bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Composite Structure for Low-Frequency Sound Absorption With Continuous Broadband Under High Sound Pressure Excitations
Authors: Zhu Junzhe , Gao Hao , Qu Yegao , Meng Guang 
Published: February 2024

Abstract
High-amplitude sound absorption in the low-frequency range is of great interest because of its vast engineering applications. This work is associated with a novel composite multilayer structure for high-amplitude sound energy attenuation. An analytical model based on the equivalent fluid method by using JCAL (Johnson-Champoux-Allard-Lafarge) model is used to predict the sound absorption performance of the multilayer structure both under 90 dB excitation and 140 dB excitation. Numerical simulation is applied to verify the accuracy of the analytical model. This work demonstrates four samples with different parameters to compare the analytical and numerical results. The results of the two methods agree well with each other. The resonance frequencies of all samples locate in the low-frequency range. It is also found that the resistance of the multilayer structure is enlarged as the sound excitation increases, which can be utilized to design high-intensity sound energy absorbers. The sound absorption coefficient is improved under high sound pressure excitations. To further broaden the sound absorption bandwidth in the low-frequency range, a composite multilayer structure with three absorption units is designed to achieve high-efficiency sound absorption continuously. The composite structures combine the sound absorption performance of each unit and three absorption peaks occur in the low-frequency range. The experiments are performed to verify the sound absorption performance of the proposed structure. The results show that the designed composite multilayer structure has a superior noise reduction capability with continuous bandwidth under high sound pressure excitations in the low-frequency range.
Motion Control of a Robot by Means of Q-Learning Using the Example of Locomotion
Authors: Bußmann Tobias , Schilberg Daniel 
Published: February 2024

Abstract
The aim is to program a robot who learns a movement using Q-Learning. A neural network is used to process the data. To check whether the robot has learned successfully, four requirements were made of the robot. Various experiments were carried out with the robot, in which the parameters of the learning algorithm or the neural network were varied. The results of the experiments show that the robot fulfills every requirement, except in the experiments where the neural network diverges and the robot does not learn any strategy to reach the goal.
Virus Transmission Aboard a Transit Bus
Authors: Bonifacio Jeremy , Rahai Hamid , Horstman Raymond 
Published: February 2024

Abstract
Unsteady numerical simulations of virus transport released from an infectious passenger aboard a transit bus have been investigated. The goal of the investigation was to explore methods for controlling the spread of a virus or any contaminants aboard a public transportation system for improving public health. The virus was modeled as a 2.5 μm round solid particle released from the mouth of the infectious passenger at a rate of 21 particles per second at a mouth velocity of 0.278 m/sec. The air delivery to the cabin was two linear ceiling slots spanning the length of the bus delivering 59.38 m3/min (2,097 CFM) of air at a mean velocity of 1 m/sec. Axial linear exhaust slots placed on the side walls have been investigated to contain and prevent the spread of the virus to the other parts of the cabin. Simulations were performed for both cases of the bus in transit and at the bus stop when the drop-off door was opened. Results indicate during the transit, virus spread was contained to passengers sitting in immediate front and behind the infectious passenger and the level of virus concentration could merit an increased risk of infection with increased virus residence time. However, augmented air mixing was observed between inside and outside air during the passenger drop-off with viruses spread to the front and back of the bus with reduced concentration and risk of infection. Analytical analyses of the risk of infection using the Wells-Riley equation have shown that with axial slots, the viruses are contained around the infectious but with the increased concentration, the risk of infection for these passengers is increased.
ADAMS Multibody Simulation of Jamming in the Recirculation Channel of a Single-Nut Ball Screw
Authors: Bertolino Antonio Carlo , De Martin Andrea , Guida Roberto , Sorli Massimo 
Published: February 2024

Abstract
Ball screw jamming is a significant concern as it can have a detrimental impact on the performance and reliability of ball screw systems, potentially leading to a complete loss of mechanical power transmission. However, no studies in the literature have conducted dynamic analyses to investigate the effect of such fault on the performance of this mechanism. This article reports on the findings of a simulation analysis using a detailed multi-body dynamic model developed in the MSC ADAMS environment to exploit its capabilities of describing contacts between arbitrary shaped bodies and accounting for the complete dynamics of each subcomponent. The analysis focused on a single-nut not preloaded ball screw with three axisymmetric sphere internal recirculating circuits and compliant constraints. The results of an extensive validation process of the mathematical model against literature data in nominal conditions are firstly presented to enhance the reliability of the results. Then, the outcomes of the simulation campaign are presented, investigating the impact of different numbers of recirculation channel jammings on the overall mechanical efficiency and the internal behavior of the spheres, for different lubrication conditions. The findings of this study provide valuable insights into the behavior of ball screw systems under jamming conditions and can lay the foundations for in-depth analyses and the development of a prognostic framework for such devices.
Design Improvement and Field Testing for Biogas Power Generation System
Authors: Song Yuxin , Duan Shawn 
Published: February 2024

Abstract
This paper details the process of obtaining high-purity methane from biogas by using specific filtering and drying devices and utilizing it as fuel to drive generators for electricity generation. The system is designed to filter out most impurities from the biogas produced from the fermentation of biological waste (cow manure), using a purification device to extract methane. The conversion kit uses methane to run the generator to produce electrical energy. Field tests were carried out to ensure the proper functioning of the experimental setup, considering interference factors such as temperature changes, weather factors, and natural fermentation effects. The design flaws were identified during the testing, such as airtightness problems that led to system failure and inaccurate data. Control variable method was used to resolve these issues, and some parts were replaced through redesign and testing to ensure the proper functioning of all components. Finally, it was found that adding a certain amount of Sodium hydroxide (NaOH) to the water tank significantly improved the impurity removal effect, achieving the expected result. The testing results showed that percentage of methane reached 89.57%, while carbon dioxide dropped from 48.17% to 5.02%, and Hydrogen sulfide was removed completely. The generator with a conversion kit was able to produce 0.0705 kw · h of electricity by running on 8-Psi purified biogas for three minutes. Redesign and testing have validated design idea and achieved goal of the project.
Impact of Online Versus In-Person Group Work on Behavioral Peer Evaluations in Engineering Capstone Team Projects
Authors: Mishur Juliana , Niemi Sean R. , Underhill Janna L. , Traum Matthew J. 
Published: February 2024

Abstract
A critical open question in the mechanical engineering pedagogical literature is whether Capstone senior design can be taught as effectively online as in-person with emphasis on whether group work conducted under these contrasting conditions is equally effective. The onset of COVID-19 induced a natural experiment enabling comparison of engineering student group work conducted in-person versus all-online.
Group work is an essential element of mechanical engineering education codified by Student Outcome 5 of ABET Criterion 3 (Groupwork). Peer evaluation is a common engineering group work assessment, especially in Capstone design courses. In this paper, recurring peer evaluations are evaluated to quantify how well students performed in groups within a longitudinal study conducted across five semesters of a mechanical engineering Capstone senior design course.
In UF’s Mechanical Engineering Capstone courses, recuring peer evaluation surveys tied to group assignment deadlines were already established prior to COVID-19. By continuing to deploy this same survey when courses transitioned online during the pandemic, three full semesters of group performance data were collected when students were forced to meet remotely. As students returned to campus, the same survey provided comparative data for two semesters when students were meeting in person. These collected data represent a quantitative tool to evaluate how online vs. in-person group meeting setting impacts the quality of teamwork.
This work shows that online vs. in-person meeting environments DID NOT have statistically significant impacts on teamwork performance for mechanical engineering Capstone students in the semesters being evaluated. This result suggests that ABET Criterion 3 Student Outcome 5 can be met just as effectively in online or in-person Capstone courses.
This important result debunks the misconception that the quality and fidelity of Capstone groupwork is somehow diminished when senior design is taught online to learners remote from each other over the Internet. This finding adds to the growing body of evidence supporting the viability of an all-online Bachelor of Science in mechanical engineering program capable of receiving and maintaining ABET accreditation. Moreover, a forward-looking online ME program can include an effective Capstone senior design course with rich student groupwork interactions of quality equal to those experienced by students when meeting in-person.
Experimental Investigation and Optimization of the Effect of Burnishing Process Parameters on Surface Roughness and Hardness of Al 2036
Authors: Asadbeygi Alireza , Rezaei Hamed , Jalali Aghchai Abdolhossein 
Published: February 2024

Abstract
Surface roughness and hardness of work pieces have been always of great importance in the manufacturing industry. Burnishing as a surface treatment process is taken into consideration as a result of its great effect on surface quality. The objective of this work is to investigate the effect of roller burnishing process parameters on roughness and hardness of work pieces for aluminum 2036 alloy. Burnishing speed (Vc), feed rate (Vf), applied force (F) and depth of penetration (Dp) are assumed as the input parameters. In the experimental procedure, tests were designed based on Central Composite Design (CCD) design of experiments. A quadratic regression model for the surface roughness reduction is proposed and a parametric study is performed based on the developed model. Finally, the process parameters were optimized in order to achieve the lowest value of surface roughness. The results indicate that following the burnishing process, the average surface roughness of 31 samples decreased by 49.7% and the average surface hardness increased by 25.1%. By applying the optimal process parameters, A roughness reduction of 1.19 Ra (84%) was achieved, which was predicted by the model with an error of 8.4%.
Development and Aerodynamic Performance of an Axisymmetric-Sector Inertial Particle Separator Wind Tunnel
Authors: Rodriguez-Saenz Cesar R. , Loth Eric , Smith C. Frederic 
Published: February 2024

Abstract
An Inertial Particle Separator (IPS) can help reduce performance degradation of gas turbine engines used in aircraft when operating in dusty environments. In particular, an IPS geometry uses flow curvature to separate particles from the core flow path, so they are ideally fully directed into the scavenge flow path. To better understand the multiphase flow physics and performance of an IPS system, an axisymmetric-sector vertical bifurcated wind tunnel was developed and tested. This wind tunnel was designed to emulate the fluid and particle physics associated with the axisymmetric flow bifurcation for typical operational conditions. The wind tunnel employs a 50-degree sector angle to allow optical accessibility combined with a ratio of throat height to throat radius of 0.17. The tunnel uses a geometry representative of typical systems in terms of air flow velocities but with a size of about 40% (based on throat height) relative to full-scale systems. The wind tunnel air flow is achieved with two exhaust blowers and a calibrated control system, which allows for high mass-flow stability and a wide range of flow split ratios between the core and scavenge flows. To characterize the tunnel’s aerodynamic performance, measurements were taken for mass-flow stability and surface flow visualization to investigate corner flows and separation regions. The results indicate that the flow is highly stable and has separation regions qualitatively similar to those seen in 2-D facilities.
Fast Fourier Transform Method in Peridynamic Micromechanics of Composites
Authors: Buryachenko Valeriy A. 
Published: February 2024

Abstract
We consider a static linear bond-based peridynamic (proposed by Silling, see J. Mech. Phys. Solids 2000; 48:175–209) composite materials (CMs) of a periodic structure. In the framework of the second background of micromechanics (called also computational analytical micromechanics), one proved that local micromechanics (LM) and peridynamic micromechanics (PM) are formally similar to each other for CM of both random and periodic structures. It gives an opportunity for straightforward generalization of LM methods (including fast Fourier transform, FFT) to their PM counterparts. So, in the PM counterpart of the implicit periodic Lippmann-Schwinger (L-S) equation in LM, we have three convolution kernels corresponding to the properties of the matrix, inclusions, and interaction interface. Eshelby tensor in LM depending on the inclusion shape is replaced by PM counterparts depending on the shapes of inclusions and interaction interface (although the Eshelby concept of homogeneous eigenfields does no work in PM). The mentioned tensors are estimated one time (as in LM) in a frequency domain (also by the FFT method). The polarization schemes of the solution of L-S equation in the Fourier space have one primary unknown variable (polarization) whereas the PM counterpart contains three primary ones estimated at each step which are formally similar to LM case. Computational complexities O(Nlog2N) of the FFT methods are the same in both LM and PM.
Residual Stress Evaluation of Multilayer Viscoelastic Composites Using Ultrasonic Acoustoelastic Effects
Authors: Jiang Houfu , Shen Yanfeng , Zhang Tao 
Published: February 2024

Abstract
This paper proposes the advancement of residual stress evaluation technology, utilizing the ultrasonic acoustoelastic theory by detecting the variation of wave speed under different stress conditions. The target structure for nondestructive evaluation task is a typical multilayer, viscoelastic composite shell of a solid rocket motor. By carrying out an in-depth theoretical analysis with Finite Element Modeling (FEM), the sensing sensitivity of the probing ultrasonic wave characteristics are studied systematically. The effective generation of interface guided wave modes is investigated, where the pure wave mode excitation is accomplished. To monitor the residual stress state, a theoretical model is established by considering the stress gradient in each layer, indicating the current stress condition inside the testing object. Consequently, via the comprehensive consideration of transducer dimensions, center frequency, and the signal attenuation, the most effective residual stress monitoring setup is established and the sensing signals are recorded by piezoelectric wafer active sensors (PWAS) placing on the object. Finally, different values of prestress are applied to the object, while the nonlinear constitutive law of the layered materials is implemented. The pattern between the sensing signal and the residual stress state is identified. The amplitude and the Time of Flight (TOF) of sensing signals could provide indicative information for evaluating the residual stress state based on the acoustoelastic effects, including the change of wave speed under various prestress loading conditions. The findings of this research possess superb application potential for the evaluation of residual stresses in multilayer composites for enhancing manufacturing quality and avoiding unexpected failures in solid rocket motor industry. This paper finishes with summary, concluding remarks, and suggestions for future work.
Vascular Model of Liver Fibrosis
Authors: Torres Rojas Aimee M. , Lorente Sylvie 
Published: February 2024

Abstract
The liver has a very peculiar blood circulatory system composed of two blood supply vascular trees (the hepatic artery and portal venous networks), microcirculation through small functional units called lobules, and a blood drainage vascular tree (the hepatic vein network). In the healthy liver, flow resistance at the microcirculation level is very low and the portal pressure is almost the same as the lobules pressure. On the other hand, vasculature changes due to fibrosis — located predominantly at the lobules level — lead to a marked increase in resistance to flow causing an increase in portal pressure (portal hypertension). Here, a rigid model of the entire liver vasculature is built, where hepatic networks are considered as tree-like fluidic networks and lobules as a porous medium. The model can provide the blood flow and pressure within their healthy physiological ranges at all points of the vasculature. To simulate liver fibrosis, the portal hypertension it causes is reproduced. The high portal pressure values reported for fibrotic patients are used to calculate the necessary lobules permeability resulting in these pressure values at the inlet of the lobules. The decrease in the permeability of the fibrotic lobules causes a redistribution of flow between the two blood supply networks. The alterations of microcirculation due to fibrosis are also analyzed: increases in blood flow through the non-fibrotic lobules and decreases in blood flow through the fibrotic ones are observed, relative to blood flow through the lobules in a healthy liver.
Review of the Reliability and Feasibility of Existing Databases for Automated Vehicle Safety
Authors: Kim Eun Young , Wijesekera Duminda , Kan Cing-Dao , Park Chung-Kyu 
Published: February 2024

Abstract
The objective of this study is to use the existing databases on road information, crash information, and automated vehicle information towards designing accident avoidance mechanisms for automated vehicles. We use two main methods. The first is text clustering analysis that is used for grouping data from the existing safety databases into different categories assigned automatically. The second is using text classification analysis that is used to identify categories in two different datasets: the data elements and the data frames from the SAE J2735 V2X Communication Message Set Dictionary.
Based on outputs of two analysis methods, an assessment was performed by comparing the categories from the existing databases and from the V2X dictionary. Firstly, the outputs of the text clustering analysis demonstrated data diversity with various categories evenly weighted. On the other hand, the outputs of the text classification analysis showed that one category with respect to automated vehicle driving is highly concentrated. Thus, an assumption can be drawn that the existing databases are valid to support a communication application of automated vehicles. Additionally, keywords used for identifying the categories in the text clustering analysis indicate that they are similar with words from the data elements and data frames in the V2X dictionary. It presumes that data attributes are comparable to utilize the existing database to automated vehicles. This research shows that the use of the existing safety databases would be reliable and feasible for automated vehicles with evidence of data diversity and data similarity.
Structural Rigidity Analysis of Inflatable Wing Designs Constructed With High-Performance Fabric Membranes
Authors: Song Yuyang , Cavallaro Paul V. , Sadegh Ali M. 
Published: February 2024

Abstract
This research investigates competing design concepts supporting the development of a large-scale inflatable aerial wing capable of providing wind energy harvesting, telecommunications, and meteorology tracking. High Performance Fabric (HPF) membrane designs coupled with inflatable technologies are utilized because of their combined structural advantages such as lightweight; high strengths; flexibility; elastic recovery from overloading events including wind gusts; high packing efficiencies; etc. A comparative study is presented for two different inflatable structures; one is the baffled inflatable airfoil, where we investigate a different number of internal baffles bonded within a single airfoil envelope, normally shaped with a NACA4315 profile. The other is a drop-stitch inflatable airfoil, also known as 3-D woven fabric. By using the same high-stiffness fabric materials, the structural rigidities, bending load capacities and weights of these two membrane airfoil designs are compared through finite element analysis (FEA) modeling. It is shown that the inflatable baffled airfoil design exhibits greater stiffness-to-weight ratios compared to the drop-stitch inflatable airfoil design. The number of baffles within the baffled airfoil plays a significant role for: (1) mitigating peel stresses in the bonds between the skins and baffles, increasing the load carrying capacities prior to wrinkling and (3) increasing the overall bending stiffness. This research identifies the advantages and limitations of competing inflatable airfoil concepts and serves to increase the knowledge base for future inflatable structures and their applications.