Academic literature on the topic 'Under rail paid'
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Journal articles on the topic "Under rail paid"
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Chang, Chao, Liang Ling, Zhaoling Han, Kaiyun Wang, and Wanming Zhai. "High-Speed Train-Track-Bridge Dynamic Interaction considering Wheel-Rail Contact Nonlinearity due to Wheel Hollow Wear." Shock and Vibration 2019 (October 31, 2019): 1–18. http://dx.doi.org/10.1155/2019/5874678.
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Wheel hollow wear is a common form of wheel-surface damage in high-speed trains, which is of great concern and a potential threat to the service performance and safety of the high-speed railway system. At the same time, rail corridors in high-speed railways are extensively straightened through the addition of bridges. However, only few studies paid attention to the influence of wheel-profile wear on the train-track-bridge dynamic interaction. This paper reports a study of the high-speed train-track-bridge dynamic interactions under new and hollow worn wheel profiles. A nonlinear rigid-flexible coupled model of a Chinese high-speed train travelling on nonballasted tracks supported by a long-span continuous girder bridge is formulated. This modelling is based on the train-track-bridge interaction theory, the wheel-rail nonelliptical multipoint contact theory, and the modified Craig–Bampton modal synthesis method. The effects of wheel-rail nonlinearity caused by the wheel hollow wear are fully considered. The proposed model is applied to predict the vertical and lateral dynamic responses of the high-speed train-track-bridge system under new and worn wheel profiles, in which a high-speed train passing through a long-span continuous girder bridge at a speed of 350 km/h is considered. The numerical results show that the wheel hollow wear changes the geometric parameters of the wheel-rail contact and then deteriorates the train-track-bridge interactions. The worn wheels can increase the vibration response of the high-speed railway bridges.
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Fang, Chao, Piao Dong, Yi-Ping Fang, and Enrico Zio. "Vulnerability analysis of critical infrastructure under disruptions: An application to China Railway High-speed." Proceedings of the Institution of Mechanical Engineers, Part O: Journal of Risk and Reliability 234, no. 2 (November 29, 2019): 235–45. http://dx.doi.org/10.1177/1748006x19889149.
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Considerable attention has been paid to the vulnerability of critical infrastructures because of the increasing occurrence of disruptive events, such as man-made or natural disasters. Even small disruptions could eventually affect the normal function of infrastructure systems. Enhancing the reliability of these systems and their robustness to disruptions is necessary and urgent. High-speed rail is a critical infrastructure that is subject to various disruptions, including component aging, malicious attacks, natural disasters, and demand surges. In this study, we analyze the topological centrality indicators of China Railway High-speed network using network theory and take real train flow information for assessing the importance of network components in terms of vulnerability to disruption. By Monte Carlo simulation, we analyze the risk of the China Railway High-speed network under random attacks and spatially localized failures. The significance of taking pre-actions for protecting critical infrastructures by mitigating its vulnerability to disruptions is emphasized.
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Djordjević, Boban, and Evelin Krmac. "Evaluation of Energy-Environment Efficiency of European Transport Sectors: Non-Radial DEA and TOPSIS Approach." Energies 12, no. 15 (July 28, 2019): 2907. http://dx.doi.org/10.3390/en12152907.
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Transport is recognized as a major energy consumer and environment pollutant. Recently scholars have paid considerable attention to the evaluation of transport energy and environmental efficiency (EEE). In this paper, the non-radial Data Envelopment Analysis (DEA) model was employed to evaluate EEE on a macro level—i.e., of European road, rail and air sectors. The evaluation was conducted under the joint production framework, which considers energy and non-energy inputs, and desirable and undesirable outputs for the last ten years period. To rank decision-making units and check the aptness of this non-radial DEA model in transport EEE evaluation, the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) method has been proposed. An empirical study has been conducted for as many European countries as possible, depending on availability of data. Based on the non-radial DEA model, it could be said that the level of EEE is improving for the road sector, while many evaluated countries have low EEE for the rail transport sector. Additionally, results have indicated that the TOPSIS method is more suitable than the non-radial DEA model in transport EEE evaluation and for identification of best practices.
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Knežević, Mirjana. "Passenger transport: The challenges in the modern world." Ekonomika 67, no. 2 (2021): 23–34. http://dx.doi.org/10.5937/ekonomika2102023k.
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In this paper, the author examines the domestic and international legal framework for the contract of carriage of passengers and its presence in different transport modes and offers a response to the current challenges. The purpose of the paper is to analyze the international and domestic regulations and present the rights and obligations of contracting parties in order to facilitate its application in the emerging practice. The author recognizes passenger transport as a field full of modern challenges caused by novel, still under-researched risks to passengers' health. Special attention is paid to the contract of passenger carriage by rail. The advantages of this transport mode are examined, the obligations of railway carriers and passengers are presented, while the obligation of the railway carrier to accept transporting any interested person if they have vacancies is underlined. The analysis focuses on the significance of the contract of passenger transport in the modern environment where risks to passengers' healthcare present. The author recognizes passenger transport by rail as a convenient and perspective branch of passenger transport for both international and domestic passenger transport. This sort of passenger transport already has the potential to respond to the challenges of preserving and strengthening the protection of passenger's rights, above all the right to safe and secure transportation.
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McKay, Tracey, Zach Simpson, and Naeem Patel. "Spatial politics and infrastructure development: Analysis of historical transportation data in Gauteng - South Africa (1975–2003)." Miscellanea Geographica 21, no. 1 (March 1, 2017): 35–43. http://dx.doi.org/10.1515/mgrsd-2017-0003.
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Abstract If South Africa’s Gauteng Province is to become a more ‘sustainable’, urbanised region, attention needs to be paid to building a transportation network that aligns with sustainable development principles. Currently, public transport passenger levels are low, whilst the geographical area it serves is large and becoming larger. This study analysed the long term, historical transportation trends of Gauteng by comparing four transport studies undertaken between 1975 and 2003. It reveals that an adherence to the ‘predict and provide’ transportation planning model has systematically enhanced road infrastructure over rail, and private over public transport. Effective, efficient and low cost public transport has been systematically under-provisioned; while a reliance on private vehicles is now entrenched and systemic. Racial segregation, spatial apartheid and weak urban land use planning, has resulted in an entrenched, low-density urban sprawl. Lastly, there is the need to collect comparable, longitudinal transportation data, if the successes and failures of policies are to be monitored.
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Guo, Beibei, and Jinchuan Ke. "The Impacts of High-speed Rail on Sustainable Economic Development: Evidence from the Central Part of China." Sustainability 12, no. 6 (March 19, 2020): 2410. http://dx.doi.org/10.3390/su12062410.
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To give full play to the role of high-speed rail (HSR) in promoting sustainable economic development, the models that can calculate and describe the impacts of HSR on the sustainable economy are required. However, little attention has been paid so far to building such models. To address this, the paper puts forward the definition of sustainable economic development, especially that of China. Based on the definition, the paper proposes the indicators of sustainable economic development for China from industry and labor force perspectives. Compared with the previous literature, these indicators take into account the behavior of enterprises and labor forces as individuals rather than as groups, which is more explanatory. HSR, as the main factor to improve the level of transportation technology and accessibility, is incorporated into the analytical framework. Then, we build decision-making behavior models of single enterprise and labor force under market equilibrium to get the relationship between HSR and indicators. Compared with the previous literature, the methods within the paper not only fully consider the interests of enterprises and labor forces, but also considers the interaction between industries and the trade of commodities in different cities/regions. The evidence from the central part of China shows that the model can effectively reveal the relationship between HSR and indicators. The paper gives new perspectives to study the relationship between HSR and sustainable economic development. Based on the findings herein, we offer recommendations for how HSR can promote sustainable economic development effectively.
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Petrykin, Nikolai N. "Gendarme railway police: experience of mass transportation in the territory of the Kursk Governorate (1896–1914)." Tambov University Review. Series: Humanities, no. 187 (2020): 110–19. http://dx.doi.org/10.20310/1810-0201-2020-25-187-110-119.
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We contribute to the discussion of the results of a significant resettlement policy, the role of the gendarme railway police in its implementation and the role of the gendarme structure in the history of the Russian Empire. For the first time, we make an attempt to disclose the mechanism of the gendarme railway police in implementing the state’s resettlement policy in the area of migration flows on the materials of the Kursk Governorate, taking into account the existing rail-way network and the structure of the gendarme police departments. Based on the materials of the State Archive of the Russian Federation and local archives, the issues of legal regulation of mass railway transportation by the gendarme railway police are considered. An analysis of the gen-darme’s paperwork based on the materials of the Kursk branch of the gendarme police department of the Moscow-Kursk railway is given, aspects of interaction with the railway administration, local authorities, and the general police are highlighted. We trace the change and expansion of the duties of the railway gendarmes in connection with changes in the resettlement policy during the period under review and highlight the main stages. Particular attention is paid to issues of public safety in the context of criminalization on the railways. We show the role of the gendarme railway police in ensuring the sanitary and epidemiological welfare of passengers, taking into account the situation in the Kursk Governorate. Particular attention is paid to the influence of resettlement processes on the internal organizational, personnel aspects of the activities of the railway police, the dependence of the employee’s spiritual and moral condition on personal choice. We draw conclusions on the significance, scale, diversity of the gendarme railway police activities during the implementation of the resettlement policy.
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Mazov, Yuriy Nikolaevich, Aleksey Alekseevich Loktev, and Vyacheslav Petrovich Sychev. "Assessing the influence of wheel defects of a rolling stockon railway tracks." Vestnik MGSU, no. 5 (May 2015): 61–72. http://dx.doi.org/10.22227/1997-0935.2015.5.61-72.
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Transfer of the load from the wheels on the rail occurs at a very small area compared with the size of the wheels and rails. The materials near this site have a very large voltage. Determination of contact stresses is complicated by the fact that the magnitude of these stresses in the rails under actually revolving wheel load exceeds the yield and compressive strength of modern rail steel. We should note that the metal of the rail head, experiencing contact stresses, especially when the location of the pads is closer to the middle of the rail head, works in the conditions close to the compression conditions, and therefore can withstand higher voltage without plastic deformation than the standard compressible sample. But, as a rule, the observed hardening of the metal in the zone of contact stresses and lapping at the edges of the rail head indicates the presence of plastic deformation and, consequently, higher stresses in the wheel-rail contact zone than the yield strength of the metal rail even in the conditions of its operation in the rail head.The use of the design equations derived on the basis of the Hertz theory for metal behavior in elastic stage, is valid. The reason is that each individual dynamic application of wheel loads on the rail is very short, and the residual plastic deformation from the individual loads of the pair of wheels on the rail is actually small. This elastic-plastic deformation of the rail becomes visible as a result of gradual gaining of a missed tonnage of rails and wheels respectively. Irregularities on the running surface of the wheels are of two types. The most common are the so-called continuous bumps on the wheel, when due to the uneven wear of rail the original shape of the wheel across the tread surface distorts. But nowadays, more and more often there occur isolated smooth irregularities of the wheel pairs, due to the increased wear of the wheel because of the stopping and blocking of wheels of the vehicles - slides (potholes), etc.The motion of the wheels with irregularities on the surface of the rail leads to vertical oscillation of the wheel, resulting in the forces of inertia, which is an additional load on the rail. In case of movement of the wheel with isolated roughness on the tread surface of the slide there is a strike, having a very large additional impact on the rail. Such attacks can cause kinked rails, especially in the winter months when there is increased fragility of rail steel, because of lowered temperatures. This is an abnormal phenomenon and occurs relatively rarely, at a small number of isolated irregularities on a wheel of the rolling stock. As correlations connecting the contact force and local deformation in the interaction of the wheel-rail system, we use the quasi-static Hertz’s model, linear-elastic model and two elastoplastic contact models: Alexandrov-Kadomtsev and Kil’chevsky. According to the results of Loktev’s studies ratios of the contact Hertz’s theory are quite suitable for modeling the dynamic effects of wheel and rail for speeds up to 90 km/h for engineering calculations. Since the contact surface is homogeneous and isotropic, the friction forces in the contact zone are not taken into account, the size of the pad is small compared to the dimensions of the contacting bodies and characteristic radii of curvature of the undeformed surfaces, the contacting surfaces are smooth.When train is driving, the position of the wheelset in relation to the rails varies con- siderably, giving rise to different combinations of the contact areas of the wheel and rail. Even assuming constant axial load the normal voltage will vary considerably because of the differences in the radii of curvature of the contacting surfaces of these zones. Thus, the proposed method allows evaluating the influence of several types of wheel defects on the condition of the rail and the prospects of its use in the upper structure of a railway track on plots with different speed and traffic volumes. Also the results can be used to solve the inverse of the considered problems, for example, when designing high-speed highways, when setting the vehicle speed and axle load, and the solution results are the parameters of the defects, both wheelsets and the rails, in case of which higher require- ments for the safe operation of railways are observed.
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LU, CHIH-WEN, and CHING-MIN HSIAO. "A COMPACT HIGH-SPEED LOW-POWER RAIL-TO-RAIL BUFFER AMPLIFIER FOR STEP-PULSE SIGNALS." Journal of Circuits, Systems and Computers 19, no. 06 (October 2010): 1181–97. http://dx.doi.org/10.1142/s0218126610006815.
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A compact high-speed low-power rail-to-rail buffer amplifier, which is suitable for driving heavy capacitive loads, is proposed. The buffer amplifier is composed of a pair of push-pull output transistors with two feedback loops consisting of a pair of complementary error amplifiers and a pair of complementary common-source amplifiers. The buffer draws little current while static but has a large driving capability while transient. A mutual bias scheme is also proposed to reduce the power consumption and the die area for LCD applications. An experimental prototype buffer amplifier implemented in a 0.35 μm CMOS technology demonstrates that the settling time is 1.5 μs for a voltage swing of 0.1 ~ (VDD–0.1) V under a 600 pF capacitance load. Quiescent current of 4 μA is measured. The area of this buffer is 32 × 109 μm2.
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Liu, Peijie, Yanming Quan, Junjie Wan, and Lang Yu. "Experimental Investigation on the Wear and Damage Behaviors of Machined Wheel-Rail Materials under Dry Sliding Conditions." Materials 14, no. 3 (January 23, 2021): 540. http://dx.doi.org/10.3390/ma14030540.
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Rail grinding and wheel turning can effectively remove surface defects and unevenness, which is a crucial process for the safe and smooth operation of trains. Machined surface integrity of wheel/rail materials significantly influences their tribological property. In this study, firstly, the rail blocks were ground via a cylindrical grinding machine, and the wheel rings were turned by a computer numerical control (CNC) lathe with varied parameters. Then, the sliding wear and damage characteristics of the machined wheel/rail samples under dry conditions were studied by virtue of a block-on-ring tribometer. The results show that the surface microhardness of the ground rail blocks is larger than that of wheel rings, while the surface roughness and the thickness of the subsurface plastic deformation layer (SPDL) of rail blocks are much smaller than those of wheel rings. After sliding, the surface microhardness of wheel/rail samples increases remarkably. The thickness of the SPDL, the wear loss, and the increase degree of surface microhardness of rail blocks are larger than those of wheel rings. Surface microhardness, roughness and the SPDL of the machined wheel/rail samples impose a combined influence on the anti-wear property, and the tribological pair with proper initial surface roughness and microhardness engenders the smallest amount of total wear loss.
Dissertations / Theses on the topic "Under rail paid"
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Marte, Davide. "Life cycle assessment e analisi economica dell'utilizzo di pneumatici fuori uso nelle linee ferroviarie." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2015. http://amslaurea.unibo.it/8555/.
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La presente tesi si propone di determinare quale sia la situazione del mercato italiano e spagnolo sui pneumatici fuori uso (PFU) e quale sia il migliore metodo di costruzione degli elementi elastici da PFU. I risultati dell'analisi di mercato mostrano che l'introduzione del principio di responsabilità del produttore, introdotto in Italia solo nel 2011, sta portando ottimi risultati, e il problema di raccolta degli PFU è in via di risoluzione. Gli studi dinamici documentano che gli under rail paid (URP) costruiti da PFU rispettano tutte le necessità tecniche per l'utilizzo nelle linee ferroviarie sia convenzionali che ad alta velocità. Invece il Life Cycle Assessment (LCA) dimostra che il processo di costruzione degli URP da PFU decostruiti impatta meno rispetto a quello dei PFU triturati. I risultati del Life Cycle Cost (LCC) fanno propendere per un utilizzo degli URP nelle vie ferroviarie in quanto si ha una diminuzione dei costi di manutenzione.
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Tecklenburg, Gerhard. "Design of body assemblies with distributed tasks under the support of parametric associative design (PAD)." Thesis, University of Hertfordshire, 2011. http://hdl.handle.net/2299/5809.
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This investigation identifies how CAD models of typical automotive body assemblies could be defined to allow a continuous optimisation of the number of iterations required for the final design and the number of variants on the basis of Parametric Associative Design (PAD) and how methodologies for the development of surfaces, parts and assemblies of the automotive body can be represented and structured for a multiple re-use in a collaborative environment of concept phase of a Product Evolution (Formation) Process (PEP). The standardisation of optimised processes and methodologies and the enhanced interaction between all parties involved in product development could lead to improve product quality and reduce development time and hence expenses. The fundamental principles of PAD, the particular methodologies used in automotive body design and the principles of methodical development and design in general are investigated. The role which automotive body engineers play throughout the activities of the PEP is also investigated. The distribution of design work in concept teams of automotive body development and important methodologies for the design of prismatic profile areas is critically analysed. To address the role and distribution of work, 25 group work projects were carried out in cooperation with the automotive industry. Large assemblies of the automotive bodies were developed. The requirements for distributed design work have been identified and improved. The results of the investigation point towards a file based, well structured administration of a concept design, with a zone based approach. The investigation was extended to the process chain of sections, which are used for development of surfaces, parts and assemblies. Important methods were developed, optimised and validated with regard to an update safe re-use of 3D zone based CAD models instead of 2D sections. The thesis presents a thorough description of the research undertaken, details the experimental results and provides a comprehensive analysis of them. Finally it proposes a unique methodology to a zone based approach with a clearly defined process chain of sections for an update-safe re-use of design models.
Conference papers on the topic "Under rail paid"
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Chen, Rong, Ping Wang, and Likang Guo. "Noise and Vibration Reduction Performance Test of Rubber Damping Pad Under Slab Track in High Speed Railway." In 2013 Joint Rail Conference. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/jrc2013-2569.
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Rubber damping pad under ballastless slab track can isolate structure vibration and noise so as to reduce stress and wear of railway track components. In order to make scientific evaluation on the influence of rubber damping pad on the dynamic response of the track structure, focusing on the engineering practice of Chengdu-GuanDujiangyan high-speed railway, comparative test of slab track with and without rubber damping pad is carried out by using acceleration sensors, acoustic sensors, and dynamic data acquisition system. Spectrum analysis of vibration acceleration and noise test results shows that rubber damping pad under track slab can greatly isolate the substructure vibration of the track, the bridge vibration and ground vibration; vibration level of the base slab under the pad is reduced by about 20.1dB; the rubber damping pad can reduce some of the structure noise caused by the bridge structure vibration, but it has no significant effect on noise reduction of the whole system due to the influences of EMU pantograph’s arc noise, severe air turbulence noise and field test environment.
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Kim, Eun, Sin Chu Yang, and Seung Yup Jang. "Investigation and Prediction of Stiffness Increase of Resilient Rail Pad due to Train and Environmental Load in High-Speed Railway." In 2015 Joint Rail Conference. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/jrc2015-5789.
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The rail pad stiffness is one of key design parameters of the track structure, affecting the load distribution along the rail and the dynamic behavior of the track. The rail pad stiffness, however, can be increased under accumulated train load and environmental load, i.e., temperature change, due to the nature of resilient rubber. This study investigates the causes and prediction model of the stiffness increase of the resilient rail pads used in the ballasted and concrete slab track in high-speed railway. For this purpose, in-situ rail pads were taken from several sites, and the static and dynamic stiffness was measured. Also, the repeated load test and accelerated heat aging test on new rail pads in the laboratory have been performed. Based on the test data, proposed is a mathematical model for predicting the increase of the rail pad stiffness according to passing tonnage and elevated temperature.
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Liu, Long, Hongzi Fei, and Jingtao Du. "Analysis of Pilot Injection Effects on Combustion Noise in PPCI Diesel Engines." In ASME 2016 Internal Combustion Engine Division Fall Technical Conference. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/icef2016-9356.
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With the common-rail fuel injection systems widely used in diesel engines, the pilot injection strategy has been paid more attention for suppressing pollutants emissions and combustion noise. Using pilot injection strategies, leaner and more homogenous mixture formed in pilot spray results in the combustion process partially fulfill Premixed Charge Compression Ignition (PCCI). Therefore the combustion process of diesel engines with pilot injection strategy can be considered as partial PCCI (PPCI). Pilot injection causes the in-cylinder temperature increase before main injection, which shortens the ignition delay of main spray and consequently reduces the combustion noise, so that the pilot injection has potential to extend PPCI combustion model to high load operation. However, the mechanism of pilot injection effects on the combustion noise has not been fully understood, consequently it is difficult to estimate the lower combustion noise among different pilot injection conditions, that results in difficult selection of the pilot injection parameters in proper way. Thus, in this study, experiments were performed on a single-cylinder DI-diesel engine with pilot and main injection under high load operating conditions. The synthesized in-cylinder pressure levels (CPLs) in different frequency ranges as a novel method were proposed to analyze the pilot injection effects on combustion noise. The results reveal that pilot spray combustion mainly influences the high frequency combustion noise, and the later pilot injection timing causes the higher combustion noise. In the case of the short dwell between pilot and main injection, the increasing pilot injection quantity enhances the high frequency combustion noise. Meanwhile because of the pilot injection quantity increase, decrease of main injection quantity leads to lower combustion noise in middle frequency range.
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do Carmo, Thiago B., J. Riley Edwards, Ryan G. Kernes, Bassem O. Andrawes, and Chris P. L. Barkan. "Laboratory and Field Investigation of the Rail Pad Assembly Mechanistic Behavior." In 2014 Joint Rail Conference. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/jrc2014-3784.
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To achieve the performance demands due to growing heavy-haul freight operations and increased high-speed rail service worldwide, advancements in concrete crosstie fastening systems are required. A mechanistic design approach based on scientific principles and derived from extensive laboratory and field investigation has the potential to improve the current best practices in fastening system design. The understanding of failure modes and effects on each component, associated with an improved understanding of load distribution and mechanical behavior, will ultimately increase production and operational efficiency while reducing unscheduled maintenance, track outages, and unplanned additional costs. Improvements on the rail pad assemblies, the components responsible for attenuating loads and protecting the concrete crosstie rail seat, will enhance the safety and efficiency of the track infrastructure. Understanding the mechanistic behavior of rail pad assemblies is critical to improving the performance and life cycle of the infrastructure and its components, which will ultimately reduce the occurrence of potential failure modes. Lateral, longitudinal, and shear forces exerted on the components of the fastening system may result in displacements and deformations of the rail pad with respect to the rail seat and rail base. The high stresses and relative movements are expected to contribute to multiple failure mechanisms and result in an increased need for costly maintenance activities. Therefore, the analysis of the mechanics of pad assemblies is important for the improvement of railroad superstructure component design and performance. In this study, the lateral displacement of this component with respect to the rail base and rail seat is analyzed. The research ultimately aims to investigate the hypothesis that relative displacement between the rail pad and rail seat occurs under realistic loading environments and that the magnitude of the displacement is directly related to the increase in wheel loads.
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Rodriguez, Oscar O., Arturo A. Fuentes, Constantine Tarawneh, and Robert E. Jones. "Hysteresis Heating of Railroad Bearing Thermoplastic Elastomer Suspension Element." In 2017 Joint Rail Conference. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/jrc2017-2257.
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Thermoplastic elastomers (TPE’s) are increasingly being used in rail service in load damping applications. They are superior to traditional elastomers primarily in their ease of fabrication. Like traditional elastomers they offer benefits including reduction in noise emissions and improved wear resistance in metal components that are in contact with such parts in the railcar suspension system. However, viscoelastic materials, such as the railroad bearing thermoplastic elastomer suspension element (or elastomeric pad), are known to develop self-heating (hysteresis) under cyclic loading, which can lead to undesirable consequences. Quantifying the hysteresis heating of the pad during operation is therefore essential to predict its dynamic response and structural integrity, as well as, to predict and understand the heat transfer paths from bearings into the truck assembly and other contacting components. This study investigates the internal heat generation in the suspension pad and its impact on the complete bearing assembly dynamics and thermal profile. Specifically, this paper presents an experimentally validated finite element thermal model of the elastomeric pad and its internal heat generation. The steady-state and transient-state temperature profiles produced by hysteresis heating of the elastomer pad are developed through a series of experiments and finite element analysis. The hysteresis heating is induced by the internal heat generation, which is a function of the loss modulus, strain, and frequency. Based on previous experimental studies, estimations of internally generated heat were obtained. The calculations show that the internal heat generation is impacted by temperature and frequency. At higher frequencies, the internally generated heat is significantly greater compared to lower frequencies, and at higher temperatures, the internally generated heat is significantly less compared to lower temperatures. However, during service operation, exposure of the suspension pad to higher loading frequencies above 10 Hz is less likely to occur. Therefore, internal heat generation values that have a significant impact on the suspension pad steady-state temperature are less likely to be reached. The commercial software package ALGOR 20.3TM is used to conduct the thermal finite element analysis. Different internal heating scenarios are simulated with the purpose of obtaining the bearing suspension element temperature distribution during normal and abnormal conditions. The results presented in this paper can be used in the future to acquire temperature distribution maps of complete bearing assemblies in service conditions and enable a refined model for the evolution of bearing temperature during operation.
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Rodriguez, Oscar O., Juan Carbone, Arturo A. Fuentes, Robert E. Jones, and Constantine Tarawneh. "Heat Generation in the Railroad Bearing Thermoplastic Elastomer Suspension Element." In 2016 Joint Rail Conference. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/jrc2016-5823.
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The main purpose of this ongoing study is to investigate the effect of heat generation within a railroad thermoplastic elastomer suspension element on the thermal behavior of the railroad bearing assembly. Specifically, the purpose of this project is to quantify the heat generated by cyclic loading of the elastomer suspension element as a function of load amplitude, loading frequency, and operating temperature. The contribution of the elastomer pad to the system energy balance is modeled using data from dynamic mechanical analysis (DMA) of the specific materials in use for that part. DMA is a technique that is commonly used to characterize material properties as a function of temperature, time, frequency, stress, atmosphere or a combination of these parameters. DMA tests were run on samples of pad material prepared by three different processes: injection molded coupons, transfer molded coupons, and parts machined from an actual pad. The results provided a full characterization of the elastic deformation (Energy Storage) and viscous dissipation (Energy Dissipation) behavior of the material as a function of loading frequency, and temperature. These results show that the commonly used thermoplastic elastomer does generate heat under cyclic loading, though the frequency which produces peak heat output is outside the range of common loading frequency in rail service. These results can be combined with a stress analysis and service load measurements to estimate internally generated heat and, thus, enable a refined model for the evolution of bearing temperature during operation.
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Nguyen, Thompson V., Stefano Mariani, Robert R. Phillips, Piotr Kijanka, Francesco Lanza di Scalea, and Wieslaw J. Staszewski. "Non-Contact Ultrasonic Guided Wave Inspection of Rails." In ASME 2013 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/imece2013-63029.
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The University of California at San Diego (UCSD), under a Federal Railroad Administration (FRA) Office of Research and Development (R&D) grant, is developing a system for high-speed and non-contact rail integrity evaluation. A prototype using an ultrasonic air-coupled guided wave signal generation and air-coupled signal detection, in pair with a real-time statistical analysis algorithm, is being developed. This solution presents an improvement over the previously considered laser/air-coupled hybrid system because it replaces the costly and hard-to-maintain laser with a much cheaper, faster, and easier-to-maintain air-coupled transmitter. This system requires a specialized filtering approach due to the inherently poor signal-to-noise ratio of the air-coupled ultrasonic measurements in rail steel. Various aspects of the prototype have been designed with the aid of numerical analyses. In particular, simulations of ultrasonic guided wave propagation in rails have been performed using a Local Interaction Simulation Approach (LISA) algorithm. Many of the system operating parameters were selected based on Receiver Operating Characteristic (ROC) curves, which provide a quantitative manner to evaluate different detection performances based on the trade-off between detection rate and false positive rate. Experimental tests have been carried out at the UCSD Rail Defect Farm. The laboratory results indicate that the prototype is able to detect internal rail defects with a high reliability. A field test will be planned later in the year to further validate these results. Extensions of the system are planned to add rail surface characterization to the internal rail defect detection.
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Rapp, Christopher T., J. Riley Edwards, Marcus S. Dersch, Christopher P. L. Barkan, Jose Mediavilla, and Brent M. Wilson. "Measuring Concrete Crosstie Rail Seat Pressure Distribution With Matrix Based Tactile Surface Sensors." In 2012 Joint Rail Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/jrc2012-74092.
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A sustained increase in gross rail loads and cumulative freight tonnages, as well as increased interest in high and higher-speed passenger rail development in the United States, is placing an increasing demand on railway infrastructure. According to a railway industry survey conducted by the University of Illinois at Urbana-Champaign (UIUC), rail seat deterioration (RSD) was identified as one of the primary factors limiting concrete crosstie service life. Therefore, it can be seen that there is a need for infrastructure components with increased strength, durability, and ability to maintain the tighter geometric track tolerances under demanding loading conditions. Researchers have hypothesized that localized crushing of the concrete rail seat is one of five potential mechanisms that contribute to RSD. Therefore, to better understand this mechanism, UIUC is utilizing a matrix based tactile surface sensor (MBTSS) to quantify the forces acting at the interface between the bottom of the rail pad and the concrete tie rail seat. The MBTSS measures the forces and distribution of pressure as a load is applied to the rail seat. Preliminary laboratory testing has shown that higher modulus rail pads distribute forces poorer than lower modulus rail pads, leading to localized areas with high contact pressure and a higher probability of crushing. Testing has also shown that as the lateral/vertical (L/V) force ratio increases, the pressure on the field side of the rail seat also increases, possibly accelerating RSD. The objective of future field testing is to be able to validate the assumptions made from this preliminary laboratory data. Data collected and analyzed throughout this research project will provide valuable insight into developing future concrete crosstie and fastening system component designs that meet the operational and loading demands of high speed rail and joint passenger/freight corridors.
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Choi, Dong-Ho, Di Mu, Chunyan Ma, Min-Wo Park, and Ji-Hoon Lim. "Random Analysis of the Safety of a High-Speed Train through a Bridge under Earthquake." In IABSE Congress, New York, New York 2019: The Evolving Metropolis. Zurich, Switzerland: International Association for Bridge and Structural Engineering (IABSE), 2019. http://dx.doi.org/10.2749/newyork.2019.2055.
Full textAbstract:
<p>The widely use of bridge structures in modern high-speed railway makes the possibility that a train face to an earthquake when it’s running on a bridge increased. The running safety of the train requires more research attention to be paid. This study investigated the effect of bridge properties on the running safety of a high- speed train under earthquakes using a fast calculation approach. The train-track-bridge (TTB) system is simplified as a three-dimensional model for the dynamic analysis. The rigid contact between rails and wheels is considered, while the direct coupling iteration approach is adopted to solve the dynamic responses of the TTB system. The track irregularities, wheel hunting motion, and multi-support earthquake, which considers the time lag between the seismic waves at different supports, are considered as the excitations to the TTB system. The randomness of the excitations is considered by the pseudo-excitation method (PEM) and the statistical results of the TTB system random responses are obtained. The derailment factor and the off-load factor are used to evaluate the running safety of the train. In the case study, the damping ratio, pier height, and track eccentricity are considered as the various parameters of the bridge properties. Through the PEM analysis, the mean value and standard deviation of the running safety factors were obtained used to evaluate the running safety of the train under an earthquake condition. The evaluation approach for the running safety used in this study can help the engineers to simply check the designs of the railway bridges without performing large time cost calculation work.</p>
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Piestrzyński, Adam, Jadwiga Pieczonka, and Edward Chruściel. "Model for Long-Term Stabilization and Isolation of Low Level Uranium Waste." In ASME 2001 8th International Conference on Radioactive Waste Management and Environmental Remediation. American Society of Mechanical Engineers, 2001. http://dx.doi.org/10.1115/icem2001-1261.
Full textAbstract:
Abstract Problems arising from uranium dispersion from mines and mine tailings, and the remediation of uranium contaminated areas, are discussed in this paper. In an experimental remediation study, a mixture of 70 vol.% of uraniferous mining wastes and 30 vol.% of a natural ceramic were used. The preliminary observations are discussed, and a model is proposed for the long term stabilization of mining tailings. Observations and monitoring of contaminated sites carried out during the last 25 years have revealed local impacts of uranium on the environment in Lower Silesia, Poland. Uranium pollution is limited to waste dumps, mine tailings, and their close vicinities at Kowary Podgórze, Radoniów, Kopaniec and Kletno. Uranium dispersion takes place mechanically due to transport by river waters, chemically by rain and ground waters, and anthropogenically when the wastes are utilized in construction. Floods are an additional mechanism responsible for the mechanical dispersion of uranium. As a result of these uranium transport mechanisms, in order to minimize the impacts of uranium on the environment, the covering of dumps with non-radioactive material is suitable only for sites located away from populated areas. Redox reactions have been observed at the Kowary tailings. During these reactions, iron hydroxide (goethite), hematite, and gypsum, are precipitated as solids. These observations provide a good prognosis for the long-term stabilization of radionuclides which can be incorporated into proposals for the construction of tailings sites. Using Eh-pH diagrams (system U-C-O-H, 25°C, 1 bar), UO2 is stable over the whole range of naturally occurring pHs, and is affected by Eh only in the range −0.4 to +0.1 volts in acidic environments, and below −0.4v in basal environments. BaSO4 and RaSO4 are stable under almost the same conditions as UO2. An environmentally significant redox boundary (FeS2 versus Fe2O3) occurs in the middle of the UO2 stability field. The geochemical and environmental behaviour of the elements discussed above suggest a mechanism for stabilizing radionuclides within stored wastes. The solidification of wastes should occur concurrently with naturally occurring redox reactions. During oxidation, an active iron-hydroxide gel is produced. This gel is then dehydrated and converted into limonite (a mixed compound), a monohydrate (goethite), hydro-hematite (Fe2O3·1/2H2O) and hematite (Fe2O3). This reaction occurs in neutral or weakly acidic environments. A key problem in the proposed remediation project, therefore, is pH stabilization in order to maintain the required environment for oxidation and cementation reactions. In order to achieve such an environment and to stabilize the reactions, a construction method is proposed for new waste storage systems, based on mixed layers of waste and barrier components composed of natural materials. The presence of CaO or Ca(OH)2 and anhydrite in the proposed internal membrane will reduce the vertical migration of sulphates. Redox reactions will be responsible for the secondary precipitation (reduction) of uranyl. These same reactions occur naturally during the precipitation of uranium ores. Iron oxidation is the other process in the redox pair required to reduce [UO2]+2 to UO2. The resultant pitchblende is insoluble in normal oxidizing environments. To minimize the dissolution of UO2 by sulphuric acid generated during the iron oxidation reaction, the construction of pH active membranes containing calcium oxide or hydroxide are recommended. These compounds will react with the free acid to precipitate gypsum. Although several elements can be mobilized as a result of oxidation, radium remains in insoluble solid phases such as the common Ca, Ba and Sr sulphates.