bluuebunny/crossref_metadata_2025_split huggingface dataset:
Numerical Simulation of Gas Flows in Micro-Filters
Authors: Ahmed Imtiaz , Beskok Ali 
Published: November 2021

Abstract
Gas flows through micro-filters are simulated in the continuum and slip flow regimes as a function of the Knudsen, Reynolds and Mach numbers. The numerical simulations are based on the spectral element formulation of compressible Navier-Stokes equations, which utilize previously developed high-order velocity slip and temperature jump boundary conditions. Both slip and no-slip simulations are used to identify the rarefaction effects. The simulation results show skin friction and form-drag reduction with increased Knudsen number. Pressure drops across the filters are compared against several empirical scaling laws, available in the literature. Compressibility becomes important for high-speed flows, creating large density fluctuations across the micro-filter elements. For high Mach number flows, interactions between thermal and kinetic energies of the fluid are observed. It is also shown that viscous heating plays a significant role for highspeed gas flows, impacting heat transfer characteristics of micro-filters.
A Fast Algorithm for Particulate Micro-Flows in Complex Geometries
Authors: Liu D. , Maxey M. , Karniadakis G. E. 
Published: November 2021

Abstract
An approximate description for the motion of particles in a liquid flow is pesented that forms the basis for an efficient numerical simulation procedure. The method is based on a spatial distribution of finite force multipoles and requires much less resolution than full DNS. The numerical implementation is summarised and example results given for Stokes flow and low Reynolds number flow in a channel and in a channel with a contraction. Comparisons are made with DNS results and experimental data.
Two-Phase Flow Boiling in a Microchannel Heat Sink
Authors: Lee Man , Wong Yiu Yan , Wong Man , Zohar Yitshak 
Published: November 2021

Abstract
A micro heat sink comprising 10 microchannels integrated with a local heater and a temperature microsensor array has been fabricated on a silicon wafer using standard micromachining techniques. A glass wafer was anodically bonded to the silicon wafer in order to cap the trapezoidal microchannels, about 14μm in depth and 120μm in average width. DI water was pressurized through the heat sink serving as the working fluid. Boiling curves of device temperature, at a few locations along the centerline, were measured as a function of the input power. In contrast to previously reported results, the boiling plateau associated with latent heat of phase change from liquid to vapor was detected. The transparent glass ceiling allowed the visualizations of flow phenomena dominated by surface effects. The classical bubble dynamics of bubble formation, growth, and detachment was observed at relatively low input power. However, this mode was completely suppressed at moderate power levels. Further increase of the input power resulted in a clear separation between the upstream vapor and the downstream liquid. The average location of the vapor/liquid interface shifted downstream with the input power, and near the critical heat flux condition the interface was located at the channel outlet. Thus, the added heat resulted in increased quality of the two-phase flow rather than increasing the mixture temperature.
Dynamics of Field Amplified Sample Stacking
Authors: Bharadwaj Rajiv , Santiago Juan G. 
Published: November 2021

Abstract
We present an analysis and an experimental study of field amplified sample stacking. The analysis consists of a one dimensional, unsteady electromigration model of the concentration fields in sample stacking. The model predicts that the sample concentration develops as a non-linear concentration wave with a peak concentration increasing with time that reaches a maximum value determined by ratio of electric fields in the sample and the buffer region. The experimental work is a preliminary study of the effects of electroosmotic flow on sample stacking for a single fluid-fluid interface within a glass microchannel. Using a simple cross-channel configuration a high-gradient initial step-function in the buffer concentration field was established which causes an unsteady sample concentration process. The experimental results qualitatively confirm the wave-like profile of the stacked analyte predicted by the analytical model. Experiments also provide evidence of internal pressure generation due to mis-matched electroosmotic velocities during stacking. The effect of electric field strength and sample-to-background buffer concentration ratio, γ, are also presented. Stacked sample concentration at γ = 4 is found to initially increase with increasing electric field but saturates at higher electric fields. Stacking rates at higher γ ratios indicate that concentration enhancement is quickly limited by dispersion due to internally generated pressure gradients.
A Large Flowrate Electroosmotic Pump With Micron Pores
Authors: Yao Shuhuai , Huber David , Mikkelsen James C. , Santiago Juan G. 
Published: November 2021

Abstract
This paper presents a description of the design, fabrication, and characterization of a novel, high flowrate electroosmotic pump designed for microcooling applications. The prototype pumps demonstrated a flowrate of 7 ml/min for 200 V applied potential that is suitable for two-phase heat exchangers with a capacity approaching 100 W. This pump uses electroosimotic flow (EOF) to drive the flow and is compact with no moving parts. The pump structure is produced by chemically treating and further sintering an ultrafine glass frit (filter). The frits we use are porous cylinders 30 mm in diameter and 3 mm (varying from 1.5 to 3 mm) thick and provide the high wetted-surface-to-volume ratio required to generate pressures exceeding 2 arm. Both deionized (DI) water and buffered aqueous solutions have been used as working fluids. Experiments have been conducted to characterize the pump performance and investigate its physical properties such as the structure porosity, tortuosity, effective pore size, finite double layer effects, and the dependence of zeta potential on ionic conductivity of the working solution.
Velocity Measurements of Flow Over Hydrophobic Microchannel Walls
Authors: Tretheway Derek C. , Meinhart Carl D. 
Published: November 2021

Abstract
This work addresses the controversy of slip of a hydrophilic fluid over a hydrophobic boundary by applying micron resolution particle image velocimetry (μ-PIV) to measure the flow profiles of water flowing through 30 × 300 micron channels that have a clean surface (hydrophilic) and channels coated with hydrophobic molecules, OTS (octadecyltrichlorosilane). The results for hydrophilic liquids flowing over hydrophilic boundaries are consistent with the no-slip boundary condition. However, the results show that the no-slip boundary condition is not necessarily valid for hydrophilic liquids flowing over hydrophobic boundaries. Thus, modeling fluid flow at the micro-scale with the assumption of no-slip may or may not be valid, but will depend on the interactions between the fluid and the surface properties of the wall.
Selective Induction Heating for MEMS Packaging and Fabrication
Authors: Cao Andrew , Lin Liwei 
Published: November 2021

Abstract
Selective induction heating has been applied to metallic micro-loops patterned on a glass substrate. These aluminum loops enclosed areas ranging from 300 × 300μm2 to 1000 × 1000μm2. They have a thickness of 4μm and widths ranging from 30μm to 150μm. Induction heating is achieved remotely by using a helical coil driven at 14.2 MHz. When 1kW of heating power is applied for 150ms, it is found that the 1000 × 1000μm2 aluminum loops are heated to a high temperature of at least 1100°C. A finite element model is established to estimate the heat transfer process and it is found that the heat generation rate should be at least 9 × 1012 W/m3 and at least 8 watts of power is induced in the aluminum loop locally and selectively. Furthermore, Pyrex substrate does not heat up under induction heating and heating of silicon substrate is highly dependent on the doping level. It is believed that with proper design and material selection, this remotely applied selective heating method can be applied for MEMS bonding and fabrication process.
A Novel Device-Level Micropackaging Using Micro Assembly Transfer
Authors: Chen Jen-Yi , Huang Long-Sun , Chu Chia-Hua , Kuo Yao-Hui , Chang Peizen 
Published: November 2021

Abstract
A novel device-level micropackaging that may encapsulate functional devices in post packaging has been developed. The encapsulation is formed with a metallic microcap like a dome shape to shield necessary micro devices from external impact or contamination. The metal cap is initially fabricated on a carrier glass and then transferred onto a host substrate. In this micropackaging, the micro assembly transfer and cap leg-snapped techniques are utilized in successfully demonstrating the transferred cap on the selected area of the host substrate that is aligned through the transparent glass. The low temperature solder bonding also allows this technique to be compatible with existing integrated circuit and micromachined devices. Furthermore, the robustness of the electroplated micro cap is even superior to the reported surface micromachining technique due to the high stiffness of a thicker structure by controllable electroplating. With the effective aid of the numerical analysis of the cap leg, the fracture can be expected at a desirable spot in which the stress concentration occurs under pulling forces for separation of the carrier glass and the cap. As a result, the micro encapsulation presents a successful, new packaging technique with advantages of selective 3D micro packaging, sealing, robustness, back-end process compatibility and potentially low cost.
An Acoustic Procedure for Measuring Blade-Frequency Forces Generated by Model Ship Propellers
Authors: Strasberg M. 
Published: November 2021

Abstract
An acoustic procedure is described for measuring the blade-frequency fluctuating forces developed by a powered model propeller operating behind a model of a ship’s hull or a wake generator in the anechoic test section of a wind tunnel. The sound pressure radiated by the propeller in a given direction is measured and its magnitude inserted into a simple theoretical relation to determine the alternating force developed by the propeller in that direction. Although the procedure was developed years ago, the details and limitations have not previously been described in the literature. Restrictions are discussed on the size of the propeller, location of the measurement point, measurement frequency, and the wind speed. Measurements determining the validity of the procedure are described, including comparisons of the magnitude of forces determined by this acoustic procedure with direct measurements made with a force dynamometer in a water tunnel.
Array-Based Methods of Characterizing Piping Component Acoustic Behavior
Authors: Conti Matthew , Stokes Ann , Corrado Charles 
Published: November 2021

Abstract
We present recently developed experimental methods of estimating acoustic scattering matrix representations of piping components such as valves and bends. Scattering matrices quantify the frequency dependent reflection and transmission coefficients for a wave incident on a device, and include terms representing the conversion of energy from one wave type to another. Scattering matrix representations of individual components can be embedded in a transmission line model to numerically assess acoustic transmission through a full piping system. This paper addresses both the experiment design and signal processing algorithms required to measure the scattering matrix.
Efficient Component-Based Vibration and Power Flow Analysis of a Vehicle Structure
Authors: Tan Yung-Chang , Lee Soo-Yeol , Castanier Matthew P. , Pierre Christophe 
Published: November 2021

Abstract
A case study on the efficient prediction of vibration and power flow in a vehicle structure is presented. The modeling and analysis technique is based on component mode synthesis (CMS). First, the finite element model (FEM) of the entire vehicle structure is partitioned into component models. Then, the Craig-Bampton method is used to assemble a CMS model of the vehicle. The CMS matrices are further reduced by finding characteristic constraint (CC) modes. A relatively small number of CC modes are selected to capture the primary motion of the interface between components, yielding a highly reduced order model of the vehicle vibration in the low- to mid-frequency range. Using this reduced order model (ROM), the power flow and vibration response of the vehicle is analyzed for several design configurations. A design change in one component structure requires a re-analysis of the FEM for that component only, in order to generate a new ROM of the entire vehicle. It is found that this component-based approach allows efficient evaluation of the effectiveness of the vehicle design changes.
Computation of Sound Transmission Loss and Absorption Coefficient of Multi-Layer Systems
Authors: Hong K. L. , Raveendra S. T. 
Published: November 2021

Abstract
Sound transmission and absorption of multi-layer sound absorbents are discussed in this manuscript. A new matrix formulation based on four pole parameters is utilized to derive the transmission loss and absorption coefficient of the absorbents. A transfer matrix relating pressure to acoustic velocity provides the required information to calculate the transmission loss and absorption coefficient. The multi-layer sound absorbents considered are structural panels, elastic porous linings and air-gaps. No limitations are imposed on the number of layers. Some realistic configurations of a multi-layer sound absorbent are studied to demonstrate the applicability of the four-pole parameter technique.
Variable Gap-Reluctance Linear Motor With Application to Linear Resonance Compressors
Authors: Popham Vernon W. , Lawrenson Christopher C. , Burr Ronald F. , Lipkens Bart 
Published: November 2021

Abstract
Variable gap-reluctance linear motors operate on the principle of electromagnetic attraction across an air gap between a moving armature and a stator and coil, which minimizes reluctance or stored magnetic energy. The direction of motion, force and magnetic field are aligned and are perpendicular to the air gap. When the air gap and corresponding stroke are moderate, large amounts of force and power can be delivered from a compact design. Several sizes of a new variable gap-reluctance linear motor design have been developed, characterized and applied. Practical application is demonstrated for linear resonance diaphragm refrigerant and gas compressors. A leaf spring suspension is used to dynamically match the motor to the resonance compressor load. Analysis and experimental results are combined to develop and characterize both the basic motor and integrated compressor designs.
Recent Developments in Thermoacoustic Engine-Generators
Authors: Corey John A. 
Published: November 2021

Abstract
The simplicity of thermoacoustic engines promises power at low cost and high reliability, but demands a second output conversion, from acoustic to more useful form. Electric output is the most highly prized form. At CFIC, and now Q drive, we have been experimenting with our resonant linear alternators as active dynamic components in thermoacoustic machines, providing this conversion. This paper presents the reasons for considering such a system, implications on design, and the results of CFIC’s prototype testing so far.
Simplified Dynamic Models of Submerged Objects From Limited Scattering Data
Authors: McDaniel J. Gregory , Clarke Cory L. 
Published: November 2021

Abstract
This paper investigates dynamic models of submerged objects which are obtained by acoustically ensonifying an object and measuring the scattered field at a single point while varying frequency. From such measurements, one can compute an effective impedance that physically represents the impedance of a half-space that would reflect a normally incident plane wave with the same amplitude as the wave scattered by the object. This effective impedance is shown to be passive and causal when the magnitude of the scattered wave is less than one. The effective impedance is related to reflection and impedance matrices matrices that arise in network formulations for the scattering of plane and spherical waves.
Acoustic Diffraction by a Half-Plane in a Viscous Fluid Medium
Authors: Davis Anthony M. J. , Nagem Raymond J. 
Published: November 2021

Abstract
We consider the diffraction of a time-harmonic acoustic plane wave by a rigid half-plane in a viscous fluid medium. The linearized equations of viscous fluid flow and the no-slip condition on the half-plane are used to derive a pair of disjoint Wiener-Hopf equations for the fluid stresses and velocities. The Wiener-Hopf equations are solved in conjunction with a requirement that the stresses are integrable near the edge of the half-plane. Specific wave components of the scattered velocity field are given explicitly, and the complete scattered velocity field is given in a form that is suitable for numerical computation.
Tuning a Replica of the Liberty Bell via Material Tailoring: An Application of a Method for Optimal Acoustic Design
Authors: Koopmann G. H. , Ericson David , Olchowski Adam , Salesky Eric 
Published: November 2021

Abstract
In this paper we describe a method for optimally tuning a bell to ‘best fit’ a specified sound spectrum. The method links the disciplines of structural dynamics, acoustics and optimization into a unified methodology. The design variables center on the addition of masses (size, number and location). The design variables are treated as external forces (via their impedances) in the equation that describes the bell dynamics as a series expansion of eigen functions. This step eliminates the need for solution of large matrix eigenvalue problems. An acoustic program POWER is used to assess the bell’s radiated sound power as a function of the design variables. Various search engines are used within the computer program MATLAB® to determine which design variables give the ‘best fit’ to the acoustic specifications.
On the Safety of Infeeding Vertical Garden Shredders
Authors: Brickman Dennis B. , Barnett Ralph L. 
Published: November 2021

Abstract
This paper addresses consumer garden shredders of the hammermill type with vertical hoppers that are manually fed. The purpose of this paper is to show that garden materials presented to a vertical garden shredder through the inlet hopper will not pull an erectly standing operator’s hand into the flails. In order for an erectly standing operator to contact the flails, it is necessary for the shoulder to move downward. Experiments demonstrate that the operator’s shoulder moves insignificantly downward during pull-in excursions using various garden materials that are attached to the operator’s hand through snagging mechanisms, hand friction, and entanglement.
Children’s Outerwear Drawstrings and Sliding Board Safety Analysis
Authors: Brickman Dennis B. 
Published: November 2021

Abstract
A two year old child strangled to death when the drawstrings of her jacket became lodged in a catch point hazard at the top of a residential sliding board. Approaches utilized in the safety analysis include accident reconstruction, safety literature review, standards research, an accident statistics survey, and an evaluation of alternative jacket and sliding board designs. Results of the analysis indicate there are technically and economically feasible design alternatives which prevent the child strangulation hazard associated with the jacket drawstrings and sliding board.
Use of Qualitative Risk Analysis to Prioritize Project Risk Reduction Efforts
Authors: Lindsey Pamelyn G. , Soczek Charlie A. 
Published: November 2021

Abstract
The risk associated with a highly toxic bulk storage facility was evaluated using a DuPont Qualitative Risk Assessment Protocol. The protocol used for the evaluation will be presented along with the results of the assessment. By application of this method a capital savings opportunity of over $500,000 can be realized as compared to the initial project scope estimate. These potential savings result from implementation of risk reduction measures based on an evaluation of both acute and chronic health effects on workers and the community. Additional process hazards analyses will be conducted to ensure adequate risk mitigation is implemented as the project design is finalized.
The Risk Based Allocation of Safety Integrity Levels for Machinery Control Systems and the International Standard IEC 62061
Authors: Worsell Nicola , Wilday Jill , Chambers Colin 
Published: November 2021

Abstract
This paper outlines the draft international standard IEC 62061 – Safety of machinery – Functional safety – Electrical, electronic and programmable electronic control systems [1]; this is intended to be a machinery sector implementation of the basic safety publication IEC 61508 – Functional safety of electrical/electronic/ programmable electronic safety-related systems [2]. A fundamental concept of IEC 61508 is the definition of safety performance criteria for safety functions implemented by safety-related electrical, electronic and programmable electronic systems in terms of safety integrity levels (SILs). This paper, therefore, goes on to describe a methodology, currently under development, for the risk based selection of SILs that it is proposed should be incorporated into an informative annex of IEC 62061.
The Impact of Safety Mitigation to Reliability of Co-Generation Units
Authors: Balkey Joseph P. 
Published: November 2021

Abstract
Companies may be considering improving their power reliability by installing one or more new co-generating unit(s) in addition to buying power. However, they may be unaware that the safety devices that protect the unit(s) may also inadvertently shutdown the unit(s). This paper first describes how a co-generation unit operates and some of its safety features. One of the safety features is to shutdown the unit when a temperature is inadvertently high. However, the number of instruments used to measure a temperature greatly impacts both safety and reliability. This paper graphically shows the simultaneous impact of four types of voting to both safety and reliability and discusses the purpose of each one. Knowing the purpose of each type of voting can lead to selecting a co-generation unit that matches a users needs. This paper also shows how the values in the graph are calculated.