bluuebunny/crossref_metadata_2025_split huggingface dataset:
Tool Path Generation for Free Form Surface Slicing In Additive Manufacturing/Fused Filament Fabrication
Authors: Chaudhry Muhammad Salman , Czekanski Aleksander 
Published: January 2022

Abstract
This study is dedicated to develop 3D printing slicing for more specialised applications. Creation of a physical model is a product of the slicing procedure which results in a stack of 2D planar images. Effects of planar slicing results in stair casing effect and is known to effect the mechanical integrity of the fabricated part. To mitigate such effects we present a preliminary study on free form surface slicing procedure. Surface slicing can compliment current 3D printing to develop more customized solutions in fabrication. Results presented show that the end product yielded is superior than its planar slicing counterpart in two aspects. Firstly, stair casing effect can be avoided and secondly visibly greater degree of visible aesthetics can be achieved. Surface slicing is performed on rectangular patch type geometry. Finally, outcomes of this study has been discussed for further development of surface slicing for more customised applications.
Characterization of Wire-Arc Additively Manufactured (WAAM) of Titanium Alloy (Ti-6Al-4V) for Nanomechanical Properties
Authors: Hossain Md Shahjahan , Pliego Ashley , Lee Jinsun , Taheri Hossein 
Published: January 2022

Abstract
The use of metal additive manufacturing (AM) becomes increasingly popular in many industries. AM can create functional parts with lower cost and lead time than the subtractive manufacturing processes. In AM technology, flaws or defects can be present due to variations in the manufacturing process or quality of raw materials, so AM technologies must still be developed to ensure acceptable and reliable quality of the product. Ensuring the high quality of the AM is crucial for safety in critical applications such as the aerospace industry. Various destructive and nondestructive techniques have been used for testing the AM components and their properties evaluation. The use of various nondestructive testing (NDT) techniques is becoming popular for defect identification and characterization of the parts, and still, more techniques need to be developed for better performance and higher optimization. In this study, wire-arc AM (WAAM) parts as-build and heat-treated components have been characterized for nanomechanical properties and finding possible defects created during the fabrication process. Nanoindentation, surface profilometry, and SEM (Scanning Electron Microscope) were used to characterize various wire-arc additive manufactured Titanium alloy (Ti-6Al-4V) samples. The samples were also being tested for material characteristics at different deposition locations and as-deposited versus heat-treated conditions.
Cell Activity Change After Division Under Wall Shear Stress Field
Authors: Hashimoto Shigehiro , Yonezawa Hiroki , Ono Ryuya 
Published: January 2022

Abstract
Does cell orientation depend on the cell type in the shear stress field? Does that tendency change after the division? In this study, the behavior of each cell after division was tracked by time-lapse microscopic images through 24 hours of culture under a shear stress field. A constant shear stress field was applied to the cells in the Couette flow between the parallel walls: the lower static culture disc and the upper rotating disc. For comparison, four types of cells were used: C2C12 (mouse myoblast), HUVEC (human umbilical vein endothelial cells), 3T3-L1 (mouse adipose progenitor cells), and L929 (mouse fibroblast). The result is as follows. In the wall shear stress field of 1 Pa, HUVEC is oriented parallel to the flow, regardless of the division. In other cell types (C2C12, 3T3-L1, and L929) after division, the deformed cell tends to tilt to the direction parallel to the flow. The experimental results are expected to be applied to engineered tissue technologies.
A Bayesian Machine Learning Framework for Selection of the Strain Gradient Plasticity Multiscale Model
Authors: Tan Jingye , Maupin Kathryn , Shao Shuai , Faghihi Danial 
Published: January 2022

Abstract
A class of sequential multiscale models investigated in this study consists of discrete dislocation dynamics (DDD) simulations and continuum strain gradient plasticity (SGP) models to simulate the size effect in plastic deformation of metallic micropillars. The high-fidelity DDD explicitly simulates the microstructural (dislocation) interactions. These simulations account for the effect of dislocation densities and their spatial distributions on plastic deformation. The continuum SGP captures the size-dependent plasticity in micropillars using two length parameters. The main challenge in predictive DDD-SGP multi-scale modeling is selecting the proper constitutive relations for the SGP model, which is necessitated by the uncertainty in computational prediction due to DDD’s microstructural randomness. This contribution addresses these challenges using a Bayesian learning and model selection framework. A family of SGP models with different fidelities and complexities is constructed using various constitutive relation assumptions. The parameters of the SGP models are then learned from a set of training data furnished by the DDD simulations of micropillars. Bayesian learning allows the assessment of the credibility of plastic deformation prediction by characterizing the microstructural variability and the uncertainty in training data. Additionally, the family of the possible SGP models is subjected to a Bayesian model selection to pick the model that adequately explains the DDD training data. The framework proposed in this study enables learning the physics-based multiscale model from uncertain observational data and determining the optimal computational model for predicting complex physical phenomena, i.e., size effect in plastic deformation of micropillars.
Thermoplastics 3D Printing Using Fused Deposition Modeling on Fabrics
Authors: Blais Maxwell , Tomlinson Scott , Khoda Bashir 
Published: January 2022

Abstract
The creation of large objects by additive manufacturing is something that is desired, but often is unachievable due to the size of the object and capacity of the 3D printer used. To address this issue various techniques on part segmentation have been implemented, including origami, geometric segmentation, and segmentation with manufacturability. However, joining or connecting those segmented or discretized additive manufactured parts can be an issue. In this paper we propose to use fabric as a flexible joint and segment carrier when creating larger objects by additive manufacturing. Specifically, flat simply segmented parts of the desired large object will be additive manufactured on top of a fabric as to adhere the two. Three different fabrics, cotton duck cloth, acrylic-dyed and ripstop, were considered to investigate the interfacial strength with 3D printed PLA. Both treated and untreated fabrics are prepared simultaneously so that parts can be printed on top of them at a predefined spatial location. After the fabrication of segments, adhesion force between the segment and the fabrics are tested with mechanical adhesion tests. We found that untreated cotton duck cloth had an average 78% higher adhesion than other samples. When glue was used to treat fabric before printing a weaker bond between the tri-layer, fabric-glue-PLA sandwich was observed comparative to untreated fabrics. The interfacial strength of 3D printed part printed on fabric can be enhanced by changing print parameters, fiber morphology and fabric properties, and surface modification of fabrics. In this work the fiber morphology and fabric properties show significant impact on the interfacial strength. Adhesion forces desired between fabric and 3D printed part can be tailored per specific large object as needed, per segmentation, using this information. The proposed method can help with the fabrication of multifaceted single objects with localized optimum process parameters which can address the directional anisotropic nature of AM parts and corresponding non-homogeneous performance.
Design of a Fractional-Order Controller for the Large Deep Space Observatory Antenna in Wind Disturbance
Authors: Jiang Jianyu , Wu Bin , Zhou Ting 
Published: January 2022

Abstract
To meet the current and future needs of deep space communication services, some large Deep Space Station antennas had to be built on the existing Deep Space Network sites. The influence of wind disturbance has become a serious problem with the increased size of the antenna. Based on the typical antenna model, a fractional-order controller is designed to improve the pointing accuracy of the antenna in wind disturbance. First, the global stability region of fractional-order proportion integral differential (FOPID) controller for the antenna plant was obtained using the Domain-decomposition (D-decomposition) method, Second, the parameters in the stability region were chosen using a genetic algorithm. Then, the disturbance observer is used to estimate and compensate for the influence of the wind disturbance. Finally, a series of simulations and analyses about this fractional-order control system was conducted, the results show that the fractional-order controller works significantly outperform the traditional proportion integral differential (PID) controller, it achieved a remarkable amelioration in the reduction of overshoot and the capacity of wind disturbance rejection.
Design of Litter Collection Robot for Urban Environment
Authors: Su Jian , Cao Yu , Tang Anqi , Wang Siyuan , Dong Janet 
Published: January 2022

Abstract
Keeping sidewalks clean and tidy is a continuously tough task in modern urban environment, traditional solution of cleaning sidewalk is sanitation workers’ manual sweeping. However, manual work is inefficient, laboring intensive and dirty. Main pollutants on the urban sidewalks are simple litter, they consist of recyclable waste such as paper, cardboard and metal cans, and non-recyclable waste like foam and food residue. Thus, the litter on sidewalks can be cleaned, collected and sorted by robots. This paper will discuss the entire design process of a novel litter collection mobile robot for urban sidewalks, including robot structure, drive system, litter collection mechanisms, and stress analysis and motion simulation. This robot can patrol on the sidewalks in urban environment while collecting and sorting litter along the way.
Currently, for cleaning the road on urban street, motor sweeper vehicles are used. There are no motorized vehicles used to clean the sidewalks. Therefore, this robotic approach will fill the gap, avoiding inefficient and overwhelmed manual work. The robot is designed to adapt various terrains of sidewalks such as brick pavements, cement sidewalks, and asphalt sidewalks. The size of the robot is designed to fit most of sidewalks according to research of sidewalk standards.
The litter collection robot consists of a robust chassis, a driving system, a litter collection system, a sensor system for obstacles avoiding, a navigation system for autonomous control and a vision system for litter sorting. For chassis, based on research on sidewalk size standard, its width is designed less than 80 cm to fit inside the sidewalk and at the same time leave enough space for pedestrians passing robot and conducting normal activities. Its height is designed more than 80cm (including robot arm) to make sure it can be noticed by pedestrians, which will avoid potential safety hazard to pedestrians. The weight of the robot is designed to be light weighted to make the robot easy to carry. Moreover, handles are designed in its structure for the convenience of worker’s carrying. For driving system, a two-wheel driving system is designed to adapt various sidewalks. For litter collection system, a robotic arm with four-finger grippers is designed to pick up litter on the sidewalk, and two standard bins are used to contain recyclable and non-recyclable litter separately. Vision system is designed to detect presence and type of litter, so litter will be placed to different bins accordingly. Navigation system is included to enable the robot patrol along the pre-designed path. By applying abovementioned design, this litter collection robot provides a new autonomous approach for urban sanitation work in collecting and sorting litter on sidewalk.
A Novel Formulation to Predict the Accuracy of Implicit Time Integration Schemes
Authors: Tomar Sanjay Singh , Upadhyay C. S. 
Published: January 2022

Abstract
The article presents a novel approach to re-pose the temporal approximation problem as a recursive scheme in terms of displacement and velocity. The recursion matrix is used to obtain the numerical approximation induced amplitude magnification and frequency dilation. From the amplitude magnification term, expressed as a function of the time-step size, one can easily deduce the stability of the method. Similarly, the frequency dilation term can be used to check the accuracy of the numerical scheme. For each time-approximation scheme, a critical parameter (θ = ωΔt) can be identified to guarantee stability and accuracy of the numerical scheme. The performance of classical time-marching schemes, e.g., Newmark scheme, and other single-step schemes is analyzed. Further, a family of Hermite polynomials-based time-approximation methodology is proposed, that can guarantee any desired higher rate of temporal approximation. A residual norm based a-posteriori error estimator has been proposed to investigate the error in the solution. Sample problems have been solved to demonstrate the effectiveness of the current approach.
Attribute-Wise Value of Information in Engineering Systems: A Simulation-Based Study
Authors: Pandey Vijitashwa , Herrmann Jeffrey W. 
Published: January 2022

Abstract
Many engineering decisions involve uncertainty and require tradeoffs between multiple attributes. Often it is possible to reduce or eliminate uncertainty through data collection, or analysis, or both. Although it generally leads to better outcomes, reducing uncertainty may increase cost. This metadecision of whether to reduce the uncertainty at a given cost is undertaken in the form of Value of Information (VOI) studies. Previous work has considered value of information in singleattribute cases, however, studies of the more challenging multiattribute case are less common. Multiattribute problems can have numerous uncertain variables across alternatives, not all of them easily measurable in money amounts, which makes the VOI analysis more complicated. This paper presents a simulation-based approach for calculating and interpreting the VOI in generic multiattribute decision problems and describes a simulation study that we conducted to explore how the decision problem parameters affect the VOI. The relationship between the VOI and the gain in expected utility (utility-gain) that will result from new information is also discussed. This relationship is not simple and yields some expected as well as counterintuitive results. For example, our results suggest that non-linearity of the utility functions may lead to different VoI calculation for the same utility-gain, depending on the relative position of the alternatives. Finally, this paper discusses the sensitivity of the utility from the decision as a function of decision problem parameters and shows that the magnitude of change in VoI can be predicted from these sensitivities. A vehicle alignment problem in an automotive assembly line is presented to demonstrate the approach. The results show that VoI calculation is a challenging problem that is very much contingent on the parameters of the problem. Our results provide insights into the benefits of different ways to evaluate the value of information in multiattribute problems.
Numerical Simulation of Electrified Liquid Jets Using a Geometrical VoF Method
Authors: Cândido Sílvio , Páscoa José C. 
Published: January 2022

Abstract
The stretch of interfacial flows due to the external application of an electric field has considerable importance in several applications. These range from engineering nanofibres to propulsion, the electrified jets bring us an outstanding technique to perform the emission of microdroplets. The present investigation concerns the resolution of interfacial electrohydrodynamic flows from a numerical standpoint using computational fluid dynamics. The reduced form of the Maxwell equations, for an electrostatic field, and a transport equation for the electric charges are coupled to the standard interFoam solvers on OpenFOAM, which resolves an immiscible two-phase flow. A laminar condition is assumed for the flow thus the laminar incompressible Navier-Stokes’s equations are used to compute the hydrodynamic behavior of the flow and, associated with them, electrically induced body forces are incorporated into the hydrodynamic momentum equation. The Maxwell Stress Tensor (MST) describes electrical surface forces acting on the liquid, making it possible to incorporate that effect on the momentum equation. A new efficient geometric Volume-of-Fluid (VoF) method for general meshes, called isoAdvector, was implemented in OpenFOAM, as a substitute for the Multidimensional Universal Limiter for Explicit Solution (MULES). The open literature on the subject presents quantitative benchmarks that demonstrated a significant improvement in the quality with which we can compute sharper interfaces on immiscible two-phase flows (Gamet, L. et al. 2020). Following this approach, we present here an application of that method to the simulation of the breakup of electrified liquids jets. To validate the implementation of the electric field equations, the order of the accuracy of the spatial and time discretization is herein computed. The validation of the discretization of the electric field equations is accomplished with a planar test case that is considered a benchmark test for this class of flows. The test case showed good accuracy on the resolution of the electric potential and electric field having lesser than 0.1% of difference against the theoretical solution. The code is then applied to a Taylor cone jet. This type of jets is at the base of the Electro-hydrodynamic sprays (EHDS) physics. These latter operate by a potential difference between a conductive liquid, usually on the tip of a needle, and an extractor electrode. The numerical model shows a remarkable accuracy on the prediction of the charged droplet size.
Multi-Objective Model-Based Optimization of Pilot Decision Making for Urban Air Mobility
Authors: Holowsko Nicholas , McComb Christopher 
Published: January 2022

Abstract
The emergence of an Urban Air Mobility (UAM) market utilizing fleets of vertical takeoff and land (VTOL) aircraft has the potential to shorten commutes, alleviate traffic congestion, and transform the way people interact with cities. Both industry and academic effort has been aimed towards predicting and simulating fleet activity for the purpose of informing vehicle design decisions and infrastructure planning activities. However, little effort has been targeted at analyzing aircraft fleet performance and sensitivity to pilot decision making, infrastructure availability, and changing vehicle characteristics. In this work, we utilize an existing proprietary, industry developed, discrete-event simulation tool that calculates air vehicle fleet performance with user specified vehicle and demand parameters. Building on this simulation, we then apply an optimization and sensitivity analysis, identifying the relative importance of different vehicle parameters, network attributes, decision making policies, and demand characteristics as they ultimately relate to objective functions that aim to maximize vehicle utilization and minimize the number of deadhead trips. The result of this analysis will inform critical requirements of the UAM market and highlight the importance of effective vehicle scheduling in a UAM scenario.
Insider Attack Scenario Assessment Framework
Authors: Song Jinwoo , He Xinyu , Moon Young 
Published: January 2022

Abstract
Cyber Manufacturing Systems (CMS) brings improvements to the manufacturing system and offers an information-transparent environment. Although CMS’s enhanced system brings many advantages to its manufacturing process, it is at a higher risk of security breach ironically due to its accessibility and connectivity. Therefore, implementing CMS without adequate security measures will make the system vulnerable to intruders including insiders. To identify insider threats, a risk assessment-based framework has been explored by many researchers in the information security community. however, less work has been done to analyze CMS’s vulnerabilities. Therefore, an Insider Attack Scenario Assessment Framework (IASAF) is proposed in this paper. IASAF is developed to detect the system’s security vulnerabilities and evaluate the insider attack scenarios by using five domains including: actor, preparation, implementation, consequence, and recovery. To validate and demonstrate the effectiveness of the framework, a testbed was used to study a case.
Improvement in Photosensitivity of Dumbbell-Shaped Graphene Nanoribbon Structures by Using Asymmetric Metallization Technique
Authors: Goundar Jowesh Avisheik , Xiangyu Qiao , Suzuki Ken , Miura Hideo 
Published: January 2022

Abstract
The existence of Schottky barrier between the semiconductive graphene nanoribbon (GNR) and the metallic electrodes at its both ends causes a major hurdle in the development of GNR based devices. Here, a dumbbell-shape GNR structure was proposed to solve the problem. This structure consisted of a semiconductive GNR and wide metallic GNR at both ends. The ohmic contact between the wide metallic GNR and metallic electrode was easily achieved. Furthermore, an effective mechanism to enhance electronic band properties of the dumbbell-shape GNR structure by using asymmetric metallization technique is employed. To achieve this, two different metallic electrodes were introduced, Platinum (Pt) and Titanium (Ti), at each end of the GNR channel to break the symmetry in the Schottky barrier at both ends. The asymmetric difference in the Schottky barrier at the electrode/GNR interface at each ends allows for an efficient directional flow of electrons, effectively separating the photo-generated carriers. The individual contributions at each electrode/GNR interface were summed up resulting in a larger absolute photo-induced current. The electron transfer characteristics of the DS-GNR-FET was studied under an irradiation of a light source with a wavelength of 632.8-nm at room temperature. The developed 70-nm DSGNR-FET showed a significantly larger and enhanced photosensitivity of about 1.6 × 107 A/W.m2 as compared to the device fabricated with identical metallic electrodes as the source and drain electrodes.