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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.
11

Výskyt a interakce jodu v přírodním prostředí se zaměřením na hydrosféru. / The occurrence and interactions of iodine in a natural environment, focused on the hydrosphere.

ŠEDA, Martin January 2013 (has links)
Iodine is an important element essential for higher animals. A large part of the global human population suffers from a lack of iodine; elucidation of transfer and mobility of this element in the environment, water, soil, air and in organisms is thus very important. The aim of this work was the elaboration and optimisation of the method for determination of very low concentrations of iodine in the waters. The mass spectrometry with inductively coupled plasma (ICP-MS) technique was used. It has been shown that using of different filter types during sample preparation had no significant effect on the content of impurities in the filtered sample. Antimony was recommended as an internal standard, despite commonly used elements (indium or tellurium). Samples were not preserved because nitric acid caused volatilization of iodine from the sample and the addition of aqueous ammonia had no significant effect. The optimised method was tested on several groups of water samples, including precipitation, surface water and lysimetric waters. From autumn 2009 to summer 2010, a part of the Blanice River (Šumava Mountains, South Bohemia) was sampled. The average content of iodine in samples ranged from 1.48 ? 0.30 ?g?dm-3 (April 2010) to 3.05 ? 0.38 ?g?dm-3 (July 2010). The average content of iodine in samples from all tributaries of the Blanice River ranged between 2.52 ? 1.63 ?g?dm-3 (March 2010) and 3.67 ? 1.37 ?g?dm-3 (July 2010). The concentration of iodine in the monitored surface waters did not change significantly along the flow of the river. The other two streams were sampled near Rapotín village (Jeseníky Mountains, north Moravia). The average contents of iodine were as follow: Annov (upper stream) 1.60 ? 0.65 ?g?dm-3, Annov (lower stream) 1.88 ? 1.18 ?g?dm-3, Salaš (upper stream) 1.77 ? 0.92 ?g?dm-3, Salaš (lower stream) 1.42 ? 0.58 ?g?dm-3. Generally, the data showed that considering iodine, the area of Šumava had slightly higher levels than those observed in the Jeseníky Mountains. Precipitation collected in the South Bohemia (Arnoštov village and city of České Budějovice) and in Jeseníky (Rapotín) contained less iodine compared to surface waters, and rarely exceeded 3 micrograms per liter of water. The situation has changed in the spring of 2010, because of the occurrence of volcanic dust and ash over the Czech Republic. This volcanic cloud came from the sudden activity of the Eyjafjallajökull Volcano (Iceland). In the mentioned period, the contents of iodine in precipitation were increased several times at all sample collection sites. This is an indirect evidence that iodine could be released during volcanic eruptions and transferred over long distances through the atmosphere. It turned out that the wastewater treatment plant can eliminate iodine in wastewater only partially. However, the wastewater treatment plants in the monitored region were too small to evaluate the overall impact on the environment. The maximum iodine content at the outlet of the wastewater treatment plant Prachatice town (South Bohemia) was 28.5 ?g?dm-3, which is several times higher than natural levels in the Živný stream, to which the treated water flows. Lysimetric water samples were collected from lysimeters installed in three nearby plots in Arnoštov village (Šumava, South Bohemia). The highest concentrations of iodine were found on plot where cattle were grazed. These values were significantly higher (average 4.38 ? 1.74 ?g?dm-3) than those obtained from a site used as hay meadow (average 2.69 ? 1.19 ?g?dm-3) or an untreated meadow (average 2.25 ? 1.39 ?g?dm-3). Iodine therefore probably originated from the urine and feces of grazed cattle. This thesis contributes to the total knowledge of iodine, particularly to the part concerning determination of iodine in the hydrosphere.
12

Novel and ancient technologies for heating and cooling buildings

Amara, Sofiane January 2011 (has links)
The basic issue of this thesis concerns one of the fundamental problems of the future of our society: How to meet the energy requirements for a large and growing world population while preserving our environment? This question is important for the world and the answers are complex and interwoven.Conventional energy sources, fossil and fissile, are polluting in the present and in the future: they erode the environment and their resources are limited. Renewable energy (hydro, wind, solar, geothermal) constitutes a minimum of pollution in the different energy systems. The technologies for using renewable energy are well known though further development and progress are made. This development also requires behavioural change, adaptation, and above all political will. The transition from an economy based on fossil energy to an economy based on renewable energy appears necessary for the protection of the environment. The cost of renewable energy is often represented as an obstacle but remains competitive in the long run.The development and availability of renewable energy, which varies because of its spatial and temporal distribution, require an adaptation of lifestyle, habits, habitat design (passive bioclimatic houses), urban planning and transportation.The focus of this thesis was to apply renewable energy in an area with hot summers and cold winter, a climate like that in the northwest of Algeria. In order to provide improved comfort in the buildings and also economic development in this area, the energy demand for heating and cooling was analyzed in the ancient city of Tlemcen. To supply domestic hot water and space heating, water must be simultaneously available at two different temperature levels. Cold water temperature, close to that of the atmosphere, and hot water between 50 and 60°C. An interesting feature of the preparation of hot water is the small variation of requirements during the year, unlike that to heating. The preparation of hot water is one of the preferred applications of solar energy in the building for several reasons. For this reason an experimental study of the thermal behaviour of a domestic hot water storage tank was undertaken. The phenomena that affect the thermal behaviour of tank especially the coupling between the solar collector and storage tank was studied. This study included concentrating solar collector in which optical fibers were used to transport the energy to the storage tank. Another technology was introduced and developed for the heating and cooling of buildings in the desert involving an existing ancient irrigation system called Fouggara. The novel idea is to use the Fouggara as an air conditioner by pumping ambient air through this underground system. Then air at a temperature of about 21°C would be supplied to the building for heating in the winter and cooling in the summer. This study shows the feasibility of using this ancient irrigation system of Fouggara and contributes to reducing and eliminating the energy demand for heating and cooling buildings in the Sahara desert. / <p>Godkänd; 2011; 20110920 (sofama)</p>
13

Submicrometre aerosol emissions from sea spray and road traffic

Mårtensson, Monica January 2007 (has links)
<p>The uncertainty of the climate and health effects of aerosols is still large, one important reason being lack of knowledge of the primary emissions. This thesis combines laboratory and field experiments, and process modelling in an effort to better quantify the submicrometre aerosol emissions and to understand some of the processes in the atmosphere.</p><p>A parameterisation was derived for the source flux of sea salt particles (particles m<sup>-2 </sup>s<sup>-1</sup>) in the size range 0.02-2.8 µm dry diameter (D<sub>p</sub>), it is the first parameterisation to almost cover two full decades of the submicrometre sea salt aerosol production, and to include the effect of water temperature. This sea salt parameterisation was validated for temperate water in the 0.1-1.1 μm D<sub>p</sub> range using in situ size resolved emissions of marine aerosol particles, which were measured with the eddy covariance (EC) method. For periods sampled air was heated to 300ºC in order to evaporate semi-volatile organics and isolate the sea salt fraction. Comparisons with the total aerosol emissions suggest that in these emissions organic carbon and sea salt are internally mixed in the same particles. Finally an aerosol dynamics model was modified for marine conditions. In the model parameterised emissions of sea salt was included together with aerosol dynamics, chemistry and clouds representative for the marine boundary layer. The sea salt emissions are together with secondary sulphate, and cloud processing able to reproduce a typical marine aerosol size distribution and cloud condensation nuclei population.</p><p>Measurements with the EC method of the road traffic related aerosol source number flux for D<sub>p</sub>>0.011 µm show that the major part of the aerosol fluxes is due to road traffic emissions. Both an emission factor for the whole fleet mix in Stockholm (1.4x10<sup>14</sup> vehicle<sup>-1</sup> km<sup>-1</sup>) and separate emission factors for light- and heavy-duty vehicles (HDV) were deduced. The result shows that during weekdays 70-80% of the emissions come from HDV.</p>
14

Submicrometre aerosol emissions from sea spray and road traffic

Mårtensson, Monica January 2007 (has links)
The uncertainty of the climate and health effects of aerosols is still large, one important reason being lack of knowledge of the primary emissions. This thesis combines laboratory and field experiments, and process modelling in an effort to better quantify the submicrometre aerosol emissions and to understand some of the processes in the atmosphere. A parameterisation was derived for the source flux of sea salt particles (particles m-2 s-1) in the size range 0.02-2.8 µm dry diameter (Dp), it is the first parameterisation to almost cover two full decades of the submicrometre sea salt aerosol production, and to include the effect of water temperature. This sea salt parameterisation was validated for temperate water in the 0.1-1.1 μm Dp range using in situ size resolved emissions of marine aerosol particles, which were measured with the eddy covariance (EC) method. For periods sampled air was heated to 300ºC in order to evaporate semi-volatile organics and isolate the sea salt fraction. Comparisons with the total aerosol emissions suggest that in these emissions organic carbon and sea salt are internally mixed in the same particles. Finally an aerosol dynamics model was modified for marine conditions. In the model parameterised emissions of sea salt was included together with aerosol dynamics, chemistry and clouds representative for the marine boundary layer. The sea salt emissions are together with secondary sulphate, and cloud processing able to reproduce a typical marine aerosol size distribution and cloud condensation nuclei population. Measurements with the EC method of the road traffic related aerosol source number flux for Dp&gt;0.011 µm show that the major part of the aerosol fluxes is due to road traffic emissions. Both an emission factor for the whole fleet mix in Stockholm (1.4x1014 vehicle-1 km-1) and separate emission factors for light- and heavy-duty vehicles (HDV) were deduced. The result shows that during weekdays 70-80% of the emissions come from HDV.
15

Caractérisation des processus de transferts et d’interactions entre les compartiments hydrologiques, hydrogéologiques et cryosphériques d’un bassin versant andin semi-aride soumis à une forte variabilité climatique (Vallée de l’Elqui – Chili) / Characterization of water transfers and interactions processes between hydrologic, hydrogeologic and cryospheric compartments of an Andean, semi-arid watershed, affected by a strong climatic variability (Elqui Valley – Chile)

Pourrier, Jonathan 15 December 2014 (has links)
Le nord du Chili est soumis à un contexte climatique aride à semi-aride présentant une variabilité saisonnière et inter-annuelle forte. Dans cette région les zones de haute altitude soutiennent les parties plus basses des bassins versants, mais la ressource en eau reste malgré tout limitée. Afin d'améliorer les méthodes de gestion de l'eau dans ces bassins versants, il est important de préciser le rôle des zones de haute altitude dans le soutien des parties basses, mais aussi de caractériser les modalités de transfert et d'interaction entre les compartiments constitutifs de l'hydrosystème. Ce travail porte sur la caractérisation du fonctionnement hydrologique du bassin versant de l'Elqui depuis la tête de bassin, située au cœur de la cordillère des Andes, jusqu'aux vallées de la zone inférieure situées entre 500 et 2000 mètres d'altitude. En tête de bassin, les processus d'interaction entre les compartiments cryosphériques, hydrologiques et hydrogéologiques, et leurs impacts sur le transfert des masses d'eau vers l'aval de la zone d'étude sont caractérisés. Le comportement hydrologique des sous bassins versant partiellement ou non‑englacés est également étudié. Dans la zone inférieure du bassin, l'étude porte principalement sur les processus d'interactions surface-souterrain en contexte semi‑aride et sur les impacts des forçages climatiques et anthropiques sur ces derniers. Cette étude s'appuie sur plus de 40 ans de données hydro-météorologiques disponibles sur la zone inférieure du bassin, complétés par des mesures hydrologiques sur la zone supérieure (> 2000 mètres d'altitude) et des prélèvements chimiques (majeurs et traces) et isotopiques (²D, 18O) sur la totalité de la zone d'étude, réalisés entre 2011 et 2013.Ces travaux ont montré que le modèle conceptuel de fonctionnement du bassin versant de l'Elqui généralement accepté était incomplet. Dans la zone supérieure, l'étude d'un bassin versant englacé a permis de montrer que le rôle de la cryosphère dépasse la fonction de production d'eau, avec certains compartiments stockant temporairement de l'eau en période humide et la libérant en période sèche. Ce processus permet d'amortir la variabilité temporelle des précipitations et du taux de fonte en altitude. Les analyses physico-chimiques réalisées dans le bassin versant ont également permis d'identifier des compartiments aquifères ignorés jusqu'à maintenant, comme les compartiments volcanique et plutonique. En améliorant les connaissances sur les processus d'interactions entre compartiments cryosphériques, hydrologiques et hydrogéologiques, les résultats de ce travail ont apporté des précisions sur le fonctionnement hydrologique de la zone de haute altitude. Cela a permis l'estimation des impacts potentiels de la variabilité climatique sur ces processus d'interactions et leurs conséquences sur la disponibilité et la qualité de la ressource. Dans la zone inférieure, la caractérisation des interactions surface-souterrain a montré qu'il existe un fort potentiel d'interaction entre le compartiment hydrologique et le compartiment alluvial, mais également entre le compartiment alluvial et le socle plutonique. L'étude des données hydrologiques et physico-chimiques a permis de caractériser le type d'échanges se déroulant entre les compartiments. Dans certains secteurs le processus dominant est la recharge du compartiment alluvial par le compartiment hydrologique, tandis que pour d'autres il existe une alternance entre période de drainage du compartiment alluvial par le compartiment hydrologique et période de recharge du compartiment alluvial. La réponse de ces processus face aux impacts des forçages climatiques et anthropiques contraindra la disponibilité et la qualité de la ressource dans les années à venir. Ainsi, les résultats apportés par ce travail permettront certainement de mieux anticiper les modifications futures du fonctionnement hydrologique des bassins versant montagneux en contexte semi-arides. / The north Chile is affected by an arid to semi-arid climate, associated with a strong seasonal to inter-annual variability. In this region, while mountainous areas are supporting low areas, the availability of water resources remains limited. In order to improve the water management in these basins, it is necessary to precise how the high areas support the low areas, and to characterize water transfers and interaction processes between the constitutive compartments of the hydrosystem. This work concern the characterization of the hydrodynamic behavior of the Elqui watershed from the headwaters, in the Andes, to the valleys, ranging between 500 and 2000 m.a.s.l.In the headwaters, the interactions processes between cryospheric and hydrologic compartments and their impact on water transfers to the low areas are characterized. The behavior of unglacierized or partially glacierized watershed is also studied. In the low area of the watershed, the study mainly considers groundwater-surface water interactions under semi-arid context and the impact of the climatic variability on these processes. This study is based on more than 40 years of hydro-meteorological data available in the lower zone of the basin, completed by hydrological measurements in the upper zone (> 2000 m.a.s.l.) and chemical (majors and traces elements) and isotopic samples (²D, 18O) over the whole study area realized between 2011 and 2013.This work demonstrated that the conceptual model of the Elqui basin hydrological behavior, generally accepted, was incomplete. In the high area (> 2000 m.a.s.l.), the study of a glacierized watershed show that the function of the cryosphere overpass the water production with some compartments storing water during humid periods and draining their water content during dry periods. This process buffers the temporal variability of precipitations and melting rates in the high area. Physico-chemical analysis, allows to identify some ignored aquifer compartments, as the volcanic and plutonic compartments. The results of this study improve the knowledge about interactions processes between cryospheric, hydrologic and hydrogeologic compartments, which precise the hydrological functioning of the high area. The interpretation of the hydrological behavior of the high altitude area allows to better understand the way that it support the low area, and the way that climate variability may affects it.In the low area, results show that the groundwater-surface water interaction potential is good between alluvial and hydrological compartments, but also between the plutonic and the alluvial compartments. The study of hydro-meteorological and physico-chemical data allowed to characterize the type of exchanges that take place between groundwater and surface water. In some sectors the main process is the recharge of the alluvial compartment by the hydrological compartment, while in other sectors the processes show a seasonal variability with periods of alluvial compartment recharge and periods of hydrological compartment support. The answer of these processes face to climatic and anthropic forcing will constrain the evolution of the availability and quality of the water resources in the Elqui basin. Finally, the results of this study will certainly allow to better anticipate the future modifications of the semi-arid mountainous watershed hydrological functioning.

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