bluuebunny/crossref_metadata_2025 huggingface dataset:
Hysteresis Modeling and Parameter Identification of an Encapsulated Piezoelectric Actuator
Authors: Zhang Yang , Chen Zhaobo , Jiao Yinghou , Wei Yuan
Published: March 2016

The hysteresis of the piezoelectric actuator possesses the rate-dependent characteristics, which significantly affects the precision and response speed of the piezoelectric actuators. That challenges to the traditional modeling and control techniques in micro-/nano-manipulation. The static and dynamic experiments are performed to validate the rates-dependent characteristics of our proposed encapsulated piezoelectric actuator, including the preload-dependent, frequency-dependent and amplitude-dependent characteristics. In order to accurately predict the EPA output hysteresis displacement with respect to the driving voltage, the Bouc-Wen model is proposed. The corresponding parameter identification method is established to identify the parameters of the proposed Bouc-wen model. To evaluate the effectiveness of the proposed model and parameter identification method, the experimental system is implemented. The results indicate that the output displacement predicted by proposed Bouc-Wen mathematics model can match the measured data very well. The maximal absolute, relative and normalization total errors of the proposed Bouc-wen model are 0.548um, 4.26% and 0.0583 respectively, which shows the proposed Bouc-Wen model can well describe the hysteretic characteristics of the piezoelectric actuator.
Noise Source Identification and Experimental Research of Engine Compartment of a Forklift Based on Fast Independent Component Analysis and Scan and Paint
Authors: Zhang Enlai , Hou Liang , Yang Weiping
Published: March 2016

The noise signals from the engine compartment of a forklift are wideband non-stationary random signals as their structure and working process are complex. In order to separate and identify the noise sources of the engine compartment, blind source identification analysis was carried out based on fast independent component analysis (FastICA) algorithm and experimental research on noise sources localization were done by using Microflown’s Scan & Paint system. Firstly, a numerical analysis method for effectively achieving noise source identification was proposed. Secondly, the feasibility of FastICA algorithm and the efficiency of the proposed method were verified through simulation. Thirdly, the statistical independence and Gaussian of noise signals were analyzed. The results show that noise signals meet the preconditions of independent component analysis (ICA). Then, noise signals were separated by the proposed method. The corresponding relation between independent components (ICs) and different noise sources was obtained. And the accuracy of the identification results was validated with Scan & Paint sound source localization system. The differences between experimental and numerical analysis results are less than 5%. Finally, de-noising methods are devised based on sound source characteristics.
Steel Structure Prediction for Continuous Steel Casting by Means of a Parallel GPU-Based Heat Transfer and Solidification Model
Authors: Klimeš Lubomír , Štětina Josef , Mauder Tomáš
Published: March 2016

Continuous casting of steel is currently a predominant production method of steel, which is used for more than 95% of the total world steel production. An effort of steelmakers is to cast high-quality steel with a desired structure and with a minimum number of defects, which reduce the productivity. The paper presents our developed GPU-based heat transfer and solidification model for continuous casting, which is coupled with a submodel used for the prediction of the steel micro-structure. The model is implemented in CUDA/C++, which allows for rapid computing on NVIDIA GPUs. The time-dependent temperature distribution calculated by the thermal model is iteratively passed to the submodel for the steel micro-structure prediction. The structural submodel determines the spatially-dependent rates of temperature change in the strand, for which the interdendritic solidification model IDS predicts the micro-structure of steel. The paper presents preliminary simulation results for the steel grade used for pressure vessel plates, which is sensitive to rapid cooling rates.
Influence of Electric Fields and Surface Chemistry on Ice Nucleation Kinetics
Authors: Carpenter Katherine , Bahadur Vaibhav
Published: March 2016

The majority of studies on ice formation have attempted to prevent or reduce ice build-up; very few studies have focused on promoting ice nucleation which would have applications in appliances, cryopreservation, and pharmaceutical freeze-drying. Such studies are also relevant to the synthesis of methane hydrates for natural gas transportation. This paper details a fundamental study on the influence of interfacial electric fields on ice nucleation promotion.

Electrofreezing, i.e. applying an electric field has been shown to electrically induce nucleation of supercooled water. The freezing temperatures of supercooled water can thus be increased via electrofreezing. However, the mechanisms responsible for elevating the freezing temperature are unclear. Typically, bare electrodes are submerged in water, which creates a volumetric electric field in water. With this type of electric field, the application of a voltage can result in multiple phenomena such as current flows, chemical reactions and gas bubble formation or growth. It is unclear whether electrofreezing is the result of the electric field or the current flow-related secondary phenomena.

In the present work, the role of electric fields and surface charge on electrofreezing is isolated by studying electrofreezing of water droplets on a dielectric layer. This dielectric layer blocks current and creates an interfacial electric field with a build-up of electric charge at the solid-fluid interface. Ultra-high electric fields of up to 80 V/μm were applied, which is one order of magnitude higher than in previous studies. Infrared (IR) thermography was used to capture ice nucleation and determine the electrofreezing temperature. The results show that the electric fields alone can elevate the freezing temperature of water by as much as 15 °C; however, this effect saturates at electric fields of approximately 20–40 V/μm. Also, the electrofreezing effect was found to be polarity independent. Therefore, it is hypothesized that the mechanism underlying electrofreezing is a reduction in the Gibbs free energy for ice crystal nucleation. Furthermore, by intentionally creating pinholes in the dielectric layer, which creates current paths, the influence of electric current on electrofreezing was also studied. It was observed that electric currents and/or other secondary effects, such as bubble generation, further increased the electrofreezing temperatures.

Overall, this work fills many existing gaps in the current understanding of electrofreezing. It is seen that both the electric field and electric current influence electrofreezing; however, the physical mechanisms are different.
Coastal Hydrodynamic and Sediment-Salinity Transport Simulations for Southwest Louisiana Using Measured Vegetation Data
Authors: Han Xiao , Zhang Ning
Published: March 2016

Storm-surge flood is a major thread to the inhabitants and the health of the marshes in Southwest Louisiana. The floods caused direct damages to the area, but also indirectly caused excessive sedimentations in the water system, especially in Calcasieu Ship Channel which is a vital industrial water way connecting the City of Lake Charles to the Gulf. It is well known that coastal wetlands and marshes have significant impacts on the prevention and reduction of coastal floods. The wetland vegetation creates larger frictions to the flooding water and acts as the first line of defense against any storm surge floods. In this study, we center Calcasieu Ship Channel, and hydrodynamic and sediment transport simulations were conducted for Calcasieu Ship Channel and surrounding areas. The target area ranges from the city of Lake Charles as the north end and the Gulf of Mexico as the south end, and includes three connected water systems, Calcaiseu Lake, Prien Lake and Lake Charles. The entire Calcasieu Ship Channel running from north to south is included in the domain along with the Gulf Intracoastal Waterway (GIWW) in east and west directions. In authors’ previous study, only the area of south portion of the ship channel, Calcasieu Lake and its surrounding wetlands was simulated and studied. This study is a major upgrade to the model, which provides more complete understanding of the flow and sediment transport in the entire area, as well as the interactions among all water systems surrounding the ship channel. There are wetlands (two National Wild Life Refuges, one in the west and one in the east) surrounding Calcaiseu Lake, while there are various of vegetated and non-vegetated areas surrounding Prien Lake and Lake Charles. The standard 2-D depth averaged shallow water solver was utilized for the simulation of the flow phase and a standard Eulerian scalar transport equation was solved for the sediment and salinity phases. In the sediment phase, the sediment deposition and re-suspension effects are included, while in the salinity phase, the precipitation and evaporation are included. A realistic vegetation model was implemented to represent various types of vegetation coverage in the target area, and appropriate friction values were assigned to different non-vegetated areas. Measured and observed vegetation data were utilized. A coastal storm surge flood was simulated, and effects of vegetation on flood reduction and sediment distribution were investigated. The total flooded area, the flood speed, and the distribution of the flooding water and sediments were compared between vegetated and non-vegetated areas to show the differences between different types of surfaces.
Conceptual Design of an Active Transtibial Prosthesis Based on Expected Joint and Muscle Forces in a Unilateral Transtibial Amputee: A Modelling Study
Authors: Joshi Sagar , Gupta Abhishek
Published: March 2016

Most modern active prostheses try to match the torque generated by the biological ankle in order to assist walking. However, due to the absence of a biarticular component like the gastrocnemius muscle, they are unable to provide complete rehabilitation. In this paper, a conceptual design of a prosthesis, having an active biarticular component is proposed; and it is studied if such a design can help in better rehabilitation of amputees. The muscle and joint forces during walking are predicted for three cases using musculoskeletal models: A healthy person, an Amputee wearing an active uniarticular prosthesis, and an Amputee wearing a prosthesis having active uniarticular as well as biarticular components (proposed design).

Based on the required muscle forces and generated joint reaction loads, the proposed model performs better than the uniarticular prostheses.
Divergent Engineering
Authors: Fukuda Shuichi
Published: March 2016

This is a position paper.

Traditional engineering has focused on the design goal and all efforts have been paid to achieve design requirements and design specifications with the highest quality. Such engineering is indeed necessary to develop very high tech products or very sophisticated products.

But on the other hand, there are needs for engineering which makes the most of the available resources. To borrow Theodore Roosevelt’s words, “Do what you can, with what you have, where you are” is the philosophy of such an approach.

Current engineering is convergent engineering or tree-structured engineering. We invent or use many technologies to achieve our high goal. But if we look at the developing countries, local people are not capable of using such high sophisticated systems and what makes the matter worse, materials, etc. which are needed are not available locally. For them, what is more important is how they can utilize their own local materials or resources and develop a system which can be used and repaired by themselves.

Thus, not only physical resources, but such resources as human, etc. must be considered how to utilize them in order to cater to their local needs. And in fact, if we are successful in developing such local products by utilizing their own local resources, it would increase employment and the market will grow up. In short, low-end to high-end industrial development can be expected.

To achieve this, we need divergent engineering. An engineering to think how we can make the most of the resources at hand. The product thus developed may be low tech, but has quality and performance to satisfy the local needs enough.

And it should be added that such low tech products would serve to cater to quickly aging society as well. Products that call for high capabilities cannot be used by seniors. So unless products are for a professional user, even in advanced countries, most of which are suffering from the problem of quick aging populations, very high tech and sophisticated products will not meet the aging customers’ needs or expectations. We need much simpler and intuitive engineering.

Engineering is an activity to satisfy our dreams. But current convergent technology is too much stuck on the traditional path. Convergent engineering helps engineering going higher and higher, but it does not help it going wider and wider. It requires high expertise not only on the side of the producer, but also on the side of the customer.

To expand engineering wider and wider, we need divergent engineering. This paper discussed the importance of divergent engineering and describes its importance with illustrative examples.
Heat/Mass Transfer to a Drop Translating in a Perpendicular Electric Field
Authors: Abdelaal Mohamed R. , Huzayyin Omar A. , Jog Milind A.
Published: March 2016

Enhancement of heat or mass transport in a spherical drop of a dielectric fluid translating in another dielectric fluid in the presence of uniform electric field is investigated. The internal problem or the limit of the majority of the transport resistance being in the dispersed phase is considered. The transient energy conservation equation is solved using a fully implicit finite volume method.

In the literature, there is a plenty of studies that had been carried out when the electric field acts in the same plane of translation. In this paper, considering creeping flow regime, numerical computations have been conducted when the electric field acts perpendicular to the plane at which translation acts. As such the flow is no longer a two dimensional flow as a third component velocity comes to picture. At the first glance, thoughts of transport enhancement come to mind on the presence of a third velocity component that might promote mixing and consequently enhance transport effectiveness. Results are expressed in terms of the Nusselt number. Nusselt numbers are plotted in terms of Peclet number, Fourier number and the parameter L which is defined as the ratio of the maximum electric-field-induced surface velocity to translation-induced surface velocity. The code was validated by comparing, results for Peclet numbers of 500 and 1000 to corresponding cases available in literature. Results showed good agreement with previous results. A 3-D grid of 20×40×60 has been considered to cover the computational domain. A grid independence study has been carried out by doubling the whole grid. Results show acceptable results compromising accuracy and code running time. The effect of electric field is expressed in terms of parameter L.

For low Peclet numbers (Pe ≤ 250), the application of electric field perpendicular to the plane at which translation acts leads to enhancement of heat/mass transport compared to that in pure translation. Such enhancement is about the same when the electric field and translation act in the same plane. On the other hand, for moderate Peclet numbers (Pe= 250∼1000), the transport enhancement is significant when compared to the enhancement obtained by an electric field acts in the same plane of action of translation as well as pure translation. These results can be understood by comparing time scales for diffusion and convection. When Peclet number is low the convection time scale is very large and hence mixing is not that effective in promoting heat / mass transfer. Whereas for moderate Peclet number, when the convection time scale gets smaller, heat/mass transfer is considerably enhanced compared to low Peclet numbers.
A Preliminary Study on Small Thermoplastic Composite Wind Turbine Blade Design and Fabrication
Authors: Garate Juan , Solovitz Stephen A. , Kim Dave
Published: March 2016

Today a large-scale wind turbine blade can be 70 m long and 5 m in root chord length, and it is fabricated in a single piece. This feature leads to high initial costs, as transportation of a large blade requires special trucks, escorts, and road adaptations. These constraints can account for approximately 6–7% of the total investment for the blade. In addition, the manufacturing process commonly used is a hand lay-up configuration of thermoset composite sheets. These materials are not reusable after fabrication, which is a non-renewable feature of existing systems. The project consists of manufacturing thermoplastic composite blades in segments, which are joined before installation at the turbine site. This paper addresses the preliminary research results when conducting design and fabrication of a small blade with this innovative approach. Three segmented blades are manufactured for a horizontal-axis wind turbine, with each blade having a 50 cm span and a 4 cm tip chord length. The blade size and profile are designed based on the idealized Betz limit condition. The material used for manufacturing is a glass fiber reinforced thermoplastic composite system with a polypropylene matrix that melts at 200 °C. Each blade is fabricated in 4 independently manufactured pieces, consisting of top/bottom, and tip/root segments, via a vacuum assisted thermoforming technique. The parts will be assembled afterwards by a joining process, forming the final part for site testing.
Corrosion Behavior of Tricalcium Phosphate Doped With Different Compositions of Silver
Authors: Yamoah Nana Kwame , Moses Timothy , Kumar Dhananjay
Published: March 2016

In this study, magnesium (Mg) disks were coated with β-tricalcium phosphate (β-TCP) doped with different mass percent of silver (Ag) (0 wt%, 1 wt%, 5 wt% and 10 wt%) in an effort to modulate the detrimental osteoimmunomodulatory properties and colonization of bacteria on Mg disk, due to the reported favorable osteoimmunomodulatory properties of β-TCP and antibacterial properties of Ag. This paper describes the growth, characterization and corrosion analyses of β-TCP doped with different compositions of Ag thin film coatings. The phase composition and microstructure analyses were performed using X-ray diffraction (XRD) and scanning electron microscopy (SEM) respectively. The SEM images showed that varying the percentage of Ag dopant affects the surface morphology of the β-TCP coatings. The corrosion protection behavior of the coated samples were evaluated using electrochemical measurement techniques, such as potentiodynamic polarization (PD) and electrochemical impedance spectroscopy (EIS). The corrosion tests were performed in Hank’s Balanced salt solution using a three-electrode electrochemical cell. The results showed that the β-TCP coating and β-TCP doped with Ag coatings on the Mg disks exhibit a much superior stability and lower corrosion rate compared to bare Mg. It was observed that increasing the mass of the Ag dopant increases the corrosion protection, but 10 wt% Ag doping in β-TCP reduces the corrosion protection behavior. The SEM images of the samples after corrosion show that the β-TCP and β-TCP doped with 10 wt% Ag suffered the most corrosion attack compare to β-TCP doped with 1 wt% and 5 wt% Ag. In conclusion, we have developed β-TCP and β-TCP doped with 1 wt%, 5 wt% and 10 wt% Ag coating with tunable corrosion protection efficiency above 88%.
Vortex Shedding Control Using a Permeable Plate Located Around the Separation Point of a Circular Cylinder
Authors: Ozkan Gokturk Memduh , Akilli Huseyin
Published: March 2016

The flow downstream of a plain cylinder with attached permeable plates having various porosity ratios was investigated experimentally using both Particle Image Velocimetry (PIV) and dye visualization techniques to control the vortex shedding around the circular cylinder. The diameter of the cylinder and length to diameter ratio of the plate were kept constant as d= 50 mm and L/d=1.0, respectively. The porosity ratio, β which can be defined as the ratio of open area to the whole body surface area was taken as β=0.4, 0.5, 0.6, 0.7 and 0.8 (permeable plates). The study was performed considering deep water flow conditions and depth-averaged free stream velocity was taken constant as U = 95.2mm/s which corresponded to a Reynolds number of Red = 5000 based on the cylinder diameter. The results of a plain cylinder were compared with the results of cylinder with permeable plates in order to understand the control effect. Both qualitative and quantitative results revealed that the plates are effective on the unsteady flow structure downstream of the cylinder, i.e. the vortex formation length was increased, turbulent statistics was reduced and both width and length of the wake were changed by usage of permeable plates attached around the separation point of the cylinder.
Effect of the Patch Material and Dimension on the Vascular Mechanics After Aortic Coarctation Repair Surgery
Authors: Li Zhuoran , Zhao Shijia , Abdullah Ibrahim , Kutty Shelby , Gu Linxia
Published: March 2016

The patch material and dimension are two important factors which might affect the surgical outcomes after the aortic arch coarctation repair surgery. To quantity their acute impacts on the biomechanical environment of the repaired aortic arch, an aortic arch model was constructed and the fluid-structure interaction (FSI) technique was utilized to characterize its hemodynamics and wall mechanics. Three different patch materials were considered including pulmonary artery, ECM CorMatrix and Polytetrafluoroethylene (PTFE). The induced wall shear stress, distribution of flow patterns, and von-Mises stress on arterial wall were compared. Results showed that ECM CorMatrix patch had better performance Two different patch dimension (large v.s small) using CorMatrix patch were compared and the relatively smaller patch demonstrated a better hemodynamics than the larger one. No significant difference in terms of wall stress was observed between the different patch sizes.
Gas Separation by Using Spiral Wound Membrane
Authors: Alrehili Mohammed , Usta Mustafa , Alkhamis Nawaf , Anqi Ali , Oztekin Alparslan
Published: March 2016

Spiral wound membrane is used in several industrial purification processes such as desalination, food industries and gas separation. It has been shown that membrane performance could be greatly enhanced by momentum mixing in the feed channel induced by spacers. Square shaped spacers will be considered in inline geometries for the Reynolds number, Re, of 300 and 500. A separation of CO2 from CH4 will be investigated. A computational fluid dynamics simulation will be conducted for flows of a binary mixture of CO2 and CH4. The mass flux through the membrane will be determined based on the local partial pressures of each species, the permeability, and the selectivity of the membrane. Shear Stress Transport turbulence model will be employed to capture the steady state velocity and concentration field. The transient effect on the momentum mixing will be studied using lattice Boltzmann method. Two dimensional nine velocity directional, D2Q9, lattice arrangement with multi-relaxation time (MRT) lattice Boltzmann method is used to simulate transient flow field while single relaxation time (SRT) lattice Boltzmann method is employed to simulate concentration field for Re = 100 and 300. The bounding surfaces are treated as impermeable walls for simulations conducted using the lattice Boltzmann method. The results predicted by lattice Boltzmann and SST turbulence model agree well.
Effect of Heat Exchanger Orientations to Recover Heat From the Exhaust of a Diesel Generator Using Rankine Cycle (RC)
Authors: Bari S. , Hossain Shekh N.
Published: March 2016

The heat from the exhaust gas of diesel engines can be an important heat source to provide additional power and improve overall engine efficiency. Studies related to the applications of recoverable heat to produce additional power using separate Rankine cycle are scare. To recover heat from the exhaust of an engine, an efficient heat exchanger is necessary. For this type of application, the heat exchangers are needed to be designed in such a way that it can handle the heat load with reasonable size, weight and pressure drop. In this project, experiments were conducted to measure the exhaust heat available from a 40 kW diesel generator at different loads. Shell and tube heat exchangers were purchased and installed into the engine. The performance of the heat exchangers using water as the working fluid was then conducted. With the available data, computer simulation was carried out using CFD software CFX to improve the design of the heat exchangers. Geometric variables including length, number and diameter of tubes, and baffle design were all tested separately. Upon investigating how these parameters influenced the heat exchangers’ effectiveness, optimum design of shell and tube heat exchangers was proposed. The proposed heat exchangers were manufactured and experiment was conducted. Two heat exchangers were used to generate superheated steam. These two heat exchangers were arranged in two orientations namely, series and parallel. The proposed heat exchanger was able to produce 2.71 kW additional power using water as the working fluid at an optimum working pressure of 15 bar using parallel arrangement. It was found that parallel arrangement generated 10% more additional power than the series arrangement.
Novel Application-Specific Methodology for the Assessment of Microfin Tube Condensation Heat Transfer Correlations
Authors: Kale Kaustubh S. , Mehendale Sunil S.
Published: March 2016

Extensive critical study of five popular microfin tube correlations for condensation heat transfer coefficients (HTCs) was carried out. The principal aim of this investigation was to develop an application-specific quantitative tool to assess the predictive accuracy and applicability of these correlations for halogenated refrigerants as well as CO2. This novel methodology was developed and validated against a dataset of 1163 experimental data points for CO2, R22, R134a, R410A, R407C, R125 and other halogenated refrigerants obtained from a large number of published works which included diverse microfin tube geometries and condensing conditions. The tool will enable the engineer or experimentalist to select the best (i.e., most accurate) condensation HTC correlation for a given microfin tube application, thereby significantly reducing tube testing costs, leading to lower turn-around times and more efficient designs. Based on the analysis carried out using the new methodology, it was found that overall, Cavallini et al. (2009) was the most widely applicable and accurate flow condensation correlation. Yu and Koyama (1998) was found to perform well for CO2, 7 mm and smaller tubes and low helix angles (5° to 10°). Interestingly, Cavallini et al. (2009), Yu and Koyama (1998) and Chamra et al. (2005) were found to predict the HTC satisfactorily for zeotropic refrigerants such as R407C, although their development was based on pure and near-azeotropic refrigerants only. The Han and Lee (2005) correlation was found to be inaccurate over most of the data set and therefore has a very low probability of being recommended for any application.
Characterization of Material Properties for Multi-Scale Polymer Composites Extruded From Straight and Divergent Die Geometries Using Various Filler Concentrations
Authors: Nixon Jason R. , Lempert Inna , Choi Hyunjo , McFarlane Jeremy , Bigio David I.
Published: March 2016

The addition of nano-scale and micro-scale fillers has been proven to increase tensile and thermal properties in polymer composites. Orientation of high aspect fillers, however, has not been studied before despite being crucial to altering physical properties. When fibers are included during extrusion, they tend to align in the direction of the flow. This phenomena leads to longitudinal improvements in mechanical properties, and thus provides great benefits in some applications; however, it is beneficial to have improved properties in the transverse direction as well. Therefore, it is crucial to study reorientation phenomena in composites.

The purpose of this experiment is to study property enhancement resulting from fiber structure. The material properties are compared for the range of weight percentages of fillers. This is done for the purpose of finding an ideal fill concentration. Two dies are used to study different orientation distributions: straight and divergent. Thermal and tensile properties and optical micrographs are analyzed and compared.

Composites were processed on a Coperion ZDSK-28mm co-rotating, fully-intermeshing, twin-screw extruder. Polybutylene terephthalate (PBT) was used as the polymer matrix. 0 W% to 2 W% multi-walled carbon nanotubes (CNTs) and 0 W% to 30 W% carbon microfibers (CMFs) were used as fillers.

Preliminary results showed a clear trend in increased tensile strength of the composite with the increase of concentration of CMFs and CNTs in the slit die up to 25 W% CMF. After 25 W% CMF, however, there was a depreciation in properties. Similarly, thermal conductivity results have shown a clear peak at 25 W% CMF with 30 W% showing a decrease in thermal properties.

Preliminary results for the divergent die showed that, with addition of carbon microfibers to the polymer matrix, thermal properties of the composite increased up to 15 W%, then dropped and increased again as more CMFs were added. In addition, on average, material extruded through the divergent die showed better results of thermal conductivity than that extruded through the slit die. This indicates that when using a diverging die, fiber become oriented perpendicular in relation to the direction of the flow, thus improving heat flow in the transverse direction.
Synthesis and Characterization of Hydroxyapatite Using Egg-Shell
Authors: Rasool Tabinda , Ahmed Syed Rehan , Ather Iqra , Sadia Madeeha , Khan Rashid , Jafri Ali Raza
Published: March 2016

Advancement in materials science and manufacturing processes helps in expanding the application span of materials in biotechnology. The technological development of biocompatible materials aids in improving health conditions, cancerous treatment, organ implants, and as well as provides several techniques to patient treatment. Hydroxyapatite (HAP) is considered as a potential material for orthopedics and dental implants due to its eminent biocompatibility and natural apatite characteristics. It is regarded as viable and cost effective solution of many biomedical applications. Major challenges in expanding the application span of HAP include obtaining optimum mechanical, chemical, and biological properties simultaneously while making its manufacturing processes cost effective. The main purpose of the current work is to synthesize and characterize high strength HAP with high degree of crystallinity and purity, which could be able to fulfill the requirements of modern biological materials. In this work, egg-shell which is considered as garbage is utilized as calcium source to synthesize HAP. Initially, egg-shells are properly cleaned with distilled water and dried. Ball milling operation is used to produce egg-shell particles of nano to micron range. The particles then mixed with controlled amount of phosphoric acid. The mixture is then sintered by heat treating at 900°C for 2 hours. The heat treatment (sintering) process is used to enhance the density as well as strength of egg-shell material. After synthesis of HAP, it is characterized through X-ray diffraction, scanning electron microscopy, and laser particle analyzer. Composition of HAP is investigated through XRD. Furthermore, surface topography of nano-crystalline HAP powder is measured through Scanning Electron Microscope while particle size distribution is found through laser particle analyzer. It is found that the addition of phosphoric acid in milled egg-shell and heat treatment give rise HAP in the sample. In addition, particle size varies from hundreds of nanometers to several micrometers. The results and analysis of the current work may provide insight of different properties which may lead to the development of optimum and cost effective HAP material. The current study could be further extended in increasing application envelop of biocompatible materials.
Centrifugal Power Transmission Apparatus Design, Development, and Optimization
Authors: Ardis Abel , Asiabanpour Bahram , Hawkes Nicholas , Khodabakhsh Mohammed , Mathis Steven
Published: March 2016

This research focuses on the design optimization of the mechanical and electrical mechanisms, structure, and materials of an innovative apparatus capable centrifugal power-based of transferring power with a near-zero energy loss. In addition to mechanical and electrical system development, this study optimizes the product and improves the efficiency of the system so that it is lighter, costs less, wastes less energy, is easier to manufacture and assemble in low quantity and mass produce. The mechanism has many potential uses in lifting systems, drilling, and windmill mechanisms.
Predictive Cardiovascular Model With Blood Flow Measurements
Authors: Jo-Avila Miguel , Al-Jumaily Ahmed , Lu Jun
Published: March 2016

Cardiovascular disease is one of the leading causes of death in the world, accounting for 30% of all deaths worldwide and 40% of those occurring in New Zealand. In recent years, engineers and scientists have collaborated with the medical community to find new methodologies and approaches for assessing, investigating and understanding the development of cardiovascular diseases. Elements such as computational models developed with fluid dynamic elements (CFD/FE) have become excellent tools for this purpose. One of the important approaches is developing devices for investigating the central blood flow and pressure, and correlating the results to different heart diseases. Higher-valued changes in central blood flow and pressure mean that the heart must work harder. A computational model capable of predicting inlet and outlet locations of a blockage would be helpful to determine different stages of cardiovascular disease. By using reflection signals from the central blood flow that are detected at locations such as the brachial artery or subclavian artery, it is possible to model the effect of flow and pressure differences on heart diseases.
Static Response of Microbeams due to Capillary and Electrostatic Forces
Authors: Bataineh Ahmad M. , Ouakad Hassen M. , Younis Mohammad I.
Published: March 2016

Micro-sensors or micro-switches usually operate under the effect of electrostatic force and could face some environmental effects like humidity, which may lead to condensation underneath the beams and create strong capillary forces. Those tiny structures are principally made of microbeams that can undergo instabilities under the effect of those created huge capillary forces. In fact, during the fabrication of microbeams, there is an important step to separate the beam from its substrate (wet etching). After this step, the microstructure is dried, which may causes the onset of some droplets of water trapped underneath the beam that could bring about a huge capillary force pulling it toward its substrate. If this force is bigger than the microbeam’s restoring force, it will become stuck to the substrate.

This paper investigates the instability scenarios of both clamped-clamped (straight and curved) and cantilever (straight and curled) microbeams under the effect of capillary and/or electrostatic forces. The reduced order modeling (ROM) based on the Galerkin procedure is used to solve the nonlinear beam equations. The non-ideal boundaries are modeled by adding springs. The volume of the fluid between the beam and the substrate underneath it is varied and the relation between the volume of the water and the stability of the beam is shown. An analysis for the factors of which should be taken in to consideration in the fabrication processes to overcome the instability due to huge capillary forces is done. Also the size of the electrode for the electrostatic force is varied to show the effect on the micro-switch stability. A variation of the pull-in voltage with some specific beam parameters and with more than one case of electrode size is shown. It is found that capillary forces have a pronounced effect on the stability of microbeams. It is also found that the pull-in length decreases as the electrode size increases. It is also shown that the pull-in voltage decreases as the amount of fluid underneath the beam increases.
Thermal Property Measurement of Thin Fibers: A Direct Approach
Authors: Munro Troy , Xing Changhu , Ban Heng , Copeland Cameron , Lewis Randolph , Glorieux Christ
Published: March 2016

Fiber thermal characterization is often accomplished by indirect means, such as embedding the fiber in a matrix, measuring the thermal response of the composite, and relating for the contributions of the fiber and matrix to the overall behavior or measuring bundles of fibers. To improve the accuracy of the composite-based or bundle-based techniques, several different contact (hot wire and dc thermal bridge) and non-contact (Raman shift and IR thermography) methods have been developed to directly measure the thermal properties of individual fibers. To improve on the shortcomings of these methods, this paper presents the experimental results of an improved transient electrothermal (TET) method, as well as a 3ω-based method that better accounts for all sources of heat transfer, particularly heat loss by radiation. The incorporation of radial radiation heat loss becomes a significant factor as the size of the fibers decrease. This work describes practical applications of the methods to measure the properties of the fibers, including sample preparation for electrically conductive and non-conductive samples, data acquisition and calibration, data analysis, and sample property determination.

Results include validation of the methods with electrically conductive (platinum) and non-conductive (glass) fibers to improve upon the initial validation of the generalized electrothermal method which focused only on short, conductive fibers. The axial thermal conductivity and diffusivity of several high performance fibers are presented. The novelty of this paper is that it serves as both a compilation of previous research on the transient electrothermal and 3ω methods [1–6], measurements of new silk fibers, and practical information associated with the methods that improve the accuracy of the measured thermal property, as well as presenting thermal properties of additional fibers (carbon fiber and natural and synthetic spider silks).

To improve upon the long sample preparation time required for the TET and 3ω methods, future work focused on the development of a quantum dot-based photothermal fluorescence method is presented.
Numerical Investigation of Actuator Disc Thickness Effect on Predicting the Performance and Far Wake of the Horizontal Axis Wind Turbine
Authors: Behrouzifar Ali , Darbandi Masoud , Schneider Gerry E.
Published: March 2016

In this paper, the actuator disk (AD) method is used to simulate the wind turbine performance and far-wake behavior. In this work, we incorporate the AD method with an axisymmetric full Navier-Stokes solver. In other words, the calculated AD load is suitably distributed on the disc to impose the aerodynamic forces acting on the blade. One important factor among various different factors, which affect the AD modeling prediction considerably, is the utilized grid thickness. In this work, we first choose the grid thickness recommended by the other researches and study the actual thickness of NREL 5MW wind turbine. Next, many other configurations are considered in our AD thickness modeling including a constant thickness and the actual thickness configurations. The latter one has a linear thickness distribution from 3.54 m at the root to 0.7 m at tip. The wind speed is ranged from 3 to 11 m/s consistent with the practical tests performed on the NREL 5MW wind turbine. We calculate the generated power for all the simulated configurations and their percentages of differences. The results show that the lowest difference is about 4.5% for a constant AD thickness of 0.2 m. Therefore, we conclude that the current AD model predicts results very close to the NREL design data. Additionally, this accurate prediction is similarly observed in the other ranges of wind turbine operational speeds.
Semantic Alignment for Interoperable Manufacturing Networks Establishment
Authors: Branco Fabio , Marcelino-Jesus Elsa , Sarraipa Joao , Ilie-Zudor Elisabeth , Jardim-Goncalves Ricardo
Published: March 2016

Nowadays, SMEs aim to establish business’s networks to be competitive with multinationals, which requires the sharing of knowledge, strategies and resources to boost the sector’s and the cooperation’s consolidation. Even if all the enterprises of a business network alliance come from the same business area, each one has its own view or perspective of its domain knowledge. Thus different conceptual, semantic and lexical knowledge representations may occur and therefore it is expected to happen non-transparent and interoperability inconsistencies of the shared information. This paper proposes a web user interface component that could enable to identify and classify the resulting possible semantic heterogeneities in a flexible way. This software component will then support the semantic mapping establishments that answer the mentioned requirements.
An Examination of Isolated and Interaction-Based Biomechanical Metrics for Potential Lower Neck Injury Criteria
Authors: Chirvi Sajal , Pintar Frank A. , Yoganandan Narayan
Published: March 2016

Lower neck injuries inferior to C4 level, such as fractures and dislocations, occur in motor vehicle crashes, sports, and military events. The recently developed interaction criterion, termed Nij, has been used in automotive safety standards and is applicable to the upper neck. Such criterion does not exist for the lower neck. This study was designed to conduct an analysis of data of lower neck injury metrics toward the development of a mechanistically appropriate injury criterion. Axial loads were applied to the crown of the head of post mortem human subject (PMHS) head-neck complexes at different loading rates. The generalized force histories at the inferior end of the head-neck complex were recorded using a load cell and were transformed to the cervical-thoracic joint. Peak force and peak moment (flexion or extension) were quantified for each test from corresponding time histories. Initially, a survival analysis approach was used to derive injury probability curves based on peak force and peak moment alone. Both force and moment were considered as primary variables and age a covariate in the survival analysis. Age was found to be a significant (p<0.05) covariate for the compressive force and flexion moment but insignificant for extension moment (p>0.05). A lower neck Nij formulation was done to derive a combined interactive metric. To derive cadaver-based metrics, critical intercepts were obtained from the 90% injury probability point on peak force and peak moment curves. The PMHS-based critical intercepts derived from this study for compressive force, flexion, and extension moment were 4471 N, 218 Nm, and 120 Nm respectively. The lower cervical spine injury criterion, Lower Nij (LNij), was evaluated in two different formulations: peak LNij and mechanistic peak LNij. Peak LNij was obtained from the LNij time history regardless of when it occurred. Mechanistic peak LNij was obtained from the LNij time history only during the time when the resulting injury mechanism occurred. Injury mechanism categorization included compression-flexion, compression-extension, and those best represented by a more pure compression-related classification. Mechanistic peak LNij was identified based on the peak timing of the injury mechanism. Peak LNij and mechanistic peak LNij were found to be significant (p<0.05) predictors of injury with age as a covariate. The 50% injury probability was 1.38 and 1.13 for peak LNij and mechanistic peak LNij, respectively. These results provide preliminary data based on PMHS tests for establishing lower neck injury criteria that may be used in automotive applications, sports and military research to advance safety systems.
Quantifying the Thermal Accommodation Coefficient for Iron Surfaces Using Molecular Dynamics Simulations
Authors: Sipkens T. A. , Daun K. J. , Titantah J. T. , Karttunen M.
Published: March 2016

With nanotechnology becoming an increasingly important field in contemporary science, there is a growing demand for a better understanding of energy exchange on the nanoscale. Techniques, such as time-resolved laser-induced incandescence, for example, require accurate models of gas-surface interaction to correctly predict nanoparticle characteristics. The present work uses molecular dynamics to define the thermal accommodation coefficient of various gases on iron surfaces. A more in depth analysis examines the scattering distributions from the surfaces and examines how well existing scattering kernels and classical theories can represent these distributions. The molecular dynamics-derived values are also compared to recent experimental time-resolved laser-induced incandescence studies aimed at evaluating the thermal accommodation coefficient across a range of surface-gas combinations.
Modeling, Simulation and Experimental Validation of Heat Transfer During Selective Laser Melting
Authors: Masoomi Mohammad , Gao Xiang , Thompson Scott M. , Shamsaei Nima , Bian Linkan , Elwany Alaa
Published: March 2016

Selective Laser Melting (SLM), a laser powder-bed fusion (PBF-L) additive manufacturing method, utilizes a laser to selectively fuse adjacent metal powders. The powders are aligned in a bed that moves vertically to allow for layer-by-layer part construction-Process-related heat transfer and thermal gradients have a strong influence on the microstructural features, and subsequent mechanical properties, of the parts fabricated via SLM. In order to understand and control the heat transfer inherent to SLM, and to ensure high quality parts with targeted microstructures and mechanical properties, comprehensive knowledge of the related energy and mass transport during manufacturing is required. In this study, the transient temperature distribution within and around parts being fabricated via SLM is numerically simulated and the results are provided to aid in quantify the SLM heat transfer. In order to verify simulation output, and to estimate actual thermal gradients and heat transfer, experiments were separately conducted within a SLM machine using a substrate with embedded thermocouples. The experiments focused on characterizing heat fluxes during initial deposition on an initially-cold substrate and during the fabrication of a thin-walled structure built via stainless steel 17-4 powders. Results indicate that it is important to model heat transfer thorough powder bed as well as substrate.