bluuebunny/crossref_metadata_2025_split huggingface dataset:
Design and Utilization of Virtual Machines and Processes
Authors: Bzymek Zbigniew M. 
Published: December 2021

Abstract
Virtual Models (VMd), Virtual Machines (VMn) and Virtual Processes (VP) are becoming more and more useful tools in manufacturing design, research and development of products. They give possibility to investigate manufacturing and production problems prior to building a physical model or prototype of the machine. Virtual Machines and Virtual Processes are technologies used in the design of machining equipment and in looking at production processes. They consist of a group of recently developed techniques and approaches that allow the construction of machine computer models and the simulation of the fabrication process. What makes this group of manufacturing technologies special is that they allow the checking of machining and production parameters before actual prototypes and their specific tooling are manufactured. The possibility of using these virtual manufacturing techniques could result in great savings of both time and money. In general, virtual manufacturing promises shorter design cycles with more design iterations, leading to an optimal design and better use of resources. The end goal of any virtual manufacturing is to produce a virtual model of a machine that will virtually make the part from its database file containing the geometrical description of a physical object in terms of pre-defined geometric entities. The actual manufacturing hardware provides the physical means to machine the part, which Virtual Machining allows making the as a computer model. Special software is employed to bridge the gap between the CAD data and the virtual manufacturing system. Such software should control various parameters such as the rate at which the positioning system proceeds, the tool path, the thickness of the layer of the material for removal and/or length of the path, the slice length, and others. Virtual manufacturing provides a means of motion control and easy manipulation of various manufacturing hardware.
The methods and software described in this paper allow the creation of different kinds of milling and grinding machines which are later compared with the actual existing machines and the parts produced by them. Three virtual systems are presented in this paper. One system was compared to the actual system operating in the CAD&CAM and Expert Systems Laboratory, and another was designed for stereoscopic view experiment. The third is a new machine that is in the design process. Also some examples of workpiece finish produced by virtual machining are described.
The work presents an effort to extend virtual manufacturing techniques in design, testing demonstration and manufacturing equipment and processes as well as the teaching of design and manufacturing. The work was conducted at the University of Connecticut using Silicon Graphics systems equipped with inventor, GL library and C compilers.
Hybrid Least Squares Finite Element Methods for Reissner-Mindlin Plates
Authors: Thompson Lonny L. , Tong Yuhuan 
Published: December 2021

Abstract
An assumed-stress hybrid 4-node plate element is developed based on the Hellinger-Reissner variational principle modified with a generalized least-squares operator for accurate vibration and wave propagation response of Reissner-Mindlin plates. The least-squares operator is proportional to a weighted integral of a differential operator acting on the residual of the steady-state equations of motion for Reissner-Mindlin plates. Through judicious selection of the design parameters inherent in the least-squares modification, this formulation provides a consistent framework for enhancing the accuracy of mixed Reissner-Mindlin plate elements that have no shear locking or spurious modes. Improved methods are designed such that the complex wave-number finite element dispersion relations closely match the analytical relations for all wave angle directions. For uniform meshes, optimal methods are designed to achieve zero dispersion error along given wave directions. Comparisons of finite element dispersion relations demonstrate the superiority of the new hybrid least-squares plate element over the underlying hybrid element, and standard Galerkin elements based on selectively reduced integration. Numerical experiments validate these conclusions.
Correlation Between Register Pressure Drop and Noise
Authors: Humbad Niranjan G. , Chudzinski Andy 
Published: December 2021

Abstract
During the register design for automotive applications, airflow pressure drop and noise generation have to be considered. Testing different register design concepts for flow and noise can not be easily performed in the vehicles. Therefore, a simple measurement method was devised to evaluate the register as a component for flow and noise. The register to be evaluated was mounted on one face of a 35 × 35 × 35 cm box and flow was provided from the opposite face of the box. Pressure drop was measured in the box at various airflow rates. Noise measurements were carried out in semi-anechoic room. The noise and flow measurement data on 9 registers showed a large spread in flow pressure drops and noise levels at a given airflow (suggesting a large variation in register to register designs). The measured data is compared with theory to predict A-weighted sound pressure levels. This prediction model can be used in predicting sound pressure levels from measured or calculated flow pressure drop values.
Visualization of Sound Radiation From a Bowling Ball
Authors: Leach Kesho , Wu Sean F. 
Published: December 2021

Abstract
This paper presents results of an investigation on visualization of sound radiation from a bowling ball via the Helmholtz Equation Least Squares (HELS) method [Wang and Wu, 1997; Wu and Wang, 1998; Wu and Yu, 1998]. In conducting the tests, the bowling ball was excited by a vibration shaker using a random signal. The radiated acoustic pressures were measured over both conformal and planer surfaces at certain distances away from the source. The measured data were taken as the input to a computer model based on the HELS formulation. The reconstructed acoustic pressures on the surface and in the field were compared with the measured data at the same locations. Also shown are comparisons of the reconstructed and measured acoustic pressure spectra at various locations on the bowling ball surface. Results demonstrate that the accuracy of reconstruction based on measurements over a conformal surface is much higher than that over a planar surface. This is because a planar surface often extends beyond the near-field region, thus making the accuracy of measurements inconsistent. Nevertheless, satisfactory visualization of acoustic pressure distribution over the entire bowling ball surface can still be obtained, at least in the low-to-mid frequency regime, based on the measurements over a finite, planar surface on one side of the source. Such a capability is unique to the HELS method. However, the efficiency of numerical computations of the HELS method is expected to deteriorate at high frequencies, a difficulty inherent in all expansion theories.
Combined Transducer and Nonlinear Tissue Propagation Simulations
Authors: Wojcik Gregory L. , Mould John C. , Carcione Laura M. 
Published: December 2021

Abstract
Ultrasonic imaging system evaluation is often based on models of the transducer as a distribution of baffled piston sources, and of the tissue as a homogeneous, linear acoustic medium, e.g., Jensen’s Field code. In reality, these are fairly gross idealizations, since the transducer exhibits more complicated response modes and real tissue is inhomogeneous and nonlinear. Greater model fidelity would be useful, especially in the context of transducer design qualification, second harmonic imaging, and acoustic power indices. To this end we combine 2D finite element models of transducer dynamics with highly accurate 2D finite difference propagation models in the large-scale inhomogeneous tissue cross-sections. Transducer models employ the time-domain code, PZFlex, and tissue models utilize a new pseudospectral solver to be included in PZFlex. The pseudospectral algorithm solves the inhomogeneous acoustic wave equation using FFTs for high order approximation of the spatial differential operator and a fourth-order, explicit time integrator. Second-order (B/A) nonlinearity and frequency-accurate, causal absorption are included. We describe the algorithmic and modeling issues, and present a suite of simulations in lossy, nonlinear abdominal cross sections and tissue showing coupling of the 1D medical array to the tissue model and scattering from deeper inhomogeneities and back to the transducer. In contrast to paraxial schemes, like the KZK method, details of the field transmitted from the transducer and all backscatter within the model are included. However, models are currently limited to 2D (plane or axisymmetric) on readily available hardware.
Edge Flutter
Authors: Chang Young B. , Cho Chang H. , Moretti Peter M. 
Published: December 2021

Abstract
During manufacturing processes of thin materials (called webs) such as papers, photographic films, and magnetic films, the free edges of a web can vibrate violently due to the airflow in the cross direction. A traveling-wave analysis was done based on linear potential flow theory, and the critical flow velocity, wave velocity, wavelength and flutter frequency were predicted. Experimental verification was done in a wind tunnel built around a web-translating machine. Two laser-Doppler vibrometers were used for non-contact measurement of wave characteristics. For flexible webs, the theory and test results show good agreement. Test results for stiff webs, however, deviate from the prediction.
Force Distribution Dependence of Sound Radiation From a Doubly Rib-Stiffened Plate
Authors: Feit David , DiPerna Daniel 
Published: December 2021

Abstract
Analytical formulae for both the velocity spectrum and the acoustic far-field radiated sound pressure for a doubly rib-stiffened (small frames and bulkheads) fluid-loaded elastic plate, excited by several different force distributions, are derived. The force distributions are (1) a line-force applied at a single point and (2) two Gaussian distributed force intensities whose effective width either spans the small rib spacing or the large rib spacing. The far-field sound pressure as a function of frequency is calculated. The concentrated line force case shows evidence of frame interference effects (sometimes referred to as Bloch waves) in the radiated pressure fields. These arise from coherent interaction of the pressure fields emanating from the frame reaction forces and the applied force pressure field. The frequencies at which these coherence effects are manifest depend on the stiffeners’ spacing as compared to the fluid-loaded flexural wavelength. The Gaussian force distribution eliminates these interaction effects depending on whether or not the effective force width is greater or less than the respective rib spacing.
Micro-Stereolithography of 3D Complex Ceramic Microstructures and PZT Thick Films on Si Substrate
Authors: Jiang X. N. , Sun C. , Zhang X. 
Published: December 2021

Abstract
Microstereolithography of ceramics is investigated in this paper. Ceramic line width and lateral dimension control experiments are carried out and on the basis of these, three-dimensional alumina microstructures and PZT thick films on Si substrate are fabricated and characterized. A minimum line width of 5.7 μm (with the layer thickness of 10 μm) has been achieved. Three-dimensional ceramic microstructures with feature sizes ranging from 50 μm to 1mm are fabricated from alumina suspensions (50%∼59.5% Vol.). PZT thick films (50∼130 μm thick) have been successfully patterned on silicon substrate. The piezoelectric coefficients of the fabricated PZT thick films are measured as d33 of 100 pC/N and g33 of 59.5 × 10−3 Vm/N, which are more promising for applications compared with those of PZT films fabricated by other methods.
PIV Analysis of Instantaneous Flow Structures in an Inkjet Printhead
Authors: Zhang Hongsheng , Meinhart Carl D. 
Published: December 2021

Abstract
This paper presents experimental measurements and observations of instantaneous flow structures inside an inkjet printhead, using a micron-resolution Particle Image Velocimetry (PIV) system to record visualized flows and calculate velocity fields. The PIV technique uses 700 nm diameter fluorescent flow-tracing particles, a pulsed Nd:YAG laser, an epi-fluorescent microscope and an interline-transfer CCD camera to record images of a flow at two successive instances in time. By measuring how far a set of particles move during a specified duration of time, an estimate of the local fluid velocity can be obtained.
An electronic timing strategy has been developed to synchronize the PIV lasers, the CCD camera and the drop ejection system. An overall flow pattern during a 500 μs ejection cycle has been observed by phase-averaging hundreds of instantaneous velocity fields, which were recorded at 2–5 μs intervals throughout the cycle. A velocity field with spatial resolution of approximately 10 μm was obtained near the inkjet nozzle. Meniscus and nodes inside the printhead were also observed and recorded.
Design, Fabrication and Characterization of Micromirror Array for Display Application
Authors: Shin H. , Ko H. , Yoon Y. , Choi B. 
Published: December 2021

Abstract
A new design of micromachined mirror array for display purpose from Samsung Electronics is presented. Integrating multiple functions into a component and extensive use of photolithography make this design of mirror to be simple as well as easy to make.
The prototype is fabricated in an array of 50 × 50 micromirrors. The size of mirror plate is 50 × 50μm2 and the gap between them is 3μm. The mirror plate is tilted by the electrostatic force, and the angle is designed to be 10°.
Driving voltage for the finished micromirrors is 28v and the tilt angle is measured as 8.9°. The response time from the rest to full tilt and back to rest position takes about 20μs when it is driven at the natural frequency of 24.7kHz.
In the reliability point of view, the importance of anti-stiction coating can not be over stressed. Without one, most of the mirrors couldn’t survive a few contacts with the substrate. However, when proper anti-stiction coating is applied and atmosphere is controlled to eliminate the humidity, 94.6% of micromirrors were still rocking after 1.15 × 1010 cycles.
In a series of experiments, it was possible to show this new design of micromirror array could be used as a display device, when they are driven at a certain combination of addressing and bias signals. A variable character generation and PWM-type brightness control is successfully demonstrated.
An Electrochemically Actuated Micro Dosing System With Improved Dosing Control
Authors: Böhm Sebastian , Olthuis Wouter , Bergveld Piet 
Published: December 2021

Abstract
In this contribution a micromachined electrochemically-actuated micro dosing system is presented, which accurately can manipulate fluids in microsystems in the nanoliter range. The driving force to actively dispense liquids is provided by the electrochemical generation of gas bubbles (hydrogen and oxygen) by the electrolysis of an electrolyte. As these bubbles expand, they indirectly drive liquid out of a liquid filled reservoir, which is in hydraulic contact with the electrolyte in the bubble reservoir. The dosing system consists basically of a micromachined channel/reservoir structure in silicon, realized by dry reactive ion etching (DRIE). On top of this silicon fluidic board, a Pyrex® cover is bonded on which a set of electrodes is structured. These electrodes are applied for the generation of gas bubbles and at the same time, to measure the impedance of the gas/electrolyte mixture that is formed after bubble generation. It will be shown that this measured impedance reflects the gas bubble fraction in the bubble reservoir and that this parameter can be applied in determining the dosed amount of fluid. Besides the integrated sensor/actuator electrodes, measures have been taken to reduce the catalytic back reaction from the hydrogen oxygen gas mixture to water, as have been observed in the past.
Fabrication of a Free Floating Silicon Gate Valve
Authors: Papavasiliou Alexandros P. , Liepmann Dorian , Pisano Albert P. 
Published: December 2021

Abstract
This paper introduces an active planar microvalve with free floating moving pieces and a novel process for fabricating that valve. The valve presented has all of its moving pieces and actuation in the plane of the wafer in which it is microfabricated. The valve can be moved up to 100 μm using thermally generated vapor bubbles to provide actuation. The fabrication process involves bonding a thin (∼100μm) wafer to a handle wafer with epoxy. The moving pieces are then defined with DRIE etching and released from the epoxy bond with an oxygen plasma. The theoretical performance of the valve is presented as well as experimental results.
DSMC Simulation of Microfilter Elements
Authors: Aktas Ozgur , Aluru N. R. , Ravaioli Umberto 
Published: December 2021

Abstract
Direct Simulation Monte Carlo (DSMC) analysis of micro-filter elements for collection of airborne particles is considered in this paper. Three filter elements with different dimensions were simulated. Boundary conditions were chosen to simulate an array of filters. Our results indicate that, as the filter gets smaller, the slip flow will be critical in determining flow characteristics. The change in the flow rate and the characteristics of the flow in different dimensions are investigated.
Modeling and Prediction of Sub-Micrometer Heat Transfer During Thermomechanical Data Storage
Authors: King William P. , Santiago Juan G. , Kenny Thomas W. , Goodson Kenneth E. 
Published: December 2021

Abstract
Heat transfer governs the bit size and writing rate during sub-micrometer thermomechanical data storage with Atomic Force Microscope (AFM) cantilevers. The present work predicts the temperature distribution and rates of heat flow in the AFM tip and the substrate as functions of the peak cantilever temperature, the diameter of the tip-substrate contact, and the thickness of the deforming polymer coating on the silicon substrate. The calculations consider increased phonon scattering, radiation losses, and gas conduction losses at the silicon tip boundaries. Nearly ballistic phonon transport in the tip augments the dependence of the heat rate into the polymer on the tip-polymer contact diameter. For a cantilever heater temperature of 700 K and a polymer layer thickness of 80 nm, the temperature at the tip-polymer interface is predicted for contact diameters from 4 nm to 50 nm. This work models the deformation of the polymer layer during data writing and predicts data bit size as a function of tip temperature and writing time. These simulations will help optimize the design of the cantilever and the polymer data layer, with the goal of increasing the spatial density and rate of bit formation.
Global Approximation: Performance Comparison of Different Methods, With an Application to Road Vehicle System Engineering
Authors: Gobbi Massimiliano , Mastinu Giampiero 
Published: December 2021

Abstract
Optimisation of complex mechanical systems has often to be performed by resorting to global approximation. In usual global approximation practice, the original mathematical model is substituted by another mathematical model which gives approximately the same relationships between design variables and performance indexes. This is made to ensure much faster simulations which are of crucial importance to find optimal solutions. In this paper the performances of four global approximation methods (Neural Networks, Kriging, Quadratic Approximation, Linear Interpolation) are compared, with reference to an actual optimal design problem. The performances of a road vehicle suspension system are optimised by varying the system’s design variables. The Pareto-optimal set is derived symbolically. The performances of the different approximation methods taken into consideration are assessed by comparing the numerical- and the analytical-Pareto-optimal results. It is found that Neural Networks obtain the best accuracy.
Virtual Reality Assisted Visual Feedback of Cervical Spine Kinematics for Improved Control of Active Range-of-Motion Maneuvers
Authors: Sakai Jonathan L. , Gilbertson Lars G. , DeFrate Louis E. , Donaldson William F. , Kang James D. , Woo Savio L.-Y. 
Published: December 2021

Abstract
The current study investigated the efficacy of virtual reality (VR) assisted visual feedback for improving control of voluntary movements of the cervical spine during performance of active range-of-motion maneuvers. Active range-of-motion was assessed in 10 asymptomatic volunteers, both without and with VR-assisted visual feedback of overall cervical spine rotations. 8 of the 12 secondary rotations were significantly lower (p &lt; 0.01) with VR feedback than the corresponding secondary rotations without VR feedback. No statistically significant differences were found between the primary rotations attained without VR and with VR feedback. These results support the use of VR-based visual feedback for enabling control of in-vivo cervical spine kinematics.
PIV Measurements of Flow Distal to Polyurethane Heart Valve Prosthesis Under Steady and Pulsatile Flow Conditions
Authors: Kim Jung Kyung , Sung Jaeyong , Yoo Jung Yul , Chang Jun Keun , Min Byoung Goo 
Published: December 2021

Abstract
Hemodynamic performance of a polyurethane heart valve prosthesis was evaluated in comparison with that of Björk-Shiley Monostrut mechanical valve in steady and pulsatile flow. Pressure losses through the valves were obtained from the streamwise pressure distributions downstream of the valves under steady flow condition. Unsteady and turbulent flow through the heart valve prostheses were investigated using PIV in conjunction with the opening behaviors of valve leaflets. Direct measurements of the wall shear stress by hot-film anemometry (HFA) were compared with the PIV data. By examining the velocity field downstream of the polyurethane heart valve, it is known that high shear stress regions exist at the interface between strong axial jet flows along the wall and vortical flows in the central area. In addition, there are large recirculation regions near the valve, where thrombus formation can be induced by accumulation of damaged blood cells. A correlation between the flow pattern downstream of the valve and the corresponding opening posture of the polyurethane valve leaflet gives useful data necessary for improved design of the superstructure and leaflet geometry of the valve.
Advances in 3-D Vascular Ultrasound Imaging
Authors: Fenster Aaron 
Published: December 2021

Abstract
In spite of the progress in the understanding of atherosclerotic disease made in the past two decades, neither the triggering mechanisms for carotid plaque haemorrhage and disruption, or the importance of plaque ulceration are well understood. Controversies exist because the mechanisms are complex and agreement on definitions (e.g., ulceration) is lacking. Advances in imaging techniques are helping to diagnose and quantify plaque morphology, composition, extent and ulceration (Steifler et al. 1994). In this paper we report on our work focusing on the development of improved non-invasive imaging tools, which will improve the accuracy and reduce the variability of the carotid exam and allow better serial monitoring. These will help elucidate the mechanisms contributing to the last phase of atherosclerosis — plaque disruption and haemorrhage.