| Acoustic Absorption Measurements for Characterization of Gas Mixing |
14 MAY 2003 |
10 pages |
| Authors:
Aurelien Cottet; Lei Wu; Andrew Meyers; David Scarborough; Tim Lieuwen; GEORGIA INST OF TECH ATLANTA
|
 | This paper demonstrates the use of acoustic absorption measurements to characterize the level of molecular mixing between gaseous mixtures. This objective is motivated by the observation that many existing methods only quantify macro-scale entrainment. Over a large range of frequencies, acoustic damping is dominated by vibrational relaxation processes. Our approach takes advantage of the fact that the relaxation frequency for a particular gas is often a strong function of the ... |
|
| SIS Receiver Noise Stability |
29 SEP 2000 |
4 pages |
| Authors:
RJ. W. Kooi; G. Chattopadhyay; M. Thielman; T. G. Phillips; R. Schieder; CALIFORNIA INST OF TECH PASADENA
|
| There is a strong interest in the submillimeter astronomy community to increase the IF bandwidth of SIS receivers in order to better facilitate broad spectral linewidth and continuum observations of extragalactic sources. However, with an increase in receiver IF bandwidth there is a decrease in the mixer stability. This in turn effects the integration efficiency and quality of the measurement. In order to better understand the noise mechanisms responsible for ... |
|
| Acoustic Transducer Panel |
07 SEP 1999 |
17 pages |
| Authors:
Thomas R. Howarth; DEPARTMENT OF THE NAVY WASHINGTON DC
|
| An electro-acoustic transducer in which a plurality of cymbal-type electro-acoustic actuators are disposed in mechanical and electrical parallel between a pair of stiff plates. The resultant transducer resonates at a lower frequency than the cymbals, with a greater generated force. |
|
| Artificial Heads for High-Level Impulse Sound Measurement |
1999 |
8 pages |
| Authors:
K. Buck; G. Parmentier; INSTITUT FRANCO-ALLEMAND DE RECHERCHES SAINT-LOUIS (FRANCE)
|
| If the Insertion Loss (IL) of hearing protectors has to be determined with very high impulse or continuous noise levels, the acoustic insulation of the Artificial Test Fixture has to exceed at least the Insertion Loss (IL) of the hearing protector. An another requirement when evaluating ear muffs, is an adequate reproduction of the pinna and the circumaural area. For the evaluation of ear plugs and ... |
|
| Development of a Muffler for Small Arms Range Noise Mitigation |
SEP 1998 |
51 pages |
| Authors:
Larry Pater; Anthony Krempin; CONSTRUCTION ENGINEERING RESEARCH LAB (ARMY) CHAMPAIGN IL
|
| Small arms fire can result in noise complaints from nearby residents. The objective of the project reported herein was to provide a mitigation strategy to reduce small arms noise impact in the neighborhood of Camp Dodge, IA. The selected strategy was a low cost muzzle blast muffler. The U.S. Army Construction Engineering Research Laboratories (USACERL) designed, constructed, and tested several variations of mufflers. The basic design consists of a tube ... |
|
| Vibrationally Damped Structure |
06 JAN 1998 |
|
| Authors:
Jeffrey S. Hanson; DEPARTMENT OF THE NAVY WASHINGTON DC
|
 | A vibrationally damped structure includes a structure that is susceptible to vibrations and a constrained damping layer positioned over at least a portion of the vibrating structure. The constrained damping layer includes a continuous damping layer bonded to the surface of the structure for providing the first reduction of vibrational energy transmitted through the structure. The constrained damping layer further includes a segmented constraining layer bonded to a portion of ... |
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| Microwave Nondestructive Evaluation of Disbonds Under Anechoic Tiles |
JUL 96 |
|
| Authors:
R. J. Ditchburn; A. Amiet; S. K. Burke; DEFENCE SCIENCE AND TECHNOLOGY ORGANIZATION CANBERRA (AUSTRALIA)
|
| An experimental and theoretical study of a microwave nondestructive inspection technique to detect the presence of and evaluate the thickness of disbonds between anechoic tiles and the hull of the COLLINS class submarine is presented. The magnitude and phase of a reflected microwave signal in the absence and presence of a disbond is measured as a function of disbond thickness and frequency for (i) a layer of anechoic tile material ... |
|
| New Technology for Controlling NOx from Jet Engine Test Cells. Phase 1 |
JAN 95 |
47 pages |
| Authors:
Richard K. Lyon; ENERGY AND ENVIRONMENTAL RESEARCH OF NJ WHITEHOUSE WHITEHOUSE LAB
|
| For some time the U.S. Air Force has been concerned with NOx emissions from jet engine test cells operated by the Air Force. While there are no regulations limiting the NOx emissions of these facilities, such regulations could develop in the near future and would pose significant problems for the Air Force because no available technology is suited for application to jet engine test cells. This report describes laboratory studies ... |
|
| Symposium on Amorphous Insulators |
11 AUG 94 |
234 pages |
| Authors:
Robert G. Leisure; COLORADO STATE UNIV FORT COLLINS DEPT OF PHYSICS
|
| (MM) |
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| Noise Level Reduction of .50 Caliber Gunfire by Terrain Shielding |
JUL 94 |
66 pages |
| Authors:
Larry L. Pater; Raman Yousefi; Walter Alvendia; CONSTRUCTION ENGINEERING RESEARCH LAB (ARMY) CHAMPAIGN IL
|
| Gunfire at Army rifle ranges is an unavoidable part of military training that can disturb the surrounding community and become a source of complaint. Barriers can effectively screen noise in some scenarios, and are useful in reducing noise from small arms fire because acoustic energy from this noise source is concentrated at relatively high frequencies, making barriers of modest size large in terms of wavelength and capable of providing significant ... |
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| Submarine Hull Structures Providing Acoustically Isolated Hull Openings. |
30 JUN 1994 |
|
| Authors:
Paul E. Moody; DEPARTMENT OF THE NAVY WASHINGTON DC
|
| An acoustic isolation structure providing an acoustically isolated opening and comprising coaxial inner and outer annular structural members defining an irregular annulus between them. Acoustical isolation material is provided within this annulus to acoustically uncouple the two members. Radially overlapping structural rings extending from the members into the annulus limit lateral movement of the inner member and preserve the generally coaxial relation of the members. |
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| Benefit/Cost Analysis of Interdwelling Noise Control in Multifamily Dwellings |
DEC 91 |
111 pages |
| Authors:
Paul K. Augustine; W. D. Rowlands; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| This thesis was undertaken to perform a benefit/cost analysis of interdwelling noise control in multifamily dwellings. Specifically, the benefit/ cost analysis was performed to determine whether multifamily dwelling owners would find it economically beneficial to provide multifamily dwellings that are insulated from interdwelling noise. In other words, does the marginal benefit to the owner (additional monthly rent) exceed the marginal cost of providing the added insulation? A questionnaire was used ... |
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| Studies of Optical Beam Phase-Conjugation and Electromagnetic Scattering Process |
06 MAR 91 |
|
| Authors:
Robert W. Hellwarth; UNIVERSITY OF SOUTHERN CALIFORNIA LOS ANGELES
|
| This project performed both experimental and theoretical studies of optical beam phase-conjugation and of electromagnetic scattering and propagation with intense optical fields. We have: (1) made the first determination of the nonlinear optical index of air and of common gases throughout the visible; (2) established the threshold beam intensities required to produce nonlinear effects in plasma; (3) measured the linear and nonlinear refractive indices of many new optical polymers; (4) ... |
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| Considerations in the Design and Development of a Human Computer Interaction Laboratory |
20 SEP 90 |
24 pages |
| Authors:
Lisa B. Achille; NAVAL RESEARCH LAB WASHINGTON DC
|
| The author outlines the design and development of a Human Computer Interaction Laboratory; discusses preparatory system design stages; defines operational requirements; identifies laboratory functions; addresses architectural and environmental features (such as lighting, soundproofing, and electrical service) as they relate to the special needs of a research facility; evaluates equipment subsystems (particularly audiovisual recording systems), and presents equipment lists and a design considerations checklist. (kr) |
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| Low-Sidelobe Phased Array Antenna Characteristics Using the Planar Near- Field ScAnning Technique: Theory and Experiment |
14 FEB 90 |
|
| Authors:
A. J. Fenn; H. M. Aumann; F. G. Willwerth; MASSACHUSETTS INST OF TECH LEXINGTON LINCOLN LAB
|
| Characteristics of a low-sidelobe phased array antenna are investigated using the technique of planar near-field scanning. The theory associated with the planar near-field scanning technique, with and without probe compensation, is reviewed and an application of the theory is made. The design of an experimental low-sidelobe phased array antenna consisting of monopole elements which are corporate-fed using high precision transmit/receive modules is described. Accurate array radiation patterns are obtained both ... |
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| Low Loss Electro-Optic Modulator Mount. |
18 JUL 1989 |
|
| Authors:
Ronald E. Belek; Robert J. Mongeon; Lanny M. Laughman; DEPARTMENT OF THE AIR FORCE WASHINGTON DC
|
| The crystal is solid CdTe or GaAs for modulating a laser beam. The mount comprises Al2O3 or BeO ceramic between the crystal and a U-shaped aluminum housing on three sides to provide low stray capacitance and high thermal conductivity to the cooled housing. A layer of lead between the ceramic and the housing enhances the acoustic damping of the structure. Electrodes are attached to the crystal, with lead used to ... |
|
| Fibrous Glass Aerosols: A Literature Review |
02 OCT 1987 |
20 pages |
| Authors:
Bruce R. Laverty; NAVAL SUBMARINE MEDICAL RESEARCH LAB GROTON CT
|
| The submarine atmospheric is a topic of interest, considering that once submerged, the craft relies on its own electrostatic precipitators (ESP's), scrubbers, and filters to create, ideally, an environment with minimal aerosolized toxic materials and other by-products. Historically, atmosphere sampling aboard nuclear submarines has shown contaminants. Other contaminants include: ozone, (major source: by-product of the ESP's); Freon, (major source: ship's refrigeration system and air conditioning plants); hydrogen, (major source: ship's ... |
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| Fabrication and Parachute Career Ladder, AFSC 427X3 |
AUG 87 |
|
| Authors:
AIR FORCE OCCUPATIONAL MEASUREMENT CENTER RANDOLPH AFB TX
|
| This occupational survey report addresses the Fabrication and Parachute career ladder (AFSC 427X3). The Training Development Services Division of the USAF Occupational Measurement Center (USAFOMC/OMT) requested this study to determine field training needs and to gather data for validating the Specialty Training Standard (STS). AFSC 427X3 was last surveyed in December 1980. The present AFSC 427X3 career ladder emerged from the merger of the Parachute Rigger career ladder (AFSC 582X1) ... |
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| The Smoke Hazards Resulting from the Burning of Shipboard Materials Used by the U.S. Navy. Part 2 |
01 OCT 86 |
|
| Authors:
F. W. Williams; B. T. Zinn; R. F. Browner; E. A. Powell; NAVAL RESEARCH LAB WASHINGTON DC
|
| Physical and chemical properties of smoke particulates generated during combustion were determined for a polyphosphazene foam being considered for use as a thermal and acoustic insulation material in submarines. Study results indicate that during nonflaming combustion this polyphosphazene foam produces smoke particles with a log-normal size distribution and a mean diameter of approx. 0.45 microns; during flaming combustion, it produced black smoke consisting of nonspherical soot aggregates with a mean ... |
|
| Energy Absorption of Polyurethane Based Poloymer Alloys |
15 SEP 86 |
|
| Authors:
Irfan Raza; Bhavesh Muni; Bijan Sedghi; Kurt C. Klempner; Daniel Frisch; DETROIT UNIV MI POLYMER INST
|
| Interpenetrating polymer networks (IPNs) elastomers and foams composed of polyurethanes and epoxies were prepared by the simultaneous technique. Fillers and plasticizers were incorporated by random batch mixing. The PU/epoxy ratio was varied. Enhanced energy absorbing abilities were demonstrated by the dynamic mechanical spectroscopy results (broad and high tan delta behavior as a function of temperature). This was reflected in the mechanical and acoustical energy absorption of the foams. The effects ... |
|
| Effect of Sealants of the Sound Absorption Coefficients of Acoustical Friable Insulating Materials |
OCT 1984 |
|
| Authors:
J. L. Wayman; M. K. Lory; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| Acoustical friable insulating materials (AFIM), which often in the past contained asbestos, have been used for sound control since the mid 1930's. Because of their widespread use and the ease of fiber dissemination, friable asbestos materials are considered to be the major source of asbestos fiber contamination in the indoor environment. Encapsulation of asbestos materials with a commercial sealant product is one of several methods used to control potential asbestos ... |
|
| Use of Aqueous Foam to Mitigate Demolitions Noise |
DEC 1981 |
42 pages |
| Authors:
Richard Raspet; CONSTRUCTION ENGINEERING RESEARCH LAB (ARMY) CHAMPAIGN IL
|
| This report describes an investigation into whether aqueous foam is a viable technique for quieting unconfined explosives and whether design parameters can be established for its use to reduce the environmental noise levels of Army artillery, demolition, and explosives ordnance disposal. It was concluded that: (1) Both high- and low-expansion ratio foams can be used to reduce the blast noise levels of Army explosive charges. For unconfined explosives, it was ... |
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| The Determination of the Smoke Hazards Resulting from the Burning of Shipboard Materials Utilized by the US Navy |
31 AUG 1981 |
|
| Authors:
GEORGIA INST OF TECH ATLANTA
|
| In further investigations of shipboard fires, physical and chemical properties of smoke particulates generated during combustion were determined for a polyphosphazene foam being considered for use as a thermal and acoustic insulation material in submarines. Physical properties measured were particle size distribution and mean particle diameter, mass fraction of fuel converted to particulates, optical density, particle refractive index, and particulate volume fraction. Dependence of these properties on the temperature of ... |
|
| Noise Control: Pile Driver Demonstration Project, Waterloo, Iowa |
JUL 1981 |
|
| Authors:
Fred M. Kessler; Paul D. Schomer; DAMES AND MOORE CRANFORD NJ
|
| A project jointly sponsored by the Environmental Protection Agency (EPA), Office of Noise Abatement and Control; the U.S. Army Corps of Engineers, Construction Engineering Research Laboratory (CERL); and the Directorate of Civil Works was undertaken to demonstrate in a construction project the availability of retrofit control technology for pile drivers. Various in-use retrofit noise control measures for reducing the noise of pile drivers were investigated: alternative pile driving techniques, mufflers, ... |
|
| The Aging of Cork-Rubber Decoupling Materials. |
09 MAR 1981 |
|
| Authors:
L. E. Horsley; C. M. Thompson; NAVAL RESEARCH LAB WASHINGTON DC
|
| Pressure-release materials are used to insulate come components of sonar transducers. By acoustically shielding some areas of the transducer, the directivity and sensitivity can be greatly altered. Pressure-release materials/insulate because of their large differences in acoustic impedance from that of the other components and fluids used in transducers. One serious problem is that these pressure-release materials absorb the transducer fill fluids. This increase the acoustic impedance and therefore reduces the ... |
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| Management Procedure for Assessment of Friable Asbestos Insulating Materials. |
FEB 1981 |
|
| Authors:
Ernest E. Lory; Denise S. Coin; Kenneth S. Cohen; James S. Dyer; Magnus J. Hienzsch; CIVIL ENGINEERING LAB (NAVY) PORT HUENEME CA
|
| The document provides protocol for evaluating friable asbestos material conditions and determining, by use of the asbestos hazard index, if a Navy Occupational and Health deficiency abatement project should be initiated. Also included are: guidance on proper interim control measures, as well as guidance for selecting appropriate long-term control measures; writing valid specification for long-term control measures; standardized safety procedures; and personnel protection during maintenance and control of friable asbestos-containing ... |
|
| Target Tracking and Target Detection in TV - and FLIR - Imagery. |
NOV 1980 |
|
| Authors:
M. Bohner; FORSCHUNGSINSTITUT FUER INFORMATIONSVERARBEITUNG KARLSRUHE (GERMANY F R)
|
| This paper describes procedures for the detection of moving or stationary objects in single images and in image sequences, taken from a moving or stationary sensor. Primarily the objects are located on the ground in their natural enviornment so that simple detection procedures (e.g. detection by maximum intensity) cannot be applied. For those situations a tracking system has been designed, simulated on a digital computer and tested with an equipment ... |
|
| Noise Abating Sleeve. |
28 OCT 1980 |
|
| Authors:
George P. Kalaf; Irvin C. Henschen; DEPARTMENT OF THE NAVY WASHINGTON DC
|
| In an acoustic homing torpedo having a transducer section mounted forward of the nose shell, an elastomeric, acoustically transparent sleeve is installed over the torpedo nose section and extends aft of the discontinuity at the transducer/nose section interface, thereby reducing the torpedo self-noise generated by cavitation occurring at the discontinuity. (Author) |
|
| A Modified Prony Method Approach to Echo-Reduction Measurements of Time-Limited Transient Signals. |
16 JUN 1980 |
63 pages |
| Authors:
David H. Trivett; NAVAL RESEARCH LAB WASHINGTON DC
|
| A modified Prony method is presented for measuring the steady-state echo reduction of acoustic panels. The method extrapolates the steady-state amplitudes from the transient portion of the signal allowing time-limited measurements. The method is applied to measurements of square panels 76 cm on an edge and 0.95 cm-thick steel and aluminum in the frequency range of 3 - 10 kHz. The signals were time-limited to 200 microseconds (0.6 - 2.0 ... |
|
| Means of Defense from Production Noise, |
13 JAN 1978 |
|
| Authors:
A. S. Palashevskaya; FOREIGN TECHNOLOGY DIV WRIGHT-PATTERSON AFB OHIO
|
| Contents: Physical Nature of Sound (Noise); Physiological Effect of Industrial Noise or the Human Organism; Production Conditions; Instruments Procedure for the Measurement of Production Noise; Normalization of Noise Level in Production; Collective and Individual Protection against Production Noise; Technical Requirements with Respect to Noise Abatement of New Machines and Mechanisms; and Technical Specifications for Planning of Noisy Productions Operations. |
|
| Shipbuilding Materials (Sudostroitelnyye Materialy), |
28 JUN 1977 |
|
| Authors:
V. I. Vasilyev; M. B. Roshchin; Ye. V. Tovstykh; NAVAL INTELLIGENCE SUPPORT CENTER WASHINGTON D C TRANSLATION DIV
|
|
| Wearable Sound Attenuating Enclosure. |
02 DEC 1975 |
|
| Authors:
Robert S. Gales; Robert S. Harrah; DEPARTMENT OF THE NAVY WASHINGTON D C
|
| A lightweight noise attenuating enclosure is shaped to cover the head, neck and upper thorax. A rigid outer shell and a sound attenuation layer block up to ten db of ambient noise and a number of pads mounted along the mouth of the enclosure prevents the bypass of noise. Thusly fabricated, the enclosure is ideally suited to allow work site audiometry testing for the hearing loss caused by noisy machinery. ... |
|
| Tri-Plane Elevated Evaluation System. |
09 MAY 1975 |
|
| Authors:
Donald G. Smith; Earle Smaltz; ARMY MISSILE RESEARCH DEVELOPMENT AND ENGINEERING LAB REDSTONE ARSENAL ALA ADVANCED SENSORS DIRECTORATE
|
| A new test facility has been constructed in Test Area No. 1 at the US Army Missile Command, Redstone Arsenal, Alabama. This test facility provides a three-axis platform atop a 150-foot tower for evaluating any device not exceeding 1000 pounds in weight. This facility consists of three major elements: the 150-foot tower which includes an anechoic upper portion, a remote controlled three-axis position manipulator, and control instrumentation and true position ... |
|
| An Evaluation of High Level Noise and Its Reduction in a 3000 BTU/HR Gasoline-Engine-Powered Field Refrigeration Unit. |
APR 1975 |
|
| Authors:
William C. Brown; ARMY MATERIEL COMMAND TEXARKANA TEX INTERN TRAINING CENTER
|
| The report describes the results of research intended to determine the sources of high level airborne noise transmitted from a 3000 BTU/hr mobile refrigeration unit using an air-cooled engine as the prime mover. An electric motor was adapted to power the unit and the major noise producing components of the system (compressor, motor, fan) were analyzed separately to determine their contribution to the overall noise. Noise measurements with a sound ... |
|
| SST Technology Follow-On Program-Phase II, Noise Suppressor/Nozzle Development. Volume II. Noise Technology. |
MAR 1975 |
|
| Authors:
J. Atvars; C. P. Wright; C. D. Simcox; BOEING COMMERCIAL AIRPLANE CO SEATTLE WA
|
| Jet noise suppression, a major problem in the development of quiet airplane systems, has experienced a substantial technology advance as described in this report. Fundamental technology development has led to a better understanding of nozzle aerodynamics, noise generation and noise transmission processes. This report describes the results of a systematic, model-scale, multitube nozzle test program which generated far-field jet noise data, jet noise source location data, flow-profile data and jet ... |
|
| Noise Control Methodology for Army Construction and Materials Handling Equipment. |
MAR 1975 |
|
| Authors:
George W. Kamperman; Mary A. Nicholson; KAMPERMAN ASSOCIATES INC DOWNERS GROVE ILL
|
| A pragmatic noise control methodology is presented with emphasis on techniques for reducing the noise from existing vehicles. The Caterpillar model 830MB Tractor/Scraper is used as an example to show how the vehicle operator's noise exposure can be reduced 20 dBA. An extensive bibliography on contemporary noise control literature is also included. |
|
| The Effect of Fabric Parameters on Sound-Transmission Loss, |
01 OCT 1973 |
|
| Authors:
Margaret E. Nute; K. Slater; GUELPH UNIV (ONTARIO) DEPT OF CONSUMER STUDIES
|
| The dependence of acoustic-transmission loss on the weight, thickness, and cover of woven fabrics is investigated over a broad range of frequencies. In actual fabrics, these variables are seldon independent of each other, so that their composite effect, in which cover has been shown to predominate, must be considered. In simulated models, in which these parameters are isolated, fabric weight and cover are shown theoretically to have a direct influence ... |
|
| 727 Noise Retrofit Feasibility. Volume III. Upper Goal Flight Testing and Program Summary. |
JUN 1973 |
|
| Authors:
D. L. Hiatt; M. B. McKaig; BOEING COMMERCIAL AIRPLANE CO SEATTLE WASH
|
| The work consisted of flight testing of the quiet-nacelle configuration developed in phase 2 in fulfillment of the FAA upper noise reduction goals for the 727 airplane, along with parallel flight testing of the 727 production nacelle as a baseline. All testing was performed on a model 727-100 airplane, with results extrapolated to the long-body 200 model. The phase 2 nacelles consist of peripheral acoustic lining in all inlets plus ... |
|
| Real-Ear Sound Attenuation Characteristics of the Sierra P/N 791 AVC Helmet, |
JUN 1973 |
|
| Authors:
Robert T. Camp Jr.; Alan L. Croshaw; Ben T. Mozo; Gordon A. Schott; Rohinton N. Guzdar; ARMY AEROMEDICAL RESEARCH LAB FORT RUCKER ALA
|
| The DH-132 was tested and approved as a standard helmet for the protection of the U. S. Army tank crewmen. In addition to this helmet, the Sierra P/N 791 AVC was submitted for test and evaluation for consideration as a second standard helmet. The real-ear attenuation test results show that the Sierra helmet significantly failed the attenuation specifications and therefore did not meet the attenuation requirements established by The Surgeon ... |
|
| An Acoustic-Noise Reduction Modification Kit for the AN/TPS-32 Radar System. |
25 APR 1973 |
35 pages |
| Authors:
E. Schiller; R. P. Kaufman; J. P. Wier; NAVAL ELECTRONICS LAB CENTER SAN DIEGO CA
|
| Report of a study of the total acoustic noise environment of the AN/TPS-32 radar installation at MCAS, Santa Ana, California, in terms of hearing hazard to personnel and degradation of speech communications. Noise sources were identified, and sound-spectrum levels at each source were measured and analyzed. Several methods for reduction/control of the noise were studied; the one chosen as most effective is described. (Author) |
|
| Environmental Impact of Noise from the Proposed Arnold Engineering Development Center (AEDC) High Reynolds Number Tunnel. |
MAR 1973 |
|
| Authors:
K. J. Plotkin; J. E. Robertson; J. A. Cockburn; WYLE LABS HUNTSVILLE ALA EASTERN OPERATIONS
|
| A study to evaluate the environmental impact of the noise produced by a proposed high Reynolds number tunnel (HIRT) under consideration at the Arnold Engineering Development Center (AEDC) has been conducted. The studies include theoretical analyses of the noise generation mechanisms associated with the operation of the facility, and scale-model experiments to provide base-line data for extrapolation to full-scale conditions. This assessment contains all pertinent data of relevance to the ... |
|
| A Latex IPN (Interpenetrating Polymer Network) Coating System for Damping Noise and Vibrations over a Broad Temperature Range |
JAN 1973 |
32 pages |
| Authors:
L. H. Sperling; Tai-Woo Chiu; R. G. Gramlich; D. A. Thomas; LEHIGH UNIV BETHLEHEM PA MATERIALS RESEARCH CENTER
|
| Based on the principles of constrained layer damping, 'Silent Paint' is a two-layer coating system capable of attenuating noise and vibration over a broad temperature range. The damping undercoat layer is composed primarily of a methacrylic/acrylic semi-compatible inter-penetrating polymer network (IPN) in latex form, with thickeners and preservative added. The constraining overcoat layer is based on a reinforced epoxy resin, and exhibits great stiffness. The total system, exhibiting significant damping ... |
|
| 727 Noise Retrofit Feasibility. Volume II. Upper Goal Design, Fabrication, and Ground Testing. |
NOV 1972 |
|
| Authors:
J. R. Anderson; H. G. Ridley; J. W. Smith; BOEING COMMERCIAL AIRPLANE CO SEATTLE WASH
|
| The work performed in phase 2 of the contract was development, design, fabrication, and ground testing of a flightworthy quiet-nacelle configuration conforming to the FAA upper noise-reduction goals for the 727 airplane. The quiet-nacelle configuration tested consists of a double-ring, acoustically treated, side engine inlet; acoustically treated engine fan duct; and a multilobe, variable-geometry ejector/suppressor in the engine exhaust system. This quiet-nacelle configuration was ground tested to obtain comparative acoustic ... |
|
| State-of-the-Art Review of Turbine Engine Inlet Noise. |
NOV 1972 |
|
| Authors:
Robert B. Benham; NAVAL AIR PROPULSION TEST CENTER TRENTON N J PROPULSION TECHNOLOGY AND PROJECT ENGINEERING DEPT
|
| The report points out that turbine-type engine design is evolving in a direction which will make fan and compressor turbomachinery noise continually more obstrusive. The TF34 engine is representative of 'state-of-the-art' high bypass ratio subsonic turbofan technology. It contains no inlet noise-suppression design and the inlet noise exceeds Federal Air Regulation Part 36 take-off sideline noise limits by about 6PNdb. There are descriptions and theoretical presentations explaining the principal mechanisms ... |
|
| Ambient Noise Attenuation. |
OCT 1972 |
|
| Authors:
Alfred L. DiMattia; Guy V. Love; CBS LABS STAMFORD CT
|
| Noise attenuation of circumaural ear enclosures is limited to low frequencies by pumping action of the earcup which generates internal noise. Theoretical study showed that this internal noise is proportional to the entrance, or inside, area of the cushion if all other variables are kept equal; thus, it is important to keep the inside area as small as possible consistent with easy insertion over the pinna. The theoretical analysis included ... |
|
| Study of Noise in Air Route Traffic Control Center, Flight Service Station, Air Traffic Control Tower, and Remote Facilities. |
OCT 1972 |
|
| Authors:
J. M. Clinch; H. G. Wakeley; IIT RESEARCH INST CHICAGO ILL
|
| The report describes various methods of reducing noise in several FAA Air Traffic Control and Navigational Facilities that exceed the facility noise criteria recommended in a previous report. Noise control procedures for each facility under consideration are described as well as the reasons for selecting specific noise reduction methods. (Author) |
|
| The Development of a Wind Tunnel Facility for the Study of V/STOL Noise, |
AUG 1972 |
|
| Authors:
Paul Bauer; Sheila Widnall; MASSACHUSETTS INST OF TECH CAMBRIDGE FLIGHT TRANSPORTATION LAB
|
| An open-jet wind tunnel operating within an anechoic chamber was developed for the purpose of the study of V/STOL noise mechanisms. An existing low-speed conventional hardwalled wind tunnel was modified to operate as an open-jet tunnel; an anechoic chamber was then constructed around the test section. The resulting aerodynamic and acoustic characteristics of the tunnel are discussed. (Author) |
|
| British Acoustical Society Spring Meeting, 1972. |
28 JUL 1972 |
|
| Authors:
Alfred E. Victor; OFFICE OF NAVAL RESEARCH LONDON (ENGLAND)
|
| The proceedings of the 1972 Spring Meeting of the British Acoustical Society are discussed. The technical portion of the meeting consisted of two three-day parallel sessions on the topics of 'Ultrasonics for Industry' and 'Aerodynamic Noise Sources in Industry'. The papers that were presented are listed. A brief description of the addresses presented by the Rayleigh Gold and Silver medalists is given. (Author) |
|
| Effectiveness of Damping Tiles for Reducing Vibration of Plates in Water. |
30 MAY 1972 |
45 pages |
| Authors:
Russell A. Christman; Wayne A. Strawderman; NAVAL UNDERWATER SYSTEMS CENTER NEWPORT R I
|
| The effectiveness of damping tiles in reducing the vibration response of a point-excited, clamped-edge plate immersed in water was investigated in a combined theoretical and experimental program. Comparisons of measured acceleration spectra for damped and undamped plates in both air and water environments indicate that damping tiles are less effective in a water environment than in air. A theoretical solution, based on thin-plate theory, of the acceleration power spectral density ... |
|
| 727Noise Retrofit Feasibility. Volume I. Lower Goal Design, Fabrication, Ground and Flight Testing. |
MAR 1972 |
|
| Authors:
R. B. Tate; H. G. Ripley; J. A. Lambert; BOEING CO SEATTLE WASH COMMERCIAL AIRPLANE GROUP
|
| The work performed in Phase 1 of the contract was design, fabrication, and ground testing of a treated nacelle configuration conforming to the FAA lower noise reduction goals for the 727 airplane. The nacelle configuration tested consists of acoustically treated side engine inlet, fan duct and tailpipe. This nacelle configuration was developed by the Boeing Comapny, flight tested and certificated in July 1971. The same nacelle was then used to ... |
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Reports by Keyword(s)
ACOUSTIC INSULATION
