Sök:

Sökresultat:

852 Uppsatser om Noise reduction - Sida 1 av 57

Aktiv bullerdämpning i ventilationssystem

Active headsets have been on the market for years and now it is time for something else to enter the stage. The technology of active Noise reduction can for exmple also be used in ventilation systems for reducing ventilation noise. An active control system principally consists of four important components, namely the downstream error microphone, the upstream detection or reference microphone, the digital signal processor (DSP) and a loudspeaker. The upstream reference microphone listen to the primary ventilation noise and sends it to the DSP which makes a phase shift to the signal and sends it to the loudspeaker. The loudspeaker sends out the opposite waveform of the incoming one and reduce the primary ventilation noise.

Aktiv bullerdämpning i ventilationssystem

Active headsets have been on the market for years and now it is time for something else to enter the stage. The technology of active Noise reduction can for exmple also be used in ventilation systems for reducing ventilation noise. An active control system principally consists of four important components, namely the downstream error microphone, the upstream detection or reference microphone, the digital signal processor (DSP) and a loudspeaker. The upstream reference microphone listen to the primary ventilation noise and sends it to the DSP which makes a phase shift to the signal and sends it to the loudspeaker. The loudspeaker sends out the opposite waveform of the incoming one and reduce the primary ventilation noise.

Bullertunneln : En utredning kring en ny bullerlösning vid trafikleder

The purpose of this Master Thesis has been to investigate the possibilities for a new type of Noise reduction solution that could decrease the negative effects resulting from larger traffic roads. The idea has been to construct a noise barrier with a roof ? like a tunnel placed on a road. The choice of material has been focused on transparent materials in order to lower visual intrusion and barrier effects. This project idea is called the Noise tunnel.After having investigated the current offer of noise solutions, it has been concluded that these solutions rarely provide a sufficient level of Noise reduction ? at least not when government regulations of acceptable noise levels are applied.

Bullerreduktion av hytt på Volvodumprar : Undersökning, mätning och analys

Too high levels of noise lead to various health problems and cost society billions of SEK peryear. In this thesis we have examined a model of the A40E articulated hauler at VolvoConstruction Equipment in Braås. We have tried to reduce cabin noise in an articulated hauler,while also providing a way on how to proceed with a machine when the cabin does not measureup to the sound requirement. The best way to find leaks were with a reference source of model4205 and its speaker HP 1001 from Brüel & Kjaer in the cab and then walk around and listen towhere the reference source was more prominent. In this way, we found that the edges and theplugs were sensitive areas.

Dämpning av ljud i Shift-by-Wire växelväljare : Noise damping in a Shift-by-Wire gear shifter

Constantly growing demands from the costumers in the Automotive industry forces the subcontractors to seek alternative ways to compete. One parameter of quality is the components tolerance against NVH(Noise, Vibraion & Harshness) aspects. Kongsbergs Automotive has developed a new gear shifter platform (Shift-by-Wire) that is sold to Alfa Romeo and used in of their car models. However, the company is not pleased with the components sound quality, therefore the main purpose of this thesis is to develope a number of concepts that is supposed to enhance these NVH-aspects.To get an understanding of the problem an analysis of the causes of the emitted sound has been done parallell to a product decomposition, function decomposition and a Ishikawa-diagram. Together with these methods has a litterature study been performed to get familiar with the physics of an impact and especially the emittment of noise.

Vegetation och ljudmiljö

Landscape architecture is a visual profession, but other senses also affect our interpretation of a place. Sounds can give us a lot of information about an environment, and they are often perceived as positive. Despite this, research about outdoor sounds most often focus on the reduction of unwanted sounds ? noise ? but the absence of noise does not result in a good soundscape. To accomplish this, sounds we appreciate are needed.

NOISE OCH MINNE

Detta arbete handlar om noise och hur det påverkar människans arbetsminne. Den litterära bakgrunden presenterar vad noise är, hur noise fungerar som musik samt en generell överblick över minne och arbetsminnet. Problemet som undersöktes var om noise kunde påverka förmågan att tillgodogöra sig visuell information mer än vad vitt brus gjorde. För att få ett svar på frågan skapades två versioner av ett enkelt spelmoment där testpersonerna, indelade i två grupper, fick se en siffersekvens som sedan skulle skrivas ner. Samtidigt spelades i spelmomentet antingen noise eller vitt brus upp.

Åtgärder för att minimera trafikbullers påverkan på ett rekreationsområde

The aim of this inquiry was to investigate the most appropriate measures to reduce noise impacts from road traffic on the Nydala recreational area in Umeå municipality due to the planned re-routing of the E4 motorway to an existing road along this area. The sound environment is an important part in the experience when we are visiting recreational areas. Noise is not only disturbing; the liberty from unwanted sounds also allows us to perceive natural sounds that are a benefit for the cultural experience. Therefore it is important to take actions to protect this well used area from traffic noise. The reasonable options to avoid noise impact in this case are to lower the speed limit, using a noise reducing coating or use noise protection screens and walls.

Värdet av tystnad : en värderingsstudie över Upplands Väsbybornas betalningsvilja för reducerat flygbuller

Since the spring 2003 the tenant-owner home association the Terrace in Upplands Väsby municipality lies straight under the approach route to Arlanda Airport?s new third landing chute. Noise levels of over 70 dB have been measured in the area, which exceeds National Board of Housing?s, values for traffic noise at a terrace in connection to housing. By using the method of hedonisk pricing the essay tries to find out if there exists a willingness to pay to reduce the noise in the area.

Buller : Hur planeras en bullerfri stad?

Milosevic, S. 2014. Buller ? Hur planers en bullerfri stad?. Kulturgeografiska institutionen, Uppsatser, Uppsala universitet. This essay is about noise pollution caused by urbanization.

Bakgrundsbrusets effekt på kognitiv prestation samt skapandet av falska minnen : Om bullrets inverkan i öppna kontorsmiljöer

This study aimed to explore how 31 collage students' cognitive performance and their ability to create false memories were affected by the exposure of an extraneous background noise. The studies main hypotheses were based on previous research on how extraneous noise affect the cognitive ability and the creation of false memories: 1) that an extraneous background noise increases the ability to create false memories, 2) that an extraneous background noise impairs the learning of cognitive information, 3) that an extraneous background noise contributes to an increased representation of fictional words, 4) that an extraneous background noise impedes the ability to understand speech . The results showed a tendency in which false memories increased in the condition without background noise, a result which goes in the opposite direction of the hypothesis. Furthermore, the result supported the hypothesis that the extraneous background noise impairs the learning of cognitive information. The results also showed that there was no effect between the conditions regarding the representation of fictional information.

Oljudens musik : En revolution i kompositionsteknik?

Noise music is created around sounds not often welcome in a musical context. Since the birth of electronic music in the 1950s a new perspective on composing has emerged. In electronic music, sounds and their timbre are as much important as melody, harmony and rhythm. This composing perspective is not often observed. Therefore I have examined a musical genre that stretches the boundaries of what we consider music, sound, noise, beautiful and terrible.

Undersökning av ljudnivåer på skolgårdar : - samt hur fasad och fönster dimensioneras med uppmätta värden

This report is written on commission by WSP Acoustics. The report studies the outdoor sound levels on school yards in Stockholm. The questions given by the company to be answered was what are the actual sound levels at diffrent school yards with low traffic noise and how can you construct a facade element that reduces the sound level from the outside and meet the indoor requirements. Mesurements for four hours was done at eight schools set north and south of the city centre. The measurement period included one school break and one lunch break.

Skalning och brusberäkning av tvåportsadaptorer

The goal of this work is to summarize the calculations for scaling and noise of twoportadaptor. Two different methods has been described and used for the final results..

Bil- och järnvägstrafikens inverkan på inomhusmiljön med avseende på ljud och luft : - I planerade bostäder på Haga

NCC has given us a commission to investigate a planned housing area in Haga, Karlstad, situated close to the traffic route Hagaleden and the railway. The housing area consists of one hundred apartments in five different houses. The houses are linked to each other by balconies with glass panels. A long carport is situated between Hagaleden and the housing area to absorb part of the noise from the road. The design of the housing area is creating a silent backyard.

1 Nästa sida ->