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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
451

Estrutura da comunidade de invertebrados bentônicos sésseis e suas interações com as vieiras Nodipecten nodosus no cultivo da Praia do Canto Grande, Santa Catarina

Carraro, João Luís de Fraga January 2008 (has links)
O cultivo de moluscos marinhos tornou-se, nos últimos dez anos, uma importante fonte de renda das comunidades litorâneas de Santa Catarina, no sul do Brasil, sendo este estado o maior produtor nacional de moluscos cultivados e o segundo maior da América do Sul. A vieira Pata-de-Leão (Nodipecten nodosus Linnaeus, 1758) é uma espécie com grande potencial para a aqüicultura, e seu cultivo em escala experimental e piloto vem sendo realizado em Santa Catarina, com excelentes perspectivas. Entretanto, a incidência de organismos epibiontes sobre as valvas das vieiras cultivadas em Santa Catarina, por períodos superiores a quatros meses, pode acarretar problemas no desenvolvimento dos moluscos, uma vez que há interferência no crescimento em altura da N. nodosus (RUPP, 2007). O presente trabalho teve como objetivos registrar a ocorrência dos principais organismos que compõem o fouling da vieira N. nodosus e se este assentamento acarreta efeitos negativos no seu desenvolvimento; identificar e descrever as espécies de esponjas presentes no fouling e avaliar de forma preliminar a capacidade de colonização das espécies de esponjas através da competição por espaço com outros organismos da epifauna. As coletas foram realizadas no cultivo de vieiras N. nodosus, situado no estado de Santa Catarina, município de Bombinhas, praia do Canto Grande (27o13’S/48o30’W), nos meses de junho de 2006 a julho de 2007. Foi detectada a presença de 31 espécies pertencentes a sete grandes grupos de organismos epibiontes. Dessas, apenas dez espécies representaram mais de 98% da abundância total. Apesar de haver aumento da riqueza de espécies, diferenças na abundância e na diversidade ao longo das coletas, não houve evidências concretas de processos sucessionais. Após 467 dias sem limpeza, as vieiras do cultivo de Canto Grande não apresentaram efeitos negativos pela presença do fouling. Foram registradas oito espécies de esponjas, sendo Arenosclera brasiliensis a mais abundante, e Prosuberites sp. a espécie que apresentou a maior área de cobertura das valvas das vieiras. Entretanto, nenhuma espécie foi dominante na comunidade de epibiontes, não evitando a presença de outros organismos incrustantes. Foram identificadas pela primeira vez, esponjas associadas às vieiras de cultivo, descrevendose oito espécies: Arenosclera brasiliensis Muricy & Ribeiro 1999, Tedania ignis (Duhassaing & Micheloti, 1864), Lissodendoryx (Lissodendoryx) isodictyalis (Carter 1882), Hymeniacidon heliophila Parker 1910, Mycale (Carmia) microsigmatosa Arndt 1927, Halichondria (Halichondria) sp., Mycale (Carmia) sp. e Prosuberites sp. Ampliam-se os limites meridionais de A. brasiliensis e L. isodictyalis. Mycale sp. e Prosuberites sp. são possíveis espécies novas para a ciência. / The cultivation of marine mollusks became, in the last ten years, a major source of income to the coastal communities of Santa Catarina in southern Brazil. This state is the greatest domestic producer of shellfish cultivation and the second largest in South America. The scallop Pata-de-Leon (Nodipecten nodosus Linnaeus, 1758) is a species with great potential for aquaculture, and its cultivation in experimental and pilot scale is being held in Santa Catarina, with excellent prospects. However, the incidence of epibionts on the valves of scallops can cause problems in the development of bivalves. This study aimed to identify the occurrence of the main organisms that make up the fouling of the scallop N. nodosus and whether this settlement would impose negative effects on their development; to record and describe the occurrence of eight species of marine sponges associated with cultured scallops and evaluate on a preliminary form the ability of colonization of sponges species by the space competition with others epifaunal organisms. The samples were collected in the cultivation of scallops N. nodosus, located in the state of Santa Catarina, municipality of Bombinhas, the beach Canto Grande (27°13'S / 48°30'W), in the months of June 2006 to July 2007. It detected the presence of 31 species belonging to seven major groups of organisms epibionts. Of these, only ten species represented more than 98% of the total abundance. Although there was an increase in species richness, differences in the abundance and diversity throughout the study period, there was no concrete evidence of successional processes. After 467 days without cleaning, the scallops of the culture of Canto Grande showed no negative effects by the presence of fouling. Eight sponge species have been recorded being the most abundant Arenosclera brasiliensis, and Prosuberites sp. the species that showed the largest area of coverage valve of the scallops. However, no species was dominant in the community of epibionts, not avoiding the presence of other organisms incrustants. All sponge species have been described: Arenosclera brasiliensis Muricy & Ribeiro 1999, Tedania ignis (Duhassaing & Micheloti, 1864), Lissodendoryx (Lissodendoryx) isodictyalis (Carter 1882), Hymeniacidon heliophila Parker 1910, Mycale (Carmia) microsigmatosa Arndt 1927, Mycale (Carmia) sp., Halichondria (Halichondria) sp. e Prosuberites sp. The southern boundaries of A. brasiliensis and L. isodictyaliz were enlarged and the latter is a new record for Brazilian coast. Mycale sp., Halichondria sp. and Prosuberites sp. are possible new species.
452

Remoção de nitrogênio e material orgânico via nitrificação e desnitrificação simultânea (NDS) em biorreator de membranas submersas com biofilme (BRMS-BF) para o tratamento de águas urbanas servidas

Salcedo, Alvaro Javier Moyano January 2018 (has links)
Orientador: Prof. Dr. Eduardo Lucas Subtil / Dissertação (mestrado) - Universidade Federal do ABC, Programa de Pós-Graduação em Ciência e Tecnologia Ambiental, Santo André, 2018. / O lançamento de águas urbanas servidas (AUS) sem tratamento causa problemas associados à saúde pública e à deterioração dos recursos hídricos. Neste contexto, os Biorreatores com Membranas Submersas (BRMS) e Biofilme (BRMS-BF), operados sob condições específicas para nitrificação e desnitrificação simultâneas (NDS), são uma opção viável para o tratamento de água AUS e seu potencial reúso. Este projeto de pesquisa teve como objetivos avaliar a remoção de nitrogênio via NDS, caracterizar o processo de fouling das membranas e identificar os principais microrganismos associados ao ciclo do nitrogênio em um sistema piloto BRMS-BF operado em diferentes concentrações de oxigênio dissolvido (OD) para o tratamento de AUS. O volume útil do reator foi de 156 L com módulo de 17 membranas (sintetizadas em fluoreto de vinilideno, PVDF) tipo placa plana de ultrafiltração de 0,1 ?m. O material suporte foi de poliuretano (gel termoplástico). O efluente utilizado foi da residência estudantil e o restaurante universitário da Universidade de São Paulo. Foram propostas duas fases de operação com concentrações de OD acima de 2, e 0,8 mgO2/L. Os valores de temperatura (T), Potencial de Redox (ORP), e pressão transmebranar (PTM) foram monitorados e os de pH, vazão (Q) e OD controlados, por meio de sensores. A aeração foi realizada controlando o fluxo através de rotação por meio de dois difusores de ar de 10 e 15 L/min. Os resultados para a fase I e II apresentaram os valores médios a seguir, respetivamente: T (24 e 23 ?), ORP (186 e -11 mV), PTM (0,02 e 0,04 bar), pH (6,9 e 6,7), Q (22 e 16 L/h), OD (2,2 e 0,9 mgO2/L) e SST (5,7 e 5,6 g/L). A remoção de matéria orgânica (DQO e DBO5 mg/L) e de turbidez foi maior de 96% e de 99%, respetivamente nas duas fases. A remoção de nitrogênio total foi de 33% para a Fase I e 74% na Fase II, apresentando melhoras na remoção a baixa concentração de OD. No entanto, a Fase II apresentou acúmulo de nitirto, que pode estar relacionado com a desnitrificação parcial, devido a ausência de carbono suficiente em presença de baixas concentrações de OD. As comindades de microrganismos observadas perteneceram principalmente ao filo Petrobacteria (abundância relativa > 70% na biomassa suspensa e o biofilme para a Fase I e II). O gênero Nitrospira foi o principal gênero identificado que influenciou o processo de oxidação de nitirito. Não foi encontrada diferença significativa entre os microrganismos presentes segundo o tipo de biomassa e a concentração de OD. Não houve uma redução significativa na permeabilidade das membranas, associada ao fouling, quando a concentração de OD foi reduzida para 0,9 mg/L. / Urban waters served (UWS) without any kind of treatment causes problems which are related to public health and hydric resources deterioration. In this context, the Submerged Membranes Bioreactor (MBRS) and Biofilm (MBRS-BF), operated under specific conditions for simultaneous nitrification-denitrification (SND), are a viable option for UWS treatment and their potential reuse. The aim of this project is to evaluate nitrogen removal via SND, characterize the process of fouling of the membranes and identify the main microorganisms related to nitrogen cycle in a MBRS-BF pilot-system which was operated on different concentrations of dissolved oxygen (DO) for UWS treatment. Reactor useful volume was 156 L with 17-membranes module - (synthesized in a Polyvinylidene Fluoride - PDVF) - 0,1 ?m ultrafiltration flat-plate type. Support material was composed of polyurethane (thermoplastic gel). The used effluent has come as from student residence as USP's food court. Two operation-phases were proposed in which concentration was over 2, and 0,8 mgO2/L. Temperatures values (T), Redox potential (ORP) and trasmembrane pressure(TMP) was monitored as well as pH, leakage (L) and DO was controlled by sensors. Aeration was carried out by controlling flow in rotation through two air diffusers with 10 e 15 L/min capacity. The results for phases I and II performed the following average values, respectively: T (24 and 23), ORP (186 and -11 mV), PTM (0,02 and 0,04 bar), pH (6,9 and 6,7), Q (22 and 16 L/h), OD (2,2 and 0,9 mgO2/L) and SST (5,7 and 5,6 g/L). Organic matters removal (DQO and DBO5 mg/L) and turbidity was bigger, by ranging from 96% to 99%, respectively, in both phases of this operation. Total nitrogen removal was 33% for Phase I and 74% of Phase II, by perfoming best efficiency in concentration of low OD (0,9mgO2/L).However, phase II showed nitrite storage, which can be attributed to partial denitrification, due to absence of carbon enough in OD low concentrations. Observed microorganisms communities belonged to mainly Petrobacteria phylum (relative abundance > 70% in suspended biomass and biofilm for phases I and II). Nitrospira was the main genus found which influenced nitrite oxidation process. It was not found significant difference among these present microorganisms according to their biomass type and DO concentration. There were not any significant reduction on membranes permeability, related to fouling, when DO concentration was reduced to 0,9 mg/L.
453

Caractérisation expérimentale et comportement de constituants protéiques et minéraux laitiers en concentration sous vide / Thermodynamic and hydrodynamic characterization of the vacuum evaporation process during concentration of dairy products in a falling film evaporator

Caldas Pereira Silveira, Arlan 12 October 2015 (has links)
Les évaporateurs à flot tombant (EFT) sont largement utilisés dans les industries chimiques, de la réfrigération, du raffinage du pétrole, et alimentaires. Dans l'industrie laitière, les EFT sont appliqués pour la concentration de solutions avant l'étape de séchage. Malgré l'importance économique du procédé d'évaporation sous vide dans la fabrication de produits laitiers déshydratés, la connaissance du procédé est essentiellement empirique. Des recherches visant à améliorer l'efficacité du procédé sont donc nécessaires. L'objectif de ce projet de doctorat est de caractériser expérimentalement un EFT lors de la concentration de produits laitiers, par des approches thermo et hydro-dynamiques, afin d'étudier les interactions entre les propriétés des produits et les paramètres opérationnels. Un évaporateur à flot tombant, simple effet, à l’échelle pilote, qui décrit le même processus que celui à l'échelle industrielle, d'un point de vue hydrodynamique, a été instrumenté et utilisé pour établir les bilans massiques et énergétiques. La capacité évaporatoire et le coefficient global de transfert de chaleur ont été calculés à partir des données expérimentales. Une méthodologie pour la détermination expérimentale des fonctions distribution des temps de séjour (DTS) a été développée. En effet, les fonctions de DTS fournissent des informations essentielles sur l'écoulement des produits lors de la concentration dans un EFT. L'augmentation de la concentration, du débit massique et de la distance parcourue par le produit entraîne une augmentation de la dispersion des particules dans le flux. Ces fonctions ont été modélisées par une combinaison de réacteurs en cascade, parfaitement agités. D’après l'interprétation de ce modèle, deux flux, un principal et un secondaire, correspondant à deux couches superposées de produit circulant à travers des tubes d'évaporateur, a été proposé. La méthodologie développée pour le calcul des fonctions de DTS a été appliqué pour la concentration de produits laitiers (lait écrémé, lactosérum doux et acide). Par la suite, l'étude a été étendue à la formation de l'encrassement pendant la concentration par évaporation sous vide. Il a été montré que le temps de séjour moyen était plus sensible pour identifier l'encrassement que le coefficient global de transfert de chaleur et la capacité évaporatoire. Ainsi, cette étude a souligné le rôle crucial de l’importance de la caractérisation des EFT sous vide afin d’en améliorer leurs performances et la qualité des produits qui en sont issu. / Falling film evaporators (FFE) are widely used in the chemical, refrigeration, petroleum refining, desalination and food industries. In the dairy industry FFE is applied for the concentration of solutions prior to the drying step. Despite the economic importance of the vacuum evaporation process in the manufacture of dairy dried products, the knowledge about the process is mostly empirical. Research aiming to improve the efficiency of the process is therefore necessary. The objective of this PhD project was to characterize experimentally a FFE during the concentration of dairy products by means of thermodynamic and hydrodynamic approaches, in order to study the interactions between the products properties and the operating parameters. A pilot-scale, single-stage falling film evaporator that describes the same process as that of an industrial scale from a hydrodynamic point of view was instrumented and used to establish the mass and energy balances. The evaporation rate and the overall heat transfer coefficient were calculated from the experimental data to follow up the process. A methodology for the determination of the experimental residence time distribution (RTD) functions was developed. RTD functions provide global information about the flow of the products during concentration in a FFE. Increasing of the concentration of skim milk, mass flow rate and the distance covered by the product resulted in an increase in the dispersion of the products particles. The experimental RTD functions were modelled by a combination of two perfectly mixed reactor tanks in series. From the interpretation of this model, two different flows, a main and a minor flow, were identified. The RTD methodology developed on skim milk was applied to sweet whey and lactic acid whey and the study was extended to the formation of fouling during a 5-hour concentration. The mean residence time was more sensitive to identify fouling than the overall heat transfer coefficient and the evaporation rate. This study emphasized the crucial role of process characterization to improve the performance of FFE and product quality.
454

Etude de la viabilité et de la réactivité d'une biomasse épurative de Bioréacteur à membranes / Study of activated sludge viability and reactivity in membrane bioreactor (MBR)

Pajoum Shariati, Farshid 12 December 2012 (has links)
Les règlements plus stricts pour les rejets d'eaux usées présentent de nouveaux défis technologiques pour le traitement d'eaux usées urbaines et industrielles. Le besoin notamment d‘améliorer la qualité hygiénique de l'eau traitée se fait ressentir en cas de sites sensibles ou de réutilisation. Le bioréacteur à membranes (BRMs) représente une des approches les plus innovatrices pour éviter la présence d'agents pathogènes dans l‘eau en sortie de station. En utilisant des membranes avec un seuil de coupure dans la gamme 0.04~0.2 μm, les bactéries mais aussi les virus sont pratiquement complètement retenus. Si l'encrassement membranaire reste un problème déterminant pour le développement des BRMs, le manque d‘outils de caractérisation en ligne de la qualité et la quantité de biomasse active dans les réacteurs reste un point important pour favoriser le contrôle et l‘optimisation des BRMs. Dans cette étude une méthode originale a été développée pour évaluer la viabilité des boues activées présentes dans un réacteur biologique d‘épuration en complémentarité des informations données par la mesure d'activité respirométrique. Cette méthode permet la distinction entre cellule morte et vivante, la respirométrie pouvant alors distinguée la part active de la biomasse vivante. Le travail expérimental a été conduit dans deux réacteurs biologiques de type chenal d‘oxydation équipés de membranes immergées "airlift oxidation ditch membrane bioreactor" (AOXMBR). Les modules membranaires sont immergés dans un zone aérée où l‘apport d‘air permet à la fois la circulation d‘eau par air-lift, l‘aération du milieu et le nettoyage des membranes par aération. Les essais ont été conduits en mode fermé (batch reactor), alterné (fed batch reactor) et continu. La première partie de l‘étude concerne la caractérisation hydrodynamique du réacteur déterminante en terme de conformité du système pour la circulation des fluides, l‘intensité des transferts et des réactions d‘épuration. Les résultats mettent en avant le rôle de la géométrie de l‘airlift sur la circulation des fluides mais aussi la rétention gazeuse déterminante en terme de transfert d‘oxygène et capacité de nettoyage des membranes. La viabilité et l'activité respirométrique de boues activée ont alors été étudiées sous différentes conditions opératoires. Les résultats ont montré une évolution semblable des deux paramètres en fonction des conditions imposées. Ceci confirme l‘intérêt de la mesure de viabilité qui peut être conduite en ligne sur le système, à la différence de la mesure par respirométrie qui nécessite une procédure spécifique plus ou moins complexe. Toutefois, les essais ont montré aussi qu‘une concentration en biomasse importante était nécessaire dans le bioréacteur pour que la viabilité soit mesurable. Les résultats ont aussi montré que la viabilité et l'activité augmentent avec la charge organique (Cv). Cette variation était conforme à l'augmentation des matières volatiles en suspension MVS et de la vitesse de consommation d‘oxygène OUR. Lors de diminution de charge organique, la concentration de protéine dans le milieu a changé inversement avec la viabilité de la biomasse. De possibles améliorations de l'instrument de mesure en ligne de la viabilité et de l'activité de boues activées dans les bioréacteurs sont également discutées. Les performances épuratives mesurées ont confirmé la grande capacité épuratoire d‘un BRM, toutefois, travailler à très forte charge engendre une dynamique de colmatage intense qu‘il faut maîtriser. / In this study a novel method was developed to assess the viability of activated sludge present in a biological treatment process and signify its complementarity from respirometric activity. This method allows the distinction between viable vs. dead and inactive vs. active microbial cells in biomass population and can be used for a better and more efficient control of the biological activity especially in MBR systems.For this purposed two airlift oxidation ditch membrane bioreactors (AOXMBR), were designed and constructed. They were equipped with flat sheet, membranes directly immersed in the airlift section where the air injection induced sludge aeration, water circulation and continuous membrane cleaning.To evaluate the relevance of the batch, fed-batch and AOXMBR) were carried out in order to obtain a better understanding of biomass characteristic for MBR performance.Firstly, for determining the treatment capacity of the proposed AOXMBR is important to understanding of the hydrodynamic characteristics of the system. And impact of design parameter on hydrodynamic characterization of the system was investigated. The results showed the gas holdup and liquid velocity increased with increase in superficial gas velocity and decrease in distance from aeration zone. Furthermore, gas holdup and liquid velocity in downcomer section did not show any significant variations with change in the top to bottom clearance ratio. The riser gas holdup data was related to the superficial gas velocity and the top to bottom clearance ratio data. Also, the downcomer gas holdup was related to superficial gas velocity and distance from airlift section.Secondly, viability and respirometric activity of activated sludge under different activated sludge conditions (batch, fed-batch) at high cell density as the model of membrane bioreactors were investigated. The results showed the same downward trend for both these parameters (viability and respirometric activity) which was due to quantitative and qualitative changes in the microbial culture in the activated sludge. Based on different fed of substrate for each experimental run (batch, fed-batch), operational variables showed significant influence in viability and activity of activated sludge. Also, the effect of changing physicochemical condition.on viability and respirometric activity was investigated. The results showed that respirometric activity was affected more strongly by temperature than viability.Thirdly, biological performance of AOXMBR was carried out.Finally, base on data obtained in the last experiment, in this part the capacitance sensor used as the on-line monitoring of viability of activated sludge in AOXMBR. Results showed that viability and activity were increased with organic loading rate (OLR) increasing until 5 kg COD m-3 d-1. This variation was in accordance with increasing of MLSS, MLVSS and OUR. The results also showed that the viability of biomass decreased when reducing the organic loading rate from 5 to 4 kg COD m-3 d-1. Also, protein concentration in system changed inversely with activated sludge viability.The possible reasons are discussed for future improvements online instrument for measuring viability and activity of activated sludge in biological wastewater. Summary of the principal results and novelty of this thesis obtained in this study: The porposed system would reward improved efficiency across the oxidation ditch, airlift and membrane bioreactor. The AXOMBR is a suitable system for operating at high organic laoding rate. However, the suddenly reduction of OLR affects on viability of activated sludge. The specific characterization of the system is capable of working at three different zone: aerobic, anoxic and anaerobic zone. Also, the time of operating at each zone can be changed with superficial gas velocity top to bottom clearance.
455

Rejection and critical flux of calcium sulphate in a ceramic titanium dioxide nanofiltration membrane

Ahmed, Amer Naji January 2013 (has links)
This thesis describes the rejection efficiency and the fouling behaviour of calcium sulphate solutes in a 1 nm tubular ceramic titanium dioxide nanofiltration membrane. Calcium sulphate is considered as one of the greatest scaling potential inorganic salts that responsible for membrane fouling which represents a main challenge in the expansion of membrane processes for desalination of brackish and saline water. The surface charge type and magnitude for the composite amphoteric TiO_2 membrane were characterised using streaming potential measurements. Electrokinetic membrane experiments were conducted in a background electrolyte comprising 0.01 M (NaCl). The zeta potential was estimated from the measured streaming potential using the Helmoholtz-Smoluchowski equation and the surface charge density was subsequently calculated using the Gouy-Chapman and Graham equations. The experimental results showed that the membrane was negatively charged at neutral pH and its iso-electrical point (i.e.p) was at pH of 4.0. The rejection behaviour of calcium sulphate at three different initial concentrations (0.001, 0.005 and 0.01 M) were investigated compared to other naturally occurring minerals (NaCl, Na_2 SO_4, CaCl_2) in single salt solutions. The rejection experiments were conducted at five different applied trans-membrane pressures ranged from 1.0 to 5.0 bars. Salt retention measurements showed that the rejection sequence was R (CaSO_4) > R (Na_2 SO_4) > R (CaCl_2) > R (NaCl). This rejection sequence behaviour showed an inverse relationship with the diffusion coefficients of the four salts. The salt with the lowest diffusion coefficient (CaSO_4) showed the highest rejection (43.3%), whereas that with the highest diffusion coefficient showed the lowest rejection. The rejection of calcium sulphate solution at saturation concentration was also conducted after a suspension solution of 0.015 M (CaSO_4) was prepared and filtered. The ionic analysis for calcium sulphate permeates indicated that, for the negatively charged TiO_2 membrane, the rejection for bivalent anion (SO_4^(2-) ) was higher than that of the bivalent cation (Ca^(2+) ).The critical flux (CF) experiments were carried out at six trans-membrane pressure ranged from 1.0 to 6.0 bars to identify the form and the onset of calcium sulphate fouling (as gypsum) using different concentrations below saturation concentration (0.001, 0.005, 0.01 M) and at saturation concentration. Two different flux-pressure techniques have been applied and compared to determine the critical flux values; these are: step by step technique and standard stepping technique. The obtained critical flux results from both measuring techniques (for all the four sessions) confirmed that the critical flux was reached and exceeded. The present work indicated that the resulting critical flux values from both measuring procedures were decreased as the ionic strengths of the calcium sulphate solutes were increased. A mathematical model has been proposed to identify the key parameters that affect the transport performance inside the TiO_2 nanofiltration membrane. The original Donnan steric pore model (DSPM) was used to simulate the rejection of 0.01 M sodium chloride as a reference solution. The membrane effective pore radius was estimated using two different transport models, both of these models depend on the permeation test of uncharged solute (glucose). The Donnan potential was determined based on the membrane effective fixed charge density which was determined by supposing that the membrane surface charge was uniformly distributed in the void volume of cylindrical pores. The theoretical rejection of NaCl solute for the present DSPM model was found to be in agreement with the experimental data.
456

Vliv zanášení výměníku a součinitel prostupu tepla / Effect of exchanger fouling and heat transfer coefficient

Konopiský, Karel January 2020 (has links)
This diploma thesis covers the influence of fouling in heat exchangers and heat transfer coefficient. In the first part of the thesis are covered the characteristics of fouling and its formation, process, and effects on heat transfer surfaces in exchangers. In the next part of the thesis, chemical analysis of cooling water is performed on an extracted sample and the potential of fouling is determined based on the analysis. In the conclusion part, computational models of fouling in the tube side of the heat exchanger are presented; fouling of an actual heat exchanger is calculated and compared with data captured during the operation of the heat exchanger.
457

Modelování zanášení a jeho vlivu na technicko-ekonomické charakteristiky trubkových zařízení na výměnu tepla v linkách termického zneškodňování odpadů / Modelling of fouling and its influence on technical-economic characteristics of tubular heat transfer equipment in units for thermal processing of wastes

Keliš, Michal January 2008 (has links)
The main subject of this study is the improvement of predicative ability of previously developed mathematical model for prediction of so-called “fouling critical velocity”. Attention is devoted especially to the flue gas side fouling process on active heat transfer surfaces in tubular heat exchange tube banks installed in waste incineration process plants and also a technical – economic analysis based on obtained results. The model improvement consists among others in taking into account another forces (electrostatic, capillary etc.) haven't yet been considered, which influence the mutual contact between flue gas particles in case of sedimentation fouling or the contact between particles and heat exchanger tube walls respectively. The improved model has therefore more predicative ability to the reality of fouling process. The results are used for technical – economic analysis, which determines an optimal heat exchanger design with respect to fouling. Furthermore, the algorithm of this analysis, essential fouling mechanisms, fouled heat exchanger surface cleaning methods as well as fundamental knowledge of fouling coefficient prediction are presented, whereas the emphasis is placed on industrial tubular heat exchange equipment installed in waste incineration process plants.
458

Čištění vzduchotechnických systémů a dosažitelné energetické úspory / Cleaning of ventilation systems and potential energy savings

Lapáček, Milan January 2015 (has links)
The main aim of this thesis is to explore fouling of air ducts and its influence on energy consumption of HVAC systems. The first part focuses on typical parts that create the IAQ in buildings and on evaluating energy consumption of air transportation. The following section deals with the theories of fluid flow, flow regimes and pressure losses that are created as a side effect. The thesis outlines possible methods of assessing the impact of pollution with an emphasis on pressure losses and their influence on the fan power consumption. The actual experimental measurement, conducted in a selected industrial plant, is focused on an influence of cleanness of textile diffuser on HVAC device power consumption. For the further research of this process, measuring equipment with suitable measurement method is designed and constructed.
459

Senzitivní vrstvy pro optické biosenzory a proteinové čipy / Sensitive Layers for Optical Biosensors and Protein Chips

Rodriguez Emmenegger, César January 2012 (has links)
Sensitive layers for optical biosensors and protein chips The goal of this thesis was the development of sensitive surfaces for optical affinity biosensors detecting in complex biological media. The practical application of these surface-based technologies has been hampered by protein fouling from biological media, in particular blood plasma, where the vast majority of relevant analytes are present. The work of the thesis was centred in three main foci:  Design and preparation of antifouling and non-fouling surfaces  Evaluation and conceptualisation of their resistance to fouling from blood plasma and serum as well as other biological fluids  Preparation of sensitive layers for detection in complex biological media Three approaches were used to prepare protein resistance surfaces, i) ω-functional self-assembled monolayers (SAM), ii) end-tethered polymers and iii) polymer brushes prepared by surface initiated controlled radical polymerisation. Investigation of proteins in the blood plasma deposits on PEG- based surfaces revealed that some fouling is unavoidable in PEG-based surface modifications. A novel type of non-fouling polymer brushes based on poly[N-(2-hydroxypropyl) methacrylamide] challenged the accepted ideas for the design of protein resistant surfaces. For the first time a...
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Cílené biokompatibilní nanočástice pro terapii a diagnostiku rakoviny. / Targeted biocompatible nanoparticles for therapy and cancer diagnostics.

Neburková, Jitka January 2018 (has links)
Nanoparticles (NPs) have considerable potential in targeted medicine. NPs can merge various functions and serve as labels for imaging or as nanocarriers in therapy. Modification of NPs with targeting ligands can lead to highly specific interactions with targeted cancer cells. However, the efficacy of targeting depends on the ratio between specific and non-specific interactions of a NP with the cell. Non-specific interactions of NPs are unrelated to targeted receptors and need to be eliminated in order to decrease background noise during imaging and adverse effect of drugs on healthy tissues. In this thesis, surface modifications of NPs were explored mainly on biocompatible carbon NPs called nanodiamonds (NDs), which have exceptional fluorescent properties such as long fluorescence lifetime, no photobleaching and photoblinking and sensitivity of their fluorescence to electric and magnetic field. Main issues addressed in this thesis are low colloidal stability of NDs in buffers and media, their non-specific interactions with proteins and cells and limited approaches for ND surface modifications. These issues were solved by coating NDs with a layer of biocompatible, hydrophilic, and electroneutral poly(ethylene glycol) or poly[N-(2- hydroxypropyl) methacrylamide] polymers. Optimized polymer coating...

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