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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.
21

The effects of noise and time pressure on cognitive performance

St. Pierre, Matthew. January 2009 (has links)
Thesis (M.A.)--Northern Kentucky University, 2009. / Made available through ProQuest. Publication number: AAT 1465599. ProQuest document ID: 1814562591. Includes bibliographical references (p. 67-72)
22

Design of randomly placed microphone array

Jasti, Srichandana. January 2006 (has links) (PDF)
Thesis (M.S.)--University of Alabama at Birmingham, 2006. / Description based on contents viewed Jan. 29, 2007; title from title screen. Includes bibliographical references.
23

Hluková mapa v GIS / Noise map in GIS

Awadová, Thuraya January 2012 (has links)
The aim of this thesis is to create a noise map in a geographic information system. First of all, physical features of sound and the basics concerning the spatial, physiological and atmospheric acoustics domain will be introduced. Furthermore, we will analyse noise and its possible influence on the health of people. Substantial part of this thesis will be devoted to the methodology of noise measurement in urban agglomerations and to the issue of creating noise maps. The methodology of noise measurement in a particular area will be determined on the basis of the theoretical background. Geographic information system ArcView 9.2 from the ARCDATA firm (Ltd.) will be used for creating the noise map. The final noise map will be compared to the current hygienic limits. For comparison reasons an analysis of noise map using software CadnaA, which is used in professional analysis of noise studies, will be included in this thesis too.
24

Investigation of noise and disturbance from vehicles crossing cattle grids and examination of options for mitigation

Watts, Gregory R., Pheasant, Robert J., Khan, Amir 16 September 2016 (has links)
Yes / Cattle grids are used on roads and tracks to prevent grazing animals from leaving an open space without fencing onto a more controlled area where access to the road from surrounded land is more limited. They are widely used in the UK at the entrances to common and moorland areas where animals are free to roam, but also on private drive entrances. Typically, they consist of a series of metal bars across the road that are spaced so that an animal’s legs would fall through the gaps if it attempted to cross. Below the grid is a shallow pit that is intended to further deter livestock from using that particular crossing point. The sound produced as vehicles cross these devices is a characteristic low frequency “brrrr” where the dominant frequencies relates to the bar passage frequency under the tyres. The sound can be disturbing to riders and their horses and walkers and residents living close by as evidenced by press reports and the need to consider noise aspects in planning for new installations. For this reason and due to the lack of available information on the size and nature of the problem measurements and recordings have been made at a number of sites in Yorkshire in the UK. In addition, questionnaire surveys of residents living close by and façade measurements have also been used to gauge impact. Results show that there is a wide variation in the maximum noise level produced by cattle grids of apparently similar design. This can be related to impact noise produced by the movement of all or part of the grid as the frame comes under impulsive loading as the vehicle crosses. It was further established that some residents living close to the cattle grids were disturbed by the noise, and in some cases vibration, and wanted them removed or suitably modified. Means of reducing the problem are proposed.
25

Computer Aided Noise Prediction In Heating, Ventilating And Air Conditioning Systems

Gungor, Faruk Emre 01 January 2003 (has links) (PDF)
This thesis aims at preparing a user-friendly software tool for the prediction and analysis of the noise generated in Heating, Ventilating and Air Conditioning (HVAC) Systems elaborating the standardized prediction formulae and data coming from the research studies. For the analysis portion of the software, different types of indoor noise criteria are introduced and implemented in the software to ease the investigation of the level and the quality of the sound perceived by the occupant in a room through such criteria. General software structure and implementation of HVAC elements are explained by different userinterface samples in the thesis. Several case studies are presented to demonstrate the capabilities of the tool prepared in VISUAL BASIC programming language within the scope of the study.
26

Noise from wind turbines /

Fégeant, Olivier, January 1900 (has links)
Diss. (sammanfattning) Stockholm : Tekn. högsk., 2001. / Härtill 7 uppsatser.
27

Hluk na farmách pro odchov brojlerů a jeho šíření do okolního prostředí. / Noises on farms for breeding broilers and its spreading to surrounding neighbourhood

TŮMA, Marek January 2013 (has links)
The aim of this thesis on the topic "Noises on farms for breeding broilers and its spreading to surrounding neighbourhood" was to find out how the noise load influences the surroundings of two farms for breeding broilers. Repeated measures and following analysis of the particular values of the noise load, was used to determine, whether the relevant legislation and other norms are respected. Calculations of equivalent level of acustic pressure were used to compare chosen cases and to final evaluation.
28

Interdisciplinary study into the effect of a marine renewable energy testing facility on the underwater sound in Falmouth Bay

Garrett, Joanne Katherine January 2015 (has links)
Wave energy has the potential to contribute considerably to the UK's energy mix. The marine environment is already subjected to many anthropogenic pressures. There is a need to develop the industry as sustainably as possible. A key concern is the potential for underwater noise to affect marine life. A wave energy converter (WEC; BOLT Lifesaver, Fred Olsen Ltd.) was deployed at the Falmouth Bay marine renewable energy test site (FaBTest). The underwater sound levels were recorded at this site for a two week baseline period, a five-day installation period and intermittent operational and non-operational activity from March 2012 - November 2013. The recordings were also analysed for the Marine Strategy Framework Directive (MSFD) indicator third octave bands of 63-Hz and 125-Hz for shipping noise. The median and modal sound levels in Falmouth Bay were found to be loudest in the frequency range 100 Hz - 1 kHz and affected by local shipping activity. During installation activity, the sound levels were louder at all frequencies recorded as compared to similar periods with no installation activity, with a mean difference of 6.9 dB Hz-1 in the range 10 Hz to 48 kHz. Long term marine renewable energy construction projects may affect the MSFD indicator bands. There was little overall difference in the average sound levels for the operational and non-operational periods as the median PSD levels were louder by an average of 0.04 dB Hz-1 during the operational activity as compared to the non-operational activity. The results of this study indicate that the effect of a single WEC device on the overall sound levels in Falmouth Bay is relatively low considering the substantial presence of shipping in the area. However, in the immediate vicinity of the device (<200 m), the sound produced was found to be of significance to marine animals. It therefore requires considering in future deployments, particularly at a site with little anthropogenic activity.
29

Mapeamento ac?stico como ferramenta para predi??o de ru?do urbano na ?rea de influ?ncia do est?dio Arena das Dunas, Natal/ RN

Pinto, D?bora Nogueira 25 July 2013 (has links)
Made available in DSpace on 2014-12-17T13:57:12Z (GMT). No. of bitstreams: 1 DeboraNP_DISSERT.pdf: 3960791 bytes, checksum: 9647ee4242a9677af8d31483a39ab9ab (MD5) Previous issue date: 2013-07-25 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / The Noise Pollution causes degradation in the quality of the environment and presents itself as one of the most common environmental problems in the big cities. An Urban environment present scenario and their complex acoustic study need to consider the contribution of various noise sources. Accordingly to computational models through mapping and prediction of acoustic scene become important, because they enable the realization of calculations, analyzes and reports, allowing the interpretation of satisfactory results. The study neighborhood is the neighborhood of Lagoa Nova, a central area of the city of Natal, which will undergo major changes in urban space due to urban mobility projects planned for the area around the stadium and the consequent changes of urban form and traffic. Thus, this study aims to evaluate the noise impact caused by road and morphological changes around the stadium Arena das Dunas in the neighborhood of Lagoa Nova, through on-site measurements and mapping using the computational model SoundPLAN year 2012 and the scenario evolution acoustic for the year 2017. For this analysis was the construction of the first acoustic mapping based on current diagnostic acoustic neighborhood, physical mapping, classified vehicle count and measurement of sound pressure level, and to build the prediction of noise were observed for the area study the modifications provided for traffic, urban form and mobility work. In this study, it is concluded that the sound pressure levels of the year in 2012 and 2017 extrapolate current legislation. For the prediction of noise were numerous changes in the acoustic scene, in which the works of urban mobility provided will improve traffic flow, thus reduce the sound pressure level where interventions are expected / A Polui??o Sonora provoca degrada??o na qualidade do meio ambiente e se apresenta como um dos mais frequentes problemas ambientais nas grandes cidades. Os ambientes urbanos possuem cen?rios ac?sticos complexos e seus estudos precisam considerar a contribui??o de fontes sonoras diversas. Nesse sentido, os modelos computacionais, por meio do mapeamento e predi??o do cen?rio ac?stico, se tornam importantes, uma vez que possibilitam a realiza??o de c?lculos, de an?lises e de relat?rios que permitem a interpreta??o de resultados satisfat?rios. O bairro de estudo ? o bairro de Lagoa Nova, ?rea central da cidade do Natal, o qual passar? por grandes mudan?as no espa?o urbano devido ?s obras de mobilidade urbana previstas para o entorno do est?dio Arena das Dunas em decorr?ncia da Copa de 2014 e as consequentes mudan?as da forma urbana e no tr?fego. Dessa forma, este trabalho objetiva avaliar o impacto sonoro provocado pelas altera??es vi?rias e morfol?gicas no entorno deste est?dio no bairro de Lagoa Nova em Natal, a partir de medi??es in loco e do mapeamento com a utiliza??o do modelo computacional SoundPLAN no ano 2012 e a evolu??o do cen?rio ac?stico para 2017. Para tal an?lise, realizou-se, primeiramente, a constru??o do mapeamento ac?stico atual com base no diagn?stico ac?stico do bairro, mapeamento f?sico, contagem classificada dos ve?culos e medi??o do n?vel de press?o sonora; e para se construir a predi??o de ru?do, observou-se, para a ?rea de estudo, as modifica??es previstas para o tr?fego, forma urbana e obras de mobilidade. Conclui-se que os n?veis de press?o sonora do ano 2012 e para 2017 extrapolam, em parte, a legisla??o vigente. Para a predi??o do ru?do foram verificadas v?rias modifica??es no cen?rio ac?stico, no qual as obras de mobilidade urbana previstas melhorar?o o fluxo do tr?fego, consequentemente, reduzir?o o n?vel de press?o sonora onde est?o previstas as interven??es
30

Untersuchung des Einflusses der variierenden urbanen Grenzschicht auf die Schallausbreitung

Fischer, Gabi, Ziemann, Astrid 26 September 2017 (has links)
Der Risikofaktor Lärm stellt vor allem in urbanen Gebieten ein großes Umweltproblem mit teilweise erheblichen gesundheitlichen Langzeitauswirkungen für die Stadtbevölkerung dar. Dabei hängt die Ausbreitung des Schalls von einer Störquelle, wie z.B. dem Straßenverkehr, besonders auf größeren Strecken von der Atmosphärenstruktur ab. Das Ziel dieser Arbeit bestand darin, den Einfluss der tageszeitlich variierenden urbanen Grenzschicht auf die Schallausbreitung unter Verwendung eines Schallstrahlenmodells abzuschätzen. Basis dieser Berechnungen bildeten analytisch erzeugte urbane Vertikalprofile der Temperatur, Windgeschwindigkeit und Windrichtung. Die Auswertungen der Karten der meteorologisch bedingten Zusatzdämpfung zeigten eine sichtbare zusätzliche Beeinflussung der Schallausbreitung durch die spezielle Struktur der urbanen Grenzschicht. Besonders im Nahbereich der Quelle traten nachts in Windrichtung bei labiler Atmosphärenschichtung Zonen erhöhter Lärmbelastung auf. / Especially in urban regions the risk factor noise is a huge problem, which may have a notable impact on (human) health on long-time scales. The sound propagation of a disturbing source, e.g. traffic noise, depends for larger distances in particular on the structure of the atmosphere. The aim of this study was to estimate the influence of the urban boundary layer on the propagation of sound using a sound ray model. Therefore, urban vertical profiles of temperature, wind speed, and wind direction for day and night time conditions were calculated analytically. The resulting maps considering excess attenuation of sound due to meteorology yielded an additional influence on the sound propagation in consequence of the defined structure of the urban boundary layer. Particularly in downwind areas close to the source the impact of noise increases regionally at night for the cases of unstable atmospheric layering.

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