bluuebunny/crossref_metadata_2025 huggingface dataset:
Circular Plates Under Hard Excitations to Include Casimir Effect: Amplitude-Voltage Response of Superharmonic Resonance of Second Order
Authors: Caruntu Dumitru I. , Beatriz Julio , Perez Jonathan
Published: February 2021

This paper deals with voltage-amplitude response of superharmonic resonance of second order of electrostatically actuated clamped MEMS circular plates. A flexible MEMS circular plate, parallel to a ground plate, and under AC voltage, constitute the structure under consideration. Hard excitations due to voltage large enough and AC frequency near one fourth of the natural frequency of the MEMS plate resonator lead the MEMS plate into superharmonic resonance of second order. These excitations produce resonance away from the primary resonance zone. No DC component is included in the voltage applied. The equation of motion of the MEMS plate is solved using two modes of vibration reduced order model (ROM), that is then solved through a continuation and bifurcation analysis using the software package AUTO 07P. This predicts the voltage-amplitude response of the electrostatically actuated MEMS plate. Also, a numerical integration of the system of differential equations using Matlab is used to produce time responses of the system. A typical MEMS silicon circular plate resonator is used to conduct numerical simulations. For this resonator the quantum dynamics effects such as Casimir effect are considered. Also, the Method of Multiple Scales (MMS) is used in this work. All methods show agreement for dimensionless voltage values less than 6. The amplitude increases with the increase of voltage, except around the dimensionless voltage value of 4, where the resonance shows two saddle-node bifurcations and a peak amplitude significantly larger than the amplitudes before and after the dimensionless voltage of 4. A light softening effect is present. The pull-in dimensionless voltage is found to be around 16. The effects of damping and frequency on the voltage response are reported. As the damping increases, the peak amplitude decreases. while the pull-in voltage is not affected. As the frequency increases, the peak amplitude is shifted to lower values and lower voltage values. However, the pull-in voltage and the behavior for large voltage values are not affected.
A Conceptual Prototyping Framework for Integrating Human Factors Early in Product Design
Authors: Ahmed Salman , Demirel H. Onan
Published: February 2021

A knowledge-base that integrates human factor engineering (HFE) principles and prototyping best-practices for the design of human-centered products does not exist. This study fills this gap by proposing a prototyping framework to unify HFE principles and prototyping guidelines along with a prototyping toolbox. The framework is based on the House of Prototype Guidelines (HOPG), which introduces “Prototyping Categories and Dimensions” that are used for understanding the prototyping requirements and identifying the specifications that can be used to build a prototype. Additionally, a prototyping toolbox is introduced to classify tools and technologies to build the proposed prototype. The HOPG and prototyping toolbox are integrated via an MS Excel User-form, which proposes a systematic selection filter based on user input. The overall goal of this framework is to guide the prototyping activities in the right direction before the actual hands-on prototyping activity starts. Additionally, in this study, a cost-benefit analysis tool is proposed to calculate the value of the prototype by measuring the information gained and the resources spent. The cost-benefit analysis helps designers in narrowing down the prototyping options. A prototyping problem taken from the literature is used as a case study to demonstrate the usability and efficacy of the framework.
Flow Dynamics and Heat Transfer of a Stranded Overhead Conductor Cable
Authors: Abdelhady Mohamed , Wood David H.
Published: February 2021

Stranded overhead conductor cables are used to transfer electric power, often over large distances. Conductor geometry, as well as environmental conditions, affect the power carrying capacity. This paper studies the flow dynamics and heat transfer for one stranded conductor geometry in air at Reynolds number of 1,000, determined using dynamic Smagorinsky Large Eddy Simulations. Proper Orthogonal Decomposition was used to identify coherent structures. In comparison to a smooth circular cylinder, the conductor strands noticeably affect the flow dynamics and heat transfer, locally and globally.
Design and Testing of a Physical Therapy Device Controlled With Voice Commands
Authors: Patel Harsh , Chung Wing Kin , Viswanathan Vimal , Zaidi Sohail
Published: February 2021

The world population is aging. Age-related disorders such as stroke and spinal cord injury are increasing rapidly, and such patients often suffer from mobility impairments. Wearable robotic exoskeletons are developed that serve as rehabilitation devices for these patients. An assistive knee brace is a simple wearable exoskeleton which is used to help people with mobility issues. This device provides partial assistance to the user and also helps in providing locomotion. Many exoskeletons are currently available in the market that have different functions and use. It is believed that, to date, no voice-controlled knee brace exists in an orthotic application, and that this project debuts a unique approach. This project presents the design of an assistive bionic knee joint with a motor-based actuator. The new exoskeletal mechanism uses the serial elastic actuator concept and mainly consists of a stepper motor, a ball screw, a set of spur gears, and a set of linear springs. The ball screw provides a linear movement to mimic the stretching and retracting action of a human knee. To create a proof-of-concept of the design, 3D printing is used. A voice recognition system has been developed in-house to control the exoskeleton using very simple voice commands. The motor is controlled using a motor driver and powered using an external power source. The 3D printed prototype with integrated voice-control module is tested for its essential functions. The test setup is loaded on the leg of a mannequin and tested under both no-load and full-load operation. The concept is proven to be successful in providing assistance to the human knee. However, the 3D printed material is observed to be bending, causing disruptions in the device’s operation. The reaction times are expected to be significantly larger compared to the theoretically calculated values.
Experimental Flow Visualization Study of Flow Separation Control With High-Frequency Translational Surface Actuation
Authors: Okoye Kenechukwu , Lai Wing , Yeom Taiho
Published: February 2021

Flow separation causes aircraft to experience an increase in drag degrading their aviation performance. The current study aims to delay flow separation on an airfoil by embedding a high-frequency translational piezoelectric actuator along the surface of the airfoil. The actuators with two actuation surfaces were embedded on the suction surface of an Eppler 862 airfoil model and placed in a low-speed wind tunnel. Consecutive pictures of the flow fields with dry ice fogs around the airfoil were taken using a high speed camera in order to observe the flow separation phenomenon before and after turning on the high-frequency translational surface actuation. The effects of the actuation on the flow separation were observed at various actuation displacements, angles of attack, and free stream velocities. The operating frequency of the surface actuation was 565 Hz. The measured actuation mean-to-peak displacement ranged up to 0.12 mm at the maximum applied voltage of 150 V. The angle of attack of the airfoil varied from 6° to 24°. The chord Reynolds number was increased up to around 262,000. It was confirmed that the actuation had a very strong influence on the flow separation even at a very small displacement of 0.024 mm remaining significantly reduced separation bubble compared to the one before activating the actuators at 4.3 m/s of velocity and 14° of angle of attack. The flow separation was completely suppressed when the actuation displacement reached around 0.082 mm under the same conditions of flow velocity and angle of attack. This implied that the actuation should generate a strong enough momentum relative to the free stream in order to completely suppress the flow separation. In summary, the study confirmed that the employed high-frequency translational surface actuation had the obvious control authority on delaying or suppressing the flow separation over the airfoil depending on the parameters changed.
Distribution of Bacterial Contamination in Partial Penetration Surrogate Ballistic Wounds
Authors: Frybarger Michelle R. , Muci-Küchler Karim H.
Published: February 2021

With the rise in use of IEDs during armed conflicts, there has been an increase in the number of injuries to the extremities. Shrapnel and debris ejected during the explosion become high-speed projectiles capable of penetrating soft tissues, bringing bacterial contamination into the wound. If not properly treated, that contamination could lead to infection. Studies aimed at understanding the distribution of bacterial contamination along the permanent cavity could provide useful information to improve treatment protocols for these types of injuries. In this paper, a lower extremity surrogate model was used to investigate bacterial distribution in partial penetration ballistic wounds. The targets used were ballistic gelatin blocks that had an Escherichia coli-laden filter paper placed on their front face. Spherical projectiles were fired into the targets adjusting their speed to obtain three different partial penetration depths. After each shot, a gelatin strip containing the permanent cavity was extracted and segmented. The permanent cavity was removed from each segment, placed in a test tube with buffer solution, and heated in a water bath to melt the gelatin. Standard microbiology protocols were followed to determine the number of colony forming units (CFUs) in each segment. The bacteria distribution was represented by percent of total CFU in the permanent cavity versus segment number. In addition, bacterial contamination as a function of projectile penetration depth was explored. For the cases considered, most of the bacterial contamination occurred in the segments closer to the projectile entry point.
Thermal Expansion Simulation of Composite Hydrodynamic Thrust Bearings
Authors: Yasko Isaiah , Lutfullaeva Anbara , Fais Collier , Ali Muhammad , Alam Khairul
Published: February 2021

Fixed-geometry hydrodynamic thrust bearings rely on convergent geometry on the bearing face in the direction of relative motion to develop and maintain hydrodynamic pressure. Machining the convergent taper feature onto the bearing using traditional manufacturing processes can prove to be a difficult process due to the small magnitude of taper depth necessary for proper bearing performance. The work presented here investigates three different types of carbon fibers (AS-4/IM7/T-300) in an epoxy (3501-6) matrix for composite lamina formulation in taper-land composite thrust bearings as a means of controlling taper depth via thermal expansion so that favorable bearing functionality is maintained during load fluctuation without the need for traditional machining processes to create the taper. Thermal expansion of specific composite laminate formulation is analyzed using the ABAQUS/CAE composite module. The thermo-mechanical analysis shows that under realistic in-service temperature conditions resulting from bearing friction-torque, the thermal expansion of composite tapered-land thrust bearings expand to provide physical surface gradient magnitudes of 0.09504 mm, 0.08987 mm and 0.08829 mm that are capable of producing hydrodynamic pressure.
Quantum CFD Simulations for Heat Transfer Applications
Authors: Lu Chao , Hu Zhao , Xie Bei , Zhang Ning
Published: February 2021

In this paper, computational heat transfer (CHT) equations were solved using the state-of-art quantum computing (QC) technology. The CHT equations can be discretized into a linear equation set, which can be possibly solved by a QC system. The linear system can be characterized by Ax = b. The A matrix in this linear system is a Hermitian matrix. The linear system is then solved by using the HHL algorithm, which is a quantum algorithm to solve a linear system. The quantum circuit requires an Ancilla qubit, clock qubits, qubits for b and a classical bit to record the result. The process of the HHL algorithm can be described as follows. Firstly, the qubit for b is initialized into the phase as desire. Secondly, the quantum phase estimation (QPE) is used to determine the eigenvalues of A and the eigenvalues are stored in clock qubits. Thirdly, a Rotation gate is used to rotate the inversion of eigenvalues and information is passed to the Ancilla bit to do Pauli Y-rotation operation. Fourthly, revert the whole processes to untangle qubits and measure all of the qubits to output the final results for x. From the existing literature, a few 2 × 2 matrices were successfully solved with QC technology, proving the possibility of QC on linear systems [1]. In this paper, a quantum circuit is designed to solve a CHT problem. A simple 2 by 2 linear equation is modeled for the CHT problem and is solved by using the quantum computing. The result is compared with the analytical result. This result could initiate future studies on determining the quantum phase parameters for more complicated QC linear systems for CHT applications.
Heat Transfer Characteristics of 1-D Ferromagnetic Nanofluid
Authors: Shiave Ali Imran , Mohan Ram
Published: February 2021

Improving the efficiency of the cooling medium to increase productivity and decrease energy consumption is one of the biggest challenges in the current world. Industries, including transportation, manufacturing, and electronic devices, etc. need efficient thermal management and can benefit from the use of efficient cooling media. Industrial coolants i.e. water, ethylene glycol (EG), or mineral oils have long been used for heat transport though the low thermal conductivity (TC) of these coolants has made them inefficient options for high-performance operations. Metal nanofluids can be potential candidates to replace these inefficient coolants because of their superior thermal properties such as high thermal conductivity, diffusivity, and heat transfer coefficient compared to the base fluids. Nanofluids are a stable suspension of nanoparticles in base media which can offer better thermal conductivity and efficiency. However, preparing stable suspension is one of the major challenges of preparing nanofluids as nanoparticles can aggregate faster over time because of their high surface energy which in turn can have an adverse effect on thermal properties. So far, most research investigations have been done on 0-D nanofluids whereas 1-D nanostructure-based nanofluid study is still very limited. In this work, we have developed a suitable route to prepare novel water-based Cobalt nanowire nanofluids and studied their thermal conductivities. Our study shows that the prepared nanofluid is stable and the thermal conductivity is increased by up to 8.5% compared to base fluid (water).
Use of a Trophic Structure Test Bed to Validate a New Systems-of-Systems Resilience Metric
Authors: Watson Bryan C. , Kriplani Sanaya , Weissburg Marc J. , Bras Bert
Published: February 2021

Systems of Systems (SoS) combine complex systems such as financial, transportation, energy, and healthcare systems to provide greater functionality. A failure in a constituent system, however, can render the entire SoS ineffective by causing cascading faults. One method to prevent constituent faults from compromising SoS performance is to increase the SoS’s “resilience,” a measure of the SoS’s ability to cope with these faults and efficiently recover. Attempts to engineer improved resilience require a metric to measure resilience across different SoS architectures (network arrangements). In a previous work, the System of System Resilience Metric (SoSRM) was presented as a possible solution, but this new metric requires additional testing. This work examines the key question: “How can natural ecosystem characteristics be used to validate the SoSRM metric?” We hypothesize that the analysis of a test bed of generic ecosystems will produce SoSRM values that will positively correlate with a triangular trophic structure (wide base), validating SoSRM as a useful design metric. First principles for test bed creation are presented including biodiversity, trophic structure, and the role of detritus. SoSRM is measured for 31 case studies in a trophic structure test bed. Ecosystem network structure is quantified with graph theory. SoSRM correlates as expected with ecosystem network structure (r2 = .5016, n = 31), thus providing a validation of SoSRM as a design tool. As a final check, tests are conducted to ensure SoSRM is independent of trivial network characteristics (i.e. the number of nodes or links). By validating SoSRM, we provide a foundation for future work that focuses on increasing SoS resilience with biologically inspired design heuristics.
Modelling and Control of a Translational Robotic Arm
Authors: Wei Bin
Published: February 2021

The objective of this paper is to design and model a translational robotic arm that is simple and cheap to manufacture while maintaining good functionality. Once the robotic arm is designed, the control analysis and computer simulation are conducted. When selecting the material used for the parts, the density and strength of are considered. This paper covers the design process, analysis and computer simulation of a robotic arm. The final design is a 4-DOF (degrees of freedom) pick and place robot. This robot has 1 prismatic joint and 3 revolute joints. The arm is designed to be used in multiple applications such as pick and place, car wash, chalkboard erasers, etc. Forward kinematics is used to calculate the end effectors position and orientation based on the positions of each joint. The Lagrange general method is used to come up with the equation of motion. Also, the control method selected for this robot was nonlinear decoupling PD control.
An Innovative Thermal Analysis Model for Continuous Operation of a Solar Collector
Authors: Nokhosteen Arman , Sobhansarbandi Sarvenaz
Published: February 2021

Heat pipe evacuated tube solar collectors (HPETCs) are a type of solar collectors widely used in solar water heating (SWH) technologies. In order to optimize the design of SWHs, understanding the heat transfer phenomena in HPETCs is of paramount importance. The complexity of the heat transfer processes involved in modelling a collector’s performance render direct numerical simulations (DNS) computationally cumbersome. In this work, a novel hybrid numerical method is employed in order to simulate the thermal behaviour of HPETCs, both during day and night time operation. This method is comprised of a previously developed resistance network based proper orthogonal decomposition (RNPOD) method for simulation during operation hours were solar irradiation values are greater than zero; after which, an in-house code based on Lattice Boltzmann method (LBM) has been utilized for simulation when irradiance is zero. This hybrid method is able to reduce simulation time and take into account the ambient working conditions of the collector and therefore, provide an accurate assessment of the temperature distribution inside the collector during the entirety of its operation during a full working cycle. The obtained results of this study are cross-validated with the previous experimental work of the authors, illustrating that the model is able to predict the peripheral temperature distribution with an average error of less than 10%.
Numerical Analysis of Optimal Design Parameters for a Cell Co-Culture Microfluidic Platform With an Integrated Pressure-Controlled Valve
Authors: Ishraq Bari Saif Mohammad , Reis Louis G. , Holland Thomas , Nestorova Gergana G.
Published: February 2021

This study reports the design, fabrication, and a two-dimensional numerical analysis to identify the optimal operating parameters of a novel microfluidic co-culture platform with an integrated pressure-controlled valve. Replica molding using 3D printed PDMS molds were used for the fabrication of the individual components of the device. Alternation of the position of the PDMS hydraulic valve permits individual manipulation of the cellular microenvironment of the two adjacent cell culture chambers (27.5 mm × 35 mm × 10 mm). The mathematical model analyzes the deflection profile of the valve in the vertical direction as a function of several parameters: valve thicknesses, the pressure exerted by the fluid inside the pressure chamber, and PDMS elasticity determined by the ratio of the elastomer base and the curing reagent. The valve understudy requires a deflection of 0.5 mm to completely isolate the two cell chambers. The combination of the optimal design parameters is identified using numerical analysis. Mathematical simulations show that the deflection of the membrane is inversely proportional to the valve membrane thickness and directly proportional to the pressure exerted by the fluid on the valve.
Implications of Statistical Spread to Experimental Analysis in a Novel Miniature Kolsky Bar
Authors: Hannah Thomas , Kraft Reuben H. , Martin Valerie , Ellis Stephen
Published: February 2021

Kolsky Bar systems are subjected to inherent system error as all measurement devices are. This is especially true in that as the bar diameter decreases, the system becomes more sensitive to errors such as friction and misalignment. In this work we present a technique for identifying and quantifying the error of a Kolsky system. We also present a method of generating statistically significant bounds for Kolsky systems so that anomalous or improperly executed experiments can be quantitatively identified. This method does not rely on the intuition of the experimentalist to identify an anomalous experiment. After presenting our method for error identification, a series of tests are performed on 2024Aluminum alloy samples. A method is then presented where the system error, as well as some error contributed by a variance in sample dimension, are removed from the calculated error related to the stress on the samples. The result shows the effective variance of the sample response is quite high in the elastic loading period, but reduces when plasticity dominates. This is attributed to the presence of high frequency content in the travelling elastic waves which cannot be accurately measured currently, but is effectively damped out when plastic deformation dominates.
Numerical Investigation of High-Speed Oxy-Fuel Pulsed Detonation for Direct Power Extraction
Authors: Karra Shashank K. , Apte Sourabh V.
Published: February 2021

Oxy-fuel based pulse detonation system can be used for direct power extraction when combined with magnetohydrodynamics (MHD). A space-time conservation element solution element (CE/SE) method is used to investigate the operational envelope of oxy-coal detonations with gaseous methane as a surrogate fuel. The CE/SE method results in a consistent multidimensional formulation for structured/unstructured meshes by providing flux conservation in space and time without the need for complex Riemann solvers to capture solution discontinuities. A modified revised Jones-Lindstedt (JL-R) reaction mechanism accounting for radicals such as O, OH, and H was used as a reduced mechanism to simulate detonation waves from CH4−O2 combustion. The numerical scheme is first verified by comparing predictions with the ZND theory and other published data to show excellent agreement. For shock-induced detonation, the effect of driver shock temperature, pressure, stoichiometric ratio (ϕ) and initial driver shock length, on detonation initiation and propagation was investigated. The simulations accurately predicted detonation velocities, at various ϕ values, compared with available experimental data. The results show that higher gas temperatures and velocities are achieved through oxy-detonations compared to air. The chosen reduced chemical kinetic mechanism, that accounts for radical disassociation, is found to be critical in appropriately limiting heat release during oxy-combustion, thereby predicting detonation temperature and velocity accurately.
Lessons From the Conversion of a Heavy-Duty Compression Ignition Engine to Natural Gas Spark Ignition Operation
Authors: Liu Jinlong , Ulishney Christopher , Dumitrescu Cosmin E.
Published: February 2021

Partial conversion of the large inventory of compression-ignition engines to natural-gas (NG) spark-ignition lean-burn operation can reduce U.S. dependence on imported petroleum and enhance national energy security. This paper describes some of the observations made during such an engine conversion and proposes some solutions to alleviate some of the potential issues. The engine conversion in this study consisted from replacing the diesel injector with a spark plug and adding a port fuel injection system for NG delivery. The results indicated that the retrofitted engine performed reliably at lean-burn conditions, despite the different combustion characteristics compared to conventional SI engines. However, the squish region will trap an important fuel fraction (∼30%) and experience less-optimal burning conditions, hence a slower burning rate. This affected the engine efficiency and increased the unburned hydrocarbon and carbon monoxide emissions. From a combustion point of view, the operation of such converted engines can be optimized by increasing the bowl-to-squish volume ratio, optimizing the piston shape (e.g., by removing the central protrusion and avoiding 90-degree edges inside the bowl). The original compression ratio may also need to be reduced to avoid knocking. Moreover, direct gas injection and/or intake charging will increase the volumetric efficiency, which will benefit engine efficiency and emissions.
An Efficient Galerkin Averaging-Incremental Harmonic Balance Method Based on the Fast Fourier Transform and Tensor Contraction
Authors: Ju R. , Fan W. , Zhu W. D.
Published: February 2021

An efficient Galerkin averaging-incremental harmonic balance (EGA-IHB) method is developed based on the fast Fourier transform (FFT) and tensor contraction to increase efficiency and robustness of the IHB method when calculating periodic responses of complex nonlinear systems with non-polynomial nonlinearities. As a semi-analytical method, derivation of formulae and programming are significantly simplified in the EGA-IHB method. The residual vector and Jacobian matrix corresponding to nonlinear terms in the EGA-IHB method are expressed using truncated Fourier series. After calculating Fourier coefficient vectors using the FFT, tensor contraction is used to calculate the Jacobian matrix, which can significantly improve numerical efficiency. Since inaccurate results may be obtained from discrete Fourier transform-based methods when aliasing occurs, the minimal non-aliasing sampling rate is determined for the EGA-IHB method. Performances of the EGA-IHB method are analyzed using several benchmark examples; its accuracy, efficiency, convergence, and robustness are analyzed and compared with several widely used semi-analytical methods. The EGA-IHB method has high efficiency and good robustness for both polynomial and nonpolynomial nonlinearities, and it has considerable advantages over the other methods.
Influence of Complexity, Innovation, Newness and Learning on Project Success in New Development Projects: A Study in Manufacturing Industry
Authors: Beste Carina , Welo Torgeir , Olsson Nils O. E.
Published: February 2021

In the execution of product development projects, deviation in time, budget and quality must be avoided. The expectations on these outcomes are high, especially in commodity-type projects, where most of the project content is assumed known upfront. On the other hand, increasingly complex project environments face constantly changes, where shift in scope is more the rule than the exception. In this study, we cluster factors assumed pushing the project boundaries of exploration in terms of innovation, complexity and newness. We pose an initial hypothesis that dealing with unplanned changes, or ‘newness’, has an overall negative outcome on project outcomes, despite the underlying intentions. It is also hypothesized that learning capabilities of the product development team is a major factor for successfully dealing with the dynamics of newness. To test both hypothesizes, we first developed and executed a survey involving 10 manufacturing companies. The participants were asked to rate 25 statements related to innovation, complexity and newness, and their perceived impact on overall project success. The results show a clearly negative correlation between successful projects and newness. To test the second hypothesis, the single statements for ‘newness’ was divided into positive and negative learning. The term ‘negative learning’ is used when stress occurs and therefore knowledge and abilities are not properly developed. Positive learning describes on the other hand if motivation is high and active learning occurs. The results show that newness statements related to positive learning has a positive impact on project outcomes, whereas negative learning has a negative impact on project success.
Entropy-Based Optimization of Helical Fins for Heat Transfer Enhancement Inside Tubes
Authors: Pidaparthi Bharath , Li Peiwen , Missoum Samy
Published: February 2021

The design optimization of a tube with internal helical fins is considered from an entropy generation point of view. The primary focus of the article is to study the optimization results based on entropy-based formulations. Specifically, this work compares the optimal design solution obtained through the minimization of total entropy and through the multiobjective optimization of the heat transfer and frictional entropies when considered as two separate objectives. The latter quantities being associated with heat transfer and pressure drops, it is shown that, from a design optimization point of view, it is important to separate both entropies which are conflicting objectives.
Digital Twin for Smart Manufacturing: The Practitioner’s Perspective
Authors: Bärring Maja , Johansson Björn , Shao Goudong
Published: February 2021

The manufacturing sector is experiencing a technological paradigm shift, where new information technology (IT) concepts can help digitize product design, production systems, and manufacturing processes. One of such concepts is Digital Twin and researchers have made some advancement on both its conceptual development and technological implementations. However, in practice, there are many different definitions of the digital-twin concept. These different definitions have created a lot of confusion for practitioners, especially small- and medium-sized enterprises (SMEs). Therefore, the adoption and implementation of the digital-twin concept in manufacturing have been difficult and slow. In this paper, we report our findings from a survey of companies (both large and small) regarding their understanding and acceptance of the digital-twin concept. Five supply-chain companies from discrete manufacturing and one trade organization representing suppliers in the automotive business were interviewed. Their operations have been studied to understand their current digital maturity levels and articulate their needs for digital solutions to stay competitive. This paper presents the results of the research including the viewpoints of these companies in terms of opportunities and challenges for implementing digital twins.
Conversion From Traditional Manufacturing to Digital Manufacturing, an Industry 4.0 Application in Furniture Making
Authors: Xiao Angran , Chen Mason , Gailani Gaffar , Zhang Andy
Published: February 2021

The concept of Industry 4.0 was presented to upgrade the manufacturing systems of large enterprises or even countries. Although some implementation paradigms and frameworks for implementation have been developed, only a minute selection suit the special needs and characteristics of small to medium enterprises (SME’s). On the other hand, SME’s account for a significant market share of the economy, and are in great needs to modernize and diversity their manufacturing capabilities in order to remain competitive in today’s marketplace. In this paper, we present a framework for implementing Industry 4.0 in SME’s. As a work in progress, the product customization and manufacturing sections of the aforementioned framework are being implemented, which are being utilized by a local furniture maker for a custom order of wooden bookcases.
Multi-Scale Fatigue Modeling and Design Optimization of Bottom Hole Assemblies in High-DLS Applications
Authors: Li Ke , Karuppoor Srinand , Ossia Sepand
Published: February 2021

To quantify the fatigue strength of bottom hole assembly (BHA) components used in high-bending drilling conditions, a multi-scale approach for fatigue analysis of BHAs was developed, which entails calculations at the BHA scale, the component scale, and the feature scale. At the BHA level, a beam-type model was constructed, with the BHA information and drilling parameters as the input. The calculated shear force, contact force, and bending moment were then used as the loading conditions for the finite element models at the component level, which involves drill collars and threaded connections. A local strain based fatigue damage criterion was thereafter employed to compute the fatigue life at the critical features. Part of the outcome from this multi-scale model is a relation between bending moment and fatigue life, which is inherent for each collar or each connection. This relation can then be used to design a BHA, track the fatigue damage of a BHA during operation, and perform root cause analyses if a fatigue related failure has taken place. The methodology was validated with lab experiments and field practices.
Determination of the Thermal Properties of a PCB by Coupled Numerical and Experimental Approach
Authors: Usul Yener , Özçatalbaş Mustafa
Published: February 2021

Increasing demand for usage of electronics intensely in narrow enclosures necessitates accurate thermal analyses to be performed. Conduction based FEM (Finite Element Method) is a common and practical way to examine the thermal behavior of an electronic system. First step to perform a numerical analysis for any system is to set up the correct analysis model. In this paper, a method for obtaining the coefficient of thermal conductivity and specific heat capacity of a PCB which has generally a complex composite layup structure composed of conductive layers, and dielectric layers. In the study, above mentioned properties are obtained performing a simple nondestructive experiment and a numerical analysis. In the method, a small portion of PCB is sandwiched from one side at certain pressure by jaws. A couple of linear temperature profiles are applied to the jaws successively. Unknown values are tuned in the analysis model until the results of FEM analysis and experiment match. The values for the coefficient of thermal conductivity and specific heat capacity which the experiment and numerical analysis results match can be said to be the actual values. From this point on, the PCB whose thermal properties are determined can be analyzed numerically for any desired geometry and boundary condition.
A Novel Training Bike and Camera System to Evaluate Pose of Cyclists
Authors: Garimella Raman , Beyers Koen , Peeters Thomas , Verwulgen Stijn , Sels Seppe , Huysmans Toon
Published: February 2021

Aerodynamic drag force can account for up to 90% of the opposing force experienced by a cyclist. Therefore, aerodynamic testing and efficiency is a priority in cycling. An inexpensive method to optimize performance is required. In this study, we evaluate a novel indoor setup as a tool for aerodynamic pose training. The setup consists of a bike, indoor home trainer, camera, and wearable inertial motion sensors. A camera calculates frontal area of the cyclist and the trainer varies resistance to the cyclist by using this as an input. To guide a cyclist to assume an optimal pose, joint angles of the body are an objective metric. To track joint angles, two methods were evaluated: optical (RGB camera for the two-dimensional angles in sagittal plane of 6 joints), and inertial sensors (wearable sensors for three-dimensional angles of 13 joints). One (1) male amateur cyclist was instructed to recreate certain static and dynamic poses on the bike. The inertial sensors provide excellent results (absolute error = 0.28°) for knee joint. Based on linear regression analysis, frontal area can be best predicted (correlation > 0.4) by chest anterior/posterior tilt, pelvis left/right rotation, neck flexion/extension, chest left/right rotation, and chest left/right lateral tilt (p < 0.01).
A New Dynamic Model of a Two-Wheeled Two-Flexible-Beam Inverted Pendulum Robot
Authors: Mehrvarz Amin , Khodaei Mohammad Javad , Clark William , Jalili Nader
Published: February 2021

Inverted pendulums are traditional dynamic problems. If an inverted pendulum is used in a moving cart, a new type of exciting issues will appear. One of these problems is two-wheeled inverted pendulum systems. Because of their small size, high performance in quick driving, and their stability with controller, researchers and engineers are interested in them. In this paper, a new configuration of one specific robot is modeled, and its dynamic behavior is analyzed. The proposed model can move in two directions, and with a proper controller can keep its stability during the operation. In this robot, two cantilever beams are on the two-wheeled base, and they are excited by voltages to the attached piezoelectric actuators. The mathematical model of this system is obtained using the extended Hamilton’s Principle. The results show that the governing equations of motion are highly nonlinear and contain several coupled partial differential equations (PDEs). In order to extract the natural modes of the beams, the undamped, unforced equations of motion and boundary conditions of the beams are used. If a limited number of modes (N1 and N2) are selected for each beam, the coupled PDEs will be changed to N1 + N2 + 5 ordinary differential equations (ODEs). These complex equations are solved numerically, and the natural frequencies of the system are extracted. The system is then simulated in both lateral and horizontal plane movements. The simulation shows that the governing equations are correct, and the system is ready for designing a proper controller. It should be mentioned that in the future works, the derived equations will be validated experimentally, and a suitable control strategy will be applied to the system to make it automated and more applicable.
Influence of Process Parameters on the Microstructure, and Geometrical Characteristics of Laser Additive Manufactured (LAM) Titanium Alloy Composite Coatings
Authors: Fatoba O. S. , Lasisi A. M. , Akinlabi S. A. , Akinlabi E. T. , Adediran A. A.
Published: February 2021

The study experimentally investigates the effects of Ytterbium Laser System process parameters on the resultant microstructure of Ti-6Al-4V grade 5 alloy and reinforcement powders. The deposition process was conducted employing a 3 kW (CW) Ytterbium Laser System (YLS-2000-TR) machine, coaxial to the reinforcement powder. The laser scanning speed and power were varied between the intervals of 0.8–1.0 m/min and 900–1000 W. All other parameters kept constant were the rate of gas flow, the spot diameter, and the rate of powder flow. Metallurgical studies were conducted where all the samples microstructure was characterized by employing Scanning Electron Microscopy (SEM) and Optical Microscopy (OM). The results showed that a minimum porosity was achieved at high laser power complemented with low powder feed rate. The microstructure formed was dominated by columnar grains and martensitic needle-like structures with a formation of beta phase. It was observed that the microstructure was influenced significantly by the two laser speed modes, and the laser power. The grain size and phase structure were influenced significantly by the laser power; increasing it had resulted in larger grains, and a coarser microstructure. The results also showed that the residual stresses of the optimized specimens were compressive.
Investigation of Gravity Effects on Electrically Driven Liquid Film Flow Boiling: A Micro-Gravity Flight Campaign in Preparation of ISS Experiment
Authors: Castaneda Alexander J. , O’Connor Nathaniel J. , Yagoobi Jamal
Published: February 2021

The ongoing development of modern electronic systems leads to smaller, more powerful devices that are expected to operate in complex environments. Due to this, advanced thermal management technologies are required to meet the growing demand, especially in space where two-phase thermal systems are limited by the absence of gravity. Electrohydrodynamic (EHD) and dielectrophoretic (DEP) forces can be used to sustain stable liquid film boiling in micro-gravity, which is otherwise impractical due to the lack of a required buoyancy force to initiate bubble departure. EHD and DEP are phenomena that are represented by the interaction between electric fields and fluid flow. The DEP force especially is characterized by the unique ability to act on liquid/vapor interfaces due to a high gradient of electrical permittivity, allowing for two phase operation. This study investigates the effect of EHD conduction pumping coupled with DEP vapor extraction on liquid film flow boiling during a microgravity parabolic flight, and it characterizes the future two-phase microgravity heat transport technology prior to testing on the International Space Station (ISS). The results of this study show that EHD and DEP raise critical heat flux, lower heater surface temperature, and successfully sustain boiling in micro-gravity all at the cost of low power consumption. Additionally, the heat transfer data captured in terrestrial, microgravity, and 1.8 g conditions compare well, indicating that this technology can provide thermal enhancement independent of gravity. This study paves the way for future implementation of EHD-driven two-phase heat transport devices into space and aeronautical electronics applications.
Nonlinear Control Design for a Gravity Compensation Mechanism for Human Lower Limb Rehabilitation
Authors: Ilhan Zeki Okan , Chew Meng-Sang
Published: February 2021

Dynamics of a two degree-of-freedom suspension mechanism is incorporated into nonlinear control design to facilitate its potential use as a rehabilitation device to aid people with lower-limb injuries. The proposed mechanism is a variation of the standard four-bar linkage with an extra link and two springs. The system dynamic model is first extracted based on the Lagrange’s equations in conservative form. The performance deviations due to the link inertia is demonstrated in open-loop numerical simulations under an impulsive force scenario. Finally, the dynamic model of the suspension mechanism is incorporated into feedback control design based on nonlinear, sliding mode control strategy that can add robustness against modeling uncertainties and external disturbances. The tracking performance of the proposed nonlinear controller is validated in closed-loop numerical simulations to demonstrate possible performance improvements under feedback control.
Thermal Management of a Reversible Solid Oxide System for Long-Term Renewable Energy Storage
Authors: Mottaghizadeh Pegah , Fardadi Mahshid , Jabbari Faryar , Brouwer Jack
Published: February 2021

In this study, an islanded microgrid system is proposed that integrates identical stacks of solid oxide fuel cell and electrolyzer to achieve a thermally self-sustained energy storage system. Thermal management of the SOEC is achieved by use of heat from the SOFC with a heat exchanger network and control strategies. While the SOFC meets the building electricity demand and heat from its electrochemical reactions is transferred to the SOEC for endothermic heat and standby demands. Each component is physically modelled in Simulink and ultimately integrated at the system level for dynamic analyses. The current work simulates a system comprised of a wind farm in Palm Springs, CA coupled with the SOEC (for H2 generation), and an industrial building powered by the SOFC. Results from two-weeks of operation using measured building and wind data showed that despite fluctuating power profiles, average temperature and local temperature gradients of both the SOEC and SOFC were within desired tolerances. However, for severe conditions of wind power deficit, H2 had to be supplied from previous windy days’ storage or imported.
Experimental Investigation of the Settling of Carbon-Based Nanoparticles in Renewable Jet Fuel
Authors: Hentges Nicholas , Singh Gurjap , Ratner Albert
Published: February 2021

Recent studies have shown that the addition of nanomaterials to fuels can improve combustion characteristics. A downside, however, is that these mixtures are unstable and prone to phase separation. Finding stable nanomaterial-fuel mixtures are required to make these mixtures viable for practical use. Current research studied the stability of Renewable jet fuel combined with multiple nanomaterial additives being acetylene black, graphene nanoparticles, and multiwalled carbon nanotubes, at 1.0% w/w ratio. Results were compared with prior research and it was shown that renewable jet fuel had a similar effect on settling as soy biodiesel and the results indicated that the fuel’s bulk viscosity was not a major factor determining the stability of the nanofuel.
Arm Movement Analysis in Human Daily Life for Improving Durability of Artificial Elbow Joint
Authors: Kamio Chihiro , Aihara Tatsuhito , Minorikawa Gaku
Published: February 2021

Human movement data can contribute to the quality improvement of industrial and medical products affected by such movement. Such data can be used to improve the quality of industrial products as well as in healthcare applications, such as the development of artificial joints. To develop and design artificial joints with enhance durability, it is necessary to set up standards of durability using human movement data in daily life. The aim of this study is to obtain data that contributes to the improvement in durability of artificial elbow joints. We have developed a wearable device that can measure its self-acceleration, angular velocity, and quaternions to collect human movement data continuously for long-term. Additionally, we collected the arm movement data of 30 participants using the developed device. The participants of this study carried on with their normal lives with the measuring device worn on their wrist. This study calculated the posture of the wrist over time using quaternions and mainly analyzed posture changes. We clarified the characteristics and trends of the movement of bending the elbow in daily human life.