bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Ultrasonic Testing Approach for In-Situ Monitoring of the Fused Deposition Modeling Process
Authors: Pozhanka Mariya , Flores Celeste , Crosswhite Caleb , Stevens Zane , Vig Aidan , Trudell Noah , Zagrai Andrei 
Published: February 2024

Abstract
Additive manufacturing (AM) is a modern fast-growing technology which allows for the fabrication of parts not possible to fabricate with conventional machining techniques. However, in contrast to conventional manufacturing, AM process often results in products with broad variation of properties. Individual parameters of the printing process and their combinations influence final mechanical properties of the printed material and may result in the internal defects. Therefore, inadequate selection of printing parameters may lead to defects formation, undesirable material properties or to a failure during AM process, and hence wasting time and materials.
Nondestructive evaluation (NDE) techniques could be used to improve the trustworthiness and reliability of the manufacturing process. In this contribution, the approach for enabling real-time NDE for monitoring the material properties of the printed part is suggested. The approach is based on adjustment of the printing process parameters depending on elastic properties monitoring of the material printed. There approach requires collecting the database of dependencies of printing process parameters and elastic properties of the material. Three printing parameters were chosen for this purpose: layer thickness, nozzle temperature, and nozzle speed. Virtual engineering workbench with a visual programming language LabVIEW was proposed. The approach allows for capturing the real-time in-situ sensor data and comparing it to the reference data arrays reflecting the influence of the printing process parameters. Consequently, a direct modification of the parameters during the printing process could be achieved based on the real-time sensor data.
Developing a Low-Cost Instrumented Heat Transfer Apparatus for Measuring Thermal Conductivity Using Steady-State Methods
Authors: Bunt Brandon , Wright Kamau , Davis Benjamin 
Published: February 2024

Abstract
In the present study, a linear heat conduction module (LHCM) was developed and used to measure the thermal conductivity of brass at steady-state. Off-the-shelf components were used to keep costs significantly lower than commercially available LHCM’s. Initial tests show that the present apparatus can be used to accurately measure the thermal conductivity of Brass 360 within 3.79% of literature values. The system is intended for operation to test a range of materials, including solid and porous samples of thermally conductive materials, such as aluminum and brass, as well as less conductive materials. Models and supporting tests help to establish appropriate operating ranges for the LHCM system, while facilitating comparisons and recommendations for future testing of porous and composite media and lower conductivity materials.
The Role of Meditation in Stress Recovery and Performance: An EEG Study
Authors: Ahmed Mohammad H. , Kaya Mehmet , Taebi Amirtaha , Thibbotuwawa Gamage Peshala 
Published: February 2024

Abstract
This study aimed to investigate the effects of meditation on recovery time following a stressor and cognitive performance. Two sessions were performed in this study, one as a control without participants meditating prior to the stress task and one with meditation. EEG signals were recorded from 24 channels and processed using frequency domain analysis to measure power in various frequency bands. Participants for this pilot study were 10 healthy adults between the ages of 18 and 35. Reaction time and response accuracy were used as performance measures during the stressor with slower reaction times indicating lower levels of alertness. Brain activity prior to the stressor was compared with activity following the stress task, and the time needed to return to baseline was observed. The effect of meditation on recovery time and performance was analyzed and a gradual return to baseline values was observed. Recovery time varied among participants, with some taking longer than others to recover but no significant change was observed with meditation. Performance-wise, participants who meditated prior to the stressor had improved reaction time and accuracy when compared to the control group. The results suggest that interventions such as meditation or mindfulness practices may help individuals improve performance, but further research is needed to confirm these findings.
Printability Study of Short Electrospun Nanofiber-Hydrogel Composites
Authors: Yan Karen Chang , Desai Raahi , Griffin Tyler , Sood Taniya 
Published: February 2024

Abstract
Microfluidic devices have been developed for many biomedical applications owning to inherent advantages of miniaturization, integration, cost-effectiveness and high efficiency. Microfabrication-free technology has been used to fabricate microfluidic devices. Our group has developed a hydrogel printing system based on 3D printing technology that enables forming microchannels, which has a potential of incorporating electrospun (ES) fiber in the microchannel via the developed hydrogel printing system. Specifically, polycaprolactone (PCL) was selected owning to biocompatibility, low cost, and suitability of electrospinning. Gelatin was selected as the hydrogel material based on our previous study. Produced ES fiber membranes were plasma treated to increase hydrophilicity, and then shortened via cutting and blending. Microscopic image analysis was conducted to characterize the length and morphology of the short fibers. The shortened fibers subsequently were suspended in absolute ethanol and mixed with gelatin solution to form composite materials for printing. An initial screening method was applied to identify potential composites with varying concentration.
Characterization of Macromolecule Diffusion of Electrospun (ES) Fibers Embedded in Microfluidic Devices
Authors: Yan Karen Chang , Sood Taniya , Desai Raahi , Merritt Michael 
Published: February 2024

Abstract
Electrospun (ES) fibers made of biocompatible polymers have been used as scaffolds in tissue engineering to mimic the fibrous environment found in the extracellular matrix (ECM) of biological tissues. Bioactive macromolecules such as growth factors can be incorporated in the ES fibers via encapsulation and/or surface adsorption, and then released to the surrounding environment gradually via diffusion process. As the release rate is influenced by multitude parameters, it is of great importance to understand how macromolecules diffuse under static and dynamic conditions. Our group has developed a 3D printing based method to embed short fibers in microfluidic devices via hydrogel molding (HGM). Furthermore, fluorescence imaging techniques were developed to study and quantify the molecular transport phenomena. Image analysis was utilized to characterize diffusion behavior of macromolecules adsorbed on the surface of ES short fibers. 10w/v% polycaprolactone (PCL) acetone solution is used to electrospun fibers. The ES fibers are then processed and plasma treated to increase hydrophilicity. Fluourescieneisothiocyanate dextrane (FITC-dextran) with a molecular weight of 70kDa (FD70) is used as a model macromolecule. Samples of short ES fibers are submerged into 0.20 mg/ml FD70 solution for 24 hours and dried subsequently. Submersion studies are conducted for the fiber samples with FD70 adsorbed on the surface. Based on the relationship between the light intensity and the FD70 concentration, the FD70 concentration of submersion fluid is determined as a function of. Static submersion study was conducted for both PCL fiber membrane and short fibers. Experimental data suggested that short fiber samples showed faster diffusion and the FD70 concentration in the submersion fluid reached 0.05mg/ml at 15hours, while the results from the membrane sample showed 0 hours were needed. A dynamic test set up was also developed, which allows further study under various flow conditions.
Design and Fabrication of a Modular, Lightweight, and Portable Upper Limb Exoskeleton for Shoulder and Elbow
Authors: Lacuata Nathanael , O’Dell Brandon , John Anthony , Pelletier Cameron , Jefferson David , Lineberger Richard , Sharifi Mojtaba 
Published: February 2024

Abstract
Individuals with physical disabilities or chronic conditions resulting from afflictions such as strokes or spinal cord injuries are advised to use assistive devices to perform daily activities in everyday life for mobility assistance. Focusing on upper extremity assistance, this work aims to develop an upper limb exoskeleton for shoulder and elbow joints that is lightweight and cost-effective. Accordingly, this assistive device is comfortable and easy to operate in home settings, allowing these individuals to regain independence and making their daily lives and physical rehabilitation easier. This exoskeleton is designed to have adjustable dimensions for all body types and various disabilities or conditions. The proposed design ensures the user’s comfort with the capability of performing different movements within a wide range of motion. The structure of this upper limb exoskeleton was fabricated using lightweight materials such as polyethylene terephthalate glycol (PETG), thermoplastic polyurethane (TPU), aluminum, and carbon fiber sheets. High-torque DC motors (AK80-9 model from T-Motor) have been employed on the back of the trunk segment for actuating the exoskeleton joints. In this configuration, a cable-driven system (including Bowden cables and pulleys) has been used to minimize the inertia and weight of the moving parts. To reduce the overall cost and weight of this upper-limb exoskeleton further, each of the shoulder and elbow joints is only operated by one motor. To accommodate this limitation, a full range of motion is achieved for joints such as the shoulder by utilizing a gimbal-style mechanism, where the actuated joint can be repositioned and locked about a common center of rotation. This design decision makes it possible for the user to perform many different motions with the exoskeleton.
Comparison of Machine Learning Models and Analytical Scaling Law for Predicting Melt-Pool Depth in Laser Powder Bed Fusion (LPBF) Additive Manufacturing
Authors: Bai Feiyang , Arikatla Siva Surya Prakash Reddy , Zhang Nian , Gebre Fisseha L. , Xu Jiajun 
Published: February 2024

Abstract
Laser powder bed fusion (LPBF) is a widely used Additive Manufacturing (AM) process involving a high-powered laser to fuse metal powder and build up successive layers to create complex structures. Process parameter selection significantly impacts the dimensional characteristics of the melt pool morphology, including its depth and width, which is vital to the final print quality. Accurately predicting the melt-pool depth is critical for ensuring the quality of the final product. Various methods for different materials have been investigated, for example, thermal image analysis, analytical methods like scaling law, machine learning, and so on. However, most of the promising results are only studies for one material, and it is not necessarily fully applied to another material.
In this paper, our study involves utilizing machine learning models to make predictions of melt-pool depth in the LPBF process and compare their performance to an analytical approach based on scaling law with Nickel alloys IN625 and IN718. We trained three different machine learning models which are Gaussian Process Regression (GPR), Support Vector Machines (SVM), and Neural Networks (NN), and evaluated their performance using R-squared error and Root Mean Squared Error (RMSE) against the performance of the analytical scaling law. Our results show that the machine learning models outperform the scaling law approach significantly.
This study demonstrates the potential of machine learning for improving the accuracy of melt-pool depth prediction in LPBF and provides insights into the strengths and limitations of different machine learning models for this task.
Design and Development of Low-Temperature Ni Coating Without Plasma Using Atomic Layer Deposition
Authors: Box Garcia David , Brown Hayden , Gebre Fisseha , Dwivedi Vivek , Xu Jiajun 
Published: February 2024

Abstract
Atomic Layer Deposition (ALD) is a promising method for the deposition of thin film coatings on a variety of substrates. ALD is a chemical vapor deposition technique where the film growth rate can be highly controlled. Thin film coatings are present in everyday life, having myriad applications in the optics industry such as anti-reflective coatings. Moreover, many other technological fields like decorative or biomedical coatings benefit from this technology. A novel deposition is proposed utilizing diethylzinc (DEZ) and H2O to form a ZnO adhesion layer, followed by Ni (bis(dimethylamino-2-methyl-2-butoxo) in a vapor state and H2 forming gas to deposit 1–2 nm of uniform Ni. Current methods for the deposition of Ni utilize powdered Ni which must be sublimed and deposited in a plasma environment. Although the precision deposition of nickel is possible with this technique, impurities can be present. The objective of the study is to deposit Ni without plasma, utilizing the lowest possible thermal activation energy. Thickness, surface roughness, and composition are critical to understanding the quality of deposition. By using ellipsometry, thin-film thickness was determined with angstrom-level resolution which showed a growth rate of ∼ 2.2 Å per cycle. Surface roughness utilizing atomic force microscopy (AFM) identified a conformal surface with an average Ra of 0.94266 nm. Scanning electron microscopy (SEM) is used to supplement thickness measurements, investigate the crystalline structure, and generate high-quality images of the deposition.
Experimental Demonstration of a Novel Elastohydrodynamic Seal Concept for sCO2 Turbomachinery
Authors: Hassan Mohammad Fuad , Xu Hanping , Islam Mohammad Towhidul , Cesmeci Sevki , Liu Shuangbiao , Harcrow Aaron , Topu Ali Akbor , Hasan Md Wasif , Henry Jonah , Bunting Joshua , Dewis David , Tang Jing 
Published: February 2024

Abstract
To unlock the maximum ability of supercritical carbon dioxide (sCO2) power cycles, technological readiness must be established on the scale of 10–600 MWe and at the sCO2 temperatures and pressures of 350–700 °C and 20–35 MPa for nuclear industries. One of the major challenges at the component level is the lack of suitable shaft seals in sCO2 operating conditions. So far, all conventional seals are incapable of handling sCO2 pressures and temperatures in one way or another. Hence, we propose an elastohydrodynamic (EHD) high-pressure, high-temperature, and scalable shaft seal for sCO2 cycles. The distinctive mechanism of such an EHD seal provides a self-regulated constriction effect to restrict the flow without significant material contact, thereby minimizing leakage and wear. In this study, we conducted an experimental study to prove the EHD seal concept on a 2” static shaft. The shaft was made from stainless steel, whereas the test seal was made from PTFE. The experiments were performed for 121.25 μm initial clearance, and the operating pressure was increased up to 1.50 MPa. It was observed that the EHD seal throttled the leakage rate successfully. The leakage rate increased to a maximum of 7.33 g/s at around 0.64 MPa before it started to decay to 2.72 g/s at the maximum operating pressure of 1.50 MPa. This unique behavior of the EHD seal could become advantageous for sCO2 turbomachinery, where lower leakage rates are required at high pressure and temperature values.
Stenotic Cervical Spinal Cord and Column Responses Under Whiplash Using a Finite Element Model
Authors: Yoganandan Narayan , Harinathan Balaji , Vedantam Aditya 
Published: February 2024

Abstract
Numerous finite element models of the cervical spine have been developed to study the biomechanics of the osteoligamentous column such as range of motion and vertebral stress; however, the spinal cord is often ignored. Spine degeneration is often attributed to the ageing process. It may lead to stenotic spines that concern clinicians and patients because of the decreased space in the canal and potential for elevated risk of cord and/or column injuries. Using a validated model of the subaxial spinal column, spinal cord was included, and different degrees of stenosis (mild, moderate, and severe) identified in the civilian populations were parametrized. Stenosis was simulated at the most common, C5-C6 level, seen in patients. The column-cord model was subjected to postero-anterior acceleration at the base of the T1 vertebra. Range of motion, disc pressure, and stress and strain within the spinal cord were obtained at the index and superior and inferior adjacent levels of the column and cord. The external metric representing the segmental range of motion were found to be insensitive while intrinsic disc and cord variables were more sensitive, and index level was more affected by stenosis. These findings may influence surgical planning and patient education in personalized medicine.
Impact of Prior Design Experiences on Undergraduate Design Success
Authors: Kado Corey , Murphy Alexander R. , Bohm Matt , Kames Elisabeth 
Published: February 2024

Abstract
Design experiences are a critical component of undergraduate STEM education, as they challenge students both academically and socially. The goal of this study is to investigate how previous design experiences and engineering design self-efficacy impact project outcomes for a Hackathon style design project. This early-phase exploratory study observes first-year students in STEM-focused disciplines as they complete a six-hour ‘Hackathon’ style event. The Hackathon serves as the final requirement for the students’ interdisciplinary cornerstone design course. In this study, student demographics, K-12 prior experiences, and engineering design self-efficacy, were collected to understand how these different factors may influence student success throughout the Hackathon. The project is deemed a ‘Hackathon’ due to the problem-focus task given to the student participants and the variety of STEM skills required to arrive at a successful project outcome and a positive student learning experience.
The results of the study show significant correlation between the students’ prior exposure to design and engineering content before their undergraduate studies. Significant correlations were also observed between design self-efficacy factors and success in the Hackathon (measured through time of completion at various points). These findings have the potential to influence design pedagogy and team assignment criteria for future iterations of this cornerstone course and other curricular content focused on the engineering design process. The results of this study set the foundation for future work aimed at understanding our first-year engineering students’ prior design experiences and preparing them for academic success during undergraduate education. An extension of this work is planned that will facilitate longitudinal comparisons of achievement and progress across a four-year design experience.
Repurposed Desalination Salt: A Low-Cost Thermal Energy Storage Medium
Authors: Theroux Konnor M. , Salerno Christopher N. , Camey Brian C. , Salas Alex , Sephton Tom , Baghaei Lakeh Reza 
Published: February 2024

Abstract
In this techno-economic analysis, a thermal energy storage system that repurposes desalination salt as a storage medium is investigated. The proposed system meets the Department of Energy’s SunShot Initiative goal of $15/kWhth for thermal energy storage (TES). A sensitivity analysis was performed on significant cost factors to determine how to meet this goal while considering a positive financial gain from obtaining the salt from desalination facilities. Based on a previous TEA study, adjustments were made to the costs of labor and material to account for inflation. Nanoparticle additives are considered to enhance thermal conductivity and improve system efficiency. Furthermore, desalination concentrates with lower total dissolved solids (TDS) tends to provide lower TES cost. A ZLD (Zero Liquid Discharge) process was considered to extract the total dissolved solids from the desalination brine and provide an additional gain from the potable water sale. The overall $/kwh results show that the SunShot goal is met using a desalination salt that exhibits solid-to-liquid phase change.
Efficient Inverse Design of Acoustic Metamaterials Using Gradient-Based Optimization
Authors: Gerges Samer , Amirkulova Feruza A. , Samaniego Jovana 
Published: February 2024

Abstract
This work presents an efficient implementation of the inverse design of acoustic metamaterials using the gradient-based optimization (GBO) method. The inverse design is based on an optimization process using the semi-analytical optimization approach by adjusting the radius and position of each scatterer in the non-uniform planar configuration of scatterers of various radii. As an illustration of the method, the application of the GBO method for the design of an acoustic lens is demonstrated. The proposed inverse design method is implemented utilizing the GBO algorithms, such as the sequential quadratic programming (SQP) algorithms and the Julia programming language, which is suitable for large-scale simulations and optimization problems. Jointly they create a synergy that enhances the optimization process. The results are compared against computations performed on MATLAB using the f mincon solver with the SQP algorithms. This paper will present numerical examples of sound localization using random and symmetric non-uniform planar configurations of cylindrical rigid scatterers submerged in water.