bluuebunny/crossref_metadata_2025_split huggingface dataset:
Design and Implementation of a Flexible Intelligent Electronics Remanufacturing System
Authors: Fidan Ismail , Kraft Russell P. , Derby Stephen J. 
Published: December 2021

Abstract
Electronic manufacturing of circuit boards has undergone major changes in the last decade as new technologies have emerged and are perfected to replace older ones. A result of the increased board layout densities and higher levels of integration at the chip level is a dramatic increase in the value of circuit boards. The benefit is much more functionality in smaller boards, but the disadvantage is significant losses when a defective board must be scrapped. The same technology that has increased the density of the board functionality has made manual rework to correct manufacturing defects almost impossible. Higher levels of circuit integration in moving from VLSI to ULSI (Ultra Large Scale Integration) have required more pin-outs on the packages which in turn has resulted in finer lead pitches and a change from through-hole mounting to surface mounting technology (SMT). These two changes, with the decreased interchip spacing, have necessitated the use of automation to perform reliable component replacement on defective boards. This paper discusses the complexities of integrating several automation technologies into a single robotic electronic remanufacturing workcell. Involved are vision guidance, control software development, and multiple special end-effector designs for the several required steps, including defective component removal, board cleaning, solder paste dispensing, component placement, and laser soldering [1].
Impact of On-Die Discrete Heating on Thermal Performance Characteristics of Silicon Based IC Electronic Packages
Authors: Adams V. H. , Ramakrishna K. 
Published: December 2021

Abstract
Simulations for thermal characterization of electronic packages for silicon-based integrated circuit (IC) components typically assume one of the two uniform heat generation conditions. They are: (1) an isoflux condition in which heat generation is uniformly distributed over the active surface of the die, or (2) a uniform heat generation over the entire (or active) volume of the die. The use of these models may be justified due to high thermal conductivity of silicon, size of the devices on the die, and their relatively uniform spatial distribution over the entire surface of the die in the traditional silicon technologies. However, the current and future technologies are migrating towards embedded systems solutions, such as system-on-chip, and in traditional applications devices are brought in close proximity to each other for improved on-chip electrical performance. These trends result in localized regions of power dissipation on the die that would invalidate the use of traditional uniform generation models in the thermal characterization.
The present study examines the effect of discrete heat sources (as opposed to uniformly distributed sources) on the die on thermal performance and characterization of the electronic packages. For this purpose, a conjugate heat transfer problem of a memory chip in a 119 I/O flip chip ceramic and plastic ball grid array (FC-C & PBGA) package under natural and forced convection conditions. First the model is validated against experimentally measured thermal data on a 119 I/O FC-C & P BGA daisy-chain test packages with a thermal test die with uniformly distributed resistive heat source. Junction-to-ambient temperature difference predictions from the simulations are within 10% of the measurements for the uniform heating case. The validated model is then suitably modified to account for discrete heat sources and actual substrates. Results from the discrete heat sources study show a 15–20% increase in predicted junction-to-ambient temperature difference and a larger (a 10–15 °C) temperature variation across the active face of the die than for with a uniform heat source. These results call for the use of discrete heat sources in the thermal characterization of new generation of embedded silicon technologies. They also point to the need for development of test die and characterization methodologies for these technologies with discrete heat sources.
Curvature of a Film-Substrate System in the Nonlinear Deformation Range
Authors: Freund L. B. , Rosakis A. J. , Lee H. S. 
Published: December 2021

Abstract
The physical system considered is a thin film bonded to the surface of an initially flat circular substrate, in the case when a residual stress exists due to an incompatible mismatch strain in the film. The magnitude of the mismatch strain is often inferred from a measurement of the curvature it induces in the substrate. This discussion is focused on the limit of the linear range of the relationship between the mismatch strain and the substrate curvature, on the degree to which the substrate curvature becomes spatially nonuniform in the range of geometrically nonlinear deformation, and on the bifurcation of deformation mode from axial symmetry to asymmetry with increasing mismatch strain. Results are obtained on the basis of both simple models and more detailed finite element simulations. Preliminary full-field observations are reported on deformation of a 6 μm thick Al film deposited onto a 100 μm thick Si substrate subjected to thermal cycling.
Elastic Response of Rubber Double Networks
Authors: Roland C. M. , Santangelo P. G. , Mott P. H. 
Published: December 2021

Abstract
Double network elastomers are formed by twice-curing rubber, the second time while the material is deformed. When measured parallel to the curing deformation, the equilibrium modulus of a double network exceeds that of an isotropic elastomer of equal crosslink density. This difference increases with increasing strain. Despite the higher modulus, the mechanical fatigue lifetimes of double networks of natural rubber were found to be as much as a factor of ten higher than for the conventionally crosslinked rubber. The double network’s tensile strength, on the other hand, was slightly lower. Such results suggest that the conventional compromise between modulus and failure properties can be circumvented using double network rubbers. Their utilization can yield elastomers of better mechanical properties.
Strain-Temperature and Strain-Entropy Internal Constraints in Finite Thermoelasticity
Authors: Casey James 
Published: December 2021

Abstract
Starting out with the set of unconstrained thermoelastic materials, appropriate equivalence relations are introduced as a means towards defining internally constrained materials. The construction is first carried out in strain-temperature space, and subsequently in strain-entropy space. The question of the interrelationships between the two types of constraints is examined.
On the Determination of Entropy From a Scalar Potential for Special Inelastic Materials
Authors: Johnson George C. , Imam Ali 
Published: December 2021

Abstract
A known version of the second law of thermodynamics embodying the notion of dissipation is employed to obtain restrictions among constitutive response functions for two classes of inelastic bodies. It is shown that for such bodies the entropy function can be determined once the constitutive relation for the Helmholtz free energy function is specified. In addition the internal energy function is shown to depend exclusively on the temperature and the deformation gradient.
Methodology Development for Simulating Full Frontal and Offset Frontal Impacts Using Full Vehicle MADYMO Models
Authors: Deshpande Bala , TJ Gunasekar , Morris Russell , Parida Sudhanshu , Rashidy Mostafa , Summers Stephen 
Published: December 2021

Abstract
MADYMO articulated full vehicle models of the 1992 Ford Taurus, 1995 Chevrolet Lumina and the 1994 Dodge Intrepid for frontal and side impact modes have been developed and validated against test data. MADYMO (Mathematical Dynamic Model) is typically used to model occupants in the environment of the vehicle interior and thus finds application mainly in assessing occupant injuries. In this study however, MADYMO has been employed not only to model the occupants but also to represent the major load bearing structures in the vehicles. Input for the MADYMO models consisting of rigid body joint stiffness was obtained from corresponding full vehicle Finite Element (FE) models. Model validation was done by comparing the vehicle and dummy numbers with the New Car Assessment Program (NCAP) test results. Models correlated very well with both test and FE data. This modeling approach demonstrates the utility of rigid body based full car models for crashworthiness analysis. Such models result in significant saving in computational time and resources.
In this paper, we describe the simulation of two different crash modes: full frontal and offset frontal impacts using the full vehicle MADYMO models. These simulations were validated with the corresponding test results in full frontal mode and IIHS offset mode. The models are useful for simulating a variety of impact situations, for example, with different occupant sizes, occupant positions, impact velocities, and in car to car impacts for performing compatibility studies.
Development of a Finite Element Model of the Human Shoulder
Authors: Iwamoto Masami , Miki Kazuo , Sambamoorthy Babushankar , Yang King H. , King Albert I. 
Published: December 2021

Abstract
During an automotive side impact, the shoulder is likely to be the first body part that is directly impacted either by the internal structures of the vehicle or by the side airbag. Therefore, a good understanding of the injury mechanism and the kinematics of the shoulder is critical for occupant protection in side impact. Existing side impact crash dummies do not have structures that are capable of reproducing the kinematics and kinetics of a human occupant. Over the past several years, many numerical models have been developed from head to foot in an attempt to overcome the shortcomings of these crash dummies. However, relatively few attempts have been made to include the shoulder. The purpose of this study is to develop a finite element model of the human shoulder in order to achieve a deeper understanding of the injury mechanism and the kinematics of the shoulder in side impacts.
Basic anthropometric data used to develop the skeletal portion of the shoulder model were taken from a commercial data package of the human shoulder geometry (Viewpoint Datalabs). This geometry was scaled to fit a 50th percentile male occupant according to the data reported by Schneider et al. (1983). The shoulder model included the three bones of the shoulder, namely the humerus, scapula and clavicle. Each bone was modeled in two parts. The spongy bone was modeled using crushable solids and the cortical bone was modeled using damageable shell elements. The model also includes major ligaments, which form the acromioclavicular and sternoclavicular articulations. The deltoid muscle, which was modeled by crushable solids in order to absorb part of the impact energy, was added to this model for lateral impact simulations. This shoulder model was then integrated with a human thorax model developed by Wang (1995), along with other preexisting models of other parts of the human anatomy. Material properties for the model were taken from the literature. Experimental data obtained from lateral impact sled tests of 17 cadavers conducted at Wayne State University were used to validate the model. Impact forces in four regions, specifically, the shoulder, thorax, abdomen and pelvis, were calculated by the model and were compared with forces obtained experimentally from rigid wall impacts at 6.7m/s and padded wall impacts at 8.9m/s.
Analytical Modeling of Forced Convection in Slotted Plate Fin Heat Sinks
Authors: Teertstra P. , Culham J. R. , Yovanovich M. M. 
Published: December 2021

Abstract
Analytical models are developed for the average heat transfer rate in forced convection-cooled, slotted fin heat sinks. These models for the upper and lower bounds can be used to investigate the effects of slot size and placement on heat sink performance. Experimental measurements are performed for a variety of slot configurations over a range of Reynolds numbers, and these data are compared with the proposed analytical models. An approximate model is proposed that predicts the experimental results for the average heat transfer rate to within a 12% RMS difference.
Modeling the f and j Characteristics of the Offset Strip Fin Array
Authors: Muzychka Y. S. , Yovanovich M. M. 
Published: December 2021

Abstract
New models for predicting the thermal-hydraulic characteristics of offset strip fin arrays are developed. These models are developed by combining the asymptotic behaviour for the laminar and turbulent wake regions. Models in these two regions are developed by considering the offset strip fin as an array of short ducts or channels. The proposed models are compared with published experimental data for nineteen configurations of the rectangular offset strip fin. Model predictions are within ± 20 percent for 96 percent of friction factor data and 82 percent for Colburn j factor data. Extension of the new models for offset strip fins having non-rectangular subchannels is also discussed.
Laminar Mixed Convection in the Entrance Region of a Helical Pipe
Authors: Zheng B. , Lin C. X. , Ebadian M. A. 
Published: December 2021

Abstract
A fully elliptic numerical study is performed to investigate the buoyancy-affected, three-dimensional laminar flow and heat transfer in the entrance region of a helical pipe at a constant wall temperature. The Control Volume Method with second-order accuracy is used to numerically solve the three-dimensional fully elliptic governing equations for the problem. The O-type non-uniform structure grid system is adopted to discretize the computation domain (two complete turns of a helical pipe) in this study. The Bossinesq approximation is applied to deal with the buoyancy effect caused directly by density difference. The developments of flow and temperature fields, profiles and characteristics at different Gr/Re2 are given and discussed. The computed results reveal that the entrance region of heat transfer is increased rapidly when buoyancy force is considered. In the meantime, the buoyancy effect on the average Nusselt number and friction factor is greater at the entrance region of the helical pipe, but it gradually becomes weaker further downstream.
Natural Convection Heat Transfer in a Vertical Air Layer Partitioned Into Cubical Enclosures of Finite Wall Thermal Conductivity and Thickness
Authors: Yamaguchi Y. , Asako Y. 
Published: December 2021

Abstract
Three-dimensional natural convection heat transfer characteristics in a vertical air layer partitioned into cubical enclosures of finite wall thermal conductivity and finite thickness were obtained numerically. The outer surfaces of the enclosure are prescribed at different temperatures. These walls are often encountered in applications such as door panels and thermal insulation boards. The analyses were performed for finite wall thickness and conductivity, for Ra = 104 and 105 and for a wide range of wall thickness and thermal. The results were presented in form of temperature distributions and contour plots of Num and Qwall/Qtotal. From comparison of the results with ideal boundary conditions, a correlation for heat transfer for partitioned walls was developed. It was shown from the results that the ratio of heat transfer into the partition walls to the total heat transfer from the hot wall is a function of the product of wall thermal conductivity and thickness.
Computation of Discrete-Hole Film Cooling by a Near-Wall Second-Moment Turbulence Closure
Authors: Chen Hamn-Ching , Wei Gengsheng , Han Je-Chin 
Published: December 2021

Abstract
A multiblock Favre-Averaged Navier-Stokes (FANS) method has been developed in conjunction with a chimera domain decomposition technique for investigation of flat surface, discrete-hole film cooling performance. The finite-analytic method solves the FANS equations in conjunction with a near-wall second-order Reynolds stress (second-moment) closure model and a two-layer k-ε model. Comparisons of flow fields and turbulence quantities with experimental data clearly demonstrate the capability of the near-wall second-moment closure model for accurate resolution of the complex flow interaction bewteen the coolant jet and the mainstream. The near-wall second-moment anisotropic model provides better agreement in adiabatic film effectiveness prediction than the two-layer k-ε model.
Energy Conversion in Multilayer Thin-Film Structures for Thermionic Cooling
Authors: Zeng Taofang , Chen Gang 
Published: December 2021

Abstract
A new type of multilayer thermionic coolers with varying barrier heights is proposed in this article. Based upon the assumption of ballistic electrons in the filters and thermalized electrons in the bases, we analyzed the energy balance at each stage. As the heat flux increases at later stages, the barrier height should also increase. The optimum structure is obtained by a trial-and-error method. Calculation results show that the coefficient of performance does not change significantly with the number of stages of the thermionic cooler. The heterojunction structure with varying barrier heights have a slightly higher COP than the one with a fixed barrier height.
Experimental Correlation of a Thermal / Fluid Dynamic / Electrical Performance Model of a Multiple-Tube, Vapor-Anode AMTEC Cell
Authors: Hendricks Terry J. , Huang Chendong , Giglio Joseph C. 
Published: December 2021

Abstract
An AMTEC (Alkali-Metal Thermal-to-Electric Conversion) cell performance analysis model described by Hendricks et al. (1998) has been correlated with experimental data by comparing its predictions for Beta” alumina solid electrolyte (BASE) and evaporator temperatures, voltage, power output, and conversion efficiency with experimental measurements on two versions of a PX-6 AMTEC cell. The critical features of this AMTEC cell model, the PX-6 experimental set up and testing, and the model correlation PX-6 test data are discussed in this work. Model prediction/test data comparisons are presented across a wide range of current-voltage conditions and hot side temperatures for two significantly different cell lengths. Cell model predictions demonstrate good agreement with experimental PX-6 test data in simultaneously predicting BASE tube and evaporator temperatures, the onset of sodium (Na) condensation in the BASE tubes, current-voltage characteristics, and power output in high current ranges (i.e., &gt; 1.5 A). The model also has demonstrated good capability to predict cell conversion efficiency at high currents when Na is not condensing in the BASE tubes. The good model prediction/test data comparisons have demonstrated the progress in developing this cell performance model and increased confidence in its technical foundations, algorithm implementation, and capability to predict AMTEC cell performance. The AMTEC cell model’s capability to simultaneously predict many critical cell performance parameters across a wide range of hot side temperatures, at high current conditions, and different cell lengths demonstrates the progress that has been made in its development. It has demonstrated good predictive capability, utility, and flexibility as a performance design and analysis tool for sophisticated AMTEC cell design. Testing limitations prevented testing at low current levels (i.e., &lt; 1.5 A), so future experimental validation studies should focus on correlating model predictions at low currents.
A New Model for Two Phase Multicomponent Displacements Honouring Ganglia and Droplets
Authors: Bedrikovetsky Pavel 
Published: December 2021

Abstract
During two-phase flow through porous media, a non-wetting phase may be present simultaneously as a continuous phase and as trapped isolated ganglia. Mass exchange between these two parts of the non-wetting phase is going on by dissolution and diffusion of components through the wetting phase, the compositions of the non-wetting phase in both parts being different. Nevertheless, the traditional mathematical model for two-phase multicomponent transport through porous media assumes that the distribution of all components in the overall non-wetting phase is homogeneous.
This paper derives a new set of equations governing two-phase, three-component flow through permeable media that honours the isolated nature of a trapped residual phase. The solutions of these equations compare favourably to the results of laboratory tests. An analytic solution of the equations of the displacement of oil and water by the mixture ‘water-miscible gas’ (water-alternating-gas process) shows that a significant amount of oil remains after a miscible displacement. This observation is in contrast to the ‘traditional’ fractional flow model that predicts complete recovery of oil from the portions of the medium swept by the solvent.
Interaction Coefficient Between Ice Particles in Convective Melting of Granular Packed Bed
Authors: Jiang J. , Tao Y.-X. 
Published: December 2021

Abstract
To numerically simulate the convective melting of packed bed it is necessary to determine the thermophysical properties or their constitutive equations. One of the most uncertain values among them is the solute interaction coefficient of solid particles, which represents the interaction force between solid particles and is equivalent to the viscosity term in Navier-Stokes equations if the dirty fluid model is applied. It was found from the previous study that the solute (solid particle) interaction coefficient, μs, characterizes the solubility such as the melting rate, the distribution of ice volume fraction, the velocity of ice particle, and the melting time. In this study, a parametric study based on the two-dimensional model for the convective melting of granular packed beds (Jiang et al. 1999) is conducted to determine the sensitivity of interaction coefficient to the model prediction. The packed bed considered here is collection of ice particles of various shapes. Warm water at a constant temperature enters horizontally the bed where melting takes place. Two cases are considered. One is to consider μs as constant, and the other is to consider it as a function of the ice volume fraction. The melting rate, fluid flow velocity and ice volume fraction distribution are discussed for different interaction coefficient values. An “optimal” interaction coefficient between ice particles is determined by comparing the simulation data with experimental data (Tao et al. 1998). It is found that the melting results are most sensitive to the value of constant interaction coefficient rather than to whether it is a constant or as a function of the ice volume fraction.