ARTICLE | doi:10.20944/preprints202003.0396.v2
Subject: Engineering, Mechanical Engineering Keywords: production process design; design for manufacturability; fuzzy logic
Online: 27 March 2020 (13:01:50 CET)
The paper presents design methodology for the production process of a new product from the point of view of the assembly operations technology criterion (Design for Assembly - DFA) in the conditions of high-volume production. Mentioned are DFA methods and techniques used in the implementation of a new product. Author presents a new method to assess design for manufacturability based on fuzzy variables based on fuzzy variables. An example was given to illustrate the proposed course of action
COMMUNICATION | doi:10.20944/preprints202003.0408.v1
Subject: Engineering, Other Keywords: actuator; alternator; electrochemomechanical; inverter; more-than-Moore; oil-water interface; oscillator; pH; unconventional computing
Online: 27 March 2020 (11:34:27 CET)
In this article, we report the generation of alternating current by application of constant and ramping DC voltages across oil-water interfaces. The work reported here can be broadly divided into two parts depending on the shapes of oil-water interfaces i.e. flattened and curved. In the first part, an alternating current of ~100 nA (amplitude)was generated by applying a constant DC voltage of -3V& above across a free standing and flattened oil-water interface.In another part, an alternating current of ~150 nA (amplitude) was generated by applying a ramping up DC voltage starting from -5V to 5V, then again ramping back down to -5V for the free standing and curved interface. The suggested qualitative mechanism that engenders such a phenomenon includes the oil-water interface acting like a membrane. This membrane oscillates due to the electrophoretic movement of ions present in aqueous phase by application of a DC voltage across the interface.This electrophoretic movement of ions across oil-water interfaces causes the Faraday instabilities leading to oscillations of the said interface.This method could also be used to study the stress levels in the interfacial films between two immiscible liquids. It explores more-than-Moore’s paradigm by finding a substitute to a conventional alternator/inverter that generates alternating current upon applying DC voltage input. This work would be of substantial interest to researchers exploring alternatives to conventional AC generators that can be used in liquid environments and in the design of novel integrated circuits that could be used for unconventional computing applications.
Thu, 26 March 2020
ARTICLE | doi:10.20944/preprints202003.0397.v1
Subject: Engineering, Electrical & Electronic Engineering Keywords: New-CFAR; WS-CFAR; FPGA; Radar detection
Online: 26 March 2020 (15:38:32 CET)
In the radar system, detection represents a basic and important stage in the receiver side. The detection process is based on the thresholding criteria; two philosophies of this criteria, constant and adaptive threshold. The constant threshold is simple in design, but it has a mis-detection and does not control the false alarm rate. As for the adaptive threshold, it is powerful in target detection, and better control of the false alarm rate, where it is called Constant False Alarm Rate (CFAR). Lots of research in the CFAR design, but the gap in the previous works is that there is no CFAR algorithm can be working with all or most environmental fields and all or most target situations.In this paper, The CFAR, which can work with the most environment and most of the target situations, has been presented. The producing the design and implementation of the new practical CFAR processor is presented. Where, the new CFAR is a combination of the properties of three different CFAR algorithm (CA, OSGO, and OSSO), and from two different families; averaging and statistical. Where it has overperformed of it's is 97.25% for simulation and 96.25% for the implementable version for different target situations. The simulation analysis is made by using Matlab 2015, while the implementation is done by using Xilinx Spartan 700 3a.
ARTICLE | doi:10.20944/preprints202003.0396.v1
Subject: Engineering, Mechanical Engineering Keywords: production process design; design for manufacturability; fuzzy logic
Online: 26 March 2020 (15:26:42 CET)
The paper presents methodology for designing the production process of a new product from the point of view of the assembly operations technology criterion (Design for Assembly - DFA) in the conditions of high-volume production. Mentioned are DFA methods and techniques used in the implementation of a new product. Author presents a new method for assessing design for manufacturability based on fuzzy variables based on fuzzy variables. An example was given to illustrate the proposed course of action
Subject: Engineering, Electrical & Electronic Engineering Keywords: microwave photonic; signal channelization; integrated optical frequency comb
Online: 26 March 2020 (02:19:45 CET)
We report a broadband radio frequency (RF) channelizer with up to 92 channels using a coherent microcomb source. A soliton crystal microcomb, generated by a 49 GHz micro-ring resonator (MRR), is used as a multi-wavelength source. Due to its ultra-low comb spacing, up to 92 wavelengths are available in the C band, yielding a broad operation bandwidth. Another high-Q MRR is employed as a passive optical periodic filter to slice the RF spectrum with a high resolution of 121.4 MHz. We experimentally achieve an instantaneous RF operation bandwidth of 8.08 GHz and verify RF channelization up to 17.55 GHz via thermal tuning. Our approach is a significant step towards the monolithically integrated photonic RF receivers with reduced complexity, size, and unprecedented performance, which is important for wide RF applications ranging from broadband analog signal processing to digital-compatible signal detection.
ARTICLE | doi:10.20944/preprints202003.0379.v1
Subject: Engineering, Energy & Fuel Technology Keywords: vanadium redox flow battery; power density; limiting current; cell geometry; mass transfer; electrolyte mixing; static mixer; industrial design; multidisciplinary research; energy transitions
Online: 26 March 2020 (01:51:17 CET)
The world is moving to the next phase of the energy transition with high penetrations of renewable energy. Flexible and scalable redox flow battery (RFB) technology is expected to play an important role in ensuring electricity network security and reliability. Continuous performance improvements will further enhance their value by reducing parasitic losses and maximizing available energy conversion over broader operating conditions. Concentration overpotentials from poor internal reactant distribution at high and low states of charge (SOC) limit power densities and are thus an important area of investigation. However, efforts to address these coupled electrochemical phenomena can compromise mechanical performance. Modelling and simulation of cell design innovations have shown it is possible to reduce losses from pump energy while increasing the availability of active species where required. The combination of wedge-shaped cells with static mixers investigated in this paper can reduce pressure drop and improve energy efficiency. Toroidal vanadium redox flow battery (VRB/VRFB) designs incorporating this innovation are presented for further development to improve community engagement with the technology.
Tue, 24 March 2020
ARTICLE | doi:10.20944/preprints202003.0363.v1
Subject: Engineering, Civil Engineering Keywords: Artificial Neural Network; Schedule Performance Index (SPI); Cost Performance Index (CPI); To Complete Cost Performance Indicator (TCPI); Predicting; Models
Online: 24 March 2020 (14:49:20 CET)
The importance of this study may be defined by using the smart techniques to earned value indicators of residential buildings projects in Republic of Iraq, only one development intelligent forecasting model was presented to predict Schedule Performance Index (SPI), Cost Performance Index (CPI), and To Complete Cost Performance Indicator (TCPI) are defined as the dependent. The approach is principally influenced by the determining numerous factors which effect on the earned value management, that involves Iraqi historical data. In addition, six independent variables (F1: BAC, Budget at Completion., F2: AC, Actual Cost., F3, A%, Actual Percentage., F4: EV, Earned Value. F5: P%, Planning Percentage., and F6: PV, Planning Value) were arbitrarily designated and satisfactorily described for per construction project. It was found that ANN has the capability to envisage the dust storm with a great accuracy. The correlation coefficient (R) has been 90.00%, and typical accuracy percentage has been 89.00%.
ARTICLE | doi:10.20944/preprints202003.0355.v1
Subject: Engineering, Control & Systems Engineering Keywords: Thermo-Fluidic Process; Inkjet Printing; Feedback Control
Online: 24 March 2020 (08:30:10 CET)
This paper introduces a closed-loop control strategy for maintaining consistency of ink temperature in commercial Drop on Demand (DoD) inkjet printing. No additional sensors or additional actuators are installed in the printhead while achieving the consistency in ink temperature. To this end, this paper presents a novel in situ sensing-actuation policy at every individual ink-nozzle, where the jetting mechanism has three distinct roles. It is used for jetting liquid droplet onto the print media based on the print-job. It is used as a softsensor to estimate the real-time liquid temperature of the jetting nozzle. While not jetting liquid, it is used as a heating actuator to minimize the gradient of liquid temperature among jetting nozzles. The soft-sensing based in situ controller is implemented in an experimentally validated digital twin that models the thermo-fluidic processes of the printhead. The digital twin is scalable and flexible to incorporate an arbitrary number of inknozzles, making the control strategy applicable for future designs of the printhead.
Mon, 23 March 2020
ARTICLE | doi:10.20944/preprints202003.0334.v1
Subject: Engineering, Electrical & Electronic Engineering Keywords: industrial wireless sensor networks; IEEE~802.15.4g; smart utility networks; link reliability; adaptive techniques; modulation diversity
Online: 23 March 2020 (04:34:16 CET)
Adaptive mechanisms, such as channel hopping and packet replication, are used in low-power wireless networks to deal with the spatial and temporal variations in the link quality, and meet the reliability requirements of industrial applications (i.e., PDR>99%). However, the benefits of such mechanisms are limited and may have a large impact on end-to-end latency and energy consumption. Hence, in this paper we propose using adaptive modulation diversity, which allows to dynamically select different modulations, to improve link reliability. We present three adaptive modulation diversity selection strategies and validate them using the data derived from a real-world deployment using the IEEE 802.15.4g SUN modulations (i.e., SUN-FSK, SUN-OQPSK and SUN-ODFM) in an industrial environment. The results show that by using adaptive modulation diversity it is possible to improve link reliability regardless of node conditions.
ARTICLE | doi:10.20944/preprints202003.0330.v1
Subject: Engineering, Civil Engineering Keywords: Cross-Laminated Timber (CLT); laminated glass; hybrid facade element; thermal performance; energy efficiency; numerical modelling
Online: 23 March 2020 (03:41:03 CET)
Facade elements are known to represent a building component with multiple performance parameters to satisfy. Among others, “advanced facades” take advantage of hybrid solutions, like the assemblage of laminated materials. In addition to enhanced mechanical properties that are typical of optimally composed hybrid structural components, these systems are energy-efficient, durable, and offer lightening comfort and optimal thermal performance. This is the case of the structural solution developed in joint research efforts of the University of Zagreb and the University of Ljubljana, within the Croatian Science Foundation VETROLIGNUM project. The design concept involves the mechanical interaction of timber and glass load-bearing members, without sealing or bonded glass-to-timber surfaces. Laminated glass infilled timber frames are recognized as a new generation of structural members with relevant load-carrying capacity (and especially the enhancement of earthquake resistance of framed systems), but also energy-efficient and cost-effective solutions.
ARTICLE | doi:10.20944/preprints202003.0322.v1
Subject: Engineering, Industrial & Manufacturing Engineering Keywords: assembly systems; replenishment; stochastic lead times; holding cost; backlogging cost; purchase cost; optimization
Online: 23 March 2020 (01:05:03 CET)
Supplier selection/replacement strategies and optimized purchasing policies play a key role in efficient supply chain management in today’s dynamic market. Here we study supplier replacement in a one-level assembly system (OLAS) producing one type of finished product. To assemble the product, we need to provide multi-type components, but assembly will be interrupted if any single component is missing, and incoming units will get hoarded until the missing component arrives. The assembly process can be interrupted by various sources of uncertainty, including delays in component deliveries. There is consequently a non-negligible risk that the assembly process may get stopped any moment. This brings inventory-related costs, which should be minimized. Here we consider discrete lead-time distributions to mimic industry-world reality. We present a model that takes into account not only optimal assignment of component order release dates but also replacement of a critical supplier. For a given unit, we model several alternative suppliers with alternative pricing and lead-time uncertainties, and we evaluate the impact on the total assembly system. For a more general case where several suppliers may be replaced, we propose a genetic algorithm.
ARTICLE | doi:10.20944/preprints202003.0318.v1
Subject: Engineering, Civil Engineering Keywords: reuse; soil; X-ray techniques; binder; cement; durability; microstructure
Online: 23 March 2020 (00:23:23 CET)
Marine clay deposits are commonly found worldwide. Considering the cost of dumping and the related environmental concerns, an alternative solution involving the reuse of soils that have poor conditions is crucial. In this research, the authors examined the durability of marine deposited clays and compiled a corresponding database. The use of slag alone as a binder, at any percentage, increased the accumulated mass loss (ALM) up to 2%. However, the use of lime as the third binder seemed to accelerate the chemical reactions associated with the hydration of clay and cementitious material and to enhance the chemical stability, i.e., samples that included both lime and slag experienced the same ALM as samples treated with cement only. Scanning electron microscopy analysis confirmed the durability improvements of these clays. The proposed unconfined compressive strength and accumulated mass loss relationship yielded practical approximation for the fine- and coarse-grained soils blended with up to three binders until 60 days of curing.
Fri, 20 March 2020
ARTICLE | doi:10.20944/preprints202003.0317.v1
Subject: Engineering, Mechanical Engineering Keywords: Plasma keyhole arc welding; X-ray observation; Heat transportation; Eddy; Convective pattern
Online: 20 March 2020 (13:03:13 CET)
This investigation aims to discuss the formation process of eddies and the heat transportation in plasma keyhole arc welding. In order to clarify this issue, the measurement of the convection inside the weld pool, the convection on the weld pool surface, also the temperature distribution on the weld pool surface were carried out. The results showed that two eddies were found in the weld pool, which is controlled mainly through the shear force by the plasma flow acting on the weld pool surface. The magnitude, extent and direction of the shear force are thought to be determined primarily by the variation of keyhole profile. The relative shape and strength of each eddy is largely changed depending on the change of the keyhole profile when nozzle diameter changed. These relative strengths of each eddy are considered to decisively govern the heat transport in the weld pool coinciding with the direction of eddies. A larger eddy near the lower part of the keyhole inside the weld pool was found out in the case of 1.6 mm, meanwhile a upward larger eddy was found out near the upper part of the keyhole inside the weld pool in the case of 2.4 mm.
ARTICLE | doi:10.20944/preprints202003.0305.v1
Subject: Engineering, Mechanical Engineering Keywords: refractories; mortarless masonry; mechanical homogenization; thermomechanical modeling; steel ladle
Online: 20 March 2020 (04:56:11 CET)
Mortarless refractory masonry structures are widely used in the steel industry for the linings of many high-temperature industrial applications including steel ladle. The design and the optimization of these components require accurate numerical models that consider the presence of joints as well as joints closure and opening due to cyclic heating and cooling. The present work reports on the formulation, numerical implementation, validation, and application of homogenized numerical models for simulation of refractory masonry structures with dry joints. The validated constitutive model has been used to simulate a steel ladle and to analyze its transient thermomechanical behavior during a typical thermal cycle of steel ladle. 3D solution domain, enhanced thermal and mechanical boundary conditions have been used. Parametric studies to investigate the impact of joints thickness on the thermomechanical response of the ladle have been carried out. The results clearly demonstrate that the thermomechanical behavior of mortarless masonry is orthotropic nonlinear due to gradual closure and reopening of joints with the increase and decrease of temperature. Also, resulting thermal stresses increase with the increase of temperature and decrease with the increase of joints thickness.
Thu, 19 March 2020
ARTICLE | doi:10.20944/preprints202003.0300.v1
Subject: Engineering, Electrical & Electronic Engineering Keywords: coronavirus; COVID-19; diagnosis; deep features; SVM
Online: 19 March 2020 (13:49:49 CET)
The detection of coronavirus (COVID-19) is now a critical task for the medical practitioner. The coronavirus spread so quickly between people and approaches 100,000 people worldwide. In this consequence, it is very much essential to identify the infected people so that prevention of spread can be taken. In this paper, the deep learning based methodology is suggested for detection of coronavirus infected patient using X-ray images. The support vector machine classifies the corona affected X-ray images from others using the deep feature. The methodology is beneficial for the medical practitioner for diagnosis of coronavirus infected patient. The suggested classification model, i.e. resnet50 plus SVM achieved accuracy, FPR, F1 score, MCC and Kappa are 95.38%,95.52%, 91.41% and 90.76% respectively for detecting COVID-19 (ignoring SARS, MERS and ARDS). The classification model ResNet50 plus SVM is superior compared to other classification models. The result is based on the data available in the repository of GitHub, Kaggle and Open-i as per their validated X-ray images.
Wed, 18 March 2020
ARTICLE | doi:10.20944/preprints202003.0283.v1
Subject: Engineering, Mechanical Engineering Keywords: piezoelectric ceramic; piezo-composite actuator; unimorph; piezoelectric single crystal; LIPCA
Online: 18 March 2020 (02:58:14 CET)
Research on piezo-composite actuators has been actively conducted over the past two decades as a response to strong demand for light, compact actuators to replace electro-magnetic motor actuators in micro robots, small flying drones, and compact missile systems. Layered piezo-composite unimorph actuators have been studied to provide active vibration control of thin-walled aerospace structures, control the shapes of aircraft wing airfoils, and control the fins of small missiles, because they require less space and provide better frequency responses than conventional electro-magnetic motor actuator systems. However, based on the limited actuation strains of conventional piezo-composite unimorph actuators with poly-crystalline piezoelectric ceramic layers, they have not been implemented effectively as actuators for small aerospace vehicles. In this study, a lightweight piezo-composite unimorph actuator (LIPCA-S2) was manufactured and analyzed to predict its flexural actuation displacement. It was found that the actuated tip displacement of a piezo-composite cantilever could be predicted accurately using the proposed prediction model based on the nonlinear properties of the piezoelectric strain coefficient and elastic modulus of a piezoelectric single crystal.
Sun, 15 March 2020
ARTICLE | doi:10.20944/preprints202003.0250.v1
Subject: Engineering, Civil Engineering Keywords: carbon fiber; cement; sustainability; marble powder; bottom ash; paste
Online: 15 March 2020 (15:56:26 CET)
The damage caused by global warming is rapidly increasing, and its adverse effects become more evident with each passing day. Although it is known that the use of alternative binder materials in concrete would decrease this negative effect, reluctance to new composites continues. Waste use plays a vital role in sustainability studies. In this study, pure cement paste was prepared and enriched with carbon fiber. This study investigated the wide range of volume fraction of carbon fiber in cement-based composites. Two different industrial wastes, marble dust, and bottom ash were chosen and mixed with cement and four different (0.3%, 0.75%, 1.5%, and 2.5%) carbon fiber volume fractions. Based on physical, mechanical, and durability tests at 7, 28, and 56-days of curing, the composites were resistant to sulfate and seawater attack. The 0.75% carbon fiber addition seems to be an optimum volume percentage beyond which both physical and mechanical properties were adversely affected. The composites with 0.75% carbon fiber have reached 48.4 MPa and 47.2 MPa at 56-days of curing for marble dust and bottom ash mixture groups, respectively.
Subject: Engineering, Electrical & Electronic Engineering Keywords: optical fibre data; transmission; microcomb
Online: 15 March 2020 (15:20:23 CET)
Micro-combs [1-4] - optical frequency combs generated by integrated micro-cavity resonators – offer the full potential of their bulk counterparts [5,6], but in an integrated footprint. The discovery of temporal soliton states (DKS – dissipative Kerr solitons) [4,7-11] as a means of mode-locking micro-combs has enabled breakthroughs in many fields including spectroscopy [12,13], microwave photonics , frequency synthesis , optical ranging [16,17], quantum sources [18,19], metrology [20,21] and more. One of their most promising applications has been optical fibre communications where they have enabled massively parallel ultrahigh capacity multiplexed data transmission [22,23]. Here, by using a new and powerful class of micro-comb called “soliton crystals” , we achieve unprecedented data transmission over standard optical fibre using a single integrated chip source. We demonstrate a line rate of 44.2 Terabits per second (Tb/s) using the telecommunications C-band at 1550nm with a spectral efficiency – a critically important performance metric - of 10.4 bits/s/Hz. Soliton crystals exhibit robust and stable generation and operation as well as a high intrinsic efficiency that, together with a low soliton micro-comb spacing of 48.9 GHz enable the use of a very high coherent data modulation format of 64 QAM (quadrature amplitude modulated). We demonstrate error free transmission over 75 km of standard optical fibre in the laboratory as well as in a field trial over an installed metropolitan optical fibre network. These experiments were greatly aided by the ability of the soliton crystals to operate without stabilization or feedback control. This work demonstrates the capability of optical soliton crystal micro-combs to perform in demanding and practical optical communications networks.
ARTICLE | doi:10.20944/preprints202003.0245.v1
Subject: Engineering, Civil Engineering Keywords: bottom ash; basalt fiber; paste; strength; durability; sustainability
Online: 15 March 2020 (14:15:01 CET)
Extinction of natural resources builds up pressure on governments to invest in research to find more sustainable resources for construction sector. Earlier studies on mortar and concrete show that bottom ash and basalt fiber are independently alternative binder in the concrete sector. This study aims to use bottom ash and basalt fiber blends as alternative novel-based composites in pure cement paste. Strength and durability properties of two different percentages of bottom ash (40% and 50%) and three volume fractions of basalt fiber (0.3%, 0.75%, and 1.5%) were used at three curing periods (7, 28, and 56 days). In order to measure physical properties of the basalt-reinforced bottom ash cement paste composites flowability, dry unit weight, porosity and water absorption measurements at 7, 28, and 56 days of curing were performed. Furthermore, mechanical properties of composites determined by unconfined compressive strength and flexural strength tests. Finally, to assess the durability sulfate-resistance and seawater-resistance tests have been performed on composites at 28 and 56 days of curing. Results showed that addition of basalt fiber improves physical, mechanical and chemical stability properties of paste up to a limiting basalt fiber addition (0.3% volume fraction) where above an adverse effect have been monitored. It is clear that observed results can lead to development of sustainability strategies in the concrete industry by utilizing bottom ash and basalt fiber as an alternative binder.
ARTICLE | doi:10.20944/preprints202003.0240.v1
Subject: Engineering, Civil Engineering Keywords: SPH; DNS; dilute suspensions; non-colloidal; contact models; repulsive force
Online: 15 March 2020 (03:15:19 CET)
Suspensions and their applications can be found in many engineering, environmental or medical fields. Considering the special field of dilute suspensions, possible applications are cement paste or procedural processes in the production of medication or food. While the homogenized behavior of these applications is well understood, contributions in the field of pore-scale fully resolved numerical simulations with non-spherical particles are rare. Using Smoothed Particle Hydrodynamics as a simulation framework we therefore present a model for Direct Numerical Simulations of single-phase fluid containing non-spherically formed solid aggregates. Notable and discussed model specifications are the surface-coupled fluid-solid interaction forces as well as the contact forces between solid aggregates. Moreover we simulate and analyze the behavior of dilute non-colloidal suspensions of non-spherical solid particles in Newtonian fluids. The focus of this contribution is the numerical model for suspensions and its implementation in SPH. Therefore shown numerical examples present application examples for a first numerical analysis of influence factors in suspension flow. Results show that direct numerical simulations reproduce known phenomena like shear induced migration very well. Moreover the present investigation exemplifies the influence of concentration and form of particles on the flow processes in greater detail.
ARTICLE | doi:10.20944/preprints202003.0236.v1
Subject: Engineering, Civil Engineering Keywords: seismic vulnerability; fuzzy logic system; Interval Type-2 Fuzzy logic; retrofit prioritization; damage category classification
Online: 15 March 2020 (01:54:35 CET)
Rapid Visual Screening (RVS) is a procedure that estimates structural scores for buildings and prioritize their retrofit and upgrade requirements. Despite the speed and simplicity of RVS, many of the collected parameters are non-commensurable and include subjectivity due to visual observations. It might cause uncertainties in the evaluation, which emphasizes the use of a fuzzy-based method. This study aims to propose a novel RVS methodology based on the interval type-2 fuzzy logic system (IT2FLS) to set the priority of vulnerable building to undergo detailed assessment while covering uncertainties and minimizing their effects during evaluation. The proposed method estimates the vulnerability of a building, in terms of Visual Damage Index, considering the number of stories, age of building, plan irregularity, vertical irregularity, building quality, and peak ground velocity, as inputs with a single output variable. Applicability of the proposed method has been investigated using a post-earthquake damage database of 28 reinforced concrete buildings from the Bingöl earthquake in Turkey.
ARTICLE | doi:10.20944/preprints202003.0233.v1
Subject: Engineering, Civil Engineering Keywords: roller compacted concrete pavement; classification-regression models; feature selection; mechanical properties; Monte-Carlo uncertainty
Online: 15 March 2020 (01:32:44 CET)
In the field of pavement engineering, the determination of the mechanical characteristics is one of the essential process for reliable material design and highway sustainability. Early determination of mechanical characteristics of pavement is highly essential for road and highway construction and maintenance. Tensile strength (TS), compressive strength (CS) and flexural strength (FS) of roller compacted concrete pavement (RCCP) are very crucial characteristics as they are necessitated for many data from mixture proportions as input variables. In this research, the classification-based regression models named Random Forest (RF), M5rule model tree (M5rule), M5prime model tree (M5p) and Chi-square Automatic Interaction Detection (CHAID) are developed for simulation of the mechanical characteristics of RCCP. A comprehensive and reliable dataset comprising 621, 326 and 290 data records for CS, TS and FS experimental cases extracted from several open sources over the literature. The mechanical properties are developed based on influential inputs combination that processed using Principle Component Analysis (PCA). The applied PCA method as feature selection is specified that volumetric/weighted content forms of experimental variables (e.g., coarse aggregate, fine aggregate, supplementary cementitious materials, water and binder) and specimens’ age are the most effective inputs to generate the better performances. Several statistical metrics are measured to evaluate proposed classification-based regression models. RF model revealed an optimistic classification capacity of the CS, TS and FS prediction of the RCCP in comparison with the CHAID, M5rule, and M5p models. The research is extended for the results verification using Monte-carlo model for the uncertainty and sensitivity of variables importance analysis. Overall, the proposed methodology indicated a reliable soft computing model that can be implemented for the material engineering construction and design.
Thu, 12 March 2020
ARTICLE | doi:10.20944/preprints202003.0219.v1
Online: 12 March 2020 (14:30:23 CET)
The paper investigates the performance of a full analog self-jammer canceller able to operate in UHF RFID devices. The scheme has been realized using only SMT devices avoiding custom designed components. The paper analyzes the theoretical performance and experimental validation using a modular microwave technology approach.
Subject: Engineering, Electrical & Electronic Engineering Keywords: integrator; Kerr micro-comb; RF signal processing
Online: 12 March 2020 (04:05:22 CET)
We demonstrate a photonic RF integrator based on an integrated soliton crystal micro-comb source. By multicasting and progressively delaying the input RF signal using a transversal structure, the input RF signal is integrated discretely. Up to 81 wavelengths are provided by the microcomb source, which enable a large integration time window of ~6.8 ns, together with a time resolution as fast as ~84 ps. We perform signal integration of a diverse range of input RF signals including Gaussian pulses with varying time widths, dual pulses with varying time intervals and a square waveform. The experimental results show good agreement with theory. These results verify our microcomb-based integrator as a competitive approach for RF signal integration with high performance and potentially lower cost and footprint.
Subject: Engineering, Electrical & Electronic Engineering Keywords: optical neural network; microcomb
Online: 12 March 2020 (03:41:39 CET)
Optical artificial neural networks (ONNs) — analog computing hardware tailored for machine learning [1,2] — have significant potential for ultra-high computing speed and energy efficiency . We propose a new approach to architectures for ONNs based on integrated Kerr micro-comb sources  that is programmable, highly scalable and capable of reaching ultra-high speeds. We experimentally demonstrate the building block of the ONN — a single neuron perceptron — by mapping synapses onto 49 wavelengths of a micro-comb to achieve a high single-unit throughput of 11.9 Giga-FLOPS at 8 bits per FLOP, corresponding to 95.2 Gbps. We test the perceptron on simple standard benchmark datasets — handwritten-digit recognition and cancer-cell detection — achieving over 90% and 85% accuracy, respectively. This performance is a direct result of the record small wavelength spacing (49GHz) for a coherent integrated microcomb source, which results in an unprecedented number of wavelengths for neuromorphic optics. Finally, we propose an approach to scaling the perceptron to a deep learning network using the same single micro-comb device and standard off-the-shelf telecommunications technology, for high-throughput operation involving full matrix multiplication for applications such as real-time massive data processing for unmanned vehicle and aircraft tracking.
Wed, 11 March 2020
ARTICLE | doi:10.20944/preprints202003.0179.v1
Subject: Engineering, Mechanical Engineering Keywords: fast tool servo; voice coil motor; flexure mechanism; resonant controller
Online: 11 March 2020 (04:04:49 CET)
In this paper, a voice coil motor (VCM) actuated fast tool servo (FTS) system is developed for diamond turning. To guide motions of the VCM actuator, a crossed double parallelogram flexure mechanism is selected featuring totally symmetric structure with high lateral stiffness. To facilitate the determination of the multi-physical parameters, analytical models of both electromagnetic and mechanical systems are developed. The designed FTS with balanced stroke and natural frequency is then verified through the finite element analysis. Finally, the prototype of the VCM actuated FTS is fabricated and experimentally demonstrated to have a stroke of ±59.02 μm and a first natural frequency of 253 Hz. By constructing a closed-loop control using PID controller with the internal-model based resonant controller, the error for tracking a harmonic trajectory with ±10 μm amplitude and 120 Hz frequency is obtained to be ±0.2 μm, demonstrating the capability of the FTS for high accuracy trajectory tracking.
Tue, 10 March 2020
REVIEW | doi:10.20944/preprints202003.0165.v1
Subject: Engineering, Electrical & Electronic Engineering Keywords: Underwater Wireless Sensor Network (UWSN); Routing Protocols; Acoustic Communication; Multi-hop communication; Energy-Efficient; Reliable
Online: 10 March 2020 (10:44:22 CET)
Water covers a greater part of the earth's surface. Even though we know very little about the underwater world as most parts of it remain unexplored. Oceans including other water bodies hold huge natural resources and also the aquatic lives. These are mostly unexplored and very few of those are known due to unsuited and hazardous environments for the human to explore. This vast underwater world can be monitored remotely from a distant location with much ease and less risk. To monitor water-bodies remotely in real-time, sensor networking has been playing a great role. It is needed to deploy a wireless sensor network over the volume which we want to surveil. For vast water bodies like oceans, rivers and large lakes, data is collected from the different heights of the water level which is sent to the surface sink. Unlike terrestrial communication, radio waves and other conventional mediums can't serve the purpose of underwater communication as they pose high attenuation and very reduced transmission range. Rather an acoustic medium can transmit data more efficiently and reliably in comparison to other mediums. To transmit data reliably from the bottom of the sea to the sinks at the surface, multi-hop communication is needed which must involve a certain scheme. For seabed to surface sink communication, leading researchers have proposed different routing protocols. The goal of these routing protocols is to make underwater communication more reliable, energy-efficient and delay efficient thus to improve the performance of the overall communication. This paper surveys the advancement and applications of the routing protocols which eventually helps in finding the most efficient routing protocol for the Underwater Wireless Sensor Network (UWSN).
ARTICLE | doi:10.20944/preprints202003.0162.v1
Online: 10 March 2020 (10:26:12 CET)
This publicly available simulation analysis compares baseline construction options versus sustainable options and evaluates both break-even costs as well as environmental effects. The simulation (https://rminator.shinyapps.io/sustain4/) provides users with comparative estimates based upon existing research on costs. This is the first simulation of its type that quantifies multiple sustainable construction options, associated break-even points, and environmental considerations for public use. Results estimate that a 100% solar solution for the baseline 3,000 square foot / 279 square meter house with 2 occupants results in a break-even of 9 years. The simulation includes options for rainwater harvesting or wells, Icynene foam, engineered lumber, Energy Star windows and doors, low flow water fixtures, aerobic / non-aerobic waste treatment or municipal services, and many other options. This is the first simulation of its type to provide publicly available sustainable construction analysis based on research, and it illustrates that sustainable construction might be both green for the environment and green for the pocketbook.
ARTICLE | doi:10.20944/preprints202003.0158.v1
Subject: Engineering, Energy & Fuel Technology Keywords: energy; demand; forecasting; deep; learning; machine; convolutional; artificial; neural; networks
Online: 10 March 2020 (03:40:31 CET)
This paper investigates the use of deep learning techniques to perform energy demand forecasting. Specifically, the authors have adapted a deep neural network originally thought for image classification and composed of a convolutional neural network (CNN) followed by a multilayered fully connected artificial neural network (ANN). The convolutional part of the network was fed with a grid of temperature forecasting data distributed in the area of interest in order to extract a featured temperature. The subsequent ANN is then fed with this calculated temperature along with other data related to the timing of the forecast. The proposed structure was first trained and then used in a real setting aimed to provide the French energy demand forecast using ARPEGE forecasting weather data. The results show that the performance of this approach is in the line of the performance provided by the reference RTE subscription-based service, which opens the possibility to obtain high accuracy forecasting using widely accessible deep learning techniques through open-source machine learning platforms.
ARTICLE | doi:10.20944/preprints202003.0157.v1
Subject: Engineering, Mechanical Engineering Keywords: stress state; pressure gradient; normal contact; tangential contact; friction; axial symmetry; method of dimensionality reduction
Online: 10 March 2020 (03:22:49 CET)
The Hertzian contact theory, as well as most of the other classical theories of normal and tangential contact, provides displacements and the distribution of normal and tangential stress components directly in the contact surface. However, other components of the full stress tensor in the material may essentially influence the material behaviour in contact. Of particular interest are principal stresses and the equivalent von Mises stress, as well as the gradient of the hydrostatic pressure. For many engineering and biomechanical problems, it would be important to find these stress characteristics at least in the contact plane. In the present paper, we show that the complete stress state in the contact plane can be easily found for axially symmetric contacts under very general assumptions. We provide simple explicit equations for all stress components and the normal component of the gradient of hydrostatic pressure in the form of one-dimensional integrals.
Mon, 9 March 2020
ARTICLE | doi:10.20944/preprints202003.0150.v1
Subject: Engineering, General Engineering Keywords: CFD; numerical optimization; CAD parametrization; cloud-based; design space exploration; SSIM
Online: 9 March 2020 (09:50:23 CET)
In this manuscript, an automated framework dedicated to design space exploration and design optimization studies is presented. The framework integrates a set of numerical simulation, computer-aided design, numerical optimization, and data analytics tools using scripting capabilities. The tools used are open-source and freeware, and can be deployed on any platform. The main feature of the proposed methodology is the use of a cloud-based parametrical computer-aided design application, which allows the user to change any parametric variable defined in the solid model. We demonstrate the capabilities and flexibility of the framework using computational fluid dynamics applications; however, the same workflow can be used with any numerical simulation tool (e.g., a structural solver or a spread-sheet) that is able to interact via a command line interface or using scripting languages. We conduct design space exploration and design optimization studies using quantitative and qualitative metrics, and to reduce the high computing times and computational resources intrinsic to these kinds of studies, concurrent simulations and surrogate-based optimization are used.
Sun, 8 March 2020
ARTICLE | doi:10.20944/preprints202003.0140.v1
Subject: Engineering, Biomedical & Chemical Engineering Keywords: Monte Carlo simulation; propagation; wavelength; low-level laser therapy LLLT
Online: 8 March 2020 (16:41:17 CET)
Nowadays, the uses of laser and optics in the medical areas are extremely vivid, especially low-level laser therapy. The light with the wavelength of 633 nm to 1200 nm could penetrate and propagate deep in biological tissue. To develop the low-level laser therapy device, optimizing light delivery is critical to accurately stimulate the biological effects inside the biological tissue. Nevertheless, each form of the tissues at each zone on the body had various refractive optic, absorption, scattering, and anisotropy coefficients. This paper describes the simulation results of low-level laser propagation from skin surface at the lower spine, the knee, the femur and the prostate gland with four wavelengths (633 nm, 780 nm, 850 nm, and 940 nm) by the Monte Carlo method. These simulation results are the base for developing the low-level laser therapy device, that could be used in clinical for treating the fracture, knee osteoarthritis, spinal degeneration, and benign prostatic hypertrophy.
ARTICLE | doi:10.20944/preprints202003.0131.v1
Subject: Engineering, Mechanical Engineering Keywords: adhesion; hysteresis; energy dissipation; JKR theory; MDR; specific surface energy; hetero-geneity
Online: 8 March 2020 (04:31:20 CET)
According the JKR theory of adhesive contact, changes of the contact configuration after formation of the adhesive neck and before detaching are completely reversible. This means, that after formation of the initial contact, the force-distance dependencies should coincide, independently on the direction of the process (indentation or pull-off). In the majority of real systems, this invariance is not observed. The reasons for this may be either plastic deformation in the contacting bodies or surface roughness. One further mechanism of irreversibility (and corresponding energy dissipation) may be chemical heterogeneity of the contact interface leading to the spatial dependence of the specific work of adhesion. In the present paper, this "chemical" mechanism is analyzed on a simple example of an axisymmetric contact (with axisymmetric heterogeneity). It is shown that in the asymptotic case of a "microscopic heterogeneity", the system follows, during both indentation and pull-off, JKR curves, however, corresponding to different specific surface energies. After the turning point of the movement, the contact area first does not change and the transition from one JKR curve to the other occurs via a linear dependency of the force on indentation depth. The macroscopic behavior is not sensitive to the absolute and relative widths of the regions with different surface energy but depends mainly on the values of the specific surface energy.
ARTICLE | doi:10.20944/preprints202003.0126.v1
Subject: Engineering, Construction Keywords: change order; pricing; game theory; evolutionary stable strategy (ESS); system dynamics
Online: 8 March 2020 (01:19:49 CET)
Change orders have received considerable attention from researchers thus far, but none have considered pricing strategies of change orders through the interaction between general contractors and subcontractors. Previous studies found that contractors’ opportunistic bidding considering beyond-contractual reward (BCR) in the execution stage can be reduced by improving the construction management system and strengthening the supervision of contractors’ performance. However, the BCR remains in ecology of construction engineering. This study proposes an integrated evolutionary game theory-system dynamics model (ET-SD model) and simulates the pricing strategy of change orders between general contractors and subcontractors to explore the root cause of BCR phenomenon. Sensitivity analysis on the evolutionary dynamics of payoff is explored. Results reveal that change orders with BCR maintain Nash equilibrium and evolutionary stable strategy (ESS) unless changing the payoff structure between general and subcontractors’ pricing strategies. This study presents important managerial insights from the evolutionary game perspectives, nature of change orders, and payoff of the alternative.
Sat, 7 March 2020
ARTICLE | doi:10.20944/preprints202003.0122.v1
Subject: Engineering, Mechanical Engineering Keywords: unconfined blast; confined blast; digital image correlation; dynamic response; blast loading
Online: 7 March 2020 (15:40:40 CET)
Defensive structure is important in transportation field for kinds of intentional or unintentional explosion. Structures subjected to unconfined and confined explosion will bear different blast loads and their dynamic responses are different. The present work focus on the dynamic response mechanism of steel plate under unconfined and confined blast loads through both numerical and experimental studies. In the experiment, Digital Image Correlation (DIC) technique was applied to record and analyze the dynamic response process of large-scale field blast test. The DIC measured curve and the numerical calculated curves agrees well in both the trends and the peak values. Then, the dynamic response mechanism of steel plate under unconfined blast (UB) load and confined blast (CB) load were compared and discussed. Results show that the dynamic response of plate can be divided into three phases under both UB and CB loads, while with different mechanism. In phase I, plastic hinge starts from the center and moves to the boundary in UB condition, while in case of CB, plastic hinge occurs close to the boundary and moves in the opposite direction. In phase II, two plastic hinge lines propagates towards each other, and a platform exists between the boundary and the central area remains undeformed in UB condition, while in CB condition, larger deformation in peripheral region rather than central area produces.
Subject: Engineering, Electrical & Electronic Engineering Keywords: CNFETs; Approximate Computing; Multiple-Valued Logic
Online: 7 March 2020 (02:53:54 CET)
In recent decades, power consumption has become an essential factor in attracting the attention of integrated circuit (IC) designers. Multiple-valued logic (MVL) and approximate computing are some techniques that could be applied to integrated circuits to make power-efficient systems. By utilizing MVL-based circuits instead of binary logic, the information conveyed by digital signals increases, and this reduces the required interconnections and power consumption. On the other hand, approximate computing is a class of arithmetic computing used in systems where the accuracy of the computation can be traded-off for lower energy consumption. In this paper, we propose novel designs for exact and inexact ternary multipliers based on carbon-nanotube field-effect transistors (CNFETs). The unique characteristics of CNFETs make them a desirable alternative to MOSFETs. The simulations are conducted using Synopsys HSPICE. The proposed design is compared against existing ternary multipliers. The results show that the proposed exact multiplier reduces energy consumption by up to 6X. At the same time, the best inexact design improves energy efficiency by up to 35X compared to the latest state-of-the-art methods. Using the imprecise multipliers for image processing provides evidence that these proposed designs are a low-power system with an acceptable error.
CONCEPT PAPER | doi:10.20944/preprints202003.0112.v1
Subject: Engineering, Civil Engineering Keywords: drain water treatment; Belbeis drain; compact units; reuse; sand filter; packing material
Online: 7 March 2020 (02:50:05 CET)
In an attempt to improve the quality of the agricultural drain in Egypt for its reuse again in the irrigation, low cost solution such as sand filter along with/ without other filtration media have been used in this research, As a result of that, pilot plant of sand filter mixed with other filtration media was tested for its ability to improve the sand performance in removing the suspended solids and organic matters from agricultural drain water of the Belbeis drain (in Sharkia governorate in Egypt). Only sand compared with sand with sponge and sand with Liyan Nanfang activated carbon (L.N.A.C) have been tested to find the optimum mixing sand/ medium ratio &optimum infiltration rate. The work has been done on four runs. It was found that sand mixed with sponge gave the best removal efficiency compared to that of the sand only and the sand mixed with L.N.A.C. The results presented that the concentration of CODt, CODsol and TSS was reduced from 125, 47 and 162 mg/l to 44, 34 and 28 mg/l respectively at optimum infiltration rate of 2 m3/m2/d for sand mixed with sponge.
Fri, 6 March 2020
Subject: Engineering, Energy & Fuel Technology Keywords: photovoltaics; solar energy; Father Verspieren; solar energy in Africa; solar economy; solar pump
Online: 6 March 2020 (04:12:12 CET)
Almost fifty years after the first installations, I identify the main lessons learned from fighting drought and poverty in Africa with direct solar-powered pumps thanks to Father Bernard Verspieren and Mali Aqua Viva. Six main findings and three main recommendations emerge from the present analysis which are of direct relevance to all Africa’s countries whose population has gone from 438 million in 1977 to 1308 million in 2019, with about 600 million still having no access to electricity. In place of “awareness campaigns”, I recommend to organize practice-oriented workshops on solar-powered irrigation and rainwater harvesting held by professional educators of newly established solar energy national institutes. In agreement with today’s expanded approach to education in solar energy, and with the key adult learning principle of motivation to learn, said education will include the economic and social aspects of distributed “generation” of energy and water from sunlight and rainfall.
Thu, 5 March 2020
ARTICLE | doi:10.20944/preprints201911.0046.v2
Subject: Engineering, Civil Engineering Keywords: Rayleigh backscatter; distributed optical strain measurement; fiber optic; concrete; shrinkage; coating
Online: 5 March 2020 (15:24:39 CET)
The distributed fiber optic strain measurement based on Rayleigh scattering has recently become increasingly popular in automotive or mechanical engineering for strain monitoring and in the construction industry, especially structural health monitoring. This technology enables the monitoring of strain along the entire fiber length. This article addresses integrating optical fibers of different coatings into the concrete matrix to measure the shrinkage deformations. However, previous studies do not give a clear statement about the strain transfer losses of fiber optic sensors in this application. In this context, three different coating types were investigated regarding their strain transfer. The fibers were integrated into fine-grained concrete prisms, and the shrinkage strain was compared with a precise dial gauge. The analysis shows a high correlation between the reference method and the fiber measurement, especially with the Ormocer coating. The used acrylate coating is also consistent in the middle area of the specimen but requires a certain strain introduction length to indicate the actual strain. The main result of this study is a recommendation for fiber coatings for shrinkage measurement in fine-grain concretes using the distributed fiber optic strain measurement. In addition, the advantages and disadvantages of the measurement method are presented.
ARTICLE | doi:10.20944/preprints202003.0088.v1
Subject: Engineering, Civil Engineering Keywords: Major ions; Physicochemical parameters; Pearson’s correlation matrix; Regression; Water Quality Index (WQI)
Online: 5 March 2020 (12:02:36 CET)
This work evaluates the surface water quality in terms of physico-chemical parameters of the Brahmani River, Odisha using statistical analysis involving the calculation of correlation coefficient and regression equation. Besides this, the work also highlights and draws attention towards the “Water Quality Index” in a simplified format which may be used at large and could represent the reliable picture of water quality. Surface water quality data is taken from OSPCB of various location i.e. Panposh D/S, Rourkela D/S, Rengali, Talcher U/S, Kamalanga D/S, Bhuban, Pattamundai and was assessed for summer, monsoon, winter for the years 2011, 2012, 2013, 2014 and 2015. Average of values, minimum of values and maximum of values of water quality parameters were obtained seasonally over the above mentioned years. Besides this, the standard deviation for the water quality parameters was also obtained for water quality parameters namely pH, Temperature, DO, TDS, Alkalinity, EC, Na+, Ca2+, Mg2+, K+, F-, Cl-, NO3-, SO42- and PO42-. Seasonal changes in various physical and chemical parameters were analysed.The values obtained were compared with the guideline values for drinking water by Bureau of Indian Standard (BIS). A systematic correlation and regression study is carried out for three seasons, showed linear relationship among different water quality parameters. This provides an easy and rapid method of monitoring water quality. Highly significant (0.8< r <1.0), moderately significant (0.6< r <0.8) and significant (0.5< r <0.6) correlations between the parameters have been worked out. High correlation coefficient has been observed between TDS,EC-Na+, Ca2+, Cl-, SO42- ; Na+- Cl-. From the collected quantities, certain parameters were selected to derive WQI for the variations in water quality of each designated sampling site. WQI of Brahmani River ranged from 36.7 to 44.1 which falls in the range of good quality of water.Panposh D/S and Rourkela D/S showed poor water quality in summer and winter season. It is shown that WQI may be a useful tool for assessing water quality and predicting trend of variation in water quality at differentlocations in the Brahmani River.
REVIEW | doi:10.20944/preprints202003.0084.v1
Subject: Engineering, Electrical & Electronic Engineering Keywords: Single-diode model; Five-parameter model; Photovoltaic panels; Analytics method
Online: 5 March 2020 (11:41:58 CET)
In this paper, the seven traditional models of PV modules are reviewed comprehensively to find out the appropriate model to be reliable. All the models are validated using the Matlab code and make a graphical comparison. The accuracy and convergence of each model are evaluated using data of manufactured PV panels. Then, a novel model is proposed showing its consistent performance. The most three key parameters of single-diode model are self revised to adapt to various type of PV modules. This new method is verified in three types of PV panels' data measured by National Renewable Energy Laboratory (NREL), US. The validated data show promising results when the error RMSEs' range of the proposed model is under 0.36.
ARTICLE | doi:10.20944/preprints202003.0079.v1
Subject: Engineering, Control & Systems Engineering Keywords: micro segmented genetic algorithm; multicore embedded system; parallel processing
Online: 5 March 2020 (03:23:59 CET)
This paper presents a novel micro-segmented genetic algorithm (μsGA) to identify the best solution for the locomotion of a quadruped robot designed on a rectangular ABS plastic platform. We compare our algorithm with three similar algorithms found in the specialized literature: a standard genetic algorithm (GA), a micro-genetic algorithm (μGA), and a micro artificial immune system (μAIS). The quadruped robot prototype guarantees the same conditions for each test. The platform was developed using 3D printing for the structure and can accommodate the mechanisms, sensors, servomechanisms as actuators. It also has an internal battery and a multicore embedded system (mES) to process and control the robot locomotion. This research proposes a μsGA that segments the individual into specific bytes. μGA techniques are applied to each segment to reduce the processing time; the same benefits as the GA are obtained, while the use of a computer and the high computational resources characteristic of the GA are avoided. This is the reason why some research in robot locomotion is limited to simulation. The results show that the performance of μsGA is better than the three other algorithms (GA, μGA and AIS). The processing time was reduced using a mES architecture that enables parallel processing, meaning that the requirements for resources and memory were reduced. This research solves the problem of continuous locomotion of a quadruped robot, and gives a feasible solution with real performance parameters using a μsGA bio-micro algorithm and a mES architecture.
Wed, 4 March 2020
Subject: Engineering, Energy & Fuel Technology Keywords: Fuel Cell; Electrolysis; Hydrogen; Operando measurement; Degradation
Online: 4 March 2020 (15:00:01 CET)
Durability and performance of electrochemical energy converters such as fuel cells and electrolysers are not only dependent on the properties and the quality of the used materials. They strongly depend on operation conditions. Variations in external parameters, such as flow, pressure, temperature and, obviously, load can lead to significant local changes of current density, even local transients. The segmented cell technology was developed with the purpose to gain insight into local operation conditions in electrochemical cells, during operation. The operando measurement of the local current density and temperature distribution allows effective improvement of operation conditions, mitigation of potentially critical events and assessment of the performance of new materials. The segmented cell, which can replace a regular bipolar plate in the current state of the technology, can be used as monitoring tool and for targeted developments. This article gives an overview over the development and applications for proton exchange membrane fuel cell of this technology, such as water management or fault recognition. Recent advancements towards locally resolved monitoring of humidity and to current distributions in electrolysers are outlined.
ARTICLE | doi:10.20944/preprints202003.0058.v1
Online: 4 March 2020 (10:22:09 CET)
Objective:The Glioma brain tumor detection and segmentation methods are proposed in this paper using machine learning approaches. Methods:The boundary edge pixels are detected using Kirsch’s edge detectors and then contrast adaptive histogram equalization method is applied on the edge detected pixels. Then, Ridgelet transform is applied on this enhanced brain image in order to obtain the Ridgelet multi resolution coefficients. Further, features are derived from the Ridgelet transformed coefficients and the features are optimized using Principal Component Analysis (PCA) method and these optimized features are classified into Glioma or non-Glioma brain images using Co-Active Adaptive Neuro Fuzzy Expert System (CANFES) classifier.Results:The proposed method with PCA and CANFES classification approach obtains 97.6% of se, 98.56% of sp, 98.73% of Acc, 98.85% of Pr, 98.11% of FPR and 98.185 of FNR, then the proposed Glioma brain tumor detection method using CANFES classification approach only.
Tue, 3 March 2020
ARTICLE | doi:10.20944/preprints202003.0041.v1
Subject: Engineering, Industrial & Manufacturing Engineering Keywords: ultrasonic wave; microwave; instant green tea; extraction rate; active components; aroma
Online: 3 March 2020 (11:38:20 CET)
The production of instant green tea requires hot-water extraction, which is time consuming and contributes to losses in aromatic compounds. In this study, an ultrasonic-assisted technology was used to improve the extraction efficiency of green tea, thereby shortening extraction time from 45 to 15 min. In pure water, the dissolution of caffeine and theanine did not change significantly, but total catechin dissolution increased by 0.23 mg/mL and total tea polyphenol dissolution decreased by 3.2 mg/mL. In 76.2% ethanol, the dissolution of caffeine and theanine did not change significantly, but total catechin dissolution increased by 1.57mg/mL and total tea polyphenol dissolution decreased by 1.5 mg/mL. Additionally, we used microwave-assisted technology to further improve the extraction efficiency of green tea, which shortened the extraction time to 2 min. However, the extraction rate remained unchanged. In pure water, the dissolution of caffeine and theanine did not change significantly, but the dissolution of total catechins increased by 0.41 mg/mL and the dissolution of tea polyphenols decreased by 2.9 mg/mL. Ultrasonic treatment increased the proportion of 3-hydroxybutan-2-one, (5S)-5-(hydroxymethyl)oxolan-2-one and 2-phenylethanol, which were the main aroma compounds in tea. Microwave treatment changed the aroma compounds in tea, causing losses in aroma compounds with low boiling point and maintaining (5S)-5-(hydroxymethyl)oxolan-2-one. The taste and aroma of instant green tea improved based on sensory evaluation results.
ARTICLE | doi:10.20944/preprints202003.0036.v1
Subject: Engineering, Biomedical & Chemical Engineering Keywords: ECG feature selection; heartbeat classification; arrhythmia detection; random forest classifier
Online: 3 March 2020 (11:12:20 CET)
Finding an optimal combination of features and classifier is still an open problem in the development of automatic heartbeat classification systems, especially when applications that involve resource-constrained devices are considered. In this paper, a novel study of the selection of informative features and the use of a random forest classifier while following the recommendations of the Association for the Advancement of Medical Instrumentation (AAMI) and an inter-patient division of datasets is presented. Features were selected using a filter method based on the mutual information ranking criterion on the training set. Results showed that normalized R-R intervals and features relative to the width of the QRS complex are the most discriminative among those considered. The best results achieved on the MIT-BIH Arrhythmia Database were an overall accuracy of 96.14% and F1-scores of 97.97%, 73.06%, and 90.85% in the classification of normal beats, supraventricular ectopic beats, and ventricular ectopic beats respectively. In comparison with other state of the art approaches tested under similar constraints, this work represents one of the highest performances reported to date while relying on a very small feature vector.
Mon, 2 March 2020
ARTICLE | doi:10.20944/preprints202003.0031.v1
Subject: Engineering, Mechanical Engineering Keywords: Friction damper; Coating; Damping capacity; Fretting-wear
Online: 2 March 2020 (15:42:09 CET)
The concept of friction damper is widespread technique and used to reduce the structural vibrations in many industrial applications. These friction dampers are generally coated with low wear rate materials to reduce the fretting wear. This paper investigates the use of physical vapor deposition (PVD) nitride based AlTiN coating material applied over the stainless steel friction damper to enhance the damping capacity and to reduce the fretting wear. A friction test rig has been developed to measure the dynamic hysteresis characteristics of friction damper at high temperature (700 °C). The damping capacity and fretting wear analysis is carried out at room temperature, 300 °C and 600 °C. The force versus displacment characterisitcs curve is used to predict the damping capacity and fretting wear analysis is carried out at microscopic level for the comparision. It is observed that at room temperature AlTiN coated friction damper has not much influence to improve the damping capacity and to reduce the fretting-wear. However, at high temperature it has better damping capacity and less wear in comparision to uncoated friction damper. Wear behaviour in coated and uncoated damper is different at room temperature and at elevated temperature.
ARTICLE | doi:10.20944/preprints202003.0028.v1
Subject: Engineering, Energy & Fuel Technology Keywords: photovoltaic; energy yield; output forcasting; aerosol optical depth; precipitable water; incident angle
Online: 2 March 2020 (15:22:46 CET)
The outdoor field test of the 4-terminal III-V on Si tandem photovoltaic module (specifically, InGaP/GaAs on Si) was investigated and performance model, considering spectrum change affected by fluctuation of atmospheric parameters, was developed and validated. The 4-terminal III-V on Si tandem photovoltaic module had about 40 % advantage in seasonal performance loss compared with standard InGaP/GaAs/InGaAs 2-terminal tandem photovoltaic module. This advantage is expanded in (subarctic zone) < (temperate zone) < (subtropical zone).
ARTICLE | doi:10.20944/preprints202003.0018.v1
Subject: Engineering, Electrical & Electronic Engineering Keywords: visual-inertial integrated navigation system (VINS); visual odometry; autonomous driving; adaptive tuning; urban canyons
Online: 2 March 2020 (00:38:17 CET)
Visual-inertial integrated navigation system (VINS) has been extensively studied over the past decades to provide accurate and low-cost positioning solutions for autonomous systems. Satisfactory performance can be obtained in an ideal scenario with sufficient and static environment features. However, there are usually numerous dynamic objects in deep urban areas, and these moving objects can severely distort the feature tracking process which is fatal to the feature-based VINS. The well-known method mitigates the effects of dynamic objects is to detect the vehicles using deep neural networks and remove the features belongs to the surrounding vehicle. However, excessive exclusion of features can severely distort the geometry of feature distribution, leading to limited visual measurements. Instead of directly eliminating the features from dynamic objects, this paper proposes to adopt the visual measurement model based on the quality of feature tracking to improve the performance of VINS. Firstly, a self-tuning covariance estimation approach is proposed to model the uncertainty of each feature measurements by integrating two parts: 1) the geometry of feature distribution (GFD), 2) the quality of feature tracking. Secondly, an adaptive M-estimator is proposed to correct the measurement residual model to further mitigate the impacts of outlier measurements, such as the dynamic features. Different from the conventional M-estimator, the proposed method effectively alleviates the reliance of excessive parameterization of M-estimator. Experiments are conducted in a typical urban area of Hong Kong with numerous dynamic objects, and the results show that the proposed method could effectively mitigate the effects of dynamic objects and improved accuracy of VINS is obtained when compared with the conventional method.
Sun, 1 March 2020
ARTICLE | doi:10.20944/preprints202003.0015.v1
Subject: Engineering, Mechanical Engineering Keywords: 316L austenitic steel; selective laser melting; powder bed fusion; technological parameters; mechanical property characterization
Online: 1 March 2020 (15:36:32 CET)
The main aim of this study is to investigate the optimization of the technological process for selective laser melting (SLM) additive manufacturing. The group of process parameters considered was selected from the first-stage parameters identified in preliminary research. Samples manufactured using three different sets of parameter values were subjected to static tensile and compression tests. The samples were also subjected to dynamic Split–Hopkinson tests. To verify the microstructural changes after the dynamic tests, microstructural analyses were conducted. Additionally, the element deformation during the tensile tests was analyzed using digital image correlation (DIC). To analyze the influence of the selected parameters and verify the layered structure of the manufactured elements, sclerometer scratch hardness tests were carried out on each sample. Basing on the research results it was possible to observe the porosity growth mechanism and its influence on the material strength (including static and dynamic tests). Parameters modifications that caused 20% lower energy density, elongation of the elements during tensile testing decreased twice, which was strictly connected with porosity growth. An increase of energy density by almost three times caused a significant reduction of force fluctuations differences between both tested surfaces (parallel and perpendicular to the building platform) during sclerometer hardness testing. That kind of phenomenon had been taken into account in the microstructure investigations before and after dynamic testing where it had been spotted a positive impact on material deformations based on fused material grains formation after SLM processing.
ARTICLE | doi:10.20944/preprints202003.0012.v1
Subject: Engineering, Construction Keywords: Building Information Modelling (BIM); Life-Cycle Assessment (LCA); Building process; Level of Development (LOD); Embodied environmental impacts; Greenhouse Gas emissions (GHG); LCA databases; LCA values; LCA benchmarks; cost estimation structure
Online: 1 March 2020 (13:16:52 CET)
The building sector has a big potential to reduce the material resource demand needed for building construction and therefore, greenhouse gas (GHG) emissions. Digitalisation can help to make use of this potential and improve sustainability throughout the entire building’s life cycle. One way to address this potential is through the integration of Life-Cycle Assessment (LCA) into the building process by employing Building Information Modelling (BIM). BIM can reduce the effort needed to carry out an LCA and therefore facilitate the integration into the building process. A review of current industry practice and scientific literature shows two main approaches to address BIM-LCA integration. Either the LCA is performed in a simplified way at the beginning of the building process, or it is done at the very end when all the needed information is available, but it is too late for decision-making. One reason for this is the lack of methods, workflows and tools to implement BIM-LCA integration over the entire building process. Therefore, the main objective of this study is to develop an integrated BIM-LCA workflow implemented into a method for the whole building process using an existing structure for cost estimation. A tool is created and used in a case study in Switzerland to test the developed approach. The results of this study show that LCA can be performed continuously in each building phase over the entire building process using existing BIM modelling techniques. The main benefit of this approach is that the re-work caused by the need for re-entering data and the usage of many different software tools that characterise most of the current LCA practices is minimised. Furthermore, decision-making, both at the element and building levels, is supported.
ARTICLE | doi:10.20944/preprints202003.0006.v1
Subject: Engineering, Civil Engineering Keywords: plastic waste; concrete waste; recycling; heat pressing
Online: 1 March 2020 (03:24:14 CET)
Demolished concrete and plastic waste are two increasingly aggravating problems. In this study, a novel method was proposed to simultaneously recycle concrete and plastic wastes by compacting concrete and plastic powders together under pressure and temperature. The influence of compression pressure and temperature as well as the mixture proportion on the bending strength of specimens was investigated. The results showed that pressure and temperature had a positive effect on the specimen strength; however, the molding temperature should not exceed the melting temperature of plastic. The proportion of plastic had a minimal effect on the bending strength of the specimen when plastic accounted for 25%–75% of the overall mass of the test piece.
Sat, 29 February 2020
ARTICLE | doi:10.20944/preprints202002.0460.v1
Subject: Engineering, Electrical & Electronic Engineering Keywords: digital metamaterial; liquid crystal (LC); coding particle; beam steering; RCS reduction; beam shaping
Online: 29 February 2020 (09:32:31 CET)
This paper presents a multifunctional reflective digital metasurface of arbitrary base based on voltage tunable liquid crystal (LC). The reflective digital metamaterial can be multiplexed for different desirable functions by properly biasing the LC for different code patterns. Simulation results of three significant functions, beam steering with a steering elevation angle 27° at 75 GHz, RCS reduction of at least 15dB along the incident direction, and beam shaping with different beam shapes have been presented to prove the concept.
ARTICLE | doi:10.20944/preprints202002.0459.v1
Subject: Engineering, Energy & Fuel Technology Keywords: low concentration; gas; reactor; high-temperature oxidation
Online: 29 February 2020 (09:20:28 CET)
To achieve efficient utilization of low-concentration mine gas, reduce resource waste, and alleviate environmental pollution, high-temperature oxidation of low-concentration gas at a concentration range of 1.00% to 1.50% that is directly discharged into the atmosphere during coal mine production was oxidized to recover heat for reuse. The gas oxidation equipment was improved for the heating process, and the safety of low-concentration gas oxidation under high-temperature environment was evaluated. Experimental results showed that the reactor could provide a 1000 ℃ high-temperature oxidation environment for gas oxidation after installing high-temperature resistant ceramics. The pressure variation curves of the reactor with air and different concentrations of gas were similar. Due to the thermal expansion, the air pressure slightly increased and then returned to normal pressure. In contrast, the low-concentration gas exhibited a stable pressure response in the high-temperature environment of 1000 ℃. The outlet pressure was significantly greater than the inlet pressure, and the pressure difference between the inlet and outlet exhibited a trend to increase with the gas concentration. The explosion limit varied with the temperature and the blend with oxidation products. The ratio of measured gas pressure to air pressure after oxidation was below the explosion criterion, indicating that the measured concentration gas is still safe after the shift of explosion limit, which provides a safe concentration range for efficient use of low-concentration gas in the future.
ARTICLE | doi:10.20944/preprints202002.0457.v1
Subject: Engineering, Industrial & Manufacturing Engineering Keywords: diffusion welding; diffusion bonding; cross section width; aspect ratio; material thickness; thermocouple aging
Online: 29 February 2020 (09:01:14 CET)
Diffusion bonding is often used on pre-machined parts to generate internal cavities, e.g. for cooling injection molding tools close to the mold cavity. Only then, the workpieces are finished to their final dimensions. In the case of micro-process devices, however, it is essential to precisely control the deformation, as otherwise uncontrollable pressure losses will occur with channel cross-sections in the sub-millimeter range. Post-processing is not possible. The most important process parameters for diffusion bonding are temperature, dwell time and contact pressure, with the bonding temperature and contact pressure acting in opposite directions and showing a strong non-linear dependence on deformation. In addition, the deformation is influenced by a number of other factors such as the absolute size of the cross-section and the aspect ratio of the parts, the dimensions and distribution of the internal cross sections and the overall percentage of the cross-section to be bonded. In micro process engineering, small material cross-sections in the range of the materials microstructure can facilitate additional deformation mechanisms such as grain boundary sliding, which are not relevant at all for larger structures. For parts consisting of multiple layers, tolerances in thickness and roughness of multiple surfaces must be levelled, contributing to the percentaged deformation. This makes it difficult, especially in micro process engineering and in single or small series production, to determine suitable joining parameters in advance, which on the one hand do not cause unforeseen large deformations, but on the other hand reliably produce highly vacuum-tight components. Hence, a definition of a fixed percentaged deformation does not work for all kinds of components. This makes it difficult to specify parameters for surely obtain high-vacuum tight parts. For successful diffusion bonding, atoms must diffuse over the bonding planes, forming a monolithic part in which the original layers are no longer visible. Only then, mechanical properties identical to those of the base material, which has been subjected to identical heat treatment, can be achieved. In this paper, the impacts of different material cross section widths as well as of the aspect ratio on deformation were investigated. By accident, it was found that also accuracy of the temperature measurement may have a serious impact in terms of deformation.
Fri, 28 February 2020
ARTICLE | doi:10.20944/preprints202002.0441.v1
Subject: Engineering, Electrical & Electronic Engineering Keywords: Paper based sensor; whole virus; Zika; Aptamer
Online: 28 February 2020 (13:30:18 CET)
Paper-based sensors, microfluidic platforms and electronic devices have attracted attention in the past couple of decades because they are flexible, can be recycled easily, environmentally friendly, and inexpensive. Here we report a paper aptamer-based potentiometric sensor to detect the whole Zika virus for the first time with a minimum sensitivity of 2.6 nV/Zika and the minimum detectable signal (MDS) of 0.8x1e6 Zika. Our paper sensor works very similar to a P-N junction where a junction is formed between two different wet regions with different electrochemical potentials near each other on the paper. These two regions with slightly different ionic contents, ionic species and concentrations, produce a potential difference given by the Nernst equation. Our paper sensor consisted of a 2-3 mm x 10 mm segments of a paper with a conducting silver paint contact patches on its two ends. The paper is soaked in a buffer solution containing aptamers designed to bind to the capsid proteins on Zika. Atomic force microscopy studies were carried out to show both the aptamer and Zika become immobilized in the paper. We then added the Zika (in its own buffer or simulant Urine) to the region close to one of the silver-paint contacts. The Zika virus (40 nm diameter with 43 kDa or 7.1x10-20 gm weight), became immobilized in the paper’s pores and bonded with the resident aptamers creating a concentration gradient. The potential measured between the two silver paint contacts reproducibly became more negative as upon adding the Zika. We also showed that an LCD powered by the sensor, can be used to detect the sensor output.
Subject: Engineering, Industrial & Manufacturing Engineering Keywords: fibres; composites; discontinuous; surfactants
Online: 28 February 2020 (13:24:19 CET)
In order to increase the material throughput of aligned discontinuous fibre composites using technologies such as HiPerDiF, stability of the fibres in an aqueous solution needs to be achieved. Subsequently, a range of surfactants, typically employed to disperse carbon-based materials, have been assessed to determine the most appropriate for use in this regard. The optimum stability of the discontinuous fibres was observed when using the anionic surfactant, sodium dodecylbenzene sulfonate, which was superior to a range of other non-ionic and anionic surfactants and single-fibre fragmentation demonstrated that the employment of sodium dodecylbenzene sulfonate did not effect on the interfacial adhesion between fibres. The use of rheometry was used to complement the study to understand the potential mechanisms of the improved stability of discontinuous fibres in aqueous suspension and it led to the understanding that the increased viscosity was a significant factor. For the shear rates employed, fibre deformation was neither expected nor observed.
ARTICLE | doi:10.20944/preprints202002.0434.v1
Subject: Engineering, Mechanical Engineering Keywords: acoustic levitation; ultrasonic phased array; droplet; coalescence; lab-on-a-drop
Online: 28 February 2020 (13:02:22 CET)
The contactless coalescence of a droplet is of paramount importance for physical and industrial applications. This paper describes a coalescence method in mid-air via acoustic levitation using an ultrasonic phased array system. Acoustic levitation using ultrasonic phased arrays provides promising lab-on-a-drop applications, such as transportation, coalescence, mixing, separation, evaporation, and extraction in a continuous operation. The mechanism of droplet coalescence in mid-air may be better understood by experimentally and numerically exploring the droplet dynamics immediately before the coalescence. In this study, water droplets were experimentally levitated, transported, and coalesced by controlling acoustic fields. We observed that the edge of droplets deformed and attracted each other immediately before the coalescence. Through image processing, the radii of curvature of the droplets were quantified and the pressure difference between the inside and outside the droplet was simulated to obtain the pressure and velocity information on the droplet surface. The results revealed that the sound pressure acting on the droplet clearly decreased before the impact of the droplets. This pressure on the droplets was quantitatively analyzed from the experimental data. Our experimental and numerical results provide deeper physical insights into contactless droplet manipulation for futuristic lab-on-a-drop applications.
ARTICLE | doi:10.20944/preprints202002.0428.v1
Subject: Engineering, Civil Engineering Keywords: small hydropower plant; river flow; seasonal forecast; energy production
Online: 28 February 2020 (12:15:43 CET)
The operation feasibility of small hydropower plants in mountainous sites is subjected to the run-of-river flow which is also depending on a high variability in precipitation and snow cover. Moreover, the management of this kind of systems has to be performed with some particular operation conditions of the plant (e.g. turbine minimum and maximum discharge) but also some environmental flow requirements. In this context, a technological climate service is conceived in tight connection with end users, perfectly answering the needs of the management of small hydropower systems in a pilot area, and providing forecast of river streamflow together with other operation data. This paper presents an overview of the service but also a set of lessons learnt related to features, requirements and considerations to bear in mind from the point of view of climate services developers. In addition, the outcomes give insight into how this kind of services could change the traditional management (normally based on the past experience), providing a probability range of future river flow based on future weather scenarios according to the range of future weather possibilities. This highlights the utility of the co-generation process to implement climate services for water and energy fields but also that seasonal climate forecast could improve the business as usual of this kind of facilities.
ARTICLE | doi:10.20944/preprints202002.0426.v1
Subject: Engineering, Electrical & Electronic Engineering Keywords: IEEE 802.15.4g, Smart Utility Networks; Low-Power; Wireless; Modulation Diversity; Reliability; Availability
Online: 28 February 2020 (12:08:40 CET)
The IEEE 802.15.4-2015 standard includes the SUN (Smart Utility Networks) modulations, i.e., SUN-FSK, SUN-OQPSK and SUN-OFDM, which provide long range communications and allow to trade data rate, occupied bandwidth and reliability. However, given the constraints of low-power devices and the challenges of the wireless channel, communication reliability cannot still meet the PDR (Packet Delivery Ratio) requirements of industrial applications, i.e., PDR>99%. Hence, in this paper we evaluate the benefits of improving communication reliability by combining packet transmissions with modulation diversity using multiple IEEE 802.15.4g SUN modulations. The results derived from a real-world deployment show that going from 1 to 3 packet transmissions with the same SUN modulation can increase PDR from 85.0/84.6/71.3% to 94.2/94.1/86.0% using SUN-FSK, SUN-OQPSK and SUN-OFDM, respectively. Combining the same number of packet transmissions with modulation diversity allows to further increase the average PDR to 97.1%, indicating its potential as a tool to help meeting the reliability requirements of industrial applications.
ARTICLE | doi:10.20944/preprints202002.0422.v1
Subject: Engineering, Biomedical & Chemical Engineering Keywords: inertial spiral microfluidics; dendritic cell separation; resource-limited microfluidics
Online: 28 February 2020 (11:54:44 CET)
Microfluidics technology has not impacted the delivery and accessibility of point of care health services like diagnosis of infectious disease diagnosis, monitoring health or delivering interventions. Most microfluidics prototypes from academic research are not easy to manufacture with industrial scale fabrication techniques and cannot be operated without complex manipulations of supporting equipment and additives such as labels or reagents. We propose a label- and reagent-free inertial spiral microfluidic device to separate red blood, white blood and dendritic cells from blood fluid for applications in health monitoring and immunotherapy. We demonstrate that using larger channel widths in the range of 200 to 600 µm allows separation of cells into multiple streams according to different size ranges and we utilize a novel technique to collect the closely separated focused cell streams without constricting the channel. When tested on actual human blood cells, 77% of dendritic cells were separated and 80% of cells remained viable after our assay. Our contribution is a method to adapt spiral inertial microfluidic designs to separate more than two cell types in the same device which is robust against clogging, simple to operate and suitable for fabrication and deployment in resource-limited populations.
ARTICLE | doi:10.20944/preprints202002.0415.v1
Subject: Engineering, Biomedical & Chemical Engineering Keywords: electromyography; EMG; feature extraction; feature selection; myoelectric control; classification; pattern recognition; prosthetics; wearables; amputee
Online: 28 February 2020 (02:09:05 CET)
Myoelectric control is the cornerstone of many assistive technologies used in clinical practice, such as prosthetics and orthoses, and human-computer interaction, such as virtual reality control. Although the performance of such devices exceeds 90\% in controlled environments, myoelectric devices still face challenges in robustness to variability of daily living conditions. Within this survey, the intrisic physiological mechanisms limiting practical implementations of myoelectric devices were explored: the limb position effect and the contraction intensity effect. The degradation of electromyography (EMG) pattern recognition in the presence of these factors was demonstrated on six datasets, where performance was 13% and 20% lower in realistic environments compared to controlled environments for the limb position and contraction intensity effect, respectively. The experimental designs of limb position and contraction intensity literature were surveyed. Current state-of-the-art training strategies and robust algorithms for both effects were compiled and presented. Recommendations for future limb position effect studies include: the collection protocol providing exemplars of 6 positions (four limb positions and three forearm orientations), three-dimensional space experimental designs, transfer learning approaches, and multi-modal sensor configurations. Recommendations for future contraction intensity effect studies include: the collection of dynamic contractions, nonlinear complexity features, and proportional control.
ARTICLE | doi:10.20944/preprints202002.0413.v1
Subject: Engineering, Energy & Fuel Technology Keywords: geothermal energy; life cycle analysis; solar photovoltaic energy; wind energy
Online: 28 February 2020 (01:34:44 CET)
A Life Cycle Analysis was performed considering three existing power plants of comparable size operating with different sources of renewable energy: geothermal, solar and wind. Primary data were used for building the life cycle inventories. The geothermal power plant includes emissions treatment for removal of hydrogen sulfide and mercury. The scenario about the substitution of natural emissions from geothermal energy, with specific reference to the greenhouse effect, is also investigated performing a sensitivity analysis. The results are characterized employing a wide portfolio of environmental indicators employing the Recipe 2016 and the ILCD 2011 Midpoint+ methods; normalization and weighting are also applied using the Recipe 2016 method at endpoint level. The results demonstrate a good eco-profile of geothermal power plant with respect to other renewable energy systems and allow for a critical analysis to support potential improvements of the environmental performances.
Thu, 27 February 2020
ARTICLE | doi:10.20944/preprints202002.0411.v1
Subject: Engineering, Civil Engineering Keywords: transportation infrastructure; flexible pavement; structural number prediction; Gaussian process regression; m5p model tree; random forest
Online: 27 February 2020 (16:08:35 CET)
The most common index for representing structural condition of the pavement is the structural number. The current procedure for determining structural numbers involves utilizing falling weight deflectometer and ground-penetrating radar tests, recording pavement surface deflections, and analyzing recorded deflections by back-calculation manners. This procedure has two drawbacks: 1. falling weight deflectometer and ground-penetrating radar are expensive tests, 2. back-calculation ways has some inherent shortcomings compared to exact methods as they adopt a trial and error approach. In this study, three machine learning methods entitled Gaussian process regression, m5p model tree, and random forest used for the prediction of structural numbers in flexible pavements. Dataset of this paper is related to 759 flexible pavement sections at Semnan and Khuzestan provinces in Iran and includes “structural number” as output and “surface deflections and surface temperature” as inputs. The accuracy of results was examined based on three criteria of R, MAE, and RMSE. Among the methods employed in this paper, random forest is the most accurate as it yields the best values for above criteria (R=0.841, MAE=0.592, and RMSE=0.760). The proposed method does not require to use ground penetrating radar test, which in turn reduce costs and work difficulty. Using machine learning methods instead of back-calculation improves the calculation process quality and accuracy.
Wed, 26 February 2020
ARTICLE | doi:10.20944/preprints202002.0394.v1
Subject: Engineering, Mechanical Engineering Keywords: Dimensionless number; Similarity; Scaling; Geometric distortion; Structural impact
Online: 26 February 2020 (12:28:04 CET)
A framework of similarity laws, termed oriented-density-length-velocity (ODLV) framework, is suggested for the geometric distorted structures subjected to impact loading. The distinct feature of this framework is that the newly proposed oriented dimensions, dimensionless numbers and scaling factors for physical quantity are explicitly expressed by the characteristic lengths of three spatial directions, which overcome the inherent defects that traditional scalar dimensional analysis could not express the effects of structural geometric characteristics and spatial directions for similarity. The non-scalabilities of geometrical distortion as well as other distortions such as different materials and gravity could be compensated by the reasonable correction for the impact velocity, the geometrical thickness and the density, when the proposed dimensionless number of equivalent stress is used between scaled model and prototype. Three analytical models of beam, plate and shell subjected to impact mass or impulsive velocity are verified by equation analysis. And a numerical model of circular plate subjected to dynamic pressure pulse is verified in more detail, form the view of point of space deformation, deformation history and the components of displacement, strain and stress. The results show that the proposed dimensionless numbers have attractively perfect ability to express the dimensionless response equations of displacement, angle, time, strain and strain rate. When the proposed dimensionless numbers are used to regularize impact models, the structural responses of the geometrically distorted scaled models can behave the completely identical behaviors with those of the prototype on space and time —not only for the direction-independent equivalent stress, strain and strain rate but also for the direction-dependent displacement, stress and strain components.
ARTICLE | doi:10.20944/preprints202002.0392.v1
Subject: Engineering, Electrical & Electronic Engineering Keywords: power converter; fault diagnosis; intelligent algorithm; variational mode decomposition; deep belief network
Online: 26 February 2020 (11:25:27 CET)
The power converter is the significant device in a wind power system. Wind turbine will be shut down and off grid immediately with the occurrence of the IGBT module open-circuit fault of power converter, which will seriously impact the stability of grid and even threaten personal safety. However, in the existing diagnosis strategies of power converter, there are few single and double IGBT modules open-circuit fault diagnosis methods producing negative results including erroneous judgment, omissive judgment and low accuracy. In this paper, a novel method to diagnose the single and double IGBT modules open-circuit faults of the permanent magnet synchronous generator (PMSG) wind turbine grid-side converter (GSC) is proposed. Above all, collecting the three-phase current varying with wind speed of 22 failure states including a normal state of PMSG wind turbine GSC as the original signal data. Afterward, the original signal data are decomposed by using variational mode decomposition (VMD) to obtain the mode coefficient series, which are analyzed by the proposed method base on fault trend feature for extracting the trend feature vectors. Finally, the trend feature vectors are used as the input of deep belief network (DBN) for decision-making and obtaining the classification results. The simulation and experimental results show that the proposed method can diagnose the single and double IGBT modules open-circuit faults of GSC, and the accuracy is higher than the benchmark models.
ARTICLE | doi:10.20944/preprints202002.0390.v1
Subject: Engineering, Mechanical Engineering Keywords: proper orthogonal decomposition; wind farms; eigenspectra; counter-rotating roll cells
Online: 26 February 2020 (11:09:26 CET)
Large scale coherent structures in atmospheric boundary layer (ABL) are known to contribute to the power generation in wind farms. In the current paper, we perform a detailed analysis of the large scale structures in a finite sized wind turbine canopy using modal analysis from three dimensional proper orthogonal decomposition (POD). While POD analysis sheds light on the large scale coherent modes and scaling laws of the eigenspectra, we also observe a slow convergence of the spectral trends with the available number of snapshots. Since the finite sized array is periodic in the spanwise direction, we propose to adapt a novel approach of performing POD analysis of the spanwise/lateral Fourier transformed velocity snapshots instead of the snapshots themselves. This methodology not only helps in decoupling the length scales in the spanwise and the streamwise direction when studying the energetic coherent modes, but also provides a detailed guidance towards understanding the convergence of the eigenspectra. In particular, the Fourier-POD eigenspectra helps us illustrate if the dominant scaling laws observed in 3D POD are actually contributed by the laterally wider or thinner structures and provide more detailed insight on the structures themselves. We use the database from our previous large eddy simulation (LES) studies on finite-sized wind farms which uses wall-modeled LES for modeling the Atmospheric boundary layer laws, and actuator lines for the turbine blades. Understanding the behaviour of such structures would not only help better assess reduced order models (ROM) for forecasting the flow and power generation but would also play a vital role in improving the decision making abilities in wind farm optimization algorithms in future. Additionally, this study also provides guidance for better understanding the POD analysis in the turbulence and wind farm community.
ARTICLE | doi:10.20944/preprints202002.0387.v1
Subject: Engineering, Energy & Fuel Technology Keywords: hydrothermal energy; river-water heat pump; water temperature recovery distance; heat transfer equation; Environmental Fluid Dynamic Code (EFDC); Han river basin
Online: 26 February 2020 (02:58:42 CET)
Temperature differences between the atmosphere and river water allow rivers to be used as a hydrothermal energy source. The river-water heat pump system is a relatively non-invasive renewable energy source; however, effluent discharged from the heat pump can cause downstream temperature changes which may impact sensitive fluvial ecosystems. In this study, the water temperature recovery distance of the effluent was estimated for a river section in the Han River Basin, Korea, using the heat transfer equation and the Environmental Fluid Dynamic Code (EFDC) model. Results showed that, compared to the EFDC model, the heat transfer equation tended to overestimate the water temperature recovery distance due to its simplified assumptions. The water temperature recovery distance could also be used as an objective indicator to decide the reuse of downstream river water. Furthermore, as the river system was found to support an endangered fish species that is sensitive to water environment changes, care should be taken to exclude the habitats of protected species affected by water temperatures within water temperature recovery distance.
ARTICLE | doi:10.20944/preprints202002.0384.v1
Subject: Engineering, Mechanical Engineering Keywords: sweeping jet actuator; jet oscillation frequency; compressibility effect; unsteady Reynolds–Averaged Navier–Stokes; mass flow rate
Online: 26 February 2020 (02:17:51 CET)
The time-resolved flowfield of a spatially oscillating jet emitted by a Sweeping Jet (SWJ) actuator is investigated numerically using three-dimensional Reynolds-averaged Navier-Stokes (3D-URANS) equations. Numerical simulations are performed for a practical range of mass flow rates providing flow conditions ranging from incompressible to subsonic compressible flows. A linear relationship between the mass flow rate and the jet oscillation frequency is found. The results of the numerical model are compared with the experimental data in the literature, and good agreement is found. Additionally, it is observed that the SWJ actuator frequency response switches from one linear mode to another linear mode when the compressibility effects become important.
Tue, 25 February 2020
ARTICLE | doi:10.20944/preprints202002.0371.v1
Subject: Engineering, Civil Engineering Keywords: beam-like model; dynamic analysis; Rayleigh-Ritz; shear torsional beam; FEM models
Online: 25 February 2020 (11:20:49 CET)
Dynamic analyses and seismic assessments of multi-storey buildings at urban level require large-scale simulations and computational procedures based on simplified but accurate numerical models. At this aim the present paper propos-es an equivalent non-uniform beam-like model, suitable for the dynamic analysis of buildings with asymmetric plan and non-uniform vertical distribution of mass and stiffness. The equations of motion of this beam-like model, which pre-sents only shear and torsional deformability, are derived through the application of Hamilton’s principle. The linear dy-namic behaviour is evaluated by discretizing the continuous non-uniform model according to a Rayleigh-Ritz approach based on a suitable number of modal shapes of the uniform shear-torsional beam. In spite of its simplicity, the model is able to reproduce the dynamic behaviour of low- and mid-rise buildings with a significant reduction of the computa-tional burden with respect to that required by more general models. The efficacy of the proposed approach has been tested, by means of comparisons with linear FEM simulations, on three multi-storey buildings characterized by different irregularities. The satisfactory agreement, in terms of natural frequencies, modes of vibration and seismic response, proves the capability of the proposed approach to reproduce the dynamic response of complex spatial multi storey frames.
ARTICLE | doi:10.20944/preprints202002.0369.v1
Subject: Engineering, Energy & Fuel Technology Keywords: Solar Cooling; Adsorption; Evacuated tube collectors; Experimental testing
Online: 25 February 2020 (11:12:51 CET)
The high environmental impact of conventional methods of cooling and heating has increased the need for renewable energy deployment for covering thermal loads. Towards that direction, the proposed system aims at offering an efficient solar powered alternative, coupling a zeolite-water adsorption chiller with a conventional vapor compression cycle. The system is designed to operate under intermittent heat supply of low-temperature solar thermal energy (<90 °C) provided by evacuated tube collectors. A prototype was developed and tested in cooling mode operation. The results of separate components testing showed that the adsorption chiller was operating efficiently, achieving a maximum coefficient of performance (COP) of 0.65. With respect to the combined performance of the system, evaluated on a typical week of summer in Athens, the maximum reported COP was approximately 0.575, mainly due to the lower driving temperatures at a range of 75 °C. The corresponding mean energy efficiency ratio (EER) obtained was 5.8.
ARTICLE | doi:10.20944/preprints202002.0368.v1
Subject: Engineering, Civil Engineering Keywords: Aridity Index (AI); Percentage of Normal Index (PNI); Standardized Precipitation -Evopotranspiration Index (SPEI); Standardized Precipitation Index (SPI); Drought; Factor Analysis; Reliability Analysis
Online: 25 February 2020 (11:09:28 CET)
The climate covers a series of events that deeply affect human life. It is possible to understand these events through spatial and statistical analyzes. Today, climate change, which is one of the most important of these events and the impact factors of consequences of this change, become a current issue. Drought is cited as one of the consequences of climate change and it is important to examine it with various methods as it can give negative results to both the economy and the nature. In this study, the drought status of the regions where these stations are located and the effects of drought on climate change were statistically calculated and evaluated using Standardized Precipitation Index (SPI), Percentage of Normal Index (PNI), Aridity Index (AI) and Standardized Precipitation -Evopotranspiration Index (SPEI). The precipitation data from 1981 to 2010 were obtained from Cihanbeyli, Karapınar, Çumra, Seydişehir, Kulu, Ereğli, Niğde, Karaman, Beyşehir and Aksaray meteorology stations affiliated to Turkish State Meteorological Service. At the same time, factor analysis and validity-reliability analysis were conducted to test the computability of the indices used in the study as a single index and to determine the reliability of the operations. While using exploratory factor analysis, Kaiser-Meyer-Olkin (KMO) test and Barlett test for factor analysis; Cronbach's alpha coefficient was used for reliability analysis. In our study, K-Means Cluster Analysis method was performed to determine the cutoff values of indices. According to the result of cluster analysis for the new (common) index, new clusters were created and ANOVA test was conducted to determine whether there was a difference between clusters.
Mon, 24 February 2020
Subject: Engineering, Industrial & Manufacturing Engineering Keywords: Hydrostatic; Blade guides; Bandsaw; Diamond blade; Natural stone; Sawing
Online: 24 February 2020 (12:23:56 CET)
In a bandsaw machine the blade guides provide additional stiffness and help to align the blade near the cutting region. Typically these are either in form of blocks made of carbide or ceramics or as sealed bearings. Abrasive particles, generated while cutting hard and brittle materials like natural stones, settle between the contact surfaces of the guides and the blade causing wear and premature failure. The hydrostatic guide system as presented in this work, is a contactless blade guiding method that uses force of several pressurized water jets to align the blade to the direction of the cut. For this investigation, cutting tests were performed on a marble block using a galvanic diamond coated bandsaw blade with the upper roller guides replaced by hydrostatic guides. The results show that the hydrostatic guides help to reduce the passive force while cutting to a constant near zero in contrast to the traditional guides. This also resulted in reduced surface roughness of the stone plates that were cut indicating a reduction in lateral vibration of the band. Additionally, it has also been shown that using hydrostatic guides the bandsaw blade can be tilted to counter the bandsaw drift opening opportunities for further research in active alignment control. This original research work has shown that the hydrostatic guide systems are capable of replacing and in fact perform better than state of the art bearing or block guides particularly for stone cutting applications.
ARTICLE | doi:10.20944/preprints202002.0344.v1
Subject: Engineering, Civil Engineering Keywords: flow regime transition; finite volume methods; numerical oscillations; numerical viscosity; Preissmann slot model
Online: 24 February 2020 (03:38:08 CET)
Transition between free-surface and pressurized flows is an crucial phenomenon in many hydraulic systems, including water distribution systems, urban drainage systems, etc. During the transition, the force exerted on the structures changes drastically, thus it is meaningful to simulate this process. However, severe numerical oscillations are widely observed behind filling-bores, causing unphysical pressure variations and even computation failure. In this paper, some oscillation-suppressing approaches are reviewed and evaluated on a benchmark model. Then a new oscillation-suppressing approach is proposed to admit numerical viscosity when the water surface is at proximity of conduct roof which has first order accuracy. This approach adds numerical viscosity when water surface is at the proximity of conduct roof. It can sufficiently suppress numerical oscillations under an acoustic wave speed of 1000m/s and is simple to apply. In comparison with two experiments, the simulation results of this method show good agreement and little numerical oscillations. The results in this paper can help readers to choose an appropriate oscillation-suppressing method to improve the robustness and accuracy of flow regime transition simulations.
Sun, 23 February 2020
ARTICLE | doi:10.20944/preprints202002.0330.v1
Subject: Engineering, Electrical & Electronic Engineering Keywords: distributed generation; energy resource management; optimization; mixed-binary linear programming; smart buildings
Online: 23 February 2020 (15:30:01 CET)
Efficient alternatives in energy production and consumption are constantly investigated by increasingly strict policies. In this way, the pollutant emissions that contribute to the greenhouse effect reduce and sustainability of the electricity sector increase. With more than a third of the world's energy consumption, buildings have great potential to contribute these sustainability goals. Additionally, with growing incentives in the Distributed Generation (DG) and Electric Vehicle (EV) industry, it is believed that Smart Buildings (SBs) can be a key in the field of residential energy sustainability in the future. In this work, an energy management system in SBs are developed to reduce the power demanded of a residential building. In order to balance the demand and power provided by the grid, microgrids such as Battery Energy Storage System (BESS), EVs and Photovoltaic Generation panels (PV) are used. Here, a Mixed Binary Linear Programming formulation (MBLP) is proposed to optimize the charge and discharge scheduling of EVs and also BESS. In order to show the efficiency of the model, a case study involving three scenarios and an economic analysis is considered. The results point a 65% reduction in peak load consumption supplied by grid and a 28.4% reduction in electricity consumption costs.
ARTICLE | doi:10.20944/preprints202002.0314.v1
Subject: Engineering, Electrical & Electronic Engineering Keywords: phase load balancing; smart meters; dynamic optimization; on-line implementation; low voltage electric distribution networks
Online: 23 February 2020 (10:14:51 CET)
In the electric distribution systems, the “Smart Grid” concept is implemented to encourage energy savings and integration of the innovative technologies, helping the Distribution Network Operators (DNOs) in choosing the investment plans which to lead the optimal operation of the networks and increasing the energy efficiency. In this context, a new phase load balancing algorithm was proposed to be implemented in the low voltage distribution networks with hybrid structures of the consumption points (switchable and non-switchable consumers). It can work in both operation modes (on-line and off-line), uploading information from different databases of the DNO which contain: the consumers’ characteristics, the real loads of the consumers integrated into the Smart Metering System (SMS), and the typical load profiles for the consumers non-integrated in the SMS. The algorithm was tested in a real network, having a hybrid structure of the consumption points, on a time interval by 24 hours. The obtained results were analyzed and compared with other algorithms from the heuristic (Minimum Count of Loads Adjustment algorithm) and the metaheuristic (Particle Swarm Optimization and Genetic Algorithms) categories. The best performances were provided by the proposed algorithm, such that the unbalance coefficient resulted in the smallest value (1.0017). The phase load balancing led to the following technical effects: decreasing the average current in the neutral conductor with 94% and for the energy losses with 61.75 %, and increasing the minimum value of the phase voltage at the farthest pillar with the 7.14 %, compared to the unbalanced case.
ARTICLE | doi:10.20944/preprints202002.0312.v1
Subject: Engineering, Civil Engineering Keywords: recycling; concrete waste; wooden waste; heating compaction; bending strength
Online: 23 February 2020 (09:28:21 CET)
A large amount of concrete waste is generated around the world and its recycling is an urgent issue. In this research, a new approach to recycle concrete waste with wooden waste was studied. Concrete and wooden wastes were crushed, mixed, and heat compacted to produce plates with different water contents and mix proportions at various temperatures, pressures, and durations of compaction. The bending strength of the plates was measured after compaction. The result indicated that with an increase in the percentage of wooden waste in the mixture, pressure, or temperature improved the bending strength. The increase in water content reduced the bending strength. Most of the products exhibited higher bending strength than that of ordinary concrete.
Fri, 21 February 2020
Subject: Engineering, Marine Engineering Keywords: KPIs; offshore structural integrity; Bowtie; FAHP
Online: 21 February 2020 (07:42:14 CET)
Leading and lagging Key performance indicators (KPIs) provide a means for assurance that risk control systems, to prevent or limit major hazards. The relative importance degree of KPIs provides a theorical guidance for monitoring, inspection and maintenance of structural integrity. In this paper, structural integrity KPIs are classified into leading and lagging KPIs based on Bowtie methodology and the importance degree of the KPIs are evaluated by weight calculation on the basis of Fuzzy analytical hierarchy process (FAHP).
Subject: Engineering, Energy & Fuel Technology Keywords: photovoltaics; solar energy; Father Verspieren; solar energy in Africa; solar economy; solar pump
Online: 21 February 2020 (02:29:52 CET)
Almost fifty years after the first installations, I identify the main lessons learned from fighting drought and poverty in Africa with direct solar-powered pumps thanks to Father Bernard Verspieren and Mali Aqua Viva. Six main findings and three main recommendations emerge from the present analysis which are of direct relevance to all Africa’s countries whose population has gone from 438 million in 1977 to 1308 million in 2019, with about 600 million still having no access to electricity. In place of “awareness campaigns”, I recommend to organize practice-oriented workshops on solar-powered irrigation and rainwater harvesting held by professional educators of newly established solar energy national institutes. In agreement with today’s expanded approach to education in solar energy, and with the key adult learning principle of motivation to learn, said education will include the economic and social aspects of distributed “generation” of energy and water from sunlight and rainfall.
Thu, 20 February 2020
ARTICLE | doi:10.20944/preprints202002.0295.v1
Subject: Engineering, Electrical & Electronic Engineering Keywords: cyber-power network; distribution system reliability; FMEA; reliability assessment; risk priority number (RPN); Smart Grid
Online: 20 February 2020 (08:33:27 CET)
Reliability assessment in traditional power distribution systems has played a key role in power system planning, design, and operation. Recently, new information and communication technologies have been introduced in power systems automation and asset management, making the distribution network even more complex. In order to achieve efficient energy management, the distribution grid has to adopt a new configuration and operational conditions that are changing the paradigm of the actual electrical system. Therefore, the emergence of the cyber-physical systems concept to face future energetic needs requires alternative approaches for evaluating the reliability of modern distribution systems, especially in the smart grids environment. In this paper, a reliability approach that makes use of failure modes of power and cyber network main components is proposed to evaluate risk analysis in smart electrical distribution systems. We introduce the application of Failure Modes and Effects Analysis (FMEA) method in future smart grid systems in order to establish the impact of different failure modes on their performance. A smart grid test system is defined and failure modes and their effects for both power and the cyber components are presented. Preventive maintenance tasks are proposed and systematized to minimize the impact of high-risk failures and increase reliability.
ARTICLE | doi:10.20944/preprints202002.0294.v1
Subject: Engineering, Electrical & Electronic Engineering Keywords: bitmap indexing; processing in memory; memory wall; Big Data; Internet Of Things
Online: 20 February 2020 (08:24:48 CET)
To live in the information society means to be surrounded by billions of electronic devices full of sensors that constantly acquire data. This enormous amount of data must be processed and classified. A solution commonly adopted is to send these data to server farms to be remotely elaborated. The drawback is a huge battery drain due to high amount of information that must be exchanged. To compensate this problem data must be processed locally, near the sensor itself. But this solution requires huge computational capabilities. While microprocessors, even mobile ones, nowadays have enough computational power, their performance are severely limited by the Memory Wall problem. Memories are too slow, so microprocessors cannot fetch enough data from them, greatly limiting their performance. A solution is the Processing-In-Memory (PIM) approach. New memories are designed that are able to elaborate data inside them eliminating the Memory Wall problem. In this work we present an example of such system, using as a case of study the Bitmap Indexing algorithm. Such algorithm is used to classify data coming from many sources in parallel. We propose an hardware accelerator designed around the Processing-In-Memory approach, that is capable of implementing this algorithm and that can also be reconfigured to do other tasks or to work as standard memory. The architecture has been synthesized using CMOS technology. The results that we have obtained highlights that, not only it is possible to process and classify huge amount of data locally, but also that it is possible to obtain this result with a very low power consumption.
ARTICLE | doi:10.20944/preprints202002.0292.v1
Subject: Engineering, Electrical & Electronic Engineering Keywords: sliding mode control; position tracking; reference signal generator; telescope mount; motion control; electrical drive
Online: 20 February 2020 (07:54:14 CET)
Precise and fast position tracking is essential for the correct operation of many industrial robots and CNC machine tools. This subject is also important in the control of the mount of the astronomical telescope, especially for the tracking of artificial satellites. As system parameters can change, a control method that is robust to changes in parameters must be used. Such a method is the sliding control, which, however, ensures the robustness only after reaching the sliding surface. Therefore, a new method was proposed in the paper, which eliminates the phase of reaching the sliding surface. The method consists of using a reference trajectory generator and determining the generalized error in relation to this trajectory. The procedure for designing the control system is presented. Next, the proposed method was verified on the laboratory stand. The described control method provides a robust system operation and can be easily implemented in the control system.
ARTICLE | doi:10.20944/preprints202002.0291.v1
Subject: Engineering, Biomedical & Chemical Engineering Keywords: paper based sensor; whole virus; Zika; aptamer
Online: 20 February 2020 (07:24:39 CET)
Paper-based sensors, microfluidic platforms and electronic devices have attracted attention in the past couple of decades because they are flexible, can be recycled easily, environmentally friendly, and inexpensive. Here we report a paper aptamer-based potentiometric sensor to detect the whole Zika virus for the first time with a minimum sensitivity of 2.6 nV/Zika and the minimum detectable signal (MDS) of 1.2x106 Zika. Our paper sensor works very similar to a P-N junction where a junction is formed between two different wet regions with different electrochemical potentials near each other on the paper. These two regions with slightly different ionic contents, ionic species and concentrations, produce a potential difference given by the Nernst equation. Our paper sensor consisted of a 2-3 mm x 10 mm segments of a paper with a conducting silver paint contact patches on its two ends. The paper is soaked in a buffer solution containing aptamers designed to bind to the capsid proteins on Zika. Atomic force microscopy studies were carried out to show both the aptamer and Zika become immobilized in the paper. We then added the Zika (in its own buffer) to the region close to one of the silver-paint contacts. The Zika virus (40 nm diameter with 43 kDa or 7.1x10-20 gm weight), became immobilized in the paper’s pores and bonded with the resident aptamers creating a concentration gradient. The potential measured between the two silver paint contacts reproducibly became more negative as upon adding the Zika. We also showed that an LCD powered by the sensor, can be used to detect the sensor output.
Subject: Engineering, Control & Systems Engineering Keywords: biosensor; optical fiber sensor; two-mode fiber; sensitivity
Online: 20 February 2020 (05:33:03 CET)
Conventional method for monitoring the IgG levels suffered from some apparent problems such as long assay time, multistep processing, and high overall cost. An effective and suitable optical platform for label-free biosensing has been investigated by the implementation of antibody/antigen immunoassays. Thus, the ultrasensitive detection of IgG levels can be achieved by exploiting the dispersion turning point (DTP) existed in the tapered two-mode fibers (TTMFs) due to the sensitivity will reach ±∞ on either side of the DTP. Tracking the resonant wavelength shift it was found that the fabricated TTMF device exhibited limits of detection (LOD) down up to concentrations of 10 fg/mL of IgG in PBS solution. Such immunosensors based on the DTP have great significance on trace detection of IgG due to simple detection scheme, quick response time, and miniaturation.
Wed, 19 February 2020
Subject: Engineering, Industrial & Manufacturing Engineering Keywords: Life Cycle Assessment (LCA); Carbon Footprint (CFP); Tourism
Online: 19 February 2020 (10:28:55 CET)
The importance of the contribution from tourism to climate change was pointed out by the International Tourism Organization (UNWTO). By combining process-based Life Cycle Assessment (LCA) and Input-output analysis, several researches have tried to evaluate the impacts of the tourism industry as well as its products and services. Indeed, the tourism sector has a wide range of industries including travel and tour, transportation, accommodation, food and beverage, amusement, souvenirs etc. However, the existing cases did not show a breakdown of the impact on climate change. In this paper, the carbon footprint (CFP) of the Japanese tourism industry was calculated based on tourist consumption, using the Japanese Input-output table and the Japanese tourism industry. It was shown that the total emissions were approximately 136 million t-CO2 per year. The contribution ratio of each stage is as follows: Transport 56.3%, Souvenirs 23.2%, Petrol (direct emissions) 16.9%, Accommodation 9.8%, Food and Beverage 7.5%, Activities 3.0%. Then, in the breakdown, the impact is high in the following order Air transport 24.7%, Petrol (direct emissions) 16.9%,Accommodation 9.8%, Food and Beverage 7.5%, Petrol 6.1%, Textile products 5.3%, Food items 4.9%, Confectionery 4.8%, Rail transport 3.9%, Cosmetics 1.9%, Footwear 1.8%, etc. In addition to transportation, this research also highlighted especially the contribution from souvenirs, accommodation, food and beverages.
Tue, 18 February 2020
ARTICLE | doi:10.20944/preprints202002.0262.v1
Subject: Engineering, Other Keywords: CCM; CINR; Cost per Gbps in orbit; Multibeam Satellite Communications; System Optimization; VCM; VHTS
Online: 18 February 2020 (08:53:14 CET)
The concept of geostationary VHTS (Very High Throughput Satellites) is based on multibeam coverage with intensive frequency and polarization reuse in addition to the use of larger bandwidths in the feeder links, in order to provide high capacity satellite links at a reduced cost per Gbps in orbit. The dimensioning and design of satellite networks based on VHTS imposes the analysis of multiple trade-offs to achieve an optimal solution in terms of cost, capacity and figure of merit of the user terminal. In this paper, we propose a new method for sizing VHTS satellite networks based on an analytical expression of the forward link CINR (Carrier-to-Interference-plus-Noise Ratio) that is used to evaluate the trade-off of different combinations of system parameters. The proposed method considers both technical and commercial requirements as inputs including the constraints to achieve the optimum solution in terms of the user G/T, the number of beams and the system cost. The cost model includes both satellite and ground segments. Exemplary results are presented with feeder links using Q/V bands, DVB-S2X and transmission methods based on CCM and VCM (Constant and Variable Coding and Modulation, respectively) in two scenarios with different service areas.
Mon, 17 February 2020
ARTICLE | doi:10.20944/preprints202002.0237.v1
Subject: Engineering, Marine Engineering Keywords: Colombia; Colombian Caribbean; marine climate; Mallorquín Lagoon; Puerto Colombia; Wave Watch III; wave; wind
Online: 17 February 2020 (03:32:48 CET)
This work presents an application called APPMAR 1.0 based on Python ® environment, built to perform the downloading, treatment and analysis of meteorological and marine information. This application is composed of two main modules: the first module allows the downloading of information from the database (NOAA - WW3); the second module uses the principles of statistical mathematics for the treatment of waves and wind. The importance of this simple application is based on the free and agile access to meteorological and marine information for a coastal project. The determination of representative conditions of sea states ultimately will govern the process of design of coastal and oceanic infrastructure. The analysis of historical time series of local waves and winds allows the evaluation of average regimes or operational design, the ultimate limit states or extreme design, and the storms or design by persistence. In spite that the former analysis is a common task for coastal engineers, the codes generated are seldom shared for public use. In summary, for operational purposes is useful to have a freeware that can assist in the data processing for decision making and forcing of the mathematical models that are part of the common practice of coastal, oceanic and offshore engineering. This application has been tested in the Caribbean area of Colombia where meteorological and marine information are scarce.
ARTICLE | doi:10.20944/preprints202002.0232.v1
Subject: Engineering, Biomedical & Chemical Engineering Keywords: electromagnetic properties of viruses; terahertz sensors; label-free detection of viruses; nanotechnologies
Online: 17 February 2020 (01:56:06 CET)
Our main objective in this work was to examine the possibility of non-intrusive, label-free, detection of whole Zika viruses using terahertz signals with or without a targeting/binding oligonucleotide (aptamers). We report for the first time the use of terahertz electromagnetic waves (0.75 THz – 1.1 THz) to detect Zika viruses. The Zika/aptamer complexes showed a reproducible terahertz reflection coefficient minimum at 1.064 THz while the Zika virus’s reflection minimum was at 1.073 THz. Of different substrates we examined, the polyester petri dish provided a very low loss and excellent terahertz transmission. To increase the interaction between the terahertz signal and the sample we also used polyester microbeads coated with aptamers. We then measured the terahertz reflection from the microbeads as a function of Zika concentration. The resulting terahertz Zika sensor had sensitivity of 63 Hz/Zika and minimum detectable signal of ~ 16x103 Zika. Other substrates such as Graphene on polyethylene terephthalate (PET), 50 nm-thick gold film on polycarbonate, thin (30 um-thick) glass slide and Teflon were also examined. Graphene substrate enabled direct detection of the Zika without any aptamers.
Subject: Engineering, Control & Systems Engineering Keywords: IPMC (Ionic Polymer Metal Composites); Reduced Order Controller; LabVIEW; Back-Relaxation
Online: 17 February 2020 (01:07:56 CET)
In this work, NPP (Nernst-Planck-Poisson) model is chosen to be the base model for the IPMC back-relaxation behavior modeling. Based on experimental data, a new model was created. Then, a reduced order control system is designed and verified using MATLAB & Simulink tools. The simulation shows that the developed model can be used to model the system without loss of accuracy. Next, using the I/O capabilities of the NI-ELVIS II development board and its hardware compatibility with NI LabVIEW 2018, a controller was designed and built, and then verified under different excitation input signals. The controller showed excellent tracking performance with tracking error as small as 5%. The controller can be
Sun, 16 February 2020
ARTICLE | doi:10.20944/preprints202002.0225.v1
Subject: Engineering, Industrial & Manufacturing Engineering Keywords: selective laser melting; 316L stainless steel; multi-objective optimization; relative density; surface roughness
Online: 16 February 2020 (15:52:05 CET)
Although the concept of additive manufacturing has been proposed for several decades, momentum of selective laser melting (SLM) is finally starting to build. In SLM, density and surface roughness, as the important quality indexes of SLMed parts, are dependent on the processing parameters. However, there are few studies on their collaborative optimization in SLM to obtain high relative density and low surface roughness simultaneously in the previous literature. In this work, the response surface method was adopted to study the influences of different processing parameters (laser power, scanning speed and hatch space) on density and surface roughness of 316L stainless steel parts fabricated by SLM. The statistical relationship model between processing parameters and manufacturing quality is established. A multi-objective collaborative optimization strategy considering both density and surface roughness is proposed. The experimental results show that the main effects of processing parameters on the density and surface roughness are similar. It is noted that the effects of the laser power and scanning speed on the above objective quality show highly significant, while hatch space behaves an insignificant impact. Based on the above optimization, 316L stainless steel parts with excellent surface roughness and relative density can be obtained by SLM with optimized processing parameters.
ARTICLE | doi:10.20944/preprints202002.0210.v1
Subject: Engineering, Civil Engineering Keywords: non-linear static (Pushover) analysis; modal pushover; non-linear time-history analysis; incremental analysis; bridges; assessment of bridges; seismic response of bridges
Online: 16 February 2020 (04:34:37 CET)
A large number of bridges are designed and built without considering seismic actions and, differently from buildings, there are currently no comprehensive guidelines to evaluate existing bridges without performing, as in the well known incremental dynamic analysis (IDA), complex non linear dynamic analyses (RHA). Bridges are structurally very different from building but, at the same time, are sensitive to higher modes as well as many multi-storey buildings that inspired innovative pushover procedures such as the well known modal pushover analysis (MPA). In the present study the incremental modal pushover analysis (IMPA), a pushover based approach already proposed and applied on buildings by the same authors, is revised and proposed for bridges (IMPAβ). IMPAβ accounts for the effects of higher modes in order to accurately estimate the seismic response of bridges; the effect of higher modes is considered by introducing a suitable number of modes to ensure the participation of a predefined total effective modal mass. The efficiency of the proposed method is demonstrated by conducting a study on two bridges, one regular and one irregular, and the IDA analysis is employed as reference solution. Numerical results indicate good accuracy of the proposed method in assessing the seismic response and a very good accuracy if compared to other available pushover procedures available in the literature.
Fri, 14 February 2020
ARTICLE | doi:10.20944/preprints202002.0189.v1
Subject: Engineering, Electrical & Electronic Engineering Keywords: network monitoring; spectrum sharing; Wi-Fi tethering; sensing of misbehavior
Online: 14 February 2020 (04:54:35 CET)
Wi-Fi tethering using a mobile device (e.g., a smartphone or a tablet) as a hotspot for other devices has become a common practice. Despite the potential benefits of Wi-Fi tethering, the open source nature of mobile operating systems (e.g., Google Android) can be abused by a selfish device to manipulate channel-access parameters to gain an unfair advantage in throughput performance. This can cause serious performance problems within a well-planned Wi-Fi network due to an unauthorized selfish or misconfigured tethering device interfering with nearby well-planned access points (APs). In this paper, we demonstrate that the selfish behavior of a tethering node that adjusts the clear channel assessment (CCA) threshold has strong adverse effects in a multi-AP network, while providing the selfish node a high throughput gain. To mitigate this problem, we present a passive online detection scheme that identifies the network condition and detects selfish tethering nodes with high accuracy by exploiting the packet loss information of on-going transmissions. To the best of our knowledge, this is the first research to consider the problem of detecting a selfish tethering node in managed Wi-Fi networks.
Thu, 13 February 2020
ARTICLE | doi:10.20944/preprints202002.0174.v1
Subject: Engineering, Electrical & Electronic Engineering Keywords: IEEE 802.15.4g; Smart Utility Networks; Low-Power; Wireless; Communications; Dependable; Predictable; Reliable; Available; Industrial; Dataset
Online: 13 February 2020 (14:01:05 CET)
In this article we present a deployment of 11 nodes using the three different SUN (Smart Utility Network) modulation schemes, as defined in the IEEE 802.15.4-2015 standard. The nodes were deployed in a 110.044 m2 warehouse for 99 days, and the resulting dataset contains a total of 10.710.868 measurements with RSSI (Received Signal Strength Indicator), CCA (Clear Channel Assessment) and PDR (Packet Delivery Ratio) values. The analyzed results show a high variability in average RSSI (i.e., between -82.1 dBm and -101.7 dBm) and CCA (i.e., between -111.2 dBm and -119.9 dBm) values, which are caused by the effects of multi-path propagation and external interference. Despite being above the sensitivity limit for each modulation, this values result in poor average PDR values (i.e., from 65.9% to 87.4%), indicating that additional schemes are required for low-power wireless communications to meet the dependability requirements of industrial applications. For that purpose, we also introduce the concept of modulation diversity, which can be combined with packet repetition to meet such requirements (i.e., PDR>99%) while minimizing the energy expenditure of nodes and meeting regulatory constraints.
ARTICLE | doi:10.20944/preprints202002.0172.v1
Online: 13 February 2020 (12:54:49 CET)
The quality and shelf-life of NCS (Non-centrifugal sugar) mainly depend on the moisture content present in it. NCS formed by the current practice of open sun drying contains moisture substantially greater than the acceptable level of 3%. This paper presents the work taken up to design a tunnel dryer to attain require moisture content in granular NCS for various load conditions. Initially, an experimental investigation had been carried out on a laboratory scale dryer to achieve required moisture content (< 3%) for various load conditions. This experimental data was used for validating two drying models and found that one of the models is best suitable for designing an industrial-scale dryer. For various load conditions on each tray and dryer exit temperature, nine different cases were arrived at. The number of trucks, trays, drying time and energy requirements were computed using the suitable theoretical model. Tunnel dryer with a length of 18 m, a height of 1.2 m, a width of 1 m, number of trucks of 18 and 24 number of trays on each truck was found to be the suitable dryer to dry 1 tone of NCS based on the minimum energy requirement of 176.49 MJ, and a minimum drying time of 68 minutes.
Wed, 12 February 2020
Subject: Engineering, Civil Engineering Keywords: escherichia coli; e. coli; indicator; fecal coliform bacteria; water; bacteriological analysis; fcb; classification
Online: 12 February 2020 (12:12:00 CET)
Escherichia coli or E. coli is a member of the fecal coliform group and is a more specific indicator of fecal contamination than other fecal coliform species, its presence indicate possibly presence of harmful bacteria which will cause diseases and it also suggests the extent as well as the nature of the contaminants. E. coli bacteria able to survive in water for 4 – 12 weeks and at present, it appears as an indicator to provide the accurate bacterial contamination of fecal matter in drinking water, because of the availability of simple, affordable, fast, sensitive and exact detection techniques. According to the laboratory experiment based techniques, 24 - 48 hours are required for the bacterial concentration to be reported. So, there is a necessity for continuous monitoring. Techniques for detection of many pathogenic bacterial strains are not yet available, sometimes days to weeks are required to get the results. To overcome the difficulties, expensive and time-consuming techniques are required to detect, count and identify the presence of specific bacterial strain. Public health relies on online monitoring of water quality that depends majorly on examination of fecal indicator bacteria, thus protection of health requires fecal pollution indicator so that it is not required to analyze drinking water to overcome the problems associated with waterborne diseases. This paper will brief the classification, sources, survival of E. coli bacteria and its correlation with basic water quality parameters in water sources.```
Tue, 11 February 2020
ARTICLE | doi:10.20944/preprints202002.0149.v1
Subject: Engineering, Civil Engineering Keywords: Water Demand; Water Supply; Performance; Hydraulic Modeling; Water GEMSV8i
Online: 11 February 2020 (14:52:17 CET)
This study was conducted generally by aiming assessment of the hydraulic performance of water distribution systems of Addis Ababa Science and Technology University (AASTU). In line with the main objective, this study addressed, (1) pinpointing problems of existing water supply versus demand deficit (2) evaluating the hydraulic performance of water distribution system using water GEMS and (3) recommended alternative methods for improving water demand scenarios. The University’s water supply distribution network layout was a looped system and the flow of water derived by both gravity and pressurized system. The gravity flow served for the academic and administrative staffs whereas the pressurized system of the network fed the students dormitories, cafeteria’s etc. The study revealed the existence of unmet minimum pressure requirement around the student dormitories which accounts 25.64% below the country’s building code standard during the peak hour consumption. The result of the water demand projection showed an increment of 2.5 liter per capita demand (LPCD) in every five years. Hence, first, the university’s water demand was projected and then hydraulic parameters such as; pressure, head loss and velocity were modeled for both the existing and the improved water supply distribution. The finding of the study was recommended to the university’s water supply project and institutional development offices for its future modification and rehabilitation works.
ARTICLE | doi:10.20944/preprints202002.0144.v1
Subject: Engineering, Mechanical Engineering Keywords: undersea project; measuring the two pipelines; rotating shaft; magnetic coupling; assisted rope winch
Online: 11 February 2020 (11:40:30 CET)
In order to solve the problem of measuring the distance and position between the flanges of two pipelines on the seabed, a measuring device for pulling rope in seawater was designed. Aiming at the sealing problem of the key equipment that is the rotating shaft of the rope winch, this paper used the principle of the magnetic coupling to transfer the driving moment, and adopted the method of converting the dynamic seal into the static seal structure to realize the reliable sealing of the motor. Through the experiment of measuring two pipelines with underwater rope pulling device, it was verified that the measuring accuracy of the device meets the design requirements, and the feasibility of the application of magnetic coupling technology in winch is also verified.
ARTICLE | doi:10.20944/preprints202002.0135.v1
Online: 11 February 2020 (09:08:08 CET)
In this paper a low profile antenna is presented for wideband communication applications. The presented design is consists of an I-shape driven strip and a rectangular ground strip with an open slot in the middle and steeped lower portion. Measured result demonstrates that the achieved operating band of the proposed antenna has the potential to cover Global Star Satellite Phones (1.61-1.63 GHz, uplink), Advanced Wireless Systems (1.71-1.76 GHz, 2.11-2.17 GHz), DCS (1710-1880 MHz), GSM (1800MHz), DCP (1.88-1.90 GHz), DCS-1900/PCS/PHS (1850-1990MHz), WCDMA/IMT-2000 (1920-2170MHz), UMTS (1920-2170 MHz), LTE bands (FDD LTE bands 1-4, 9-10, 15-16, 23-25, 33-37, 39). The designed antenna possessed a very small size of 0.35λ0 × 0.027λ0 at the lowest frequency (S11 ≤ -10dB) and achieved good gain, exhibits stable radiation patterns which make it suitable for handheld communication devices.
Mon, 10 February 2020
ARTICLE | doi:10.20944/preprints201912.0014.v3
Subject: Engineering, Civil Engineering Keywords: Discrete Element Method (DEM); Cell Method (CM); multiscale modeling; periodic composite materials; nonlocality
Online: 10 February 2020 (10:09:46 CET)
This paper presents a new numerical method for multiscale modeling of composite materials. The new numerical model, called DECM, consists in a DEM (Discrete Element Method) approach of the Cell Method (CM) and 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 continuous media, 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 in composite continua.
Sat, 8 February 2020
ARTICLE | doi:10.20944/preprints202002.0101.v1
Subject: Engineering, Other Keywords: accessibility; food service facilities; grocery retailers; city logistics; last-mile delivery
Online: 8 February 2020 (05:48:17 CET)
Access to food systems is essential to sustain urban life. In this paper, we discuss the differences concerning accessibility levels to food systems among potential consumers in Belo Horizonte, Brazil. The goal was to characterize spatial mismatches regarding food opportunities and identify suitable areas for sustainable food mile solutions, such as non-motorized home delivery and purchase trips. For this, we have spatially related: (i) the population concentration; (ii) the income of households; and (iii) accessibility measures considering both the spatial structure of food retailers and the distance between households and stores, considering the food mile. We have then used spatial statistics and spatial analysis methods to determine the spatial pattern of variables and the cumulative opportunity measure for households. There is great spatial differentiation regarding the accessibility levels of food retailers and the results can be considered to support the development of policy and land use regulation that can stimulate non-motorized and collaborative delivery as an effective last-mile solution.