bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Periodic Surface Heating Method for the Thermal Characterization of Dielectric Thin Films
Authors: Indermuehle Scott W. , Peterson Richard B. 
Published: January 2022

Abstract
This paper presents a phase sensitive measurement technique for determining two independent thermal properties of a thin dielectric film. The technique involves measuring a specimen’s front surface temperature response to a periodic heating signal produced by passing current through a 50 nm thick layer of nichrome deposited on the specimen’s surface. The temperature response is measured with a HgCdTe infrared detector operating at 77 K. The phase shift of the temperature response with respect to the heating signal is fit to an analytical model using thermal diffusivity and effusivity as fitting parameters. From these two parameters, the thermal conductivity and specific heat can be calculated. The method has been applied to 1.72 μm-thick films of SiO2 that were thermally grown on a silicon substrate. One interesting outcome stemming from analysis of the experimental data is the ability to extract both thermal conductivity and specific heat of a thin film from phase information alone. All film thermal conductivities determined so far by this method show a slight decrease with respect to the bulk values. Specific heats were found to be similar to bulk values. Both of these results are consistent with past work on thermally grown films of SiO2.
Heat Transfer in a Matrix With Embedded Particles
Authors: Vick Brian , Scott E. P. 
Published: January 2022

Abstract
The transient heat transfer characteristics of heterogeneous materials consisting of a microstructure of relatively small particles embedded in a matrix is investigated. A constitutive model is developed where heat is initially transferred to the matrix and is then transferred to small, separated particles embedded throughout the matrix. The heat exchange between the matrix and particles is characterized by a contact conductance. This physical model leads to a system of coupled diffusion equations for the matrix and particles, similar to the parabolic two-step model used to describe the electron-lattice interactions in microscale heat transfer. In the current investigation, a one-dimensional model with an applied surface heat flux is used.
A numerical solution to the coupled system of equations using the control volume based finite difference method is developed. This method readily allows for the inclusion of any combination of material properties, particle sizes and contact conductance. Case studies reveal that the property ratios and contact conductance can lead to a thermal lag where the temperature response to an applied heat flux is markedly different than that predicted with a homogeneous conduction model. An effective thermalization time can also be inferred from this modeling of the heterogeneous microstructure.
Predicting Thermal Boundary Resistance Using Monte Carlo Simulation
Authors: De Bellis Lisa , Prasher Ravi S. , Phelan Patrick E. 
Published: January 2022

Abstract
The Acoustic Mismatch Model (AMM) and the Diffuse Mismatch Model (DMM) have traditionally been used to predict the thermal boundary resistance, Rb, across the interface of two adjoining materials at temperatures well below the Debye temperatures of the materials in question. Both models, however, fall short when compared to experimental data. The development of these models involves limiting assumptions in order to simplify the mathematical evaluation. A Monte Carlo (MC) Model is proposed and developed as a compliment to the AMM and DMM models. Using the statistical approach eliminates the need of addressing complicated expressions, thereby allowing us to lift some of the limiting assumptions. Furthermore, for the first time, the AMM and DMM are combined into a single, mixed model which determines Rb based on a net heat transfer calculated from both specular and diffuse transmission. As expected, the results in this instance lay between those of the AMM and DMM models.
A Critical Evaluation of the Monte Carlo Method for Application to the Inverse Heat Conduction Problem
Authors: Ganesa-Pillai Madhu , Haji-Sheikh A. 
Published: January 2022

Abstract
The solutions of the Inverse Heat Conduction Problem using the Monte Carlo method, Green’s Function Solution Equation and the Alternative Green’s Function Solution Equation are compared. The Monte Carlo method is a simple technique that provides a method of determining the source of error and placement of sensors. However, in comparison with the exact solution, if attainable, the cost is a higher error in the solution. All the three methods use the function specification method in the sense that a functional form for the surface heat flux or temperature is assumed and the parameters defining the function are evaluated by minimizing the error functional. In the alternative method, the functional form also satisfies the boundary conditions, the unknown quantity in the problem. The input data for this comparison are experimentally measured temperatures in a stainless steel disk subjected to spray cooling.
The Function Decomposition Method and its Application in Thermal Inverse Analysis
Authors: Osborne G. E. , Frankel J. I. , Keyhani M. 
Published: January 2022

Abstract
The use of inverse analysis for both function reconstruction-estimation and thermal design problems represents a developing area for which a wealth of studies can be performed. These two classes of thermal inverse problems are both ill-posed and differ mainly in the nature of the data prescribed at the over-specified boundary surface, i.e., discrete or continuous data.
A new and robust technique is presented that eliminates the need for multiple analytical approaches. The innovative procedure, called the Function Decomposition Method (FDM), is proposed and demonstrated in this paper. This technique provides stable and accurate results without the need for specification of an external Tikhonov regularization parameter, thereby reducing the complexity of the solution algorithm. The methodology may be readily extended to nonlinear problems by utilizing quasilinearization.
The results presented in this paper focus on problems in which discrete temperature data are provided at the boundary. To illustrate the Function Decomposition Method as it is applied to inverse heat conduction, the classic Beck’s problem is considered. The first case uses exact data as input while the remaining cases employ data with noise introduced.
Inverse Radiation Heat Transfer Within Enclosures With Nonisothermal, Non-Gray Participating Media
Authors: França Francis H. R. , Oguma Masahito , Howell John R. 
Published: January 2022

Abstract
This work considers the inverse problem where both the net radiative heat flux and temperature distributions on the design surface of a rectangular enclosure are imposed, the remaining surfaces being adiabatic. The enclosure is filled with a non-gray, absorbing, emitting, non-scattering medium, whose temperature and volumetric heat generation distributions are unknown, and have to be determined such that the two specified conditions on the design surface are attained. The heat transfer is considered to be purely radiative, and is evaluated by the zoning method combined with the weighted-sum-of-gray-gases model. The resulting system of equations is non-linear and ill-conditioned. It is solved by an iterative procedure, where the truncated singular value decomposition method (TSVD) is applied at each iteration step.
Automotive Heater Core Boundary Conditions Identification
Authors: Moultanovsky Alexander V. 
Published: January 2022

Abstract
This paper centers on the first ever research of inverse problem of an automotive heating thermal system, which mostly operates in cold weather modes of Heating, Ventilating, and Air Conditioning system. Heat fluxes or heat transfer coefficients between an automotive heater core and fluids are intended to be identified by means of Inverse Heat Transfer Problem solution. The estimation of heat transfer with the inverse heat transfer methods, first and foremost makes it possible to get accurate results of heat transfer coefficient (or heat flux) because one calculates it with the most exact statistical methods on the basis of real temperature measurements. Secondly, the identified boundary conditions would be very precise since its value is calculated based on temperatures, which appear already as a product of all heat transfer between coolant and air.
Heat Transfer and Thermal Pattern in Two-Phase Flow
Authors: Hetsroni G. , Mosyak A. , Rozenblit R. , Yarin L. P. 
Published: January 2022

Abstract
This study deals with heat transfer in vertical, horizontal, and inclined tubes with water-air mixture flowing in them. We obtain and analyze a thermal pattern on the heated wall, which makes it possible to establish the connection between the flow parameters and heat transfer. The experimental technique is based on the infrared thermography of an electrically heated wall of the tube, providing both visualization of the temperature field and measurements of the local wall temperature. We consider first the results concerning a horizontal tube only. These results serve as a reference basis for the studies on inclined and vertical tubes. The heat transfer coefficient in inclined tubes is drastically enhanced, as compared to that in a horizontal one. In a vertical tube, it is observed that the streaky thermal pattern on the wall is destroyed by the bubbles. This pattern was partially recovered with slug flow. The heat transfer coefficient was observed to increase substantially.
Symbol Statistics: A New Tool for Understanding Multiphase Flow Phenomena
Authors: Daw C. S. , Finney C. E. A. , Nguyen K. , Halow J. S. 
Published: January 2022

Abstract
We discuss data symbolization as a tool for identifying temporal patterns in complex measurement signals. We describe the basic concepts involved and illustrate their application for the analysis of gas-bubble injection data. Specific issues addressed include selection of symbolization parameters, construction of symbol-sequence histograms, and statistical characterization and comparison of these histograms. We demonstrate that symbol-sequence statistics can reveal unique information about deterministic patterns. Such information may be useful for developing flow diagnostics and comparing computational models with experiments.
Observations on Chaos in Upward Gas-Liquid Flow
Authors: Langford Heather M. , Beasley Donald E. , Ochterbeck Jay M. 
Published: January 2022

Abstract
In the present investigation, statistical and chaos analysis techniques were implemented to evaluate pressure dynamics in air-water, vertical pipe flow. The purpose of the analysis is to relate the statistical and chaos measures to the flow physics. Pressure measurements were achieved in a 22 mm ID aluminum and quartz tubing test section. Four water superficial velocities (0.0055, 0.055, 0.165 and 0.329 m/s) were examined for a range of air superficial velocities. Detailed statistical and chaos results are presented for signals representing slug flow, churn flow, and annular flow. Statistical analyses included qualitative evaluation of the shape of histograms, calculation of normalized statistical moments, and implementation of a nonlinearity test. Kolmogorov entropy and attractor dimension estimates (maximum-likelihood correlation dimension and correlation dimension) comprised the chaos analysis measures. The non-integer values of maximum-likelihood correlation dimension and correlation dimension are consistent with chaotic systems. Additionally, the positive, non-infinite values of Kolmogorov entropy, ranging from 5 to 107 bits/s, provide further evidence of the chaotic nature of the air-water vertical upflow.
Application of Capacitance Sensors for Monitoring Oil-Water Separation Processes
Authors: Jaworski Artur J. , Dyakowski Tomasz , Davies Graham A. 
Published: January 2022

Abstract
This paper describes the construction and experimental evaluation of a novel capacitance based instrument for monitoring oil-water separation processes. The electronic circuitry to measure the electrical capacitance, originally developed by UMIST for tomographic applications, is based on the charge-discharge principle. The evaluation of the developed system took place in the existing transparent oil-water separator in the Pilot Plant facility at UMIST. During the experiments, the dynamic behaviour of the multiphase flow within the packed bed of inclined separator plates has been monitored in-situ and on-line for various total flow rates as well as varying oil/water ratios in the mixture. The applied capacitance sensor enabled the measurement of the thickness of oil and water layers along the length of the separator plates as well as the emulsion phase, which is a critical parameter from the viewpoint of the separator’s efficiency.
Radial Profiles of Local Solids Distribution in a High-Loaded Riser-Reactor Measured With X-Ray Computed Tomography
Authors: Wirth K.-E. , Grassler T. 
Published: January 2022

Abstract
Since years high-loaded riser-reactors have been used successfully for different commercial applications, e.g. for fluid catalytic cracking. The fundamental study of hydrodynamics of such reactors will help to improve the design and operating conditions of existing plants and may lead to higher conversion rates and selectivity. The solids concentration distribution of a riser with an inner diameter of 0.19 m and 15 m height is investigated with x-ray computed tomography with a minimum spatial resolution of 0.2 mm and 0.4 mm thickness. A number of experiments have been carried out with narrowly size distributed glass beads between 50 and 70 μm at superficial gas velocities from 2 to 7 m/s. Even at higher circulation rates obtained radial solids concentration profiles still show a typical core-annulus structure, which gets more uniform at higher elevations.
An Homogenization Method for Solid-Liquid Phase Change During Directional Solidification
Authors: Ganaoui M. El , Bontoux P. 
Published: January 2022

Abstract
Homogeneous formulation for Navier-Stokes and energy equations is extended to the directional solidification problems. The solid-liquid mixture is represented as a single continuous medium. A two-phase intermediate zone modelled as a porous medium is involved. A finite volume approximation is used with a fixed mesh. The technique is validated with respect to an interface tracking method. The applications concern the interaction of steady and oscillatory melts with the interface during Bridgman crystal growth. The amplification of oscillatory instability in the melt is studied in the case of inverted Bridgman configuration (heated from bellow). Various solutions (steady symmetric and asymmetric, time-periodic, aperiodic ...) are analyzed.
Non-Intrusive Heat Transfer Coefficient Determination in Highly Porous Metal/Ceramic Foams
Authors: Jones Stanley , Catton Ivan 
Published: January 2022

Abstract
An experimental program has been developed by which one may non-intrusively measure the heat transfer coefficient of highly porous metal/ceramic foams. Under steady one-dimensional flow conditions, the solid phase is subjected to a step change in heat generation rate via induction heating. By measurement of the gas phase temperature response, one may determine the heat transfer coefficient based upon the volume-averaged equations for gas and solid phase energy. These equations are developed and solved numerically to determine the heat transfer coefficient from the gas phase temperature response.
The media in question is a highly porous (0.75–0.90) reticulated structure that, due to small gas pathways (25–160 pores per linear inch) and narrow solid ligaments, makes direct temperature measurement impractical, intrusive and inaccurate. Not only does this technique alleviate the need for complicated gas and solid phase temperature measurements, the heat generation rate does not require determination. Therefore, at no point is the fluid/solid porous media interaction disturbed by the presence of temperature sensors and the experimentalist avoids the calibration difficulty of an inductively-coupled, sample specific, heat generation system.
Non-Intrusive, Spatially Resolved Temperature Measurements Using Coherent Anti-Stokes Raman Spectroscopy (CARS)
Authors: Kearney Sean P. , Lucht Robert P. , Jacobi Anthony M. 
Published: January 2022

Abstract
This paper describes the use of a dual-broadband, pure-rotational coherent anti-Stokes Raman spectroscopy (CARS) technique for non-intrusive, spatially resolved temperature measurements in convective-heat-transfer boundary layers. CARS is an optical, laser diagnostic technique that has often been used for temperature and species concentration measurements in high-temperature combustion applications. This work is one of the first applications of CARS to convective heat transfer. The basics of the CARS technique are discussed and the method is compared to other temperature measurement techniques used in convective-heat-transfer work. Dual-broadband, pure-rotational CARS was used to measure mean temperature profiles in a low-Reynolds-number, turbulent boundary layer. Shot-averaged temperature data were acquired as close as 50 μm (±25 μm) to the wall, with a spatial resolution of 50 μm normal to the heat transfer surface, and a precision limit of ±4 K. Results, presented for three representative Reynolds numbers, display good agreement with the thermal law of the wall for zero-pressure-gradient flows.
MRI Model Generation and Inverse Tumor Temperature, Vascular Flow and Perfusion Estimation During Hyperthermia Using a Computational Steering Tool: SCIRun
Authors: Shelkey J. D. , Luke E. J. , Weinstein D. , Roemer R. B. , Clegg S. , Johnson C. 
Published: January 2022

Abstract
SCIRun (Johnson and Roemer, 1997), a general framework for computational steering, is currently being modified to become a universally applicable and flexible package for simulating hyperthermia treatments. This package will integrate a highly interactive user interface with the following five modular programs: 1) the creation of a finite element mesh of either patient anatomies from medical imaging procedures or idealized anatomies from computational theoretical geometries; 2) the creation of a power deposition model applied to the FE mesh; 3) the solution of the resulting system of equations for the tissue temperatures; 4) the use of inverse techniques to estimate unknown parameters of the governing equation and 5) the visualization of the resulting solution. The first application of this package will be to investigate the hypothesis that pretreatment MR perfusion distribution measurements can be scaled to accurately simulate hyperthermia treatment temperatures using Pennes bio heat transfer equation (Pennes, 1948).
Model for Ultrasonic Heating of Chest Wall Recurrences
Authors: Moros Eduardo G. , Fan Xiaobing 
Published: January 2022

Abstract
Ultrasonic and biothermal numerical models for a simplified 3D chest wall anatomy were developed for a more accurate analysis of power deposition patterns and resulting temperature distributions during hyperthermic therapy of recurrent breast cancer. Four different media were considered: water, muscle tissue, bone tissue (ribs and cartilage), and lung tissue. Results are presented for planar insonation at normal incidence in a typical chest wall section at 1.0 and 3.5 MHz; frequencies that are routinely used clinically. Transient profiles show that the initial rate of temperature rise in bone tissue is much larger than in muscle tissue; however, the temperature difference between these two media decays after the first two minutes of insonation. Steady state results showed that the highest temperatures were induced at the soft tissue-bone interfaces and inside the bone tissue at 1.0 MHz, while at 3.5 MHz these were located in the muscle tissue a few mm in front of the bone. Strategies for treatment planning and optimization are discussed.
Effect of Fluid-Mechanical and Chemical Environments on Cell Function and Tissue Growth: Experimental and Modeling Studies
Authors: Neitzel G. Paul , Nerem Robert M. , Sambanis Athanassios , Smith Marc K. , Wick Timothy M. , Brown Jason B. , Hunter Christopher , Jovanovic Ivana , Malaviya Prasanna , Saini Sunil , Tan Sanda 
Published: January 2022

Abstract
Bioreactors are widely used for the growth and maintenance of tissue-engineered constructs. In this paper, we report on work directed toward a better understanding of the chemical and fluid-mechanical environments that are needed to enhance cell function and tissue growth in bioreactors. We have conducted cell-growth studies in well-controlled flow conditions that indicate the effect of shear stress and oxygen tension on cellular function. In more complicated bioreactors, like the NASA rotating-wall vessel bioreactor, we have done experimental and numerical fluid-mechanical studies that quantify the velocity and shear-rate fields near a three-dimensional construct suspended by the flow inside the bioreactor. All of these results will be used to develop the tools needed to properly design and operate bioreactors for the optimal growth of tissue substitutes.
Effects of Fluid Dynamics and Mass Transfer on Cell Migration and Growth in Confined Geometry
Authors: Peng Ching-An 
Published: January 2022

Abstract
We consider a mathematical model of the physical and biological processes involved in the bioreactors for cultivating tissues. In a laminar flow duct bioreactor, the Navier-Stokes and convective-diffusion equations are solved to obtain the concentration distribution of chemoattractant secreted from the stromal cells. Then, it is concoitmently used to solve the proposed chemotactic model and stem cell growth kinetics. The simulation results elucidate the spatio-temporal distribution of cells is governed by the interaction of cell chemotactic migration and cell mitosis. A dimensionless number that balances these two effects predicts the extent of non-uniformity in duct chambers. That is, if the directed cell migration rate is much larger than the cell growth rate, the cells will have enough time to move toward the side walls and proliferate rapidly causing prominent non-uniform growth. On the contrary, if the directed cell migration rate is much smaller than the cell growth rate, the cell growth on the cell bed is in comparison more uniform.
Towards the Understanding of Blood Perfusion in Tumor Vascular Networks Using Contrast-Enhanced MRI and Invasion Percolation
Authors: Craciunescu Oana , Clegg Scott T. 
Published: January 2022

Abstract
Accurate knowledge of the hyperthermia induced power deposition and temperature patterns are necessary to optimize the hyperthermia dose. A critical factor influencing the hyperthermia induced temperature distribution is the tumor blood perfusion. Hence, perfusion information must be available to optimize the hyperthermia therapy dose. Previous efforts to describe the tumor blood perfusion distribution for thermal analysis have relied upon the “classical” perfusion model of a highly perfused periphery and a necrotic core. However, biological structures, i.e. tumor perfusion, often cannot be described with such a straightforward Euclidean framework. To describe the irregular and fragmented non-Euclidean patterns of the tumor blood perfusion, fractal geometry is used. In particular, it has been shown that the fractal dimension of two-dimensional vascular networks resembles that of percolation clusters. In this paper, dynamic contrast-enhanced MRI is used to obtain two- and tree-dimensional images of the perfusion distribution in six canine tumors. The wash-in component of the MRI contrast signal intensity is depicted as a percolation cluster. Fractal characteristics are determined for each two- and three-dimensional percolation cluster. It is concluded that the blood perfusion in a two-dimensional tumor vessel network has a fractal structure, regardless of the tumor type and size. A preliminary three-dimensional analysis is presented that also shows a fractal structure.