bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reduced Models for Computational Structural Acoustics in the Medium-Frequency Range
Authors: Soize Christian 
Published: December 2021

Abstract
This paper deals with a method in computational structural acoustics adapted for constructing reduced models in the medium-frequency range to a general three-dimensional dissipative structure consisting of an anisotropic, inhomogeneous, viscoelastic bounded medium coupled with an internal acoustic cavity. The reduced models are obtained using the Ritz-Galerkin method for which the projection subspace corresponds to the dominant eigensubspace of the energy operator of the structure in the medium-frequency band of analysis. A basic example is presented to validate the method, for which the structure and the internal acoustic cavity have a medium-frequency behavior in the frequency band of analysis.
Finite Element Formulation of Exact Dirichlet-to-Neumann Radiation Conditions on Elliptic and Spheroidal Boundaries
Authors: Thompson Lonny L. , Huan Runnong , Ianculescu Cristian 
Published: December 2021

Abstract
Exact Dirichlet-to-Neumann (DtN) radiation boundary conditions are derived in elliptic and spheroidal coordinates and formulated in a finite element method for the Helmholtz equation in unbounded domains. The DtN map matches the first N wave harmonics exactly at the artificial boundary. The use of elliptic and spheroidal boundaries enables the efficient solution of scattering from elongated objects in two- and three-dimensions respectively. Modified DtN conditions based on first and second order local boundary operators are also derived in elliptic and spheroidal coordinates, in a form suitable for finite element implementation. The modified DtN conditions are more accurate than the DtN boundary condition, yet require no extra memory and little extra cost. Direct implementation involves non-local spatial integrals leading to a dense, fully populated submatrix. A matrix-free interpretation of the non-local DtN map for elliptic and spheroidal boundaries, suitable for iterative solution of the resulting complex-symmetric system is described. For both the DtN and modified DtN conditions, we describe efficient and effective SSOR preconditioners with Eisenstat’s trick based on the matrix partition associated with the interior mesh and local boundary operator. Numerical examples of scattering from elliptic and spheroidal boundaries are computed to demonstrate the efficiency and accuracy of the boundary treatments for elongated structures.
Nonlinear Deformation of Multilayer MEMS Structures
Authors: Dunn Martin L. , Zhang Yanhang , Roy Jeffrey M. , Labossiere Paul E. W. , Bright Victor M. 
Published: December 2021

Abstract
We studied the deformation behavior of polysilicon/gold plate structures used for microelectromechanical systems (MEMS). We designed and had fabricated (using the MUMPS foundry process at Cronos Integrated Microsystems, Inc.) a series of test structures each consisting of a square polysilicon plate partially covered with gold films of different sizes and shapes. Deformed shapes of the polysilicon/gold plates were measured at room temperature using an interferometric microscope. For relatively small gold pads, the deformations were consistent with intuition and with predictions from a linear analysis; they deformed symmetrically, with roughly spherical curvature. With increasing gold pad size, though, the plates displayed nonsymmetrical deformations with roughly cylindrical curvature. A linear analysis was insufficient to explain this result, but a nonlinear one did, indicating a bifurcation due to the development of large deformations. We discuss this interesting, and potentially useful, physical phenomena and compare measured and predicted results.
Tension Test With Single-Crystalline-Silicon Microspecimen
Authors: Yi Taechung , Kim Chang-Jin “CJ” 
Published: December 2021

Abstract
Young’s moduli of single crystalline silicon in three major directions are measured by direct uniaxial tension tests using a microscale beam specimen. The 10 μm thick, 50 to 100 μm wide and 6 mm long tension specimens are micromachined along the three major crystal directions from two different types of silicon-on-insulator (SOI) wafers, (100) top layer and (110) top layer. A uniaxial tension loading frame is custom-built for the testing. Stress and strain are measured using a commercial load cell and a laser interferometry system, respectively. Measured Young’s moduli in 〈100〉, 〈110〉, and 〈111〉 directions are 115.3, 169.2, and 191.1 GPa, respectively. Expected to be insensitive to the sample size or fabrication method, Young’s moduli of single crystalline silicon can be a good measure of the reliability of microspecimen tension test systems.
Residual Stress and Thickness Control of Piezoelectric Multilayer Micromirror Actuators for Initial Deflection Minimization
Authors: Kim Myeong-Jin , Cho Young-Ho 
Published: December 2021

Abstract
We present the design, fabrication and characterization of multi-layer piezoelectric micromirror actuators for minimizing the initial deflection without loosing the actuation performance. We modified the initial designs in order to minimize the initial deflection of the multi-layer device by changing the residual stress and thickness ratio of selected layers, thereby reducing the residual stress gradient across the multi-layered thin film materials. The modified designs are fabricated by surface-micromachining process. Experimental results indicate that over 70% reduction of the initial deflection has been achieved by the residual stress and thickness control of the multi-layer piezoelectric micromirror devices.
Meso-Scale Electromagnetic Actuators Fabricated in Low-Temperature Co-Fired Ceramic Tapes
Authors: Kim Moon , Kim Dennis , Ananthasuresh G. K. , Bau Haim H. 
Published: December 2021

Abstract
Meso-scale electromagnetic actuators in low-temperature co-fired ceramic (LTCC) tapes were fabricated, tested, and analyzed. Two types of designs were considered: a NdFeB permanent magnet bonded to Kapton (polyimide film material from Du Pont) beam and a permalloy (soft magnetic material) beam. In both cases, electromagnetic coils printed on ceramic tapes were used for actuation. The beam deflection was measured as a function of applied current. In the case of the permanent magnet actuator, the experimental observations were compared with theoretical predictions.
Linear Thermomechanical Microactuators
Authors: Cragun Rebecca , Howell Larry L. 
Published: December 2021

Abstract
Thermomechanical in-plane microactuators (TIMs) have been designed, modeled, fabricated, and tested. TIMs offer an alternative to arrays of smaller thermal actuators to obtain high output forces. The design is easily modified to obtain the desired output force or deflection for specific applications. The operational principle is based on the symmetrical thermal expansion of variable cross sections of the surface micromachined microdevice. Sixteen configurations of TIMs were fabricated of polysilicon. Finite element analysis models were used to predict the deflection and output force for the actuators. Experimental results were also recorded for all sixteen configurations, including deflections and output forces up to 20 micron and 35 dyne.
Integrated LTCC Coils for Multiple Applications in Meso-Electro-Mechanical Systems
Authors: Gongora-Rubio Mario , Santiago-Aviles Jorge J. , Sola-Laguna Luis , Smith Michael 
Published: December 2021

Abstract
Often the designer of small electro-mechanical systems is willing to sacrifice small size and power consumption for the sake of low cost, ease of processing and enhanced yield.
We have been working on the utilization of Low Temperature Co-fired Ceramic tapes (LTCC) for the implementation of intermediate scale (meso-scale) devices with the simultaneously or secondary task of micro-electronic packaging.
We have designed and implemented several sensors and actuators having in common the utilization of electro-magnetic forces and interactions as the fundamental working mechanism.
For this purpose we have designed and constructed a series of coils utilizing LTCC tapes suitable for multiple sensing and actuating tasks.
As sensors, we have implemented a proximity sensor and a non-contact displacement sensor and a differential pressure sensor with a ferrofluidic core.
As actuators we have implemented a normally closed valve and a Joule effect heater.
Integrated Mixing/Reaction Micro Flow Cell for Chemical and Biochemical Applications
Authors: Nakamura Ryosuke , Shoji Shuichi , Yotsumoto Akira 
Published: December 2021

Abstract
An integrated mixing/reaction micro flow cell which consists of a sample/reagent mixing channel, a visible port and a reaction chamber was designed, fabricated and tested. A micro cone hole array of macro porous Si was employed for reagent injection part. A visible light transparent PDMS slab was used as the visible port. A Ti-Pt thin film heater and a p-n junction diode temperature sensor were integrated on the reaction chamber to realize feedback temperature control. Uniform mixing and precise temperature control were realized by the fabricated micro flow cell. The striate and simple microchannel structure of the micro flow cell is suitable for multiplexed micro reactor for chemical and biochemical applications.
A Novel Fabrication Methodology for Micromachined Sensor-Arrays With Multi-Thickness Configuration
Authors: Li Xinxin , Lin Rongming , Bao Minhang 
Published: December 2021

Abstract
A novel fabrication technology is presented for bulk micro-machining of mechanical sensor-arrays, which are constructed on the scheme of different structure unit with different structural thickness for different mechanical sensitivity. Using the novel fabrication methodology, different sensing-elements of different thickness can be integrated formed. The fabrication is based on a masked-maskless two-stage anisotropic etching technology. By designing for the pattern of a layer of mask and controlling for the etching depth, several micromachined sensor-array structures have been successfully formed, such as diaphragm-array for pressure sensing-array and beam-mass array for acceleration switch, etc. The description is focused on etching principles for the multi-thickness structures, mask design and experimental results. The novel technique is quite suitable for mechanical sensor-arrays or switch-arrays structures, as lots of sensing elements with various mechanical sensitivities can be integrated fabricated by using the easy controlled etching technology. Besides, the scheme of varying thickness saves the in-plane area occupation of each structure-unit and, thus, contributes to high integration density of the array structure.
Capillary Forces at the Interface of a MEMS Actuator
Authors: Sager Chad , Saif Taher 
Published: December 2021

Abstract
A MEMS actuator has been designed, fabricated, and tested for the purpose of understanding capillary forces of liquids at the microscale. Experiments showed that this novel design method allows a MEMS plate, with dimensions of 100 μm × 20 μm × 4 μm thick, to be lowered by 10× its thickness into de-ionized water without inundation of the plate or the MEMS actuator’s sensitive areas. The maximum force applied to the MEMS actuator during the lowering of the device was 5.2 μN, as recorded by the calibrated MEMS springs. In another experiment, the plate was extracted from the water’s surface and a maximum force of 12.3 μN was applied to the plate. Movement of the plate during extraction was 40–50 μm. The novel design method utilizes the ability of sharp edges to prohibit the spreading of the de-ionized water. The mechanism by which the contact line between the water, air, and MEMS plate moves is described in detail. This mechanism also explains why the maximum force during the lowering of the plate was less than that of the plate being extracted from the water’s surface.
PIV Measurement of Electro-Osmotic and Pressure-Driven Flow Components in Microfluidic Systems
Authors: Cummings Eric B. 
Published: December 2021

Abstract
Methodology and analysis software have been developed that produce high-spatial-resolution field measurements of depthwise uniform, linear shear, and parabolic components of the velocity from particle-image videos in which the depthwise direction is not resolved. These velocity components can be approximately identified with uniform electrokinetic flow, electrokinetic flow with a ζ-potential difference between the bottom and top surfaces, and pressure-driven flow, respectively. This software has extracted measurements of the uniform and parabolic components of mixed pressure-driven and electrokinetic particle flows over heterogeneous boundaries. This decomposition of flow components simplifies the interpretation of complicated microflows.
Theory and Modeling of Continuous Electrowetting Microactuation
Authors: Lee Junghoon , Kim Chang-Jin “CJ” 
Published: December 2021

Abstract
This paper investigates theoretical aspects of microactuation by continuous electrowetting (CEW), actuation based on electrical control of surface tension. Known as a powerful actuation mechanism in microscale for some time, compatibility of CEW with lithographic fabrication technologies of MEMS has been demonstrated recently. This paper describes theoretical interpretation and modeling of the motion by CEW, explaining the experimental observation. We considered several electrochemical and fluid mechanical effects important for further microfluidic applications. These include details of fluid motion, modeling for different modes of motion, and the effect of fluid resistance in the micro channel.
Fuel Injection by a Thermal Microinjector
Authors: Lee Yi-Kuen , Yi Ui-Chong , Tseng Fan-Gang , Kim Chang-Jin “CJ” , Ho Chih-Ming 
Published: December 2021

Abstract
This paper reports a new application of a thermal microinjector for fuel injection. The paper estimates the ejected velocity of the diesel fuel droplet, and the minimum temperature for bubble formation. The fuel spray penetration is calculated by solving nonlinear equations of motion. Analysis of the temperature profile evolution and activation curve between water and diesel fuel is helpful for optimization of the microinjector design. The microinjector is fabricated using combined surface and bulk micromaching. The preliminary testing of the microinjector with fuel demonstrates the possibility of droplet ejection. Also, discussion about design issues reveals some advantages of the microinjector over the conventional fuel injector.
Surface Micromachine Microfluidics: Design, Fabrication, Packaging, and Characterization
Authors: Galambos Paul , Eaton William P. , Shul Randy , Willison Christi Gober , Sniegowski Jeffry J. , Miller Samuel L. , Gutierrez Daniel 
Published: December 2021

Abstract
The field of microfluidics is undergoing rapid growth in terms of new device and system development. Among the many methods of fabricating microfluidic devices and systems, surface micromachining is relatively underrepresented due to; difficulties in the introduction of fluids into the very small channels produced, packaging problems, and difficulties in device and system characterization. The potential advantages of using surface micromachining include: compatibility with the existing integrated circuit tool set, integration of electronic sensing and actuation with microfluidics, and fluid volume minimization. In order to explore these potential advantages we have developed first generation surface micromachined microfluidic devices (channels) using an adapted pressure sensor fabrication process to produce silicon nitride channels, and the SUMMiT process to produce polysilicon channels. The channels were characterized by leak testing and flow rate vs. pressure measurements. The fabrication processes used and results of these tests are reported in this paper.
Pressure Sensors in Automotive Applications and Future Challenges
Authors: Chiou J. Albert 
Published: December 2021

Abstract
Silicon pressure sensors have been widely used in the automotive and health care industries since the last decade, especially in automotive applications. Initially, the sensors mounted in cars are used to reduce the emission pollution and improve the gas consumption. Today, sensors are commonly used in many automotive systems. High volume, low price, and small size are the major keys to the success of the automotive pressure sensor business. More mature micromachining operations, better understanding of material properties, improved mechanical packaging, better circuit and system design, higher volume production test, and application engineering to fit the end user system requirements are all important factors that contribute to the commercial success of pressure sensors.
A Technique for Determining the Mechanical Behavior and Electrical Performance of Thin Films
Authors: Li Li , Huang Biao , Qiao Q. , Gordon M. H. , Schmidt W. F. , Ang S. S. 
Published: December 2021

Abstract
We describe a technique to determine the mechanical behavior and electrical performance of thin films. Thin films (2 μm) are deflected with a probe, and the displacement of the thin films and total electrical resistance are recorded. Nonlinear finite element models (ANSYS) are used to predict the corresponding force and stress. Three microstructures are built and tested: cantilever (80 μm long and 100 μm wide), bridge (290 μm long and 50 μm wide), and cross (320 μm long and 30 μm wide). No failures are observed at 15 μm deflection for all three structures, and a yield strength at least 1.34 GPa (4–20 times larger than the reported bulk value, but consistent with thin film theory) is inferred. The measured total resistance for every device ranges from open to 0.2 Ω. A direct correlation between the measured resistance and numerically predicted force (or contact pressure since the same probe tip is used in all tests) is noted, validating the numerical predictions. The bridge and cross designs appear feasible as a burn-in test socket, and we predict a mating force of 80–350 N for a 25 mm square chip with 10,000 solder balls on 250 μm spacing. This force will depend on the acceptable range of resistances as measured by our system.
Design of a Vehicle Control System for Cloning of Human Driving Behavior
Authors: Schaefer Frank R. , Schuller Juergen 
Published: December 2021

Abstract
This paper discusses the development of a driver model designed to mimic human behavior for any kind of driving situation. A new concept is introduced to model human short term control. It is based on a strict separation of geometric dynamic planning and plan to action mapping. Such a division enables one to model the effects motivation and knowledge independently. Moreover, it facilitates the task of debugging since errors resulting from faulty geometric dynamic planning can be isolated from those that result from lack of knowledge about the system being controlled. This article is thought to give an overview of a driver system that is novel in its structure. This approach establishes vehicle control in a way that is different from traditional linear systems.
A method is introduced that allows one to model multiple aspects of motivation and combine them in a sound manner for the task of creating a geometric dynamic plan. Motivations are divided into two classes: target motivations and limit motivations. These kinds of motivation are represented by a method to construct target and limit maps. A discussion about how to combine these maps and find the optimum geometric dynamic plan concludes the discussion about geometric dynamic planning.
Plan-to-action mapping designates the process used to find the appropriate physical values by which the driver controls the vehicle, i.e. the front wheel angle velocity and the longitudinal tracking force. This is the point where knowledge about the system must be included.
Simulation results show how to distinguish between errors arising from geometric dynamic planning and errors arising from plan-to-action mapping. Finally, results demonstrate the ability of the driver to maintain control over the vehicle system even at the limit of adhesion.
A Topology for Vehicle Stability and Handling Enhancement via Wheelslip Control
Authors: Kimbrough Scott 
Published: December 2021

Abstract
Wheelslip is a measure of the longitudinal slipage between the tire and the ground. Tire forces are a function of wheelslip, and by controlling wheelslip, tire forces can be modified, which in turn, allows the vehicle trajectory to be modified. A general approach is described for determining appropriate wheelslip commands, commands that will produce beneficial effects on the vehicle stability and handling.
Development of a Media Equivalent as a Foundation for a Biomimicking Vascular Prosthetic
Authors: Pawlowski Kristin J. , Bowlin Gary L. 
Published: December 2021

Abstract
Development of an ideal vascular replacement has been addressed with increasing urgency in recent years. To date, appropriate replacements for only large diameter bypass have been realized, employing the use of Dacron and expanded polytetrafluoroethylene. A solution for small diameter vessel bypass, however, has not yet been found. This is due mainly to acute thrombotic occlusion and chronic anastomotic hyperplasia that is introduced into these grafts due to the low blood flow velocities experienced by smaller caliber vessels and compliance mismatch between prosthetic and native vessel, respectively [1].
Fluid and Solid Mechanics in Stented Arteries
Authors: Moore James E. , Berry Joel L. , Manoach Emil , Rachev Alexander 
Published: December 2021

Abstract
Vascular stents are being used in increasing numbers to correct arterial flow limiting disorders. Although data exist on the in vivo performance of these devices, comparatively little is known about how these devices affect the arterial mechanical environment. The long-term success of stenting is very likely affected by the blood flow patterns and artery wall stresses that follow stent placement.
This study was undertaken to identify the mechanical environment in stented arteries and to propose a stent design that minimizes the “mechanical trauma” of stent implantation. A series of pulsatile flow visualization experiments were performed with a Johnson & Johnson Palmaz/Schatz stent inserted in a straight compliant tube. A flow loop was constructed that was capable of applying a physiologic pulsatile flow indicative of conditions in the femoral or coronary arteries. The results showed that this stent design creates complex flow patterns including large-scale vortices, and that these patterns are caused by the compliance mismatch between the stented vessel and adjacent unstented vessel.
The compliance mismatch also would be expected to create abnormal stress concentrations in the artery wall near the ends of the stent. A simplified model of an artery was constructed to estimate the stress in the artery wall. The stent/artery structure was assumed to be an axisymmetric thin shell made of a linear elastic, orthotropic material that undergoes small deformations. The stent diameter was assumed to be equal to the artery systolic diameter. The stresses were estimated under diastolic pressure, when the deflection of the artery due to the presence of the stent is greatest. It was found that the circumferential and axial stresses at the ends of the stent were 2 to 3 times higher than the stress far from the stent.
Based on these mechanical studies, a new stent design was proposed that provides a smooth transition in compliance at the proximal and distal ends of the tube. Flow visualization studies with this new stent indicate that the flow disturbances are greatly reduced with this new design. The transition zone was incorporated into the shell model to estimate the artery wall stresses induced by this new model. It was found that the stress concentration was reduced by as much as 36% from the rigid stent value. These studies demonstrate the potential complexity of flow in stented arteries and provide some recommendations for optimizing stent design from a biomechanical point of view.
This work was supported in part by a Linkage Grant from NATO.