bluuebunny/crossref_metadata_2025 huggingface dataset:
Design of a Smart Glove Using Flexible Technology for Artificial Gripper
Authors: Nandikolla Vidya K. , Bochen Robin , Suhr Tristin
Published: January 2019

The paper presents the design of a smart glove with flexible sensors integrated with wireless technology to measure the signals of grabbing and grasping. The sensor technology is structured into three phases: sensor calibration, amplification and digitizer of the wearable sensors. The real-time raw data is collected, filters are designed to remove the noise and relay the information to the developed application via Bluetooth. The Bluetooth module communicates with an android mobile application through the Bluetooth networks known as the piconets. Piconets use a master/slave model with a Bluetooth module to control and send data that communicates with a smart device. The mobile application sends and receives information to/from the Bluetooth module and the mobile device. This allows the user to analyze the forces applied in each finger for various operations. The interactive glove interfaced with mobile technology provides gesture recognition and maps the finger orientation. The purpose of designing such a glove is to train the user how to improve their hand defense mechanism as the mobile device informs about the multi finger gripper control. To improve the quality of hand rehabilitation, the proposed design can provide physicians an efficient tool to evaluate the recovery of patient’s hand injury.
Thermal Shrinkage Behavior of Battery Separator
Authors: Yan Shutian , Deng Jie , Bae Chulheung , Xiao Xinran
Published: January 2019

Battery separators are thin, porous membrane of 20∼30 microns thickness. Polymer separators display a significant amount of shrinkage at elevated temperatures. It is difficult to quantitatively characterize the large shrinkage behavior with a free standing separator sample. This paper examines the use of a dynamic mechanical analyzer under tensile mode in measuring the coefficient of thermal expansion (CTE) of three commonly used separators.
Development of Chemotherapy System Using Plasma Activated Medium to Enhance PC12 Axonal Extension
Authors: Haccho Takanobu , Ichikawa Hiroshi , Yamamoto Koji , Morita Yusuke , Nakamachi Eiji
Published: January 2019

In recent years, plasma activated medicine using non-thermal atmospheric-pressure plasma (NTAPP) has attracted great interest for chemotherapy. In this study, we aim to develop a chemotherapy system with reactive species generated in a plasma activated medium (PAM) for PC12 treatment. We observe the morphology change of PC12 cells and evaluate the effectiveness of PAM and the reactive species on axonal-extension enhancement.

First, we measured the amount of reactive species, such as H2O2, NO2, and NO3 in PAM. Second, we confirmed the stimulation effect of PAM on PC12 by measuring the axonal extension length of a 72-h culture after PAM stimulation. Experiments were conducted under 20 conditions to find an optimal condition. Using the grid method, significant axonal extension was confirmed. Next, the optimal conditions to promote PC12 axonal-extension was determined using the response surface method. Promotion of axonal extension was not confirmed in the cell culture using only H2O2. As a result, we presumed that the enhancement of axonal-extension was induced by the coupling effects of NO2, NO3 and H2O2, which are active species produced in PAM. Finally, we were able to declare that PAM exhibits a selective cell activation property for the chemotherapy of the central nervous system.
Development of Stretch Stimulation Device for Three-Dimensional Culture of PC12 Cells
Authors: Imura Madoka , Sakiyama Ryota , Yamamoto Koji , Morita Yusuke , Nakamachi Eiji
Published: January 2019

Enhancement of nerve axonal extension by using the extracellular environmental stimulation were reported. In this study, we focused on the stretch stimulation, and developed a 3D cell culture system to mimic the in vivo extracellular matrices and investigated the fundamental mechanism of axonal extension enhancement.

Firstly, we fabricated the stretch stimulation device. The rat phenocromocytoma cells (PC12), the nerve-like cells, embedded in the collagen gel were poured into the stretch chamber. It was set in the stretch stimulation device, which could load the strain to the collagen gel. Secondly, we determined the structure of the stretch chamber to implement the uniform strain distribution in the culture region. Using the finite element (FE) analyses, we confirmed that the uniform strain is assigned in a region of 2.7 × 3.0 × 0.5 mm in the culture region, which is the candidate for the observation region. Thirdly, PC12 cells axonal extension under uniaxial cyclic stretch stimulation (4% strain, 1 Hz) of 24 hours was carried out. After 96 hours’ culture, we observed the 3D morphology of PC12 cells by the multiphoton excitation fluorescence microscope (MPM). Finally, we confirmed the availability of our stretch stimulation device and the enhancement effect of axonal extension.
Virtual Vibration Correlation Technique (VCT) for Nonlinear Analysis of Metallic and Composite Structures
Authors: Pagani Alfonso , Augello Riccardo , Carrera Erasmo
Published: January 2019

An important role in the design of structure is represented by the buckling analysis. The loading and service conditions, in which structures usually work, may significantly afflict their equilibrium state. This aspect often forces the design engineers to perform an accurate buckling analysis, in order to calculate critical loads of the structure. In fact, this critical load causes a sudden change of the structure, leading to a radical decrease in the loadcarrying capability. For these reasons, buckling analysis of beam-columns has been widely investigated in the past and recent years.

One of the most important experimental technology to calculate the critical buckling load of structures if represented by the Vibration Correlation Technique (VCT). It allows determining equivalent boundary conditions and buckling load for several types of structures and its strength is represented by the fact that it is a non-destructive methodology: essentially, the stability loads were determined by interpolating, until singularity, the natural frequency of the structure subjected to progressive higher loadings, without reaching the instability point. VCT is already widely used for beam, plate and shell structures.

This paper intends to assess a numerical simulation of the experimental data needed for the Vibration Correlation Technique. The solution proposed is developed in the domain of the Carrera Unified Formulation (CUF), according to which theories of structures can degenerate into a generalized kinematics that makes use of an arbitrary expansion of the generalized variables. Moreover, in order to reproduce results obtained in an experimental way, when large displacement and rotations may occur, geometrical nonlineatities have been taken into account. Thus, a finite element approximation is used along with a path-following method to perform nonlinear analyses.

Different types of structures have been analyzed, made with metallic and composite materials, and some results are compared with others found in the VCT literature. Results show how this methodology can well evaluate the natural frequencies on the structure in a geometrical nonlinear framework, and so also the critical buckling load.
Dynamic Behavior of a Solid Oxide Steam Electrolyzer System Using Transient Photovoltaic Generated Power for Renewable Hydrogen Production
Authors: Saeedmanesh Alireza , Colombo Paolo , Brouwer Jack
Published: January 2019

The purpose of this study is to investigate the dynamic behavior of a Solid Oxide Steam Electrolyzer (SOSE) system without an external heat source which uses transient photovoltaic (PV) generated power as an input to produce compressed (to 3MPa) renewable hydrogen to be injected directly into the natural gas network. A cathode-supported crossflow planar Solid Oxide Electrolysis (SOE) cell is modeled in a quasi-3D thermo-electrochemical model that spatially and temporally simulates the performance of a unit cell operating dynamically. The stack is comprised of 2500 unit cells that are assumed to be assembled into identically operating stacks, creating a 300kW electrolyzer stack module. A 15-minute resolution dataset for operation of PV generation was obtained from a database that archives PV power dynamics of systems on the University of California, Irvine campus. The dataset (comprised of data for approximately 4.1 MW of peak solar power) was scaled to a maximum of 450kW of PV generation. For the designed 300kW SOSE stack (thermoneutral voltage achieved at design steady state conditions), powered by the dynamic 0–450kW output of PV systems, thermal management and balancing of all heat supply and cooling demands is required based upon the operating voltage to enable efficient operation and prevent degradation of the SOSE stacks. The PV generation dataset was analyzed to obtain a day in which the PV generated power has its highest dynamic behavior (a cloudy day) and another day in which the PV generated power and energy is maximum (a sunny day). Dynamic system simulation results show that the SOSE system is capable of following the dynamic PV generated power for both of these days while the SOSE stack temperature gradient is always maintained below a maximum set point along the stack for both days. The system efficiency based upon lower heating value of the generated hydrogen is between 0–75% and 0–78% with daily hydrogen production of 94kg and 55kg for sunny and cloudy days, respectively.
The Automatic Basketball Rebound System
Authors: Smith Thomas , Nandikolla Vidya K.
Published: January 2019

In the sport of basketball, it is important to practice shooting the ball to develop the skill of making the shot in the basket at a high efficiency. Making shots at a high efficiency allows the player to succeed at a high level in the sport. The main focus of the paper describes the design and development of an automatic basketball rebound (ABR) system. The developed ABR provides a system that will launch the ball back to the player at any position on the court within a 50-foot radius. This is accomplished by a variable spring loaded launching mechanism that will compress a spring, depending on the players location, to generate the appropriate force required to launch the ball back to the player. The novel launching mechanism developed is mounted to a rotary table that ensures the launching mechanism is in the correct orientation with the player once the ball is launched. The player is outfitted with an inertial measurement unit to track their position using a method known as dead reckoning. This information is relayed back to a microcontroller that determines the system response. The ABR system is made from lightweight materials and is compact such that it is easy to move around compared to its predecessors.
A Novel Nonlinear Time-Frequency Strategy for Stabilizing Inverted Pendulum Cart System
Authors: Zhang Zilong , Suh C. Steve
Published: January 2019

The stabilization of the inverted pendulum-cart system (IPCS) is a classical problem in the control engineering. The study of IPCS is motivated by its applications to the balancing of rocket boosters and bipedal robots. IPCS represents a class of nonlinear, under-actuated, and unstable system hard to be controlled in real-time. In this paper, a novel nonlinear time-frequency control (NTFC) strategy is applied to stabilize an inverted pendulum mounted on a cart. The proposed controller design is adaptive and employs discrete the wavelet transform and filtered-x least-mean-square (Fx-LMS) algorithm to realize the control in real-time. Using the wavelet transform, the adaptive controller is demonstrated to inhibit the deteriorations of the time and frequency responses simultaneously before the residual oscillation is too broadband to be controlled. The presented controller consists of two adaptive finite impulse response filers that operate on the wavelet coefficients: the first one realizes the online identification and provides a priori information in real-time while the second one realizes a feedforward control and rejects the uncontrollable input signal based on the first FIR filter. The equation of motion is derived based on the Newton’s Second law of motion and the model id simulated in MATLAB for verification. A number of commonly used control methods for the stabilization of the IPCS are investigated and evaluated against the proposed NTFC strategy. The simulation results show that the proposed control strategy is feasible for balancing the IPCS for a large, tilted initial angle within a short time interval and strongly robust to external impact and perturbation in real-time.
Solution to Optimize the Airfoils Shapes Placed Into a Supersonic Viscous Flow
Authors: Radulescu Victorita
Published: January 2019

To improve the airfoils performances placed in supersonic flow is proposed a method of optimization for their shapes, in order to minimize the effect of the landing vortices. The theoretical modeling starts with the Navier-Stokes equations applied for thin layers, supplemented with additional conditions related to the profile shape. For a proper estimation of efficiency and responses at different flow regime’s conditions, were considered four aerodynamics airfoils, with different shapes and functioning characteristics. Two of them are special shapes of supersonic profiles and the other two deduced by theoretical assessments with an efficient behavior at high Reynolds numbers. The main purpose of this selection was to identify the essential aspects needed to be considered in numerical modeling of the airfoil’s wing shapes, as to assure an optimization of their behavior for different flow conditions. In the supersonic flow, the cross-sections of the wings are thin profiles, mainly symmetric, as to reduce the drag coefficient and to maximize, as possible, the lift coefficient. A supplementary method for the shape calculation of the aerodynamic profiles with small curvature, based on the Fredholm integral equation of the second kind, with a good behavior in the supersonic flow, is presented. Some aspects referring to unsteady flows and air compressibility are considered, as to simulate as much as possible the real, natural conditions. All profiles were tested, firstly, into a subsonic wind tunnel at incidences between 00 – 40 for different values of wind velocity, and secondly, into a supersonic wind tunnel, at the same incidences. The objective was to better understand and analyze the main factors, which influence the aerodynamic of shapes with curvature, and to assure an optimization of their behavior. The purpose of testing these profiles was to estimate a solution to improve the main characteristics, especially into the trailing and leading edges zones. There were also considered the effects of the attack angle, the influence of the wind velocity, air viscosity, and the shape’s curvature, on the vortices development. The obtained results allow a better functioning in supersonic flow regime, by eliminating the adverse pressure gradient and the boundary layer separation, assuring an optimum behavior especially into the leading edge zone.
Post-Graduation Assessment of the Effectiveness of an Industrially Sponsored Senior Design Capstone Course
Authors: Moreno Vito , Weber Bryan , Barber Thomas
Published: January 2019

Results of a survey of recent graduates who completed the Mechanical Engineering Senior Design Capstone course at the University of Connecticut are presented. Student perspectives on level of effort, effectiveness of course outcomes, and value of the course in their current jobs are presented. Overall results suggest that the industrially sponsored projects together with the class lectures have provided valuable experiences.
Period Motions in a Periodically Forced, Damped Double Pendulum
Authors: Luo Albert C. J. , Guo Chuan
Published: January 2019

In this paper, period motions in a periodically forced, damped, double pendulum are analytically predicted through a discrete implicit mapping method. The implicit mapping is established via the discretized differential equation. The corresponding stability and bifurcation conditions of the period motions are predicted through eigenvalue analysis. Numerical simulation of the period motions in the double pendulum is completed from analytical predictions.
Dexterous Hybrid Robotics for High Precision Applications
Authors: Jackson Nolan , Crowther Mitchell , Shin Minchul
Published: January 2019

Robotic grippers are useful in designing prosthetics and manufacturing. “Robotic hands often fall into two categories: simple and highly specialized grippers often used in manufacturing, and general and highly complicated grippers designed for a variety of tasks.” Ramond et al. [1] Within these two categories there are two main categories of research. These are hard structure and soft structure robotics. Hard structure robotics rely on a mechanical design with a motor or actuator to move a hard-linked part. Soft structure uses a mechanical design, soft material and a pneumatic pump to create the desired movement. The soft material is designed in a way that when it is pumped full of a fluid (i.e. air) it has a specific deformation. Hard robotics have an advantage in their ability to output a large force, but soft robotics have increased degrees of freedom. Dexterity (readiness and grace in physical movement) is another advantage over hard robotics. This project focuses on the process of designing actuators that can feasibly be used for devices falling into either of the two main categories of robotics. Such an actuator could be effectively implemented toward simple applications such as manufacturing-style gripping devices to advanced applications found in modern human prosthetics or areas where high dexterity combined with a delicate touch are required. The simulations show that the designs created work within a pressure range of 0.5 PSI to 1 PSI. This low pressure does not output a lot of force. The high dexterity and small air compressors needed make it a good design for use in areas like manufacturing or medical. If a stronger material was applied to these designs allowing the designs to handle higher pressures these designs could output much higher forces. This increase would make the designs more usable in areas like prosthetics and advanced robotics.
Optimization of Nano-Texture Parameters of CdTe/CdS Thin Film Solar Cells
Authors: Smay Joshua , Rashwan Ola , Then James
Published: January 2019

The thin film solar cells (TFSCs) are becoming more widely implemented due to their light weight, lower cost, and flexibility when compared to the conventional monocrystalline silicon wafer solar cells. Common materials used in the TFSCs today are amorphous silicon (a-Si) and microcrystalline silicon due to their abundance. However, these materials suffer from decreased absorption efficiency especially in the infrared range due to the sub-micron thickness of the absorber. Cadmium Telluride/Cadmium Sulfide (CdTe/CdS) is a promising candidate for TFSC material due to the near ideal, direct band gap of the CdTe, which allows it to be implemented without suffering greatly from decreased absorption efficiency. Nano-texturing is a widely researched and implemented way to increase the absorption of TFSCs. In this project, the wave optical analyses for the wavelength range of 300–1100 nm were executed using ANSYS High Frequency Structural Simulator (HFSS) to study the interaction of the geometric parameters of the nano-structures in CdS/CdTe TFSCs. A 3X3 factorial design of experiments was implemented to investigate 3 different levels of the height (H), diameter (D), and period (Pd) for a conical shaped nano-texture pattern and to study their effect on the absorption and the short circuit current (Jsc). A total of 27 different combinations were investigated. It was found that the model with H = 1000 nm, D = 1000 nm, and P/D = 1 had the highest Jsc of 26.66 mA/cm2, a 29.14 % increase from the planar control cell. In addition, it was noted that when the P/D ratio is 1, an increase in both height and diameter will increase Jsc. Finally, when the height was 200 nm, an increase in the diameter has little to no effect on Jsc. These findings are important to TFSCs manufactures to better design the nano-texturing implemented in TFSCs.
Virtual Teach Pendant Interface for Android Cellphones (VTPAC)
Authors: Ferri Giulia A. , Walter Scott E. , Tennakoon Asiri , Djuric Ana M.
Published: January 2019

The objective of this research is to develop a Virtual Teach Pendant for Android Cellphones (VTPAC) that is able to communicate with the robot model in the Visual Components software ⌈1⌉ ⌈2⌉. The VTPAC is a force multiplier that allows users to gain valuable teach pendant experience in labs with few robots, and makes the actual real-world robot time more valuable. It is also like a graduated driver’s license where the student must prove some proficiency with the VTPAC before being allowed to get behind the wheel.

The VTPAC will be used to operate the real robot system too and will allow people to be trained without using real robotic systems in very safe environment. The VTPAC can be used for industrial training and can be integrated in the academic programs, especially for online courses.

In this research, the Fanuc LR Mate 200iC robot and the Visual Components software have been selected as a case study. These choices were made because of the easy access to the Fanuc LR Mate 200iC and this interface by reason of it can control the robot the same way as the Teach Pendant in the real world.

Using the robot kinematic theory to understand the Teach Pendant commands, the code was developed such that it respects the operating mode of the robot and all the security operations needed. For the VTPAC development we used Python to communicate with the Visual Components software to work as a client for the software. This can allow users to utilize its own cellphone as the teach pendant and the software as the robot, having a more real experience in a safe environment. The VTPAC has been implemented and tested successfully.
The Reynolds Stress in Turbulence From an Alternate Perspective
Authors: Lee T.-W.
Published: January 2019

We present a unique method for solving for the Reynolds stress in turbulent canonical flows, based on the momentum balance for a control volume moving at the local mean velocity. A differential transform converts this momentum balance to a closed form, with the longitudinal component, u’2 and the mean velocity, U as its constituents. Validations with experimental and computational data in simple geometries show quite good results. Using this perspective, determination of the Reynolds stress in terms of computable turbulence parameters is rendered possible.
Thermal Analysis of a Subscale Flux Focusing Magnetic Gearbox
Authors: Modaresahmadi Sina , Khalesi Javad , Kadel Joshua , Williams Wesley
Published: January 2019

Magnetic gears are non-contact means of torque transmission which utilize the interaction of magnetic fields in place of the meshing teeth of mechanical gears to achieve a change in rotational speed and scale up/down the torque. A subscale magnetic gearbox featured a radial flux focusing arrangement consisting of three main rotors in the active region called inner, cage and outer rotors. In this arrangement, ferromagnetic cage rotor poles modulate flux between the inner rotor and outer rotor permanent magnets to achieve the gear reduction. Replacing the solid metal bars with laminated stacks for the cage modulating pieces as well as retaining pieces of the inner and outer rotor magnets reduces eddy current losses in the axial direction, a main source of losses in magnetic gears, while preserving the magnetic flux directed in the radial direction. Both of these features are key for overall system performance.

Given the potential of demagnetization of the permanent magnets and damage to the components at high temperature, multiphysics thermal analysis is conducted on a subscale flux focusing magnetic gearbox to predict temperature distribution and thermal stresses. A conjugate heat transfer (CHT) method is used in a 3D academic code, FLUENT, to predict heat flux and the coupled non-adiabatic external flow field and temperature field on the inner, cage and outer rotor with a Finite Volume Method (FVM). Thermo-elastic behavior of the laminated components are assigned through anisotropic materialistic characters in a finite element method (FEM), where the thermal and centrifugal stresses are calculated.
Real-Time Distance Courses to Improve Satisfaction and Competence: A Case Study of International Professors and Local Students
Authors: Núñez Martha Elena , Rojas Juan-Carlos
Published: January 2019

Distance education is an alternative to traditional education made possible by technology. The essential components for remote teaching are easy access, usefulness, social interaction, and flexibility of time and place. Tecnológico de Monterrey (ITESM) has recently implemented a program to promote the visit of foreign professors to Mexico, this initiative is called PEV (foreign visitor professor). One way to get more benefits from the program is to invite them to give distance classes once their presence year in Mexico has ended.

This case study describes student satisfaction with the theoretical-practical courses taught through the real-time distance learning method in the School of Architecture and Industrial Design. The determining factors in the student approval were defined as: the learners’ inclination to take similar courses, the quality of contact between teacher and students, feeling inspired by the professor, and recommending the course to other students. The primary factors of novelty, flexibility, and utility of the remote format were measured using a Likert-type scale. The findings revealed a notable level of acceptance by students. Specifically, the course format factor was positively valued by the sample. These findings are significant to Latin American and international universities because they describe one way to improve their distance or remote teaching and learning offerings.
Acoustic Signal Analysis for Prediction of Flank Wear During Conventional Milling
Authors: Roney Travis , Bauccio Anthony , Shaffer Derek , Lorson Paige , Ragai Ihab , Loker David , Nikhare Chetan
Published: January 2019

In recent years, the investigation of the acoustic signals (AS) produced from different machining processes have primarily focused on the ultrasonic frequency range. The objective of this work is to propose a novel technique for predicting the flank wear condition of a tool and ultimately tool failure (insert chipping) during the process of conventional face milling. Preliminary experiments suggest that the spectral content of audible acoustic emission (AAE) signals could be used to predict the cumulative flank wear in real time for an indexable carbide insert during the milling process. The experiments conducted for this study suggest a strong correlation between the magnitudes of the AAE in the selected frequency range, and the amount of wear on the insert.
Research on the Weak Signal Detection of Bearing Fault Based on Duffing Oscillator
Authors: Hao Long , Liu Dan , Liu Fei , Wang QingXin , Liang Lin , Xu GuangHua
Published: January 2019

In this paper, chaotic system is applied to identify and extract the weak signals of bearing early fault which are often submerged in strong background noise. Chaotic system is an effective method in weak signal detection because of its properties of noise immunity and sensitivity to the weak periodic signal. However, chaotic system is not completely immune to noise in critical chaotic state. Aiming at this problem, four indicators are used to evaluate the detection performance of Duffing oscillators. Then, the influence of Duffing oscillator parameters on the four indicators is studied in detail and a new method is proposed to improve the detection performance of Duffing oscillator. The simulation and experimental results show that the proposed method can accurately obtain the characteristic signals of early bearing fault in a lower signal-to-noise ratio (SNR) situation.
Smartphone-Based Device for Monitoring Chemical Pollutants in Water
Authors: Ozeh Samuel , Nnanna A. G. Agwu , Ndukaife Justus C.
Published: January 2019

There remains a need for a cost-effective, sensitive and on-site analytical technique which requires minimal technical skills for monitoring chemical contaminants in water. This research work presents a smartphone-based colorimetric detection of trace chemical pollutants in water. Components of the Hue, Saturation and Value (HSV) color space within a global region of interest (ROI) of analytes’ image were utilized in developing an algorithm for the quantitative detection of target ions. Calibrations were conducted with Chromium (VI) and Nitrite analytes ranging between 0–250 ppb and 0–3000 ppb respectively. The calibration equation and coefficient of correlation as obtained were HS2 = −0.00918C+6.46003; R2 = 0.9997 and HS2 = −0.00584C+4.85119; R2 = 0.98228 respectively. The smartphone-based monitoring system was utilized to systematically obtain the concentration of target ions in arbitrary solutions. Limits of detection of the system for Nitrite and Chromium (VI) which are within USEPA specification were approximately 285 ppb and 16 ppb respectively. Appreciable agreements between conventional and proposed techniques were obtained with a maximum percentage difference of 8.21% in the concentration of an arbitrary sample.
Uniquely Designed Solar Tube in a Natural/Forced Mini-Water Heating System
Authors: Abdelmessih Amanie N. , Mohammed Siddiq S.
Published: January 2019

Solar power is a clean source of energy, i.e. it does not generate carbon dioxide or other air pollutants. In 2017, solar power produced only 0.6 percent of the energy used in the United States, according to the Energy Information Administration. Consequently, more solar energy should be implemented, such as in solar water heaters.

This research took place in Riverside, Southern California where there is an abundance of solar energy. In house uniquely designed and assembled solar tubes were used in designing a mini solar water heating system. The mini solar water heating system was set to operate under either natural or forced convection. The results of running the system under forced convection then under natural convection conditions are reported and discussed in the article. In addition, comparison of using two different solar water storage systems are reported: the first was water; the second storage medium was a combination of water and gravel. Since water heaters are extensively used for residential purposes, this research mimicked the inefficiencies in residential use and is compared with ideal operating conditions. The performance of the different cases studied is evaluated.
Thermal Modeling of Concentrated Photovoltaic Thermal System at Different Operating Conditions
Authors: Alam Shah , Yelamanchili Rahul
Published: January 2019

Concentrated photovoltaic thermal system is a reliable solar energy system that utilizes sunlight of higher concentration on a photovoltaic cell to generate energy that is superior to conventional solar systems due to fewer space requirements and high electrical and thermal efficiencies. The primary objective of this thesis was to test two operating conditions of the concentrated photovoltaic thermal system and find the condition that delivers maximum output when compared to the other. The first condition tested in this research included variable velocity of water flowing in the cooling channel while a constant amount of heat flux was applied on the photovoltaic cells. The second tested condition included constant velocity of water flowing in the cooling channel while varying the amount of heat flux applied on the photovoltaic cells. Through mathematical modeling, that includes, thermal modeling and energy analysis was carried out for the concentrated photovoltaic thermal system along with simulations of the system that were performed using a three-dimensional finite element analysis software called Ansys Workbench (Fluent). The results from this research provide a useful path in improving the efficiency of the concentrated photovoltaic thermal system.
Fatigue Crack Growth Rate Studies on Stainless Steel Welds
Authors: Thomas Manuel , Prakash Raghu V. , Sundararaman Ganesh , Muthukumaran Vasudevan
Published: January 2019

The low carbon, nitrogen enhanced SS 304 L(N) stainless steels are one of the most potential candidates for the structural members in chemical industries and powerplants operating at hostile environments of temperature and corrosion. In service, the structural members fabricated using welding process, when subjected to a combination of mechanical load and elevated temperature can fail by fatigue. The Welding of Austenitic stainless steels using Tungsten Inert gas (TIG) is often limited by the depth of weld penetration, which can be achieved during a single pass. This necessitates for the use of multiple passes resulting in weld distortion and generation of residual stress. The Use of an electronegative flux (Activating flux) during the TIG welding (A-TIG) is known to enhance the weld penetration, thereby reducing the number of passes.

The present study evaluates the fatigue crack growth in stainless steel weldment (304L(N) welds) joined using conventional Multipass TIG welding and Activated flux TIG welding at 673K. Compact Tension (C(T)) specimens having a width of 50.8 mm and a thickness of 4 mm were extracted from the location of heat-affected zone (HAZ) and weld metal (WM) for A-TIG and MP-TIG configurations. From the micro-structural evaluation of A-TIG welds, it is noted that high heat input in a single pass has favored the formation of coarse equiaxed grains along the weld center. The use of multiple passes at reduced heat input has resulted in the formation of finer grains, with the orientation of grains changing along each weld pass interface. This finer randomly oriented grains has resulted in increasing crack path resistance through the MP-TIG welds compared to A-TIG welds. Thus from a view point of fatigue crack growth, due to the presence of fine grains, conventional Multi-pass weld is superior compared to A-TIG, but in cases where there is a creep or creep-fatigue combination, the A-TIG weld may prove to be useful.
Effect of Discrete Sectional Bonding of Cellular Core on Impact Performance of Square Tubes: A Finite Element Study
Authors: Ali Muhammad , Ohioma Eboreime , Alam Khairul
Published: January 2019

Thin walled members such as square tubes are commonly used in vehicle’s frontal chassis to provide protection and damage attenuation to the passenger cabin in the case of impact loading. These structural members undergo progressive deformation under axial loading. The type of deformation mode is critical as it defines the overall configuration of force-displacement curve. There are different types of deformation modes for square tube under axial loading. Likewise, cellular structure exhibit distinct deformation modes under in-plane loading. The work presented here investigates the effects of partial or discrete bonding of cellular core structure on deformation modes of square tubes under axial loading. The results show that discrete bonding of cellular core with the tube has significant effect on progressive deformation of tubes and therefore, presents an opportunity to re-configure force-displacement curve for improved protection of automobile structures under impact loading.
Effect of Nonlinear Characteristic of the Gas Turbine Engine Fuel System With Hardware-in-the-Loop
Authors: Chen Jinwei , Li Jingxuan , Sun Shengnan , Zhang Huisheng
Published: January 2019

Fuel supply system, the regulation system for fuel delivery to the combustor, is one of the most important auxiliary systems in a gas turbine engine. Commonly, the fuel supply system was always simplified as a linear system. In fact, gas turbine engines almost use a hydromechanical main fuel control system which consists of electro-hydraulic servo actuator and fuel metering unit. These components have several nonlinear characteristics such as hysteresis, dead zone, relay, and saturator. These nonlinear characteristics can directly affect the performance a gas turbine engine. In this paper, a three-shaft gas turbine engine was taken as a research object. Firstly, a mechanism model of the fuel control system considering the nonlinear links was developed based on the hydro-mechanical theory. Then, the effect of dead zone-relay characteristic of the servo amplifier in electro-hydraulic servo actuator was analyzed. The results show that the dead zone width has great effect on the dynamic performance of the gas turbine engine. The fuel flow rate will be oscillating with small dead zone width. The parameters of the gas turbine engine will be stable with the increase of dead zone width. However, the larger dead zone width causes the hysteresis and the increase of the dynamic response time. At the same time, an improvement method with a two-dimensional fuzzy compensation was proposed. The results show that the fuzzy compensation can effectively solve the oscillation problem caused by the dead zone-delay. Finally, a Hardware-In-the-Loop (HIL) system is developed which is based on an electro-hydraulic servo actuator facility and a real-time software component of the gas turbine engine. An experiment is conducted on the HIL test rig to validate simulation result. The results show that the experiment matches well with the simulation results.
Reproduction Analysis of Injury Condition Using Finite Element Modeling of the Head in Cases With Traumatic Higher Brain Dysfunction Caused by Traffic Accidents
Authors: Hayashi Shigeto , Nakadate Hiromichi , Zhang Yuelin , Mekata Kojiro , Yamashita Haruo , Nakayama Shinichi , Kohmura Eiji , Matsui Yasuhiro , Ji Hong , Aomura Shigeru
Published: January 2019

Following head trauma caused by traffic accidents, many patients are unable to completely recover their social functions due to higher brain dysfunction although they are able to return home. To predict the onset and severity of post-traumatic higher brain dysfunction, the visualization of responsible injury is considered urgent. In this study, we focused on five patients with higher brain dysfunction following head trauma caused by traffic accidents to establish a method for quantitatively evaluating higher brain dysfunction. The injury conditions were reproduced on the basis of multibody dynamic and collision analyses using finite element (FE) modeling of the human head to determine mechanical responses inside the cranium of these patients. The strain on the frontal lobe generated by an injury condition was suggested to contribute to the onset of attention disturbance during the chronic phase of medical treatment. Reproduction analysis of the injury conditions using FE modeling of the head could predict the onset and severity of traumatic higher brain dysfunction.
Investigations on Unsteady Flow Excitation and Mechanical Performance of Last Turbine Stage Long Blade Using Fluid-Structure Interaction Method
Authors: Li Jun , Li Zhigang , Song Liming , Deng Qinghua
Published: January 2019

Detailed numerical investigations on the unsteady flow excitation characteristics and mechanical performance under unsteady surface pressure of last turbine stage long blade are conducted by applying sliding interface method and fluid-structure interaction approach. Unsteady aerodynamic performance of turbine stage is analyzed through solving the three-dimensional Reynolds-Averaged Navier-Stokes (RANS) solution and k-ε turbulent model using commercial CFD software ANSYS-CFX. The computational domains include last stage stator domain, rotor domain, shroud domain and curved diffusor. Unsteady pressure on long blade surfaces in every time step is transferred to the mechanical grids of long blade after interpolated in the fluid-solid interface. The mechanical performance of long blade with damper shroud and part-span connector (PSC) is obtained using finite element method (FEM) while considering the unsteady aerodynamic load and nonlinear contact between adjacent damping tip-shroud and PSC. The numerical results show that static pressure on long blade surface presents obvious periodic fluctuation; with the decrease of mass flow, blade loading reduces obviously and separation vortex appears in the diffusor and extends to the rotor passages; the frequency of separation vortex is about 126 Hz; the maximum displacement and maximum Von-Mises stress of long blade both show periodic features.
An Algorithm for Similar 3D Model Difference Examination Using Geometric Matching
Authors: Yin Yue , Guo Lianshui
Published: January 2019

In this paper, a new algorithm for similar 3D CAD model difference examination based on geometric matching is presented. Firstly, using the boundary representation (B-rep) method, the two 3D models are decomposed into two sets of surfaces, each with an attributed adjacency graph (AAG) which is established using adjacency relationship of corresponding surfaces. The vertices of the AAG are set as the geometric information about surfaces (i.e. surface type, area). The edges of the AAG present the adjacency between surfaces, and the attribute information (i.e. the type and length of edges, the angle between two adjacent surfaces) is also stored in the AAG. Secondly, the surface similarity between two models is calculated according to their types, areas, composition edges and topological relationships. At the same time, the similarity matrix which stores the surface similarity coefficients is generated to find the geometric and topological optimal matching surfaces. Then, in the AAG, with the corresponding vertices of the optimal matching surface pair as the center, the remaining surfaces of two models are quickly and optimally matched according to the topological connections and similarity coefficients while the unmatchable ones are defined as added or deleted surfaces. Finally, differences between the two models are evaluated by analyzing and comparing the geometric attribute information about the matched surfaces.

In order to validate the effectiveness and feasibility of the proposed algorithm, a software prototype for similar model difference examination has been developed. The effectiveness and feasibility of the algorithm have been verified by engineering applications through the industrial needs. The results show that this algorithm can effectively compare the differences among different design iterations and demonstrate its potentials for a wide range of engineering design iterations examination problems.
A Combined GCMC and FVM Simulation Method for CO2 Adsorption in 13X Zeolite Adsorption Bed
Authors: Wang H. , Bai J. Q. , Qu Z. G. , Wang Y. , Zhang Y.
Published: January 2019

A multi-scale method combining the finite volume model (FVM) considering Darcy-Brinkman formulation with grand conical Monte Carlo (GCMC) is built to study the process of CO2 adsorption in 13X zeolite particle bed. The saturation adsorption capacities and adsorption heat in FVM method are calculated by Langmuir model and linear fitting formula, respectively. The GCMC method is used to obtain the parameters of Langmuir model and linear fitting formula. The multi-scale method overcomes the shortcomings of the saturation adsorption capacities restricted by level of experimentation or empirical formula. The relationship between adsorption heat and adsorption amount is also obtained. The value of adsorption heat is no longer treated as the constant value or obtained from the empirical formula. The effects of velocity, particle size, porosity and thermal conductivity of particle on CO2 adsorption in13X zeolite particle bed are investigated. The results show that the saturation adsorption time decreases with increased velocity, porosity and thermal conductivity of particle, while increases with increased particle size. The peak of temperature difference between the solid and gas phase increases with increased inlet velocity, porosity and particle size, while decreases with thermal conductivity of particle. The temperature difference trends uniformity and the peak of temperature difference moves towards to the outlet of adsorption bed with adsorption time processing. The adsorption bed with a higher inlet velocity, porosity and thermal conductivity of particle, and smaller particle size is recommended to improve the adsorption bed performance.
System Wear Life Estimation Under Uncertainty
Authors: Pourmostafaei Mohammad , Pourgol-Mohammad Mohammad , Yazdani Mojtaba , Salimi Hossein
Published: January 2019

In this paper, a new model is proposed for system degradation evaluation under sliding wear failure mechanism. This model estimates the material loss by progression of sliding distance. This model is generated by considering physical and geometrical aspects of system under wear mechanism. Several sets of experimental data are used for validation of the presented model. These experimental data are related to pin-on-disc test of Tungsten Carbide pins. These sets of data include initially conformal and non-conformal contacts. One set of data of pin-on-disc test by ASTM-G99 standard is used for additional validation of the model and for investigation of normal load effects on the parameters of presented model. Finally, uncertainty analysis is done by Monte-Carlo simulation to determine the variations of the predicted wear caused material loss.
Dynamic Comparison of a 3-Degrees-of-Freedom Parallel Manipulator With Multiple Dry Clearance Joints and With Lubricated Joints
Authors: Zhang Haodong , Zhang Xianmin , Zhang Xuchong , Zhan Zhenhui
Published: January 2019

This paper compares the dynamic response of a 3-degree-of-freedom (3-DOFs) parallel manipulator with multiple dry clearance joints and with lubricated joints. For this purpose, a methodology developed on Newton–Euler equations is proposed to study lubricated joints in the parallel manipulator, which involves the hydrodynamic forces and impact forces in the constrained equations. Specifically, the hydrodynamic forces are based on the Reynolds’ equation of an infinitely long lubricated joint. Dynamic simulations are presented through the dynamic parameters of a planar parallel manipulator (3-PRR, the underline of the P represents the actuated joint, P and R represents prismatic and revolute pairs respectively), which has six revolute clearance joints and three ideal prismatic joints. The results of the comparison show that the lubricant makes significant difference and greatly improves the dynamic performance of the parallel manipulator with multiple revolute joints. More periodic states are observed from the dynamic behavior of the parallel manipulator with lubricated joints, making the manipulator easier to drive. All results demonstrate the usage of the procedures which contain the hydrodynamic force model of multiple lubricated joints in non-linear DAEs of a 3-DOFs parallel manipulator.
Numerical Study of Forced Convection in Different Fluids From Stationary Heated Cylinders in a Square Enclosure
Authors: Mishra Srishti , Tomar Mukul , Ahmad Adeel , Jain Satvik , Kumar Naveen
Published: January 2019

This paper performs a numerical study of forced convection heat transfer in a square enclosure with four identical stationary cylinders with single inlet and outlet ports. The ratio of the diameter of the cylinder to the length of the enclosure is kept constant at 0.1 with a fixed spacing between the cylinders. The enclosure walls are adiabatic while the cylinders are maintained at a constant temperature. The governing equations are solved for laminar, steady state and incompressible flow for different fluids namely air, water, and ethylene glycol. The study aims to determine the effect of varying Reynolds number (5 ≤ Re ≤ 100) and fluid properties (0.7 ≤ Pr < 200) on heat transfer rate and flow characteristics. The results of the study are presented in terms of streamlines, isotherm contours, and surface-averaged Nusselt numbers. The 2-D modeling and simulation have been conducted using ANSYS 16.0.