bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Mathematical Model to Predict Alkaline Electrolyzer Performance Based on Basic Physical Principles and Previous Models Reported in Literature
Authors: Antoniou Antonios , Celis Cesar , Berastain Arturo 
Published: January 2022

Abstract
Hydrogen production through electrolysis is an important research topic since the use of hydrogen as a fuel has the potential to significantly reduce gaseous emissions in near future. The electrolytic splitting of water into hydrogen and oxygen can be carried out using for instance electricity generated from renewable energy sources such as solar radiation. Electrolysis processes occurring in electrolyzer cells are complex phenomena and a clear and accurate mathematical representation of the referred processes is vital to accurate predict electrolyzer cells performance. So a comprehensive mathematical model capable of properly describing alkaline electrolyzer cells performance, in terms of efficiency and hydrogen production rate, is proposed in this work. The mathematical model is based on several physical concepts such as energy losses due to electron and ion transfer, entropy increase, electrolyte flow rate, and electrolyzer physical structure and construction material. Compared to existing models, the new proposed one is more complete as it includes more operational parameters (six) affecting cells performance. Once developed, the proposed model has been fine-tuned using experimental data available in literature. The results obtained using the new developed model are in good agreement with Ulleberg’s experimental data. Based on the work carried out here, it is concluded that developing a mathematical model based on physical principles is crucial in the comprehension of electrolysis related processes and how to utilize them in the simplest and most reliable way.
Finite Element Model of a Cultured Vascular Smooth Muscle Cell Subjected to Uniaxial Stretch: Effect of Orientation Angle of Stress Fibers on Biomechanical Responses
Authors: Tamura Atsutaka , Makabe Kei , Yamashita Hatsune , Hongu Jun-ichi 
Published: January 2022

Abstract
Vascular smooth muscle cells (SMCs) in the extracellular matrix adapt to their surrounding environment in vivo with its contraction and relaxation. As blood pressure increases, the circumferential stress on the aortic wall also increases. The major components of the media are SMCs, so SMCs should regulate the vessel diameter and the mechanical balance of the aortic medial ring.
Thus, it is important to clarify how external forces on SMCs are transmitted through the intracellular components. Nuclei may sense changes in the applied mechanical stretch via stress fibers (SFs) or focal adhesions (FAs). However, there is little quantitative information available about the mechanical contribution of SFs and FAs to whole-cell mechanical events such as uniaxial stretching.
In the present study, therefore, we developed a finite element model of a cultured SMC, with contractile SFs, on a silicone substrate, and applied a uniaxial stretch, to investigate the mechanotransduction pathways involved in SMCs. We revealed that the initial orientation angle of the SFs was closely correlated with their resultant stretch, and the magnitude of the biomechanical force exerted by SFs.
Effect of Hole Diameter Deviation on Temporary Fastening Damage of Composite Materials
Authors: Yan Chen , Lin Yujin , Wang Hua 
Published: January 2022

Abstract
Temporary fastening technology has become an essential process in the aviation assembly process due to its functions such as eliminating the initial gap, suppressing the hole-making gap, and increasing the positioning accuracy. However, with the increasing proportion of carbon fiber reinforced polymer used in aviation, new problems have emerged in the installation of temporary fasteners: The contact area between the clamping feet and the composite hole is small. Excessive clamping force will cause damage to the periphery of the composite hole, which brings severe hidden dangers to the bearing capacity and durability of the aircraft composite structure. The deviation of the aperture at the assembly site will obviously aggravate the severity of this situation. Therefore, the size of the temporary fastener installation aperture needs to be carefully studied. In this paper, an FEA model is established in the Abaqus to investigate the effect of aperture deviation on temporary fastening damage. The model includes the reverse model of temporary fasteners and the composite laminates with holes. The 3D Hashin criterion is used to describe the failure of composite materials, the user material subroutine (UMAT) is written to predict the temporary fastening damage process of composite members, and the validity of the model is verified by comparison with experimental results, and the simulation of complex failure damage around the composite hole is realized. The established model is used to explore the influence of the installation aperture’s deviation on the temporary fastening damage of the composite component. The effect of the temporary fastener clamping feet’ installation direction and the degree of the temporary fastener’s off-axis is analyzed in detail. The results show that the deviation of the hole diameter will significantly impact the installation damage of the temporary fasteners of the composite member. As the installation aperture increases, the clamping force that can be applied by the temporary fastener gradually decreases. The installation direction of the clamping feet has little effect on the damage around the composite hole. The off-axis of the temporary fastener will cause serious damage to the composite hole. This paper has also obtained the mapping relationship between the maximum load-bearing clamping force around the composite hole and the hole diameter under the two conditions of no damage and limited damage. This paper’s research results will provide guidance for the tolerance design of the mounting holes on the assembly site and the installation of temporary fasteners to avoid unexpected installation damage to the high-value composite components caused by the temporary fastening process.
Spray-on Capacitive Proximity Sensors in 3D Printed Robotic Links
Authors: Detzel Samuel , Krieger Yannick S. , Hoefer Robert W. , Robe Anton , Sigling Annette C. , Lueth Tim C. 
Published: January 2022

Abstract
Proximity sensors are crucial components for any robotic system working in collaboration with humans. We integrated for the first time proximity sensors into 3D printed robotic links by realizing internal sensor electrodes with graphite spray coating. This method is perfectly suited for the manufacturing of specialized and individualized robotic systems or rapid prototyping. After design and fabrication of corresponding robotic links with appropriate inner chambers by selective laser sintering (SLS), graphite spray coating was applied to generate internal capacitor electrodes. Excellent sensor and detection properties were obtained. The proximity detection range proved to be indistinguishable from that of sensors made from conventional sheet metal. In addition to the advantage of enabling a simple integration of proximity sensors in different robotic link geometries, the sensor is protected from environmental influences due to its internal placement. Conductive spray paint allows us to cover even two-dimensionally curved surfaces. This way, the electrode areas can be maximized. The concept and its realization as well as the experimental results concerning the sensor properties and a 4R serial robot are shown in this paper.
Evaluating Piping Supports Modification to Mitigate Slug Flow Induced Vibration Utilizing Time-History/Response-Spectrum Approach in a Rich Amine Column NPS 30 Inlet Piping System
Authors: Herrera Sierralta Carlos , Al-Muslim Husain 
Published: January 2022

Abstract
Preventing potential failure in pipework due to fatigue induced vibration provoked by slug flow is a critical part of detailed engineering design phase as these types of failures have been evidenced across the industry, and particularly in the oil and gas sector leading to significant incidents.
Slug forces are generated at change of direction of piping systems (i.e: elbows, tees, branches, and laterals) due to change of momentum of the fluid in two-phase flow regimes; The order of magnitude of such slug forces depend on the process stream properties, and in the relation between the two phases liquid and gas converging into the same pipework.
In order to address this concern, the piping designer typical approach is to conduct the static equivalent method where dynamic loads are converted to static loads in the piping flexibility analysis. In this approach, the designer estimates the slug force by selecting the most conservative combination of both variables, density and velocity of the slug, which is multiplied by the internal sectional area of the pipe, where the slug load is expected to occur. The resulting slug force is then typically multiplied by 1.5 to 2.0 in order to take into account the dynamic load factor.
The resulting slug forces are applied at all the affected changes of directions as a constant force in the piping flexibility analysis. While this approach is routinely followed as it is typically conservative from the piping flexibility static load cases perspective, it does not simulate the real dynamic conditions of the piping system, as it does not consider the influence of the slug forces occurring as a function of time, wherein reality, not all the slug forces are occurring at once at any given time, but occurring sequentially as the fluid travels through the length of the pipe, impacting the elbows in a progressive order, which directly dependents on the velocity of the fluid and the estimated length of the slug.
Therefore, this approach may not be reliable to evaluate existing systems with high vibration due to the high level of confidence required before proceeding to perform field modifications.
This paper describe over a real case example, an alternative methodology which allowed to determine the dynamic interaction of the slugging forces by utilizing the Time-History assisted by Response-Spectrum, both available within common piping flexibility analysis software.
The methodology allowed to resolve the piping vibration problem on subject by re-designing the associated spring and supports, without reducing the gas treatment plant production rates nor shutting down the facility.
The original design and modification of NPS 30 piping inlet to a Rich Amine Column is discussed along with results of both flexibility analysis and field vibration measurements before and after the modification.
Fast Methods for Nonlinear Vibration Analysis of Variable Stiffness Panels
Authors: Andérez González Jorge , Vescovini Riccardo 
Published: January 2022

Abstract
This paper presents an approach for the nonlinear vibration analysis of Variable Stiffness (VS) plates based on Third-order Shear Deformation Theory (TSDT) along with a mixed variational formulation. The unknowns are expanded using the Ritz method, whilst time dependency is handled by referring to the Differential Quadrature (DQ) and the Harmonic Balance (HB) methods. The proposed framework guarantees reduced computational time, which is of particular interest when exploring the large design space offered by variable stiffness configurations. Validation against reference results is presented, as well as exemplary parametric studies illustrating the potential of the approach.
Deep Learning for Drag Coefficient Predictions of Spherical and Non-Spherical Particles
Authors: Mahyawansi Pratik , Lin Cheng-Xian , Chen Shu-Ching 
Published: January 2022

Abstract
The drag model for non-spherical particles required in a particle-laden flow is not fully established, which could cover a wide range of sphericities. This study focuses on developing an artificial neural network model by using a large number of available experimental data for a wide range of sphericities (0.034–1), density ratios (0.0005–0.491), and Reynold numbers (0.002–79432). Available experimental and DNS data for particles of various sizes and materials tested against liquid and gas are identified to correlate the drag coefficient. Three different neural network algorithms, Random Forest, Gradient Boosting, and a Deep Neural Network (DNN), are trained and evaluated. The neural network results were compared to the experimental results and to select numerical correlations. It was found that the DNN model outperforms all the other methods and algorithms for most of the studied sphericities (0.36–1).
A Novel Trilogy of e-STEM Programs
Authors: Gharib Mohamed , Katbeh Tala , Cieslinski G. Benjamin , Creel Brady 
Published: January 2022

Abstract
In recent years, pre-college educational programs have been introduced to increase the interest and supply of skillful people to work in STEM fields. While the emphasis has previously been primarily focused on the content of project-based learning programs, another factor that needs to be accounted for is the accessibility of the said programs. Unprecedented issues such as the sudden closure of educational facilities, as was experienced during the COVID-19 pandemic, should not hinder the learning opportunities that the students are after. Therefore, the shift from hosting conventional STEM programs to online platforms has become a crucial element in the expansion of STEM education. Delivering engineering-based projects through online STEM programs to school students includes wide expansion of the participating audience — which is not confined by the capacity limit of in-person programs — as well as ease of access. This has value not only on the individual level but also at the social level.
Three successful e-STEM (electronic STEM) programs are presented in this paper that are designed to support and enhance students’ learning of engineering concepts while also increasing students’ understanding of real-life applications. This has a close connection to the desire to increase online education in developing countries over recent years. The first program is called Innovate, Design and Engineer an App (IDEA). In this program, the students explore the fundamentals of programming and mobile app development. This provides the students with the foundation of coding, algorithms, and refining their ideas to produce a working mobile phone app that is created to meet a specified challenge. The second program is called Creative Fusion and Innovation (CFI). In this program, the students learned the basics of creating, editing, and analyzing their 3D designs; recognize the importance of creating 3D models in engineering; and understand how 3D printing works as they create their own 3D models. The third program is called Virtual Robotics Games (VRG). In this program, the students learn the fundamentals of designing, building, programming, and testing robots in a virtual environment. Through this program, the students learn the basics of robot design in addition to coding and simulation, which are all necessary tools for aspiring engineers.
These programs aim to provide STEM education access to build communities specifically in engineering, which is in high demand. Throughout these programs, the students are able to learn important computer skills and the concepts of the engineering design process. The programs also equip them with the required knowledge and problem-solving skills to tackle challenges. At the end of each program, the students will have created successful designs as solutions to the real-life problems that they were tasked with. In this paper, the details behind the planning, formation and production, and implementation of the three online programs are presented.
Laser-Assisted Friction Element Welding
Authors: Grimm Tyler J. , Parvathy Gowtham Vadivel , Mears Laine 
Published: January 2022

Abstract
Governmental regulations and increasing awareness of global greenhouse gas effects have caused a need to rapidly improve energy efficiency across all industries. The transportation industry is one such sector which utilizes a significant amount of energy, thus necessitating efforts to drastically improve the fuel economy of vehicles. A well-known method for achieving this is by vehicle lightweighting, which can be done through the use of multi-material structures. Inherent to the utilization of multiple materials is the joining process, which creates new challenges since vehicles and the supporting infrastructure have traditionally been based on mainly steel designs.
Friction element welding (FEW) is a process which can effectively join aluminum sheets to steel. This process involves the formation of a friction weld between a fastening element and lower steel substrate, securing an upper aluminum sheet between the fastener head and the steel. Prior to forming the friction weld, the fastener penetrates the aluminum through frictional heat-based softening and axial load. In relatively soft alloys, the aluminum flow remains close to the fastener’s shaft. However, when penetrating harder alloys, the aluminum flows further away from the shaft, resulting in protrusion outside of the fastener’s head in the final joint. This external material can lead to accelerated corrosion. Laser power is herein explored as a method for rapidly and efficiently heating the workpiece material to preemptively soften it before joining using FEW, thereby improving the flow behavior. It was experimentally determined that laser heating is a viable augmentation of the FEW process for improving aluminum flow during penetration. Furthermore, this process does not significantly increase the processing time of FEW, as heating can be performed in parallel with other essential steps. It can also reduce the total energy consumption under certain parameters.
Numerical Simulation of Impinging Slot Air Jet in the Presence of a Cross Flow
Authors: Gudi Abhay , Hindasageri Vijaykumar 
Published: January 2022

Abstract
A numerical investigation is carried out to study the effect of cross flow on local heat transfer distribution of a flat surface impinged normally by a slot air jet using ANSYS Fluent commercial software. Initially an experimental validation study is conducted to validate the centerline Nusselt number and to fix numerical settings such as Turbulence model, optimal mesh size and solution strategy. During this study, it is observed that the k-ϵ realizable model predicts fairly accurate results (less than 10%) when compared with the experiment data and therefore used for all further simulations in the present work. Grid independence study was conducted to arrive at optimal grid size. Grid size was varied from 0.08 million cell size to 0.2 million cells with 3% variation in percentage of peak Nusselt number. It is ensured that minimum of five boundary layers are maintained in numerical grid with y+ not more than 5 for all the cases studied. Further, the influence of nozzle exit to impingement plate distance (z/d = 2 to 6) is studied for different cross flow velocity to the main jet velocity ratios (M = 0 to 1). The Reynolds number (Re) is varied from 5000 to 50000. Furthermore, the aspect ratio of the slot jet is also varied. The center-line distribution of Nusselt number along the crossflow direction is provided. From the present numerical investigations, it is found that the presence of cross flow jet may result in either increase or decrease of the peak Nusselt number. This is attributed to the vorticial structures generated from the interaction of the wall jet of the main flow jet with the cross-flow jet. For the smallest nozzle tip to plate spacing, Z/D = 2, the peak Nusselt number is observed for the highest cross flow, M = 1 at higher Reynolds number (Re = 20,000 and 50,0000). For the larger nozzle tip to plate spacing (Z/D = 4 and 6), the peak Nusselt number is observed for the intermediate cross flow (M = 1/2) at higher Reynolds number (Re = 20,000 and 50, 0000). For the highest aspect ratio of 2, it is observed that peak Nusselt number decreases with the increase in crossflow. On the contrary, the square nozzle with lowest aspect ratio of 1, it is observed that the peak Nusselt number increases with the increase in crossflow.
Experimental Verification of Model-Free Vibration Control Technique Based on a Virtual Controlled Object Considering Actuator Parameter Uncertainty
Authors: Yonezawa Ansei , Yonezawa Heisei , Kajiwara Itsuro 
Published: January 2022

Abstract
This study proposes a novel model-free vibration controller based on a virtual controlled object (VCO) considering actuator parameter uncertainty. A proof-mass actuator, which is modeled as a single-degree-of-freedom (SDOF) system, is employed. A VCO, which is defined as an SDOF system, is inserted between the actual controlled object and the actuator model. Considering frequency transfer characteristic from actual controlled object to VCO, setting appropriate parameters of the VCO realizes model-free control. A state equation to design the model-free controller is derived based on the two-degree-of-freedom (2DOF) system composed of the actuator model and the VCO. The actuator parameter uncertainty is quantitatively modeled in the 2DOF plant. Traditional mixed H2/H∞ control theory is applied for the uncertain plant to design a model-free controller with high damping performance and robustness to the actuator uncertainty. The effectiveness of the proposed controller is confirmed by vibration control experiments.
Fracture Behavior of Alumina/Epoxy Resin Interface and Effect of Water Molecules by Using Molecular Dynamics Using Reaction Force Field (ReaxFF)
Authors: Nishino Hiroki , Kanamori Kohei , Kimoto Yoshikatsu , Okada Kazuma , Yonezu Akio 
Published: January 2022

Abstract
Adhesion bonding of metals and polymers is attracting attention as an innovative bonding technology to realize high functionality and weight reduction of various mechanical parts and structural materials. This technology has been significantly demanded with the rapid development of multi-materials in recent years. However, it has been reported that natural oxide film and hydroxide film are formed on the metal surface, resulting in the change in adhesion, especially degradation of adhesion is sometimes accelerated by water molecules at the interface. The mechanism of adhesion degradation is still unclear. In this study, the interface between metal and resin was modeled using the molecular dynamics (MD) simulation to investigate how the moisture (water molecules) on the interfacial surface affects the adhesion. This study varied the amount of water molecules at the interface and investigated how water molecules affect the adhesive strength subjected to uni-axial tensile loading. In addition, the potential energy around the interface was calculated, and the adhesion mechanism with respected to water molecules was carefully discussed.
Analysis of Correlation Between Manufacturing Parameters and Mechanical Strength Followed by Uncertainty Propagation of Geometric Defects in Lattice Structures
Authors: Mang Chetra , Tahmasebimoradi Ahmadali , Lorang Xavier 
Published: January 2022

Abstract
Lattice structures are widely used in various applications, especially in aeronautic, aerospace, and medical applications because of their suitable properties. Thanks to advancement of the additive manufacturing technology, the lattice structures can be manufactured by different methods such as laser beam melting technology. However, the presence of geometric defects in the lattice structures is inevitable due to the manufacturing process. The geometric defects may have high impact on the mechanical strength of the structures. The geometric defects are directly linked to the process parameters. This paper presents the analysis of the correlation between the process parameters and the mechanical strengths. In addition, the uncertainty propagation of the mechanical strengths according to the process parameters is also studied.