bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Stochastic Optimization Model for a Joint Pricing and Resource Allocation Problem
Authors: Meng Qiunan , Xu Xun 
Published: January 2021

Abstract
In a competitive and volatile market, the price is needed to make in consideration of the uncertain demands of the customers and the limited capacities of enterprises. This requires the coordination decisions on pricing, delivery and resource allocation to increase profit and guarantee service quality for firms. The joint decision on pricing and resource allocation with demand and processing time uncertainty is becoming an issue for a profit-maximizing firm that produces various products. We propose a two-stage model based on stochastic programming to address this joint problem, aiming to maximize profit of products. We present a scenario-simulation approach to describe the stochastic variables; then the deterministic two-stage mixed integer linear programming model is formulated depending on those scenarios. We develop an algorithm by ant colony algorithm to obtain the near-optimal solutions of the models above. The numerical experiments were conducted to validate the proposed models. The results show that the stochastic approach outperforms the deterministic model in the different problem scales and yield the better values of compared metrics. The outcomes also imply that this joint pricing model can provide managerial inspiration for enterprises in the customization environment.
Model and Simulation of Laser Pulse Absorption in Laser-Induced Plasma Micro-Machining (LIPMM)
Authors: Xie Jiaxi , Ehmann Kornel , Cao Jian 
Published: January 2021

Abstract
Direct laser ablation removes material by directly focusing the laser on the material surface so its performance highly depends on the surface condition. Laser-Induced Plasma Micro-Machining (LIPMM) removes the material by focusing an ultrashort laser pulse in an auxiliary dielectric layer above the material and inducing dielectric breakdown to achieve more accurate energy deposition. The physical process of LIPMM can be divided into two stages: pulse absorption and material removal. This work focuses on modeling the pulse absorption stage by implementing the Finite Difference Time Domain (FDTD) method to provide a unified simulation framework for the ultrashort laser-matter interaction. The simulation model can be divided into three steps: 1) the evolution of the laser field, which is described by FDTD with current and a tightly focused beam with Gaussian entry utilized to approximate the unperturbed laser field near focus; 2) the metal absorption of a ultrashort laser pulse, where a two-temperature model is used and the current is described by the Drude model with mean free time approximated by a three stage model and 3) the water breakdown, which is described by Kennedy’s first order model. Combining the above approaches, the unified framework demonstrates its utility on the example of the water-aluminum boundary in the LIPMM process.
Semiconductor Aspects of the Oxyfuel Cutting Torch Preheat Flame: Part I — Measurements Between Torch and Work
Authors: Martin Christopher R. , Pond Teresa , Tomas Jacob , Schmit Jenna , Miguel Erikson , Untaroiu Alex , Xu Kemu 
Published: January 2021

Abstract
This two-part paper presents precise measurements of the ion currents passing between the torch and work piece of the preheat flame of an oxyfuel cutting torch as a means for replacing contemporary sensing suites. Part I shows that the current-voltage characteristic of the flame exhibits sharp discontinuities common to semi-conductors that we study in various configurations including preheat, pierce, cut, and loss-of-cut. Standoff measurements are made by applying a sinusoidal current signal between the torch and work piece while the resulting voltage amplitude is an indication of flame resistance. Uncertainties are estimated to range from 0.5mm to 1mm (.02in to .04in). Signals for ready-to-pierce and precursors for loss-of-cut are also produced due to the generation of secondary ions from chemical activity at the work piece.
Semiconductor Aspects of the Oxyfuel Cutting Torch Preheat Flame: Part II — The Flame’s Internal Electrical Structure
Authors: Martin Christopher R. , Pond Teresa , Tomas Jacob , Schmit Jenna , Miguel Erikson , Untaroiu Alex , Xu Kemu 
Published: January 2021

Abstract
This two-part paper presents precise measurements of the ion currents passing between the torch and work piece of the preheat flame of an oxyfuel cutting torch as a means for replacing contemporary sensing suites. Part II presents the results of a novel spinning disc Langmuir probe technique to construct spatially resolved measurements of the flame’s ion density distribution. A bias voltage is applied to a .254mm diameter wire protruding from a spinning disc, and as the wire is passed through the flame, the measured currents (on the order 10μA) are collected. The process is repeated with incremental wire depths in the flame to construct the entire planar cross-sectional ion density. Measurements reveal intense ion concentrations in the inner cones that rapidly decay by an order of magnitude in the surrounding flow. The outer cone forms a hollow cylinder of weak ion concentration that declines with distance from the inner cones in a manner consistent with recombination.
Effects of Processing Conditions on Laser Direct Deposited Alumina Ceramics
Authors: Pappas John M. , Dong Xiangyang 
Published: January 2021

Abstract
Additive manufacturing (AM) of high-quality inherently brittle ceramics via laser direct deposition, also known as laser engineered net shaping, is challenging due to high thermal gradients, thermally induced cracks, and porosity, typically accompanied by low powder usage efficiency. It is necessary to have an improved understanding of the effects of processing conditions on the fabricated ceramic parts. In this study, alumina ceramics were fabricated with commercial alumina powders. In particular, this paper studied the effect of laser power and scan speed on single track geometries, thin-wall morphology, grain size, density, and powder efficiency during laser direct deposition of alumina ceramics. A single-track parametric study was first conducted to determine the range of processing parameters that produce quality single-tracks and to aid in matching the z-increment with layer thicknesses. The results showed that increased scan speeds promoted significant grain refinement. Average grain size was reduced by nearly 50% when scan speed was increased from 1000 mm/min to 5000 mm/min. On the other hand, densification reached a maximum of 98% at a scan speed of 1000 mm/min with a slight decrease in density was observed at higher speeds. This indicated a trade-off between porosity and grain size when altering the laser scan speed. Significant advantages of using CO2 lasers for AM of ceramics was also demonstrated with powder usage efficiencies reaching nearly 90% under optimized processing conditions.
Research on Chip Formation Mechanism of Laser-Assisted Machining of Fused Silica Based on Variable Laser Angle
Authors: Pan Pengfei , Song Huawei , Xiao Junfeng , Yang Zuohui , Ren Guoqi , Chen Xiao , Xu Jianfeng 
Published: January 2021

Abstract
Laser-assisted machining (LAM) is a promising technology for improving the machinability of hard-to-cut materials. In this study, based on the finite element method (FEM), a cutting model of thermally coupled non-uniform temperature field is established. The chip formation mechanism of fused silica during the laser-assisted machining process is explored from the aspects of laser power and laser incident angle. The results show that as the laser incident angle increases, the continuity of the chip increases gradually. An annular tool holder that can adjust the angle between the laser beam and the tool was designed. And the similar chip morphology obtained by variable-angle cutting experiments verified the effectiveness of the cutting model. Moreover, fracture chips and continuous banded chips are found in both simulation and experiment, which implies that the cutting mechanism works under a hybrid mode of brittle fracture and plastic deformation in the LAM process.
Experimental Investigation of Electrochemical Micro Turning of Ti6Al4V With NaOH Solution
Authors: Das Arnab , Kumar Deepak , Kumar Mohan , Bajpai Vivek 
Published: January 2021

Abstract
Ti6Al4V is a highly favorable material in biomedical, aerospace and many other industries. However, rapid tool wear during machining has made Ti6Al4V into a difficult-to-machine material. Electrochemical machining may be a solution to that challenge. Moreover, high chemical affinity and formation of oxide layer over the surface have limited the application electrochemical machining for Ti6Al4V. In this paper, an experimental approach of electrochemical micro turning of Ti6Al4V has been described. The electrolyte was 10% aqueous solution of NaOH and the tool was SS 310. For each and every experiment workpiece rotational speed and machining time were kept constant. Constant DC voltage was applied and the inter-electrode gap between tool and workpiece was kept constant for each experiment. Experiments were performed using two different levels of applied voltage, axial feed rate and inter-electrode gap. Their effects over MRR and surface roughness have been determined. Additionally, the optimum working condition was determined in order to maximize MRR and minimize surface roughness. For each experiment, acceptable material removal and good surface finish have been achieved. The maximum surface roughness (Ra) was found 1.128 μm in experiment 1. The utilization of NaOH solution has resulted in controlled electrolyzing current, controlled material removal and therefore, good surface finish.
IoT Based Energy Efficiency Monitoring in Stamping Workshop
Authors: Gan L. , Xiong W. , Li L. , Zhu L. , Huang H. 
Published: January 2021

Abstract
Stamping is employed in a wide range of applications including household appliances, automobiles, vessel, and aerospace. Due to the discrete flow energy-intensive processes and dynamic energy changes in stamping production, it has great potential for energy savings. There still lacks an effective method to monitor and analyze the energy efficiency in stamping workshop. To this end, this paper proposes an energy efficiency monitoring and analysis system based on Internet of Things (IoT). The characteristics in stamping workshop are first analyzed, the energy consumption is decomposed, and the makespan is quantified. Besides, energy efficiency indicators of energy efficiency in the press machine, specific energy consumption in the part, and energy efficiency in the workshop are analyzed and defined. Then the detailed information about the energy efficiency monitoring and analysis system as data acquisition, data transmission, data storage, data analysis, and display based on IoT is presented. Finally, a forklift stamping workshop was investigated to validate the effectiveness of the proposed method. The interface and the results of the data analysis showed that the proposed system can monitor the energy efficiency in the stamping workshop comprehensively. Furthermore, potential opportunities for energy consumption reduction and efficient production can be identified.
Numerical Modeling of Powder Gas Interaction for Laser Powder Bed Fusion Process
Authors: Li Xuxiao , Tan Wenda 
Published: January 2021

Abstract
The powder motion induced by the gas flow has been identified as one of the critical phenomena in laser powder bed fusion processes that significantly affects the build quality. However, the gas dynamics and its induced driving forces for the powder motions have not been well quantified. A numerical model is developed to investigate such powder-gas interactions. With a combination of computational fluid dynamics and particle tracking techniques, the model is capable of simulating the transient gas flow field surrounding the powder and the forces exerted on powder surfaces. The interaction between metal powders and a free jet is investigated with the current model. In the simulation results, the entrainment and the ejection motions of powders with respect to the free jet can be predicted. It is found that the driving forces of these motions are majorly contributed by the pressure differences in the gas flow surrounding the powder, and the powders can also interact with the jet to significantly alter the flow field. Quantities which are difficult to measure by experiments are quantified by the simulations, such as the velocity and pressure field in the gas, as well as the subjected forces and torques of powders. Such quantitative information provides insights to the mechanisms of the powder-gas interaction in laser powder bed fusion processes.
Simulating the AM Production Facility: A Configurable Software Tool for Strategic Facility-Level Planning
Authors: Shakirov Eldar , Gee Kaitlyn , Quinlan Haden , Hart A. John , Fortin Clement , Uzhinsky Ighor 
Published: January 2021

Abstract
Additive Manufacturing (AM) — one of several core digital technologies in “Industry 4.0” — is increasingly being deployed in industrial-scale contexts. The successful serial production of end-use polymer and metal components has demonstrated the possibility of AM as a primary production process in several applications. However, one of the principal challenges to greater adoption is a lack of organizational mastery over AM’s implementation in production contexts, and, more specifically, the absence of clear decision-making tools to facilitate exploration of implementation scenarios. To this end, this work proposes the use of a discrete-event simulation-based software modelling tool to investigate the influences of different facility-level planning decisions on techno-economic characteristics of serial production by AM. By changing key parameters, this tool enables users to observe variation in part cost, identify the contributions of individual system elements to part cost, and assess overall system throughput. The tool enables users to identify locally optimal solutions and make corresponding planning decisions, and to explore limiting cases of cost and lead time. In conclusion, we identify the limitations in the current modeling approach, and propose additional directions for future study.
Finite Element Formulation for Modeling Laser Processing
Authors: Hu Ruixiong , Bloomfield Max O. , Shephard Mark S. , Maniatty Antoinette M. , Sikka Kamal 
Published: January 2021

Abstract
A three-dimensional (3D) transient finite element formulation for modeling laser processing is presented, with the capability to simulate both additive manufacturing and laser ablation physics. State variables are introduced to model the phase change phenomenon and to track the phase and phase history throughout the simulation. Temperature dependent material properties are used to capture the nonlinearity of a typical phase change problem. A level set approach is introduced in the subtractive manufacturing simulation, in order to effectively track the rapidly receding surface due to material vaporization and to update the incoming energy distribution for the pulsed laser source on the new geometry. The 3D finite element simulation is implemented in a parallel multi-physics finite element solver, enabling high-performance computation. Simulation results, for both additive and subtractive manufacturing, are acquired, where the size of melt pool and ablation region (width and depth) are predicted quantitatively.
Enhancing Conductivity in 3D Bulk-Embedded Electronics
Authors: Jahangir Md. Naim , Cleeman Jeremy , Malhotra Rajiv 
Published: January 2021

Abstract
Integrating nanoparticle (NP)-based electrically conductive elements inside additive manufactured parts has a high potential for next-generation smart structures. We investigate, a novel technique in which mixed silver nanowires (NW) and nanospheres (NS) are printed as interconnects and sintered using out-of-chamber Intense Pulsed Light (IPL) sintering inside 3D printed thermally sensitive Acrylonitrile Butadiene Styrene (ABS) and Polylactide (PLA) polymer structures. The inclusion of NWs with the typically used NSs is found to realize dual advantages of no thermal damage of the polymers and a that is much lesser resistivity than the state-of-the-art (13.1 μΩ-cm) only 8X higher than bulk silver. Resistivity decreases with a greater percentage of NW content. On the contrary, the NS-only sample didn’t show any conductivity even after IPL sintering because the wavy feature of 3D printed surface didn’t allow NSs to bond. Even though a greater reduction of resistivity is achieved due to IPL, sintering temperature was below 97°C and maximum sintering time reported is 0.75 seconds which cumulatively resulted in damage-free substrates. When dynamic resistivity is analyzed during polymer overprinting on interconnects, four different resistance trends are seen and explained here. Surprisingly, overprinting on the post-IPL interconnect to fully embed the interconnect inside the structure causes a further resistivity reduction to 11.8 μΩ-cm as well.
Analytical Investigation of Varying Deformation Paths Using Microtube Inflation and Axial Tension
Authors: Mamros Elizabeth M. , Kinsey Brad L. , Korkolis Yannis P. 
Published: January 2021

Abstract
Manufacturers invested in a diverse array of industries, ranging from automotive to biomedical, are seeking methods to improve material processing in an effort to decrease costs and increase efficiency. Many parts produced by these suppliers require forming operations during their fabrication. Forming processes are innately complex and involve a multitude of parameters affecting the final part in several ways. Examples of these parameters include temperature, strain rate, deformation path, and friction. These parameters influence the final part geometry, strength, surface finish, etc. Previous studies have shown that varying the deformation path during forming can lead to increased formability. However, a fundamental understanding of how to control these paths to optimize the process has yet to be determined. Adding to the complexity, as the forming process is scaled down for micromanufacturing, additional parameters, such as grain size and microstructure transformations, must be considered.
In this paper, an analytical model is proposed to calculate strain-paths with one or two loading segments and their associated stress-paths. The model is created for investigations of stainless steel 316L using a microtube inflation/tension testing machine. This machine allows for the implementation of two-segment strain-paths through biaxial loading consisting of applied force and internal pressure. The model can be adjusted, based on the desired forming process or available equipment, to output the appropriate parameters for implementation, such as force, displacement, and pressure.
Reducing Variability in Chemical Vapor Deposition of Carbon Nanotubes Based on Gas Purification and Sample Support Redesign
Authors: Tomaraei Golnaz , Abdulhafez Moataz , Lee Jaegeun , Bedewy Mostafa 
Published: January 2021

Abstract
The synthesis of vertically aligned carbon nanotubes (CNTs), also referred to as CNT forest, by chemical vapor deposition (CVD) is an intricate process that is sensitive to multiple factors other than control of temperature, pressure, and gas flows. In particular, growth is highly sensitive to factors like ambient humidity, as well as small quantities of oxygen-containing species and carbon deposits inside the reactor. These typically uncontrolled factors significantly affect growth reproducibility and hinders the fundamental study of process-structure-property relationship for these emerging materials. Accordingly, universally applicable design modifications and process steps toward improve growth consistency are sought after. In this study, we introduce two new modifications to our custom-designed multizone rapid thermal CVD reactor and demonstrate their impact on growth: (1) reconfiguring the inlet gas plumbing to add a gas purifier to the helium (He) line, and (2) designing a new support wafer for consistent loading of substrates. We use statistical analysis to test the effectiveness of these modifications in improving growth and reducing variability of both CNT forest height and density. Analysis of our experimental results and hypothesis testing show that combining the implementation of He purifier with the redesigned support wafer increases forest height and reduces the variability in height (17-folds), both at statistically significant and practically significant levels.
Analysis of a Multi-Material Bone Plate and its Effect on Interfragmentary Strain for Bone Remodeling Processes
Authors: Hossain Anamul , Tipper Joanne L. , Wei Dongbin 
Published: January 2021

Abstract
The success of bone repair using an internal fracture fixation technique is critically dependent on the stability and biological process between the fragmented bones. However, the currently used bone plates mainly focus on stability rather than biology of healing, which subsequently (a) results in significant stress-shielding effects and (b) prevents stress from transferring from the bone plate to the bone during the healing process. This study proposes a novel design of a bone plate for the fixation of long fractured bones, which can mitigate these disadvantages to strike a balance between stability and biology. The new multi-material design adopts stainless steel (SS316L) and magnesium alloy (AZ31B) of three thicknesses such as SS316L (1mm)-AZ31B (2mm), SS316L (1.5mm)-AZ31B (1.5mm), and SS316L (2mm)-AZ31B (1mm). The mechanical properties (bending stiffness and moment) of the bone plates were evaluated according to the ASTM: F382-17 standard. Static corrosion tests were conducted in Hank’s Balanced Salt Solution (HBSS) at 37.5 °C. Compared with those of the original (non-corroded) bone plates, the maximum load-carrying capacities of the corroded bone plates decreased from 670 N to 495 N, 891 N to 518 N, and 928 N to 709 N in the case of SS316L (1mm)-AZ31B (2mm), SS316L (1.5mm)-AZ31B (1.5mm), and SS316L (2mm)-AZ31B(1mm), respectively. Digital image correlation was utilized to evaluate the inter-fragmentary strain (IFS) in the physical model of fractured bone plates. The IFS increased from 0.526 to 0.815, 0.484 to 0.784, and 0.455 to 0.533 in the case of SS316L (1mm)-AZ31B (2mm), SS316L (1.5mm)-AZ31B (1.5mm), and SS316L (2mm)-AZ31B (1mm), respectively, when a load of 200 N was applied. An optimized design of the bone plate of SS316L and AZ31B for granulation tissue formation based on Perren’s theory and IFS was successfully proposed.