REVIEW | doi:10.20944/preprints202102.0409.v1
Subject: Social Sciences, Education Keywords: Professional development for scientists; tenure-track faculty; tenure; professoriate; professional development practicum; professional development experiential learning; Accomplishing Career Transitions; American Society for Cell Biology; Minorities Affairs Committee
Online: 18 February 2021 (10:43:19 CET)
Experiential learning can facilitate the development of transferrable skills necessary for success in attaining tenure and promotion in academia. In this article, we discuss the benefits of designing and implementing an individualized professional development experience or practicum. By doing this, we describe the experiential learning component of the Accomplishing Career Transitions (ACT) Program of the American Society for Cell Biology. The ACT program aims to assist postdoctoral trainees and junior faculty from backgrounds underrepresented in STEM as they strive to transition into tenure-track positions and ultimately attain tenure at research-intensive or teaching-intensive academic institutions.
ARTICLE | doi:10.20944/preprints202304.1196.v1
Subject: Social Sciences, Urban Studies And Planning Keywords: Insecure Tenure; Land Tenure; Urban Housing; Conurbation, Benin
Online: 29 April 2023 (03:30:31 CEST)
This study focuses on land tenure in an urban environment. Specifically, it intends to elucidate the influence of land tenure security on access to housing in urban communities. The conurbation of Grand Nokoué, which is an agglomeration of five cities in the Republic of Benin, West Africa, captures attention due to its particular features as a developing city. Based on the literature, this study outlined three major factors of insecure land tenure, namely, lack of recognition by authorities, lack of protection from eviction or expulsion, and informal community-based rights. In addition, we examined four characteristics of relevant housing issues, namely, the development of shantytowns, the multiplicity of precarious housing, the loss of housing for the development of public projects, and exposure to house demolition under judicial decision to formulate our hypotheses. The results of a field observation and semi-structured interviews supported the hypotheses and demonstrated that the legal access to land, the protection of the population from anarchic eviction and informal community-based rights may positively influence the development of sustainable urban housing.
ARTICLE | doi:10.20944/preprints202101.0136.v1
Subject: Social Sciences, Area Studies Keywords: Land dispute, customary land tenure, statutory land tenure, tenure security, Ghana, sub-Saharan Africa
Online: 8 January 2021 (10:31:29 CET)
Despite the ongoing land administration reforms being implemented across sub-Saharan Africa (SSA), including Ghana as viable pathway to achieve tenure security and greater efficiency in land administration, the subject of land dispute resolution has received relatively less attention. Whereas customary tenure institutions play a central role in land administration (controlling ~80% of all land in Ghana), they remain at the fringes of the formal land dispute adjudicatory process. Recognizing the pivotal role traditional institutions as development agents and potential vehicles for promoting good land governance, recent discourse on land tenure have geared towards mainstreaming traditional land disputes institutions into the architecture of formal judicial process via alternative dispute resolution pathways. Yet little is known at least empirically as to the operations of traditional dispute resolution institutions in the contemporary context. This study therefore explores the importance of traditional dispute resolution institutions in the management of land-related disputes in southcentral and western Ghana. Drawing on data collated from 380 farming households operating 746 plots. The results show that contrary to the conventional thinking that traditional institutions are anachronistic and not fit for purpose, they remain strong and preferred forum for land dispute resolution (proving resilient and adaptable) given the changing socio-economic and tenurial conditions. Yet these forums have differing implications for different actors within the customary spheres accessing them. The results highlight practical ways for incorporating traditional dispute resolution in the overall land governance setup in Ghana and elsewhere in sub-Saharan Africa. This has implications for redesigning context-specific and appropriate land-use policy interventions that address local land dispute resolution.
ARTICLE | doi:10.20944/preprints202109.0498.v1
Subject: Engineering, Civil Engineering Keywords: Railway; Track bed; Track bed failure; Railway track; Track bed failure remedy
Online: 29 September 2021 (14:23:30 CEST)
The polymer cures as it enters the ballast, forming a three-dimensional geo-composite reinforcing cage. Although there will be some adherence to the ballast in dry conditions, the polymer's primary job is to construct this reinforcing cage. Polymer penetration is controlled by altering the rheology of the polymer. The method is also said to include a built-in safety system, with the track reverting to a ballast state in the event of a polymer or geo-composite failure. Many of the sites were considered unmaintainable before the polymer was put. The design method was utilized to forecast track behaviour before and after treatment, allowing the most appropriate polymer rheology, polymer distribution, and loading levels to be designed in order to achieve optimum performance and confirm that the procedure worked. This method can be utilized to tackle these types of long-standing problems by displaying actual polymer application profiles at a typical important location.
Subject: Biology And Life Sciences, Cell And Developmental Biology Keywords: tenure preparation; biomedical faculty
Online: 18 December 2020 (07:22:48 CET)
At research-intensive universities in the United States, eligible faculty must generally excel in research, teaching and service in order to receive tenure. To meet these high standards, junior faculty should begin planning for a strong tenure case from their first day on the job. Here, we provide practical information, commentary and advice on how biomedical faculty at research-intensive institutions can prepare strategically for a successful tenure review.
ARTICLE | doi:10.20944/preprints202104.0396.v1
Subject: Business, Economics And Management, Accounting And Taxation Keywords: Indigenous; toponomy; land tenure; cartography
Online: 14 April 2021 (17:51:47 CEST)
In recent years, many libraries and archives have started digitizing their collections thus making maps by Indigenous peoples more easily available for scholars to study. While a number of these maps were discussed by G. Malcolm Lewis in the History of Cartography series (volume 2, book 3, Chapter 4: 1984), more have since been found and disseminated. These maps are critical in understanding the historic and current land tenure of Indigenous groups. Further, Indigenous claims to land can be seen in their connections via toponymy. European concepts of territory and political boundaries did not coincide with First Nation/American Indian views resulting in the mistaken view that Natives did not have formal concepts of their territories. Further, Tribes/First Nations with cross-border territory have special jurisdictional problems. This paper will illustrate how many Native residents were very spatially cognizant of their own lands, as well as neighboring nations’ lands, overlaps between groups, hunting territories, populations, and trade networks. Currently, the Sinixt First Nation provides a perfect example of how an Aboriginal people are inputting and using a GIS representation of their territory with proper toponymy and use areas.
ARTICLE | doi:10.20944/preprints201807.0513.v1
Online: 26 July 2018 (13:15:59 CEST)
Team spirit is often considered a peculiar characteristic of sportspersons. While the importance of unity among athletes is evident in team games, its relevance in the training of sportspersons of individual sports, especially track and field athletics, is often not recognized. The purpose of this study is to review how team cohesion impacts athletes of various sports and understand how it could contribute to the overall performance of track and field athletes, who mainly compete individually.
ARTICLE | doi:10.20944/preprints202205.0048.v1
Subject: Social Sciences, Geography, Planning And Development Keywords: Sustainable Development Goals; SDGs; land conflicts; land tenure security; Uganda
Online: 5 May 2022 (16:03:11 CEST)
Land tenure security is important for achieving a number Sustainable Development Goals (SDGs). The purpose of this paper was to investigate variation in land tenure security across three districts located in different geographical regions of Uganda. Using a quantitative cross-sectional survey data collected in early 2019. The findings show that Kanungu district found in South-Western Uganda had significantly higher levels of land tenure security as compared to Nakasongola (Central) and Nwoya (Northern). Research findings have implications on further study and benchmarking land governance systems in Kanungu. Furthermore, they have implications on implementation of government and donor land titling or registration programs in terms of priority areas. They further sheds light on the importance of accounting for geographical context in land tenure studies.
COMMUNICATION | doi:10.20944/preprints202309.1634.v1
Subject: Environmental And Earth Sciences, Atmospheric Science And Meteorology Keywords: tropical cyclone; track; intensity; wind structure
Online: 25 September 2023 (09:32:43 CEST)
Hong Kong was under strike from Super Typhoon Saola (2309), necessitating the issuance of the highest tropical cyclone warning signal. Saola skirted past the south-southwest of Hong Kong, bringing hurricane force winds and significant storm surge. Saola had its closest approach to Hong Kong on 1 September 2023, posing a unique challenge in forecasting and early warning for the commencement date of the new school term, where higher impact to traffic and public safety was anticipated. This paper covers the challenges on the forecasting aspect of the super typhoon. The predicted tropical cyclone track, intensity and wind structure are reviewed. Experience in this case showed that while there was not a perfect numerical weather prediction model in terms of the forecast track, intensity and wind structure of Saola, multi-model approach provided very use-ful and crucial information for operational weather warning services.
Subject: Physical Sciences, Radiation And Radiography Keywords: radiation track chemistry; chemical track structure; oxygen effect; oxygen depletion; ion beam therapy; ROS; superoxide anion
Online: 5 December 2019 (03:32:18 CET)
The radiosensitivity of biological systems is strongly affected by the system oxygenation. On the nanoscopic scale and molecular level, this effect is considered to be strongly related to the indirect damage of radiation. Even though particle track radiolysis has been the object of several studies, still little is known about the nanoscopic impact of target oxygenation on the radical yields. We present here an extension of the chemical module of the Monte Carlo particle track structure code TRAX, taking into account the presence of dissolved molecular oxygen in the target material. The impact of the target oxygenation level on the chemical track evolution and the yields of all the relevant chemical species is studied in water under different irradiation conditions: different linear energy transfer (LET) values, different oxygenation levels, and different particle types. Especially for low LET radiation, a large production of two highly toxic species (HO2• and O2•− ), which are not produced in anoxic conditions, is predicted and quantified in oxygenated solutions. The remarkable correlation between the HO2• and O2•− production yield and the oxygen enhancement ratio observed in biological systems suggests a direct or indirect involvement of HO2• and O2•− in the oxygen sensitization effect. The results are in agreement with available experimental data and previous computational approaches. An analysis of the oxygen depletion rate in different radiation conditions is also reported.
ARTICLE | doi:10.20944/preprints202308.0289.v1
Subject: Engineering, Transportation Science And Technology Keywords: DAS; ballastless track; defects recognition; XGBoost; ResNet
Online: 3 August 2023 (10:47:27 CEST)
Defect recognition in ballastless track structures, based on distributed acoustic sensors (DASs), was researched in order to improve detection efficiency and ensure the safe operation of trains on high-speed railways. A line in southern China was selected, and equipment was installed and debugged to collect the signals of trains and events along it. Track vibration signals were extracted by identifying a train track, denoising, framing and labeling to build a defect dataset. Time–frequency-domain statistical features, wavelet packet energy spectra and the MFCCs of vibration signals were extracted to form a multi-dimensional vector. An XGBoost model was trained and its accuracy reached 89.34%. A time-domain residual network (ResNet) that would expand the receptive field and test the accuracies obtained from convolution kernels of different sizes was proposed, and its accuracy reached 94.82%. In conclusion, both methods showed good performance with the built dataset. Additionally, the ResNet delivered more effective detection of DAS signals compared to conventional feature engineering methods.
ARTICLE | doi:10.20944/preprints202307.1992.v1
Subject: Biology And Life Sciences, Biophysics Keywords: Track Cycling; Coaching; Sports Performance; Performance Modelling
Online: 31 July 2023 (02:43:50 CEST)
There is a paucity of data on the progression of track cycling sprinters, and the evolution of training and performance over a training cycle. Following prior research showing relationships between sprint cycling power and endurance cycling power, we compared these relations over a 3-month period. Our hypothesis is large improvements in power would come from training either for sprint power or sprint capacity, and this would be reflected in the data. A total of publicly available 25 datasets. These data were plotted against the line of best fit for 30-s and 2-min power to assess if training towards the line led to better 30-s power. We observe the best performances came from riders who start below the 30-s vs 2-min power line of best fit, with greater capacity and ability to ride fast over a sprint series, and progressing towards focusing on specific power in the final block leading into a competition. These results support the hypothesis of combined capacity and power training based on rider-specific relationship to the line of best fit between these measures versus a strictly maximal power training focus.
ARTICLE | doi:10.20944/preprints202007.0637.v1
Subject: Engineering, Control And Systems Engineering Keywords: Pendulum; H infinity optimal loop shaping; Track
Online: 26 July 2020 (15:34:57 CEST)
In this paper, a horizontally moving suspended mass pendulum base is designed and controlled using robust control theory. H infinity optimal loop shaping with first and second order desired loop shaping function controllers are used to improve the performance of the system using Matlab/Simulink Toolbox. Comparison of the H infinity optimal loop shaping with first and second order desired loop shaping function controllers for the proposed system have been done to track the desired angular position of the pendulum using step and sine wave input signals and a promising result has been obtained succesfully.
ARTICLE | doi:10.20944/preprints202307.0966.v1
Subject: Engineering, Civil Engineering Keywords: transition zones; railway bridges; monitoring and in-situ expertise; railway track stiffness; geometric position of the track; height deformation
Online: 14 July 2023 (05:46:21 CEST)
The subject of the research is the investigation of the behavior of railway tracks in locations with a significant change in the stiffness of the track. These locations can be designed from various structural elements and their materials, and this mainly results in a height change of the track level during its operation. These transition zones are monitored and expertly examined in order to detect undesirable deformations of the geometrical position of the track caused by the trains running. The transition zones are at the points where the fixed track transitions to the classic track bed, in our case it is their combination with bridge structures, especially at their supports. In Slovakia, under the conditions of the Railways of the Slovak Republic, the issue is topical within the framework of the modernization of trans-European railway corridors. The results of experimental measurements and their analysis will provide relevant data for subsequent research solutions for their new numerical modeling, which will ensure a smooth passage through these points of change without height fluctuations, vibrations, and shocks from the wheels of train sets.
ARTICLE | doi:10.20944/preprints201711.0171.v1
Subject: Environmental And Earth Sciences, Environmental Science Keywords: coal tailing; cement; pozzolan; sleepers; slab track; railway
Online: 27 November 2017 (07:31:37 CET)
One source of kaolinite-rich wastes is from mine tailings and the generation of enormous volumes of mine tailings waste is standard practice in this industry. These volumes of waste are, at present, dumped, provoking significant environmental impact and transforming the environment. The impact of storing coal waste requires the study of eco-innovative solutions for the assessment of waste types. The present investigation has the objective of expanding the knowledge on the behavior of new siliceous-aluminum minerals with pozzolanic activity, of added value in the manufacture of similar cements. Four samples were characterized to determine their chemical, morphological and mineralogical composition. The samples were subjected to different thermal activation conditions for the transformation of an inert waste into a material with cementitious properties. XRD analysis have confirmed the total transformation of kaolinite into metakaolinite. The results have shown that after the activation process, the coal refuse presented good pozzolanic activity, meaning that it may be used as a pozzolanic addition in industrial cements, thereby removing high levels of contaminated waste from the environment. In subsequent investigations, research work will continue with the replication of cements with this pozzolanic addition for use in the manufacture of sleepers and slab track railway system.
ARTICLE | doi:10.20944/preprints202107.0282.v1
Subject: Physical Sciences, Radiation And Radiography Keywords: PADC; poly(allyl diglycol carbonate); latent track; track core radius; G value; layered structure; REFIT; NISE; detection threshold; chemical criterion
Online: 13 July 2021 (09:34:32 CEST)
Modified structure along latent tracks and track formation process have been investigated in poly(allyl diglycol carbonate), PADC, which is well recognized as a sensitive etched track detector. This knowledge is essential to develop novel detectors with improved track registration property. The track structures of protons and heavy ions (He, C, Ne, Ar, Fe, Kr and Xe) have been examined by means of FT-IR spectrometry, covering the stopping power region between 1.2 to 12,000 eV/nm. Through a set of experiments on low-LET radiations – such as gamma ray -, multi-step damage process by electron hits was confirmed in the radiation-sensitive parts of the PADC repeat-unit. From this result, we unveiled for the first-time the layered structure in tracks, in relation with the number of secondary electrons. We also proved that etch pit was formed when at least two repeat-units were destroyed along the track radial direction. To evaluate the number of secondary electrons around tracks, a series of numerical simulations were performed with Geant4-DNA. Therefore, we are proposing new physical criterions to describe the detection thresholds. Futhermore, we propose a present issue of the definition of detection threshold for semi-relativistic C ions. And as a possible chemical criterion, formation density of hydroxyl group is suggested to express the response of PADC.
REVIEW | doi:10.20944/preprints202311.0334.v1
Subject: Engineering, Civil Engineering Keywords: railway; track; sustainability; materials; maintenance; monitoring; circular economy; LCA
Online: 7 November 2023 (02:49:46 CET)
Rail, as the cleanest and greenest high-volume transport, has a central role in the decarbonizing, and it is expected to become the backbone of future mobility in the world. It is worthy to highlight that rail generates the lowest CO2 emissions and energy consumption in operation with respect to the other transportation modes but during construction and maintenance phases CO2 emission, energy consumption and other environmental impacts are significant and need to be carefully assessed and properly mitigated. This paper, based on an extensive literature review, provides a comprehensive framework of trends and challenge in railway sustainability. Attention is focused on track and related materials, maintenance strategies, and methods of assessment of the sustainability. Results show that improvement of materials and practices used in construction and appropriate strategies in maintenance, supported by effective monitoring of the state of the track, can reduce the negative effects on the environment and society and contributes to make this transportation mode greener. Proper methods for the assessment of the sustainability, (LCA, Circularity Index) help to quantify the potential of environmental enhancement of different solutions and constitute effective and indispensable tools in the decision-making process.
ARTICLE | doi:10.20944/preprints202309.0483.v1
Subject: Engineering, Transportation Science And Technology Keywords: locomotive; railway track; wheelset; dynamic characteristics; dynamic coefficient; analysis.
Online: 7 September 2023 (04:24:46 CEST)
In the interaction of the rolling stock and the upper structure of the railway track, intense dynamic loads occur. They have a destructive effect both on the parts of the rolling stock and on the elements of the superstructure of the track. In order to develop a durable, rational and reliably functioning design of cars and locomotives with good dynamic properties and good indicators of the impact of rolling stock on the railway track, along with theoretical computational studies, experimental studies are also required, which are usually the final stage in the design and implementation of rolling stock or modernization of existing ones. Locomotives and wagons in order to improve their strength and dynamic performance. The article presents the results of field tests to determine the dynamic performance of the type CKD6e diesel locomotive. The description of the preparation of the CKD6e shunting locomotive for testing is given. An analysis of the dynamic performance of a diesel locomotive during the passage of turnouts, on a straight section of the track and in a curve with a radius of 400 m, was carried out. The studies performed showed that the minimum value of the stability factor against wheel derailment on a straight section of the track is significantly higher than the standard value. The experimentally obtained ratio of frame forces to the static load from the wheelset on the rails, the coefficients of vertical dynamics of the first and second stages of suspension and the coefficient of stability against derailment of the wheel from the rail, registered on the track section in a curve with a radius of 400 m) meet the current requirements. A calculation scheme and equations of vertical oscillations are proposed, an analysis is carried out according to the graphs of movements of bogies and a locomotive body when moving along irregularities of different lengths at different speeds.
ARTICLE | doi:10.20944/preprints202101.0387.v1
Subject: Social Sciences, Education Keywords: Scholarship evaluation; Tenure and promotion; Teaching and mentoring; Researcher evaluation; Academic career; Open science
Online: 19 January 2021 (16:37:50 CET)
In most world’s countries, scholarship evaluation for tenure and promotion continues to rely on conventional criteria of publications in journals of high impact factor and grant funding. Continuing to hire and promote scholars for their achievements in research and in securing research funds exposes universities at risk because students, directly and indirectly through government funds, are the main source of revenues for academic institutions, whereas talented young researchers are those who actually carry out most of the published research. Purposeful scholarship evaluation needs to include all three areas of scholarly activity: research, teaching and mentoring, and service to society. Young scholars seeking tenure and promotion benefit from the practice of open science because it provides better and more impactful results with respect to each of the three areas of scholarship.
ARTICLE | doi:10.20944/preprints201907.0302.v1
Subject: Arts And Humanities, Architecture Keywords: land tenure in Mexico; ejido system; land expropriation; gated-communities; San Andrés Cholula; Ocoyucan
Online: 26 July 2019 (16:40:05 CEST)
The ejido system in Mexico based on communal land was transformed for private ownership due to neoliberal trends during 1990. This research describes the evolution of Mexican land policies that changed the ejido system into private development to answer why land tenure change is shaping urban growth. To demonstrate this, municipalities of San Andrés Cholula and Ocoyucan were selected as a case study. Within this context, we evaluated how much ejido land is being urbanized due to real estate market forces and what type of urbanization model is created. These two areas represent different development scales: S.A. Cholula where its ejidos were expropriated as part of a regional urban development plan; and Ocoyucan where its ejidos and rural land were reached by private developers without local planning. To analyze both municipalities, historical satellite images from Google Earth were used with GRASS GIS 7.4 and corrected with QGIS 2.18. We found that privatization of ejidos fragmented and segregated the rural world for the construction of massive gated-communities. Therefore, a disturbing land tenure change occurred during the last 30 years, hence this research questions the role of local authorities in permitting land use change without regulations or local planning. The resulting urbanization model is a private sector development that isolates rural communities in their own territories, for which we provide recommendations.
ARTICLE | doi:10.20944/preprints202310.1621.v1
Subject: Computer Science And Mathematics, Computer Vision And Graphics Keywords: ballastless track; image shadow removal; generative adversarial network; computer vision
Online: 25 October 2023 (09:19:13 CEST)
Track fasteners play a pivotal role in infrastructure inspection for high-speed rail. Yet, images taken by drones often capture shadows cast by electrical towers flanking the high-speed rail tracks. These shadows can hinder the visibility of the track fasteners, thereby impacting detection efficiency and accuracy considerably. The present paper introduces an end-to-end shadow removal algorithm, rooted in generative adversarial network training. The comprehensive network framework is segmented into three sub-networks: pseudo-mask generation, shadow removal, and result refinement. We have integrated a Fourier convolutional residual module to bolster the feature extraction capability of the generator network. This integration ensures the network retains a global receptive field, even in its more superficial layers. By employing an overall weighted loss function, we enhance the quality of the images produced without shadows. Further, a perceptual loss function has been incorporated to retain the structural information of objects, setting the stage for subsequent defect detection. Our results highlight that Pse-ShadowNet adeptly eradicates fastener shadows while maintaining vital visual features, including object position, structure, texture, edges, and other key visual elements. Consequently, the reconstructed images are detailed and showcase superior image quality.
ARTICLE | doi:10.20944/preprints202307.1436.v1
Subject: Computer Science And Mathematics, Signal Processing Keywords: multi target tracking; false track discrimination; radar; probability of detection
Online: 21 July 2023 (02:34:08 CEST)
: The radar multi target tracking (MTT) technique requires prior knowledge of a number of parameters about the sensor, the target and backgrounds. The Integrated Track Splitting (ITS) is a fully automatic track-while-scan (TWS) target tracking algorithm capable of extracting and tracking a target in a dense clutter environment using quality false track discrimination (FTD) methodology. The computational complexity in ITS algorithm is limited, compared to other algorithms they use statistical methods to discriminate between false and true tracks, such as multiple hypothesis tracking (MHT), mainly due to the FTD performed. The paper provides an analysis of tracking parameters that allows determining the limit of the possibility of successful target tracking. Extensive experiments have confirmed that the recursive determination of the probability of the existence of a track during tracking can confirm a true track and reject a false track. The clutter density, number of random occurred targets, targets load during the maneuver and the target detection probability were varied. The results of experiments, carried out via Monte Carlo simulations, shown over representative confirmed true tracks (CTT) diagrams, root mean square error position and normalized tracking efficiency parametric diagrams allow the user to select optimal multi-target tracking parameters for different scenarios and clutter densities.
ARTICLE | doi:10.20944/preprints202107.0035.v1
Subject: Engineering, Automotive Engineering Keywords: centrifugal pump; impeller; erosion; particle track; particle concentration; flow rate
Online: 1 July 2021 (15:09:10 CEST)
Double suction centrifugal pump installed along the Yellow River faces the serious sediment erosion due to the high sediment content which cause the poor operation efficiency of pump unit. The particle motion characteristics and erosion characteristics in the pump under different flow rates and different particle concentrations were numerically simulated based on the particle track model of solid-liquid two-phase flow. The results show that the flow rate has a significant effect on the particle tracks and the erosion caused by the particles in the impeller. The total erosion rate is positively correlated with the flow rate, and increases with the increase of flow rate. The vortex and secondary flow in the impeller have obvious influence on the particle trajectory, which increases the particle concentration at the trailing edge of the pressure surface and intensifies the impact erosion in this area. The particles carried by the vortex intensifies the local erosion. The particle concentration mainly affects the erosion rate, but has little effect on the erosion position. The in-fluence of flow rate on the pump erosion is greater than that of the particle properties. These results provide a reference for optimization of the design of anti-erosion blades of the double-suction pump and regulation-operation of pumping station.
ARTICLE | doi:10.20944/preprints202308.0634.v1
Subject: Engineering, Architecture, Building And Construction Keywords: Train-induced vibration; Over-track buildings; Sound comfort; Rail transit development
Online: 8 August 2023 (08:36:08 CEST)
Transit-oriented development (TOD), such as metro depot and over-track building complexes, has expanded rapidly in China. Over-track building construction has the advantage of comprehensive utilization of land resources, ease of commuting to work, and provide funds for subway construction. However, there still has a pending problem, disturbance of railway vibration, for TOD. Excessive noise and vibration seriously affect people’s life. To address this challenge, field measurements are used to obtain the vibration source characteristics and vibration propagation of the ground and the superstructure in this study. And the typical metro depot with over-track building in Wuhan was selected. The effects of vibration on the surrounding ground and adjacent buildings caused by the operation of trains have been measured, and the propagation law of train-induced ground vibration acceleration in the time and frequency domains has been analyzed. The distribution and propagation laws of vibration noise, structural noise and secondary structure noise in sensitive areas such as the throat area, depot area, test section and access section of the over-track buildings and their impact laws on the over-track buildings are obtained. And the effectiveness of the vibration and noise reduction methods used were evaluated. Results show that within 43 m from the train running track, the train running induced vertical vibration acceleration level in the high-rise building peak size of 58.8 dB, the average value of 55.62 dB; vibration frequency components are mainly 40-60 Hz. The findings might provide useful insight for designing vibration mitigation systems in new metro depots with over-track buildings.
REVIEW | doi:10.20944/preprints202202.0313.v3
Subject: Medicine And Pharmacology, Pharmacology And Toxicology Keywords: seawater; seawater preparation; Aqua Maris; nasal irrigation; upper respiratory track; otorhinolaryngology
Online: 21 March 2022 (09:16:41 CET)
The history of saline nasal irrigation (SNI) is indeed a long one, beginning from the ancient Ayurvedic practices and starting to gain a foothold in the west at the beginning of 20th century. Today, there is a growing number of papers covering effects of SNI from in vitro studies to randomized clinical trials and literature overviews. Based on the recommendations of most of the European and American professional associations, seawater, alone or in combination with other preparations, has its place in treatment of numerous conditions of the upper respiratory tract (URT), primarily in chronic (rhino)sinusitis, allergic rhinitis, acute URT infections and postoperative recovery. Additionally, taking into account its multiple mechanisms of action and mounting evidence from recent studies, locally applied seawater preparations may have an important role in prevention of viral and bacterial infections of the URT. Therefore, in this review we discuss results published in the past years focused on the seawater preparations and their use in clinical and everyday conditions, since such products are superior to saline, have an excellent safety profile and are recommended by most professional associations in the field of otorhinolaryngology.
ARTICLE | doi:10.20944/preprints202308.0168.v1
Subject: Engineering, Transportation Science And Technology Keywords: urban railway track; DC power system; stray current mitigation; corrosion; stray current
Online: 2 August 2023 (07:50:15 CEST)
Stray currents can cause very rapid degradation and material loss at the points where the current leaves the metal and enters the electrolyte. Nowadays, many resources are invested in the protection of jeopardized structures, such as buried pipelines, from stray current corrosion. This paper describes the measures that need to be considered in the design and construction of track structures to ensure high rail-to-ground resistance and consequently reduce stray currents. The main conclusions from existing guidelines and standards for reducing and controlling stray currents that are applied by various track operators are presented in the paper. Rail-to-ground resistance in different types of tracks structures and rail fastening systems is analysed and optimal type of the track and type of the fastening system is defined. The grounding schemes used on the tracks and their influence on stray current values are described, as well as the influence of traction power substation and rail cross bonding on stray current. Since it is not necessary to apply all the measures described to the same track structure, the paper gives recommendations on which measures to apply when building tracks with continuously fastened rails and which to apply when building tracks with discretely supported and fastened rails.
ARTICLE | doi:10.20944/preprints202306.1666.v1
Subject: Engineering, Architecture, Building And Construction Keywords: Railway bridge dynamics; track-bridge interaction; vehicle-bridge interaction; coupling beam modeling
Online: 23 June 2023 (11:33:15 CEST)
In the computational prediction of bridge vibrations due to high-speed train traffic, the most accurate results can be obtained by considering the interaction dynamics between the train, the superstructure, and the supporting structure. To achieve this, a detailed understanding of the coupling properties of all elements is crucial as they significantly influence the calculated vibrations. The studies in this article investigate the influence of different levels of modeling complexity on the computational acceleration results of single-span girder bridges with a ballasted superstructure. A numerical study on an extensive parameter field of single-span girder bridges is conducted to investigate the influence of modeling the bridge structures as coupling beams, i.e., by considering them as two vertically coupled beams representing the track (rails and sleepers) and the supporting structure. The connection between both beams reflects the stiffness and damping properties of the ballasted superstructure and can reproduce its load-distribution capacity. The excitation is applied as either a moving load or a multi-body model of the train, an Austrian Railjet, to evaluate interdependencies of interaction effects between the vehicle and track, and between track and bridge structure. The reference model is a simply-supported Bernoulli-Euler beam excited by moving axle loads. The comparison of acceleration results allows for identifying critical combinations of structural and train parameters for which the implementation of interaction dynamics has a particularly significant impact on the calculated vibrations and quantifying that impact. These findings provide the possibility of formulating structure-dependent recommendations concerning the targeted application of more complex modeling of the structure (coupling beam model) on the one hand and train (multi-body model) on the other.
ARTICLE | doi:10.20944/preprints201810.0260.v1
Subject: Engineering, Civil Engineering Keywords: tension force; interface damage; CRTSII slab ballastless track; concrete crack; pre-stress
Online: 12 October 2018 (06:34:43 CEST)
There is a confusion in the original design concept for the tensioning of longitudinally connected reinforcement of CRTSII slab ballastless track. In order to clarify the effect of tension value of longitudinal reinforcement on mechanical characteristics of ballastless track, a three dimensional finite element model considering the nonlinear interaction between the track slab and CA mortar of CRTSII slab ballastless track was established. The mechanical characteristics of the track structure under longitudinal tension load and temperature gradient load of the longitudinal joint were calculated. A method of applying pre-stress to post-pouring concrete was proposed according to the concept of pre-stress loss of pretensioning pre-stressed concrete, reasonable tensile force value was proposed after the crack width and the reinforcement stress of the ballastless track in the operation stage were checked and calculated according to the concrete design principle. When the tension force is greater than 300 kN, it’s harmful to the bonding between the slab and mortar layer, which is prone to interlayer damage. In order to adding pre-stress to concrete of wide joints to ensure the longitudinal stability of ballastless track and the reinforcement stress and crack width to meet the design requirements. It is suggested that the tension force value should be 230 kN, and the temperature difference between reinforcement and concrete should be 30 °C before the initial curdle of wide joint concrete.
ARTICLE | doi:10.20944/preprints202307.1758.v1
Subject: Engineering, Civil Engineering Keywords: Cantilever the construction; Rhombus hanging basket; Walking track; Finite element simulation; Mechanical characteristics
Online: 26 July 2023 (10:34:26 CEST)
For enhancing the efficiency of cantilever casting the construction in the bridge, a novel rhombus traveling track of hanging basket was developed and optimized. The civil software titled Midas was applied to analyse the mechanical properties of the hanging basket with full load and control load. The strength and distortion of the walking mechanism were within the specified range when the maximum beam unit internal force of 149.69Mpa, which was less than the allowable stress of steel 175Mpa, and the anti-overturning safety factor of the hanging basket was 2.5 to meet the requirements. Through the comparative analysis of the key components and the finite element calculation, it was found that there was about 30% redundancy in the structure performance. Therefore, further optimization of each structure was carried out, and the front elevation of the main truss of 20° was achieved. It obtained the best performance in all aspects.
ARTICLE | doi:10.20944/preprints202309.0750.v1
Subject: Engineering, Civil Engineering Keywords: integral transforms; contour integration; ballasted railway track; critical velocity; instability of moving inertial objects
Online: 13 September 2023 (02:25:59 CEST)
Ballasted railway tracks can be modelled using reduced/simplified models composed of several layers of discrete components. This paper deals with the two-layer model, which is very popular due to its computational efficiency. In order to provide some recommendations for track design, it is necessary to identify which set of parameters leads to some irregular/unexpected behavior. Such irregularity is investigated at three levels, such as: (i) critical velocity of moving constant force; (ii) instability of a single moving mass; (iii) instability of two moving masses. All results are presented in dimensionless form to cover a wide range of real parameters. Irregular cases are identified by sets of parameters leading to them and then general conclusions are drawn. Regarding the method, all results are obtained analytically or semianalytically, where “semi” refers to solving the roots of a given polynomial by predefined numerical procedures in symbolic software. No numerical integration is involved in all results presented. This means that the results are highly accurate and refer to exact values, so any kind of parametric or sensitivity analyses is readily possible.
ARTICLE | doi:10.20944/preprints202308.2091.v1
Subject: Engineering, Automotive Engineering Keywords: wheel-track composite unmanned vehicle; complex environment; differential steering mechanism; steering radius; neural network
Online: 30 August 2023 (13:17:56 CEST)
In order to solve the problems of complicated steering control of unmanned vehicles in the field and difficult steering on complex roads, we designed a wheel-track composite vehicle equipped with a novel power differential steering mechanism with dual driving, which drove the steering of the vehicle through the differential rotation of the rear two wheels. The unmanned vehicle was simple to control, small in size, and able to work under the conditions of complex roads, such as hills, mountains, and muddy land. Firstly, a steering mechanism with both differential speed and force was designed to prevent the vehicle from skidding into muddy land and stopping motionless. Secondly, the kinematics model and dynamics model of the two drive shafts and the two output shafts (wheel shafts) were established. Thirdly, according to the relationship between the rotational speed of the two output shafts and the steering radius of the vehicle, the kinematic model of the rotational speed of the two input shafts and the steering radius of the wheel-track composite vehicle was obtained. Finally, according to the test data, the mathematical model of rotational speeds of the two input shafts and the actual steering radius of the vehicle was obtained by neural network fitting, and the maximum relative error between the model results and the actual steering radius value was 3.53%. The combination of power differential steering mechanism and wheel-track composite unmanned vehicle increased the adhesion with the ground and could better adapt to the complex road environment. In conclusion, the unmanned vehicle had the advantages of continuous radius steering, deceleration and torsion increase, differential lock, etc. It was suitable for all-terrain military and civilian vehicles and various special equipment mobile platforms of the walking device, and the research results could provide theoretical references for the steering control and structural optimization of the wheel-track composite vehicle under the environment of complex road surface.
ARTICLE | doi:10.20944/preprints202107.0066.v1
Subject: Engineering, Automotive Engineering Keywords: ballasted track; unsupported sleepers; sleeper-ballast dynamic impact; dynamic simulation; analytic solution; discrete element modelling
Online: 2 July 2021 (15:39:20 CEST)
Unsupported sleepers or void zones in ballasted tracks are one of the most recent and frequent track failures. The void failures have the property of intensive development that, without timely maintenance measures, can cause the appearance of cost-expensive local instabilities like subgrade damages. The reason of the intensive void development lies in the mechanics of the sleeper and ballast bed interaction. The particularity of the interaction is a dynamic impact that occur due to void closure. Additionally, void zones cause inhomogeneous ballast pressure distribution between the void zone and fully supported neighbour zones. The present paper is devoted studying the mechanism of the sleeper-ballast dynamic impact in the void zone. The results of experimental in-situ measurements of rail deflections showed the significant impact accelerations in the zone even for light-weight slow vehicles. A simple 3-beam numerical model of track and rolling stock interaction has shown the similar to the experimental measurements dynamic interaction. Moreover, the model shows that the sleeper accelerations are more than 3 times higher than the corresponding wheel accelerations and the impact point appear before the wheel enters the impact point. The analysis of ballast loadings shows the specific impact behaviour in combination with the quasistatic part that is different for void and neighbour zones, which are characterised with high ballast pre-stressed conditions. The analysis of void sizes influence demonstrate that the impact loadings, wheel and sleeper maximal accelerations appear at certain void depth after which the values decrease. The ballast quasistatic loading analysis indicates more than twice increase of the ballast loading in neighbour zones for long voids and almost full quasistatic unloading for short length voids. However, the used imitation model cannot explain the nature of the dynamic impact. The mechanism of the void impact is clearly explained by the analytic solution using a simple clamped beam. A simplified analytical expression of the void impact velocity shows that it is linearly related to the wheel speed and loading. The comparison to the numerically simulated impact velocities shows a good agreement and the existence of the void depth with the maximal impact. An estimation of the long-term influences for the cases of normal sleeper loading, high ballast pre-stress and quasistatic loading in the neighbour zones and high impact inside the void are performed.
ARTICLE | doi:10.20944/preprints201805.0087.v1
Subject: Engineering, Electrical And Electronic Engineering Keywords: target detection; radar systems; K-distributed clutter; heavy-tailed; Swerling target; track-before-detect (TBD)
Online: 4 May 2018 (08:27:25 CEST)
This paper considers the detection of fluctuating target in heavy-tailed clutter through the use of dynamic programming based on track-before-detect (DP-TBD) in radar systems. The clutter is modeled in terms of K-distribution, which can be widely used to describe non-Gaussian clutter received from high-resolution radars and radars working at small grazing angle. Swerling type 1 is considered to describe the target fluctuation between scans. Conventional TBD techniques suffer from significant performance loss in heavy-tailed environments due to the more frequent occurrences of target-like outliers. In this paper, we resort to DP-TBD algorithm based on prior information, which can enhance the detection performance by using the environment and target fluctuating information during the integration process of TBD. Under non-Gaussian background, the expressions of the likelihood ratio merit function for Swerling type 1 target are derived first. However, the closed analytical form of the merit function is difficult to be obtained. In order to reduce the complexity of evaluating the merit function and the computational load, an efficient approximation method as well as a two-stage detection approach is proposed and used in the integration process. Finally, several numerical simulations of the new strategy and the comparisons are presented to verify that the proposed algorithm can improve the detection performance, especially for fluctuating target in heavy-tailed clutter.
ARTICLE | doi:10.20944/preprints202309.1803.v1
Subject: Environmental And Earth Sciences, Environmental Science Keywords: machine learning; remote sensing; timber harvesting; soil erosion susceptibility; extra gradient boost (XGB); UAV; wheel track
Online: 27 September 2023 (06:01:45 CEST)
Unmanned aerial vehicle (UAV) systems are widely used in many forest-related fields owing to their cost-intensive and precise surveying technology. This study classified erosion susceptibility (ES) in a timber harvesting area using machine learning (ML) and statistical approaches. In dataset generation for the training and testing process, the digital surface model (DSM) of difference (DoD) for July–June was utilized as a dependent variable, and six terrain maps of the DSM for June were used as independent variables. The ES threshold was set at 5 cm for the binary classification of ES pixels while processing using ML (e.g., random forest and extra gradient boost [XGB]) and statistical (e.g., logistic regression) algorithms for model development. The overall accuracy (OA), receiver operating characteristics, and area under the curve (AUC) were calculated for model accuracy and validation. Although the AUC of all models did not appear acceptable (AUC > 0.7), the XGB model showed the best performance regarding time duration, OA, and AUC by 2 h, 64%, and 0.63, respectively. Despite the low AUC and accuracy of the XGB model, the wheel tracks and edges of the operation road were determined to be susceptible areas in the ES map of the XGB.
ARTICLE | doi:10.20944/preprints202208.0247.v1
Subject: Biology And Life Sciences, Animal Science, Veterinary Science And Zoology Keywords: animal welfare; pain; farm animals; Pain-Track; Cumulative Pain; pain assessment; welfare foot-print; time; interspecific comparisons
Online: 15 August 2022 (03:57:59 CEST)
We describe a recently developed approach to quantify welfare loss in animals, the Cumulative Pain metric. It combines the two most relevant dimensions of negative affective experiences: intensity and duration. The metric enables estimating the time individuals spend in negative affective states of a physical or psychological nature (operationally referred to simply as ‘pain’) of different intensities as the result of one or more challenges (e.g., diseases, injuries, deprivations). A new notation protocol (the Pain-Track) is used in which the duration of the experience is represented along the horizontal axis and intensity is represented by four categories in the vertical axis. Pain experiences are partitioned into temporal segments, where hypotheses for the experienced duration and intensity are proposed based on existing welfare indicators (e.g., neurophysiological, behavioral, anatomical, evolutionary). This structure forces transparency about assumptions and uncertainties, highlights knowledge gaps, and enables estimates to be continuously adjusted. Because the Cumulative Pain metric is based on parameters with a broadly common biological meaning, it provides the much needed interoperability among assessments of animal welfare. It enables comparing the impact of practices and living conditions, policies and interventions, and the calculation of welfare footprints of animal-sourced products using a universal measurement unit.
ARTICLE | doi:10.20944/preprints202001.0289.v1
Subject: Engineering, Civil Engineering Keywords: tunnel entrance; crosswind; wind–train–track coupling dynamic model; transient response of aerodynamic load; sudden wind effect; traffic safety
Online: 24 January 2020 (15:07:07 CET)
Sudden variation of aerodynamic loads is the potential source of safety accidents of high-speed train (HST). As a follow-up investigation on the aerodynamic response of a HST that enters a tunnel under crosswind environment, this paper focuses on the transient response of a HST’s safety indices based on the train–track coupling interaction model. Firstly, a wind–train–track coupling dynamic model is proposed by introducing transient aerodynamic loads into the vehicle–track system. Secondly, the temporal evolution of safety coefficients indicates that the train’s safety risk increases during tunnel entry with crosswind. Results show that the derailment coefficients and wheel load reduction rate during tunnel entry are not only larger than those in open air but also those inside the tunnel due to the sudden disappearance of wind excitation at the tunnel entrance. In addition, the characteristic wind curve, which is the wind velocity against the train speed, is presented for application based on the current specification of the safety criteria threshold. The investigation will be useful in assessing the safety risk of a running train subjected to other aerodynamic attacks, such as the coupling effect of infrastructure scenario and crosswind in windy area.
ARTICLE | doi:10.20944/preprints202207.0417.v1
Subject: Environmental And Earth Sciences, Atmospheric Science And Meteorology Keywords: storm tracks; track density; cyclogenesis areas; climate variability and change; the North Atlantic Oscillation; the East Atlantic–West Russia pattern
Online: 27 July 2022 (10:00:33 CEST)
A better understanding of the expected future cyclonic activity, especially in the Mediterranean Basin in winter, is essential for developing scientifically based adaptation and mitigation methods to extreme precipitation and wind anomalies. The aim of this study is to analyze the change of winter cyclonic activity in the Mediterranean-Black Sea region, within the Atlantic–European region, at the beginning (as the recent historical period), middle and end of the 21st century. The projections are based on an ensemble of seven CMIP6 models, which showed the best consistency with NCEP/NCAR and ERA5 reanalysis, under the intermediate SSP2-4.5 and highest-emission SSP5-8.5 scenarios. The results show a consistent increase of the frequency of cyclones over Central Europe and the British Isles associated with the shift of cyclone tracks: norward from the Western Mediterranean region and southward from the Iceland Low. The latter leads to a decrease of the frequency in the north of the Atlantic–European region. At the same time, there is a reduction of the frequency of cyclones over the east of the Mediterranean Sea consistent with the decrease of cyclogenesis events. Area-averaged cyclone numbers in the Western and Eastern Mediterranean and the Black Sea subregions reduce to the end of the century under the highest-emission scenario, but not constantly and with a raise in the middle of the 21st century under both scenarios, which may be linked to the long-term multidecadal variability or regional features. In general, our study shows that the future winter cyclonic activity in the Mediterranean-Black Sea region responds unevenly to global climate changes, because regional and monthly features are important, as well as accounting for the long-term quasiperiodic variability.
ARTICLE | doi:10.20944/preprints201905.0260.v1
Subject: Environmental And Earth Sciences, Oceanography Keywords: Synthetic aperture radar (SAR); along-track interferometry (ATI); sub-pixel offset tracking (sPOT); COSMO-SkyMed (CSK); staring spotlight (ST); micro-motion (m-m); vibrations; frequency modes
Online: 21 May 2019 (11:33:59 CEST)
This research aims to estimate the micro-motion (m-m) of ships. The problem of motion and m-m detection of targets is usually solved using synthetic aperture radar (SAR) along-track interferometry (ATI) which is observed employing two radars spatially distanced by a baseline extended in the azimuth direction. This paper is proposing a new approach where the m-m estimation of ships, occupying thousands of pixels, is measured processing the information given by sub-pixel tracking generated during the coregistration process of several re-synthesized time-domain and overlapped sub-apertures. The SAR products are generated splitting the raw data, according to a small-temporal baseline strategy, observed by one single wide-band staring spotlight (ST) SAR image. The predominant vibrational modes of different ships are estimated and results are promising to extend this application in performing surveillance also of land-based industries activities. Experiments are performed processing one ST SAR image observed by the COSMO-SkyMed satellite system.