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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

Formulation et propriétés d’une mousse utilisée dans l’amortissement de chute et de chocs dans le domaine de l’industrie du nucléaire / Formulation and properties investigation of foams used as shock absorber in the nuclear field

Mougel, Christophe 20 July 2018 (has links)
Les travaux présentés dans ce manuscrit ont été consacrés à la compréhension du procédé de fabrication des mousses phénoliques et de la chimie associée, dans le but de proposer des modifications de la formulation permettant l’amélioration de ses propriétés mécaniques (friabilité et comportement en compression). Dans un second temps, les propriétés mécaniques en compression, en flexion et la friabilité ont été caractérisées en fonction de la densité relative de la mousse. Les caractéristiques de compression ont été modélisées et comparées aux modèles de Gibson et Ashby. Les résultats montrent que le module d’Young et la contrainte au plateau de compression sont des fonctions quadratiques de la densité relative. Le comportement thermique de la mousse phénolique a été également étudié. L’évolution de la structure chimique des résidus obtenus après différents traitement thermique a été suivie par IRTF. Les observations spectrales ont été interprétées en fonction des réactions de dégradat ion proposées dans la littérature. Les paramètres cinétiques de dégradation de la mousse phénolique ont été déterminés grâce à différentes méthodes dites « model-free kinetic» développées par Flynn-Wall-Ozawa, Kissinger-Akahira-Sunose et Friedman. Finalement, dans une première approche, nous avons essayé de déterminer les paramètres cinétiques, en condition isotherme, du phénomène d’oxydation qui apparait à faible température / The following work has been devoted to the understanding of the phenolic foam manufacturing process and the associated chemistry, to propose modifications of the formulation itself that allows an enhancement in mechanical properties (friability and compression behavior). In addition, these mechanical properties in compression, bending and brittleness were characterized as a function of the foam relative density. Compression properties were modeled and compared to the Gibson and Ashby models. Results show that Young's modulus and collapse plateau stress are quadratic functions of the relative density. Moreover, the thermal behavior of the phenolic foam was also studied. The evolution of the chemical structure of the obtained residues after different thermal treatment was followed by FTIR. Spectral observations were interpreted according to the degradation reactions proposed in the literature. The kinetic parameters of phenolic foams degradation have been determined using different "mo del-free kinetic" approaches, developed by Flynn-Wall-Ozawa, Kissinger-Akahira-Sunose and Friedman. Finally, in a first approach, we tried to determine the kinetic parameters, in isothermal condition, of the oxidation phenomenon that appears at low temperature
2

Isoleringsmaterialets inverkan på energianvändning och klimatpåverkan : -En fallstudie

Håkans, Alexander, Östlund, Isaac January 2024 (has links)
Inom EU står byggnadssektorn för en hög andel av energianvändningen och medlemsländerna har satt upp mål för att minska energianvändningen. Målen som har fastställts i Sverige innebär att utsläppen av växthusgaser ska vara netto noll senast år 2045. I det här sammanhanget blir det extra viktigt att använda sig av tekniker som minskar CO2e-utsläppen och gynnar klimatet. En byggnads klimatskärm är en primär faktor till energianvändningen och det ställs höga krav på materialen som installeras i klimatskärmen. Det kommer i detta examensarbete utföras en fallstudie på en byggnad i Ljusne, Söderhamn. Här studeras tre olika isoleringsmaterial och två fönstertyper för att analysera deras påverkan på byggnadens energianvändning och för att ta fram det optimalaste alternativet ur ett klimatneutralt perspektiv. De material som studeras är mineralull, fenolskumskiva och termoträ samt vanligt fönster och passivfönster. För att besvara denna frågeställning utförs det energisimuleringar genom datorprogrammet BV2 samt beräkningar med materialens miljövarudeklarationer (EPD) för att analysera deras klimatpåverkan. Byggnadens klimatpåverkan beräknas med hjälp av byggsektorns miljöberäkningsverktyg (BM). I BM beräknas byggnadens utsläpp i koldioxidekvivalenter ut för renovering, energianvändning per år och under en livscykel på 50 år. Energisimuleringar utförda i BV2 visar att tilläggsisolering med fenolskum och fönsterbyte till passivfönster är den effektivaste metoden vid renovering av ytterväggen ur ett energieffektivt användningssätt. Då denna kombination har den lägsta energianvändningen, primärenergital och genomsnittlig värmegenomgångskoefficient. Det påvisar ett resultat med ett primärenergital på 72,5 kWh/m2 och en energianvändning på 116,8 kWh/m2. Men kombination av termoträ och passivfönster är den mest verkningsfulla på byggnadens klimatpåverkan. Detta illustreras i BM där klimatpåverkan för renovering är 2928,9 kg CO2e, energianvändning ger 3980,7 kg CO2e/år och klimatpåverkan för en livscykel på 50 år blir då 201 964 kg CO2e. Användningen av energisimuleringar gör att effektiva och klimatanpassade material kan studeras närmare för att avgöra dess betydelse. För att klimatmålen i Sverige och även EU ska kunna uppnås är behovet av verkningsfulla material väsentliga. Det här examensarbetet är en del i ledet mot ett klimatneutralt samhälle. / Within the European Union (EU), the building sector accounts for a high proportion of energy use and Member States have set targets to reduce energy use. The targets set in Sweden mean that greenhouse gas emissions should be net zero by 2045. In this context, it is particularly important to use technologies that reduce CO2 emissions and benefit the climate. A building’s envelope is a primary factor in energy consumption and high demands are placed on the materials installed in the climate screen. In this thesis, a case study will be carried out on a building in Ljusne, Söderhamn, Sweden. Three different insulation materials and two types of windows will be studied to investigate their impact on the building´s energy consumption and to find the most optimal alternative from a climate neutral perspective.  The materials studied are mineral wool, phenolic foam board and thermal wood, as well as ordinary windows and passive windows. To answer this question, energy simulations are carried out using the computer program BV2 and calculations on the materials environmental product declarations (EPD) to analyze their climate impact. The climate impact of the building is calculated using the building sector´s environmental calculation tool (BM). The BM calculates the building´s emissions in carbon dioxide equivalents for renovation, energy use per year and over a life cycle of 50 years.  Energy simulations performed in BV2 show that additional insulation with phenolic foam and window replacement with passive windows is the most efficient method for renovating the external wall from an energy efficiency point of view. As this combination has the lowest energy use, primary energy figure and average heat transfer coefficient. It demonstrates a result with primary energy figure of 72,2 kWh/m2 and an energy use of 116,8 kWh/m2. But the combination of thermal wood and passive windows is the most effective on the climate impact of the building. This is illustrated in BM where the climate impact for renovation is 2928,9 kg CO2e, energy use gives 3980,7 kg CO2e/year and the climate impact for a life cycle of 50 years is then 201 964 CO2e/kg. The use of energy simulations allows efficient and climate-friendly materials to be studied more closely to determine their importance. For the climate goals in Sweden and EU to be achieved, the need for efficient materials is essential. This thesis is part of the journey towards a climate-neutral society.
3

Vliv provedení zateplení administrativní budovy v Blansku na výdaje spojené s jejím provozem / The impact of executing new thermal insulation on an administrative building in Blansko on the expenses associated with its operation

Kopřivová, Petra January 2016 (has links)
The topic of the diploma thesis „ The impact of executing new thermal insulation on an administrative building in Blansko on the expenses associated with its operation“ is a draft and appraisal of four variants of thermal insulation of the building (EPS, EPS G, Mineral wool, Phenolic foam). It deals with an actual building situated in Blansko. All the variants are projected according to the same technical specifications (thermal transmittance) and their thermal parameters, technical parameters and the rate of return have been assessed. The assessed building (The A building) is at rectangular shape. It has six above - ground floors and a basement, it contains mainly administration sites. The construction system is concrete frame, which has curtain wall made of perforated blocks with thickness 250 mm. The building has got reinforced concrete floors, the roofing is made of double-skin roof construction. The supply for heating is a separate gas boiler room.
4

Vliv provedení zateplení bytového domu na výdaje spojené s provozem této nemovitosti / The impact of executing new thermal insulation on a apartment building on the expenses associated with its operation

Machová, Petra Unknown Date (has links)
The topic of the diploma thesis „The impact of executing new thermal insulation on a apartment building on the expenses associated with its operation “ is a draft and appraisal of four variants of thermal insulation of the building. The thesis deals with the assessment of the current proposal for apartment building envelopes along with proposing alternative plans with emphasis on reducing heating costs. The first section describes the types of buildings according to heating demand and a list of different variants of thermal insulation materials. The second part is devoted to a specific apartment building in the Ústí nad Labem for which there are designed in four variants of insulation. The work includes thermal assessment in original condition and the assessment of new condition modified by adding thermal insulation. Through research will bedetermined price of implementation of proposed insulation options together with the costs of operation of the apartment building. In conclusion, the diploma thesis evaluates the payback period of insulation.

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