bluuebunny/crossref_metadata_2025 huggingface dataset:
Orthogonal Experimental Study on Lime Shaft Furnace Briquettes as a Coke Substitute
Authors: Peng Hao-Yi , Zhou Ping , Zhou Jie-Min , Tu Fu-Bing
Published: August 2009

This paper studied the lime-shaft-furnace briquette used as a substitute for coke with an orthogonal experiment. The main material of briquette was the low-rank anthracite from Jinzhunshan of Hunan, China. The binder of briquette in this experiment was a compound binder including the magnesium-base curing agent, activator, biomass fiber and calcium lingosulfonate. The orthogonal table of L27(313) was chosen in this experiment and its factors consist of the magnesium-base curing agent, activator, biomass fiber, calcium lignosulfonate, mixture ratio of bituminous coal, briquetting pressure, briquetting water and size-composition of anthracite. The original compressive strength, original curshing strength, cold compressive strength, cold crushing strength, hot compressive strength and the heat stability of the briquettes made in this experiment were tested according to the Chinese relevant briquette test national standards. The test results were processed utilizing the method of the total probability formula evaluation. Based on the range analysis and analysis of variance, the optimal component of the compound binder and correlative key briquetting parameters were obtained, namely, 4 percent of magnesium-base curing agent, 1 percent of biomass fiber, 1 percent of activator, 0.12 percent of calcium lignosulfonate, and 20kN briquetting pressure, 17 percent of briquetting water, 10 percent mixture ratio of bituminous coal and the size-composition of anthracite with 58 percent of less than 0.5mm size, 14 percent of between 0.5mm and 1.0mm size, 17 percent of between 1.0mm and 2.0mm size and 11 percent of between 2.0mm and 3.0mm size. Analyzed were the mechanism of the compound binder and the optimal parameters of briquetting technics. The experimental results showed that the lime-shaft-furnace briquette prepared according to the optimal scheme obtained in this experiment could basically demand the industrial production of lime-shaft furnace as the substitute for coke.
Mechanism of Rewetting Initiation of Hot Dry Surface in Saturated and Subcooled Film Boiling
Authors: Ohtake Hiroyasu , Kobayashi Shingo , Koizumi Yasuo
Published: August 2009

The behavior of rewetting on high superheated surface, focusing on rewetting temperature during collapse of saturated and subcooled film boiling was investigated experimentally and analytically. Saturated and subcooled film-boiling experiments were conducted by using a Silicon wafer with 20 mm length, 20 mm width and 0.5 mm thickness and pure water at atmospheric condition. Both pool boiling and impingement jet experiments were preformed in the present study. Then, the present experimental results were examined by using hydrodynamics instability on liquid-vapor interface (Rayleigth-Tayor instability) and a heat conduction model (rewetting model under a falling-flow of a liquid layer). Some physical parameters on Rayleigh-Taylor instability, for example released period of bubble from vapor film on a heater, generated volume rate of vapor and so on, were estimated by using Two-Phase Boundary Layer theory of saturated and subcooled film boiling. The present analytical results showed that as the liquid subcooling was high, MHF temperature was higher. Namely, the predictions agreed with the present experimental results and Dhir-Purohit’s correlation.
Heat Transfer in Pipe Flow
Authors: Fakheri Ahmad
Published: August 2009

A simple procedure using spreadsheets is presented where the temperature distribution for laminar flow in a circular pipe is determined from the entrance of the pipe up to the fully developed region is calculated numerically. The results are then used to show the different features of internal flow like constancy of Nusselt number. The solution is presented for both isothermal and uniform heat flux boundary conditions and are then compared with available correlations.
Combined Force and Moment in a Three Dimensional Model of Elastic Contact of Nominally Flat Rough Surfaces
Authors: Sepehri A. , Farhang K.
Published: August 2009

In this paper we consider the contact between two rectangular rough surfaces that provide normal and tangential contact force as well as contact moment to counteract the net moment imposed by the applied forces. The surfaces are permitted to develop slight angular misalignment and thereby contact moment is derived. Through this scheme it is possible to also define elastic contribution to friction since the half-plane tangential contact force on one side of an asperity is no longer balanced by the half-plane tangential force component on the opposite side. The elastic friction force however is shown to be of a much smaller order than the contact normal force. Approximate closed form equations are found for contact force and moment as functions of separation, asperity radius of curvature sum, mean plane slope and nominal contact dimension. The approximate equations are shown to give error within seven percent.
Buoyant Flow and Heat Transfer in a Conducting Baffle
Authors: Boetcher S. K. S. , Kulacki F. A.
Published: August 2009

A numerical simulation of transient two-dimensional negatively buoyant flow into a straight baffle situated below an isothermal circular cylinder is performed. Both an adiabatic and a highly conducting baffle are considered over a range of Rayleigh numbers, 106 < RaD < 107. During the quasi-steady-state period, the surrounding fluid is effectively considered infinite in extent and at constant temperature. It is found that in general, the conducting baffle is at a disadvantage in maintaining a short attachment length which is needed to optimally slow the flow to prevent mixing. Qualitative flow fields are shown and heat transfer rates to the cylinder are calculated at the quasi-steady state.
Dynamic Analysis of Semi-Flexible Multibody Systems: Coordinates Relatives Method
Authors: Mouhingou Alexis , Azouz Naoufel
Published: August 2009

This work presents the dynamic modelling of a multibody systems in cross form constituted of a central body which is connected four flexible arms, at each end of arm is connected a rotor. A particular attention is given to the influence of flexibility on the dynamic behaviour of system. For elaborate the complete dynamic model, one consider the sub-structuration technique in using the Lagrangian approach based on the relatives coordinates method of central body. One establishes then the mathematics equations permitting to obtain the dynamic model of motion for the simulation and the control study. The aerodynamic loads and the gravity force are taking into account for the dynamic complete model. At the end, one considers the case of stationary flight of a miniature Quadrotor. The numerical results permit to simulate the motion of Quadrirotor in flight. But also to compare the flexible and rigid model in order to resort the flexibility effects.
Optimization of Refrigeration Systems for High-Heat-Flux Microelectronics
Authors: Phelan P. E. , Gupta Y. , Tyagi H. , Prasher R. , Cattano J. , Michna G. , Zhou R. , Wen J. , Jensen M. , Peles Y.
Published: August 2009

Increasingly, military and civilian applications of electronics require extremely high heat fluxes, on the order of 1000 W/cm2. Thermal management solutions for these severe operating conditions are subject to a number of constraints, including energy consumption, controllability, and the volume or size of the package. Calculations indicate that the only possible approach to meeting this heat flux condition, while maintaining the chip temperature below 50 °C, is to utilize refrigeration. Here we report an initial optimization of the refrigeration system design. Because the outlet quality of the fluid leaving the evaporator must be held to approximately less than 20%, in order to avoid reaching critical heat flux, the refrigeration system design is dramatically different from typical configurations for household applications. In short, a simple vapor-compression cycle will require excessive energy consumption, largely because of the superheat required to return the refrigerant to its vapor state before the compressor inlet. A better design is determined to be a “two-loop” cycle, in which the vapor-compression loop is coupled thermally to a primary loop that directly cools the high-heat-flux chip.
Guided Axon Growth by Gradients of Adhesion in Collagen Gels
Authors: Sundararaghavan Harini G. , Monteiro Gary A. , Shreiber David I.
Published: August 2009

During development, neurites are directed by gradients of attractive and repulsive soluble (chemotactic) cues and substrate-bound adhesive (haptotactic) cues. Many of these cues have been extensively researched in vitro, and incorporated into strategies for nerve and spinal cord regeneration, primarily to improve the regenerative environment. To enhance and direct growth, we have developed a system to create 1D gradients of adhesion through a 3D collagen gel using microfluidics. We test our system using collagen grafted with bioactive peptide sequences, IKVAV and YIGSR, from laminin — an extra-cellular matrix (ECM) protein known to strongly influence neurite outgrowth. Gradients are established from ∼0.37mg peptide/mg collagen – 0, and ∼0.18 mg peptide/mg collagen – 0 of each peptide and tested using chick dorsal root ganglia (DRG). Neurite growth is evaluated 5 days after gradient formation. Neurites show increased growth in the gradient system when compared to control and biased growth up the gradient of peptides. Growth in YIGSR-grafted collagen increased with steeper gradients, whereas growth in IKVAV-grafted collagen decreased with steeper gradients. These results demonstrate that neurite growth can be enhanced and directed by controlled, immobilized, haptotactic gradients through 3D scaffolds, and suggest that including these gradients in regenerative therapies may accelerate nerve and spinal cord regeneration.
Applications of Artificial Neural Networks on Ground Vehicle Systems - Modeling and Diagnostics: A Literature Survey
Authors: Cao Ming
Published: August 2009

This study reviews progresses on the application of Artificial Neural Networks (ANNs) in ground vehicle system modeling and diagnostics since 1997. Fundamentals of ANN-based system modeling are laid out, and utilized to frame the review. Areas covered in this research include modeling of vehicle components, prediction of vehicle dynamics, modeling of safety-related driver behaviors and prediction of vehicle rollover, as well as vehicle system prognostics. As this review shows, most applications addressed powertrain system and its components (includes engine, transmission parts such as friction components etc.). Besides characterizing different ANN modeling / prognostic techniques for ground vehicle applications, this study also points out future directions in this area, and serves as the foot step for the future applications of ANNs in ground vehicles.
Research on Heat Flux Distribution in Deep Grinding
Authors: Zhu D. H. , Li B. Z. , Yang J. G.
Published: August 2009

This paper studies the heat transfer mechanism in deep grinding process, especially the heat flux to the workpiece. On the basis of triangle moving heat source, a quadratic curve heat flux model in the grinding zone was developed to determine the heat flux distribution and to estimate the surface temperature of workpiece. From the calculated theoretical expression of heat flux to the workpiece, the quadratic curve heat flux can be understood as the superposition of square law heat flux, triangular heat flux and uniform heat flux in the grinding zone. Then four heat flux models using the determined amount of heat flux were applied to estimate the workpiece surface temperatures which were compared with that measured by the embedded thermocouple. It has been found that the quadratic curve heat flux distribution seems to give the best match with measured and theoretical temperature, although square law heat flux model is good enough to predict the temperature.
Friction-Induced Dynamics of Axially-Moving Media in Contact With an Actively-Positioned Surface
Authors: Kartik V. , Eleftheriou Evangelos
Published: August 2009

The dynamics of an axially-moving flexible medium are examined in the context of an application where the medium is partially supported by a frictional surface, that actively-orients itself relative to the direction of transport. The stability and motion of the medium are of interest in a magnetic tape data storage application where the orientation of a sensing surface is continuously altered in order to ‘follow’ the medium’s motion. Moving media that are in contact with such guiding surfaces experience friction excitations induced by the relative motion in addition to what is observed with a stationary guiding surface. Friction-induced bending moments, as well as tension fluctuation beyond the permissible limits for the flexible material can erode the potential benefits of such active positioning. This paper describes some of these dynamic phenomena using the simplified example of a planar guiding surface whose orientation is dynamically altered relative to the moving medium. A physical model for the friction-induced excitation of the moving medium is developed, and the dynamics are analyzed for their effect on critical design parameters such as the achievable bandwidth of the active control algorithm, as well as with respect to constraints on the geometry and positioning of the guiding surface.
Passive Vortex Micromixers Utilizing Hybrid Laminations
Authors: Chen Jyh-Jian , Luo Yu-Cheng , Su Shin-Hau , Jheng Nai-Yu
Published: August 2009

This theoretical investigation analyzed the three-dimensional momentum and mass transfer characteristics arising from the multiple inlets and single outlet in micro chamber which consists of a right square prism, an octagonal prism or a cylinder. The effects of various geometric parameters, inlet velocities, and the types of lamination on the mixing characteristics were investigated, and the results were presented in terms of flow fields, concentration profiles, and mixing index. Numerical results indicated that vortex flow and numbers of inlets dominate the mixing index. At larger Taylor number, more inertia caused the powerful vortex flow in the chamber, and the damping effect on diffusion was diminished, which then increased the mixing performance. Furthermore, passive micromixers utilizing hybrid laminations showed better mixing results than those with parallel laminations.
Simulation of Vortex Shedding Behind Square and Circular Cylinders
Authors: Bagherian Behtash , Moin Hossein , Passandideh-Fard Mohammad
Published: August 2009

Many studies have been conducted on downstream flows behind two-dimensional cylindrical sections for low Reynolds numbers. The vortex shedding phenomenon occurs in fluid flows over buildings, trailer trucks, bridge piers, heat exchangers, pipelines in the sea, etc. This phenomenon, which is due to the flow instability in the wake region results in a periodic oscillation of drag and lift forces. In experimental studies, visualization techniques such as hot wire and Laser Doppler Velocimetry (LDV) are usually employed. By performing extensive measurements and using the concept of curve fitting, correlations have been obtained for Strouhal number variation with Reynolds number. In addition to experimental works, some analytical studies on complex wake structures of forced and freely oscillating cylinders have been undertaken. Recently, numerical models have been introduced in order to simulate this phenomenon. Khalak and Williamson made several Direct Numerical Simulation (DNS) studies on freely oscillating cylinders for Re up to 350. Low Reynolds flows (up to 800) over square and circular cylinders are simulated based on a numerical method where transient 2D Navier-Stokes equations are solved. In simulations, the fluid was assumed water with properties at 25°C. The model predictions for pressure fluctuations and the variation of Strouhal number (St) with Reynolds (Re) were compared with those obtained from experiments and correlations. In this numerical model we also compared drag force (CD) against Reynolds (Re). Under sharp rising distribution and horizontal asymptotic regime which are two major parts of St-Re variations, the model results agree well with measurements. Both simulations and experiments reveal that the St-Re variations do not depend on the shape of the cylinder. The model results agreed well with measurements.
Teaching Consumer Product Design to Engineering Students
Authors: Condoor Sridhar S. , Doty Heath
Published: August 2009

Consumer product design blends engineering and industrial design principles, and marketing strategies to bring functional, aesthetic products to market. While competitions motivate a diverse set of students to churn out products/ventures, a systematic approach for tackling consumer product design tasks and case studies that demonstrate the approach greatly benefit a number of students by focusing their design efforts. The paper elaborates such an approach using a case study highlighting the thought process. The case study involves the design of an innovative keychain. While the case study was primarily mechanical engineering in scope addressed by a student team of mechanical engineers, the approach outlined in the paper is generic and can be applied to product designs involving other disciplines.
Teaching Design in Context
Authors: Boettner Daisie , Byers Lynn K. , Crawford Bobby G. , Tamm Gunnar , Rogers John , Jones Tony , Rounds Michael
Published: August 2009

As a result of recent curriculum revisions, the mechanical engineering faculty at the United States Military Academy teaches the formal design process “just in time” for students to apply the process to their capstone design projects. The design process consists of several phases and incorporates many engineering tools. During the initial offering of the course, Mechanical Engineering Design, instructors assigned students to capstone design teams early in the course. As the instructor taught the design process, team members applied the concepts to their capstone project. Based on instructors’ and students’ feedback, faculty revised the course structure to teach the design process in the context of a simple, in-class design project (design a portable illumination device) during the first half-semester. All in-class exercises were collaborative, hands-on experiences based on the project. To reinforce topics introduced in class and ensure all students develop a firm foundation in the design process, a separate common customer need (a device to store a West Point class ring) was the focus of all individual homework. Each student developed a design, built a prototype, and wrote an individual design report. Subsequent to formal design process instruction, students formed capstone teams and began their one and one-half semester capstone design projects. Results indicate that students more thoroughly understood the design process and its associated engineering tools allowing capstone teams to progress more efficiently through conceptual design; order parts, build prototypes, and test prototypes much earlier than the previous year; and enjoy a successful capstone experience.
Focusing of Airborne Sound by Heated Wires
Authors: Cai Liang-Wu , Angelov Mitko , Cervera Francisco , Sa´nchez-Dehesa Jose´
Published: August 2009

In this paper, we discuss the mechanism of focusing airborne ultrasound using heated wires. The heated wire generated a radially stratified temperature field surrounding the wire. The temperature field subsequently caused both the sound speed in the air and the mass density of the air to become radially stratified. This radial profile causes the impinging plane ultrasonic wave to form two strong beams in the forward direction, with a very strong shadow region. When multiple such wires are placed into a grid, the beams from adjacent wires form a sharply focused region. In this paper, experiment details are discussed. The analysis of single and multiple scattering of a planar acoustic wave by such fields are performed using experimentally measured temperature field, and compared with the experimentally measured acoustic field.
Understanding Microdroplet Formations for Biomedical Applications
Authors: Desai Salil , Moore Anthony , Harrison Benjamin , Sankar Jagannathan
Published: August 2009

This paper focuses on understanding microdroplet formation of sodium alginate biopolymer at various concentrations utilizing drop-on-demand inkjet technology. We investigate the effect of sodium chloride on the rheology of sodium alginate and derive a correlation between the size of the droplet versus the size of the microcapsules formed. Varying sizes of microcapsules are formed based on different concentrations of calcium chloride solvent. This understanding will give insight for fabricating drug delivery capsules and tissue scaffolds that are subject to extreme ambient conditions when interfaced with in-vivo environments.
Biodegradable Mg for Bone Implants: Corrosion and Osteoblast Culture Studies
Authors: Yun YeoHeung , Dong Zhongyun , Yang Dianer , Shanov Vesselin , Xu Zhigang , Sfeir Charles , Doepke Amos , Schulz Mark
Published: August 2009

Corrosion and cell culture experiments were performed to evaluate magnesium (Mg) as a possible biodegradable implant material. The corrosion current and potential of a Mg disk were measured in different physiological solutions. The corrosion currents in cell culture media were found to be higher than in deionized water, which verifies that corrosion of Mg occurs faster in chloride solution. Weight loss, open-circuit potential, and electrochemical impedance spectroscopy measurements were also performed. The Mg specimens were also characterized using an environmental scanning electron microscope and energy-dispersive x-ray analysis (EDAX). The x-ray analysis showed that in the cell culture media a passive interfacial layer containing oxygen, chloride, phosphate, and potassium formed on the samples. U2OS cells were then co-cultured with a Mg specimen for up to one week. Based on visual observation, cell growth and function were not significantly altered by the presence of the corroding Mg sample. These initial results indicate that Mg may be suitable as a biodegradable implant material. Future work will develop small sensors to investigate interfacial biocompatibility of Mg implants.
Near-Field Thermal Radiation: Comparison of Numerical Results and Experiments
Authors: Narayanaswamy Arvind , Shen Sheng , Chen Gang
Published: August 2009

Near–field radiative transfer between two objects can be enhanced by a few order of magnitude compared to the far–field radiative transfer that can be described by Planck’s theory of blackbody radiation and Kirchoffs laws. We have developed a numerical technique to determine the near–field thermal radiative transfer between two spheres. We have measured near–field thermal radiation between a silica sphere and a flat silica substrate as a function of gap between them using an bi–material cantilever as a thermal sensor. The experimental results show qualitative agreement with numerical results. The results of this work indicate that the proximity force approximation, widely used to determine forces between curved objects, is not applicable to near–field radiative transfer between curved objects.
Experimental Measurement of Laminar Axisymmetric Flow Through Confined Annular Geometries With Sudden Inward Expansion
Authors: Goharzadeh Afshin , Rodgers Peter
Published: August 2009

In this paper separated and reattaching laminar flows produced by a sudden inward expansion within confined annular geometries are experimentally studied. Using Particle Image Velocimetry (PIV), combined with refractive index matching, the structure of fluid flow at the expansion region was investigated. Detailed measurement of the velocities, the reattachment length (Lr) and the relative eddy intensity (ξ) are obtained for two different expansion ratios of ε = 1.4 and 1.6. The measured variation of the reattachment length as a function of Reynolds number (50 < Re < 600) was found to be non-linear for these expansion ratios. Eddy intensity was found to depend strongly on both Reynolds number and expansion ratio, with the relationship between ξ and Re being non-linear. Overall corresponding numerical predictions obtained by Nag & Datta [1] are in good agreement with the measurement results presented.
Numerical Simulation of Immersion Quench Cooling Process: Part I
Authors: Srinivasan Vedanth , Moon Kil-min , Greif David , Wang DeMing , Kim Myung-hwan
Published: August 2009

In this article, we describe a newly developed modeling procedure to simulate the immersion quench cooling process using the commercial code AVL-FIRE. The boiling phase change process, triggered by the dipping hot solid part into a subcooled liquid bath and the ensuing two-phase flow is handled using an Eulerian two-fluid method. Mass transfer effects are modeled based on different boiling modes such as film or nucleate boiling regime prevalent in the system. Separate computational domains constructed for the quenched solid part and the liquid (quenchant) domain are numerically coupled at the interface of the solid-liquid boundaries using the AVL-Code-Coupling-Interface (ACCI) feature. The advanced ACCI procedure allows the information pertaining to the phase change rates in the liquid domain to appear as cooling rates on the quenched solid boundaries. As a consequence, the code handles the multiphase flow dynamics in the liquid domain in conjunction with the temperature evolution in the solid region in a tightly coupled fashion. The methodology, implemented in the commercial code AVL-FIRE, is exercised in simulating the quenching of solid parts. In part I of the present research, phase change models are validated by simulating a work piece quenching process for which measurement data are available for various water temperature ranging from 20C to 80C. The computations provide a detailed description of the vapor and temperature fields in the liquid and solid domain at various time instants. In particular, the modifications arising in the liquid-vapor flow field in the near vicinity of the solid interface as a function of the boiling mode is well accommodated. The temperature history predicted by our model at different monitoring points, under different subcooling conditions, correlate very well with the experimental data wherever available. In part II, the model is further applied to real engine cylinder head quenching process and assessment is made for the cooling curves for various measuring points. Overall, the predictive capability of the new quenching model is well demonstrated.
Numerical Simulation of Immersion Quench Cooling Process: Part II
Authors: Srinivasan Vedanth , Moon Kil-min , Greif David , Wang DeMing , Kim Myung-hwan
Published: August 2009

In this article, we present the numerical simulation of a real cylinder head quenching cooling process using a newly developed approach for immersion quenching described in Part I of this research. Computational grids, consisting of 1.6 million cells in the coolant (liquid) domain and 1.5 million cells in the solid region, are utilized to perform the ACCI coupled quenching simulation implemented in the commercial code AVL-FIRE framework. Multitude of flow features such as vapor pocket generation, bubble clustering and their disposition are captured very effectively during the computation. Comprehensive descriptions of the flow field information and the temperature pattern in the solid at different time instants are provided. A comparison of the registered temperature readings at different monitoring locations with the numerical results generates an overall very good agreement. Our results indicate the presence of intense non-uniformity in the temperature distribution within the solid region which is of grave importance in evaluating the stress and fatigue patterns generated in the quenched object. The capability of the quenching model in simulating a real-time immersion quenching application process and the efficiency in reducing the overall model size by the application of the ACCI procedure is well demonstrated.
Aerodynamic Comparison of Straight Edge and Swept Edge Wind Turbine Blade
Authors: Amano R. S. , Malloy Ryan J.
Published: August 2009

Recently there has been an increase in the demand for the utilization of clean renewable energy sources. This is a direct result of a rise in oil prices and an increased awareness of human induced climate change. Wind energy has been shown to be one of the most promising sources of renewable energy. With current technology, the low cost of wind energy is competitive with more conventional sources of energy such as coal. This however is only true in areas of high wind density. These areas are not as abundant and therefore the number of profitable sites is limited. This paper explores the possibility increasing the number of profitable sites by optimizing wind turbine blade design for low wind speed areas. The two methods of optimization that are investigated are first, optimizing the angle of attack and chord length for a given airfoil cross section at different positions along the blade and second implementing a swept blade profile. The torque generated from a blade using only the first optimization technique is compared to that generated from a blade using both techniques as well as that generated by NTK500/41 turbine using LM19.1 blades. Performance will be investigated using the CFD solver FLUENT.
Experimental and Computational Analysis of Brain Deformations in Linear Head Impact
Authors: Darvish Kurosh , Shafieian Mehdi , Laksari Kaveh , Barabadi Banafsheh , Parenti Cristina
Published: August 2009

In this study two-dimensional physical and finite element models of human head under linear deceleration were developed. 5% gelatin was used as the brain substitute material with similar viscoelastic properties. The experimental strains and pressure during 55G impacts were measured to validate the element formulations used in the computational models. The Lagrangian and Arbitrary Lagrangian Eulerian (ALE) formulations were used in the FE models. It was shown that without Cerebrospinal Fluid (CSF), the Lagrangian strains passed the 10% threshold of axonal injury. At the presence of CSF, no significant strain was observed while 6 to 8 times increase in the intracranial pressure was recorded. The FE models showed similar trends for strain, stress, and pressure but were generally more aggressive than the experimental results. The ALE model was more stable and its effective damping was more consistent with the experimental data.
Two-Dimensional Numerical Simulations of a Biphasic Representation of Human Tibia in Car-Pedestrian Accidents
Authors: Chen Haibin , Cheng Xuemei , Yang King H.
Published: August 2009

A two-dimensional poroelastic model of the tibia was developed to improve the understanding of injury mechanism of tibia during car-to-pedestrian impacts. A “poroelastic” approach was utilized to establish the governing equations of human tibia, and the finite element method was applied to solve these governing equations. Both the cortical and cancellous components of tibia were represented using a poroelastic material model consisted of a solid and a fluid phase. The geometry of the model was reconstructed from CT scans of the left tibia of a living human volunteer. A lateral-medial impact direction was selected in the simulation analysis. Correspondingly, the tibia poroelastic model was validated against published shearing experiments with the whole PMHS tibia. The model predictions showed good agreement against the PMHS test data. The developed poroelastic model can be used as a helpful tool to investigate injury mechanism of the tibia in car-to-pedestrian accidents.
Influence of Socio-Economy in the Next Generation of Thermal Management Solutions for Electronics Consumer Products
Authors: Refai-Ahmed Gamal
Published: August 2009

The past few decades have seen a number of countries around the world emerge as a growing market for high performance computers. This present study examines, in more detail, how socio-economic influences are shaping the demand function and how some computing landscapes are changing as a consequence. This study is addressing one of the key initiatives to enable 50 percent of the world’s population with access to the World Wide Web. Furthermore, this investigation is addressing the challenges for electronics packaging Engineers and Researchers. Therefore, the rational of the developed technology based on the understanding target market and usages will be given. The impact of addressing the heat dissipation and managing the use of the raw materials of the intended products are discussed. In addition, how the electronics packaging engineers can focus on developing affordable innovative technology. Finally, the impact of all of the above is examined in developing the cost effective solution from a global point of view.
Improvement of Reliability of Executive Mechanisms of Railway Ice-Cars Compressors
Authors: Sharashenidze Guri , Mgebrishvili Nikoloz , Kurtanidze Pavle , Dolidze Mamuka , Sharashenidze Sergo
Published: August 2009

A compressor of the ice-car refrigerating plant is characterized by uninterrupted operation that is necessary to maintain a refrigerating cycle in the car. A problem of operating lifetime, unfailing operation and reliability of the compressor depends on functional operation of its basic executive mechanism — crank mechanism. An original dynamic model of the executive crank mechanism is elaborated by the authors. Research of dynamical parameters of the executive crank mechanism according to real dynamic model is carried out. Phenomenon of variable eccentricity caused by the wear of hinges and conditions of its existence are established. Expressions corresponding to dynamical analysis are obtained. Use of the elaborated dynamic model in modern ice-car refrigerating plants ensures a significant economic effect — it decreases: planned repair expenses of refrigerating plants and compressors, ice-car downtime. At the same time it increases the length of the repair period and improves operating characteristics.
Estimation of Residual Stress Distribution in Railroad Wheels
Authors: Sura Venkata S. , Mahadevan Sankaran
Published: August 2009

Residual stresses in railroad wheel rims significantly affect the wheel failure life; therefore, it is important to consider residual stresses for wheel failure analysis. In this paper, an advanced computational methodology is developed to estimate residual stresses developed during both the manufacturing process and under service conditions. To estimate the residual stresses in the wheel, three-dimensional decoupled thermal-structural analyses are performed. To simulate the manufacturing process, thermal analysis is performed with convection boundary conditions on the wheel surfaces. The temperature distributions obtained from this thermal analysis are input as loads for structural analysis. The results represent as-manufactured residual stresses. To simulate the thermal brake loading under service conditions, thermal analysis is performed using a heat flux boundary condition on the tread surface. Structural analysis is performed, including the estimated as-manufactured residual stress as initial stress, and using the temperature distributions obtained from thermal analysis of the on-tread braking. The resultant stresses represent the complex combination of residual stresses developed during both the manufacturing process and on-tread braking. The computed results are compared with the experimental data obtained at TTCI and the values reported in the literature.
Reducing Energy Costs With Electric, Diesel and Dual-Powered Locomotives
Authors: Vitins Janis
Published: August 2009

Typically, the costs for traction energy add up to 20% or more of the total train operating costs with electric locomotives in Europe. Therefore, there is a high incentive for the railroads to reduce energy consumption and thus to improve operating margins. Additionally, rising costs for energy as well as environmental aspects will increase the need to reduce energy consumption in the future. Firstly, on electric locomotives the largest energy savings are obtained from power regeneration at braking. In this mode the locomotive acts as a moving power generator feeding energy back into the catenary network. Savings are typically in the range of 10 to 30%. Secondly, the driving style has a high impact on energy costs. Energy consumption can be lowered by more than 20% through an energy conscious driving style compared to aggressive driving. Thirdly, the energy efficiency of the whole traction chain is important. Electric locomotives designed for AC catenaries have an overall energy efficiency of up to 86%. Locomotives designed for 1.5 or 3 kV DC catenaries can have an overall energy efficiency of up to 90%. New technologies can potentially help to increase the power efficiencies even further. Apart from using efficient diesel engines, the fuel costs of diesel-electric locomotives can be reduced much in the same way as with electric locomotives. Regeneration of braking power on diesel-electric locomotives is, however, limited to feeding the auxiliaries and head end power (HEP) to passenger coaches. In Europe the energy costs per hauled ton-km are typically much lower with electric than with diesel traction. This gives dual-powered locomotives the advantage of overall lower energy costs for operation on both electrified and non-electrified networks. First estimates show that the total energy costs (diesel and electric operation) can be reduced by more than 35% in a mixed network with 80% electrification with a dual-powered locomotive compared to a diesel locomotive running the same train on the same route. In addition, the dual-powered locomotive provides major cost savings and increased quality of service with a one seat ride.
Issues Surrounding the Measurement and Application of Vertical Track Stiffness Data
Authors: Read David M. , Plotkin Donald
Published: August 2009

Vertical track stiffness is widely considered to be a fundamental indicator of track strength and sustainability. Although measurement of the stiffness parameter is often thought of as being potentially useful for track condition assessment, fault diagnosis and/or maintenance planning purposes, specificity as to how or why is generally lacking. This paper will assess the potential value of measuring track stiffness by considering if the data provides information that: 1) is essentially different from that provided by other techniques, and 2) can be used to enhance current track management capabilities in ways the other techniques cannot. To answer these questions, the paper will describe the track stiffness parameter, discuss the issues surrounding its measurement, summarize related measurement technologies, examine potential applications of the data and discuss the benefits, if any, that track stiffness data might provide that are potentially superior to the related techniques.
A Collaborative On-Track Field Test Conducted to Verify the Laboratory Findings on Bearing Temperature Trending
Authors: Tarawneh Constantine M. , Kypuros Javier A. , Wilson Brent M. , Snyder Todd W. , Gonzalez Bertha A. , Fuentes Arturo A.
Published: August 2009

Over the last three years, numerous laboratory tests have been conducted with the goal of identifying the root cause of the temperature trending phenomenon observed in tapered roller bearings during their field service. The experimental efforts were successful in duplicating the temperature trending phenomenon in the lab, and concluded that vibration induced roller misalignment was responsible for this troubling phenomenon; yet field verification of these findings was still missing. To this end, a collaborative on-track field test was carefully planned and executed by The Amsted Rail Company, The Union Pacific Railroad (UP), Rail Sciences Inc. (RSI), and The University of Texas-Pan American (UTPA). A locomotive, a business car, and two coal cars — one fully loaded and one empty — were made available by the UP for the purposes of this test. Four bearings that exhibited temperature trending during the laboratory testing, and two other bearings that were set-out for temperature trending by the UP, were mounted next to six high impact wheels of at least 70 kips. The impact wheels were used as external vibration sources. Three of these wheels were placed under the fully loaded coal car, and the other three under the empty car. The remaining components used in the test were all defect free bearings and wheels. All sixteen bearings were instrumented with thermocouples and accelerometers, with four additional accelerometers monitoring the track joints and defects and the car pitch and bounce. This paper provides a summary of the initial analysis of the acquired data which indicates that the field test was successful in verifying the laboratory findings.
Evaluation of Forces on Derailed Wheels Using Soil Cutting Theory
Authors: Krueger Darrell R. , Dick Matthew G.
Published: August 2009

Much research has been performed on predicting the derailment of a rail car when properly situated on rails. However, less work has been performed on evaluating what happens to a railcar’s wheel after derailment. Recent work has used a simplified off-track ground friction coefficient to aid in the prediction of post-derailment car trajectories. This paper uses soil cutting theory to investigate the lateral and longitudinal forces acting on a derailed wheel in different soil types. Findings are compared to the use of the simplified off-track ground friction and may improve the accuracy of current derailment simulation techniques.
Pressure Pulse Technology for Boiler Cleaning
Authors: Bunton Mark A.
Published: August 2009

Steam or compressed air continue to be the typical cleaning mediums for long retractable (IK) sootblowers used to clean the convection section of the boiler. Advancements in steam/air nozzle technology have lead to improved cleaning in areas such as the secondary superheater, but due to issues with boiler tube erosion, advanced nozzles have not been routinely used in the convection section. Boiler tube erosion and the resulting forced outages due to tube leaks have consistently been an operational issue for many boilers. Sonic cleaning has offered the hope of cleaning without tube erosion, but cleaning results have been mixed. The energy created by sonic devices is more than an order of magnitude less than a sootblower jet and as a result have not been able to remove many types of deposits.
The Design and Operation of an Advanced NOx Control System on the New 636TPD MWC at the Lee County WTE Facility
Authors: Dainoff Alexander S. , Anacker Dennis
Published: August 2009

In September of 2007, a new 636TPD Municipal Waste Combustor was brought on line at the Lee County WTE Facility in Fort Myers, FL operated by Covanta Energy. This unit was the first new Waste to Energy unit built in the United States in a number of years and included a lower permitted daily average NOx emissions requirement of 110ppm @ 7%O2 while maintaining ammonia slip to less than 10ppm. To meet this new stringent NOx emissions requirement, the boiler was designed with advanced combustion controls including Flue Gas Recirculation combined with a urea based Selective Non-Catalytic Reduction Process to provide a combined NOx reduction of approximately 70% while maintaining the required ammonia slip. The SNCR System provided by Fuel Tech was designed with 3 levels of seven wall injectors installed in the upper furnace. Both boiler load and Furnace Gas Temperature were used as a feed forward control with the CEM NOx signal as a feed back to automatically select the injector levels and reagent feed rates to maintain the targeted NOx while also maintaining ammonia slip control. This paper will outline the design considerations, the details of the process and the operation of the systems on this unit.
Research on Feasibility of Different Incineration Systems for Paper Sludge
Authors: Zhang Zhixiao , Ma Jiade , Cai Weimin
Published: August 2009

A large amount of paper is recycled in China, that generates a significant amount of sludge and residue during the paper production process. Energy recovery by means of combustion in Waste-to-Energy (WTE) plants can be a possible candidate for sludge elimination. Currently, two incineration methods, distinguished as either direct incineration of partially dewatered sludge (generally 80% water content) or dried sludge incineration (dried to about 40% water content), are available. Research on comparison of fixed cost, operating cost and pollutant emissions between the two systems is presented. Fixed cost and steam consumption increase for the dried sludge incineration system though this method possesses many advantages, these include the decrease in consumption of auxiliary coal, service power and flue gas purificants. Moreover, main pollutant emission, such as SO2 and NOx, is significantly reduced. Chinese WTE managing regulations recommend no less than a 4:1 weight ratio of waste to auxiliary fuel fed into the incinerator. For a partially dewatered sludge direct incineration system, this weight ratio is about 5:1. However it reduces to 3.6:1 in a dried sludge incineration system. This is offset by a decrease in consumption of auxiliary coal and the overall weight ratio based on the entire plant increases to 7.5:1. The result suggests not only the technical and economic feasibility of a dried sludge incineration method, but also the feasibility of adopting the weight ratio of waste to auxiliary fuel based on entire WTE plant in the future regulation in China.
Winds of Change: Developing a 21st Century Energy From Waste Facility in Ontario
Authors: Januszkiewicz Mirka , Worster Shawn
Published: August 2009

Currently, over 70% of the non-hazardous solid waste generated in Ontario is disposed of in landfills. Approximately 45% of Ontario’s waste is disposed of in landfills located in Michigan. Disposal of residual waste in Ontario is undergoing a major shift. Pursuant to agreements made in 2006 between Ontario municipalities and federal and state representatives of Michigan, waste from Ontario municipalities will no longer be disposed in Michigan landfills post 2010. That has put enormous pressure on Ontario municipalities to seek alternative disposal solutions for the waste remaining after they reduce, reuse and recycle.
Analysis of the “Zero Waste” Management Option Using the Municipal Solid Waste Decision Support Tool
Authors: Thorneloe Susan A. , Weitz Keith A. , Miller Jesse
Published: August 2009

The U.S. Environmental Protection Agency’s Office of Research and Development (US EPA ORD) has developed a “Municipal Solid Waste Decision Support Tool”, or MSW-DST, for local government solid waste managers to use for the life cycle evaluation of integrated solid waste management options. The MSW-DST was developed over a five year period (1994–1999) with the assistance of numerous outside contractors and organizations, including the Research Triangle Institute, North Carolina State University, the University of Wisconsin-Madison, the Environmental Research and Education Foundation, Franklin Associates and Roy F. Weston. The MSW-DST can be used to quantify and evaluate the following impacts for each integrated solid waste management alternative: • Energy consumption, • Air emissions, • Water pollutant discharges, • Solid Waste disposal impacts. Recently, the MSW-DST was used by the U.S. EPA to identify solid waste management strategies that would help to meet the goal of the EPA’s “Resource Conservation Challenge.” In this effort, ten solid waste management strategies were evaluated for a hypothetical, medium-sized U.S. community, with a population of 750,000 and a waste generation rate of approximately 3.5 pounds per person per day. (Table 1). The assumed waste composition was based on national averages. A peer-reviewed paper on this research was published in 2008 by the American Society of Mechanical Engineers (ASME).