bluuebunny/crossref_metadata_2025_split huggingface dataset:
Flexible Energy Harvesters for Harsh Environments: A Review
Authors: Haskell Andrew , Soltani Seyed 
Published: February 2023

Abstract
As the power consumption requirements for the electronics decreases, the notion of powering the electric circuits by harvesting the ambient energy deems more practical. Particularly, energy harvesters could be used for powering the next-generation “flexible” microelectronics capable of being stretched, bent, twisted, and deformed without affecting their normal functionality. So far, several energy harvesters have been developed by the researchers, however, less attention has been paid to the performance of the energy harvesters in harsh i.e., hot humid, environment. Thin film technologies, used to protect the MEMS energy harvesters, continue to play a key role in the development of stretchable electronics, flexible displays, and a host of other applications. Nevertheless, movable components can be exposed to cyclic loading in these applications, which can result in fatigue failure of the MEMS device, the thin film coating, or both. While the applied coating is expected to prevent the moisture and oxygen ingress into the energy harvester hence effectively improve its fatigue life in the harsh environments, it will also add such parameters to the design as the critical permeation thickness and will possibly move the crack initiation location to the bond line between the coating and the substrate. As such, it is important to characterize the fatigue behavior of the microstructures under different loading and environmental conditions. Hence, the investigation of fatigue degradation mechanisms of thin films is linked to the reliability concerns. Particularly, extreme stress gradients and stress ratio can occur for notched and unnotched components in bending mode. The geometry and the presence of extreme stress gradient under different stress amplitude necessitate characterizing the effect of extreme stress gradients and stress ratios on microstructurallysmall crack growth behavior to address the major reliability concerns for the thin film applications. The complex behavior of short cracks is due to less crack closure effects in short cracks as well as the interaction with the surrounding microstructural features in the materials such as grain boundaries, precipitates, inclusions, and phase boundaries. In addition to the experimental studies, finite element analysis has been employed to evaluate thermal stresses and temperature distribution in the coated energy harvesters during the fatigue test. This paper reviews the state-of-the-art in fabrication and characterization in flexible energy harvesters. The aim of this literature survey is to promote creation, development and application of novel experimental approaches to answer major and currently open questions on short fatigue mechanism of microstructural materials and also to provide a deeper understanding of mechanics of coated materials.
Weighted Rail Network Topological Analysis by Waybill Commodity Volumes
Authors: Mao Yujie , Elsibaie Sherief , Ayyub Bilal M. , Elsibaie Magdy , Omar Tarek , McClure Karen 
Published: February 2023

Abstract
This paper examines the topology of railroad networks using weight factors based on network topological attributes, such as commodity volumes transported; therefore, offering additional insights for enhancing freight rail networks and informing planning and operational decisions. The method proposed in this paper uses connectedness efficiency for network performance by considering node and link weights based on origination, termination, and interchange commodity volumes. These volume-based weights are designed to enable mixed units through normalizations. This paper uses freight traffic1 and associated volumes of goods moved as attributes to analyze the topology of an aggregate U.S. national railroad network as a case study. Following the topology of the aggregate network, freight data associated with U. S. counties are assigned to the nearest nodes in the network, and used to calculate node weights. After the assignment of node weights, connectedness efficiency was computed as a primary measure to assess the network for both unweighted and weighted cases with weights node for comparison purposes. It can be used for modeling network resilience at a topological level. In addition, the criticality of nodes and links were assessed reflecting the impact on network efficiency with a single node or single link loss or disability. Quarterly and annual waybill data were examined to assess seasonal changes and influences.
Damage Compensation and Strain Correction in Piezocomposite Laminates
Authors: Conaghan Grant , Payne Nicholas 
Published: February 2023

Abstract
Piezocomposites are composite materials composed of constituents that possess piezoelectric properties, by which an applied electric field induces a mechanical strain in the material. A common form of composite material is a laminated structure composed of numerous layers, or laminae, with embedded reinforcements whose orientation varies from layer to layer to create desired apparent mechanical properties at a larger scale. Composite laminates that are exposed to excessive loading above a critical threshold can experience damage in one or more laminae that will decrease the overall stiffness and load carrying capacity of the structure. In the case of a piezocomposite laminate in a damaged state, the application of electric fields to the laminate as a whole, or on an individual lamina basis, can compensate for the damage sustained and correct both the strain and degraded stiffness to pre-damaged values given the proper choice of electric field function. A methodology for determining the proper field function to compensate for the damage is derived and demonstrated in this paper.
First, piezoelectric homogenized properties at the lamina level are first derived using the Law of Mixtures with micromechanical subregions and shown to share the same form as hygrothermal coefficients. The mechanics of the laminate are treated using Classical Laminate Theory framework where the structure is conceptualized as a thin plate form factor whose deformation is described by a set of midplane strains and midplane curvatures which are uniform over the entire plate and all deformed material coordinates vary linearly through the plate thickness consistent with Kirchhoff-Love plate theory. Then, the method for compensating for the loss in stiffness and increase in strain from the occurrence of damage is established by equating the plate strain tensor in the damaged state with that of an equivalent undamaged state and solving for the necessary applied electric field.
The implications of fabricating a structure with a single field through the entire plate, or discretized into multiple fields with unique values is explored and solutions for each presented.
In the multi-field case, the system of equations has the mathematical property of being under-determined for any system with more than 6 discrete fields, so the least norm solution is employed. Several loading cases are examined, and the damage compensation solution is demonstrated to match the response of an equivalent laminate without damage behavior. The compensation method is agnostic to the type of damage model used on the micromechanical or lamina level and as such is generally applicable to any composite laminate that can be defined within Classical Laminate Theory. This methodology is applicable to devices which must maintain specific mechanical responses and can be applied to the design of active piezocomposite systems that auto-detect and correct for lamina damage.
Heat Transfer Performance Evaluation of PEMFC With Diamond-Shaped Staggered Cooling Channel
Authors: Mughal Pirbux , He Yadong , Luhur Ramzan 
Published: February 2023

Abstract
The fossil fuel depletion and environmental pollution are global challenges. Hydrogen is one of the most abundant elements on earth. Recently, scientists and researchers are investigating water splitting to produce oxy-hydrogen for internal combustion engines. Several studies have been published where hydrogen was used to generate electricity. The proton exchange membrane fuel cell (PEMFC) is an alternative energy resource for future electric vehicles. The reaction of PEMFC includes hydrogen molecules splitting as hydrogen ions and electrons on the anode whereas proton meet with oxygen and electrons and form water and release heat on the cathode. There are several processes involved in heat generation in PEMFC such as resistance in current flow, entropic heat reaction, and irreversibility of the electrochemical reactions. The generated heat in PEMFC is removed through cooling channels. The heat transfer rate depends on thermal properties. The design of the such as polymer electrolyte membrane, catalyst layer, gas diffusion layer, and electrodes have different thermal properties which influence heat transfer. Proper thermal management is critical part of PEMFC operation. Because the efficiency of PEMFC depends on heat loss in-between critical range. In this study, a numerical approach is used to investigate heat transfer performance of a (PEMFC) cooling channel. The heat transfer rate, convective heat transfer coefficient, temperature distribution and pressure drop were evaluated in this work. All these results were carried out on, 0.2, 0.4, 0.6 0.8 and 1 kg/s of mass flow rate of coolant in the PEMFC cooling channel. Ansys Fluent is used for the numerical investigation. The diamond shape extended staggered pattern cooling channel were used in fuel cell for distributed flow. In this study, 2mm transverse pitch whereas 1mm, 1.5 mm and 2 mm longitudinal pitch with diamond shape extended in PEMFC cooling channel are used. However, design of experiments method was used to sort optimum results. The results reveal the extended staggered cooling channel improve heat transfer performance, 2mm and 1.5 mm transverse and longitudinal pitch respectively gave better heat transfer results and slightly higher pressure drops than 2mm pitch. Turbulence kinetic increases with decreasing transverse pitch and flow distribution improved with longitudinal pitch.
A Sustainable Approach to Designing a Bird Wing Prosthesis
Authors: Mukhamedjanova Aleese , Lundemo Trinity , Shady Sally 
Published: February 2023

Abstract
Raptors are some of the most threatened birds around the globe, with 18% of raptor species being in danger of extinction and 52% with declining populations. Many birds that are brought into rescue centers with a complicated wing injury must be euthanized. In very rare cases, such birds may alternatively have their wing amputated, often leaving them grounded and unbalanced. Many raptors are endangered, and as predators at the top of their food chains, the loss of these birds from the ecosystem leads to severe environmental upheavals that can affect the daily lives of people. Thus, euthanasia and rehabilitation are not sustainable solutions with regards to raptors with broken wings. Alternatively, this study proposes a transhumeral prosthetic wing that can allow amputee raptors to potentially fly again. A series of biomechanical analyses were performed along with a material analysis to create a three-dimensional model of a prosthetic wing. An analysis of forces and flapping gait during flight was conducted, which, to our knowledge, has not previously been done. Environmentally friendly polymers that consist of PLA and beta-keratin were assessed to determine feasibility in a wing prosthesis. A finite element analysis (FEA) was performed and revealed that the sustainable PLA and beta-keratin material has sufficient mechanical properties to withstand the kinetics of extended flight, improving the model’s structural integrity.
Performance Characteristics of PMDC Motor of Small-Scale Experimental Ocean Current Turbine
Authors: Rouhi Shahab , Xiros Nikolaos , Aktosun Erdem , VanZwieten James , Sultan Cornel , Ioup Juliette , Sadeqi Setare 
Published: February 2023

Abstract
A comprehensive numerical model was developed to address the performance of a permanent magnet direct current (PMDC) motor which is employed as a small-scale three-bladed horizontal axis ocean current turbine. This numerical model development is presented along with a comparison to experimental data to quantify the motor performance. The proposed experimental design is discussed in detail. Due to the nature of the ocean current turbine, it is required to run it first by applying input power, subsequently to be governed by hydrokinetic energy. Thus, a detailed performance of the PMDC motor is essential when it runs as a motor and generator. Based on our preliminary work, the angular speed of the small-scale turbine is less than 500 rpm. Thus, a combination of the PMDC motor and a planetary gearhead is used to fulfill this low-speed requirement. The gearhead is driven in reverse when operating as a generator which leads to poor efficiency. This efficiency is experimentally derived to be 47.8% at maximum speed of 479.4 rpm at 12V.
Benchmark Study of XFTA and SCRAM Fault Tree Solvers Using Synthetically Generated Fault Trees Models
Authors: Aras Egemen M. , Farag Asmaa S. , Earthperson Arjun , Diaconeasa Mihai A. 
Published: February 2023

Abstract
The development of the nuclear industry’s Probabilistic Risk Assessment (PRA) has significantly contributed to the design, reliability, and safety of nuclear power plants (NPP). Today, PRAs form integration in all nuclear power plant development stages, including design, licensing, operation, maintenance, and decommissioning. Many legacy PRA tools have been used in the nuclear field; however, more powerful tools are needed to cope with the rapid development of the nuclear industry and NPP designs. These tools are now required to analyze new aspects of the plants that were never envisioned before, and more computational resources are needed.
This study uses synthetically generated fault trees of various sizes and specifications to benchmark fault tree solvers; XFTA version 1.3.1 and SCRAM version 0.16.2. The analysis is performed in two steps. The first step is to compare the probabilities, minimal cut sets, and importance factors. The second step is measuring CPU time, wall time, and the memory usage of each engine for benchmarking. The result for the first step for the same configuration is the same for each calculation engine. Overall, XFTA can complete most of the given runs in a shorter time with less memory usage than SCRAM. All computations and measurements are done on a specified computer.
Finite Element Simulation and Analysis of Drop Tests to Improve the Mechanical Design of a Handheld QSTM Medical Device
Authors: Bhattacharjee Abhinaba , Loghmani Terry , Anwar Sohel 
Published: February 2023

Abstract
The structural integrity of an electro-mechanical assembly significantly determines the robustness of the design and durability of a product. Handheld portable medical devices require more attention on their compactness and packaging to ensure design fidelity for manufacturing and avoid permanent damages during inevitable drops or rough handling in a clinical setup. Hence, a finite element analysis is performed for quality conservation, risk assessment, and design failure mode error analysis. This paper investigates the mechanical impacts of drop tests on a handheld portable mechatronic medical device used to quantify real-time dispersive force-motion patterns in the form of Quantifiable Soft Tissue Manipulation (QSTM) for therapeutic massage, clinical manual therapy, and pain level assessments against neuro-musculoskeletal conditions. Structural analysis of the handheld medical device’s mechanical design and assembly has been performed by finite element methods to identify parts of assembly susceptible to maximum stress and deformation during static impact loading and impacts of collisions at drop test simulations. The CAD model of the medical device is illustrated and evaluated with material modeling and structural analysis to distinguish weaker supports and further reinforce them with modified design iterations. This analysis enabled a revised design of the QSTM device which showed significant reduction in stresses and deformations as compared to the baseline design.
Electrical Characteristics of the Oxyfuel Preheat Flame: 3D Computational Model Subject to Electric Bias Voltages
Authors: Rahman S. M. Mahbobur , Warrier Rohith , Untaroiu Alexandrina , Martin Christopher R. 
Published: February 2023

Abstract
A three-dimensional (3D) computational model is presented in this paper that illustrates the detailed electrical characteristics, and the current-voltage (i-v) relationship throughout the preheating process of premixed methane-oxygen oxyfuel cutting flame subject to electric bias voltages. As such, the equations describing combustion, electrochemical transport for charged species, and potential are solved through a commercially available finite-volume Computational Fluid Dynamics (CFD) code. The reactions of the methane-oxygen (CH4 – O2) flame were combined with a reduced mechanism, and additional ionization reactions that generate three chemi-ions, H3O+, HCO+, and e−, to describe the chemistry of ions in flames. The electrical characteristics such as ion migrations and ion distributions are investigated for a range of electric potential, V ∈ [−5V, +5V]. Since the physical flame is comprised of twelve Bunsen-like conical flame, inclusion of the third dimension imparts the resolution of fluid mechanics and the interaction among the individual cones. It was concluded that charged ‘sheaths’ are formed at both torch and workpiece surfaces, subsequently forming three distinct regimes in the i-v relationship. The i-v characteristics obtained out of the current study have been compared to the previous experimental and two-dimensional (2D) computational model for premixed flame. In this way, the overall model generates a better understanding of the physical behavior of the oxyfuel cutting flames, along with a more validated i-v characteristics. Such understanding might provide critical information towards achieving an autonomous oxyfuel cutting process.
Impact of the Tip Clearance and the Inflow Nozzle Shape on the Performance of Low-Pressure Axial Fans
Authors: Fritsche Manuel , Epple Philipp , Delgado Antonio 
Published: February 2023

Abstract
Low-pressure axial fans have a very wide range of applications in the field of heating, ventilation and air conditioning as well as refrigeration (HVAC&R). Due to stricter legal requirements, increasingly higher fan efficiencies are required. Due to legal regulations, more efficient machines are becoming increasingly important. A small gap, the so-called tip clearance, is necessary between the rotating impeller and the stationary shroud due to manufacturing tolerances and structural-mechanical expansion as well as thermal expansion. However, this tip clearance has a strong impact on the performance of the fan. Due to the gap between the blade tip and the shroud wall, a circulation volume flow rate occurs depending on the operating point. This can have a strong influence on the inflow condition, for instance a standing vortex can develop at lower volume flow rates in front of the impeller at the tip region. Overall, this affects the operating behavior and the performance characteristics, i.e. the integral pressure characteristics as well as the efficiency characteristics. In the present investigation, an axial impeller was designed and optimized for this purpose. The impeller blades were designed as flat sheet metal blades with a constant thickness. This axial impeller was modeled with ANSYS Blade Modeler and simulated with the commercial CFD solver ANSYS CFX.
In the first simulation study, the tip clearance was varied and analyzed. As a reference case the impeller was simulated also with no gap. Since the tip clearance effectively makes the blade shorter, the influence of the shortened blades was compensated considering the similarity theory of fans. Second, the shape of the inflow nozzle, i.e. the radius and the length, was varied, simulated and evaluated.
In order to determine the influence of the tip clearance and the shape of the inflow nozzle, the integral characteristics such as the pressure characteristic and the efficiency characteristic were compared. In addition, the flow field around the blade tip as well as in the inflow nozzle were analyzed and areas of flow detachment were evaluated. For the inflow nozzle the meridian and circumferential velocity was evaluated and compared in different sections in the inflow nozzle. Finally, the study showed that for the present application of the low-pressure axial fan, the tip clearance has a significant impact on the performance of the fan. An optimal compromise between manufacturing costs and acceptable losses due to tip clearance was sought. The method and the results are presented and discussed in detail.
Reliability and Safety Assessment of Passive Safety Systems Through Coupling of Fault Tree Analysis and Artificial Neural Network
Authors: Khosravi Babadi Parham , Lu Lixuan 
Published: February 2023

Abstract
Small Modular Reactors (SMRs) have attracted much attention in recent years, and they could play a significant role in the future of energy supply and the nuclear industry. Many factors have contributed to the advancement of SMRs, including their affordability and zero greenhouse gas emissions. However, the most significant advantage associated with SMRs is their increased safety level, which has been achieved by introducing a wide range of new design features. Despite the diversity of design techniques, a similar set of design principles, such as Passive Safety Systems (PSSs), has been adopted to improve plant safety and robustness, eliminate design vulnerabilities, minimize accident likelihood, and mitigate accident effects. Reliability and safety evaluation of PSSs are crucial from the design phase to achieve these objectives. Probabilistic Safety Assessment (PSA) is a well-known methodology for analyzing risk levels associated with safety-critical systems in many industries, such as the aerospace, oil and gas, and nuclear industries. Probabilistic safety assessment utilizes the combination of Event Tree (ET) and Fault Tree (FT) techniques to estimate risks associated with certain undesired top events, such as core meltdown in the nuclear industry. Although PSA offers a range of advantages for safety assessment compared with traditional deterministic risk analysis technology, it also has some limitations. There are still many challenges associated with dynamic PSA analysis due to the demand for computational power for oversized FTs and ETs. Moreover, the final assessment result is prone to a significant uncertainty level due to human-related errors.
Some of the challenges associated with PSA might be alleviated by Artificial Neural Networks (ANNs), as ANNs address the limitations of PSA, such as adaptive capacity, learning ability, and real-time calculation, which are challenging for dynamic process systems. Apart from ANNs, Bayesian Networks (BNs) are used to establish the collection of stochastic processes and their conditional dependencies through graphical connections. Bayesian Network is a graph layout that models accident scenarios and various real-world problems. This paper investigates the application of artificial intelligence (Deep Learning (DL)) to enhance FT analysis through the conversion of FT and ANN models.
The potentiality of extending this technique to analyze the reliability and safety of PSSs in SMRs is examined. In SMRs, natural circulation has a low driving force, and PSSs are easily manipulated by system variables such as heat loss, flow friction, and oxidation, leading to system instability and jeopardizing the system’s safety. As a result, FT analysis is inadequate to capture these effects in real-time to analyze the reliability and safety of PSSs. This paper demonstrates that the introduction of ANN could help address some of these limitations.