numerical simulations. The mixing performance was investigated for a Reynolds number range from 0.01 to 100 and channel height of 200 µm, 500 µm and 1000 µm for oil/ethanol flow. G1 and G4 designs provided high mixing index (> 0.975). The G1 device achieved superior mixing performance with a moderate pressure drop (about 0.5 MPa) due to the induced flow recirculation pattern for a relative high flow rate of 0.21 L/min, highlighting the potential use of such microdevice for scale-up and numbering-up of microdevices in modular chemical plant processing.
ARTICLE Download: 110| View: 358| Comments: 0 | doi:10.20944/preprints201912.0195.v1
Subject: Engineering, General Engineering Keywords: holographic 3D display; computer generated holography; light field image rendering; pinhole array
Online: 15 December 2019 (14:58:44 CET)
A fast calculation method for the full parallax high-resolution hologram is proposed based on the elemental light field image (EI) rendering. A 3D object located near the holographic plane is firstly rendered as multiple EIs with a pinhole array. Each EI is interpolated and multiplied by a divergent sphere wave and interfered with a reference wave to form a hogel. Parallel acceleration is used to calculate the high-resolution hologram because calculation of each hogel is independent. A high-resolution hologram with four billion pixels is calculated only within 8 minutes. Full parallax high-resolution 3D displays are realized by optical reconstructions.
Fri, 13 December 2019
ARTICLE Download: 54| View: 60| Comments: 0 | doi:10.20944/preprints201912.0182.v1
Subject: Engineering, Civil Engineering Keywords: co$_2$ sequestration; multifield analysis; unified pipe-network method; reactive portland cement
Online: 13 December 2019 (10:48:44 CET)
The underground injection and geological sequestration of carbon dioxide (CO2) is a promising approach for reducing the levels of CO2 in the atmosphere. To mitigate the leakage of CO2 resulting from natural fracture networks in rock masses, the sequestration process is commonly accompanied by the injection of reactive Portland cement representing a coupled hydro-chemo-mechanical process. In this work, a numerical approach based on the unified pipe network method (UPM) is presented that considers the coupled permeation and diffusion processes with chemical precipitation. Most input parameters are derived from the published literature. The proposed approach is validated through a comparison with analytical solutions, which are applied to simulate the CO2 sequestration process in a fractured rock mass. The results indicate that the long-term sequestration effect, which is highly influenced by the fracture distribution, can be captured effectively by the model. Consequently, the presented approach can assist engineers in properly designing the arrangement of boreholes and determining the concentration of the grouting material.
Thu, 12 December 2019
ARTICLE Download: 73| View: 61| Comments: 0 | doi:10.20944/preprints201912.0174.v1
Subject: Engineering, Industrial & Manufacturing Engineering Keywords: intrusion detection; ethernet/ip; industrial control networks
Online: 12 December 2019 (12:35:07 CET)
Standard Ethernet (IEEE 802.3 and the TCP/IP protocol suite) is gradually applied in industrial control system (ICS) with the development of information technology. It breaks the natural isolation of ICS, but contains no security mechanism. A modified intrusion detection system (IDS), which is strongly correlated to specific industrial scenario, is necessary for modern ICS. On the one hand, this paper outlines attack models, including infiltration attacks and our creative forging attack. On the other hand, we proposes a hierarchical IDS, which contains a traffic prediction model and an anomaly detection model. The traffic prediction model, which is based on autoregressive integrated moving average (ARIMA), can forecast the traffic of ICS network in the short term and precisely detect the infiltration attacks according to abnormal changes in traffic pattern. The anomaly detection model using one-class support vector machine (OCSVM) is able to detect malicious control instructions by analyzing the key field in EtherNet/IP packets. The experimental results show that the hierarchical IDS has an outstanding performance in detecting infiltration attacks and forging attack compared with other two innovative IDSs.
ARTICLE Download: 47| View: 46| Comments: 0 | doi:10.20944/preprints201912.0169.v1
Subject: Engineering, Civil Engineering Keywords: mortar mosaic; volubilis; characterization; mineralogical; testing; mechanical.
Online: 12 December 2019 (09:59:49 CET)
The objective of this study is to conduct a mineralogical and chemical characterization of the mortars Roman archaeological site of Volubilis to rebuild spare mortars for restoration. We take samples of mortar, broken tile palate garden, and pavement mosaic Falavius Germanus houses. The analysis by X-ray diffraction reveals the coarse mortar Flavius Germanus is made of quartz and calcite with feldspar and probably, mica and dolomite in small amounts. The binder end is formed calcite and quartz. However, the broken tile mortar is formed by coarse particles, clay base mixed with a binder phase dominated by calcite. These results allowed us to reformulate spare mortars for the restoration of damaged Roman mosaics. The mortars are made up by 63.6% of lime and 36.4% of sand(with 4.19% of large grain, 71, 04% of coarse sand, 24.22%, of fine sand and 0.55% fines parts).The performance of these mortars was tested by mechanical testing.
ARTICLE Download: 42| View: 74| Comments: 0 | doi:10.20944/preprints201912.0156.v1
Subject: Engineering, Mechanical Engineering Keywords: tensile strength; flexural strength; friction stir welding; microstructure; dissimilar aluminium alloys
Online: 12 December 2019 (01:58:14 CET)
Welding of dissimilar aluminium alloys has been a challenge for a long period until the discovery of the solid state welding technique called friction stir welding (FSW). The discovery of this technique encouraged different research interests revolving around the optimization of this technique. This involves the welding parameters optimization and this optimization is categorized into two classes i.e. similar alloys and dissimilar alloys. This paper reports about the mechanical properties of the friction stir welded dissimilar AA1050-H14 and AA5083-H111 joint. The main focus is to compare the mechanical properties of specimens extracted from different locations of the welds i.e. the beginning, middle and the end of the weld. The specimen extracted at the beginning of the weld showed low tensile properties compared to specimens extracted from different locations of the weld. There was no certain trend noted through the bending results. All three specimens showed dimpled fracture which is the characterization of the ductile fracture.
Wed, 11 December 2019
ARTICLE Download: 40| View: 84| Comments: 0 | doi:10.20944/preprints201912.0153.v1
Subject: Engineering, Civil Engineering Keywords: Masonry walls; Out-of-plane strengthening; FRP strips; Active strengthening techniques; Degree of Composite Action (DCA).
Online: 11 December 2019 (11:52:18 CET)
As is well known, the main contribution of the FRP strips to the strength of load-bearing walls is an improvement in the in-plane strength. This paper deals with the possibility of applying the FRP strips in way to modify the strengthening mechanism of the FRP reinforcing system, from an in-plane to an out-of-plane strengthening mechanism. In order to achieve this goal, a second reinforcement system – derived from the CAM system (Active Confinement of Masonry) – provides connections between the FRP strips placed on the opposite sides of the wall. This new strengthening technique – called the straps/strips technique – establishes a stiffness constraint that forces the opposing FRP strips to behave like two flanges of an FRP I-beam embedded in the wall. Consequently, the use of FRP strips also improves the flexural strength of the wall. The present paper briefly summarizes the results obtained in previous works with the straps/strips technique and proposes an improvement of this strengthening technique, based on some weak-points emerged in the early experimentations. The paper also shows the results of a further experimental test, performed with the improved straps/strips technique. Finally, the similarity between FRP strips with transversal connection and concrete wythes of a sandwich panel with flexible connectors leads to interpret the behavior of the ideal I-beam in terms of composite action established between the FRP strips. This paves the way for analytical modeling of the straps/strips technique.
ARTICLE Download: 66| View: 55| Comments: 0 | doi:10.20944/preprints201912.0148.v1
Subject: Engineering, Electrical & Electronic Engineering Keywords: Quality of Experience; Quality of Service; QoE evaluation video on demand; Quality of Service; QoS correlation; subjective testing
Online: 11 December 2019 (04:46:57 CET)
In addition to the traditional QoS metrics of delay, delay jitter, and packet loss probability (PLP), Quality of Experience (QoE) is now widely accepted as a numerical proxy for actual user experience. The literature has reported many mathematical mappings between QoE and QoS. These QoS parameters are measured by the network providers using sampling. There are some papers studying sampling errors in QoS measurements; however there is no account of propagation of these sampling errors to QoE evaluation. In this paper, we used industrially acquired measurements of PLP and jitter to evaluate the sampling errors and correlation in measurements. Focussing on Video-on-demand (VoD) applications, we use subjective testing and regression to map QoE metrics onto PLP and jitter. The resulting mathematical functions of QoE and theory of error propagation was used to evaluate the propagated error in QoE, and this error was represented as confidence interval. Using the guidelines of UK government for sampling, our results indicate that confidence intervals around estimated QoE in a busy hour can be between MOS=1 to MOS=5 at targeted operating point of QoS parameters. These results are a new perspective on QoE evaluation, and are of great significance to all organisations that need to estimate the QoE VoD applications precisely.
Tue, 10 December 2019
REVIEW Download: 85| View: 46| Comments: 0 | doi:10.20944/preprints201912.0145.v1
Subject: Engineering, Other Keywords: Requirement Change Management; Methodology; Change Management Process; Software System
Online: 10 December 2019 (16:41:40 CET)
During software development requirement gathering is an important phase. Requirements are the basis of software development. The success or failure of any software depends upon level of understanding developed in requirements. During software development requirements keeps on changing due to different reasons. Hence requirements are such a critical phase that leads to the total project failure. So, to understand the impacts and to identify the conflicts with existing requirements, it is important to manage and analyze the requirements well. Requirement change management is the interest of this paper. Different requirement change management techniques has been discussed in this paper and analyzed them well and finally conclude the results accordingly.
REVIEW Download: 34| View: 45| Comments: 0
Subject: Engineering, Other Keywords: Internet of Things(IoTs); Challenges; Test Strategies; Quality Assurance; Suggestion; Interoperability; Security
Online: 10 December 2019 (16:15:13 CET)
Immense challenges arise in the Quality Assurance area due to contemporary development in Internet of Things (IoT) technology. Current issues are mainly related to test coverage, test diversity, IoT Stability, Use of Cellular Networks in IoTs, IoT Devices updates, Security, Data Integration, and interoperability. In this paper, we present all those issues with suggestions for tackling those issues.
ARTICLE Download: 60| View: 64| Comments: 0 | doi:10.20944/preprints201912.0140.v1
Subject: Engineering, Marine Engineering Keywords: propeller; wageningen b-screw series; open-water characteristics; propeller efficiency map; danckwardt diagram; optimum propeller
Online: 10 December 2019 (15:57:55 CET)
Undoubtedly the Wageningen B-screw Series is the most widely used systematic propeller series. It is very popular to preselect propeller dimensions during the preliminary design stage, but often it is also used to merely select the final propeller. Over time the originally measured data sets were faired and scaled to a uniform Reynolds number (based on chord length and section advance speed) of 2·10⁶ to increase the reliability of the series. With the advent of the computer polynomials for the thrust and torque values were calculated from the available data sets. The measured data are typically presented in the well-known open-water curves of thrust and torque coefficients K_T and K_Q versus the advance coefficient J. Changing the presentation from open-water diagrams to efficiency maps reveals some unsuspected and surprising behaviours, such as multiple optima when optimizing for efficiency or even no optimum at all for certain conditions. These artefacts get more pronounced at higher pitch to diameter ratios and low blade numbers. The present work builds upon the paper presented by the author at the AMT'17 and smp'19 conferences and now includes the extended efficiency maps, as suggested by Danckwardt, for all propellers of the Wageningen B-screw Series.
REVIEW Download: 40| View: 45| Comments: 0 | doi:10.20944/preprints201912.0130.v1
Subject: Engineering, Other Keywords: risk management; safety critical systems; safety assessment; methodology
Online: 10 December 2019 (07:33:14 CET)
The complex systems that require safety are the Safety Critical Systems. Maintaining these systems is a big challenge. Now a days, safety is a very critical requirement for the latest systems. Safety critical systems must be safe. Different approaches to ensure quality and safety in safety critical systems has been discussed in this paper. A comparison is also conducted between these various approaches. Safety critical systems must remain more influential in future.
REVIEW Download: 47| View: 41| Comments: 0 | doi:10.20944/preprints201912.0128.v1
Subject: Engineering, Other Keywords: large scale systems; risk assessment; risk management techniques; risk mitigation
Online: 10 December 2019 (07:14:12 CET)
Risk assessment management have been a hot topic for the researchers since a very long time. Software risk management is an important part of project management as it contains the identification, analysis, estimation and monitoring of different risks present in the system. This helps developers in decision making while assessing the problems that could arise in the software systems. Risk management is very complex in large scale system as these systems have very complex development. The paper describes risk management techniques for large scale system. Furthermore we have provided a detailed comparative analysis of these techniques with commonly identified risks in software systems and have provided a systematic order for risk management process to ensure risk mitigation.
ARTICLE Download: 94| View: 116| Comments: 0 | doi:10.20944/preprints201912.0126.v1
Subject: Engineering, Electrical & Electronic Engineering Keywords: Internet of Things (IoT); wireless sensor networks; ContikiMAC; energy efficiency; duty-cycles; clear channel assessments (CCA); received signal strength indicator (RSSI)
Online: 10 December 2019 (05:15:21 CET)
The radio activity in Wireless Sensor Networks (WSN) and Internet of Things (IoT) applications are the most common reason for power consumption. However, recognizing and controlling the factors affecting radio activity can be valuable for managing node power. ContikiMAC is a low-power Radio Duty-Cycle protocol in Contiki OS that uses Clear Channel Assessments (CCA) to check radio status periodically. The time taken to check the radio in receive mode WakeUp, is one of the most important reasons for power consumption which in most the cases can lead to negative WakeUp in Radio Duty-Cycles and ContikiMAC especially. Here, we present a detailed analysis of idle listening time factors on the ContikiMAC. Then, we propose Light Weight CCA(LW-CCA) as an extension to ContikiMAC to reduce power consumption by reducing the radio check time in receive mode WakeUp’s, while maintaining up to 99% the Packet Delivery Rate (PDR). The simulation results show that the proposed method reduces significantly energy consumption in nodes compared to ContikiMAC and thus it helps maintain a high network performance.
Mon, 9 December 2019
ARTICLE Download: 39| View: 47| Comments: 0 | doi:10.20944/preprints201912.0122.v1
Subject: Engineering, Civil Engineering Keywords: emission eﬃciency; heat emission; setpoint variation; operative temperature; European Reference Room
Online: 9 December 2019 (10:44:18 CET)
Estimating heat emission losses of heating systems is an important task of energy efficiency assessments in buildings. To this aim, the present international standards contain tabulated values for different emitter and control system configurations, without however explaining how to compute the effect of increased setpoint temperatures on the system losses. Moreover, the effects of each component are treated as independent, while e.g. vertical stratification and temperature control of the system are cross-related. In this paper we attempt to fill this gap by proposing a calculation method to calculate the product category specific setpoint variations for space heating emitters, accounting for the overall heat balance in the enclosure and including the cross-correlations of each component as well. The emission losses of a heating system are computed using a temperature setpoint variation method that is imposed on annual energy calculations. This complements the procedure presented in the Standard EN15316-2, also providing the possibility to use product-specific values of setpoint variations instead of tabulated values. As the main finding of the study, the calculation process is defined for a European Reference Room, namely for a specific enclosure that allows an accurate and transparent evaluation of the total setpoint variation. The product-specific values of setpoint variations are calculated from measured vertical stratification and control parameters with an annual simulation model of the European Reference Room. The total setpoint variations were simulated for a set of heat emitters and controllers in order to quantify and compare the energy performance of a new and an old type building located in Strasbourg. We find that the total setpoint variation required to overcome emission losses is up to 2.00 °C in the old building and 1.20 °C in the new building, corresponding respectively to an increase in total heating energy usage of up to 22% and 20%.
REVIEW Download: 58| View: 55| Comments: 0 | doi:10.20944/preprints201912.0121.v1
Subject: Engineering, Other Keywords: triple constraints; augmented reality; Augmented reality-based learning systems; time; cost; scope; artificial intelligence; education
Online: 9 December 2019 (09:17:17 CET)
Over the last few decades there has been an exponential growth in IT, motivating IT professionals and scientists to explore new dimensions resulting in the advancement of artificial intelligence and its subcategories like computer vision, deep learning and augmented reality. AR is comparatively a new area which was initially explored for gaming but recently a lot of work has been done in education using AR. Most of this focuses on improving students understanding and motivation. Like any other project, the performance of an AR based project is determined by the customer satisfaction which is usually affected by the theory of triple constraints; cost, time and scope. many studies have shown that most of the projects are under development because they are unable to overcome these constraints and meet project objectives. We were unable to find any notable work done regarding project management for augmented reality systems and application. Therefore, in this paper, we propose a system for management of AR applications which mainly focuses on catering triple constraints to meet desired objectives. Each variable is further divided into subprocesses and by following these processes successful completion of the project can be achieved.
REVIEW Download: 173| View: 51| Comments: 0
Online: 9 December 2019 (07:42:25 CET)
In this paper we have discussed the importance of human resource management in project management. As a concept human resource management emerged in 1980 . It is very important to utilize resources effectively in any organization. Like triple constrains (cost, quality, scope) human resources are also considered as one of the most important factor for the success of any project. Management of human resources involve hiring experienced workers, giving appropriate training, acknowledgement about the significance of the project and the effective use of techniques and tools in order to get the project done productively with in time and budget. It becomes the responsibility of the project manager to effectively manage human resources as it is more challenging than managing other technical resources. In this paper we have also discussed the challenges that an organization faced during the management of the resources and use of some strategic human practices in order to overcome these challenges.
REVIEW Download: 61| View: 55| Comments: 0
Subject: Engineering, Other Keywords: SACDM; SOS; SQA; key factors software quality assurance; Scrum; stakeholder
Online: 9 December 2019 (07:37:30 CET)
The main moto of this study is to examine and study on behavior of Software Quality Assurance (SQA) issues of project stakeholders in a Scrum environment and their consequences. This inductive case study identifies SQA principles relevant to Meeting User Expectations. The Stakeholders in the Scrum project having lack of Concrete Guidance on Scrum’s SQA approaches, methods, and techniques. The insufficiency of concrete guidelines in Scrum needs a management squad to develop concepts that can include implementing practices from other methodologies and wisely modifying the system structure to incorporate the practices adopted, ensuring improvement in the processes, and creating a shared ownership environment. Through explaining the incompleteness of Agile approaches with special attention to the lack of concrete instructions in Scrum, the study uses techniques to customize literature and advocate for Scrum’s versatility. The study uses strategies to adapt literature and argue for Scrum’s simplicity by illustrating the incompleteness of Agile approaches with special attention to the lack of concrete instructions in Scrum methodology.
ARTICLE Download: 61| View: 69| Comments: 0
Subject: Engineering, Electrical & Electronic Engineering Keywords: Hyperjerk oscillator; Arduino board; multiple coexisting attractors; information security; image encryption
Online: 9 December 2019 (03:22:41 CET)
A lightweight image encryption algorithm based on chaos induction via a 5-dimensional hyperjerk oscillator (5DHO) is presented. First, the dynamics of our 5DHO network is investigated and shown to exhibit up to five coexisting hidden attractors in the state space that depend exclusively on the system’s initial values. Further, a simple implementation of the circuit was used to validate its ability to exhibit chaotic dynamical properties. Second, an Arduino UNO platform is used to confirm the usability of our oscillator in digital implementation of the system. Finally, an efficient image encryption application is executed using the proposed chaotic networks based on the use of permutation-substitution sequences. The superior qualities of the proposed strategy are traced to the dynamic set of keys used in the substitution process which heralds the generation of the final ciphered image. Based on the results obtained from the entropy analysis (7.9976), NPCR values (99.62), UACI tests (33.69) and encryption execution time for 512x512 images (0.1179 sec), the proposed algorithm is adjudged to be fast and robust to differential and statistical attacks relative to similar approaches.
Sun, 8 December 2019
ARTICLE Download: 54| View: 42| Comments: 0 | doi:10.20944/preprints201912.0102.v1
Subject: Engineering, Electrical & Electronic Engineering Keywords: forecasting of fuel demand; ship’s fuel consumption; data fitting; statistical quality measures; signal processing and analysis
Online: 8 December 2019 (17:05:03 CET)
Real data obtained from ship in operation are processed and analyzed in this paper. The intention was to provide software which would predict ship’s fuel consumption in some future time instant. It is showed that it is possible to develop such software based on numeric fitting of known data. In order to check how well the prediction of future fuel consumption is, we used only the first half of data for obtaining prediction curve. The second part of data was used to compare different prediction curves goodness. Hence, the presented research used actually a “real future data” and forecasted future data, which are used to numerically evaluate goodness of prediction. The research is of interest for companies logistics, to provide adequate fuel for fleet when and where actually needed. It is concluded that there are several prediction functions which satisfy used statistical quality measures.
ARTICLE Download: 128| View: 174| Comments: 0 | doi:10.20944/preprints201912.0101.v1
Subject: Engineering, Electrical & Electronic Engineering Keywords: Hyperloop; CFD; K-e model; Aerodynamics; Energy efﬁciency
Online: 8 December 2019 (16:32:24 CET)
Based on K-ε Standard Wall turbulence model (2-Equation) and Navier-Stokes (N-S) equations defined for incompressible fluids, fluid flow behaviour around hyperloop pods in an evacuated tube was simulated using ANSYS fluent solver assuming steady state and two dimensional conditions. In this research, to develop the case studies, using combination of different head and tail shape profile, four kind of hyperloop pods were developed with the aid of SolidWorks. These four pods have been investigated for their aerodynamic behaviour as four different case scenarios. The results of simulation depicts that an atmospheric pressure of 100 Pa with blockage ratio of 0.36 in tube provides the best possible aerodynamic behaviour for the designed hyperloop pod models. This research finds that overall aerodynamic behaviour of hyperloop pods can be varied by changing the head and tail shape profile of pods and a particular combination of head and tail shape profile can provide optimally best aerodynamic capabilities. Thus, this research paper provides a novel method of obtaining best aerodynamic capabilities in hyperloop pods by designing head profile optimally in combination with tail profile. This outcome will provide major contribution towards the development of hyperloop pods in future with better aerodynamic behaviour resulting in lesser electrical energy required to propel the hyperloop pods in evacuated tube.
ARTICLE Download: 50| View: 75| Comments: 0 | doi:10.20944/preprints201912.0098.v1
Subject: Engineering, Automotive Engineering Keywords: child seats; car accidents; car crash analyses; children safety
Online: 8 December 2019 (15:45:04 CET)
The study presents a comparison of the common Child Restraint Systems (CRS) which reduces the value of dynamic loads affecting the child's body during car accidents. The analyzed systems were: child seats, Combi Booster Seats, and straps adjusting vehicle seat belts to children's sizes. The effectiveness of the analyzed devices was assessed on the basis of experimental tests carried out in the accredited laboratory approving the Child Restraint Systems. The tests were carried out accordingly to the new Regulation No. 129 UN / ECE. Whether the tested devices meet the guidelines of the new Regulations No. 129 despite approval in accordance with Regulation No. 44. Based on the research result, better safety parameters of some new solutions dedicated to children's safety could be observed. The final results show that there is still space for improving the safety of young vehicle passengers.
Sat, 7 December 2019
ARTICLE Download: 40| View: 42| Comments: 0
Subject: Engineering, Electrical & Electronic Engineering Keywords: inter-vehicle communication; content-centric network; cache miss
Online: 7 December 2019 (15:45:30 CET)
Recently, inter-vehicle communication, which helps to avoid collision accidents (by driving safety support system) and facilitate self-driving (by dissemination of road and traffic information), has attracted much attention. In this paper, in order to efficiently collect road / traffic information in the request / response manner, first a basic method, Content-centric network (CCN) for Vehicular network (CV), is proposed, which applies CCN cache function to inter-vehicle communication. Content naming and routing, which take vehicle mobility into account, are investigated. On this basis, the CV method is extended (named as ECV) to avoid the cache miss problem caused by vehicle movement, and is further enhanced (named as ECV+) to more efficiently exploit cache buffer in vehicles, caching content according to a probability decided by channel usage rate. Extensive evaluations on network simulator Scenargie, with realistic open street map, confirm that the CV method and its extensions (ECV, ECV+) effectively reduce the average number of hops of data packets (by up to 47%, 63%, 83% respectively) and greatly improve the content acquisition success rate (by up to 356%, 444%, 689%, respectively), compared to the method without cache mechanism.
ARTICLE Download: 60| View: 63| Comments: 0 | doi:10.20944/preprints201912.0091.v1
Subject: Engineering, Mechanical Engineering Keywords: cell-based smoothed finite element method; quadratic triangular element; linear smoothing function; hyperelasticity
Online: 7 December 2019 (01:51:23 CET)
This work presents a linear smoothing scheme over high-order triangular elements in the framework of a cell-based strain smoothed finite element method for two-dimensional nonlinear problems. The main idea behind the proposed linear smoothing scheme for strain-smoothed finite element method (S-FEM) is no subdivision of finite element cells to sub-cells while the classical S-FEM needs sub-cells. Since the linear smoothing function is employed, S-FEM is able to use quadratic triangular or quadrilateral elements. The modified smoothed matrix obtained node-wise is evaluated. In the same manner with the computation of the strain-displacement matrix, the smoothed stiffness matrix and deformation graident are obtained over smoothing domains. A series of benchmark tests are investigated to demonstrate validity and stability of the proposed scheme. The validity and accuracy are confirmed by comparing the obtained numerical results with the standard FEM using 2nd-order triangular element and the exact solutions.
Fri, 6 December 2019
REVIEW Download: 70| View: 71| Comments: 0 | doi:10.20944/preprints201912.0082.v1
Subject: Engineering, Other Keywords: noise; noise induced hearing loss; noise apps; weather stressors; psychological stressors; tractor safety; seatbelt use; dust; air quality
Online: 6 December 2019 (11:37:43 CET)
There are numerous hazards found on the farms. Most of them are ignored, which might cause the farmer to pay later in terms of his ill health, potential injuries or death. The current article discusses some of the common issues such as dust and air quality concerns; environmental (weather) stressors and psychological stressors; noise and hearing protection; and tractor safety and seatbelt use. And finally, the recommendations to overcome the hazards are discussed.
ARTICLE Download: 35| View: 35| Comments: 0
Online: 6 December 2019 (11:29:09 CET)
Directional Modulation (DM) technique, as an emerging promising approach to secure wireless communications, has been attracting increasing attention for its unique characteristic in the past decade. The baseband signal is synthesized at the antenna level for maintaining the standard constellation format along the prescribed direction(s) while simultaneously distorting the signal constellations in other undesired directions. In this paper, we present a novel DM signal synthesis method based on phased array using a hybrid genetic algorithm (GA) and particle swarm optimization (PSO) algorithm, which takes advantages of both GA and PSO algorithm. Then, the bit error rate of the proposed method is analyzed and simulated. Simulation results are presented to verify that the proposed DM signal have a narrower information beam-width. Therefore, it can offer a better physical layer security (PLS) performance compared with the conventional directional modulation signal.
ARTICLE Download: 87| View: 63| Comments: 0
Subject: Engineering, Automotive Engineering Keywords: software defect prediction; machine learning approach; integrated approach; Deep Forest
Online: 6 December 2019 (04:25:21 CET)
Accurate prediction of defects in software components plays a vital role in administrating the quality of the quality and efficiency of the system to be developed. So we have written a systematic literature review in order to evaluate the four main defect prediction techniques. Defect prediction paves way for the testers to find bugs and modify them in order to achieve input to output conformance. In this paper we have discussed the open issues in predicting software defects and have provided with a detailed analyzation of different methods including Machine Learning, Integrated Approach, Cross-Project and Deep Forest algorithm in order to prevent these flaws. However, it is almost impossible to rule which method is better than the other so every technique can be analyzed separately and the best technique according to the problem at hand can be used or can be altered to create hybrid technique suitable for the cause.
Thu, 5 December 2019
ARTICLE Download: 43| View: 48| Comments: 1 | doi:10.20944/preprints201910.0368.v2
Subject: Engineering, Electrical & Electronic Engineering Keywords: directional modulation; physical layer security; polarization sensitive array; multi-beam
Online: 5 December 2019 (11:59:29 CET)
Directional modulation (DM), as an emerging promising physical layer security (PLS) technique at the transmitter side with the help of an antenna array, has developed rapidly over decades. In this study, a DM technique using a polarization sensitive array (PSA) to produce the modulation with different polarization states (PSs) at different directions is investigated. A PSA, as a vector sensor, can be employed for more effective DM for an additional degree of freedom (DOF) provided in the polarization domain. The polarization information can be exploited to transmit different data streams simultaneously at the same directions, same frequency, but with different PSs in the desired directions to increase the channel capacity, and with random PSs off the desired directions to enhance PLS. The proposed method has the capability of concurrently projecting independent signals into different speciﬁed spatial directions while simultaneously distorting signal constellation in all other directions. The symbol error rate (SER), secrecy rate, and the robustness of the proposed DM scheme are analyzed. Design examples for single- and multi-beam DM systems are also presented. Simulations corroborate that 1) the proposed method is more effective for PLS; 2) the proposed DM scheme is more power-efﬁcient than the traditional artiﬁcial noise aided DM schemes; and 3) the channel capacity is signiﬁcantly improved compared with conventional scalar antenna arrays.
REVIEW Download: 75| View: 62| Comments: 0 | doi:10.20944/preprints201912.0068.v1
Subject: Engineering, Other Keywords: Analytical Hierarchy process; AHP; fuzzy; project management; risk prioritization; critical success factors; ETL; MCDM; TOPSIS
Online: 5 December 2019 (11:30:08 CET)
Today project management in every field of life is prerequisite for the success of project by increasing quality reduces cost and schedule. But selecting tools and techniques to achieve our objectives and implement our plan fully is very difficult task because choice creates complexity. So, we discuss AHP to make decision simple. Ranking critical success factor, cloud computing services, risk prioritization, selection of right ETL software and many other systems AHP plays its important role. For the improvement of today’s complex systems it is very important to prioritize and select projects to remove the root cause of the problem. To attain the right selection of construction equipment for carrying out schedule tasks with high efficiency, production and financial capability is the main purpose of procurement of construction equipment process. Certain conflicts can occur due to the construction of UML models in a collaborative way. AHP is used to remove these conflicts and for establishing and evaluating modelers judgments. Nowadays it is very important and critical decision to choose the best option from multiple alternatives for a successful career after passing 12th standard and also it affects our future. “AHP and TOPSIS” methods are used for this purpose. In this paper, an “AHP and Fuzzy AHP” based hierarchical trust model has been used to rate the service providers and their various plans for infrastructure as a service.
REVIEW Download: 67| View: 62| Comments: 0 | doi:10.20944/preprints201912.0065.v1
Subject: Engineering, Other Keywords: augmented reality; mixed reality; learning applications; SLR; AR evaluation; research methods; AR in education
Online: 5 December 2019 (08:54:35 CET)
With the advancement in AR technology, more education-based applications are being developed using Augmented Reality, which has revolutionized the learning experience. However, in order to determine the application’s impact on student’s motivation, performance and their communication with the lecturer, various studies are conducted. These studies use one of the three research methodologies for data analysis and evaluation. In this systematic review, we have analyzed various research methodologies for system evaluation of the AR learning applications and recorded the student response toward the system. Also, we checked which methodology is preferred by researchers and why. A total number of 25 studies were analyzed which were published during the year of 2015 and 2019. The results indicate that most popular research technique is mixed methodology as it combines both qualitative and quantitative techniques. The purpose of this review is to offer new insights to researchers and provide them with advice about evaluation of AR applications and which tool or technique is more effective.
ARTICLE Download: 75| View: 69| Comments: 0 | doi:10.20944/preprints201912.0063.v1
Subject: Engineering, Other Keywords: Software Quality Metrics; closed source software; open source software; Kahane’s Approach; UCP (Use Case Points) model and William’s Models
Online: 5 December 2019 (08:37:56 CET)
The complexity of software is increasing day by day due to the increase in the size of the projects being developed. For better planning and management of large software projects, estimation of software quality is important. During the development processes, complexity metrics are used for the indication of the attributes/characteristics of the quality software. There are many studies about the effect of the complexity of the software on the cost and quality. In this study, we discussed the effects of software complexity on the quality attributes of the software for open source and closed source software. Though, the quality metrics for open and closed source software are not distinct from each other. In this paper, we comparatively analyzed the impact of complexity metrics on open source and private software. We also presented various models for the management of the project complexity such as William’s Model, Stacey’s Agreement and Certainty matrix, Kahane’s Approach and UCP Model. Quality metrics here refer to the standards for the measurement of the quality of software which contains certain attributes or characteristics of the software that are related to the quality of the software. Certain quality attributes addressed in this study are Usability, Reliability, Security, Portability, Maintainability, Efficiency, Cost, Standards and Availability, etc. Both Open source and Closed source software are evaluated on the basis of these quality attributes. This study also recommended future approaches to manage the quality of project Open source and Closed source software and specify which one of them is mostly used in the industry.
REVIEW Download: 77| View: 72| Comments: 0 | doi:10.20944/preprints201912.0062.v1
Subject: Engineering, Other Keywords: six sigma; lean six sigma; DMAIC; DMADV; agile; defect per million opportunities(DPMO); SPC
Online: 5 December 2019 (04:22:42 CET)
The main purpose of this research is to use “DMAIC” and “DMADV” framework of six sigma to reduce cost of projects, increase yields, improve performance and reduce defects. This study conclude that the sigma level of cement bag production in four production lines is “4.7 DPMO” values of 710 and the possibility of defects per unit of 11 possibilities this situation was handled by using six sigma. Any business or industry run only to satisfy customer and increase their profits, this can be attained as development of quality product..For the ranking of newly established universities the certification of those institutes is very important and also a critical process. For this process we used Lean six sigma approach that can identify the wastes that affect this process.Six sigma can be applied to any work field such as education, power optimization and other types of industries Six sigma “DMAIC” approach is also used for the testing of EDA tools that occurs due to the complex coding or configurations, flows and platforms they support. To improve the process quality of SDLC it’s necessary to remove the defects of system in advance along with thorough valuation of size and it also makes project accordant with real time environment
REVIEW Download: 51| View: 55| Comments: 0 | doi:10.20944/preprints201912.0061.v1
Subject: Engineering, Other Keywords: scope creep; software engineering; software project management; work breakdown structure; agile method; traditional methodology; functional point analysis; stakeholders
Online: 5 December 2019 (04:20:06 CET)
Scope, time, and cost permanently effects each other and most of Information Technology projects fails due to these three factors. Scope shifting mostly occur due to time and cost. At project start, lack of understanding of project and product scope is focal involvement that leads to unsuccessful projects. Complete software scope definition determines quality of project. Defining the customer requirement and the definite scope of project has key role for implementation of project management. The complications originates when systems are developed from impractical expectations and misunderstanding requirements. These problems are cause of many changes, occurs in system development and leads to poor scope management. Scope creep is one of the momentous prompting parameter on the success of project. The failure in manage scope creep leads for 80 percent of software projects failure. However, using agile approach the impact of scope creep on projects become insignificant. A correctly distinct scope tends us to develop a quality product, within identified plans and decided cost to the stake-holders.
Wed, 4 December 2019
ARTICLE Download: 65| View: 80| Comments: 0 | doi:10.20944/preprints201912.0055.v1
Subject: Engineering, Biomedical & Chemical Engineering Keywords: dielectrophoresis; porous media; filtration; ac electrokinetics
Online: 4 December 2019 (12:54:38 CET)
State-of-the-art dielectrophoretic (DEP) separation techniques provide unique properties to separate particles from a liquid or particles with different properties such as material, morphology or size from each other. However, such separators do not operate at throughput that is sufficient for a vast fraction of separation tasks. The reason for this limitation is that, in order to move particles by dielectrophoresis, high electric field gradients to drive the separation are required. Conventionally, those gradients are generated by electrode microstructures that limit the maximum channel size. Here, we investigate DEP filtration, a technique that uses open porous microstructures instead of microfluidic devices to easily increase the filter cross section and therefore also the processable throughput by several orders of magnitude. Previously, we already separated baker’s yeast by DEP filtration in open porous ceramic structures. Now, we give a more elaborate experimental study about DEP filtration in these open porous structures and separate model particles, that are an order of magnitude smaller (500 nm, polystyrene), from aqueous suspensions. Almost 100% separation at flow rates of up to 9 mL min-1 was achieved while the majority of the trapped particles could be recovered. We show how particle separation depends on key parameters (voltage, throughput, filter structure size). Further, we work towards selective particle separation and show that particle separation is very dependent on the particle polarizability: This creates the possibility to adjust selectivity by changing the electrical conductivity of the suspension around that of the particle. This study highlights the unique qualities of dielectrophoretic filtration enabling switchable, selective, and scalable particle separation to solve existing problems such as cell separation or precious metal recovery.
REVIEW Download: 142| View: 105| Comments: 0 | doi:10.20944/preprints201912.0048.v1
Subject: Engineering, Energy & Fuel Technology Keywords: thermal desalination; Reverse Osmosis; advanced heat transfer fluids; sustainable desalination practices; integrated solar thermal nanofluids based desalination
Online: 4 December 2019 (11:31:44 CET)
Desalination accounts for 1% of the total global water consumption and is an energy-intensive process, with the majority of operational expenses attributed to energy consumption. Moreover, at present, a significant portion of the power comes from traditional fossil fuel-fired power plants and the greenhouse gas emissions associated with power production along with concentrated brine discharge from the process, pose a severe threat to the environment. Due to the dramatic impact of climate change, there is a major opportunity to develop sustainable desalination processes to combat the issues of brine discharge, greenhouse gas emissions along with a reduction in energy consumption per unit of freshwater produced. Nanotechnology can play a vital role to achieve specific energy consumption reduction as nanofluids application increases the overall heat transfer coefficient enabling the production of more water for the same size desalination plant. Furthermore, concentrated brine discharge has a negative impact on the marine ecosystems, and hence, this problem must also be solved to support the objective of sustainable desalination. Several studies have been carried out in the past several years in the field of nanotechnology applications for desalination, brine treatment and the role of renewable energy in desalination. This paper aims to review the major advances in this field of nanotechnology for desalination. Furthermore, a hypothesis for developing an integrated solar thermal and nanofluid sustainable desalination system, based on the cyclic economy model is proposed.
Tue, 3 December 2019
ARTICLE Download: 45| View: 91| Comments: 0
Subject: Engineering, Automotive Engineering Keywords: software project managemnet; complexity factors; PMBOX; paradigms of complexity; knowledge areas
Online: 3 December 2019 (12:00:18 CET)
Software project complexity increases day by day because the software engineering products is being used in the solution of more technically difficult problem and the size of project continuous to grow. The increase complexity causes to high numbers of software project failures in term of time, cost and quality. The main question regarding to this problem is how to handle or cope with this complexity. There is no single way to handle this, software engineer uses different perspective to handle complexity without affecting the overall project performance. A management perspective recognizes that the success of complex project requires good project management. A technically perspective reveals new paradigms for software development i.e.; object oriented and formal methods etc. and software engineer also look for automation perspective in order to reduce the complexity issues. In this paper we will find out the main software project complexity factors by focusing on the management aspects of software project development and also the problems of managing complexity in software engineering products from these different perspectives. The paper is divided in three main sections; paradigms of software development, project management in term of time, cost and quality and third one is automated support that includes methods and tools used to manage the complexity.
ARTICLE Download: 63| View: 55| Comments: 0 | doi:10.20944/preprints201912.0025.v1
Subject: Engineering, Electrical & Electronic Engineering Keywords: f-factors; energy storage; investments in electricity systems; mathematical optimization; security of supply
Online: 3 December 2019 (11:52:19 CET)
The ongoing electrification of the heat and transport sectors is expected to lead to a substantial increase in peak electricity demand over the coming decades, which may drive significant investment in network reinforcement in order to maintain a secure supply of electricity to consumers. The traditional way of security provision has been based on conventional investments such as the upgrade of the capacity of electricity transmission or distribution lines. However, the energy storage technology can also provide security of supply, thereby constituting a cost-efficient alternative to expensive conventional reinforcements. In this context, the current paper presents a methodology for the economic quantification of the security contribution of energy storage. This methodology makes use of mathematical optimization for the calculation of the F-factor metric, which reflects the optimal amount of peak demand reduction as compared to the power capability of the energy storage asset. In this context, a case study is presented in which the security contribution of energy storage is analyzed as a function of its power capability, energy capacity and efficiency as well as of characteristics of load patterns.
ARTICLE Download: 58| View: 82| Comments: 0 | doi:10.20944/preprints201912.0023.v1
Subject: Engineering, Biomedical & Chemical Engineering Keywords: dielectrophoresis; microparticles; chromatography; separation; polarizability
Online: 3 December 2019 (11:30:11 CET)
The separation of microparticles with respect to different properties such as size and material is a research field of great interest. Dielectrophoresis, a phenomenon which is capable of addressing multiple particle properties at once, can be used to perform a chromatographic separation. However, the selectivity of current dielectrophoretic particle chromatography (DPC) techniques is limited. Here we show a new approach for DPC based on differences in the dielectrophoretic mobilities and the crossover frequencies of polystyrene particles. Both differences are addressed by modulating the frequency of the electric field to generate positive and negative dielectrophoretic movement to achieve multiple trap and release cycles of the particles. A chromatographic separation of different particle sizes revealed a voltage dependency of this method. Additionally, we showed the frequency bandwidth influence on separation using one example. The DPC method developed was tested with model particles but offers possibilities to separate a broad range of plastic and metal microparticles or cells and to overcome currently existing limitations in selectivity.
REVIEW Download: 115| View: 138| Comments: 0 | doi:10.20944/preprints201912.0016.v1
Subject: Engineering, Industrial & Manufacturing Engineering Keywords: artificial intelligence; machine learning; systematic literature review; applications; industry 4.0
Online: 3 December 2019 (05:34:17 CET)
The history of Artificial Intelligence (AI) development dates to the 40s. The researchers showed strong expectations until the 70s, when they began to encounter serious difficulties and investments were greatly, reduced. With the introduction of the Industry 4.0, one of the techniques adopted for AI implementation is Machine Learning (ML) that focuses on the machines ability to receive data series and learn on their own. Given the considerable importance of the subject, researchers have completed many studies on ML to ensure that machines are able to replace or relieve human tasks. This research aims to analyze, systematically, the literature on several aspects, including publication year, authors, scientific sector, country, institution, keywords. Analyzing existing literature on AI is a necessary stage to recommend policy on the matter. The analysis has been done using Web of Science and SCOPUS database. Furthermore, UCINET and NVivo 12 software have been used to complete them. Literature review on ML and AI empirical studies published in the last century was carried out to highlight the evolution of the topic before and after Industry 4.0 introduction, from 1999 to now. Eighty-two articles were reviewed and classified. A first interesting result is the greater number of works published by USA and the increasing interest after the birth of Industry 4.0.
ARTICLE Download: 72| View: 143| Comments: 0 | doi:10.20944/preprints201912.0014.v1
Subject: Engineering, Civil Engineering Keywords: Discrete Element Method (DEM); Cell Method (CM); multiscale modeling; periodic composite materials; nonlocality
Online: 3 December 2019 (03:47:25 CET)
This paper deals with a DEM (Discrete Element Method) approach of the Cell Method (CM), useful for providing a multiscale modeling of composite materials. The new numerical model, called DECM, combines the main features of both the DEM and the CM. In particular, it offers the same degree of detail as the CM, on the microscale, and manages the discrete elements individually such as the DEM—allowing finite displacements and rotations—on the macroscale. Moreover, the DECM is able to activate crack propagation until complete detachment and automatically recognizes new contacts. Unlike other DEM approaches for modeling failure mechanisms in a continuum, the DECM does not require prior knowledge of the failure position. Furthermore, the DECM solves the problems in the space domain directly. Therefore, it does not require any dynamic relaxation techniques to obtain the static solution. For the sake of example, the paper shows the results offered by the DECM for axial and shear loading of a composite two-dimensional domain with periodic round inclusions. The paper also offers some insights into how the inclusions modify the stress field into composite continua.
Mon, 2 December 2019
ARTICLE Download: 87| View: 81| Comments: 0 | doi:10.20944/preprints201912.0003.v1
Subject: Engineering, Electrical & Electronic Engineering Keywords: physical layer security (PLS); cooperative relay transmission; non-orthogonal multiple access (NOMA); fuzzy logic; feed forward neural networks (FFNN); secrecy capacity
Online: 2 December 2019 (04:30:17 CET)
Cooperative non-orthogonal multi access communication is a promising paradigm for the future wireless networks because of its advantages in terms of energy efficiency, wider coverage and interference mitigating. In this paper, we study the secrecy performance of a downlink cooperative non-orthogonal multi access (NOMA) communication system under the presence of an eavesdropper node. Smart node selection based on feed forward neural networks (FFNN) is proposed in order to improve the physical layer security (PLS) of a cooperative NOMA network. The selected cooperative relay node is employed to enhance the channel capacity of the legal users, where the selected cooperative jammer is employed to degrade the capacity of the wiretapped channel. Simulations of the secrecy performance metric namely the secrecy capacity ($C_S$) are presented and compared with the conventional technique based on fuzzy logic node selection technique. Based on our simulations and discussions the proposed technique outperforms the existing technique in term the of secrecy performance.
ARTICLE Download: 96| View: 65| Comments: 0 | doi:10.20944/preprints201912.0001.v1
Subject: Engineering, Mechanical Engineering Keywords: gas turbine engine; performance model; gas path analysis; robust estimation; identification; fuzzy set; membership function
Online: 2 December 2019 (02:54:00 CET)
Gas Path Analysis and matching turbine engine models to experimental data are inverse problems of mathematical modelling which are characterized by parametric uncertainty. This results from the fact that the number of measured parameters is significantly lower than the number of components’ performance parameters needed to describe the real engine. In these conditions, even small measurement errors can result in a high variation of results, and obtained efficiency, loss factors etc. can appear out of the physical range. The current methods of engine model identification have developed considerably to provide stable, precise and physically adequate solutions. Presented in this work is an estimation method of engine components’ parameters based on multi-criteria identification which provides stable estimations of parameters and their confidence intervals with the known measurement errors. A priori information about the engine, its parameters and performance is used directly in the regularised identification procedure. The mathematical basis for this approach is the fuzzy sets theory. Forming objective functions and scalar convolutions synthesis of these functions is used to estimate gas-path components’ parameters. A comparison of the proposed approach with traditional methods showed that its main advantage is high stability of estimation in the parametric uncertainty conditions. Regularization reduces scattering, excludes incorrect solutions which do not correspond to a priori assumptions, and also helps to implement the Gas Path Analysis at the limited number of measured parameters. The method can be used for matching thermodynamic models to experimental data, Gas Path Analysis and also adapting dynamic models for the needs of the engine control system.
Sat, 30 November 2019
ARTICLE Download: 59| View: 56| Comments: 0
Subject: Engineering, Civil Engineering Keywords: v-shaped bridge columns; bridge junctions; shape memory alloy; seismic separator; seismic performance
Online: 30 November 2019 (14:54:54 CET)
In recent decades, widespread damage to structures due to destructive earthquakes has encouraged researchers to use seismic control systems. One of the most important structures is bridges, which should maintain their service after severe earthquakes. One of the ways to control the bridge is to isolation the deck from the substructure, which results in high displacements at different points in the bridge and the residual displacements within the separator itself, thus requiring repair and replacement of these systems after severe earthquakes. Therefore, the use of new seismic separation systems on bridges has always been important. The purpose of this project is to utilize a new memory-shaped seismic separator system to investigate the seismic performance of v-shaped column bridges , in which case the effect of earthquake orientation and its effects on responses the earthquake will also be assessed. Due to the ever-increasing advances in various intelligent materials, such as shape memory alloys, and their unique capacities, such as back-centering, and high fatigue and corrosion resistance, in this study, these materials have been used as a complementary component along with lead core separators. The shape memory alloy has been used as 4 vertical rods that connect two separating parts to each other and in this research the diameter and location of these rods will be calculated using optimization algorithm in Matlab software.
ARTICLE Download: 60| View: 53| Comments: 0 | doi:10.20944/preprints201911.0397.v1
Subject: Engineering, Energy & Fuel Technology Keywords: methane emissions; coal seam mining; gas engines; greenhouse gas
Online: 30 November 2019 (14:27:52 CET)
During the extraction of hard coal in Polish conditions, methane is emitted, which is referred to as mine gas. As a result of the desorption of methane, a greenhouse gas is released from coal seams. In order to reduce atmospheric emissions, methane from coal seams is captured by a methane drainage system. On the other hand, methane, which has been separated into underground mining excavations, is discharged into the atmosphere with a stream of ventilation air. For many years, Polish hard coal mines have been capturing methane to ensure the safety of the crew and the continuity of mining operations. As a greenhouse gas, methane has a significant potential, as it is more effective at absorbing and re-emitting radiation than carbon dioxide. The increase in the amount of methane in the atmosphere is a significant factor influencing global warming, however, it is not as strong as the increase in carbon dioxide. Therefore, in Polish mines, the methane-air mixture captured in the methane drainage system is not emitted to the atmosphere, but burned as fuel in systems, including cogeneration systems, to generate electricity, heat and cold. However, in order for such use to be possible, the methane-air mixture must meet appropriate quality and quantity requirements. The article presents an analysis of changes in selected parameters of the captured methane-air mixture from one of the hard coal mines in the Upper Silesian Coal Basin in Poland. The paper analyses the changes in concentration and size of the captured methane stream through the methane capturing system. The gas captured by the methane drainage system, as an energy source, can be used in cogeneration, when the methane concentration is greater than 40%. Considering the variability of CH4 concentration in the captured mixture, it was also indicated which pure methane stream must be added to the gas mixture in order for this gas to be used as a fuel for gas engines. The balance of power of produced electric energy in gas engines is presented. Possible solutions ensuring constant concentration of the captured methane-air mixture are also presented.
ARTICLE Download: 102| View: 73| Comments: 0
Subject: Engineering, Energy & Fuel Technology Keywords: heterogenous catalyst; biodiesel; agrowaste; microwave; optimization; transesterification
Online: 30 November 2019 (12:10:38 CET)
Application of solid catalysts synthesized from agricultural wastes provides an environmentally benign and low-cost process route to the synthesis of biodiesel. An ash containing equal mixture of cocoa pod husk, plantain peel and kola nut pod husk ashes (CPK) which was obtained by open combustion of each biomass in air and calcined at 500 oC for 4 h. The calcined CPK ash was characterized to determine its catalytic potential. Two-level transesterification technique was used to synthesize biodiesel using the developed catalyst. The process parameters involved were optimized for the microwave-aided transesterification of a blend of honne, rubber seed and neem oils in volumetric ratio 20:20:60, respectively. The study showed that ash derived from combination of various biomass wastes provides a catalyst which consists all necessary catalytic ingredients in their relative abundance. The calcined CPK consists of 47.67% of potassium, 5.56% calcium and 4.21% magnesium attesting to its heterogenous status. The physisorption isotherms reveals that it was dominantly mesoporous in structure made up of nanoparticles. Maximum of 98.45 wt.% biodiesel was obtained through MeOH:oil blend of 12:1, CPK concentration of 1.158 wt.% and reaction time of 6 min under microwave irradiation. Quality of the synthesized biodiesel satisfied the requirements stipulated by standard specifications. Thus, this work demonstrates that blend of agrowastes and mixture of non-edible oils could be used to synthesize quality and sustainable biodiesel that can replace fossil diesel.
ARTICLE Download: 57| View: 42| Comments: 0
Subject: Engineering, Electrical & Electronic Engineering Keywords: electric vehicles charging navigation system; charging path; road transportation network; distribution network; real-time electricity price
Online: 30 November 2019 (09:39:27 CET)
Aiming at the current optimization problem of electric vehicle charging path planning, a charging path optimization strategy for electric vehicles under the "Traffic-Price-Distribution" mode is proposed. This strategy builds an electric vehicle charging and navigation system based on road traffic network model, real-time electricity price model and distribution network model. Based on Dijkstra shortest path algorithm and Monte Carlo time-space prediction method, the goal is to minimize the charging cost of electric vehicles. Optimal charging path. The simulation results of MATLAB and MATPOWER show that the electric vehicle charging path optimization strategy can better solve the local traffic congestion problem and improve the safety and stability of the distribution network on the basic of fully considering the convenience of electric vehicle charging.
Fri, 29 November 2019
ARTICLE Download: 203| View: 245| Comments: 0 | doi:10.20944/preprints201911.0377.v1
Subject: Engineering, Construction Keywords: ultra-high-performance fiber-reinforced concrete (UHPFRC); mechanical properties; extrusion; 3D concrete printing (3DCP)
Online: 29 November 2019 (10:45:46 CET)
This paper presents the systematic development and performance characterization of a non-proprietary 3D-printable ultra-high-performance fiber-reinforced concrete (UHPFRC) for digital construction. Several fresh and hardened properties of the developed 3D-printable UHPFRC matrix (without fiber) and composite (with 2% volume fraction of steel fibers) were evaluated and compared to that of conventionally mold-cast UHPFRC. Additionally, the effects of testing direction on the compressive and flexural strengths of the printed UHPFRC were investigated. The fresh properties of the UHPFRC developed in this study satisfied the criteria for extrudability, buildability, and shape-retention-ability, which are relevant for ensuring printability. The printed UHPFRC exhibited superior flexural performance to the mold-cast UHPFRC due to alignment of the short fibers in the printing direction. The high compressive and flexural strengths, along with the deflection-hardening behavior, of the developed UHPFRC can enable the production of thin 3D-printed components with significant reduction or complete elimination of conventional steel bars.
ARTICLE Download: 47| View: 56| Comments: 0 | doi:10.20944/preprints201911.0374.v1
Subject: Engineering, Mechanical Engineering Keywords: finishing; plastic working; machining; nickel matrix composite; coatings
Online: 29 November 2019 (09:43:58 CET)
Metal matrix composite are used in such fields of technology, such as: aerospace, electronics, energy, industry, defense, automotive, aviation, shipbuilding, and more. Composite coatings of ceramic - metals is used primarily to enhance the durability of machine parts. Therefore, new materials are permanently looked for, what has resulted in the past in development of composite materials. The coatings dispersed are consisting of metallic matrix (metals and their alloys) and small non-metallic particles. The deposition of ceramic particles simultaneously with metallic matrix leads often to composite coatings possessing properties much better than those of metallic coating. The nickel and less often, other iron group elements are usually used as a matrix and Al2O3 as tough particles. The welding technology of applying alloy and composite coatings is widely used. The technology of infrasound thermal spraying of metal matrix composite coatings was presented. It is a simple technology and a very useful one in ship machinery regeneration during the cruise craft (e.g. internal combustion engines, torque pumps, separators). The metal matrix composite coatings must undergo finishing due to high surface roughness after application. In the article to used finishing by plastic working and machining of coatings nickel matrix composite was proposed.
ARTICLE Download: 61| View: 82| Comments: 0 | doi:10.20944/preprints201911.0373.v1
Subject: Engineering, Energy & Fuel Technology Keywords: jet fuel efficiency; environment; idle capacity; panel data
Online: 29 November 2019 (09:41:35 CET)
Since World War I, the commercial aviation industry has seen many improvements that now allow people and goods to reach the other side of the world in few hours, consuming much less fuel than in recent decades. Improvements in cargo capacity and energy efficiency were significant and, in this scenario, commercial airlines were able to thrive and bring great benefits to world economy. However, this sector is facing environmental challenges due to the intensive use of aviation fuel. Brazil is one of the largest domestic air passenger markets in the world and still has great growth potential, considering its economic potential and territorial dimensions: roughly the same size as the US and twice the size of the European Union. This paper discusses partial productivity of jet fuel in Brazilian domestic aviation and proposes an econometric method to support public regulators and airlines decisions. The proposed model uses variables such as aircraft size, route characteristics and idle flight capacity in a panel data analysis. The results show that reducing idle capacity is one of the best ways to achieve better short-term fuel efficiency and therefore will reduce environmental impacts and have positive economic effects on commercial air transport activities.