bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis Method for CFD Results of Centrifugal Blower in Vacuum Cleaner Using Proper Orthogonal Decomposition
Authors: Sato Koma , Honda Takeshi
Published: March 2016

2D and steady analysis have been replaced by 3D and unsteady analysis because of dramatic improvements in computational environments. Analysis models that faithfully simulate actual products conventionally tend to be complicated and large scale. Therefore, the storage of analysis results has been increasing tremendously, and the dominant flow-field structure has been difficult to clarify. Data reduction by proper orthogonal decomposition (POD) is effective for simultaneously reducing the number of results of unsteady computational fluid dynamics (CFD) and for comprehending the dominant flow-field structure. However, only a few applications are used in the domain of industrial machinery. In this study, we applied the POD method to unsteady CFD results of a centrifugal blower in a vacuum cleaner and evaluated the benefits.

We extracted a time series of static pressure distribution in the diffuser from unsteady CFD results corresponding to one rotation of the impeller, applied the POD to these data, and compared the results of an experiment. The results were that the first six modes had a 99.4% contribution in terms of the L2 norm. In the scope of this research, the first six modes were revealed to surrogate the pressure fluctuation sufficiently. Also, the data storage was reduced to less than 2.0% of the original unsteady results. Next, frequency spectra were obtained by applying a discrete Fourier transform (DFT) to the expansion coefficients. The spectra of the expansion coefficients of the POD modes were found to have a peak near the blade passing frequencies (BPFs). The noise, the frequency of which is BPF, causes the majority of the noise that occurs in the diffuser. Therefore, we found by using both the POD and DFT that we could both reduce the dramatic data storage and extract the flow-field structures.
Study on Acoustic Analysis of a Glass Window by BEM and FEM
Authors: Tanimoto Hiroyuki , Morimoto Yoshitaka , Takasugi Keigo
Published: March 2016

This research employed acoustic analysis software and established an analytical method for sound transmission loss, which is a sound-insulation performance measure for glass windows. In addition to prediction of transmission loss through vibration of the glass, the research estimated acoustic characteristics that considered transmission loss in the vibration of the frame. Acoustic analysis was conducted with 3D CAD for glass windows of 8 mm plate thickness through preparation of an analysis model under the same conditions as a vibration test. The acoustic analysis also considered both the glass pane and aluminum frame on the side of the sound source. This paper evaluated the results based on analytical values and experimentally observed values.
Design of Centrally Supported Biomimetic MEMS Microphone for Acoustic Source Localization
Authors: Ishfaque Asif , Kim Byungki
Published: March 2016

Biologically inspired unique perforated diaphragm architecture for acoustic source localization has been designed. The merely 500 μm separated structure of ears of fly Ormia ochracea which increases the interaural time and intensity differences of arriving sound has great ability to enhance the acoustic source localization. This remarkable capacity of fly to amplify direction cues for incoming sound along with squeeze film damping effects are the key inspirations for designing the diaphragm. In this design, we maintain a unique ratio between the number of holes and the diaphragm size and enhanced the acoustic directional sensitivity cues. A mechanical structure based on the ears of fly Ormia ochracea is modeled and the response is observed on different frequencies by considering the critical damping value and also on zero damping value. In one step further a perforated diaphragm is designed utilizing ANSYS software and is examined with fluid elements to estimate the damping value. A harmonic analysis is carried out in conjunction with estimated damping value 0.3325 and also on zero damping value. The figured results are very much similar to the modeled results and a range of 1 nm to 472 nm amplitude differences between two sides of the diaphragm is observed over the entire range of the frequency in damping case.
An Elitist Ants-Search Based Method for Optimum Synthesis of Rigid-Linkage Mechanisms
Authors: Diab Nadim , Smaili Ahmad
Published: March 2016

Mechanical linkages are widely used in the industry and the synthesis of such mechanisms may require optimization depending on the number of precision positions required. Many intelligent optimization techniques (Genetic, Tabu, Simulated Annealing, etc) have been proposed in the literature, one of them being the Ant-Search which was first proposed by the authors in 2007. In this paper, a Modified Ant-Search (MAS) technique is proposed to optimize the synthesis of a four-bar mechanism with a path generation task. Two major improvements are applied over the previous algorithm: ants pheromone update and exploration/exploitation techniques are both modified. Unlike the previous work where a constant quantity of pheromones was added during each iteration, in this paper, the pheromone deposit rate is proportional to the error of the objective function. Such a modification in the pheromone update rule is expected to differentiate between the behaviors of different ants and better govern their motion in the subsequent iterations. Moreover, the second major improvement targets the exploration/exploitation techniques followed by the ants. Unlike the previous work where exploration dominates during the early iteration stages and exploitation during the late ones, this work implements a more dynamic strategy where ants enter and leave the exploration/exploitation processes as governed by parameters related to the objective function error and pheromone deposit levels. Such modifications applied to the Ant-Search (AS) technique are expected to ensure a better chance of converging to a global minimum. The MAS technique is applied for a few path generation tasks with prescribed timing along with a set of linear constraints. Results are compared with previous work in the literature where the newly proposed technique showed appreciable improvement as evaluated by the structural error objective function. Future work possibilities are also introduced.
Shape Optimization of Clutch Cushion Disc Using Differential Evolution Method
Authors: Kaya N. , Kartal S. , Çakmak T. , Karpat F. , Karaduman A.
Published: March 2016

The clutch is an element which makes a temporary connection between gear box and vehicle engine. It transmits not only engine torque, but also ensures comfort and drivability during slippage. One of the main functions of clutch disc is to transmit the engine torque while absorbing vibrations. It allows a soft gradual reengagement of torque transmission. The cushion disc which is located between two clutch facings has wavy surface, thus it behaves like a spring during engagement and disengagement. The axial elastic stiffness of the clutch disc is obtained by a cushion disc. The load-deflection curve is obtained by compressing clutch disc between two plates, representing pressure plate and flywheel. The wavy shape of the cushion disc provides progressive stiffness curve of the clutch disc.

The cushion disc participates in drivers comfort during engagement of the clutch. The comfort depends on the limits of the progressive stiffness curve. Outside the limits of this cushion function, the clutch engagement would be harsh and uncomfortable for the driver. Besides, engine torque may not be transmitted during the later service lifetime and the life of the clutch might be decreased. In the case cushion disc has no cushioning function, then the engine might be stopped. Additionally, improper cushioning function causes heat and deform of the pressure plate and it also decreases the transmitted engine torque. Therefore, cushion disc has to have certain cushioning characteristics in order to overcome these problems.

In this study, the optimum shape design of cushion disc was performed using an evolutionary optimization algorithm. Differential evolution algorithm was selected as the optimization method because it guarantees the global optimum. Design of experiment method has been employed to construct the response surface that approximates the behavior of the objective function inside a certain design space. Three shape parameters of cushion disc have been selected. The objective of the shape optimization is to find the optimum shape parameters that provide the target stiffness curve. After solving the optimization problem with differential evolution method, optimum shape parameters of cushion disc have been found for two case studies. A Pascal code based differential evolution optimization code was developed for shape optimization and Ansys finite element software was used for calculating stiffness curve of cushion disc.
Analysis of ‘Kana-Ami’ Structure Between Expert and Non-Expert by Using X-Ray Computed Tomography (CT)
Authors: Zelong Wang , Tsuji Ken-ichi , Tsuji Toru , Takai Yuka , Goto Akihiko
Published: March 2016

‘Kana-ami’ is a kind of metal wire network in Japan. This study aimed to focus on ‘Kana-ami’ technique development in order to keep this culture wealth and skill to the next generation. In this study, the two participants were selected for comparison called as expert and non-expert. The products made by participants were scanned by X-ray computed tomography precisely. The distance between two metal wires of ‘Right-line’ and ‘Left-line’ was calculated. The compression test also was performed to clarify the performance of final products. The expert’s product was shown smaller damage on the surface of Tofu in the end.
Solid Fuel Fire Behavior Under Fixed Pressure in a Low-Pressure Chamber
Authors: Feng Rui , Liu Quanyi , Tian Runhe , Chen Kewei , Yang Rui , Zhang Hui
Published: March 2016

To comprehensively reveal the difference of solid fuel fire characteristics at different altitudes, fire experiments of cardboard boxes at multiple static pressures with two configurations filled with shredded office paper were conducted in a low-pressure chamber. The measured parameters are mass burning rate, radiative heat flux, oxygen concentration and heat release rate (HRR) etc. The mass burning rate divided by fire base dimension ṁ/D is correlated against the production of pressure-squared times length-cubed (P2L3) to the power of 0.29 based on current cardboard boxes fire test data. HRR of two boxes fire tests are higher than that of one box fire tests under fixed pressures. However, there are a higher peak of HRR under a fixed higher pressure for one-box fire tests while a lower peak of HRR under a higher pressure for two-box fire tests. The HRR would decrease sharply after reaching the peak.
Stability Prediction of Milling Process With Closed Machining System Dynamics With Flexible Thin-Walled Workpiece
Authors: Xu Chao , Feng Pingfa , Yu Dingwen , Wu Zhijun , Zhang Jianfu
Published: March 2016

Despite recent advances and improvements in modeling and prediction of the dynamics of the machining process, an efficient machining process is limited due to chatter and instability of machining system. In fact, the machining system contains various kinds of joints, which cause difficulties in dynamics modeling, simulation and prediction. Moreover, the flexible support system results in large deformation and violent vibration of the workpiece when machining, and the thin-walled workpiece easily gives rise to the chatter of the machining system. Therefore, the dynamics of the flexible support system was considered to calculate stability lobe diagram in the modeling of milling process. The whole machining system was regarded as a closed loop composed by the machine tool structures, support, workpiece and machining process. In this paper, the receptance coupling (RC) method was introduced to predict the dynamics of the closed machining system. A milling process was taken for example to predict the chatter limitations using the dynamics of closed model. The mathematical model of the machining system (machine tool structures, spindle, holder and tool), together with the details of joint contacts, was given based on the RC method. The RC model was used to obtain the dynamics of the system, while receptance of the tool point was coupled. Based on the coupling model of the machining system, the depth limitations under different speeds were estimated for the technology parameter optimization in milling process. The response was considered to be the sum of the cutting point and the support system. The flexibility of the support system was considered to be the feedback of the cutting stiffness. By this means, the traditional model was modified to calculate the stability lobe diagram based on the dynamics of the spindle and support system. Furthermore, the milling experiment was carried out to verify the prediction results, and the dominant natural frequencies of receptance at tool point were obtained by modal testing to define the stability lobe diagram. It was found that the chatter results matched well with the stability lobes. It was concluded that the support system with poor stiffness might cause violent chatter especially when the workpiece was thin-walled. The cutting depth limitations of the flexible support system were lower than that of the rigid one. Moreover, this closed model of the machining system is appropriate for the chatter prediction of the flexible support system or thin-walled workpiece, so it is helpful for a better parameter optimization.
Study on a Cell Mechanosensing System by Measuring Structural Deformation and Biochemical Response
Authors: Horiguchi Atsushi , Shiraishi Toshihiko
Published: March 2016

Mechanical stimulation induces new bone formation in vivo and promotes the metabolic activity and the gene expression of osteoblasts in vitro. It was reported that biochemical signals of osteoblasts to sense mechanical stimulation are activated according to their actin cytoskeletal deformation. However, there have been not so many researches on the relationship between cytoskeletal deformation and biochemical response. Here we show an original method to investigate a cell mechanosensing system and the quantitative relationship between the deformation of cytoskeletal structure and the change of intracellular calcium ion concentration as biochemical response in a living cell stimulated by a micropipette. Gene transfection of green fluorescent protein to osteoblastic cells enabled visualization of actin in cells. When local deformation was applied to a single osteoblastic cell by a micropipette, the displacement distribution of cytoskeletal structure in the whole cell was automatically obtained from the two images of the cell before and after deformation by using Kanade-Lucas-Tomasi (KLT) method. Intracellular calcium ion response to mechanical stimulation was measured as the spatial and temporal changes of intensity of Fura Red loaded to a cell. As a result, we obtained the quantitative relationship between structural deformation and biochemical response of a cell and found that the change of calcium ion concentration increases with increasing the displacement of actin cytoskeleton. It indicates that the deformation of actin cytoskeleton is highly related to the cell mechanosensing system.
A Smart Method for Developing Game-Based Virtual Laboratories
Authors: Zhang Zhou , Zhang Mingshao , Chang Yizhe , Esche Sven K. , Chassapis Constantin
Published: March 2016

Virtual laboratories are one popular form of implementation of virtual reality. They are now widely used at various levels of education. Game-based virtual laboratories created using game engines take advantage of the resources of these game engines. While providing convenience to developers of virtual laboratories, game engines also exhibit the following shortcomings: (1) They are not realistic enough. (2) They require long design and modification periods. (3) They lack customizability and flexibility. (4) They are endowed with limited artificial intelligence. These shortcomings render game-based virtual laboratories (and other virtual laboratories) inferior to traditional laboratories.

This paper proposes a smart method for developing game-based virtual laboratories that overcomes these shortcomings. In this method, 3D reconstruction and pattern recognition techniques are adopted. 3D reconstruction techniques are used to create a virtual environment, which includes virtual models of real objects and a virtual space. These techniques can render this virtual environment fairly realistic, can reduce the time and effort of creating the virtual environment and can increase the flexibility in the creation of the virtual environment. Furthermore, pattern recognition techniques are used to endow game-based virtual laboratories with general artificial intelligence. The scanned objects can be recognized, and certain attributes of real objects can be added automatically to their virtual models. In addition, the emphasis of the experiments can be adjusted according to the users’ abilities in order to get better training results. As a prototype, an undergraduate student laboratory was developed and implemented. Finally, additional improvements in the approach for creating game-based virtual laboratories are discussed.
Implementation of Finite Height Levee in CaFunwave Using an Immersed Boundary Method
Authors: Oler Adam M. , Zhang Ning , Brandt Steven R. , Chen Qin J.
Published: March 2016

Hydrodynamic simulations of storm-surge waves on coastal structures are essential for coastal areas in predicting wave and flood damages. In a large scale regional model, the coastal structures, such as networks of coastal highways, floodgates and levees, are often complex in shapes. In addition, the width of those structures are smaller in size compared to the grid sizes which in the ranges of 10s to 100s meters. Therefore, in hydrodynamic simulations, it is not possible to use body fitted mesh to conform with the shapes of those networks due to the complicated shapes, and it is very expensive to resolve these small scale structures with very fine grid resolutions. The Immersed Boundary Method (IBM) allows for overcoming these difficulties with an accurate but less expensive way. Since the structures were represented by immersed boundary (IB) points which do not have to be collocated with grid points, complicates shapes structures and the structures smaller than grid resolutions can be realized, and simple Cartesian grids can be utilized without sacrificing accuracy. In a previous study by the authors, an infinite height floodgate/levee structure has been implemented using an IBM which the IB force terms were added in both u and v equations while no IB force term in z (water-elevation) equation. In this study, the height effect was added to the previous developed model. It is worth mentioning that the background flow model is a 2-D depth-averaged shallow water flow model, and the height effect is not implemented by a 3-D mesh. Instead, it is implemented by adding the IB force to the water-elevation equation. The feedback-force type of IBM was used in this study because of its superior performance on this type of simulations compared to the counterpart direct-forcing IBM as shown in the author’s previous publication. In this study, the CaFunwave package was used as the background flow solver, and the IB implementation was written into an separate function incorporated to the package. The equations solved in CaFunwave are the fully nonlinear Boussinesq-type equations, which are capable of modeling of near-shore hydrodynamics. The original model of CaFunwave is FUNWAVE-TVD. In this paper, constant height and non-constant height floodgates/levees were implemented in the simulations. Non-constant height represents broken floodgate/levee situations that parts of the structure are collapsed. The results of one constant-height gate simulation were compared to the results of a simulation that a finite height gate that was constructed directly from the topography data for validation. The floodgate/levee height and shape effects on the flows and waves were revealed from the simulation results.
A Thermodynamic Analysis of the Temperature Drop and Potential Cooling Effect of Cavitation
Authors: Alkotami Abdulmalik , Beck B. Terry , Sorensen Christopher M. , Hosni Mohammad H. , Eckels Steven J. , Tomasi Don
Published: March 2016

The main objective of this paper is to evaluate the temperature drop and potential cooling effect due to cavitation of an arbitrary liquid. Cavitation results from a pressure decrease into the metastable liquid region, to the point where some of the liquid nucleates (boils). Under adiabatic conditions, the energy required to produce this phase change is pulled from the fluid itself, which results in a temperature drop.

The paper discusses the fundamental thermodynamics associated with the temperature drop in an effort to better understand the cooling process and to identify of the optimum fluid capable of developing significant cooling results.

The analysis presented here focuses on a general Equation of State (EOS), to represent an arbitrary fluid. At a given temperature, such an EOS yields a relationship between pressure and density (or specific volume). The van der Waals EOS was used initially to define the saturated liquid and saturated vapor lines, for water, R134a, R22 and R123. Work later focused on the Peng Robinson EOS, which better represents the properties of a wide variety of substances. The Peng Robinson EOS was used to investigate different fluids such as water, R134a, R22 and R123. The principle of corresponding states was introduced, to express the thermodynamic variables in terms of reduced (or relative) state variables. Coexistence curves and spinodal curves were determined numerically. This stems from the unique values of the acentric factor for each fluid.

A basic theory was then formulated using the Peng Robinson EOS to determine the maximum temperature reduction. ΔTmax, which will occur if the cavitation phase transition occurs adiabatically. Variables that affect this maximum temperature drop are identified are shown to include latent heat of vaporization, specific heat, and “equivalent quality” at the spinodal line limit.

Further analysis of the temperature drop as a function of reduced pressure was investigated for water, R134a, R123, and R22, and reveals that an apparent optimum (or maximum) temperature drop is achieved for a general fluid when the reduced pressure equals approximately 0.5.
Experimental Characterization of the Combustion Process of Briquettes From Corn Cob and Coconut Fibers Residues
Authors: Díaz Ávila William Yesid , Nova Casares Víctor Antonio , Ávila Gómez Adrián Enrique , Gómez Vásquez Rafael David , Arrieta Almario Álvaro Ángel
Published: March 2016

This study presents the experimental combustion characteristics of biomass briquettes made from agricultural wastes (coconut fiber and corn cob) of Córdoba-Colombia. For this thermochemical conversion, the actual heat transfer during the process and the main combustion characteristics are also studied. Initially, several corncob and coconut fibers briquettes were produced and burned. The non-adiabatic flame temperatures and the air velocity were measured. To study the combustion process dynamics, a process simulation was performed in EES Software© using the typical mass balances of a combustion process, and taking into account the possible stoichiometric equation, using as input the elemental analyzes of each biomass and the excess air that was determined experimentally. The exhaust gases and completeness combustion with moist air were evaluated and usual combustion parameters and correlations like energy balance, enthalpy of formation of the exhaust gases and process exergy were calculated. Likewise, the heat transfer by convection, radiation and heat flow at the gas outlet was evaluated, referenced to the process temperatures. It was found that values of non-adiabatic flame temperature were around 500 ° C, while surface and gases temperatures were between 60–81 ° C and 60 ° C respectively. In general, low emissions of harmful gases to the atmosphere were generated during the combustion of these briquettes. As well, the energy availability at the outlet can be used for moderate heating processes. These findings make these types of biomass a viable alternative to be utilized as renewable energy source.
Thermoeconomic Analysis of Wheat Flour Agroindustrial Plant
Authors: Fajardo J. , Sarria B. , Castellon L. , Barreto D.
Published: March 2016

This paper presents the development of an exergy and thermoeconomic analysis of a wheat flour agro-industrial plant, which was aimed to evaluate the energy use and establish the operation cost of its components, and to understand the cost formation process and the cost flow. It was found that throughout the production process exists an exergy destruction ratio of 95,08 %. It identified improvement opportunities in relation to cost, has recommended alterations with regard matter flows or an economic investment for change some components with low exergoeconomic factors: 2% planer of wheat bran, 3% knurled roller grinding benches and 5% smooth roller grinding benches.
Effects of Design Parameters on Aerodynamic Performance of New Profile Small Wind Turbine Blades
Authors: Birajdar Mahasidha , Kale Sandip , Sapali S. N.
Published: March 2016

Wind is a one of the clean resources of energy and has the ability to contribute a considerable share in growing world energy consumption. The small wind turbine plays a vital role in fulfillment of energy needs preferably for household purpose. In order to unleash the budding of applicability of small wind turbine, it is necessary to improve its performance. The performance of a small wind turbine can be distinguished by the manners in which power, thrust and torque vary with the wind speed. The wind power indicates the amount of energy captured by the wind turbine rotor. It is convenient to express the performance of small wind turbine by means of non-dimensional performance curves, therefore in this paper the most graphs are drawn to power, thrust and torque coefficients as a function of the tip speed ratio. This paper presents the effect of design parameters such as the tip speed ratio, angle of attack, wind speed, solidity, number of blades, etc. on the aerodynamic performance of small wind turbine and proposes the optimum values of these parameters for the newly designed blade. The new designed blade consists of two new airfoils and named as IND 15045 and IND 09848. This new profile blade is designed for a wind turbine of 1 kW rated power. The blade is divided into ten sections. The designed length of blade is 1.5 m and it is made using IND 15045 airfoils at three root sections and IND 09848 airfoils for remaining seven sections. Q-Blade is used for the numerical simulation of wind turbine airfoils and blade. It is integrated tool of XFOIL and blade element momentum theory of wind turbine blade design. Also the effect of constant rotational speed operation, effect of stall regulation effect of rotational speed change and the effect of solidity on the performance of wind turbine is discussed. This paper delivers a broad view of perception for design of small wind turbine and parameter selection for the new wind turbine blade. Also in this paper the effect of different losses viz. tip losses, drag losses, stall losses and hub losses on the small wind turbine are discussed. The efficiency of the small wind turbine varies significantly with wind speed, but it would be designed such a way that maximized efficiencies are achieved at the wind speed where the maximum energy is available.
The Boundary Integral Method Applied to Non-Spherical Cavitation Bubble Growth and Collapse Close to a Rigid Boundary
Authors: Alhelfi Ali , Sunden Bengt
Published: March 2016

Recently much attention has been paid to studies concerning bubble dynamics in the cavitation phenomena and this topic has been the subject of many research works. In fact, the simulation of non-spherical bubble dynamics and its interaction with solid boundaries have received much less attention due to the complexity of the problem. One of the main reasons of the structural damages in the cavitation phenomenon is due to the formation of micro jets generated due to the bubble collapse and impinging on the solid surfaces or boundaries.

The boundary integral method (BIM) based on Green’s function is used to model the oscillation and collapse of a cavitation bubble close to a rigid boundary. The liquid is considered to be incompressible, inviscid, and irrational around the bubble. These assumptions satisfy the conditions for the Laplacian equation.

The theory permits one to predict correctly the interaction between the bubble and the rigid boundary, which is of great importance in the study of cavitation damage due to a bubble collapsing close to the boundaries. The results reveal that the amplitude of bubble oscillation depends on the bubble location away from a rigid surface. Also, the theory for the cavitation bubble dynamics presented in this study has many advantages in various situations and might be helpful to understand effects of the cavitation phenomenon such as generation of excessive vibration, surface erosion and undesirable acoustic emission.
An Ignition Delay Study of Category A and C Aviation Fuel
Authors: Min Kyungwook , Valco Daniel , Oldani Anna , Lee Tonghun
Published: March 2016

Ignition delay of category A and C alternative aviation fuels have been investigated using a rapid compression machine (RCM). Newly introduced alternative jet fuels are not yet comprehensively understood in their combustion characteristics. Two of the category C fuels that will be primarily investigated in this study are Amyris Farnesane and Gevo Jet Fuel Blend. Amyris direct sugar to hydrocarbon (DSHC) fuel (POSF 10370) come from direct fermentation of bio feedstock sugar. Amyris DSHC is mainly composed of 2,6,10-trymethly dodecane, or farnesane. Gevo jet blend stock fuel is alcohol to jet (ATJ) fuel (POSF 10262) produced from bio derived butanol. Gevo jet blend stock is composed with iso-dodecane and iso-cetane, and has significantly low derived cetane number of 15. The experimental results are compared to combustion characteristics of conventional jet A fuels, including JP-8. Ignition delay, the important factor of auto ignition characteristic, is evaluated from pressure trace measured from the RCM at University of Illinois, Urbana-Champaign. The measurements are made at compressed pressure 20bar, intermediate and low compressed temperature, and equivalence ratio of unity and below. Direct test chamber charge method is used due to its reliable reproducibility of results. Compared to category A fuels, different combustion characteristics has been observed from category C fuels due to their irregular chemical composition.
Performance Estimation of Direct Methanol Fuel Cell Using Artificial Neural Network
Authors: Biswas M. A. Rafe , Robinson Melvin D.
Published: March 2016

A direct methanol fuel cell can convert chemical energy in the form of a liquid fuel into electrical energy to power devices, while simultaneously operating at low temperatures and producing virtually no greenhouse gases. Since the direct methanol fuel cell performance characteristics are inherently nonlinear and complex, it can be postulated that artificial neural networks represent a marked improvement in performance prediction capabilities. Artificial neural networks have long been used as a tool in predictive modeling. In this work, an artificial neural network is employed to predict the performance of a direct methanol fuel cell under various operating conditions. This work on the experimental analysis of a uniquely designed fuel cell and the computational modeling of a unique algorithm has not been found in prior literature outside of the authors and their affiliations. The fuel cell input variables for the performance analysis consist not only of the methanol concentration, fuel cell temperature, and current density, but also the number of cells and anode flow rate. The addition of the two typically unconventional variables allows for a more distinctive model when compared to prior neural network models. The key performance indicator of our neural network model is the cell voltage, which is an average voltage across the stack and ranges from 0 to 0:8V. Experimental studies were carried out using DMFC stacks custom-fabricated, with a membrane electrode assembly consisting of an additional unique liquid barrier layer to minimize water loss through the cathode side to the atmosphere. To determine the best fit of the model to the experimental cell voltage data, the model is trained using two different second order training algorithms: OWO-Newton and Levenberg-Marquardt (LM). The OWO-Newton algorithm has a topology that is slightly different from the topology of the LM algorithm by the employment of bypass weights. It can be concluded that the application of artificial neural networks can rapidly construct a predictive model of the cell voltage for a wide range of operating conditions with an accuracy of 10−3 to 10−4. The results were comparable with existing literature. The added dimensionality of the number of cells provided insight into scalability where the coefficient of the determination of the results for the two multi-cell stacks using LM algorithm were up to 0:9998. The model was also evaluated with empirical data of a single-cell stack.
Robust Anti-Swing Adaptive Fuzzy Tracking Control for Tower Crane Systems With Both Dead-Zone Band and Time-Delays Uncertainties
Authors: Wu Tzu Sung , Karkoub Mansour
Published: March 2016

Complex mechanical systems, such as tower cranes, are known to be highly nonlinear, under-actuated, and non-colocated, which makes their closed-loop control very challenging. The interconnected components of these systems undergo complex dynamic phenomena, such as friction, which lead to energy or momentum transmission delays. The complexity of such systems is further complicated by external disturbances and nonlinearities resulting from using hydraulic and/or electrical actuators, mechanical joints, gears, etc., which result in the formation of dead-zones, backlash, and hysteresis. A dead-zone, which constitutes a significant non-smooth nonlinearity, severely limits the performance of many mechanical systems such as the tower crane. Previous works on the control of tower cranes were based on accurate determination of their actuated states. In this work, a robust control technique based on adaptive fuzzy theory is investigated for anti-swing and trajectory tracking of tower crane systems. The system is subject to uncertainties in parameter parameters, time delays, external disturbances, and unknown actuator nonlinearities. The unknown actuator nonlinearities, from the jib and tower motors, are characterized by dead-zone bands (as opposed to the typical crisp dead-zone functions). First, fuzzy logic systems with on-line adaptations are utilized to evaluate the unknown nonlinear functions. The proposed control scheme uses the H∞ control technique to develop compensators to overcome the effects of parameter variations, time delays, external disturbances, and unknown actuator dead-zone band nonlinearities. The proposed control scheme ensures the stability of the closed-loop system and achieves desired tracking precision such that the states of the tower crane system are ultimately uniformly bounded (UUB) and guarantees an H∞ norm bound constraint on disturbance attenuation for all admissible uncertainties based on the Lyapunov criterion. Simulation results show the validity of this approach for the tower crane system.
Structural, Mechanical and Corrosion Properties of Mg/SiO2 and MgO/SiO2 Multilayer Coatings for Magnesium Implant Devices
Authors: Kotoka R. , Fialkova S. , Neralla S. , Yarmolenko S. , Pai D. , Sankar J.
Published: March 2016

In this study, Mg/SiO2 and MgO/SiO2 multilayer coatings with bilayer thicknesses (Λ) 10, 20, 40, 100, 200 and 1000 nm were deposited on glass substrates using DC and reactive pulsed DC magnetron sputtering processes. The aim of these coatings is to control the initial degradation and provide mechanical strength to magnesium implant during handling and installation. The initial thickness calibrations and deposition rates optimization were conducted using stylus profilometer. After deposition of the multilayer coatings, the values of their bilayer thicknesses (Λ) were obtained from X-ray reflectometery. The mechanical properties, surface morphology and roughness of multilayer coatings were studied using nanoindentation, SEM and AFM respectively. The nanoindentation results showed higher hardness of MgO/SiO2 multilayer coatings compared to single layer Mg. The roughness analyses showed improved roughness for bilayer thicknesses (Λ) less than 20 nm. It was observed from the SEM images that SiO2 coatings has pores. By adding Mg and/or MgO in the form of multilayers improves the pores significantly. The Mg/SiO2 multilayer coatings showed controlled degradation rate when immersed in saline solution compared to the monolithic SiO2 coating. In conclusion, conditions for depositing Mg/SiO2 and MgO/SiO2 multilayer coatings has been optimized. Alternating brittle SiO2 ceramic layers with soft and ductile Mg layers significantly improved the hardness of the Mg coating. Hardness of multilayer coatings can be fine-tuned by modifying bilayer thicknesses. Significant improvement in the corrosion and mechanical properties of the multilayer coatings can be used to protect surface of magnesium implant material during handling, storage and installation.
Collapsible Wind Powered Energy Generation and Storage Device
Authors: Chambers Justin R. , Lowery Andrew D. , Smith James E.
Published: March 2016

The described research is a light weight, inexpensive portable and collapsible wind turbine, small enough to be carried in a backpack, ruck sack or within the storage compartment of a vehicle, which can be used to recharge batteries and provide off-site, emergency, or campsite power. As a means to extend the battery life of electronic equipment while moving away from the power grid and extra battery storage, a power generating unit is needed. Current approaches are to carry the anticipated number of spare batteries, to use solar cells or any number of small generating thermionic devices. While each of these have a place in the market, they also have negative cost, size, and weight drawbacks.

The objective of this research is to create a power generating/storage wind turbine device for recreational, emergency, and military use that can easily be collapsed and transported as needed. The device is a lightweight, collapsible wind turbine constructed of rugged materials to be used on camp sites, remote locations etc. and carried within a pack for travel. It is of a size and weight to be part of an emergency or survival pack. The wind turbine, in its preferred embodiment, is a self-starting/sustaining device that starts at low wind speeds so no monitoring or priming of the device is necessary. In addition to the novelty of it being collapsible, the wind turbine device employs advanced features to increase its wind energy capture efficiency and its energy storage and delivery system, along with unique design features that make it rugged, lightweight and easily assembled.
Variable Stiffness Mechanisms Using Spherical Continuously Variable Transmissions
Authors: Capehart Twan , Moore Carl A.
Published: March 2016

Some robot developers are considering elasticity to provide compliance for better adaption to a changing environment, shock resistance and safer human-robotic interactions (HRI). In this study we simulate a spherical continuously variable transmission (CVT) to validate its ability as the primary mechanism in a variable stiffness device for a 1D robotic hopper. The spherical CVT has been used in many robotic applications including cobots by Peshkin et al. [1] and as the driving unit in the load sensitive mechanism by Tadakuma et al. [2].

A CVT based variable stiffness/damping device intended for vibration mitigation was presented by Little [3]. That paper presented the kinematics and experiments of the CVT based variable stiffness/damping device for the specific application of vibration mitigation. This study considers the dynamics of the CVT based variable stiffness/damping device and modifies the device based on previous studies. We use ADAMS to simulate the modified system because it captures many of the real world dynamics arising from the CVT’s rolling friction dynamics. Finally we present a conceptual design of the variable stiffness CVT and briefly discuss its use in a 1D legged hopper application.
Evolution of Risk of Diesel Engine Emissions on Health During Last 4 Decades and Comparison With Other Engine Cycles: An Innovative Survey
Authors: Bari S. , Marian R.
Published: March 2016

Technological evolution has sometimes surprising and unintended consequences. Diesel engine improved drastically over time. Superficially, this translated into transforming dirty, smoky diesel engines into very clean units. However, the particles emitted by the latest engines are a several orders of magnitude smaller and more numerous. They are known as Ultra-fine particles (UFP). When they are formed in the combustion process, their surface adsorbs and traps harmful chemicals that may end up being delivered, aspired and harming humans, animals and plants. Over 40 mutagenic and carcinogenic chemicals are present in diesel exhaust particulates. Existing ceramic type filter for diesel engines, known as diesel particulate filter (DPF), is used to reduce both particulate matter (PM) number and mass concentration. The main disadvantages of DPF are cost, clogging of the filters and mechanical cracking during regeneration which causes them to fail. Alternative to DPF, devices made of metallic materials known as flow through filters (FTF) have become promising PM emission control devices. FTF have low pressure drop and less complex structure compared to DPF, but PM reduction efficiencies much lower than DPF. FTF with corona charging upstream of the filter to charge PM and imposing an electrostatic field onto the FTF to capture the PM is another alternative to DPF. This is known as electrostatic diesel particulate matter filtration system (EDPS). The EDPS has 40% more efficiency than FTF, but 10% less than DPF. This paper presents a thorough literature review on emissions, distribution of particles, their evolution and effects on health in the last 4 decades across spark ignited and compression ignited engines. The paper also discusses the characteristic and evolution of DPF, FTP and EDPS to capture diesel particles.
Experimental Investigation of Adding Vanes Into the Air Intake Runner of a Diesel Engine Run on Biodiesel to Improve the Air-Fuel Mixing
Authors: Bari S. , Saad Idris
Published: March 2016

Diesel engine can be run with renewable biodiesel which has the potential to supplement the receding supply of crude oil. Use of biodiesel in diesel engines can also reduce harmful emissions of CO, unburned HC and particulates. As biodiesel possess similar physiochemical properties to diesel, most diesel engines can be run with biodiesel with minimum modifications. However, the viscosity and calorific values of biodiesel are higher and lower, respectively than diesel which will affect the performance of diesel engine run with biodiesel. Use of 100% biodiesel in diesel engines shows inferior performance of having lower power and torque. Guide vanes into the intake runner to improve the in-cylinder airflow characteristic to break down higher viscous biodiesel is the aim of this research. This is expected to improve the air-fuel mixing resulting better combustion. The experimental results of biodiesel run in a diesel-gen set showed that break specific fuel consumption reduced in between 0.90 and 1.77% with vane numbers of 3 to 5. In regards to emissions, CO reduced in the range 0.05 and 8.78%, CO2 reduced in the range of 0.82 and 1.75%, and HC in the range of 1.19 and 7.49% with vane numbers of 3 to 5. Interestingly, most improvements were found with the vane numbers of 4.
Synthesis and Characterization of Conjugated-Polymer/Graphene/Nanodiamond Nanocomposite for Electrochemical Energy Storage
Authors: Illera Perozo Danny , Gómez Vega Humberto , Yepes Martínez Julian
Published: March 2016

The synthesis and characterization of Polyaniline/Graphene/ Nanodiamond Nanocomposite is reported. The resulting materials were synthetized following a polymerization in situ scheme and characterized by Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetry (TGA), Differential Scanning Calorimetry (DSC), Scanning Electron Microscopy (SEM) and Cyclic Voltammetry (CV). The effect of different loads of graphene and nanodiamond on the resulting nanocomposite was studied. Despite the presence of the host materials, the formation of Polyaniline polymer is successfully accomplished for all samples. The microstructure of the resulting materials is core-shell type with the additives being covered (core) by layers of the conjugated polymer (shell). The thermal stability of the nanocomposites is improved as confirmed by measuring an increase on the Temperature of Decomposition and the Cross-Linking Temperature compared to bare polymer. Electrochemical characterization reveals that the presence of the additives does not affect the electroactive behaviour of the matrix polymer allowing it to reversely shift from different oxidation stages. The effect of additive content on the charge transfer kinetics is discussed.
A Numerical Study of Multiphase Dielectric Fluid Immersion Cooling of Multichip Modules Including Effects of Nucleation Site Density and Bubble Departure Diameter Functions
Authors: Nguyen Jonathan , Knight Roy W. , Bhavnani Sushil H. , Harris Daniel K. , Fincher Seth , Gess Joshua , Sridhar Aravind
Published: March 2016

In this study, the computational fluid dynamics programs ANSYS Icepak along with ANSYS Fluent were used to model and simulate the multiphase dielectric fluid immersion cooling of a multichip model on a printed circuit board using a variety of functions for nucleation site density and bubble departure diameter. Numerical results were validated against experimental data for the same geometry and working fluid. The numerical model in this study is a reduced form of an experimental setup, which consisted of four equally spaced, 24 mm by 24 mm die, arranged in a square pattern and centered on a printed circuit board. The numerical model consisted of the die and printed circuit board vertically suspended in a large, quiescent 15°C subcooled pool of Novec 649. Heat was uniformly dissipated from the die at fluxes ranging from 3 to 12 W/cm2. Pool boiling curves were generated from the numerical results and compared with experimental data.

This study involved the comparison of several functions for two boiling parameters: nucleation site density and bubble departure diameter. Four combinations of the standard functions available in Fluent were simulated. Numerical results for the worst combination over predicted the wall superheat by an average of 35°C for heat fluxes ranging from 3 to 12 W/cm2. In addition, the vapor fraction was under predicted by an order of magnitude and the increasing slope of heat flux versus wall temperature seen in the nucleate boiling regime of typical boiling curves was not consistently reproduced. Parametric studies were performed in which six bubble departure diameter functions and twelve nucleation site density functions were simulated with the remaining boiling parameters set to default Fluent functions. Next, combinations of nucleation site density and user-defined bubble departure diameter functions were simulated together. The worst of these over predicted the wall superheat by an average of 3.4°C for heat fluxes in the range of 3 to 12 W/cm2. The best agreement was seen when experimental data for bubble departure diameter were implemented as a user-defined function along with user-defined nucleation site density; these simulations matched experimentally measured wall superheat within 1.3°C in the same heat flux range.