bluuebunny/crossref_metadata_2025 huggingface dataset:
Thermal Performance of Earth-Air Heat Exchanger Systems for Cooling Applications in Residential Buildings
Authors: Ghaith Fadi A. , Ur Razzaq Habib
Published: January 2019

This paper addresses the thermal performance of integrating Earth Air Heat Exchanger (EAHE) systems with the conventional air conditioning systems in residential buildings in UAE. The proposed system was designed and simulated using a transient analysis tool TRNSYS. The system components were optimized by evaluating the effect of varying several design parameters on the performance of the system. It was found that the optimized design of the earth tubes could potentially reduce the temperature of the ambient air from 46 °C to around 29 °C, when the earth tubes were buried at 4 meters depth below the ground surface. This pre-cooled fresh (atmospheric) air from earth tubes was then mixed with the return air in the mixing chamber of conventional air cooling systems before supply to the building. In order to assess the system feasibility, the proposed system was modelled and implemented on a realistic case study represented by a four-floor residential building located in Dubai. This building comprised a total roof area of 400 m2 and an annual cooling load requirement of 366 kW. The results showed good potential of savings in terms of lowering the Annual Energy Consumption (AEC) and the consequent reduction in CO2 emissions.
Assessment of Induced Delamination During End-Milling of Natural Fiber Reinforced Composites: A Statistical Analysis
Authors: Alzebdeh Khalid I. , Nassar Mahmoud M. A. , Al-Hinai Nasr
Published: January 2019

The use of natural fiber reinforced composites has emerged as an advantageous option in many industrial applications. Generally, composites are manufactured in net or near-net shape, but under specific design specifications, secondary manufacturing processes such as drilling, milling and turning become a requirement. In this context, current paper presents an experimental study that investigates the machinability of newly developed natural fiber composites under conventional end-milling. Two types of bio-composites; date palm fronds reinforced polypropylene (DPF/PP) and pine needles reinforced polypropylene composite (PN/PP) were developed and physically tested in order to optimize their mechanical strength. Then, machinability of such class of bio-composites is statistically analyzed using Design of Experiment method. Statistical modeling including response surface plots are utilized to analyze the combined effect of input processing parameters (feed rate, axial depth, spindle speed) on the induced delamination during end-milling. It is shown that feed rate is the most dominant factors in DPF/PP milling, and axial depth of cut is the most significant factor on PN/PP milling. Results are also compared with those of milled neat polypropylene, which confirm that delamination of machined bio-composites can be improved over the neat polypropylene matrix. This qualifies the developed bio-composites to be used in industrial applications in which machining is required.
Thermal Design and Performance Prediction of a Shell Condenser for Closed-Cycle Underwater Vehicles
Authors: Chen Peiyu , Yan Hongbin , Xie Gongnan , Sunden Bengt
Published: January 2019

The shell condenser is a key component for the underwater vehicles. To study its heat transfer performance and flow characteristics and to design a more efficient structure, a mathematical model is generated to simulate condensation inside the straight and helical channels. The model combines empirical correlations and MATLAB based on an iterative algorithm. Here, quality is used as a sign of the degree of condensation. The computational model is verified by comparison of simulations and experiments. Several cases are designed to reveal the effects of the initial condition. The inlet temperature varies from 160 to 220°C and the inlet mass velocity ranges between 133 and 200 kg/m2·s. The results show that the inlet temperature and mass velocity significantly affect flow and heat transfer in the condensation process. In addition, comparisons of the straight channel and helical channel with different Dh/R indicate that the heat transfer capability of the helical channel is obviously better than that of the straight channel, and the heat transfer coefficient and total pressure drop increase with the decrease of Dh/R. This study may provide useful information for performance prediction and structure design of shell condensers, and provide a relatively universal computational model for condensation in channels.
Estimation of Energy Conservation in Internal Combustion Engine Vehicles Using Ionic Liquid As an Additive
Authors: Magar Sameer , Guo Hong , Iglesias Patricia
Published: January 2019

Lubricants play a vital role in improving energy efficiency and reducing friction in any type of frictional contact. The automotive industry is facing strict regulations in terms of emissions from the petroleum fuel. Strict government norms are compelling automotive manufacturers to push their technological limits to improve the fuel economy and emissions from their vehicles. Improving the efficiency of the engine will ultimately result in saving fuel thus improving the fuel economy of the engine. Concerning energy consumption; 33% of the fuel energy developed by combustion of fuel is dissipated to overcome the friction losses in the vehicle [1]. Out of this, 11.56% of the total fuel energy is lost in engine system. The distribution of this 11.56% fuel energy lost in engine system includes 3.5% consumed in bearings, 1.16% in pumping and hydraulic viscous losses, 5.2% and 1.73% consumed in piston assembly and valve train respectively [1]. If we consider losses only in bearings, piston assembly and valve train it results in 10.4% energy loss as compared to the total energy generated by the fuel. In the last decade, ionic liquids have shown potential as lubricants and lubricant additives. This study focusses on the use ionic liquids as additives for friction and wear reduction resulting in energy conservation in an internal combustion engine. In this work, the contact between piston ring and cylinder wall was simulated using a ball-on-flat tribometer. Most of the engine oils are based on mineral oils and results showed that adding 1% of the ionic liquid to mineral oil reduced friction loses by 27% [2], which corresponds to conserving 2.8% of fuel energy if just the frictional loss in piston assembly, valve train and bearing are considered. In the United States, there are 253 million vehicles on average consuming 678 gallons of fuel per year [3], the use of ionic liquid can save an estimated 4.8 billion gallons of fuel per year, which results in estimated saving of 11.56 billion dollars.
Demonstrating the Potential of a Hybrid Model to Increase the 360 Degrees Rotational Motion Freedom of Ironless Permanent Magnet Planar Motors
Authors: Yuan Ding , Zhang Ming , Zhu Yu , Li Xin , Wang Leijie
Published: January 2019

The ironless permanent magnet planar motors (IPMPMs) are used in the lithography machine to realize long stroke x, y translation with single mover. The lack of rotation motion limits its use in a wide range of applications. This paper proposes a hybrid model for the IPMPM to realize the rotational motion. Based on the decoupling feature, the influence cause by the x, y translation and the rotation can be expressed by the position functions and 1-d lookup table (LUT) respectively. To the coils with centro-symmetry, the hybrid model can be further simplified. Then simulations about the calculation speed and the model accuracy are conducted. Compared with the 3-d LUT, the hybrid model cost less time with relative high accuracy. Finally the validity of the hybrid model is verified by experiment.
Effect of Different Cutting Depths to the Cutting Forces and Machining Quality of CFRP Parts in Orthogonal Cutting: A Numerical and Experimental Comparison
Authors: Miah Farid , De-Luycker Emmanuel , Lachaud Frederic , Landon Yann , Piquet Robert
Published: January 2019

The necessity of understanding the influence of cutting variables in orthogonal cutting of Carbon Fiber Reinforced Polymer (CFRP) is vital because of their significant influences to the quality of manufactured parts. In this present research work the influences of different cutting depths to the cutting and thrust forces have been analyzed and a comparison between an equivalent homogeneous material (EHM) macro-model and experimental results have been made. The reasons of the beginning high cutting and thrust forces have been studied and explained. The post analysis of the experimental machined surfaces has been done to analyze the generated surface roughness and fiber-matrix interface crack generation. Five different cutting depths and four individual fiber orientations have been tested both numerically and experimentally. Significant influence of cutting depths to the cutting force has been found and the surface quality of newly generated machined part is discovered as a function of cutting depth and fiber orientation.
Objective Evaluation of FCV Interior Sound Quality During Acceleration
Authors: Liu Hai , Zhang Yanyi , Hao Dong , Chen Yong , Ji Xiang , Wei Changyin
Published: January 2019

While driving a FCV during acceleration, many sorts of sounds could be heard, which influence the interior sound quality. A typical FCV is taken as a sample, four interior noises generated under the acceleration operation are collected in the whole vehicle semi-anechoic chamber, and the noise sample database of diesel engine radiation noise is established after preprocessing. Based on sound quality theory (physical and psychoacoustic features), the Kernel Principal Component Analysis (KPCA) is used to extract the key objective features mainly influencing the sound quality, which realize the dimension reduction target; the variations of objective features are analyzed to qualitatively analyze the law of the sound quality varying during acceleration. According to the objective evaluation of FCV interior sound quality, combining with FCV operating parameters, the influencing law of the FCV sound quality could be obtained.
Utility of 2D Finite Element Simulations for Predicting Effective Thermomechanical Properties of Particle-Reinforced Composites
Authors: Makarian Kamran , Santhanam Sridhar
Published: January 2019

In the last two decades, researchers have implemented two-dimensional (2D) Finite Element (FE) simulations of particle-reinforced composites for various purposes, including prediction of effective properties and failure modes. The present work aspires to examine the validity of the hypothesis that 2D FE simulations can provide accurate predictions for various thermomechanical properties of high volume fraction (VF) particle-reinforced composites. For this purpose, the random sequential adsorption (RSA) algorithm is implemented to generate FE simulations of various composites. The uniqueness in the methodology of the present work is in the generation of FE simulation of composites with more than two material types as reinforcement, as well as thorough and concurrent comparison of multiple thermal and mechanical properties. The adequacy of the simulations is verified statistically, and the results are compared to predictions from established schemes as well as certain experimental findings. These comparisons show that the predictive power of 2D FE simulations is lower for elastic properties, and higher for coefficient of thermal expansion (CTE) and thermal conductivity of particle-reinforced composites. The findings of this research can guide the researchers in making better decisions for implementing Finite Element Method (FEM) for designing high VF composites.
Patellofemoral Pain Syndrome: Sensitivity Analysis of Muscle Parameters for Expedited Recovery Utilizing an OpenSim Model for Lower Extremities
Authors: Novotny Adam , Paliwal Manish
Published: January 2019

Patellofemoral pain syndrome (PFPS) is a musculoskeletal condition characterized by anterior knee pain. The symptoms associated with PFPS can be further aggravated through activities that increase patellofemoral compressive forces. Despite the number of mechanisms that are considered to contribute to this disorder, there is no consensus about its etiology, causing difficulty in prescribing the appropriate treatment or physical therapy. To properly evaluate PFPS, the influences of various muscles and their geometries on knee joint reaction forces for a human subject during a normal gait cycle were observed by conducting parametric analysis using OpenSim. The muscles that were seen to be most critical and have a potential effect in reducing the pain experienced at the knee joint are the soleus, iliopsoas, and gastrocnemius muscles. It was observed that individually increasing the length of the soleus and iliopsoas muscles from 75% to 125% of their default lengths resulted in decrease in knee joint reaction forces of up to 400 N (57%) in the x-direction and 600 N (40%) in the y-direction for the soleus and 550 N (38%) in the x-direction and 1000 N (29%) in the y-direction for the iliopsoas. It was also seen that by indirectly reducing the cross-sectional area of the gastrocnemius muscles from 125% to 75% of their default value resulted in decreases in knee joint reaction forces of up to 250 N (50%) in the x-direction and 500 N (42%) in the y-direction. Therefore, exercises should be advised to specifically stretch or strengthen the soleus and iliopsoas, and the gastrocnemius muscles should be rested. Pain and recovery time may be substantially reduced with the utilization of a targeted physiotherapy treatment plan. It can be coupled with longterm physiotherapy program for improving muscle fitness.
3D Construction of a Tilted Cuboid Mechanical Metamaterial
Authors: Yang Yunfang , You Zhong
Published: January 2019

Functional metamaterials are gradually becoming the frontier of scientific research and industrial applications. Among them, reconfigurable mechanical metamaterial with inbuilt motion capability could result in unusual physical properties such as shape tunability and programmable density and stiffness. Inspired by the transformable cuboid structure that was first investigated by Ron Resch, we proposed a tilted cuboid structure that can fold into a 3D configuration. By designing the individual building units, face angles and tessellation pattern, we are able to construct a series of reconfigurable structures with various shape, twist and permeability feature. Based on our approach, a configuration method to build multi-layer metamaterial is proposed, and it can be generalized to other tilted structures with different building units. The volumetric strains of different models are analyzed, and the result shows the metamaterial has a massive deformation ability as the maximum volume can be four times of the packaged volume. The tilted cuboid structure is highly flexible with variable stiffness and permeability, and can be used to develop metamaterials, large deformation devices and kinetic architectures.
Integrated Curvature Sensing of Soft Bending Actuators Using Inertial Measurement Units
Authors: Seibel Arthur , Schiller Lars
Published: January 2019

We introduce a sensor concept for an integrated measurement of the curvature angle of soft bending actuators using inertial measurement units (IMUs). In particular, IMUs are placed at both ends of the soft bending actuator, and the integrated magnetic sensors are used for small and the integrated acceleration sensors for medium and large inclination angles of the soft actuator’s bending plane. The experimental results show absolute measurement errors of up to 20° for small and less than 5° for medium and large inclination angles. Furthermore, we investigate experimentally whether the assumption of a constant curvature in our sensor concept is still fulfilled when the soft bending actuator is loaded by an external force at its free end. The results indicate that this is the case for loading masses of up to 30 g at large inclination angles.
A Gear-Chain Based Transmission for the Machine Elements Design Laboratory
Authors: Azzouz Salim , Bernard Guy
Published: January 2019

This project describes the collaboration of two instructors, one from the mechanical engineering department and one from the mathematics department with a group of mechanical engineering students to build and analyze a new type of transportation transmission. Current transmissions have torque limitations when working at various vehicle loading conditions. The ideal vehicle transmission is a continuously variable transmission that delivers optimum torque at any loading condition. The motivation for this research project is to design a new transmission that would increase the number of gear ratios using a chain element, and consequentially, increasing the number of available torques to achieve better overall vehicle performance. The new transmission consists of two planetary gears systems linked by a chain. It includes multiple inputs and outputs with the possibility of using one of the outputs to drive other engine components. The system is currently investigated for all possible gear ratios and usable torque configurations. The gear ratios are determined using Willis’s formula for planetary gear systems. All possible gear combinations are investigated and their gear ratios mathematically determined. A prototype was designed and built. It is being automatized, currently.
The Investigation of the Kinetic Energy of Slug in a Horizontal Channel Using VOF Method
Authors: Ashrafi Nariman , Ansari Mohammad Reza , Chegini Armin , Sadeghi Ali
Published: January 2019

In this article, two-phase slug regime in a duct with rectangular cross-section is investigated numerically, using the volume of fluid (VOF) method. Equations of mass, momentum and advection of volume fraction are solved accompanying k-∈ realizable turbulence equations. To ensure the creditability, numerical results have been compared with experimental results using same geometry. With occurrence of instability in the entrance of duct, Kelvin-Helmholtz condition satisfies and with increasing instability, slug phenomenon occurs. With closing the cross-section of duct, slug causes pressure gradient in it. Trapped air behind a slug transfers the momentum and increases the kinetic energy of slug. In this research the kinetic energy of a slug is investigated.
Capillary Force Driven Single-Cell Spiking Apparatus for Studying Circulating Tumor Cells
Authors: Amontree Jacob , Chen Kangfu , Varillas Jose , Fan Z. Hugh
Published: January 2019

The characterization of single cells within heterogeneous populations has great impact on both biomedical sciences and cancer research. By investigating cellular compositions on a broad scale, pertinent outliers may be lost in the sample set. Alternatively, an investigation focused on the behavior of specific cells, such as circulating tumor cells (CTCs), will reveal genetic biomarkers or phenotypic characteristics associated with cancer and metastasis. On average, CTC concentration in peripheral blood is extremely low, as few as one to two per billion of healthy blood cells. Consequently, the critical element lacking in many methods of CTC detection is accurate cell capture efficiency at low concentrations. To simulate CTC isolation, researchers usually spike small amounts of tumor cells to healthy blood for separation. However, spiking tumor cells at extremely low concentrations is challenging in a standard laboratory setting. We report our study on an innovative apparatus and method designed for low-cost, precise, and replicable single-cell spiking (SCS). Our SCS method operates solely from capillary aspiration without the reliance on external laboratory equipment. To ensure that our method does not affect the viability of each cell, we investigated the effects of surface membrane tensions induced by aspiration. Finally, we performed affinity-based CTC isolation using human acute lymphoblastic leukemia cells (CCRF-CEM) spiked into healthy whole blood with the SCS technique. The results of the isolation experiments demonstrate the reliability of our method in generating low-concentration cell samples.
Full Frontal Impact Comparison of Steel and Carbon Fiber Composite Front Bumper Crush Can (FBCC) Structures
Authors: Dixit Y. , Begeman P. , Newaz G. , Board D. , Chen Y. , Faruque O.
Published: January 2019

This study compares the deformation characteristics of steel and carbon fiber composite (CFC) front bumper crush can (FBCC) assemblies when subjected to a full-overlap frontal impact into a rigid wall. Both the steel and composite bumper tests were conducted using a sled-on-sled testing method. Several high-speed cameras (HSCs) and accelerometers were used to gather kinematics data. The applied forces were measured using a load cell wall. For each test, the collective set of data was filtered, sorted, and analyzed to compare the performance of the steel and CFC bumpers.

Similarities in Acceleration-Time plots suggested resemblance in the deformation patterns for both types of bumper systems. The difference observed in the velocity and displacement time-histories was because of the brittle nature of the composite material. The velocity-time history of the CFC FBCC had two distinct patterns, events suggesting adhesive bond failure between the bumper beam and the crush cans, which was validated through video tracking. Post-impact photographs showed a clear difference between the material behavior of composite and steel bumpers when subjected to high-velocity impact. The steel bumper beam was bent uniformly with intact, equally crushed crush cans. The composite beam was cracked in the middle and was detached from the crush cans.
A Variational Derivation of Equations of Motion With Contact Constraints Using SE(3)
Authors: Murakami Hidenori , Ono Takeyuki
Published: January 2019

For rigid-body systems subjected to non-holonomic constraints, a streamlined method is presented to derive a minimum number of analytical equations of motion. To illustrate the method, a rolling disk problem is considered.

In kinematics, an orthonormal coordinate system is attached to the center of mass together with additional coordinate systems introduced to define the connection path. For each coordinate system, a moving frame is defined by explicitly writing the coordinate vector basis and the position vector of the origin, whereby the attitude of the coordinate vector basis and the coordinates of the origin are compactly stored in a 4 × 4 frame connection matrix of the special Euclidean group, SE(3).

Contact velocity constraints are transformed to pfaffians to obtain the associated variational constraints.

In kinetics, the principle of virtual work is employed. The desired equations of motion are obtained by expressing the translational and angular velocities at the center of mass as the linear functions of the generalized velocities with the coefficients stored in [B]-matrix, and reducing it to [B*]-matrix after incorporating the contact constraints.

The method can be easily extended to multi-body systems with both holonomic and non-holonomic constraints.
Numerical Study on Apparent Permeability of Porous Media in Slip Gas Flows Based on Lattice Boltzmann Method
Authors: Liu Zhenyu , Mu Zhiyu , Wu Huiying
Published: January 2019

The unconventional gas reservoir has attracted more and more attention as the shale gas greatly expands worldwide energy supply, for which the gaseous fluid transport in complex porous domain is one important process as the shale gas is extracted. The apparent permeability of porous media is one important parameter in the related numerical model, however, its determination is still challenging. The apparent permeability varies with gas pressure, the porous media properties and gas–solid interactions based on the previous studies. For the slip gas flows, the velocity slip at the gas-solid interface in confined porous space is one significant difference compared with that on macro scale, which is caused by the gas rarefaction effect. In this work, a pore-scale LB model is established to simulate the gaseous fluid flow in the confined porous media. An effective curved boundary treatment is adopted for the porous surface and the validation test shows that the present model has superiority in capturing the slip phenomenon on the curved surfaces. Based on the numerical predictions, the different influential factors on the permeability of confined porous media are thoroughly studied, for which the gas rarefaction effect is considered.
Feasibility Study of Condition Monitoring for Some Event Around the Crosshead in a Reciprocating Compressor
Authors: Mori Yoshifumi , Saito Takashi , Mizobe Yu
Published: January 2019

The purpose of this study is to establish a new monitoring technique to quantitatively detect the states of the sliding and connecting portions, where it could be found that failures often occur. We proposed a monitoring method wherein a mathematical model and actual measurement data for the moving parts of the reciprocating compressor were used to construct a system that (i) monitors the state while the reciprocating compressor operates and (ii) predicts and diagnoses signs of damage. This paper reports on a case study involving experimental data acquired before and after failures occurred in the connecting parts of the connecting rod. The purpose is to assess how the parameter values differed between the two operating states. To equate (i) each natural frequency calculated from eigenvalue analysis based on the proposed model with (ii) each resonant frequency during operation corresponding to the natural frequency of bending, we define an error function for the identified problem, namely, the optimum problem. In this paper, it is assumed that the crosshead pin that attaches the connecting rod to the crosshead wears out, and the dimensions of the crosshead pin are processed. In the observational results, it was found that some parameter values had large differences, and the corresponding state change could occur around the crosshead. We demonstrated the possibility of detecting both types of changes in the parameter values and the deterioration in the parts for two different operating states by the proposed method.
Integrity Evaluation of Composite Cylindrical Structures
Authors: Du Jikai
Published: January 2019

The application of composite material in structures can not only lower the component weight but also improve the system performance through its tailorable thermal and mechanical properties. However, because of the harsh environmental conditions that such structures may encounter during operation, the successful applications of such structures cannot be realized without appropriate techniques for their structural integrity evaluation.

In this study, composite cylindrical structures consisting of composite and steel layers are being evaluated with X-ray diffraction technique and various ultrasound techniques. First, X-ray diffraction technique was applied for the quantitative determination of the residual stress in the steel layer. The influence of composite layer on the stress distribution was analyzed and how such residual stress study will improve the performance of the structure was discussed. Then various ultrasound techniques were applied for the detection of various defects, such as the defects at the surface and subsurface of inner steel layer, the different types of defects in the outer composite layer, and the defect, which is the most critical one, at the interface of steel/composite layer. During ultrasound evaluation, the composite material may not only increase the ultrasound attenuation but also change ultrasound traveling direction, and this can make the inspection more challenging. Theoretical calculations were carried out for the optimization of experimental parameters such as ultrasound frequency, incident angle, and focused ultrasound field calculation and so on. The limitations of ultrasound technique and the potential of other non-destructive techniques were also discussed according to experimental results.
Experimental Investigation on Boundary Layer Flow Under the Effect of Temperature Gradient in a Smooth Rotating Channel Using Hot-Wire
Authors: Li Gangfu , Tao Zhi , Wu Huijie , You Ruquan , Li Haiwang
Published: January 2019

This experiment measures the temperature and the velocity field synchronously in the boundary layer in a rotating smooth, wall-heated channel using hot-wire. The Reynolds number based on the bulk mean velocity and hydraulic diameter is 19000 and the rotation numbers are 0, 0.07, 0.14, 0.21, 0.28 and 0.35. Four streamwise stations (X/D = 4.06, 5.31, 6.56, 7.81) were investigated. To calibrate the parallel-array hot-wire probe, a heating section is added to the original wind tunnel that could only calibrate the hot-wire at room temperature. Different gas temperatures at the outlet could be obtained by changing the heating power of the heating section. The velocity profiles and the temperature profiles are obtained. It can be seen that the viscous sublayer also exists when the wall is heated, thus the viscous sublayer profile method is also valid when the wall is heated. It is found that the velocity profile near the leading side is more sensitive to the change of rotation number and X/D than the velocity profile near the trailing edge. The critical rotation number phenomenon of velocity profile has also been found in present work. By comparing with the previous work without the wall heated, the influence of both kinds of buoyancy under this condition is discussed. Some explanations are given for the experimental results.
Experimental Investigation on the Vibration and Noise Characteristics of the Vibration Damping Alloy Material
Authors: Ji Xiang , Chen Yong , Liu Hai , Yu Hanzhengnan , Wei Changyin , Yan Zhibiao
Published: January 2019

Due to the stricter roles of the government and the higher requirement of a comfortable automobile, the NVH (Noise Vibration and Harshness) performance of vehicles has become one of the most important traits at the automobile market. Considering the cost, it is more economical and practical to improve the NVH performance by using the vibration-isolating or noise-reducing materials. Vibration damping alloy as one of the new material has a promising prospect due to its great damping characteristics.

In this paper, the vibration-isolating and noise-reducing performances of the vibration damping alloy have been experimentally investigated in a semi-anechoic room. Frequency response function test has been carried with the test rod made of vibration damping alloy and 45 steel to calculate the damping ratio of the two materials based on the half-power bandwidth method. The radiation noise characteristics of the two test rods under different excitation forces have also been evaluated.

Conclusions drawn from the experiment suggested that the damping ratio of 45 steel rod were 0.0125 in vertical axial direction and 0.0165 in axial direction. While, the damping ratio of vibration damping alloy rod were 0.0236 in vertical axial direction and 0.0234 in axial direction, 89% and 42% higher than the 45 steel sample, respectively. With the increase of the exciting force, the radiation noise increased for both two materials, and the radiation noise level of the vibration damping alloy rod was much lower than 45 steel rod. And the difference between these two materials remained unchanged with the increase of exciting force. In addition, the duration of noise attenuation for vibration damping alloy rod was much shorter than the 45 steel.
Prediction of Gas Permeation in Polymeric Materials Used in Oil and Gas Industry
Authors: Nassr Nooshin , Siddique Zahed
Published: January 2019

An Arrhenius relationship is employed to develop a model for prediction of gas permeation in the polymeric materials. A permeation cell was designed to measure the gas permeation. The permeation of Helium was examined over a range of low to high temperature and pressure conditions. The results of the experiments were used to verify the accuracy of the prediction model.

The obtained model was successful in predicting gas permeation rate at two different pressures. The results showed that pressure’s effect is insignificant on models. The predicted results for different pressure were close, and both models can be used to obtain an approximation for gas permeation rate for the examined material where no experimental data exists.
Perception Thresholding for Noise Removal in Micrographs of Cellular Tissues Acquired by Fluorescence Microscopy
Authors: Manzur Saad , Shawon Md. Badiul Haque , Naznin Mahmuda , Faisal Tanvir R.
Published: January 2019

Plant petioles and stems are hierarchical structures comprising cellular tissues in one or more intermediate hierarchies displaying quasi random to heterogeneous cellularity that governs the overall structural properties. Exact replication of natural cellular tissue leads to the investigation of mechanical properties at the microstructural level. However, the micrographs often display artifacts due to experimental procedure and prevent representative spatial modeling of the tissues. Existing methods such as local thresholding or global thresholding (Otsu’s method) fail to effectively remove the artifacts. Hence, an efficient algorithm is required that can effectively help to reconstruct the geometric models of tissue microstructures by removing the noise. In this work, perception-based thresholding that conceptually works like human brain in differentiating noise from the actual ones based on color is introduced to remove discrete (within a cell) or adjacent (to the cell boundaries) noise. A variety of image dataset of non-woody plant tissues were tested with the algorithm, and its effectiveness in eliminating noise was quantitatively compared with existing noise removal techniques by Bivariate Similarity Index. The bivariate metrics indicate an enhanced performance of the perception-based thresholding over other considered algorithms.
Reproduction of Kinematic Behavior of Elastic Lamellae in the Thoracic Aortic Media
Authors: Tamura Atsutaka , Kato Yuya
Published: January 2019

The thickening of the aortic wall is a mechanical adaptation to the prolonged increase in intravascular pressure resulting from hypertension, which is regulated by the smooth muscle cell layer (SML) and the elastic lamina (EL). Herein, we built a simplified computational model of the aortic media composed of SML and EL and simulated the phenomenon of EL undulation or EL buckling at no-load condition (in vitro) by releasing compressive prestress assigned to the EL. Using the design of experiments approach, we found that the prestress assigned to the EL, the thickness of the EL, and a coupled or interspace connecting length between the SML and the EL are significantly influential factors in representing EL buckling at the unloaded state. We also found that the degree of EL waviness and the change in residual stresses within the SML and the EL are inversely correlated. Furthermore, by increasing the stiffness of the SML, we successfully reconstructed the disappearance of EL undulation at 25% stretch, replicating the dilation of a normal aorta under physiological loading conditions. It can be expected that these findings will help unveil the roles of the SML and the EL in maintaining the mechanical homeostasis of the arterial wall.
Photosensitivity of Monolayer Graphene-Base Field Effect Transistor
Authors: Goundar Jowesh Avisheik , Suzuki Ken , Miura Hideo
Published: January 2019

The optical properties and device physics of monolayer graphene under light is investigated in this study. In order to understand the change of the electronic behavior of graphene under light, it was necessary to study from the most fundamental layer with high quality. Thus, it became mandatory to develop a highly efficient, low-cost fabrication process for synthesis of high-quality monolayer graphene. The high-quality monolayer graphene was grown on a copper foil using a low-pressure chemical vapor deposition (LP-CVD) method at temperature of 1035°C for 10 minutes. Acetylene was used as the precursor gas for the synthesis of monolayer graphene. Thin Pt/Au films were, then, deposited on a silicon dioxide/silicon (SiO2/Si) substrate using electron beam (EB) lithography which served as source and drain electrodes of a transistor. The synthesized graphene was, then, transferred to a SiO2/Si substrate using PMMA (polymethyl methacrylate)-assisted method.

The quality of the synthesized graphene was validated using Raman spectroscopy. No significant D peak was observed in the Raman spectra of the synthesized graphene. This result validated the high quality of the transferred graphene. Next, the photo-sensitivity of G-FET was investigated under light source of color temperature of 2856 K at room temperature. The electron transfer characteristic of the fabricated G-FET was measured under dark and light illumination conditions. Finally, the graphene-based field effect transistor G-FET demonstrated an external photo responsivity of about 200 μA/W with a maximum photocurrent attained to be 0.2 μA at an incident luminance power of 1 mW. The active detection region of this sample was 1000 × 60 μm2.
Numerical and Experimental Studies on the Development of Variable Density Nanocomposites for Structural Applications
Authors: Pothnis Jayaram R. , Kalyanasundaram Dinesh , Gururaja Suhasini
Published: January 2019

Numerical and experimental studies performed to develop nanocomposites with varying carbon nanotube (CNT) alignment density within an epoxy matrix are presented. A 3-D numerical model has been developed that looks at the behavior of CNTs in epoxy resin subjected to non-uniform electric fields by explicitly accounting for electric field coupled with fluid flow and particle motion considering the transient resin viscosity. The transient nature of resin viscosity has been incorporated into the simulation study with data related to resin viscosity variation with time and temperature generated experimentally. The response of CNTs due to the induced dielectrophoretic force was studied using the numerical model. The model facilitated the design of an optimal electrode configuration for the processing of variable density composites. A computer controlled Arduino UNO based circuitry was developed to control supply of voltage to the electrodes during sample fabrication. The circuit was then integrated with AC voltage supply units and the electrode set-up for fabricating the variable density composite samples. Low weight fractions of CNTs (0.05 wt.% and 0.1 wt.%) in epoxy resin were used for the experimental work and preliminary experimental studies were conducted. Electrical characterization results of the variable density nanocomposites indicate over 100% and 30% increase in electrical resistance measured across sample widths in 0.05 wt.% and 0.1 wt.% CNT samples, respectively. The measured sample resistance values confirmed that variation in CNT alignment density was achieved across the samples.
Influence of Brain Cooling on Frequency Characteristics of the Epileptic Focus and its Surrounding Area
Authors: Kumano Saya , Saito Takashi , Uehara Kenyu
Published: January 2019

In this study, we examined the suppression effect of brain cooling on the epileptic focus and surrounding area. An epileptic seizure was induced in rats to obtain electrocorticography (ECoG) data when brain cooling was performed on the epileptic focus and its surroundings. Then, the frequency response characteristics were calculated by applying fast Fourier transform (FFT) and band pass filter to the obtained multichannel brain wave data. At this time, the frequency band calculated by the band pass filter was α waves (8.0–13.0Hz) and β waves (13.0–30.0 Hz) which were remarkably observed in epileptic seizure in the previous study, the analysis window of FFT was 4.095 seconds, and the overlap was 75%. As a result of comparing the calculated frequency responses for each rat, it was found that at the site where epileptic seizures were observed, power was reduced by cooling and suppressing effect was observed, whereas at the same time, the power increased at the site a few millimeters adjacent to the seizure site. This result suggests that epileptic waves suppressed by brain cooling might propagate to the surrounding area by a few millimeters.
Effect of Constrained Groove Pressing on Mechanical Properties of Nitinol Alloy
Authors: Padisala S. K. , Bhardwaj A. , Poluri K. , Gupta A. K.
Published: January 2019

Nitinol shape memory alloy is well known for its shape memory effect and super elastic effect. In the present work, the improvement of mechanical properties of nitinol alloy like yield strength, ultimate tensile strength and micro-hardness is discussed along with the study of evolution of micro-structure after every pass to extend the applications of shape memory alloys into high strength application areas. Severe plastic deformation processes are usually adopted for producing fine grain structures which improve the mechanical properties of a material. One such severe deformation process is constrained groove pressing, which is considered as one of the best severe plastic deformation techniques for sheet metals. The results of constrained groove pressing process on nitinol alloy show that the yield strength and the ultimate tensile strength have increased by about 3.6 times 2.5 times respectively, with an increment of 50% and 74% in micro-hardness after 1st pass of constrained groove pressing and 2nd pass of constrained groove pressing respectively. Microstructure shows increase in martensitic phase after constrained groove pressing processing. Increasing in twinning and grain boundary density can be observed in constrained groove pressing processed nitinol, which are the reasons for the tremendous increase in the strength of the alloy. Thus, the constrained groove pressing process on nitinol alloy can increase its range of application for high strength requirements.
GA Optimized Formation Control of Autonomous Underwater Vehicles
Authors: Karkoub Mansour , Romdhane Lotfi
Published: January 2019

In this paper, an optimization procedure is derived to find the best controller for the trajectory-tracking of an autonomous underwater vehicle (AUV) subject to uncertainties (e.g., current disturbances, un-modeled dynamics and parameter variations). The proposed algorithm is based on the dynamic model of the system and a recently proposed controller called Hierarchical Robust Nonlinear Controller (HRNC). The first objective is to find the best values for the controller gains to achieve trajectory tracking of the leader AUV. Starting from a random configuration, the leader AUV and the five followers make and keep a given formation all along the trajectory. A multi-objective optimization, based on genetic algorithms, is used here. A star formation with 6 AUVs is used as a case study to test the proposed algorithm. Simulation results show that the optimized controller gains led to successful formation keeping along the selected path with relatively minimum controller output toques.
Study on the Numerical Analysis of In-Line Type Subsea Separator for Liquid-Liquid Mixture Flow
Authors: Kim Youngju , Woo Namsub , Kim Hyunji , Han Sangmok , Ha Jiho , Huh Sunchul
Published: January 2019

Subsea separation is an attractive and economic solution to develop deep offshore oil and gas fields producing fluid without hydrate or wax. The subsea separation system should be reliable to ensure successful operation in a wide range of multiphase flow regime. A subsea separator can avoid or simplifying costly surface platforms of floating vessels, as well as being an efficient tool to enhance hydrocarbon production. One solution of interest is the separation and re-injection of water at the seabed to avoid bringing the water up to the surface facility. In this study, liquid-liquid flow characteristics inside in-line type subsea separation system are investigated for the design of subsea separation system. The separation efficiency of the subsea separator is determined through experiments that are the liquid-liquid phased separation. Also internal swirl element (ISE) modeling of the separator was optimized. The analysis results were utilized to improve the reliability and efficiency of the subsea separation system.
Study on Cutting Temperature Modeling of Machined Workpiece in End Milling In-Situ TiB2/7050Al MMCs
Authors: Xiong Yifeng , Wang Wenhu , Jiang Ruisong , Lin Kunyang
Published: January 2019

During metal cutting, it is well known that the cutting temperature has great influence on the machined surface integrity, especially on the residual stress and machining defects. At present, a lot of analytical modeling work has been done on the cutting temperature of tool, chips and workpiece machined by the side cutting edge during end milling process. To the workpiece surface machined by the bottom cutting edge, the study of temperature modeling is rarely reported. Besides, as a new kind of particulate metal matrix composites (MMCs) with improved mechanical and physical properties, the machining study of in-situ TiB2/7050Al MMCs is not many and no analytical temperature modeling of MMCs has been published up to now. Our study aims to establish an analytical cutting temperature model of workpiece machined by the bottom cutting edge in end milling in-situ TiB2/7050Al MMCs. In this model, the moving heat source method was applied. To meet the actual cutting process, the effect of heating time was also taken into account. With validation, the temperature model shows good agreement with experimental results. It was found that the heat partition ratio conducted from the shear plane heat source to the workpiece increased linearly as thermal number increased, due to the influence of increasing heat conducted into chip by the side cutting edge. The proposed cutting temperature model was of great significance for both the temperature modeling work of end milling and study of Al-MMCs.
Finite Element Analysis of the Load Factor and Design for Bolted T-Shape Flange Joints Consisting of Dissimilar Clamped Parts
Authors: Sawa Shunichiro , Sekiguchi Yasuhisa , Sawa Toshiyuki
Published: January 2019

In the present paper, the load factor for bolted T-shape flange joints where two dissimilar material (steel-aluminum) of T-shape flanges are clamped by two bolts and nuts under external tensile loadings is examined using Finite Element analysis. Furthermore, the effect of the distance C between the center of the bolt and that of T-shape flange on the load factor and a load when the interfaces start to separate are examined. In addition, the mechanical characteristics of bolted T-shape flange joints where two clamped parts are steel and aluminum are examined. The value of the load factor for steel-aluminum T-flange joint is a little bit larger than that for steel-steel T-flange joints. When the external tensile loads are applied to the bolted T-shape flange joints, the bolts are inclined and as a result, the bending moment occurs in the bolts. A maximum bending stress in the bolts is also shown and it is about 6% larger than the bolt stress due to the load factor. For verification of FEM calculations, experiments to measure the load factor and the maximum bending stress occurred in the bolts are carried out. The FEM results are in a fairly good agreement with the experimental results. Finally, based on the obtained results, a design method for bolted joints with dissimilar T-shape flanges is demonstrated for determining the nominal bolt diameter and the bolt strength grade. It is found that the contact stress at the bearing surfaces of aluminum T-flange is critical.