bluuebunny/crossref_metadata_2025 huggingface dataset:
Numerical Modeling and Parametric Assessment of Proppant Flow in Fractured Reservoirs
Authors: Das Kaushik , Basu Debashis , Smart Kevin , Ofoegbu Goodluck
Published: March 2016

Numerical simulation of proppant flow through a single idealized rectangular fracture in a reservoir has been conducted to understand the effect of various physical and operational parameters on proppant placement within a fracture. A three-dimensional Computational Fluid Dynamics model with a Eulerian-Granular (also referred to as Eulerian-Granular or Two-Fluid) model for solid particle transport simulations has been used to study the movement of proppant particles through this idealized single fracture. In the Eulerian-Granular method, the fluid-particle mixture is represented by two-phase interpenetrating continua with the particulate matter treated as a separate continuous phase. This Eulerian-Granular method depends on constitutive relationships to model additional terms for the solid phase. Parametric assessment has been carried out to analyze the influence of proppant size on the proppant settling behavior. In addition, the effects of fracture width and the effect of fluid viscosity have been studied. The simulations resolved the complex particle-particle as well as fluid-particle interactions. Computed results indicate that the proppant settling and fracture filling patterns depend on injected proppant size, with use of larger proppants, resulting in a relatively lower filling fraction. Results also show that lowering the fracturing fluid viscosity helps to disperse proppant particles more uniformly within the fracture. Narrower fractures have more pronounced wall effects that impede proppant movement, resulting in poorly filled fracture volume.
Effect of Reinforcement Type and Extrusion on the Microstructure and Mechanical Behavior of Al Alloy Composites
Authors: Karibeeran Shanmuga Sundaram , Sathishkumar Dhanalakshmi , Muthaih Balasubramanian , Palanivelu Sivakumar
Published: March 2016

Aluminum based metal matrix composites offer greater potential for light weight, wear resistant and high temperature applications. Secondary processing like extrusion results in the improvement of strength and ductility of the as-cast composites. The objective of this research is to investigate the effect of reinforcement type and extrusion process on the microstructure and mechanical properties of the hot extruded Al2014 aluminum alloy. Two different composites were made by reinforcing the alloy with 10 wt.% SiC and 10 wt.% Si3N4 particles using stir casting method. The particles were electroless Ni coated to improve the wettability of reinforcement by the matrix alloy. The composite ingots were further extruded at 475 °C with an extrusion ratio of 8:1. The microstructures and the mechanical properties of the base alloy and the composites were examined systematically. The extruded composites show more homogenous microstructure with uniform distribution of particles in the matrix alloy. Both the Al/SiC and Al/Si3N4 composites exhibited improved hardness compared to the base alloy in both as-cast and extruded conditions. It was also found from tension tests that the both the composites show higher yield strength, ductility and ultimate tensile strength (UTS) than the base alloy in the extruded condition. The reason for improvement in strength in the extruded conditions is explained in detail. Fracture surface analysis revealed the transition from brittle fracture mode in the as cast composites to the ductile fracture in the extruded condition.
Predicting Wave Propagation Through Inhomogeneous Soils Using a Finite-Element Model Incorporating Perfectly-Matched Layers
Authors: Jones Simon
Published: March 2016

A 2D, plane-strain, finite element model, with perfectly-matched layer elements acting as absorbing boundaries, is used to investigate the effect of soil inhomogeneity on resultant surface vibration. The stiffness and mass matrices for the perfectly-matched layer element is derived and included for reference. Stochastic variability of the soil’s shear wave velocity is introduced using a K-L expansion; the shear wave velocity is assumed to have a log-normal distribution and a modified exponential co-variance kernel. Results suggest that local soil inhomogeneity can significantly affect surface velocity predictions; 90% confidence intervals showing 7dB averages and peak values up to 11dB are computed. This is a significant source of uncertainty and should be considered when using predictions from models assuming homogeneous soil properties.
Influence of Frame Stiffness and Rider Position on Bike Dynamics: Analytical Study
Authors: Williams Trevor , Kaul Sudhir , Dhingra Anoop
Published: March 2016

Dynamic characteristics of a bicycle such as handling and stability can be studied during the design phase to comprehend specific aspects associated with the overall layout as well as the frame architecture. Bicycles demonstrate unique properties such as static instability that is overcome by getting them into motion with a minimum velocity threshold. The structural stiffness of a frame plays a critical role in the handling behavior of a bike. However, the influence of structural stiffness has received limited attention in the existing literature. This paper attempts to fill the gap by presenting analytical results from a study that includes the influence of rider positions on three bicycle layouts. The analytical model consists of four rigid bodies: rear frame, front frame (front fork and handle bar assembly), front wheel and rear wheel. The overall model exhibits three degrees-of-freedom: the roll angle of the frame, the steering of the front frame, and the rotation of the rear wheel with respect to the frame. The rear frame is divided into two parts, the rider and the bicycle frame, that are assumed to be rigidly connected. This is done in order to allow the model to account for varying rider positions. The influence of frame flexibility is studied by coupling the structural stiffness of the frame to the governing equations of motion. Layouts from a benchmark bicycle, a commercially manufactured bicycle, and a cargo bicycle are used for this study in conjunction with rider positions ranging from a relaxed position to an extreme prone position. All the results are analyzed and compared with some proven analytical and experimental results in the existing literature. Results indicate that some of the rider positions can play a significant role in influencing the dynamic characteristics of the bike. Structural stiffness is seen to significantly affect the weave mode, only when the stiffness is reduced substantially.
Modeling Phase Transformation Kinetics and Their Effect on Hardness and Hardness Depth in Laser Hardening of Hypoeutectoid Steel
Authors: Ghosh Suhash , Sahay Chittaranjan
Published: March 2016

Much research has been done to model laser hardening phase transformation kinetics. In that research, assumptions are made about the austenization of the steel that does not translate into accurate hardness depth calculations. The purpose of this paper is to develop an analytical method to accurately model laser hardening phase transformation kinetics of hypoeutectoid steel, accounting for non-homogeneous austenization. The modeling is split into two sections. The first models the transient thermal analysis to obtain temperature time-histories for each point in the workpiece. The second models non-homogeneous austenization and utilizes continuous cooling curves to predict microstructure and hardness. Non-homogeneous austenization plays a significant role in the hardness and hardness depth in the steel. A finite element based three-dimensional thermal analysis in ANSYS is performed to obtain the temperature history on three steel workpieces for laser hardening process with no melting; AISI 1030, 1040 and 1045 steels. This is followed by the determination of microstructural changes due to ferrite and pearlite transformation to austenite during heating and the subsequent austenite to martensite and other diffusional transformations during cooling. Johnson-Mehl-Avrami-Kolmogorov (JMAK) equation is used to track the phase transformations during heating, including the effects of non-homogenous austenitization. The solid state nodal phase transformations during cooling are monitored on the material’s digitized Continuous Cooling Transformation (CCT) curve through a user defined input file in ANSYS for all cooling rates within the Heat Affected Zone (HAZ). Material non-linearity is included in the model by including temperature dependent thermal properties for the material. The model predictions for hardness underneath the laser and the HAZ match well with the experimental results published in literature.
Comparison Between the Numerical and Experimental Deposition Patterns for an Electrostatic Rotary Bell Sprayer
Authors: Osman Husam , Adamiak Kazimierz , Castle G. S. Peter , Fan Hua-Tzu (Charles) , Simmer Joseph
Published: March 2016

In this paper, a full 3D numerical model using ANSYS commercial software has been created to simulate the particle deposition profile for stationary and moving flat targets, assuming multiple injections of charged poly-dispersed particles. Different injection angles along three virtual rings were assumed to form a shower injection pattern. The experimental and the numerical results of deposition thickness have been presented and compared for different injection patterns. It has been found that there are some parameters, such as the total number of injection points, the radii of the rings and the fractional mass flow rate in each injection ring, which affect the numerical results of the deposition thickness and uniformity.
Optical Properties of CuZn0.8Cd0.2SnS4 Quinternary Alloy Nanostructures
Authors: Ibraheam A. S. , Al-Douri Y. , Hashim U. , Ahmed Waleed K.
Published: March 2016

Cu2Zn0.8Cd0.2SnS4 quinternary alloy nanostructures were prepared with different copper (Cu) concentrations; 0.3, 0.5, 0.7 and 0.9 mol/L using the spin coating technique. The direct band gap energy of Cu2Zn0.8Cd0.2SnS4 quinternary alloy nanostructures is investigated to decrease as Cu increases. The transmittance value in the range 63–49% is depending on Cu content.
Theoretical Analysis of Resonance Tube End Wall Heating: Solution of Unsteady Fluid Dynamic and Energy Equations
Authors: Sinha Ramlala P.
Published: March 2016

A solution of the highly complex unsteady compressible flow field inside a cylindrical resonance tube has been obtained numerically, assuming one dimensional, viscous, and heat conducting flow, by solving the appropriate fluid dynamic and energy equations. The resonance tube is approximated by a right circular cylinder closed at one end with a piston oscillating at resonant frequency at the other end. An iterative implicit finite difference scheme is employed to obtain the solution. The scheme permits arbitrary boundary conditions at the piston and the end wall and allows assumptions for transport properties. For the example considered herein, the solution predicts a rise of 95°F in the mean end wall temperature, from 60°F to 155°F, in 14.313 milliseconds which is in good agreement with the experimentally observed values. The solution would also be valid for tapered tubes if the variations in the cross-sectional area are small. In successfully predicting the resonance tube results, an innovative simple but stable solution of unsteady fluid dynamic and energy equations is provided here for wide ranging research, development, and industrial applications in solving a variety of complex fluid flow heat transfer problems. The method is directly applicable to pulsed or pulsating flow and wave motion thermal energy transport, fluid-structure interaction heat transfer enhancement, and fluidic pyrotechnic initiation devices.
Working Procedure for Early Proactive Geometry Assurance Considering Manual Assembly Complexity
Authors: Rosenqvist M. , Falck A-C. , Söderberg R.
Published: March 2016

The purpose of this paper is to explore how a recently developed method for evaluation of the impact of assembly complexity on manual assembly concepts should be used, by whom and how this would fit into an industrial product development process.

The explored method incorporates both sensitivity to geometrical variation and assessment of assembly complexity and is integrated into the CAT (Computer Aided Tolerancing) tool RD&T.

A baseline of a generic six phase product development procedure is summarized with focus on the part of the process that handles geometry assurance; the geometry assurance process.

The result is a proposed working procedure for proactive geometry assurance considering manual assembly complexity as a part of a geometry assurance process.

The proposed working procedure supports the development of products that have a high level of geometrical robustness and a low level of manual assembly complexity resulting in higher quality, less costs related to poor quality and less waste.

Need for further research is also identified since the current tools for assessing manual assembly complexity do not support all geometry assurance activities needed. One suggestion is to expand the current calculation models to interact with the variation analysis in CAT through assembly tolerances.
Modeling and Simulation of Structurally Dynamic Crystallizable Shape Memory Polymers With Light-Induced Bond Exchange Reaction
Authors: Cui Fangda , Rao I. Joga , Moon Swapnil
Published: March 2016

Shape Memory polymers (SMPs) is a novel class of smart polymeric materials that have been attracted tremendous scientific interest within the last decades. SMPs have the ability to “remember” their original shape even after undergoing significant deformation into a temporary shape. For most first generation of SMPs, the shape memory effect was accomplished by a thermally induced process, triggered in many different ways, such as heating/cooling, electromagnetic field and infrared light. The transient shape in thermally induced SMPs is due to a glassy phase or a semi-crystalline phase. The thermally induced SMPs which temporary shape is fixed through crystallization is called crystallizable shape memory polymers (CSMPs). For traditional CSMPs, their original shape is predefined and is not able to be reprogrammed. This limits the applications of the CSMPs. Recently, a new class of CSMPs has been developed. These materials can perform a typical thermally induced shape memory cycle, but their original shape can be reprogrammed through exposing to UV light. The shape reprogramming effect is governed by light induced covalent bonds exchange reaction, while the shape memory effect-as typical CSMPs-is due to solid-phase crystallization. In this work, we focus on modeling the mechanical behavior of this new class of structurally dynamic CSMPs. The framework used in developing the model is built upon the theory of multiple natural configurations[1]. The model has been applied to solve a specific boundary condition problem, namely uni-axial tension. Furthermore, we implement our model through Abaqus (commercial finite element package) subroutine UMAT to simulate 3D behavior of this attractive material.
Jet-A Combustion in an Indirect Injection Compression Engine Versus a Direct Injection Compression Engine at Same Load and Speed
Authors: Soloiu Valentin , Naes Tyler , Muinos Martin
Published: March 2016

This study compares combustion of Jet-A in an indirect injection (IDI) compression ignition engine and a direct injection (DI) compression ignition engine at the same load and speed. The Jet-A was blended (75Jet-A): 75% Jet-A and 25% Ultra Low Sulfur Diesel # 2 (ULSD) by mass. Both engines had a load of 4.5 bars Indicated Mean Effective Pressure (IMEP) and were run at 2000 RPM.

The IDI engine configuration was very similar to that used in High Mobility Multipurpose Wheeled Vehicles (HMMWV).

The research showed that combustion pressure in the IDI engine separate combustion chamber was 81 bars versus 71 bars in the main combustion chamber showing high gas-dynamics losses at transfer passages while in the DI engine the peak pressure reached 65 bars.

The Apparent Heat Release Rate (AHRR) in the IDI engine has both the premixed and diffusion stage combined while in the DI classical combustion there are visible both the premixed and diffusion burn stages. The results show that in both engines there is a Low Temperature Heat Release (LTHR) region before top dead center (BTDC). The mass averaged instantaneous temperature reached 1750 K in the direct injection engine being the same for both fuels and for the IDI engines reached 1700 K in main combustion chamber and 1950 K in the separate combustion chamber for both fuels.

The study showed that there are significant differences in the shape of the AHRR between the engines, nevertheless, the Jet-A has very similar combustion characteristics with ULSD in both combustion systems making a viable option as a substitute fuel to use in High Mobility Multipurpose Wheeled Vehicles (HMMWV).
Optimal Size and Location of Capacitors on Power Distribution Lines
Authors: Reitz Max A. , Wang Xin
Published: March 2016

Shunt capacitor banks are used on power distribution feeders to reduce losses and regulate the voltage level. The decrease in transmission line current also leads to an increase in the amount of demand that can be supplied without increasing the size of the conductors. In order to maximize the benefit of adding capacitor banks to the distribution feeders, the optimal size and location of the capacitors must be determined. This paper presents a novel optimal control approach to both regulate the voltage drop and reduce the copper loss. A cost function that penalizes both energy losses and voltage drop is developed. The optimal size and location of capacitors can be found using the optimal control solution. Computer simulation results are compared with existing methods of determining the optimal size and location of capacitors. Our approach improves on current methods by providing flexibility to both regulate voltage levels and reduce losses.
Smart Power Grid Synchronization With Nonlinear Estimation
Authors: Darvish Hossein , Wang Xin
Published: March 2016

Grid synchronization is a critical concern for proper control of the energy transferred between the Distributed Power Generation System (DPGS) and the utility grid. Nonlinear estimation techniques are proposed to track the voltage magnitude, phase angle, and frequency of the utility grid. Instead of directly analyzing in abc coordinate frame, the symmetrical component is employed to separate the positive, negative, and zero sequences in the transformed αβ stationary coordinate frame. By using αβ stationary coordinate frame, the number of system state variables is reduced to five. The results show that our proposed nonlinear estimation technique is efficient in smart power system synchronization. The MATLAB simulation studies have been conducted to compare the performance of Extended Kalman Filter (EKF), Particle Filter (PF), and Unscented Kalman Filter (UKF). Computer simulations have shown that the efficacy of our proposed nonlinear estimation methods including the Extended Kalman Filter, Particle Filter, and Unscented Kalman Filter. It also shows that the Unscented Kalman Filter, and the Particle Filters are better estimators, because voltage synchronization problem is nonlinear system, and linearization process which the Extended Kalman Filter is based on is not very accurate. The number of particles in Particle Filter can be increased to improve the accuracy, but there exists a trade off between computational effort and estimation accuracy. In our research, with consideration the same computational complexity, we calculate the Mean Square Error (MSE) to examine the performances of different nonlinear estimation approaches. By comparing the MSE of different estimators, we prove that the Unscented Kalman Filter shows the most accurate performance in voltage synchronization for three phase unbalanced voltage. Our results have shown the potential applications in the future smart power grid synchronization.
Experimental Study on Electromechanical Failure of Dielectric Elastomer Actuator
Authors: Liu Xuejing , Jia Shuhai , Chen Hualing , Li Bo , Xing Yu
Published: March 2016

The dielectric elastomer (DE) is an insulating membrane with extra-ordinary properties which can meet various electromechanical failures during the actuation. In the current work, we measured breakdown voltage in DE membrane with special focus on the varying boundary stress during the actuation process. The boundary stress tuned deformation state, causing the membrane to deform out-of-plane before breakdown. A theoretical model is presented, involving the strain-stiffening effect in material and boundary stress effect in geometry, to estimate the dielectric breakdown voltage. The results agree with the experiments. Then, another set of experimental investigation is conducted to study the voltage-induced wrinkling of DE membrane. Steady wrinkles, without an accompany of electrical breakdown are attained and three different failure modes of DE membrane are classified into a phase chart. Finally, a qualitative theoretical explanation on wrinkling mechanism of DE membrane is presented and verified by experimental observations.
Model Predictive Control of an HVAC System Based on Dynamic Tracking and Optimization of Energy Use
Authors: Díaz Jácome Alfredo , Sanjuán Marco E. , Fontalvo Morales Victor , Audivet Durán Cinthia
Published: March 2016

U.S. Department of Energy affirms that HVAC systems consume approximately 40% of the total energy used in commercial-building sector. These types of systems are complex because they are composed of a large number of interconnected subsystems. The analysis shown in this paper is established on a building geographically located at the Caribbean coast region of Colombia in a region with tropical savanna climate and it is exposed to constant thermal load changes associated to high wall temperatures and direct sunlight incidence. Under this perspective, an energetic analysis is performed for the HVAC in order to implement a Model Predictive Control (MPC) strategy to enhance the system efficiency under the previously mentioned external conditions. The model predictive strategy is implemented as a system supervisor in order to minimize a cost function that measures the ratio of water consumption to air temperature change in the cooling coil. The strategy manipulates the required temperature of supply water to cooling coil from the chiller, perceiving as input perturbation the outdoor temperature, the desired temperatures for the classrooms and the desired temperature of the air supply to the different zones. The comparison and selection of thermodynamical states for analysis are conducted according to the dynamic characteristics of the entire system and individual components, and the energy assessment is performed including the system transient response. The accomplishment of the supervisory control strategy has demonstrated that dynamic energetic analysis and assessment is an auxiliary tool for HVAC performance management. The analysis performed shows that the supervisory strategy can reduce properly the energy performance index as a consequence, the energy consumption of the fan has a reduction of a 0.65%, while the water required shows a reduction of 66.93%.
Numerical Study of CO and CO2 Emissions From Rural Kitchen in Developing Countries
Authors: Rahman M. Hamidur , Islam A. K. M. Sadrul , Amin M. Ruhul
Published: March 2016

In this study the pattern and varying intensity of CO and CO2 emission from different kinds of Biofuel used in the rural areas of developing countries have been investigated. A typical rural kitchen of dimension 3.0m × 1.5m × 2.2m is constructed with an improved concrete oven. We have measured the source concentration at the stove and used the value for the numerical model. In the current analysis it is observed that at closed ventilation condition, CO and CO2 concentration exceeds safe limiting value. Even under the natural ventilation, it fails to keep the concentration below the safe threshold. However in forced ventilation system at 5m/s, the concentration level drops significantly. At the breathing point, for a source concentration of 338 PPM and without any ventilation, numerical results predict the CO concentration to be 70 PPM. Natural ventilation case shows no improvement while forced ventilation suppresses the concentration by 70%. On the other hand, for a no ventilation condition, CO2 concentration is found to be as 2050 PPM when the source level concentration is 7100 PPM. Forced ventilation at 5m/s decreases the concentration to 750 PPM, well within the safe limit. High concentration was found to accumulate beneath the roof and on the top of the stove. It is then dispersed to the entire upper region of the kitchen. Deploying a duct in the exact spot shows that forced ventilation captures most of the fume and decreases dispersion along the roof. In no ventilation and natural ventilation cases, high concentration accumulation can be observed in the lower-left and lower-right corners, both in longitudinal and lateral planes which eventually affects the breathing zone concentration. On the other hand, for forced ventilation case, concentration at lower-left and lower-right corner is greatly reduced resulting low concentration at the breathing zone.
Thermal Analysis of Friction Stir Welding Process Under Different Control and Energy Parameters
Authors: Yi Dalong , Zhang Hui
Published: March 2016

Friction Sir Welding (FSW) process is a solid state welding technology which is widely used in manufacturing field for joints of many types of same or dissimilar materials such as aluminum alloys, magnesium alloys and steels and so on. In addition, FSW process is also a complex process associated with heat transfer, plastic deformation, grain recrystallization and material property changing phenomenon. It is commonly known that the thermal condition or the temperature distribution of space and time is important to the final welding condition. However, due to the limitation of experiment measurement and the unfinished work of numerical heat transfer model, the relationship between thermal condition and control parameters still remains a question. In this work, a new numerical model based on energy analysis and finite element method is built to calculate the thermal field of FSW process. The energy generation due to plunge depth and the converting coefficient of friction energy to heat are considered in the model. The effects of energy distribution of both sides, energy efficiency of friction, plunge depth, normal force, traverse speed and rotation speed on the temperature distribution of FSW process are investigated.
Preliminary Investigation of Novel Direct Contact Ultrasonic Fabric Drying
Authors: Momen Ayyoub M. , Kokou Edem , Bansal Pradeep , Gluesenkamp Kyle R. , Abdelaziz Omar
Published: March 2016

Thermal evaporation of moisture from clothes is the main technique used in clothes dryers today. Most of the energy supplied is spent to provide the latent heat of evaporation of water (2.5MJ/kg). This paper presents a novel direct contact ultrasonic system to mechanically remove water from wet fabric. The vibrations from the transducers are transferred by direct contact to the water inside the narrow pores of the clothes. Breaking the capillary adhesion of moisture at the interface between air and water allows water to exit the clothes as cold mist. The cold mist also carries with it most impurities such as minerals or detergents. This cannot be achieved in thermal dryers where water evaporates and leaves the impurities behind. Mechanical extraction of water is expected to be more efficient since thermal processing is not required. The majority of the supplied energy is used to mechanically separate water from the fabric. Initial testing has revealed that it is possible to dry a 1 cm2 piece of fabric from full saturation to a mere 0.4 % moisture content in just 14 seconds.
Thermal Conductivity of Individual Electrospun Polymer Nanofibers
Authors: Ma Jian , Zhang Qian , Mayo Anthony , Mu Richard , Bellan Leon , Li Deyu
Published: March 2016

In this work, the thermal conductivity of individual polyethylene (PE) nanofibers fabricated by electrospinning was experimental measured. Our results show that polyethylene nanofibers can have a thermal conductivity up to 2.6 Wm−1K−1, (more than 9 times higher than the bulk PE value) and that the thermal conductivity is strongly correlated with the electric field intensity used in electrospinning. This, combined with micro-Raman characterization of individual nanofibers, suggests that the enhanced thermal conductivity is due to the high degree of orientation of the polymer chains. The stronger elongational forces experienced by the jet at higher electrospinning voltage result in the formation of nanofibers with a higher degree of molecular orientation. Similar thermal conductivity enhancement is also observed with other polymer nanofibers including polyethylene oxide (PEO), Nylon-6, and polyvinylidene fluoride (PVDF). Collectively, our results indicate that electrospinning could be an effective approach to produce polymer nanofibers with enhanced thermal conductivity.
Thermal Interface Conductance Between Aligned Polyethylene and Graphite
Authors: Lv Wei , Henry Asegun
Published: March 2016

Molecular dynamics simulations are used to provide fundamental insights into the thermal interface resistance between aligned polyethylene chains and graphite layers using the Reactive Force Field (ReaxFF) potential[1] to describe the atomic interactions. We find that the interfacial conductance could alter more than two orders of magnitude when changing orientation of polymer fibers to graphite. This finding suggests that, by using highly stretched polymer fibers, one could then maximize the interfacial conductance to engineer high thermal conductivity polymer composites.
Fluidized Bed Air Gasification Using Low Heating Value Sand-Bedded Dairy Manure and Sludge Pellets
Authors: Nam Hyungseok , Maglinao Amado , Capareda Sergio
Published: March 2016

Solid manure handling is a major environmental issue confronting animal facilities in the United States. One difficulty in using dairy manure as a fuel source is the presence of sand bedding used for lactating dairy cows. More than 30% of dairy farms use sand beds for a dry and clean environment that prevents bacterial growth [1]. In this study, dairy animal manure obtained directly from waste lagoons was used for the air gasification process. The manure was dried to reduce the moisture down to 5% and a sand separating system was designed to remove some sand bedding materials. Preliminary air gasification experiments showed that the direct use of dairy manure containing 75% ash content, that reflect high sand content, reduced the temperature of the reactor. The study is also aimed at handling unprocessed dairy manure and generating electric power for the on-site use. A high heating value manure is needed to run the gasifier and the produced synthesis gas (or syngas) is fed to an engine coupled with a generator. Some dairy manure gasification work were done using fresh dairy manure. The highest heating value from the dairy manure biomass was found to be 4.5MJ/kg in a fixed-bed gasifier [2]. Another gasification study using a fluidized-bed reactor could produce syngas heating value as high as 4.7MJ/m3 from dairy manure [3]. A bench-scale fluidized bed containing a 3-inch diameter reactor tube with a cyclone and a scrubber was used to gasify dairy manure using air at different temperatures. The sand separated dairy manure used in this study contained approximately 45% ash content. The maximum heating value of the synthesis gas was 3.8MJ/m3 at an operating temperature of 750°C. The syngas will need to be upgraded. To upgrade the synthesis gas heating value, sludge pellets of 18.7MJ/kg were mixed with the dairy manure in different ratios of 10% and 30%. The syngas heating values from mixed manure with sludge pellet were increased to 5MJ/m3 with 10% sludge, and 5.7MJ/m3 with 30% sludge. The sludge used has higher heating value resulting in higher gas HV. The cold gasification efficiency was achieved as high as 36±5% with dairy manure mixed with sludge pellet. At a higher operating temperature, higher efficiency was obtained with increased gas composition of hydrogen and carbon monoxide. This syngas may then be used for power generation as well as possible input gas for the Fisher Tropsch process for liquid biofuel production. The result of the experiments will be a cornerstone for the widespread application of low heating value animal waste for producing high heating value syngas that may be used for electric power generation as a result of various upgrading processes.
Morphological Characteristics and Fractal Analysis of Diesel Particulate Matter From TEM Images Produced by Dual-Fuel N-Butanol Injection
Authors: Ruiz Frank A. , López Andrés F. , Agudelo John R.
Published: March 2016

This work analyzes the morphological characteristics and fractal dimension of diesel particulate matter (DPM) produced by multipoint-intake fumigation of n-butanol in a diesel engine. A novel methodology based on digital images processing (DIP) of micrographs from transmission and scanning electron microscopy (TEM and SEM) is presented. Two DIP algorithms were developed and compared for identification and cleaning of TEM images background: the semi-automatic (supervised), which uses the Watershed transform, morphological operators and edge detectors; and the automatic (non-supervised), which further includes adaptive threshold methods. Both algorithms performed successfully when compared with manual methods allowing a significant time saving (from 12 hours manual to 2 minutes automatic). Results showed that mean primary particle diameter (dp0), mean particulates agglomerates diameter, and fractal dimension of the agglomerate (Df) of DPM, which were around 30 nm, 70 nm, and 1.9 dimension respectively, were not affected by n-butanol fumigation in comparison with Ultra-low sulfur diesel (ULSD). The algorithms were sensible to the manual selection of the primary particles from the micrographs, strongly affected the determination of total number of primary particles (np0) and its diameter of gyration (dg); but the Df is not affected. Both algorithms performed successful avoiding the user subjectivity and providing significant time saving during the analysis.
Upper Airway Dynamic Characteristics-Comparative Study Between Healthy Subjects and OSA Patients
Authors: Ashaat Sherif , Al-Jumaily Ahmed M. , Huang Loulin
Published: March 2016

The human upper airway (UA) dynamic characteristics differ from healthy subjects to obstructive sleep apnea (OSA) patients. Having a common term of reference for comparison is very difficult as many anatomical parameters are involved; namely: volume of airway, uvula, tongue, and air gaps at the rear of the mouth. This study investigates these characteristics for healthy and OSA subjects and proposes new common ground parameters for comparison. The objective of this study is to identify the causes of collapse by comparing these characteristics between those subjects. Magnetic resonance imaging (MRI) data of the UA expanding from nasopharynx to the hypopharynx were conducted on 8 healthy subjects and 10 OSA patients. 3D models were constructed and simulated. Measurements of the UA were evaluated and compared in both groups. The outcomes support the fact that the air volume is not the main contributor for the UA collapse and show that the apneic events are caused by the large size of the tongue and uvula. Finally, the natural frequencies for the uvula and tongue were very close in both participating groups.
Automated Gaging of Surface Texture on Engine Components
Authors: Oktay Turker
Published: March 2016

Surface texture of engine components such as crankshafts and camshafts is one of the most important factors that determine the performance, efficiency and the operating life of an internal combustion engine. Current practices and the challenges faced by design engineers in specifying the target surface topography to meet these goals have been reviewed. Once specified, the surface texture must be measured fast, accurately and repeatably in the rough environment of an engine manufacturing plant. The key components of an automated skidded surface finish measuring gage designed with these criteria in mind are described in this paper. The gage has 7 axes of motion and 3 stylus probes oriented in the axial and radial directions to take axial and facial measurements on journal and cam lobe surfaces and thrust bearing surfaces. The selection of surface texture parameters to best describe the desired surface texture of these engine components was investigated. The final stage of surface preparation is often the superfinishing process. The measurement gage must be able to provide the sensitivity and repeatability that are required for measuring the finely finished surfaces generated by this process. Typical surface texture results of a superfinishing process achieved on crankshafts are described. The results of a Gage Repeatability and Reproducibility (R&R) study performed on the surface texture measuring gage are presented.
Computer-Aided Diagnostic Tool for Lung Diseases
Authors: Wang Lulu , Al-Jumaily Ahmed , Kilding Andrew
Published: March 2016

Exercise-induced bronchoconstriction (EIB) and Exercise-induced asthma (EIA) are used synonymously to describe acute lung airway narrowing occurring during and/or after exercise. Tools usually used by health practitioners to assess the severity of EIB or EIA symptoms include bronchodilator tests and various bronchial provocation procedures including spirometer and eucapnic voluntary hyperpnoea (EVH) challenge system, there is no tool that is able to monitor the severity of acute lung airway narrowing. This study aims to design a graphical user interface (GUI) to monitor the severity of acute lung airway narrowing using MATLAB software. The GUI will present the measurement data into a simple and user-friendly program consisting of patient information, EVH test analysis and detection of EIA and EIB. Success of this project widens the usage of EVH challenge in medical areas and the GUI may serve as a new clinical computer-aided diagnostic tool to help healthcare professionals non-invasively monitor the severity of asthma, EIA and EIB.
Energy Harvesting With a Piezoelectric THUNDER
Authors: Wang Fengxia , Wu Wei , Lozowski Andy , Alizadehyazdi Vahid , Abedini Amin
Published: March 2016

In this work the energy harvesting performance of a piezoelectric curved energy generator (THUNDER) is studied via experimental and analytical methods. The analytical model of the THUNDER is created based on the linear mechanical electrical constitutive law of the piezoelectric material, the linear elastic constitutive law of the substrate, and the Euler-Bernoulli beam theory. With these linear modal functions, the Rayleigh-Ritz approach was used to then obtain the reduced mechanical electrical coupled modulation equations.

With above analytical model two types of energy harvest circuit are proposed and compared: 1) directly charging mode at low level excitation, and 2) memory stored optimal duty cycle step-down converter mode at high level excitation. The value of the optimal duty cycle is determined based on the characteristics of the vibration signals of the ambient vibration source. To reduce the energy consumption of the microcontroller, the optimum duty cycle values are stored in the microprocessor instead of doing onsite computing during energy harvesting process. For the purpose of designing a low power cost mechanical switch to control the operation of both modes, the threshold voltage between these two operation modes is converted into threshold displacement.
Experimental Study of a Water Desalination System Based on Humidification-Dehumidification Process Using a Heat Pump
Authors: Hegazy Anwar H. , Teamah Mohamed A. , Hanafy Ahmed A. , El-Maghlany Wael M.
Published: March 2016

In this paper an experimental investigation on a lab scale HDH water desalination unit using a Heat pump was presented. From the thermodynamic view, it was found that the electric heater has a coefficient of performance equal unity, while the heat pump has a coefficient of performance greater than one; in other words the dissipated heat has a high scale. In addition, the refrigeration effect could be used as a secondary benefit. The proposed system utilizes the heat rejected and the cooling effect of the mechanically driven vapor compression heat pump for fresh water production. A test rig consisting of a fan, condenser duct, water spray humidifier and evaporator duct was constructed to study the performance under different operating conditions. The effect of air flow rate variation and water spraying direction (cross, counter or parallel) in the humidification process were studied. Experiments were carried out under variable inlet air conditions. Air flow rate was varied from 0.076 m3/s to 0.4054 m3/s. Results showed that cross water spraying humidification tests yielded the highest production rate. The unit’s maximum production rate was found to be 2.8 Liters/hour at a power 1.4091 kW.
Energy Harvesting Circuit for Energy Re-Generator Shock Absorber With Impulse Excitation to a Vehicle
Authors: Wu Wei , Wang Fengxia , Lozowski Andy G.
Published: March 2016

The inadequate power harvested from piezoelectric materials makes online tuning of the converter duty cycle and switching frequency a difficult task. This paper presents an open-loop control with pre-computed duty cycle profiles to minimize power consumption. Considering the real input signal to the shock absorber is non-sinusoidal when the vehicle passes through a bump, it is beneficial and necessary to apply a suitable duty cycle profile to every impulse excitation so that the power yield is maximized. The power expense is greatly reduced by first calculating offline the array of optimum duty cycle profiles matching a variety of impulse responses using the shock absorber performance model. The profiles are then stored into the micro-controller look-up table and used as needed during the operation of the vehicle.
Fabrication of 2.5D Rock-Based Micromodels With High Resolution Features
Authors: Park Daniel S. , Upadhyay J. , Singh V. , Thompson Karsten E. , Nikitopoulos Dimitris E.
Published: March 2016

Fabrication of 2.5D rock-based micromodels with high resolution features is presented using SU-8 multi-layer lithography and nickel electroforming for nickel molds. Processes associated with SU-8 were carefully optimized by the use of the vacuum contact, the use of UV filter, and controls of UV exposure doses and baking times. The use of SU-8 MicroSpray enabled the easy fabrication of multi-layers of SU-8, while exhibiting some total thickness variations. The thirteen layered SU-8 samples showed reliable patterning results for features at 10 and 25 μm resolutions, and minor pattern distortions of features at the 5 μm resolution. Flycutting method employed in multi-layer lithography of SU-8 yielded accurate total thickness control within ±1.5 μm and excellent pattern formation for all of 5, 10, and 25 μm features. Electroforming of nickel was optimized with electroplating bath composition and electroplating parameters such as current density to realize the high resolution nickel mold. The fabricated nickel molds from flycutting based SU-8 samples revealed the feasibility of manufacturing the minimum features down to 5 μm for thirteen layers without any pattern distortions. The replication-based micromolding method will allow for fabrication of micromodels in a variety of materials such as polymers and ceramics. The high resolution, 2.5D micromodels will be used for investigation of pore-scale fluid transport, which will aid in understanding the complicated fluidic phenomena occurring in the 3D reservoir rock.
Reliability-Based Component Design
Authors: Osakue Edward E. , Anetor Lucky , Odetunde Christopher
Published: March 2016

This paper uses the lognormal probability function to modify deterministic design equations into probabilistic design, thereby transforming the traditional safety factor into a reliability factor. The reliability factor is related to the coefficients of variation (covs) of design parameters and a failure probability. An approximation of the reliability factor for initial sizing is defined as probabilistic design factor. The serviceability design model parameters are treated as random variables characterized by mean values and covs. The cov of the design model is obtained by using first order Taylor series expansion. Multiple serviceability criteria such as bending strength, lateral torsional stability, transverse deflection, and fillet weld strength are considered.

The results from this study compare favorably with previous ones and sometimes give solutions with lower weight. In the first example, the solution in the present approach deviates on the conservative side from the previous one by 2.6% for 99.9% reliability and 3.8% for 99.997% reliability. These results are practically the same, suggesting that the method presented is reasonable and accurate. In the second example, the beam in the new solution has 23.65% lower volume or weight and the weld bead volume is lower by 8.4%. This suggests possible substantial cost reductions. From the sizes of the beam and weld bead, it can be concluded that the “factor of reliability” approach of this study and the stochastic Monte Carlo simulation method used previously are in good agreement.

Due to the very good results from the examples considered, it seems reasonable to say that the “factor of reliability” method presented is a satisfactory model. The approach has the advantage of being much less computationally intensive and requires no specialized software or skills. These features can lead to cost savings in design projects. Design sizes from this method may be used to create solid models which can be optimized using FEM (Finite Element Method). In addition, and from an instructional perspective, the method could be used to introduce undergraduate engineering students to probabilistic design approaches.
Stick-Slip Simulation and Detection in Mechanical Face Seals
Authors: Valigi Maria Cristina , Braccesi Claudio , Cianetti Filippo , Logozzo Silvia
Published: March 2016

The present paper proposes a new model and method to detect the occurrence of dynamic instabilities and stick-slip in mechanical face seals used in automotive cooling water pumps, in order to improve their performance. A new tribo-dynamic model is presented and used to examine how many and what design parameters influence stick-slip. Mass, moment of inertia, stiffness, damping ratio, friction relationship, viscosity, roughness and wear, compressive strength of different coupling materials, geometrical specifications and temperature are some of the analyzed parameters. Therefore, this work provides a full overview of the influence of design parameters on the stick-slip phenomenon.