bluuebunny/crossref_metadata_2025_split huggingface dataset:
Enhancement of Mechanical Engineering Education With Additive Manufacturing Projects
Authors: Billings Christopher , Siddique Zahed , Liu Yingtao 
Published: February 2021

Abstract
This paper presents an undergraduate research project developed to enhance mechanical engineering education at the University of Oklahoma. Selective Laser Sintering (SLS) is a promising additive manufacturing method for high-temperature materials with high spatial resolution and surface quality. As one of the most capable engineering-grade thermoplastics, polyether ketone (PEEK) can be used in additive manufacturing due to its elevated working temperature. This printer will use multiple heat zones, adjustable layer height, and a controlled hopper system to allow the user to fine-tune every print.
In this paper, students are required to analyze the technical challenges of SLS based 3D printing technology. Using three separate controlled heat zones, the user will be able to hold the part above its glass transition temperature until the entire part finishes, therefore, annealing it in the process. This will additionally allow for testing and documentation of the effect of heat during preheating, pre-sintering, and post sintering. These features in a small-scale machine will allow thorough documentation of how controlled heated environments can alter the physical properties of a 3D printed part. Using a full steel platform with CNC machined parts and an off the shelf laser, the cost will be reduced to under ten thousand dollars. This undergraduate project to design an SLS based 3D printer provide a unique opportunity for students to fully understand the challenges of SLS manufacturing and gain experience in developing a complex 3D printing system.
Popping Elbow Joint: Effects and Results
Authors: Salman Muhamad , Hadjimirzaei Anaheeta , Reed Sammy 
Published: February 2021

Abstract
The aim of this research project is to study patients with elbow instability and design a brace that will help with the injury. The idea for this research project was presented by one of the research partners who has suffered from elbow instability for 10 years. Elbow instability is a rare condition that is mostly unspoken about. Many live with this condition without knowing it exists or simply ignoring it. But the effects of this injury are painful and permanent, making it harder to perform daily tasks using the arm. This research will provide data for a possible medical device to help reduce forces on the elbow joint and help reduce pain from elbow instability. To better analyze data for this injury, the elbow joint must be placed under a force test. Two participants volunteered to perform the test by lifting a series of weights. Data for the Electromyograms (EMG) was then collected using only the Trigno Wireless Biofeedback System, placed above the humerus near elbow joint where the injury is most common. Another aspect of this research was to better understand the popping of the elbow joint. A 3D model of the elbow joint was then printed and further analyzed. All gathered data and analytics are used to study how a medical brace could possibly help with patients’ elbow instability. The final goal for this research will be to design and create a brace that will alleviate pain caused by elbow instability in the patient. The brace will allow users to endure repeated popping of the elbow joint while muscles are contracted and relaxed.
Calculation and Variation of Thermoelectric Properties of Phase Transition Materials
Authors: Vallin Micah P. , Zhang Richard Z. 
Published: February 2021

Abstract
Thermoelectric materials are defined as materials which can convert heat into electrical energy. Thermoelectric materials are often used for applications such as power generation or refrigeration. Because of the applications for thermoelectric materials, it is important to understand the electrical-to-thermal coupling behavior of such materials. The thermoelectric materials simulated are 2D film configurations of Tin Selenide (SnSe). Using the derivations for non-equilibrium electron-phonon dynamics as well as obtaining the phonon dispersions, second-order and third-order elastic constants, the thermoelectric properties can be calculated. For the purposes of this paper, the correlation of thermoelectric properties such as thermopwer, thermal conductivitty, and thermoelectric figure of merit with parameters such as the characteristic length of the 2D material as well as the applied voltages of 0 V/m, 10,000 V/m, and 20,000 V/m over the 2D material. Furthermore, an analysis on the effect of strain on the thermoelectric properties of SnSe is conducted.
Simulation of Ion Current in Oxyfuel Flame Subject to an Electric Field
Authors: Xu Kemu , Untaroiu Alexandrina , Martin Christopher 
Published: February 2021

Abstract
This paper presents a computational model to study ion and electron transportation and current-voltage characteristics inside a methane-oxygen flame. A commercial software is used to develop the model by splitting the simulation into the combustion and electrochemical transportation parts. A laboratory experiment is used to compare the results from the model. The initial and boundary conditions represented in the model are similar to the experimental conditions in the laboratory experiment.
In the combustion part, the general GRI3.0 mechanism plus three additional ionization reactions are applied and results are then used as input into the electrochemical transportation part. A particular inspection line is created to analyze the results of the electrochemical transportation part. Ion, electron number density, and current density are studied along the interval from −40V to 40V electric potential. The ions are heavier and more difficult to move than electrons. The results show that at both torch and work surfaces charged sheaths are formed and cause three different regions of current-voltage relations.
Microwave-Induced Thermoacoustic Compressive Imaging With Metamaterial Coding
Authors: Mao Xu , Liu Chang , Heredia-Juesas Juan , Martinez-Lorenzo Jose Angel 
Published: February 2021

Abstract
The microwave-induced thermoacoustic (TA) sensing has been proven to promise a great potential in clinical and biomedical applications. This novel technology has also been explored to boost its use in subsurface geophysical applications. A conventional TA sensing system, however, is greatly limited by either a slow scan or a dramatical cost, and making infeasible the real-time monitoring when covering large domains. One remarkable solution of such issues is to design a compressive sensing (CS)-based TA system, with the aim of reducing the sampling intensity necessary to high resolution imaging. Specifically, to favor the demand for CS, this work studies the appropriateness of metamaterial (MM) resonators and proposes a MM linear array-coded TA system to randomize the transmitted acoustics waves. To prove the efficacy, images obtained from both of the proposed TA system and the conventional TA system without coding are assessed and compared. Under the same scenario, the MM-coded TA system shows higher imaging capabilities and a better performance when using a much-limited amount of measurements or in noisy enviornments. This method opens the door for a fast scan of the geological imaging and the real-time monitoring of the underground flow.
Study on Natural Convection in Horizontal Parallel Plate Channels Heated on Upper Wall and Partially Filled With Metal Foam
Authors: Buonomo Bernardo , Fardella Vincenzo , Manca Oronzio , Nardini Sergio , Pragliola Salvatore 
Published: February 2021

Abstract
In this work, a numerical investigation on two-dimensional steady state natural convection in a horizontal channel partially filled with a porous medium and heated at uniform heat flux from above is carried out. The lower plate is adiabatic. The porous medium is modeled using the Brinkman–Forchheimer-extended Darcy model and the local thermal equilibrium (LTE) hypothesis is assumed. The structure of the porous medium is homogenous and isotropic, the thermophysical properties of the air and the porous medium are temperature independent and the fluid flow is laminar and incompressible. The aluminum foam has 10, 20 and 40 pore per inches (PPI) and its porosity ranges from 0.90 and 0.95. Rayleigh number values are examined, from 6.0 × 104 and 1.2 × 107. Results are presented in terms of velocity and temperature fields, temperature and velocity profiles at different significant sections are shown, to obtain a description of the natural convection inside the open-ended cavity. Finally, Average Nusselt number values are evaluated. The horizontal open cavity partially filled with metal foam presents improved heat transfer behavior for higher Rayleigh numbers. The enhancement depends on the porosity and pore density. The average Nusselt number for the partially filled open cavity is the double of the configuration without the foam, clear configuration, for the highest considered Rayleigh number.
Effects of Tire Attributes on Aerodynamic Performance
Authors: Fu Gen , Untaroiu Alexandrina 
Published: February 2021

Abstract
As indicated by previous studies, many attributes of tires have been shown to have an impact on tire aerodynamic drag. However, the way these attributes affect tire aerodynamics has not been systematically investigated to date. It is not clear which tire attributes have the most significant impact on aerodynamic drag. Therefore, a sensitivity study of the effects of tire attributes on tire aerodynamic performance is proposed in this study. This sensitivity study improves the understanding of flow structures and mechanisms around tires.
First, a baseline CFD model of a tire is created and validated by experimental data. In the computational model, the tire is positioned in a wind tunnel to match the experimental testing configuration. A hybrid boundary condition method is used to simulate a rotating tire. Based on the validated baseline model, various tire attributes are considered and compared in the study proposed. The tire attributes considered include tire width, tire side wall profile, lateral grooves, and open rim design. There are five cases in total for the sensitivity study. Then the effects of these attributes on the tire aerodynamic drag are calculated and compared. The most influencing feature is then identified. The results show that a smoothed side wall profile with smaller radius can improve the aerodynamic performance of an isolated tire. On the other hand, the influence of lateral grooves on tire aerodynamic performance is limited. The force integrated from all lateral groove surfaces only account to less than 2% of the total tire drag force. Additionally, an idealized open rim design changes the flow structure significantly, which leads to the increase of aerodynamic drag. The force integrated on the rim surface account for up to 20% of the overall tire drag force.
Standards for Evaluating the Influence of Materials on the Performance of X-Ray Computed Tomography in Measuring Geometric Variability
Authors: Shakarji Craig M. , Srinivasan Vijay , Lee Vincent D. , Shilling Meghan , Muralikrishnan Bala 
Published: February 2021

Abstract
The industrial use of X-ray Computed Tomography (known briefly as XCT, or sometimes simply as CT) is on the rise because a single XCT scan can measure an arbitrary number of features, and XCT instruments can measure features inaccessible to contact or optical instruments — even features that are completely encased in material. This makes XCT a natural metrological companion to additive manufacturing where internal features (e.g., lattice structures) can be produced. But this advantage of being able to measure through material is somewhat mitigated by the fact that the obstructing material has a strong influence on the geometric measurement and is a dominant source of error. This problem is addressed by two emerging documentary standards in ASME and ISO (International Organization for Standardization). These documents define standardized tests for metrological accuracies of an XCT system, where accuracies — now unambiguously defined — can be expressed as Maximum Permissible Errors (MPEs). These tests rely on calibrated artifacts that are designed to reveal various XCT error sources when the system measures these artifacts in prescribed manners. This paper gives the general philosophy behind Coordinate Measuring System standards and then applies them to XCT systems in particular. Rationale is given for the artifact choices contained within these standards, with particular emphasis on material effects, and clarifies the metrological coverage of these standards.
Computational Design Method to Control Touch Feeling of Mattress With Geometric Surface-Shape
Authors: Nishio Ken , Sakuma Atsushi 
Published: February 2021

Abstract
Foam material is one of the ingredients that are frequently used for controlling of touch feeling on the contacting part of various products like bed mattresses. For better sleep, it is necessary to design to control the touch feeling of the mattresses. Touch feeling depends on various properties of the foam material, and the shape characteristics of the contact part also give humans various and complicated feelings. According to previous studies, it was possible to easily quantify the physical properties of foam materials by using indentation test. Furthermore, it is necessary to analyze the change in touch feeling due to the shape of contact part of foams for better mattress design.
Therefore, in this report, the purpose is to analyze the contact problem including the material property and the shape property of the foam material. A new softness parameter was created by analyzing the contact problem using FEM analysis. Specifically, it is report a design technology based on multiple parameters of tactile sensation that change depending on the shape of the contact part of the foam material.
Design an Augmentation Exoskeleton to Enhance Lifting Strength
Authors: Liu Yilang , Chen Yuhao , Li Hongyi , Dong Janet 
Published: February 2021

Abstract
This paper describes the process of a team of mechanical engineering students in designing and simulating an easy to wear augmentation exoskeleton device. The goal of the project is to develop a fundamental technology associate with the design and control of an upper-body exoskeleton that augments human arm strength and endurance during lifting motion. The technology is intended to be used by military soldiers who are required to frequently lift more than 100 pounds objects, such as heavy machinery, tank ammunition, etc.
This proof of concept design focuses on using a wearable device to provide and support both arms with considerable strength to lift more than 100 pounds objects. Some of the features of this upper body exoskeleton include easy to wear, light weight, portable, sturdy, and easy to control. The exoskeleton device mainly consists of two sections: wearable body vest and EMG sensors and Arduino control system.
This paper also discussed the range of basic motion of the arms, how the wearable exoskeleton device is developed, and how the performance and efficiency of such device are evaluated.
How Many Valid Days Are Necessary to Assess Physical Activity Data From Accelerometry During Pregnancy?
Authors: da Silva Danilo Fernandes , Mohammad Shuhiba , Nagpal Taniya Singh , Souza Sara Carolina Scremin , Colley Rachel C. , Adamo Kristi Bree 
Published: February 2021

Background: The authors examined whether or not ≤3 days wearing Actical® accelerometers provided acceptable results in comparison with the recommendation of ≥4 days in women across gestation. Methods: A total of 26, 76, and 57 participants at early, mid, and late pregnancy, respectively, were assessed. Participants were instructed to wear the device for 7 days and women who wore it for ≥4 days were included. For each participant, 3, 2, and 1 day(s) were randomly selected. Paired comparisons, intraclass correlations coefficients, and kappa statistics were performed for ≥4 days (criterion) versus 3, 2, and 1 day(s). Averages (in minutes per day) of sedentary time, light, moderate, vigorous, moderate to vigorous physical activity (PA) and steps per day were examined. Results: When 3 valid days were compared with the criterion, no significant differences were found for any gestational period. The intraclass correlations coefficients were “high” for all PA-related variables. The k values varied from .819 to .838 across pregnancy (“strong”). Two and 1 valid day(s) versus the criterion showed significant differences in some PA intensities, reduced intraclass correlations coefficients, “moderate” k values for 2 valid days (.638–.788) and “minimal-to-moderate” k values for 1 valid day (.367–.755). Conclusion: In pregnant women during early, mid, and late pregnancy, PA data obtained from 3 valid days of wear was equivalent and agreed with ≥4 valid days.
Critical Pause: Athletes’ Stories of Lockdown During COVID-19
Authors: Whitcomb-Khan Gabriella , Wadsworth Nick , McGinty-Minister Kristin , Bicker Stewart , Swettenham Laura , Tod David 
Published: February 2021

This study explored the experiences of elite athletes during the initial stages of lockdown as a result of the COVID-19 pandemic. The eight recruited participants (three females, five males) were asked to tell a story of their lockdown experience. Narrative analysis was used to explore the athletes’ stories. The athletes’ narrative is best represented in four distinct sections: (a) threat to goals, (b) ongoing consequences, (c) overcoming COVID-19, and (d) adapting to COVID-19. Four narrative themes were also coconstructed from the athletes’ stories: (a) factors athletes found challenging, (b) loss, (c) strategies that benefitted athletes psychologically, and (d) silver linings. Combined, these findings suggest that the initial stages of lockdown are best described as acritical pause. The authors present applied implications for athletes and sport psychology practitioners. The authors also recommend that future research investigate the longitudinal effect of prolonged lockdown on athletes’ lives and a potential return to sport.
Use of SNP chips to detect rare pathogenic variants: retrospective, population based diagnostic evaluation
Authors: MN Weedon , L Jackson , JW Harrison , KS Ruth , J Tyrrell , AT Hattersley , CF Wright 
Published: February 2021

AbstractObjectiveTo determine whether the sensitivity and specificity of SNP chips are adequate for detecting rare pathogenic variants in a clinically unselected population.DesignRetrospective, population based diagnostic evaluation.Participants49 908 people recruited to the UK Biobank with SNP chip and next generation sequencing data, and an additional 21 people who purchased consumer genetic tests and shared their data online via the Personal Genome Project.Main outcome measuresGenotyping (that is, identification of the correct DNA base at a specific genomic location) using SNP chips versus sequencing, with results split by frequency of that genotype in the population. Rare pathogenic variants in theBRCA1andBRCA2genes were selected as an exemplar for detailed analysis of clinically actionable variants in the UK Biobank, and BRCA related cancers (breast, ovarian, prostate, and pancreatic) were assessed in participants through use of cancer registry data.ResultsOverall, genotyping using SNP chips performed well compared with sequencing; sensitivity, specificity, positive predictive value, and negative predictive value were all above 99% for 108 574 common variants directly genotyped on the SNP chips and sequenced in the UK Biobank. However, the likelihood of a true positive result decreased dramatically with decreasing variant frequency; for variants that are very rare in the population, with a frequency below 0.001% in UK Biobank, the positive predictive value was very low and only 16% of 4757 heterozygous genotypes from the SNP chips were confirmed with sequencing data. Results were similar for SNP chip data from the Personal Genome Project, and 20/21 individuals analysed had at least one false positive rare pathogenic variant that had been incorrectly genotyped. For pathogenic variants in theBRCA1andBRCA2genes, which are individually very rare, the overall performance metrics for the SNP chips versus sequencing in the UK Biobank were: sensitivity 34.6%, specificity 98.3%, positive predictive value 4.2%, and negative predictive value 99.9%. Rates of BRCA related cancers in UK Biobank participants with a positive SNP chip result were similar to those for age matched controls (odds ratio 1.31, 95% confidence interval 0.99 to 1.71) because the vast majority of variants were false positives, whereas sequence positive participants had a significantly increased risk (odds ratio 4.05, 2.72 to 6.03).ConclusionsSNP chips are extremely unreliable for genotyping very rare pathogenic variants and should not be used to guide health decisions without validation.
Comparing the effects of tofogliflozin and pioglitazone in non-alcoholic fatty liver disease patients with type 2 diabetes mellitus (ToPiND study): a randomized prospective open-label controlled trial
Authors: Yoneda Masato , Honda Yasushi , Ogawa Yuji , Kessoku Takaomi , Kobayashi Takashi , Imajo Kento , Ozaki Anna , Nogami Asako , Taguri Masataka , Yamanaka Takeharu , Kirikoshi Hiroyuki , Iwasaki Tomoyuki , Kurihashi Takeo , Saito Satoru , Nakajima Atsushi 
Published: February 2021

IntroductionThe treatment of diabetes has a significant impact on the pathogenesis of non-alcoholic fatty liver disease (NAFLD). We compared the effectiveness of tofogliflozin, a selective sodium-glucose cotransporter 2 inhibitor, and pioglitazone for the treatment of NAFLD patients with type 2 diabetes mellitus.Research design and methodsThis open-label, prospective, single-center, randomized clinical trial recruited NAFLD patients with type 2 diabetes mellitus and a hepatic fat fraction of at least 10% as assessed based on the MRI-proton density fat fraction (MRI-PDFF). Eligible patients were stratified according to hemoglobin A1c (HbA1c), alanine transaminase, and MRI-PDFF levels and randomly assigned (1:1) to receive either 20 mg tofogliflozin or 15–30 mg pioglitazone, orally, once daily for 24 weeks. The primary endpoint was an absolute change in MRI-PDFF at 24 weeks. Efficacy and safety was assessed in all treated patients. This trial was registered in the Japan Registry of Clinical Trials.ResultsOverall, 40 eligible patients were randomly assigned to receive tofogliflozin (n=21) or pioglitazone (n=19). Changes in hepatic steatosis after 24 weeks of treatment were evaluated by MRI-PDFF, which showed a significant decrease in both groups (−7.54% (p<0.0001) and −4.12% (p=0.0042) in the pioglitazone and tofogliflozin groups, respectively). Compared with baseline, the body weight decreased by 2.83±2.86 kg (−3.6%, p=0.0443) in the tofogliflozin group and increased by 1.39±2.62 kg (1.7%, p=0.0002) in the pioglitazone group after 24 weeks. No life-threatening events or treatment-related deaths occurred.ConclusionsTofogliflozin was well tolerated, and it reduced the MRI-PDFF levels in NAFLD patients with type 2 diabetes mellitus.Trial registration numberjRCTs031180159.