bluuebunny/crossref_metadata_2025_split huggingface dataset:
Numerical Simulation of a Dielectric Material Exposed to Short Pulsed Laser Radiation
Authors: Whalen Richard A. , Kowalski Gregory J. 
Published: November 2021

Abstract
A numerical simulation code is developed to study laser beam propagation and the significance of self-focussing or defocusing effects on a manufacturing process. The solution method includes the thermally stimulated nonlinear optical effects caused by the temperature and intensity dependent index of refraction. The results demonstrate that radial temperature gradient magnitudes of 0.06 to 0.6°C produce significant changes in the focal volume of the beam. The magnitudes of the temperature changes are directly related to differences in the absorption coefficient. The thermal transport of the absorbed radiation is modeled using Fourier heat conduction for long time scales and Hyperbolic heat conduction for short time scales. The focal volume of the beam is significantly altered by the differences between these thermal transport mechanisms. These results were determined using a simulation of a Z-scan measurement technique.
Heat Transfer and Phase Transformations in Laser Annealing of Thin a-Si Films
Authors: Moon Seung-Jae , Lee Minghong , Grigoropoulos Costas P. 
Published: November 2021

Abstract
The liquid-solid interface motion and the temperature history of thin Si films during excimer laser annealing are observed by in situ experiments combining time-resolved (∼lns) thermal emission measurements, optical reflectance and transmittance at near-IR wavelengths and electrical conductance measurements. The spontaneous nucleation temperature in the supercooled liquid melt is studied from the thermal emission measurement A new double laser recrystallization technique using a temporally modulated CW Ar+ laser in conjunction with a superposed nanosecond laser pulse produces lateral grain growth at the irradiated spot. The laser melting process is numerically simulated. High-resolution laser flash photography enabled in-situ direct visualization of the resolidification process. The images reveal lateral solidification velocity of about 10 m/s.
Use of Sensors and Actuators to Address Flow Disturbances During the Resin Transfer Molding Process
Authors: Lawrence Jeffrey M. , Advani Suresh G. 
Published: November 2021

Abstract
In Resin Transfer Molding a fiber preform is placed in a mold, the mold is closed and a thermoset polymeric resin is injected through gates into the mold to saturate the preform completely. The resin flow rate is controlled by actuators, which are usually injection machines. When one places the preform into the mold, the gap between the preform and the mold walls can create racetracking channels and provide the resin flow paths that can severely influence the flow patterns and drastically change the flow history. As this gap is unavoidable and not reproducible, one could have different strengths of this disturbance from one part to the next, some of which will cause incomplete saturation of the fibers by the resin. Hence, an active control of the filling stage is necessary which can detect and characterize the race tracking and provide the control action to re-direct the flow with the aim to saturate the preform without resin starved regions (macro voids or dry spots). A methodology is proposed that intelligently places sensors in the mold to detect the resin arrival times at these locations. This information is used to determine and quantify the strength of the disturbance and used as an input parameter for the actuators to redirect the flow. This paper demonstrates this methodology on a simple mold configuration, and outlines how this technique can be generalized to any mold geometry or disturbance set in an automated RTM environment. Numerical simulations are used to establish the control methodologies, and all of the efforts are confirmed in a laboratory setting. The proposed methodology should prove useful in increasing the yield of Resin Transfer Molded parts.
Steady and Transient Flow of a Non-Newtonian Chemically Reactive Fluid in a Twin-Screw Extruder
Authors: Zhu W. , Jaluria Y. 
Published: November 2021

Abstract
The flow of chemically reactive non-Newtonian materials, such as bio-polymers and aciylates, in a fully intermeshing, co-rotating twin-screw extruder is numerically investigated. A detailed study of the system transient behavior is carried out. The main transient aspects, including response time, variation of system variables, and instability of operation, are studied for both single- and twin-screw extruders. The effect of a time-dependent variation in the boundary conditions is studied. The coupling due to conduction heat transfer in the screw barrel is found to be very important and is taken into account for single-screw extruders. In the absence of this conjugate coupling, the response time is much shorter. Several other interesting trends are obtained with respect to the dependence of the transient response on the fluid, materials, and operating conditions. Steady state results are obtained at large time. The calculated velocity distributions in the screw channel are compared with experimental results in the literature for steady state flow and good agreement has been obtained. The numerical results show that not all desired operating conditions are feasible. The calculated results for transient transport agree with the few experimental observations available on this system. These results will be useful in the design, control and optimization of polymer extrusion processes.
Experimental and Numerical Investigation of Polymer Preform Heating
Authors: Reeve Hayden M. , Mescher Ann M. , Emery Ashley F. 
Published: November 2021

Abstract
The transient heating of a polymer preform within a cylindrical furnace is the initial step in the manufacture of polymer optical fiber. A numerical model was used to simulate the radiative and convective heat transfer within the furnace enclosure during this initial heating. Results illustrate a strong dependence of the preform’s heating rate on the radiative properties of the preform. Due to the prominence of radiative heat transfer at steady-state, the resulting axial temperature profile within the preform is strongly coupled to the corresponding axial temperature profile of the furnace wall. Numerical predictions were compared with experimental results for several preform surface emissivities, preform diameters, and thermal boundary conditions. The results compare well for preforms with well-characterized surface finishes (such as black paint and aluminum), with discrepancies between experimental and numerical results typically less than 1.3°C. Experiments indicate that the heating characteristics of poly(methyl methacrylate) preforms can be adequately simulated by assuming that the preform exhibits nearly blackbody behavior (ε = 0.96) when exposed to the low furnace temperatures (85°C) used in this study. Finally, the experiments revealed the tendency for unstable natural convection within tall furnace cavities, with experimental readings indicating oscillatory air temperatures as the system approached steady-state.
Thermal Spray: A Case History for the Integration of Materials Science and Thermo-Fluid Dynamics
Authors: Berndt Christopher C. 
Published: November 2021

Abstract
The thermal spray process involves the injection of particulates into a high flux environment so that momentum and heat transfer can take place. The particles are then accelerated within the gaseous effluent and within several milliseconds impact and splash against a suitably prepared substrate. In this fashion a coating rapidly grows over a time period that may range from minutes to hours.
The materials engineering concept comes into play when it is appreciated that the temperature, velocity, and chemical nature of the spray effluent controls the dispersion, impact phenomenon, and, therefore, the precise nature of the microstructure which is being formed in situ and in real time. Unsurprisingly, this is a somewhat random and chaotic process that is seeking practical and theoretical solutions so that some manner of engineering control can be employed.
This paper explores the scientific relationship between materials engineers and mechanical engineers so that a functional product can evolve. This relationship includes (i) the use of diagnostic equipment to monitor the spray process, (ii) the dynamic impact behavior of particulates, (iii) modeling of thermal fluxes and the resultant mechanical stress state, and (iv) the way in which the microstructure evolves. The eventual aim of this vast body of work is to enable real time feedback loops for the thermal spray process so that predictable and engineered structures can be manufactured.
Heat Transfer in Chemical Vapor Deposited Optical Fiber Coatings
Authors: Iwanik Patricia O. , Chiu Wilson K. S. 
Published: November 2021

Abstract
A fundamental understanding of how reactor parameters influence the fiber surface temperature is essential to manufacturing high quality optical fiber coatings by chemical vapor deposition (CVD). In an attempt to better understand this process, a finite volume model has been developed to study the gas flow and heat transfer of an optical fiber as it travels through a CVD reactor. This study showed that draw speed significantly affects fiber temperature inside the reactor, with temperature changes up to 45% observed under the conditions studied. Multiple heat transfer modes contribute to this phenomena, with convection heat transfer dominating the process.
Prediction of Thermal Contact Conductance by Surface Deformation Analysis
Authors: Singhal Vishal , Garimella Suresh V. 
Published: November 2021

Abstract
An improved method has been developed for the prediction of thermal contact conductance between two nominally flat metallic rough surfaces by analysis of the deformation of individual asperities in contact. The deformation of the asperities in contact has been taken into account by considering three different modes of deformation — elastic, elastic-plastic and plastic. The model uses an iterative procedure to determine the real area of contact between the deformed surfaces for a given load, nominal area of contact, surface profiles and material properties of the surfaces in contact. The contact conductance is then determined as a function of the ratio of the real area of contact to the apparent area of contact The predicted variation of contact conductance with load obtained from the model is compared to simplified analytical predictions in the literature as well as to experiments conducted as part of this work.
Small Heat Source Effects in Sub-Micron Heat Conduction
Authors: Narumanchi Sreekant V. J. , Murthy Jayathi Y. , Amon Cristina H. 
Published: November 2021

Abstract
Decreasing dimensions of integrated circuit devices is leading to increased importance of microscale heat transfer effects and the failure of Fourier’s law in predicting sub-micron heat conduction. In compact transistors, large electric fields near the drain side create hot spots whose dimensions are smaller than the phonon mean free path in the medium. Under these conditions, the phonon Boltzmann equation (BTE) needs to be solved in order to resolve the non-local thermal conduction phenomena. In this paper, the problem of an unsteady heat source of size comparable to or smaller than the phonon mean free path is considered. The unsteady 2-D phonon Boltzmann transport equation in the relaxation time approximation is solved using a finite volume method. The interaction of the heat-up time constant with the phonon residence time in the hotspot and also its interaction with the time scales associated with scattering processes are studied. The results are useful in assessing the peak temperatures during unsteady operation in microelectronic devices.
Ballistic-Diffusive Equations for Transient Heat Conduction From Nano- to Macroscales
Authors: Chen Gang 
Published: November 2021

Abstract
In this paper, we present the derivation of a new type of heat conduction equations, named as the ballistic-diffusive equations, that are suitable for describing transient heat conduction from nano- to macroscale. The equations are derived from the Boltzmann equation under the relaxation time approximation. The distribution function is divided into two parts. One represents the ballistic transport originating from the boundaries and the other is the transport of the scattered and excited carriers. The latter is further approximated as a diffusive process. The obtained ballistic-diffusive equations are applied to the problem of transient heat conduction across a thin film and the results are compared to the solutions for the same problem based on the Boltzmann equation, the Fourier law, and the Cattaneo equation. The comparison suggests that the ballistic-diffusive equations can be a useful tool in dealing with transient heat conduction problems from nano- to macroscales. Boundary conditions for the derived equations are also discussed. Special emphasis is placed on the consistency of temperature used in the boundary conditions and in the equations.
The Effect of Sink Temperature on a Capillary Pumped Loop Employing a Flat Evaporator and Shell and Tube Condenser
Authors: Cerza M. , Herron R. C. , Harper M. J. 
Published: November 2021

Abstract
An experimental facility for conducting research on capillary pumped loop (CPL) systems was developed. In order to simulate shipboard cooling water encountered at various locations of the ocean, the heat sink temperature of the facility could be varied. A flat plate, CPL evaporator was designed and tested under various heat sink temperatures. The sink temperature ranged from 274.3 to 305.2 K and the heat input varied from 250 to 800 W which corresponds to heat fluxes up to 1.8 W/cm2. The CPL flat plate evaporator performed very well under this range of heat input and sink temperatures. The main result obtained showed that a large degree of subcooling developed between the evaporator vapor outlet line and liquid return line. This condensate depression increased with increasing heat input.
Combination of Holographic Interferometry and Digital Speckle Tomography for Analysis of Three-Dimensional Density Distributions
Authors: Ko H. S. , Okamoto K. , Madarame H. 
Published: November 2021

Abstract
A digital speckle tomography has been combined with a holographic interferometry to improve the accuracy of reconstruction of density distributions. For the combined system, several beam splitters have been used to separate the laser beams from a continuous wave laser for the digital speckle tomography and the holographic interferometry so that measurements can be performed simultaneously by both of the experiments. The density distributions have been reconstructed by the tomography methods for both of the experiments. While the projection of the digital speckle tomography expresses the integration of the density gradients, those of the holographic interferometry can be obtained from the integration of the density itself. Thus, the steep region of the density distribution has been reconstructed by the use of the digital speckle tomography more accurately while the holographic interferometry has been used to calculate the density distributions for other regions from the simultaneous measurements of the combined system. Initially, the downward CO2 flow from one-nozzle and two-nozzle test sections have been investigated to confirm the accuracy. Then, the downward flow of CO2 from a circular small opening with a vertical partition (CO2-air exchange flow) has been analyzed for the transient three-dimensional density fields by the proposed combined system in this study.
Heat Generation in Bone Cutting-Implications for Thermal Necrosis
Authors: Millon Debra Chenet , Hitt Darren L. , LaPointe Stephan J. 
Published: November 2021

Abstract
A bunion is a common foot disorder caused by an abnormal outward projection of the joint and inward turning of the toe. Surgery to correct the malformation involves cutting the first metatarsal head, repositioning and setting it; the bone is then left to heal itself over time. A potentially serious by-product of the bone cutting is the frictional heat generated. While the heat susceptibility of individual bone cells varies throughout bone and is difficult to quantify, studies have shown that when injured, bone may not always heal as bone but rather as a fibrous tissue of varying degrees of differentiation. Prolonged heat exposure at or above critical temperatures may also lead to fat and bone cell resorption, a subsequent fat cell degeneration of the tissue, local swelling of cells as well as denaturation of the enzymatic and membrane proteins (Eriksson & Albrektsson, 1983, Li et al, 1999).
A Visual Basic Program to Calculate Gear Features
Authors: Vavrek Edward M. 
Published: November 2021

Abstract
This paper describes a spur gear design analysis program written in visual basic. The program is used to assist engineering students in the design of spur gears, which involves many calculations and decisions. This software program simplifies and streamlines the design and selection process. Since the visual basic program is event driven, the user can go through the program by inputting values into text boxes and then initiating events by clicking on command buttons. An important feature of this program is the ability to insert pictures, tables, graphs, drawings, and figures to enhance the program functionality. Most inputs are taken from graphs, charts, or tables so the user knows where and how the information is obtained and used. Outputs are shown with their appropriate figures, drawings, or calculation formulas to assist the user in understanding how the output was derived. The software has the advantage of making minor changes to the problem quickly and easily to see how the output is affected.
Blind Image Restoration for Ultrasonic C-Scan Using Constrained 4th Order Cumulants
Authors: Qidwai Uvais , Chen Chi-Hau 
Published: November 2021

Abstract
C-Scans are ways to visualize the sample under study by utilizing the reflections from various levels of non-homogenous wave transfer within the sample. Unlike other imaging techniques, C-scan are usually constructed from the pulse-echoed A-Scans by mapping the 1D windowed signal into a point corresponding to a pixel on the C-scan by calculating its energy within the window. Hence, although the A-scans are predominantly Gaussian in nature, the spatial 1D waveforms mapping into spatial energy values, results in completely unpredictable statistical characteristics. Also, the medium characteristics incorporate distortions that are essentially due to a non-minimum phase system response. Hence, the usual Second Order Statistics (SOS) based identification and deconvolution, i.e., correlation and covariance based techniques, may not work very well in this case.
In this paper, an approach is presented to use 4th order cumulants to deconvolve the effects of blurring in the C-Scans due to above-mentioned effects. The proposed approach is completely blind to the source or the type of distortion and the formulation is purely two-dimensional. When the blurring function is modeled as an Auto Regressive (AR) process, the image is restored recursively with the application of the inverse filter based on the AR estimate. A significant improvement in the image quality has been demonstrated. Especially, the edges are detected more prominently than present in the original image. Very little or no post processing is needed to obtain the final image.
Analysis of Curved Beams by the B-Spline Field Approximation Method
Authors: Vermeulen A. H. , Heppler G. R. 
Published: November 2021

Abstract
The B-spline field approximation method is applied to the static deflection analysis of curved Euler-Bernoulli and Timoshenko beams. A formal definition of membrane locking is presented along with a simple test that allows a priori determination of a models susceptibility to membrane locking. Formulations for both types of beam models, that under certain discretizations experience membrane locking, are presented and additional formulations that can never experience membrane locking are presented for both beam models. Examples that demonstrate the efficacy of the membrane locking test and illustrate the two means of avoiding membrane locking are presented.
Epidemiological estimates and early detection of polycystic kidney disease by ultrasonographic assessment in Japan
Authors: Kobayashi Minoru , Kamai Takao 
Published: November 2021

Aims: To estimate the prevalence of autosomal dominant polycystic kidney disease (ADPKD) and provide the evaluation of new ultrasonographic criteria and clinical indicators to help its early detection.Materials and methods: A total of 30750 individuals for health check-up with abdominal ultrasonography (US) were included, in which 231 suspects of ADPKD based on the number of renal cysts were extracted. They were divided into 4 groups by the grade of suspicion (definitive, a strong suspect, a fair suspect and a weak suspect). Longitudinal data of US and renal function tests were compared between the groups.The estimated prevalence rate was 0.068% from the study subjects. The level of eGFR did not differ between the definitive and suspects, while the annual estimated glomerular filtration ratio (eGFR) decline was significantly larger in the former (p<0.001). The subjects with growing renal cysts showed a larger annual eGFR decline than those without growth (p=0.0324). The proposed cut-off set at the first quartile of the annualized eGFR change efficiently divided the subjects according to the presence of cyst growth (p= 0.027) and the grade of suspicion of ADPKD (p=0.028).Conclusion: The prevalence rate of ADPKD was higher than the corresponding rate previously reported in Japan (0.025%), suggesting that health check-ups may be an efficient opportunity to pick up undiagnosed ADPKD. The large annual eGFR decline and the presence of growing cysts may be feasible indicators to isolate ADPKD and should be introduced into US based screening to facilitate early detectionof ADPKD.
Pathways in Paralympic Sport: An In-Depth Analysis of Athletes’ Developmental Trajectories and Training Histories
Authors: Dehghansai Nima , Pinder Ross A. , Baker Joseph 
Published: November 2021

This three-part investigation conducted a comprehensive analysis of 213 Australian and Canadian athletes’ developmental trajectories, training histories, and experiences in organized sports from 18 Paralympic sports (PS). While athletes with early-onset impairments (i.e., congenital, preadolescent) reached milestones and commenced various types of training at a significantly younger age than athletes with later-onset impairments (i.e., early adulthood, adulthood), the latter groups progressed through their careers and incorporated various trainings at a faster pace (i.e., fewer years). Preferences to certain training conditions varied between groups. Eighty-two percent of the athletes with acquired impairments had experience in able-bodied sports before the onset of their impairment, with 70% noting involvement in sports similar to their current PS. The participation rates (38%) and sport similarity (53%) were lower in PS. The amalgamation of findings from this series of studies highlights the complexity associated with PS athletes’ development and demonstrates the importance of taking an individualized approach.