bluuebunny/crossref_metadata_2025 huggingface dataset:
Structural Micro Processing of Haversian Systems of a Cortical Bovine Femur Using Optical Stereomicroscope and MATLAB
Authors: Hage Ilige S. , Hamade Ramsey F.
Published: October 2013

Processing of optical images of bone has been a topic of considerable interest in the past and continues to be so. Image processing can be used in medicine in order to improve the image visualization to detect diseases, and to compute properties such as area for abnormal cells. Several studies of bone images have been conducted using several methods including segmentation and image enhancement. The aim of this paper is to generate a standalone automated code for segmenting colored optical microscope images in order to show the microstructure of a cortical bone as a multi-phase (here 4 phases) composite: Lamella (matrix), Haversian canals, osteoblast lamella boundaries (freshly generated lamella lining), and lacunae (containing living cells).

For this purpose, we investigate the use of MATLAB, which contains image-processing toolboxes with many analytical capabilities that have been advertised to be useful for many applications including biological systems. In this work, such capabilities are utilized in image processing of the microstructure of bovine cortical bone, which is generally accepted as proxy for human bone. Two specimens of the cortical regions of a bovine femur bones were imaged using Olympus optical microscope. One of the specimens was treated with the Masson’s trichrome staining treatment and the other with the Hematoxylin and Eosin (H&E) treatment. The images from the microscope were captured using a DP12 camera.

Furthermore, MATLAB results are contrasted against Stream®, a commercially available software package procured along with the Olympus optical microscope. Via color-coding to facilitate the bone microstructure identification, the image analysis results were compared after computing the areas of each of the 4 constituent microstructural phases. Areas of each phase were calculated and comparisons made between the results obtained from the Stream® software and those obtained from MATLAB. The relative error was found to be quite small (<1%), which proves that MATLAB may be an effective software for medical image processing and may be the tool of choice for standalone applications.
Parametric Design and Optimization for Impingement Jet Heat Transfer Over Dimpled Topologies
Authors: Negi Deepchand Singh , Pattamatta Arvind
Published: October 2013

A large number of experimental and theoretical studies investigating heat transfer of impinging jet and jet arrays exist in the literature. However, there are only a few experimental and numerical studies that consider the heat transfer performance of the impinging jet and jet array over complex impinging surface topologies. In spite of these studies, several other factors concerning the dimpled target plate configuration such as dimple height, diameter, pitch spacing between dimples, and their effects on the heat transfer coefficient have not yet been well apprehended. The purpose of the present study is to address some of these aspects through a detailed computational investigation of 3D impinging jet interaction on dimpled target plates. The initial section of the study is focused on the evaluation of different turbulence models in capturing the complex flow features associated with dimpled topology. These models are validated for Nusselt number against previous experimental data in literature. This is followed by a parametric study in which geometric parameters of the dimpled target plate such as dimple diameter, pitch spacing between dimples and dimple height are varied to understand their role on heat transfer enhancement. The final section of the study deals with the optimization of the above geometric parameters based on three factorial design of parametric space. Results from these designed simulations are used to construct a surrogate model based on response surface analysis and the optimized configuration is determined. The objective functions for optimization include maximizing the average Nusselt number, Nuavg, and minimizing the deviation of maximum Nusselt number, Numax-sd. With respect to the reference configuration there is 12% and 8.58 % increase in the average Nusselt number values for the optimized case corresponding to Reynolds number of 3000 and 8200 respectively. Enhancement in terms of Nusselt number is observed with the dimpled target plate over corresponding non dimpled target plates.
Electrothermal Pumping With Thin Film Resistive Heaters
Authors: Work Andrew , Velasco Vanessa , Williams Stuart J.
Published: October 2013

Rapid Electrokinetic Patterning (REP) is a technique used to gather suspended colloidal particles at a planar electrode surface. REP is capable of gathering colloids using very simplistic electrode geometry. Two parallel plate electrodes are used to supply an AC electric field, and an infrared laser is required to heat the surface. Gold and indium tin oxide (ITO) on glass slides have been used as electrode material. Experiments were conducted using ITO coated glass slides, a 980 nm infrared laser, one-micron red fluorescent polystyrene particles, and an aqueous KCl solution. An inverted Nikon Eclipse microscope was used, and video was captured using a PCO Sensicam camera.
Acoustic Analysis of the NREL Phase VI Wind Turbine
Authors: Chen Yng-Ru , Ameri Ali A. , Alexander J. Iwan D.
Published: October 2013

The goal of this work is to utilize computer simulation to predict the aerodynamic noise emitted from the NREL Phase VI Wind Turbine at the different revolutions per minute.
Pitfalls for Accurate Steady-State Port Flow Simulations
Authors: Yang Xiaofeng , Chen Zhaohui , Kuo Tang-Wei
Published: October 2013

Steady-state port flow simulations were carried out with a commercial three dimensional (3D) Computational Fluid Dynamics (CFD) code using Cartesian mesh with cut cells to study the prediction accuracy. The accuracy is assessed by comparing predicted and measured mass-flow rate and swirl and tumble torques at various valve lifts using different boundary condition setup and mesh topology relative to port orientation. The measured data is taken from standard steady-state flow bench tests of a production intake port. The predicted mass-flow rates agree to within 1% with the measured data between the intermediate and high valve lifts. At low valve lifts, slight over prediction in mass-flow rate can be observed. The predicted swirl and tumble torques are within 25% of the flow bench measurements. Several meshing parameters were examined in this study. These include: inlet plenum shape and outlet plenum/extension size, embedded sphere with varying minimum mesh size, finer meshes on port and valve surface, orientation of valve and port centerline relative to the mesh lines. For all model orientations examined, only the mesh topology with the valve axis aligned closely with the mesh lines can capture the mass-flow rate drop for very high valve lifts due to flow separation. This study further demonstrated that it is possible to perform 3D CFD flow analyses to adequately simulate steady-state flow bench tests.
Automatic Geometric Recognition of Weld Beads for Supporting Virtual Prototyping and Cost Estimation of Welding
Authors: Raffaeli Roberto , Malatesta Marco , Mandolini Marco , Germani Michele
Published: October 2013

Welding is widely used in industry for products made of joined sheet metal parts and beams. The virtual prototyping process of welds in standard CAD systems relies on functionalities to manually add weld beads to the assembly models. Weld beads can be in the form of symbolic annotations or 3D solid representations. The size of products in terms of number of parts and required weld beads makes this process cumbersome and time consuming.

This paper presents a method to analyze CAD models of product assemblies in order to automatically identify possible welds among the parts using geometric recognition rules. Adjacent faces are detected and Boolean operators on planar loops are used to identify bead paths. Beads are then split in homogeneous portions based on the topology of the connected parts. The geometrical analysis of the connected parts also allows a bead to be characterized in terms of thickness, type, length and accessibility. Finally, the user is provided with functionalities to edit manufacturing properties or exclude unwanted welds.

The approach is applied at the design stage to rapidly come to the definition of the welds. If integrated with a CAD tool, this can be used as input for an efficient detailing phase. Moreover, the paper presents an application for the cost estimation of the designed welded product. Weld beads are given a realization time, and hence a cost, based on their geometric size and employed welding technology. Some examples from the industry are presented to show benefits in terms of time savings and accuracy of the cost estimation process.
Using FAHP and D-S Theory for Evaluating the State of the Product Family
Authors: Hou Liang , Lai Rongshen , Wang Haolun , Wu Yongming , Huang Wei
Published: October 2013

It is crucial to properly evaluate the running state of the product family for the enterprises to determine the direction of product family evolution and establish the management strategies of R&D-production-marketing. In order to effectively evaluate the running state of the complex product family system in dynamic evolution with uncertainty factors, a comprehensive evaluation method of the product family state is proposed based on FAHP and the D-S Theory. Firstly, the issue of running state in the product family evolution process is analyzed from four aspects of engineering design, market demand-economy, production capacity and operations management, and on that basis, the comprehensive evaluation index system of the product family running state is established. Then, the weight coefficient of the index in each level is obtained using FAHP, and the qualitative and quantitative analysis methods are combined to make the evaluation process more objective, the evaluation rating of index in each level is calculated according to the D-S Theory, then the overall rating of the product family running state is acquired synthetically. Finally, the effectiveness of this method is verified by the case study of the running state of the small size wheel loader family.
Adaptive Vehicle Stability Control With Optimal Tire Force Allocation
Authors: Arat Mustafa Ali , Singh Kanwar Bharat , Taheri Saied
Published: October 2013

Vehicle stability control systems have been receiving increasing attention, especially over the past decade, owing to the advances in on-board electronics that enables successful implementation of complex algorithms. Another major reason for their increasing popularity lies in their effectiveness. Considering the studies that expose supporting results for reducing crash risk or fatality, organizations such as E.U. and NHTSA are taking steps to mandate the use of such safety systems on vehicles. The current technology has advanced in many aspects, and undoubtedly has improved vehicle stability as mentioned above; however there are still many areas of potential improvements. Especially being able to utilize information about tire-vehicle states (tire forces, tire-slip angle, and tire-road friction) would be significant due to the key role tires play in providing directional stability and control. This paper presents an adaptive vehicle stability controller that makes use of tire force and slip-angle information from an online tire monitoring system. Solving the optimality problem for the tire force allocation ensures that the control system does not push the tires into the saturation region where neither the driver nor the controller commands are implemented properly. The proposed control algorithm is implemented using MATLAB/CarSim® software packages. The performance of the system is evaluated under an evasive double lane change maneuver on high and low friction surfaces. The results indicate that the system can successfully stabilize the vehicle as well as adapting to the changes in surface conditions.
Development of Inner Rotating Core for a Molding Machine With Topology Optimization
Authors: Park Hong Seok , Dahal Prakash
Published: October 2013

Sulfur polymer concrete (SPC) is relatively new material used to replace Portland cement for making drain pipes currently being manufactured by horizontal spun technology which produces non-homogenous material distribution and low strength pipes. Due to drawbacks of existing machine, there is a necessity to design molding machine with improved technology for assuring homogenous compaction of material. In this research, a new machine is designed where inner rotating core is the main component for mixing, compressing and giving final shape of product. So, it is necessary to optimize this part in terms of topology to ensure robust functionality.

First, the concept of a new molding machine was designed through problem exploration, idea generation, concept evaluation, and design improvement. The alternative was generated in consideration of customer requirements by applying TRIZ principles to overcome drawback of existing machine. One of the concepts was selected using scoring techniques where concepts are presented and compared with varieties of evaluating criteria. Topology optimization with density method has applied to design inner rotating core part for mass reduction and thereby optimum utilization of design space. Suitable engineering model was built based on loads, boundary condition and constraints. Loads are applied on inner core walls during mixing and compressing of sulfur concrete. Objective is focused to minimize the developed topology by maximizing stiffness. Repeated structural analysis is done to obtain the convergence data for optimal design. Optimized finite element topology is generated as CAD model for size optimization. The optimization study provided response charts of different design variables. Sensitivity analysis of the input variables helped in identifying the importance of each design variable and their respective effects on the output model. Different design points are rated on optimization study and best design points are chosen for the final dimension of structure. CATIA, OptiStruct and ANSYS are tools used for concept design, optimization of topology. To the end optimal topology is compared with the initial designed part in terms of weight and displacement. It is concluded that topology optimized model maximizes overall stiffness resulting in better and innovative product design with enhanced performance.
Energy and Environmental Impact of Groundwater Heat Pumps in Urban Areas
Authors: Verda Vittorio , Sciacovelli Adriano , Lo Russo Stefano , Taddia Glenda
Published: October 2013

Heat pumps are expected to play a major role in future energy scenarios. Proliferation of these systems in urban areas may cause issues related to environmental impact on water basins and interactions between installations. Both issues are associated with the thermal plume produced by the heat pump during operation and are particularly evident in the case of groundwater flow, because of the advective term of heat transfer.

In this paper, the impact of heat pump installations is calculated through a thermo-fluid dynamic model of the subsurface which considers fluid flow in the saturated unit and heat transfer both in the saturated and unsaturated units. This model is coupled with the thermal request of the user and the heat pump performances through appropriate boundary conditions imposed at the wells. Various scenarios corresponding to different annual heating/cooling request, groundwater velocity, groundwater temperature variation are considered.
An Inverse Method for Controlling the Temperature Distribution in Infinite Wedge Domain
Authors: Rastgoftar Hossein , Moslehy Faissal A.
Published: October 2013

The paper presents an analytical solution for controlling the temperature distribution in infinite wedge domain. The objective is to assign the heat flux at the boundaries of the domain such that a desired temperature distribution inside the semi-infinite domain is achieved. Since the conduction equation (Laplace equation) retains its form when the infinite domain is transformed into a finite domain by conformal mapping, the infinite domain can be transformed into a disk of unit radius. Then the Laplace equation is investigated in the domain confined by a circle of unit radius. The control technique used in this paper is based on the Lyapunov approach. A Lyapunov functional is defined over the circular domain and the control heat fluxes at the boundary of the disk are assigned such that the time derivative of the Lyapunov functional becomes negative definite. Since the conformal mapping is invertible, attaining a desired temperature distribution in the circular domain leads to achieving the desired temperature distribution in the infinite domain.
Thermoeconomic Diagnosis Applied to the Transient Operation of a Microturbine
Authors: Verda Vittorio , Baccino Giorgia
Published: October 2013

The use of thermoeconomic analysis for the diagnosis of malfunctions causing efficiency reductions in energy systems has been widely discussed in the literature. The main objectives of thermoeconomic procedures are to discover malfunctions, locate the components where they have taken place, help one to identify the possible causes and quantify the impact in terms of additional energy resource consumption.

In this paper, thermoeconomic diagnosis is applied to discover possible malfunctions of a microturbine. The procedure consists in the use of compact productive models of the components, which relate their exergetic products to their resources. Two different types of productive models are used: linear model and non linear model. The latter is built using neural networks.

The main interest in the proposed application is that transient operation of the system is investigated. Results show that diagnosis can be performed both in steady state and transient conditions. The neural network model allows one to detect the anomaly with better accuracy than the linear model.
Investigation of the Measured Quality Factor Versus Polarization Voltage of a Multiple-Beam Tuning-Fork Gyroscope
Authors: Cheng Peng , Zhang Yujie , Gu Wenting , Hao Zhili
Published: October 2013

In light of the importance of the mechanical Quality factor (Q) to the ultimate performance of tuning-fork gyroscopes, this paper presents an investigation on the effect of polarization voltage on the Q of a multiple-beam tuning-fork gyroscope. An experimental study is conducted to quantify the relation of the measured Q of the gyroscope to polarization voltage. The two loss mechanisms, thermoelastic damping and anchor loss, in the device are analyzed to identify the reason behind the Q drop with polarization voltage. Using a numerical model of thermoelastic damping built upon thermal-energy method, polarization voltage is found to have a negligible effect on the Q of the gyroscope. Due to the asymmetry of the fabricated devices resulting from fabrication variations, anchor loss is identified as the cause of the Q drop with polarization voltage and an analytical model of anchor loss is further proposed to take polarization voltage into account.
A High Temperature Pressure Sensor Based on Advanced Thick Film Technology
Authors: Zhang Zongyang , Cheng Xingguo , Cao Gang , Liu Chaojun , Liu Sheng
Published: October 2013

For the purpose of pressure measurement in oil drilling industry as well as in other industrial measurement and control systems, the low cost pressure sensors that can be operated in high temperature environments are badly needed. In this paper, thick film resistors (TFRs) on 430 stainless steel (SS) substrate for high temperature strain sensor applications have been developed and evaluated. Thick film technology based steel pressure sensors (SPS) are fabricated by screen printing and firing four TFRs on a machined circular diaphragm and then the TFRs are connected in a Wheatstone bridge configuration. Finite element method (FEM) is used to optimize structure design and predict the optimal position where the piezoresistive TFRs are placed on the dielectrics-on-steel substrate. Preliminary tests show that the sensors exhibit a sensitivity of 4.83 mV/V full-scale (FS) with 0.22% FS linearity and 0.27% FS hysteresis and 0.28% FS repeatability. Moreover, the thermal zero drifts and thermal sensitivity drifts of the sensors in the whole temperature range (25 °C to +220 °C) are less than 5% FS. These results indicate that the sensors can be used in high temperature environment up to 220 °C.
Evaluation of Ligamentous Stresses in the Lower Leg Subjected to Shear, Rotation and Kick Out Commonly Seen in Dynamic Athletic Maneuvers
Authors: Belwadi Aditya , Mahi Suresh , Yang King H. , Darling Tim , Burt Bob
Published: October 2013

Lower leg ligamentous injuries are the most commonly seen injuries in sports involving complex dynamic maneuvers. These injuries are not always accompanied by bone trauma and can severely impair the skills of the player. Cleats, which commonly form part of sportsperson’s footwear, can greatly affect the stresses generated in the ligaments of the ankle, knee and hip. Literature data has shown that effectively controlling the traction between the shoe and field surface plays a key role in the forces transmitted via the athlete’s lower leg. The objective of the current study was to study the effect of modifying the cleat design on the ligamentous stresses in the ankle, knee and hip joint using field test data. The study utilized a Finite Element Lower Leg Model of a 50th percentile adult male (Wayne State Lower Leg Human Model) with appropriate boundary conditions simulating three different foot strikes commonly seen in field sports, i.e. shear, rotation and kick out. A comparison was drawn between two different cleat designs based on field test data to investigate stresses induced in the hip, knee and ankle joint ligaments of the human leg.
A Semi-Analytical Solution Method for the Adhesive Contact Between a Rigid Punch and Multi-Layered Functionally Graded Material
Authors: Chidlow Stewart , Teodorescu Mircea
Published: October 2013

The current paper proposes a semi-analytical solution method which predicts both the sub-surface stress fields and pressures that result from adhesive contact between a multi-layered functionally graded material (FGM) and a rigid punch. The FGM is deemed to consist of a homogeneously elastic coating and substrate joined together by a transition layer whose shear modulus depends on the depth coordinate in some predetermined way. It is further assumed that the FGM is in a state of plane strain so that we may perform a two-dimensional analysis.

We present analytical solutions for the horizontal and vertical displacements within the solid which hold when the applied surface pressure is known and then discuss how we may use these solutions to solve the contact problem. A selection of numerical results are then presented using this model and it is found that the algorithm proposed in this work is both accurate and computationally cheap to use.
Pseudoplastic Flow Between Concentric Rotating Cylinders With Viscous Dissipation
Authors: Hazbavi A. , Ashrafi N.
Published: October 2013

The rotational flow of pseudoplastic fluids between concentric cylinders is examined while dissipation due to viscous effects is taken into account. The viscosity of fluid is simultaneously dependent on shear rate and temperature. Exponential dependence of viscosity on temperature is modeled through Nahme law and the shear dependency is modeled according to the Carreau equation. Hydrodynamically, stick boundary conditions are applied and thermally, both constant temperature and constant heat flux on the exterior of cylinders are considered. The governing motion and energy balance equations are coupled adding complexity to the already highly correlated set of differential equations. Introduction of Nahme number has maintained a nonlinear base flow between the cylinders. As well, the condition of constant heat flux has moved the point of maximum temperature towards the inner cylinder. In the presence of viscous heating, the effect of parameters such as Nahme, Prandtl and Brinkman numbers, material time and pseudoplasticity constant on the stability of the flow is presented in terms of neutral stability curves. The flow parameters along with viscosity maps are given for different scenarios of the flow.
Modeling of Heat Transfer in Shape Memory Polymer Nanocomposites
Authors: Carrell John , Zhang Hong-Chao , Long Kevin , Imam Senay
Published: October 2013

Diaplex MS5520, SMP Technologies, Inc. transition temperature 55°C, was filled with varying proportions (5 wt.%, 15.00 wt.%, and 25 wt.%) of magnetite nanoparticles, NanoArc and Iron(III) Oxide; 20–40 nm APS Powder from Alfa Aesar. The SMP nanocomposite was tested by thermomechanical methods, derived thermo-magnetic-mechanical methods, and shape memory methods. The results of such methods show an ability of the SMP nanocomposite to be controlled in shape deformation and recovery with an applied thermal then applied magnetic field. This paper focuses on the thermal field needed to help trigger the SMP nanocomposite. The objective of the study is to investigate the heat transfer characteristics of a SMP filled with magnetite nanoparitcles. A transient heat equation model is developed, and numerical simulation is performed in Sundance to show the underlying state of thermal change in recovery and deformation process. Result of the simulations roughly match those observed in the experiment.
A Mean-Value Model of Internal Combustion Engine Based on Variable Valve Phase Timing
Authors: Khatami S. M. Navid , Ilegbusi Olusegun J.
Published: October 2013

A simplified Mean-Value Model (MVM) is developed to represent spark ignition engine functions. The model is based on variable valve phase angle over a wide range of operating conditions. Gas exchange dynamics is simulated to determine the mass air flow into the cylinder. This flow is altered by variable valve phase mechanism. In this paper, phasing the exhaust and intake valves is considered equally (dual equal) and is equipped with hydraulics Continuous Variable Valve Timing (CVVT) mechanism. The model developed reflects these modifications and uses gas exchange dynamics to capture valve phase, manifold pressure, and engine rotating speed. The values of flow rates from this simplified mathematical model is compared and validated with engine-dynamometer experimental data. The results show strong agreement in a wide range of operating points while the variation of phase angle is limited to nominal values.
Effect of Pressure-Dependent Viscosity on the Exiting Sheet Thickness in the Calendering of Newtonian Fluids
Authors: Hernández Alfredo , Bautista Oscar E. , Bautista Eric G. , Arcos Jose C.
Published: October 2013

A theoretical model was developed to describe the calendering process in Newtonian sheets of finite initial thickness taking into account that the viscosity of the fluid is a well-defined function of the pressure. We predict the influence of the pressure effects on the leave-off distance that is related to the exiting sheet thickness in the calendering process. The mass and momentum balance equations, which are based on lubrication theory, were nondimensionalized and solved for the velocity and pressure fields by using perturbation techniques, where the leave-off distance represents an eigenvalue of the mathematical problem. When the above variables were obtained, the dimensionless leave-off distance in the calendering process was determined. Moreover, quantities of engineering interest were calculated, including the maximum pressure, the roll-separating force and the power transmitted to the fluid by the rolls. The analytical results show that the inclusion of pressure-dependent viscosity effect increases about 3.37 percent the dimensionless exiting sheet thickness or 9.4 percent the leave-off distance in comparison with the case of pressure-independent viscosity.
A Numerical Study of the Effect of an Irradiated Slatted Top Down – Bottom Up Blind on the Convective Heat Transfer Rate From a Recessed Window to an Adjacent Room
Authors: Oosthuizen Patrick H. , Paul J. T.
Published: October 2013

Top Down – Bottom Up blinds have become quite popular in recent times. However the effects of such blind systems on the convective heat transfer from the window to the surrounding room have not been extensively studied and the effect of solar irradiation of the blind on the window heat transfer has not received significant attention. The purpose of the present work was therefore to numerically investigate the effect of solar irradiation of Top Down – Bottom Up slatted blinds on this convective heat transfer. An approximate model of the window-blind system has been adopted. The solar radiation falling on the blinds is assumed to produce a uniform rate of heat generation in the blind. The Boussinesq approximation has been used. Radiant heat transfer effects have been neglected. Conditions under which laminar, transitional and turbulent flows occur have been considered. The main emphasis is on the effect of the magnitude of the irradiation and of the size of the blind openings at the top and bottom of the window on the convective heat transfer rate from the window to the room.
Enhanced Heat Capacity of Molten Salt Nano-Materials for Concentrated Solar Power Application
Authors: Devaradjane Ramaprasath , Shin Donghyun
Published: October 2013

Storage of thermal energy using molten salt materials has been widely explored for concentrating solar power. Since these power plants use thermodynamic cycle, the overall system cycle efficiency significantly relies on the thermal energy storage temperature. Therefore, increasing the thermal energy storage temperature and decreasing the amount of material needed can result in reducing the cost of solar energy. Molten salts are stable up to 700°C, relatively cheap, and safe to the environment. However, the heat capacity of the molten salts is typically low (∼1.5 J/gK) compared to other thermal storage materials. The low heat capacity of molten salts can be improved by dispersing nanoparticles. In this study, we synthesized molten salt nanomaterial by dispersing oxide nanoparticles into selected molten salts. Heat capacity measurements were performed using a modulated differential scanning calorimeter. Materials characterization studies were performed using a scanning electron microscopy. Hence, we evaluated the use of the molten salt nanomaterials as thermal energy storage media in concentrated solar power applications. Increase in the specific heat capacity of the molten salt is also demonstrated on addition with Nano materials of specific size and quantity.
Experimental Investigation of the Gas Velocities in Three Biomass Cookstoves
Authors: Castillo Thomas , Andreatta Dale A. , Guenther Dennis A.
Published: October 2013

In this study, gas velocities in different sections of three biomass cookstoves are found. A system using a Kiel probe, an electronic differential pressure transducer, and a thermocouple was used to measure pressure and temperature in order to calculate gas velocities. A Kiel probe and a sensitive electronic pressure transducer help in achieving quantifiable gas velocities. A woodgas stove, a rocket stove, and an open fire (for the purposes of this publication, an open fire is considered to be a type of stove) were tested at similar positions with respect to a cooking pot. The rocket stove and open fire used wood fuel, while the woodgas stove used pellet fuel. The gas velocity results ranged as follows: woodgas stove, 0.6 m/s to 1.56 m/s; rocket stove, 0.87 m/s to 2.88 m/s; open fire, −0.1 m/s to 1.42 m/s. The standard deviations of the velocities were mostly under 30% of the average. The ability to measure pressure and temperature simultaneously while running the stove normally can help cookstove testing and research. The goal is to not only know what stoves perform well or perform poorly, but to understand why stoves perform the way they do.
A Microfluidic Platform for Evaluating Anode Substrates for Microbial Fuel Cells
Authors: Jones A-Andrew D. , Buie Cullen R.
Published: October 2013

Microbial fuel cell technology is a new technology for producing green energy from wastewater. While lab scale and commercial microbial fuel cells typically utilize graphite as the film substrate, it is difficult to rapidly prototype micro-patterned graphite and it has not been used to date. Our design sandwiches graphite sheets under a channel layer creating a microfluidic microbial fuel cell with graphite electrodes. The microfluidic microbial fuel cell uses Geobacter sulfurreducens fed with acetate in a phosphate buffer media. Ferricyanide is used as the catholyte so that the system is anodically limited. Current versus time and open circuit voltage are reported showing biofilm growth microbial fuel cell operation.
Experimental Testing of Annular Target Surrogates for the Production of Molybdenum-99
Authors: Makarewicz Philip F. , Govindarajan Srisharan Garg , Solbrekken Gary L.
Published: October 2013

Technetium-99m (Tc-99m) is a diagnostic radiopharmaceutical that is currently used about 100,000 times daily for diagnostic imaging procedures globally [1]. The parent isotope for Tc-99m is molybdenum-99 (Mo-99), most commonly obtained through the irradiation of high enriched uranium (HEU). In accordance with the Department of Energy’s Global Threat Reduction Initiative (GTRI), an effort is underway to develop a process to produce Mo-99 using low enriched uranium (LEU). One method utilizes LEU cast in the form of a metal foil as opposed to current powder based dispersion designs for HEU. New high-volume production LEU target concepts need to be analyzed to assure safe, reliable operation during all stages of production as use of a foil requires a significant modification to the current target design.

Analytic and numeric models have been built to simulate the thermal-mechanical behavior of LEU-foil based targets under irradiation conditions. Experimental testing is being used to validate the models. Heating conditions are controlled by heater placement and cooling water circulation to place the target interfaces into controlled states of compression and tension. Thermocouples are used to measure the temperature at key locations so that the thermal contact resistance can be evaluated and compared with the predictions.
A Fundamental View of the Flow Boiling Heat Transfer Characteristics of Nano-Refrigerants
Authors: Cremaschi Lorenzo
Published: October 2013

Driven by higher energy efficiency targets and industrial needs of process intensification and miniaturization, nanofluids have been proposed in energy conversion, power generation, chemical, electronic cooling, biological, and environmental systems. In space conditioning and in cooling systems for high power density electronics, vapor compression cycles provide cooling. The working fluid is a refrigerant and oil mixture. A small amount of lubricating oil is needed to lubricate and to seal the sliding parts of the compressors. In heat exchangers the oil in excess penalizes the heat transfer and increases the flow losses: both effects are highly undesired but yet unavoidable.

This paper studies the heat transfer characteristics of nanorefrigerants, a new class of nanofluids defined as refrigerant and lubricant mixtures in which nano-size particles are dispersed in the high-viscosity liquid phase. The heat transfer coefficient is strongly governed by the viscous film excess layer that resides at the wall surface. In the state-of-the-art knowledge, while nanoparticles in the refrigerant and lubricant mixtures were recently experimentally studied and yielded convective in-tube flow boiling heat transfer enhancements by as much as 101%, the interactions of nanoparticles with the mixture still pose several open questions. The model developed in this work suggested that the nanoparticles in this excess layer generate a micro-convective mass flux transverse to the flow direction that augments the thermal energy transport within the oil film in addition to the macroscopic heat conduction and fluid convection effects. The nanoparticles motion in the shearing-induced and non-uniform shear rate field is added to the motion of the nanoparticles due to their own Brownian diffusion. The augmentation of the liquid phase thermal conductivity was predicted by the developed model but alone it did not fully explain the intensification on the two-phase flow boiling heat transfer coefficient reported in previous work in the literature. Thus, additional nano- and micro-scale heat transfer intensification mechanisms were proposed.
The Exact Calculation of the Added Resistance in Waves
Authors: Zangeneh Razieh , Ghiasi Mahmood , Baygloo Mahdi Ghareh , Yan Terry
Published: October 2013

The exact calculation of the added resistance in waves is a seakeeping problem of high interest due to economic effect on ship exploitation. In this paper an open uniform B-spline based method is developed to calculate added resistance. Initially this method applied to calculate velocity potential and Kochin functions that are necessary for calculation of the added resistance by Kashiwagi’s formula. For this purpose the source strength and potential are distributed over body surface and described Open-uniform B-spline basic function. Computations are performed for different hull forms then results are validated by comparing them with practical results. The present method shows a good agreement in contrast to published results.
Wireless Multi-Sensor Integration for ACL Rehabilitation Using Biofeedback Mechanism
Authors: Senanayake S. M. N. Arosha , Malik Owais Ahmed , Iskandar Mohammad
Published: October 2013

The objective of this study is to propose an integrated motion analysis system for monitoring and assisting the rehabilitation process for athletes based on biofeedback mechanism, particularly for human subjects already undergone Anterior Cruciate Ligament (ACL) injury operations and thus about to start the rehabilitation process. For this purpose, different types of parameters (kinematics and neuromuscular signals) from multi-sensors integration are combined to analyze the motion of affected athletes. Signals acquired from sensors are pre-processed in order to prepare the pattern set for intelligent algorithms to be integrated for possible implementation of effective assistive rehabilitation processing tools for athletes and sports orthopedic surgeons. Based on the characteristics of different signals invoked during the rehabilitation process, two different intelligent approaches (Elman RNN and Fuzzy Logic) have been tested. The newly introduced integrated multi-sensors approach will assist in identifying the clinical stage of the recovery process of athletes after ACL repair and will facilitate clinical decision-making during the rehabilitation process. The use of wearable wireless miniature sensors will provide an un-obstructive assessment of the kinematics and neuromuscular changes occurring after ACL reconstruction in an athlete.
Optimization of Large Wind Farms Using a Genetic Algorithm
Authors: Mittal Anshul , Taylor Lafayette K.
Published: October 2013

Optimizing the placement of the wind turbines in a wind farm to achieve optimal performance is an active area of research, with numerous research studies being published every year. Typically, the area available for the wind farm is divided into cells (a cell may/may not contain a wind turbine) and an optimization algorithm is used. In this study, the effect of the cell size on the optimal layout is being investigated by reducing it from five rotor diameter (previous studies) to 1/40 rotor diameter (present study).

A code is developed for optimizing the placement of wind turbines in large wind farms. The objective is to minimize the cost per unit power produced from the wind farm. A genetic algorithm is employed for the optimization. The velocity deficits in the wake of the wind turbines are estimated using a simple wake model. The code is verified using the results from the previous studies. Results are obtained for three different wind regimes: (1) Constant wind speed and fixed wind direction, (2) constant wind speed and variable wind direction, and (3) variable wind speed and variable wind direction. Cost per unit power is reduced by 11.7% for Case 1, 11.8% for Case 2, and 15.9% for Case 3 for results obtained in this study. The advantages/benefits of a refined grid spacing of 1/40 rotor diameter (1 m) are evident and are discussed.

To get an understanding of the sensitivity of the power produced to the wake model, optimized layout is obtained for the Case 1 using a different wake model.
Viscoelasticity Analysis and Experimental Validation of Anisotropic Composite Overwrap Cylinders
Authors: Tzeng Jerome T. , Emerson Ryan P. , O’Brien Daniel J.
Published: October 2013

Stress relaxation and creep of composite cylinders are investigated based on anisotropic viscoelasticity. The analysis accounts for ply-by-ply variation of material properties, ply orientations, and temperature gradients through the thickness of cylinders subjected to mechanical and thermal loads. Experimental validation of the model is conducted using a high-tensioned composite overwrapped on a steel cylinder. The creep and stress relaxation response of composite is accelerated at elevated temperatures, then characterized and compared to the model simulation. Fiber reinforced composite materials generally illustrate extreme anisotropy in viscoelastic behavior. Viscoelastic effects of the composite can result in a drastic change of stress and strain profiles in the cylinders over a period of time, which is critical for structural durability of composite cylinders. The developed analysis can be applied to composite pressure vessels, gun barrels, and flywheels design of life prediction.
Flexible Photonics Based Optofluidic Photobioreactors
Authors: Jung Erica Eunjung , Erickson David
Published: October 2013

In this work we demonstrate a novel optofluidic photobioreactor that can help address two major challenges in algae derived biofuel production. For the first time, we have demonstrated and characterized the growth of photosynthetic organisms (S. elongatus) using the evanescent field on a slab waveguide. We also have demonstrated that the energy efficiency of evanescent field illumination is at least as efficient as the direct illumination method used in current photobioreactors. The stackable structure of our photobioreactor may allow 12 fold improvement in the volumetric productivity compared to the direct illumination method.
Hydrodynamic and Heat Transfer Effects of Different Sparger Spacings Within a Column Photobioreactor Using Computational Fluid Dynamics
Authors: Bari Ghazi S. , Gent Stephen P. , Suess Taylor N. , Anderson Gary A.
Published: October 2013

An important factor in designing photobioreactors is appropriate selection of sparger geometry and placement. The sparger governs the bubble size distribution and gas hold-up. These factors in turn influence flow pattern, effective interfacial area, rates of mass transfer, heat transfer, and mixing. This project investigates the effects of sparger geometry and placement on bubble and fluid flow patterns and convective heat transfer within a column photobioreactor (PBR) using Computational Fluid Dynamics (CFD). Experimental and computational studies have been completed that focused on the hydrodynamics and heat transfer within a rectangular column photobioreactor (34.29 cm long × 15.25 cm wide × 34.29 cm tall) with a single sparger located at the center of its base (33.02 cm × 1.27 cm) running lengthwise. Similar studies have also been completed analyzing a full width sparger on the bottom of the PBR similar to a porous membrane sparger. This study extends previous work by investigating the flow patterns and heat transfer effects due to multiple rows of spargers at different spacings running perpendicular to the length of the PBR. Comparison of hydrodynamic and heat transfer parameters are made for the different types of spargers at different volumetric flow rates. The gas bubbles and the water-based media within the photobioreactor are modeled using the Lagrangian-Eulerian approach. A low Reynolds k-Epsilon turbulence model is used to predict near-wall flow patterns. The main interaction forces between the bubbles and the media, including drag forces, added mass forces, and lift forces, are considered. The overarching goal of this research is to improve PBR designs, thus enhancing microalgae production for biofuel and bioproducts production. It is hypothesized that changing the spacing of the PBR spargers will alter the bubble flow patterns. Despite its importance, optimizing the sparger geometry and placement in PBRs for microalgae production is still largely not understood. In this study, simulation results are presented for various sparger spacings, which can be helpful in designing sparger geometry and placement for maximized microalgae production.
Optimization of Wind Turbine Array Performance in Offshore Wind Farms
Authors: Li Simeng , Alexander J. Iwan D.
Published: October 2013

An improved program of previous optimization work is put forward for analyzing and optimizing the spatial configurations of wind turbines in offshore wind arrays. It applies Ainslie’s wake model in which the wake profile is dependent on wind speed, turbulence intensities and the turbine’s thrust coefficient. Models of single wakes and multiple wakes are employed. Weibull distributions and turbulence intensities of wind are applied. A real wind turbine power curve is used to estimate power out of the turbines. The annual power output of the wind array for the North Sea’s Horns Rev wind array is evaluated and compared with the optimization results. Disagreement is observed between the simulated results using different angular discretizations of the possible wind directional probabilities. An analysis and possible explanation are discussed.
Power Reclamation Efficiency of a Miniature Energy Harvesting Device Using Internal Fluid Flows
Authors: Çıkım Taha , Tatar Oğuz , Koşar Ali , Gözüaçık Devrim
Published: October 2013

This study comprises experimental energy harvesting results of a miniature internal liquid flow power reclamation device. The system’s reclamation principal is basically related to translation of mechanical energy and its conversion into electrical energy. The translation phase is concerned about capturing vibrations caused in the device by inner liquid flow via device tails, which are designed by taking inspiration from black ghost knife fish (Apteronotus albifrons) body shape. On the other hand, the conversation phase is attained by the rotating movement of the mentioned tails so that the rotating circular waterproof magnet structure could yield power through magnetic polarization. A simple current amplifier increases the voltage obtained, and the reclaimed power is transferred to the 3.76V (Ni-Mg) batteries. The efficiency tests were performed within a range of flow velocities (1.0 m/s ∼ 5.0 m/s) under various fluid densities (fresh water, low dense and high dense water) and different ambient temperatures (22 and 38 °C) in order to obtain a comparative parametric data about the device response to internal fluid flow. In optimum test conditions (fresh water as working fluid and 38°C ambient temperature) the device harvested up to 17, 26 Watts of energy.