bluuebunny/crossref_metadata_2025_split huggingface dataset:
Self Heating in III-V Transistors
Authors: Anholt Robert , Dettmer R. , Bozada C. , Cerny C. A. , Desalvo G. , Ebel J. , Gillespie J. , Havasy C. , Ito C. , Jenkins T. , Pettiford C. , Liou L. , Nakano K. , Nakano K. , Quach T. , Sewell J. , Via D. 
Published: July 2023

Abstract
The III-V integrated-circuits industry makes use of measured and modeled thermal impedances to model and to optimize transistor performance and to design circuits. In field effect transistors (FETs), heat is generated in a very small volume on the drain side of the gate, but models assume that it is generated in wide rectangular bars on the surface of the device. We describe electrical techniques for measuring the thermal impedances in FETs and in heterojunction bipolar transistors (HBTs). In HBTs the maximum power densities are limited by self heating, and we describe experimental studies of thermal shunt designs that reduce the thermal impedances.
Internal Temperature Distribution of a Vertical-Cavity Surface-Emitting Lasers Measured by Scanning Thermal Microscopy
Authors: Luo K. , Herrick R. W. H. , Majumdar A. , Petroff P. 
Published: July 2023

Abstract
This paper presents the first measurements of the temperature distribution inside a vertical-cavity surface-emitting laser. The peak temperature occurred at the intersection of the optical axis and the active region and increased with laser current. The peak temperature was found to be lower, by a factor of two, than numerical predictions and previous measurements using temperature-dependent shift in the output laser wavelength. Comparison of the temperature distribution, that is responsible for thermal lensing of the output laser mode, showed that the measured axial temperature distribution deviated significantly from numerical predictions, primarily due to heat sinking on the top surface near the p mirror. The measured radial temperature distributions along the quantum wells were in very good agreement with numerical predictions.
Nanojoule Thermal Transfer in Micromechanical Heterostructures
Authors: Berger Rüdiger , Gerber Christoph , Gimzewski James K. , Meyer Ernst , Güntherodt Hans-Joachim 
Published: July 2023

Abstract
We describe recent experiments on heat-transfer processes in silicon-nitride micromechanical heterostructures using nanoscale-science techniques. The influence of various media surrounding the structures, such as ethanol, air, and vacuum, on heat loss is discussed. Key factors investigated are thermal response time and thermomechanical sensitivity. Both the effects of ohmic and laser-irradiated heating are discussed. Using a heterostructured micromechanical calorimeter, heat-transfer processes at phase transitions are determined down to the nanojoule level.
Giant Reduction in Lateral Thermal Conductivity of Thin Nitride/Silicon/Oxide Membrane Measured With a Suspended Micro Structure
Authors: Zheng X. Y. , Li S. Z. , Chen M. , Wang K. L. 
Published: July 2023

Abstract
A suspended micro structure, a thermal bridge, was developed for measurement of lateral thermal conductivity of membrane materials. Integration of several polysilicon thermal elements (heaters and temperature sensors) with a membrane in a thermal bridge makes direct and accurate measurement of lateral thermal conductivity possible. A multilayer membrane composed of a layer of silicon nitride, a layer of monocrystalline silicon and a layer of silicon oxide was tested. Two measuring methods, a small signal differential method and an equivalent circuit method, were employed for evaluation of the thermal conductivity. The two-dimensional thermal conductivity of the membrane was found to be 0.34 × 10−6 W / K. This yields a lateral thermal conductivity of less than 2.2 W / m K for the silicon layer sandwiched in the membrane. In contrast, the thermal conductivity for bulk silicon is 148 W / m K. The accuracy of the result is also discussed.
Optimum Design of Microchannel Heat Sinks
Authors: Choquette S. F. , Faghri M. , Charmchi M. , Asako Y. 
Published: July 2023

Abstract
Analyses have been performed to obtain momentum and thermal characteristics in microchannel heat sinks. The applicability of existing correlations for friction factor and Nusselt number is investigated. The study revealed that existing correlations based on the analytical results can predict the heat sink performance to within the accuracy limits acceptable for use in design. A user friendly computer code has been developed as an aid in the optimum design of microchannel heat sinks. The program, using thermal resistance models, operates in two modes. In mode one, the performance capabilities, power requirements and efficiencies of an existing heat sink design are evaluated. Mode two is used as a design tool for heat sink optimization. In this mode, given the overall heat sink geometry, fluid and substrate properties, and inlet and outlet boundary conditions, the program determines the optimum channel spacing and fin thickness. Implementation of the optimization scheme is presented and its effectiveness is evaluated. Improvements of up to 45% in heat transfer rates are observed by analyzing thermal resistance surface plots for wide ranges of fin thickness and channel spacing. In addition, the idea of designing heat sinks for turbulent conditions rather than laminar are examined. The results show that significant reductions in the total thermal resistance are not achieved by designing for turbulent flow. In contrast, significantly higher pumping power requirements are realized when designing for turbulent flow with only slight improvement in overall thermal performance.
Navier-Stokes Simulations of a Novel Micropump
Authors: Sharatchandra M. C. , Sen Mihir , Gad-el-Hak Mohamed 
Published: July 2023

Abstract
A numerical study of flow in a novel viscous-based pumping device appropriate for microscale applications is described. The device, essentially consisting of a rotating cylinder eccentrically placed in a channel, is shown to be capable of generating a net flow against an externally imposed pressure gradient. Navier-Stokes simulations at low Reynolds numbers (O[1]) are carried out using a finite-volume approach to study the influence of various geometric parameters. Slip effects for gas flows are also briefly investigated. The numerical results indicate that the generated flow rate is a maximum when the cylinder is in contact with a channel wall and that an optimum plate spacing exists. These observations are in excellent agreement, both qualitatively and quantitatively, with a previous experimental study. Furthermore, it is shown that effective pumping is obtained even for considerably higher Reynolds numbers (O[100]), thereby extending the performance envelope of the proposed device to non-microscale applications as well. Finally, slip-flow effects appear to be significant only for Knudsen numbers greater than 0.1, which is important from the point of view of microscale applications.
Control of Flow Separation Using the EMEMS Approach: Proof of Concept Experiments
Authors: Sinha Sumon K. , Pal Dipankar , Banerjee Debjyoti 
Published: July 2023

Abstract
A driven flexible wall transducer has been developed for controlling unsteady and steady separating flows. The transducer consists of an array of electrostatically active strips under a flexible surface. The transducer is at first used as a sensor to detect wall pressure fluctuation frequencies which are believed to correspond to instabilities in the attached boundary layer and the separated shear layer. Next, selected transducer strips are driven at one of the sensed frequencies so as to introduce vortices close to the wall. Reattachment can occur when these vortices move downstream to the separated shear layer. This method has been used to control transcritical flow separation on a circular cylinder (Re of 1.5 × 105) and reattach marginally separated boundary layers on an NACA 0012 airfoil at Re values slightly under 106. To increase the strength and reduce the size of the controlling vortices, an elastomeric microstructured (EMEMS) version of this transducer is presented. The EMEMS transducer also has the potential of being robust and inexpensive.
Parametric Modeling of a Microaccelerometer Using I-Optimal Design of Experiments for Finite Element Analysis
Authors: Crary Selden B. , Gianchandani Yogesh B. 
Published: July 2023

Abstract
This paper describes the characterization of a microaccelerometer using optimal design of experiments. The criteria of I- and D-optimality are used to specify a near-minimal set of 36 to 38 input points in a five dimensional input space at which finite element analysis is performed and the suitability of the optimality criteria assessed. The accelerometer is comprised of a rigid proof mass and four suspension beams. Its response is determined as a function of acceleration along the input and cross-axes, temperature, and two structural variables, and the related performance compromises are identified. In particular, it is shown that the best performance is achieved when the suspension beams are attached to the middle of each side of the proof mass.
Thin Film Shape Memory Alloy Microactuators
Authors: Krulevitch P. , Lee A. P. , Ramsey P. B. , Trevino J. , Northrup M. A. 
Published: July 2023

Abstract
Thin film shape memory alloys (SMAs) have the potential to become a primary actuating mechanism for mechanical devices with dimensions in the micron to millimeter range requiring large forces over long displacements. In this paper, the thermo-mechanical behavior of shape memory films is presented, techniques for characterizing Ni-Ti-based shape memory films are evaluated, and design issues for SMA microactuators are discussed. The substrate curvature method is used to investigate the response of Ni-Ti-Cu SMA films, revealing recoverable stresses up to 510 MPa, transformation temperatures above 32°C, and hysteresis widths between near 10°C. Fatigue data shows that for small strains, applied loads up to 350 MPa can be sustained for thousands of cycles.
Development of a Finite Element Analysis-Based Numerical Solution for Virtual Rapid Prototyping of Piezoelectric Microelectromechanical Systems
Authors: Chung Won Jee , Feng Hongwei , von Preissig Fred J. , Ghasemi Nejhad Mehrdad N. , Yuh Junku 
Published: July 2023

Abstract
The application of Finite Element Analysis (FEA) to Piezoelectric Microelectromechanical Systems (P-MEMS) is explored. Some unusual features and challenges associated with the special materials and geometries involved are discussed. FEA modeling of simple devices containing piezoelectrically active thin-film sensors and actuators is presented. Zinc oxide was the piezoelectric material used. Static electromechanical analyses were performed on two structures. The resulting deformations and voltage outputs were in excellent agreement with analytical solutions or experimental measurements. A harmonic analysis was performed on a third structure, and the resonant frequency agreed with an analytical result. The choice of ANSYS as the FEA platform for our Virtual Rapid Prototyping system for P-MEMS is shown to be a suitable one. “Top down” modeling is the preferred approach.
Microflow System and Noncontact Transportation of DNA Molecule in Microflow Channels by Dielectrophoretic Force
Authors: Morishima Keisuke , Fukuda Toshio , Arai Fumihito , Yoshikawa Kenichi 
Published: July 2023

Abstract
In this paper, we propose a new approach to noncontact transportation of DNA molecules by dielectrophoretic force and the idea of the Micro DNA Flow System. Such systems can be made by using Microfabrication technology. At first, we designed a simple micro electrode-flow system and carried out experiments. Experimental demonstration of DNA transportation using dielectrophoretic force and direct observation of the DNA molecule in a non-uniform electric field was carried out with fluorescence microscopy. We showed a simple electrode design and the possibility of noncontact transportation of DNA molecules based on Micro DNA Flow System. We consider the possibility of the Micro DNA Flow System as one of the biomanipulation and automation systems for DNA sequencing in future.
Nonlinear Dynamics of Micromachined Rate Gyros
Authors: Ljung Per B. , Pisano Albert P. 
Published: July 2023

Abstract
The full nonlinear equations of motion are derived for a general angularly driven rate gyro. Sensitivity to cross-axis angular input rates and angular input accelerations are shown in simplified form for design purposes. The gyro drive and sense axes can be operated either nonresonantly or resonantly where the natural frequencies coincide with the forcing moment. The tuning requirements and increase in coriolis sensitivity for resonant operation are detailed. Using this tuning technique, a two input axis micromachined rate gyro has been fabricated which can sense 0.15 °/sec in a 20Hz bandwidth.
Sequential Solutions of Field Equations Using a Single BEM Model
Authors: Ljung Per B. 
Published: July 2023

Abstract
A new portable CAD tool is introduced allowing a single boundary element model to solve coupled nonlinear Laplace, Poisson and Navier field equations. The compact formulation of the model and discretized differential equations allows the software to be implemented on standard personal computers. The software is implemented in vectorized Matlab code making this a portable CAD implementation. Several 2D and 3D examples are given using common micromachined structures.
Design of a Self-Closing Compliant “Mouse Trap” for Micro Assembly
Authors: Saitou Kazuhiro , Jakiela Mark J. 
Published: July 2023

Abstract
A design of a micro latching fastener — a micro “mouse trap” — is presented, which has self-closing compliant latches that clamp a free planar part inserted between them. The self-closing of the latches is induced by the insertion of the part which releases the potential energy stored in the “cocked” state of the device, in the manner of a mouse trap. The closed latch can re-open by cocking the micro mouse trap. The self-closing action of the micro mouse trap allows the inaccurate insertion of the free part and leads to very accurate final positioning, with the insertion force required to induce the self-closing being very small. The micro mouse trap is also reusable since the release of the clamped part is done nondestructively. The micro mouse trap can be used, for instance, for assembly and temporal clamping/positioning of micro-scale parts, and electromechanical/opto-mechanical connectors.
Large Deflection Effects on Micro Diaphragms: A Theoretical and Experimental Study
Authors: Lin Liwei , Chu Huey-Chi 
Published: July 2023

Abstract
Large deflection effects on piezoresistive, diaphragm type pressure sensors have been observed and analyzed. Square and circular shape diaphragms with width (diameter) of 100 μm, thickness from 1.5 to 2.0 μm, have been fabricated and tested. Linearity errors due to large deflection effect have been characterized by classical theory of plates and shells and measured experimentally. It is found that not only the thickness of the diaphragm but also the lengths of the sensing resistors affect the linearity behavior of the pressure sensors. Maximum linearity errors within 0.2% FSS (Full Scale Span) on both square and circular shape pressure sensors have been recorded and analyzed. These characteristics are useful not only in pressure sensor designs but also in building the linearity compensation circuitry for other diaphragm based precision transducers.
A Novel Technique for Penetrator Velocity Measurement in Ballistic Penetration Studies
Authors: Espinosa Horacio D. , Lu Hung-Cheng , Xu Yueping 
Published: July 2023

Abstract
A novel experimental configuration that can simultaneously record projectile velocity histories and target back surface out-of-plane motion in penetration experiments has been developed. The technique was used to investigate failure mechanisms during ballistic impact of an S-2 glass fiber woven composite with 60% fiber volume fraction. Microscopy studies performed on recovered samples clearly show interply delamination, fiber breakage, ply inelasticity, and fiber kinking as the major failure modes in these composites. Recorded penetrator velocity histories indicate the failure process is rate dependent.
Three well defined regions with different failure zones are observed in the laminate. In a region at the rear of the target plate, Region A, extensive delamination between plies is seen leading to bulge formation. Damage is observed in front of the penetrator with substantial fiber shearing. In a middle region, Region B, tensile fiber failure and large fiber deflection, to accommodate the lateral expansion generated by the steel penetrator, are observed. At the projectile entrance, Region C, fiber microfracture followed by fiber tensile failure is believed to be the failure mode in this region. Noticeable delamination is also produced in plies close to the front specimen surface. Two major fiber failures are observed in the micrographs, fiber kinking and microcracking. Well defined kink bands are seen in Regions B and C on plies with fibers oriented perpendicular to the penetration direction. The formation of kink bands appear to be the result of compressive failure due to lateral motion of the plies away from the advancing steel penetrator.
Finite Strain Analysis of Deformations of Quasibrittle Material During Missile Impact and Penetration
Authors: Bažant Zdeněk P. , Adley Mark D. , Xiang Yuyin 
Published: July 2023

Abstract
The conference presentation deals with three problems involved in finite element analysis of the impact of missiles into reinforced concrete walls and their penetration through the walls: (1) Formulation of the constitutive law for complex nonlinear triaxial behavior of concrete, including the strain-softening damage; (2) extension of the formulation to very large finite strains; and (3) application of the model in dynamic finite element analysis. Only problem (2) is discussed in some detail in this brief paper. Because the Biot strain tensor has a clear physical meaning even for very large finite strains, its use is preferable in the fitting of complex triaxial test data. It is shown that the constitutive relation can be conveniently formulated as a relation of the Biot strain tensor to the back-rotated Cauchy stress tensor, and the justification of this form of the constitutive relation is given.
Extrusion of Low-Density Microcellular HIPS Foams Using CO2
Authors: Behravesh Amir H. , Park Chul B. , Venter Ronald D. 
Published: July 2023

Abstract
A continuous extrusion process for the manufacture of low-density microcellular polymer is presented. Microcellular polymers are foamed plastics characterized by a cell density greater than 109 cells/cm3 and a fully grown cell size on the order of 10 μm. The basic approach to the production of microcellular structures is to continuously form a polymer/gas solution, nucleate a large number of bubbles using rapid pressure drop, shape a nucleated polymer/gas solution under pressure, and induce a volume expansion to a desired expansion ratio. Successful completion of these steps in extrusion will enable the manufacture of microcellular foamed plastics with a high cell-population density.
Previous research on the continuous processing of microcellular polymers has focused on control of microcell nucleation in extrusion. This paper presents an effective means for the control of cell growth to achieve a desired expansion ratio with CO2 as a blowing agent in microcellular foam processing. Also, a strategy to prevent the deterioration of the cell-population density via cell coalescence during expansion is presented. The promotion of a desired volume expansion ratio and the prevention of the cell coalescence in microcellular foam processing were experimentally verified. By tailoring the extrusion processing parameters, microcellular HIPS foams with a cell density of 1010 cells/cm3 and a controlled expansion ratio in the range of 1.5 to 23 were obtained.
Net-Shape Forming of Sintered Microcellular Foam Parts
Authors: Seeler Karl A. , Billington Scott A. , Drake Bruce D. , Kumar Vipin 
Published: July 2023

Abstract
The time required to saturate a polymer with gas increases with the square of the diffusion length. This has effectively limited the application of the batch process of producing microcellular foam to thin parts. Saturating powdered polymer rather than solid polymer and then sintering the particles to create a net-shape microcellular part is an alternative technique. The advantage of sintering microcellular parts from saturated polymer powder is the great reduction in the diffusion length reduces saturation time from days to minutes. Saturation time is decoupled from part thickness.
A prototype has been designed and tested in which saturated polymer powder is blown into a mold under the pressure of the saturating gas. The absorbed gas plasticizes the polymer. The powder is compressed into a solid preform to remove macroscopic voids, increase the diffusion distance to slow gas desorption, and to increase thermal conductivity. The preform is then heated, the mold expanded, and microcellular part formed to net shape in a closed mold. Preliminary tests with polycarbonate, amorphous polyethylene terephtalate (PET-G), and cellulose acetate have been successful.
Longitudinal Development of Physical Characteristics and Function in Japanese Junior Rugby Union Players
Authors: Kumazaki Akira , Fujimoto Tomomi , Matsuura Yuiko 
Published: July 2023

Purpose: To longitudinally investigate the development of physical characteristics and function during 3 years of high school among Japanese junior rugby players and examine the differences in these parameters between the positions. Methods: In 83 junior rugby players (forwards: n = 46, backs: n = 37) from one Japanese high school team who had participated in national high school competitions, anthropometric variables (height, body mass, fat and lean body mass, and body mass index), upper- and lower-body strength (eg, 1-repetition-maximum [1RM] bench press, isokinetic knee muscle strength at 60°/s and 180°/s), and sprint and jump performance were measured. Upper- and lower-body strength relative to body mass and lean body mass were also calculated. Results: All anthropometric indices improved with increasing age, and the values were higher in forwards than in backs (all P < .05). The 1-repetition maximum bench press (forwards: 40.8%, backs: 52.5%) and isokinetic knee strength (eg, extension at 60°/s, forwards: 15.4%, backs: 10.0%) improved with age (from 16 to 18 y), and they were higher in forwards than in backs (all P < .05). Meanwhile, the 1RM bench press relative to lean body mass did not differ between the positions. Isokinetic knee muscle strength at 60°/s and 180°/s relative to lean body mass and sprint and jump performance did not improve with age. Conclusion: These results indicate that Japanese junior rugby players need to develop larger physiques and continuously increase their lower-body strength to improve sprint and jump performance.
Draft genome sequences of two strains of
Staphylococcus aureus
isolated from mastitis-infected camel in Kajiado County, Kenya
Authors: Mwangi Kamau , Gachogo Rachael , Masila Ednah , Ogali Irene , Langat Nathan , Onywera Ruth , Malonza Vincent , Wesonga Hezron , Maichomo Monicah , Murungi Edwin 
Published: July 2023

ABSTRACT

We report the draft genome sequences of two
Staphylococcus aureus
strains isolated from a mastitis-infected camel in Kajiado County, Kenya. The 2,739,512-bp and 3,025,943-bp draft genomes coding for 2,577 and 2,889 protein sequences, respectively, provide invaluable data for the computational design of a camel mastitis subunit vaccine.