bluuebunny/crossref_metadata_2025_split huggingface dataset:
Understanding Surface Form Error: Beyond the GD&T Circularity/Roundness or Cylindricity Callout
Authors: Sahay Chittaranjan , Ghosh Suhash 
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. In manufacturing environments, variations on circular features may occur due to imperfect rotation, erratic cutting action, inadequate lubrication, tool wear, defective machine parts, chatter, misalignment of chuck jaws, etc. The importance of studying roundness form deviations of circular and cylindrical features is to avoid the excessive lateral or radial deviations of the rotating and reciprocating parts during dynamic operations. Hence, whether roundness error can be evaluated accurately and efficiently or not will directly influence the part assembly, product’s function/performance and life. For example, it is inferred that a rotational bearing whose components are not accurately round will tend to be noisy and is likely to fail prematurely. However, the current definition of roundness or circularity per ISO or ASME standards considers the surface’s radial deviations only. If these radial deviations are constrained within two concentric circles with minimum radial separation, this radial separation is defined as the roundness/circularity form error. It is, however, difficult to understand how this radial deviation alone can assure functionality while completely overlooking the circumferential variations/deviations on the surface. This paper is an attempt to investigate the form of circularity deviations along the circumference and whether it plays a significant role in the functionality of round machined parts. The investigation focuses on an accurate spindle and turntable type measuring instrument. On this instrument, the component is rotated on a highly accurate spindle which provides an imaginary circular datum. The workpiece axis is required to be aligned with the axis of the spindle by means of a centering and tilt adjustment leveling table. The polar trace obtained off the surface on a section perpendicular to the spindle axis is analyzed through a Fast Fourier Transformation (FFT). This reveals any periodic circumferential deviations in the corresponding amplitude spectrum of the different harmonics. It is intriguing to note that often only one or two amplitudes in the spectrum are significantly larger than the rest and affect the functionality the most. This paper explores how these multitudes of parameters are to be understood and be incorporated into Geometric Dimensioning and Tolerancing (GD&T) drawings, and further be infused in the undergraduate and graduate engineering curriculum, and be taught as an improved toolkit to the aspiring engineers, design & process engineers and quality control professionals.
Richardson-Zaki Exponents for Particles, Drops and Bubbles
Authors: Loth Eric 
Published: February 2024

Abstract
A broad range of experimental data and resolved-surface simulations were surveyed in terms of their Richardson-Zaki exponents for solid particles (spherical, ellipsoidal and irregular in shape) along with spherical drops and bubbles (both clean and contaminated). For these data sets, the Richardson-Zaki exponent often reasonably represents the volume fraction effect on group particle drag increase for moderate volumetric concentrations, ranging from 3% to 30%. A separable effects assumption was used to determine the influence of Reynolds number on the Richardson-Zaki exponent for spheres (including solid spherical particles as well as clean and contaminated spherical bubbles) based on a hydro-static pressure gradient for a homogeneous mixture of particles in a liquid, and this method compared well with experiments. A similar influence was found for non-spherical fluid particles with moderate deformations. However, highly deformed bubbles can cause a drag reduction at high concentrations, owing to deformations aligned with the flow, so a Richardson-Zaki exponent is no longer valid. In contrast, non-spherical solid particles introduce an additional complexity due to changes in particle orientation as volume fraction increases, especially at low Reynolds numbers, which instead accentuates the drag increase due to volume fraction.
Prediction of Heat Transfer During Condensation of Superheated Vapor Flowing Inside Channels
Authors: Shah Mirza Mohammed 
Published: February 2024

Abstract
Many condensers such as those used in refrigeration and in chemical processing involve condensation of superheated vapor inside channels. Several models have been proposed for the prediction of heat transfer under such conditions but there has not been a comparison of these models with all available data to determine which one to use. Several models have been evaluated in the research reported here. All data that could be found was first compared to four models using the measured single-phase and saturated vapor condensing heat transfer coefficients. This identified the best model. The best model was then compared with data using single-phase and saturated condensing heat transfer coefficients calculated by various correlations. The data analyzed included seven fluids (CO2 and six halocarbon refrigerants), reduced pressure 0.00252 to 0.9492, mass flux 45 to 250 kg/m2s, and superheat up to 42 K. A satisfactory method for the calculation of superheated vapor condensation heat transfer has been identified. The results of this research are presented and recommendations are made for design calculations.
Characteristics of Input Signal of a XY and YX Cut LiNbO3 SAW Using Finite Element Modeling
Authors: Janardhana Ranjith D. , Jackson Nathan 
Published: February 2024

Abstract
Surface Acoustic Wave (SAW) devices were traditionally designed for wireless and communication applications; however, their potential has been explored in various other fields. In recent years SAW devices have shown promising results in acoustofluidics. SAW devices operate at higher frequencies (100’s of MHz) which results in high propagation of mechanical waves on the surface which can be utilized in acoustofluidics applications such as cell separation and atomizer. Integration of SAW on acoustofluidics applications solely depends on the device’s ability to generate an acoustic wave with high magnitude to transfer high levels of energy through the liquid. Various factors such as the shape of wave form and amplitude of the input signal to a SAW can affect the formation of mechanical waves on the surface. Hence, the performance of acoustofluidics applications mainly depends on the selection of input signal to a SAW device. This paper analyzes the characteristics of input signals such as the shape of impulse, signal timing, frequency range, and amplitude by considering piezoelectric substrate XY and YX cut LiNbO3. The results were analyzed in relation to insertion loss which is an important parameter to determine the performance of the SAW device.
Experimental Investigation of Nicker Nut Shell Powder Filler Blended Epoxy-Based Biopolymer Composite
Authors: Pachiappan Arumugam , Velukkudi Santhanam Senthil Kumar 
Published: February 2024

Abstract
The need of biodegradable bio-composite materials has significantly increased in recent years for its uses including packaging, agriculture, medicine, sportswear, insulation, paint, etc. Both the environmental and the economical benefits are achieved from the use of natural fibers and natural fillers. Aeronautical and automotive industries use newly identified lightweight biodegradable composite materials because they are strong, light, and consume less energy. They are recognized for having exceptional properties, such as a high strength to weight ratio, a high stiffness to weight ratio, resistance to corrosion, resistance to water absorption, and high hardness. More and more natural fibers and filler materials are being employed in composite materials to lessen the need for the polymer matrix and enhance their chemical, physical, mechanical and thermal properties and so on. This current analysis is carried out experimentally on the impact of adding natural nicker nut shell powder as filler and epoxy resin as matrix on the fabricated biodegradable composites with different volume percentages (5, 10, 15, 20, 25, 30 and 35% so on). On the created biodegradable composites, the impacts of particle size and filler volume percentages on mechanical parameters like tensile strength, flexural strength, and impact strength have been experimentally assessed. Following the standard of American Society for Testing and materials, the specimens were prepared and tested. The mixture of 25% Nicker nut shell powder and 75% epoxy resin produced the highest tensile strength, which measured as 22.05 N/mm2. The blend of 75% epoxy resin and 25% nicker nut shell powder was discovered to have the maximum flexural strength, measuring 46.9 N/mm2. It has been shown that better interfacial adhesion between the filler and matrix allows for the storage of the largest amount of impact energy, 16.29 KJ/mm2, when the filler and matrix are 25% nicker nut shell powder and 75% matrix, respectively. SEM analysis was conducted to analyze the interfacial bonding between the matrix and filler particles with defects in the composites. SEM images are evidence to attribute better mechanical behavior of bio-composites.
Modeling and Analysis of Terrestrial Locomotion Dynamics of Helical Drive-Propelled Multi-Terrain Vehicles
Authors: Beknalkar Sumedh , Varanwal Aditya , Lynch Ryan , Bryant Matthew , Mazzoleni Andre 
Published: February 2024

Abstract
The diverse and heterogeneous terrains in the Arctic, consisting of snow, melting ice, permafrost, ice-covered lakes, sea ice and open ocean, pose serious challenges to locomotion and autonomous navigation capabilities of rovers deployed in the region for data collection and experimentation. The Multi-terrain Amphibious ARCtic explOrer or MAARCO rover is a proposed screw-propelled vehicle that uses helical drives (similar to Archimedes’ screws) to move seamlessly across the diverse terrains in the Arctic. The motion of a pair of helical drives operating in soft or fluid terrain is dictated by the response of the surrounding substrate to the stresses exerted by the rotating helical drives. If the substrate under the rover does not fail when it is moving in a straight line, the linear displacement of the rover (x) and the number of rotations of the helical drives (n) are related through x = P · n, where P is the pitch length of the helical drives. However, when the substrate fails, the linear displacement of the rover is less than P · n, i.e., x &lt; P · n. Thus, “x = P · n” motion represents the optimal mode of operation for the rover when moving in a straight line. This paper represents the first ever attempt, to the best of author’s knowledge, to derive the conditions necessary for the application of the holonomic constraint x = P · n to the dynamics of a helical drives-based rover.
Response of Graphite to Dynamic Loading and Hypervelocity Jet Impacts
Authors: Huddleston Bradley D. , Mason Thomas A. , Gibson Cody , Angell Colter , Rasmussen Nikki 
Published: February 2024

Abstract
The compressive strengths of three varieties of high purity graphite, PCEA, NBG-18, and NBG-25, as well as the depth of penetration of small-scale charges into these materials was experimentally determined. These grades are similar in density, ranging from 1.80–1.85 g/cc, and nominal apparent porosity, ranging from 18% to 20%, but provide a wide range in maximum grain or particle size from 10s to 1000s of μm. Two very different manufacturing methods are also represented; PCEA is extruded while NBG-18 and NBG-25 are iso-molded. The quasistatic and dynamic strengths of each grade were determined on a load frame and split-Hopkinson pressure bar, respectively. The depth of penetration (DOP) of two small-scale shaped charges, the Teledyne RP-1 and RP-4, was determined against graphite. The global response of the RP-4 impacts was markedly different as the PCEA samples remained intact while all the NBG-25 samples split into 2 or 3 pieces after the jet penetration had completed. However, for all tests, the trusted DOPs fell within 2 cm. Preliminary hydrocode modeling of the penetration events used existing models that were not designed for graphite. The results can be tuned to reasonably reproduce the DOP, but the wound channel geometry is not reproduced well. A model designed for graphite would need to represent graphite’s non-linear and energy dissipation characteristics.
A Preliminary Study of Machining Characteristics of Lens Titanium Alloy (Ti-6Al-4V)
Authors: Polishetty Ashwin , Littlefair Guy 
Published: February 2024

Abstract
Titanium alloys are popular and used in a wide range of design applications in aerospace and biomedical industry due to their advantageous material properties. Titanium is categorised into various grades such as Cp Titanium, Titanium5553 and Titanium64. Grade 5 titanium (Ti6Al-4V) is used in this paper. This paper is a preliminary study of machining characteristics of Laser Engineered Net Shaping (LENS) Titanium alloy (Ti-6Al-4V) using face milling. With the advancement in Additive Manufacturing (AM) technologies, components can be easily and efficiently made into various parts with complex geometries that is not possible using traditional manufacturing methods. All materials processed using AM face the same critical problem that the manufactured part requires a post machining since AM produces relatively poor surface finish. This report presents a study of the machining characteristics of a LENS titanium alloy (Ti-6Al-4V) and its behaviour under a milling operation with a set combinations of machining parameters such as cutting speed, feed rate, depth of cut and wet/dry machining. This report also analysed the surface finish of each sample and its correlation to its wrought counterparts. LENS titanium complied with the notion of increasing cutting speed will result in lower cutting force. The cutting force in dry milling is lower than the force in wet milling. The tool wear in dry milling is higher than the wet milling.
Lightweight Design With Topology Optimization for Additive Manufacturing of Aircraft Components
Authors: Kim Tae-Uk 
Published: February 2024

Abstract
The topology optimization (TO) of a landing gear torque link is performed with the goal for making the part via additive manufacturing (AM). The AM is free from many limitations, which classical subtractive manufacturing intrinsically has, thus it can realize the TO results as near net shape. In this paper, two optimization processes are considered for weight reduction. At first, the conventional TO solutions are obtained for minimizing weight with constraints. And then, the lattice optimization process is applied to the solution in which the intermediate density elements are replaced with lattice structures and the member dimensions are optimized. In addition, as a previous stage for prototyping, the tensile test of additive manufactured coupons is conducted to find basic material properties and the results are adopted into the analysis model. For this, specimens are prepared using a titanium alloy Ti6AL4V with a DMLS (Direct Metal Laser Sintering) system. The optimal results show that a combination of TO with AM can be applied to various lightweight designs of aircraft structures.
Development of a Broadband Energy Harvesting Technique Utilizing Acoustic Metamaterials
Authors: Todd Andrew , Ahmed Hossain , Ahmed Riaz 
Published: February 2024

Abstract
A novel deterministic method to harvest energy within a broadband frequency (0 ∼ 25 kHz) from a mass-in-mass metamaterial is presented. Traditional metamaterials are composed of multiple materials (named as resonators and matrix) with different mechanical properties (e.g., stiffness, density). Typically, the mass-in-mass metamaterial consists of a core material, surrounded by an outer shell. The core material is usually made up of a material with higher density and stiffness, while the outer shell is composed of a less dense and lower stiff material. The subwavelength structures within the shell serve to redirect the acoustic waves, resulting in negative density. In this work, the stiffness of matrix materials is altered systematically to allow diversified property mismatch between the constituent components to introduce local resonance in the unit cell. During the material property manipulations, the properties of the resonator are kept unchanged. By manipulating the subwavelength structures in the outer shell, it is hypothesized to optimize the local resonance with higher density of states. A finite element based commercial solver COMSOL Multiphysics is used to develop the dispersion curve, and an in-house MATLAB code is developed to estimate the density of states at a series of eigen-frequencies. To illustrate the broad-band resonances and the energy harvesting at these frequencies, the dispersion relation, and corresponding DOS are used as a predictive tool. While local resonance leverages wave energy passing through the acoustic metamaterials trapped within the relatively soft matrix as dynamic strain energy, a strategic and deterministic methodology is investigated to obtain a broadband local resonance frequency. A correlation is established between the local resonance and the density of states. Using the proposed geometric configurations, the matrix properties are manipulated and a repeated higher density of states within a broadband frequency range is achieved. By predicting a higher density of states, the possibility of energy harvesting capability within this broadband frequency range is enhanced significantly. Hence, the frequency band is utilized to harvest the trapped energy by embedding a smart material inside the matrix which is capable of electromechanical transduction (e.g., lead zirconate titanate). A series of parametric frequency domain studies are carried out to estimate the power densities for a unit external displacement excitation. This concept has been proved numerically by harvesting energy at a broadband frequency with a power density of ∼ 10μW/in2. The harvested power can directly be utilized to power wireless network sensors, wearable devices, smart buildings, internet of things, and so on.
Numerical Methods for Improving the Optimization Efficiency of Textured Surfaces
Authors: Geng Yu , Chen Li , Liu Heng , Qi Shemiao , Liu Yi , Zhou Rui , Zhang Rongfeng , Fan Bowen , Chen Yinsi , Li Yuan 
Published: February 2024

Abstract
As an emerging tribological technology, surface texturing has been widely studied and applied. More and more scholars have committed to the theoretical optimization of textures. To improve the optimization efficiency of textured surfaces, a multiscale method combining the finite cell method with Fischer-Burmeister-Newton-Schur, named as FCM-FBNS, the Fourier Amplitude Sensitivity Test (FAST) and genetic algorithm (GA) were combined in this paper. The proposed methods can calculate the first-order sensitivity indices of texturing parameters to the tribological characteristics efficiently and fastly. Results show that the texture density is the most crucial geometric parameter; the effects of the cell size are negligible. In addition, the effects of texturing parameters have a close relationship with operating conditions and the same parameters may have different influences on different static characteristics. The parameters with higher sensitivity indices can be defined as the key ones and the GA method was applied to improve the tribological performance of textured surfaces by optimizing these texturing parameters. The results achieved by optimizing only the key parameters are similar to that of optimizing all parameters, but the time can be saving up to 30 percent. The methods not only can reduce the optimization difficulty and time, but also provide a novel perspective to understand the optimization problem by quantifing the influence of input on the output.
Development of a Control System Architecture for a Self-Driving Humanoid, HART
Authors: Sohn Kiwon , Wisdom Jordaine , Sharpe Ethan , Robinson James , Kumar Rahul , Tatoglu Akin 
Published: February 2024

Abstract
The control system architecture development for a full-sized humanoid, HART (Human Assistive RoboT), is presented in this paper. HART has been designed and built by ART (Assistive Robot Team) at University of Hartford since 2017. With its unique design feature, which is kinematic re-scalability, HART can manipulate various control inputs of off-the-shelf vehicles with different sizes and structures in the market. In this study, the control system upgrade that can enable the robot to drive autonomously in trained environments is mainly described. For this, the way-point based navigation capability is built for HART using its trinocular camera system and CNN (Convolutional Neural Network) based terrain classifier. Next, HART’s sensor head, which is also redesigned for advancement of its perception capability, and end-effectors that are upgraded for more efficient manipulation of vehicles’ control inputs are introduced in this paper. Lastly, HART with the upgraded control system is tested and evaluated in human-centered environments.
Experimental Investigation of Vortex Shedding Patterns Behind Tapered Cylinder Pairs
Authors: Barbera Christopher , Hanson Matthew R. , Vaccaro John C. , Rooney David M. 
Published: February 2024

Abstract
An experimental wind tunnel study was undertaken to examine wake flow structures behind solitary finite tapered cylinders and behind pairs of finite tapered cylinders mounted on a flat ground plane perpendicular to a steady uniform upstream flow. Both a straight cylinder and a tapered cylinder were studied. The straight cylinder had an aspect ratio of 24, while the tapered cylinder had an aspect ratio of 32 and a taper ratio of 48. Data were collected at a Reynolds number of 4200 based on base diameter. The cylinder pairs could be oriented at any angle α from 0° to 90° with respect to the oncoming flow. Two center-to-center distances (based on the base diameters) were examined at each incidence angle. It was found that tapered cylinder pairs produced wake interference patterns that were more complex than straight cylinder pairs because the relative spacing of the cylinders increased with spanwise position as the local diameters diminished. Increasing the spacing between two tapered cylinders at α = 0° increased the clarity of spanwise vortex shedding cells. Similarly, increasing the spacing produced two distinct frequencies near the free end of the tapered pair at α = 30°, while for the analogous straight pair, there was only a single shedding frequency recorded over the entire span.