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Cambridge, MA, United States

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

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. Source

Bowen D.L.,Acentech Incorporated
Sound and Vibration

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.". Source

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

Zapfe J.A.,Acentech Incorporated | Saurenman H.,ATS Consulting | Fidell S.,Fidell Associates Inc.
Notes on Numerical Fluid Mechanics and Multidisciplinary Design

Ground vibration produced by rail transit systems can be annoying to nearby building occupants when they perceive some combination of feelable vibration, re-radiated sound, and vibration-induced rattling of household paraphernalia. Community response to rail-induced ground vibration has not been extensively researched. While the well-known Schultz dosage - response curve is routinely used to predict the prevalence of annoyance produced by airborne transportation noise, no similar relationship has gained widespread acceptance for groundborne noise and vibration. The principal goal of the present study was to develop a dosage response relationship for predicting community annoyance due to ground vibration produced by rail transit systems. The research was conducted as part of the Transit Cooperative Research Program D-12 project. Telephone interviews were conducted with 1306 individuals in five North American cities. Field measurements were made in each city to estimate vibration and noise exposure at each interview location. The work produced several dosage - response relationships between vibration/noise exposure and annoyance. When compared to the current noise and vibration criteria specified by the United States Federal Transit Administration (FTA), the dosage response analysis predicted a probability of 0.05 to 0.10 that a D-12 respondent would be highly annoyed by vibration and noise at the current FTA criterion levels. © 2012 Springer. Source

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.

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