bluuebunny/crossref_metadata_2025_split huggingface dataset:
Heat Transfer and Critical Heat Flux of Forced Flow Boiling in Vertical-Narrow-Annular Passages
Authors: Koizumi Yasuo , Ohtake Hiroyasu , Fujita Yosinobu 
Published: November 2021

Abstract
The forced-convection flow boiling heat transfer in narrow-annular flow passages was experimentally examined by using R-113. The gap clearance and the mass flux were δ = 0.5 ∼ 10.0 mm and G = 102 ∼ 103 kg/m2s, respectively. When the clearance was narrow (δ = 0.5 and 1.0 mm), the critical heat flux (CHF) condition which was defined as the deviation from the fully developed nucleate boiling state occurred in the first place, then the wall temperature excursion (EXC) was initiated after a further increase in the heat flux. At the CHF condition, the wall temperature did not rise sharply. The difference between those heat fluxes, qCHF and qEXC, became small as the flow rate was increased. When the clearance became wide (δ ≥ 2.0 mm), the CHF condition and the EXC occurred simultaneously. The EXC heat flux qEXC increased sharply with an increase in δ until δ = 2.0 mm. In δ &gt; 2.0 mm, the increasing rate calmed down to show tendency reaching some asymptotical value, qEXC of the co-current flow was considerably higher, approximately ten times, than qEXC of the counter-current flow. The difference decreased as δ became wide. The critical heat flux, qCHF, correlation, which was developed by considering that whether the dried area which was created because of wearing-out of the liquid layer under a bubble could be rewetted or not decide the critical condition, predicted well the present experimental results of qCHF. However, when δ was extremely narrow such as δ = 0.5 and 1.0 mm, the heat transfer deterioration due to the appearance of a coalescent bubble occurred before the condition defined above, thus the correlation overpredicted qCHF.
Study on Velocity Profile Measurement Using Ultrasound Time-Domain Correlation Method
Authors: Yamanaka Gentaro , Kikura Hiroshige , Aritomi Masanori 
Published: November 2021

Abstract
This paper presents a velocity profile measurement technique using a ultrasound time-domain correlation method (UTDC). The system is based on the cross correlation between two consecutive echoes of ultrasonic pulses to detect the velocity. The UTDC has two advantages over a conventional ultrasound pulse Doppler method. First the system has a higher time resolution than the pulse Doppler method. Second, the system does not have a limitation in maximum measurable velocity, which is limited by Nyquist’s sampling theorem.
In this paper, the velocity profile measurement using the UTDC is performed, and the velocity profiles measured by the UTDC is compared with the one obtained using the pulse Doppler method.
The result showed that aliasing effect occured by the measurement of the pulse Doppler method but does not occured by that of the UTDC at the same pulse repetation frequency.
Generalized Mechanistic Force System Model of Ball-End Milling for Sculpture Surface Machining
Authors: Lazoglu Ismail 
Published: November 2021

Abstract
In this paper, a new mechanistic model is developed for the prediction of cutting force system in ball-end milling process. The key feature of the model includes the ability to calculate the workpiece / cutter intersection domain automatically for a given cutter location (CL) file, cutter and workpiece geometries. Moreover, an analytical approach is used to determine the instantaneous chip load and cutting forces. The model also employs a Boolean approach for given cutter, workpiece geometries, and the CL file in order to determine the surface topography and scallop height variations along the workpiece surface which can be visualized in 3-D. Some of the typical results from the model validation experiments performed on Ti-6A1-4V are also reported in the paper. Comparisons of the predicted and measured forces as well as the surface topographies show good agreement.
Geometry Analysis and Simulation in Shoe Centerless Grinding
Authors: Zhang Hong , Lieh Jungshen , Yen David , Song Xiaozhong , Rui Xiaojian 
Published: November 2021

Abstract
In this paper, the geometry relationship of shoe centerless grinding for predicting the profile of workpiece is presented. Based on the model, critical parameters are studied. The model was compared with experimental results obtained from grinding trials.
Grading and Motivation of Student Teams Working on Industry-Sponsored Mechanical Design Projects
Authors: Beale David G. , Simionescu P. A. , Dyer David 
Published: November 2021

Abstract
The guiding principles adopted for teaching the Comprehensive Mechanical Design course in the Department of Mechanical Engineering of Auburn University are presented. These were introduced to better serve the need for well-trained engineering personnel, where technical skills must be combined with good communication and management skills.
Pre-Processing of Heterogeneous Objects for Layered Manufacturing
Authors: Shin Ki-Hoon , Dutta Debasish 
Published: November 2021

Abstract
Layered manufacturing (LM) is emerging as a new technology that enables fabrication of three dimensional heterogeneous objects (such as Multi-materials and Functionally Gradient Materials). The steps for fabricating heterogeneous objects include model representation and material process planning. This paper introduces a method for processing the material information. It includes pre-processing (discretization), orientation (build direction selection), and adaptive slicing of heterogeneous objects. The discretization process converts all material information inside a heterogeneous object to material features like geometric features, thus it makes it possible to determine build direction by estimating build time based on geometric features and material features. It also allows adaptive slicing of heterogeneous objects to minimize surface finish and material resolution error. In addition, tool path planning can be simplified to fill pattern generation. Examples are shown.
On the Driving Mechanism Design for Large Amplitude Electrostatic Actuation
Authors: Hsieh Jerwei , Chu Chien-Cheng , Fang Weileun 
Published: November 2021

Abstract
This study intends to improve the performances of conventional electrostatic actuator regarding its amplitude and driving force. Two approaches including the oblique-comb actuator design and 2-DOF vibration system for amplitude amplification are proposed. The former has advantages in both generated force and allowable stroke, while the latter has the nature of larger output amplitude driven by smaller input stroke. Base on the advantages of both methods, the combination of these two designs can further improve the performance regarding output amplitude and driving voltage.
Flip-Chip Fabrication of Advanced MEMS Using a Novel Latching Off-Chip Hinge Mechanism
Authors: Michalicek M. Adrian , Bright Victor M. 
Published: November 2021

Abstract
This paper presents the design, fabrication and implementation of a novel off-chip hinge mechanism that can be latched in place to hold surface-micromachined structures off the edge of the chip. This mechanism was designed to enable fast, reliable, accurate, simple, and low-cost fabrication of advanced flip-chip MEMS structures. The upper layers of a flip-chip device can be commercially prefabricated on a host module attached to the hinge mechanism while the lower layers can be prefabricated on virtually any desired receiving module. This paper presents the design, fabrication and testing of a variety of advanced micromirror arrays assembled using this mechanism. This research demonstrates that structures comprised of several surface-micromachined layers can be positioned and bonded onto a variety of work surfaces such as ceramic substrates, MEMS chips and even CMOS electronics using adhesives, solder, gold bonding or mechanical latches. The hinge mechanism is designed to be easily disabled by a variety of methods should another bonding technique be desired. All flip-chip modules are designed with the mechanism to enable multiple flip-chip assembly options.
A Magnetically Actuated, Electrostatically Clamped High Current MEMS Switch
Authors: Choi Yoonsu , Kim Kieun , Allen Mark G. 
Published: November 2021

Abstract
MEMS switches based on a dual actuation scheme that simultaneously allows for large standoff heights and low clamping voltages have been fabricated. The switches consist of a magnetically-driven component and an electrostatically-driven component. These devices are based on the use of a transient external magnetic field to bring the actuating portion of the switch (made of electroplated NiFe) close to a dielectric-coated clamping electrode, followed by application of an electrostatic clamping voltage to keep the switch closed. Since the clamping voltage is applied when the switch is closed, this voltage can be relatively small. This approach is particularly attractive for reconfigurable arrays of switches. Arrays of switches are simultaneously closed by the magnetic field generated by an off-substrate magnetic source. Selected switches are clamped by electrostatic force using low voltages to maintain the ON state. With this scheme, reconfigurable patterns on an array of switches are possible. These switches possess a large open state air gap (25–35 μm), and are able to pass high currents in excess of 1 A. The large OFF state impedance, then, allows for their usage in switching applications in reconfigurable aperture antennas.
Pirani Pressure Sensor With Distributed Temperature Sensing
Authors: van Baar J. J. , Wiegerink R. J. , Lammerink T. S. J. , Krijnen G. J. M. , Elwenspoek M. 
Published: November 2021

Abstract
A Pirani pressure sensor is based on the fact that the thermal conductivity of a gas is dependent on the pressure. The structure presented in this paper consists of a heated microbeam, which is placed above a v-groove in a heat sink. The temperature distribution along the microbeam is a measure for the thermal conductivity of the surrounding gas. Measuring the temperature distribution instead of the average temperature of the beam has two advantages: the measurement becomes independent of the Temperature Coefficient of Resistance of the temperature sensing resistors and the heat loss to the substrate is implicitly taken in account, which extends the lower pressure range.
Omnidirectional Walking Microrobot Realized by Thermal Microactuator Arrays
Authors: Mohebbi Matthew H. , Terry Mason L. , Böhringer Karl F. , Kovacs Gregory T. A. , Suh John W. 
Published: November 2021

Abstract
An omnidirectional mobile microrobot realized by micro-electromechanical system (MEMS) actuator arrays is presented. The microrobot consists of two rigidly connected microcilia array chips, each having an 8 × 8 array of “motion pixels,” which are composed of four orthogonally oriented thermal bimorph actuators. This allows for reliable, accurate motion in three degrees of freedom (x,y,θ) in the plane, a first for a microrobot of this kind. The microrobot is approximately 3cm in length, 1cm in width, 1mm in height, and has a mass of less than half a gram. By varying the input power, actuation frequency and motion gait strategy the velocity of the chip can be precisely controlled. Motion in three degrees of freedom has been demonstrated and a maximum velocity of 635 μm/s and carrying capacity greater than 1.448 g (two 8-pin ICs) has been observed. The microrobot has been characterized extensively and a model for its performance is described.
Design and Fabrication of High Power Electromagnetic Microactuator With Perpendicular Magnetic Anisotropy
Authors: Pan C. T. , Shen S.-C. , Chou H.-P. 
Published: November 2021

Abstract
A novel microactuator has presented by this research. The high power electromagnetic microactuator combines of innovative hard magnetic Fe/Pt process, high Ni/Fe permalloy magnetic circuit design technique, bulk micromachining and excimer laser ablation. The hard magnetic material is Fe/Pt which is deposited under low temperature by sputter on the suspension diaphragm to offer perpendicular magnetic anisotropy field. The magnetic circuit with close loop is applied to concentrate the magnetic flux and increases magnetic force. Therefore, the magnetic field induced by the magnetic field of the planar coil and Ni/Fe permalloy can be enhanced, which will interact with Fe/Pt and induce huge displacement, large force output and high frequency. The high power electromagnetic microactuator has been demonstrated magnetic force 2 times larger than conventional magnetic microactuator.
MEMS Metrology Using Resonant Structures
Authors: Allen A. Miller , Johnson George C. 
Published: November 2021

Abstract
We present an analytical method and experiment to determine the “as-built” geometry of surface micro-machined micro-electromechanical structures. The analysis is based on the use of the lateral resonant frequencies of electrostatic comb drive resonators. The method can be used in situ and does not require a priori knowledge of the mechanical material properties of the structure. The variation between designed geometry and “as-built” geometry is determined from a fit of experimental results to the analytical model.
Building a ‘Design-to-Analysis’ Interface for Summit™-Based Microsystem Development
Authors: Wong C. Channy , Jorgensen Craig R. , Yarberry Victor R. , Ho Pauline , Pawlowski Roger P. , Freymiller James , Melander Darryl J. 
Published: November 2021

Abstract
As the design for microsystems becomes increasingly more complex, the ability to predict and visualize thin-film structures during the design phase becomes correspondingly important. Virtual prototyping is definitely needed. However, accurately predicting the dimensions of the final product will require that the true effects of the surface micromachining processes be modeled. At Sandia, we are developing an integrated software package that links microsystem design with visualization and performance analysis. This integrated package consists of physical models that can generate the correct shape of micro-features. This paper describes our initial effort, which is twofold: (1) to build a generalized 3-D CAD package that interfaces between the microsystem design tools and analysis tools, and (2) to develop a modeling capability that predicts the general shape of fundamental micro-features from the fabrication process. A demonstration to illustrate how the ‘design-to-analysis’ infrastructure is being integrated will also be presented.
Achieving Close Frequency Match Without Incurring Instabilities in Micro Gyros
Authors: Haney J. D. , Feng Z. C. 
Published: November 2021

Abstract
We study the nonlinear dynamics of the MEMS micro gyro to guide the structural design of the sensor. The nonlinearity is a result of the small but finite rotations of the gyro structure. The equations of motion are studied numerically. Nonlinearity of the gyro system is demonstrated through the determination of the resonance frequencies. The resonance frequencies are shown to be affected by the oscillations in the other modes. Even though the frequency variations are small, they are significant because the micro gyro structures have an unusually high Q value (i.e. low damping ratio). The nonlinear coupling between the drive mode and the sense mode has been shown to give rise to instability of the drive mode motions. Numerical solution further verifies that. Moreover, we determined the region in the parameter space containing the frequency detuning in which instability occurs. For parameters outside the region, the instability can be avoided.
Micro-Isolation Valve for Fuel Tank Array
Authors: Takahashi Koji , Nagayama Kunihito , Yasaka Tetsuo , Asano Tanemasa 
Published: November 2021

Abstract
Isolation valve system for low-cost liquid tank array is designed and demonstrated. This valve is normally closed and opens only once for liquid injection. This array system can supply precise amount of liquid at each operation as many times as the number of tanks. In order to tolerate the ambient high pressure and to accomplish the perfect injection, a large and thick membrane is fabricated and tested as valve. Without any special structure, our valves are found to open just by applying low AC voltage to a pair of electrodes that are apart from each other by tens of micrometers. Dielectric breakdown and pressure increase inside tank are found to work effectively to form a large hole.
A Novel Attitude Control Technique for Miniature Spacecraft
Authors: Li Jun , Koh Sung K. , Ananthasuresh G. K. , Ayyaswamy P. S. , Ananthakrishnan S. 
Published: November 2021

Abstract
A novel attitude control technique for miniature spacecraft using MEMS actuators is presented in this paper. In this technique, a permanent net change in the orientation of the spacecraft is achieved even though the individual microactuators are all brought to their unactivated state at the end of an attitude-changing maneuver. This is ideally suited for untethered systems such as spacecraft because continuous supply of power is not necessary to retain the new orientation. The technique exploits the non-commutative property of finite rotations of a rigid-body. That is, a sequence of fully-reversed rotations about three orthogonal axes results in net change in the orientation of the spacecraft. The limited torque capacity of microactuators is overcome by using an array of actuators and accomplishing the attitude-change maneuver in several small steps. An ensuing problem of planning such a maneuver is stated. The practical feasibility of the technique is demonstrated using electro-thermal microactuators.
A Large-Angle and Large-Mirror Microscanner Based on Thermal Actuators
Authors: Tu Ching-Chen , Liu Cheng-Hsien , Du Chen-Hsun , Tsaur Jiunn-jye , Lee Chengkuo 
Published: November 2021

Abstract
In this paper, we present a large-scanning-angle and large-mirror microscanner actuated by the thermal actuators. The thermal actuators are based on bimorph effect and consist of three thin film layers, Polyimide, Au, and SiO2. The large mirror is released rapidly by using poly-pad combined with surface micromachining and bulk micromachining. The actuator has the adventure of low power consumption from our design. Furthermore, our microscanner can achieve the purposes of self-assembly and out-of-plane by residual stress after curing processes.
Effects of Stress Induced by the Underlying Layers on the Micro-Structures and Characteristic Phase Transformation Temperatures of Sputtered TiNi Thin Films
Authors: Wang Rong Xin , Zohar Yitshak , Wong Man 
Published: November 2021

Abstract
The micro-structures and the phase transformation temperatures of sputtered titanium-nickel (TiNi) thin films, both free-standing and attached on different underlying multi-layer substrates have been studied. Differences in the micro-structures, such as the lattice constants and the relative concentrations of TiNi, Ti2Ni and TiNi3 phases, were observed (1) among the free-standing and the attached films, (2) among the films attached on different underlying multi-layers and (3) among films with different relative orders of aging and release. Not surprisingly, the corresponding phase transformation temperatures are also different. It is proposed that both substrate- and process-induced stress significantly affect the micro-structures, hence the phase transformation characteristics, of the resulting shape-memory alloy thin films.
Calibration of MEMS Strain Sensors Fabricated on Silicon
Authors: Cao Li , Hautamaki Chuck , Zhou Jia , Kim Tae Song , Mantell Sue 
Published: November 2021

Abstract
A calibration technique for measuring MEMS strain sensor performance is described. The sensor calibration technique entails developing a repeatable relationship (gage factor) between the change in sensor nominal resistance and the strain measured at the sensor. The calibration technique involves creating a “pseudo” strain sensor consisting of a strain gage mounted on a silicon wafer. Two identical test specimens are evaluated: the pseudo sensor mounted (with adhesive) on an aluminum specimen (or embedded in a specimen), and a MEMS strain sensor mounted on an aluminum specimen (or embedded in a specimen). The dimensions of the silicon wafer for both the pseudo sensor and MEMS sensor are identical. The specimens are loaded by tensile test. For the pseudo sensor specimen, a relationship is established between the strain applied to the specimen (far field strain) and the strain at the sensor (near field strain). Once the relationship between near field and far field strain is known, a relationship between near field strain and change in resistance of the uncalibrated MEMs sensor is established. This relationship between strain at the sensor and change in resistance is the gage factor. Two different MEMS strain sensor designs were fabricated by patterning polysilicon on a 500 micron thick silicon wafer: monofilament and membrane sensors. Gage factors for the MEMS sensors were determined following the calibration procedure. The results also lead to a conclusion that wafer geometry influences the strain transfer to the sensor.
Friction and Tribological Considerations for Nanometer Range Machining
Authors: Chattopadhyay Som 
Published: November 2021

Abstract
Positioning accuracy within the range of nanometers is required for high precision machining applications. The implementation of such a range is difficult through the slides because of (a) irregular nature of friction at the slider-guideway interface, and (b) complex motion characteristic at very low speeds. The complexity arises due to the local deformation at the interface prior to breakaway, which is known as microdynamics. In this work prior experimental results exhibiting microdynamics have been appraised, and mathematical model developed to understand this behavior.
Deep Reactive Ion Etched Submicron Beam/Trench Characterization
Authors: O’Brien Gary , Cheng Xing , Guo L. J. 
Published: November 2021

Abstract
Sub-micron width high aspect ratio beam/trench arrays are etched into silicon substrates using a Surface Technology Systems (STS) deep reactive ion etch (RIE) tool equipped with a time multiplexed plasma etch/passivation cycle scheme. The oxide mask is patterned by nanoimprint lithography and minimizes lateral trench etching by adjusting the significant etch parameters. High aspect ratio trench arrays 350nm wide with a 700nm period are etched to a depth of 10 μm with typical sidewall asperities on the order of 30nm. A dual etch process is used to reduce scalloping near the trench surface using HBr/Cl to etch the initial 500nm followed by the STS process using C4F8/SF6 chemistry. The dual etch process resulted in a reduction of sidewall asperities from 75nm to less than 25nm. In addition, the dual etch process reduced the trench array depth variation from a measured standard deviation of 0.7 to 0.1 representing significant improvement of etch repeatability across the wafer sample.
Analysis of Time Periodic Electroosmotic Flows
Authors: Dutta Prashanta , Beskok Ali 
Published: November 2021

Abstract
Analytical solutions of time periodic electroosmotic flow in two dimensional straight channels are obtained as a function of a nondimensional parameter k, which is based on the electric double layer (EDL) thickness, kinematic viscosity and the frequency of the externally applied electric field. A parametric study as a function of k reveals interesting physics, ranging from oscillatory “plug-like” flow in the quasi-steady state to flows analogous to the oscillating flat plate in unbounded flow domain (Stokes’ second problem). The latter case differs from Stokes’ second solution within the EDL, since the flow is driven with oscillatory electric field, rather than a moving surface. Utilization of the instantaneous Helmholtz Smoluchowski velocity as the slip boundary condition on the wall matches the bulk flow solution accurately, even for high, frequency excitations. Unlike the steady electroosmotic flows, the vorticity for time periodic electroosmotic flows is not confined in the EDL.