bluuebunny/crossref_metadata_2025 huggingface dataset:
Visual Servoing for Robotic In-Space Welding Joint Fit-Up
Authors: Chacon Aida , Reyes-Munoz Julio A. , Mendoza Christopher , Valencia Alexis , Molinar Juan , Flores-Abad Angel
Published: January 2025

This paper explores the use of visual servoing for robotic in-space welding joint fit-ups, demonstrating its potential to achieve high accuracy within in-space welding guidelines in a simulated reduced-gravity environment. The experimental setup includes a UR5e robotic arm and a 2 Degree of Freedom (DOF) robotic arm on a floating sled, simulating a large robotic arm on the International Space Station (ISS) and a robotic satellite, respectively. Two triangular aluminum parts serve as the workpieces and are held by the robotic arms. Two cameras provide visual input, with Python scripts utilizing OpenCV and Robot Operating System (ROS) for real-time feedback and alignment data extraction to create a welded joint fit-up butt-weld. Target alignment data is communicated to the robot controller to execute the motion. The proposed system aims to meet Earth-based welding standards’ accuracy, enabling autonomous robotic welding fit-ups in space. Preliminary results show that the position and orientation (pose) planner can successfully receive and process data, validating the system’s feasibility.
Development and Application of a Mathematical Model for the Quantification of Induced Air and Its Extraction at Bulk Material Transfer Points
Authors: Bozo Efrain , Bozo Gonzalo
Published: January 2025

One of the most used methods to mitigate fugitive dust during bulk material transfers is the extraction of air generated by the falling material, where the airflow is defined by matching it to the calculation of induced air in a confined space.

The motivation behind this study arises from the lack of a mathematical model to quantify the induced air in transfers with wide or no confinement, as well as the limitations identified in traditional theoretical-empirical formulations used for transfers with narrow confinement. These equations do not consider the material trajectory, rock beds, high velocity, high material flow, or the actual behavior of the airflow during the transfer process and after impact in the receiving area.

This study shifts the focus towards developing a mathematical model that considers the material trajectory and the theoretical physical concept of induced airflow. The objective is to obtain, for the first time, a mathematical model to quantify the volume of induced air during the dynamic process of bulk material transfer in unconfined or widely confined spaces. This equation provides the upper limit of the induced area, allowing its applicability to be extended to scenarios with narrow confinement using one of the traditional equations. The model was validated through flow analysis and measurements in a transfer between conveyor belts. The results indicate a significant improvement in the accuracy of the estimated induced air volume compared to previous methods, demonstrating its applicability in various material transfer scenarios. Specifically, this model covers an area not previously addressed, such as the model for induced air without confinement or with wide confinement, which allows for the calculation of the upper induced area and the determination of recirculation efficiency in any transfer with narrow confinement. In other words, it allows for a more accurate determination of the air to be extracted.

The underlying premise of the model is based on the principle that, during the free-fall of the material occurring in a defined lapsus of time, all the natural interstices of the material are occupied by the surrounding air, causing a difference between the initial volume of the material and the final volume due to expansion which, in turn, determines the volume of air induced per unit of time incorporated after the impact.
An Investigation on the Shape Sensitivity of the Electroactive Membrane With Higher-Order Approximation
Authors: Fernandez Bianca , Sarker Pratik , Rahman M. Shafiqur
Published: January 2025

The electroactive polymer is a class of smart material undergoing mechanical deformation when subjected to electric excitation. They have great potential for proper control and maneuvering of small-scale aerial vehicles. The dielectric elastomer is an electroactive polymer undergoing large strain with electric stimulation. Lower-order approximation of the corresponding material behavior cannot predict proper aeroelastic, aerodynamic, and modal characteristics of the material. Besides, different shapes of dielectric elastomers also affect the overall dynamic characteristics. In this research, dynamic behavior of different shapes of VHB 4910 dielectric elastomer membranes under electric excitation and fluid flow are studied using a higher order hyperelastic model. The modal characteristics of the membrane are analyzed for a certain prestretch ratio and different electric excitations by finite element analysis. A computational fluid-structure interaction model is developed to observe the aeroelastic and aerodynamic characteristics of the membrane. Coefficients of aerodynamic forces are estimated for different angles of attack. A comparison of aeroelastic characteristics for several shapes of the membrane is performed for different electric excitations. It is found that the prestretch ratio and electric excitation have influences on aeroelastic, aerodynamic, and modal characteristics of the membrane which can be altered accordingly for proper control of small-scale aerial structures.
Finite Element Analysis of Taper and Straight Porous Dental Implants
Authors: Mehboob Hassan , Ouldyerou Abdelhak , Mehboob Ali , Barsoum Imad
Published: January 2025

Conventional dental implants, typically made of dense titanium, exhibit mechanical properties significantly higher than cancellous and cortical bone, leading to stress shielding and potential implant failure. This study aims to evaluate porous and dense implants with tapered and straight designs using the finite element method. The implants were fully bonded with bone to mimic full osseointegration. A load of 200 N was applied to the crown to mimic the chewing forces. The results showed that the tapered porous implant experienced the highest stress in cancellous bone (6.50 MPa), while the straight dense implant recorded the lowest (3.57 MPa). Conversely, the straight dense implant exhibited maximum stress (181.60 MPa) compared to the porous tapered implant (13.07 MPa). However, straight-dense implants demonstrated a higher factor of safety relative to porous implants. Biomechanically, the porous tapered implant outperforms conventional implants and may mitigate associated complications.
Exploring Physics-Informed Machine Learning for a Cylinder in Cross Flow
Authors: An Yajun , Yagi Yoshihiro , Moore Nicole J. , Dillon Heather E.
Published: January 2025

A cylinder in cross flow has been studied by many prior authors as a test case for computational fluid dynamics (CFD). We modified an existing case study for a cylinder in cross flow in an open source CFD program. Once the CFD model was working, we developed a physics-informed machine learning version for benchmarking. The machine learning code was validated using two existing sets of data from the literature for other systems.

Our research question is focused on understanding how well a physics-informed neural net for the Navier Stokes equations represent the behavior of complex flow around a cylinder. After the neural net model was validated, we used data from the CFD tool for a cylinder in cross flow to test the performance of the neural net. We compared velocities and stream functions to the original CFD solution to assess performance.

The results indicate the physics-informed machine learning model is computationally efficient and accurate for predicting the basic flow shapes. The number of training data points is very important for predicting major flow behavior. The machine learning model did not perform well for transfer learning in our study, failing to predict the key wakes. Future work will confirm how responsive the machine learning model is to variations in the input data, and different methods of providing a sparse training set.
Framework and Curricular Implementation of Technical Communication in an Undergraduate Mechanical Engineering Program
Authors: Van Poppel Bret P. , Londner Edward , Banko Andrew A. , Eils Colleen G. , Hoyer Brodie K. , Katalenich Scott M. , Zifchock Rebecca A.
Published: January 2025

This paper describes a mechanical engineering curriculum that is designed to improve student Technical Communication (TECOM). The curriculum is based on a comprehensive model of TECOM that includes guidelines for communicating effectively, three philosophies of professional communication, and three modes of communicating technical information: writing, presentation, and standalone visuals. Core cross-department classes within the curriculum introduce TECOM fundamentals, while the mechanical engineering program reinforces these fundamentals, culminating in a year-long capstone experience. All of these activities are integrated with the institution’s writing development program. Here, the authors present program improvements, proposed initiatives, and new courses under development.
Modeling Lignocellulosic Pyrolysis: An Integral Approach to the Thermal Degradation of Corn Cob and Product Prediction
Authors: Gómez Vásquez Rafael David , Bula Antonio , Mendoza Fandiño Jorge Mario , Camargo-Trillos Diego A. , Rhenals Julio Jesús David , Bonilla Gracia Samuel Iván , Arrieta Almario Álvaro Ángel
Published: January 2025

This study investigates the catalyzed pyrolysis of corn cob as a lignocellulosic biomass, aiming to enhance understanding of thermal decomposition and optimize the production of bio-oil, non-condensable gases, and char. Utilizing a detailed kinetic model adjusted with experimental data, it accurately predicts the impact of operational conditions, such as temperature and heating rate, on the quality and quantity of the products. The model’s validation, achieved by comparing its predictions with existing experimental results, confirmed the reliability of the approach. This research not only provides valuable insights for optimizing biomass pyrolysis but also lays a solid foundation for the design of more efficient thermochemical processes, contributing to the sustainable production of energy and chemicals from renewable resources. Significant findings include notable increases in the production of H2, CO, and CO2 within the 650°C to 950°C temperature range, while CH4 production remained relatively constant. The study also observed a peak liquid yield at 70% under optimal conditions, decreasing due to cracking effects, and highlighted the critical role of pyrolysis temperature in maximizing conversion efficiency. The developed model emerges as a crucial tool for process optimization, emphasizing the importance of biomass conversion research in advancing renewable energy solutions and the circular economy. The work not only provides valuable insights into the thermal behavior of corn cob but also offers a framework for exploring the pyrolysis of other biomass types, promising a significant impact on the development of efficient thermochemical conversion processes emphasizing the importance of biomass conversion research in advancing renewable energy solutions and the circular economy.
Immunoaffinity-Enhanced Lateral Filtration Microdevices for Rare Cell Isolation
Authors: Zhang Yang , Chen Kangfu , Chubb Madison L. , Greer Beate , Lagmay Joanne , Fan Z. Hugh
Published: January 2025

Sarcoma is a group of cancers that develop from bones or soft tissues. Among them, osteosarcoma (OS) and Ewing’s sarcoma (EWS) are the most common for children and young adults. While the majority of cancer death is due to metastasis, burgeoning evidence shows that circulating tumor cells (CTCs) are able to detect metastasis and help understand its process. However, isolation of CTCs is hindered by their extreme rarity and heterogeneity. The ratio of CTC to healthy blood cells is often in 1 : 106 – 107 in peripheral blood. Moreover, CTCs are different from each other in phenotypical and genetic characteristics, size, and shape. Microfluidic devices have been shown promising for rare cell isolation due to their high sensitivity and selectivity. We report a lateral filter array microfluidic (LFAM) system for analysis of sarcoma CTCs. The LFAM system enumerates CTCs based on both filtration and immunoaffinity. With antibodies against cell surface vimentin (CSV) and ganglioside 2 (GD2) coated on the surfaces of the microfeatures in the devices, the LFAM system offers capture efficiency up to 99.2%. This work helps understand filtration, the effects of filter size and flow, and immunoaffinity enhancement on CTC isolation for liquid biopsy.
Experimental Characterization of Compressed Air Nozzles
Authors: Park Deokgeun , Roller Jonathan , Kim Taeksoo , Barad Digvijaysinh , Rasmussen Bryan P.
Published: January 2025

Compressed air systems, often termed the “fourth utility” in industrial plants, are significant consumers of electricity. Focusing on end use cases where conventional nozzles are replaced with engineered nozzles has potential for energy reduction in compressed air systems in the industry. Engineered nozzles leverage the Coanda effect to entrain ambient air into the airflow from the compressor, thereby reducing the compressor’s load and achieving energy savings. In this study, flow rate and force of air from conventional and engineered nozzles across various operating pressures are quantified through experimental analysis. Quantification of nozzle type on the compressed air energy usage motivates facilities to use efficient nozzles for blowoff applications. Efficient nozzles then lead to energy savings through compressed air setpoint pressure and volumetric compressed air consumption reductions. The economic and environmental benefits of transitioning to efficient nozzles for industrial blowoff applications will be seen both for the facility as well as for the grid.
Fostering Critical Thinking and Practical Skills Development Through Hands-on Projects in Mechatronics, Robotics, and Machine Learning: A Focus on Two Case Studies
Authors: Cooper Brian , Przechocki Charles , Chauhan Vedang D.
Published: January 2025

Hands-on projects focused on real-world challenges play a pivotal role in engineering education, fostering critical thinking and problem-solving skills. This paper showcases two mechatronics, robotics, and machine learning projects that bridge the gap between theory and practice, equipping students with practical experience for future industry roles.

The first project centers around a machine learning-based pipe inspection robot designed to navigate small-diameter, lengthy tubes. By utilizing image processing and machine learning, the compact robot captures high-quality images using a phone-mounted setup, enabling effective quality assessments within a 6-inch diameter.

The second project, the Terrain Titan, offers versatility for applications like search and rescue and environmental monitoring. It incorporates a robust communication system for real-time data exchange using nRF24L01 modules, along with a sophisticated locomotion system capable of traversing diverse terrains. The addition of a manipulative arm, guided by an MPU6050 sensor for balance, enhances the robot’s capability for complex tasks.

Detailed development information, including CAD models part lists, programming code, is provided for both projects, facilitating replication and adaptation in educational settings. The projects enhanced students’ problem-solving skills through the development of technical competence, collaborative problem-solving, and adaptability. These findings demonstrate the effectiveness of hands-on projects in engineering education for fostering critical thinking and problem-solving skills.
Modeling Performance of Hybrid Thermionic-Thermoelectric Power Systems for Space Applications
Authors: Juette Elizabeth D. , Carey Van P. , Fleurial Jean-Pierre
Published: January 2025

Current radioisotope power system technologies for deep space applications rely on thermoelectric energy conversion to convert heat into electrical power. However, these thermoelectric materials are susceptible to damage in high temperature applications and are limited in their conversion efficiency. Thermionic energy conversion is an alternative form of direct energy conversion that operates most effectively at high temperatures. Due to advances in manufacturing techniques, thermionic technology is being revisited as a practical energy conversion technology with comparable performance to modern thermoelectric technology. A cascaded system incorporating both thermionic and thermoelectric energy conversion technologies can reduce the strain on the thermoelectric materials while increasing the overall power conversion efficiency for space power systems. The purpose of this investigation is to explore, through modeling, how a hybrid conversion system of this type might be optimized using modern technologies for each of the two types of subsystems.

To construct the system-level model we developed component-level, physics-based models and integrated them appropriately into a cascaded system. The thermionic model used in this study includes a more accurate accounting of space charge effects than used previously. This model includes the effects of back-emission and both emitter and collector electron reflection and the subsequent effect on output current density. This modification allows for improved performance prediction across a broad spectrum of emitter and collector temperatures. The hybrid model was used to explore strategies for maximizing hybrid performance within the temperature limits of the expected components. Thermionic and thermoelectric systems alone have typically achieved a conversion efficiency in the 5–10% range for typical heat input and rejection temperatures. Our modeling indicates that a hybrid system combining thermionic technology with the currently available thermoelectric energy conversion technologies could increase the beginning-of-life power output from a pure system efficiency of 5% to a hybrid system efficiency above 30% for input temperatures between 900 K – 2500 K and heat rejection at 300 K.
Engineering Ethics Principles and Design Justice Principles: Are They the Same or Different?
Authors: Das Shuvra
Published: January 2025

When we devise solutions to challenging design questions, quite often we do not consider the possibilities of the harms it may cause, and frequently exclude the voices of the very people who are affected by the design. The Design Justice movement is a network of design practitioners, artists, engineers, design educators and others from a variety of different backgrounds who want to change the design landscape into a more inclusive ecosystem.

Design Justice is an emerging field that seeks to address the ways in which design practices and decisions can perpetuate or challenge systemic injustices. Design Justice practitioners work to ensure that design is accessible, inclusive, and equitable for all. The principles of design justice are a very useful tool for infusing Diversity, Equity, and Inclusion concepts into the undergraduate curriculum. To some the design justice principles may seem similar or the same as the engineers’ code of ethics that are taught to and followed by all engineers. In this paper we examine the two sets of principles and try to find out the similarities and differences between them. This is done through a case study using a real-life problem. Students in multiple classes are tasked to analyze the case using the two sets of principles to determine an appropriate course of action. After that, they are asked to reflect on how their action decisions are similar or different when one set of principles are used versus the other. Through these reflections and the action decisions conclusions are drawn about the two sets of principles. We find that the students’ action decisions are quite different when they are using one set of principles versus the other. This case study was used in multiple courses and with multiple audiences and the results are reported and discussed in this paper.
Investigation of Pre-Bent and Pre-Curved Needles Interacting With Soft Tissue Materials
Authors: Kim Doyoung , Podder Tarun K. , Hutapea Parsaoran
Published: January 2025

Precise needle insertion is crucial in minimally invasive procedures such as brachytherapy, biopsy, and drug delivery, directly impacting clinical outcomes. Several factors affect needle positioning accuracy, including insertion force, tissue deformation, and obstacles along the trajectory. Techniques to activate needles to bend during insertion are being developed to create curved paths and avoid obstacles for targeting accuracy. However, the interaction between bent or curved needles and soft tissues has yet to be studied extensively. This study uses passive needles to understand active needle mechanics in soft tissue. Four needles are designed with pre-bent and pre-curved shapes with bent angles of 15° and 30°. Experiments are performed to measure insertion-extraction forces and needle deflection in tissue-mimicking phantom. The needle tip paths are evaluated using a video tracking analysis technique. Results show that the difference between bent and curved shapes minimally affects the target position and behaviors of forces and moments but significantly influences insertion and extraction paths. Tip tracking analysis reveals angle and shape impacts on path variations, with the highest average of 61.6% and 51.5%, respectively. Transverse-axial force ratios increase with angle by 59.3%, affecting moments during extraction. Paying attention to moment behaviors is essential since they are considered to affect the insertion-extraction path and different force distributions during insertion and extraction. Also, it could influence the damage and deformation of the tissue. This study provides a fundamental understanding of the mechanical behavior of deflected passive and active needles advancing in soft tissues to improve the design of surgical needles for minimally invasive procedures.
Solidification of Cyclohexanol in Sublimation Drying for Enhancing Semiconductor Manufacturing: Experimental and Mathematical Studies
Authors: Xu Minghan , Mohit Mohammaderfan , Hanawa Yosuke , Zhang Jianliang , Yoshida Junichi , Sawada Koichi , Sasaki Yuta , Sakuma Atsushi , Sasmito Agus P.
Published: January 2025

Solidification is a ubiquitous process that is critical in various industries, including semiconductor manufacturing. While extensive research exists on mechanical aspects of sublimation drying, the impact of non-uniform crystal morphology during solidification remains overlooked. This study addresses this research gap by focusing on the solidification behavior of cyclohexanol, a common sublimation chemical, crucial for preventing nanostructure collapse in semiconductor devices. A thermally controlled experimental chamber facilitated investigation into cyclohexanol solidification, employing high-speed cameras, thermocouples, and advanced image analysis. A unified mathematical model using the Stefan condition was developed. Experimental and simulated results were compared with respect to temperature profile, demonstrating good agreement. The presented framework offers a comprehensive approach for analyzing sublimation drying thermally, with potential applications beyond cyclohexanol to other sublimation chemicals and their optimal conditions, thus advancing semiconductor manufacturing processes.
Bucket Loaders Using Adjustable Linkages
Authors: Vudutanaboina Ritvik , Zhou Hong
Published: January 2025

Bucket loaders or payloaders (also known as front loaders or loaders) are machines that are commonly employed in construction, mining or landscaping projects for loading or moving debris, soil, sand, or rock. Wheeled bucket loaders are preferred in most situations because of their high speed, efficiency and flexibility, relatively low weight and operation and maintenance costs. Tracked bucket loaders are chosen due to their high surface traction, stability and maneuverability, better performance on uneven or rough terrain, and relatively less ground impact. A payloader uses its front bucket to scoop materials that are stacked on the ground, and then either transport them to a different location or load them to a waiting transportation truck. The front bucket is pivoted to the end of the boom of the loader. The tilting motion of the bucket is generated by its corresponding hydraulic cylinder through a four-bar linkage. The boom link is connected to the chassis of the payloader using a revolute joint to lift or lower the bucket. The boom link has its driving hydraulic cylinder and its related driving linkage. The arm of a payloader consists of its bucket and boom, which moves the bucket to fulfill the payloader’s function. The position and orientation of the front bucket are determined by the joint efforts of the bucket and boom driving cylinders together with their driving linkages. The axes of the revolute joints of a payloader arm are parallel each other, which leads to a planar motion of the front bucket. The planar workspace of the front bucket is defined by the dimensions of the driving linkages and the driving strokes of the cylinders. The existing payloaders usually have fixed workspace since their driving linkages are not adjustable and driving cylinders have fixed strokes. The fixed workspace of a payloader lacks operation flexibility and limits its applications. This research incorporates adjustable linkages into payloaders to enhance their operation flexibility. The motion performances of payloaders without and with adjustable linkages are analyzed, simulated, evaluated, and compared. The results from this research are tried to provide certain guidelines for improving operation flexibility of the existing bucket loaders.
Effect of Walking Speed and Asymmetric Loading on the Clinical Angles of Walking Gait
Authors: Caruntu Dumitru I. , Trejo Alfirio , Rodriguez Eric , Alvarez Barriga Camila T.
Published: January 2025

This study assessed the biomechanical impacts of different walking speeds and asymmetric weight bearing on gait dynamics, examining clinical angles, step length, and cycle times under four conditions using advanced motion capture technology. Findings indicated that both walking speed and carrying a 25-pound weight significantly affect gait mechanics, with fast walking speeds associated with shorter cycle times and longer step lengths, while added weight introduced notable variability in cycle times and altered gait stability. Polynomial fitting and averaging techniques highlighted variable consistency in gait patterns, particularly showing reduced uniformity under weighted conditions. The results emphasize the importance of tailored gait analysis in rehabilitation and athletic training, suggesting that accommodating variations in walking speeds and weight bearing can enhance mobility and stability, thus improving overall quality of life.
Microcracking Simulation of Silicon-Based Anode Sheet in Lithium-Ion Battery (LiB) Using Finite Element Method
Authors: Kawashima Yuzuki , Ogata Kazuma , Shibayama Yuto , Takagi Aoi , Yonezu Akio
Published: January 2025

Anode sheet of lithium-ion battery (LiB) has a layered structure consisting of an active material layer (composite of binder and active material) and a current-collecting layer (copper foil). Active material of silicon (i.e. silicon-based anode sheet) has been attracting attention in order to achieve high electric capacity of LiB. One of the problems in silicon-based anodes is cracking in silicon and binder due to the manufacturing process and cycle charging, leading to shortened battery life and reducing electrical capacity. Our previous study reports that microcrack occurs around Si particle (active material) due to the stress concentration under tensile loading. To avoid this problem, the microstructural design of the active material layer is required to further improve the performance and life of LiB. In this study, the damage criterion was employed to finite element method (FEM) in order to simulate crack initiation and propagation in binder with Si particles. The criterion used in this study is Oyane failure criterion which expresses ductile failure due to stress triaxiality (since, in principal, void nucleation is dominated by stress triaxiality degree). Due to non-linear plastic deformation of binder, this criterion is established based on accumulative strain increment. We simulated microcrack propagation in active material layer subjected to uni-axial tension. The validity of the crack simulation was conducted by comparison of actual experiment. Indeed, this study prepared several models with different particle positions and each simulated crack path was compared with actual one of SEM image.
Automatic Piping Routing Applying Multi-Objective Genetic Algorithm
Authors: Mogi Shunta , Uemichi Akane
Published: January 2025

Piping for fluid transport is essential in industrial plants. However, the design of piping requires an enormous amount of time. This paper presents an example of tool construction focusing on the total pipe length, interference with obstacles, seismic resistance, and the number of bends. The total pipe length, seismic resistance, and number of bends were used as objective functions. In contrast, interference with obstacles was used as a penalty function, and the sum of these functions was used as the overall evaluation index. The tool minimizes this overall evaluation index by multi-objective genetic algorithm (MOGA). The piping layout information is expressed as a piping gene, representing the position of the piping bend coordinates. The piping genes are evolved through crossover and mutation by combining the A* search algorithm and MOGA to obtain a layout that minimizes the overall evaluation index. However, since gene crossover and mutation are generated stochastically, different final layouts are obtained from trial to trial. This paper performed several examples with fixed starting and ending points in the piping routing space.
Methodical Approach to Instance-Specific Reliability Modeling for the Perpetual Innovative Product in the Circular Factory
Authors: Leitenberger Felix , Dörr Matthias , Gwosch Thomas , Matthiesen Sven
Published: January 2025

The Circular Factory reprocesses used products into current-generation products, aiming for perpetual innovation. This requires predicting the reliability of a product’s components and subsystems throughout its use life. Each product within the Circular Factory exhibits unique life cycles and processes, necessitating instance-specific reliability models.

This study introduces a novel methodical approach for reliability modeling tailored to the challenges of the Circular Factory, illustrated through a case study on angle grinders. The approach consists of four steps: Developing a non-parametric system reliability model by identifying failure types and assessing their impact; Generating reference data by sensor-integrated products and by X-in-the-Loop test benches; Integrating instance-specific data such as historical loads, tolerances, and material into reliability models; and validating these models at both subsystem and system levels to ensure they accurately reflect expected system reliability. Machine Learning techniques are proposed to enhance model accuracy and to challenge instance-specific reliability challenges.

Critical questions emerged from the theoretical case study, highlighting the necessity for more in-depth investigations. Future work will involve experimental validation of these models, continuing the study’s contributions to the Circular Factory paradigm.
The Crucial Role of Critical Thinking in an Integrated Approach to Machine Design Problems
Authors: Dhanasekaran Puttagounder
Published: January 2025

Engineering technology students are expected to focus more on applied and hands-on learning, gaining practical knowledge that aligns with industry needs. The industry seeks graduates who are prepared for day-to-day work and well-versed in applied engineering and industry applications. It is beneficial for technology students to engage in problem-solving in machine design using an integrated approach, which exposes them to real-time circumstances in the industry. While students are taught how to design mechanical elements such as shafts, gears, bearings, etc., individually, it is equally essential for them to understand how to integrate these elements into systems or sub-systems. Example problems will be discussed to illustrate how each machine element interacts with other machine elements, aiding students in designing a cohesive system. In an integrated design approach, the output of one machine element serves as input to another, creating a continuous flow of information. An example problem will be presented with minimal inputs, requiring students to devise solutions by selecting appropriate factors that align with industry requirements to solve the problem. They will be encouraged to articulate their thought process behind these selections. Since the industry relies heavily on adhering to industrial standards, students must cite relevant standards in each design decision, drawing from what they learned during their classroom exercises. This approach requires a significant amount of critical thinking, as students must justify their assumptions when addressing various aspects such as the selection of driven machinery, duty cycles, and work environment conditions. Considerations such as stress concentration factors, bearing span and lifespan, interference between machine elements, and selecting appropriate tolerances are crucial. This paper focuses on the integrated problem-solving method and highlights the essential critical thinking requirement in engineering technology education.
Experimental In-Field Evaluation of HVAC Fault Detection and Diagnostics Technologies
Authors: Patil Prathamesh , Gorthala Ravi
Published: January 2025

Energy efficiency of heating, ventilation, and air conditioning (HVAC) equipment is challenging to upkeep, maintain, and repair without a comprehensive maintenance plan, and experienced personnel. With the prevalence of HVAC Fault Detection and Diagnostic (FDD) tools that aim to address issues in HVAC energy efficiency, these tools collect real-time system data and provide a variety of fault detection and diagnostics that may improve the energy efficiency, operational life, and reduce maintenance costs of the equipment. By detecting and diagnosing soft mode faults before they develop into catastrophic hard faults, FDD tools serve as a continuous and preventative maintenance tool. In determining their effectiveness in-field, 9 commercial FDD tools were paired with 9 packaged roof-top unitary systems (RTUs) that are independently verified through an industrial-scientific monitoring system that measures both the two-stage vapor compression circuits, and air-side psychrometric performance of the equipment. After collecting the data and monitoring the equipment and tools for three years, three refrigerant charge events were observed and compared to their Energy Efficiency Ratios (EER) before and after system repairs. Two tools detected and diagnosed low charge faults on Sites 1 and 2, which respectively increased and decreased long-term EERs from 6.3 to 9.1, and 10.3 to 9.2. This is because Site 1 had an initially low charge that was not diagnosed due to an improperly installed pressure transducer, which was later identified until a pinhole leak on the evaporator coil signaled a maintenance event. The second FDD tool for Site 2 after two sequential leaks through pressure transducer fittings was not sensitive enough to diagnose the leak earlier until a significant amount of charge had evacuated. The third FDD tool on site 3 did not detect and diagnose a high charge fault that led to a decrease in EER from 16.6 to 15.3. Contrary to claims supported by some of the FDD tools, these tools are only effective with expert level supervision.
A Simulation Tool to Evaluate Different Capture Strategies in a Berthing Maneuver
Authors: Sorli Davide , Ferrauto Martina , Melchiorre Matteo , Palmieri Pierpaolo , Salamina Laura , Mauro Stefano
Published: January 2025

Space operations for satellite maintenance and space debris capture necessitate meticulous design and planning of contact maneuvers, which may include docking or berthing operations. Minimizing contact forces between the chaser and the target is crucial to prevent undesired repulsion or excessive torque demands on the chaser’s attitude control system. Various design parameters such as capture strategy, relative speeds, stiffness of components, and force directions influence these maneuvers.

The MUSAPOEM project aims to develop a comprehensive simulation environment for analyzing and designing proximity operations. It focuses on modeling the initial contact phase between spacecraft using a robotic arm for target capture. The simulation tool incorporates detailed models of both spacecraft, of a seven-degree-of-freedom manipulator, and of their mechanical interfaces, with particular attention on the modeling of contact mechanics.

The paper explores different capture maneuvers, evaluating the impact of capture strategy and robot motion planning on the chaser. Simulation results discuss exchanged forces, relative spacecraft motion, energy consumption by the robotic arm and the GNC during the maneuver. Additionally, the robustness of the system is tested throughout various maneuver simulations.
Numerical Investigation of Flow Field and Mixing Efficiency in the Kanbara Reactor
Authors: Razzak Mohammed Abdul , Guo Xipeng , Imran Syed , Walla Nicholas , Yin Hongbin , Zhou Chenn
Published: January 2025

The Kanbara Reactor stands as a cornerstone desulfurization technology in the hot metal pretreatment refining process, widely embraced in modern steelmaking. Immersing a mechanical stirring mechanism directly into the reactor utilizes a specially designed impeller to induce turbulent mixing within the molten steel. This study employs a comprehensive three-dimensional multiphase Computational Fluid Dynamics (CFD) model to simulate the flow field within an industrial-scale Kanbara Reactor. Leveraging the Volume of Fluid (VOF) approach and sliding mesh technique, the model accurately captures the rotating flow dynamics. Validation against experimental data yields a mere 3.12% average discrepancy for vortex depths. Simulations explore the influence of Impeller Rotation Speed (IRS) on various parameters, revealing notable increases in average velocity, intensified recirculation patterns, and deepened vortex cores with rising IRS. Particularly, surface velocity peaks and stabilizes as the centripetal force-induced depression reaches its maximum extent. Furthermore, the simulations provided detailed insights into the industrial-scale Kanbara Reactor’s multiphase distribution data exposed the spatial arrangement of different phases within the reactor, while the flow field distribution describing regions of high and low velocity. The distribution of desulfurization particles, specifically lime, served as a crucial indicator of the mixing phenomena, revealing dispersion patterns throughout the molten steel bath. These findings offer valuable insights for reactor design optimization and operational enhancements, ultimately enhancing mixing and desulfurization efficiency in steelmaking processes.
Calibration and Inspection of Additive Manufacturing With Laser Profilometry
Authors: Elliott Sam , Campbell Matthew I.
Published: January 2025

Additive manufacturing has drastically reduced the time it takes to fabricate unique parts, which is why it is frequently used for prototyping and low-volume production. However, it is not effectively utilized for modification or repair of existing parts. This paper presents a proof-of-concept method for using a combination of scanning technology and 3D printing to scan a desired print area, determine the geometry to be printed, and print directly onto an existing surface. This is achieved using a laser profilometer to scan a real-world object that is compared with an existing virtual representation of the object in CAD. The real surface and the simulated surface are aligned using the Iterative Closest Point algorithm, and then subtracted from each other to determine any discrepancies between the real model and the simulated model. These differences in the models determine the print volume, which is converted to print paths. The paths are printed using a custom 5-axis Fused Filament Fabrication printer onto the real surface. This method shows that scanning and additive technology can be utilized together to expand the capabilities of 3D printing to encompass repair and alteration of parts. In this paper, we demonstrate the algorithm behind this proof-of-concept method in which a test part with a fabricated defect is scanned and repaired.
Hybrid Locomotive Consists: Balancing Operational and Embodied Carbon Effects
Authors: Agyapong Beatrice , Oldknow Kevin , McVey Molly
Published: January 2025

In this paper, the authors present an analysis of wheel and rail wear intensities corresponding to representative cases of tractive and regenerative braking efforts associated with Diesel Electric Locomotives and Battery Electric Locomotives (respectively) in a Hybrid Consist arrangement. Relative changes in wheel and rail wear intensities are simulated for a practical set of operating (curving) conditions, with wear energy (T-gamma) levels used to estimate the change in relative contribution of the locomotive consist to wheel and rail wear rates, by placing the results in the context of established wheel and rail wear models. Wear rates are then translated into estimates of embodied carbon footprint, which can be used in a lifecycle modelling approach through which the combination of tractive effort and regenerative recharging can be optimized to yield a balance between operational carbon savings and embodied carbon emissions.
Electrospun Silica Nanofibers as Passive Thermal Control Materials for the Extreme Environment of Low Earth Orbit
Authors: Ibekwe Chieloka , Wang Xuanjie , Hartwig Jason W. , Feller Jeffrey R. , Swanger Adam M. , Narayan Shankar
Published: January 2025

Effective thermal management is crucial for maintaining spacecraft and onboard systems at optimal temperatures, ensuring their longevity in space missions. Passive thermal management is particularly promising due to its lower power consumption compared to active systems. This study focuses on developing materials with low solar absorptance and large thermal emittance to facilitate self-cooling under the harsh thermal conditions of space. We employ electrospinning, a nano/micro-manufacturing technique, to create a lightweight, fibrous thermal control material from silica (SiO2). Using scanning electron microscopy (SEM), we examine the nanoporous structure of the electrospun material. Its optical properties, including reflectance, transmittance, and absorptance across ultraviolet, visible, and infrared wavelengths, are assessed using spectrometers interfaced with integrating spheres. To test durability in space, we conduct high-temperature endurance and ultraviolet resistance tests to observe changes in optical properties of the materials and evaluate their performance in low Earth orbit (LEO). We also compare the material’s solar reflectance and thermal emittance to existing spacecraft materials. The findings suggest that electrospun silica nanofibers presents a new paradigm for passive thermal control in space applications.
Assessing Innovation and Commercialization of Faculty at a Historically Black College and University
Authors: Peebles Alex , Tyagi Pawan
Published: January 2025

While primarily established as teaching institutions, Historically Black Colleges and Universities (HBCUs) now offer graduate degrees and conduct a significant amount of research. However, HBCUs are behind their non-HBCU counterparts in the process of commercializing their intellectual property, or introducing their innovations to the market where it can be sold to the intended end user. Our goal is to understand the interest and challenges that faculty at HBCUs face in the process of generating and commercializing intellectual property. Here, we present preliminary findings of a survey sent to faculty members in the School of Engineering and Applied Sciences at the University of the District of Columbia. Eleven faculty members responded to the survey, representing the departments of Mechanical Engineering, Civil Engineering, Electrical and Computer Engineering, and Computer Science and Information Technology. Seven (64%) respondents reported that they have developed intellectual property which they believe has commercial potential, however only three respondents (27%) have successfully commercialized their innovations. Respondents reported that the resources available to them for commercialization were either “missing” or “lacking”, and that they had low involvement with industry partners. These results show that HBCU faculty are generating intellectual property but feel stuck commercializing. Investing in the technology transfer offices of HBCUs will spark growth and improve the impact of these important institutions.
Constitutive Modeling of Nonlinear Time-Dependent Mechanical Properties Using Molecular Dynamics Simulations
Authors: Uddin Md Salah
Published: January 2025

Polymeric systems have wide applications in engineering domains such as aerospace, automobile, biomedical, sports goods, packaging, electronics and optics, and energy sectors. These materials exhibit hyperelastic and time-dependent responses such as relaxation and strain-rate-dependent elasticity. Finite element analysis of polymeric components requires material properties for different constitutive models that are obtained from experimental results at the coupon level. Molecular dynamics (MD) simulations can be used to simulate these responses, however, the time and length gap is a challenge to overcome. MD simulations are conducted for a very short time, e.g. nanoseconds to femtoseconds which overestimates the mechanical properties. This study develops a bridging technique for time and predicts stress-stress strain response for cyclic loading at experimental frequency using MD simulations results conducted at high frequency. Molecular models are deformed under cyclic loadings at three different frequencies. Four different strain amplitudes are applied at one frequency. A dimensionless time parameter is introduced and the profile for stress amplitudes transformation to experimental level is predicted. Assuming an underdamped system, the decaying of stress amplitude over time and phase difference is calculated. Experiments are conducted for cyclic loadings of up to three different loads. The prediction agrees well with the experimental results.