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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.
51

Modeling of waste heat recovery system and outdoor swimming pool : Waste heat from hotel kitchen recovered by heat exchanger transferred to pool

Olanders, Linn January 2020 (has links)
This project was performed to evaluate if waste heat from hotel kitchens is enough to heat outdoor swimming pools in southern Europe or if it can be used as a compliment to another heat source. Another aim was to analyze the simulations and calculations of the pools and the heat recovery system. Then estimate how much annual costs would be reduced when using the exhaust air in the heat recovery system, in comparison with the original heating system. If the project showed positive results the purpose was to select a waste heat recovery system that can integrate with Ozonetech’s ozone generator, keep a high temperature in the pool and reduce emissions of greenhouse gas by using waste heat. Ozonetech would also conduct a pilot study in Stockholm and eventually develop their own product. A simulation model of three different outdoor pool sizes were conducted. The models were constructed and meshed in COMSOL Multiphysics. Average weather conditions for Malaga, Spain, were implemented in the model. The models were simulated by integrating each physical phenomenon in COMSOL, by using the Multiphysics interface. This created convection, emitted radiation and evaporation as thermal heat losses from the pool models. The pools were simulated to determine heating demand, heating period and required inlet temperature to make up for thermal heat losses. A mathematical model of the thermal heat losses and gains were conducted to easily receive a result for the heat demand each month of the year. A mathematical model of the possible heat recovery from hotel kitchens were performed to determine heat recovery for various kitchen sizes. By knowing the heat demand and possible heat recovery from different kitchens, a heat exchanger was selected. The heat exchanger was selected based on literature review, requirements and discussions with manufacturers. A life cycle cost analysis and calculated payback time compared original heating systems with new heat recovery system. A sensitivity analysis using Gauss error propagation concluded the project. The simulations showed that all investigated outdoor pools require additional heat during the night, due to extensive heating periods. Since the kitchen is only active during the day, the pool requires an additional heat source during the night. This conclude that the new heat exchanger only can replace the original heating system during the day. The mathematical model of the heat transfer from the kitchen determined that the maximum heat capacity approximately is 350 kW ± 10.5 kW. The waste heat can only be used to heat small and medium sized pools, since the heat loss is too great for a large pool. Selected air to water heat exchanger that meets the requirements is an air cooler with finned tubes from Alfa Laval. The fins and the coil should be treated to form an e-coat. After calculating the life cycle cost it was determined not profitable to replace a heat pump for a small pool, since the life cycle cost was greater for the new heating system. However, it is profitable to replace an electric heater with the new heat exchanger together with three of the smallest ozone generators during the day, for a small pool. Costs will be reduced by 44 600 – 202 000 kr ± 5%. Payback time will be 2.4 – 3.2 years ± 9%. It is also profitable to replace a water to water heat exchanger heated with either electricity or oil, during the day, with the new heat exchanger combined with either of the ozone generators for a small pool. Costs will be reduced by 310 000 – 698 000 kr ± 5%. Payback time will be 1.8 – 2.5 years ± 9%. It is profitable to replace all original heating systems during the day with the new heat exchanger combined with either of the ozone generators for medium sized pools. Costs will be reduced by 689 000 – 12 600 000 kr ± 5%. Payback time will be 2.2 – 22 months ± 7%.
52

Swimming pool water treatment with conventional and alternative water treatment technologies

Skibinski, Bertram 22 February 2017 (has links)
To mitigate microbial activity in swimming pools and to assure hygienic safety for bathers, pool systems have a re-circulating water system ensuring continuous water treatment and disinfection by chlorination. A major drawback associated with the use of chlorine as disinfectant is its potential to react with organic matter (OM) present in pool water to form potentially harmful disinfection by-products (DBP). In this thesis, the treatment performance of different combinations of conventional and novel treatment processes was compared using a pilot scale swimming pool model that was operated under reproducible and fully controlled conditions. The quality of the pool water was determined in means of volatile DBPs and the concentration and composition of dissolved organic carbon (DOC). Further, overall apparent reaction rates for the removal of monochloramine (MCA), a DBP found in pool water, in granular activated carbon (GAC) beds were determined using a fixed-bed reactor system operated under conditions typical for swimming pool water treatment. The reaction rates as well as the type of reaction products formed were correlated with physico-chemical properties of the tested GACs.
53

Optimalizace výuky plavání školních dětí / Training optimization of swimming of school-age children

Hudcová, Stanislava January 2011 (has links)
Subject matter: Training optimization of swimming of school-age children Objectives: The main goal of this research work is to suggest a model of advanced swimming training lessons with school-age children. Swimming training is practised in deep swimming pool. Next goal is to create an inventory of games and game disciplines which are suitable for training in deep water. Through the analysis of specialized literature and realization of experimental education we will be able to formulate new pieces of knowledge and introduce practical experience as a recommendation for practice. Method: The research work will observe swimming skills of school-age children within the advanced swimming training. The method of direct participant observation, measurement and scaling will be used. Results: Check on a model training we find out that advanced swimming trainning practised in deep water requires modifications of didactic methods of swimming skill training and swimming locomotion. Constant training of basic swimming skills, well- considered practises on a shore, motivational games and game disciplines are considered as the most important on the advanced swimming training. Key words: advanced swimming training, games, game disciplines, deep swimming pool/water, unsuitable swimming conditions
54

Postcolonial unions: the queer national romance in film and literature

Barron, Alexandra Lynn 28 August 2008 (has links)
Not available / text
55

An?lise da efici?ncia de aquecedor solar espiral com e sem efeito estufa para piscinas

Gon?alves, Joel Nogueira 03 February 2010 (has links)
Made available in DSpace on 2014-12-17T14:57:59Z (GMT). No. of bitstreams: 1 JoelNG.pdf: 2105058 bytes, checksum: 962e04f5bc007f4ee28c0e1f7973dece (MD5) Previous issue date: 2010-02-03 / The technical and economic viability of solar heating for swimming pools is unquestionable, besides there it replaces the high costs and environmental impacts of conventional supply of energy, and it improves an optimization in the pool heating uses. This work applies the principles of the greenhouse effect: advanced thermodynamics, heat retention and equalization of temperature, to optimize the solar heating equipment, reducing the area required by collectors as much as 40% (still estimated value) for commercial collectors, with minor architectural and aesthetic impacts on the environment. It features a solar heating alternative in pools, whose main characteristics: low cost, simplicity in manufacturing and assembly and a faster heating. The system consists of two collectors spiral hoses made of polyethylene with a hundred meters each, and working on a forced flow, with only one pass of the working fluid inside the coils, and is used to pump itself treatment of pool water to obtain the desired flow. One of the collectors will be exposed to direct solar radiation, and the other will be covered by a glass slide and closed laterally, so providing the greenhouse effect. The equipment will be installed in parallel and simultaneously exposed to the sun in order to obtain comparative data on their effectiveness. Will be presented results of thermal tests for this the two cases, with and without transparent cover. Will be demonstrated, by comparison, the thermal, economic and material feasibility of these systems for heating swimming pools. / A viabilidade t?cnica e econ?mica do aquecimento solar para piscinas ? inquestion?vel, al?m da substitui??o da energia el?trica convencional, de altos custos e impactos ambientais, gera uma otimiza??o do uso da piscina. Este trabalho aplica os princ?pios do efeito estufa: isola??o termodin?mica, reten??o do calor e equaliza??o da temperatura interna, busca otimizar o equipamento de aquecimento solar, reduzindo a ?rea requerida pelos coletores em at? 40% (valor ainda estimado) em rela??o aos coletores comerciais, com menores impactos est?ticos e arquitet?nicos que s?o negativos no ambiente. Apresenta um sistema solar de aquecimento alternativo em piscinas, que tem como principais caracter?sticas; baixo custo, simplicidade nos processos de fabrica??o e montagem e um aquecimento mais r?pido. O sistema ? constitu?do por dois coletores espirais constru?dos em tubos flex?veis de polietileno, com extens?o de 100 metros cada uma, e trabalha em regime de fluxo for?ado, com apenas uma passagem do fluido de trabalho no interior das espirais, e ? utilizada a pr?pria bomba de tratamento de ?gua da piscina para a obten??o do fluxo pretendido. Um dos coletores ser? exposto diretamente ? radia??o solar, e o outro ser? coberto por um lamina de vidro e fechado lateralmente, de forma propiciar o efeito estufa. Os equipamentos ser?o instalados em paralelo e expostos simultaneamente ao sol, de forma se obter dados comparativos de suas efici?ncias. Ser?o apresentados resultados t?rmicos de ensaios realizados para os dois casos, com e sem cobertura transparente. Ser?o demonstradas comparativamente, as viabilidades t?rmica, econ?mica e de materiais destes sistemas para aquecimento de piscinas.
56

Změny kvality vody v koupalištích ve volné přírodě a v koupacích oblastech v průběhu letní sezóny / Changes in water quality in outdoor swimming pools and swimming areas during the summer season

MARŠÁLKOVÁ, Alena January 2010 (has links)
Good quality of bathing water is an increasingly important factor taken into account when we choose summer vacations, a place to stay for a weekend or a weekend trip destination. In the Czech Republic, bathing waters may be divided according to the legal status into outdoor swimming pools, surface waters used for bathing (swimming areas), other water surfaces or artificial pools. In my thesis I dealt only with outdoor swimming pools and swimming areas. The difference between them lies in the fact that outdoor swimming pools have their own operators who monitor water quality and provide other services in the waterside. Usually there is a fee charged. Swimming areas have no operators and water quality monitoring is placed under the responsibility of regional public health authorities. In the Czech Republic, at present, 188 outdoor swimming pools and swimming areas have been monitored on a regular basis each bathing season. For my research I chose four sites located in the South Bohemian region and four sites in the South Moravian region. For each of these eight sites, I collected results of laboratory analyses, including categories of water quality in bathing seasons of the past five years, it means from the year 2005. With these obtained data I assessed the water quality development both during the bathing season of 2009 and its evolution over the past five years. On the basis of particular categories of water quality I also tried to compare water quality in the South Bohemian and the South Moravian region and also to compare water quality between individual sampling points in one locality. Another aim was to evaluate some measures and interventions made in order to improve water quality. I focused particularly on the pond Olšovec in the South Moravian region and the VN (water reservoir) Orlík in the South Bohemian region. The results do not show any prominent changes in water quality both during the bathing season 2009 and over the past five years. Pronounced fluctuations in water quality were recorded only at certain locations during the 2007 bathing season. Not even between individual regions significant differences in water quality were found. The proportion of individual water quality categories in the two regions did not differ by more than 4%. We can therefore say that water quality in selected localities in the South Bohemian and South Moravian regions is comparable. As for certain measures and interventions implemented to improve water quality, it is important to focus also on the wider neighborhood of the locality, because it could also be a source of substances worsening water quality.
57

Le management du risque de noyade dans les piscines publiques de la communauté d'agglomération Caen la mer : analyse organisationnelle et perspectives d’optimisation de la sécurité. / Drowning risk management in the public swimming pools of Caen la mer : organizational analysis and security optimization perspectives

Vignac, Élie 24 November 2017 (has links)
Malgré une surveillance constante exercée par les MNS, des noyades surviennent dans les PPAP. La thèse propose une analyse systémique et organisationnelle du risque de noyade dans ces équipements. Elle s'appuie sur une méthodologie qualitative plurielle : une analyse documentaire visant à quantifier le phénomène accidentel doublée de 9 entretiens d'experts (partie C), des observations de terrain menées dans 108 PPAP dans l'optique d'objectiver l'effectivité de la surveillance (partie D) et des entretiens semi-directifs afin de cerner les causes profondes des inadéquations : (n=27) à titre expérimental au sein d'une métropole du Grand-Ouest à l'occasion d'une mission d'expertise commanditée et (n=30) au sein de la communauté d'agglomération Caen la mer (partie E). Les résultats obtenus montrent que : 1) la production de données quantitatives sur la noyade en PPAP est entravée par un certain nombre de barrières faisant de cette question un « angle mort » de la connaissance ; 2) la surveillance exercée par les MNS est dégradée la moitié du temps d'observation et que 3) les arbitrages managériaux, la dynamique organisationnelle, mais aussi les représentations des acteurs interfèrent avec la fonction de surveillance, exerçant une influence sur sa réalisation et sa qualité. Les travaux mettent en évidence la coexistence et la redondance de boucles de rétroaction relativement efficaces mais peu coordonnées, articulées de manière contingente et inscrites dans différents registres. Aléatoire quant à son efficacité, la surveillance exercée par les MNS renvoie à une tâche difficile, fortement contrainte et de surcroît sujette à des formes plurielles d'adaptation. Ce travail montre que la gestion des risques dans ces équipements ainsi que les pratiques actuelles sont perfectibles. A ce propos, des recommandations à même d'optimiser la gestion des risques et la surveillance des bassins ont pu être formulées. Des actions préventives ont du reste été engagées (partie F) / Drownings occur in PSP (public swimming pool) despite lifeguard supervision.The thesis proposes a systemic and organizational analysis of the drowning risk in PSP based on a combined qualitative methodology : a documentary analysis aimed at quantifying the accidental phenomenon coupled with 9 expert interviews (part C), field observations conducted in 108 PSP in order to objectifying the effectiveness of supervision (part D) and semi-structured interviews to identify the root causes of mismatches : (n = 27) in experimental way for a Grand-Ouest metropolis within the framework of an expertise mission and (n = 30) within the Caen la mer community (part E). The results of the study show that : (1) the production of quantitative data on PSP drowning is hampered by several barriers that make this issue a “blind spot” of the knowledge ; 2) the supervision by lifeguard is degraded half of the observation time and 3) managerial arbitration, organizational dynamics, but also social representations of the actors interfere with the supervision function, exerting influence on its realization and quality. The work highlights the coexistence and redundancy of feedback loops that are relatively efficient but not coordinated, articulated in a contingent way and included into different registers. Monitoring by lifeguards, which is random about its effectiveness, refers to a difficult task, which is highly constrained and, moreover, subject to plural forms of adaptation. This work shows that the management of the drowning risks in these equipment and the current practices are perfectible. Moreover, recommendations were formulated to optimize risk management and pool supervision. Preventive action was also launched (Part F)
58

Contribution of organic UV filters to the formation of disinfection byproducts in chlorinated seawater swimming pools : occurrence, formation and genotoxicity

Manasfi, Tarek 22 September 2016 (has links)
La désinfection de l’eau de piscine est essentielle pour prévenir la propagation de maladies infectieuses. Cependant, les désinfectants réagissent avec les composés organiques présents dans l’eau y compris ceux introduits par les baigneurs, tels que les fluides corporels et les crèmes solaires, conduisant à la formation de sous-produits de désinfection (SPD) associés à des effets néfastes sur la santé. Le devenir des filtres UV organiques, présents dans les crèmes solaires et les produits de soins personnels, dans les piscines d'eau de mer chlorées est peu connu. Les objectifs de la présente étude étaient d'étudier la réactivité des filtres UV organiques dans l'eau de mer chlorée, d’identifier les SPD générées par les filtres UV, d'analyser l’occurrence des SPD dans les piscines d'eau de mer, et d'examiner leur génotoxicité. Des expériences de chloration ont été menées dans l'eau de mer reconstituée sur cinq filtres UV couramment utilisés : l’oxybenzone (OXY), le dioxybenzone (DIOXY), l’avobenzone (AVO), l’octyl méthoxycinnamate (OMC), et l’octocrylène (OC). Tous les composés étudiés sauf l’OC ont été dégradés conduisant à la formation de SPD bromés pour lesquels des schémas réactionnels ont été proposés. L'occurrence de ces SPD a été étudiée dans les piscines d'eau de mer où des SPD bromés ont été quantifiés. La génotoxicité de l’hydrate de bromal (BH), l’un des SPD généré par OXY et DIOXY et détecté dans les piscines d'eau de mer, a été évaluée. BH a induit une activité génotoxique dans le test d'Ames et l'essai de comète. Cette étude montre que les filtres UV peuvent agir comme précurseurs pour la formation de SPD génotoxiques dans l’eau de mer chlorée. / Disinfection of swimming pool water is critical to prevent outbreaks of infectious diseases. However, disinfectants react with organic compounds present in water, including anthropogenic inputs (e.g. body fluids, sunscreens), leading to the formation of disinfection byproducts (DBPs) that have been linked to adverse health effects. Little is known about the fate of organic UV filters, present in sunscreens and personal care products, when introduced into chlorinated seawater swimming pools. The aims of the present study were to investigate the reactivity of five commonly used organic UV filters in chlorinated seawater, identify DBPs generated from the UV filters, analyze the occurrence of these DBPs in seawater swimming pools, and examine their genotoxicity. Chlorination experiments were conducted to analyze the reactivity of the UV filters oxybenzone (OXY), dioxybenzone (DIOXY), avobenzone (AVO), octyl methoxycinnamate (OMC), and octocrylene (OC) in reconstituted seawater. All the studied UV filters except OC were degraded in chlorinated seawater resulting in the formation of brominated DBPs. Based on the identified byproducts, transformation pathways were proposed. The occurrence of the identified DBPs was investigated in seawater pools. Several brominated DBPs were identified in seawater pool samples. The genotoxicity of bromal hydrate (BH), which was generated by the benzophenone UV filters OXY and DIOXY and detected in the investigated seawater pools, was assessed. BH induced genotoxic activity in the Ames test and in the comet assay. Overall, this study shows that UV filters can act as precursors for the formation of genotoxic DBPs in chlorinated seawater pools.
59

Ocelová konstrukce plaveckého bazénu / Steel construction of the swimming pool

Sosna, Martin January 2020 (has links)
The thesis deals with the design and structural assessment of the swimming pool object in Dobruška. The solved structure has been chosen of the 2 preliminary variants. The dimensions of the rectangular floor plan are 34,10x40,99 m and the height of the ridge is 13,83 m. The structural system consist of two-hinged arched trusses which are connected with solid-web purlins and girts. The spatial rigidity is provided by combination of longitudinal and sway bracings. The cladding comprises of Kalzip roof system and a glass facade.
60

Dynamic Behavior Of Water And Air Chemistry In Indoor Pool Facilities

Lester Ting Chung Lee (11495881) 22 November 2021 (has links)
<p>Swimming is the second most common form of recreational activity in the U.S. Swimming pool water and air quality should be maintained to allow swimmers, pool employees, and spectators to use the pool facility safely. One of the major concerns regarding the health of swimmers and other pool users is the formation of disinfection by-products (DBPs) in swimming pools. Previous research has shown that volatile DBPs can adversely affect the human respiratory system. DBPs are formed by reactions between chlorine and other compounds that are present in water, most of which are introduced by swimmers, including many that contain reduced nitrogen. Some of the DBPs formed in pools are volatile, and their transfer to the gas phase in pool facilities is promoted by mixing near the air/water interface, caused by swimming and pool features.</p> <p><a>Swimming pool water treatment processes can play significant roles in governing water and air quality.</a> Thus, it is reasonable to hypothesize that water and air quality in a swimming pool facility can be improved by renewing or enhancing one or more components of water treatment.</p> <p>The first phase of the study was designed to identify and quantify changes in water and air quality that are associated with changes in water treatment at a chlorinated indoor pool facility. Reductions of aqueous NCl<sub>3 </sub>concentration were observed following the use of secondary oxidizer with its activator. This inclusion also resulted in significant decreases in the concentrations of cyanogen chloride (CNCl) and dichloroacetonitrile (CNCHCl<sub>2</sub>) in pool water. The concentration of urea, a compound that is common in swimming pools and that functions as an important precursor to NCl<sub>3</sub> formation, as well as a marker compound for introduction of contaminants by swimmers, was also reduced after the addition of activator.</p> <p>The second phase of this study involved field measurements to characterize and quantify the dynamic behavior of indoor air quality (IAQ) in indoor swimming pool facilities, particularly as related to volatile compounds that are transferred from swimming pool water to air. Measurements of water and air quality were conducted before, during, and after periods of heavy use at several indoor pool facilities. The results of a series of measurements at different swimming pool facilities allowed for examination of the effects of swimmers on liquid-phase DBPs and gas-phase NCl<sub>3</sub>. Liquid-phase NCl<sub>3</sub> concentrations were observed to gradually increase during periods of high swimmer numbers (<i>e.g.</i>, swimming meets), while liquid-phase CHCl<sub>3</sub> concentration was nearly constant in the same period. Concentrations of urea displayed a steady increase each day during these periods of intensive use. In general, the highest urea concentrations were measured near the end of each swimming meet. </p> <p>Measurements of IAQ dynamics during phase 2 of the study demonstrated the effects of swimmers on the concentrations of gas-phase NCl<sub>3 </sub>and CO<sub>2</sub>, especially during swimming meets. The measured gas-phase NCl<sub>3</sub> concentration often exceeded the suggested upper limits of 300 µg/m<sup>3</sup> or 500 µg/m<sup>3 </sup>during swimming meets, especially during and immediately after warm-up periods, when the largest numbers of swimmers were in the pool. Peak gas-phase NCl<sub>3</sub> concentrations were observed when large numbers of swimmers were present in the pools; measured gas-phase concentrations were as high as 1400 µg/m<sup>3</sup>.<sup> </sup>Concentrations of gas-phase NCl<sub>3</sub> rarely reached above 300 µg/m<sup>3</sup> during regular hours of operation. Furthermore, the types of swimmers were shown to affect the transfer of volatile compounds, such as NCl<sub>3</sub>, from water to air<sub> </sub>in pool facilities. In general, adult competition swimmers promoted more rapid transfer of these compounds than youth competition swimmers or adult recreational swimmers. The measured gas-phase CO<sub>2</sub> concentration often exceeded 1000 ppm<sub>v</sub> during swimming meets, whereas the gas-phase CO<sub>2</sub> concentration during periods of non-use of the pool tended to be close to the background (ambient) CO<sub>2</sub> concentration or slightly more than 400 ppm<sub>v</sub>. This phenomenon was largely attributed to the activity of swimmers (mixing of water and respiratory activity) and the normal respiratory activity of spectators. </p> <p>IAQ models for gas-phase NCl<sub>3</sub> and CO<sub>2</sub> were developed to relate the characteristics of the indoor pool environment to measurements of IAQ dynamics. Several assumptions were made to develop these models. Specifically, pool water and indoor air were assumed to be well-mixed. The reactions that were responsible for the formation and decay of the target compounds were neglected. Two-film theory was used to simulate the net mass-transfer rate of volatile compounds from the liquid phase to the gas phase. Advective transport into and out of the air space of the pool were accounted for. The IAQ model was able to simulate the dynamic behavior of gas-phase NCl<sub>3</sub> during regular operating hours. Predictions of gas-phase NCl<sub>3</sub> dynamics were generally less accurate during periods of intensive pool use; however, the model did yield predictions of behavior that were qualitatively correct. Strengths of the model include that it accounts for the factors that are believed to have the greatest influence on IAQ dynamics and is simple to use. Model weaknesses include that the model did not account liquid-phase reactions that are responsible for formation and decay of the target compounds. The IAQ model for NCl<sub>3</sub> dynamics could still be a useful tool to form the basis for recommendations regarding the design and operation of indoor pool facilities so as to optimize IAQ.</p><p>Measurements of CO<sub>2</sub> dynamics indicated qualitatively similar dynamic behavior as NCl<sub>3</sub>. Because of this, it was hypothesized that CO<sub>2</sub> may represent a surrogate for NCl<sub>3</sub> for monitoring and control of IAQ dynamics. To examine this issue in more detail, a conceptually similar model of CO<sub>2 </sub>dynamics was developed and applied. The model was developed to allow for an assessment of the relative contributions of liquid®gas transfer and respiration by swimmers and spectators to CO<sub>2</sub> dynamics. The results of this modeling effort indicated that the similarity of CO<sub>2</sub> transfer behavior to NCl<sub>3</sub> may allow use of CO<sub>2</sub> as a surrogate during periods with few to no spectators in the pool; however, when large numbers of spectators are present, the behavior of CO<sub>2</sub> dynamics may not be representative of NCl<sub>3</sub> dynamics because of spectator respiration.</p><p></p> <br>

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