bluuebunny/crossref_metadata_2025 huggingface dataset:
A Comprehensive Analysis of an Electrolytic Hydrogen Production System Based on Solar Radiation for the Generation of Clean Energy
Authors: Mas Ronald , Antoniou Antonios , Celis Cesar , Berastain Arturo
Published: January 2022

A comprehensive analysis of electrolytic hydrogen production systems based on solar radiation is carried in this work. In the referred analysis, directly coupled photovoltaic-electrolyzer hydrogen production systems were studied. Specifically, the studied systems were split into three subsystems, (i) photovoltaic (PV) power production, (ii) electrolyzer based hydrogen production, and (iii) hydrogen storage in tanks, each of them having its own model considerations and restrictions. Detailed mathematical models for the referred subsystems, including different photovoltaic and electrolyzer related technologies, have been developed and utilized in the analyses performed here. In particular, employing the aforementioned mathematical models, a modeling and simulation platform has been developed. Once developed, such platform has been used to parametrically study the behavior of entire hydrogen production systems, accounting for key variables such as solar irradiance, photovoltaic modules and electrolyzer cells temperature, and hydrogen production rate. Several plant designs options have been firstly determined and from the obtained results a specific one has been selected to further assessments. The particular system studied here is currently in the design phase so the outcomes from this work will be used in future for not only properly sizing it but also building and testing it. It is expected that the implementation of large-scale green hydrogen production plants will reduce the impact of energy production systems on both health and environment.
Flow Disturbance Generators Based on Oscillating Cylinders With Attached Splitter Plates
Authors: Hughes Michael , Mook Mariah , Jenkins Michael , SureshBabu Arun Vishnu , Gopalarathnam Ashok , Bryant Matthew
Published: January 2022

The interaction between upstream flow disturbance generators and downstream aeroelastic structures has been the focus of several recent studies at North Carolina State University. Building on this work, which observed the modulation of limit cycle oscillations (LCOs) in the presence of vortex wakes, this study examines the design and validation of a novel disturbance generator consisting of an oscillating cylinder with an attached splitter plate. Analytical design of the bluff body was performed based on specific flow conditions which produced LCO annihilation in previous studies. Computational fluid dynamics simulations and experimental wind tunnel tests were used to validate the ability of the new disturbance generator to produce the desired wake region. Future work will see the implementation of this novel design in conjunction with aeroelastic structures in an effort to modulate and control LCOs, including the excitation and annihilation thereof.
A Comparison of Visco-Hypoelastic and Visco-Hyperelastic Model to Predict the Elastic Strain Energy for Articular Cartilage of Knee Joint
Authors: González-Navarrete Roberto , Vidal-Lesso Agustín , Plascencia Mora Héctor , Huerta-Jacobo Xavier Ulises
Published: January 2022

The aim of this work is to propose a viscoelastic material model for human cartilage tissue that allows simulating its structural stiffness and elastic strain energy that absorbs per unit volume.

For this, experimental data reported from flat cylindrical indentation test on human samples of seven patients with unicompartmental osteoarthritis (N = 7) were used. These data allowed the use of one linear model and the adjustment of two non-linear material models, a visco-hypoelastic (VE) and a visco-hyperelastic (VHE) model. The finite element models for the indentation test considered the indenter as a rigid body, the cartilage and subchondral bone as deformable bodies. The indentation force (F, material model structural reaction) and resilience modulus (Er, elastic strain energy per unit volume) were considered as validation parameters.

The results suggest that largest differences respect to experimental data were found with the linear model (up to 44.33% for Er and 21.75% for F). The best model to reproduce the indentation force was the VHE (mean difference of 3.37±1.03%), while for the elastic strain energy per unit volume, the best model was the VE (mean difference of 16.65±12.74%).
Digital Thread Approach for Smart-Collaborative Robotic Cell
Authors: García Martínez Rubén Febronio , Urbina Coronado Pedro Daniel , Valdivia Puga José Abraham , Ahuett Garza Horacio , Orta Castañon Pedro Antonio
Published: January 2022

Smart Manufacturing advances have recently emerged, focused on the integration of Digital Thread (DTh) and Digital Twin (DT). DTh-DT has been explored in additive manufacturing, aircraft production, and weapons. However, there is still an area of opportunity to explore DTh-DT in collaborative manufacturing cells, layouts, and specifically, in the creation of a system to make an intelligent robotic cell.

This work provides a novel approach of a DTh-DT developed to function within a manufacturing robotic cell. A discrete event simulation (DES) was created with open-source programming software, representing the cell. Information is collected from the physical process and sent to a cloud service. The DES request the data from the cloud is executed and the results are received by a database, which works with a Server (Ignition 8.0). The Server receives data and displays results, working as the link between the DT and the Product Lifecycle. This work presents a quick look at a DTh applied to a robotic cell, an approach to a DT, and the use of different types of communications and platforms. The potential benefits of applying this type of configuration in an Industry 4.0 environment are described and critically reviewed.
Mechanical Properties and Durometer Testing Relationship of Thermoplastic Polyurethane
Authors: Romero-Ramirez Edwar , Clarke Charisma , Siddiqui Sanna F. , Carbajal Gerardo
Published: January 2022

In this paper, the effect of various additive manufacturing processing parameters on thermoplastic polyurethane’s mechanical properties and the durometer hardness testing were evaluated. Additive manufacturing of thermoplastics is a rapidly growing field in many areas, from hobbyists to manufacturing industries. Parts are built layer by layer following the slicing software settings that convert a 3D object into a group of 2D regions that resembles CNC code. There is a need to understand how the mechanical properties are affected by the process parameters compared to traditional injection molding manufacturing. This thermoplastic has use in many automotive industry applications and consumer products because of its elasticity and high abrasion resistance. A generic thermoplastic polyurethane, also known as flexible TPU, with Shore A durometer hardness of 95 was used for this task. It was found that the number of solid layers impacts the mechanical properties higher than other printing parameters. Maximum tensile strength of up to 51.4±6.0 MPa for 84.1±3.8 Shore A durometer hardness was measured.
Aerodynamic Performance Analysis of Winglets of Modern Sailplanes
Authors: Kästner Jens , Epple Philipp , Steppert Michael
Published: January 2022

In this work the aerodynamic performance of winglets of modern sailplanes were investigated. First isolated wings with winglets were designed and investigated and compared to the wings without winglets, showing the fundamental working principle and effectiveness of winglets. Then a complete sailplane was designed with an integrated inviscid flow method with XFLR5 [1] combined with Navier-Stokes CFD with Siemens PLM STAR CCM+ computations. In such a way a modern sailplane was designed for operation with winglets. Using this modern sailplane design the impact of winglets on sailplanes was investigated in detail. This modern sailplane was simulated with CFD in the configurations without winglets and with two modern advanced winglets and their aerodynamic characteristics and performance were investigated and compared. All aerodynamic results are analyzed and shown in detail.
Behavior of Cell Flowing Over Oblique Micro Rectangular Groove
Authors: Hashimoto Shigehiro , Yonezawa Hiroki , Uehara Shogo
Published: January 2022

Is it possible to distinguish cells with minimally-invasive method according to the characteristics of cells when moving through the flow path in vitro? A microflow channel with 45 degrees diagonal microgrooves against the mainstream direction has been manufactured by photolithography technique. The flow path between the two transparent PDMS (polydimethylsiloxane) disks (0.05 mm high, 1 mm wide, and 25 mm long) has a rectangular microgroove (4.5 μm deep, 0.2 mm long) at the bottom with variations in groove widths (0.03 mm, 0.04 mm, and 0.05 mm). The deformation and direction change of floating mouse-myoblasts (C2C12) during passage over the microgroove were measured. The experimental result shows that the change in angle tends to be smaller for cells with larger shape changes in the groove. This method may be applicable to classification by cell deformability.
Effect of Single and Multiple Protuberances on the Aerodynamic Performance of a Wind Turbine Blade
Authors: Bapat Archit , Salunkhe Pramod , Varpe Mahesh
Published: January 2022

Wind energy currently contributes to nearly 5% of our global electricity production and plays a vital role amongst other renewable energy resources. This work aims to numerically investigate the aerodynamic performance of a NACA 634-021 blade with single and multiple spanwise leading-edge protuberances. Different configurations of protuberances viz. continuous and equally spaced intermittent profiles are evaluated for aerodynamic performance. The numerical simulations showed that stall onset is preponed by the protuberance, however, the performance is improved in the post-stall regime. At 27° angle of attack, the continuous protuberances led to the performance improvement of 44%, whereas intermittent protuberances enhanced the blade performance by 37%. Negligible improvement was observed with a single protuberance. Subsequent studies demonstrated that the formation of counter-rotating vortex pair and their interaction with the retarding boundary layer imparts much-needed momentum and plays a significant role in controlling the stall inception. At higher post-stall angle of attack, the continuous protuberances supersede all other cases.
Measurement of Residual Stresses in Laser 3D Printed Train Rail using X-Ray Diffraction Technique
Authors: Mortazavian Ershad , Wang Zhiyong , Teng Hualiang
Published: January 2022

Repairing worn steels using laser powder deposition (LPD) is the focal point of most of the recent studies. The LPD process resides large, anisotropic stresses, which adversely affects the fatigue life. This study investigated residual stresses in a 136RE rail that is repaired via LPD. Residual stresses were measured using X-ray diffraction (XRD). The spikes on the repaired rail sample were discovered using a stylus profiler, and showed peak heights higher than the X-ray penetration depth. This resulted in measuring low stresses due to the interruptions to X-ray beam by the spikes. The sample was polished to eliminate those spikes. However, XRD stress measurement then showed higher stresses than expected, because of the induced stresses on the surface during polishing. Hence, the surface materials were removed by etching to release those stresses. The etched sample was used to measure stress distribution in the repaired rail. The highest tensile values were found at the first and last deposition layers. Comparing the measured stresses (∼250–300 MPa) against the deposition material yield strength (∼215 MPa) indicates a great risk of early cracking. Preheating and post-heating were suggested as viable techniques to reduce the undesirable tensile stresses.
3D-Printed Laboratory Equipment for Vibrations and Control Theory Courses: Pendulum, Cantilever Beam, and Rectilinear System
Authors: Garcia Martin , Estrada Benji , Lucier Elizabeth , Tekes Coskun , Utschig Tris , Tekes Ayse
Published: January 2022

Learning by doing has proven to have numerous advantages over traditionally taught courses in which the instructor teaches the topic while students remain passive learners with little engagement. Although laboratories give hands-on opportunities for undergraduate mechanical engineering students, they have to wait for a semester for the lab course for instance the prerequisite of the vibrations and control laboratory is the mechanical vibrations course. Since the nature of the dynamics branch consisted of dynamics, vibrations, and control theory courses are highly mathematical, students struggle comprehending the introduced topic and relate the theory to its real-world application area. Furthermore, it’s almost impossible for an instructor to bring the existing educational laboratory equipment to the class since they are bulky and heavy. The advents in manufacturing technology such as additive manufacturing bring us more opportunities to build complex systems new materials.

This study presents the design, development, and implementation of low-cost, 3D printed vibratory mechanisms to be utilized in mechanical vibrations, control theory courses along with their associated laboratories. A pendulum, cantilever beam integrated with springs, and a rectilinear system consisted of two sliding carts, translational springs, and a scotch yoke mechanism are designed. The main parts of the mechanisms are 3D printed using polylactic acid (PLA), polyethylene terephthalate glycol (PETG), and thermoplastic polyurethane (TPU).
Design and Development of a Novel Soft Gripper Manipulated by a Robotic Arm
Authors: Cianciotto Bryce , Price Derek , Spencer Logan , Garcia Martin , Tekes Ayse
Published: January 2022

This study presents the design and development of a tendon-driven soft gripper manipulated by a 4 DOF robotic arm. The proposed robotic arm and gripper explore new areas focusing on increasing the grasping performance of the gripper as well as the workspace. The gripper is designed with 3 fingers and driven by tendons using two servo motors. The tension of the strings is adjusted using a pulley mechanism and a string. The opening and grasping of the soft gripper are accomplished by each motor. The wide opening allows the gripper to grasp larger objects. The parallel robotic arm motion is actuated using 4 motors. These motors are mounted on a spherical shoulder plate with attached circular plates with angled axles are. The axles are angled so that their axes of rotation converge to the center point of the shoulder plate. The vertical and lateral motion of the robotic arm is controlled by the series of radial linkages connected to the motors, with a parallel linkage attached to the radial linkages to actuate the forearm of the mechanism. The robotic arm is 3D printed in polylactic acid (PLA) and the monolithic soft gripper is 3D printed in thermoplastic polyurethane (TPU). The gripping force applied by the gripper is obtained using flexible sensors attached to the tip of the 3 fingers. The finite element analysis is performed in SoldWorks and the link lengths are optimized to trace the desired workspace. The mechanism is tested for its grasping and lifting of various objects showing promising superiorities in terms of its grasping capabilities mimicking the human hand. If the robotic arm is mounted on a moving platform, then it can serve as an assistive robot for the elderly.
Experimental Characterization of Hygrothermal Aging: Competition Between Thermo-Oxidation and Hydrolysis Phenomena
Authors: Shaafaey Mamoon , Bahrololoumi Amir , Alazhary Sharif , Mohammadi Hamid , Dargazany Roozbeh
Published: January 2022

In this work, we have presented a comparison between effects of accelerated thermo-oxidative, hydrolytic and hygrothermal aging on the mechanical and chemical properties of a polyurethane based (PUB) adhesive. The adhesive is a flexible adhesive which is extensively used in automobile industry as a glass sealant. During service life it gets exposed to the hygrothermal environment and the integrity of matrix interface is most vulnerable. This study focuses on weighing and comparing effects of different aging environments on material behavior; and it shows that hygrothermal aging environment results as a competition between two sub-aging phenomena i.e., thermo-oxidation and hydrolytic aging. Samples were exposed to 0%RH, 80%RH and submerged condition in distilled water. Uni-axial tensile tests, and cross-link density analysis by swelling test were carried out on as-received and aged samples. The aging process was conducted at three different temperatures (60°C, 80°C and 95°C) and for four different exposure durations of 1, 10, 30, and 90 days. This work confirms that the effect of hygrothermal aging is a result of competition between thermo-oxidation and hydrolytic aging environments. The total mechanical and environmental damage incurred by specimens is a collaborative effect of all exposure environments involved i.e., aging time, temperature, oxygen, water and humidity. The results are in agreement with the chemical test outcomes as well.
Probing the Role of Venting and Evaporative Cooling in Thermal Runaway for Small Format Li-Ion Cells
Authors: Parhizi Mohammad , Crompton K. R. , Ostanek Jason
Published: January 2022

In the present study, a lumped capacitance, 0-D model was developed for simulating thermal runaway of Li-ion battery cells. The model accounts for multi-mode heat transfer, physics associated with gas generation, evaporation of liquid electrolyte, and venting of gases out of the cell during thermal runaway. The model was exercised for two different cases of oven test and external heater. It was found that the role of evaporative cooling changes depending on the state of the decomposition reactions at the time of vent-activation. For oven tests with low temperature and for external heating at slow rates, the energy budget is delicately balanced between decomposition reactions and heat exchange with the surroundings. In these scenarios, the evaporative cooling has a significant effect, and the characteristic temperature decrease after venting is observed. Under faster heating scenarios, vent activation occurs at a time when the decomposition reactions are underway. The evaporative cooling effect is less significant in these scenarios, and the temperature vs. time signature does not show the characteristic temperature decrease. The model presented in this work provides a useful tool for parameter identification, sensitivity analysis, and probing the effects of gas generation, evaporation, and venting.
A New Approach to Develop an Intelligent Robotic Gripper Using Virtual Tools Implementing IIoT and ML Technologies
Authors: Guerra-Zubiaga David , Block Logan , Ricketts Adam , Faile Jacob , Dickson Charlie
Published: January 2022

Industrial manufacturing companies face the challenge of adapting to increasingly complex demands, especially with the influx of online ordering. One case of this is in the underperformance of end-effectors, limiting the adaptability of robotic arms in manufacturing functionality. To create proper gripper adaptability, intelligent gripper design is required to improve the sensibility and processing capability of the end-effectors. This will allow for grippers to perform effective decision-making and optimize production. This paper suggests a methodology that includes a step-by-step design process for an intelligent gripper and discusses how to develop intelligence utilizing key components of Industry 4.0 (Internet of Things, machine learning, and cloud manufacturing). This method was analyzed in a case study of a low-level intelligent vacuum gripper design. The methodology will be beneficial to intelligent gripper design from multiple levels of intelligence, creating a guide for engineers to follow to effectively design intelligent gripper solutions for their systems.
Resilient Cyber-Manufacturing Systems Under Cyber Attacks
Authors: Espinoza-Zelaya Carlos , Moon Young
Published: January 2022

The concept of cyber-manufacturing systems (CMS) is at the nexus of manufacturing advances by an interdisciplinary effort from engineering, computer science, and information science fields. Future manufacturing will increasingly be characterized by complex, networked cyber-physical systems that may be instantiated in one physical location but distributed across many. However, this vision of an interconnected manufacturing environment ushers in the challenge of new security threats to production systems that still contain traditional closed legacy components.

How to address the system failures caused by cyber-attacks remains one of the main success factors in the widespread adoption of CMS. The aim of this research is to investigate the resilience of such a system in the face of cyber-attacks. In general, “resilience” refers to the ability of an entity to withstand unforeseen environmental perturbations or disturbances while continuing performing its intended functions successfully. A resilient CMS is a manufacturing system capable of detecting, withstanding, and recovering from failures while still fulfilling its expected levels of service with acceptable levels of security, integrity, and profitability. Particularly, the resilience from failures caused by cyber-attacks is the focus of the research. A resiliency measure, evaluation of system impacts, and selection algorithm of resilient mechanisms have been explored.
Microwave Synthesis of Plant-Based Supercapacitor Electrodes for Flexible Electronics
Authors: Mehta Siddhi , Jha Swarn , Stewart Weston , Liang Hong
Published: January 2022

Renewable energy and environmental preservation are two grand challenges in our society today. To address these two challenges, there is an increasing demand for energy storage devices made of green and biodegradable materials. State-of-the-art plant-based electrodes have problems of poor electrochemical performance, low reliability, and high manufacturing cost that pose major limitations in their use in flexible supercapacitors. In this research, a novel microwave irradiation synthesis is used to produce a high-performing electro-active lignin-based biomaterial. MnO2 particles are deposited on these lignin-based materials to impart pseudo-capacitance property. These electro-active materials were coated on an Al substrate and used as an anode with an AC-based cathode. A quasi-solid-state supercapacitor was assembled using a polymer-based gel electrolyte of PVA/H3PO4. SEM was performed to study morphology, porosity, and polydispersity of the lignin-based matrix. Cyclic voltammetry (CV) was employed to study the polarization resistance of the system. The cyclic charge-discharge (CCD) was performed to observe cyclic performance. The assembled supercapacitor exhibited a specific capacitance of 26 mF/g after 500 cycles with capacitance retention of ∼87% at 0.1 A/g. This work provides new insights into the synthesis of low-cost and scalable plant-based flexible supercapacitors.
Thermodynamic Performance Study of Diesel-Fueled SOFC Power Generation System
Authors: Wang Heng , Zhao Hongbin
Published: January 2022

In this paper, the diesel-fueled CLHG-SOFC system is proposed, which can separate CO2 without energy consumption while achieving efficient power, and only H2 enters the anode, which can effectively avoid the problem of carbon deposition. Meanwhile, the SOFC system of diesel autothermal reforming and steam reforming is also established. Under the condition of ensuring the same input parameters of the three systems, the variable working condition analysis and exergy analysis are carried out, and the curves of the performance parameters of the three systems with the change of fuel flow and the exergy destruction diagram of each component are obtained. In addition, the results of the three systems are compared. The results show that although the power of diesel steam reforming SOFC is the highest, the total power efficiency of the system is not the highest because it needs electric heating. Diesel autothermal reforming SOFC has the highest total power efficiency and exergy efficiency. CLHG-SOFC system has the lowest efficiency, but it can recover CO2 and avoid carbon deposition in SOFC, which is not available in the other two systems. The research results not only provide theoretical basis and scientific support for the design of SOFC power generation system based on diesel fuel, but also provide a new scheme for energy saving optimization of power generation system.
Computational Fluid Dynamics Turbulence and Wake Study of a Utility-Scale Rotating Three-Blade Horizontal Axis Wind Turbine
Authors: Al-Qarishey Hussein , Fletcher Robert W. , Alkareem Elaf Abd
Published: January 2022

Wind turbines deployed in utility scale wind farms can help to meet future energy demands and reduce carbon dioxide emissions by reducing energy needs from fossil fuels. Wind turbines, however, produce downstream wakes and turbulence. In wind farms such turbulence can negatively impact power production of downstream turbines. It is critical, therefore, to understand this downstream turbulence, but this is challenging. Wind farm layouts are costly and mandate advanced analysis and sophisticated simulations be done to define a wind farm configuration long-before its construction. This is usually done using high-speed computers, and even super computers, to simulate and analyze downstream conditions. In this work the successful deployment of Computational Fluid Dynamics (CFD) using a desktop workstation to study downstream turbulence and wakes of a single utility-scale, rotational three-blade horizontal axis wind turbine (HAWT) are presented. A three-dimensional flow field assuming incompressible flow and unsteady state SST k-ω (two equation) turbulence model was constructed using an unstructured grid around an operational typical utility size HAWT with a rotor hub elevation of 80 meters and a blade length of 40 meters rotating at 18 RPMs. Various wind velocities of up to 25 meters per second providing pressures and velocities were successfully studied.
Standardizing the Process Information for Machining Operations Through Self-Contained Structures
Authors: Asghar Eram , Tolio Tullio , Ratti Andrea
Published: January 2022

A mechanical product is manufactured through multiple processes and procedures. The process information is coded in a part program, and a large amount of unstructured information comes from the shop floor. This results in the loss of logic formulated for the creation of a code. Moreover, it is impossible to track the modifications carried out during these processes. Thus, the unavailability of appropriate and standard knowledge of part processing leads to the situation where the information must be recreated every time a similar part is manufactured, hence, increasing the process planning time. One solution is to divide it into two steps: first, by fetching the information and coding it in a standardized structure; second saving it in a suitable form, facilitating in improving the efficiency and effectiveness of process design for available parts as well as anticipating the new parts. This was achieved by using the previous information related to the process combined with the one obtained from the shop floor. The proposed work concerns capturing the unstructured information from the existing part programs and regaining it using process simulation (VERICUT). Through the extraction of theoretical and graphical geometric data, the interactions between the operations were analyzed. The operational knowledge in this work includes: origin, feed-rate, rotating speed of the tool, rapid movement, cutting tool, material knowledge, and some geometric information of the process. The proposed approach based on simulations and mathematical programming logic is a way to improve flexibility at process and system level by formalizing the available operational knowledge. To illustrate the applicability of the proposed approach, a case study was carried out on a real industrial part program.
Investigating the Effects of Branching on the Constraint-Embedded Swept Profile Calculations
Authors: Aras Eyyup
Published: January 2022

One of the most significant issues investigated in the CAD/CAM developments is the swept envelope formation by a moving tool. There is many attempts to get envelopes, based on the evaluation of tangency constraint. The core operation of this method is to pick the input values one at a time and consider the solutions of constraint for various dependent values at a particular time instance. Such a pathway causes excessive computational effort and time that must be spent to implement the tangency constraint. Recently some research [15,17] has been conducted to completely eliminate the need for evaluating tangency-constraint. In these techniques in order to obtain a closed-form representation of the envelope, the tangency constraint is written explicitly in terms of the dependent variable then it is embedded into the tool surface equation. While these sound straight forward, there are some important inevitable consequences of these restructurings. In the new form, there are no restrictions on the domains of the input variables. On the other hand, for the form-cutting tools the whole set of input values need to be partitioned into a number of disjoint ordered-subsets for which correspondence check between domain and eliminated variables must be performed. The computational cost associated with this type of calculation can become impractical when looking at all the benefits we get from eliminating the tangency-constraint evaluation. To overcome this issue, in this paper first, we introduce a powerful test that takes the domain restrictions into account. Later, using this test we will systematically investigate the distribution patterns of swept profiles. Finally, we present algorithms for forming the domains of closed forms under different motion kinematics.
Studying the Superfluid Transformation in Helium 4 Through the Partition Function and Entropic Behavior
Authors: Domenikos G-R. , Rogdakis E. , Koronaki I.
Published: January 2022

On this paper the authors study the behavior of Superfluid Helium 4 near and below the Lambda line deriving its partition function. The partition function is split into an interacting and a non-interacting/ideal part. Hence, the models about the Bose-Einstein Condensation of an ideal Bose-Gas are applied to the non-interacting/ideal part and then the results compared to the full superfluid, described by the quasiparticle approach. The transition from the Bose-Einstein to the Maxwell-Boltzmann statistics in the non-interacting part is exhibited extremely near the lambda transition of the actual superfluid Helium, hinting the effect of superfluidity in the ideal part of the system. Thus, the complete statistical model is now designed and calibrated by the known experimental data for its interacting part. With this model, since it is a theoretical method based on the partition function and entropy, not on the energy values of the quasiparticles, there is no theoretical limit to the lowest temperatures it can possibly describe. This entropic approach when extended well below the lambda-line, going near absolute zero, predicts the existence of an interatomic potential even at absolute zero, something that has been known to be the case for superfluid Helium. Overall, it seems that by the calculation of the authors the behaviors of superfluidity can also be observed and derived by studying the macroscopic variables, being the partition function and entropy in this way, thus offering a view of the superfluidity of the system through a different more macroscopical scope.
Continuous Equation of State and Thermodynamic Maps for Cryogenic Helium 4
Authors: Domenikos G-R. , Rogdakis E. , Koronaki I.
Published: January 2022

On this paper the authors present a unified EOS for Helium 4 below its liquidation and towards absolute zero. While such EOS’s exist in the literature, they are divided to different region depending on temperatures and pressures, but in this work an overall equation has been created using all the available data and different methods. Thus, the provided equations offer a solid point of reference for any cryogenic engineering applications as they cover to a very high accuracy all the known data and combine them in a ready to use form for any application. Additionally, because of the availability and continuity of the equations covering the entire Fluid, Superfluid and Lambda spectrum thermodynamic maps can now be created for both Helium 4, giving the tools to directly study thermodynamic cycles on maps as done in higher temperatures. The equations that describe the thermodynamic characteristics are offered in two different forms, one of high accuracy with large number of terms, and one with lesser but adequate accuracy with less terms to be used for quicker calculations. Overall, this set of equations can be used to describe the working medium in any cryogenic application using Helium 4 without the need to differentiate one’s models and equations depending on the temperature and pressure regions, meaning that the same model can be used to describe even different phases of Helium 4 in the same application.
KrakenBox: Deep Learning-Based Error Detector for Industrial Cyber-Physical Systems
Authors: Ding Sheng , Morozov Andrey , Fabarisov Tagir , Vock Silvia
Published: January 2022

Online error detection helps to reduce the risk of failure of safety-critical systems. However, due to the increasing complexity of modern Cyber-Physical Systems and the sophisticated interaction of their heterogeneous components, it becomes harder to apply traditional error detection methods. Nowadays, the popularity of Deep Learning-based error detection snowballs. DL-based methods achieved significant progress along with better results. This paper introduces the KrakenBox, a deep learning-based error detector for industrial Cyber-Physical Systems (CPS). It provides conceptual and technical details of the KrakenBox hardware, software, and a case study. The KrakenBox hardware is based on NVIDIA Jetson AGX Xavier, designed to empower the deep learning-based application and the extended alarm module. The KrakenBox software consists of several programs capable of collecting, processing, storing, and analyzing time-series data. The KrakenBox can be connected to the networked automation system either via Ethernet or wirelessly. The paper presents the KrakenBox architecture and results of experiments that allow the evaluation of the error detection performance for varying error magnitude. The results of these experiments demonstrate that the KrakenBox is able to improve the safety of a networked automation system.
Efficient Joining Sequence Variation Analysis of Stochastic Batch Assemblies
Authors: Sadeghi Tabar Roham , Lindkvist Lars , Wärmefjord Kristina , Söderberg Rikard
Published: January 2022

Geometric variation causes functional and aesthetic problems in the assemblies. The challenge is predicting the moments of the distribution of geometric deviations of assemblies to evaluate compliance with the set requirements. Variation analysis of non-rigid sheet metal assemblies with respect to the geometric quality is traditionally performed using Method of Influence Coefficient (MIC), based on Finite Element Method (FEM). The joining operation is one of the most crucial steps in the assembly process, imposing forces on the parts and causes bending and deformation during the assembly, consequently contributing considerably to the final geometric outcome of the assembly. To model the behavior of the assembly realistically and achieve accurate simulation results, considering the sequence of joining is essential. In a digital twin of the assembly process, where the scanned geometry of parts are available and the assembly parameters are optimized for a batch of fabricated components, joining sequences need to be provided for the optimal geometric outcome of the batch of assemblies. The sequence optimization of the joining processes is a time-consuming combinatorial problem to solve. Variation analysis of non-rigid assemblies with stochastic part inputs, including optimal joining sequences, requires an extensive amount of computational effort. More efficient approaches for evaluating assembly geometric variation are desired. In this paper, a computationally efficient approach is proposed for geometric variation analysis and optimization of non-rigid assemblies with stochastic part inputs with respect to the joining sequences. A clustering approach is proposed categorizing the incoming parts based on the part variation. Sequence optimization is performed, and geometric variation is analyzed for each cluster. The results show that the proposed method drastically reduces the computation time needed for sequence optimization compared to individualized optimization for each assembly.
Design and Development of a Reconfigurable and Adjustable Compliance System for the Measurement of Orthotic Properties
Authors: Mo Yaru , Qaiser Zeeshan , Johnson Shane
Published: January 2022

Custom foot orthoses (CFOs) are effective in the prevention and treatment of lower extremity injuries (LEIs). However, the current design methodologies of CFOs are not efficient due to the limited consideration of soft tissue impedance, orthotic properties and subjective feedback during the measurement. A new design methodology of CFOs is required to determine the desired orthotic properties including geometry and impedance, which satisfy pressure/load distribution, subjective comfort and reduce iterations. A measurement device which provides an Interface with Tunable Ergonomic properties using a Reconfigurable Framework with Adjustable Compliant Elements (INTERFACE) is developed. The INTERFACE system provides locally adjustable geometry and stiffness for the support of Medial Longitudinal Arch (MLA) by applying a mechanism with six degrees of freedom and three Tunable Stiffness Mechanisms (TSMs). Therefore, the Rapid Evaluate and Adjust Device (READ) Methodology can be implemented by adjusting the interface properties based on the pressure/load and subjective evaluation. The prototype of the INTERFACE system was fabricated to conduct the validation test on 10 subjects, in which the interface pressure/load distribution and subjective feedback in different combinations of geometry and stiffness were recorded. The plantar pressure/load increased with stiffness and geometrical height, and the significance has been demonstrated by a correlation analysis. Subjective comfort can be achieved with different combinations of geometry and stiffness. The proposed INTERFACE system can be employed to conduct the plantar measurement to obtain the desired orthotic properties which satisfy objective and subjective requirements.
On the Vaporization Rate and Flame Shape of Non-Spherical Droplets
Authors: Palmore John
Published: January 2022

Motivated by the study of spray combustion, this work addresses the combustion of non-spherical droplets. The combustion of spray is usually understood through the theory of droplet combustion, and improving this latter theory is the narrow aim of this work. The current work uses perturbation theory to derive a novel model for the vaporization of non-spherical droplets. Compared to previous efforts in this area, the work uses a physics-based approach by incorporating ideas from the asymptotic analysis of Taylor and Acrivos [J. Fluid Mech., 1964]. The perturbation strategy expands the droplet shape using spherical harmonics, and the theory characterizes the shape of the droplet via the Weber number. The introduction of this parameter is key as it is a parameter that can be easily measured in experiments, and thus it can be used to connect the theoretical results with application. The perturbation analysis is performed based around the classical solution of spherical droplet combustion in quiescent flow. The theory indicates that the effect of droplet deformation can be accounted for by a correction to the droplet combustion rate that is simple polynomial function of the droplet Weber number. Results are compared to existing literature, and it confirms the established trend that deformed droplets vaporize faster than spherical droplets. Analysis of the flame shape reveals that the flame remains nearly spherical, however, the mean flame standoff changes with droplet shape. The extension of the theory to high Reynolds number conditions is briefly discussed.
Thermal Performance of Heat Recovery From Gas Turbine Exhaust Stacks Using the Silencer Upstream Sections
Authors: Faqihi Bouria , Ghaith Fadi A.
Published: January 2022

This paper aims to evaluate the potential of incorporating a novel heat recovery method within the simple cycle gas turbine exhaust stacks. The proposed heat recovery system consists of the existing semi-circular sections (nose) of the silencer baffles. In this heat transfer model, gas turbine exhaust air represents the hot side which flows across the parallel silencer baffles. The cold side stream flows inside the semi-circular sections. The proposed heat extraction system offers an advantage of utilizing waste heat from the exhaust stream, without instigating additional pressure drop on the flow.

In this work, heat transfer analysis was carried out to estimate the availability of sufficient surface areas in the aforementioned sections of the silencer. The proposed model was implemented for the application of fuel gas heating such to enhance the gas turbine cycle performance.

The obtained results showed that by using the nose section area of the silencer baffles only, it was possible to recover about 2.7 MW from the total energy available in the exhaust which is normally released in the simple cycle gas turbine exhaust stack. The extracted heat met almost 54% of the heat required to heat the fuel gas in the performance heater.

The paper also presented further enhancements that can be incorporated, such as utilizing the downstream end of the silencer baffles. In addition, the proposed system can reduce fuel consumption, while avoiding undesired pressure drop in the exhaust system.
A Special Strategy for Quadrotors in Aggressive and Singularity-Free Tracking
Authors: Liu Haowen , Yang Bingen
Published: January 2022

Quadrotors are a popular type of unmanned aerial vehicles (UAVs) that have been widely used and extensively researched in recent years. Quadrotors, while exhibiting high agility in maneuvering, generally lack stability. There exist several types of instability in modeling and control of quadrotors. During an aggressive maneuver process, a traditional quadrotor model developed based on Euler angles may encounter singularities due to the Euler sequence. This type of instability can be avoided via quaternion-based modeling.

Although quaternion-based models can eliminate the singularities due to the Euler sequence, there still exist other types of singularities for maneuvers in head-direction and thrust-direction. A UAV usually equips with a camera or other type of sensing device, which is mounted on the front or top of the U AV and which points towards the forward direction. Keeping those sensing devices pointing at the desired orientation can be a difficult task because the definition of reference heading direction vector introduces singularity and renders the mixer of the quadrotor saturated. As a result, the UAV becomes unstable.

In this article, a special strategy in dealing with the head-direction-induced singularity and saturation is proposed. In this strategy, pre-yawing is adopted when a quadrotor’s current heading direction is approaching singularity. As shall be shown, by pre-yawing before the quadrotor passes through the singularity, the quadrotor can converge toward the heading direction faster after exiting the singularity. Also, the pre-yawing strategy can reduce or avoid mixture saturation by reducing the feedback error. Consequently, the proposed strategy can also reduce the deviation from the desired trajectory. The benefits of this new control strategy in tracking are demonstrated through comparison with existing quadrotor models in the literature.
Effect of Self-Actuating Flap on the Aerodynamic Performance of Flat Plate Wing at Low Reynolds Number
Authors: Verma Anand , Kulkarni Vinayak
Published: January 2022

Experimental analysis is performed to study the effect of a self-actuating flap on the aerodynamic performance of flat plate wings at Reynolds number of 90,000 based on their chord length. Here two different aspect ratios (AR = 1,2) of wing models are chosen to study in open circuit low-speed wind tunnel with and without the presence of effectors. The flap is mounted at the two locations (06c, 0.7c) on the suction surface of the wings. The flow around the wing section controls the opening and closing of the flap. It has been seen for a smaller angle of attack that flap remains attached to the wing surface, but after certain pitching angles, the flow separation initiates to occur along the trailing edge, which lifts the flap and adjusts itself in a situation, so as to attach the flow. The lift and drag characteristics for pre-stalled angles are almost similar to both clean and flapped models. Further, all the flapped configurations exhibited a higher value of lift coefficient for high or post-stall angles than the clean models. No significant changes are seen in drag characteristics for clean and flapped configurations for aspect ratio 1. In the AR = 2 model, approximately the same aerodynamic performance is seen with both the locations of the flap, but for AR = 1 configurations, the flap is more effective when it is located at a position of 60% of chord length. For AR = 2 clean flat plate, the CLmax is found as 0.71 at 12°, and flapped models have the CLmax as 0.74 at 18° angle of attack.
A Convolutional Neural Network (CNN) for Defect Detection of Additively Manufactured Parts
Authors: Parvez Mohammad Masud , Rahman Musarrat Farzana , Galib Shaikat M. , Liou Frank
Published: January 2022

Additive manufacturing (AM), fundamentally different from traditional subtractive manufacturing techniques, is a layer-by-layer deposition process to fabricate parts with complex geometries. The formation of defects within AM components is a major concern for critical structural and cyclic loading applications. Understanding the mechanisms of defect formation and identifying the defects play an important role in improving the product lifecycle. While convolutional neural network (CNN) has already been demonstrated to be an effective deep learning tool for automated detection of defects for both conventional and AM processes, a network with optimized parameters including proper data processing and sampling can improve the performance of the architecture. In this study, for the detection of good deposition quality and defects such as lack of fusion, gas porosity, and cracks in a fusion-based AM process, a CNN architecture is presented comparing the classification report and evaluation of different architectural settings and obtaining the optimized result from them. The performance of the network was also compared with the results from the previous study. The overall accuracy (98%) for both training and testing the CNN network presented in this work transcends the current state of the art (92%) for AM defect detection.
Towards Smart Vaccine Manufacturing: A Preliminary Study During COVID-19
Authors: Kumar Vishnu , Srinivasan Vijay , Kumara Soundar
Published: January 2022

Biopharmaceutical community is devising modern techniques to boost the development, production, and distribution of COVID-19 vaccines in large scale with tremendous speed. This has shifted the focus towards smart manufacturing of vaccines through vaccine platforms. Vaccine platforms have great potential to rapidly generate new vaccines and can overcome the challenges of the traditional vaccine manufacturing approach without compromising on safety and efficacy. This preliminary study compares the traditional and modern vaccine manufacturing techniques, reviews COVID-19 vaccine manufacturing scenarios, and presents a framework to critique on the smartness of the novel platform-based COVID-19 vaccine development and manufacturing.