bluuebunny/crossref_metadata_2025 huggingface dataset:
Bellini, bronze and bombards: Sultan Mehmed II's requests reconsidered
Authors: Cevizli Antonia Gatward
Published: February 2014

Gentile Bellini's portrait of the Ottoman sultan Mehmed II, painted in 1480 during the artist's stay in the Ottoman capital, has become emblematic of cultural exchange between Venice and the Ottomans. However, documentary evidence suggests that the sultan was more interested in obtaining bronze founders than painters. A re‐consideration of the documents of the Venetian Senate from 1479–1480 will alter the perspective from which this episode is usually viewed, giving Bellini a less central role and indicating that the contemporary mission of the bronze founder Bartolomeo Bellano was of no less importance. Mehmed's requests for bronze founders – made simultaneously to Venice and Florence – have been interpreted as a sign of Mehmed's enthusiasm for portrait medals. This explanation will be questioned and it will be argued that the sultan's interest in bronze founders extended beyond their artistic production to their knowledge of cannon technology, shedding light on Venice's refusal to send a second founder.
Corporate Social Responsibility and International Competition: A Welfare Analysis
Authors: Chang Yang‐Ming , Chen Hung‐Yi , Wang Leonard F. S. , Wu Shih‐Jye
Published: February 2014

This paper examines the welfare implications of corporate social responsibility (CSR) in international markets under imperfect competition. Based on a stylized model of an import‐competing duopolistic market, we show the feasibility of moving toward tariff reductions when both domestic and foreign firms launch CSR initiatives in that their payoffs include not only individual profits, but also the benefits of consumers. For the case where the foreign exporter unilaterally adopts the consumer‐oriented CSR as a strategy, there is a rent‐shifting effect because the foreign firm's payoff increases whereas the domestic firm's profit decreases. In response, the importing country's government raises its tariff on the foreign product. If, instead, the domestic firm adopts the CSR strategy unilaterally, the rent‐shifting effect disappears and both the competing firms’ payoffs increase. We further identify the conditions under which the CSR initiatives of the firms constitute the dominant strategy, leading to a Pareto efficient outcome at which the firms’ payoffs, consumer surplus, and social welfare are at their maximum levels.
Feasibility of a Web‐based Gatekeeper Training: Implications for Suicide Prevention
Authors: Lancaster Paige G. , Moore J. Taylor , Putter Stefanie E. , Chen Peter Y. , Cigularov Konstantin P. , Baker Aaron , Quinnett Paul
Published: February 2014

Web‐based training programs have advantages such as increased scheduling flexibility and decreased training costs. Yet the feasibility of applying them to injury prevention programs such as suicide prevention gatekeeper training has not been empirically verified. Two studies were conducted to assess the feasibility and effectiveness of a web‐based version of the Question, Persuade, and Refer (QPR) gatekeeper training program. Results of Study 1 revealed that participants in a web‐based training demonstrated significant gains in knowledge of suicide prevention, self‐efficacy for suicide prevention, and behavioral intentions to engage in suicide prevention, as compared to those in a control group. Results of Study 2 further showed that the web‐based training may be as effective as the face‐to‐face QPR training across pre‐ (T1) and post training (T2); however, knowledge, self‐efficacy, and behavioral intentions in both groups generally declined from T2 to 6‐months after the training. Overall, these results provide initial evidence to support the feasibility of adopting web‐based media to deliver gatekeeper training. Moreover, the present findings suggest the need to understand how to maintain gatekeepers’ knowledge, confidence, motivation, and skills after training.
Deep functional redundancy between FAMA and FOUR LIPS in stomatal development
Authors: Lee EunKyoung , Lucas Jessica Regan , Sack Fred David
Published: February 2014

Functional redundancy arises between gene paralogs as well as non‐homologous genes that play a common role at a shared node. The bHLH transcription factor FAMA, along with the paralogous MYB genes, FOUR LIPS (FLP) and MYB88 all ensure that Arabidopsis stomata contain just two guard cells (GCs) by enforcing a single symmetric precursor cell division before stomatal maturity. Consistent with this function, FLP and FAMA exhibit the same expression pattern in which both translational GFP fusions emit fluorescence just before and after symmetric division; however, FAMA but not FLP is required to confer GC fate. Strikingly, swapping the genes and promoters of the FLP and FAMA genes results in the reciprocal complementation of respective loss‐of‐function mutants. Thus, an FLP transgene can restore GC fate to a fama mutant background. FAMA, FLP and the FLP paralog MYB88 were previously shown to influence higher order functions in stomatal development, including maintaining and stabilizing stomatal fate. Here we show that these overlapping functions are likely to also involve interactions between FLP and FAMA with the RETINOBLASTOMA‐RELATED (RBR) protein.
Sliding Mode Observer and State-Machine-Based Fault Diagnosis With Application in a Vehicle Chassis Steering System
Authors: Zhang Xian , Pisu Pierluigi
Published: February 2014

A novel fault detection and identification (FDI) scheme based on sliding mode observer (SMO) residual generator and state machine residual evaluator is presented in this paper. The FDI scheme is applied to actuator and sensor faults in a vehicle chassis steering system described by a nonlinear bicycle model with three degrees of freedom. Primary residual is generated by an expanded SMO designed for linear time varying (LTV) systems. To cope with the multiple faults isolation problem, the state machine records and utilizes the previous fault information to determine the current fault state. Simulation results show that multiple fault detection and isolation can be successfully achieved by the proposed SMO and state-machine-based FDI scheme.
Efficient Computation of Separation-Compliant Speed Advisories for Air Traffic Arriving in Terminal Airspace
Authors: Sadovsky Alexander V. , Davis Damek , Isaacson Douglas R.
Published: February 2014

A class of problems in air traffic management (ATM) asks for a scheduling algorithm that supplies the air traffic services authority not only with a schedule of arrivals and departures but also with speed advisories. Since advisories must be finite, a scheduling algorithm must ultimately produce a finite data set, hence must either start with a purely discrete model or involve a discretization of a continuous one. The former choice, often preferred for intuitive clarity, naturally leads to mixed-integer programs (MIPs), hindering proofs of correctness and computational cost bounds (crucial for real-time operations). In this paper, a hybrid control system is used to model air traffic scheduling, capturing both the discrete and continuous aspects. This framework is applied to a class of problems, called the fully routed nominal problem. We prove a number of geometric results on feasible schedules and use these results to formulate an algorithm that attempts to compute a collective speed advisory, effectively piecewise linear with finitely many vertices, and has computational cost polynomial in the number of aircraft. This work is a first step toward optimization and models refined with more realistic detail.
An Extended Second Order Polynomial Model for Hydraulic Fluid Density
Authors: Karjalainen J.-P. , Karjalainen R. , Huhtala K.
Published: February 2014

In this paper, a second order polynomial model for predicting the pressure-temperature behaviour of the density of any hydraulic fluid is presented. The model is an extension of the previously published model by the same authors for more moderate operating temperatures. Nevertheless, for a user the extension will not add any more complexity to the model. Even at a wider operating range, the density model can still always be parameterized without any unknown variables, once the standard fluid characteristics are available.

It is shown that compared to the measured values the maximum modelling error is well within 1% at the studied pressure range of up to 1500 bar, and at the studied temperature ranges overall covering from +20 to +130°C, with all the studied fluids.

This study includes 10 highly different hydraulic fluids used in various fluid power applications as power transmission fluids or fuel oils. The studied fluids have a density range from 827 to 997.2 kg/m3, and an ISO VG range from 2.6 to 1187. Also the studied base fluids cover a wide range. Moreover, the studied fluids contain different additives or not even additives at all (crude oils). Neither the base fluid nor the additives will be discovered to affect the received modelling accuracy.
New Designs in Fuel Dispensing System to Reduce Water Hammer
Authors: Liu Y. J. , Wang Z. Y. , Huang Z. Y. , Lumkes J.
Published: February 2014

Dispensers are used for refueling vehicles at the service station. During the refueling process, the velocity of fluid changes rapidly in several working conditions, which results in a rapid pressure increasing or a water hammer effect occurring. Water hammer, often causes leakage or failure of dispensers, occurs due to pump start-up and shut-down, valves opening or closing during the refueling process. This paper experimentally characterized and theoretically calculated the impact of water hammer on the dispensers at the service station. New designs of nozzle structure and new flow-rate control modes are made to reduce the water hammer in the fuel dispensing system. Eventually, all the water hammers are reduced significantly during the refueling process under the new design modes.
Determining Water Content at Saturation for Three Common Wind Turbine Gearbox Oils: Mobilgear SHC XMP 320, AMSOIL EP Gear Lube ISO-320 and Castrol Optigear A320
Authors: Whitten Matthew S. , Stelson Kim A.
Published: February 2014

To meet America’s growing energy demand, wind turbines will need to become larger and more cost effective [1]. However, estimates show that the average wind farm energy output is 10 percent less than predicted and that half of this short fall is due to gearbox downtime [2]. Increasing service life of the gearbox begins with monitoring the oil and controlling contamination by both particles and water. When online relative humidity monitoring is not available, oil samples from the gearbox need to be analyzed for quality and remaining service life. Field samples sent to a lab for testing often report water content as parts per million (ppm). Because the gearbox oil should be dried or replaced before the relative humidity reaches 100 percent (saturation limit), a relationship between ppm and the oil’s saturation limit needs to be established. The present research characterizes this relationship using an environmental chamber to simulate operating conditions and Karl Fischer titration to measure the water content. The resulting plots are of water content (ppm) at saturation versus temperature for three common wind turbine gearbox oils: Mobilgear SHC XMP 320, AMSOIL EP Gear Lube ISO-320 and Castrol Optigear A320.
A Basic Study on the Response Dynamics of Pulse-Frequency Controlled Digital Hydraulic Drives
Authors: Gradl Christoph , Scheidl Rudolf
Published: February 2014

Various control strategies in digital hydraulics have been proposed and studied so far. In hydraulic switching control Pulse Width Modulation (PWM) of one or two switching valves was mostly considered. This paper deals with Pulse Frequency Control (PFC) which — opposite to PWM — uses the pulse repeating frequency and not the pulse width as control input. PFC may be to be preferred if the hydraulic switching device can realize a very particular pulse in a quite favorable way.

This paper studies the influences of the flow rate pulse shapes and of the pulse frequency on the overall system dynamics. Based on a dimensionless mathematical model of a simple linear hydraulic drive and on elementary performance requirements (e.g. overshooting and pressure pulsations) dimensioning rules are derived. In addition to a repeated pulsing single or just a few pulses are investigated. It turns out that particular single or twin pulses can realize stepping motions of the drive without subsequent pulsations. In this way a hydraulic stepping drive can be realized. In case of repeated pulsing, high pulsing frequencies, in particular frequencies well above the natural frequency of the drive system, reduce oscillations considerably. Such frequencies may be realized either by one high frequency pulse device or by several pulse devices which are arranged in parallel and are operated in a phase shifted mode.
MEMS Sensor Network Based Anti-Sway Control System for Articulated Hydraulic Crane
Authors: Honkakorpi Janne , Vihonen Juho , Mattila Jouni
Published: February 2014

Hydraulic articulated multi-joint crane systems are widely used for the transportation of heavy loads. High productivity requires a short cargo transportation time which can lead to undesirable oscillations during crane load acceleration and deceleration. Typically it is the task of a crane operator to suppress the load swing, but with ever-increasing demand for faster operation the need for supporting control systems is evident. For overhead gantry cranes such assisting control systems can be considered as state of the art. However, for more complex articulated multi-link cranes only a few applicable control concepts have been proposed. Load swing angle and angular velocity measurement, or corresponding state observer based estimation, has been seen as a main problem in the realization of such assisting control systems. To tackle the problem, we present a novel suspended load anti-sway control system for heavy-duty articulated hydraulic cranes using solely low-cost linear MEMS accelerometers and angular rate gyroscopes embedded into easy-to-install sensor units. The proposed closed-loop anti-sway controller uses a network of embedded MEMS sensors for the crane motion state, suspended load inclination angle and angular velocity estimation. The control concept uses a semi-active approach where the desired load velocity is set by the crane operator via e.g. joystick input and the underlying load oscillation damping control system creates the desired crane tip velocity. Comparative results of anti-sway control are obtained using high resolution incremental encoder feedback for the articulated crane and suspended load motion states. Our experimental results verify effectiveness of the proposed anti-sway control system for articulated hydraulic cranes as well as applicability of the proposed MEMS sensor network for real-time closed-loop control of multi-body manipulators.
Fuzzy PID and Contour Tracking as Applied to Position Control of a Pneumatic Gantry Robot
Authors: Waldie James , Surgenor Brian , Dehghan Behrad
Published: February 2014

In previous work, the performance of PID plus an adaptive neural network compensator (ANNC) was compared with the performance of a novel fuzzy adaptive PID algorithm, as applied to position control of one axis of a pneumatic gantry robot. The fuzzy PID controller was found to be superior. In this paper, a simplified non-adaptive fuzzy algorithm was applied to the control of both axes of the robot. Individual step results are first shown to confirm the validity of the simplified fuzzy PID controller. The fuzzy controller is then applied to a sinuosoidal tracking problem with and without a fuzzy PD tracking algorithm. Initial results are considered to be very promising. Future work requires developing an adaptive version of the controller in order to demonstrate robustness relative to changing tracking frequencies and changing supply pressures.
Simulation Based Design and Optimization of Digital Pump/Motors
Authors: Merrill Kyle J. , Breidi Farid Y. , Lumkes John
Published: February 2014

Current state of the art variable displacement pump/motors have high efficiencies when operating at high displacements. However, as the displacement of the pump/motor is reduced, the efficiency significantly decreases. Digital pump/motors aim to increase the efficiency and range of operation of the fluid power system by minimizing leakages, friction losses and compressibility losses. It is based on the concept of actively controlling high speed on/off valves connected to each piston cylinder displacement chamber. This work involves the development of a coupled dynamic model of a digital hydraulic pump/motor that is crucial for understanding the design tradeoffs and operating characteristics of the digital pump/motor. This simulation model can be used to characterize and predict the efficiency, define the dynamic response and flow requirements of on/off valves required to provide significant improvements in efficiency and dynamic response over traditional pump/motors, and perform design optimization studies. The model can analyze different operating strategies (flow limiting and flow diverting) and characterize the effects on pump/motor efficiency and flow ripple. The simulation analysis shows that the sequential flow limiting strategy yields the lowest power loss in both pumping and motoring and that small variances in the valve response would cause a significant loss of power.
A Novel Fluid–Structure–Thermal Interaction Model for the Analysis of the Lateral Lubricating Gap Flow in External Gear Machines
Authors: Dhar Sujan , Vacca Andrea , Lettini Antonio
Published: February 2014

A novel Fluid-Structure-Thermal Interaction (FSTI) model for modeling of the lateral lubricating gaps between gears and lateral bushes in External Gear Machines (EGM) is presented in this study. Pressure compensated lateral bushes are key design elements for efficient operation of EGMs for high pressure hydraulic applications. The axial balance of these elements determines their actual position during operation, with significant implications on the effective sealing capabilities of the displacement chambers and on the losses from viscous friction.

The FSTI model presented in this paper is the first model of the lateral lubricating interface in EGMs capable of considering the heat transfer, thermal effects in the fluid film and solid components as well as thermo-elastic deformation of the solids. These capabilities, alongside a fluid flow solver and a stress/deformation solver for solid components due to pressure loads, enable prediction of the film thickness in the lateral gaps in EGMs considering thermo-elastohydrodynamic lubrication (TEHD) for the first time. In the present study the formulation of the novel FSTI model and detailed results are discussed with a particular focus on understanding the implications of thermal and TEHD effects.
Pneumatic Strain Energy Accumulators for Exhaust Gas Recycling
Authors: Cramer Daniel N. , Barth Eric J.
Published: February 2014

Pneumatic actuators used in devices that, by their function require light weight and small size such as orthotics, can benefit from the inclusion of accumulators to harness and recycle energy normally lost in exhausted gases. In order for an accumulator to provide benefits to these small systems, they must possess relatively high gravimetric and volumetric energy densities with adequately high efficiencies as compared to conventional accumulators, like traditional spring piston accumulators. Constructing accumulators that primarily use strain as the primary energy storage method can provide the energy storage capacities and efficiencies needed, as well as a better pressure-volume relationship than a fixed-volume accumulator. This paper outlines the behavior of an elastomeric strain accumulator constructed using natural rubber tubes as the material for an accumulator. Tube shaped accumulators fill to a preset maximum diameter, constrained by a rigid shroud so that the material’s yield strength is not approached and to control the manner in which the accumulator expands. Controlling the manner of expansion for the accumulator allows a relatively constant pressure to be used through the majority of the fill cycle. Natural rubber accumulators were experimentally evaluated and characterized for their energy storage efficiencies over a range of different parameters allowing basic design criteria to be created for use in building accumulators tailored to specific system requirements.
Co-Simulation Based Design and Experimental Validation of Control Strategies for Digital Fluid Power Systems
Authors: Pindera Maciej Z. , Sun Yuzhi , Malosse Jean-Jacques , Garcia Jose M.
Published: February 2014

This work presents and experimentally validates the use of co-simulations in the virtual prototyping of control strategies for a digital hydraulic system. Co-simulations allow analysis of complex systems by partitioning the latter into a collection of well defined, interacting sub-systems and components. This approach is well suited for analysis of digital hydraulics. The system under consideration is composed of four two way, two position, on-off solenoid poppet valves connected to a double rod hydraulic cylinder actuator. The control task is to schedule the opening and closing of the valves to provide precise control of the requested actuator position. The actuator and valve dynamics are modeled as lumped parameter systems given by first order Ordinary Differential Equations (ODEs). The equations are solved simultaneously using a computationally efficient Chebyshev expansion approach. All co-simulations took no more than 10 seconds of computational time to execute on a standard PC with an Intel Core i7 processor. The valve and piston dynamics are fully coupled through exchange of flowrate and pressure data between the appropriate components. Coupling and data exchange were performed using the co-simulation environment CoSIM, which allows connection of arbitrary number of components in arbitrary configurations. The valve actuation strategies were based on selected versions of Bang-Bang control. The most successful was able to keep the actuator displacement with practically no oscillations about the requested set point. Preliminary results show that excellent position control characteristics can be obtained to within 2–3 percent of experimental data.
Fault Detection of an Electrohydrostatic Actuator With the SVSF Time-Varying Boundary Layer Concept
Authors: Gadsden S. Andrew , Habibi Saeid R.
Published: February 2014

The electrohydrostatic actuator (EHA) is an efficient type of actuator commonly used in aerospace applications. It makes use of a closed hydraulic circuit, a number of control valves, an electric motor, and a fluid pump (usually a type of gear pump). The smooth variable structure filter (SVSF) is a relatively new estimation strategy based on sliding mode concepts formulated in a predictor-corrector fashion. The SVSF offers a number of advantages over other traditional estimation methods, including robust and stable estimates, and an additional performance metric. A fixed smoothing boundary layer was implemented in an effort to ensure stable estimates, and is defined based on the amount of uncertainties and noise present in the estimation process. Recent advances in SVSF theory include a time-varying smoothing boundary layer. This method, known as the SVSF-VBL, offers an optimal formulation of the SVSF as well as a method for detecting changes or faults in a system. This paper implements the SVSF-VBL in an effort to detect faults in an EHA. The results are compared with traditional Kalman filter-based methods.
Towards Direct Numerical Simulation of Compressible Orifice Flow
Authors: Manhartsgruber Bernhard
Published: February 2014

Simulation methods from simple lumped parameter approaches to complex computational fluid dynamics codes have become a widely used tool in the fluid power community. Certain tasks like the predicition of flow forces on the control spools in valves or the design of port plates in axial piston pumps are usually treated by the aid of numerical simulation. Like in many other cases, the underlying principle is the control of flow by orifices. The importance of orifice flow for hydraulic systems is reflected by the vast number of publications on various aspects of orifice flow in the fluid power literature. In lumped parameter simulations, the orifice equation giving the flow rate as a square root of the pressure drop is widely used even in transient cases where it is not clear whether the flow develops fast enough to justify the assumption of stationary flow. On the other end of the model complexity spectrum computational fluid dynamcis codes are used in the fluid power community. These very complex models require a high number of parameters for the tuning of turbulence models, wall models, and the like. The quality of the results heavily dependes on a good choice for these parameters. Additionally, the vast majority of turbulent flow simulations is done with the assumption of an incompressible fluid. Very often, the results from simulations deviate heavily from measurement results and only after parameter tuning a good match between model and simulation is achieved. This paper suggests the use of direct numerical simulations for simple and prototypical geometries in order to gain a better understanding for transient orifice flows lacking the fully developed flow assumed in traditional models.
An Experimental and Modeling Study Into Using Normal and ISO Cetane Fuel Blends as a Surrogate for a Hydro-Processed Renewable Diesel (HRD) Fuel
Authors: Cowart Jim , Raynes Michael , Hamilton Len , Luning Prak Dianne , Mehl Marco , Pitz William
Published: February 2014

A new Hydro-processed Renewable Diesel (HRD) fuel is comprised of both straight chain and branched alkane fuel components. In an effort to find a research surrogate for this fuel, single cylinder engine testing was performed with various blends of n-hexadecane (cetane) and isocetane in order to find a binary surrogate mixture with similar performance characteristics to that of the HRD. A blend of approximately two-thirds n-hexadecane with one-third isocetane showed the most similar behavior based on conventional combustion metrics. Companion combustion modeling was then pursued using a combined detailed chemical kinetic mechanism for both n-hexadecane and isocetane. These modeling results show both the importance of isocetane in lengthening ignition delay, as well as the overall importance of chemical ignition delay as the dominating effect in the overall ignition delay of these binary blend fuels.
Gas Turbine/Reciprocating Internal Combustion Engine Integrated System for Fuel-Flexible, High Efficiency and Low Emissions Power Generation
Authors: Rabovitser Joseph , Pratapas John M. , Kezerle James , Kasab John
Published: February 2014

This paper reviews the technical approach and reports on the results of ASPEN Plus® modeling of two patented approaches for integrating a gas turbine with reciprocating internal combustion engine for lower emissions and higher efficiency power generation. In one approach, a partial oxidation gas turbine (POGT) is located in the 1st stage, and the H2-rich fuel gas from POGT exhaust is cooled and fed as main fuel to the second stage, ICE. In this case, the ICE operates in lean combustion mode. In the second approach, an ICE operates in partial oxidation mode (POX) in the 1st stage. The exhaust from the POX-ICE (a low BTU fuel gas) is combusted to drive a conventional GT in the 2nd stage of the integrated system. In both versions, use of staged reheat combustion leads to predictions of higher efficiency and lower emissions compared to independently providing the same amount of fuel to separate GT and ICE where both are configured for lean combustion. The POGT and GT analyzed in the integrated systems are based upon building them from commercially available turbocharger components (turbo-compressor and turbo-expander).

Modeling results with assumptions predicting 50–52% LHV fuel to power system efficiency and supporting NOx < 9 ppm for gaseous fuels are presented for these GT-ICE integrated systems.
Assessment of Combustion Characteristics of Higher Alcohols in a Direct Injection Spark Ignition Engine
Authors: Lawyer Kristina , Wallner Thomas , Ickes Andrew , Miers Scott , Naber Jeffrey , Ertl David , Williamson Rodney
Published: February 2014

The U.S. Renewable Fuel Standard requires an increase in the production of ethanol and advanced biofuels up to 36 billion gallons by 2022. Ethanol will be limited to 15 billion gallons, which leaves 21 billion gallons to come from other sources. Due to its high octane number, renewable character, and minimal toxicity, ethanol was believed to be one of the most favorable alternative fuels to displace gasoline in spark ignition engines.

Replacing gasoline with ethanol results in a substantial reduction in vehicle range, and high ethanol content blends can cause material compatibility issues and require adaptive engine calibrations. In addition, ethanol is fully miscible in water which requires blending at distribution sites instead of the refinery. Higher carbon number alcohols, on the other hand, have a higher energy density and lower affinity for water than ethanol, which could mitigate some of the above mentioned issues. However, little information is available on the combustion characteristics of a majority of the longer-chain alcohols.

This study evaluates the combustion properties of higher carbon number alcohols, ranging from ethanol (C2) to hexanol (C6) in a direct-injection, spark-ignition engine. Test fuels are created by splash blending alcohols at a volumetric concentration of 50% with a blendstock for oxygenate blending. Combustion characteristics are evaluated by comparing overall efficiencies as well as heat release characteristics and emissions for a set of representative steady-state operating points. Results suggest that combustion properties of blends of alcohols with carbon numbers from two to six are similar to those of the reference fuel at low and medium engine loads. Properties of blends of alcohols with carbon numbers from two to four are similar to those of the reference fuel even at high loads. However, due to their reduced knock resistance, the suitability of longer chain alcohols, specifically C5 and longer, as blending agents at increased levels is questionable.
Experimental Investigation of Spray and Combustion Characteristics of Soybean Biodiesel in a Constant-Volume Combustion Chamber: The Effects of Fuel and Ambient Gas Temperature
Authors: Wu Yifeng , Huang Ronghua , Lee Chia-fon F.
Published: February 2014

Effects of fuel and ambient gas temperature on the spray and combustion characteristics of soybean biodiesel were studied in a constant-volume combustion chamber. Four different fuels or fuel blends including B0, B20, B50 and B100 were investigated experimentally. The soot mass data were obtained via a new technique called forward illumination light extinction (FILE). The ambient gas temperature was varied from 700 K to 1200 K. To simulate the engine operating conditions, the ambient oxygen concentration and its density were kept at 21 % and 15 kg/m3, respectively.

A higher peak pressure is found as the biodiesel content decreases. B20, B50 and B100 have a shorter ignition delay than B0 and the ignition delay decreases with increasing biodiesel content. The liquid penetration decreases with decreasing biodiesel content. Moreover, the integrated natural flame luminosity (INFL) increases with decreasing biodiesel content. Shorter flame (i.e., soot luminosity) duration and a longer delay between start of combustion (SOC) and the appearance of flame are found as the biodiesel content increases. The flame duration also increases with increasing ambient gas temperature for all fuels. Soot is lower and appears later at a lower ambient gas temperature, while it is burned out at around the same time. Near-zero soot mass was observed for all tested fuels at 700 K. A shorter soot formation process is observed for biodiesel fuels. The soot reduction using B20 and B50 is not obvious compared to B0 at a low temperature. But under the ordinary diesel engine operating condition at 1000 K, the soot reduction is significant. It is also found that the soot can be reduced by 60% and above when B100 is used in this study.
Gasoline and E85 Combustion Visualization and Particulate Matter Emission in a Production SIDI Engine With Optical Access
Authors: Lee Po-I , Feng Xiaoce , Lai Ming-Chia
Published: February 2014

The present study analyzes the relationship of diffusion flame and PM emission of pure gasoline (E0) and E85 in a spark-ignited direct injection engine at low coolant temperature with optical access on one side of combustion chamber for high speed visualization. Different operating conditions including injection timing, ignition timing, and air-fuel ratio (lambda) with two throttle positions (high and low load) are experimented with a high speed FTIR and an Engine Exhaust Particle Sizer (EEPS) to measure the engine-out emissions. The results show that fuel types and injection timing strongly impact particle size distribution, total concentration, and total mass of PM emission due to piston or cylinder liner wall-wetting. It is concluded that both E0 and E85 present diffusion flame with early injection timing, and the existence of diffusion flame seen in the images corresponds to higher particle mass; however, it does not necessarily represent higher particle number, which is also fuel dependent. In certain conditions, PM emission of E85 could be higher in terms of particle number.
Cost Benefit Analysis of Alternative Fuel and Motive Power
Authors: Pinney Chris , Shurland Melissa , Smith Brian
Published: February 2014

A research initiative by the Federal Railroad Administration (FRA) and Transportation Technology Center, Inc. (TTCI) was developed to better understand the potential cost and benefits of using alternative fuels for United States freight and passenger locomotive operations. The framework for a decision model was developed to evaluate the feasibility of these newly emerging technologies. Because these alternatives (fuels and engine designs) are at early stages of development, the objective is to identify the most feasible alternatives and support their future development.

Energy security policies developed by the US Department of Energy (DOE) and emission standards set forth by US Environmental Protection Agency (EPA) are driving most of the technology initiatives related to alternative fuels in the US. Identifying alternatives that may provide benefits in the areas of emissions and energy security in relation to their potential cost, safety, and operating efficiencies are the main analysis objectives of this study.

Some of the alternative energy sources being studied, and that may be in limited use are biomass, natural gas and coal. These energy sources have the potential to replace diesel fuel and provide power for locomotive operations. However, most are considered experimental by the railway industry. In most cases engine modifications or complete motive power design changes are required. As a result, the use of alternative fuels or locomotives that are different from current diesel engine designs represent only a small percent of the total railroad fleet. The main drivers for the decision model identified in this research effort are Cost, Energy, Security, Emissions, Safety and Efficiency. Under each decision driver there are multiple criteria that may be used for comparison between proposed alternatives. The goal of the decision model is to understand if the criteria under the decision drivers are independently a cost or benefit to industry stakeholders as compared to a baseline case.
Towards a Better Understanding of the Rail Grinding Mechanism
Authors: Zhi Shaodan , Zarembski Allan M. , Li Jianyong
Published: February 2014

Rail grinding continues to be one of the most effective techniques for extending rail life, improving wheel/rail contact behavior, and reducing the overall cost of track maintenance. While the ability to more effectively implement improved rail grinding programs continues to expand, the understanding of the grinding mechanism itself has not kept pace with the improved implementation. Thus, while railroad engineering and maintenance personnel have learned to better develop grinding patterns and profiles through empirical testing and field evaluation, the fundamental theoretical bases for the improved grinding performance have not kept pace.

One such fundamental area of understanding is the modeling of the rail grinding process itself, both individually, as a function of a single grinding motor on the head of the rail, and in the more complex configuration of multiple grinding motors in a range of patterns. This paper presents the results of research directly aimed at better understanding these mechanisms and then utilizing this better understanding to develop a detailed rail grinding model that allows for the accurate analysis of not only an individual grinding motor but also a full grinding train application, as a function of pattern and speed.

In the case of the single grinding motor on the head of the rail, this research looks at the fundamental mechanism associated with each cutting abrasive grinding grain in the grinding stone, and then expands that mechanism to a full 10 inch diameter grinding wheel as it cuts into the rail head at a defined angle and speed. Using actual rail profile data and grinding data, a theoretical grinding wheel model is developed and then calibrated with wheel test data and actual grinding (field) data.

This single motor model is then expanded into a full grinding train model, such as for a 96 stone grinding train with 48 motors per rail, where it is able to analyze the full sequence of 48 motors as each motor individually and sequentially removes metal from the rail head. The resulting analysis is sensitive to such key factors as grinding speed, and the key pattern parameters of motor angles, sequence and power. The model is then calibrated to and compared with actual full scale rail grinding metal removal data from a major Class 1 railroad.

Such an analysis tool allows railroads to analyze the performance of different grinding patterns in a real world operating setting, to improve their rail grinding practices and take further advantage of new technologies in rail grinding to better manage the grinding process and improve planning of grinding activities.
Modern Uncertainty Quantification Methods in Railroad Vehicle Dynamics
Authors: Bigoni D. , Engsig-Karup A. P. , True H.
Published: February 2014

This paper describes the results of the application of Uncertainty Quantification methods to a simple railroad vehicle dynamical example. Uncertainty Quantification methods take the probability distribution of the system parameters that stems from the parameter tolerances into account in the result. In this paper the methods are applied to a low-dimensional vehicle dynamical model composed by a two-axle truck that is connected to a car body by a lateral spring, a lateral damper and a torsional spring, all with linear characteristics.

Their characteristics are not deterministically defined, but they are defined by probability distributions. The model — but with deterministically defined parameters — was studied in [1] and [2], and this article will focus on the calculation of the critical speed of the model, when the distribution of the parameters is taken into account.

Results of the application of the traditional Monte Carlo sampling method will be compared with the results of the application of advanced Uncertainty Quantification methods [3]. The computational performance and fast convergence that result from the application of advanced Uncertainty Quantification methods is highlighted. Generalized Polynomial Chaos will be presented in the Collocation form with emphasis on the pros and cons of each of those approaches.
Improved Quality Truck Castings
Authors: Jones Kerry
Published: February 2014

Component failure in bolsters and side frames remains a problem for both railroads and suppliers, causing expensive repairs and even derailments. To understand and combat this problem, an evaluation of the steel was required.

Bolsters were obtained from several suppliers to evaluate the current state of Association of American Railroads (AAR) M-201 standard for Grade B+ cast steel. Charpy impact and tensile test samples were machined from critical areas of these castings and tested at an independent laboratory. Distinct differences were found in processes and in mechanical properties between some suppliers. Supplier names are not identified in this paper.

Based on the chemical and mechanical testing results and data analysis, changes to AAR M-201 Grade B+ requirements have been proposed. Additional bolsters have been obtained for further testing. These bolsters will incorporate the proposed changes to the standard and the same mechanical testing will be performed on them to determine the effectiveness of the proposed changes. Full scale static or fatigue testing will be conducted on additional bolsters.

A survey of scrapped bolsters and side frames from several railcar producers and reclaim operations was conducted to determine the leading causes of failures of components removed from service. These results form the basis for a database that can be used to identify failure trends.
Determining Transfer Length in Pre-Tensioned Concrete Railroad Ties: Is a New Evaluation Method Needed?
Authors: Zhao Weixin , Beck B. Terry , Peterman Robert J. , Wu Chih-Hang John , Lee Grace , Bodapati Naga Narendra B.
Published: February 2014

The transfer length is perhaps the most significant KEY indicator of the bond quality between reinforcing wire/strand and concrete, and its measurement in pre-tensioned concrete railroad ties can enable concrete tie producers to identify problem ties before they are put into service. The 95% AMS method is the traditional method used to determine the transfer length from measurements of surface strain. The method generally presumes the underlying existence of a bilinear strain profile. During recent field trips to six concrete railroad tie plants, we conducted hundreds of transfer length measurements on concrete railroad cross-ties using a newly developed automated Laser Speckle Imaging device. It has been observed that many of the strain profiles depart significantly from this underlying bilinear profile, and bring to question the general validity and applicability of the 95% AMS (95% Average Maximum Strain) method. This paper discusses the difficulties with accurate determination of transfer length in various practical situations using the traditional 95% AMS method. Deviations of the strain profiles from the simple bilinear shape are shown to be partially due to the non-prismatic shape of typical concrete railroad ties. In addition, computational evidence suggests that the underlying strain distribution may be exponential in nature, with an asymptotic approach to the fully-developed compressive strain, potentially superimposed on the non-prismatic problem identified above. These departures are discussed along with proposed solutions to the basic problem of accurate transfer length assessment.
ASME Rail Transportation Division’s Historical Mechanical Engineering Landmarks: Preserving History and Heritage for the Future
Authors: Lonsdale Cameron , Bieber Allen , Burshtin Michael
Published: February 2014

The ASME Rail Transportation Division (RTD), founded in 1920 as the Railroad Division, is one of the oldest and most active of ASME’s 37 Divisions and Subdivisions. Today RTD promotes the engineering profession within the railway industry, and holds two technical conferences per year. A wide variety of topics are covered at the conferences including subjects related to freight, passenger and locomotive operations and maintenance, infrastructure improvements, mechanical components, and safety research. ASME RTD also has a program for designating historical mechanical engineering Landmarks within the railway industry. This paper briefly outlines the overall scope and purpose of the ASME Landmarks program. The paper then describes the many existing ASME Historical Mechanical Engineering Landmarks related to the railway industry, such as the Pennsylvania Railroad GG1 electric locomotive, the Manitou and Pikes Peak Cog Railway in Colorado, and the Norfolk and Western 611 Class J steam locomotive. The authors discuss potential railway industry additions to the RTD Landmarks list, and review potential ways to conduct the Landmark selection process for the future.
Next Generation Passenger Brake Equipment Development
Authors: Jamieson Paul E. , Gordon Jeffrey
Published: February 2014

Passenger brake equipment has evolved since George Westinghouse first demonstrated the straight air brake could successfully stop a train and avoid an incident in Pittsburgh, PA. Until recently, the transmission of commands through the pneumatic brake pipe has been the preferred method for brake control. Various configurations have been used to assist the command transmission with the most common being analog (on-off) electrical train lines. Data buses such as the Multifunction Vehicle Bus (MVB) and Ethernet have been used in regional train applications. These applications were for trains limited in length and were not suited for freight brake applications. The AAR has adopted a powered trainline control referred to as AAR S-4200 ECP (electrically controlled pneumatics). ECP has been successfully implemented throughout the heavy haul freight operation and has been recommended by the FRA for the future general rail system environment. Intercity and regional operations operate on the same general rail system therefore a strong case exists for adopting the AAR S-4200 technology for passenger rail operations. This paper will address the issues involved in applying the AAR S-4200 technology. These issues include assuring the technology will operate safely intermixed with existing pneumatic and pure ECP trains, emulation of the existing pneumatic brake equipment to minimize in-train forces, meeting the federal regulations related to passenger brake equipment, implementing cab car control which is common in push-pull (regional) operations, developing the necessary standards for the passenger ECP brake technology and initial demonstration of that technology.