Topics: Radio Program, Traffic law, Rock and Roll Hall of Fame inductees, Companies listed on the New York...
Topics: Radio Program, American politicians, Police ranks, Law enforcement, Taxation, National supreme...
Topics: Radio Program, American Protestants, Republics, Labour law, New England Patriots players, Precious...
Topics: Radio Program, Deaf culture, Deafness, American jazz pianists, Swing musicians, Hearing, Sign...
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Jan 20, 2021
01/21
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This is a vibration dampener for Prusa i3. It is very effective as it reduces a lot of decibels of the noise of the printer. Once I mesured the noise with and without this dampener but I don't remember the exact results. I think it was aproximatively 70 Db at 1m without the dampener on a wooden table, and 50 Db in the same conditions with the Springy Feet. So approximately -20 Db wich is hudge ! It fits perfectly under the feets of my Prusa i3 Rework, it should fit under an Original Prusa i3...
Topics: spiral, Noise_Reduction, dampener, coil, Vibration_Dampers, vibration, vibration_dampener, 3D...
Topics: Radio Program, NPR programs, International relations, Diplomacy, Bullying, Hearing, Noise, Fuel...
Gold-colored foam wedges shield test subjects from outside noises during an acoustics test at NASA's Langley Research Center in Hampton, Va. NASA researchers study people's perception of aircraft sounds, especially the role of rattle noises and vibration. They use this information to help design quieter aircraft. Credit: NASA Langley/Sean Smith
Topics: NASA, Langley, image, image of the week, quiet, airplanes, aircraft, noise, reduction, engine...
Source: http://www.nasa.gov/centers/langley/multimedia/iotw-boomroom.html
Topics: Radio Program, Debt, Credit, Kennedy Center honorees, American singers, Economics terminology,...
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Topics: Radio Program, Deaf culture, American jazz pianists, Deafness, Swing musicians, Sign languages,...
Topics: electronics, pin, mhz, kit, free, model, electronic, digital, frequency, power supply, stringy...
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Jul 19, 2010
07/10
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Augustine Sasso
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New Myfc podcast show no.1 v2 mp4 version. Noise reduction
Topic: New MYC Podcast Show No.1 V2 MP4 Noise reduction
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Mar 3, 2021
03/21
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Artur Gringoling (Gringoling)
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Noise reduction Feet for your Makerbot
Topics: printer_feet, soft, Noise_Reduction, tpe, anti_vibration, replicator_2, feet, vibration,...
This report describes the development and ground testing of an acoustic sensor to detect boundary layer transition on models in high acoustic noise wind tunnel facilities. The noise cancellation transducer utilizes the Boundary Layer Acoustic Monitor (BLAM) detection concept to monitor the flow and employs a subtractive technique to cancel out coherent noise components to improve the signal to noise ratio.
Topics: DTIC Archive, Peckham,Vernon D, KAMAN SCIENCES CORP COLORADO SPRINGS COLO, *ACOUSTIC DETECTION,...
A coannular jet was equated with a single stream equivalent jet with the same mass flow, energy, and thrust. The acoustic characteristics of the coannular jet were then related to the acoustic characteristics of the single jet. Forward flight effects were included by incorporating a forward exponent, a Doppler amplification factor, and a Strouhal frequency shift. Model test data, including 48 static cases and 22 wind tunnel cases, were used to evaluate the prediction method. For the static...
Topics: NASA Technical Reports Server (NTRS), ACOUSTIC ATTENUATION, JET AIRCRAFT NOISE, NOISE REDUCTION,...
A telemetry data processing system was defined of the Data Reduction. Data reduction activities in support of the developmental flights of the Space Shuttle were used as references against which requirements are assessed in general terms. A conceptual system design believed to offer significant throughput for the anticipated types of data reduction activities is presented. The design identifies the use of a large, intermediate data store as a key element in a complex of high speed, single...
Topics: NASA Technical Reports Server (NTRS), DATA PROCESSING, DATA REDUCTION, SPACE TRANSPORTATION SYSTEM,...
The primary of this test program was to measure the acoustic environment in the hush house facility located at Kelly Air Force Base, Texas, during operation of the F-16 aircraft to ensure that aircraft structural acoustic design limits were not exceeded. The acoustic measurements showed that no sonic fatigue problems are anticipated with the F-16 aircraft aft fuselage structure during operation in the hush house. The measured acoustic levels were less than those measured in an F-16 aircraft...
Topics: DTIC Archive, Miller, Vincent R, AIR FORCE WRIGHT AERONAUTICAL LABS WRIGHT-PATTERSON AFB OH, *JET...
The broadband component of fan noise has grown in relevance with an increase in bypass ratio and incorporation of advanced fan designs. Therefore, while the attenuation of fan tones remains a major factor in engine nacelle acoustic liner design, the simultaneous reduction of broadband fan noise levels has received increased interest. As such, a previous investigation focused on improvements to an established broadband acoustic liner optimization process using the Advanced Noise Control Fan...
Topics: NASA Technical Reports Server (NTRS), TURBOFAN ENGINES, FAN BLADES, ACOUSTIC PROPAGATION,...
Efforts to develop an engine noise reduction technology suitable for use on subsonic and conventional takeoff and landing type aircraft are reported. Two baseline quiet engines were developed and tested. The engines were designed with the following quiet features: (1) high bypass ratio engine, (2) large rotor-stator spacing of rotor chords, (3) reduced rotor tip speeds, (4) sound absorbing liners in inlet-outlet ducts, and (5) an optimum ratio from stator to rotor blades. Test results show that...
Topics: NASA Technical Reports Server (NTRS), COMMERCIAL AIRCRAFT, ENGINE NOISE, NOISE REDUCTION, QUIET...
An improved method for the design of expansion-chamber mufflers is described and applied to the task of reducing exhaust noise generated by a helicopter. The method is an improvement of standard transmission-line theory in that it accounts for the effect of the mean exhaust-gas flow on the acoustic-transmission properties of a muffler system, including the termination boundary condition. The method has been computerized, and the computer program includes an optimization procedure that adjusts...
Topics: NASA Technical Reports Server (NTRS), ENGINE NOISE, EXHAUST SYSTEMS, HELICOPTER ENGINES, MUFFLERS,...
The feasibility was studied of modifying a JetStar airplane into a demonstrator of benefits to be achieved from incorporating active control concepts in the preliminary design of transport type aircraft. Substantial benefits are shown in terms of fuel economy and community noise by virtue of reduction in induced drag through use of a high aspect ratio wing which is made possible by a gust alleviation system. An intermediate configuration was defined which helps to isolate the benefits produced...
Topics: NASA Technical Reports Server (NTRS), AIRCRAFT DESIGN, CONTROL EQUIPMENT, CONTROL THEORY, DRAG...
Noise tests were conducted on a small-scale model of an externally blown flap lift augmentation system. The nozzle/wing model was subjected to external flow that simulated takeoff and landing flight velocities by placing it in a 33-centimeter-diameter free jet. The results showed that external flow attenuated the noise associated with the various configurations tested. The amount of attenuation depended on flap setting. More attenuation occurred with a trailing-flap setting of 20 deg than with...
Topics: NASA Technical Reports Server (NTRS), EXTERNALLY BLOWN FLAPS, FLIGHT SIMULATION, NOISE MEASUREMENT,...
Volume 3 of a three volume report is presented. Volume 3 contains the detailed aerodynamic test results plus the concept screening and model design report.
Topics: NASA Technical Reports Server (NTRS), ACOUSTIC MEASUREMENT, AERODYNAMIC CHARACTERISTICS, ANNULAR...
Turbomachines onboard aircraft operate in a highly complex and harsh environment. The unsteady flowfield inherent to turbomachines leads to several problems associated with safety, stability, performance and noise. In-flight surge or flutter incidents could be catastrophic and impact the safety and reliability of the aircraft. High-Cycle-Fatigue (HCF), on the other hand, can significantly impact safety, readiness and maintenance costs. To avoid or minimize these problems generally a more...
Topics: NASA Technical Reports Server (NTRS), ACTIVE CONTROL, AEROELASTICITY, AERODYNAMIC CHARACTERISTICS,...
An inflight evaluation of four aural protectors is presented. The hearing protection devices studied were ear muffs, plastic ear plugs, rubber ear plugs, and wax ear plugs. It is concluded that ear plugs are satisfactory for providing adequate sound attenuation in general aviation aircraft. However, two problems were found in the use of ear plugs; comfort and interference with cabin communications.
Topics: NASA Technical Reports Server (NTRS), AUDITORY DEFECTS, EAR PROTECTORS, GENERAL AVIATION AIRCRAFT,...
Two 1.829-m-(6-ft-) diameter fans suitable for a quiet engine for future short-takeoff-and-landing (STOL) aircraft were compared. Both fans were designed for a 1.2 pressure ratio with similar weight flows, thrusts, and tip speeds. The first fan, designated QF-9, had 15 rotor blades and 11 stator blades. The rotor was highly loaded and the tip solidity was less than 1. The QF-9 rotor blades had an adjustable pitch feature which can be used for thrust reversal. The second fan, designated QF-6,...
Topics: NASA Technical Reports Server (NTRS), ACOUSTIC MEASUREMENT, ENGINE NOISE, ROTOR BLADES...
The absorption characteristics of several fibrous materials of the Owens Corning 700 Fiberglas Series were measured to determine the variation in impedance as a function of incident angle of the sound wave. The results, indicate that the fibrous absorbents behave as extended reacting materials. The poor agreement between measurement and theory for sound absorption based on the parameters of flow resistance and porosity indicates that this theory does not adequately predict the acoustic behavior...
Topics: NASA Technical Reports Server (NTRS), ACOUSTIC ATTENUATION, ACOUSTIC EXCITATION, COMPOSITE...
A large and diverse number of computational techniques are routinely used to process and analyze remotely sensed data. These techniques include: univariate statistics; multivariate statistics; principal component analysis; pattern recognition and classification; other multivariate techniques; geometric correction; registration and resampling; radiometric correction; enhancement; restoration; Fourier analysis; and filtering. Each of these techniques will be considered, in order.
Topics: NASA Technical Reports Server (NTRS), AUGMENTATION, CLASSIFICATIONS, FILTRATION, FOURIER ANALYSIS,...
The aim of the SUNLITE program is to demonstrate the performance of ultra-stable laser systems in the environment of space. The program uses Non-Planar Ring Oscillators (NPRO) which have shown great promise for time and frequency standards with unprecedented resolution and stability. An immediate goal is to test NPRO oscillators in orbital free fall by 1994. During the past year there was remarkable progress in the design and pre-flight testing of the SUNLITE test package. Current theoretical...
Topics: NASA Technical Reports Server (NTRS), FREQUENCY STABILITY, FREQUENCY STANDARDS, LASERS, NOISE...
An apparatus and method for suppressing acoustic noise utilizes consecutive plates, closely spaced to each other so as to exploit dissipation associated with sound propagation in narrow channels to optimize the acoustic resistance at a liner surface. The closely spaced plates can be utilized as high temperature structural materials for jet engines by constructing the plates from composite materials. Geometries of the plates, such as plate depth, shape, thickness, inter-plate spacing,...
Topics: NASA Technical Reports Server (NTRS), ACOUSTIC ATTENUATION, DISSIPATION, LININGS, NOISE REDUCTION,...
The noise shielding potential of an inboard-wing catamaran aircraft when coupled with distributed propulsion is examined. Here, only low-frequency jet noise from mid-wing-mounted engines is considered. Because low frequencies are the most difficult to shield, these calculations put a lower bound on the potential shielding benefit. In this proof-of-concept study, simple physical models are used to describe the 3-D scattering of jet noise by conceptualized catamaran aircraft. The Fast Scattering...
Topics: NASA Technical Reports Server (NTRS), JET AIRCRAFT NOISE, AIRCRAFT DESIGN, NOISE REDUCTION, NOISE...
The leading Aeronautics program within NASA is the High Speed Research Program (HSR). The HSR program's highest priorities are high pay-off technologies for airframe and propulsion systems required for a high speed civil transport (HSCT). These priorities have been developed collaboratively with NASA, FAA and the US Industry (Boeing-McDonnell Douglas, Pratt & Whitney and General Electric). Phase one of the HSR program started on 1990, and concentrated on the environmental challenges of...
Topics: NASA Technical Reports Server (NTRS), NASA PROGRAMS, CIVIL AVIATION, GENERAL OVERVIEWS, SUPERSONIC...
Photographed on 05/18/2005. -- Curved duct test rig in no flow configuration as installed in the Anechoic Noise Research Facility (ANRF), building 1218A. People in photographs include: Beverly Anderson, Christal Kellam and Stan Hogge.
Topics: NOISE REDUCTION -- JET PROPULSION -- TES, What -- TES
Photographed on: 01/31/2000. -- Separate flow nozzle in building 1221B, room 116, Jet Noise Lab - Low Speed Aeroacoustics Wind Tunnel.
Topics: NOISE REDUCTION -- JET PROPULSION -- TES, What -- TES
Photographed on: 03/06/2000. -- Facility drag tare plate installed onto the jet engine simulator. Test was conducted in the Low Speed Aeroacoustic Wind Tunnel, Jet Noise Lab, building 1221-A.
Topics: NOISE REDUCTION -- JET PROPULSION -- TES, What -- TES
Photographed on: 07/09/2002. -- BPR = 5. Nozzle with pylon. Photographed in building 1221.
Topics: NOISE REDUCTION -- JET PROPULSION -- TES, What -- TES
Photographed on: 07/03/2002. -- Photographed in building 1221-A, Jet Noise Lab/Low Speed Aeroacoustic Wind Tunnel.
Topics: NOISE REDUCTION -- JET PROPULSION -- TES, What -- TES
Photographed on 05/18/2005. -- Curved duct test rig in no flow configuration as installed in the Anechoic Noise Research Facility (ANRF), building 1218A. People in photographs include: Beverly Anderson, Christal Kellam and Stan Hogge.
Topics: NOISE REDUCTION -- JET PROPULSION -- TES, What -- TES
Photographed on 05/18/2005. -- Curved duct test rig in no flow configuration as installed in the Anechoic Noise Research Facility (ANRF), building 1218A. People in photographs include: Beverly Anderson, Christal Kellam and Stan Hogge.
Topics: NOISE REDUCTION -- JET PROPULSION -- TES, What -- TES
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Topics: Radio Program, Christmas traditions, English folklore, Christmas, Holiday-related topics, East...
Topics: Radio Program, NPR programs, Electrical engineering, Engine technology, Front-wheel-drive vehicles,...
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Topics: Radio Program, NPR programs, NPR personalities, Legal professions, Public relations, Financial...
Photographed on: 03/25/99.
Topics: NOISE REDUCTION -- JET PROPULSION -- TES, What -- TES
Photographed on: 03/25/99.
Topics: NOISE REDUCTION -- JET PROPULSION -- TES, What -- TES
This report presents the results of a study of the acoustic and fluid dynamic characteristics of a shrouded slot nozzle. Experiments were carried out on a slot nozzle of aspect ratio 27 with an ejector shroud having a cross sectional area of four times the primary nozzle area. Parameters varied during the tests were, shroud length, shroud divergence ratio, and acoustical impedance of the shroud wall. Tests were conducted for primary flow Mach numbers from 0.5 to choking and stagnation...
Topics: DTIC Archive, Goethert,B H, TENNESSEE UNIV SPACE INST TULLAHOMA, *TURBOFAN ENGINES, *NOISE...
Topics: Radio Program, Gerontology, Commerce, Noise reduction, Hearing, Protective gear, Public relations,...
Topics: Radio Program, Major League Baseball first basemen, Audio engineering, Accountancy, Business law,...
The real noise reduction benefits which may be obtained through the use of one gear tooth form as compared to another is an important design parameter for any geared system, especially for helicopters in which both weight and reliability are very important factors. The design and testing of nine sets of gears which are as identical as possible except for their basic tooth geometry are described. Noise measurements were made at various combinations of load and speed for each gear set so that...
Topics: NASA Technical Reports Server (NTRS), DESIGN ANALYSIS, GEAR TEETH, GEARS, NOISE MEASUREMENT, NOISE...
Topics: Radio Program, Debt, Constitutional law, Banking, Credit cards, Writers from New York City,...
Topics: Radio Program, American jazz pianists, Deaf culture, NPR programs, Swing musicians, Deafness,...
Low-noise fan exit guide vanes are disclosed. According to the present invention a fan exit guide vane has an outer shell substantially shaped as an airfoil and defining an interior cavity. A porous portion of the outer shell allows communication between the fluctuations in the air passing over the guide vane and the interior cavity. At least one acoustically resonant chamber is located within the interior cavity. The resonant chamber is in communication with the porous portion of the outer...
Topics: NASA Technical Reports Server (NTRS), GUIDE VANES, LOW NOISE, NOISE REDUCTION, PATENTS, AIRFOILS,...
