bluuebunny/crossref_metadata_2025_split huggingface dataset:
Enhanced Wickability of Thin Non-Uniform Sintered Particle Wicks Using Lattice Boltzmann Method
Authors: Borumand Mohammad , Lee Taehun , Hwang Gisuk 
Published: February 2021

Abstract
Thin non-uniform particle size wicks are essential to improve the maximum heat flux of two-phase thermal management systems by improving the wickability. To understand the enhanced wickability, we examine a pore-scale capillary flow within the thin sintered particle wick using a free-energy-based, single-component, two-phase Lattice Boltzmann Method (LBM) with a minimal parasitic current. The developed LBM approach is validated through the rate-of-rise in the two-parallel plates with parallel plates spacing of W = 48 against analytical Bosanquet equation, achieving the RMS error below 10%. The LBM predicts the rate-of-rise through the uniform and non-uniform particle-size wicks between two-parallel plate, including the capillary meniscus front and dynamic capillary filling. At the same plate spacing and porosity, i.e., W = 48 lu and ε = 0.75, the non-uniform particle size wick achieves enhanced wickability by providing the selective flow pathway through pore networks formed in the smaller pores between the small/large particles, which is in qualitative agreement with previous experimental results. The enhancement of the maximum and minimum dimensionless liquid height and the liquid-filled pore ratio of non-uniform particle size wick is found to be up to 11.1, 27.47, and 26.11%, respectively. The simulation results provide insights into the optimal wick structures for high heat flux two-phase thermal management system by enhancing the wickability through the non-uniform particle (or pore) sizes.
Repeatability of a Topology Optimized Tapered Box Beam Additively Manufactured With Electron Beam Melted Ti-6Al-4V
Authors: Bol Eric , Ramulu M. 
Published: February 2021

Abstract
In order for metal additive manufacturing to fully break into the commercial aircraft industry the process has to be stable and repeatable. The product safety of high-quality serial production components is directly related to manufacturing repeatability. In this study a tapered box beam resembling a scaled down commercial aircraft engine pylon forward strut box is designed for additive manufacturing using 3D topology optimization as a guide. The topology optimization algorithm initially sized the structure for maximum stiffness, then the resulting CAD model was redesigned and analyzed for maximum principal stress to reduce the weight. The final design had an asymmetric organic-like truss structure that was manufactured in two halves out of titanium using an Arcam A2X electron beam powder bed fusion machine. A trial build helped to determine the proper support strategy to achieve quality specimens with tight tolerances that would facilitate assembly. To test the manufacturing repeatability a series of three builds was executed to produce six beam specimens for follow-on analysis and strength testing. This paper describes the design, analysis, and manufacturing process for a topology optimized taped box beam that is intended for future ultimate strength testing and analysis.
Analysis on RAMS Information for Metro Vehicles Using Natural Language Processing Algorithm: Evidence From China
Authors: Luo Min , Yu Luman , Yao Yimiao 
Published: February 2021

Abstract
The RAMS information of rail vehicles is an important data for the operation and maintenance of rail transit, and is the key to improving the performance and reliability level of rail vehicle equipment. At present, there are a large number of colloquial, hybridized and subjective data records in the RAMS information of metro trains; especially in the vehicle fault record, this phenomenon is widespread, which brings great difficulties to subsequent data analysis. Therefore, how to convert these irregular fault records into computer-readable fault texts is of great significance. This paper proposes the RAMS information structuring algorithm based on the Jieba word segmentation and Doc2Vec technology. Besides, we compile a professional dictionary of metro vehicles and a standard fault statement library for metro vehicles.
Computational Modelling and Simulation of Pedestrian Subsystem Impactor With Sedan Vehicle and Truck Model
Authors: Mohammed Obaidur Rahman , Suresh D. V. , Lankarani Hamid M. 
Published: February 2021

Abstract
The increase in public transportation in the last decade has resulted in a larger pedestrian population and hence a larger number of pedestrian collisions. In the past, car-pedestrian accident prevention had been a challenge for automotive and transport safety members. Recent reports in car-pedestrian accidents have influenced many improvements to prioritize pedestrian protection for automotive industries. The number of pedestrian fatalities in U.S has raised in last decade proportionally, Car manufacturers, and transport investigation teams are implementing new product designs and adding new development methods to reduce the risk of pedestrian collisions. In this study, adult headform and upper legform is tested with a finite element vehicle model to examine the simulation results and injury behavior during impact. All finite element simulation tests are produced under Euro-NCAP Committee regulations. Finite element models are configured as per the regulation’s and testing criteria. Both upper legform impactor and adult headform finite simulation results are tested with assessing criteria limits. Finite simulation tests are carried on the LS-DYNA – Code platform. This comparative study between sedan and pickup finite vehicle models gives an injury risk prediction of pedestrian safety and assesses design parameters of automotive industries.
Design and Fabrication of Mount Plate for Integration of Multiple Cameras in UAV Using 3D Printing and Traditional Manufacturing Method
Authors: Davis Madelyn , Ball John , Liu Yucheng , Stone Tonya 
Published: February 2021

Abstract
In this project, custom mount plates were designed and fabricated to secure cameras to unmanned aerial vehicles (UAVs) for data collection. An engineering design approach was followed to design the mount plates. Two types of mount plate were fabricated using different methods. One mount plate was cut from G10 fiberglass sheets following a traditional subtractive manufacturing process while the other one was made from 3D printing with polylactic acid (PLA). The two manufacture methods were compared in terms of manufacturing cost, time, and simplicity. Performance of these two plates including compatibility, weight, and strength were also discussed. Results of this project will facilitate researcher’s decision making for choosing the appropriate approach to make such apparatus.
Experimental Study on Flow Boiling of HFE-7100 in Wavy Copper Microchannels
Authors: Cui Peilin , Liu Zhenyu 
Published: February 2021

Abstract
This study experimentally investigated the flow boiling of HFE-7100 in wavy copper microchannel heat sink (20 mm × 10 mm), which was fabricated with the ultrafast laser micromachining approach, consisting of 20 wavy microchannels with wavelength of 2000 μm and wave amplitude of 100 μm with triangular cross section (200 μm × 573 μm). The experiment was conducted with the mass fluxes of 330.07–550.11 kg/(m2·s) and heat flux of 14.5–411.3 kW/m2 at an inlet temperature of 15°C. Four flow patterns including bubbly flow, slug flow, churn flow and annular flow were captured with the visualization technique. Several confined bubbles with irregular shape were observed. In the low heat flux region, the dominant flow regime of heat transfer in the microchannels is the nucleate boiling and the heat transfer coefficient increases with increasing heat flux. With the nucleate boiling suppressed gradually, the evaporation of thin liquid film begins to dominate and the heat transfer coefficient decreases with the increase of heat flux. The heat flux has a significant effect on heat transfer coefficient compared with the mass flux and vapor quality.
Universal Weight Function Method on the Probabilistic Surface Damage Tolerance Assessment of Aeroengine Rotors
Authors: Zhou Huimin , Ding Shuiting , Li Guo 
Published: February 2021

Abstract
The methodology referred as probabilistic surface damage tolerance for aeroengine rotors is used to evaluate the risk of fractures induced by low-cycle failure problems, and fracture mechanical models are usually used to carry out the analysis, in which stress intensity factors (SIFs) need to be calculated. Weight function method (WFM) can help improve the probabilistic surface damage tolerance methodology. The WFM offers remarkable computational efficiency in calculating SIFs for cracks in aeroengine rotors with complex stress gradients that are mainly induced by a local stress concentration or multiple loads, including centrifugal, thermal, and residual stresses. In this case, the universal weight functions (mode I) for surface cracks in three-dimensional finite plates, including flat plates and plates with holes, are presented. The critical step of WFM is to obtain certain coefficients in the universal weight function. Response surface method (RSM) can effectively derive the coefficients determined by multiple geometric parameters, including the length and thickness of a flat plate and the length, thickness, radius of a plate with a hole. Errors between the WFM results and the finite element results are less than 5MPam within the application scope. Furthermore, a surface damage tolerance analysis of the hole features in the aeroengine rotors based on the abovementioned two types of WFM is conducted. The selection of the weight function influences the SIF results, and the probability of failure (POF) calculated by the applied weight function of the plate with a hole is 2.02% higher than that of the flat plate. The relevant difference, which is determined by the fracture threshold crack size, has a negative relationship with the magnitude of stress distributed on the crack surface.
Adaptive Iterative Learning Control of Fluidic Muscle Driven Parallel Manipulators for Force Control With Sliding Mode Technique
Authors: Zhang Xinxin , Li Min , Ding Huafeng 
Published: February 2021

Abstract
In this paper, an adaptive iterative learning control (AILC) method combined with sliding mode technique is proposed to improve the force control performance for repeating tasks of fluidic muscle (FM) driven parallel manipulators. Different from the traditional iterative learning control method, the proposed AILC is to learn the controller time-varying parameters rather than to learn the control signals. Since the AILC is sensitive to non-repetitive disturbances, the sliding mode technique is introduced to enhance the robustness. Since no model information involved in the controller design, the proposed method is a complete data-driven method. Hence, the difficulty of obtaining accurate model is avoided. Simulation studies are performed on a two degrees of freedom FM driven parallel manipulator. Simulation results demonstrate that the proposed method can achieve high force tracking performance and robustness.
Prediction of Blood Flow Distribution in Liver Radioembolization Using Convolutional Neural Networks
Authors: Taebi Amirtahà , Vu Catherine T. , Roncali Emilie 
Published: February 2021

Abstract
We have developed a new dosimetry approach, called CFDose, for liver cancer radioembolization based on computational fluid dynamics (CFD) simulation in the hepatic arterial tree. Although CFDose overcomes some of the limitations of the current dosimetry methods such as the unrealistic assumption of homogeneous distribution of yttrium-90 in the liver, it suffers from the expensive computational cost of CFD simulations. To accelerate CFDose, we introduce a deep learning model to predict the blood flow distribution between the liver segments in a patient with hepatocellular carcinoma. The model was trained with the results of CFD simulations under different outlet boundary conditions. The model consisted of convolutional, average pooling and transposed convolution layers. A regression layer with a mean-squared-error loss function was utilized at the network output to estimate the arterial outlet blood flow. The mean-squared error and prediction accuracy were calculated to measure model performance. Results showed that the average difference between the CFD results and predicted flow data was less than 2.45% for all the samples in the test dataset. The proposed model thus estimated the blood flow distribution with high accuracy significantly faster than a CFD simulation. The network output can be used to estimate the yttrium-90 dose distribution in the liver in future studies.
Effect of Leg Topology on the Energy Conversion Performance of Thermoelectric Generators Systems
Authors: Aljaghtham Mutabe , Celik Emrah 
Published: February 2021

Abstract
Thermoelectric generators (TEGs) convert temperature gradient into electrical power. The shape (or topology) of thermoelectric (TE) leg has a significant impact which can directly affect TEG performance. The conventional uniform, rectangular TE leg configurations were employed widely in TEGs to evaluate the performance of the TE devices. Different leg geometries have been proposed in the past by researchers to enhance thermoelectric efficiency. However, there is no consensus, nor a systematic study exists to find out the ideal leg geometry and maximize the energy conversion efficiency in thermoelectric systems. The current study investigates various configurations of TE legs such as trapezoidal leg, zig-zag leg, butterfly leg, vertical and horizontal cross-shaped leg, X-leg, Y-leg, I-leg based on their individual shape construction. 3-dimensional finite element simulations are conducted to investigate the thermoelectric output power and conversion efficiency of these configurations and compared to (conventional) rectangular TE leg shape geometries. The reliability and accuracy of the used finite element based numerical model are validated with analytical and numerical results. From the study, results indicate that the vertical cross-shaped and butterfly generate more TE output power compared to all other configurations. The (conventional) rectangular TE leg generates around 1.46 Watts which is around 34% and 25% TE power lower than vertical cross-shaped and butterfly configurations, respectively.
Text Writing Using Air Gestures for People With Limited Hand Motor Skills
Authors: Ermidoro Michele , Vitali Andrea , Previdi Fabio , Rizzi Caterina 
Published: February 2021

Abstract
Mobile devices and laptops are the main ICT tools to exchange information among people in the world. All the applications are designed by following a specific interaction style based either touchscreen or mouse and keyboard, which can be performed only with detailed movements of hands and fingers. Traditional interaction becomes difficult for elderly who have diseases limiting the hand motor skills, such as arthritis and brain stroke.
The use of simple air gestures can be adopted as alternative interaction style to interact with smartphones, tablets and laptops. The aim of this research work is the development of an application that allows text writing using air gestures for people with limited hand motor skills. The application embeds several computer vision algorithms and convolutional neural networks software modules to detect and drawn alphanumeric characters and recognizing them using both mobile devices and laptops. The preliminary results obtained show that the approach is robust, and it can easily detect the alphanumeric characters written with the movement of the wrist.
Analysis of Laser Cutting of 1.2mm Thick Austenitic Stainless Steel
Authors: Atayo Asonganyi Ateh , Bashir Mahmood , Rahman Muhammad Mustafizur , Nair Rajeev 
Published: February 2021

Abstract
Stainless steel 304 is one of the most commonly used steel types for corrosion resistance applications, but higher melting point is a limitation in industries from a manufacturing point of view. The non-conventional and subtractive manufacturing technique of laser cutting — a beam directed method, is suitable for these applications. A Gaussian laser beam is directed at the material that melts, burns, vaporizes, or is blown away by a jet of gas, leaving a fine edge with good surface finish. In this study, a numerical study was performed to study the multi-physical fluid processes of laser cutting. Towards this, modeling was performed using 1.2 mm thick austenitic stainless-steel coupons that was cut using a continuous width neodymium-doped yttrium aluminum garnet (CW Nd: YAG) laser. The results showed smoother surface cut, little dross formation, lower temperature rise in heat affected zones, and less finish time at a cutting speed of 8m/min, higher laser power above 1000 W, gas pressure of 11 bars, and focus distance of −1.0 mm. It was observed that an increase in laser power at a faster cutting speed led to an increase in kerf width, reduction in dross formation, lower temperature rises in heat affected zones and a reduced finish time. The simulation results were compared with published experimental data and found to be well within a maximum difference of 15%.
A New Meshless “Fragile Points Method (FPM)” Based on a Galerkin Weak-Form for 2D Flexoelectric Analysis
Authors: Guan Yue , Dong Leiting , Atluri Satya N. 
Published: February 2021

Abstract
A meshless Fragile Points Method (FPM) is presented for analyzing 2D flexoelectric problems. Local, simple, polynomial and discontinuous trial and test functions are generated with the help of a local meshless differential quadrature approximation of the first three derivatives. Interior Penalty Numerical Fluxes are employed to ensure the consistency of the method. Based on a Galerkin weak-form formulation, the present FPM leads to symmetric and sparse matrices, and avoids the difficulties of numerical integration in the previous meshfree methods. Numerical examples including isotropic and anisotropic materials with flexoelectric and piezoelectric effects are provided as validations. The present method is much simpler than the Finite Element Method, or the Element-Free Galerkin (EFG) and Meshless Local Petrov-Galerkin (MLPG) methods, and the numerical integration of the weak form is trivially simple.
Low Wear Debris Compliant Mechanism Cervical Disc Prosthesis
Authors: Brehm Samuel 
Published: February 2021

Abstract
The device outlined in this paper is 3D printable cervical disc prosthesis that uses a compliant mechanism to behave biomechanically like a natural cervical intervertebral disc. The device is DMLS printed out of biocompatible titanium as a single part, and can be manufactured to the custom length, width, height, and lordotic angle desired for the patient. The device has 6 degrees of freedom for flexion, extension, and lateral bending. The device has 0.83 mm of max compression with a compressive stiffness of 473.1 N/mm. The device consists of compliant mechanism with two plates fused on the top and bottom. The mechanism is essentially two perpendicular beams fused at their midpoints. The beams act as rotational as well as compressive springs. This allows the rotational and compressive range of motion. This design is intended to minimize the production of wear debris, which is a problem with prosthetics. It also provides the ability for a disc prosthesis to be easily custom manufactured for the patient.
Investigation of Contact Conditions During Stamping of a Thin Plate
Authors: Shahare Harshal Y. , Rajput Rohan , Tandon Puneet 
Published: February 2021

Abstract
Stamping is one of the most used manufacturing processes, where real-time monitoring is quite difficult due to high speed of the mechanical press, which leads to deterioration of the accuracy of the products In the present work, a method is developed to model elastic waves propagation in solids to measure contact conditions between die and workpiece during stamping. A two-dimensional model is developed that reduces the wave propagation equations to two-dimensional equations. To simulate the wave propagation inside the die-workpiece model, the finite difference time domain (FDTD) method and modified Yee algorithm has been employed. The numerical stability of the wave propagation model is achieved through courant stability condition, i.e., Courant-Friedrichs-Lewy (CFL) number. Two cases, i.e., flat die-workpiece interface and inclined die-workpiece interface, are investigated in the present work. The elastic wave propagation is simulated with a two-dimension (2D) model of the die and workpiece using reflecting boundary conditions for different material properties. The experimental and simulation-based results of reflected and transmitted wave characteristics are compared for different materials in terms of reflected and transmitted wave height ratio and material properties such as acoustic impedance. It is found that the numerical simulation results are in good agreement with the experimental results.
Improved Vibration-Model-Based Analysis for Estimation of Arterial Parameters From Noninvasively Measured Arterial Pulse Signals
Authors: Rahman Md Mahfuzur , Sultana Najmin Ara , Vahala Linda , Reynolds Leryn , Hao Zhili 
Published: February 2021

Abstract
With the goal of achieving consistence in interpretation of an arterial pulse signal between its vibration model and its hemodynamic relations and improving its physiological implications in our previous study, this paper presents an improved vibration-model-based analysis for estimation of arterial parameters: elasticity (E), viscosity (η), and radius (r0) at diastolic blood pressure (DBP) of the arterial wall, from a noninvasively measured arterial pulse signal. The arterial wall is modeled as a unit-mass vibration model, and its spring stiffness (K) and damping coefficient (D) are related to arterial parameters. Key features of a measured pulse signal and its first-order and second-order derivatives are utilized to estimate the values of K and D. These key features are then utilized in hemodynamic relations, where their interpretation is consistent with the vibration model, to estimate the value of r0 from K and D. Consequently, E, η, and pulse wave velocity (PWV) are also estimated from K and D. The improved vibration-model-based analysis was conducted on pulse signals of a few healthy subjects measured under two conditions: at-rest and immediately post-exercise. With E, r0, and PWV at-rest as baseline, their changes immediately post-exercise were found to be consistent with the related findings in the literature. Thus, this improved vibration-model-based analysis is validated and contributes to estimation of arterial parameters with better physiological implications, as compared with its previous counterpart.