bluuebunny/crossref_metadata_2025_split huggingface dataset:
Experimental Study of the Nano-Fin Effect (nFE) During Thin Film Evaporation From Nanopores in Anodic Aluminum Oxide (AAO) Membrane Substrates Integrated With Nano-Thermocouple / Thin Film Thermocouple (TFT) Array
Authors: Shafer Julie , Lee Jonghyun , Thyagarajan Ashok , Banerjee Debjyoti 
Published: February 2023

Abstract
Recent advances in micro/nano-fabrication has enabled the deployment of nanostructured surfaces, nanochannels, and nanoporous membranes for development of new generation thermal management devices with remarkable potential for heat transfer enhancement. Anomalous heat transfer has been reported in studies involving heaters with nanostructured surfaces. For example, nanofins with lower thermal conductivity values can cause higher levels of enhancement in heat flux values, especially during phase change (such as for boiling on heaters with nanostructured surfaces). In addition, confinement of fluid in nanopores can also result in anomalous properties. This is manifest in anomalous production curves during hydraulic fracturing operations in oil and gas applications. A transport model that resolves these conundrums is termed as the “nanoFin Effect (nFE)”.
nFE is governed by interfacial phenomena, i.e., the formation of thermal impedances in parallel circuit configuration, consisting of: (a) interfacial thermal resistance (also known as “Kapitza resistance”); (b) thermal capacitor; and (c) thermal diode (that form at the interface between each nanoparticle and the surface adsorbed thin-film of solvent molecules). nFE (i.e., primarily the interfacial thermal diode effect) also leads to preferential trapping of ions on the surface adsorbed thin film of solvent molecules leading to very high concentration gradients causing drastic reduction in corrosion.
The motivation of this study was to explore nFE during thin film evaporation from nanopores. The methods used in this study include mounting a nano-thermocouple array (also termed as Thin Film Thermocouples or “TFT”) on a hot plate and observing the transient response recorded by the TFT array when a small liquid droplet (of fixed mass or volume) is dispensed on to an anisotropic AAO membrane containing nanopores. In this study, two different pore sizes were explored: 200 nm and 10 nm. The experiments were performed using isopropyl alcohol (IPA) droplets for four different temperature settings of the heated membrane (containing the nanopores).
Introducing Integral Engineering Skillsets to the Diverse Population of Underrepresented Students at the University of the District of Columbia via the NASA Human Exploration Rover Challenge
Authors: Harrigan Voss , Xu Jiajun , Haghani Sasan 
Published: February 2023

Abstract
The University of the District of Columbia (UDC), the only public university in the nation’s capital and a land-grant university, has been participating in the NASA Human Exploration Rover Challenge for the past several years. The teams are asked to design and fabricate a two-person human-powered rover capable of traversing a course designed by NASA to simulate various terrain. The rover requires a significant redesign each year; therefore, these disciplinary benefits and opportunities encouraged the students to form a team in 2022. The team leveraged UDC’s new NASA-funded Center for Advanced Manufacturing in Space Technology & Applied Research (CAM-STAR) and its research facilities to design the rover. This paper introduces the rover competition for 2022 and the UDC team’s new designs using advanced and additive manufacturing. Also, the skill sets learned by the diverse population of the team members are discussed, along with critical engineering techniques using various forms of engineering.
Shape Modeling of Potential Sink Marks for Aesthetic Design of Plastic Parts
Authors: Inui Masatomo , Umezu Nobuyuki 
Published: February 2023

Abstract
Shallow depressions, called sink marks, may form on the surface of plastic parts produced by injection molding. These depressions are caused by partial differences in the amount of shrinkage of plastic parts during the solidification process. The appearance of such depressions in the exterior of the product degrade its aesthetic quality. In this study, we propose a shape modeling technique of possible sink marks. The input data of the method is a polyhedral model of a part. This model is transformed to another polyhedral model of the same shape and whose surface polygons have a sufficiently small size. For each vertex of the part, the amount of shrinkage is determined using the result of the thickness analysis at the vertex of the model. The position of the vertex is then modified according to the shrinkage value to obtain a solid model with shallow depressions on its surface. By properly visualizing the model using the computer graphics technique, it becomes possible for the designer to evaluate the influence of sink marks on the part appearance.
A Closed Loop Pressure Assisted Boiling Point (PABP) Control System for Thermal Fusion Bonding of Thermoplastics
Authors: Dathathreya Kavya , Park Daniel S. , Park Taehyun , Soper Steven A. , Murphy Michael C. 
Published: February 2023

Abstract
An innovative method of thermal fusion bonding (TFB) using a pressure assisted boiling point (PABP) control system was characterized to determine the optimum parameters for bonding thermoplastic components containing microchannels and thin cover sheets. The PABP TFB system enables precise control of the temperature and the pressure boundary conditions by immersing a bag containing the components being bonded in boiling water and varying the vapor pressure. The original system used a human operator to manually adjust a pressure relief valve and maintain the system temperature, which introduces time delays. A closed loop control system was developed to automatically control the temperature in the pressure vessel. Test structure geometries containing microchannels of two depths, 5μm and 10μm, and four different aspect ratios were designed: 1:10, 1:50, 1:100, and 1:200. Microchannels were hot embossed in polymethyl methacrylate (PMMA) using micro-milled brass mold inserts. Results of bonding with the closed loop systems were evaluated. Mean rupture pressures decreased with increasing AR and were higher for shallower channels for the automated closed loop system. For a given aspect ratio, the rupture pressures ranged from 5%–19% higher for 5 mm channels and increased by 5%–10% in 10 mm channels with the automated closed loop system.
Actively Controlled Magnetic Bearing System Using Compliant Mechanism
Authors: Chaudhary Vivek , Pandey Sameer , Khatait Jitendra P. , Mukherjee Sudipto 
Published: February 2023

Abstract
Rotors with speeds more than 20000 rpm, like Flywheel Energy Storage System (FESS), are fully or partially evacuated to reduce drag but have to be geometrically constrained except in the rotation axis. Magnetic bearings are preferred over a rolling element or journal bearings. The high-speed rotor is supported on active magnetic bearings. Though magnetic bearings with multi-axis support are possible, we look at building the support using desired passive compliance along five DOFs and one contactless support using a magnetic field with high stiffness at the set gap. A single DOF active magnetic bearing system is designed to precisely position a shaft along the longitudinal direction. The shaft is supported on a pair of compliant ortho-planar mechanisms at the two ends. The compliant structure is designed to provide bearing support along the radial directions. The position of the shaft along the longitudinal direction is actively controlled using the magnetic bearing system. A two-unit system based on magnetic attraction, one at either end, is designed. A candidate compliant ortho-planar mechanism is designed to support the shaft and fabricated using rapid prototyping. Stresses and bearing stiffness along different axes are calculated and analyzed using FEM. The 3D printed part was used for visualization and tested for compliance in the active magnetic bearing direction. The active magnetic bearing system is modeled. The controller will be optimized for disturbance rejection and minimize excursion around a desired axial location. The developed setup can be used to study and develop multi-axis AMB for high-speed rotating applications.
Assessment of LIDAR Imaging Systems for Autonomous Vehicles in Adverse Weather and Under Dynamic Conditions
Authors: Abdo Jamil , Russell Luke N. , Mills James , Frailey Taylor D. , Chen Genshe 
Published: February 2023

Abstract
One of the main challenges for the safety validation of autonomous driving vehicles lies in the influence of weather phenomena. As each of the main sensors, namely LIDAR, radar, and cameras increases its sensitivity to detect smaller objects faster and hence be able to drive autonomously at higher speeds, the possible influence of environmental perturbations on their perception increases. Those perturbations could cause false positives, confuse self-calibration algorithms and reduce the sensor range. On the other hand, they could constitute a source of valuable information if the dependencies are known and properly characterized to better evaluate and predict road conditions or adapt its operation mode. The main purpose of this work is to evaluate the impact of adverse weather conditions mainly heavy snow on LIDAR sensor performance in dynamic conditions, i.e. moving sensors and moving-target scenarios.
A Dynamic Mode Decomposition Method for Modal Analysis of Human Brain Diagnosis
Authors: Fereydoonpour Mehran , Mclean Jayse , Ziejewski Mariusz , Karami Ghodrat 
Published: February 2023

Abstract
Modal analysis is a strong tool of mechanical diagnosis and behavior of bodies and structures. The method can be employed for human head as a body to recognize its natural frequencies. Brain injury can be destructive around the brain’s resonant frequencies with the external applied loading and motion. Vibrations due to an assault on the head are sent throughout the brain under impacts or high motions. These waves propagate and attenuate at different rates within the brain depending on the magnitude and direction of the impact loading or motion. By conducting modal analysis of the brain and identifying its resonant frequencies we can measure the risk of injury and reduce or possibly even eliminate vibrations in these frequency ranges. This paper employs a finite elements method to simulate the impacts for different impact angles on a human head. A numerical technique based on dynamic mode decomposition (DMD) will be used to extract the modal properties for the brain tissue in regions near the corpus callosum and brain stem. The study aims to identify a frequency range in which the brain is more susceptible to vibration with the end goal of better understanding the brain in the frequency domain and preventing future TBIs. Three modal frequencies were identified with frequency ranges of 44–68Hz, 68–155Hz, and 114–299Hz. It is found that the impact angle, displacement direction, and region of the brain have a significant impact on the modal response of brain tissue during any impact. The study also provides insight into the effects of impact angle, displacement direction, and different regions of the brain.
Physics-Based Filament Adhesion Modeling in Fused Filament Fabrication
Authors: Aniyambeth Shreyas , Malekar Deepak , Özel Tuğrul 
Published: February 2023

Abstract
Material extrusion processes such as fused filament fabrication (FFF) are among the most widely used additive manufacturing (AM) technologies. The fused filament fabrication process consists of simultaneously feeding and melting a filament of polymer material through a computer-controlled liquefier. The material then flows through the nozzle under pressure, which must fully solidify while remaining in extruded shape. Deposited layers are fused together as the melted material quickly solidifies to form layers of a solid 3-D object. The key elements are material feed mechanism, liquefier, print nozzle, build surface and environment. The general applications are production of prototypes during product development phase, short series production runs where tooling cost is high, and parts with high geometrical complexity which cannot be produced by means of conventional manufacturing. Often, time evolution of temperature as recorded by thermography and adhesion behavior of filament are investigated by considering main process parameters, such as filament dimensions and material, sequence of deposition and environment temperature. In this paper, thermal behavior of material extrusion and filament adhesion is analyzed.
Further Insights Into the Timoshenko-Ehrenfest Beam Theory
Authors: Banerjee J. Ranjan , Kennedy David , Elishakoff Isaac 
Published: February 2023

Abstract
In this paper, the theory of a Timoshenko-Ehrenfest beam is revisited and given a new perspective with particular emphasis on the relative significances of the parameters underlying the theory. The investigation is intended to broaden the scope and applicability of the theory. It has been shown that the two parameters that characterise the Timoshenko-Ehrenfest beam theory, namely the rotary inertia and the shear deformation, can be related and hence they can be combined into one parameter when predicting the beam’s free vibration behaviour. A theoretical proof is given that explains why the effect of the shear deformation on the free vibration behaviour of a Timoshenko-Ehrenfest beam for any boundary condition will be always more pronounced than that of the rotary inertia. The range of applicability of the Timoshenko-Ehrenfest beam theory for realistic problems is demonstrated by a set of new curves, which provide considerable insights into the theory.
Review of Thermal-Hydraulic Modeling Methods of Printed Circuit Steam Generators for Small Modular Reactors
Authors: Cho So-Bin , Wang Chengqi , Allen Todd , Sun Xiaodong 
Published: February 2023

Abstract
Small Modular Reactors (SMRs) are promising to address a wide range of energy needs. Steam generator (SG) is usually one of the largest and most expensive components in a nuclear energy system. Therefore, the overall economics of an SMR plant employing a steam Rankine cycle is strongly influenced by its SG selection. Previous case studies conducted at the Idaho National Laboratory, assessing the techno-economic performance of advanced reactors for water desalination and hydrogen production, have mostly focused on reactor system options with conventional U-tube SGs or helical-coil SGs. Incorporating a two-phase Printed Circuit Heat Exchanger (PCHE) as a SG, termed a Printed Circuit Steam Generator (PCSG), has the potential to further improve the plant economics by significantly reducing the system volume through its enhanced compactness. This paper summarizes an ongoing effort to access the thermal-hydraulic performance of a PCSG for SMRs and establishes a reference model using the correlations that have been adopted and benchmarked by the latest PCSG modeling study. Our results suggest that using a one-dimensional (1-D) code for outlet temperature calculations (i.e., the hot and cold sides) and a pressure drop calculation for the single-phase flow (i.e., the hot side) can be as accurate as those in the three-dimensional (3-D) code used in Ocampo’s study in 2020 (typically less than 0.5 % and 7 % differences, respectively). However, it is noted that the calculated pressure drop for the cold side shows as high as 4 % and 25 % of discrepancies between the correlations and the dimension of simulation (i.e., 1-D and 3-D), respectively. The identified ranges of the uncertainties from this inter-model comparison would support the development of PCSG designs for SMRs while urging researchers to develop validated thermal-hydraulic models for PCSG.
Adsorption of Hydrogen Isotopes on Novel Nanomaterials
Authors: Polat Suheyl , Stinebaugh Aaron , Park Jungkyu 
Published: February 2023

Abstract
We investigated the possibility of using various novel nanostructured carbon for control of hydrogen isotopes by exploring the adsorption, reflection, and penetration of hydrogen isotopes using molecular dynamics. Nanometer sized allotropes of nano-carbons have completely changed the research trend in carbon materials, and opened numerous exciting possibilities in many applications. Researchers started to pay attention to carbon nanomaterials when Fullerene C60 was discovered in 1985. The discovery of carbon nanotubes in 1991 and the first isolation of single layer of graphene from graphite in 2004 have encouraged researchers to measure the exciting thermal, electrical, and mechanical properties of these carbon nanomaterials computationally and experimentally. In the present research, we investigate graphene layers and nanostructured carbons with random configurations. The REBO and AIREBO potential are used alongside LAMMPS to simulate tritium interactions with sheets of graphene. Custom MATLAB codes were used to create the graphene structure as well as randomly distribute 100 tritium atoms along a plane above and parallel to the graphene sheet. The tritium atoms are held in place while the graphene sheets undergo multiple stages of equilibration. The velocities of tritium atoms are selected so that incident energies may be 0.1, 0.2, 0.5, 1, 2, 5, 10, 20, 50, 100, 200, or 500 eV during a single simulation. Reflection is shown to be the dominant interaction at low incident energy. Adsorption rates increase with increasing incident energy until energies reach 5 eV. After 5 eV, adsorption rates decrease as incident energy increases. At incident energies greater than 5 eV, adsorption rates increase with the number of graphene layers. At low incident energies (&lt; 1 eV), no isotopic effects on interactions are observed since the predominant interaction is derived from the force of π electrons. Simulations were performed with different incident angles of tritium. Adsorption rates are always the highest when tritium atoms travel vertically towards graphene (θ = 0°) while they are the lowest when the angle is the largest (θ = 60°) with only a few exceptions (5 eV and 10 eV). AIREBO potential shows a significant difference in adsorption of tritium on graphene from REBO potential. AIREBO potential consistently showed lower adsorption rates and higher reflection rates when compared to REBO potential. The results obtained in this research study will be used to develop novel nanomaterials that can be employed for tritium control.
Fast and Robust Damage Imaging With a Cascaded Deep Learning Technique
Authors: Tong Junkai , Lin Min , Li Jian , Wang Xiaocen , Chu Guoan , Liu Yang 
Published: February 2023

Abstract
Quantitatively measuring the health status of mechanical structures is a long-standing challenge in industrial fields. For plate structure inspection in tank and pressure vessels, traditional techniques using point by point scan with probes are tedious and time-consuming. Although algorithms like full waveform inversion (FWI) and diffraction tomography (DT) provide solutions to the problems, those methods are slow and suffer from convergence problems. In this article, we provided an effective damage imaging technique using dispersive A0 mode Lamb guided wave and an inversion algorithm called DLIS. The proposed algorithm adopts convolutional neural network (CNN) as first iteration to provide a fast and low-resolution background, and further optimizes the inversion results with descent direction matrix. In this way, the nonlinearity of the problem is effectively decomposed and yields better results. To test the robustness of the proposed method, we generated 1000 samples consists of corrosion defects with various sizes and shapes using 2D acoustic wave modeling. The inversion results prove the feasibility of our approach in plate heath monitoring and inspections. Note that this method also has full potential to be applied in the fast inspection of plates made of composite materials, pipes, geophysical prospecting and medical imaging because all these inverse problems share similar physics.
The Potential and Limitations of Using Geothermal-Sourced Chiller Plants to Eliminate Cooling Towers
Authors: Farag Ahmed , Ahmed Mahmoud , Ookawara Shinichi , Emam Mohamed 
Published: February 2023

Abstract
The purpose of this research is to evaluate the feasibility and performance of a vertical ground source refrigeration system for cooling a typical 7300 m2 office building after replacing cooling towers used for condenser cooling with three different designs of ground heat exchangers. To that end, a three-dimensional, transient, and conjugated finite volume model is developed and simulated to compare the thermo-hydraulic performance of the traditional single U-tube with that of double U-shaped, and spiral-shaped ground heat exchangers at different flow rates. Based on the results, spiral shaped ground heat exchangers outperform other designs, as seen by better heat exchange rates between the fluid and the soil, which translates to a greater temperature reduction of the cooling water. This improvement not only allows for using smaller number of boreholes which saves the construction costs compared to other designs, but it also improves the coefficient of performance of the system by significantly lowering the cooling water temperature flowing back to the condenser when compared to the conventional cooling tower. This approach also eliminates cooling tower water consumption (saves about 14,500 L/day), tower noise, annual maintenance expenses, and costs for periodical cooling tower replacement. The presented findings make a significant contribution to society by offering innovative and sustainable solutions for cost reduction, environmental conservation, and energy efficiency.
Reduced Theories for Thick Shells
Authors: De Rosa Maria Anna , Lippiello Maria , Elishakoff Isaac 
Published: February 2023

Abstract
The present paper is part of a previous research, started in [1] with the proposal to neglect an energetic term in the dynamic analysis of Timoshenko-Ehrenfest beams. The resulting reduced theory turned out to be both simpler and more reliable than the complete, classical, approach. Whereas the original idea was heuristically justified, a sounder variationally consistent theory has been proposed in [2] and, later on, in [3]. Following the suggestion offered in [1–3], we initially describe the classical theory, and subsequently we propose two alternative hypotheses that lead to two differences aspects of the energy terms. Applying the variational approach, two new different boundary problems are deduced, which are direct generalizations of what was done previously. Both theories can be easily specialized for beams and plates. In addition, the theory is also specialized for the case of cylindrical shell.
Investigation of Water Effects on Surface Acoustic Wave Transmission
Authors: Bo Luyu , Li Jiali , Zhang Xinyu , Li Teng , Tian Zhenhua 
Published: February 2023

Abstract
Corrosion is a typical damage type in metallic structures. Free water on metallic structures can gradually lead to corrosion damage. In this study, we investigated free water sensing based on surface acoustic waves (SAWs). The fabricated SAW device consists of two interdigital transducers (IDTs) in a pitch-catch configuration on a lithium niobate (LiNbO3) piezoelectric substrate. Finite element simulations of SAWs generated by IDTs and SAW-droplet interaction were performed. To unveil the effects of a water droplet on SAWs and understand the mechanism of our SAW device, we simulated multiple cases with different volumes of water droplets. The simulation results show that the transmission amplitude gradually decreases with the water volume increase. A proof-of-concept experiment was performed by using a fabricated SAW device to detect a water droplet on the substrate surface. The experimental results show a similar trend as that of the finite element simulations.