bluuebunny/crossref_metadata_2025_split huggingface dataset:
Vortex Characterization of Rotor-Stator Cavities Dominated With Radial Flows
Authors: Reddy S. N. Dileep Bushan , Singh Praveen Kumar , Nayak Kali Charan , Scanlon Tim 
Published: February 2024

Abstract
Rotor-Stator cavities are quite common and an important feature in the turbomachinery application. The static pressure and total temperature change in the rotor-stator cavities play a critical role in the design of the secondary air system, bearing load and component life. Hence understanding the vortex characteristics and windage heating is vital to accurately estimate the swirl velocity, static pressure, and air temperature surrounding rotor/stator structures. This paper describes the development of a numerical methodology aimed at studying the vortex dynamics and windage heating in rotor-stator cavities. Specifically, a 2D axisymmetric validated CFD model is developed utilizing commercial finite volume-based software incorporating the Reynolds Stress turbulence model. Using the validated model, a broad parametric study is conducted by varying the aspect ratio of the cavity, inlet swirl fraction and mass flow rate at a constant rotor speed. Finally, the radial variation of swirl velocity, static pressure and total temperature are studied for the radial inward and outward flows. The nature of the vortices is found to be very complex and they cannot be categorized into either free or forced vortex. The vortices change radially in the cavity with change in the flow, inlet swirl and cavity aspect ratio. Practically it is difficult and cumbersome to arrive at a universal characteristic equation for the range of flow conditions for a cavity of interest. In this paper an attempt is made to arrive at the universal characteristic equation using machine learning based surrogate model for the rotor-stator cavity. A polynomial regression is developed using the CFD generated data sets by suitably training and testing the model. Feature engineering and hyperparameter tuning techniques are used to select the important features from the input parameters to make the model simple without significant accuracy loss. The results from the surrogate model show accuracy of 97% with an independent set of CFD data used in validation. Understanding of the vortex dynamics from CFD and the polynomial vortex characteristic equations will be instrumental in the design of secondary air system, bearing load and component life in turbomachinery.
Methodology to Optimize the Location of Osteosynthesis Material for 3D Printed Cranial Implants Based on Force Analysis
Authors: Perero Segarra Bryan S. , Helguero Carlos G. , Maldonado Fausto , Amaya R. Jorge Luis , Saldarriaga Carlos , Loayza Francis 
Published: February 2024

Abstract
Cranioplasties are highly complex surgical processes where surgeons try to repair skull bone defects in patients. An aspect that needs to be addressed in this procedure is the precise location of osteosynthesis material, such as screws and plates, for successful implant fixation. These must meet the technical requirements and biocompatibility with the organism to avoid rejection. Currently, the positioning of the anchor points (A.P.) is exclusively based on the surgeon’s expertise, and there are no precise measurement tools or any criteria for the accurate location of this fixing material, depending on the patient’s case. This work proposes a method to establish where the A.P. will be located before surgery, reaching their maximum resistance in service using a mathematical tool to define the location of the osteosynthesis material. This study reduces the time in surgery, ensuring its correct positioning and behavior against specific loads using indentation guides designed according to the patient’s case before admission to the operating room. Information based on a cranial implant case study was obtained to determine the maximum impact force the system would withstand. The validation was done by simulation showing the general behavior before an external stimulus with previously defined A.P.
A Travelling Wave Ferro-Microfluidic Device Platform for Potential Cell Separation and Sorting
Authors: Hewlin Rodward L. , Edwards Maegan 
Published: February 2024

Abstract
This paper presents the design and development of a simple traveling wave ferro-microfluidic device platform and rig purposed for the potential manipulation and magnetophoretic separation of cells in water-based ferrofluids. This paper details in full the development of the ferro-microfluidic device for potentially separating cells and magnetic nanoparticles as well as the design and development of a system rig for producing the electric field within the ferro-microfluidic channel device for magnetizing and manipulating nonmagnetic particles in the ferro-microfluidic channel. The results reported in this work demonstrate proof of concept for magnetophoretic manipulation and separation of magnetic and non-magnetic particles within a water based ferrofluid confined in a simple ferro-microfluidic device with a programmable chip platform.
Thermal Analysis of Thermosyphon for Waste Heat Recovery From Auto Exhaust Using Limited Fluid Charge
Authors: Xiao Bin 
Published: February 2024

Abstract
An experimental investigation was carried out to analyze the thermal performance of a thermosyphon that recovers waste heat from automobile exhaust using a limited fluid charge in this study. The thermosyphon was constructed from Inconel alloy 625. The outer diameter of the thermosyphon measures 27 mm, with a thickness of 2.6 mm, and an overall length of 483 mm, which includes a 180-mm evaporator, a 70-mm adiabatic section, a 223-mm condenser, and a 97-mm finned exchanger. The study involved directing exhaust gas onto the evaporator end cap at a flow rate ranging from 0–10 g/sec, with temperatures varying from 300–900°C. The impact of three parameters, namely the inclination angle (ranging from 5°–45°), water mass (ranging from 2 g–5.3 g), and the amount of non-condensable gas Argon (ranging from 0 g–0.6 g), were analyzed to determine their effects on the thermal performance of the thermosyphon. Based on the experimental results, it was observed that when the thermosyphon contained 3 g of water and 0.0564g of argon, the condenser achieved a maximum temperature of approximately 200°C. The optimal fuel loading rate for the thermosyphon lies within the range of 0.2 g/s to 0.7 g/s. Furthermore, outer wall temperatures of the thermosyphon increase as inclination angles increase due to the explicit expansion of the actual heating area within the evaporation section of the thermosyphon, accompanied by an augmented gravitational component of the water flux. An increase in the quantity of non-condensable gas (NCG) can diminish temperature gradients on the outer wall of the thermosyphon, leading to a reduction in the thermosyphon’s performance. The insulation applied at the adiabatic section proved effective in increasing temperature gradients on the outer wall of the thermosyphon and thereby enhancing the performance of the thermosyphon. With an increase in the water charge within the thermosyphon, heat transfer rates from the exhaust to the thermosyphon and from the thermosyphon to the fuel increase.
Collapsible Origami-Based, Drop-Deployable Micro Air Gliders
Authors: Kolano Hannah , Lao Miranda , Patel Anil , Wei Maxmilian , Xu Jingyi , Lee Christopher L. 
Published: February 2024

Abstract
This paper reports on the design, fabrication, and testing of two micro-air-vehicles (MAVs) with origami-based fixed wings which were inspired by foldable wings found in nature that are not controlled by muscles but by joints that have bi-stable open-closed positions. The wings have a folding pattern that allows them to collapse and expand via flexible joints. The first MAV was designed to land quickly in a controlled manner while the second was designed to glide over a longer period of time. Both wing configurations were designed so that the MAVs can be stored and deployed in compact form by minimizing their wingspan. Upon release, the wings self-reconfigure enabling the MAVs to fly. Flight tests were conducted to evaluate the performance. Both qualitative and quantitative results are presented that evaluate gliding capability. Qualitative evaluations describe how well the MAVs level out from a vertical to horizontal position and the straightness of their flight paths. Quantitatively, the time the MAVs took to level out and then to land on the ground was recorded. The flight tests demonstrate that the prototypes can be deployed in a collapsed configuration then open successfully and glide to the ground.
CFD With Fluid Structure Interaction Analysis of Lung Alveolar Sacs and its Applications in Emphysema Study
Authors: Carotenuto Carlo , Orlandi Francesco , Montorsi Luca , Milani Massimo 
Published: February 2024

Abstract
Emphysema, a chronic lung disease characterized by respiratory distress and reduced lung function, poses significant challenges. Computational Fluid Dynamics (CFD) coupled with fluid structure interaction (FSI) is a highly effective simulation technique that offers valuable insights into the mechanics of lung function and the influence of diseases like emphysema. The intricate lung alveolar sacs play a vital role in gas exchange, and CFD with FSI enables the simulation of mechanical forces that shape and impact their functionality. By employing CFD with FSI, we can simulate the fluid dynamics of emphysema and acquire a comprehensive understanding of disease progression. These simulations allow us to explore the contributions of tidal breathing and surface tension forces. This study has demonstrated through FSI that a lung alveolus affected by pulmonary emphysema, and therefore collapsed, causes reduced air intake with each breath. This is due to the significantly compromised deformability of the alveolar wall. Ultimately, this technique plays a critical role in developing therapeutic interventions to improve patient outcomes.
An ANOVA Based Study of Variations in Circularity Form Error Due to Mathematical Methods and Measuring Instrument Eccentricity
Authors: Sahay Chittaranjan , Ghosh Suhash , Venkatesh Nithish Adhithya 
Published: February 2024

Abstract
One of the most important fundamental forms for engineering components is the circular cross-section. Circular forms arise in many applications, particularly in bearing surfaces such as rotating shafts and ball bearings. The importance of studying roundness form deviations of circular and cylindrical features is to avoid the excessive lateral or axial runout deviations of the rotating and reciprocating parts during dynamic operations. Of all the methods of measuring these form errors, the most precise is the one with accurate spindle and turntable type measuring instrument. Considering the precision that industries require now and will require in the future, the authors of this article have chosen roundness (also called circularity per ASME Standards) as the measurable parameter. Based on reference circles, this paper focuses on the four modeling methods of roundness, namely, (1) Least Squares Circle (LSC), (2) Maximum Inscribed Circle (MIC), (3) Minimum Circumscribed Circle (MCC) and (4) Minimum Zone or Minimum Radial Separation (MRS) Circles. In this article, the authors have conducted an ANOVA (Analysis of Variance) study of variations in roundness measurements based on these mathematical methods, instrument’s centering and tilt error (also known as eccentricity) and filter type and filter size. In order to arrive at precise results, the roundness of a near-to-perfect cylinder is measured at selected heights on an accurate spindle and turn-table type measuring instrument, Mahr MMQ200. Other instrument settings, namely, probe size and probe angle were kept the same throughout. This statistical investigation provides key insights to determine the variances due to the different sources of variation and determine the percentage contribution due to each source. This helps the instrument users to pay close attention to the variables that would influence the final results the most, leading to develop a better control in the beginning of the measurement process.
Improvements to a Friction Stir Extrusion Machine
Authors: Emblom William J. , Antoine Ethan , Dartez Zachary , Faucheaux John , Hendrix Stephen , Simon Austin , Theriot Blake , Darby Paul , Wagner Scott W. 
Published: February 2024

Abstract
Friction stir extrusion is a variation of friction stir processing, of which the most well-known is friction stir welding where a non-cutting rotating probe comes into contact with two metal sheets or plates. For friction stir welding, the friction between a rotating probe and the two metal sheets generates heat so that the temperature of the sheets increases above the recrystallization temperature and the material of the two metal sheets are stirred and upon cooling, results in a joined sheet. Within the stir zone, the grain structure is an ultrafine.
For friction stir extrusion, the rotating probe is plunged into a work piece and the resulting heat raises the work piece to above the recrystallization temperature as either a solid or hollow cylindrical rod is formed.
The previous version of the custom-built machine friction stir machine had significant vibration present during tests, difficulty in mounting the tooling on to the machine, errors in the workpiece temperature readings, alignment of the probe and work piece, and other manufacturing defects that made the machine difficult to be used for research and testing.
This paper documents improvements to the friction stir machine and provides preliminary test data prior to a full-scale investigation of friction stir extrusion processes. Data in the paper includes observations, pictures, and force and temperature results.
Turbulent Heat Transfer From an Isothermal Half-Cylinder Positioned Parallel to Airflow
Authors: Rarick Nathan A. , Molki Majid 
Published: February 2024

Abstract
Turbulent heat transfer and fluid flow characteristics for an isothermal half-cylinder oriented parallel to a uniform flow are investigated numerically. The computational results of the local and average heat transfer coefficients are compared with the available experimental data. The semi-circular cylinder, which has a length-to-diameter ratio of 1, is compared to full cylinders of similar dimensions. Though not identical, the current results agree with full cylinder axial flow analysis in that the convective heat transfer coefficient increases to its maximum towards the edge of the front face. Computations are carried out over a range of Reynolds numbers from 5,000 to 42,000, using air as the working fluid. Results showing the convective heat transfer coefficient distribution across each face and the influences attributed to flow separation and flow recirculation are presented. The Nusselt number at the stagnation point is compared with experimental results. No vortex shedding was seen, and a steady state flow condition was observed, contrary to that seen in cylinders in cross-flow. The k-ω SST turbulence model is implemented as adverse pressure gradient situations are expected. Contour plots of heat flux and plots of the local and average Nusselt numbers are provided as results.
Electro-Mechanical Studies of Multi-Functional Glass Fiber and Carbon Fiber Composites Exposed to Seawater/Freshwater and Cold Temperatures
Authors: O’Donnell Jacob , Cavallaro Paul , Smith Michael P. , Valm Nicholas , Legris Joseph , Warner Eric , Chalivendra Vijaya 
Published: February 2024

Abstract
A detailed experimental study is performed on the piezo-resistive damage sensing capability of electrically conductive carbon fiber and carbon nanotube-infused glass fiber composites after freshwater and saltwater ingression under quasi-static tension and under low temperatures. The electrical resistance is recorded via a two-point probe measurement technique for carbon fiber and a four-point probe measurement technique for glass fiber.
The carbon fiber composites on average absorbed 1.7% of their initial mass as either freshwater or saltwater. The glass fiber composites absorbed 2.1% on average of their initial mass as freshwater or saltwater. Mechanical and electrical properties of carbon fiber composites showed a dependency on both water ingression and testing temperature.
Water-infused carbon fiber composites exhibited a unique electrical behavior where, after severe delamination the frayed lamina fibers could bridge the delamination and regenerate lost electrical connections. Lower temperatures allowed more severe delamination to occur within the composite. The glass fiber composites infused with 0.5% by weight (wt) and 95% purity carbon nanotubes were not conductive and did not detect internal damages.
XTENTH-CAR: A Proportionally Scaled Experimental Vehicle Platform for Connected Autonomy and All-Terrain Research
Authors: Sivashangaran Shathushan , Eskandarian Azim 
Published: February 2024

Abstract
Connected Autonomous Vehicles (CAVs) are key components of the Intelligent Transportation System (ITS), and all-terrain Autonomous Ground Vehicles (AGVs) are indispensable tools for a wide range of applications such as disaster response, automated mining, agriculture, military operations, search and rescue missions, and planetary exploration. Experimental validation is a requisite for CAV and AGV research, but requires a large, safe experimental environment when using full-size vehicles which is time-consuming and expensive. To address these challenges, we developed XTENTH-CAR (eXperimental one-TENTH scaled vehicle platform for Connected autonomy and All-terrain Research), an open-source, cost-effective proportionally one-tenth scaled experimental vehicle platform governed by the same physics as a full-size on-road vehicle. XTENTH-CAR is equipped with the best-in-class NVIDIA Jetson AGX Orin System on Module (SOM), stereo camera, 2D LiDAR and open-source Electronic Speed Controller (ESC) with drivers written for both versions of the Robot Operating System (ROS 1 & ROS 2) to facilitate experimental CAV and AGV perception, motion planning and control research, that incorporate state-of-the-art computationally expensive algorithms such as Deep Reinforcement Learning (DRL). XTENTH-CAR is designed for compact experimental environments, and aims to increase the accessibility of experimental CAV and AGV research with low upfront costs, and complete Autonomous Vehicle (AV) hardware and software architectures similar to the full-sized X-CAR experimental vehicle platform, enabling efficient cross-platform development between small-scale and full-scale vehicles.
The Demonstration of a Low-Cost Tabletop Microscale Hydroforming System With a Self-Aligning Sealing System
Authors: Emblom William J. , Frederick Connor L. , Carline Grant R. , Earles Kenneth , Taylor Collin , Tran Diep , Cambre Brock , Castille Bradley , Olayinka Ayotunde , Darby Paul , Wagner Scott W. , Ferdowsi Farzad 
Published: February 2024

Abstract
A microscale/multiscale tube hydroforming tabletop test bed that includes the tabletop testbed, PLC controller, and high-pressure hydraulic pump has been developed. Currently, feedback and controls are being implemented along with adapting previously built open-die tooling as part of a collaborative initiative between researchers in Louisiana and at Michigan Technological University.
The tooling utilizes the floating die concept and was designed and built based upon conventional macroscale manufacturing processes to produce microscale components.
At this point in the system development, the objective is to implement controlled expansion of AISI 304 tubing with an OD of 2-mm using an existing floating rigid die. Later modifications to the system will allow the production of tubing with complex geometry such as tee-sections that can be used in microfluidic devices such as fuel cells, microscale heat exchangers, and MEMS.
Preliminary results for formed sample tubes are discussed.
Investigation of Frequency Coupling in a Restricted Pulsatile Flow
Authors: Barbosa Gonzalez Alexandra , Goldmann Felix , Ahmed Fadhil , Byers Clayton P. 
Published: February 2024

Abstract
A parametric study of the influence of flow restriction and Reynolds number on the acoustic spectrum is performed. By altering the boundary conditions of the pulsatile flow, changes in frequency coupling can be investigated. To mimic aortic valve stenosis in a resting heart, the pulsing frequency is set to 70 beats per minute (1.17 Hz), while the physical size of the restriction and fluid volume pumped is altered. An 8 × 8 data matrix is collected for different Reynolds numbers (4500–9831) and restriction severity (0–82% restricted), in steps based on ratings from the American Society of Echocardiography. Utilizing both the power spectrum and the bicoherence, which is a measure of frequency coupling, a quantitative measure of restriction severity based on the dominant frequencies present is sought. While the forcing frequency is present throughout all results, normalization and a focus on triadic interactions exposes characteristic frequency bands that can be correlated to restriction severity. Across all Reynolds numbers, the band of frequencies from 100–150 Hz appears significant for moderate to severe restrictions, and a band surrounding 270 Hz increases in prominence with increasing restriction. The bicoherence indicates phase coupling decreases with increasing restriction, providing another quantitative measure of restriction intensity.
A Study on the Vibro-Acoustic Analysis Technology About the Transformer Load-Noise
Authors: Yun Minok , Lee Kanghyuok , Ahn Changhoon , Lee Jinwoo , Kang Jeehwoon , Kim Changwook , Choi Hyunseok 
Published: February 2024

Abstract
Recently, the importance of low-noise design on transformers has been growing. This is due to increasing requirements from customers whose substations are being installed nearby downtowns. Increasingly stringent noise emission limits are therefore being placed on transformers by both regulators and utility operators. However, the absence of adequate modelling tools to predict noise levels of transformers during the design phase is leading to difficulties in consistently meeting the acoustic specifications for the manufacturers. This paper presents a numerical methodology to identify the vibration characteristics and predict the sound pressure levels from the load-noise of large power transformers. The methodology involves development of the vibro-acoustic finite element model of a transformer including the excitations of the forces present in a transformer’s active part. Additionally, the application of the vibro-acoustic modelling methodology with regard to the computer-aided design of transformers has been presented through a sensitivity analysis. The validation of the vibro-acoustic modelling scheme detailed in this paper has been conducted with appropriate experimental measurements. The measurements were conducted on several manufactured transformers. Specifically, it has been shown that experimentally determined modal tests and sound pressure levels are in good agreement with numerical results. Through this process, the analysis technology suggested in this paper was validated.