bluuebunny/crossref_metadata_2025 huggingface dataset:
Wear Behavior of Grinding Wheels With Superficial Cooling Channels
Authors: Capela P. , Carvalho S. F. , Costa S. , Souza S. , Pereira M. , Carvalho L. , Gomes J. R. , Soares D.
Published: January 2022

Grinding wheels are used in manufacturing industry to shape and finish different types of materials. To achieve this purpose, the wear resistance of grinding materials and the capacity to promote wear on the opposing surface determine the performance of the grinding part. During the grinding operations high temperatures are developed in the wheel/piece contact which can cause several problems like working material microstructural changes, internal defects (fissures...). In the last years, superficial structured wheels have been developed in order to reduce contact temperature and improve the grinding efficiency and the quality of the produced surface.

In this work, two types of channels structures were produced on the surface of a vitrified alumina abrasive composite with: hexagonal and spiral geometries (active area of 95.3 and 91.6%, respectively). The obtained composites produced were characterized in terms of physical properties (density and porosity) and geometric channel features. In order to evaluate the changes on the wear rate and surface morphology pin-on-disc wear tests were performed under lubricated conditions at constant load (20 N) and sliding speed (0.5 m.s−1), at room temperature. An alumina rod (∅5 mm) was used as counterface material creating particularly hard contact conditions. The wear rate of both mating surfaces was measured by gravimetric method. The worn surfaces were characterized by SEM analysis and the tribological results were correlated with the physical properties of the composites and the introduced cooling channels. The dominant wear mechanisms, as identified by SEM analysis, were fine scale abrasive wear of the protruding load carrying particles, which is featured by the formation of wear flats, together with debonding of ceramic particles from the composite contact surface. Comparing with traditional wheels (without cooling channels), a decrease of the wear rate on disc side of 35 and 42% was obtained for, respectively, spiral and hexagonal channel geometries. On the alumina opposite counterface, the wear rate increases 10 and 47% for, respectively, hexagonal and spiral geometries. A significant improvement on the abrasive performance (a wear rate decreases on the abrasive wheel and an increase on the counterface) was achieved with the addition of the two types of channel geometries. The best combination of results (composite and counterface) was obtained for the spiral configuration of the cooling channels (grinding ratio of 0.86).
Water Fuel Development: Part 1 - Clean Energy Production From Water Splitting High Temperature Electrolysis Process in Hydrogen Internal Combustion Engines
Authors: Abhulimen Kingsley E.
Published: January 2022

A novel technology model is presented that simplifies the technical requirements to produce hydrogen and clean energy from water splitting high temperature electrolysis process. Thus the model developed was applied to progress research in water based /hydrogen Internal Combustion Engines (ICE) with potentials of meeting the carbon footprints targets. Thus, the hydrogen (H2) from water splitting high temperature electrolysis process when reacted with CO2 produces methane (CH4) in their thermodynamic ratio to combust internal combustion engines and power plants. The thermodynamic simulation data derived from Aspen Plus software environment was used to simulate volume–temperature expansion at high pressure which has been applied to further water based/hydrogen internal combustion engine at different thermodynamic temperature requirements of 25°C, 100°C, 400°C, 800°C and 2000°C. A seamless and safe transition from fossil based economy to hydrogen economy is now feasible with new insights in thermodynamics theory where water as a raw material that could power the next hydrogen internal combustion engines and hydrogen power plants for future energy industry offer a cheaper and more sustainable fuel.
Design, Modeling, and Fabrication of a Ventilator Prototype - A Successful Student Project Story
Authors: Yeong Haoyee , Iloeje Francis , Kindomba Eli , Folorunso Sunday , Li Yafeng , Zhang Jing
Published: January 2022

In this work, we use a group project approach for a group of undergraduate students to design and develop a mechanical ventilator, in response to the COVID-19 pandemic. A student group project composed of a team of undergraduate students has successfully designed and fabricated a mechanical bag valve mask (BVM) ventilator prototype. It is lightweight with a single controller is driven, capable of volume adjustment, inexpensive, open-source, and designed for ease of fabrication, installation, and operation by the average user. The ventilator prototype also consists of 3D printed components and stored bought hardware. A finite element model was developed to analyze the deformation of the bag valve mask. Finally, the ventilator system is fully tested functioning properly.
Solitary Waves in an Array of Nonlinear Oscillators With Time-Periodic Damping and Stiffness Coefficients
Authors: Talebi Bidhendi M. Reza , Mohammadpanah Ahmad
Published: January 2022

The localized nonlinear responses of a chain of nonlinear pendulums with time-periodic damping and stiffness coefficients are investigated. The existence conditions and stability of the solitary waves are revisited for the aforementioned system. In essence, the parametrically driven discrete Klein-Gordon equation with time-periodic damping coefficient is converted to a damped parametrically driven discrete nonlinear Schrodinger equation using the method of multiple scales. The numerical simulations show how the stability and characteristics of the solitary waves are modified when the periodically modulated damping coefficient, which is either synchronized or asynchronized with the time-periodic stiffness coefficient, is added. In practice, time-periodic damping coefficient can be treated as a new way to tune the characteristic of the solitons (i.e., required threshold of the soliton activation and the period of oscillations) in the nonlinear periodic structures. This modification may provide some insights towards the control of the energy localization phenomena in nonlinear periodic structures with time-varying coefficients for efficient energy transport/management applications.
On the Fatigue Properties of 3D Steel Structures Welded Onto Ceramics
Authors: Allameh Seyed M. , Alexander Douglas , Miller Roger , Lenihan Avery , Allameh Hadi
Published: January 2022

Fabrication of prototypes and custom-made parts, made of various metals, has become possible by additive manufacturing. Like any new technology, reliability of the products is of utmost importance, especially, when it comes to life-sustaining structures or for applications where human life is at stake. A less common method of making 3D metallic object is by 3D welding. This method is more appropriate for structures where dimensional and esthetic characteristics of the structures are of secondary importance. An example is steel rebar in concrete where it requires rough corrugated surfaces of the rebars. This walled metallic structures, used especially for loadbearing applications, where load is not fixed will require investigation of fatigue properties. Conventional testing methods may not be appropriate for small cross sections. To address this problem, microtensile testing allows characterization of mechanical properties of small structures as thin as a few millimeters. Past work on the monotonic and cyclic properties of microsamples extracted from weldments made on metallic substrates has shown superior tensile strength and enhanced fatigue resistance compared to the base metal. It is interesting to see how the results would be different if ceramic substrates were used. This study utilizes a gantry type 3D printer, equipped with the gun of a MIG welding machine to fabricate steel weldments on ceramics using 3D welding technique. The process involves starting of the arc from a grounded piece of metal, then continue the motion of the gun and guide the motion of the molten metal pool in desired direction, maintaining the continuity through the solidifying bead. Weldment samples fabricated by this technique are then machined by a CNC mill to extract microscale dog-bone-shaped samples with a width of 200 micron and a gage length of 1000 micron. The top and bottom surfaces of the samples are polished to a mirror finish and subsequently the microsamples are mounted in the grippers of an Electropulse 1000 Instron load frame. Monotonic and cyclic loading mechanical tests in tensile mode are conducted and data are collected and plotted in terms of stress-strain as well as stress-life curves. These results are then compared with those of samples made by 3D welding of steel-on-steel substrate. Since the cooling rate of molten metal on steel substrates differs from that of ceramic substrate, fatigue properties may be different too. The implications of the reliability of reinforcement steel bars printed by 3D welding will be discussed.
Thermal Performance Analysis of Multi-Layer Thermal Energy Storage Tank Using Different Phase Change Materials
Authors: Azam Md. Ali , Hasan Mamun Mohammad Arif
Published: January 2022

A thermocline thermal energy storage (TES) tank is the key element of storing thermal energy for concentrated solar power (CSP) plants. This paper focuses on the numerical analysis of the single-phase thermal energy storage (TES) and the two-phase latent heat thermal energy storage (LHTES) for single-layered and multi-layered phase change materials (MLPCMs) using molten salt, FLiNaK, a eutectic mixture of 46.5%LiF, 11.5%NaF, and 42% KF as the heat transfer fluid. The heat transfer module for the computational domain is analyzed using the Dispersion-Concentric model which is based on energy equations and is solved by the finite element method. The results of the TES were compared with that of an existing numerical study in the literature, and they were found to be reasonably in agreement. The high thermal conductivity and specific heat capacity offered to the LHTES by the PCMs result in the best charging and discharging thermal cycle. The study helps us to understand the thermal behavior of temperature inside the tank for different PCMs and from the comparative thermal analysis of the study, it is possible to choose the best PCM among the alternatives.
Comparative Evaluation of Some Energy Policies in Abu Dhabi Using EnergyPlan Program
Authors: Al Naimi Moza Salim , Ali Mohamed I. Hassan
Published: January 2022

Energy planning is a key-factor in establishing framework for any kind of regulation in the energy sector. Considered to be a major instrument of energy policy planning is affected by allocation of energy resources, technological, environmental, and economical factors. Looking to the UAE Energy 2050-Plan, we find two main goals: delivering clean and inexpensive energy by raising the share of renewable energy in the energy mix from 25% to 50% by 2050, and reacting to climate change by reducing greenhouse gas emission produced by conventional power generation by 70%. The aim of this research is to evaluate Abu Dhabi’s energy system by comparing various policy development scenarios in the context of the recent integration of renewable and nuclear resources into the grid using real data. In this paper, a quantitative analysis of the Abu Dhabi energy sector is modeled with several scenarios to drive regional objectives and policies plans. This research employs deterministic hourly simulation that generates hourly analyses of the energy system, with consideration of 2020 as a reference year. Evaluation of modeled scenarios from the standpoint of annual carbon dioxide emissions and annual cost are presented and analyzed. Future research should consider uncertainty in nuclear power delay and availability.
Ultrasonic Characterization of Biomimetic Porous Scaffold Using Machine Learning: Application of Biot’s Theory
Authors: Hodaei Mohammad , Maghoul Pooneh
Published: January 2022

A two-dimensional infinite length porous slab is employed to simulate biomimetic porous scaffold. The pores of slab are saturated with a relatively low and high viscous fluids such as air and bone marrow. Ultrasonic waves based on the Biot-JKD formulation travel through the porous slab and create viscous exchanges between the skeletal frame and the fluid. The Biot-JKD formulation focuses on the parameters, biomarkers of the biomimetic porous scaffold, which are sensitive to the transmission and reflection signals. These parameters include porosity, tortuosity, viscous characteristic length, Young’s modulus, and Poisson’s ratio. An artificial neural network (ANN) based on a set of the biomarkers is rendered to model the transmitted and reflected waves from the porous slab. The validation of the proposed analytical approach and released artificial neural network is evaluated by the pertinent literature. The output of the artificial neural network, the transmitted-reflected waves, is inversely applied to the analytical expression to estimate the biomarkers associated with bone regeneration. The results show that for a medium filled with a relatively high viscous fluid the longitudinal waves are more prone to estimate mechanical properties of the medium such as Young’s modulus and Poisson’s ratio while the transverse waves, in addition to longitudinal waves, are essential to estimate the physical properties of the medium including porosity, tortuosity, and viscous characteristic length. Furthermore, it is also concluded that for the medium filled with a relatively low viscous fluid such as air the longitudinal waves alone is able to estimate the biomarkers, which reduce significantly the computational efforts.
Design and Structural Analysis of a Lifting Platform for Hydrotherapy Pool
Authors: David N. V. , Darjat M. Danial
Published: January 2022

Hydrotherapy is a supervised exercise session conducted in a specially designed swimming pool to induce healing health conditions against arthritis, inflammation and other ailments. Hydropool is a pool intended for such aquatic therapy whereby the users are seated in special-chairs on top of a platform that will be slowly submerged into the pool. However, existing platform structure and hoisting mechanism of hydropools are mostly physically strenuous for disabled people. Besides that, the cost of the lifting systems is often high owing to the sophisticated hydraulic or pneumatic apparatus and materials used. Thus, it is essential to design and analyze a hydropool platform and lifting mechanism to overcome these limitations. This study presents the numerical analysis of a 1200 mm (width) by 1015 mm (length) platform structure, and a scissor mechanism to lift the platform from a 1750-mm deep pool. The structure comprises nine individual components including base, scissor links, supporting and connecting links, leadscrew, platform, fence, bolts and nuts. The design objective is to minimize mass at optimum load carrying capacity with a reasonable safety factor. A few design options are considered to achieve this objective. A virtual model of the selected design is created using SolidWorks®. Finite element analysis (FEA) on the model is conducted using the ANSYS® workbench in static structural mode to evaluate the von Mises stresses and total deformations of the platform when a maximum load of 2943 N is applied vertically on the structure. The structure is made of SS316, which has a yield strength at 0.2% offset of 205 MPa as per the ASTM A276/A276M standard. The FEA results showed that the maximum von Mises stress of 67.9 MPa is obtained at the scissor link component of the structure. The corresponding maximum total deformation is 1.33 mm. The safety factor is found to be equivalent to 33.1% of the yield strength of SS316 at the maximum applied load. These observations indicate that the platform structure and scissor-lifting mechanism are safe under the loading conditions used in the simulation.
Effect of Manufacturing Process Tolerances on MEMS Vibratory Sensor Dynamics
Authors: Khan Nabeel , Agarwal Anurag , Harrison Tyler , Spicer Dean , Ahamed Mohammed Jalal
Published: January 2022

In this paper, a solid disk resonator is designed for manufacturability inside a wafer-level sealed cavity with fusion-bonding process. The device is then simulated using finite element analysis with a variety of manufacturing process tolerances to determine the effect of these variations on the performance of the resonator. It is shown that radial offset of the resonator due to misalignment during bond strongly affects in altering the operating frequencies of the resonator. The design approach considering manufacturing tolerances presented in this paper can be beneficial for high precision MEMS inertial sensor development.
Collaborative Robotics and Ergonomics: A Scientific Review
Authors: Di Marino Castrese , Tarallo Andrea , Vitali Andrea , Regazzoni Daniele
Published: January 2022

Collaborative robotics, or Human-Robot Collaboration (HRC), is a challenging topic characterized by multidisciplinary approaches. Many researchers are facing this innovative manufacturing system studying several aspects such as task allocation, facility layout problem and timing. Above all, one of the most important issues in collaborative robotics is the wellbeing of the operator collaborating with the robot system during the different phases of the process.

The added value of a collaborative workplace respect to the manual and automatic workplaces is strictly correlated to a safe and ergonomic interaction between the operator and the robot. Indeed, the combination of robot and operator skills lead to a higher level of accuracy and flexibility. Thus, assessing operator’s working conditions requires the acquisition, eventually in real time, of relevant parameters such as posture, movements, and interactive tasks. This may require the adoption of existing metrics proposed by standard evaluation guidelines, as well as the introduction of new or modified prescription to consider the presence of the robot. The ergonomics analysis in collaborative robotics is evaluated by considering both physical and cognitive aspects of the operator during the interaction with the robot.

The research work aims to carry out a scientific bibliometric literature review (BLR) about the ergonomics analysis of collaborative workplaces, and to identify methods and tools for the physical and cognitive ergonomics assessment that can be adopted in collaborative robotics. The search has been accomplished using the Scopus database by means of a set of key words specifically defined to investigate the ergonomics in the collaborative robotics. The review provides a sharp classification, a critical analysis of the most relevant contributions in this field so that emerging trends for future development can be defined and discussed.
Experimental Investigations Into Ionic Liquid-Based Nanofluids for Machining Difficult-to-Cut Materials
Authors: Singh Ramandeep , Sharma Varun
Published: January 2022

In any machining operation, cutting fluid is required to reduce the friction and heat generated between the tool-work interfaces. Reducing the cutting fluid level and their sustainability is a significant challenge associated with machining processes. In this study, the influence of Al2O3 nanoparticles on the Ionic Liquid (IL)-based cutting fluid is investigated. For performing it, six varying ILs (ammonium-based and immidazolium) were mixed with Al2O3 nanoparticles, and their lubricating behavior (viscosity, wettability, and thermal) were measured. Viscosity studies were conducted at temperatures ranging from 303–393 K, while thermal and wettability studies were conducted at room temperature. The experimental results of the study show that nanoparticles improve the thermophysical and lubrication properties. Jatropha Oil (JO) + Tetrabutylammonium bromide IL + Al2O3 shows the best results among the samples prepared. It shows an increase in viscosity by 17.87%, an increase in thermal conductivity by 30.5%, and a decrease in the contact angle by 32.8%, making it suitable for machining operations. Machining experimentation shows that the developed cutting fluids provide better performance in terms of reduction in cutting forces, surface roughness, coefficient of friction, and increase in shear angle compared to dry machining.
On Additive Manufacturing of Rib Fracture Fixation Implants: The Role of Lattice Design
Authors: Judkins Lauren , Gupta Richa , Gabriele Christine , Tomonto Charles , Hast Michael W. , Manogharan Guha
Published: January 2022

Rib fractures and chest flail injuries are life threatening injuries that often require surgical treatment using metal (e.g. titanium) fracture reconstruction plates and screws. Current implant designs do not account for the variable stiffness present in human ribs and are much stiffer than the native bone, causing undesirable clinical outcomes. In this preliminary study, groups of latticed test plates were designed with a body centered cubic (BCC) lattice and porosities ranging from 36–86%. Porosity was altered by changing lattice strut thickness between 0.225–0.425 mm and unit cell length between 1, 2, and 3 mm. The test plates were fabricated using an established laser powder bed fusion additive manufacturing process. Flexural strength (4-point bending) tests were performed at a strain rate of 1.3 mm/min to characterize changes in bending stiffness and strength. It was found that implant stiffness could be decreased by 15.7% (p = 0.068) by decreasing strut thickness from 0.425 to 0.225 mm and increasing unit cell length from 1 to 3 mm. The results of this preliminary experiment serve as guidelines for the design of full-sized rib fracture reconstruction plates that contain a gradient lattice with varied mechanical properties to better match the behavior of intact ribs.
Multi-Physical Coupled Simulation on Fuel Cooling Shell of Electric Fuel Pump
Authors: Yan Qingtao , Wang Bin , Ye Zhifeng
Published: January 2022

In commercial aviation industry, reduction of aircraft emissions is an urgent priority. Engine manufacturers in particular have worked long and hard to improve each component of the engine. MEE (More Electric Engine) is a new engine system concept that seeks engine efficiency improvements and emissions reduction in fuel burn and CO2. The key concept of the MEE involves the architecture for the electrical power generation by the engine and changing the power source for accessories from mechanical/hydraulic to a fault-tolerant electric motor. Due to its contribution to fuel burn reduction, electrification of the engine fuel pump system is a primary issue. The MEE motor-driven fuel pump is usually called electric fuel pump. There are several technical challenges for the design of the pump, including high power-weight-ratio and reliability. However, when the electric fuel pump delivers and regulates fuel into the combustor, the motor-driven pump generates much heat especially at high delivery pressure or flow rate, which deteriorates the running condition, life, and safety of the pump and even the engine. Thus, it is an urgent need to take reasonable heat dissipation measures for the motor cooling. Modeling techniques and characteristic study for heat dissipation is indispensable to cooling scheme design and optimization. Heat dissipation of the motor mainly involves heat generation calculation and heat dissipation scheme. It is necessary to minimize the heat generated by the motor loss. On the other hand, it is also necessary to improve the heat dissipation capacity of the motor as much as possible from the perspective of cooling performance. In order to obtain accurate heat dissipation characteristics of a fuel-cooling shell of an electric fuel pump, a multi-physical coupled model is built. The heat dissipation characteristics of the shell are numerically simulated under typical conditions. The results show that the loss of the stator/rotor core increases proportionally with the rotation speed, while the permanent magnet loss increases exponentially with the rotation speed. The temperature distribution of each part of the permanent magnet motor and fuel cooling shell is obtained. The fuel flow rate through the shell directly impacts the heat dissipation intensity, but the dissipation efficiency decreases with the increase of the flow rate. Based on the multi-physical coupled model, the effects of different parameters on the cooling are obtained, which proves the necessity of the model proposed in the paper when characterizing the heat distribution inside the pump.
Design Methodology of Gerotor Hydraulic Machines for Mechatronic Applications
Authors: Puliti Marco , Tessari Federico , Galluzzi Renato , Tonoli Andrea , Amati Nicola
Published: January 2022

In mechatronic applications such as electro-hydrostatic actuators, gerotor machines are often preferred over other technologies due to their high efficiency, low wear, low noise, and compactness. The design approach for hydraulic machines, either for motoring or pumping applications, involves the definition of different geometrical parameters, which affect their performance. Thus, the designer is often left without a clear design method to adopt. In this perspective, the presented research aims at providing a general design methodology of gerotor machines for their integration into high-efficiency mechatronic devices. In particular, the study focuses on the analytical and numerical characterization of the optimal tooth aspect ratio and maximum eccentricity between gears. Indeed, these two features are often left to the experience of the designer or are selected with empirical formulations. Our method is validated by means of numerical data from computational fluid-dynamic models to assess the performance of the hydraulic units.
Nondestructive Eddy Current Array (ECA) Technique for Stress Corrosion Cracking (SCC) Detection and Assessment
Authors: Taheri Hossein , Jones Cameron Alexis , Hossain Md Shahjahan
Published: January 2022

Many structures and mechanical components are under a combination of loading (stresses) and some kind of corrosive environmental operational condition which is called Stress Corrosion Cracking (SCC). Tubes in cooling water services, geothermal, and nuclear equipment are among the equipment which are subject to SCC. Since the SCC occurs at stresses within the range of typical design stress, it can cause catastrophic failures without a significant indication in structural integrity beforehand. Efficient Nondestructive Inspection (NDI) during the operational life of the structures can prevent such failures by providing accurate information regarding size and characteristics of the SCC flaws. Since majority of SCC defects occur in surface and near surface regions of metallic components, electromagnetic NDI (Eddy Current) is proved to be a promising inspection technique. In this study, Eddy Current Array (ECA) methodology was used for assessment of SCC generated in steel samples in a laboratory setup. ECA as an advanced eddy current NDI uses an array of eddy current coils to provide the scanning image of the inspection area. Prefabricated notches and SCC after a period of load-corrosion application to the samples were detected and characterized. Accuracy and repeatability of the results showed the efficiency of ECA for SCC characterization.
Modeling Discharge Spark Ignition Using Zero Dimension Thermodynamic Model and Experimental Power Measurements at Various Pressures
Authors: Shaffer James , Zare Saeid , Askari Omid
Published: January 2022

Laminar burning speed calculation at high pressures is challenging because of unstable surface conditions at large flame kernel diameters. It is therefore desired to take these measurements at small dimensions (i.e., during and immediately after the ignition discharge process) when the flame kernel is smooth and stable. Taking accurate measurements at these sizes is challenging because the kernel growth rate does not only depend on the chemical reaction but also on other phenomena such as energy discharge, as well as radiative and conductive energy losses. The effect of these events has not been adequately assessed, due to the generation of ionized gas (i.e., plasma). In order to better understand the effect of the ignition plasma in this work, spark ignition in air for 1–5 atm of pressure is studied. Understanding the ignition event and modeling its behavior is important to capture accurate combustion measurements at pressures pertinent to the advanced high-pressure engines and technologies. The relationship between the electrical energy supplied to the spark and the thermal energy dissipated within a gas mixture has been studied. This work relates the electrical discharge power to the volume of the ignition kernel measured via schlieren imagery. Voltage and current data are also captured as the input to a thermodynamic model which is used to predict the volume versus time data of the spark event. The model, which utilizes measured electrical power, thermodynamic properties of ionized air, and radiation losses in air show agreement with the experimental kernel measurements in terms of overall shape of the volume data within the measured kernel uncertainty. With these results and further experimental validation the present model is considered to represent the relationship between the electrical spark power and the measured ignition kernel volume. Future work will be done to determine inaccuracies present in the arc discharge regime as well as the effectiveness of the model in combustible media.
Investigation of New Alternate and Conventional Materials for Manufacturing High Pressure Turbine Disk
Authors: Sureshkumar Vyshak , Mourad Abdel-Hamid I.
Published: January 2022

Key to sustainable aviation is to find an efficient way to optimize the design of an aircraft and its parts irrespective of its size. Innovation of new materials with exceptional mechanical properties with reduced overall weight can contribute substantially towards a greener environment. During each operating cycle of an aircraft engine the blades of gas turbine are subjected to elevated temperature along with high levels of stress, especially in the high-pressure region. Another factor that overlaps this condition of quasi steady state are the induced stresses due to vibrational load by the local perturbations.

The main objective of this study is to identify the alternate materials that could be used as a replacement for the conventional materials. Based on the loads endured by the blades during the operation of the engine a selection criterion for the materials are characterized. These parameters are then used to identify the potential materials for manufacturing the high-pressure turbine disk using Granta Edupack software.

The manufacturing routes play an important role in the structure of the material. The paper discusses common manufacturing routes for both conventional and alternate materials along with its effect on the properties of the material based on cast and wrought or ingot metallurgy, powder metallurgy, mechanical and electrochemical method. The process of manufacturing of these superalloys and how they affect the chemical compositions of these materials are also discussed.
Design and Modelling of SCARA Robot Variant
Authors: Tummalapalli Manjeet , Ouyang Puren , Bahri Johnny
Published: January 2022

The SCARA robot has been extensively used for industrial applications. The motivation behind this research is to propose a SCARA variant as an alternative, with the popularity and applications of a SCARA robot. The main objective is to relocate the vertical prismatic joint and study the computational dynamics of the SCARA variant and the performances. The SCARA variant has been analyzed for the forward and inverse kinematics based on the transformation matrix method.

The dynamic model for the SCARA variant has been developed by using the Lagrangian method. The dynamic model is compared to the standard SCARA, it has been found that the dynamic models are very similar apart from the mass inertia and Coriolis matrices having terms in columns 2 & 3 exchanged. In this paper, linear and nonlinear trajectories, such as straight line, ellipse, and circular trajectories have been selected in the simulation study. Consistent results for torque requirements have been observed with the linear trajectory having the least values, followed by ellipse, and the circular trajectory.
Mathematical Modelling of Semi-Solid Electrodes for Flexible Lithium-Ion Batteries
Authors: Zakri Waleed , Fagehi Hassan , Alhadri Muapper , Abutaleb Ahmed , Farhad Siamak
Published: January 2022

Flexible Li-ion batteries (LIBs) have a strong oncoming consumer market demand for use in wearable electronic devices, flexible smart electronics, roll-up displays, electronic shelf labels, active radio-frequency identification tags, and implantable medical devices. This market demand necessitates research and development of flexible LIBs in order to fulfill the power requirements of these next-generation devices. In this study, the performance of semi solid anode for flexible Lithiumion battery was investigated through a mathematical model in order to reduce the number of experiments and to achieve the desired energy capacity of the battery. This model is a multiphysics three-dimensional heterogeneous model where all necessary transport phenomena including the charge and mass transfer and electrochemical reactions are considered at continuum mechanics level. COMSOL Multiphysics software is used to solve governing equations numerically using a finite element method. This model is for a half-cell simulation, and by using experimental results obtained in the lab. The maximum specific discharge capacity of the simulation Graphite/Li half-cell and LCO/Li reached up to 248(mAh/g) and 128(mAh/g), respectively, compared to the values received in the experimental test of ∼240 (mAh/g) for Graphite/Li and 120 (mAh/g) for LCO/Li. Overall, the simulation results were in acceptable agreement with those of the experiment. Parametric study was also performed to study the effect of adjustable parameters on the performance of both half cells. The difference in the discharge capacity was observed showing higher values at higher cell temperature and lower c-rate.
Geothermal Heat Exchanger Performance With Nanofluids Containing Ceramic MgO and Al2O3 Particles
Authors: Barua Himel , Younessi Sinaki Maryam , Farhad Siamak
Published: January 2022

A geothermal heat exchanger (GHE) uses the geothermal energy for heating or cooling of residential places during winter or summer. Two different designs of GHEs, the straight-pipe and coiled-pipe designs, are evaluated in this study, and the effect of nanofluid as the working fluid is investigated. For this purpose, a mathematical model is developed, validated, and used to predict the temperature gain, heat gain, exergy gain, and pressure loss of the working fluid for different concentration of additive ceramic nanoparticles (Al2O3 and MgO) into the working fluid. It is shown that the coiled-pipe design has better performance compared to the straight-pipe design for GHEs. It also shown that how the temperature, heat gain and exergy gain change with increasing the additive nanoparticles into the base-fluid (water), while the pressure loss does not change significantly. The temperature gain increases about 60% when the volume fraction of nanoparticles in the base-fluid reaches 2%. This also helps to improve the natural circulation of working fluid and the GHE may not need a circulating pump to run at low flow rates. It is also shown that the additive MgO nanoparticles is more effective than Al2O3 nanoparticles to improve the GHE performance.
Wind Energy Resource Assessment for Suva, Fiji and Design of a 30 kW Wind Turbine
Authors: Singh Krishneel A. , Kutty Saiyad S. , Khan M. G. M. , Ahmed Mohammed Rafiuddin
Published: January 2022

Fiji needs to invest in renewable energy sources to meet its energy needs to reduce the country’s dependence on imported fossil fuels. For investing in wind energy projects, a detailed assessment of wind energy resource is required. In this work, wind speeds were measured at 34 m and 20 m above ground level at a site in Suva for three years and the daily, monthly, yearly and seasonal averages were estimated. Average turbulence intensities at the two heights were also estimated. The Weibull parameters, average wind speed and the wind power density were estimated by using eleven frequentist methods and a Bayesian technique. These twelve methods were compared against each other for their performance using five goodness of fit test and error measures. The best method was found to be the empirical method of Lysen (EML) which gave a mean wind speed of 5.04 m/s and a wind power density (WPD) of 147.79 W/m2. A horizontal axis wind turbine of 30 kW capacity was designed and optimized using Harp_Opt software which works on a multi-objective genetic algorithm. The blade sections (airfoils) were designed using an in-house multi-objective genetic algorithm code by mathematically parametrized 7th order Bezier curve coupled with XFOIL software. The lift and drag coefficients were interpolated using AirfoilPrep to get the data in the required format as needed by the Harp_Opt GUI. The Weibull parameters from the statistical analysis of the measured data were used to optimize the performance characteristics of the wind turbine. The output power curve shows a cut-in speed of about 2 m/s and a rated wind speed of 10 m/s. The AEP was optimized from around 47.3 MWhr/year to 48.3 MWhr/year after 50th iteration of Harp_Opt.
Second-Life Analysis of Lithium-Ion Battery in a Residential Solar Photovoltaic Grid-Tied System
Authors: Alhadri Muapper , Zakri Waleed , Farhad Siamak
Published: January 2022

The behavior of retired lithium-ion battery (LIB) from its first-life application such as electric vehicles and electric aircraft for its second-life in a solar photovoltaic (PV) grid-tied system for residential applications is studied through mathematical modeling. The rate of capacity-fade and the useful remaining life of the retired- or used-LIB particularly investigated in this paper. The first part of this paper presents the optimal size of a small-scale battery energy storage system (BESS) to store a part of the solar energy for postponing consumption in the near future for a typical home in Akron, Ohio. The LIBs in this study has lithium nickel manganese cobalt oxide (NMC) chemistry. The sizing is determined based on a set of PV panels, power rate of the BESS, and hourly data of temperatures, irradiation and home demand load. Using PVWatts® Calculator from National Renewable Energy Laboratory (NREL), the hourly PV performance data of the PV generation system is obtained. In this study, the home is connected to the grid, but the net energy usage from the grid in one year is zero. The duty-cycle of the PV generation is obtained in order to design a LIB energy storage system using calculations of the PV system hourly energy production. The difference between the residential home demand and PV generation is used to evaluate the excess energy that charges the battery and is sold to the electric grid. In the second part, the retired- or the used-battery degradation rate and its remaining useful second-life in the BESS are estimated using an empirical battery model. This model includes the capacity-fade of the LIB for both first- and second-life applications under different operating and environmental conditions. It is shown that a used-LIB from first-life applications is still suitable to be used for this system. The results show that the investigated used-LIB is capable of being in-service for another 10 years in the PV system for residential application. The results of this paper can potentially reduce the battery cost for electric vehicles and electric aircraft because the retired battery from these applications have still value to serve for another applications such as PV system for residential homes. Since this study is based on mathematical modeling, several assumptions have been made in the model. Although the results of mathematical modeling is very promising, these results should be proved experimentally. The experimental studies is out of the scope of this paper.
An Improved Response Function Based Stochastic Meshless Method for Bending Analysis of Thin Plates
Authors: Aswathy M. , Arun C. O.
Published: January 2022

An improved response function (IRF) based stochastic element free Galerkin method (SEFGM) is proposed for the stochastic bending analysis of laterally loaded thin plates. Young’s modulus is considered as uncertain and its spatial variation is modelled as a homogeneous normal random field. Shape function method is used for random field discretization. In IRF method, the total displacement response is represented as the sum of a deterministic part and a stochastic part. The stochastic part is called as IRF and it is a function of the discretized set of random variables. Stochastic stiffness matrix is approximated using Taylor series expansion. A simplified expression for IRF in terms of stiffness derivatives and random variables is derived from the equilibrium considerations of system of stochastic equations. Direct simulations on the IRF combined with deterministic part of response can give the probabilistic characteristics of response quantities. The response characteristics of the plates obtained using the proposed method are compared with those obtained using Monte Carlo simulation (MCS). An ad-hoc response function (ARF) and second order perturbation (SOP) based SEFGM are also used for comparing the results. Square thin plates with two different boundary conditions are solved as the numerical examples. Kirchhoff-Love assumptions and plane stress conditions are considered. The deterministic EFGM used for bending analysis of plates calculates the out of plane deformations and rotations at various points. The probabilistic characteristics of these quantities are measured using the proposed IRF based SEFGM. A parametric study is conducted to investigate the capability of the proposed method in response moment calculations at various coefficients of variation (CV) and correlation length parameters of input random field. The response moments determined using the proposed method are found to be in good agreement with those obtained using MCS even at a CV of 30%. It is found that the proposed method can calculate the response moments accurately, regardless of the correlation length parameters of the input random field. These are attributed to the fact that the proposed IRF method considers the complete displacement response without any approximation. The probability density function and the cumulative distribution function of response quantities of plates calculated using the proposed method are observed to be comparable with those obtained using MCS. From a study on normalized computational times, the proposed IRF method is found to be computationally more efficient compared to MCS. In the proposed method, the stiffness derivatives and deterministic part of the displacement response are calculated outside the simulation loop. This along with the use of discretized set of random variables inside the simulation loop, calculates the IRF and hence the response statistics, that makes the method computationally more efficient compared to MCS.
Crack Detection and Evaluation Method for Self-Piercing Riveting Button Images Based on BP Neural Network
Authors: Hu Ke , Jiang Ling , Zhan Zhenfei , Wu Fei
Published: January 2022

Self-piercing rivet (SPR), a method used for joining sheet materials, is of increasing interest in the automobile industry. Cracks on the SPR joint surface might affect the joint strength significantly. This paper proposed a novel crack detection and evaluation method for SPR button images based on machine learning, which will address the issue of time-consuming and subjective caused by manual visual crack inspection. Firstly, sub-images are cropped from the button images and preprocessed into three categories (i.e., cracks, edges, and smooth regions) as training samples. At the sub-images level, 5 neural networks are trained with the input of different extracted features, respectively. Then, to overcome the representation limitation of one single extracted feature, a weighted combination of 5 neural networks is developed. Thirdly, a search algorithm is developed to extend the application of the learned model from sub-images into the original button images. Lastly, an evaluation system based on the characteristics of SPR button images is proposed to compare and analyze these different application results. The preliminary results on non-cracked and cracked button images show that the proposed crack detection method of weighted combination is an effective approach, which gets better crack detection results compared to other crack detection models with a single extracted feature of input.
Hydrogen: Fuel of the Future?
Authors: Baukal Charles , Whelan Matt , Londerville Steve , Haag Michel , Theis Gilles , Johnson Bill
Published: January 2022

Hydrogen is a unique fuel in many ways. It has the potential to eliminate both carbon monoxide and carbon dioxide emissions. However, it could increase NOx emissions compared to more conventional fuels. Hydrogen has many unique properties such as a wider flammability range, higher adiabatic flame temperature, higher flame speed, lower heating value on a volume basis, and lower combustion air requirements. Some potential safety concerns include a higher propensity to flash back on pre-mix burners because of the higher flame speed and to leak because H2 is a very small molecule. Because of its many unique properties, there are some important design considerations when retrofitting a combustion system designed to use a conventional fuel like natural gas to use hydrogen. This paper investigates some of the key differences when using hydrogen as a fuel compared to typical hydrocarbons. It considers the impact on: the fuel and air delivery systems, flame detection, burner design, heat transfer, and pollution emissions. It includes two specific examples of implementation in process heaters and a boiler.
Investigations Into the Linear Coupling Between Symmetric and Anti-Symmetric Modes of V-Shaped MEMS Resonators Under Electrostatic Perturbation
Authors: Alcheikh Nouha , Ouakad Hassen M. , Ben Mbarek Sofiane , Younis Mohammad I.
Published: January 2022

In this paper, we investigate experimentally and theoretically the linear coupling between the first two symmetric and anti-symmetric modes of an electrothermally and electrostatically actuated in-plane V-shaped micro-beam. The micro-beam is fabricated from highly doped silicon and is sandwiched between four electrodes to electrostatically activate both modes of vibrations. When tuning the electrothermal voltage, the natural frequencies of the two modes approach each other until they cross. Under electrostatic actuation, it is shown experimentally that the system undergoes a transition between modes crossing to veering. In addition, an analytical study is presented based on a Galerkin-based reduced-order model of a nonlinear Euler–Bernoulli shallow arch beam equation. The analytical results are compared to experimental data showing excellent agreement.