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Acentech Incorporated

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Zapfe J.A.,Acentech Incorporated | Moore J.A.,Acentech Incorporated
Journal of the Acoustical Society of America | Year: 2012

Point force impedance expressions have been previously developed for infinite Kirchhoff and Mindlin plates. The present work develops impedance expressions for the more general case of an infinite plate with a circular, massless, rigid plug using both Kirchhoff and Mindlin plate theories. The models have been developed to analyze vibration propagation in buildings. The plate with the rigid plug provides a more reasonable model of the kinematic constraint at the column/floor interface. The models are used to investigate the potential benefits of using thick floors to block the transmission of structure-borne vibration in buildings. © 2012 Acoustical Society of America.


Bowen D.L.,Acentech Incorporated
Sound and Vibration | Year: 2010

This article describes methods that were used for evaluating and designing sound quality improvements on a front-loading washing machine where the primary goals were to evaluate sound quality as determined by actual users and to measure the impact and value of various possible sound modification scenarios. These goals were accomplished in part by convening jury studies where jurors rated the sounds of various "virtual" and existing washing machines to identify and quantify how various components and mechanisms that operate within each cycle/mode of the washer affected consumer perceptions of sound quality expressed in terms of their ratings on the attributes "acceptability" and "overall impression.".


Fullerton J.L.,Acentech Incorporated
INTERNOISE 2014 - 43rd International Congress on Noise Control Engineering: Improving the World Through Noise Control | Year: 2014

Geothermal heat pumps are an energy efficient option for many residences as an alternative to more conventional gas or oil fueled residential HVAC systems. This paper continues discussions about the noise and vibration issues from these residential geothermal systems that have been presented in prior papers by this author. In this paper, the noise contributions of two components of the ground water system will be discussed. First, the paper will discuss the influence of noise from the control system that regulates the ground water flow. A comparison of the noises from a simple pressure switch system versus a variable speed controller will be discussed. Second, the ground water system includes zone control valves to manage the water flow for the different systems. These valves can contribute to the noise generated by the system when it operates. Two types of valves will be discussed, which have dramatically different designs and different sound emissions. The paper concludes with recommendations for achieving a low noise ground water system to serve the geothermal heat pumps.


Barnes J.D.,Acentech Incorporated | Wood E.J.W.,Acentech Incorporated
41st International Congress and Exposition on Noise Control Engineering 2012, INTER-NOISE 2012 | Year: 2012

Mentors. They share insights and wisdom while offering their support and guidance to others. They often help younger colleagues and friends in their advancement as they grow to become outstanding professionals. This paper identifies some noteworthy mentors we have had the pleasure of learning from and relates experiences we have had working with them during more than15 years as acoustical consultants at Bolt Beranek and Newman, and most recently during 23 years as senior staff at the acoustical consulting firm Acentech Incorporated. Our mentors have helped to improve our technical and problem solving skills as well as our written and verbal communication skills. From mentors, we have learned what sets the excellent consultant apart from the not-so-excellent consultant. Mentors, they contribute greatly to the future of our profession.


Davenny B.,Acentech Incorporated
41st International Congress and Exposition on Noise Control Engineering 2012, INTER-NOISE 2012 | Year: 2012

Speech privacy is addressed in the 2010 Guidelines for Design and Construction of Health Care Facilities, which references the ASTM test standards E1130 for open plan and E2638 for closed rooms1-3. Both standards use noise reduction and background sound measurements, but the test methods are limited to the domain of each standard. ASTM E1130 has no guidance for performing tests to calculate the privacy index between two closed rooms. Similarly, ASTM E2638 has no guidance for performing tests to calculate the speech privacy class in open plan areas. This paper will present results from measurements at an outpatient facility where noise reduction was measured according to the ASTM E2638 standard and both privacy index and speech privacy class were calculated. Assumptions made to calculate the privacy index for closed rooms will be discussed.


Barnes J.D.,Acentech Incorporated | Unger G.L.,Acentech Incorporated
41st International Congress and Exposition on Noise Control Engineering 2012, INTER-NOISE 2012 | Year: 2012

Sound monitoring can be a powerful tool for testing project compliance and investigating community noise complaints. The monitoring program may be as simple as a one-time (one and done) nighttime survey in order to demonstrate compliance with project sound limits at representative community locations. And it may be as complex as long-term continuous measurement of overall A-weighted and spectral sound levels, which may be supplemented by sound recordings and community resident complaint logs to characterize the noise disturbance and associated conditions, in order to identify the potential noise source(s). This paper describes a variety of actual monitoring programs and highlights their goals, challenges, benefits, and limitations in addressing community noise problems. In addition, it opines on the future design of sound monitoring programs as they incorporate new instrumentation and survey methods.


Grant
Agency: Department of Defense | Branch: Defense Health Program | Program: SBIR | Phase: Phase I | Award Amount: 149.23K | Year: 2012

Tinnitus, along with hearing loss, are the two top service-related disabilities for veterans. It has been estimated that together the cost to the Veterans Administration is $1.5B annually. While hearing loss can readily be quantified, measures of tinnitus have remained highly subjective making quantitive assessments of occurrence and severity difficult. This project seeks to develop a quantitative measure of tinnitus based on the Tracking Task Procedure (TTP) based on the well-recognized observation that individuals with tinnitus have difficulty identifying a continuous tone presented in the frequency regime of their tinnitus. Protocols and methods will be developed, coded in software and incorporated in a prototype device that will be ready for clinical trials in Phase II. The ultimate goal is the development of an easy to use, inexpensive system to provide military clinicians the quantitative information they need to care for and rehabilitate tinnitus patients.


Grant
Agency: Department of Defense | Branch: Navy | Program: SBIR | Phase: Phase II | Award Amount: 749.82K | Year: 2010

The goal of this Phase II will be a full scale demonstration of an acoustic metamaterial cloak on a UUV-like vehicle. The design will be based on the Cummer-Schurig cylindrical solution for a perfect 2-D cloak surrounding a rigid cylindrical object. The first effort will be a theoretical task in conjunction with KSU to evaluate important issues related to the abstract nature of the Cummer-Schurig solution, which calls for infinite mass density and stiffness boundary conditions and purely real dynamic quantities (i.e., no losses). The type of resonant dynamical element to be used in the design to create the anisotropic mass densities required will be selected. Two major candidates identified in Phase I are resonant masses requiring voids encapsulated by high rigidity structures (e.g. shells) and a system of shaped inclusions embedded directly in an elastomer matrix. Laboratory experiments guided by co-evolving analytical and numerical models will be performed to demonstrate the required dynamical behavior for each treatment layer, to be followed by fabrication and testing larger cloak layer samples to assure that properties are maintained with scale up. Finally, a full scale demonstration will be conducted with a suitable vehicle or stand-in structure.


Grant
Agency: Department of Defense | Branch: Navy | Program: SBIR | Phase: Phase I | Award Amount: 79.93K | Year: 2011

Acentech proposes to develop an underwater sound projector source that can be used for Low Frequency Long Range Acoustic Communications, and which is operational down to a depth of 1000 m. This transducer design incorporates new high output magnetostrictive materials that are robust, malleable and machinable, and which are arranged in ring fashion along with an innovative displacement amplification system employing curved lamina. Preliminary modeling and analysis of this new transducer indicate output levels substantially in excess of those required are achievable at and above 100 Hz in water, with relatively low voltage drive levels. Furthermore, due to the non-resonant nature of its design, there is a nearly linear response in both the magitude and phase of the output within its target frequency range. This Phase I proposal describes our approach to achieving the desired design by structural and equivalent circuit analysis, parameter optimization, as well as by consultations with industry partners in the materials, fabrication and manufacturing space. The results we obtain from Phase I will prepare us for the analysis, building and testing of a functional prototype transducer in Phase II.


PubMed | Acentech Incorporated
Type: Journal Article | Journal: The Journal of the Acoustical Society of America | Year: 2012

Point force impedance expressions have been previously developed for infinite Kirchhoff and Mindlin plates. The present work develops impedance expressions for the more general case of an infinite plate with a circular, massless, rigid plug using both Kirchhoff and Mindlin plate theories. The models have been developed to analyze vibration propagation in buildings. The plate with the rigid plug provides a more reasonable model of the kinematic constraint at the column/floor interface. The models are used to investigate the potential benefits of using thick floors to block the transmission of structure-borne vibration in buildings.

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