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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

The impact and abatement of aircraft noise with reference to Australian capital cities /

Brewster, Roger James. January 1976 (has links) (PDF)
Thesis (M.T.P.) -- University of Adelaide, Dept. of Architecture, 1976.
2

Aircraft noise regulation

Ionescu, Irina Gabriela January 2004 (has links)
Aircraft noise is one of the most controversial environmental concerns in the aviation industry, partly due to the difficulty in harmonizing countries' regulation regarding this issue. The purpose of this thesis is to analyze the ways in which aircraft noise is regulated at the national and international levels, and to compare the legislative responses to aircraft noise issues in Europe and North America. Each of the four main chapters of the thesis takes into consideration a different aspect of the problem. The first chapter describes the objective and subjective ways of measuring aircraft noise. This process is necessary in order to allow the legislation to meet its purpose, namely, to protect the environment, the sources of the aircraft noise, and the effects of the aircraft noise on people. The second chapter describes the evolution of aircraft noise issues at the national levels in the US and throughout the EU, respectively, as well as at the international level, such as at the ICAO. The third chapter analyses the EU Regulation 925/1999, which created tension between the EU and the US due to its alleged discriminatory nature. This thesis examines the arguments of both sides. Finally, the fourth chapter analyses the noise certification standards developed by ICAO, namely the "balanced approach".
3

Acoustic emission source location in composite aircraft structures using modal analysis

Aljets, Dirk January 2011 (has links)
The aim of this research work was to develop an Acoustic Emission (AE) source location method suitable for Structural Health Monitoring (SHM) of composite aircraft structures. Therefore useful key signal features and sensor configurations were identified and the proposed method was validated using both artificially generated AE as well as actual AE resulting from damage. Acoustic Emission is a phenomenon where waves are generated in stressed materials. These waves travel through the material and can be detected with suitable sensors on the surface of the structure. These stress waves are attributed to propagating damage inside the material and can be monitored while the structure is in service. This makes AE very suitable for SHM, in particular for aircraft structures. In recent years composite materials such as carbon fibre reinforced epoxy (CFRP) are increasingly being used for primary and secondary structures in aircraft. The anisotropic layup of CFRP can lead to different failure mechanisms such as delamination, matrix cracking or fibre breakage which affects the remaining life time of the structure to different extents. Accurate damage location is important for SHM systems to avoid further inspections and allows for a maintenance scheme which considers the severity of the damage, due to damage type, extent and location. This thesis presents a novel source location method which uses a small triangular AE sensor array. The method determines the origin of an AE wave by a combination of time of arrival and modal analysis. The small footprint of the array allows for a fast and easy installation in hard-to-reach areas. The possibility to locate damage outside and at a relatively far distance from the array could potentially reduce the overall number of sensors needed to monitor a structure. Important wave characteristics and wave propagation in particular in CFRP were investigated using AE simulated by an artificial source and actual damage in composite specimens.
4

Computer Method for Airport Noise Exposure Forecast

Bateman, John M. 04 1900 (has links) (PDF)
Florida Technological University College of Engineering Thesis / The major problem facing air transportation for the next decade is aircraft noise. The noise level due to the operation of large ject aircraft has created a very serious annoyance problem to the poeople living near of adjacent to jet airports. The noise problem has developed both for take-off and landing operations of these aircraft with take -off noise causing the greatest annoyance factor. A technique called Noise Exposure Forcase (NEF) has been developed to identify the annoyance factor of these noises to people and activities on the ground. With these NEF ratings or numbers, planners can better determind the type of buildings and activities to locate in the vicinity of airports. This paper presents a computer method for determining NEF areas or contours which eliminate the necessity of performing laborous hand calculations and iterations normally required to determine a given NEF locus about an airport. A land use compatability table showing land use versus NEF numbers is given on page 3. A sample computer program is given on pages 21 through 25 of teh appendix and a sample computer output page is given on page 26. The computer technique developed for this paper can be used for any airport. / M.S.; / Masters; / Engineering; / Environmental Systems Management; / 26 p. / 26 leaves, bound ; 29 cm.
5

Managing aircraft noise

彭遠輝, Pang, Yuen-fai, Alson. January 2002 (has links)
published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management
6

Dynamic cutback optimization

Jayaraman, Shankar 15 April 2010 (has links)
The focus of this thesis is to develop and evaluate a cutback noise minimization process - also known as dynamic cutback optimization - that considers engine spool down during thrust cutback and is consistent with ICAO and FAR Part 36 noise certification procedures. Simplified methods for flyover EPNL prediction used by propulsion designers assume instantaneous thrust reduction and do not take into account the spooling down of the engine during the cutback procedure. The thesis investigates if there is an additional noise benefit that can be gained by modeling the engine spool down behavior. This in turn would improve the margin between predicted EPNL and Stage 4 noise regulations. Modeling dynamic cutback also impacts engine design during the preliminary and detailed design stages. Reduced noise levels due to cutback may be traded for lower engine fan diameter, which in turn reduces weight, fuel burn, and cost.
7

GIS in aircraft noise exposure assessment, Tsuen Wan district, Hong Kong

Lam, Yee-man., 林綺雯. January 2004 (has links)
published_or_final_version / abstract / toc / Geography / Master / Master of Geographic Information System
8

Noise problem after the opening of Hong Kong International Airport at Chek Lap Kok

Chan, Tin-chi, Kenneth., 陳天賜. January 2000 (has links)
published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management
9

Effects of jet aircraft overflights and other potential disturbances on behavioral responses and productivity of nesting peregrine falcons

Nordmeyer, Dana L. 08 April 1999 (has links)
In order to examine the potential impact of military jet overflights and other disturbances on productivity of peregrine falcons (Falco peregrinus), we observed behavioral reactions of peregrines to disturbances at nests along the Tanana River, Alaska during the 1995-1997 breeding seasons. Military jets conducted low-altitude flights over a sample of nests under observation in each year (experimental nests), while other nests were not intentionally overflown (reference nests). Other disturbances occurred at random. Animal noise monitors (ANMs), which collect and store data on noise disturbance levels, were deployed at each observed nest. A total of 878 above-threshold (��� 85 dB) overflights were recorded by the ANMs during the course of the study. A total of 401 close (defined as ��� 1000 m slant distance from the nest) overflights by subsonic F-16, F-15, A-10, Harrier, Jaguar, or Tornado jet aircraft were recorded during observations. Close overflights by military jets accounted for 63% of all observed potential disturbances at experimental nests; they accounted for 2.6% of all observed potential disturbances at reference nests. Other potential disturbances at reference nests included civilian fixed-wing aircraft (41%), boats (33%), avian predators (17%), helicopters (5%), and mammalian predators (1%). Peregrine falcons responded differently to animate and inanimate sources of disturbance, and responded most intensely and most frequently to other raptors, particularly conspecifics. Flight reactions were common, but not in response to inanimate sources. Among inanimate potential disturbances, falcons responded most intensely to boats (6% of reactions involved flight), and least intensely to helicopters (3%) and fixed-wing aircraft (2%). Intensity of reactions to military jets was indistinguishable from that to either boats or other aircraft. Intense behavioral responses (including flight reactions) to military jet overflights were rarely observed in this study, even at slant distances <500 m, and no intense behavioral responses were observed at slant distances >550 m. Peregrine falcon productivity (number of fledglings produced per nesting attempt) in the study area was within the normal range for Interior Alaska and the Tanana River. Dose of jet aircraft disturbance was not correlated with productivity. Productivity was, however, negatively correlated with reactivity of both individual falcons and mated pairs. Those falcons that responded more intensely to overflights tended to have lower productivity. The sensitivity of breeding peregrine falcons to low-altitude jet overflights is a better indicator of subsequent productivity than actual dose of overflights. This is likely a reflection of lower parental quality/investment among breeding pairs with high reactivity (i.e., younger, less experienced parents are less likely to be productive). / Graduation date: 1999
10

Aircraft noise stress and the effects on human health : a cross-sectional study in metropolitan Minnesota

Meister, Edward A. 29 April 1996 (has links)
Although the adverse auditory effects of noise have been the focus of occupational health research for decades, little is known about the nonauditory health effects that result from noise exposure. The focus of this research was the nonauditory health effects of exposure to commercial aircraft noise (CAN) overflights. It was theorized that CAN exposure resulted in an ongoing stress-response that had the potential to be harmful to human health over time. Two aspects of CAN were considered; the sound level intensity (dBA), and the frequency of overflights. Data were collected by a stratified random sampling design in the CAN exposed neighborhoods of Eagan, St. Paul, Minneapolis, and Bloomington, and in control communities of Shoreview and Mounds View, all located in Minnesota (n=4000). A written questionnaire was used to measure; (1) health (MOS-36 Scale), (2) behavioral and emotional coping strategies, (3) noise sensitivity, (4) annoyance levels, and (5) demographic data. Aircraft noise levels and overflight data were obtained in cooperation with the Metropolitan Airport Sound Abatement Commission. Results showed significantly higher stress levels and lower health measures by CAN exposure type. These findings occurred primarily in communities exposed to high frequencies of aircraft overflights. Multivariate analysis revealed significant reductions for the three main health measures of General Health (GH), Sense of Vitality (Vitality), and Mental Health (MH), based on CAN exposure type. Post-hoc contrast analysis indicated that GH, Vitality, and MH scores were worst with high frequency of overflights. Behavioral copers had significantly fewer stress symptoms and used fewer stress medications than non-behavioral copers. Non-normalized emotional copers had significant negative associations with Gil, Vitality, and MH; however, these correlations were weak. Noise sensitivity levels were not significantly different among the CAN exposed communities; however noise annoyance levels were significantly higher than controls, and were the highest with high frequency of overflights. Finally, multivariate analysis of covariance indicated significant reduction for health measures based on CAN exposure types after adjusting for all effect modifiers (covariates) in the study. Vitality was the most consistently impacted by CAN exposure, and this was particularly the case for subjects exposed to high frequency of aircraft overflights. / Graduation date: 1996

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