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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

The qualitative and quantitative evaluation of estrogen and estrogen-mimicking substances in the South African water environment / Liesl van der Merwe

Van der Merwe, Liesl January 1998 (has links)
Recently some chemicals has been accused of mimicking the female hormone estrogen. The mode of action is termed estrogen-mimicking, because of the effects that is produced by these chemicals. Playing canary in a coal mine, wildlife was the first to indicate that something was wrong. Reproductive abnormalities such as abnormal sperm, reduced sperm production, cryptorchidism (undescended testes). abnormal hormone levels – particularly high estrogen ratios to that of testosterone. infertility, and genital abnormalities were all evidence that something in the environment was affecting the reproductive status of these animals. Also in humans instances like rising cases of infertility, abnormal sperm conditions and cases of breast cancer raised an increased concern about the potential disruptive effects of these substances on the human existence. After investigations were conducted, it was found that substances which enhance the quality of life like some detergents, agricultural products, additives to plastic, dyestuffs, paint components and pharmaceuticals to name but a few, all caused an abnormal reproductive status as seen in animals. The aims of this study were not to focus on the effect of these substances, but rather to identify estrogen and estrogen - mimics in the South African environment and to evaluate their presence in the water environment qualitatively and quantitatively with the most suitable analytical methods. Estrogen - mimics such as nonylphenol. o'p' and p'p' DDE, o'p' DDD, lindane, atrazine and the PCB's : Arochlor 1254 & Arochlor 1260 were found to contaminate the environment. The drinking water tested of the PWV area indicated that the water was free of these substances, and thus indicated a present safe situation. / Thesis (MSc (Farmaseutika))--PU for CHE, 1998
2

EMG analýza vlivu vodního prostředí na chůzi u starších osob / EMG analysis of the influence of the water environment on walking in the elderly

Vodičková, Kamila January 2015 (has links)
Title: EMG analysis of the influence of the water environment on walking in the elderly Objectives: The main objective of this master thesis is to determine the degree of activation of selected muscles during walking on land and in water environment by using surface electromyography. The next component objective is to determine and compare dynamic co-contraction level of low extremity muscles during walking on land and in water. Methods: It is a pilot study which was attended by 5 participants. The average age of the research group was 67,2 years and was represented 3 men and 2 women. Activity of m. tibialis anterior, m. gastrocnemius, m. rectus femoris, m. biceps femoris and mm. erectores spinae in the level of ThL transition was recorded during walking on land and in water environment. EMG signal has been adjusted, analyzed and after that normalized EMG signal to MVC was compared in both environments. The records were compared both intraindividually and interindividually. At the end dynamic co-contraction level of selected muscles was evaluated and compared during gait in both environments. Results: Electromyographic analysis revealed that during walking in aquatic environment were analyzed muscles involved with less extent than during walking on land. Co-contraction level was lower in low...
3

The qualitative and quantitative evaluation of estrogen and estrogen-mimicking substances in the South African water environment / Liesl van der Merwe

Van der Merwe, L. (Liesl) January 1998 (has links)
Thesis (MSc (Farmaseutika))--PU for CHE, 1998.
4

A Feasibility Test of Acoustic Tomography on Current Estimate in a Shallow Water Environment

Kuo, Nai-Tsung 03 August 2012 (has links)
Underwater communication is an important research of applied underwater acoustic since sound wave is the only effective way of transmitting messages under water. Underwater communication has always been a complicated problem especially in the shallow water environment due to the influence of multipath propagation. In the past, research on underwater communication had been done mostly by numerical simulation or laboratory experiments instead of doing in real oceanic areas. As a result, several research teams such as the Institute of Oceanography in Taiwan University, the Naval Research Laboratory and the acoustic laboratory of National Sun Yat-sen University Institute of Applied Marine Physics and Undersea Technology had executed a one-week real oceanic area experiment of underwater networking, communication, and acoustical tomography in Sizih Bay Marine Test Field. The experiment adopted 9 sets of underwater modem distributed within the range of 30 square kilometer to transmit, receive signals and collect CTD data. This research adopted part of the data gained from the experiment mentioned above to progress the feasibility test of acoustic tomography on current estimate to shallow water environment. By transmitting and receiving signals between stations, This research study the travel time difference between transmitting signals forward and backward caused by the flow field when using high frequency source in shallow water environment. This research estimated the average current speed and compared it to the weather buoy data from the Harbor and Marine Technology Center. This research discovered that most of the estimated results correspond to the weather buoy's ADCP data. Finally, this research adopted the method which does not require complex mathematics operation to estimate the two-dimensional flow field, and probe into what influence the angle between stations would bring to the deviation of estimating flow speed by using the Monte Carlo method.
5

Construction and Management of Water Environment for the Habitat of Wetland Parks in Urban Areas: A Case Study of Zhou-Zai Wetland Park, Kaohsiung, Taiwan

Chen, Fang-shuan 07 February 2006 (has links)
¡§Zhou-Zai Wetland Park¡¨ is a specific prototype of created wetland ecosystems constructed in urban areas, This park represents integration between development and preservation of a wetland habitat through ecotechnology. It is a created wetland designed to conserve the endangered species of Jacanas in Taiwan, which were suffered from the destruction of habitat in the past. The wetland comprises pool and marsh types of wetland systems, and the inflow of the systems is pumped from the Lian-Chih Lake. Several problems were found when we operated and managed the park including eutrophication, low water exchange rate, and hypoxia in some water areas, emergence, and invasive alien species. The current management strategies are difficult to improve the status. Therefore some suggestions are given to solve such problems including constructing a treatment wetland in injection area in order to improve the water quality of influent and then provide a better water environment of habitat for water fowls as well as to prevent the intrusion of invasive alien species.
6

The qualitative and quantitative evaluation of estrogen and estrogen-mimicking substances in the South African water environment / Liesl van der Merwe

Van der Merwe, Liesl January 1998 (has links)
Recently some chemicals has been accused of mimicking the female hormone estrogen. The mode of action is termed estrogen-mimicking, because of the effects that is produced by these chemicals. Playing canary in a coal mine, wildlife was the first to indicate that something was wrong. Reproductive abnormalities such as abnormal sperm, reduced sperm production, cryptorchidism (undescended testes). abnormal hormone levels – particularly high estrogen ratios to that of testosterone. infertility, and genital abnormalities were all evidence that something in the environment was affecting the reproductive status of these animals. Also in humans instances like rising cases of infertility, abnormal sperm conditions and cases of breast cancer raised an increased concern about the potential disruptive effects of these substances on the human existence. After investigations were conducted, it was found that substances which enhance the quality of life like some detergents, agricultural products, additives to plastic, dyestuffs, paint components and pharmaceuticals to name but a few, all caused an abnormal reproductive status as seen in animals. The aims of this study were not to focus on the effect of these substances, but rather to identify estrogen and estrogen - mimics in the South African environment and to evaluate their presence in the water environment qualitatively and quantitatively with the most suitable analytical methods. Estrogen - mimics such as nonylphenol. o'p' and p'p' DDE, o'p' DDD, lindane, atrazine and the PCB's : Arochlor 1254 & Arochlor 1260 were found to contaminate the environment. The drinking water tested of the PWV area indicated that the water was free of these substances, and thus indicated a present safe situation. / Thesis (MSc (Farmaseutika))--PU for CHE, 1998
7

Effects of wood ash on freshwater organisms and aquatic forest ecosystems /

Aronsson, K. Andreas. January 2007 (has links)
Diss. (sammanfattning) Sundsvall : Mittuniversitetet, 2007. / Härtill 4 uppsatser.
8

Quantifying the energy consumption of the water use cycle

Trujillo, Iliana Cardenes January 2017 (has links)
The management and delivery of water and wastewater consume significant amounts of energy, mostly in the form of electricity. With increasing populations, climate change, water quality issues and increasing energy prices, it is more important than ever to understand energy consumption patterns. Energy usually represents the largest operational cost in water utilities around the world, yet there is limited work aiming to quantify the specific relationship between water and its associated energy, and understand its implications for future decision-making. This thesis presents variousmethodological approachesto quantify and understand energy use in water infrastructure systems, as well as how to incorporate them in decision-making processes. The main hypotheses are as follows: firstly, a detailed understanding of the use of energy in water infrastructure systems can facilitate more efficient and sustainable water infrastructure systems and, secondly, that incorporating energy into planning for water and wastewater resources can help understand the impacts of decisions and establish trade-offs between actions. To test these hypotheses, the thesis presents an analytical approach to various areas. Firstly, it identifies, maps and quantifies the energy consumption patterns within a water infrastructure system. This is then used to identify inefficiencies and areas of potential energy saving. Secondly, it incorporates detailed energy costs into short and long-term water resources management and planning. Thirdly, it evaluates trade-offs between energy costs and changing effluent quality regulations in wastewater resources. The Thames River basin, in the south-east of England, is used as a case study to illustrate the approach. The results demonstrate that a systematic approach to the quantification of energy use in a water infrastructure system can identify areas of inefficiencies that can be used to make decisions with regards to infrastructure planning. For example, water systems have significant geo-spatial variations in energy consumption patterns that can be addressed specifically to reduce negative trade-offs. The results also show that incorporating detailed energy information into long-term water resources planning can alter the choices made in water supply options, by providing more complete information. Furthermore, methodologically, they show how several methodological approaches can be used to support more complete decision-making in water utilities to reduce short and long-term costs. In this particular case study, the results show that there are important differences in energy consumption by region, and significant differences in the seasonal and energy patterns of water infrastructure systems. For example, water treatment was shown to be the largest consumer of energy within the whole system, compared with pumping or wastewater treatment; but wastewater treatment energy consumption was shown to be the fastest growing over time due to changes in water quality regulatory frameworks. The results show that more stringent effluent standards could result in at least a doubling of electricity consumption and an increase of between 1.29 and 2.30 additional million tonnes of CO2 a year from treating wastewater in large works in the UK. These are projected to continue to increase if the decarbonisation of the electricity grid does not occur fast enough. Finally, the thesis also shows that daily energy consumption can be reduced by up to 18% by optimally routing water through a water network. optimization of water networks, and that a change in discount rates could change the daily operating costs by 19%, that in turn leads to a resulting different set of optimal investment options in a water supply network.
9

Fatigue oligocyclique d'un acier inoxydable austénitique 304L : influence de l'état de surface et de signaux de chargement en milieu eau primaire REP / Low Cycle Fatigue of a 304L Austenitic Stainless Steel : Influence of Surface Finish and Load Signals in PWR Water Environment

Poulain, Thibault 12 October 2015 (has links)
Le dimensionnement en fatigue des composants de centrales nucléaires prend en compte l’influence de nombreux paramètres tels que l’état de surface, les effets d’échelle, la variabilité du matériau, … Afin d’optimiser ce dimensionnement, il est nécessaire de comprendre le rôle joué par ces différents facteurs et d’identifier leurs interactions potentielles avec le milieu eau primaire REP (Réacteur à Eau Pressurisée). Dans cette étude, l’influence de l’environnement sur un acier inoxydable austénitique 304L en fatigue oligocyclique, mise en évidence par des essais conduits sous vide, dans l’air et en milieu eau primaire REP, est analysée en fonction de l’état de surface initial (état poli ou meulé) et de la nature du signal de chargement considéré (signaux triangulaires à différentes vitesses de déformation ou signaux complexes représentatifs de chocs thermiques successifs rencontrés en service). Une diminution de la durée de vie et l’accélération de l’endommagement provoquées par le milieu eau primaire REP ont été constatées quels que soient l’état de surface ou le signal de chargement considérés. L’influence néfaste de l’état de surface meulé sur les durées de vie en fatigue est mise en évidence puis expliquée par des essais interrompus à l’aide d’analyses qualitatives et quantitatives de l’endommagement. L’importance de la géométrie des fissures est révélée par des observations fractographiques et sa prise en compte au sein de lois de propagation permet d’expliquer la réduction de durée de vie liée à l’état de surface meulé. Enfin, l’influence dela forme du signal sur le comportement cyclique, l’endommagement du matériau et les durées de vie est détaillée. L’influence du positionnement des parties à faible vitesse de déformation au sein des cycles de chargement complexes est analysée en prenant en compte le temps d’exposition des fissures à l’environnement. / The fatigue design of Pressurized Water Reactor (PWR) components takes into account many parameters suchas the surface finish, the scale effects, the material variability, etc. To optimise this design, it is necessary tounderstand the role of those parameters and to identify their possible interactions with PWR waterenvironment.This work is focused on the low cycle fatigue behaviour of a 304L austenitic stainless steel in threeenvironments, namely vacuum, air and PWR water, through fatigue lifetimes, cracking mechanisms and crackgrowth characterisations. In addition, the roles of both surface finish (polished or ground) and load signal form(triangular signals with different strain rates or complex signals representative of successive thermal shocks)were investigated.The PWR water environment causes a fatigue life reduction and a crack propagation rate enhancement,regardless of surface finish or load signal shape. The deleterious effect of ground surface finish observed onfatigue life is explained by means of interrupted tests through qualitative and quantitative damage analysis. Theimportance of the crack geometry is revealed by fractographic characterisations and its integration inpropagation laws is used to account for fatigue life reductions induced by ground surface finish. Finally thesignal shape effects on cyclic behaviour, damage kinetics and fatigue life are discussed. The influence of theposition of the low strain rate parts within a complex cycle is analysed taking into account the time of crackexposure to the environment.
10

Hibernation of public space - an investigation of Stockholms water environment

Valek, Anton January 2021 (has links)
The project stems from a will to understand how I, as both a citizen and architect can partake in the creation and activation of the public water environment of Stockholm, a public sphere that I argue is largely in a state of hibernation. The main proposal is a multifunctional boat storage located at Pålsundet on Långholmen. With it I try to re-imagine the 25 hectares of centrally located plots designated to the winter storage of boats. The building strives to be an example of how to create a win-win solution where these plots could again become prime public space and year round meeting places whilst enhancing the cultural and social aspects of boat culture to more people.

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