bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fabrication of Novel Polysilazane MEMS Structures by Microcasting
Authors: Liew Li-Anne , Cross Tsali , Bright Victor M. , Raj Rishi 
Published: November 2021

Abstract
This paper presents a technique to fabricate MEMS from a novel, optically transparent polysilazane material. Polysilazane is a hybrid organic/inorganic polymeric glass that is highly transparent in the infrared to ultraviolet range and exhibits thermal stability superior to that of organic glasses such as polycarbonate and PMMA at temperatures up to 230 °C without losing optical transparency. In addition, the UV absorption of the polysilazane is closer to that of silicate glass than to pure organic polymeric glasses. This paper is the first reported work on fabricating MEMS out of this novel material, which has many potential applications in optical MEMS. The fabrication process based on casting in micro molds made photolithographically from SU8 photoresist is described, and a fundamental study of the cure depth of the polysilazane is reported. A polysilazane phase transmission grating is fabricated and demonstrated as a proof of concept optical device.
A Batch Fabrication Micro-Ball Array for Optical Coupling in Free Space Communication
Authors: Shen S.-C. , Chou H.-P. 
Published: November 2021

Abstract
The paper presents novel concepts of batch fabrication of micro-ball lens array technology integrated on the silicon-based wafer by which can improve appropriate distance for optical fiber coupling. The silicon-based optical coupling platform consists of the self-parking framework (including flat-topped mesa and intersection of two v-grooves) and micro-ball lens array for optical fiber coupling purpose. The structure of optical coupling platform is able to improve distance between fiber and micro-ball lens and to increase coupling efficiency. Optical measurement reveals an insertion loss below 2.5dB with wavelength 635nm in single-mode fiber. The micro-ball lens array is batch fabricated by polymeric material and thick photoresist, and then bonded them onto flat-topped mesa correspondently that adjoins to the v-groove. The corner compensation offers a method to fabricate flat-topped mesa in the intersection of two v-grooves. This fabrication process not only provides accurate coupling distance between fibers and micro-ball lens, but also reduces micro-assembly cost.
An Experimental Investigation of Flow-Induced Cavity Resonance
Authors: Zoccola Paul J. , Farabee Theodore M. 
Published: November 2021

Abstract
Excitation of cavity resonance by flow over an aperture is often a source of unwanted noise in aerospace, automotive, and marine applications. An experimental investigation of this phenomenon was conducted. Detailed measurements of the cavity pressure and the velocity field in the opening were performed in a quiet flow facility. Spectral data on cavity pressure fluctuations obtained for a variety of configurations were analyzed over a range of speeds to determine the behavior of both sheartones and cavity tones during non-resonant and resonant conditions. The mean and fluctuating velocity profiles as well as the cross-spectral properties between the velocity components and cavity pressure were also obtained within the cavity opening. Phase between the velocity components and the pressure was used to calculate the streamwise convection velocities across the opening. A novel technique used to measure vorticity allowed calculation of the measured energy production in the opening. The data support the finding that the resonant and non-resonant conditions are distinguished by the behavior of the convection velocity and by the distribution of energy production in the flow field.
Lifting Surface Flow, Pressure, and Vibration at High Reynolds-Number
Authors: Bourgoyne Dwayne A. , Judge Carolyn Q. , Hamel Josh , Ceccio Steven L. , Dowling David R. 
Published: November 2021

Abstract
This paper describes an experimental effort to identify and document the turbulent flow, induced surface pressures, and structural response of a hydrofoil at chord-based Reynolds numbers up to 60 million. Special interest is focused on the trailing edge of the foil where most of the measurements are made. The experiments are conducted at the US Navy’s W. B. Morgan Large Cavitation Channel with a two-dimensional test-section-spanning hydrofoil (2.1 m chord, 3.0 m span) at flow speeds from 0.5 to 18.3 m/s. The foil section is a modified NACA 16 with a flat pressure side. The measurements presented in this paper include foil surface static and dynamic pressures, foil vibration, LDV-determined average flow speeds and turbulence quantities, and PIV flow fields in the immediate vicinity of the foil’s trailing edge.
A Transmission Line Approach to the Acoustic Analysis of Piping Systems
Authors: Stokes Ann , Conti Matt , Corrado Charles , Arzoumanian Sevag 
Published: November 2021

Abstract
We present a wave transmission line model developed to understand the transmission of energy through fluid-filled piping systems. The piping systems are represented as a sequence of components, e.g. valves, bends, and other components, connected with straight pipe sections. The transmission line model makes use of experimentally- or analytically-determined scattering coefficients to represent component behavior. The coefficients capture important coupling between fluid and structure, and among different structural wave types. The measurement of these coefficients is the subject of a separate paper [1]. The straight pipe segments are modeled analytically using fluid-filled, thick shell theory. Their motion is described in terms of amplitudes of freely traveling, left-and-right propagating waves.
Results are presented which compare transfer functions measured on a piping system to predictions from the transmission line model, where each component is modeled with experimentally determined scattering coefficients. Initial results highlight important issues regarding the use of reciprocity, passivity, and causality to improve the quality of coefficients which are difficult to measure (for example, where certain frequency bands had high signal to noise). Algorithms for determining whether measured coefficients meet constraints on passivity, reciprocity, and causality are introduced. Predictions comparing analytical and measured coefficients are shown for a single-component (elbow) piping system.
Damping Loss Factor Estimation for Test-Based Vehicle SEA Modeling
Authors: Woo Jae-Hak , Zeng Xiandi 
Published: November 2021

Abstract
In the test-based SEA models, the major parameters are measured or estimated from measured quantities. One of the parameters is Damping Loss Factor (DLF) of the air (passenger) cavity of a vehicle. In the SEA model, the air cavity is divided into several sub-cavities. The required DLF for each sub-cavity can be calculated from the reverberation time (T60) measured in that sub-cavity in the vehicle. However, if nothing is done to separate one sub-cavity from other sub-cavities in the T60 measurement in the vehicle, the measured T60 for that sub-cavity is the T60 of the whole air cavity. When the resulted DLF is used in SEA model of that sub-cavity, it is the DLF of the whole air cavity that is used for a sub-cavity, which will result in an over/under-damped. Thus, the prediction from such a SEA model will have bias error especially in the higher frequency range. This has been seen in the results of a vehicle SEA model. In this paper, a method is proposed to estimate the DLF of each sub-cavity based on the T60 of the whole air cavity. When these estimated DLF’s are used in the SEA model for each sub-cavity, the correlation in SEA model was improved by 2.5∼3 dB above 1kHz.
Identification of Incoherent Noise Sources
Authors: Raveendra S. T. , Sureshkumar S. 
Published: November 2021

Abstract
A Nearfield Acoustical Holography (NAH) technique that is applicable to the identification of multiple, incoherent noise sources from measured sound pressure fields are described. Initially, a partial coherence approach is adopted to decouple an incoherent acoustic field into a set of fully coherent, mutually incoherent partial fields. Subsequently, NAH is applied individually to each coherent partial field to reconstruct the corresponding source field. A boundary element based NAH reconstruction procedure is utilized so that the technique is valid for arbitrary source geometry. The process is validated by identifying the sources in a two-speaker system that was driven by independent signal generators.
A Computational Process for Pass-by Noise Simulation
Authors: Zhang Zhidong , Vlahopoulos Nickolas , Allen T. , Zhang K. Y. 
Published: November 2021

Abstract
The Indirect Boundary Element Analysis is employed for developing a computational pass-by noise simulation capability. An acoustic field reconstruction process is developed in order to generate the definition of the main pass-by noise sources in a numerical model. Numerical boundary element models that characterize the individual sources are combined with a vehicle model for developing a system model for pass-by noise simulation. The numerical algorithm for defining generic sources is validated initially by employing analytical solutions. The numerical techniques are also validated through comparison between numerical results and test data for component level and system level analyses. Specifically, the generic source definition capability is validated by comparing the actual and the computationally reconstructed acoustic field for an engine intake manifold. The overall pass-by noise simulation capability is validated by computing the maximum overall sound pressure level for a vehicle under two different driving conditions.
Introduction to Thermoacoustic Engines and Refrigerators
Authors: Poese Matthew E. , Garrett Steven L. 
Published: November 2021

Abstract
Glassblowers observed the generation of sound in the presence of temperature gradients over one hundred years ago. It was less than twenty years ago that the reverse process — the use of high-amplitude sound to produce refrigeration — was first demonstrated. Due to the discovery of the “hole-in-the-ozone” and the ratification of the Montreal Protocols, research in thermoacoustics has accelerated during the past decade. In 1992, an electrically powered thermoacoustic refrigerator was placed in orbit on the Space Shuttle and a larger thermoacoustic chiller for shipboard electronics was operated to cool radar equipment for a week on board a US Navy destroyer in 1995. More recently, a heat-driven thermoacoustic device, built by the team at Los Alamos, was used to liquefy natural gas at a rate in excess of 140 gal/day by burning part of the gas stream.
A Multiple-Frequency Partial-Field Method for Exterior Acoustics Based on Padé via Lanczos Approximants
Authors: Wagner Marcus M. , Pinsky Peter M. , Malhotra Manish 
Published: November 2021

Abstract
A solution methodology is introduced for the efficient computation of the acoustic field over restricted domains and for a frequency window. Typically, such partial field solutions include, for example, surfaces enclosing the radiating structure or even single points in the computational domain. The multiple-frequency partial-field (MFPF) method starts out by reformulating the finite element matrix system into a suitable shifted form. The DtN map is used as a radiation boundary condition and is interpreted as a low rank update of the matrix problem. The shifted standard form is then approximated by a rational matrix-valued Padé approximant and solved simultaneously over a frequency range. To obtain the Padé approximation, a banded unsymmetric Lanczos process is applied on the standard shifted form exploiting the matrix Padé-via-Lanczos connection. Numerical examples show the feasibility of the outlined procedure.
Computation of Time Harmonic Acoustic Waves in a Duct With Nonuniform Mean Flow
Authors: Ali Amr A. , Atassi Oliver V. , Atassi Hafiz M. 
Published: November 2021

Abstract
The propagation of time-harmonic acoustic and vortical waves in a nonuniform swirling mean flow is studied. A second order accurate numerical scheme is used in solving the linearized Euler equations for an annular duct geometry. A three dimensional ‘exact’ nonreflecting boundary condition is applied downstream of the truncated duct. The numerical issues of implementing the nonreflecting boundary conditions are investigated. Solutions are presented for uniform and nonuniform swirling flows and compared with analytical solutions for validation. The computational results are in good agreement with the theory.
Decentralized Control of Structural Acoustic Radiation
Authors: Frampton Kenneth D. 
Published: November 2021

Abstract
Although the application of active control to vibrations has been investigated from many years, the extension of this technology to large-scale systems has been thwarted, in part, by an overwhelming need for computational effort, data transmission and electrical power. This need has been overwhelming in the sense that the potential applications are unable to bear the power, weight and complex communications requirement of large-scale centralized control systems. Recent developments in MEMS devices and networked embedded devices have changed the focus of such applications from centralized control architectures to decentralized ones. A decentralized control system is one that consists of many autonomous, or semi-autonomous, localized controllers called nodes, acting on a single plant, in order to achieve a global control objective. Each of these nodes has the following capabilities and assets: 1) a relatively limited computational capability including limited memory, 2) oversight of a suite of sensors and actuators and 3) a communications link (either wired or wireless) with neighboring or regional nodes. The objective of a decentralized controller is the same as for a centralized control system: to maintain some desirable global system behavior in the presences of disturbances. However, decentralized controllers do so with each node possessing only a limited amount of information on the global systems response. Exactly what information each node has access to, and how that information is used, is the topic of this investigation.
Analysis of a Biological Ultrasonic Sensory System
Authors: Danak A. D. , Hastings M. C. 
Published: November 2021

Abstract
A mathematical model is developed to examine the ability of American shad to detect ultrasound. The preliminary model is integral in obtaining a thorough understanding of the impact of the swimbladder and unique structures in the inner ear of the American shad on auditory sensitivity. Behavioral studies have already shown that a few fish species, including American shad (Alosa sapidissima) can detect ultrasonic frequencies up to 200 kHz (Dunning et.al., 1992; Nestler, Ploskey, and Pickery, 1992; Mann, Lu, and Popper, 1997; Mann, et. al 1998; Popper et.al, 1999). Although the auditory mechanisms involved are yet to be determined, all evidence obtained from this initial model suggests that the inner ear and auditory processing system play a key role. Once fully completed, such a model can be used to initiate development of a man-made sensor with similar capabilities of the shad ear for use in vivo clinical procedures using ultrasound.
Ladder Rung vs. Siderail Hand Grip Strategies
Authors: Barnett Ralph L. , Poczynok Peter J. 
Published: November 2021

Abstract
When climbers lose their foothold on fixed, straight or extension ladders, the incipient fall may be arrested by gripping either the ladder rungs or siderails. Grasping the rungs provides an interference or power grip; squeezing the siderails provides a friction grip which is the primary focus of this paper. The falling scenario begins with free fall that lasts for the duration of the simple reaction time. Free fall is then decelerated by contravening friction forces derived from hand grip forces rapidly applied to the siderails. Using hand grip/time histories for various individuals, their fall distances were calculated for bare and gloved hands on a vertical steel fixed ladder. Sometimes the candidates could not arrest their falls; often their fall distance was too great to prevent ground impact. Under some circumstances, the vertical motion was brought under timely control. Although a rich literature is available for characterizing grip strength, data reflecting grip/time profiles does not appear. Grip strength/time diagrams were measured for fourteen test subjects.
The Machine Operator’s Jammed-Feedstock-Clearing Task: A Safety Design Challenge
Authors: Etherton J. R. , McKenzie E. A. 
Published: November 2021

Abstract
Workers are often exposed to injury risk from sudden and unexpected machine movement when clearing jammed material from process machinery. An engineered safety response can effectively intervene to control or eliminate this risk. Backstrom and Doos (1998) found that about 25% of injuries involving automated machinery were preceded by a disturbance in process material flow such as a piece of material becoming stuck, crooked or getting in an otherwise faulty position. In the US, lockout is required when an employee is required to place any part of his or her body into an area on a machine or piece of equipment where work is actually performed upon the material being processed (point of operation) or where an associated danger zone exists during a machine operating cycle. Minor tool changes and adjustments, and other minor servicing activities, which take place during normal production operations, are not covered by the OSHA lockout standard if they are routine, repetitive, and integral to the use of the equipment for production, provided that the work is performed using alternative measures which provide effective protection [emphasis added] (OSHA, 1989). Machine control systems that can automatically detect and respond to hazardous operating conditions could be a way to reduce machine-related injury and fatality rates. Accurate laboratory testing criteria, based on key patterns manifested by the machine during hazardous events are vital to developing such new safety technology. This paper discusses safety design challenges in designing reliable safeguarding associated with machinery.
International Safety Alert Symbol
Authors: Barnett Ralph L. , Wambaja Raymond 
Published: November 2021

Abstract
With the adoption of the international safety alert symbol, the safety profession has lost an important weapon in the war against injury. The symbol is not uniquely associated with safety, it does not have an optimum shape and it has no intrinsic pictorial to communicate danger to untrained people from every culture. The symbol represents a tragic “missed opportunity” for mobilizing personal vigilance.
Robust Designs, Utilizing Six-Sigma Quality Processes, Linked to a USMC Weapon System
Authors: Strifas Nick , Kalamajka Bob , Ruzzene Massimo 
Published: November 2021

Abstract
This study describes the approach to integrate Six-sigma and Robust Design approaches on a US Marine Corps (USMC) program. Six Sigma and Robust Design techniques are tightly coupled to ensure that a design is both manufacturable and also serves the needs of the US Marines. Six Sigma is an aggressive (stretch) goal that sets a high standard of excellence for the development of a world class quality product (Short Range Anti-tank Weapon - SRAW) for the US Marines. This study also describes how the design team is linking Six Sigma and Robust Design, to ensure that a very complex product, with many steps and processes involved in its manufacture, can be recognized as a superior one.
Friction-Related Aspects of Human Pushing
Authors: Pattin Cheryl A. , Barnett Ralph L. 
Published: November 2021

Abstract
Human pushing capability affects performance in the areas of crowd and animal control, the security of locked doors and railings, the removal of tree stumps and entrenched vehicles, the maneuvering of furniture, and in athletic pursuits such as football or wrestling. Pushing capability is a function of both individual characteristics (e.g., muscular strength, body weight, and the distribution of that weight) and attributes of the pushing task itself (e.g., footwear/floor and torso/object friction). Mathematical relationships among these factors are developed. Using these relationships, the maximum push that can be generated without slip were calculated for the following two conditions: (1) LEAN only, with the torso about to slip down the pushed object and feet about to slip along the floor and (2) PUSH along the body contact line with the torso about to slip up the pushed object and the feet about to slip along the floor.
The Explosion of a Fireworks Storage Facility and its Causes
Authors: Ale B. J. M. 
Published: November 2021

Abstract
On 13 may 2000 an explosion occurred in a fireworks storage and trading facility in Enschede, the Netherlands. Twenty-two people were killed and some 900 injured. The material damage was approximately 400 MEuro.
Immediately after the accident an investigation was started into the causes of the accident. Special attention was given to the unexpected violence of the explosion. The investigative committee installed by the Government used results and advice of domestic and international institutes to obtain results.
It appeared that the firm had a long history of violating permits, that the city had legalised these violations and that inspectorates and state institutions were not aware of the hazards thus created. Especially the importance of the correct classification of the fireworks and of the storage of the correct types and quantities went unnoticed. As a result prior to May 13 2000 most of the fireworks stored at the premises were more powerful than the labels indicated and in fact a significant part of the storage was mass-explosive contrary to the current permit.
Risk Analysis of the Storage Facility of S.E. Fireworks in Enschede, the Netherlands
Authors: de Haag P. A. M. Uijt , Laheij G. M. H. , Ale B. J. M. 
Published: November 2021

Abstract
In the course of the investigation into an explosion in a fireworks storage facility in the Netherlands risk analyses were performed on the facility as it should have been under the current legislation and permits and as it actually was. The results show that under the current legislation the facility was acceptable in its present location, if it adhered to the terms of its permit. However as it actually was it was completely unacceptable.
The results are compared with the results of analyses of industrial facilities and other hazardous activities to place the risk of storage of pyrotechnics in the context of other industrial risk.