bluuebunny/crossref_metadata_2025_split huggingface dataset:
Net Energy and CO2 Emissions Analysis of Using MRF Residue as Solid Recovered Fuel at Coal Fired Power Plants
Authors: Breckel Alex C. , Fyffe John R. , Webber Michael E. 
Published: October 2013

According to the waste management hierarchy published by the U.S. EPA, waste reduction and reuse are the most preferred modes of waste management, followed by recycling, energy recovery and lastly disposal. As many communities in the U.S. work towards sustainable waste management practices, recycling tends to be a cost-effective and common solution for handling municipal solid waste. With the introduction of single-stream recycling and automated materials recovery facilities (MRFs), where commingled recyclables are sorted into various commodity streams for sale to recycling facilities, recycling rates have steadily climbed in recent years. Despite increasing total recycling rates, contamination and diminishing returns for higher recovery ratios causes MRFs to landfill 5–25% of the incoming recycling stream as residue. This residue stream is composed primarily of plastics and fiber, both of which have high energy content that could be recovered instead of buried in a landfill. Plastics in particular are reported to have heat contents similar to fossil fuels, making energy recovery a viable end-of-life pathway. Sorting, shredding and densifying the residue stream to form solid recovered fuel (SRF) pellets for use as an alternative fuel yields energy recovery, displaced fossil fuels and landfill avoidance, moving more disposed refuse up the waste management hierarchy. Previous studies have shown that plastic, paper, and plastic-paper mixes are well suited for conversion to SRF and combustion for energy production. However, these studies focused on relatively homogenous and predictable material streams. MRF residue is not homogenous and has only a moderate degree of predictability, and thus poses several technical challenges for conversion to SRF and for straightforward energy and emissions analysis.
This research seeks to understand the energetic and environmental tradeoffs associated with converting MRF residue into SRF for co-firing in pulverized coal power plants. A technical analysis is presented that compares a residue-to-SRF scenario to a residue-to-landfill scenario to estimate non-obvious energy and emissions tradeoffs associated with this alternative end-of-life scenario for MRF residue. Sensitivity to key assumptions was analyzed by considering facility proximity, landfill gas capture efficiency, conversion ratio of residue to SRF and the mass of residue used.
The results of this study indicate that the use of MRF residue derived SRF in coal fired steam-electricity power plants realizes meaningful reductions of emissions, primary energy consumption, coal use and landfill deposition.
Circuit Development of Piezoelectric Energy Harvesting Device for Recharging Solid-State Batteries
Authors: Li Yuejuan , Cheng Marvin H. , Bakhoum Ezzat G. 
Published: October 2013

Piezoelectric devices have been widely used as a means of transforming ambient vibrations into electrical energy that can be stored and used to power other devices. This type of power generation devices can provide a convenient alternative to traditional power sources used to operate certain types of sensors/actuators, MEMS devices, and microprocessor units. However, the amount of energy produced by these devices is in many cases far too small to directly power an electrical device. Therefore, much of the research into power harvesting has focused on methods of accumulating the energy until a sufficient amount is present, allowing the intended electronics to be powered.
Due to the tiny amount of harvestable power from a single device, it is critical to collect vibration energy efficiently. Many research groups have developed various methods to operate the harvesting devices at their resonant frequencies for maximal amount of energy. Different techniques of conversion circuits are also investigated for efficient transformation from mechanical vibration to electrical energy. However, efforts have not been made to the analysis of array configuration of energy harvesting elements. Poor combination of piezoelectric elements, such as phase difference, cannot guarantee the increasing amount of harvested energy. To realize a piezoelectric energy-harvesting device with higher volume energy density, the energy conversion efficiencies of different array configurations were investigated. In the present study, various combinations of piezoelectric elements were analyzed to achieve higher volume energy density. A charging circuit for solid-state batteries with planned energy harvesting strategy was also proposed. With the planned harvesting strategy, the required charging time can be estimated. Thus, the applicable applications can be clearly identified.
In this paper, optimal combination of piezoelectric cantilevers and different modes of charging methods were investigated. The results provide a means of choosing the piezoelectric device to be used and estimate the amount of time required to recharge a specific capacity solid-state battery.
The Effect of Subtalar Arthrodesis Alignment on Ankle Biomechanics
Authors: Jastifer James R. , Gustafson Peter A. , Gorman Robert R. 
Published: October 2013

Background: The position, axis, and control of each lower extremity joint intimately affects adjacent joint function as well as whole limb performance. There is little describing the biomechanics of subtalar arthrodesis and none describing the effect that subtalar arthrodesis position has on ankle biomechanics. The purpose of the current study is to establish this effect on sagittal plane ankle biomechanics.
Methods: A study was performed utilizing a three-dimensional, validated, computational model of the lower extremity. A subtalar arthrodesis was simulated from 20 degrees of varus to 20 degrees of valgus. For each of these subtalar arthrodesis positions, the ankle dorsiflexor and plantarflexor muscles’ fiber force, moment arm, and moments were calculated throughout a physiologic range of motion.
Results: Throughout ankle range of motion, plantarflexion and dorsiflexion strength varies with subtalar arthrodesis position. When the ankle joint is in neutral position, plantarflexion strength is maximized in 10 degrees of subtalar valgus and strength varies by a maximum of 2.6% from the peak 221 Nm. In a similar manner, with the ankle joint in neutral position, dorsiflexion strength is maximized with a subtalar joint arthrodesis in 5 degrees of valgus and strength varies by a maximum of 7.5% from the peak 46.8 Nm. The change in strength is due to affected muscle fiber force generating capacities and muscle moment arms.
Conclusion: The clinical significance of this study is that subtalar arthrodesis in a position of 5–10 degrees subtalar valgus has biomechanical advantage. This supports previous clinical outcome studies and offers biomechanical rationale for their generally favorable outcomes.
Direct Measurement of the Local Current Density Under Land-Channel Areas With Partially-Catalyzed MEAs
Authors: Jia Shan , Liu Hongtan 
Published: October 2013

In a PEM fuel cell, local current density can vary drastically under the land and channel areas. The non-uniform current density distribution not only affects the overall performance of the fuel cell, but also leads to the local temperature and concentration differentiation on the MEA, which can cause problems such as membrane dehydration and catalyst degradations at certain locations. In order to investigate the local current performance, the objective of this work is to directly measure the local current density variations across the land and channel at the cathode in a PEM fuel cell with partially-catalyzed MEAs.
First, the cathode flow plate is specially designed with a single-serpentine channel structure, and the gas diffusion electrode at cathode side is cut to fit this flow field size (5.0cm×1.3cm). Then five different partially-catalyzed MEAs with 1mm width corresponding to different locations from the middle of the gas channel to the middle of the land area are made. Fuel cells with each of the partially-catalyzed MEAs have been tested and the results provide the lateral current density distribution across the channel and the land areas. In the high cell voltage region, local current density is highest under the center of the land area and decreases toward the center of the channel area; while in the low cell voltage region local current density is highest under the middle of the channel area and decrease toward the center of the land area. Different flow rates are tested at the cathode side of the cell to study their effects on the local current density performance along the land-channel direction. And the results show that the flow rate barely has the effect on the current at the high cell voltage region, while it plays a significant role at the low voltage region due to the mass transport effect.
Exergetic Analysis of an Air Conditioning System by Absorption for Transport Vehicles
Authors: Almeida Antonio Gabriel S. , dos Santos Arthur B. , Torres Ednildo Andrade 
Published: October 2013

A traditional vehicular air conditioning system using vapor compression increases fuel consumption by at least 15%, while provoking a reduction in engine power. Whereas an internal combustion engine converts about 30% of the energy into mechanical energy, about 35% is released in the form of exhaust gas and 25% is dissipated through the cooling system, and approximately 50% of the available fuel energy is released as heat to the environment. This heat could be used by an absorption refrigeration system, which requires a high temperature source to provide the vaporization of the refrigerant and decoupling from the absorbent solution.
The main objective of this paper is to present a thermodynamic evaluation of the use of heat recovery in internal combustion engines, Diesel cycle, to drive an air conditioning absorption refrigerator for vehicles using the pair water-ammonia. An energy and exergy analysis, applying the First and Second Law of Thermodynamics to the systems involved, is developed in a simulator to evaluate the technical feasibility of using this system to weatherize large vehicles. It identifies the points of the system where the highest irreversibility is found, thus enabling the power focused on reducing such losses. By using asimulation, we hope to determine the basis for the assembly of a prototype vehicular air conditioning system by absorption in transport vehicles.
Evaluation of Pulse Jet Mixer Concentration Profiles to Track Slurry Suspension
Authors: Bamberger Judith Ann 
Published: October 2013

A series of tests were conducted to evaluate the mixing performance of pulse jet mixers. A pulse-jet mixing system involves an array of pulse tubes with nozzles directed toward the vessel floor inside the mixing vessel. Fluid is expelled from the pulse tubes during the drive portion of the PJM cycle. Fluid refills into the pulse tubes during the refill portion of the PJM cycle. This cyclical process can be used to mix slurries.
Concentration profiles as a function of location and elevation in the tank were taken during the pulse jet mixer cycle at several radial locations within the mixing vessel: at the center, near the wall, and half-way between the center and the wall. The data are being examined to determine how the time during the cycle affects the solids suspension and settling. Examples will be presented for several particle types, concentrations, and pulse-jet operating conditions.
Experimental Study of Enhanced Steam Generation Through Electrolysis in Glow Discharge Mode
Authors: Sharma Neeraj , Diaz Gerardo , Leal-Quiros Edbertho 
Published: October 2013

Electric discharges through liquids initiate various chemical and physical processes which can be utilized in efficient treatment of waste water and generation of steam. In the present paper, generation of heat in an electrolytic cell operating in glow discharge mode has been studied. It is observed that glow discharge mode constitutes an efficient process for steam generation.
The electric current between the electrodes reduces dramatically in the glow discharge mode and the voltage between the electrodes increases to open circuit voltage. The decrease in current can be explained by decrease in overall electrical conductivity of the system with the formation of a vapor film around the cathode. This vapor film is partially ionized because of the presence of locally high electric field near the cathode. It is this ionization process that results in a visible glow around the cathode and an increased rate of volumetric heat generation.
Development of the New Drafting and Computer Aided Design Standards for Mechanical Engineering Program
Authors: Joo Sung-Hwan 
Published: October 2013

The paper provides the method to develop the drafting and CAD standards for mechanical engineering program based on the systemic approach.
The drafting has been used since the early stage of engineering. Lots of drafting technique has been developed and standardized. Recently, Computer Aided Design (CAD) software has been used widely in academia and industries too. Because of these reasons, every mechanical engineering program offers Drafting and CAD courses to its students. Some programs even have their own Drafting and CAD standards. However, it is not easy to develop the Drafting and CAD standard for whole program. It needs a careful plan to develop the standards. It needs to meet the certain requirements. Those requirements are 1) It needs to meet ASME Y14/ANSI Y14 standard as much as possible, 2) Students should be able to understand the standards and apply the rules to their own drawing and CAD models, 3) Any instructors should be able to give the proper feedback to students about their drawing using the standards, 4) Graduating students should be able to adopt the standard of their company easily.
To meet these requirements, some preliminary work must be done. 1) Understanding of ASME Y14 is needed, 2) Expertise of one or more CAD software packages is required, 3) Students’ level of understanding the ASME Y14 standards needs to be measured, 4) Feedback from industries is required. Each steps of development of Drafting and CAD standards are explained using real example of students work.
Creativity in Multi Objective Problem Solving
Authors: El-Sayed Mohamed E. M. , El-Sayed Jacqueline A. J. 
Published: October 2013

Problem solving is one of the main activities in achieving design and research goal. While problem solving in general is an activity aiming at transforming unacceptable state of reality to acceptable state of reality, problem solving in engineering is usually a means for tackling other activities such as design and research. By breaking down design and research into a set of engineering problem solving activities, the goals of complicated design and research projects can be achieved. For this reason, the transitions from design or research to problem solving in some cases are unidentifiable. The identification of the problem solving activity goals and the transition between the three activities, however, are essentials for creativity and achieving the desired objectives especially when dealing with conflicting objectives and constraints.
In this paper, design, research, and problem solving are distinguished as realization activities performed in different reality domains with different beginning and ending states. These three activities use modeling and simulation as basic elements of mapping between realities to perform analysis and integration. While analysis and simulation are mainly the analytical actions, modeling and integration are mainly the creative actions. With these distinctions, the identification of problem solving activity goals, and transitions between activities, can be easily realized. Also, creativity and dealing with conflicting objectives can be greatly facilitated. To demonstrate these concepts and their implications some illustrative examples are discussed.
Optimization Under Uncertainty of Manifold Microchannel Heat Sinks
Authors: Sarangi Suchismita , Bodla Karthik K. , Garimella Suresh V. , Murthy Jayathi Y. 
Published: October 2013

Conventional microchannel heat sinks provide good heat dissipation capability but are associated with high pressure drop and corresponding pumping power. The use of a manifold system that distributes the flow into the microchannels through multiple, alternating inlet and outlet pairs is investigated here. This manifold arrangement greatly reduces the pressure drop incurred due to the smaller flow paths, while simultaneously increasing the heat transfer coefficient by tripping the thermal boundary layers. A three-dimensional numerical model is developed and validated, to study the effect of various geometric parameters on the performance of the manifold microchannel heat sink.
Apart from a deterministic analysis, a probabilistic optimization study is also performed. In the presence of uncertainties in the geometric and operating parameters of the system, this probabilistic optimization approach yields an optimal design that is also robust and reliable. Uncertainty-based optimization also yields auxiliary information regarding local and global sensitivities and helps identify the input parameters to which outputs are most sensitive. This information can be used to design improved experiments targeted at the most sensitive inputs. Optimization under uncertainty also provides a quantitative estimate of the allowable uncertainty in input parameters for an acceptable uncertainty in the relevant output parameters. The optimal geometric design parameters with uncertainties that maximize heat transfer coefficient while minimizing pressure drop for fixed input conditions are identified for a manifold microchannel heat sink. A comparison between the deterministic and probabilistic optimization results is also presented.
Effect of Fluid Dynamic Parameters on the Performance of a Radial Flow Pressure Exchange Ejector
Authors: Umar Muhammad , Garris Charles A. 
Published: October 2013

The “Pressure exchange” is a novel concept in turbomachinery whereby two fluids, at different energy levels, come in direct contact with each other to transfer energy and momentum between them through non-steady interface pressure forces. The rotating jets of the high pressure primary fluid, often referred to as pseudoblades, resemble solid blades on the impeller of a conventional turbomachine. The low pressure secondary fluid, ahead of the pseudoblades, is pressurized by the action of interface pressure forces.
The current paper seeks to provide an insight into the complex flow phenomena occurring inside the radial flow pressure exchange ejector. This research presents the results of the first successful numerical simulation to explore the effects of primary to secondary total pressure ratio and primary to secondary total temperature ratio on the performance of a radial flow pressure exchange ejector.
Finite Element Modeling and Analysis of Photovoltaic Modules
Authors: Hasan Osama , Arif A. F. M. , Siddiqui M. U. 
Published: October 2013

A Photovoltaic (PV) module consists of layers of different materials constrained together through an encapsulant polymer. During operation, it experiences mechanical and thermal loads due to seasonal and temperature variations, which cause breakage of interconnects owing to fatigue and laminate warpage. This is due to the fact that there is a coefficient of thermal expansion (CTE) mismatch because of the presence of unlike materials within the laminate. Therefore, thermo-mechanical stresses are induced in the module. Glass, being the thickest of all in the module, plays a significant role in the stressing of components. The lifetime of today’s PV module is expected to be 25 years and this period corresponds to the guarantee of the manufacturer. Its high reliability will help it to reach grid parity. But the problem is that it is not convenient to wait and assess its durability. Qualification standards such as ASTM E1171-09 are useful in predicting a module’s failure.
In this work, material of each component of the PV module is characterized and then the implementation of material models is discussed. A Finite-Element (FE) model of 36 cell PV module is developed using 2D layered shell elements in ANSYS. A single temperature cycle of ASTM E1171-09 is simulated after lamination procedure and 24 hour storage at constant temperature. The FE model is validated by simulating an experimental procedure in the literature by determining change of cell gap during the temperature cycle. Finally, parametric studies are performed with respect to lamination thickness.
Influence of Edge-Boundaries on the Cohesive Behaviour of an Adhesive Layer
Authors: Biel Anders , Walander Tomas , Stigh Ulf 
Published: October 2013

In comparison with other adhesives e.g. epoxies, polyurethane adhesives (PUR) are soft. In automotive applications, the thickness of PUR-adhesive layers is between about 2 to 5 mm. Since these adhesives cure by moisture, the width of the joints is limited. Often, the width is only marginally larger than the thickness of the layer.
In numerical FE-simulations it is now common to represent epoxy adhesive layers by cohesive elements. With this model, both stress distribution and fracture can be modelled using mesh sizes that allows for large-scale analyses. Material properties are usually the result from experiments with coupon type specimens, e.g. the double cantilever beam specimen (DCB). With PUR-adhesives this approach is problematic. The adhesive is very flexible and effects from the edge-boundaries cannot be ignored.
In order to study the influence of the edge-boundaries in peel loading, experiments with the DCB-specimens are performed. Specimens with a layer thickness of 3 mm and three different widths between 10.6 mm to 40.6 mm are studied. The PUR-adhesive SikaFlex-UHM is used. All the experiments are performed at a constant loading rate. The cohesive law is measured.
The experimental results show that the maximum peel stress is increasing with an increasing width of the specimen, i.e. when the influences from the edges decrease. When the width increases from 10.6 mm to 40.6 mm, the maximum evaluated peak stress increases from about 5 MPa to about 7 MPa. From visual inspections during the experiments it is conjectured that crack growth starts with voids initiating inside the adhesive. At a critical point, the voids rapidly reach the surface and crack growth starts.