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No description available.

The purpose of this report was to investigate why insulation containing chlorofluorocarbon (CFC) is not always recycled correctly and examine if the supervision carried out by municipalities is enough to discourage erroneous handling. Additionally the purpose was to propose actions leading to that more insulation containing CFC is recycled and that municipalities can improve their supervision. The method used was a qualitative study where one questionnaire survey was sent to Swedish municipalities and one to demolition contractors. The results from the survey shows that 70 % of municipalities rarely carry out inspections on known demolition sites. This is mainly due to lack of resources but also due to not being aware of current demolition objects. Awareness is a primary condition for inspections. Often smaller municipalities are better informed which can be a consequence of better local knowledge. The survey shows that the material inventory, which is to take place before the application for demolition is filed, often is of a poor standard and lacks sampling for CFC. Lack of knowledge is pointed out as the main reason for incorrect handling of the material. Another reason is economy since identifying and taking care of hazardous waste is expensive. The level of knowledge needs to be increased among all affected parts and one way of doing so is to improve the cooperation and communication between different parts of the municipality so that more inspections can be conducted.

Diss. Stockholm : Handelshögsk. / Undertitel på omsl.: the case of replacing chloroflourocarbons.

Freoner är ett stort problem för människors hälsa och andra levande organismer på grund av freons nedbrytande effekt på ozonlagret. Forskare upptäckte problemen med freon och varningar från forskningssamhället uppmärksammades av huvudproducenter av freoner samt av allmänheten då påverkan på ozonlagret ökar risken för bland annat hudcancer. Montrealprotokollet blev starten på de internationella konventioner som senare implementerades. Dock finns det ett flertal växthusgaser idag som också är ozonnedbrytande som inte ingår under någon konvention. Den globala uppvärmningen är en effekt av ökad mängd växthusgaser i atmosfären och detta kräver ett internationellt samarbete för att kunna lösas. I Montrealprotokollet ingår ODS (Ozonnedbrytande substanser) där freon innefattas. Syftet för denna studie var att belysa vad som gjorde freonförbudet lyckat, och om det är möjligt att tillämpa dessa nyckelaspekter på en av dagens växthusgaser som liknar freon. NO2 valdes för att begränsa urvalet.  Denna litteraturstudie använde sig av databaser för att finna relevanta källor genom nyckelord, därefter valdes källor utefter relevansen till frågeställningen samt att de skulle vara opartiska. Resultatet av denna studie pekar på svårigheterna med att implementera det arbetssätt som ledde till freonförbudet, på gasen NO2, som hade liknande egenskaper som freon. Detta på grund av att dagens växthusgaser är svåra att reglera utsläppet på. Växthusgaser finns globalt och det finns inte en tydlig utsläppskälla som går att reglera samt hitta ett substitut för. Korrelationen till den mänskliga hälsan och miljön, är också en nyckelaspekt till varför förbudet mot freoner var lyckat. / Freons became a large problem for society when scientists proved the ozone depletion effect, which proved to have a negative effect on human health and other living organisms. The ozone layer which was known for its protective qualities against UV-radiation lead to a new field of study, ODS (ozone depleting substances). The warnings from the scientist society and the public were eminent. The research pointed out, among other things, the increasing risk of skin cancer. This forced fast new research and several international conventions to save the ozone layer. But there are several greenhouse gases, which also have the degrading effect on the ozone layer, that are in use today. This require an international cooperation for the environment to be able to solve. The aim of this report was to illustrate why the freon ban was a success and why it would be hard to implement these key concepts on a similar present greenhouse gas. In this literature study, several databases were used to find relevant sources for the main questions and unbiased for the topic. The key aspects in this study is presented in the result section. The result pointed at the difficulties with implementing the same way of work as at the freon ban to the greenhouse gas ban. Different aspects play an important role in this, but one of the greater difficulties for implementing this is to pinpoint it to a specific source for gas emissions and finding a sustainable solution for it. The correlation between human health and environmental issues was a key factor in the freon ban.

This work deals with the problem of pipeline plugging by gas hydrates during oil production. Gas hydrates are crystals resulting from water and gas molecules association under high pressure and low temperature conditions. Such thermodynamical conditions are generally encountered during oil production and transport, particularly in deep offshore fields or in cold areas. Due to an agglomeration process which is still debated, hydrate occurrence can lead to plug formation. This study aims at improving the understanding in this mechanism process, in the case of water-in-oil emulsions. Therefore, ice or hydrate particle agglomeration is compared. Ice or trichlorofluoromethane (CCl3F) hydrate particles dispersed in xylene with asphaltenes as surfactant is chosen as a model system. As CCl3F hydrates are stable under atmospheric pressure, it allows us to apply different techniques without being limited by high pressure conditions. The Nuclear Magnetic Resonance (NMR) technique is used. The very different relaxation rate for solids or liquids is used to monitor in situ the ratio between solid and total hydrogen or fluorine as a function of time with controlled shearing conditions. Thus, a kinetic study is realized, that enabled to know the amount of ice formed. The apparent viscosity of the system, during crystallization and plugging, is also followed with rheometry in order to characterize agglomeration. This experimental approach allows us to highlight that physico-chemistry of interface water/oil has an important role in agglomeration. It enables us to discuss different mechanisms of agglomeration of ice and hydrate particles in a hydrocarbon phase.

This thesis inquire into experimental decomposition of freon R-22 (CHClF2 - chlorodifluorometan) for different process conditions, by the help of pilot experimental unit in heavy laboratories DEPARTMENT of process and enviromental engineering Brno. This unit can decomposition waste gas, as the case may be combustion gas by the thermic oxidation or catalytic oxidation. Ground was in theoretical research, in which had been executed decomposition of freon R-22 in laboratory. In terms of experimental work were to be execution states for decomposition of freon R-22, next will be decomposition of freon R-22 by catalytic oxidation on catalyst Pt/Al2O3 and consequently this experiment will be analyse. Part of this thesis is exploration of facts basic way to decomposition of freon R-22, accounting of experimental unit and discussion of results.

Experimental data on SuperCritical-Water (SCW) cooled bundles are very limited. Major problems with performing such experiments are: 1) small number of operating SCW experimental setups and 2) difficulties in testing and experimental costs at very high pressures, temperatures and heat fluxes. However, SuperCritical Water-cooled nuclear Reactor (SCWRs) designs cannot be finalized without such data. Therefore, as a preliminary approach experiments in SCW-cooled bare tubes and in bundles cooled with SC modeling fluids can be used. One of the SC modeling fluids typically used is Freon-12 (R-12) where the critical pressure is 4.136 MPa and the critical temperature is 111.97ºC. These conditions correspond to a critical pressure of 22.064 MPa and critical temperature of 373.95ºC in water. A set of experimental data obtained in a Freon-12 cooled vertical bare bundle at the Institute of Physics and Power Engineering (IPPE, Obninsk, Russia) was analyzed. This set consisted of 20 cases of a vertically oriented 7-element bundle installed in a hexagonal flow channel. To secure the bundle in the flow channel 3 thin spacers were used. The dataset was obtained at equivalent parameters of the proposed SCWR concepts. Data was collected at pressures of about 4.65 MPa for several different combinations of wall and bulk-fluid temperatures that were below, at, or above the pseudocritical temperature. Heat fluxes ranged from 9 kW/m2 to 120 kW/m2 and mass fluxes ranged from 440 kg/m2s to 1320 kg/m2s. Also inlet temperatures ranged from 70ºC – 120ºC. The test section consisted of fuel elements that were 9.5 mm in diameter with the total heated length of 1 m. Bulk-fluid and wall temperature profiles were recorded using a combination of 8 different thermocouples.The data was analyzed with respect to its temperature profile and heat transfer coefficient along the heated length of the test section. In a previous study it was confirmed that there is the existence of three distinct regimes for forced convention with supercritical fluids. (1) Normal heat transfer; (2) Deteriorated heat transfer, characterized by higher than expected temperatures; and (3) Improved heat transfer, characterized by lower than expected temperatures. All three regions were observed for the 7 rod bundle experiments. This work compares the experimental data to predictions based upon current 1-D correlations for heat transfer in supercritical fluids. Results show that no current 1-D correlation was able to accurately predict heat transfer coefficients within ±50%. A parametric analysis of the data was also completed to determine if continuity in the experiment was present. Results of this study show that two distinct regions are present in the data. For cases with a mass flux below 1200 kg/m2s wall temperature profiles appear to be normal while in cases with mass flux above 1200 kg/m2s temperature given by the wall thermocouples were higher than normal. This phenomenon occurred regardless of heat flux-to-mass flux ratios. / UOIT

La matière sombre compte pour 85% de la matière composant l’univers et nous ne savons toujours pas ce qu’elle est. Depuis plusieurs années, l’expérience Picasso, maintenant devenue l’expérience PICO, tente d’élucider ce mystère. Les fréons de la famille des CXFY sont utilisés comme cibles de choix dans les détecteurs à liquides surchauffés de l’expérience PICO. Situés à SNOLab, en Ontario, ces détecteurs font parties des plus performant de la recherche de la matière sombre. Lors d’interactions de particules avec le liquide en surchauffe, un changement de phase est induit par le dépôt d’énergie engendré par l’interaction. Les bulles créées par l’évènement sont alors détectées par différents capteurs afin de déterminer le type d’interaction qui a eu lieu. Dans ce travail seront présentés les détecteurs à liquides surchauffés dans le cadre de la recherche de la matière sombre. Principalement, nous y verrons trois types de détecteurs utilisés par les expériences PICO et Picasso. Le principe de fonctionnement de chacun des détecteurs sera exposé en premier lieu ainsi que leur fabrication, puis leur mode d’opération et l’analyse des données. Les méthodes de calibration seront par la suite expliquées pour terminer avec une description des résultats obtenus démontrant la performance de ce type de détection. / Dark matter makes up 85% of the matter content of the universe and we still don’t know what it is made of. The Picasso experiment, now named PICO, has been searching for it for several years with the use of superheated liquid detectors. Following the interaction of a particle with a superheated liquid freon of the CXFY family, a bubble is formed through a phase change and is detected with several types of sensors, telling us about the nature of the event. Located at SNOLab, in Ontario, these detectors produce some of the best results in the field. The present work will go through three types of superheated liquid detectors. A full description of the working principles will be presented for each of them. In addition, the fabrication, the operation mode and the data analysis will be shown. Detector calibration techniques will then be presented with different particle sources. Finally, the most recent results will be discussed, demonstrating the performance of the superheated liquid detector technique.