bluuebunny/crossref_metadata_2025_split huggingface dataset:
Three-Dimensional Analysis of Double Rivet-Row Lap Joints: Part I — Non-Countersunk Rivets
Authors: Iyer K. , Rubin C. A. , Hahn G. T. 
Published: November 2021

Abstract
Three-dimensional finite element analysis of an elastic, double rivet-row, aluminum alloy lap joint with non-countersunk aluminum rivets, is presented. The compliance of the connection, rivet tilt, peak contact pressures and slip amplitudes, in the absence of interference and clamp-up, are described. Rivet-panel slips in the double-row assembly are between 50–60% of those calculated for the single-row case. Contrary to the expectation that the second row of rivets might reduce the stress concentration factor by half, the additional row of rivets provides a reduction of only 28%.
Parameterized Design of a Supersonic Radome
Authors: Hollis Michael S. L. 
Published: November 2021

Abstract
Future gun-launched projectiles will have higher muzzle velocities. There currently exists a need for RF transparent radome solutions with muzzle velocities near Mach numbers equal to 3 (M = 3). Future Combat System (FCS) requirements may push these velocities as high as M = 5. Assessments of aerothermal heating requirements for specific radome geometries need to be studied. Trade-off studies involving aerodynamic shape, antenna location, materials, and RF characteristics also need to be made.
The final product of this report is twofold. The first is a short-term solution using the extruded/molded plastics to manufacture a radome. The other is a guideline for a more extensive study to find several solutions for high speed, RF transparent radomes for ballistic projectiles.
Warpage Analysis of Wafers With Film Coating
Authors: Ding Hai , Ume I. Charles , Zhang Cheng 
Published: November 2021

Abstract
Wafer-level packaging (WLP) is one of the trends of electronic packaging in the 21st century. Since 1994, many companies have released WLP licenses. One of the common concerns among these various approaches is wafer warpage. Warpage of wafer tends to introduces crack or delamination during dicing and low temperature storage process. After wafer dicing, warpage could reduce the quality of each package in the long run. Many documented works indicated that in the design and implementation of WLP, some key parameters have to be carefully considered and closely controlled to ensure higher packaging quality with the minimum warpage. For the case of wafer-level flip chip, the key parameters are Young’s modulus, thickness, and coefficient of thermal expansion (CTE) of underfill.
In this research, an experimental design and statistical methods have been used to identify the model structure and parameters that are critical to the warpage of wafers. Regression models were identified based on the data obtained from finite element analysis (FEA) that is verified by shadow Moiré experiments. According to the models, the CTE, the coupling of Young’s modulus and CTE, and the coupling of thickness and CTE of underfill primarily determine wafer warpage. Further FEA and shadow Moiré experiments indicate that the models are capable of predicting of wafer warpage in the process of WLP.
Vibration-Induced Droplet Atomization (VIDA) for Two-Phase Thermal Management
Authors: Vukasinovic Bojan , Heffington Samuel N. , Smith Marc K. , Glezer Ari 
Published: November 2021

Abstract
A novel vibration induced droplet atomization (VIDA) technology is utilized in a two-phase heat transfer cell for cooling of high-power integrated circuits. VIDA is a rapid atomization process whereby discrete liquid drops (or liquid film) are placed on the surface of a diaphragm that is vibrated near or at the coupled resonance of the system. Surface waves that develop on the liquid free surface lead to rapid bursting and the ejection of secondary droplets that are propelled away from the diaphragm. The VIDA-based heat transfer cell is similar to a heat pipe in that cooling is based on the evaporation and condensation of liquid within a closed cell. However, in contrast to a heat pipe where the liquid is delivered to the evaporator by capillary transport within a wicking material, in the VIDA cell the atomized liquid droplets are propelled towards the hot surface thus eliminating the capillary transport limit that is imposed by the wicking material. The vapor condenses near an air-side heat exchanger and the condensate is delivered to the VIDA driver. The rate of atomization and therefore the heat transfer within the cell can be actively controlled and regulated. The present paper focuses on the fundamental aspects of the VIDA atomization process of a single liquid drop. It is shown that VIDA process can be either self-intensifying or self-decaying. The global features of the VIDA, spray droplet size- and velocity distributions, and their interrelation with the external driving parameters are investigated. Finally, the performance of a current prototype of VIDA heat transfer cell is discussed.
Alternative Compliant Interconnects: Thermo-Mechanical Reliability, Design and Testing
Authors: Ma Lunyu , Zhu Qi , Sitaraman Suresh 
Published: November 2021

Abstract
Two types of novel compliant interconnects are being proposed in this paper. The advantages of these two types of compliant interconnects are: accommodation of the mismatch due to different thermal expansions in electronic packages, integration with wafer-level fabrication process, low cost, fine pitch and high I/O density. The first type is a highly-compliant cantilevered spring interconnect for the next generation packaging and probing technology. To understand the reliability of the package with this novel compliant spring interconnect structure and the typical behavior of sliding contact, test vehicles with different orientations of the cantilevered springs (21 μm pitch) have been fabricated, assembled and subjected to thermal cycling test. In-situ resistance and temperature measurements have been conducted. The second type is a compliant free-standing interconnect, One-Turn Helix (OTH) structure. This structure is built as an one-turn strip helix in order to get good compliance in space. It can be fabricated through conventional photolithography-based IC fabrication process. Optimal design parameters have been identified for this structure taking into consideration the thermo-mechanical and electrical behavior of this unique structure.
A Neural-Taguchi Based Quasi Time-Optimal Control Strategy for Chemical-Mechanical Polishing Processes
Authors: Wang Gou-Jen , Chou Meng-Hsian 
Published: November 2021

Abstract
Besides the major factors such as the down force, back pressure and the rotating speed of wafer carrier, effect of polishing time is also an important issue in CMP processes. In this study, a neural-Taguchi method based cost-effectively quasi time-optimal technique for Chemical-Mechanical Polishing. (CMP) processes is developed. Key concept of this new technique is that an optimal processes parameter set is obtained through a neural networks simulated CMP processes model. Under such an optimal parameters set, the desired material removal rate (MRR) and within-wafer-nonuniformity (WIWNU) can be reached with the optimal polishing time. It has been proved by experiments that the proposed method can offer a better polishing performance while reducing the polishing time by 1/3.
Experimental Investigation on Chemical-Mechanical Polishing of Wafers With Low-Conductivity Dielectrics
Authors: Tsai Jhy-Cherng , Liu Charls , Tsai Ming-Hsih , Dai Bao-Tong 
Published: November 2021

Abstract
Low conductivity (low-k) dielectric material is used in the sandwich structure of next-generation semiconductor devices in order to reduce the RC time delay. While global flatness of wafer surface becomes critical for deep sub-micro semiconductor fabrication process, chemical-mechanical polishing (CMP) becomes one of the key technologies for planarization of wafer surface. This paper investigated the effect of the low-k material on the CMP of the SiO2 cap layer of such a sandwiched wafer. Two types of wafers, blanket wafer and wafer with circuit pattern, are designed and conducted to investigate the effects of the thickness of the low-k layer under different polishing pressures and velocities. Material removal rate (RR) and non-uniformity (NU) are used as indices of the CMP process performance. The results show that the RR and NU of wafers with low-k layer, either blanket or with circuit pattern, become better when the pressure or velocity increases. The thickness of the low-k layer, however, has only tiny effect on the RR and NU.
Reliable Low-Cost Flip Chip Interconnections
Authors: Zhong Z. W. 
Published: November 2021

Abstract
A few reliable low-cost flip chip assembly processes using gold bumps with NCA, ACF or ACP that involved daily mass production activities in the industry are reported in this paper. Some key issues of material selection and assembly for reliable low-cost flip chip interconnections are discussed. This paper also discusses reliable low-cost processes of flip chip on FR-4 using eutectic solder bumps with possible fewer process steps compared to the full assembly process. Some interesting results with respect to the reliability performance of the processes have been obtained.
Novel Experimental-Computational Method for Quantitative Applications in Electronic Packaging
Authors: Furlong Cosme , Pryputniewicz Ryszard J. 
Published: November 2021

Abstract
Rapid advances in microelectronics require design and optimization of components and packages, for new and ever more demanding applications, in relatively short periods of time while satisfying electrical, thermal, and mechanical specifications, as well as cost and manufacturability expectations. In addition, reliability and durability have to be taken into consideration. As a consequence, some of the most sophisticated analytical, computational, and experimental methods are being used for development, optimization, and quantitative characterization of electronic packages. In this paper, a novel experimental-computational method, based on combined use of recent advances in laser-based optics and computational modeling, is described and its application is demonstrated by case studies of microelectronic components subjected to electro-thermo-mechanical loads. Results of these studies show that this methodology provides an effective engineering tool for nondestructive testing (NDT) applications in electronic packaging and provides indispensable quantitative data for development, optimization, and applications in electronic packaging.
Mechanical Considerations of Shin-Etsu Elastomer As a Z-Axis Interconnect
Authors: Cox C. , Schmidt W. F. , Gordon M. H. , Marsh W. , Bates G. , Lucas M. 
Published: November 2021

Abstract
This research effort addresses the integration of a dense z-axis interconnect technology, Shin-Etsu, into a 3D thermo-mechanical multi-chip module with two to eight stack layers. Shin-Etsu is a matrix of vertical beryllium-copper wires embedded in silicone. Since it is a composite material, accurately determining Shin-Etsu’s mechanical properties is extremely important for estimating long-term reliability of the electronic package.
Five percent compression of the Shin-Etsu elastomer was specified to maintain proper electrical contact between substrates. To determine the corresponding force, Tinius-Olsen compression tests up to 15% were conducted on both single and double layer samples of Shin-Etsu. In addition, these data were used to infer Shin-Etsu’s Young’s modulus. Both series of test were also conducted with and without alumina (A12O3) to simulate the contact surface boundary condition between Shin-Etsu and the LTCC substrate (2 pieces were used for the single Shin-Etsu case, and 3 pieces were used for the 2 layer Shin-Etsu case). All compression tests follow the same trends, though the sample to sample scatter is relatively large (+/−75%). Because Shin-Etsu’s Poisson’s ratio is near 0.5 (volume is conserved), the frictional forces between the contact surfaces is important. By carefully accounting for these frictional forces, we infer a Young’s modulus for Shin-Etsu of 3.25 MPa. Using this value with the appropriate contact model (we found that a simpler model with infinite friction is suitable in our case), we are able to successfully design a two-board test vehicle which incorporates Shin-Etsu.
Effect of Rotational Speed on the Average Flow Field at the Pump/Turbine Interface of an Automotive Torque Converter
Authors: Hotho M. , Gruber M. R. , Flack R. D. , Gillies G. T. 
Published: November 2021

Abstract
The internal flow fields of a pump/turbine interface in a torque converter were examined using laser velocimetry. The torque converter was operated at three different turbine/pump rotational speed ratios: 0.065 (near stall), 0.600, and 0.800 (near coupling point) and for each speed ratio three different pump and turbine speeds were used. Most importantly, the dimensional rotational speed had minimal effects on the flow fields — flow characteristics were Reynolds number independent. At the pump exit plane the flow is non-uniform in the blade-to-blade direction at all speed ratios and speeds. Velocities were fairly uniform in the core-to-shell direction. Through flow velocity non-uniformity became more pronounced as the speed ratio increased. The pump exit plane slip factors are near unity. At high speed ratios the flow in the turbine inlet plane flow is non-uniform in the blade-to-blade direction. Also at high speed ratios, velocities are fairly uniform in the core-to-shell direction but high velocities move near the shell at lower speed ratios. The turbine leading edge incidence angles were found to depend strongly on the speed ratio, ranging from positive to negative.
Fuzzy Logic Control of Constant Power Regulated Swash Plate Axial Piston Pumps
Authors: Kassem S. A. , Bahr M. K. 
Published: November 2021

Abstract
This paper presents a theoretical study of some aspects of the dynamics of electrically controlled constant power regulated swash plate axial piston pumps with conical cylinder blocks. The mathematical model of the pump is derived. Simulation of the pump dynamic characteristics is carried out when the controller is a conventional PD one used currently in practical applications. The good agreement between the simulation and the experimental results validates the derived model. A fuzzy logic controller (FZC) is proposed to replace the PD controller. The simulation results show that the FZC yields better dynamic performance and is more robust as compared with the PD controller. The FZC is also shown to reduce the oscillations of the proportional valve spool at each swash plate inclination angle, which increases the valve service life and reduces the generated heat in it. In case of pumps of large geometric volumes the FZC is found also to reduce the impact of the control piston at the end of the stroke.
Modelling of an Electrohydraulically-Activated Friction Damper in a Vehicle Application
Authors: Guglielmino Emanuele , Edge Kevin A. 
Published: November 2021

Abstract
This paper is concerned with the modelling and control of a servo-driven dry-friction damper employed as a part of a car suspension.
An accurate model of the hydraulic drive is developed, taking into consideration valve leakage flows. These affect closed-loop gain and hence the overall performance of the system. A robust Variable Structure Control (VSC) algorithm is proposed. The merits of different schemes are compared via numerical simulation. The vehicle ride model employed for the study has seven degrees of freedom.
Semiempirical Model for Variable Displacement Pump With Load Sensing Regulator and Power Restrictor
Authors: Käppi Timo J. 
Published: November 2021

Abstract
In this paper modeling of variable displacement pump system is discussed. The system described is typically used in mobile hydraulic applications.
An easy-to-parameterize loss model is presented which is based on the Dorey’s model. The model identification is done semi-empirically with a reduced number of parameters. Two parameters are required to identify the volumetric losses and four to determine the hydromechanical efficiency. The accuracy of the loss model is proven by comparing calculated values between the measured values of a commercial axial piston pump. The relative error in total efficiency is less than 4% over the whole range of variables and thus acceptable.
The pump system model presented includes the operation of load sensing regulator and power restrictor. The pump system model also includes the dynamic effect of a load sensing line from the mobile valve to the pump regulator and the first order dynamics of the pump itself.
The suggested model is usable in carrying out the system level simulation of mobile hydraulic machine systems. Simple examples demonstrate the application.
Relating Semiconductor Heat Sink Local and Non-Local Experimental and Simulation Data to Upper Scale Design Goals
Authors: Travkin V. S. 
Published: November 2021

Abstract
The primary difficulty in semiconductor heat sink (and many other types of heat exchangers) research and design is not a lack of interest or money, but rather confusion with what being looked for and adequacy of the tools used for the search. As recently shown, there are few meaningful parameters (apart from sizes and weight) or physical characteristics of interest in semiconductor cooler design are local values. Even the maximum temperature of the base Tmax or semiconductor temperature are not local. In this work outlined the description in detail of arguments on how, and for what reasons, the measured data are to be simulated or measured and represented in a way that allows design goals to be formulated primarily with bulk physical characteristics. We demonstrate why studies of only averaged local integrated variables are not enough. Four sample semiconductor heat sinks of two morphologies (three samples of round pin fin and one sample of longitudinal rib fin sinks) were studied by different techniques and models. There were changes in by-pass values, external heat flux and flow rate. The results are depicted with using new parameters that better represent the needs of a design process as well as the usual parameters used in the past. Characteristics reported are the heat transfer rate in solid phase, relative fin effectiveness, and influence of only morphology features among others. Some suggestions for heat sink design are discussed.
An Assessment of the Impact of Interconnect Strategies on Thermal Performance of GaAs Power Amplifier IC Devices
Authors: Adams V. H. , Lee T.-Y. Tom 
Published: November 2021

Abstract
Alternative interconnect strategies are being considered in place of the standard wire bond interconnect for GaAs power amplifier MMIC devices due to cost and electrical performance improvements. The package/die thermal performance consequences are potentially high-risk issue to these interconnect strategies and requires evaluation. Thermal simulations are conducted to compare and evaluate the thermal performances of three interconnect strategies: wire bond, gold post-flip chip, and through via interconnects. The test vehicle simulated is a three-stage, dual band power amplifier integrated circuit dissipating approximately 5 W steady-state power. Parametric studies are conducted to evaluate the impact of the printed circuit board, die thickness, solid gold vias, and design enhancements on package thermal performance.
Best thermal performance is provided by a wire bonded, thin GaAs die attached with solder die attach to a printed circuit board that maximizes the number of plated-through-holes directly under the die. This configuration results in a best case junction-to-heat sink thermal resistance of 12 °C/W. Optimum flip chip and through via designs result in degraded thermal performance compared to the above described wire bond design but may have acceptable thermal performance. For these simulations, predicted junction-to-heatsink thermal resistance is in a range of 15–20 °C/W and is better than a comparable wire bonded design that uses a conductive epoxy die attach material.
Computation of Sub-Micron Thermal Transport Using an Unstructured Finite Volume Method
Authors: Murthy J. Y. , Mathur S. R. 
Published: November 2021

Abstract
An unstructured finite volume scheme is applied to the solution of sub-micron heat conduction problems. The phonon Boltzmann transport equation (BTE) in the relaxation time approximation is considered. The similarity between the radiative transfer equation (RTE) and the BTE is exploited in developing a finite volume scheme for the BTE. The spatial domain is divided into arbitrary unstructured polyhedra, the angular domain into control angles and the frequency domain into frequency bands and conservation equations for phonon energy are written. The unsteady wave propagation term; not usually present in thermal radiation problems, is differenced using a fully implicit scheme. A sequential multigrid scheme is applied to solve the nominally linear set. Isotropic scattering due to a variety of mechanisms such as impurity and Umklapp scattering is considered. The numerical scheme is applied to a variety of sub-micron conduction problems, both unsteady and steady. Favorable comparison is found with the published literature and with exact solutions.
A Model of Bioconvection of a Dilute Suspension of Gravitactic Microorganisms in an Isotropic Porous Medium
Authors: Kuznetsov A. V. , Jiang N. 
Published: November 2021

Abstract
A new continuum model is formulated for bioconvection in a dilute suspension of swimming, gravitactic microorganisms in a porous medium. ‘Bioconvection’ is the name given to pattern-forming convective motions set up in suspensions of swimming microorganisms. ‘Gravitaxis’ describes the way of the swimming and means that microorganisms tend to swim against the gravity. The aim of this paper is to analyze collective behaviour and pattern formation in populations of swimming microorganisms. The existence and stability of a two-dimensional plume in a tall, narrow chamber with stress-free sidewalls is investigated. Governing equations include the Darcy law and the microorganism conservation equation. A conservative finite-difference scheme is used to solve these equations numerically.
Numerical Model Study of the Field of View and Temporal Response of the Infrared Sense Organ in Crotaline Pit Vipers
Authors: Pearce John A. , Schmitz Anke 
Published: November 2021

Abstract
The IR sensitive membrane of the Crotaline pit organ was modeled numerically to help interpret electrophysiologic measurements of the pit organ response to a calibrated infrared source simulating a biological target. The model results are compared to electrophysiologic measurements for an on-axis exposure (target normal to the pit organ axis, oriented for maximum response).
Additional model studies were conducted to: 1) estimate the field of view of the pit organ and 2) estimate the expected temperature rise in the membrane from the target at varying distances. The pit organ model was based on detailed measurements of its geometry. The membrane illumination irradiance difference from background thermal radiation (in W/mm2) was calculated from a quasi-analytical solution for the radiation coupling factor, Fjj. The illumination function was used to estimate temperature rise neglecting infrared heat transfer between the membrane and surrounding pit organ tissues. That is, the membrane was assumed in thermal steady state with the snake body and the environment outside of the target. The mammalian target is thus assumed to represent a small perturbation to the thermal steady state condition. This matches the electrophysiologic data, and is reasonable since the snake is cold blooded and snake body temperature is very close to its surroundings. The membrane includes blood flow effects, but it turns out that the membrane blood flow is strictly capillary in nature and changes the effective lateral thermal conductivity rather than providing significant heat transfer. The membrane is “optically thin”, being only about 5 wavelengths in thickness, and the specific optical properties of the interior layers were estimated from relative water content.