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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.
41

Identifying misconnection hotspots using coliforms and biofilm communities

Chiejina, Chidinma January 2016 (has links)
Sewage misconnections currently pose severe threats to water quality especially in urban areas in the UK. These misconnections lead to the discharge of untreated wastewater into receiving watercourses via surface water outfalls. Regular discharges from this source could lead to these watercourses failing to meet standards set by the Water Framework Directives. Despite the impacts resulting from this urban diffuse pollutant source, research into this area is limited. The study area is the River Lee, which is known to experience issues with water quality especially within the heavily urbanized lower Lee section. Misconnections are one of the major contributors to the poor water quality status of the River. In this study, the Lee was investigated using several parameters. The approach involved the monitoring of coliform bacteria to detect outfalls where misconnections were likely, then biofilm samples below selected outfalls were used for both clean and polluted sites to look for community types. Results showed severe pollution within some sections of the River particularly within the lower Lee. Pymmes Brook was used as a case study, both coliform bacteria and biofilm communities below outfalls were further investigated for clean and polluted sites. Results from the Pymmes Brook study also showed that this watercourse was experiencing severe issues with water quality, with elevated levels of coliform bacteria identified below polluted outfalls. Biofilm community data obtained during the pilot and experimental phases of study were analyzed using a range of multivariate techniques. Results of the analysis showed consistent x patterns in community structure within sites with similar water quality, with indicator species identified. Communities below polluted outfalls were composed mainly of species tolerant of organic pollution thus indicating a response of communities to misconnection discharges. Currently, the identification of misconnections are carried out through trackbacks, a process which is expensive and time consuming. During this study an inexpensive and rapid approach is proposed for assessing misconnections within a catchment. Using this method, misconnection hotspots are mapped out using coliform bacteria and biofilm communities. Using catchment data and predicted coliform bacteria from enumerated counts, misconnections within these hotspots are assessed. Having tested this approach on Pymmes Brook, a tributary of the River Lee, the results obtained were promising. Pending further verification, this system provides an economical and rapid tool for the assessment of misconnections within a catchment.
42

Flow Accelerated Corrosion Experience at Comanche Peak Steam Electric Station

Nakka, Ravi Kumar 05 1900 (has links)
Flow accelerated corrosion (FAC) is a major concern in the power industry as it causes thinning of the pipes by the dissolution of the passive oxide layer formed on the pipe surface. Present research deals with comparing the protection offered by the magnetite (Fe3O4) versus maghemite (γ-Fe2O3) phases thickness loss measurements. Fourier transform infrared spectroscopy (FTIR) is used in distinguishing these two elusive phases of iron oxides. Representative pipes are collected from high pressure steam extraction line of the secondary cycle of unit 2 of Comanche Peak Steam Electric Station (CPSES). Environmental scanning electron microscopy (ESEM) is used for morphological analysis. FTIR and X-ray diffraction (XRD) are used for phase analysis. Morphological analysis showed the presence of porous oxide surfaces with octahedral crystals, scallops and "chimney" like vents. FTIR revealed the predominance of maghemite at the most of the pipe sections. Results of thickness measurements indicate severe thickness loss at the bend areas (extrados) of the pipes.
43

Zdravotně technické instalace v hotelu s lázeňským provozem / Sanitation installation in a hotel with health resort

Šimon, Michal January 2014 (has links)
Thesis: Sanitation installation in a hotel with health resort The unit has 6 floors, it is partly with a cellar. The 1st floor is intended for spa purposes, the floors 3-5 serve as the acommodation area and in the 6th floor there is a machine room. The theoretic part is focused on the water problematics, on the type of sewages, including the labeling of their colors, and the following secondary use of the sewages. The next step is the choosing of the appropriate obtion. The project concerns the sanitation installation in a hotel with health resort.
44

Využití šedých vod v hotelu / Using of graywater in the Hotel

Výstupová, Eliška January 2016 (has links)
This thesis solves sanitary equipment installation and design of distribution of gray water in the hotel. Designed building has three floors and basement. On the first floor there are a restaurant, bar, conservatory, sanitary facilities and kitchen facilities. In the second and third floor are rooms for guests. In the basement there are storages, laundry room, engine room and other rooms, which are important for operation. The theoretical part is focused on familiarization with the theme of gray water, their division and possibilities. The practical part of applied knowledge on the subject at. The work also includes the calculation of return on this technological system.
45

Development of a virtual pipe test rig for testing acoustic correlators for leak detection in buried water pipes /

Iwanaga, Mauricio Kiotsune. January 2019 (has links)
Orientador: Michael John Brennan / Resumo: Vazamentos em tubulações de água enterradas são considerados um importante problema já que uma grande quantidade de água é desperdiçada entre a planta de tratamento e os consumidores. Para lidar com tal problema, companhias de saneamento utilizam dispostivos para localizar vazamentos nas tubulações. Dispositivos de escuta e correlacionadores de ruídos são os equipamentos mais utilizados em campo pelas companhias de sanemaneto ao redor do mundo. Correlacionadores de ruídos são dispositivos usados na localização de vazamentos em tubulações enterradas através da estimativa do tempo de atraso entre os sinais medidos pelos sensores posicionados em ambos os lados de um suposto vazamento. Uma vez que as companhias de saneamento devem decidir qual tipo de correlacionador é o mais compatível com a sua rede de tubulações, elas devem realizar alguns testes para ajudar em tal decisão e para treinar os funcionários que operam estes dispositivos, os quais devem ser expostos a diferentes condições, tais como tubos de diferentes materiais e geometrias, diferentes tipos de solo, vazamentos com diferentes intensidades, etc. Neste contexto, o principal objetivo desta pesquisa é contribuir com esta necessidade através da elaboração de um dispositivo de bancada capaz de reproduzir as vibrações de um tubo causadas por um vazamento. O dispositivo, chamado de simulador virtual de vazamentos, é composto por um computador, um amplificador de potência com dois canais e dois shakers. Ruídos de vazamento... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Leakage in buried water pipes is an important problem since a large amount of water is wasted between the treatment plant and the consumers. To deal with such a problem, water companies have used some devices to localize leaks in the pipe network. Listening devices and leak noise correlators are the most popular equipment used in the field by the water companies around the world. Leak noise correlators are important devices used to localize leaks in buried pipes by calculating the time delay between the signals measured by the sensors positioned either side of a suspected leak. Since water companies have to decide which leak noise correlator is more suitable for each pipe network, they have to carry out some field tests to assist in this decision and to train the personnel that handles such a device, which ideally must be exposed to different conditions, such as pipes with different materials and geometries, different types of soil, different leak strengths, etc. The main objective of this research project is to contribute with the necessity of the water companies by designing an indoor bench-top device capable to reproduce the pipe vibrations generated by a leak in the field. The device, called virtual pipe test rig, comprises a computer and a dual-channel power amplifier supplying two shakers. In the computer, leak noise is synthesized by using a model of a buried leaking pipe implemented using the software Matlab®. Since the systems, composed by the power amplifiers and th... (Complete abstract click electronic access below) / Mestre
46

Prediction of Turbulent Mixing at the Interface of Density Stratified, Shear Flows Using CFD.

Umbel, Matthew R. January 1998 (has links)
Thesis (Master').
47

Specifika komunikace v komunitě vodních dýmek na sociální sítích Facebook / The specifics of communication in hookah community on Facebook

Kopáček, Jakub January 2020 (has links)
This thesis deals with the topic of how the members of online community of hookah smokers (hookah community) communicate. The core of the thesis lies in the quantitative content analysis of the content published in three hookah community Facebook groups. The results of the analysis are complemented with insight gained through semi-structured interviews conducted with seven members of the hookah community, using qualitative analysis. The first part of the thesis outlines the new media, describes basic terminology and concepts of social networks and marketing communication, provides an introduction into the topic of online communities, and describes hookahs, the hookah community, and the commercial entities involved in the hookah industry. The second part of the thesis describes the methodology of quantitative and qualitative research, presents the obtained findings, and provides their summary utilizing the knowledge presented in the theoretical part of the thesis. The thesis aims to describe and evaluate the current state of communication within the hookah community Facebook groups and map the presence of commercial communication in the analyzed content.
48

Dimensionering av varmvattenavstick för att undvika Legionellatillväxt : En simuleringsstudie utförd i COMSOL Multiphysics​ / Dimensioning of hot water branches to avoid Legionella growth : A simulation study conducted in COMSOL Multiphysics​

Cedell, Olle, Ljunggren, Elias January 2020 (has links)
Bakterien Legionella pneumophila orsakar sjukdomen Legionella vilket har ökat i världen de senaste 20 åren och har troligtvis ett ännu större mörkertal. Den frodas i vattenrör mellan temperaturen 25–50 grader och vid installation av varmvattenrör i byggnader måste det tas hänsyn i riskzoner. Ett speciellt riskområde är varmvattenavstick som skapas för att kunna dra vidare vattenrör i framtiden. Där utsätts vattnet för större risk för stillastående och sjunkande temperaturprofil beroende på längd. Med hjälp av COMSOL Multiphysics® Modelling Software har ett teoretiskt ramverk för dimensionering av varmvattenavstick i byggnader skapats. Resultatet visar på hur stor strömningshastighet i vattenflödet, isoleringstjocklek och luftrörslängd har påverkan på hur långt avsticket kan vara utan att understiga kritisk temperatur. Resultatet kan användas som beslutsstöd givet att liknande avstickmodell och flödesprofil används samt om strömningshastighet i röret inte är längre än det i rapporten. / The bacterium Legionella pneumophila causes the disease Legionella which has seen an increase in the world over the last 20 years and likely has an even greater number of unrecorded cases. It thrives in water pipes between the temperature of 25-50 degrees and when installing hot water pipes in buildings certain factors must be taken into account. A special risk area is hot water branches that are created to be able to extend water pipes in the future. There, the water is at greater risk of stagnant and decreasing temperature profile depending on its length. With the help of COMSOL Multiphysics® Modelling Software, a theoretical framework for the dimensioning of hot water distances in buildings has been created. The result shows how the velocity in the water flow, the insulation thickness and the length of the air pipe have a great influence on how long the branch can be without falling below the critical temperature. The results can be used as decision support if one has a similar branch model and flow profile and also given a that a lower flow rate is not used.

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