Tesis:

1

Morell, Bonin Tyra. "Prestationsanalys av granulerataktivt kol (GAC) – en jämförelse mellan två etablerade GAC-typer". Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-328611.

Texto completo

Resumen

Vattenverket Görväln i Järfälla planerar ett nytt vattenverk i framtiden, lokaliserat intill nuvarande vattenverk. Idag är den kemiska barriären, granulerat aktivt kol, ur funktion och utvärderas i det här projektet för att effektivisera processen. Den här studien fokuserar på att optimera den kemiska barriären genom att jämföra två sorter av granulerat aktivt kol (GAC). Jämförelsen sker genom analysering av löst organiskt kol (DOC), totalt organiskt kol (TOC), samt absorbans och fluorescens. Vattnet som använts i studien kommer direkt från det sandfiltrerade vattnet i Görvälnverkets reningsprocess. För att testa de olika GAC-sorterna konstruerades en kolonnuppsättning med överflödessystem. Syftet var att jämföra två olika GAC med kortare samt längre uppehållstid och deras absorberingsförmåga med avseende på DOC och TOC. Kolonner med längre kontakttid visade effektivare borttagning av DOC, TOC och fluorescerande ämnen oberoende av GAC-sort. Kolonner med FiltraSorb® 400 uppnår genombrott ungefär 30 % långsammare än Norit® 830 W för samma bäddvolymer. Skillnaden mellan längre kontakttid och kortare kontakttid var inte lika markant som skillnaden mellan GAC-sorterna. FiltraSorb® 400 presterade ungefär 30 % bättre vid borttagning av DOC och TOC jämfört mot Norit® 830 W. Adsorptionskapaciteten för Norit® 830 W försämrades betydligt snabbare än för FiltraSorb® 400. Det innebär att FiltraSorb® 400 behöver bakspolas mindre ofta och regenereras mer sällan än Norit® 830 W. FiltraSorb® 400 är därför den GAC-sort som rekommenderas för Görvälnverkets vatten med avseende på borttagning av DOC. Den här studien kommer att användas som underlag för pilotanläggningen som är stationerad intill kolonnuppställningen. Uppsättningen kommer också att användas för framtida kinetik och spårämnesförsök i vattenverket och på andra vattenverk.
There are multiple steps to be done in the drinking water treatment process. The product must obtain high quality and to do so, it must reach certain requirements. One of the treatment steps in Görväln water treatment plant, Stockholm, is to use granular active carbon (GAC). The GAC function is to filter away taste and odor in addition to acting as a chemical barrier, although the latter does not work properly in the water treatment plant today.The project´s aim is comparing the performance of two types of GAC, Norit® 830 W and FiltraSorb® 400, together with the effect of longer (21 minutes) and shorter (7 minutes) contact time (EBCT). The contact time (EBCT) is the time, in minutes, that a body of water is in contact with the GAC-filter. A longer EBCT, means lower flow, which leads to longer time for the GAC to adsorb contaminants from the water.To evaluate the difference between the GAC-types a column-test was constructed. The test allows a direct comparison to full scale operations. The water used during this study was taken directly after the sand filtration process in Görväln. The water is clear and particles visible to the naked eye are eliminated during the sand filtration. However, the small dissolved organic components (carbon) are hard to remove, which makes the GAC-filter important.The performance of the GAC was evaluated by the removal efficiency of TOC, DOC and evaluation of fluorescence and absorbance capacity. The result indicated a better performance for both GAC using a longer contact time. Best effect of the long contact time was seen during the fluorescence measurement, where calculated indexes and removal of specific compounds were distinguished.The difference between longer, 21 minutes, and shorter, 7 minutes, contact time was not as significant as the difference between the two types of GAC. FiltraSorb® 400 had a significant higher adsorbance capacity for DOC and TOC, 30 % better than Norit® 830 W, at the same bed volume. Norit® 830 W reached breakthrough much faster (~80 %) than FiltraSorb® 400 (~50%) at around 4700 bed volumes.

Los estilos APA, Harvard, Vancouver, ISO, etc.

2

Tran, Thao Hoang. "Producing carotenoid-rich powder from Gac fruit". Thesis, View thesis, 2007. http://handle.uws.edu.au:8081/1959.7/19013.

Texto completo

Resumen

Gac (Momordica Cochinchinensis Spreng or Muricia Cochinchinensis Spreng) is an indigenous fruit of Vietnam, commonly used as a colourant in traditional dishes. Recent studies showed that this fruit had a high carotenoid content, especially lycopene and β-carotene. These carotenoids are currently in high demand as they are natural antioxidants to prevent and treat cancers. Over the last ten years some new products from Gac fruit have been found on the market but the cultivation and consumption of the fruit is still limited. Gac is harvested seasonally and the post harvest processing has not been well developed. To make the best use of the valuable substances in Gac, this project investigated some processing methods to make Gac powder and developed the product quality analyses, potentially applicable to local small-scale manufacture. In order to evaluate the efficiency of the Gac powder process and some of the most important qualities of the Gac powder products, the analytical methods to determine lycopene and β-carotene were developed and validated in this project. The new HPLC-based method included a liquid-liquid extraction, followed by a solid phase extraction before the analysis. Both newly- developed HPLC and SP methods exhibited a high extraction yield, good recovery and reproducibility. Compared with the HPLC, the SP method gives higher mean values and standard deviations, but it is quicker, simpler, less expensive and still reliable for industrial applications due to the use of less toxic solvents. The production of powder from Gac fruit included two main stages: seed removal and aril dehydration. Derived from the same drying operation, the enzymatic-treated Gac powder had a lower carotenoid content compared to the heat-treated powder. The Gac powder produced by the freeze-drying method had the highest carotenoid level and brightest colour. Finally the orange-red Gac powder with high carotenoid content was added to some foods as a colorant and nutrient supplement to illustrate its applications. The colours of foods were significantly improved and the carotenoid contents were increased after processing, indicating a potential market for the Gac powder.

Los estilos APA, Harvard, Vancouver, ISO, etc.

3

Tran, Thao Hoang. "Producing carotenoid-rich powder from Gac fruit". View thesis, 2007. http://handle.uws.edu.au:8081/1959.7/19013.

Texto completo

Resumen

Thesis (M.Sc.(Hons.)) -- University of Western Sydney, 2007.
A thesis submitted in fulfilment of the requirements for the degree of Master of Science (Hons) to the University of Western Sydney, College of Health and Science, Centre for Plant and Food Science. Includes bibliography.

Los estilos APA, Harvard, Vancouver, ISO, etc.

4

Janeiro, Hugo. "Redes Internas do GAC. Alterações decorrentes da implementação do SACC". Master's thesis, Academia Militar. Direção de Ensino, 2013. http://hdl.handle.net/10400.26/7546.

Texto completo

Resumen

O presente trabalho tem como objetivo analisar as Redes Internas do Grupo de Artilharia de Campanha (GAC), da Brigada de Reação Rápida (BrigRR), e a implementação do Sistema Automático de Comando e Controlo (SACC) nesta unidade. No Exército Português, e para fazer face ao ambiente operacional contemporâneo, foi adquirido o SACC para a Artilharia, pelo que se tornou necessário efetuar uma investigação no sentido de verificar se são necessárias alterações e quais as que devem ser feitas ao nível das Redes Internas do GAC/BrigRR, decorrentes da implementação do SACC. Para a elaboração deste trabalho, começamos por caracterizar o ambiente operacional contemporâneo e as consequentes novas exigências para a Artilharia de Campanha (AC). De seguida, realizou-se o estudo das capacidades e necessidades para a implementação do SACC e seus subsistemas, e explanamos as várias fases da implementação do SACC no GAC/BrigRR, desde a sua aquisição até aos dias de hoje. Realizou-se também o estudo, ao nível das Redes Internas de um GAC, primeiramente da doutrina portuguesa e da doutrina americana, que decidimos expor como referência. Numa segunda fase, foi feita uma pesquisa, que engloba especificamente o GAC/BrigRR, no que diz respeito ao seu Quadro Orgânico doutrinário e à sua situação atual, relativamente aos materiais utilizados no processo de Comando e Controlo (C2) do GAC. Esta pesquisa teve o intuito de explicitar as capacidades de cada material e uma relação entre a quantidade e tipo de materiais previstos em Quadro Orgânico e a quantidade e tipo de materiais que realmente estão à carga do GAC/BrigRR. Este estudo permitiu ainda analisar a configuração e operacionalização das Redes Internas do GAC/BrigRR, de modo a verificar se a sua organização atual necessita de alterações, que permitam cumprir as suas missões, tendo em vista a maximização das capacidades do SACC em prol do GAC/BrigRR. Desta análise concluiu-se que a organização atual das Redes Internas do GAC/BrigRR não permite corresponder às exigências do SACC, tanto ao nível da configuração das redes como também dos materiais utilizados, o que inviabiliza a maximização das potencialidades do sistema no GAC/BrigRR. Apesar das limitações encontradas nas Redes Internas do GAC/BrigRR, a anterior análise possibilitou efetuar o levantamento e posterior análise, de possíveis configurações de redes a adotar pelo GAC/BrigRR.
Abstract This paper aims to analyze the Internal Networks for the Field Artillery Battalion, from the Quick Response Brigade, and the implementation of the Automated System for Command and Control on this unit. In the Portuguese Army, and to cope with the contemporary operatin g environment, was acquired the Automated System for Command and Control for Field Artillery, so it became necessary to make a research to see if changes are needed and what changes should be made at the level of Internal Networks for the Field Artillery Battalion from the Quick Response Brigade, following the implementation of SACC. For the preparation of this work, we first characterize the contemporary operating environment and the resulting new requirements for the Field Artillery. Then follows the study of the capabilities and requirements for implementation of the Automated System for Command and Control and its subsystems, and expounded the various stages of implementation of the Automated System for Command and Control in the Field Artillery Battalion since its acquisition until the present day. We also conducted the study at the level of an Internal Networks for the Field Artillery Battalion, first the Portuguese doctrine and then the American doctrine, that we decided to expose as a reference. In a second phase, a survey was made, which specifically includes the Field Artillery Battalion, in regard to their doctrinal Organic Framework and its current situation, referring to the equipments used in the process Command and Control of the Field Artillery Battalion. This research aimed to explain the capabilities of each equipment and a relationship between its amount and type provided in Table Organic and the quantity and type that are actually available for the Field Artillery Battalion. This study allowed us to analyze the configuration and operation of the Internal Networks for the Field Artillery Battalion, to check if its current organization needs changes, allowing the fulfillment of their missions in order to maximize the capabilities of the Automated System for Command and Control on behalf of the Field Artillery Battalion. This analysis concluded that the current organization of the Internal Networks for the Field Artillery Battalion does not allow to match the requirements of the Automated System for Command and Control, both in terms of the configuration of the networks as well as the materials used, which prevents the maximization of the potential of the system in the Field Artillery Battalion. Despite the limitations found in the Internal Networks for the Field Artillery Battalion, the previous analysis allowed to make the survey and subsequent analysis of possible network configurations to be adopted by the Field Artillery Battalion from the Quick Response Brigade.

Los estilos APA, Harvard, Vancouver, ISO, etc.

5

Zheng, Jing. "Application of GAC adsorption in pulp and paper mill effluent treatment". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0019/MQ58522.pdf.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

6

De, Las Casas Carla. "In-Situ Regeneration of Granular Activated Carbon (GAC) Using Fenton's Reagents". Diss., The University of Arizona, 2006. http://hdl.handle.net/10150/195619.

Texto completo

Resumen

Fenton-dependent recovery of carbon initially saturated with one of several chlorinated aliphatic contaminants was studied in batch and continuous-flow reactors. A specialty carbon, URV-MOD 1 (Calgon) was employed to minimize non-productive H2O2 demand - that which does not yield hydroxyl or superoxide radicals.Enhancement of PCE degradation kinetics by ferric iron addition is limited by iron solubility, even at relatively low pH. Quinone addition increased the pseudo-first-order rate constant for PCE loss temporarily. Only copper addition sustainably enhanced the specific rate of PCE loss. For copper-to-iron molar ratios of 0.25 to 5, the pseudo-first-order rate constant for PCE transformation was increased by a factor of 3.5. It is apparent that the effect of copper addition on Fenton-dependent reaction rates is complex, and involves a shift in chemical mechanism, as indicated by the differing slopes in the Arrhenius plot (with and without copper).A mathematical model was developed to evaluate the effect of operational parameters ([Fe(III)]T:[H2O2]o ratio and pH) on degradation kinetics and optimize the PCE degradation process in homogeneous reaction mixtures. The model simulated experimental degradation of the organic target in a homogeneous Fenton-reaction system. The model requires further refinement to simulate Fenton's systems in which ions in solution (such as sulfate and chloride) play significant roles.In continuous-flow reactors, Fenton's reagents were cycled through spent GAC in columns to degrade one of seven chlorinated compounds tested. The contaminant with the weakest adsorption characteristics, methylene chloride, was 99% lost from the carbon surface during a 14-hour regeneration period. At the field site, the GAC was saturated with gases containing TCE and PCE from a soil vapor extraction (SVE) system. In the field, up to 95% of the sorbed TCE was removed from GAC during regeneration periods of 50-60 hours. Recovery of PCE-loaded GAC was significantly slower. Column experiments show that there is minimal loss of carbon adsorption capacity during Fenton treatment and that the rate of GAC regeneration is compound specific. Scoping-level cost estimates indicated that field use of Fenton regeneration is not cost effective without optimization and/or iron surface amendments, except in the case of the most soluble VOCs.

Los estilos APA, Harvard, Vancouver, ISO, etc.

7

Rentsch, Stefanie. "Hybrides Erzählen Text-Bild-Kombinationen bei Jean Le Gac und Sophie Calle". Paderborn München Fink, 2008. http://d-nb.info/993984967/04.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

8

Chen, Bingran. "Effects of Chemical Properties of Cyanotoxins on Transport through Granular Activated Carbons". University of Cincinnati / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1535374137804276.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

9

Al-Attas, Omar. "Competitive Adsorption of Iron and Natural Organic Matter in Groundwater Using Granular Activated Carbon". Thèse, Université d'Ottawa / University of Ottawa, 2012. http://hdl.handle.net/10393/23349.

Texto completo

Resumen

The treatment of potable water in Vars, ON is accomplished by filtering the colored, iron-laden groundwater through granular activated carbon (GAC) filters. When first installed, these filters unexpectedly experienced chromatographic displacements of iron into the produced water which resulted in orange-brown water at consumers’ taps. The treatment plant was later modified by adding potassium permanganate oxidation and a greensand filter prior to the GAC adsorption columns. Consequently, iron was almost completely removed and no longer caused operational problems. The main objective of this dissertation is to study the interactions between natural organic matter (NOM) and iron that caused the observed chromatographic effect. This study was divided into three main stages: a) characterization study on Vars groundwater and its treatment system; b) study of the competitive adsorption of iron with NOM in Vars groundwater; and c) evaluation of the rapid small-scale column test (RSSCT) for predicting the full-scale GAC column breakthroughs. The characterization of Vars groundwater showed that ferrous iron was found to be the dominant iron species, representing 90% of the total iron, and that 15 - 35% of the iron was complexed with NOM. It was hypothesized that the chromatographic displacement of iron from the GAC columns was caused by NOM-iron complexes; however, field mini-column experiments showed this was not the case. Thus, competitive adsorption between iron and NOM was seen as the more likely cause of the chromatographic effect. The adsorption capacity of ferrous iron in Vars raw water was less than that in organic-free water by a factor of 7 due to the competition with NOM over the GAC adsorbing sites. However, the NOM adsorption capacity was not reduced due to the presence of ferrous iron. It was hypothesized that ideal adsorption solution theory (IAST) models, which have been successful in describing competitive adsorption between target organic compounds and NOM, could model the competition between an inorganic compound such as ferrous iron and NOM. The hypothesis was proved to be correct, and the adsorption isotherm of iron in competition with NOM in Vars groundwater was simulated very well by several versions of the IAST model. However, none of the models were capable of simulating the competitive adsorption of NOM and ferrous iron simultaneously. Since the presence of iron did not significantly reduce the adsorption capacity of NOM, a simplified approach of using the single-solute NOM isotherm to represent the competitive NOM isotherm was recommended. The performance of the rapid small-scale column test (RSSCT) was evaluated in order to simulate the iron chromatographic effect observed at Vars’ full-scale GAC column. The RSSCT was not capable of predicting the iron phenomenon and the test proved to be problematic due to the oxidation and precipitation of iron within the small voids between the small-scale column’s GAC particles. The RSSCT, using constant and linear diffusivities, were applied to simulate the NOM adsorption after greensand treatment. Integrating both diffusivities, the tests predicted the onset and slope of the NOM breakthrough up to 10-L water treated/g GAC, which is equivalent to 250 days of operation time for the full-scale column. However, the NOM breakthroughs deviated beyond that point and the RSSCT using constant diffusivity underestimated the column performance greatly. On the other hand, the linear diffusivity RSSCT underestimated the performance to a lesser degree and its NOM breakthrough was quite parallel to the full-scale performance with lower NOM removals of 15%. The higher long-term NOM removal in the full-scale system may be explained by biodegradation, a phenomenon that was not considered by the short duration of RSSCT.

Los estilos APA, Harvard, Vancouver, ISO, etc.

10

Godinho, Carlos. "A organização topográfica do GAC face aos novos equipamentos topográficos da Artilharia de Campanha Portuguesa". Master's thesis, Academia Militar. Direção de Ensino, 2008. http://hdl.handle.net/10400.26/7282.

Texto completo

Resumen

No âmbito do Estágio de Natureza Profissional do Tirocínio para Oficial Aluno da Arma de Artilharia (TPO), nomeadamente na componente do Trabalho de Investigação Aplicada, escolheu-se como tema de investigação a rganização topográfica do Grupo de Artilharia de Campanha (GAC) face aos novos equipamentos topográficos da Artilharia de Campanha (AC). Tendo em conta a permanente evolução tecnológica e o reequipamento do Exército Português como uma etapa de um ciclo contínuo que visa o acompanhamento dessas transformações e a adaptação às necessidades de um moderno campo de batalha, surge o interesse em saber como está a sua vertente topográfica. È desta forma que abordamos e pretendemos dar a conhecer os novos equipamentos topográficos adquiridos pelo Exército Português. De igual modo, foi nosso objectivo perceber até que ponto houve ou deverá haver alterações na organização topográfica e na execução dos trabalhos topográficos de um GAC. Julgámos ainda ser possível indicar, com base nos relatos dos militares que desempenharam ou exercem funções que implicam o relacionamento directo com os equipamentos, situações úteis para complementar a doutrina topográfica existente na AC. Os resultados obtidos demonstram que a aquisição e a utilização destes equipamentos topográficos são enormemente proveitosas para a nossa AC e para as outras Unidades que dos seus trabalhos necessitem. O desempenho da missão topográfica passou a ser mais rápido e oportuno, a informação topográfica passou a ter mais qualidade e quantidade, os novos equipamentos garantem ao GAC uma maior flexibilidade e oportunidade na ocupação das posições e contribuem para a execução de eficácias ao primeiro tiro. Quanto à organização topográfica do GAC, houve uma redução nos efectivos, consequente das menores exigências de pessoal no funcionamento destes equipamentos, perante a qual se tem cumprido a missão topográfica nos exercícios mas não com a máxima potencialização dos meios. É, sobretudo, com base neste factor que apresentamos uma proposta para a organização da “célula” de topografia do Exército Português, a Secção de Topografia.
Abstract The subject of this inquiry is the training and professional period of the apprenticeship for Official student in the Artillery. We will look at the survey structure of a Field Artillery Battalion and report on the new survey instrument of the Field Artillery. We need to take into account the continuing technological evolution and the updating of the equipment of the Portuguese Army as one phase of a continuous cycle. This aims to serve the Army’s needs in the modern battlefield. We intend to give information concerning the new survey equipment, acquired by the Portuguese Army. Our objective also includes an appreciation of any changes in the survey structure which have been made, or will need to be made in the survey operations of a Field Artillery Battalion. We have interviewed military professionals who have had practical experience of the equipment, and were able to provide helpful comments about the Field Artillery Survey equipment and procedures. The results obtained show that the acquisition and the use of these survey instruments are very beneficial to our Field Artillery and to otherunits who need the survey operations. The performance of the survey mission was faster and more efficient. The survey information increased in quality and quantity. The new equipment guarantees flexibility and opportunity to the Field Artillery Battalion and fire is effective from the first shot. As regards the survey structure of a Field Artillery Battalion, there wasa diminution of the effectiveness, because of the smaller demands of equipment operators. Overall, the survey mission in the exercises is satisfactory but with reduced capacity and advantages that could be improved. It is, especially, based on this factor that we present a proposal with the new structure for the survey "cell" of the Portuguese Army, the Survey Section.

Los estilos APA, Harvard, Vancouver, ISO, etc.

11

Mishra, Chinmay. "On-Site Regeneration of Granular Activated Carbon : A literature study, comparison and assessment of different regeneration methods to find potential on-site regeneration method in Sweden". Thesis, KTH, Hållbar utveckling, miljövetenskap och teknik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-291272.

Texto completo

Resumen

In this thesis project, different existing granular activated carbon regeneration methods/technologies are assessed based on existing literature. The project aims to identify and analyse the method with the highest on-site regeneration potential by using the Himmerfjärdsverket wastewater treatment plant as a reference and performing a cost estimation analysis. Information is gathered about different methods from the literature study and then sorted into the following parts: working principle, technology readiness and cost, advantages and disadvantages, and references (case studies). The methods are then assessed and compared by a scoring and weightage system, where the factors which are regeneration efficiency, ease of implementation, sustainability, cost, and reliability are weighted and then scored for each method. Furthermore, the highest scoring method is then compared to the proposed regeneration method at Himmerfjärdsverket. The results from my comparison and assessment show that chemical regeneration is the highest scored method, followed by microwave and wet-oxidation regeneration methods. On applying chemical regeneration at Himmerfjärdsverket, it is found out that it may indeed be cheaper and more sustainable than the proposed off-site regeneration method. However, thermal and biological regeneration are better alternatives at Himmerfjärdsverket than microwave and wet- oxidation. From the above results, chemical regeneration has the highest potential for on-site regeneration of granular activated carbon in Sweden.
Läkemedel i vatten är ett stort hot mot miljö och hälsa. Kommunalt avloppsvatten består av avloppsvatten från hushåll, privata och offentliga institutioner och dagvattenavrinning. En viktig läkemedelskälla i avloppsvatten är ett läkemedel som kommer in via urin och / eller avföring. Olika tekniker finns för avlägsnande av farmaceutiska rester och andra mikroföroreningar från avloppsvatten. En sådan teknik är adsorptionen av dessa rester med hjälp av Granulärt Aktivtkor (GAC). Aktivtkor (AC) är ett kolhaltigt material med liten pordiameter, stora porvolymer och hög specifik yta rea vid bearbetning. Det anses vara det bästa adsorptionsmedlet för att adsorbera organiska, oorganiska och giftiga metalljoner som finns i avloppsvattnet. Det finns två typer av aktivtkol som används för att avlägsna farmaceutiska rester: Granulärt aktivtkol och pulveriserat aktivt kol. Denna forskning syftar till att identifiera, jämföra och bedöma befintlig regenereringsteknik för att hitta den teknik som har störst potential och använda den på ett referensavloppsreningsverk. Det finns olika metoder för regenerering av använt aktivt kol (SAC). Dessa är termisk regenerering, kemisk regenerering, biologisk regenerering, elektrokemisk regenerering, mikrovågsregenerering och våt-oxidationsregenerering. Metoderna listas och förklaras med hjälp av deras arbetsprincip, beredskap, kostnad, fördelar, nackdelar och referenser till studier där de har använts. Flera kriterier / faktorer beaktas för bedömning och jämförelse av olika regenereringsmetoder. Faktorerna poängsätts sedan med hjälp av ett viktat poängsystem. Var och en av de ovannämnda faktorerna görs mellan 0–5 och tilldelas en vikt mellan 1–3. En högre poäng betyder bättre prestanda i den givna faktorn. Medan en högre vikt betyder betydelsen av faktorn. Från bedömningen visar sig kemisk regenerering vara den mest lämpliga metoden för regenerering av GAC på plats. Den minst lämpliga metoden är biologisk regenerering med en total poäng på 39. De två bästa regenereringsmetoderna på plats är kemisk och mikrovågsregenerering. I procent har kemisk regenerering och mikrovågsregenerering en rating på 93,3% och 90%. För att validera resultatet av bedömningen används Himmerfjärdsverket som referensavloppsverk. Himmerfjärdsverket bygger om och expanderar till en högteknologisk anläggning. Den nya anläggningen kommer att bestå av modern reningsteknik och hög reningskapacitet. Den planerade nya anläggningen förväntas vara klar 2025, medan byggandet påbörjades i januari 2020. I en studie genomförd av Syvab i samarbete med Ramboll, IVL och SU anges att det skulle behövas kolförbrukning på 15–20 g / m3 vatten. Den totala kostnaden per behandlat avloppsvatten skulle sannolikt öka med 20–30% till 2027 om läkemedelsreningen genomförs på Himmerfjärdsverket med hjälp av GAC och av regenereringsmetoden utanför anläggningen. Himmerfjärdsverket kommer att konsumera 3,92 ton kol dagligen eller 27,56 ton varje vecka. Detta kommer att kosta 28,7 miljoner SEK / år för 20 000 EBV (i värsta fall) och 11,5 miljoner SEK / år för 50 000 EBV. Medan kostnaden för kemisk regenerering av GAC med högsta regenereringseffektivitet uppskattas till 27,4 miljoner SEK / år för användning av flytande NaOH-lösning och 17,7 miljoner SEK / år för användning av fast NaOH för 20 000 EBV. För mängden 573 t / år kol kommer NaOH-förbrukningen att vara 2083,5 t / år, vilket kommer att kosta 7,1 och 10,9 miljoner SEK / år för 50 000 EBV. Eftersom kostnad är en av de viktigaste faktorerna som motverkar tillämpningen av metoder som är lika tillförlitliga som termisk regenerering. Om termisk regenerering implementeras på Himmerfjärdsverket kan installationen användas för att regenerera GAC från andra reningsverk från Stockholm. 2 GAC-bio filter i serieskapare bättre förutsättningar för biologisk regenerering av GAC samt ger låga föroreningskoncentrationer och höga syrekoncentrationer. För att lägga till det producerar Himmerfjärdsverket biogas som kan användas för att uppnå höga temperaturer som krävs enligt denna metod eller generera den erforderliga elen eller båda. I alla tre fall kommer kostnaden att minskas ytterligare. Avslutningsvis har kemisk regenerering den högsta regenereringspotentialen på plats bland alla andra studerade metoder. Medan termisk regenerering är nära den andra på grund av kolförlusten. En pilotstudie krävs för att validera de regenereringseffektivitet som nämns i litteraturen och bearbetningsförhållandena och typerna av adsorbera vid Himmerfjärdsverket behöver utvärderas liksom behandlingsförhållandena.

Los estilos APA, Harvard, Vancouver, ISO, etc.

12

Lalaouna, David. "Role d' ARN non codants régulateurs dans l' adaptation de Pseudomonas brassicacearum à la rhizosphère et aux fluctuations de l' environnement". Thesis, Aix-Marseille, 2012. http://www.theses.fr/2012AIXM4006.

Texto completo

Resumen

Pseudomonas brassicacearum a la particularité de générer une diversité intraclonale aussi bien in vitro qu'en conditions naturelles dans la rhizosphère de plantes. Ce phénomène de variation phénotypique commun chez les bactéries est un processus d'adaptation aux environnements changeants. Des données de transcriptomique issues de puces à ADN, contenant aussi bien des séquences codantes que non codantes, nous ont permis d'identifier les gènes dont l'expression est altérée et surtout de relier ce phénomène à l'expression d'ARN non codants régulateurs (ARNnc) de type Rsm qui sont sous le contrôle du système à deux composants GacS/GacA. Nous avons montré que des mutations ponctuelles dans les gènes gacS ou gacA sont à l'origine de cette variation phénotypique et que l'expression de l'un des trois gènes rsmX, rsmY ou rsmZ permet de restaurer le phénotype de la souche sauvage. L'importance de ces ARNnc dans la survie de la bactérie aux fluctuations de son environnement est dénotée par la duplication de rsmX en un gène que nous avons nommé rsmX-2, dont la fonction a été validée. Nos données suggèrent une activation exclusive des gènes rsmX-1 et rsmX-2 par GacA et l'intervention de régulateurs additionnels dans le cas de rsmY et rsmZ. Au vu de la redondance fonctionnelle de ces quatre ARNnc, nous avons investigué leur niveau d'expression et leur stabilité dans différentes conditions de culture et montré des différences pour les quatre ARNnc. En réponse à une carence en nutriments, l'expression des ARNnc Rsm est fortement activée et atteint son maximum quand le ppGpp est détecté dans le milieu, suggérant un lien entre le système Gac/Rsm et la réponse « stringente »
The plant-beneficial bacterium Pseudomonas brassicacearum forms phenotypic variants in vitro as well as in planta during root colonisation under natural conditions. Transcriptome analysis of typical phenotypic variants using microarrays containing coding as well as non-coding DNA fragments showed differential expression of several genes relevant to secondary metabolism and of the small non-coding RNA (ncRNA) genes rsmX, rsmY and rsmZ, which was characterized by down-regulation. Naturally occurring mutations in the GacS/GacA two-component system accounted for phenotypic switching. The importance of these ncRNAs in the survival of the bacteria to changing environments is denoted by the duplication of rsmX gene, which we called rsmX-2 and whose function has been validated. Our data suggest an exclusive activation of rsmX-1 and rsmX-2 genes by GacA and the involvement of additional regulators in the case of rsmY and rsmZ. Given the functional redundancy of these ncRNAs, we investigated their expression level and stability in different culture conditions and showed differences for the four ncRNAs. In response to nutrient depletion, the four ncRNAs expression is strongly activated and reaches its maximum when the ppGpp is detected in bacterial cells, suggesting a link between the Gac/Rsm system and the "stringent" response. Determining the level of each Rsm ncRNA, which is defined by a balance between synthesis and degradation of each transcript, shows the maintenance of a very important pool of RsmZ compared to other ncRNAs

Los estilos APA, Harvard, Vancouver, ISO, etc.

13

Ahart, Megan Leanne. "Sorption and desorption of the industrial chemical MCHM into polymer pipes, liners and activated carbon". Thesis, Virginia Tech, 2015. http://hdl.handle.net/10919/73425.

Texto completo

Resumen

Polyethylene pipes and epoxy or polyurethane linings are increasingly used in drinking water infrastructure. As a recent introduction to the water industry, there are still many unknowns about how polymers will behave in the distribution system specifically relating to sorption and desorption of chemical contaminants. This study is in response to a spill of 4-methylcyclohexane methanol (MCHM) that occurred in January 2014 contaminating the drinking water of nine counties in West Virginia. This study investigated sorption and desorption of the odorous chemical MCHM into polymer drinking water infrastructure and granular activated carbon (GAC). Experiments for sorption of non-polar toluene and polar 1-butanol were conducted as a comparison for MCHM sorption. Additionally, a brief odor analysis was done on the ability of activated carbon to remove odor from contaminated water and on leaching of MCHM from pipe material into clean water. The results show that MCHM diffusion and solubility in polyethylene pipe materials is low. Solubility in polyethylene ranged from 0.003-0.008 g/cm3 and was more similar to the polar contaminant n-butanol than the non-polar contaminant toluene. Desorption experiments indicated that MCHM sorbed to polyethylene diffused back into water at levels that produced odor. MCHM diffused very quickly into epoxy; its solubility was similar to polyethylene pipe. MCHM caused the polyurethane lining to swell and deform. Granular activated carbon effectively sorbed MCHM to below its odor threshold. The sorption properties of MCHM indicate the potential for contamination of infrastructure and the desorption indicates subsequent recontamination of drinking water.
Master of Science

Los estilos APA, Harvard, Vancouver, ISO, etc.

14

Lamoureux, Tara. "Ozone and GAC Treatment of a Central Florida Groundwater for Sulfide and Disinfectant By-Product Control". Master's thesis, University of Central Florida, 2013. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/5656.

Texto completo

Resumen

This study evaluated the combination of ozone and granular activated carbon (GAC) treatment for the removal of sulfide and disinfection byproduct (DBP) precursors in drinking water at the pilot-scale. The research conducted was performed at the Auxiliary (Aux) and Main Water Treatment Plants (WTPs) in Sanford, Florida. Both WTPs rely upon groundwater sources that contain total sulfide ranging from 0.02 to 2.35 mg/L and total organic carbon (TOC) ranging from 0.61 to 2.20 mg/L. The Aux WTP’s raw water contains, on average, 88% more sulfide and 24% more TOC than the Main WTP. Haloacetic acids (HAA5) and total trihalomethanes (TTHMs) comprise the regulated forms of DBPs. HAA5 are consistently below the maximum contaminant level (MCL) of 60 μg/L, while TTHM ranges from 70 to 110 μg/L, at times exceeding the MCL of 80 μg/L in the distribution system. Ozone alone removed total sulfide and reduced UV-254 by about 60% at the Aux Plant and 35% at the Main Plant. Producing an ozone residual of 0.50 mg/L prevented the formation of bromate while removing approximately 35 to 60% concentration of DBP precursors as measured by UV-254. Operating the GAC unit at an empty bed contact time (EBCT) of 10 minutes for the Aux Plant and 5.5 minutes for the Main Plant resulted in 75% and 53% of UV-254 reduction, respectively. The average 120 hour TTHM formation potential for the Aux and Main Plants were 66 μg/L and 52 μg/L, respectively, after treatment by ozone and GAC. GAC exhaustion was deemed to have occurred after seven weeks for the Aux Plant and eleven weeks for the Main Plant. The GAC columns operated in three phases: an adsorption phase, a transitional phase, and a biologically activated carbon (BAC) phase. The GAC adsorption phase was found to produce the lowest TTHMs; however, TTHMs remained less than 80 μg/L during the BAC stage at each plant. BAC exhaustion did not occur during the course of this study. Ozone-GAC reduced chlorine demand by 73% for the Aux Plant and 10% for the Main Plant.
M.S.Env.E.
Masters
Civil, Environmental and Construction Engineering
Engineering and Computer Science
Environmental Engineering

Los estilos APA, Harvard, Vancouver, ISO, etc.

15

Righetti, Karima Maria. "Study of Rsm/Gac post-transcriptional regulation by quorum sensing, extracellular and intracellular signals in Pseugomonas aeruginosa". Thesis, University of Nottingham, 2011. http://eprints.nottingham.ac.uk/13853/.

Texto completo

Resumen

Bacteria have evolved ways to sense and respond to changes in their population density through quorum sensing (QS) systems, and to adapt to changes in the extracellular environment through two component systems (TCS). In Pseudomonas aeruginosa, QS and the GacS/GacA TCS are global regulatory systems that modulate the expression of virulence genes at the transcriptional and post-transcriptional level, respectively. Although in P. aeruginosa the QS network has been extensively characterized, the way the Gac/Rsm global regulatory system is regulated is still unclear. The study of QS and Gac/Rsm networks is crucial for the development of new drugs able to interfere with these regulatory systems. This thesis is dedicated to the study of the Gac/Rsm global regulatory system and its interaction with the QS network. An introduction to these systems is presented in Chapter 1. The materials and methods used in this study are described in Chapter 2. In Chapter 3 the methods to detect and identify the extracellular signals modulating Gac/Rsm system are investigated. This analysis led to the identification of the Pseudomonas Quinolone Signal (PQS) molecule, which is responsible for the activation of the gene coding for the small RNA RsmZ. RsmZ (in synergy with RsmY) antagonises by titration the effects of the global post-transcriptional regulator RsmA, a small RNA-binding protein which targets specific mRNAs. Since the discovery of QS, there have been many studies showing the importance of this type of regulatory mechanism in the global transcriptional control of gene expression. However, there has been no clear evidence to attribute to QS a key role in post-transcriptional regulation of terminal gene targets. In Chapter 4, the importance of PQS in the control of lecA is demonstrated. lecA encodes for the PA-I galactophilic lectin protein whose translation rates is modulated by the activity of the regulatory small RNA rsmZ in concert with RsmA. These results demonstrate that QS not only controls terminal target gene expression at the transcriptional level, but also at the translational level. Using a genetic bank, a transposon mutagenesis and a promoter pull-down approach, new regulators were identified together with regulatory networks involved in the modulation of the global Gac/Rsm system. These results are described in Chapter 5. Chapter 6 is focused on the effect of a library of compounds available in our laboratory, for their QS-inhibiting potential. The conclusions and future directions are presented in Chapter 7.

Los estilos APA, Harvard, Vancouver, ISO, etc.

16

WILSON, GREGORY. "ANAEROBIC/AEROBIC BIODEGRADATION OF PENTACHLOROPHENOL USING GAC FLUIDIZED BED BIOREACTORS: OPTIMIZATION OF THE EMPTY BED CONTACT TIME". University of Cincinnati / OhioLINK, 2002. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1018531262.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

17

Kelley, Thomas M. "Using Rapid Small Scale Column Testing to Evaluate Granular Activated Carbon Adsorption of Cyanotoxins from Drinking Water". University of Cincinnati / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=ucin150514901618082.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

18

Bales, Dustin William. "Optimization of an Advanced Water Treatment Plant: Bromate Control and Biofiltration Improvement". Scholar Commons, 2012. http://scholarcommons.usf.edu/etd/4286.

Texto completo

Resumen

The David L. Tippin Water Treatment Facility (DLTWTF) serving the city of Tampa, Florida is an advanced drinking water treatment facility consisting of coagulation/flocculation, ozonation, granular activated carbon biofiltration, and disinfection by chloramine. New regulations and the recent economic crisis pushed the facility to investigate methods to decrease costs and meet regulatory requirements easier. The two major issues identified as priorities for investigation were the optimization of the biofiltration system and the use of a novel process to reduce the formation of bromate during ozonation. Optimization of the biofiltration system is needed to remove more of the assorted particles that cause biofilms, nitrification in the distribution system, and high chloramine demand. Previous work improved the removal of particles that cause biofilms and nitrification, but was not able address the removal of particles that cause high chloramine demand to a satisfactory degree. Possible factors affecting this high chloramine decay were identified and evaluated at the pilot scale, including filter depth, chloramination of filter backwash water, media material, and nutrient addition. Non-chlorinated backwash water reduced chloramine demand by approximately 30% for GAC filters, and by approximately 50% for anthracite. Generally, anthracite performed slightly worse than GAC. Nutrient addition showed no effect. Filter depth improved chloramine decay, but not significantly enough to warrant the increased material required Bromate control is necessary to prevent the formation of bromate, a regulated carcinogen. Traditional bromate control methods use pH depression. While effective, at the DLTWTF, this forces the increased use of more expensive caustic soda over lime for raising the pH of process water. A novel process known as the chlorine-ammonia process was investigated at the bench scale to identify the ideal ratio of chlorine and ammonia to decrease the formation of bromate to ensure regulatory compliance and allow greater use of lime to decrease costs. The best ratio in this study is 0.45 mg/L NH3 to 0.75 mg/L Cl2 which produced 1.09 ppb bromate at a CT of 6.8 min*mg/L, representing a 84% improvement over the control.

Los estilos APA, Harvard, Vancouver, ISO, etc.

19

Mai, Huynh Cang. "Contribution au developpement d'un procédé visant à la valorisation d'extraits du fruit de gac (Momordica Cochinchinensis Spreng.) au Vietnam". Doctoral thesis, Universite Libre de Bruxelles, 2014. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209349.

Texto completo

Resumen

Le fruit de gac (Momordica cochinchinensis Spreng.) est un fruit traditionnel au Vietnam, lequel est extrêmement bénéfique pour la santé. L’arille de gac est une excellente source de caroténoïdes naturels, particulièrement le lycopène et le β-carotène. Ces composés antioxydants sont capables de neutraliser les radicaux libres et offrent des applications multiples, allant des effets généraux sur la santé à la prévention de certaines maladies chroniques. Ce travail a contribué au développement d’un procédé visant à la valorisation d’extraits du fruit de gac au Vietnam. Ce travail contient quatre parties principales: effet du semi-séchage sur les propriétés d’antioxydantes du fruit de gac; extraction de l’huile du fruit de gac assistée par enzymes; concentration des caroténoïdes de l’huile de gac par la filtration tangentielle; purification et cristallisation des caroténoïdes.

Dans la première partie, une étude du semi-séchage de l´arille de gac à différentes températures (40°C, 50°C, 60°C, 70°C et 80°C) et à trois modes de séchage (séchage à l’air, séchage sous vide et lyophilisation) a été effectuée pour déterminer l’effet de la mode, de la température et de l’humidité finale de séchage sur la couleur, la teneur en caroténoïdes totaux (TCC) et l’activité d’antioxydante totale (TAA) de l’arille de gac. Les résultats montrent que la lyophilisation permet une meilleure conservation permettant une valorisation ultérieure de la couleur, la TCC et la TAA de l’arille de gac. Le séchage sous vide donne les meilleurs résultats que le séchage à l’air. Une température entre 50°C et 60°C est optimale pour conserver la couleur, la TCC et la TAA de l’arille. Ces propriétés sont mieux conservées à l’issue d’un séchage permettant une humidité finale du produit de 15 à 18% (base sèche (db)) (semi-séchage) par rapport à 6% db. Le produit semi-séché peut être conservé pendant quelques mois.

Dans la deuxième partie, une étude d’optimisation d’extraction de l’huile de l’arille de gac assisté par des enzymes a été menée en utilisant la méthodologie de la surface de réponse. Un plan expérimental du type «design composite central» avec quatre variables indépendantes - la concentration en enzymes, le temps, la température et la vitesse d'agitation - a été réalisé. Les résultats montrent que ces quatre variables ont un effet significatif sur le rendement d’extraction de l’huile. Il n'y a pas d'interaction significative entre ces variables. Dans les conditions optimales obtenues (14,6% d’enzyme, 127 minutes, 58°C et 162 rpm), le rendement maximal de l’huile et la TCC obtenus sont de 79,5% et 5,3 mg/g de matière sèche, respectivement. Il existe une forte corrélation entre le rendement de l’huile obtenue et la TCC. Les propriétés physico-chimiques de l'huile extraite ont été déterminées. Enfin, les résultats du test Schaal montrent que le temps de conservation de l'huile extraite est comparable à d’autres huiles alimentaires, présentant le même type de profil en acides gras.

Dans la troisième partie, les caroténoïdes de l'huile ont étés concentrés à l'aide d'une filtration tangentielle, en utilisant une membrane céramique, selon deux modes de fonctionnement (recyclage total et batch). Dans les expériences en mode recyclage total, l'effet de la taille des pores de la membrane, la température et la pression transmembranaire sur le flux de perméat et le coefficient de rétention a été exploité. Les résultats montrent que ces facteurs ont un effet sur flux de perméat et le coefficient de rétention de la TCC, des phospholipides et des acides gras libres. La résistance intrinsèque de la membrane, la résistance de polarisation et la résistance liée au colmatage ont été estimées. Les conditions optimales déterminées sont 5 nm, 2 bars et 40°C, pour la taille des pores, la pression transmembranaire et la température, respectivement. En mode batch, le rétentat a été caractérisé en mesurant l'acidité, les phospholipides, la TCC, la TAA, des solides solubles totaux, la teneur en matières solides, la couleur et la viscosité de la solution. La TCC dans le rétentat est de 65,28 mg/ml (8,65 fois supérieure à celle dans l'huile d'alimentation). Les analyses de la TAA montrent que la contribution antioxydante principale de l'huile gac est lipophile. Après la filtration, la TAA lipophile du rétentat est 6,8 fois supérieur à celle de l’huile d’alimentation. L’analyse de la résistance indique que la résistance intrinsèque de la membrane représente 24% de la résistance totale. La majeure partie de la résistance est la résistance de polarisation (55%) tandis que la résistance de colmatage contribue pour 30%.

Dans la quatrième partie, les caroténoïdes provenant de l’huile du fruit de gac ont étés purifiés et cristallisés par une saponification combinée à l'utilisation de propylène glycol (un solvant moins toxique que les solvants organiques généralement utilisés). Ce processus est compatible à une consommation humaine, aux applications cosmétiques et plus respectueux de l'environnement que les procédés existants. Les résultats indiquent que l'utilisation de Tween 80 (0,05 ml/g d’huile) comme émulsifiant peut aider à augmenter la récupération des cristaux de caroténoïdes. La combinaison de 0,4 ml/g d'hydroxyde de potassium et 0,8 ml/g de propylène glycol donne un meilleur rendement de caroténoïdes. Une étude d’optimisation du processus de purification a été réalisée en utilisant la méthodologie de surface de réponse. Un plan expérimental du type «design composite central» avec trois variables indépendantes- la vitesse d'agitation, la température et le temps de réaction - a été effectué. Les résultats montrent que ces trois variables ont un effet significatif sur la récupération des caroténoïdes par cristallisation. Les interactions entre la vitesse d'agitation et la température ainsi qu’entre la température et le temps de réaction sont significatives. Dans les conditions optimales (1094 rpm; 46°C et 228 min), le rendement de caroténoïdes estimé est de 93,5%. Les cristaux de caroténoïdes contiennent 57,34% de lycopène et 36,67% de β-carotène. Ces résultats montrent que environ 85% et 78% du lycopène et du β-carotène, respectivement, ont étés récupérés.

Dans l’ensemble, cette thèse a contribué à la valorisation du fruit de gac au Vietnam, par une procédure de fabrication qui est économique et utilisant moins de produits chimiques. La recherche a permis de trouver les conditions optimales pour chaque étape de fabrication. Un nouvel axe de recherche pour valoriser le fruit de gac a été ouvert; il porte sur l’étude de l’application tant de l’huile de gac concentrée et riche en caroténoïdes naturels que des cristaux de caroténoïdes dans l’industrie alimentaire, pharmaceutique ou cosmétique.

Doctorat en Sciences de l'ingénieur
info:eu-repo/semantics/nonPublished

Los estilos APA, Harvard, Vancouver, ISO, etc.

20

Jacque, Nathalie. "Étude du métabolisme de la glutamine dans les leucémies aiguës myéloïdes". Thesis, Sorbonne Paris Cité, 2015. http://www.theses.fr/2015USPCB221/document.

Texto completo

Resumen

La survie des cellules cancéreuses dépend d’une activité énergétique et biosynthétique accrue et la glutamine participe à de nombreux processus nécessaires à cette adaptation métabolique. Dans les leucémies aiguës myéloïdes (LAM), la croissance et la prolifération sont favorisées par l’activation anormale de plusieurs voies de signalisation, et notamment par la voie mTORC1. Les acides aminés essentiels, et en particulier la leucine, sont indispensables à l’activation de mTORC1. La glutamine est captée par la cellule via le transporteur SLC1A5 et permet ensuite l’entrée de la leucine via le transporteur bidirectionnel SLC7A5. La concentration en glutamine est donc une étape limitante dans l’activation de mTORC1 par la leucine. Nous avons étudié les effets de la privation en glutamine dans les LAM à l’aide de différents outils (milieu sans glutamine, shARN inhibant l’expression du transporteur de la glutamine SLC1A5 et la drogue L-asparaginase, qui a une activité de glutaminase extracellulaire), et observé une inhibition de mTORC1 et de la synthèse protéique. L’inhibition du transporteur SLC1A5 inhibe la pousse tumorale dans un modèle de xénotransplantation. La L-asparaginase inhibe mTORC1 et induit une apoptose de façon proportionnelle à son activité glutaminase et complètement indépendante de la concentration en asparagine. La privation en glutamine induit l’expression de la glutamine synthase et l’autophagie, et ces deux processus peuvent être des mécanismes de résistance intrinsèques ou acquis dans certaines lignées leucémiques. L’apoptose induite par la privation en glutamine n’est cependant pas liée à l’inhibition de mTORC1, puisqu’elle n’est pas diminuée par l’utilisation d’un mutant de mTOR non inhibé par la privation en glutamine. Nous nous sommes donc intéressés à une autre voie dépendante de la glutamine dans de nombreux cancers, la phosphorylation oxydative. L’étape initiale du catabolisme intracellulaire de la glutamine est la conversion de la glutamine en glutamate par des enzymes appelées glutaminases. Différentes isoformes des glutaminases existent qui sont codées chez l’homme par les gènes GLS1 et GLS2. Le glutamate est ensuite transformé en α-cétoglutarate, intermédiaire du cycle TCA. Dans les lignées de LAM, la privation en glutamine inhibe la phosphorylation oxydative mitochondriale. Nous avons observé que la protéine glutaminase C (GAC), une des isoformes de GLS1, est constamment exprimée dans les LAM mais aussi dans les progéniteurs hématopoïétiques CD34+ normaux. L’inhibition d’expression de la GLS1 par des shARN inductibles ou bien par le composé CB-839 réduit la phosphorylation oxydative, conduisant à une inhibition de prolifération et à une induction d’apoptose des cellules leucémiques. L’invalidation génétique de la GLS1 inhibe la formation de tumeur et améliore la survie des souris dans un modèle de xénotransplantation. A l’inverse, le ciblage de la GLS1 n’a pas d’effets cytotoxiques ni cytostatiques sur les progéniteurs hématopoïétiques normaux. Ces effets anti-leucémiques sont inhibés par l’adjonction d’α-cétoglutarate, et ceux induit par le CB-839 sont abrogés lorsqu’est exprimé de façon ectopique un mutant GACK320A hyperactif, attestant du rôle essentiel du maintien d’un cycle TCA actif dans les cellules de LAM. Enfin, nous montrons que l’inhibition de la glutaminolyse active la voie d’apoptose mitochondriale intrinsèque et agit en synergie avec l’inhibition spécifique de BCL-2 par l’ABT-199. Ces résultats démontrent que le ciblage spécifique de la glutaminolyse est une autre façon d’exploiter l’addiction à la glutamine des cellules leucémiques de LAM et que le maintien d’un cycle TCA actif est essentiel à la survie de ces cellules
Cancer cells survival is dependent on high energetic and biosynthetic activity, and glutamine is involved in many metabolic processes necessary for this adaptation. In acute myeloid leukemia (AML), growth and proliferation are promoted by activation of several signaling pathways, including mTORC1. Essential amino acids, in particular leucine, are required for mTORC1 activation. Glutamine enters into the cell via the SLC1A5 transporter and then allows the input of leucine via the bidirectional SLC7A5 transporter. Therefore, the intracellular glutamine concentration is a limiting step in the activation of mTORC1 by leucine. We studied the effects of glutamine deprivation in AML using different tools (medium without glutamine, shRNA against the SLC1A5 glutamine transporter and the drug L-asparaginase, which has an extracellular glutaminase activity) and observed mTORC1 and protein synthesis inhibition. SLC1A5 transporter knockdown inhibits tumor growth in a xenotransplantation model. L-asparaginase inhibits mTORC1 and induces apoptosis in proportion to its glutaminase activity and independently of asparagine concentration. Glutamine privation induces the expression of glutamine synthase and autophagy, and these two processes are involved in the resistance to glutamine privation in some leukemic cell lines. However, apoptosis induced by glutamine privation is not related to the inhibition of mTORC1, since it is not modified in the presence of a constitutively active mutant of mTOR. We next focused on the oxidative phosphorylation, another glutamine dependent pathway in many cancers. The initial step of the intracellular catabolism of glutamine is the conversion of glutamine to glutamate by enzymes called glutaminases. Different glutaminases isoforms exist that are encoded by the GLS1 and GLS2 genes. Glutamate is then converted to α-ketoglutarate, an essential TCA cycle intermediate. In AML cell lines, we observed that glutamine privation inhibits mitochondrial oxidative phosphorylation. The protein glutaminase C (GAC), an isoform of GLS1, is constantly expressed in AML but also in normal CD34 + hematopoietic progenitors. The knockdown of GLS1 by inducible shRNA or by the CB-839 compound reduced oxidative phosphorylation, leading to proliferation inhibition and apoptosis induction in leukemia cells. Genetic invalidation of GLS1 inhibits tumor formation and improves survival of mice in a xenograft model. Conversely, the targeting of GLS1 has no cytotoxic or cytostatic effects on normal hematopoietic progenitors. These anti-leukemic effects are inhibited by the addition of α-ketoglutarate, and those induced by the CB-839 are suppressed in the presence of an ectopically expressed GACK320A hyperactive mutant, confirming the essential role of maintaining an active TCA cycle in AML cells. Finally, we showed that glutaminolysis inhibition induces the intrinsic mitochondrial pathway of apoptosis and acts synergistically with the specific inhibition of BCL-2 by ABT-199. These results demonstrate that specific targeting of glutaminolysis is another way to exploit glutamine addiction in AML and that an active TCA cycle in essential for AML cell survival

Los estilos APA, Harvard, Vancouver, ISO, etc.

21

Bäckström, Nilsson Wilma. "Carbon Filters for Drinking Water Treatment – How Flow Rate and Empty Bed Contact Time Influence the Performance". Thesis, KTH, Kemiteknik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-298356.

Texto completo

Resumen

Dricksvatten är en essentiell del av ett hållbart samhälle. Därför är det viktigt att säkerställa säkert dricksvatten genom fungerande vattenreningsverk. En viktig förorening att behandla är NOM, som i sig är ofarligt men som kan producera farliga föroreningar. En teknik som används för behandling av NOM är kolfiltrering. Hur ökad flödeshastighet och ökad kontakttid påverkade kolfiltrens effektivitet undersöktes vid dricksvattenreningsverket Norrvatten. De undersökta parametrarna var partiklar, ultraviolett absorbans vid 254 nm, turbiditet, konduktivitet, fluorescent löst organiskt material, totalt organiskt kol, kemisk syreförbrukning, odlingsbara mikroorganismer och lukt. Tre kolfilter studerades vid olika flödeshastigheter; 190, 220, 250 och 280 L/s under ett dygn var. Samtidigt hade två filter ökad kontakttid på 60 och 76 % under sex veckor, medan ett filter fortsatte med den vanliga flödeshastigheten på 190 L/s. Utgående vatten från filtren analyserades för att se om dessa ändringar hade någon effekt på vattenreningen. Denna preliminära studie fann ingen signifikant effekt på kolfiltreringens rening på grund av ökad flödeshastighet eller uppehållstid. Detta kan vara en indikation på att kolfiltreringen kan hantera en framtida flödesökning och därmed vara en väsentlig del av en framtida expansionen av vattenreningsverket. De tecken som visade på att kolfiltren påverkades av ökningen av flödeshastigheter kunde förklaras av fluktuationer i inkommande vatten och skillnader mellan de olika filtren. I framtiden bör effekten av inkommande vatten studeras i detalj. En mer ingående analys av både inkommande och utgående vatten till kolfiltren bör utföras, där provtagning sker oftare för att bättre förstå fluktuationerna i inkommande föroreningskoncentrationer. Dessutom bör testerna upprepas för att se hur reningen skiljer sig från dag till dag. Hur kolfiltren hanterar ökade flödeshastigheter över längre tidsperioder bör också undersökas vidare.
Drinking water is an essential part of a sustainable society. In the future, the demand for drinking water will increase and contaminants in the water sources are also predicted to increase. Therefore, it is essential to ensure safe drinking water through functioning drinking water treatment plants (DWTPs). One important contaminant to treat is natural organic matter (NOM), which is harmless in itself but can produce harmful products. One technique to use for treating NOM is carbon filters (CFs). The effect of increased flow rate and increased empty bed contact time (EBCT) on the CF efficiency was investigated at a DWTP. The investigated parameters were particles, ultraviolet absorbance at 254 nm, turbidity, conductivity, cultivable microorganisms, fluorescent dissolved organic matter, total organic carbon, chemical oxygen demand, and odour. Three CFs were studied at different flow rates; 190, 220, 250, and 280 L/s for 24 hours each. Additionally, two filters had increased EBCT of 60 and 76 %, while one filter continued with the regular flow rate of 190 L/s for six weeks. Outgoing water from the filters was analysed to see if the change had any effect on the DWTP. This preliminary study did not find any significant effect on the CF treatment caused by increased flow rate or EBCT. This could be an indication that the CFs can handle a future increase in flow rate and thus be an essential part of a future expansion of the DWTP. The indications of CFs being affected by the increase in flow rates for some of the parameters could be explained by fluctuations in incoming water or differences between the separate filters. In the future, a more thorough analysis of both incoming and outgoing water to the CFs should be done, where sampling occurs more frequently to better understand the fluctuations in incoming contaminant concentrations. The measurements should also be repeated to see how the treatment differs from day to day. How the CFs handle increased flow rates over longer time periods should also be investigated further.

Los estilos APA, Harvard, Vancouver, ISO, etc.

22

Phan, Thi Hanh. "Utilisation des caroténoïdes naturels de Momordica cochinchinensis (gac) comme composés santé : extraction et bioactivité en fonction de l'origine et du procédé". Thesis, Dijon, 2014. http://www.theses.fr/2014DIJOS087/document.

Texto completo

Resumen

L’arille de Momordica cochinchinensis (gac), un fruit de la famille des Cucurbitacées, est la source végétale la plus riche en lycopène et β-carotène. Ces deux composés ont, respectivement, un rôle de puissant antioxydant et de provitamine A, intéressant les compléments santé. Tout d'abord, un procédé d’extraction fractionnée douce a été développé pour extraire ces caroténoïdes naturels en gardant leur qualité originale. Puis, le lycopène et le β-carotène extraits ont été caractérisés et analysés. Au moins 95 % des extraits sont composés de l’isomère all-trans. Ils ne sont pas dégradés pendant le traitement thermique représentant les procédés de formulation. Leur stéréo-mutation thermique a été évaluée. Le lycopène est plus antioxydant et donc plus rapidement isomérisé que le β-carotène à haute température. L’isomérisation augmente leur activité antioxydante, qui a été évalué par test chimique TEAC et sur l’hémolyse des cellules sanguines (KRL) in vitro. Les deux caroténoïdes de l’arille de gac sont beaucoup plus antioxydants que le Trolox contre l’hémolyse. En comparant avec d’autres sources de β-carotène, les caroténoïdes extraits de gac dans ces conditions douces restent antioxydants même à des concentrations plus élevées contrairement à ceux extraits dans des conditions classiques qui deviennent prooxydants. Ces résultats permettent de discuter la bioactivité des caroténoïdes d'après leur qualité et de leur origine, c’est à dire leur source et leur procédé d’extraction. D’un point de vue applicatif, outre le procédé de fractionnement qui est industrialisable, le traitement thermique appliqué permet de contrôler la fonctionnalité des produits riches en caroténoïdes
The aril of Momordica cochinchinensis (gac), plant from the Cucurbitaceae family, is the richest source of lycopene and β-carotene, which are a strong antioxidant and a pro-vitamin A, respectively, interesting for health-complements. First, a process of soft extraction-fractionation was developed for extracting effectively the natural carotenoids from gac without loss of their original quality. Then, the lycopene and β-carotene extracted from gac were analyzed and characterized. At least 95% of the extracts were composed of the all-trans isomer. They were not degraded during the heat-treatment mimicking formulation processing. Their thermal stereo-mutation was evaluated. Lycopene is more antioxidant, it is thus isomerized more rapidly than β-carotene at high temperature. The isomerization of carotenoids increases their antioxidant activity that was evaluated by the chemical test TEAC and through the hemolysis of red blood cells (KRL) in vitro. The lycopene and β-carotene from gac are notably more antioxidant than Trolox. By comparing with other sources of β-carotene, carotenoids extracted from gac in these soft conditions keep their antioxidant properties, even at high concentration, contrasting with extracts obtained in classical conditions that become prooxidant. From these results, the bioactivity of carotenoids is discussed from their quality and their origin that is their source and extraction process. For application, in addition to the fractionation process which is easily transferable to the industry scale, the heat-treatment used in this study is interesting for controlling products rich in functional carotenoids

Los estilos APA, Harvard, Vancouver, ISO, etc.

23

Silva, Mateus Veronese Corrêa da. "UM SÉCULO DE HISTÓRIA: INVENTÁRIO DO PATRIMÔNIO CULTURAL EDIFICADO DO 29º GAC AP GRUPO HUMAITÁ NO MUNICÍPIO DE CRUZ ALTA/RS". Universidade Federal de Santa Maria, 2015. http://repositorio.ufsm.br/handle/1/11063.

Texto completo

Resumen

The architectural heritage of a place is not just the architectural elements expressed in its construction, but through memory, the historical burden and the daily experiences of the people involved in its existence. Thus, the government and the community in which this heritage is inserted, need to recognize its preservation as a means of safeguarding its history. At the same time, this expression is one of the most significant events for the understanding of urban history, so it is essential to carry out analyzes that reveal the cultural and constructive aspects arranged in its walls. Thus, this paper proposed to inventory the architectural ensemble of an example of the military heritage present in the city, built in 1909, Vigésimo Novo Grupo de Artilharia de Campanha Auto Propulsada, known by the nickname Grupo Humaitá. The research aims to highlight the historical, cultural and architectural aspects of the institution, emphasizing the analysis of the implementation and on the frontage of buildings, as a contribution to the pursuit of preservationist awareness. This information was cataloged by executors records as a way to contribute to the development of the inventory of military and civilian buildings of cultural interest in Cruz Alta and in Rio Grande do Sul. Through this work, it was intended to go along to enlarge the knowledge and dissemination of this property before the cruzaltense community, rescuing the memory, and providing subsidies to contribute to public policies and action plans in the areas of preservation of this heritage in the city as a way of disseminating the research, it was supposed to prepare a visual guide of the architectural repertoire of the buildings as a way to publicize the data and contribute to actions in favor of heritage education.
O patrimônio arquitetônico de um local não se resume apenas aos elementos arquitetônicos expressos na sua construção, mas através da memória, da carga histórica e da vivencia diária das pessoas envolvidas em sua existência. Desta forma, o poder público e a comunidade em que este patrimônio está inserido, necessita reconhecer a sua preservação, como meio de salvaguarda da sua história. Ao mesmo tempo, esta expressão representa uma das manifestações mais significativas para o entendimento da história urbana, por isso, é essencial a realização de análises que revelem os aspectos culturais e construtivos dispostos em suas paredes. Desta forma, o presente trabalho propôs inventariar através da ficha do IPHAN modificada, o conjunto arquitetônico de um exemplar do patrimônio militar presente no município, construído no ano de 1909, o Vigésimo Nono Grupo de Artilharia de Campanha Auto Propulsada, conhecido pela alcunha de Grupo Humaitá. A pesquisa busca dar destaque aos aspectos históricos, culturais e arquitetônicos da instituição, dando ênfase na análise da implantação e nas fachadas das edificações, como forma de contribuição para na busca da conscientização preservacionista. Estas informações foram catalogadas através de fichas inventariantes, além de análise do conjunto arquitetônico existente, como forma de contribuir para o desenvolvimento do inventário dos edifícios militares e civis de interesse cultural no município de Cruz Alta e no Rio Grande do Sul. Através deste trabalho, pretendeu-se colaborar no sentido de ampliar os conhecimentos e divulgação deste bem perante a comunidade cruzaltense, resgatando a memória, e fornecendo subsídios para contribuir para políticas públicas e planos de ações nas áreas de preservação do patrimônio presente no município. Como forma de divulgação da pesquisa, coube a elaboração de um guia visual do repertório arquitetônico das edificações, como forma de publicitar os dados obtidos e contribuir em ações em prol da educação patrimonial.

Los estilos APA, Harvard, Vancouver, ISO, etc.

24

Lindegren, Klara. "Evaluation of the Removal Efficiency of Per- and Polyfluoroalkyl Substances in Drinking Water using Nanofiltration Membranes, Active Carbon and Anion Exchange". Thesis, Uppsala universitet, Luft-, vatten och landskapslära, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-268448.

Texto completo

Resumen

Per- and polyfluoroalkyl substances (PFASs) is a group of man-made, highly persistent chemicals. Due to the specific surface-active attributes of these molecules, applications are numerous and feed an economically important industry. During the last decade, PFASs have been detected globally in the environment, living organisms and tap water. The combination of toxic properties and high bioaccumulative potential, together with the discovery that conventional water treatment methods do not remove PFAS, renders further research on purification methods highly needed. Three techniques of purifying water from PFASs were examined. Nanofiltration technology (NF) is a membrane filtration technique, which produces a purified product (the permeate) by generating an effluent of high contaminant concentration (the reject water). To decontaminate the reject water, adsorption by granular activated carbon (GAC) or anion exchange (AE) have been proposed. The efficiency of these three technologies was studied at Bäcklösa drinking water treatment plant (DWTP) in Uppsala. A nanofiltration pilot with two 270NF membranes (Dow Filmtech™), connected in series, was used. A high removal efficiency (>90%) was found for all PFASs. Furthermore, it was confirmed that the concentration in the permeate water was a function of the concentration in the incoming raw water; increased PFAS raw water concentration resulted in increased PFAS permeate concentration. Size-exclusion and electrostatic repulsion were deemed important mechanisms. For the comparison of GAC (Filtrasorb 400®) and AE (Purolite® A-600), a column experiment was set up. The perfluoroalkane (-alkyl) sulfonic acids (PFSAs) and perfluorooctanesulfonamide (FOSA) had similar removal efficiencies using both GAC and AE, and the efficiency increased with increasing chain length. AE was found to have a higher average removal efficiency of perfluoroalkyl carboxylic acid (PFCAs) (62-95%) than GAC (49-81%). In conclusion, longer chain length PFASs were removed more effectively than shorter-chained, and the PFSAs and FOSA showed higher removal efficiency compared to the PFCAs. Furthermore, linear isomers were removed more effectively than branched for GAC and AE. In contrast, the opposite was found for the NF membrane, where branched isomers were better retained.
Per- och polyfluorerade alkylsubstanser (PFAS) är en grupp syntetiska, ytterst persistenta kemikalier. På grund av deras ytaktiva egenskaper är de lämpliga för användning i många produkter och tillverkningsprocesser, och är således viktiga för en ekonomiskt betydande industri. Under det senaste årtiondet har PFAS påträffats i miljön, levande organismer och kranvatten världen över. Kombinationen av toxiska egenskaper, en hög bioackumuleringspotential och upptäckten att konventionella reningsmetoder inte avlägsnar substanserna från vatten, gör att vidare forskning av reningsmetoder för PFAS är mycket angelägen. Tre reningsteknikers förmåga att rena vatten från PFAS undersöktes. Nanofiltrering (NF) är en membranfiltreringsteknik som utöver den renade produkten, permeatet, även framställer en biprodukt av hög föroreningsgrad, rententatet. För att rena rententatet har adsorption till granulärt aktivt kol (GAC) eller jonbytarmassa (AE) föreslagits. Teknikerna utvärderades på Bäcklösa Vattenverk i Uppsala. Nanofiltreringen undersöktes i en pilotanläggning där två 270NF (Dow Filmtech™) membran var seriekopplade. En hög reningsgrad (>90%) konstaterades för alla typer av PFAS. Vidare visades PFAS-koncentrationen i permeatet vara en funktion av PFAS-koncentrationen i råvattnet; en ökad råvattenkoncentration gav en ökad permeatkoncentration. Storleksseparation och elektrostatisk repulsion befanns vara viktiga mekanismer som påverkade reningsgraden. För att undersöka de mekanismer som påverkar PFAS-adsorption jämfördes GAC (Filtrasorb 400®) och AE (Purolite® A-600) i ett kolonnexperiment. Reningsgraden för GAC och AE av perfluorerade sulfonsyror (PFSA) och perfluorooktan sulfonamider (FOSA) var lika hög och reningseffektiviteten ökade med ökande kolkedjelängd. AE återfanns ha en högre genomsnittlig reningsgrad av perfluorkarboxylsyror (PFCA) (62-95%) än GAC (49-81%). Sammanfattningsvis avlägsnades PFAS av längre kolkedjelängd mer effektivt än kortare kolkedjor, och PFAS med sulfonsyror och sulfonamider som funktionella grupper uppvisade en högre reningsgrad än karboxylsyrorna. Vidare renades linjära isomerer mer effektivt än grenade både genom GAC och AE. Däremot konstaterades det motsatta för NF-membranen, där grenade isomerer renades mer effektivt.
SafeDrink

Los estilos APA, Harvard, Vancouver, ISO, etc.

25

Montes-Rendón, Azucena. "Contribution à un modèle quasi-topologique pour la sémantique des langues". Paris 4, 2002. http://www.theses.fr/2002PA040131.

Texto completo

Resumen

La recherche présentée dans ce travail s'inscrit dans le cadre de l'analyse formelle de la sémantique des langues naturelles et porte particulièrement sur les prépositions et les préverbes sur, sous, par en français et sobre en espagnol. Nous proposons une méthode de descriptions pour construire des invariantes de signification de ces unités linguistiques. Plusieurs linguistes ont reconnu le besoin de la topologie comme outil d'analyse de l'espace et du temps encodés par les langues. Cependant la topologie classique définie pour exemple, en langue, la frontière ne réfère pas toujours à un point ou à une limite. Nous proposons une " théorie des lieux abstraits " où nous utilisons les opérateurs de l'algèbre de Kuratowski. Ces opérateurs d'intériorité, extériorité, frontière et fermeture sont définies avec de nouvelles propriétés telles que nous obtenons une quasi-topologie. Ce travail s'intègre dans le modèle de la Grammaire Applicative et Cognitive (GA &C)
This work presents a formal semantic analysis in natural languages, particularly in propositions and their associated prefixes, sur (on), sous (under), par (through) in French an sobre (on) in Spanish. We propose a theory of abstract places, as for a descriptive method for building an invariant meaning of these linguistics units. Many linguists have recognized the necessity of topological analysis for studying the spatial and temporal concepts encoded in languages. However, it seems to us that the elementary topology which has been defined for mathematical analysis, has not captured properly the linguistic problems in adequate way. For example, the notion of boundary which is expressed in languages shouldn't refer always to a point or a limit. We propose a theory of abstract places called " Abstract Loci Theory ". The theory make us of operators of Kuratowski's algebra for an elementary topology. The operators of interiority, exteriority, closure and boundary are defined with new properties such that we obtain a theory of "quasi-topology". The present study is based on the Grammar Applicative and Cognitive model (GA &C)

Los estilos APA, Harvard, Vancouver, ISO, etc.

26

Jonsson, Sofia. "The influence of soil and contaminant properties on the efficiency of physical and chemical soil remediation methods". Doctoral thesis, Umeå universitet, Kemi, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-21040.

Texto completo

Resumen

A vast number of sites that have been contaminated by industrial activities have been identified worldwide. Many such sites now pose serious risks to humans and the environment. Given the large number of contaminated sites there is a great need for efficient, cost-effective remediation methods. Extensive research has therefore been focused on the development of such methods. However, the remediation of old industrial sites is challenging, for several reasons. One major problem is that organic contaminants become increasingly strongly sequestered as they persist in the soil matrix for a long period of time. This process is often referred to as ‘aging’, and leads to decreasing availability of the contaminants, which also affects the remediation efficiency. In the work underlying this thesis, the influence of soil and contaminant properties on the efficiency of various physical and chemical soil remediation methods was investigated. The investigated contaminants were polycyclic aromatic hydrocarbons (PAHs), polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs). Briefly, the results show that as the size of soil particles decreases the contaminants become more strongly sorbed to the soil’s matrix, probably due to the accompanying increases in specific surface area. This affected the efficiency of the removal of organic pollutants by both a process based on solvent washing and processes based on chemical oxidation. The sorption strength is also affected by the hydrophobicity of the contaminants. However, for a number of the investigated PAHs their chemical reactivity was found to be of greater importance for the degradation efficiency. Further, the organic content of a soil is often regarded as the most important soil parameter for adsorption of hydrophobic compounds. In these studies the effect of this parameter was found to be particularly pronounced for the oxidation of low molecular weight PAHs, but larger PAHs were strongly adsorbed even at low levels of organic matter. However, for these PAHs the degradation efficiency was positively correlated to the amount of degraded organic matter, probably due to the organic matter being oxidized to smaller and less hydrophobic forms. The amount of organic matter in the soil had little effect on the removal efficiency obtained by the solvent-washing process. However, it had strong influence on the performance of a subsequent, granular activated carbon-based post-treatment of the washing liquid. In conclusion, the results in this thesis show that remediation of contaminated soils is a complex process, the efficiency of which will be affected by the soil matrix as well as the properties of the contaminants present at the site. However, by acquiring thorough knowledge of the parameters affecting the treatability of a soil it is possible to select appropriate remediation methods, and optimize them in terms of both remediation efficiency and costs for site- and contaminant-specific applications.

Los estilos APA, Harvard, Vancouver, ISO, etc.

27

Cochran, Jeff W. "Evaluation of pre and post treatment filtration performance of Kinetico Macrolite ceramic media compared to traditional sand/anthracite and GAC filters in drinking water treatment process". Birmingham, Ala. : University of Alabama at Birmingham, 2008. https://www.mhsl.uab.edu/dt/2008d/cochran.pdf.

Texto completo

Resumen

Thesis (Ph. D.)--University of Alabama at Birmingham, 2008.
Additional advisors: Robert A. Angus, Joe J. Gauthier, Jason T. Kirby, Robert W. Peters. Description based on contents viewed June 12, 2008; title from title screen. Includes bibliographical references (p. 85-87).

Los estilos APA, Harvard, Vancouver, ISO, etc.

28

Dlugolecka, Maja. "Pharmaceutical compounds : a new challenge for wastewater treatment plants /". Licentiate thesis, Stockholm : Mark- och vattenteknik, Kungliga Tekniska högskolan, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4348.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

29

Qiu, Yong. "STUDY ON TREATMENT TECHNOLOGIES FOR PERFLUOROCHEMICALS IN WASTEWATER". Doctoral thesis, 京都大学 (Kyoto University), 2007. http://hdl.handle.net/2433/44143.

Texto completo

Resumen

学位授与年月日: 2007-07-23 ; 学位の種類: 新制・課程博士 ; 学位記番号: 工博第2837号
Perfluorochemicals (PFCs) were produced by industries and consumed “safely” as surfactants, repellents, additives, fire-fighting foams, polymer emulsifiers and insecticides for almost fifty years. However they are now considered as persistent, bioaccumulated and toxic (PBT) chemicals, and ubiquitously distributed in waster, air, human body and biota. Although some efforts were contributed to reduce PFCs in environment, such as development of alternatives and recycling processes, huge amount of persisted PFCs have already been discharged in environment and accumulated in biota including humans. In some industrialized areas, such as Yodo river basin in Japan, water environment and human blood were polluted by some PFCs, and thus reduction and control of PFCs were urgently required for the purpose of environmental safety and human health in these areas. Unfortunately, some studies implied that current water and wastewater treatment processes seemed ineffective to remove PFCs in trace levels. Therefore, this study will try to develop some proper technologies to treat trace level of PFCs in wastewater. In order to achieve this main objective, several works have been accomplished as follows. 　Current available literature has been reviewed to obtain a solid background for this study. Basic information of PFCs was summarized in physiochemical properties, PBT properties, productions and applications, regulations and etc.. Analytical methods for PFCs, especially of LC-ESI-MS/MS, were reviewed including pretreatment processes in diverse matrices, which derived objectives of chapter III. Distributions and behavior of PFCs were briefly discussed in water environments, biota sphere and human bloods. Available control strategies were shown in detail about alternatives, industrial recycling processes, and newly developed treatment processes. Current wastewater treatment processes showed inefficient removal for some PFCs, deriving objectives of chapter IV on the PFC behavior in treatment process. Newly developed treatment technologies seemed able to decompose PFCs completely but unsuitable for application in WWTP. Therefore, granular activated carbon (GAC) adsorption and ultra violet (UV) photolysis were developed in chapter V and VI as removal and degradation processes respectively. 　Fifteen kinds of PFCs were included in this study, consisting of twelve kinds of perfluorocarboxylic acids (PFCAs) with 4~18 carbons and three kinds of perfluoroalkyl sulfonates (PFASs) with 4~8 carbons. An integral procedure was developed in chapter III to pretreat wastewater samples. LC-ESI-MS/MS was applied to quantify all PFCs in trace level. Pretreatment methods were optimized between C18 and WAX-SPE processes for aqueous samples, and between IPE, AD-WAX and ASE-WAX processes for particulate samples. Standard spiking experiments were regularly conducted for each wastewater sample to calculate recovery rate and control analytical quality. As the result, WAX-SPE showed better performance on samples with very high organics concentrations, and C18-SPE performed better for long-chained PFCs. ASE-WAX was proposed as the optimum method to pretreat particulate samples because of the simple and time saving operations. 9H-PFNA was used as internal standard to estimate matrix effect in wastewater. 　Behavior of PFCs in a municipal WWTP has been studied in chapter IV by periodical surveys for six times in half a year. All PFCs used in this study were detected in WWTP influent and effluent. According to their carbon chain lengths, all PFCs can be classified into “Medium”, “Long” and “Short” patterns to simplify behavior analysis. PFCs in same pattern showed similar properties and behavior in wastewater treatment facilities. Very high concentrations of PFCs existed in WWTP influent, indicating some point sources of industrial discharge in this area. “Medium” PFCs, such as PFOA(8), PFNA(9) and PFOS(8), were primary contaminants in the WWTP and poorly removed by overall process. Performances of individual facilities were estimated for removal of each PFC. Primary clarification and secondary clarification were helpful to remove all PFCs in both aqueous phase and particulate phase. “Medium” PFCs in aqueous phase were increased after activated sludge process, but other PFCs can be effectively removed. Ozone seemed ineffective to decompose PFCs because of the strong stability of PFC molecules. Sand filtration and biological activated carbon (BAC) filtration in this WWTP can not remove PFCs effectively too, which required further studies. Performances of combined processes were estimated by integrating individual facilities along the wastewater flow. Activated sludge process coupled with clarifiers showed satisfied removal of most PFCs in the investigated WWTP except “Medium” PFCs. 　Adsorption characteristics of PFCs onto GAC have been studied by batch experiments in chapter V. Freundlich equation and homogenous surface diffusion model (HSDM) were applied to interpret experimental data. Isothermal and kinetics experiments implied that PFC adsorption on GAC was directly related with their carbon chain lengths. By ascendant carbon chain length, adsorption capacity for specific PFC was increased, and diffusion coefficient (Ds) was decreased. Ds of GAC adsorption was also decreased gradually in smaller GAC diameters. Coexisted natural organic matters (NOMs) reduced adsorption capacities by mechanism of competition and carbon fouling. Carbon fouling was found reducing adsorption capacity much more intensively than competition by organics. Acidic bulk solution was slightly helpful for adsorption of PFCs. However adsorption velocity or kinetics was not affected by NOM and pH significantly. GAC from Wako Company showed the best performance among four kinds of GACs, and Filtra 400 from Calgon Company was considered more suitable to removal all PFCs among the commercial GACs. Preliminary RSSCT and SBA results implied that background organics broke through fixed GAC bed much earlier than trace level of PFCs. Medium-chained PFCs can be effectively removed by fixed bed filtration without concerning biological processes. 　Direct photolysis process has been developed in chapter VI to decompose PFCAs in river water. Irradiation at UV254 nm and UV254+185 nm can both degrade PFCAs. Stepwise decomposition mechanism of PFCAs was confirmed by mass spectra analysis, and consecutive kinetics was proposed to simulate experimental data. PFASs can also be degraded by UV254+185 photolysis, although the products have not been identified yet. Coexisted NOMs reduced performance of UV photolysis for PFCAs by competition for UV photons. Sample volume or irradiation intensity showed significant influence on degradation of PFCAs. Local river water polluted by PFOA can be cleaned up by UV254+185 photolysis effectively. Ozone-related processes were also studied but ineffective to degrade PFC molecules. However, PFCs could be removed in aeration flow by another mechanism.
京都大学
0048
新制・課程博士
博士(工学)
甲第13340号
工博第2837号
新制||工||1417(附属図書館)
UT51-2007-M963
京都大学大学院工学研究科都市環境工学専攻
(主査)教授田中宏明, 教授藤井滋穂, 教授伊藤禎彦
学位規則第4条第1項該当
Doctor of Engineering
Kyoto University
DFAM

Los estilos APA, Harvard, Vancouver, ISO, etc.

30

Morsillo, Sandrine. "Cahier du jour : le sujet artistique par relais d'identité". Paris 1, 1996. http://www.theses.fr/1996PA010578.

Texto completo

Resumen

À partir d'une pratique plastique sur des cahiers d'écoliers effectués en relais par un jeu d'identités multiples, nous interrogeons la posture identitaire de l'artiste dans l'art contemporain (Boltanski, Gasiorowski, Le Gac, Messager). Nous tentons d'analyser les différents regards que porte l'artiste sur son travail pendant l'élaboration de celui-ci (tantôt dans l'œuvre, tantôt hors de celle-ci) puis les différentes phases qui permettent à l'artiste de se constituer en tant que tel (régression, progression et transgression). Enfin, nous terminons par la signature (non-signature et importance de la signature dans l'art) pour démontrer le caractère indispensable de la compromission de l'auteur et la nécessité de l'affirmation d'une identité par rapport à l'œuvre
Through plastic operations that are carried out on pupils'notebooks, which are created through relays in a play on multiple identities, we call into question the position that defines the identity of the artist in the contemporary art (Boltanski, Gasiorowski, Le Gac, Messager). We try to analyse the differents ways in which the artist looks upon her work during its elaboration (sometimes from within the work, sometimes from without), and we investigate the different steps that enable the artist to constitute herself as such (regression, progression and transgression). Finally, we close our study with an analysis of the question of the signature (the nonsignature and the importance of signature in art) in order to show that the author's commitment is an absolute requirement, as is the assertion of the artist's identity in relation to the work

Los estilos APA, Harvard, Vancouver, ISO, etc.

31

Rosenzweig, Shirley Ferreira. "Adsorption of Copper (II) on Functionalized Carbon Nanotubes (CNT): A study of adsorption mechanisms and comparative analysis with Graphene Nanoplatelets (GNP) and Granular Activated Carbon (GAC) F-400". University of Cincinnati / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1368026548.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

32

Quoi, Alexandre. "Histoire(s) du narrative art (1965-1981) : récits photoconceptuels et formes hybrides du médium photo-texte". Thesis, Paris 4, 2011. http://www.theses.fr/2011PA040151.

Texto completo

Resumen

Marquée par le pluralisme, la décennie 1970 a vu apparaître l’étiquette « Narrative Art » regroupant de nouvelles pratiques conceptuelles, orientées vers la subjectivité et la transmission de récits, qui combinent photographie et texte. Cette étude retrace pour la première fois l’histoire de cette mouvance internationale encore méconnue et mal définie. L’analyse de sa fortune critique et l’observation de ses différents contextes d’émergence, en Europe et aux États-Unis, vise à dégager la spécificité d’un champ de recherche révélant une sensibilité de l’époque, où l’identité, la mémoire, l’autobiographie et la fiction constituent des thèmes dominants. Il s’agit également de mettre l’accent sur l’articulation polysémique de l’image et du langage au sein du dispositif photo-texte, une forme hybride qui se prête à de multiples manipulations et modes de diffusion. Les œuvres rattachées au Narrative Art invitent par ailleurs à réfléchir aux mutations introduites par le photoconceptualisme. En investissant les ressources formelles de la photographie, ces expérimentations traduisent le passage d’une assimilation du style documentaire et amateur à une attention esthétique grandissante qui renoue avec le paradigme pictural. Cette prolifération des usages artistiques du médium photographique a généré une investigation soutenue de ses propriétés et conventions, qui a contribué simultanément à interroger son objectivité et à accélérer son institutionnalisation
Marked by pluralism, the Seventies witnessed the appearance of the label « Narrative Art » uniting new conceptual practices, oriented towards subjectivity and the transmission of stories, which combine photography and text. This study recounts for the first time the history of this international trend still misunderstood and ill-defined. The analysis of its critical fortunes and the observation of its different contexts of emergence, in Europe and in the United States, aims to bring out the specificity of a research field revealing the sensitivity of the period, for which identity, memory, autobiography and fiction constitute prevailing themes. It is also the matter of stressing on the polysemous articulation of image and language within the photo-text scheme, a hybrid form which lends itself to numerous manipulations and modes of diffusion. Moreover, the works attached to Narrative Art induce to consider the mutations introduced by photoconceptualism. In investing the formal resources of photography, these experiments convey the shift from an assimilation of the documentary and amateur style to a growing aesthetic attention which takes up again with the pictoral paradigm. This proliferation of the artistic uses of the photographic medium has generated a sustained investigation of its characteristics and conventions, which has contributed simultaneously to question its objectivity and to accelerate its institutionalization

Los estilos APA, Harvard, Vancouver, ISO, etc.

33

Hatt, Juliette W. "Pretreatment options for municipal wastewater reuse using membrane technology". Thesis, Cranfield University, 2012. http://dspace.lib.cranfield.ac.uk/handle/1826/10200.

Texto completo

Resumen

Increasing freshwater scarcity across the world means that wastewater reclamation is being considered as a key method in which to meet the growing demand. Evolution of water reuse schemes where high quality product is required such as for indirect potable reuse has led to the adoption in recent years of the integrated membrane scheme using a combination of microfiltration or ultrafiltration with reverse osmosis membrane. However, despite technological advancements, these membranes are still prone to fouling resulting in increased costs through cleaning or replacement. This thesis aims to look at pretreatment to reduce the fouling propensity of the microfiltration membranes via a 600m3 /d pilot plant which was commissioned to investigate indirect potable reuse. A range of pretreatments including pre-screening, pre-coagulation, powdered activated carbon and granular activated carbon were assessed based on fouling amelioration, water quality improvement and cost analysis. Results showed that ferric sulphate dosing was the most effective in terms of reducing the reversible fouling rate especially at high turbidity loads enabling higher flux to be realised leading to a small cost benefit. Activated carbon proved the most effective pretreatment in terms of organic removal and a significant reduction in the irreversible fouling rate. However, the cost involved in using this as a pretreatment is significant compared to possible cost savings through reduced requirement for chemical cleaning. This pretreatment is only viable if it obviates the need for a separate organic removal process.

Los estilos APA, Harvard, Vancouver, ISO, etc.

34

Liu, Xingjian. "Membrane Electrochemical Treatment of Landfill Leachate: Processes, Performance and Challenges". Diss., Virginia Tech, 2020. http://hdl.handle.net/10919/105173.

Texto completo

Resumen

Landfilling is the most common approach to dispose of municipal solid wastes but inevitably leads to leachate formation. Persistent UV quenching substances (UVQS) in landfill leachate can affect the effectiveness of UV disinfection in municipal wastewater treatment systems when leachate co-treatment is applied. Membrane electrochemical reactor (MER) treatment was investigated to reduce the UV quenching capability and simultaneously recover resources in the leachate as an effective onsite pre-treatment. Ion-selective membranes were used in this MER to create two different conditions: a low-pH anolyte for organic oxidation and a high-pH catholyte for ammonia recovery. The MER achieved significantly higher removals of both dissolved organic carbon and UV254nm absorbance than membrane-less electrochemical treatment. The MER was able to remove a large percentage of total nitrogen from the leachate while recovering about half of the influent ammonia in the catholyte with less specific energy consumption. The second study coupled MER with Fenton oxidation through providing synergistic benefits with the low solution pH, reduced organics, and ammonia removal. This two-stage coupled system reduced the more leachate COD than the standalone Fenton process treating raw leachate. Also, the usage of chemicals as Fenton reagents has been greatly reduced: FeSO4 and H2O2 by 39%, H2SO4 by 100%, and NaOH by 55%. Consequently, the sludge production was reduced by 51% in weight and 12% in volume. Despite electricity consumption by the MER, the coupled system cost $4.76 per m3 leachate less than the standalone Fenton treatment. More notably, direct Fenton oxidation removed only 21% of ammonia; in comparison, the MER-Fenton system removed ammonia by 98% with the possibility for recovery at a rate of 30.6 -55.2 kg N m-3 reactor d-1. Those results demonstrated that coupling MER with the Fenton process could mitigate some inherent drawbacks of Fenton oxidation such as ineffective ammonia removal, high acid and chemical reagents dose requirements, and a large amount of sludge generation. The third study investigated the formation of total halogenated organics (DBP) and the associated toxicity as the side effect of leachate treatment in the MER. Compared to the 4538±100 µg L-1 from the control membrane-less electrochemical oxidation reactor, the amount of DBP generated in the MER only accounted for 19.1±4.5 % after the same treatment period. The total toxicity value (26.6 ×10-3 ) was low for MER effluent, only 15.1% of that in the control group. Both high pH and high ammonia concentration introduced more DBP mass and toxicity production after MER treatment. DBP concentrations were shown to increase with applied current density and possible temperature raise. With 67.5% of DBP mass concentration and 74.4% of the additive toxicity removal, the granular activated carbon (GAC) electrode system was shown more effective than GAC adsorption alone in remediating DBP harmful effects. This dissertation introduced MER as a promising technology for the treatment of leachate through performance demonstration, process integration and by-product remediation.
Doctor of Philosophy
Municipal solid waste is often disposed of in landfills because of the most economics and convenience. However, one of the most challenging problems is the leachate formation and treatment. In the US, leachate is currently often diluted in domestic wastewater treatment systems; meanwhile, the persistent contaminants in landfill leachate can lower the effectiveness of UV disinfection and result in high cost and permit violation. In this study, the membrane electrochemical reactor (MER) using electricity as the driving force was applied to solve the issue and simultaneously recover valuable resources in the leachate. Membranes as a barrier for selective ions were used in this MER to create two different conditions with different purposes: a low-pH anolyte for organic oxidation and a high-pH catholyte for ammonia recovery. The MER achieved significantly higher contaminants removals than membrane-less electrochemical treatment. The second study coupled MER with one of the established advanced oxidation processes, also known as Fenton oxidation through providing mutual benefits with the low solution pH, reduced organics, and ammonia removal/recovery. This two-stage coupled system reduced the leachate contaminants effectively towards the direct discharge standard. In addition, the usage of chemical reagents, as well as the amount of process residual, has significantly been reduced. The third study investigated the formation of by-products as the side effect of leachate treatment in the MER. Compared to the membrane-less reactor, the undesirable by-products generated in the MER only accounted for one fifth after the same treatment period. A granular activated carbon electrode system was shown effective in remediating the harmful effects. This dissertation introduced MER as a promising technology for the treatment of leachate as one of the toughest wastewaters.

Los estilos APA, Harvard, Vancouver, ISO, etc.

35

DAVEL, JAN L. "BIODEGRADATION OF THE ENERGETIC COMPOUNDS TNT, RDX AND HMX IN FLUIDIZED-BED AND ACTIVATED SLUDGE REACTORS". University of Cincinnati / OhioLINK, 2003. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1035234722.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

36

Pereira, Claudia Mota Santos. "Comportamento de sistemas pós-filtros adsorvedores na remoção de compostos orgânicos precursores e subprodutos da desinfecção". Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/3/3147/tde-14102009-104609/.

Texto completo

Resumen

O presente trabalho teve como objetivo avaliar a eficiência de pós-filtros adsorvedores constituídos de Carvão Ativado Granular (CAG) na remoção de compostos orgânicos precursores e na formação de subprodutos da desinfecção, em particular dos trialometanos (THM) na Estação de Tratamento de Água Alto da Boa Vista (ETA ABV), abastecida por reservatórios de água bruta com elevado grau de eutrofização. Os ensaios foram conduzidos em ETA Piloto composta por tanque de reservação de água filtrada, ozonizador, tanque de reservação de água ozonizada e 4 pós-filtros adsorvedores, sendo duas unidades dotadas de CAG de origem mineral e duas unidades dotadas de CAG de origem vegetal. Os filtros foram operados em paralelo, sendo que duas colunas foram alimentadas com água filtrada da ETA ABV (Filtro F3 CAG de origem mineral e Filtro F4 CAG de origem vegetal) e as outras duas alimentadas com água filtrada e ozonizada (Filtro F1 CAG de origem mineral e Filtro F2 CAG de origem vegetal). A avaliação da remoção de compostos orgânicos precursores e formação de subprodutos da desinfecção foi feita através de análises de carbono orgânico total (COT), UV-254 nm e formação de THM. A análise dos resultados gerados de julho de 2007 a dezembro de 2008 permitiu concluir que 93% do THM é formado nas primeiras 24 horas de contato da amostra com o cloro, simulando a pós cloração e pós alcalinização da ETA ABV. O processo de oxidação por ozônio não foi efetivo na remoção de THM instantâneo, visto que a média dos 38 valores de THM instantâneo para a água filtrada (17,8 ± 5,6 g/L) foi igual a média obtida para o THM instantâneo na água ozonizada. A remoção de THM pelos filtros de CAG foi mais significativa nos primeiros três meses de operação do sistema, apresentando remoção de 80% para os filtros com CAG de origem mineral e 70% para os filtros com CAG de origem vegetal, a partir do quarto mês de operação do sistema a remoção de THM caiu para um valor médio de 34%, o que mostra uma iminente saturação do leito adsorvedor. Os pós-filtros adsorvedores constituídos de CAG de origem mineral apresentaram melhor comportamento com respeito a remoção de THM e COT quando comparado com os pós-filtros dotados de CAG de origem vegetal.
The main purpose of this work was to evaluate the performance of a Granular Activated Carbon (GAC) post-filter adsorbers in the removal of organic precursors and in the formation of disinfection byproducts, especially trihalomethanes (THM) in Alto da Boa Vista Water Treatment Plant (ABV WTP), which takes raw water from a highly eutrophized reservoirs. The tests was conducted on a Pilot WTP composed of filtered water tank, ozonator, ozonized water tank, and four post-filter adsorbers: two units with mineral GAC media and two units with vegetal GAC media. The filters were operated in parallel, with two columns fed with filtered water from ABV WTP (F3 Filter mineral GAC and F4 Filter vegetal GAC) and the other fed with ozonized water (F1 Filter mineral GAC and F2 Filter vegetal GAC). The evaluation of the removal of organic precursors and the formation of disinfection byproducts was made through analysis of Total Organic Carbon (TOC), UV-254 nm and THM formation. The results generated from July 2007 to December 2008 showed that 93% of THM is formed in the first 24 hours of contact with the chlorine in the sample, simulating the post chlorination and post alkalinization of ABV WTP in samples of filtered water, ozonized water, and post-filter adsorbers effluent. Ozone oxidation process was not effective in removing THM. Was found the same instantaneous THM values in the filtered water (17.8 g/L± 5.6 g/L) and in the ozonized water. During the first three months of post-filter adsorber operation, THM removal efficiencies were around 80% for F1 and F3 (mineral GAC media) and around 70% for F2 and F4 (vegetal GAC media). After four months of operation, THM removal efficiencies decreased to 34% average value, thus indicative of GAC saturation. Regarding THM and TOC removal efficacy, the mineral GAC performed better than the vegetal GAC.

Los estilos APA, Harvard, Vancouver, ISO, etc.

37

Datysgeld, Mark William [UNESP]. "O papel da Governança da Internet dentro da Governança Global: Um estudo de caso da ICANN". Universidade Estadual Paulista (UNESP), 2017. http://hdl.handle.net/11449/151066.

Texto completo

Resumen

Submitted by MARK WILLIAM DATYSGELD null (markwdt@gmail.com) on 2017-06-28T08:14:16Z No. of bitstreams: 1 Dissertacao mestrado Mark-Final-1.pdf: 1155264 bytes, checksum: 2746bbe3837cd33a3221403026d8f0a8 (MD5)
Rejected by Luiz Galeffi (luizgaleffi@gmail.com), reason: Solicitamos que realize uma nova submissão seguindo a orientação abaixo: O arquivo submetido está sem a ficha catalográfica. A versão submetida por você é considerada a versão final da dissertação/tese, portanto não poderá ocorrer qualquer alteração em seu conteúdo após a aprovação. Corrija esta informação e realize uma nova submissão com o arquivo correto. Agradecemos a compreensão. on 2017-06-28T20:32:21Z (GMT)
Submitted by MARK WILLIAM DATYSGELD null (markwdt@gmail.com) on 2017-07-06T16:36:02Z No. of bitstreams: 1 Dissertacao mestrado Mark-Final.pdf: 1072549 bytes, checksum: ed07ad610faed62cd8293f9a5d8c5c19 (MD5)
Approved for entry into archive by LUIZA DE MENEZES ROMANETTO (luizamenezes@reitoria.unesp.br) on 2017-07-12T20:42:51Z (GMT) No. of bitstreams: 1 datysgeld_mw_me_mar.pdf: 1072549 bytes, checksum: ed07ad610faed62cd8293f9a5d8c5c19 (MD5)
Made available in DSpace on 2017-07-12T20:42:51Z (GMT). No. of bitstreams: 1 datysgeld_mw_me_mar.pdf: 1072549 bytes, checksum: ed07ad610faed62cd8293f9a5d8c5c19 (MD5) Previous issue date: 2017-05-10
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
O termo governança global tomou nova forma na Governança da Internet, onde a maior parte das instituições utiliza-se do modelo multistakeholder, formando espaços de diálogo e processos decisórios com diversos atores, sejam estes estatais, privados, civis ou acadêmicos. Propõe-se então a análise do estudo de caso da ICANN, instituição responsável pela administração dos contratos relacionados à regulação do uso dos Nomes e Números, o DNS. Por meio de leitura acadêmica, jornalística, pesquisa de campo, participação em conferências e entrevistas com pessoas relevantes à área. Procedeu-se a elaboração, utilizando-se do material dessas diversas fontes, de um panorama da contextualização da revolução tecnológica que levou à Internet atual, e também da governança global. Posteriormente, passou-se para o ecossistema de Governança da Internet como conceito e prática. Assim, o estudo de caso está inserido em um contexto maior, de modo que se possa compreendê-lo em seus intrincados pormenores. Ao contrário da maioria das instituições transnacionais, que acabam por ter caráter recomendativo, na ICANN as decisões são realmente efetuadas. Apesar de o modelo multistakeholder propor igualdade entre os atores, alguns possuem maior influência. Antes da Transição IANA, os Estados Unidos tinham um peso muito maior, agora largamente ocupado pelo setor privado. A Governança da Internet é única dentro da governança global. Esta deve sua distinção a algumas possíveis razões, como o desenho técnico da Internet. Portanto, há grande possibilidade de este não ser um modelo reprodutível em outras áreas. O modelo multistakeholder apresenta um modo divergente de avaliar-se as relações entre atores no Sistema Internacional e o limite do poder do Estado. Mesmo que não haja continuidade no modelo atual, o campo de estudos é extenso e ainda longe de alcançar sua maturidade.
The term global governance has taken a new form in Internet Governance, where most institutions use the multistakeholder model, forming spaces for dialogue and decision-making processes with various actors, including states, companies, civil society or academia. An analysis of the ICANN case study, the institution responsible for administering contracts related to the regulation of the use of Names and Numbers, the DNS, is then proposed. The research was done through academic reading, journalism, field research, participation in conferences and interviews with people relevant to the area. With the material from these various sources, it was elaborated a panorama of the technological revolution contextualization that led to the Internet as it is today, as well as to global governance. Subsequently, we moved on to the Internet Governance ecosystem as a concept and practice. Thus, the case study is embedded in a larger context, so that one can understand it in its intricate details. Unlike most transnational institutions, which are deliberation bodies, ICANN decisions are actually carried out. Although the multistakeholder model proposes equality among the actors, some have greater influence. Prior to the IANA Transition, the United States had a much greater weight, now largely occupied by the private sector. Internet Governance is unique within global governance. It owes its distinction to some possible reasons, such as the technical drawing of the Internet. Therefore, there is a great possibility that this is not a reproducible model in other areas. The multistakeholder model presents a divergent way of assessing the relations between actors in the International System and the limit of state power. Even if there is no continuity in the current model, the field of study is extensive and still far from reaching maturity.

Los estilos APA, Harvard, Vancouver, ISO, etc.

38

Skoglund, Oskar. "Evaluation of bark material and granulated active carbon for treatment of perfluoroalkyl substances (PFASs) in wastewater". Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-317453.

Texto completo

Resumen

Per- and polyfluoroalkyl substances (PFASs) are a group of artificial chemicals which have been used in a wide area of applications such as surface protection agents in cloths and different industrial applications. It has been found that PFASs are potentially toxic and are frequently found in the environment due to their persistent and mobile properties. Effluents from wastewater treatment plants (WWTPs) have been identified as an important point source of PFASs. Bark, by-product from the paper and wood industry, is a low-cost adsorbent and has the potential to be used as a filter material for PFASs in WWTPs. In this study, the removal of PFASs in wastewater has been investigated using granulated active carbon (GAC) (n = 2) and bark (n = 2) in a pilot scale experiment at Kungsängsverket, Uppsala over a period of five weeks. The specific objects included: i) investigate the influence of flow-rate (10, 30 40 and 60 Ld-1 ) on the removal efficiency of PFASs in the GAC and bark filters, ii) investigate the influence of particle size of bark on the removal efficiency of PFASs and iii) establish what circumstances that potentially promotes removal of PFASs in GAC and bark filters. The results showed that GAC was the most effective method compared to bark, with a reduction of 73-93%, with increasing efficiency under low flow (10-30 L d-1 ) conditions. The removal efficiency of bark was 45% with a particle size of 2-5 mm and under low flow conditions (10-30 L d-1 ), while under high flow conditions (60 L d-1 ) with the same particle size the removal of PFASs was not efficient, instead the total PFAS concentration increased with 40%. In contrast, bark with a particle size of 5-7 mm proved to be not efficient in removing PFASs (removal efficiency = 0%). In general, the removal efficiency increased with smaller particle size of the adsorbent and lower flow rate. The results indicate that bark may be a low-cost alternative in reducing PFASs from wastewater, under certain conditions.
Per- och polyfluroalkyla ämnen (PFAS) är en familj av artificiella fluorerade organiska föreningar som har använts sedan 1950-talet i en rad olika applikationer, såsom impregnering i kläder. Studier har visat att PFAS är potentiellt toxiska och att de förekommer globalt på grund av deras persistenta och mobila egenskaper. Spillvatten från avloppsreningsverk etablerats som en betydande källa för PFAS. Bark, vilket är en biprodukt från pappers- och träindustrin, är ett poröst material vilket möjligen kan användas som adsorbent av PFAS. Denna studie har jämfört effektiviteten hos granulerat aktivt kol (GAC) och bark för att minska PFAS i avloppsvatten. Experimentet var utformat som ett småskaligt kolonn-experiment vid Kungsängsängsverket, Uppsala, och pågick under en fem veckors period. Frågeställningen var att i) studera vilka effekter flödes-hastigheten (10, 30, 40 och 60 L d-1 ) har på reduktionen av PFAS hos GAC och barkfiltren, ii) studera vilka effekter partikelstorleken hos bark har på reduktion av PFAS och iii) redogöra vilka förhållanden som potentiellt gynnar reduktionen av PFAS i GAC och bark filtren. Resultaten visade att GAC var det mest effektiva av de två materialen, med en total reduktion på 73- 93% av PFAS, med ökande effektivitet under låga flödesförhållanden (10-30 L d-1 ). Bark minskade den totala mängden av PFAS med 45% då partikelstorleken var 2-5 mm och under låga flödesförhållanden (10-30 L d-1 ) medan bark med samma partikelstorlek under ökade flödesförhållanden (60 L d-1 ) visade en ökning på 40% av PFAS i det utgående vattnet. Bark med en partikelstorlek på 5-7 mm visade ingen reduktion av PFAS. Generellt visade resultaten att reduktionen av PFAS ökar under låga flödesförhållanden och minskad partikelstorlek. Resultaten visade att bark kan vara ett alternativt material för att minska PFAS i avloppsvatten förutsatt att gynnsamma förhållanden upprätthålls.

Los estilos APA, Harvard, Vancouver, ISO, etc.

39

Villars, Kathryn E. Villars. "Removal of Microcystin-LR from Drinking Water Using Granular Activated Carbon". The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1532007603377473.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

40

Goutière, Vincent. "Comparaison et évaluation de modèles de gaz réels en rayonnement thermique /". Thèse, Chicoutimi : Université du Québec à Chicoutimi, 2000. http://theses.uqac.ca.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

41

Song, Junghui. "Fabrication and Characterization of AlGaN/GaN Heterostructure Devices for Hydrogen Gas Sensing at High Temperature". The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1250296506.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

42

Gao, Ziyao [Verfasser]. "Diamond ultra-small electrodes for integration with GaN electronics / Ziyao Gao". Ulm : Universität Ulm. Fakultät für Ingenieurwissenschaften und Informatik, 2015. http://d-nb.info/107755933X/34.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

43

Modenesi, P. J. "Statistical modelling of the narrow gap gas metal arc welding process". Thesis, Cranfield University, 1990. http://dspace.lib.cranfield.ac.uk/handle/1826/831.

Texto completo

Resumen

The J-laying technique for the construction of offshore pipelines requires a fast welding process that can produce sound welds in the horizontal-vertical position. The suitability of narrow gap gas metal arc welding (NG-GMA W) process for this application was previously demonstrated. The present programme studied the influence of process parameters on the fusion characteristics of NG-GMA welding in a range of different shielding gas compositions and welding positions. Statistical techniques were employed for both designing the experimental programme and to process the data generated. A partial factorial design scheme was used to investigate the influence of input variables and their interaction in determining weld bead shape. Modelling equations were developed by multiple linear regression to represent different characteristics of the weld bead. Transformation of the response variable based on the Cox-Box method was commonly used to simplify the model format. Modelling results were analysed by graphical techniques including surface plots and a multiplot approach was developed in order to graphically assess the influence of up to four input variables on the bead shape. Conditions for acceptable bead formation were determined and the process sensitivity to minor changes in input parameters assessed. Asymmetrical base metal fusion in horizontalvertical welding is discussed and techniques to improve fusion presented. At the same time, the interaction between the power supply output characteristic and the bead geometry was studied for narrow gap joints and the effect of shielding gas composition on both process stability and fusion of the base metal was assessed. An arc instability mode that is strongly influenced by arc length, power supply characteristic and shielding gas composition was demonstrated and its properties investigated. An optimized shielding gas composition for narrow gap process was suggested.

Los estilos APA, Harvard, Vancouver, ISO, etc.

44

Van, Eeden Gert Christian. "The numerical modelling of a flue gas precipitator / G.C. van Eeden". Thesis, North-West University, 2003. http://hdl.handle.net/10394/359.

Texto completo

Resumen

Suspended fly-ash particles in industrial emission gasses have a major degrading effect on the whole environment. Electrostatic precipitation is one of the oldest and most effective gas-cleaning processes used today. Electrostatic precipitators use electrostatic forces to clean the flue gas of ash particles. Stricter emission control laws force industries (like SASOL) to improve their electrostatic precipitators. This study consists of a comprehensive literature survey and the development of a numerical fluid flow model. The proper flow of the gas through an electrostatic precipitator is one of the most important factors to ensure high collection efficiencies. The gas flow must be distributed over the whole flow domain in order to utilize the entire collecting area. The three-dimensional numerical model only considers the fluid dynamics of a precipitator. The finite volume method together with the SIMPLE algorithm is used to solve the fluid dynamic equations. The computer resources available are not sufficient to simulate the full detail of the structures inside a full-scale precipitator. Thus the precipitator flow domain was simplified by making certain assumptions and approximations. The distribution plates in the precipitator inlet ensure good gas distribution through the entire precipitator. Porous baffles are used to approximate the distribution plates and the electrical fields are approximated by porous mediums. The effect of the distribution plates and the electrical fields on the gas flow through the precipitator was investigated. The results have shown that the gas flow was expanded over the whole flow domain and the maximum velocity inside the precipitator was significantly reduced because of the effect of the distribution plates. The simulated gas flow velocity profiles are in relative good agreement with measured velocity profiles. The methodology followed in this study can be used to predict gas flow patterns inside a precipitator but further research is necessary.
Thesis (M.Ing. (Mechanical Engineering))--North-West University, Potchefstroom Campus, 2004.

Los estilos APA, Harvard, Vancouver, ISO, etc.

45

Zbyryn, E. M. "Properties of GaN Films Obtained by Nitridation of Porous GaP (001)". Thesis, Sumy State University, 2012. http://essuir.sumdu.edu.ua/handle/123456789/34882.

Texto completo

Resumen

With the help of nitridation of porous GaP (001) in nitrogen plasma thin films of cubic-GaN were obtained. The conclusion was made that the quality of the GaN films is dependent on the degree of porosity of the GaP substrate. XPS spectra were used to investigate the chemical composition of porous GaP substrates, obtained by electrochemical etching. From XPS measurement we determined that the annealing in atomic nitrogen leads to the formation of GaN films. X-ray diffraction measurements show that cubic GaN on porous GaP substrate has no tensile strain When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/34882

Los estilos APA, Harvard, Vancouver, ISO, etc.

46

Yavuz, Perin Emel. "Narrative art : de l'expérience du monde quotidien à l'œuvre. Herméneutique de l'événement esthétique". Paris, EHESS, 2013. http://www.theses.fr/2013EHES0107.

Texto completo

Resumen

Lorsque le galeriste new-yorkais John Gibson, figure en pointe de la scène américaine des années 1960-1970, organisa les expositions Story I (1973) et Narrative II (1974), il avait perçu ce qui serait « le prochain truc » en vogue après l'Ecologic art et le Body art : la narrativité. Si le Narrative art est tombé dans l'oubli, cette perception qui reposait sur un noyau dur d'artistes américains et européens (Le Gac, Bay, Baldessari, Wegman, Askevold, Hutchinson, Beckley, Welch. . . ) préoccupés par des problématiques narratives aux moyens de la photographie et du texte fut confirmée par une période intense de production critique et d'expositions sur l'ancien et le nouveau continents mais aussi par l'ensemble de la création en quête d'émancipation à l'égard des questionnements essentialistes sur l'art et engagée dans « la fabrique du monde» à laquelle la fonction anthropologique de la narrativité apportait un moyen naturel. Interrogeant et spécifiant, le fait narratif dans ce corpus caractérisé par l'immanence d'un rapport au monde et à soi, par le truchement de la perception esthétique du quotidien et la mythologisation du sujet, cette thèse s'attache à déceler, dans une perspective herméneutique ancrée sur la notion d'événement, les étapes du processus qui mène de l'expérience vive du monde au monde de l'œuvre, de la vie à l'art. Plus qu'une simple histoire du Narrative art, cette thèse interdisciplinaire se présente comme une investigation dans le sens historique, esthétique et politique que revêt le réinvestissement de la narrativité par ces artistes et plus généralement ceux de cette période, décelant les origines de la mésestime de la narrativité par l'histoire de l'art
When the New York galerist John Gibson, leading figure of the American art scene from 1960s-1970s, organized the exhibition Story I (1973) and Narrative II (1974 ), he had seen what would be the "next big thing" in vogue after Ecologic art and body art : narrativity. 1f the Narrative art is now somewhat forgotten, this perception, based on a core of American and European artists (Le Gac, Bay, Baldessari, Wegman, Askevold, Hutchinson, Beckley, Welch. . . ) who were concerned with narrative issues by photography and text means, was confirmed by an intense period of critical production and exhibitions on the old and the new continents. But it was also testified by the whole of creation seeking emancipation against essentialist questionings about art and engaged in "the factory of the world" for which the anthropological function of narrative brought a natural way. Querying and specifying, with narratology, the narrative fact in this corpus which is characterized by the immanence of a relationship to the world and to the self, through the aesthetic perception of the everyday and the mythologizing of the subject, this thesis aims to identify, in a hermeneutic perspective anchored on the notion of event, the steps of the process leading from the living experience of the world to the world of artwork, from life to art. More than just a history of Narrative art, this interdisciplinary thesis is an investigation into the historical, aesthetic and political history meaning given to the reinvestment of narrativity by these artists and more generally those from 1960s-1970s. This investigation allows particularly to identify why narrativity has been so underestmated

Los estilos APA, Harvard, Vancouver, ISO, etc.

47

Okayama, Taizo. "Performance of devices made of large band-gap semiconductors, SiC and GaN". Fairfax, VA : George Mason University, 2007. http://hdl.handle.net/1920/2935.

Texto completo

Resumen

Thesis (Ph. D.)--George Mason University, 2007.
Title from PDF t.p. (viewed Jan. 21, 2008). Thesis director: Mulpuri V. Rao. Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Electrical and Computer Engineering. Vita: p. 128. Includes bibliographical references (p. 122-127). Also available in print.

Los estilos APA, Harvard, Vancouver, ISO, etc.

48

Gad, Alaaeldin [Verfasser]. "Solar Diodes: Novel Heterostructured Materials for Self-Powered Gas Sensors / Alaaeldin Gad". München : Verlag Dr. Hut, 2013. http://d-nb.info/1045987670/34.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

49

Pedreiras, Catarina Alves Reis. "Análise de risco na ótica de gestão: o caso da Poceram Norte". Master's thesis, 2018. http://hdl.handle.net/10400.26/27849.

Texto completo

Resumen

O ambiente atual em que as empresas se inserem é cada vez mais incerto e estão sujeitas a inúmeros riscos que os gestores têm de ser capazes de minimizar. Deste modo, o administrador poderá recorre ao apoio de algumas ferramentas que lhe permitem minimizar o risco e trazer alguma segurança na realização de operações do seu quotidiano. Inicialmente ir-se-á proceder à descrição da empresa, das tarefas desempenhadas no decurso do mesmo. Posteriormente, procede-se à explicação do conceito risco, à descrição de algumas das formas de o gerir e também alguns instrumentos que o podem minimizar. Por fim, é feita uma análise do desempenho económico e financeiro da empresa e far-se-á uma análise de risco desta, com o objetivo de avaliar a sua saúde financeira, no período decorrente entre os anos de 2014 a 2016. Adicionalmente, procurase apreciar como se encontra, face às suas concorrentes, no contexto do setor de atividade onde opera. Termina-se com uma breve conclusão onde são inseridas as principais ilações e outros aspetos considerados pertinente durante o processo de elaboração desta dissertação. Em particular, procurar-se-á mostrar como esta experiência permitiu não só aplicar todo o conhecimento que foi lecionado ao longo do curso, bem como conviver de perto com a realidade empresarial.

Los estilos APA, Harvard, Vancouver, ISO, etc.

50

Tran, Thao Hoang, University of Western Sydney, College of Health and Science y Centre for Plant and Food Science. "Producing carotenoid-rich powder from Gac fruit". 2007. http://handle.uws.edu.au:8081/1959.7/19013.

Texto completo

Resumen

Gac (Momordica Cochinchinensis Spreng or Muricia Cochinchinensis Spreng) is an indigenous fruit of Vietnam, commonly used as a colourant in traditional dishes. Recent studies showed that this fruit had a high carotenoid content, especially lycopene and β-carotene. These carotenoids are currently in high demand as they are natural antioxidants to prevent and treat cancers. Over the last ten years some new products from Gac fruit have been found on the market but the cultivation and consumption of the fruit is still limited. Gac is harvested seasonally and the post harvest processing has not been well developed. To make the best use of the valuable substances in Gac, this project investigated some processing methods to make Gac powder and developed the product quality analyses, potentially applicable to local small-scale manufacture. In order to evaluate the efficiency of the Gac powder process and some of the most important qualities of the Gac powder products, the analytical methods to determine lycopene and β-carotene were developed and validated in this project. The new HPLC-based method included a liquid-liquid extraction, followed by a solid phase extraction before the analysis. Both newly- developed HPLC and SP methods exhibited a high extraction yield, good recovery and reproducibility. Compared with the HPLC, the SP method gives higher mean values and standard deviations, but it is quicker, simpler, less expensive and still reliable for industrial applications due to the use of less toxic solvents. The production of powder from Gac fruit included two main stages: seed removal and aril dehydration. Derived from the same drying operation, the enzymatic-treated Gac powder had a lower carotenoid content compared to the heat-treated powder. The Gac powder produced by the freeze-drying method had the highest carotenoid level and brightest colour. Finally the orange-red Gac powder with high carotenoid content was added to some foods as a colorant and nutrient supplement to illustrate its applications. The colours of foods were significantly improved and the carotenoid contents were increased after processing, indicating a potential market for the Gac powder.
Master of Science (Hons)

Los estilos APA, Harvard, Vancouver, ISO, etc.

Tesis sobre el tema "Gac"

Crea una cita precisa en los estilos APA, MLA, Chicago, Harvard y otros