• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 15
  • 11
  • 7
  • 6
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 47
  • 47
  • 12
  • 12
  • 12
  • 10
  • 9
  • 8
  • 8
  • 8
  • 8
  • 7
  • 7
  • 6
  • 6
  • 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.
31

Resíduos de poli (tereftalato de etileno) e de pneu na confecção de pisos flutuantes para o isolamento do ruído de impacto / Poly (ethylene-terephthalate) and tyre residues in floating floors for impact sound insulation

CARVALHO, Maria Luiza de Ulhoa 21 August 2009 (has links)
Made available in DSpace on 2014-07-29T15:01:51Z (GMT). No. of bitstreams: 1 dissertacao maria luiza.pdf: 3132447 bytes, checksum: e48de2cde6494677cafaf830a4ead4f5 (MD5) Previous issue date: 2009-08-21 / The demographic growth has created a gain in urban solid waste that deteriorates the citizen s quality of life. High buildings represent the main way for accommodations in big cities for these growing urban populations. However, impact sound insulation has shown itself quite poor. In order to propose an alternative way of minimization to the two problems, residue generation and impact noise, this study aimed to investigate the viability of using poly (ethylene-terephthalate) - PET and rubber tire residues for impact sound insulation in floating floors. Plates of 1 m² with thickness of 1.5 and 2.5 cm to 1:4 and 1:5 (ciment:residue) ratios were molded for the acoustic experiments, as well as portable mortar slabs covered with high and popular quality floor coverings. The main methods used were ISO 140-7 (1998) for measuring the standardized impact sound pressure level, L nT, in one-third-octave bands and ISO 717-2 (1996) to calculate the weighted standardized impact sound pressure level, L nT,w. Both residues presented high sound insulation in relation to their references. It was observed that the results for the PET specimen were superior to those of the rubber tires residue. However, the results among the residues presented different tendencies as their ratio changed. While the impact sound insulation of the rubber tires samples decreased with the increase of residue, PET samples presented more insulation with residue increase. Another observed factor was that the high quality floor covering presented a significant superior impact sound isolation compared to the popular floor covering. Considering all results, it is possible to conclude that the use of the studied residues in floating floors contributes to impact sound insulation / O crescimento demográfico mundial tem criado um aumento na geração de resíduos sólidos urbanos e deteriorado a qualidade de vida dos cidadãos. As edificações altas se apresentam como a principal forma de acomodação da crescente população nas cidades, no entanto, o conforto sonoro em relação ao ruído de impacto tem se mostrado precário. Com o intuito de propor uma alternativa de minimizar ambos os problemas, a geração de resíduos e o ruído de impacto, a presente pesquisa teve como principal objetivo estudar a viabilidade de uso dos resíduos de poli (tereftalato de etileno) - PET e do pneu inservível na confecção de pisos flutuantes no isolamento do ruído de impacto. Placas de 1 m² com traço 1:4 e 1:5 (cimento:resíduo) nas espessuras de 1,5 e 2,5 cm foram moldadas para realizar os ensaios acústicos, assim como placas de argamassa armada revestida com cerâmica popular e de alto padrão. As principais metodologias utilizadas foram a ISO 140-7 (1998) para obter o nível de pressão sonora de impacto padronizada por bandas de terças de oitavas, L nT, e a ISO 717-2 para ponderar o valor único do nível de pressão sonora de impacto padronizado e ponderado, L nT,w. Ambos resíduos apresentaram isolamento superior em relação às respectivas referências. Observou-se que o isolamento do ruído de impacto das amostras com PET foi superior às com pneu. No entanto, os resultados entre os resíduos apresentaram tendências diferentes com a mudança do traço. Enquanto que o isolamento das amostras do pneu decaiu com o acréscimo do resíduo, as amostras com PET tiveram um ganho maior com o aumento do resíduo. Outro fator observado foi que o contrapiso com cerâmica de alto padrão apresentou um efeito significativo do isolamento em relação à cerâmica popular. Em vista de todos os resultados pode se concluir que é viável a utilização dos resíduos estudados na confecção de pisos flutuantes para o isolamento do ruído de impacto
32

Kryty pracovního prostoru stroje / Protective Guards of Machine Tool

Zlámal, Josef January 2016 (has links)
The master thesis deals with the problematics of machine guard. The first part of the thesis is focused on the analysis of machine guards, legislative safety requirements and noise issues. The second part of the thesis describes design and construction of the machine guard in case of the vertical turning centre, TOSHULIN - POWERTURN 2000, including the calculation of noise reduction.
33

Träbjälklag med tung fyllning : Bjälklag framtaget med inspiration av byggteknik från sekelskiftet 1800–1900 / Timber floor with heavy filling : Floor developed with inspiration from building technique from the turn of the 19th century

Af Klintberg, Albin, Åkehag, Jonny January 2017 (has links)
Denna rapport utreder möjligheterna att använda restprodukter som ljudisolering i lägenhetsskiljande mellanbjälklag av trä med spännvidd 6 m. Ett steg mot att uppfylla Sveriges byggindustris nollvision för koldioxidutsläpp är att bygga mer i trä och att återanvända/återvinna restprodukter. Det svenska entreprenadföretaget Skanska har vid sina krossanläggningar ett överskott av material i form av bergkross 0 - 0,2 mm och krossad restbetong. I denna rapport har en prototyp av ett träbjälklag tagits fram med influenser från byggtekniken från sekelskiftet 1800–1900 med avseende på nyttjandet av tung fyllningsmassa som ljudisolering i träbjälklag. Den framtagna bjälklagsprototypen uppfyller de krav som ställts i BBR efter dimensionering enligt Eurokoderna med hänsyn till brand, hållfasthet, svikt och nedböjning. Enligt en simulering i SEAWood, ett verktyg för akustiksimulering som är under utveckling vid RISE Research Institutes of Sweden, uppfylls även kraven på ljudisolering, detta stöds av de analyser som gjorts av mätresultat från liknande bjälklag. Fyllningsmaterialets höga vikt medför att prototypen är ett lågfrekvent bjälklag, detta kombinerat med att simuleringen endast är en indikation på ljudisoleringsegenskaper gör att det kommer krävas praktiska tester för att fastställa prototypens ljudisolerande och dynamiska egenskaper. Den framtagna bjälklagsprototypen är lämplig att prefabricera tack vare en konstruktion med få ingående delar. Att prefabricera bjälklaget har utöver de ekonomiska fördelar det medför stora fördelar ur ett arbetsmiljöperspektiv och är även fördelaktigt ur fuktsynpunkt. För att uppskatta bjälklagets miljöpåverkan gjordes en enklare jämförelse med ett prefabricerat betongbjälklag som visade att utsläppen av koldioxidekvivalenter fram till bruksfasen var mer än dubbelt så stor för betongbjälklaget än för prototypbjälklaget. / This report investigates the possibilities of using residual products as sound insulation in apartment separating timber floors with a span of 6 m. One step towards meeting the Swedish construction industry's zero vision for carbon dioxide emissions is to build more using timber and to reuse/recycle residual products. The Swedish building contractor Skanska has at its quarries a surplus of material in the form of crushed rock of the 0 - 0.2 mm fraction and crushed residual concrete. In this report, a prototype of a timber floor has been produced with influences of construction technology from the turn of the 19 th century regarding the use of heavy filling as sound insulation in timber floors. The developed floor prototype complies with the requirements set in BBR after dimensioning according the Eurocodes regarding fire safety, strength, sagging and deflection. According to a simulation in SEAWood, a tool for acoustic simulation which is under development at RISE Research Institutes of Sweden the requirements for sound insulation are also met, which is supported by analyzes made by comparing with data on similar timber floors. The high mass of the filling material implies that the prototype is a low frequency floor, this in conjunction with the simulation only being an indication of sound insulation properties, it will require practical tests to determine the prototypes sound insulating and dynamic properties. The developed floor prototype is suitable for prefabrication thanks to a design with few components. Prefabrication of the floor has in addition to the economic benefits it brings great benefits from a working environment perspective and is also beneficial from a moisture point of view. To estimate the environmental impact of the timber flooring, a simple comparison was made with a prefabricated concrete floor which showed that carbon dioxide emissions up to the using phase were more than twice that of the concrete floor than for the prototype floor.
34

Metallfasern als schallabsorbierende Strukturen und als leitfähige Komponenten in Verbundwerkstoffen

Albracht, Frank 10 October 2004 (has links) (PDF)
Es werden metallische Kurzfasern, die durch ein Schnellerstarrungsverfahren direkt aus der Schmelze hergestellt werden, bezüglich ihrer Verwendung als hochporöser Absorber und als elektrisch leitfähige Strukturen in Verbundwerkstoffen vorgestellt. Auf der Basis einer schalldämpfenden hochporösen gesinterten Metallfaserstruktur und einer schalldämmenden Elastomerplatte wird ein neuartiges Schallschutzmaterial beschrieben. Die Theorie des homogenen Mediums ist für Absorber mit schichtartigen Aufbau erweitert und mit den gemessenen Absorberkennwerten verglichen worden. Weiterhin wird gezeigt, dass schmelzextrahierte metallische Kurzfasern in Polymerwerkstoffe eingelagert werden können, um einen elektrisch leitfähigen Faserverbundwerkstoff zu erhalten, der eine höhere Leitfähigkeit als rußgefüllte Polymere aufweist und eine preiswerte Alternative zu intrinsich leitenden Polymeren darstellt. Es werden die Herstellung und mechanische Eigenschaften des Metallfaserverbundwerkstoffes beschrieben. Das elektrische Verhalten des Faserverbundwerkstoffes wird anhand der Perkolationstheorie erläutert. Ausgehend von einem umfangreichen Überblick zu Möglichkeiten der Modellierung mechanischer und elektrischer Eigenschaften wird anhand geeigneter Modelle das reale Werkstoffverhalten beschrieben.
35

Polyfunkční dům / Multifunctional building

Novotný, David January 2014 (has links)
The main concern of this thesis work is the five-storey multifunction building. The house will consist of 22 residential units and one barrier-free apartment to which they belong cellar and two establishments. The building will have four above ground and one underground floor.
36

Metallfasern als schallabsorbierende Strukturen und als leitfähige Komponenten in Verbundwerkstoffen

Albracht, Frank 20 July 2004 (has links)
Es werden metallische Kurzfasern, die durch ein Schnellerstarrungsverfahren direkt aus der Schmelze hergestellt werden, bezüglich ihrer Verwendung als hochporöser Absorber und als elektrisch leitfähige Strukturen in Verbundwerkstoffen vorgestellt. Auf der Basis einer schalldämpfenden hochporösen gesinterten Metallfaserstruktur und einer schalldämmenden Elastomerplatte wird ein neuartiges Schallschutzmaterial beschrieben. Die Theorie des homogenen Mediums ist für Absorber mit schichtartigen Aufbau erweitert und mit den gemessenen Absorberkennwerten verglichen worden. Weiterhin wird gezeigt, dass schmelzextrahierte metallische Kurzfasern in Polymerwerkstoffe eingelagert werden können, um einen elektrisch leitfähigen Faserverbundwerkstoff zu erhalten, der eine höhere Leitfähigkeit als rußgefüllte Polymere aufweist und eine preiswerte Alternative zu intrinsich leitenden Polymeren darstellt. Es werden die Herstellung und mechanische Eigenschaften des Metallfaserverbundwerkstoffes beschrieben. Das elektrische Verhalten des Faserverbundwerkstoffes wird anhand der Perkolationstheorie erläutert. Ausgehend von einem umfangreichen Überblick zu Möglichkeiten der Modellierung mechanischer und elektrischer Eigenschaften wird anhand geeigneter Modelle das reale Werkstoffverhalten beschrieben.
37

Correlation between measured and perceived impact sound in schools

Burwall, Anton January 2022 (has links)
This project investigated the correlation between measured impact sound insulation and perceived walking sound annoyance in schools. The correlation was tested by performing standardized impact sound insulation measurements for different floor structures and comparing the measurement results with subjective perception of recorded walking for the same floor structures. Subjective perception of walking sound was evaluated by performing listening tests based on the recorded walking sounds. Five structures were tested, four different CLT structures and one concrete structure. The objective was to determine the significance of the frequencies below 100 Hz for perceived walking sound annoyance and to investigate whether the inclusion of frequencies below 100 Hz in the evaluation of impact sound insulation would improv the correlation between measured and perceived impact sound. The results from the listening tests showed that the rated walking sound annoyance for the structures did not correlate to the structures’ measured impact sound insulation. For example, the structure with the worst impact sound insulation was not rated the worst from the listening tests. Improvements to the correlation between measured and perceived impact sound were seen when the impact sound insulation was evaluated from 25 Hz, but the correlation was still not fully satisfactory.
38

AVALIAÇÃO DA PERDA DE TRANSMISSÃO SONORA EM PAREDES EXTERNAS DE LIGHT STEEL FRAME / EVALUATION OF SOUND TRANSMISSION LOSS IN LIGHT STEEL FRAME EXTERNAL WALLS

Radavelli, Graziella Ferrer 11 December 2014 (has links)
Environmental noise at high levels and inappropriate construction techniques used in conventional buildings in Brazil claim for a transition to better construction systems. Recently the Brazilian standard NBR 15575:2013 established for the first time parameters and criteria for residential building performance. In standard minimum requirements for sound insulation are given, for example for external walls and roof structures. This way it is of fundamental importance to have sound transmission loss data for diferente types of such elements at hand. Taking into account that there is very little information on the sound transmission loss of external walls of the light steel frame (LSF) type measurements of sound insulation of different vertical external LSF walls typically used in Brazil were carried out. Eighteen different LSF walls were mounted in the sound transmission measurement chamber of the Federal University of Santa Maria and measurements were carried out in accordance with ISO 10140:2010. Sound insulation was characterized by means of the sound reduction index R, the weighted sound reduction index Rw and the sound transmission class, making it possible to compare the sound insulation of the LSF walls with data from the literature. The LSF walls under investigation in this study used different materials such as OSB panels, cement boards, plaster boards, Smartside panels, PVC panels, XPS panels and magnesium oxide boards for the outer face. The influence of resilient channels and sponge tape, placed between the outer face and the metalic studes, were also evaluated. The sound insulation of the diferente LSF walls were found to be 43 dB ≤ Rw ≤ 50 dB and 45 dB ≤ STC ≤ 52 dB. Within the LSF walls measured the one which used magnesium oxide boards on the outer face showed to have the highest weight sound reduction index (Rw = 50 dB). Resilient channels, fabricated especially for this study, and sponge tape were able to provide an increase of Rw and STC up to 5 dB compared to the same wall without this resilient elements, and provide better sound insulation especially for frequencies higher than 400 Hz. From the data it can be concluded that LSF walls are more efficient regarding the sound insulation than single walls of the same surface mass and in some cases even better than single walls of superior surface mass, such as walls made of massive brick or concrete blocks. / O excesso de ruído ambiental e as inadequadas técnicas construtivas dos sistemas convencionais utilizados no mercado da construção civil brasileira, fazem com que seja necessária a introdução de novas tecnologias construtivas mais racionais e produtivas. A partir da entrada em vigor da NBR 15575:2013 foram estabelecidos diversos parâmetros de desempenho para edificações habitacionais. A referida norma também estabelece exigências mínimas de isolamento acústico para os sistemas que compõem as edificações, entre eles, as vedações verticais. Desta forma, informações sobre o isolamento acústico providenciado pelos diferentes sistemas construtivos tornaram-se de fundamental importância. Tendo em vista a pouca informação existente na literatura sobre o isolamento sonoro de paredes externas em light steel frame (LSF), foram realizadas medições de perda de transmissão sonora em paredes externas executadas neste sistema construtivo, usadas tipicamente no mercado brasileiro. Dezoito composições de paredes em LSF foram montadas na câmara reverberante de transmissão sonora da UFSM para realização dos ensaios de perda de transmissão conforme procedimentos propostos pela ISO 10140:2010. O isolamento sonoro foi quantificado a partir dos espectros do índice de redução sonora R, pelo índice de redução sonora ponderado Rw e pela classe de transmissão sonora STC, facilitando a comparação entre diferentes composições de parede e dados de isolamento sonoro encontrados na bibliografia. Os principais materiais utilizados no revestimento das paredes LSF foram paineis OSB, placas cimentícias, placas de gesso acartonado, réguas Smartside, réguas de siding vinílico, painéis XPS e placas de óxido de magnésio. A influência da utilização de barras resilientes e fitas de espuma de PVC, entre as placas de revestimento e a estrutura metálica, também foi avaliada. Determinou-se que o isolamento sonoro das diferentes paredes LSF avaliadas é de 43 dB ≤ Rw ≤ 50 dB e 45 dB ≤ STC ≤ 52 dB. Dentre as paredes externas em LSF, aquela que utilizou placas de óxido de magnésio na face exterior apresentou o maior Rw = 50 dB. As barras resilientes e fitas de espuma de PVC foram capazes de aumentar o Rw e STC em até 5 dB, se comparado à parede semelhante sem estes dispositivos, especialmente nas frequências a partir de 400 Hz. A partir da análise dos dados, concluiu-se que as paredes LSF consideradas paredes duplas são mais eficientes no isolamento sonoro quando comparadas às paredes simples ou homogêneas de mesma massa e até do que algumas paredes com massa muito superior, como paredes de tijolos maciços, de blocos de concreto ou de blocos cerâmicos.
39

Víceúčelový dům / The Multifunctional House

Pánek, Martin January 2014 (has links)
The main concern of this thesis is to design a five-storey multifunctional house. The house is divided into the main living area to which it belongs especially residential units accessible by stairs from the ground floor and also basement boxes and room for prams. On the ground floor are also located the individual garage, store room and technology. The house has four floors and a basement, the basement are located mass garages. The house has a sloping wooden roof trusses.
40

Mateřská škola / Kindergarten

Vystrčil, Patrik January 2014 (has links)
The master’s thesis on the topic Kindergarten is processed in the form of project documentation for the implementation of the new building. The building is designed on a plot of 1840/1 in the cadastral Brno - Husovice. It is the kindergarten with a basement and two floors. The building is brick, partial basement and roofing flat roof with single shell. The building contains two classes for a total of 40 children. Food and washing bedding is provided by imports.

Page generated in 0.1219 seconds