bluuebunny/crossref_metadata_2025 huggingface dataset:
Speculation without oil stockpiling as a signature: a dynamic perspective
Authors: Pierru Axel , Babusiaux Denis
Published: November 2010

According to the standard analysis of commodity prices, stockpiling is a necessary signature of speculation. This paper develops an approach suggesting that speculation may temporarily (e.g. during a few months) push crude oil prices above the level justified by physical‐market fundamentals, without necessarily resulting in a significant increase in oil inventories. Looking beyond debate on the value of oil‐demand price‐elasticity, showing a demand curve makes sense only if we consider a fixed time horizon (e.g. short‐run). The scenario of oil demand slowly but continuously adjusting to a price fuelled by speculation implies that price elasticity of demand is an increasing function of the time horizon considered. Short‐ and long‐run elasticities can then be used to calibrate this function. A very low very‐short‐run price elasticity suggests that an exogenously‐driven rise in crude oil price has a very slight impact on demand in the very short run and therefore, with supply constant, leads to a minimal increase in inventories. This interpretation differs from the traditional view according to which storage of just a few barrels is enough to raise prices when elasticity is very low. We present several analytical and numerical illustrations (with oil‐demand adjustment following Gompertz, logistic and exponential paths). The role that speculation may have played in recent movements in oil prices is also discussed.
Networked Assembly of Affine Physical System Models
Authors: Motato E. , Radcliffe C.
Published: November 2010

Engineering design is evolving into a global strategy that distributes engineering effort to team members around the world. Because modern engineering design uses analytical models, model information must be distributed globally through computer networks. This strategy would be improved if component suppliers were able to efficiently provide dynamic models of supplied components. Furthermore, to use these component models, they must be efficiently assembled to obtain a dynamic model of a product using them. Four characteristics are needed to enable this distribution and assembly process. These characteristics are a unique standard model format, an exchange of model information through a single-query network transmission, external component models protecting proprietary internal design details, and, finally, a recursive assembly process. The modular model assembly method (MMAM) (Radcliffe et al., 2009, “Networked Assembly of Mechatronic Linear Physical System Models,” ASME J. Dyn. Syst., Meas., Control, 131, p. 021003) is a model assembly algorithm that satisfies these requirements. The MMAM algorithm assembles linear physical system models with dynamic stiffness matrices. In an affine system, deviations in the inputs and outputs exhibit a proportional relationship, but the outputs of the system are nonzero at zero input (Buck and Willcox, 1971, Calculus of Several Variables, Houghton Mifflin, Boston). One motivation for developing a process to assemble affine systems is the wide use of such models resulting from local linearization of general differentiable nonlinear physical system models about a nonzero, but constant, operating point. This paper provides the first general approach to the “operating point problem,” where the operating points of each individual component are solved as a function of the desired operating point of the model of an assembly of those components. The solution of this problem allows the assembly of linearized system models at any requested system operating point. This paper extends the MMAM to nonlinear affine system models. The MMAM uses internet agents to provide external models of components when requested by either users or other model agents. Assembly agents use the models provided by component agents to build an analytical model using models provided by component agents and assembly constraints within the assembly model agent. MMAM models are supplied in a standard form that allows an assembly agent to put together efficiently a model of the assembly that is also in the standard form. The process is recursive and facilitates hierarchical use of agents to efficiently build assemblies of assemblies to any level of complexity.
Transfer Matrix Modeling of Systems With Noncollocated Feedback
Authors: Krauss Ryan W. , Book Wayne J.
Published: November 2010

The transfer matrix method (TMM) can be a powerful tool for modeling flexible structures under feedback control. It is particularly well suited to modeling structures composed of serially connected elements. The TMM is capable of modeling continuous elements such as beams or flexible robot links without discretization. The ability to incorporate controller transfer functions into the transfer matrix model of the system makes it a useful approach for control design. A limitation of the traditional formulation of the TMM is that it can only model feedback where the actuators and sensors are strictly collocated. The primary contribution of this paper is an algorithm for modeling noncollocated feedback with the TMM. Two cases of noncollocated sensors are considered (upstream and downstream). The approach is experimentally verified on a flexible robot that has one upstream and one downstream sensor in its feedback loops.
Validation of Dynamic Models in the Time-Scale Domain
Authors: McCusker James R. , Danai Kourosh , Kazmer David O.
Published: November 2010

Model validation is the procedure whereby the fidelity of a model is evaluated. The traditional approaches to dynamic model validation consider model outputs and observations as time series and use their similarity to assess the closeness of the model to the process. A common measure of similarity between the two time series is the cumulative magnitude of their difference, as represented by the sum of squared (or absolute) prediction error. Another important measure is the similarity of shape of the time series, but that is not readily quantifiable and is often assessed by visual inspection. This paper proposes the continuous wavelet transform as the framework for characterizing the shape attributes of time series in the time-scale domain. The feature that enables this characterization is the multiscale differential capacity of continuous wavelet transforms. According to this feature, the surfaces obtained by certain wavelet transforms represent the derivatives of the time series and, hence, can be used to quantify shape attributes, such as the slopes and slope changes of the time series at different times and scales (frequencies). Three different measures are considered in this paper to quantify these shape attributes: (i) the Euclidean distance between the wavelet coefficients of the time series pairs to denote the cumulative difference between the wavelet coefficients, (ii) the weighted Euclidean distance to discount the difference of the wavelet coefficients that do not coincide in the time-scale plane, and (iii) the cumulative difference between the markedly different wavelet coefficients of the two time series to focus the measure on the pronounced shape attributes of the time series pairs. The effectiveness of these measures is evaluated first in a model validation scenario where the true form of the process is known. The proposed measures are then implemented in validation of two models of injection molding to evaluate the conformity of shapes of the models’ pressure estimates with the shapes of pressure measurements from various locations of the mold.
Bond-Graph Based Simulation of Thermodynamic Models
Authors: Brown Forbes T.
Published: November 2010

Conventional bond graphs are incompetent to handle thermodynamic systems with flowing fluid and phase change, such as heat engines and refrigeration cycles. Sophisticated bond-graph software for purposes of simulation is widely available for the systems addressable by conventional bond graphs, but heretofore there was no bond-graph software that could simulate the thermodynamic systems of concern. The author has previously published descriptions of a compatible extension to conventional bond graphs, which accommodates these systems through the use of what are known as convection bonds. Simulation of these models required ad hoc writing of the differential equations, however, a difficult task. The present brief announces the availability of software, based on a combination of convection and conventional bond graphs, which considerably expedites the simulation of thermodynamic and hybrid systems. The software is written in MATLAB® and is freely downloadable from the internet. It allows modeling and simulation to be carried out with a minimum knowledge of thermodynamics. Data characterizing the thermodynamic properties of 35 different pure substances and wet air are accessed as needed.
Estimated Weight Increase Resulting From Modifying European Trains to Meet Federal Railroad Administration Safety Rules
Authors: Scales Brian T.
Published: November 2010

It is claimed by the European train manufacturers that adapting existing European high-speed train technologies to satisfy the Safety Rules of the Federal Railroad Administration (FRA) for rail passenger vehicles to be operated in the USA would result in a significant and uneconomic weight increase. A methodology was required for the estimation of this weight increase so that performance calculations can be undertaken of European high-speed train technologies that have been modified to suit the FRA Safety Rules.
Developing Railway Higher Education in the European Union and United States
Authors: Lautala Pasi T. , Ma´ca´rio Rosa´rio , Pachl Jo¨rn , Edwards J. Riley , Sproule William J.
Published: November 2010

Congestion, emissions generated by transportation, increasing fuel costs and expanding demand for mobility have revived the interest for modern rail transportation throughout the world. Simultaneously, expansion of global trade and increasing demands for technology to improve the safety and productivity of the industry are creating a new environment that requires a different way of thinking when developing railway systems. Overall, the authors believe that current changes provide a fertile ground for institutions of higher education in the United States and the European Union (EU) to increase their transatlantic cooperation in education and research. Recent studies related to railway higher education have been undertaken in Europe and the United States. The European Rail Research Network of Excellence (EURNEX) conducted a study to develop and organize educational and training activities in participating higher education institutions. In Germany, a comprehensive inventory was conducted to define the current level of rail transportation activities in higher education institutions. In the United States, American Railway Engineering and Maintenance of Way Association (AREMA) conducted a study to determine the type and extent of rail education currently offered on campuses. In addition, a benchmarking study was performed by Michigan Tech University to investigate rail education and recruitment at universities with the objective to define the quantitative and qualitative demands for rail engineers by industry employers. This paper presents a synopsis of these past studies and introduces an on-going “TUNRail” project to “tune” and intensify the railway higher education knowledge exchange and collaboration between the EU and the United States.
Estimating Maintenance Costs for Mixed Higher Speed Passenger and Freight Rail Corridors
Authors: Zarembski Allan M. , Patel Pradeep
Published: November 2010

In order to reduce the cost of new intercity passenger rail corridors, the operation of higher speed passenger networks on existing freight corridors is being examined and considered. The issues to be addressed in such operations include the one-time upgrade of the track to allow for this higher speed passenger traffic and the ongoing maintenance costs necessary to maintain this track for the mixed higher speed passenger and freight operations. This latter issue is usually addressed in the access agreements for the corridor, and must include how these costs are to be shared. A recent US Federal Railroad Administration study specifically addressed the issue of “steady state” maintenance costs for mixed use corridors consisting on this class of higher speed passenger operations and concurrent freight operations, to include heavy axle load freight operations. The result of that study was a “planner’s handbook” for estimating these track maintenance costs, as part of the overall analysis of the feasibility and cost of operating higher speed passenger traffic on existing freight corridors. This paper presents the methodology used in the development of the methodology for estimating maintenance costs for mixed higher speed passenger and freight rail corridors (Classes 4, 5 and 6). Specifically, it addresses the estimation of these “steady state” infrastructure maintenance costs for a range of operating scenarios with different combination of passenger and freight traffic densities and operating speeds. These infrastructure costs include track, bridge and building (B&B), and communications and signal (C&S) costs. The resulting costs are presented as a set of cost matrices both in terms of a total cost per track mile and in terms of cost per passenger train mile. The cost matrices cover a range of combinations of traffic and track configuration, with minimum and maximum costs developed for each cell in the cost matrices. The minimum costs are based on maintenance standards geared to typical Class I freight railroad practice, such as where passenger trains currently operate on a freight railroad right of way, while the maximum costs reflect maintenance practices on existing high speed railroad track. This paper provides a description of the analytic models used to generate the costs, and the process by which those models were calibrated to actual cost data to develop costs for a wide range of traffic and track combinations. Sample application of the methodology to include several proposed mixed use corridors is also presented.
Management of Broken Rail Risk for High Speed Passenger Rail
Authors: Zarembski Allan M.
Published: November 2010

The issue of broken rail risk has been of major concern to railways worldwide, to include passenger and freight railways. Broken rail derailments on high speed passenger operations are of particular concern, as depicted by the consequences of the 2000 Hatfield derailment in the UK. Research studies have shown that the risk of broken rail derailments is directly related to the rate of rail defect development and the associated relationship between service defects and detected defects. This paper examines the relationship between rail defects and broken rail derailments together with techniques used to reduce the risk of these broken rail derailments. Specifically, the paper focuses on the relationship between all defects, service defects and derailments and examines the effect on improved inspection, either through improved inspection technology or improved inspection scheduling, on reducing rail service defects and associated derailments. The paper also examines the levels of broken rail risk that have been found on freight and passenger systems in North America and Europe and provides guidelines for the range of broken rail risk that has been found effective.
The Development of a Railway Safety Assessment Program in South Korea
Authors: Noh H. M. , Cho Y. O. , Wang J. B.
Published: November 2010

In this paper, a whole development process of a railway safety assessment program in South Korea is introduced. A railway safety assessment program is a web-based software program to examine safety documents automatically and to support railway safety assessor by providing checklists. The railway safety documents assessed in this program are safety management system (SMS) documents and engineering safety management (ESM) documents. The railway safety documents are examined automatically by software engines and results of the examination are provided to assessors. The program also provides the assessors with document checklists. The railway safety assessment program will become a beneficial web-based program for examining and investigating railway safety documents in South Korea.
Planning Capacity Improvements in the Chicago – Milwaukee – Madison Rail Corridor Using the Rail Traffic Controller (RTC) Rail Operations Simulation Model
Authors: Tobias Alan , House David , Wade Randy
Published: November 2010

The Wisconsin Department of Transportation (WisDOT) contracted HNTB Corporation (HNTB) to utilize the Rail Traffic Controller™ (RTC™) computer simulation software developed by Berkeley Simulation Software to analyze the rail capacity requirements for high speed (110 mph maximum) Chicago to Milwaukee to Madison passenger rail service. The purpose of this study was to determine whether sufficient capacity exists in the corridor to accommodate the projected growth in intercity passenger rail service as well as growth in freight and commuter rail service. Where capacity constraints were identified, the model was also used to evaluate the benefits of proposed infrastructure improvements. HNTB and WisDOT worked with Illinois DOT, the Canadian Pacific Railway, Metra and Amtrak to identify and test rail improvements that will provide sufficient capacity for projected future high speed, commuter and freight rail services in the corridor. The modeling results are shown through string lines and tables comparing the impacts of each case on the performance of each type of train. Metrics used include: • Average speeds. • Delay minutes per 100 miles. • On Time Performance (for passenger trains). RTC is a very useful tool for the simulation of current and proposed rail operations. It has helped identify bottlenecks and analyze the effectiveness of proposed improvements. The model results from this study are a critical component in WisDOT’s negotiations with CP over the extent and location of capacity improvements for high speed operations. The RTC model output also supported WisDOT’s application for federal stimulus funding for the corridor improvements.
Cross Wind Protection Systems for High Speed Railway Lines
Authors: Alvarez-Legazpi Paula , Vargas-Mun˜oz Marta , Marti´nez-Acevedo Jose´ Conrado , Botella-Malago´n Joaqui´n , Rodri´guez-Ferna´ndez Manuel
Published: November 2010

Higher operating rail speeds and lighter rolling stock means that cross wind, a factor that had not been considered for railway operations until recent times, has acquired vital importance in keeping adequate safety levels for railway transport of passengers. The overturn risk for a train circulating on a high speed line is determined by three key issues: • TRAIN: its aerodynamic and dynamic characteristics. • LINE: radius, azimuth, type of infrastructure, etc. • WIND: speed and angle with the train: – Wind statistics at the cross wind detection stations. – Wind models with spatial extrapolation for estimating average and actual wind on each section of the line. – Temporal forecast models at the cross wind detection stations. The combination of a certain rail line and a specific vehicle allows the determination of the criticality of each site. Once the authoritative safety target has been defined, according to this overturn risk, the adequate operating procedures must be defined. There are three possible types of protection systems: • Passive protection: protection walls or wind screens. • Active protection: short term (minutes) wind alert systems that impose restrictions to train speed when strong cross wind conditions are predicted. • Special procedures to regulate railway traffic under critical wind conditions. This paper presented hereby describes the studies to determine the susceptible sections to be protected, focus afterwards, specifically on active protection systems themselves, and main actions for its implementation.
Design Considerations in the Development of a North American High Speed Turnout
Authors: Abbott Brian C. , Lee Tom , Click Gary , Mattson Steve , Ouelette Ken W.
Published: November 2010

North American turnout and special trackwork design has evolved in an operating environment in which axle loads have increased significantly but operating speeds have remained modest. Consequently, while trackwork components have become much more robust, turnout geometries and overall system design has remained essentially static for many decades. Implementation of high speed rail (“HSR”) in North America will necessitate a radically different approach to turnout engineering. While there is much to be learned from European and Asian experience with high speed, it is anticipated that vehicle designs and mixed freight access will result in much greater axle loads. The combination of operating speed and loading will present unique challenges. Critical design elements for North America’s new generation of HSR turnouts will include: a) Compound geometries to optimize ride quality and safety while keeping overall lengths within manageable limits. b) Fastening and horizontal support systems to withstand high dynamic lateral loads. c) Dampening systems to attenuate high frequency vibration. d) Detailing such as rail seat canting and kinematic gauge optimization to enhance ride quality and increase component life. e) High modulus vertical support systems. f) Drive and locking systems specifically tailored to long HSR layouts. Regulations governing the layout and maintenance tolerances of North American turnouts will also have to be re-examined with the advent of high speed rail. Complex geometries and rapid transient loading will render the conventional approach of limiting speeds based on calculated imbalance ineffective. Accurate and rational assessment of operating safety will demand the application of dynamic numeric modeling to the entire vehicle / turnout system.
Study on Optimization of Train Line Planning for High Speed Rail Corridor Based on Analyzing Importance of Nodes
Authors: Niu Yong-Tao , Han Bao-Ming , Liu Min , Zhu Qing-Lan
Published: November 2010

In order to meet the demand of passengers for travelling and make their travelling more convenient, the railway operator must ascertain the operational train number, section, classes, stop stations and appropriate departure and arrival stations for passenger trains. The nodes of railway passenger transport are the generation and attraction points of passenger flow in the railway transport network. Starting from the analysis of the economic and social attributes as well as railway resource allocation of the Passenger Dedicated Railway Line (PDRL) covered nodes, this paper introduces the concept of the importance of nodes. On the basis of analytical hierarchy process (AHP), the paper studies the quantitative index of the nodes transport distribution capacity in the PDRL network and calculates the evaluation indexes of importance of those city nodes. Thus, in the light of the assessment results, the paper sets up the three-level hierarchy in the importance of city nodes covered by the PDRL. Based on that, the paper proposes that the first-level nodes serve as the departure and arrival stations, the second-level nodes adopt the fluid and alternate stop stations, and the tertiary-level nodes take the form of “all-stop” for low-class trains so as to build a multi-objective programming model for the PDRL train line planning. With the lingo 8.0 program, the train line planning optimizes the calculation of stop stations. This method has been applied in the PDRL train line planning of Wuhan-GuangZhou High-Speed Railway Line and proved to be effective in reducing the complexity of the train line planning problem according to different modes of passenger flow.
Heavy Haul Railway Electrification: Experiences and Prospects
Authors: van der Meulen Dave
Published: November 2010

The paper sets out to consolidate relevant learning from South Africa’s two electric heavy haul operations, and relate it to practices in two significant heavy hauling countries, the US as font of heavy haul, and China that has established a significant presence in heavy haul. In comparing the present dominant diesel heavy haul with electric heavy haul, it is evident that the latter can offer sustainability through open system interaction with its environment. However, electric heavy haul solutions are still divergent, contrary to what one would expect in a globalized industry. Reviewing prospects for consideration leads to a main conclusion that future heavy haul electrification should rest on an open system approach within a smart total energy management paradigm.
Optimizing Wheel/Rail Performance on High Speed, Mixed Traffic Corridors
Authors: Magel Eric E. , Helfrich Brian , Tajaddini Ali
Published: November 2010

Between 2001 and 2009, a series of field, laboratory and theoretical studies were conducted with FRA sponsorship to better understand the wheel/rail interaction on Amtrak’s multi-user Northeast Corridor. The development of a new wheel profile, optimized rail profiles, friction management practices and a grinding strategy were key aspects of the program. The experience gathered over an eight year period, including many lessons learned, has been collected and provides a template for how optimization of the wheel/rail interaction can be undertaken on high speed, shared use railway corridors.
Rail Wear Simulation and Validation
Authors: Shu Xinggao , Dembosky Mark , Urban Curtis , Wilson Nicholas
Published: November 2010

Transportation Technology Center, Inc. (TTCI), a wholly owned subsidiary of the Association of American Railroads (AAR), has developed an iterative rail wear prediction model in the NUCARS® vehicle/track interaction multibody simulation program through internal research and development efforts and with funding from Network Rail (NR) in the UK. The rail wear model was built upon the NUCARS® penetration model1 to take advantage of the wheel/rail (W/R) contact calculation methodology for conformal W/R profiles. In addition to the advantages of NUCARS vehicle and track modeling capabilities, it modifies the rail profile online based on the Wear Indices (Tγ) and penetrated W/R profile shapes in the multipoint contact patches, and automatically updates the rail profile for the next run. The penetrated wheel profile segments or “wheel footprints” are blended into the modified rail profile. The worn rail shape eventually resembles the wheel shapes in the wheel database, and the wear process results in conformal W/R profile shapes. Rail wear prediction was validated using rail wear test results based on 515 million gross tons (MGT) of heavy axle load (39-ton (35-tonne) axle loads) freight traffic accumulated from 2003 to 2007 at the Facility for Accelerated Service Testing (FAST) on the nonground test zone (Section 25, 6-degree (291-meter (m)) curve with 5 inches (127 millimeter (mm)) superelevation). A wheel database, consisting of 50 measured new, mildly worn and heavily worn FAST train wheel profiles, was used to reflect the wheel shape effects during the wear process. This model has been used to predict rail relative wear trends of ground rail profiles for NR.2,3,4 A quantified W/R gap loss function has been implemented in NR’s Track-Ex© program5 for prioritizing rail grinding.
Nondestructive Inspection Methods for Railroad Castings
Authors: Carter Daniel , Gonzales Kari
Published: November 2010

Transportation Technology Center, Inc. (TTCI) has investigated various nondestructive inspection (NDI) methods to determine if they are capable of reliably inspecting side frames, bolsters, knuckles, and couplers. The NDI methods used for this investigation include dry and wet (fluorescent) magnetic particle, liquid penetrant, alcohol wipe, visual, ultrasonic (pulse-echo and phased array), and radiography. Inspection results from all methods were used to determine which methods produced repeatable results. From the initial inspection analysis, TTCI engineers determined that the magnetic particle inspection method is the most capable for detecting defects in railroad castings. Further investigation of the magnetic particle technique was completed to develop reliable inspection methods for use on bolsters, side frames, knuckles, and couplers. Each of the inspection techniques have been used for inspections in the field. Using the results of the field tests, procedures were developed by TTCI and submitted to the Association of American Railroads’ (AAR) Coupling Systems and Truck Castings Committee for review and implementation. The inspection procedures can be used by manufacturers, railroads, and car repair shops. Limitations of the inspection procedures include the amount of time necessary to perform the inspection and the reliability of detecting certain types of defects below the surface of the casting. Although these limitations exist, the procedures developed by TTCI are expected to improve the quality of in-service castings and reduce the number of train partings and derailments due to broken or cracked components.
Comprehensive Inspection Technologies of High-Speed Railways
Authors: Hou Weixing
Published: November 2010

This paper introduces the applied comprehensive inspection technologies that satisfy the demand of safety and high operation efficiency on new-constructed PDLs and speed-up existing lines in China, including the improved static and dynamic supervision system, advanced comprehensive inspection train, accurate specified inspection devices, scientific data analysis and evaluation method and current regulations of inspection management. The paper also introduces the application status of the comprehensive inspection technologies in China and its development expectation.
Influence of Embankments With Parapets on the Cross-Wind Turbulence Intensity at the Contact Wire of Railway Overheads
Authors: Avila-Sanchez Sergio , Lopez-Garcia Oscar , Meseguer Jose
Published: November 2010

Winds as an environmental factor can cause significant difficulties for the railway system operation. The railway overhead has been particularly vulnerable to cross-winds related problems, such as development of undamped oscillations due to galloping phenomenon. The installation of windbreaks to decrease the aerodynamic loads on the train can affect the loads on railway overheads triggering cable galloping. One essential parameter to indicate the influence of the parapet wake on the catenary contact wire is the turbulence intensity. In this paper the results of an experimental analysis of the turbulence intensity due to the presence of parapets carried out in a wind tunnel are reported. Embankments equipped with different parapets have been tested and turbulence intensity has been measured at both contact wire locations, windward and leeward. The relative influence of the parapets is measured through a reduced turbulence intensity, defined as the ratio between the turbulence intensity measured with parapet and the turbulence intensity in the case without any parapet on the embankment. In general the reduced turbulence intensity increases as the height of the parapet increases.
Polyurethane Coating of Railroad Ballast Aggregate for Improved Performance
Authors: Dersch Marcus S. , Tutumluer Erol , Peeler Calvin T. , Bower David K.
Published: November 2010

This paper presents preliminary findings of a new technology currently being tested in a research project at the University of Illinois. The effectiveness of elastomer polyurethane coating of ballast is evaluated for its ability to reduce aggregate breakage and resulting ballast fouling. Railroad ballast degradation and fouling related to aggregate breakdown under heavy axle loads, poor drainage, mud pumping, and water/ballast pockets are among the most commonly encountered track substructure (ballast, subballast, and subgrade soil) problems. The structural integrity of seriously fouled ballast can be compromised leading to track instability and ultimately, train derailments. Because of this serious consequence, costly ballast maintenance activities, such as undercutting, tamping, and shoulder cleaning, are routinely performed by railroads especially on tracks serving the heavy axle load unit trains. In the research project, clean AREMA No.4 aggregates along with the polyurethane coated particles were subjected to realistic field loading conditions in a large shear box test apparatus used for strength testing of ballast at full gradation. The urethane coated ballast was allowed to set for 1, 3, 7, and 14 days prior to subjecting the samples up to 10 shear passes. Shear and normal stress data were gathered during testing; and the fines generated by all tested samples were collected and analyzed. Early findings show a major increase in the shear strength gained with the polyurethane coating, a decrease in the breakdown of the coated ballast, and a decrease in particle reorientation which could lead to a reduction in ballast settlement.
Improved Performance Track Components for Heavy Axle Loads and High Speed Rail
Authors: Davis David D. , LoPresti Joseph , Kalay Semih
Published: November 2010

North American railways have experienced significant traffic growth over the past 20 years to the point where many lines are at or near capacity. While the current worldwide recession has eased capacity constraints momentarily, the long-term trends are for continued traffic growth. Faced with the prospects of perhaps doubling freight traffic demand in the next 20 years and adding significant passenger traffic, the railroads are developing cost effective ways to increase capacity. Besides constructing additional tracks, improving the performance (i.e., safety, reliability, and service lives) of key track components is expected. Both heavy axle loads (HAL) and high speed rail (HSR) passenger traffic require high quality, durable track. The paper will describe recent work done to improve the dynamic performance and durability of these track components: • Special trackwork. • Rail joints. • Crossties. • Track transitions. For example, turnouts are being developed that can accommodate freight shippers served from mainline track that also carry high speed traffic. These continuous mainline rail switches and frogs allow slow speed diverging operations that will not affect mainline track performance. The paper will also discuss further heavy haul infrastructure research and development needs.
Track Substructure Design Methodology and Data
Authors: Sussmann Theodore R. , Hyslip James P.
Published: November 2010

Track substructure design is an often overlooked step in the design of railroad track. The lack of consideration for the substructure when designing track results in greater maintenance demands due to inadequate track substructure performance. Railway track is a stable structure with a progressive failure process that allows track engineers to manage the degradation of the track through maintenance. However, increasing demands for track availability from high traffic volumes require that track maintenance be minimized while ensuring safety. Additionally, developing high speed rail and intercity passenger rail on existing corridors necessitates higher levels of substructure performance due to tighter track roughness tolerances. Reduction in maintenance needs can be achieved by ensuring that new construction and rehabilitation projects be designed to provide a stable track structure throughout the design life. Lack of readily available data for substructure materials is a drawback to the use of track design methods. This paper provides a summary of several available substructure track design methods along with the required data for design. The track design data is related to track measurements that could be used to determine much of the information necessary for design of track rehabilitation. Track load-deflection data could be used to develop much of the needed design data while ground penetrating radar could support delineation of similar track segments. Benefits of track structure design include knowledge of expected life, reduced maintenance, material properties for quality control, and development of material properties that could permit application of performance based contract specifications.
Motion-Based Energy Harvesting Devices for Railroad Applications
Authors: Nagode C. , Ahmadian M. , Taheri S.
Published: November 2010

As the story goes, a wise railroad man once declared: Power is the king! Although he was referring to the motive power that we need to move freight, the same could be said about the availability of electrical power on railcars. This is mainly due to the fact that the onboard applications of many smart devices that can add to the efficiency of rail operation are hindered by the lack of availability of electrical power. In this paper, innovative solutions to provide a distributed source of electrical power for railroad onboard applications are presented. In a suspension of a railcar, mechanical energy is dissipated in dampers or wedges and, therefore, wasted in heat. Meant to be placed inside the coil springs of the suspension, the proposed vibration-based electromechanical systems are designed to harvest part of that wasted energy and turn it into useful electrical power. The energy produced is then conditioned and stored in commonly available batteries. The possibility of realizing the mechanical-to-electrical power conversion without any prior transformation of the mechanical input is first investigated. This aims to avoid inherent losses induced in such processes. The prototypes use an arrangement of magnets that moves linearly with the suspension inside one or several coils. The variable magnetic field thus created generates a voltage. The prototypes prove that it is possible to use a translational generator to provide enough power for recharging batteries under conditions commonly experienced in railcar operation. The second generation of prototypes investigates the idea of transforming the input translation from the suspension into rotation and then using a rotary generator. The advantage of developing such a concept is the possibility of including a gearbox to increase the generator speed of rotation. Maintaining high shaft speed is the key to harvest more power and reach higher efficiencies. The output power is improved even more by adding a mechanism that rotates the generator shaft in the same direction independently of how the suspension is moving (jounce or rebound). Both designs prove they can recharge batteries under commonly experienced conditions. But although the linear generator shows some limitations in terms of power (up to a few watts RMS), the rotary generator design demonstrates significantly higher efficiency and greater output power (40Watts RMS with a sine wave input of ±0.75in at 1Hz). The amount of generated power can be augmented by increasing the amplitude and/or the frequency of the input, customizing the generator, and bringing new improvements to the mechanical part of the system.
Modeling of the Effect of Embankment Dimensions on the Mechanical Behavior of Railway Track
Authors: Kalliainen Antti , Kolisoja Pauli , Nurmikolu Antti
Published: November 2010

In the Northern areas the total thickness of structural layers in railway embankments is primarily governed by the design against harmful effect of seasonal frost. Because practically no frost heave can be allowed to take place on railway tracks with normal speed passenger traffic, the embankment must typically be built up to two or even two and a half meters thick. Meantime, the embankments have typically fairly steep slopes, for instance in Finland track embankments are normally built using a slope ratio of 1:1.5. Introduction of higher allowable axle loads and traffic speeds is, however, exposing the embankments structures to continuously increasing intensity of repeated loading which is also increasing the rate of permanent deformations accumulating into the embankment structure. In practical terms the embankment is widening as it deforms and the respective movements of the track must be compensated by more frequent maintenance actions. The most straightforward measures to increase the internal stability of a railway embankment are to make the embankment wider and/or to reduce the slope steepness of the embankment. Both of these actions mean, however, larger space requirement for the railway track and, above all, extensive increase in the use of high-quality non-frost-susceptible aggregate materials in connection with the embankment construction or renovation. Therefore, taking into account both the construction time costs on one hand and the maintenance costs of the track on the other hand, optimisation of the embankment dimensions and shape is an important issue regarding the life cycle costs of a railway line. In a research project going on at the Laboratory of Earth and Foundation Structures of the Tampere University of Technology the above mentioned problem is being studied by in-situ monitoring of a full scale railway track embankment having sections that are shaped in different embankment widths and slope angles. The long term deformations of the embankment have been monitored for about three years in addition to which also the short term responses of the embankment structure have been measured while trains are passing over the monitoring sections. In addition, model scale (1:4) test structures with different embankment widths and slope angles have been tested in laboratory using a loading system consisting of five hydraulic actuators operating consecutively so as to simulate the loading effect of a moving train. The results obtained so far indicate clearly that it is not only the embankment width and slope angle that are decisive concerning the permanent deformation behaviour of the railway embankment, but also the subgrade stiffness plays an important role in the overall performance of the embankment structure.
Development of a Robust Miniature Loop Heat Pipe for High Power Chip Cooling
Authors: Li Ji , Wang Daming , Peterson G. P.
Published: November 2010

In this work, systematic experimental and theoretical investigations were carried out on a copper-water compact loop heat pipe with a flat square evaporator having a bottom area of 30mm×30mm. Wick structure inside the evaporator was made of microscale copper powder with carefully designed vapor removal channels sintered directly on the substrate. In addition, the design and fabrication of a 120mm air-cooled condenser was given adequate consideration. From the experimental tests, it is found that such a small loop heat pipe can manage a heat load of more than 600W, and no dry-out occurs. In the favorable vertical configuration, with an air velocity of 2.8m/s, this compact loop heat pipe has a thermal resistance as low as 0.042 0C/W, with a corresponding evaporator thermal resistance as low as 0.018 0C/W.
Liquid-Vapor Oscillating Flow and Heat Transfer in a U-Shaped Minichannel With Internal Wick Structure
Authors: Xu Jiajun , Zhang Yuwen , Ma H. B.
Published: November 2010

Liquid-vapor oscillating flow and heat transfer in a vertically placed oscillating heat pipe (OHP) with a sintered particle wick structure inside are analyzed in this paper. The evaporation and condensation heat transfer coefficients are obtained by solving the microfilm evaporation and condensation on the sintered particles. The sensible heat transfer between the liquid slug and the channel wall are obtained by analytical solution or empirical correlations, depending on whether the liquid flow is laminar or turbulent. The effects of the maximum evaporation and condensation angles on the oscillatory flow, as well as sensible and latent heat transfer are analyzed.
Modeling Heat and Mass Transfer Correlations for Flow Through Micro Channels in Monolith Honeycomb Catalytic Combustor
Authors: Yin Juan , Weng Yi-wu
Published: November 2010

This paper investigated performance characteristics analysis of catalytic combustion by utilizing 1-D models incorporated heat and mass transfer correlations. The 1-D numerical results were compared with 2-D models studies and experimental data. The performance characteristics were mainly the effects of operating conditions on methane conversion rate. The comparable analysis confirmed that 1-D model can success in predicting performance of catalytic combustion when empiric inter-phase heat and mass transfer correlations are used and appropriate operating conditions are chosen.
The Influence of Super Gravity on Flow and Heat Transfer Characteristics in Straight Microchannel
Authors: Xi Youmin , Yu Jianzu , Xie Yongqi , Gao Hongxia
Published: November 2010

High maneuverability has been a major performance index of modern military combat flight. Thus, the avionics installed on the flight will frequently suffer the effects of acceleration. The flow and heat dissipation performance of avionics heat sink will be affected by the super gravity environment. In order to clarify the effects of acceleration, simulative accelerating experiments of flow and heat transfer performance in straight microchannel with rectangular cross section have been conducted. A test piece made of copper is machined. FC-72 is taken as coolant. Simulative accelerating equipment is set up, on which the test piece is installed. Several different acceleration conditions are applied in the experiment. The resulting centripetal acceleration ranged from 0g to 15g. Tests are conducted by varying heat load, flow flux, and microchannel orientation relative to the direction of the accelerating force. In this study, new experimental data is presented. The flow and heat transfer performance in straight microchannel under the effects of acceleration is analyzed. The result shows that the directions and amplitudes of the acceleration have great effects on flow and heat transfer performance in the channel.
Heat Conduction of a Porous Material
Authors: Miyazaki Koji
Published: November 2010

In this study we introduce our numerical and experimental works for the thermal conductivity reduction by using a porous material. Recently thermal conductivity reduction has been one of the key technologies to enhance the figure of merit (ZT) of a thermoelectric material. We carry out numerical calculations of heat conduction in porous materials, such as, phonon Boltzmann transport (BTE), molecular dynamics simulations (MD), in order to investigate the mechanism of the thermal conductivity reduction of a porous material. In the BTE, we applied the periodic boundary conditions with constant heat flux to calculate the effective thermal conductivity of porous materials. In the MD simulation, we calculated phonon properties of Si by using the Stillinger-Weber potential at constant temperature with periodic boundary conditions in the x, y and z directions. Phonon dispersion curves of single crystal of Si calculated from MD results by time-space 2D FFT are agreed well with reference data. Moreover, the effects of nano-porous structures on both the phonon group velocity and the phonon density of states (DOS) are discussed. At last, we made a porous p-type Bi2Te3 by nano-particles prepared by a beads milling method. The thermal conductivity is one-fifth of that of a bulk material as well as keeping the same Seebeck coefficient as the bulk value. However electrical conductivity was much reduced, and the ZT was only 0.048.