bluuebunny/crossref_metadata_2025_split huggingface dataset:
Neural Network Modeling of Molecular Beam Epitaxy
Authors: Lee Kyeong K. , Brown Terence , Dagnall Georgianna , Bicknell-Tassius Robert , Brown April , May Gary 
Published: November 2021

Abstract
This paper presents the systematic characterization of the molecular beam epitaxy (MBE) process to quantitatively model the effects of process conditions on film qualities. A five-layer, undoped AlGaAs and InGaAs single quantum well structure grown on a GaAs substrate is designed and fabricated. Six input factors (time and temperature for oxide removal, substrate temperatures for AlGaAs and InGaAs layer growth, beam equivalent pressure of the As source and quantum well interrupt time) are examined by means of a fractional factorial experiment. Defect density, x-ray diffraction, and photoluminescence are characterized by a static response model developed by training back-propagation neural networks. In addition, two novel approaches for characterizing reflection high-energy electron diffraction (RHEED) signals used in the real-time monitoring of MBE are developed. In the first technique, principal component analysis is used to reduce the dimensionality of the RHEED data set, and the reduced RHEED data set is used to train neural nets to model the process responses. A second technique uses neural nets to model RHEED intensity signals as time series, and matches specific RHEED patterns to ambient process conditions. In each case, the neural process models exhibit good agreement with experimental results.
Flow Regimes and Transitions in a Rapid Chemical Vapor Deposition Reactor Using Flow Visualization and Rayleigh Light Scattering
Authors: Mathews Angelo G. , Peterson Jill E. 
Published: November 2021

Abstract
Previous study of carrier gas flow in rapid chemical vapor deposition (RCVD) reactors has been limited mostly to numerical simulations and flow visualizations. In the present work flow regimes were observed and temperatures were measured in a vertical axisymmetric pedestal RCVD reactor using flow visualization and Rayleigh light scattering (RLS) for noninvasive temperature measurement. Flow visualizations revealed that the flow undergoes complex transitions between stable flow regimes as heating occurs. The two dominant stable flow regimes were buoyant stable (BS) and momentum stable (MS). RLS was used to determine the instantaneous carrier gas temperature at discrete points in the test section. The flow regimes and their transition points were easily recognized and agreed with flow visualization data. The flow visualizations and RLS tests showed identifiable trends in transition points between flow regimes and in the types of regimes encountered. These trends were dependent on Grashof number and Reynolds number.
Thermal Analysis of Solidification in a Czochralski-Type Rotating System
Authors: Xu J. , Ferland M. , Zhang H. , Prasad V. 
Published: November 2021

Abstract
A continuum solidification model is used to study transport phenomena in a simulated Czochralski system for various rotation rates of the crystal and crucible. Solidification occurs on a cylindrical seed from the top surrounded by water in the crucible. An enthalpy formulation is adopted for numerical solution of convection-diffusion controlled solidification problems. Predicted solid-liquid interface and temperature distribution are in good agreement with the liquid crystal visualization experiments.
Prediction of Heat Transfer Coefficients Under Sub-Cooled Boiling Conditions
Authors: McAssey Edward V. , Wu Jinfeng , Dougherty Thomas , Yang Bao Wen 
Published: November 2021

Abstract
Data are presented for sub-cooled boiling of water in the range of two to four atmospheres. The results show that the sharp increase in heat transfer coefficient associated with nucleate boiling occurs at wall superheats of 20 °C to 30 °C. Comparisons between experimental and predicted heat transfer coefficients are also presented. The two prediction methods examined are the Chen correlation and the Kandlikar correlation.
Two-Phase Flow Regime Transitions in Microchannel Tubes: The Effect of Hydraulic Diameter
Authors: Coleman John W. , Garimella Srinivas 
Published: November 2021

Abstract
An experimental investigation of two-phase flow mechanisms during condensation of refrigerant R134a in small diameter round and rectangular tubes was conducted. A 4.91 mm round tube, and four round tubes with hydraulic diameters ranging from 1 mm – 4 mm were studied to characterize the influence of tube miniaturization on the flow mechanisms. For each tube under consideration, flow mechanisms were recorded over the entire range of qualities 0 &lt; x &lt; 1, and for five different mass fluxes between 150 kg/m2-s and 750 kg/m2-s. Approximately 50 data points were recorded for each tube to obtain a comprehensive understanding of the effects of geometry, mass flux and quality on the phase-change flow mechanisms. The flow mechanisms were categorized into four different flow regimes: intermittent flow, wavy flow, annular flow, and dispersed flow. In addition, the large amount of data over a wide range of test conditions enabled the delineation of several different flow patterns within each flow regime, which provides a clearer understanding of the different modes of two-phase flow. Transition lines between the respective flow patterns and regimes on these maps were established based on the experimental data. It was found that the intermittent flow regime becomes larger as the tube hydraulic diameter is decreased. Also, the size of the wavy flow regime decreases for the small diameter tubes, and disappears completely for the 1 × 1 mm square tube. These maps and transition lines can be used to predict the flow pattern or regime that will be established for a given mass flux, quality and tube geometry.
Experimental Study of Electrohydrodynamic Pumping Through Conduction Phenomenon
Authors: Jeong S. I. , Seyed-Yagoobi J. , Atten P. 
Published: November 2021

Abstract
In an isothermal liquid, only the Coulomb force which is the force acting on the free charges, can contribute to permanent electrohydrodynamic motion. In the absence of a direct charge injection, pumping can be achieved due to the charges associated with the heterocharge layers of finite thickness in the vicinity of the electrodes which are based on the process of dissociation of a neutral electrolytic species and recombination of the generated ions. This type of pumping is referred to as pure conduction pumping. The conduction pumping mechanism is experimentally investigated here with three different electrode designs. Sufficient pressure heads are generated with very low electric power requirements making the EHD conduction pumping attractive to certain applications such as capillary pumped loops and heat pipes.
A Fully Developed Two-Phase Flow Model in Vertical Channels for Bubbly and Slug Flow Regimes
Authors: Moujaes Samir , Sleight Erika 
Published: November 2021

Abstract
A theoretical model for steady state two-phase vertical upward flow in cylindrical channels is presented. A comparison of the results of this model for a circular channel as well as a reformulated rectangular channel model is partially made with experimental data in the literature. It shows that in general the model predicts the flow characteristics somewhat better in the bubbly regime than the slug flow indicating the need to look further into some of the constitutive relationships used to close the model in this regime.
Evaporation-Combustion Affected by In-Cylinder, Reciprocating Porous Regenerator
Authors: Park Chan-Woo , Kaviany Massoud 
Published: November 2021

Abstract
An existing in-cylinder thermal regeneration concept for the Diesel engines is examined for the roles of the porous regenerator motion and the fuel injection strategies on the fuel evaporation and combustion and on the engine efficiency. While the heated air emanating from the regenerator enhances fuel evaporation resulting in a superadiabatic combustion (thus increasing thermal efficiency), the corresponding increase in the thermal NOx is undesirable.
A multi-gas-zone and a single-step reaction model are used with a Lagrangian droplet tracking model that allows for filtration by the regenerator. A thermal efficiency of 52 percent is predicted, compared to 45 percent of the conventional Diesel engines. The optimal regenerative cooling stroke occurs close to the peak flame temperature, thus increasing the superadiabatic flame temperature and the peak pressure, while decreasing the expansion stroke pressure and the pressure drop through the regenerator. During the regenerative heating stroke, the heated air enhances the droplet evaporation, resulting in a more uniform, premixed combustion and a higher peak pressure, and thus a larger mechanical work.
Thermal Analysis of Lubricating Oil Flow Within a Wet-Disk Clutch
Authors: Jen Tien-Chien , Nemecek Dan 
Published: November 2021

Abstract
A combined theoretical and experimental thermal analysis is conducted on the oil flow between the plates of a wet clutch during an extended slip engagement. An analytical model, using the separation of variables technique, is developed to simulate the temperature rise due to the non-conservative friction and relative motion between the steel plates and friction plates of the clutch. A three-dimensional numerical heat transfer and fluid flow model was developed to calculate the velocity and temperature profiles in the oil groove channel. Typical velocity profiles and temperature contours plots are demonstrated. Friction factor and Nusselt number are presented as functions of axial position. The experiment performed included a wet clutch instrumented with thermocouples and installed in a power-shift transmission where the temperature rise during one clutch engagement was measured. The total energy is then estimated by accounting for system inertia, torque and rotating speeds. Finally, the inlet, outlet temperature rises and the averaged Nusselt number of the oil groove are also presented.
Simulation of Fluid Flow, Combustion, and Heat Transfer in a Coal-Fired Cement Kiln
Authors: Karki Kailash C. , Patankar Suhas V. , Grant Jeff 
Published: November 2021

Abstract
This paper presents the details of a mathematical model for fluid flow, combustion, and heat transfer in cement kilns. The model is based on the finite-volume technique for the solution of the gas-phase equations. The k-ε model is used to represent the turbulence effects. A two-step kinetics scheme is employed to simulate the gas-phase combustion. The Lagrangian formulation is employed for the particle phase, and the coupling between the particle and gas phases is handled by introducing appropriate source terms in the gas-phase equations. The particle reaction model includes coal devolatilization and char oxidation. The radiation heat transfer in the kiln is modeled using the six-flux model. The feed bed is represented as a solid region that is moving in the axial direction with a uniform velocity, which is calculated from the feed rate, feed density, and the fill area. The effect of chemical reactions in the feed bed is modeled by including temperature-dependent heat release/absorption rates in the energy equation.
The model has been applied to a cement kiln in operation. The predicted results agree with the observations and experience for the kiln.
Compressor Blade and Impeller Rotating Disk Vibration Avoidance Parameters
Authors: Kushner Frank 
Published: November 2021

Abstract
Interaction of rotating blades with stationary vanes is a prime consideration for disk design and vibration failure investigations. For a well-designed radial-flow impeller with a cover, the structure is inherently resistant to alternating forces at normal flow conditions. Critical parameters are reviewed with respect to excitation and response. A fundamental parametric equation originally published in 1979 is further explained and verified. Comparisons to open impellers and axial compressor blades that have additional critical design considerations are also presented. Data from strain gages on an impeller gave proof that liquid ingestion was the cause of high excitation, and validated the parametric equation for blade/vane interaction. Particular emphasis is given to avoiding high cycle fatigue failures with stages employing vaned diffusers, which are now much more prevalent. Modal analyses, as well as information from other references that confirms theories are included.
A Numerical Method for the Study of Surge and Flow Instabilities in Gas Compression Systems
Authors: Akyuzlu K. M. , Sakarepalle R. , Albayrak K. 
Published: November 2021

Abstract
A numerical method is developed to study the effect of various geometrical and operational parameters on the stability of flow in gas compression systems. It is hoped that this and similar type of studies will help us to understand the effect of coupling of the flow characteristics of a compressor with that of a pipeline. In this study, the gas compression system is assumed to be comprised of a compressor, a throttling valve, and a long pipe. A nonlinear lumped parameter model is used to represent the compressor. The gas flow inside the pipeline is modeled by discrete elements in which the flow is assumed to be one dimensional, viscous, and compressible. The throttling valve is modeled by a single element where the pressure drop across it is predicted through an empirical relation. The governing set of equations for the comprehensive model are linearized using explicit finite difference techniques and then solved for the unknowns of the problem. The results indicate that the amplitude and frequency of the flow oscillations experienced by the coupled system depend on the length of the pipe. The frictional losses seem to dampen the amplitude of the flow oscillations experienced in the compressor and the pipeline.
Hybrid Damping of Sound Radiated by Plates
Authors: Giovanardi Marco , Degon Brian , Cabell Ran 
Published: November 2021

Abstract
The scope of this work was to design and build a new concept of hybrid active and passive damping system, capable of attenuating sound radiated through structural vibration both in the high and low frequencies by combining the broadband control capabilities of constrained-layer viscoelastics with the narrowband capabilities of active control with piezoceramic actuators and sensors.
The effort was concentrated on modeling the response of a passive damper as well as a piezoelectric actuator in order to optimize the characteristics of both the active and passive damping materials, on implementing a test system and on designing a closed-loop control system to show the advantages of the hybrid approach over purely active or passive approaches.
An extensive research into the available viscoelastic materials was done to find materials with near optimal characteristics. A few of these materials were procured and tested on a simple structure to validate the model and test their performance.
It was demonstrated on a real system that this approach is feasible and has advantages over both the purely active and the purely passive approach. As a test structure, an aluminum panel similar to exterior panels in airplanes was chosen, and a hybrid control system implemented on this structure. An anechoic transmission loss facility, with the panel bolted into a wall and the plate excited by a speaker on one side, was used to determine the reduction in radiated sound achieved by the hybrid damping system.
The compensator for the active part of the damping system was designed as a simple combination of positive position feedback (PPF) filters, and implemented on a digital single-board computer (SBC).
The resulting sound radiation from the panel showed clearly the validity of the concept of hybrid damping, by achieving good reduction in sound both the low and high frequencies within the chosen band of interest, 0-800Hz, and with very little weight added. The total added mass to the aluminum panel was only about 50g, which is very small compared to the amount of mass a passive system with similar performance would weigh for the same structure.
Impact Identification Using Smart Material Sensors
Authors: Peelamedu Saravanan M. , Naganathan Nagi G. 
Published: November 2021

Abstract
The crash performance of an automobile largely depends on the ability to identity impact damage, maintain the passenger safety through deployment of various safety restraint systems, and steer away the vehicle from impact. So, this work is focused on the impact response of an automobile structure so as to find the location, magnitude of impact and asses the severity of damage. The results of the developed generalized forward plate model compared within 2% for FEM and previous other theoretical approaches. The inverse model compared within 7% for location and reconstructed force. Damage severity assessment is also investigated.
Dynamics of a Pipe Conveying Pulsating Flow Near Criticality
Authors: McDonald Robert J. , Sri Namachchivaya N. 
Published: November 2021

Abstract
In this paper, we study the dynamics of a simply supported pipe conveying pulsating flow near the flow velocity where the system first becomes unstable. We study a Galerkin discretization of this system which involves the first two modes of the pipe, near the flow velocity where the two degree of freedom Hamiltonian system possesses a nonsemisimple double zero eigenvalue and a pair of imaginary axis eigenvalues. The damping, as well as me parametric forcing due to the pulsating flow, are considered as perturbations to a conservative system. Using local bifurcation analysis and recently developed global bifurcation methods, we study the transfer of energy from the forced high frequency mode to the unforced low frequency mode. This transfer of energy causes unwanted vibrations in the mode associated with the double zero eigenvalue, due to the 0:1 resonance that this mode has with the high frequency mode.
Variation Analysis for Compliant Assembly
Authors: Hu S. Jack , Long Yufeng , Camelio Jaime 
Published: November 2021

Abstract
Assembly processes for compliant non-rigid parts are widely used in manufacturing automobiles, furniture, and electronic appliances. One of the major issues in the sheet metal assembly process is to control the dimensional variation of assemblies throughout the assembly line. This paper provides an overview of the recent development in variation analysis for compliant assembly. First, the unique characteristics of compliant assemblies are discussed. Then, various approaches to variation modeling for compliant assemblies are presented for single station and multi-station assembly lines. Finally, examples are given to demonstrate the applications of compliant assembly variation models.
Analysis of Sound Signal Generation Due to Flank Wear in Turning
Authors: Lu Ming-Chyuan , Kannatey-Asibu Elijah 
Published: November 2021

Abstract
Ramp-up is a major step in the implementation of manufacturing systems, and is even more critical in reconfigurable manufacturing systems. For a successful reduction in ramp-up time, it is essential to analyze and monitor both the overall manufacturing system and the individual machine tools/processes that comprise the system. Towards this end, we have addressed the issue of monitoring tool wear using audible sound to enable faulty conditions associated with wear to be identified during the process before the part quality gets out of specification. Audible sound generated from the cutting process is analyzed as a source for monitoring tool wear during turning, assuming adhesive wear as the predominant wear mechanism. The analysis incorporates the dynamics of the cutting process. In modeling the interaction on the flank surface, the asperities on the surfaces are represented as a trapezoidal series function with normal distribution. The effect of changing asperity height, size, spacing, and the stiffness of the asperity interaction is investigated and compared with experimental data.
Reverse Engineering Using Rapid Prototyping Technique for Biomedical Application
Authors: Yean Chow Kin , Kai Chua Chee , Hui Du Zhao 
Published: November 2021

Abstract
Rapid Prototyping (RP) technology has found applications in medicine. Model produced using rapid prototyping technique can enhance interpretation, visualization and physical evaluation, and is useful to pre-surgical operation. This paper presents an integrated reverse engineering system for biomedical application. The configuration of this integrated system consists of hardware and software layouts. The components within the hardware layout are completed except the fiber optic link. The components of the software layout are completed. The reverse engineering system using rapid prototyping technique is applied in the case studies of nose prosthesis and ear prosthesis.
The Mathematical Model of Radial Forging of a Hollow Continuously-Cast Ingot
Authors: Babailov Nikolai A. , Bourkine Serguey P. 
Published: November 2021

Abstract
The problem of a detailed research of radial forging is associated with the technological process of direct combination of continuous casting and metal forming. The mathematical model of multi-die radial forging is developed. The strain state of radial forging is investigated. The dependences of main characteristics on technological parameters for radial forging with combined loading (torsion, tension or backing) are received by the variational method.
The thermal analysis of hollow continuously cast ingot during deformation is executed.
The verification of mathematical model adequacy is executed by experimental researches. The design of six-dies forging unit for direct combination with vertical continuous-casting machine is developed.
Effects of Some Modeling Parameters of Finite Element Models of Binder Forming
Authors: Chen Kuo-Kuang , Sa Chung-Yeh 
Published: November 2021

Abstract
This paper studies the effects of some modeling parameters on the accuracy of finite element simulation in sheet metal forming. A simple stepdie, which simulates binder forming, is used. In this two-dimensional case, a flat blank is bent into a sinusoidal shape, which has an exact solution. Four modeling parameters are studied. They are: die close speed, die gap, mass damping and width of blank. One significant finding of this study reveals that in calculations using explicit finite elements, the simulation speed should be selected with care. The dynamic effects may be prevalent if the simulation speed is too fast. Numerical errors may accumulate and renders the results erroneous if it is too slow.
Three-Dimensional Tube Geometry Control for Rotary Draw Tube Bending: Part 2—Statistical Tube Tolerance Analysis and Adaptive Bend Correction
Authors: Lou Huazhou , Stelson Kim A. 
Published: November 2021

Abstract
The control of each individual bend and overall process is presented in part 1 of the paper. In part 2 of the paper, statistical methods are used to analyze and improve 3-D tube bending accuracy. The relationship between bending process error and tube geometry error is obtained with Monte Carlo simulation. For the same tube tolerance requirement, the required process tolerance varies in a large range based on tube geometry. Among the three bending errors: bend angle, bend plane and distance between bends, bend angle error has the largest influence on tube error. For a tube with multiple bends, the overall tube geometry error can be minimized by intentionally modify the nominal values of the bends to be made based on the errors in the existing bends. The required modification of the bending commands is calculated with an adaptive bend correction algorithm.