Ce mémoire traite de la limitation de courant à partir de supraconducteurs HTc. L'utilisation de la transition naturelle d'un état supraconducteur vers un état dissipatif est envisagée pour limiter les courants de défaut sur les réseaux de distribution électrique. Cette application de la supraconductivité est très prometteuse puisque aucune solution conventionnelle ne réalise cette fonctionnalité pour la haute tension. Le gain réalisé par l'installaton de limiteurs de courant serait une densification des réseaux électriques et une amélioration de la qualité de l'énergie distribuée. Cette étude se scinde en deux points. Le premier concerne l'étude expérimentale du comportement de différents matériaux supraconducteurs HTc pour la limitation de courant. Cette caractérisation a été menée en régime nominal alternatif (mesures des pertes) et en régime de défaut. Dans le cadre de cette étude, le matériau YBCO mono domaine a fait l'objet d'une analyse approfondie à haute température. Un travail de modélisation numérique visant à prédire les conséquences d'une transition inhomogène et à estimer les pertes en régime assigné a également été mené. Afin de valider la faisabilité d'un appareillage haute tension, un démonstrateur 1 kV / 100 A constitué de 43 méandres d'YBCO texturé a été testé à une température de 90,5 K. Cette étude s'est également focalisée sur la dynamique de la transition des matériaux supraconducteurs. Nos expériences semblent montrer que la transition est plus homogène au voisinage de Tc. Cette observation est principalement justifiée par la faible valeur de Jc au voisinage de Tc, par des considérations thermiques (meilleure propagation du front de transition) et magnétiques (ancrage magnétique et mécanisme avalancheux de la transition différents près de Tc). Des résultats expérimentaux mettent également le doigt sur l'importance des échanges thermiques latéraux sur la transition des supraconducteurs. L'analyse menée montre que l'énergie dissipée au sein du matériau étudié semble l'être de façon localisée.

Made available in DSpace on 2014-06-11T19:23:00Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-05-17Bitstream added on 2014-06-13T18:08:59Z : No. of bitstreams: 1 manzano_bc_me_rcla.pdf: 1854321 bytes, checksum: 9a0ee7b01dd9ad96a34b4a6c821113b3 (MD5) / Os problemas que mais afetam a qualidade da água de rios e lagos estão associados com os descartes realizados nestes ambientes, principalmente, os de esgotos domésticos e industriais tratados de forma inadequada ou não tratados. Esses efluentes podem conter compostos químicos perigosos pela sua potencialidade em induzir efeitos citotóxicos e genotóxicos à biota exposta. Neste sentido, o presente trabalho teve por objetivo verificar o possível potencial citotóxico, genotóxico e mutagênico de químicos presentes nas águas do ribeirão Tatu, Limeira/SP, provenientes de descartes ilegais de pequenas indústrias e esgotos domésticos por meio do teste de aberrações cromossômicas (ACs) e micronúcleo (MN) em Allium cepa e ensaio do cometa em células de mamíferos. Foram realizadas coletas sazonais em cinco diferentes pontos do ribeirão, entre os anos de 2008 e 2009. As análises físicoquímicas das amostras de água mostraram uma grande degradação na qualidade da água do ribeirão, decorrente dos descartes de esgotos domésticos e industriais, de águas pluviais contaminadas e escoamento da agricultura. Os dados referentes ao bioensaio com A. cepa mostram que os períodos de seca são os mais críticos, pois levaram as respostas mais severas de indução de ACs e de MN no organismo teste utilizado. Em relação ao ensaio do cometa com as células HTC, as amostras de água coletadas no período de chuva intensa, apresentaram maior genotoxicidade, principalmente nos pontos mais impactados pelo recebimento dos efluentes, devido, possivelmente, ao carreamento de contaminantes para o leito do rio, promovido pelo escoamento da água das chuvas / The issues that most affect the water quality of rivers and lakes are associated with discharges in these environments, especially those of domestic and industrial sewage inadequately or not treated. These effluents may contain hazardous chemical compounds for their ability to induce cytotoxic and genotoxic effects to the biota exposed. In this sense, the present study aimed to determine the potential cytotoxic, genotoxic and mutagenic of chemicals present in the waters of the ribeirão Tatu, Limeira / SP, from illegal discharges from small industries and domestic sewage through the test of chromosomal aberrations (CAs) and micronucleus (MN) in Allium cepa and comet assay in mammalian cells. Five seasonally collections were performed at five different places of the river in 2008 and 2009. The physical-chemical analysis of water samples showed a large degradation in water quality of the stream, resulting from discharges of municipal and industrial wastewater, storm water and contaminated runoff from agriculture. The data on A. cepa bioassay show that the droughts are the most critical because the answers led to more severe induction of CAs and MN in the test organism used. Concerning the comet assay with HTC cells, water samples collected during the period of strong rain, had higher genotoxicity, especially at points of most impacted by the receipt of effluents, due possibly to the carrying of contaminants to riverbed, sponsored by runoff from rainfall

Hydrothermal carbonization (HTC) is a process where elevated temperature and pressure is used in order to convert biomass to hydrochar, a coal-like substance with good dewatering properties and many potential uses. HTC can be used to treat digestate from anaerobic digestion, but the process water that remains after the hydrochar has been recovered needs to be treated further in the wastewater treatment plant. In order to make HTC more competitive compared to other sludge treatments it is important to find a good use for the process water. The main objective of this master thesis was to investigate the effects of recirculating HTC process water to the anaerobic digestion. To achieve the objective, both theoretical calculations and experimental trials were performed. The experimental trials were conducted with an Automatic Methane Potential Test System (AMPTS II) in order to investigate the anaerobic digestion in laboratory scale. In the first trial, three substrates, process water, hydrochar, and primary sludge were tested for their biochemical methane potential (BMP). All substrates were mixed with inoculum. Process water had a BMP of 335 ± 10 % NmL/gvs (normalized CH4 production in mL per g added VS (volatile solids)), hydrochar had BMP of 150 ± 5 % NmL/gvs, and primary sludge had a BMP of 343 ± 2 % NmL/gvs. The methane production was almost the same for process water as for primary sludge i.e. no inhibitory effects could be seen when process water was mixed with only inoculum. In the second trial, a more realistic scenario was tested where process water was co-digested with primary sludge at different ratios. The results from the second trial were not statistically reliable and therefore cannot be used on their own to determine with certainty if the process water could have an inhibitory effect in a full-scale anaerobic digester. However, the combined results from both trials indicate that it is unlikely that the process water would have an inhibitory effect. The possible increase in methane yield, if the digestate from a biogas facility was treated in full-scale implementation of the HTC process, was calculated theoretically. The produced process water would have the capacity to increase the methane production with approximately 10 % for a biogas facility. For the calculations, the BMP for process water was assumed to be 335 NmL/gvs and no synergetic effects was considered.

Since the beginning of the 20th century plastic has been a widely used material, which has resulted in large quantities of plastic being produced in the last century. The plastics of today are mainly produced from fossil raw materials, which gives it a high climate impact. Plastic also has a long service life, which creates problems with handling after the new period when new plastic is produced at a faster rate than plastic debris can be recycled or incinerated. One possible approach is to switch from plastic from fossil sources to bioplastics, which is produced by renewable sources. This means a reduction in the environmental impact as the amount of fossil CO2 emissions from combustion of plastics would decrease. Polyhydroxyalkanoates (PHAs) are created by short volatile fatty acids (VFAs) added to bio sludge from a wastewater treatment plant at a pulp and paper mill where there is a lot of bacteria and microorganisms. Some of the bacteria in the sludge have the ability to accumulate PHA when VFA is added in excess and then be able to use it as an energy and carbon source in cases of starvation. This means that PHA produced in this way can be degraded by bacteria making it biodegradable while having similar properties as oil-based plastics. Production of PHA is currently expensive as it is often necessary to purchase VFA for production. To make it economically sustainable to replace oil-based plastics with PHA, the cost of PHA production must therefore be reduced. This can be done by using mixed bacterial cultures from, for example, industrial wastewater treatment plants and by creating their own composition of VFA through fermentation. At the paper mill at BillerudKorsnäs Gruvön there are several process streams that today are led to the water treatment plant, one of which is from PM6 (Paper Machine 6). By fermenting that stream, VFA can be formed with a composition of acetic acid, propionic acid, and butyric acid. The current may thus be suitable to use as a substrate in PHA production. Another way to produce VFA is to ferment the residual flow from hydrothermal carbonation (HTC) of bio sludge. According to (Samorì et al., 2019), acetic acid, butyric acid and valeric acid are formed, which means that even this stream may be suitable as a substrate for PHA production. The purpose of this thesis is to investigate the effects of the composition of VFA on the production of PHA from forest industrial bio sludge. The study covers two different cases, Case PM6 and Case HTC, where two different types of composition of VFA are added to paper sludge from the paper mill. The experiments were performed in cylindrical tanks on three occasions where the first two experiments had a volume of 30 liters and the last experiment a volume of 10 liters. On the first occasion, the maximum accumulation rate in the growth phase was studied. In the second instance, a high accumulation rate was sought, but also survival after the growth phase. The first two trials were batch trials where the sludge was dosed until saturation was achieved. On the third occasion, the possibility of carrying out PHA production with a continuous sludge exchange was studied. The experiments were analyzed by FTIR which provided information on the absorbance of the sludge which shows how the PHA concentration increased during the course of the experiments. Extractions were then performed to obtain the concentration of PHA that eventually accumulated in the sludge. The results show that biomass from BillerudKorsnäs Gruvön's mills accumulated PHA faster with VFA composition from fermented PM6 effluent compared to VFA composition from fermented HTC condensate. Calculations made with input from the experiments indicate that it is possible to produce a larger amount of PHA per year with Case PM6. The conclusion is therefore that Case PM6 is preferable if as large a PHA production as possible wants to be achieved. Case HTC is instead preferred if reduced PHA production can be tolerated in favor of biocarbon production.

Gas turbines are today used in numerous industrial and aeronautical applications. To increase the specific power output and efficiency, a high turbine inlet gas temperature is desired. The high temperature leads to the need of cooling critical components in the hot gas path. Siemens Industrial Turbomachinery AB, SIT AB, in Finspång manufactures gas turbines where the internal cooling of critical components is done through serpentine channels. To utilize the cooling air as efficiently as possible, vortex creating objects are placed inside the channel which result in higher heat transfer. To compute the heat transfer in the channel, correlation based approaches that will give a uniform value for an entire channel are often used. This thesis contains two parts. First, investigating how an automated CAE process can be developed that is able to be incorporated into the SIT AB CAE process of today and with a future vision of a, basically, "one-click-CFD" approach for non-generic geometries. Secondly, how CFD simulations for predicting heat transfer levels inside the cooling channels with high accuracy and that captures local features of heat transfer can be performed. The suggested CAE approach involves the CAD-tool NX for geometry creation and for managing an entire CFD project the ANSYS software Workbench, combined with ANSYS Meshing for generation of computational grid, CFX-pre and CFX for pre-processing and solving and CFD-post for post-processing. This approach is suggested for generic geometries due to the simplicity in incorporating it into existing CAE processes. For the future vision of non-generic geometries, the inhouse developed project manager Concept is suggested. It allows for customized coupling between a broader range of available software tools. To validate the CFX model and to investigate how the CFD calculations should be performed, two cases were set up, one where the CFD model and the inhouse code was compared to experimental data of a generic geometry and one where the CFD model and the inhouse code were compared at engine-like conditions. The results for the experimental case resulted in heat transfer coefficients from the CFD model that were 30% off from experimental data, and the inhouse code maximum deviation was 10%. Compared to previous numerical studies this was considered to be of acceptable accuracy, and the location of data extraction points were considered to cause the deviation in the CFD model. For the engine-like case both CFD and inhouse code predicted the heat transfer level as expected. The simulations were performed in steady state mode on automatically generated meshes with the SST-Reattachment turbulence model. The Reynolds number varied from 10 000 to 80 000 and the meshes were around 4-10M elements in size.

With a growing population but scarce primary phosphorus sources, recycling of the vital element has become an important research area throughout the last decades. Several streams in society are potential resources for recirculation but municipal sewage is considered one of the most available materials. With current technologies in wastewater treatment, over 95 % of the influent phosphorus is captured in the sludge along with a variety of other nutrients. However, due to increasing fractions of pharmaceutical residues and heavy metals also following the sludge, direct use as fertiliser is being phased out in most European countries in favour of extraction methods. Extraction of nutrients from the sludge is problematic mainly because of dewaterability difficulties. Thus, pretreatment of the material is required to access the desired components at a reasonable cost and energy consumption. Hydrothermal carbonisation (HTC) is a technology showing high potential for treatment of wet carbonaceous material without necessity of prior drying. The resulting product is hygenised, essentially free from pharmaceuticals and easily dewatered. In this Master’s thesis principal conditions for release of phosphorus from HTC converted digested sludge under acid leaching have been experimentally investigated. Dependence of time, temperature, dry solids (DS) content of HTC sludge and pH have been studied. Also, differences arising from acid type have been considered by comparing acidulation with sulphuric acid and hydrochloric acid. A short investigation of the recovery of the dissolved phosphorus from leachate by precipitation was also performed where calcium ions were added to both sulphuric and hydrochloric acid leachates. Extraction of phosphorus from HTC converted sludge has shown to be easier than from pure metal phosphates under comparable leaching conditions and pH values. Also, the dissolved phosphorus concentrations obtained in the presence of HTC converted sludge was higher than for theoretical equilibrium concentrations where all phosphorus is in the form of iron(III) or aluminium(III) phosphate. A maximum leachate phosphorus concentration was around 2500 mg/L, recorded in leaching experiments performed at a dry HTC product concentration of 10 % (w/w) in an extraction solution of water acidified with sulphuric acid. Leaching procedures performed at pH values between 2 and 1 with 1 and 5 % DS HTC product resulted in dissolution of 90 % of ingoing phosphorus at an acid charge of 0.5 kg H2SO4/kg DS HTC product. At this chemical charge, release of phosphorus from converted sludge is fast. Similar amounts of dissolved phosphorus were recorded after 15 min as after 16 h retention time. Possibly, time dependence becomes relevant at lower charges. The dissolution of phosphorus is negatively affected by temperature increases at moderate acid loads, and by possibly by hydrochloric acid at pH values below 2. Addition of calcium gave a dissolved phosphorus reduction of 99.9 % in both the sulphuric acid and hydrochloric acid leachates. Gypsum, CaSO4, also precipitates from the sulphuric acid leachate resulting in 67 % more dry mass. Due to high release of metals during acidulation, the precipitate was also contaminated with large fractions of metals in addition to calcium. In summary, this investigation has demonstrated that up to 90 % of the phosphorus content of the HTC converted sludge can be released by acid leaching, and almost 100 % of the phosphorus can be recovered from the leachate by precipitation with calcium ions.

Orientador: Tiago Rodrigues / Dissertação (mestrado) - Universidade Federal do ABC. Programa de Pós-Graduação em Biossistemas, 2012

手機產業是人類發明產品中，成長最快速的產業。近二十年的時間，已銷售超過三十億隻手機。在手機產業成長及利潤趨近成熟飽和之際，智慧型手機的出現，帶給手機業者新的利潤及事業發展空間，但同時也改變了手機產業長久以來的產業生態及營運模式。iPhone 的上市及其結合軟硬體和下載服務的創新營運模式，顛覆了傳統手機市場的思維與操作方式，也讓消費者對於手機上網及應用服務有了不同的體驗與認知。Apple在App Store有超過十萬個應用程式，讓使用者以自行下載自己需求的應用服務。Apple這種爲個人量身打造的個人化行銷，讓iPhone自2007年六月上市以來至今已銷售了四千多萬支，並且讓Apple iPhone 2009年第三季獲利，打敗全球市佔率第一的Nokia，創下手機產業的歷史紀錄。 宏達電在2007年六月搶先在iPhone上市前，搶先推出HTC Touch 觸控智慧型手機，轟動全球，也讓HTC躋身於全球前五大智慧型手機品牌。 HTC自創的HTC Flow使用者介面，不僅打破過去Microsoft WM 的標準介面設計，更奠定HTC在全球智慧型手機的品牌形象及里程碑。在Touch上市之後，HTC 不斷推陳出新，陸續發表了HTC Touch 2， Pro 2等手機，更於2008年10月與Google合作，推出全球第一隻Android手機G1，隨後並推出 HTC Dream、Magic及備受好評的Hero及HTC Sense 使用者介面。在2009年12月更推出全球第一支4.2 吋的Windows Mobile 6.5的手機 HD2，在2010年1月又由Google在CES大展推出宏達電代工生產的第一支Google品牌手機Nexus One，大幅拉抬宏達電的知名度及強化宏達電在Android 手機平台的領先形象。 Google在2007年成立開放手機聯盟(OHA)，把原本封閉的手機作業系統，一舉推向免費授權的系統，把原本在電腦上的服務也盡量複製到手機，推出Google Mobile Service (GMS)，除了HTC，許多手機大廠如Motorola，Samsung，SE，紛紛開始上市Android介面手機且開始經營品牌的加值應用服務，除此之外，還有許多台灣的電腦廠商如華碩、宏碁也紛紛加入Android智慧型手機市場。Google Nexus One於2010年一月上市，Google計畫複製iPhone營運模式的成功經驗，藉由上市Google手機，擴展Android System及應用程式市場的營收，並首度成立全球性的網路商店，宣稱以簡單的概念為核心， 建立一個全新的銷售通路，創造一個簡單的使用者體驗，簡單的購買程式並自由選擇費率方案等服務。 未來的智慧型手機競爭，不僅在於硬軟體的推陳出新，還要思考整體營運模式，把內容服務當成競爭優勢的重點。在這波新的智慧型手機戰役中，iPhone 及HTC是否能夠持續保持優勢？ 本研究將比較Apple iPhone及HTC兩家公司之事業創新營運模式及核心策略並探討Apple iPhone 及 HTC在未來手機產業中將會面臨的挑戰。

L'apparition des supraconducteurs à Haute Température Critique en 1986 puis leur développement permet maintenant leur utilisation en électrotechnique. Il devient important de connaître précisément leur comportement électromagnétique et notamment leurs pertes. Pour cela, un modèle numérique (éléments finis) a été implanté dans FLUX3D. Les supraconducteurs y sont représentés comme étant parfaitement amagnétiques et régis par une loi en puissance entre le champ électrique et la densité de courant. Cette loi est pour l'instant indépendante de l'induction magnétique. Nous avons été amenés à étudier et comparer différentes formulations (A,3A/3t,fo,TT0O,Âcouplée avec les équations de circuit) permettant d'imposer un champ magnétique extérieur, un courant voire d'inclure un supraconducteur dans un circuit électrique. Le modèle numérique a ensuite été utilisé pour des études quantitatives d'une part, puis qualitatives d'autre part. Une étude détaillée, en champ propre, sur un fil OPIT de Bi-2223 a été menée numériquement, analytiquement et expérimentalement. Ceci a permis de valider l'hypothèse du couplage entre les filaments et a également été l'occasion de comprendre la méthode électrique de mesure de pertes. Le cas d'une bobine possédant deux couches de fils supraconducteurs a ensuite été étudiée. Un modèle analytique de calcul des pertes pour une bobine possédant n couches a alors été développé. Toutes les études de ce mémoire ont également permis de mieux cerner le domaine de validité du modèle de Bean. Les limites d'une loi en puissance avec un courant critique indépendant de l'induction et de la température sont également apparues.

La découverte des supraconducteurs à Haute Température Critique en 1986 relance l'intérêt porté à la supraconductivité. Ces matériaux sont arrivés à un stade où leur utilisation dans des dispositifs électrotechniques est envisageable. Néanmoins, il est primordial de connaître leurs pertes AC précisément pour dimensionner correctement les dispositifs. C'est pourquoi nous avons étudié dans un premier temps ces pertes AC dans un supraconducteur. Un modèle analytique applicable à une géométrie cylindrique (bobinages) a été ainsi développé et comparé à un modèle numérique. Nous avons réalisé des mesures expérimentales afin de comparer ces différents modèles. Dans le cadre du projet Européen READY, un transformateur supraconducteur monophasé HTC de 41 kVA a été entièrement dimensionné sur les plans électromagnétiques, thermiques et mécaniques. Ce transformateur, entièrement froid, pourra fonctionner dans l'azote liquide jusque vers 65 K ou l'hélium gazeux pour atteindre des températures inférieures. H sera refroidi par un tube puisé. De nombreuses expériences ont été faites pour valider nos choix et nous apporter certaines données expérimentales indispensables comme les pertes fer à froid où la résistance thermique de contact. Enfin, une étude très préliminaire sur différents transformateurs supraconducteurs d'une puissance de 30 MVA a permis de montrer l'intérêt de la technologie supraconductrice sur ces dispositifs.