bluuebunny/crossref_metadata_2025 huggingface dataset:
Next Generation Technologies for Improving Product Planning and Development: An Industry Perspective
Authors: Jain Anurag , Thirugnanam Sathish Kumar , Narsingpurkar Atul , Panchal Jitesh H.
Published: April 2014

Successful product planning and development revolves around great innovation, effective implementation of new ideas, cross-functional collaboration, and right decision making before translating ideas into a right product portfolio, features and technology roadmaps, and finally launching them as successful products. Managing the product planning processes offers multiple challenges in the absence of a healthy idea pipe line, a good visibility into market and competition dynamics, lack of cross functional collaboration and finally, absence of an integrated process and system to support the complex information interplay. Organizations have, in past, adopted different process models and technologies ranging from product data management (PDM), product lifecycle management (PLM), knowledge management and collaboration solutions to address above challenges. However, there is a significant opportunity to leverage next generation technologies such as digital social networking (DSN), cloud computing, and big data management in conjunction with the traditional technologies to improve the efficiency and effectiveness of product planning and development.

This paper presents an industry perspective on the major potential areas where these next generation technologies can be leveraged in the early stages of design, particularly product planning. Specific examples from automotive design and manufacturing are used to illustrate the complementary nature of traditional technologies and the emerging web-based technologies. The paper discusses major industry trends and reviews academic research in this area, and concludes with the authors’ point of view on how the combination of these technologies can be leveraged for developing a profitable product portfolio. The paper also highlights specific research issues from technological and business process standpoint that need to be addressed for successful integration. The potential benefits of such integration include productivity improvements, improved product offerings, first time right & on time product launches.
Towards the Synthesis of Product Knowledge Across the Lifecycle
Authors: Witherell Paul , Kulvatunyou Boonserm , Rachuri Sudarsan
Published: April 2014

Product lifecycle management is an important aspect of today’s industry, as it serves to facilitate information exchange and management between most, if not all, stages of a product’s existence. As exchanged product information is inevitably subjected to multiple transformations and derivations, information transparency between lifecycle stages can be difficult to achieve. Synthesizing representations of product information across the lifecycle, by creating a lifecycle-stage-independent platform, can provide transparent access to information for both upstream and downstream applications.

In this paper, we review previous and ongoing efforts using ontologies as a means to support information integration and interoperability throughout the lifecycle of a product. We propose that existing efforts can be leveraged to create an upper-tiered ontology for product information. The resulting ontology, a core model for product lifecycle information, would support the synthesis and exchange of product information across lifecycle stages, improving access to this information and facilitating lifecycle thinking.

We discuss the use of ontologies as a means to create and link paradigm-independent representations. We discuss the translations that product information may face when integrated through ontologies, and the extent to which the integrity of the information can be preserved across the lifecycle. We investigate the role of information quality in the exchange and evolution of product information across the lifecycle. Finally, we discuss the application of an upper-tiered ontology, particularly the advantages offered by increased transparency and interoperability, as a means to support lifecycle thinking for mitigating a product’s sustainability impact.
Advanced Metallic Solution for Toe Cap Component
Authors: Costa Sérgio L. , Silva Joel V. , Peixinho Nuno , Mendonça João P.
Published: April 2014

In this paper the elasto-plastic behavior of the toe cap safety footwear component for three different Advanced High Strength Steels (AHSS) combined with new geometric models, was analyzed. The normative quasi-static compression test in the context of the experimental validation of different prototypes, and the conceptual orientation of those models with numerical simulation were performed. The study aimed to examine the potential energy absorption capacity for a substantial thickness reduction of slim toe cap models. A non-linear Finite Element Analysis of the plastic deformation mode with material properties as strain hardening of True-Stress-Strain extrapolated curves was considered. From experimental results it was found that the evolved geometric model had significant influence on the static stiffness and toe cap damage for a weight saving range of approx. 35 to 40%, compared with the original steel toe cap.
Performance Impacts of Tailored Surface Geometry in Li-Ion Battery Cathodes
Authors: Nelson George J.
Published: April 2014

Analytical models developed to investigate charge transfer in Li-ion battery cathodes reveal distinct transport regimes where performance may be limited by either microstructural surface characteristics or solid phase geometry. For several cathode materials, particularly those employing conductive additives, surface characteristics are expected to drive these performance limitations. For such electrodes gains in performance may be achieved by modifying surface geometry to increase surface area. However, added surface area may present a diminishing return if complex structures restrict access to electrochemically active interfaces. A series of parametric studies has been performed to better ascertain the merits of complex, tailored surfaces in Li-ion battery cathodes. The interaction between lithium transport and surface geometry is explored using a finite element model in which complex surfaces are simulated with fractal structures. Analysis of transport in these controlled structures permits assessment of scaling behavior related to surface complexity and provides insight into trade-offs in tailoring particle surface geometry.
Application of Fourier-Galerkin Method to Volume Averaging Theory Based Model of Heat Sinks
Authors: Sbutega Krsto , Catton Ivan
Published: April 2014

Efficient analysis of heat sink performance is a crucial step in the optimization process of such devices. Accurate analysis of these complex geometric systems with CFD and FE methods requires fine meshes, which imply significant computational time. In this study, Volume Averaging Theory (VAT) is rigorously applied to obtain a geometrically simplified but physically accurate model for any periodic heat sink geometry. The governing equations are averaged over a Representative Averaging Volume (REV) to obtain a set of integro-differential equations. Some information about lower level phenomena is lost in every averaging process and a closure scheme is required to model these behaviors. Experimental data for friction factor and Nusselt number in an REV is used to close the set of PDEs. This mathematical process replaces the complex geometry of the heat sink with a fictitious continuous medium and smoothens the quantities of interest throughout the system. These system features allow the use of a global Fourier-Galerkin method to efficiently solve the resulting equations and accurately predict the performance of the system. The effectiveness of the method is proven by applying it to model thermal behavior for laminar flow over an air-cooled pin-fin heat sink and a water-cooled micro-channel heat sink. The convergence in the Nusselt number in the case of constant heat flux is found to be quadratic with respect to the number of basis functions. The accuracy of the method is validated by comparing the numerical results obtained to existing experimental data. The maximum difference between the predicted Nusselt number and the experimental measurements is found to be only 4% for both cases.
Wall Effect on Separated Flow Around an Inclined Flat Plate at High Incidence
Authors: Lan Chuanjin , Jia Laibing , Li Zhen , Ma Yanbao
Published: April 2014

The flow around bluff bodies has received a great deal of attention due to its practical importance in engineering and scientific relevance in fluid mechanics. The largely separated turbulent flow can be triggered by an inclined flat plate with sharp leading and trailing edge and the presence of wall can alternate the flow structures greatly. This paper applied the Unsteady Reynolds-averaged Navier-Stokes (URANS) model to simulate the vortex shedding phenomenon over the inclined flat plate for a Reynolds number Re = 20 000 with different angle of attack α and gap ratio D/L, the ratio of the distance from the plate to the wall (D) to the plate length (L). Vortex generation from the leading and trailing edge was captured clearly and the transportation and development of vortex structures were shown for different parameters. The smaller the gap ratio is, the more the flow characteristics are affected by the wall presence. The integral quantities, such as lift and drag coefficients show different peak values for different angle of attack.
Experimental Investigation and Numerical Optimization of Key Factors Affecting the Programming Efficacy of Passive UHF RFID Tags
Authors: Lum Kassy M. , Proffitt Donnie , Whitney Ann , Parker Johné M.
Published: April 2014

Radio Frequency Identification (RFID) is a disruptive technology that uses radio waves to uniquely identify objects. As such, it has the potential to bring significant benefits to numerous government and private sector initiatives. However, significant technical challenges remain. A key area of study is in system performance: while the major hardware components in an RFID system (i.e., tags, readers and middleware) have been and continue to be studied extensively, there has been little research, comparatively, in characterizing RFID system performance.

The research presented in this paper was inspired, in part, by a laser printer RFID solution; i.e., one in which the printer simultaneously prints and programs ultra-high frequency (UHF) tags embedded in print media. In this paper, we have conducted a detailed experimental investigation of the primary factors influencing the performance of RFID systems similar to the print solution. This study aims to provide a systematic experimental process for investigating key factors — e.g., the air gap between reader antenna and tag, in-plane orientation of the tag with respect to the reader antenna, and power level output of the reader — which affect the programmability of UHF RFID tags. Results provide a baseline evaluation of the functionality of RFID systems of similar designs and provide a basis for a detailed exploration of the primary factors which affect RFID UHF passive tag dynamic programming capabilities.

By understanding which factors significantly affect the readability and programming of RFID tags, this research suggests optimal designs for system functionality and provides data needed in order to advance such designs. Additionally, a key obstacle for RFID implementation is tag selection. Effectively matching tags to applications requires numerous economic and technical considerations; these considerations generate different implementation constraints. This paper lays the foundation for a multi-objective optimization algorithm to help determine optimal tag selection for a given application, based upon tag performance and cost.
Numerical Analysis of the Internal Fuel Processing in Solid Oxide Fuel Cells
Authors: De La Pena-Cortes Ernesto , Elizalde-Blancas Francisco , Hernandez-Guerrero Abel , Gallegos-Munoz Armando , Belman-Flores Juan M.
Published: April 2014

The high operating temperature of a SOFC (solid oxide fuel cell) has several consequences, from which the most important one is the possibility to feed the cell directly with unprocessed fuels. This eliminates the need for expensive external fuel reformers that hinder the cell from achieving a greater overall efficiency when coupled into a power generation system. Direct internal reforming (DIR) takes place directly on the anode of a SOFC by harnessing the available Nickel catalyst on its surface to process the incoming fuel. In this study a three dimensional steady state computational fluid dynamics model is implemented in a planar DIR SOFC to compare the overall cell performance operating on biogas, and coal syngas. Since chemical kinetics plays a significant role in the model accuracy, the present work also focuses on comparing three different chemical reaction mechanisms for the internal reforming process. These include a detailed heterogeneous mechanism consisting of 42 elementary reactions, a global homogeneous catalyzed mechanism, and a Langmuir-Hinshelwood based mechanism. The former includes autothermal reforming, steam reforming and water gas shift reaction effects, the latter two include steam reforming, and water gas shift reaction effects. The analysis yields detailed information about the cell, including polarization curves that help to assess the cell performance for each fuel. Meanwhile the chemical kinetics comparison amongst the analyzed mechanisms helps in establishing the best compromise between the accuracy of the model, and the computational resources devoted for the calculation.
Reducing Parkinsonian Hand Tremor With a Novel Dynamic Eating Utensil
Authors: Doughty Timothy , Heintz Jordan , Ishii Melissa
Published: April 2014

The work presented here details the modeling, fabrication, testing, and analysis of a dynamic eating utensil designed to reduce hand tremors in subjects with Parkinson’s disease. Most of the current work addressing this problem has been invasive, using medicine or electrical brain stimulation for example. Here, an analysis is presented on the nature of the tremor. This is then used to develop a multi degree-of-freedom analytic model for the forearm/wrist/utensil system. Experiments were performed to identify model form and parameters and theory is presented which allowed for optimized system design. A physical model of the hand/wrist system was developed for testing utensil prototypes in controlled experiment. Ultimately iterative human subject testing validated the design decisions, providing both hard data and survey results to shape the final product. In addition to general performance, special consideration is given to the engineering design parameters and those established by the candidates for ease of use. Specifically, the device presented here outperforms its predecessors in cost, manufacturability, and usability. Additionally, an option for easy user tuning makes the device appropriate for a large host of tremor sufferers. Quantitative and qualitative results indicating the overall effectiveness are presented with the design.
Ice Build-Up Modeling and Performance Analysis of the Customized External-Melt Ice Thermal Energy Storage in the Philippines
Authors: Bongat Ruben A. , Berana Menandro S.
Published: April 2014

This paper elucidates the mathematical modeling of ice build-up, analysis of performance and projected economic impact of a custom-designed external-melt ice thermal energy storage (TES) that was constructed in the Philippines. Custom-designed TES evaporator coil at compressor-aided, partial storage mode with maximum design ice thickness of 2.95 in (74.93 mm) was used for the TES facility with computed maximum cooling demand of 326.2 TR (1,147 kW).

The model was developed for ice formation rates based on relevant and validated researches. The governing equations for freezing were formed to solve for the weight of water converted to ice and prevailing TES bulk water temperature. All the thermophysical properties of ice expressed as a function of bulk ice temperature with correlated compressor capacity based on actual refrigeration system operating parameters was used.

Performance and cost analyses showed that the custom-designed TES cooling coil requires an increase in initial investment by about 14.26% compared to conventional water chiller of similar capacity by only considering the addition of TES tank, excluding electrical and piping requirements of the chiller and TES systems. Benefits from time-of-use (TOU) rates, wherein electricity is cheaper at night, and coefficient of performance (COP) improvement due to lower ambient temperature at night translate to 31.88% internal rate of return (IRR) at 5-year cash flow or simple payback period of 2.55 years.
Sensorless Selective Catalytic Reduction Using Artificial Neural Networks for Emissions Prediction With Fuzzy Logic Control
Authors: Meierjurgen Kenneth , Harries Brian , Compere Marc , Tang Yan
Published: April 2014

The transportation industry is a major contributor to the increase of greenhouse gasses present in the atmosphere. With the number of automobiles increasing every year, the U.S. government has implemented several regulations to reduce the environmental impact of the transportation industry. The most recent regulations increase the Corporate Average Fuel Economy (CAFÉ) to over 50mpg by 2025. These increased fuel economy standards will save consumers money, reduce dependence on foreign oil and cut GHG emissions in half (1). In order to comply with these regulations and reduce GHG emissions, automakers are improving powertrain efficiency and diversifying their fuel sources. One way automakers are improving fleet fuel economy is by offering more efficient Compression Iginition (CI) engines. Compression ignition engines can have a 10% improvement in peak efficiency over a Spark Ignition (SI) Engine. Although CI engines have higher efficiencies, they also have higher Nitrous Oxide (NOx) emissions. One of the most effective methods for reducing NOx emissions is a Selective Catalytic Reduction (SCR) system. Current methods for reducing NOx emissions using SCR rely on two NOx sensors for close loop control. These sensors add substantial costs to the production exhaust after treatment systems. This paper presents an intelligent control technique to achieve accurate prediction of NOx emissions and closed loop control without the use of expensive on board sensors. Simulation models were created to validate two artificial neural networks that aim to replace the upstream and downstream NOx sensors. The upstream neural network was trained using dynamometer data from a General Motors 1.3l turbo diesel engine. This neural network represented NOx emissions as a function of engine speed and throttle position. The downstream ANN was created using a nonlinear statespace plant model that simulates the catalyst NOx and nh3 reaction. To control the nh3 injection into the catalyst, a Fuzzy Logic Controller (FLC) was implemented. The FLC controller had two inputs: the error function calculated from the output NOx and a predetermined NOx target as well as the predicted surface coverage from the nh3 reaction. The results from steady state and drive cycle simulations are shown. The work presented in this paper serves as a proof of concept for the sensorless SCR system that was developed as part of ERAU’s entry in EcoCAR2: Plugging Into the Future. The simulations were conducted as part of year 1 of the EcoCAR2 competition and will be further developed during years 2 and 3 on ERAU’s Series Plug-in Hybrid Electric Vehicle.
Operating Strain Mode Identification Using Acceleration Measurements
Authors: Gevinski Jakerson R. , Pederiva Robson
Published: April 2014

The identification of strain critical regions on machinery and equipment, under operating conditions, can be accomplished by knowing the operating strain modes. Operating strain modes are interpreted as a dynamic strain distribution of the structure at a specific time or frequency. Strain measurements are conventionally obtained by strain gauge techniques. However, strain measurements with conventional strain gauges are not always possible, and the gauges are not reusable and cannot be moved from point to point when they have been attached to structures. In this paper, a post-processing technique based on Operating Deflection Shapes (ODS) is evaluated with an experimental test. Operational strain modes of an aluminum plate were identified from accelerations measured using tri-axial accelerometer. The operating modes were analyzed at frequencies close to the plate’s natural frequency, previously known by numerical simulation, in the frequency range 0–1000 Hz. The plate was excited with random white noise signal. We used the finite element method in the displacement to strain transformation. Operational modes were compared with simulated modes, which were obtained by modal superposition. The comparisons showed consistency between experimentally and numerically identified modes. Regions of greatest strain could be identified graphically in the color map regarding the minimum and maximum strain.
Rectification of Piezoelectric Dynamometer Force Signals During Low Frequency Vibration Assisted Drilling
Authors: Sadek A. , Meshreki M. , Attia M. H.
Published: April 2014

In vibration assisted drilling (VAD), a controlled harmonic motion is superimposed over the principal drilling feed motion in order to create an intermittent cutting state, which reduces cutting forces and temperatures, facilitates chip removal, and increases the possibility for dry machining. However, accurate force measurements during VAD operations has been a challenge especially in systems, where the force transducer is part of the vibrating mass mounted on the shaker head, due to the dynamic force errors. Conventional signal filtering and compensation techniques were found to be not applicable for attenuating undesirable VAD dynamic force components, which exist in the measured force signals at the same frequency of superimposed modulation. This research work presents a corrective dynamic model that rectifies the erroneous VAD tangential and axial force signals measured by a commercial piezoelectric dynamometer mounted on electro-magnetic shakers for the low frequency/high amplitude (LF/HA) regime. An experimental modal analysis in tangential and axial directions was conducted in order to define the transfer function of a multiple degrees of freedom VAD system mounted on a vibrating base (shaker). The rectified force is then obtained by plugging the relative motion between the dynamometer base and face measured during cutting into the system transfer function. The predicted rectified force components showed very high conformance with known impact and sinusoidal excitation forces used for validation. Moreover, the developed corrective model was capable of predicting some features in the VAD force signals that were not fully captured in the measured force signals during cutting.
Energy Benchmarking of Water and Wastewater Treatment, Distribution and Collection: A Case Study of Austin Water Utility
Authors: Kjellsson Jill B. , Greene David , Bhattarai Raj , Webber Michael E.
Published: April 2014

Nationally, 4% of electricity usage goes towards moving and treating water and wastewater. The energy intensity of the water and wastewater utility sector is affected by many factors including water source, water quality, and the distance and elevation that water must be transported. Furthermore, energy accounts for 10% or more of a utility’s total operating cost, suggesting that energy savings can account for significant cost savings. Better knowledge of where and when energy is used could support strategic energy interventions and reveal opportunities for efficiency. Accordingly, this investigation quantifies energy intensity by process and type, including electricity and natural gas, and explores the time-varying nature of electric energy consumption for potable water distribution using the Austin Water Utility (AWU) in Austin, Texas as a case study. This research found that most of energy consumed by the AWU is for pumping throughout the distribution network (57%) and at lift stations (10%) while potable water treatment accounts for the least (5%). Though the focus is site specific, the methodology shown herein can be applied to other utilities with sufficient data.
Utilizing X-Ray Computed Tomography in Spray Nozzle Analysis
Authors: Eichner Daniel J.
Published: April 2014

Characterizing the near-nozzle region of liquid sprays is a challenge for spray system designers due to the lack of optical accessibility in this dense region of the spray using traditional imaging techniques. A novel diagnostic technique, utilizing standard medical X-ray computed tomography equipment, is developed to investigate the time-averaged mass distribution of the liquid phase of the spray within 50 diameters downstream of the nozzle exit. Reconstructed images provide the three-dimensional concentration of the liquid phase of the spray. Analysis of several iodine-based liquids was conducted based on physical properties and non-dimensional parameters. To compare a general procedural approach for obtaining the three-dimensional concentration field from an X-ray CT system, a traditional optical analysis was conducted using Mie Scattering and Shadowgraphy. Results for a full-cone pressure swirl atomizer with an orifice of 0.79 mm are presented for both water and Povidone Iodide. Qualitative and quantitative results gave insight into the spray cone angle, atomization of the spray, and the droplet size and velocity distribution 50 diameters downstream. The water (Re ≈ 20,000) atomizes further upstream than the Povidone Iodide (Re ≈ 6,100) with a larger spray cone angle. The images obtained from the traditional optical techniques were qualitatively compared to the new diagnostic technique. The three dimensional mass distribution of Hypaque from a 0.79 mm nozzle has a number of similarities with the water spray, measured with an isotropic spatial resolution of 200 μm and noise per voxel less than 0.02 g/cm3.
Controlling Lattice Thermal Conductivity via Coherent Phonon Manipulation
Authors: Zhang Yan , Wang Yaguo , McGaughey Alan J. H.
Published: April 2014

Controlling thermal conductivity of materials is very important in various applications, such as thermal management and energy conversion. We have been utilizing femtosecond phonon spectroscopy to excite and detect coherent phonons in various materials. However, the impact of coherent phonons to overall heat transport is still unknown. In this paper, we developed a small perturbation model in molecular dynamics (MD) to simulate coherent phonons and investigate the effect on thermal conductivity in bismuth telluride. The phonon frequency and lifetime predicted by our model agree very well with experimental results. It is found that at very low temperature, the lattice thermal conductivity, predicted by quasi-equilibrium Green-Kubo method, can be greatly enhanced upon coherent phonon generation. Our results suggest that it is possible to control lattice thermal conductivity effectively via manipulating coherent phonons.
Microstructural Effects on Thermal Conductivity of Uranium Oxide: A 3D Multi-Physics Simulation
Authors: Lim Harn Chyi , Rudman Karin , Krishnan Kapil , McDonald Robert , Peralta Pedro , Dickerson Patricia , Byler Darrin , Stanek Chris , McClellan Kenneth J.
Published: April 2014

Transport mechanisms, such as mass and heat transfer, are critical to the efficiency and the reliability of nuclear fuels such as uranium oxide. These properties can be significantly affected by the microstructure of the material. This paper looks into the effects of grain boundary (GB) Kapitza resistance on the overall heat conductivity of UO2 using a 3-D finite element model with microstructurally explicit information. The model developed is created with a 3-D reconstruction of the microstructure of depleted uranium samples performed using serial sectioning techniques with Focused Ion Beam (FIB) and Electron Backscattering Diffraction (EBSD). The model treats grain bulks, GBs and triple junctions using elements of different dimensionalities, and it is thus capable of incorporating information of all three entities in one model while keeping a manageable computational cost. Furthermore, the properties of these microstructural entities are characterized by misorientation angles and Coincident Site Lattice (CSL) models, which provide a framework to assign spatially dependent thermal and mass transfer properties based on the location and connectivity of these entities in actual microstructures. Coupling between heat transfer and mass transfer of fission products is also taken into account in the study, to make it a multi-physics model capable of following the evolution of thermal performance as fission products are produced. These simulations can provide input and insight into the fuel pellet behaviors at the initial stage of power generation when burnups are low.
Poly-Disperse Droplet Evaporation Model — Comparison With Experimental Results
Authors: Protheroe Michael D. , Al-Jumaily Ahmed M. , Nates Roy J.
Published: April 2014

Experimental data for the evaporation of micron-size, poly-disperse water droplets into air has been generated in order to validate a theoretical poly-disperse droplet evaporation model. The model considers air and droplets flowing along a tube and predicts changes in droplet sizes and temperatures as well as air temperature and humidity as functions of distance along the tube. There are small discrepancies between experimental and model results which can be explained in terms of the lack of mixing between the droplets and air stream and also possible settling of the larger droplets in the experimental apparatus.
Performance of Constant Power Operated Swash Plate Axial Piston Pumps With Fuzzy Logic Controllers
Authors: Anis Yasser H. , Kassem Saad A.
Published: April 2014

In this paper, simulation of the step response of electro hydromechanically controlled constant power regulated swash plate axial piston pumps with conical cylinder blocks has been carried out when a new fuzzy logic controller (FLC) is proposed to replace the PD controller in current use. The theoretically deduced performance shows that the proposed FLC renders better performance when compared to both the PD controller and a previously proposed FLC. The effects of the control valve supply pressure, valve port width, and control piston leakage coefficient on the pump step response has been investigated. Results show that the proposed FLC renders better dynamic performance, when compared with the previously proposed FLC and the PD controller, at all practical values of the investigated three parameters.
Design of a Single-Stage Centrifugal Compressor and Numerical Investigation of Simultaneous Adjustment of Inlet Guide Vanes and Diffuser Vanes
Authors: Ni Qifeng , Hou Anping , Tian Ye , Xu Quanyong , Liu Enlai
Published: April 2014

A single stage centrifugal compressor has been designed for industrial use. Adjustable Inlet Guide Vanes (IGVs) and vaned diffusers were equipped to meet the requirement of large flow range, high efficiency and constant shaft speed. Both numerical calculations and experiments were implemented to get the performance of this new designed centrifugal compressor. The influence of adjustable IGVs and vaned diffusers on the stage performance characteristic was examined by numerical method. It is shown that numerical simulation results are close to the measured results and predict the stall limit well. The new centrifugal compressor has a comparatively high efficiency and wide operating range. Moreover, unilateral adjustment of either IGV pre-whirl angle or vaned diffuser stagger angle enables an increase in stable operating range opposed to the stage configuration with no adjustment. The combination of simultaneous adjustment of the IGVs and diffuser vanes can not only provide even wider flow range but also keep high efficiency. The identical working point can be operated at different IGV pre-whirl angles and diffuser stagger angles, hence the optimum adjustment schedule for the specified operating line was dug up to obtain an optimum efficiency. Detailed flow field analysis was performed to validated the suitable simultaneous adjustment combinations.
Stability and Bifurcations in Three-Dimensional Analysis of Axially Moving Beams
Authors: Ghayesh Mergen H. , Amabili Marco , Farokhi Hamed
Published: April 2014

The geometrically nonlinear dynamics of a three-dimensional axially moving beam is investigated numerically for both sub and supercritical regimes. Hamilton’s principle is employed to derive the equations of motion for in-plane and out-of plane displacements. The Galerkin scheme is applied to the nonlinear partial differential equations of motion yielding a set of second-order nonlinear ordinary differential equations with coupled terms. The pseudo-arclength continuation technique is employed to solve the discretized equations numerically so as to obtain the nonlinear resonant responses; direct time integration is conducted to obtain the bifurcation diagrams of the system. The results are presented in the form of the frequency-response curves, bifurcation diagrams, time histories, phase-plane portraits, and fast Fourier transforms for different sets of system parameters.
Transient Exergy Analysis for Solar Desalination Processes
Authors: Kowalski Gregory J. , Modaresifar Masoud , Zenouzi Mansour
Published: April 2014

An investigation of the transient entropy property term, entropy storage, for a desalination device was performed. It was illustrated that entropy production rates provide a means of comparing alternative energy solutions and a measure of their sustainability. To satisfy these objectives one needs accurate calculation of entropy production rates. It was confirmed that neglecting the exergy storage term is not a valid approximation for the hourly and daily averaged values of the second law analysis. For a solar desalination system neglecting the exergy storage terms introduced a maximum difference in the entropy production rate of 7.4% and a difference of 7.3% in the daily average. In the solar desalination process with heat recovery the second law performance is greater than that for the reverse osmosis process, the chief competitor, when the exergy storage terms are correctly included in the analysis. The results demonstrate that for variable energy sources such as renewable energy systems, the second law analysis provides a measure of the sustainability of competing system and that the exergy storage terms should be included in the analysis.
Experimental Characterization of Adsorption and Transport Properties for Advanced Thermo-Adsorptive Batteries
Authors: Kim Hyunho , Yang Sungwoo , Narayanan Shankar , McKay Ian , Wang Evelyn N.
Published: April 2014

Thermal energy storage has received significant interest for delivering both heating and cooling in electric vehicles, to minimize the use of the on-board electric batteries for heating, ventilation and air-conditioning (HVAC). An advanced thermo-adsorptive battery (ATB) is currently being developed, to provide both heating and cooling for an electric vehicle. We present a detailed thermophysical and physicochemical characterization of adsorptive materials for the development of the ATB. We discuss the feasibility of using contemporary adsorptive materials, such as zeolite 13X, by carrying out a detailed experimental characterization. In this study, zeolite 13X is combined with aluminum hydroxide (Al(OH)3) as a binder to improve the thermal conductivity. We also investigate the effect of densification on the overall transport characteristics of the adsorbent-binder composite material. Accordingly, the effective thermal conductivity, surface area, adsorption capacity and surface chemistry were characterized using the laser flash technique, surface sorption analyzer, thermogravimetric analyzer, and x-ray scattering technique. Thermal conductivity predictions of both zeolite 13X and its combination with the binder were made with existing conductivity models. Thermal conductivity in excess of 0.4 W/mK was achieved with the addition of 6.4 wt.% of Al(OH)3. However, a 10.6 % decrease in adsorption capacity was also observed. The experimental characterization presented herein is an essential step towards the development of the proposed ATB for next-generation electric vehicles.
An Investigation of the Effect of Inclination on Critical Heat Flux of PF-5060 Dielectric Liquid on Microporous Copper Surfaces
Authors: Ali Amir F. , El-Genk Mohamed S.
Published: April 2014

Pool boiling experiments investigated the effect of inclination angle on the Critical Heat Flux (CHF) for saturation boiling of PF-5060 dielectric liquid on MicroPorous Copper (MPC) surfaces of different thicknesses (80 to 230 μm). The morphology of the surfaces, deposited using electrochemical processes, vary with the thickness, and hence CHF. The inclination angles investigated are 0° (upward facing), 60°, 90° (vertical), 120°, 150°, 160°, 170° and 180° (downward facing). CHF decreases with decreasing MPC thickness and/or increasing inclination angle. The CHF values in the upward facing orientation are 39%–67% higher than on smooth, polished Cu. For all MPC surfaces, CHF values in the downward facing orientation are ∼ 28% of those in the upward facing orientation (0°). The developed CHF correlation accounts for the effects of MPC thickness and inclination angle and is in agreement with experimental data to within ± 8%.
Effects of Surface Roughness and Inclination Angle on Nucleate Boiling of PF-5060 Dielectric Liquid on Copper
Authors: El-Genk Mohamed S. , Suszko Arthur , Ali Amir F.
Published: April 2014

Saturation pool boiling experiments of PF-5060 dielectric liquid are performed using eleven different Cu surfaces with average roughness, Ra = 0.21 to 1.79 μm, at inclination angle, θ, from 0° (upward facing) to 180° (downward facing). Nucleate boiling heat transfer coefficient, hNB, increases with increasing surface roughness and with decreasing inclination angle. The measured enhancements in hNB with increased surface roughness are in excess of 36%. In the upward facing orientation, the experimental values of hNB are correlated in terms of the surface heat flux in the experiments, q, as: hNB = A qB. The coefficient “A” increases from ∼0.14 to 0.23, while the exponent “B” decreases from 0.76 to 0.69 as Ra increases from 0.21 to 1.79 μm.
A Numerical Analysis of the Solar Panel Support Structure on the Weak Ground
Authors: Joo Kang-Woo , Kim Jun Young , Park Kyu Tae , Kim Kwang-Sun
Published: April 2014

The regulations for environmental issues on the use of fossil energy and the upsurge of the power demand due to the improving standard of living worldwide increasingly require the development of renewable energy sources. In particular, developing countries suffer from severe lack of energy because they do not have technical ability for large-capacity generation facilities, such as thermal or nuclear power generation plants, and financial capacity to procure the resources. Therefore, most countries are trying to develop the renewable energy sources, especially the solar generation facilities. In the solar power generation system, the structural stability of the support unit that supports the large-area solar panel is essential to ensure the high generation efficiency and the long life of the system. According to the international standards and industry practice, the solar power system must be stable against the 120 km/h wind and its life must be 20 years or longer. The solar panel for the solar generation system are made by combining ten to several tens of solar modules depending on the scale of the system. This generates a load of at least 250 kg, and if the aerodynamic force due to the strong wind is additionally applied, the severe ground settlement of the support unit on the weak ground may damage the system. In this study, the structure of the solar power system, which can operate stably in the areas with weak ground, such as Laos and Vietnam, is proposed. Diverse load distributions and structure deformations were calculated via numerical analysis, and the typical ground characteristics of the subject areas were considered to determine the structure that minimizes the settlement.
The Effect of Arm Position as a Comparison Between Gender During Single-Leg Landings
Authors: Tse Chi-Yin , Vaziri Ashkan , Canavan Paul K. , Goebel Ruben , Nayeb-Hashemi Hamid
Published: April 2014

Increased knee valgus loading has been previously identified as a possible risk factor for non-contact anterior cruciate ligament (ACL) injury. Arm position during landing may affect the risk of injury by increasing the knee valgus load. The goal of this study was to examine the kinematics and kinetics of the knee joint during single-leg drop landings from platform heights that was subject specific. Ten subjects (5 female, 5 male) were selected to participate in this single-leg landing study. No significant difference in knee kinematics was noted between arm positions, or gender. Significant difference (p < 0.05) was noted in the varus/valgus knee angle at initial contact (VVIC) when comparing the 60% vertical max jump percentage (%VJMax) to the 80% VJMax and 100% VJMax.
Investigation of Using Dispersed Particle and Branching Heat Exchnager in Medium Temperature Thermal Energy Storage System to Achieve Maximum Utilization of Solar Power
Authors: Hasib A. M. M. G. , Rayegan Rambod , Tao Yong X.
Published: April 2014

Maximum utilization of solar energy is very critical to achieve, because a significant portion of solar energy is lost in the form of heat. In that case Thermal Energy Storage (TES) can play a significant role by capturing the energy in the form of heat and later on can be used as a backup source of energy for utilizing it in critical time. On the other side, from the view point of conservation of energy, energy cannot be created or destroyed, but surprisingly a significant amount of energy cannot be utilized due to the instantaneous nature of conventional power generation. So storing Energy is the most unique idea that can act as a strong backup for the instantaneous nature of power generation as it not only adds up to the power generation capacity but also serves to be the most reliable medium of supplying power when the energy demand is at peak. In the authors’ previous work a phase change material (molten solar salt comprised of 60% NaNO3+40%KNO3) and a system design for thermal energy storage (TES) system integrated with a solar Organic Rankine Cycle (ORC) has been proposed. The associated research problems investigated for phase change material (PCM) are the low thermal conductivity and low rate of heat transfer from heat transfer fluid to PCM. In this study a detailed numerical modeling of the proposed design using MATLAB code and the relevant calculation and results are discussed. The numerical model is based on 1-D finite difference explicit technique using the fixed grid enthalpy method. To overcome the research problem highly conductive nano-particle graphite is used to enhance the effective thermal conductivity of the PCM material in theoretical calculation. In the later part of the study results from the numerical computation have been utilized to demonstrate a comparison between a conventional heating system (with a simple single tube as a heat exchanger) and a branching heat exchanger in PCM thermal energy storage system using NTU-Effectiveness method. The comparison results show a significant amount of improvement using branching network and mixing nano-particle in terms of heat transfer, thermal conductivity enhancement, charging time minimization and pressure drop decrease. The results of this study can convince us that the proposed medium temperature TES system coupled with solar ORC can be a stepping-stone for energy efficient and sustainable future in small-scale power generation as the system proves to be better in terms of enhanced heat transfer, increased thermal conductivity and overall sustainability.
Simulation of Vertical Axis Wind Turbines With Variable Pitch Foils
Authors: Woods L. Damon , Gardner John F. , Myers Kurt S.
Published: April 2014

A dynamic computer model of a turbine was developed in MATLAB in order to study the behavior of vertical axis wind turbines (VAWTs) with variable pitch (articulating) foils. The simulation results corroborated the findings of several empirical studies on VAWTs. The model was used to analyze theories of pitch articulation and to inform the discussion on turbine design. Simulations of various models showed that pitch articulation allowed Darrieus-style vertical axis wind turbines to start from rest. Once in motion, the rotor was found to accelerate rapidly to very high rotational velocities. The simulations revealed a plateau region of high efficiency for small-scale Darrieus-style VAWTs with symmetric airfoils at tip speed ratios in the range of 3 to 4 and demonstrated the advantages of using a dynamic generator load.
Numerical Investigation of Aerodynamic Drag on Vacuum Tube High Speed Train
Authors: Bibin Sreeja , Mukherjea Sujay Kumar
Published: April 2014

This work involves numerical simulations based on finite volume method to study the effects of different factors on the aerodynamic drag on a vacuum tube train running at subsonic and transonic speeds in a partially vacuum tunnel. Investigation includes the study of the effects of the shapes of head, tail, vacuum pressure and also blockage ratio of the tunnel on aerodynamic drag on a high speed train. The simulation is performed by using fluent software. Two dimensional, axisymmetric, compressible Navier-Stokes equations were solved by using k-ε turbulent modeling. Five different blockage ratios at five different speeds of the train have been considered. The simulated results show that, the blockage ratio and different working vacuum pressure significantly affects the aerodynamic drag of the train in a tunnel. Investigations with respect to different shapes of the head as well as that of the tail indicate the optimum shape for minimum drag.
On the Physics of Conversion of Longitudinal Elastic Waves Into Extended Vibrations in a Suspended Aluminum Rod
Authors: Georgiou Ioannis T.
Published: April 2014

This work concerns a two stage decomposition analysis of a dynamics phenomenon due to reflection of longitudinal pulse elastic waves in long elastic rods. Elastic pulse waves are induced by impacting a miniature modal hammer at one of its free ends whereas its dynamics is recorded by a high performance piezoelectric sensor at the other end. An underlining characteristic time scale leads to a natural decomposition of experimental time series of wave acceleration into a sequence of time frames. The signals are viewed as a sequence of time frames and thus are analyzed globally and locally by further decomposing them into their intrinsic Proper Orthogonal Decomposition Modes (POD) or Principal Component Analysis (PCA) modes. It is found that experimental signals of acceleration during propagation of elastic pulse waves are governed by a small number of POD modes; one of the modes is dominant. It is conjectured that these intrinsic modes of the time frame-arranged signals represent physical modes of pulse wave propagation. The introduced method of the two-stage decomposition analysis is potentially useful for data-driven analysis in wave propagation-based damage detection.