bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sub-Continuum Simulations of Heat Conduction in Silicon-on-Insulator Transistors
Authors: Sverdrup Per G. , Ju Y. Sungtaek , Goodson Kenneth E. 
Published: December 2021

Abstract
The temperature rise in compact silicon devices is predicted at present by solving the heat diffusion equation based on Fourier’s law. The validity of this approach needs to be carefully examined for semiconductor devices in which the region of strongest electronphonon coupling is narrower than the phonon mean free path, Λ, and for devices in which Λ is comparable to or exceeds the dimensions of the device. Previous research estimated the effective phonon mean free path in silicon near room temperature to be near 300 nm, which is already comparable with the minimum feature size of current generation transistors. This work numerically integrates the phonon Boltzmann transport equation (BTE) within a two-dimensional Silicon-on-Insulator (SOI) transistor. The BTE is coupled with the classical heat diffusion equation, which is solved in the silicon dioxide layer beneath a transistor with a channel length of 400 nm. The sub-continuum simulations yield a peak temperature rise that is 159 percent larger than predictions using only the classical heat diffusion equation. This work will facilitate the development of simpler calculation strategies, which are appropriate for commercial device simulators.
Design and Analysis of a Meso-Scale Refrigerator
Authors: Ashraf N. S. , Carter H. C. , Casey K. , Chow L. C. , Corban S. , Drost M. K. , Gumm A. J. , Hao Z. , Hasan A. Q. , Kapat J. S. , Kramer L. , Newton M. , Sundaram K. B. , Vaidya J. , Wong C. C. , Yerkes K. 
Published: December 2021

Abstract
The preliminary design and analysis of a meso-scale refrigerator is presented here. The device is to be designed out of layers of silicon wafers bonded together and is to be fabricated through the techniques of microelectronics. The intended application of the device is an integrated heat removal system for electronics or photonic chips or modules. The paper presents a functional decomposition of the entire system, thermodynamic feasibility analysis, alternative configurations for two of the functions: actuation and compression, and parametric analysis for two alternative candidates for compressor actuation.
A set of reasonable design requirements is first formulated. Overall function of the devices is decomposed into nine major sub-functions. Comparison of different alternatives for compression and actuation suggests that electrostatic actuation integrated with centrifugal compression is a viable option. Two different ways to implement electrostatic actuation are considered in details: variable capacitance motor and electrostatic induction motor. A set of design relations and criteria needed to obtain the optimal design of each motor is presented along with a discussion on relative effects of the main design parameters.
Laser-Induced Fluorescence Measurements in Venturi-Cascaded Propane Gas Jet Flames
Authors: Qubbaj Ala R. , Gollahalli S. R. 
Published: December 2021

Abstract
“Venturi-cascading” technique is a means to control pollutant emissions of diffusion flames by modifying air infusion and fuel-air mixing rates through changing the flow dynamics in the combustion zone with a set of venturis surrounding the flame. A propane jet diffusion flame at a burner-exit Reynolds number of 5100 was examined with a set of venturis of specific sizes and spacing arrangement. The venturi-cascading technique resulted in a decrease of 33% in NO emission index along with a 24% decrease in soot emission from the flame, compared to the baseline condition (same flame without venturis). In order to understand the mechanism behind these results, Laser Induced Fluorescence (LIF) spectroscopy was employed to study the concentration field of the radicals (OH, CH and CN) in the baseline and venturi-cascaded flames.
The LIF measurements, in the near-burner region of the venturi-cascaded flame, indicated an average decrease of 18%, 24% and 12% in the concentrations of OH, CH and CN radical, respectively, from their baseline values. However, in the mid-flame region, a 40% average increase in OH, from its baseline value, was observed. In this region, CH or CN radicals were not detected. The OH radical, in the downstream locations, was mostly affected by soot rather than by temperature. In addition, prompt-NO mechanism appeared to play a significant role besides the conventional thermal-NO mechanism.
Measurements of Fire Whirls From a Single Flame in a Vertical Square Channel With Symmetrical Corner Gaps
Authors: Satoh Kohyu , Yang K. T. 
Published: December 2021

Abstract
One of the most destructive forces in large urban fires is the occurrence of fire whirls. Despite the relatively recent experimental and numerical simulation studies on the global behaviors of small-scale whirling fires, much of the whirling fire phenomena still remain unknown. The purpose of this experimental study is to examine closely the detailed structures of the velocity and temperature fields in a stable whirling flame generated in a vertical square channel with symmetrical corner gaps by both physical measurements using conventional means and by quantitative observations using both a high-speed motion camera and a thermographic infrared camera. The results showed a rather complex non-uniform velocity and temperature field in the lower half of the whirling flame and could provide an important basis to validate the fire field models for the study of real large-scale fire whirls.
Nuclear Safety Analysis for Cassini Accidental Earth Reentries
Authors: Baker Richard L. , Nelson Duane A. 
Published: December 2021

Abstract
An engineering analysis model for predicting the response and potential breakup of Cassini spacecraft nuclear fuel modules during accidental Earth reentries is described. Physical aspects considered include aerodynamics, aerothermodynamics, thermostructural loads and ablation response. The extreme velocity, 19 km/sec, of an inadvertent reentry during the Earth gravity-assist flyby requires the development of a new model to predict the dominant radiative heating rates. Uncertainty estimates are established for each of the major factors in the model. Sensitivity analyses are also carried out to determine the effect of off-nominal environments on the predicted outcome. This allows output from the calculations to be expressed as a probability density function for atmospheric fuel release. It is concluded that 18 to 36 percent of the nuclear fuel contained in the spacecraft will be released as respirable material if reentry occurs.
Incorporating Risk Concepts Into Performance-Based Building and Fire Regulation Development
Authors: Meacham Brian J. 
Published: December 2021

Abstract
As the United States transitions to performance-based building and fire regulations, it will become increasingly important to incorporate risk concepts into the regulations. However, there is a general lack of acceptance of the concepts of risk and risk analysis by the building and fire communities. There are many reasons for this, including a lack of consensus on risk characterization and quantification, inadequate expressions of acceptable risk limits, a lack of risk analysis tools and methods tailored to building and fire safety, and a lack of guidance for addressing uncertainty. As a means to begin addressing these issues, a research project is underway with the aim of outlining a process for identifying, characterizing, and incorporating risk concepts and analysis methods into building and fire regulation development. This paper presents outcomes of the research project that are being evaluated and incorporated into the development of the International Code Council’s Performance Building Code.
Drag Reduction of Surfactant Solutions for an Enclosed Rotating Disk
Authors: Ogata Satoshi , Watanabe Keizo 
Published: December 2021

Abstract
Recently, many studies on surfactant solutions have been conducted for drag reduction in a circular pipe flow. However, currently there are very few studies on rotating disks in the solutions. In this study, drag reduction for an enclosed rotating disk in surfactant solutions was clarified experimentally. Experiments were carried out to measure the torque acting on one side of a rotating disk, using a torque measurement device located at the top of the rotating shaft. Test surfactant solutions were Ethoquad O/12 at concentrations of 50, 100 and 200ppm. The temperatures of solutions were 18°C and 28°C. The clearances between the disk and the stator were 10mm and 20mm. It was shown that the Reynolds number at the transition point increased with increasing concentration and temperature of these solutions. The maximum drag reduction ratio was about 41% in 200ppm Ethoquad O/12 solution at 28°C.
Experimental Procedures of Characterizing the Viscoelastic Properties of Certain Materials
Authors: Murty V. Dakshina 
Published: December 2021

Abstract
Experimental procedures for characterizing the material properties of viscoelastic materials are proposed. The procedures described are based on extrusion process and squeeze flow process. The fundamental features within each of these procedures are discussed in detail. If the material is assumed to be either a generalized Newtonian fluid or Bingham plastic, the relevant parameters are the viscosity and yield stress. The results of the experiments on these two properties are shown along with the effects of temperature on the yield stress are discussed.
Optimization of Adhesively Bonded Single Lap Joints by Adherend Notching
Authors: Sancaktar Erol , Simmons Sean R. 
Published: December 2021

Abstract
The effect of adherend notching on the joint strength/failure and joint deformation behavior of single lap joints was investigated. First, a parametric study was conducted using Finite Element Analysis (FEA). The results of the parametric study were used to select the most promising lap geometries for further study. Next, more detailed FEA were conducted on the selected lap geometries. This data was compared with the experimental tensile test results to assess the applicability of different failure criteria.
On Crack Growth in Composite Cylindrical Shells
Authors: Rasheed Hayder A. , Tassoulas John L. 
Published: December 2021

Abstract
Interfacial defects, in the form of cracks or layer separation, may occur in composite cylindrical shells during the manufacturing process, transportation or service life. Such defects are expected to affect the integrity of laminated composite structural elements and may reduce their capacity to resist the applied loads. In this article, the growth of pre-existing cracks in moderately thick composite cylinders is studied for the case of externally applied fluid pressure. The cracks considered separate thick layers, which are unlikely to buckle locally prior to the final collapse of the structural component. The potential of growth is assessed by computing the energy release rate. It is found that any initial out-of roundness imperfection introduces a shear force at the crack tip by causing the cross section to ovalize slightly. The energy release rate is found to vary exponentially with the applied pressure, when geometric nonlinearities are considered. The analysis is applied to a carbon/glass-fiber hybrid composite tube and the parameters influencing growth are examined. Crack length, through the thickness location, circumferential location relative to the ovalization orientation and the amount of imperfection are found to control the nature of growth. Unstable as well as stable crack growth and arrest cases are observed for various combinations of these parameters.
A Study on the Constitutive Law for Porous Solids With Pressure-Sensitive Matrices and on the Material Behavior of Rubber-Toughened Epoxies
Authors: Jeong Hyun-Yong 
Published: December 2021

Abstract
A macroscopic yield criterion for porous solids with pressure-sensitive matrices modeled by Coulomb’s yield criterion was obtained by generalizing Gurson’s yield criterion with consideration of the hydrostatic yield stresses for a spherical thick-walled shell and by fitting the finite element results of a voided cube. The macroscopic yield criterion is valid for negative mean normal stresses as well as for positive mean normal stresses. From the yield criterion, a plastic potential function for the porous solids was derived either for plastic normality flow or for plastic non-normality flow of pressure-sensitive matrices. In addition, elastic relations, an evolution rule for the plastic behavior of the matrices, a consistency equation and a void volume evolution equation were presented to complete a set of constitutive relations. The set of constitutive relations was implemented into a finite element code ABAQUS to analyze the material behavior of rubber-toughened epoxies. The cavitation and the deformation behavior were analyzed around a crack tip under three-point bending and around notch tips under four-point bending. In the numerical analyses, the cavitation of rubber particles was considered via a stress-controlled void nucleation model. The numerical results indicate that a reasonable cavitation zone can be obtained with void nucleation being controlled by the macroscopic mean normal stress, and a plastic zone is smaller around a notch tip under compression than under tension. These numerical results agree well with corresponding experimental results on the cavitation and plastic zones.
Computations of Three-Dimensional Viscous Flow Through Turbine Blade Passage
Authors: Xiao Yumin , Amano R. S. 
Published: December 2021

Abstract
An implicit 3-D solver for computations of viscous flow has been developed and the computations of the flow through a blade passage are presented. The validation cases include subsonic and transonic viscous flows in C3X cascade. Results for these turbine cascade flows are presented and compared with the experimental data. Computed pressure distributions on blade surfaces show good agreement with the published experimental data. From these computations it was found that the proposed method possesses good convergence characteristics and can be extended to unsteady flow calculations. Three-dimensional calculations show that the flow pattern in the trailing edge is quite complicated. There appear a couple of sinks near the trailing edge caused by the endwall vortices. The change of the flow pattern was clearly observed at several vertical planes away from the endwall. It was also demonstrated that the secondary flow mechanism in a transonic cascade exhibit different patterns from those in a subsonic case.
New Apparatus and Blower Centrifugal Fan Design Features to Improve its Performance
Authors: Botros Monier B. , Hanna Dorothy F. , Boulos Jasmine E. , Lai Ming-Chia 
Published: December 2021

Abstract
Different design philosophies of a blower centrifugal fan blades and hub are evaluated by airflow performance, computational fluid dynamic analysis (CFD) and experimental Laser Doppler Velocimetry (LDV). A design criterion of fan blade, vanes, channels is developed to eliminate or minimize air separation from the blades suction side. The effect of the fan hub design on the air radial velocity profile is discussed.
A new apparatus is developed to control the air flow field at the blower inlet ring. It directs the air to flow in radial directions at the entrance of the fan blade passages, channels.
The blower systems with the new features operates at high mechanical efficiency over a broad range of airflow rate in different blower scroll sizes. Its peak static efficiency reaches 62% and total mechanical efficiency 68%, which is 5 to 10% above efficiencies of previous designs. As a result, power consumption is reduced by 7–15% through the operating range.
Computerized Model of Transition in Circular Pipe Flows: Part 2 — Calculation of the Minimum Critical Reynolds Number
Authors: Kanda Hidesada 
Published: December 2021

Abstract
From the conclusions of the previous paper, Part 1, it is clear that the transition occurs in the entrance region and the critical Reynolds number takes the minimum value of about 2000 for the case of a straight pipe. In the entrance region, the velocity profile changes from a uniform distribution at the pipe inlet to a parabolic one at the entrance length. Kanda and Oshima (1998b) found that in the entrance region, the radial component of the curl of vorticity multiplied by (2/Re), which we call the normal wall strength, works as an acceleration force together with the continuity equation, and that the normal wall strength decreases inversely as the Reynolds number increases. Hence, the onset of the transition should depend on whether or not the acceleration power provided by the normal wall strength exceeds a required value. In this study the author calculated the acceleration power via finite difference calculations, and thus obtained the minimum critical Reynolds number of 2040 when using J0 = 101 grid points, and 2630 when using J0 = 51.
Simulation of Transient Cavitating Water-Hammer Pipe Flow
Authors: Qin Jian-Rong , Yu S. T. John , Lai Ming-Chia 
Published: December 2021

Abstract
Direct calculations of the transient cavitating water-hammer pipe flows using the Space-Time Conservation Element and Solution Element method, or the CE/SE method for short, is reported. The principles of the CE/SE method is treating space and time as one entity, and the calculation of flow properties is based on the local and global space-time flux conservation. As a contrast to the modern upwind schemes, no Riemann solver is used, thus the logic of the present scheme for cavitating flows is much simpler. Two numerical examples are reported in this paper: (1) a hydraulic shock problem, and (2) a cavitating pipe flow. For the hydraulic shock problem, we demonstrate the capability of the CE/SE method for capturing contact discontinuities in cavitating fluids. For the pipe flows, a two-phase homogeneous equilibrium cavitation model is employed. In both cases, numerical results compared favorably with the experimental data and analytical solution.
Space Weather Simulation on Networks of Workstations
Authors: Freitas Christopher J. , Crowley Geoffrey 
Published: December 2021

Abstract
Space weather refers to the complex phenomena that develop in the near-earth region of space and the upper layers of earth’s atmosphere. Presented in this paper are the elements required to develop a parallel computer algorithm for the real-time simulation of this highly dynamic region of space. The architecture developed for this parallel algorithm is based on Networks of Workstations connected by highspeed data links, and executed using the Parallel Virtual Machine library. This paper reviews the progress completed in developing a real-time analysis system for prediction of upper-atmospheric conditions.
A Parallel Adaptive Fast Multipole Method for High Performance Vortex Method Based Simulations
Authors: Collins James P. , Dimas Athanassios A. , Bernard Peter S. 
Published: December 2021

Abstract
A fast vortex method for the simulation of turbulent flows based on a parallel implementation of the Fast Multipole Method (FMM) is presented. The vortex method includes a hybrid vortex filament/sheet representation of the flow field, a vortex filament creation model that imitates the physical vortex self-replication process, and a hairpin removal and reconnection mechanism to limit the number and scale of vortical structures to those that are dynamically essential. The FMM, which is used to reduce the operation count in computing the velocity field, is the main focus of this paper. Two related FMM methods, referred to as the uniform and the adaptive FMM, are described. Both methods are parallelized using the Message Passing Interface (MPI) library, and timings for single and multiple processor calculations are given. Results are presented from a simulation of the flow past a prolate spheroid in a uniform stream at 30° angle of attack.
Design and Operation of a Droplet Deposition System for Freeform Fabrication of Metal Parts
Authors: Tseng Ampere A. , Lee Munhee , Zhao Bosen 
Published: December 2021

Abstract
Based on a linear stability theory for liquid jets, the design of a droplet generator system is presented for freeform fabrication. The linear stability theory of forming droplets is first reviewed and its suitability to the present droplet deposition system is then discussed. The analytical formulae for predicting droplet size and break-up length at optimal conditions are developed. Based on the present formulation, a droplet generator is designed and built to make wax and tin alloy droplets. Experiments have been conducted at a wide range of jet velocities, frequencies, and droplet sizes. Good agreements are found between the analytical predictions based on the linear theory and experimental results. It has also been found that using the present design and procedure recommended, the droplet sizes can be controlled having a size deviation of less than 3 % and the variation of the deposited layer can be managed within 3% of its width deposited.
Prediction of Phase Segregation During Mold Filling of Semi-Solid Slurries
Authors: Mat Mahmut D. , Ilegbusi Olusegun J. 
Published: December 2021

Abstract
Phase segregation during the mold filling of semisolid slurry (Sn-15%Pb) is numerically investigated under non-isothermal conditions. The effects of operating parameters on the phase segregation including inlet velocity, initial solid fraction, heat transfer rate, mold geometry are considered. The semi-solid slurry is considered a non-Newtonian fluid below a critical solid fraction (fcr) and a viscoplastic medium saturated with liquid phase above the critical solid fraction. A group of particles are introduced at the mold inlet and phase segregation is studied by following the trajectories of these particles. The sharp property change at the slurry air interface is resolved with Van Leer numerical method. It is found that phase segregation is significantly affected by processing parameter. The segregation decreases with high inlet velocity, low heat transfer rate from the mold wall and cylindrical mold geometry.
Role of sediment in generating contemporaneous, diverse “type” granitoid magmas
Authors: Li Shan , Miller Calvin F. , Tao Wang , Xiao Wenjiao , Chew David 
Published: December 2021

Abstract
Granite typology categorizes granitoid rocks based upon distinguishing characteristics that are interpreted to indicate sources, conditions of generation, and, by implication, tectonic setting. Complexities of elemental and isotopic geochemistry, however, commonly preclude simple typological interpretation and suggest more complex petrogenetic histories. Granitoids from the Songpan-Ganzi terrane in the eastern Tibetan Plateau were emplaced within a short interval (~15 m.y.). They display mineralogical and geochemical characteristics that are consistent with a wide range of proposed typologies (I-, S-, and A-type; high Ba-Sr and adakitic variants). Despite their close spatial and temporal association, these granitoids exhibit diversity in geochemical characteristics that indicates a broad spectrum of contributing sources. Radiogenic isotope data reveal a continuum from primitive to evolved crustal compositions; i.e., 87Sr/86Sr(t) = 0.704–0.715 and εNd(t) = +2 to −11. All granitoid “types” have variable but commonly high zircon δ18O (+4.1‰ to +11.6‰) and low whole-rock Li-B-Mg isotopic ratios compared to mantle and/or seawater (δ7Li = +5.1‰ to −3.2‰; δ11B = −10.7‰ to −16.5‰; δ26Mg = −0.23‰ to −0.59‰). These stable isotopic compositions suggest that the Songpan-Ganzi granitic magmas of all “types” had contributions from sediment, ranging from minor to dominant. The highly variable isotopic compositions of the granitoids rule out a single homogeneous source for these diverse yet contemporaneous granitoids. Their compositional variability may have been significantly influenced by sedimentary contributions, and these results demonstrate the difficulty of straightforward assignment and interpretation of granitoids using conventional typology.