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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Critical Elements Recovery from Acid Mine Drainage

Li, Qi 13 February 2024 (has links)
The rapid development of advanced technologies has led to an increase in demand for critical elements that are essential in the manufacturing of high-tech products. Among these critical elements, manganese (Mn), cobalt (Co), and nickel (Ni) are used in the production of batteries, electronics, and other advanced applications. The demand for these elements has been growing exponentially in recent years, driven by the rise of electric vehicles, renewable energy, and other emerging technologies. However, the United States is heavily dependent on foreign sources of critical minerals and on foreign supply chains, resulting in the potential for strategic vulnerabilities to both economy and military. To address this problem and reduce the Nation's vulnerability to disruptions in the supply of critical minerals, it is important to develop critical minerals recycling technologies. A systematic study was conducted to develop a process for producing high-purity Mn, Co, and Ni products from an acid mine drainage (AMD). As major contaminants, Fe and Al in the solution were sequentially precipitated and eliminated by elevating the pH. After that, a pre-concentrated slurry containing Mn, Co, Ni, and Zn was obtained by collecting the precipitates formed in the pH range of 6.50 to 10.00. The pre-concentrated slurry was redissolved for further purification. Sodium sulfide was added into the redissolved solution to precipitate Co, Ni, and Zn selectively while retaining Mn in the solution. Almost 100% of Co, Ni, and Zn but only around 15% of Mn were precipitated using a sulfur-to-metal molar ratio of 1 at pH 4.00. The sulfide precipitate was calcined and then completely dissolved. The critical elements existing in the dissolved solution were efficiently separated using a two-stage solvent extraction process. Ultimately, Co and Ni products with almost 94% and 100% purity were obtained by sulfide and alkaline precipitation, respectively. AMD also contains rare earth elements (REEs), which can be recovered through selective chemical precipitation. REE removal improved at pH 4.0 after converting ferrous to ferric ions with H2O2. Aluminum species in the solution hindered REE adsorption on ferric precipitates, and ferrous ions reduced REE adsorption on aluminum precipitates at lower pH, but at higher pH, REE removal increased due to ferrous ion precipitation. Various tests and analyses were conducted to understand the partitioning mechanisms of REE during the precipitation process of AMD. Sulfide precipitation is crucial to separate Mn from other elements, but the presence of contaminants like Fe and Al can affect sulfide precipitation efficiency. The effects of Al3+ iii and Fe2+ on the precipitation characteristics of four valuable metals, including Mn2+, Ni2+, Co2+, and Zn2+, were investigated by conducting solution chemistry calculations, sulfide precipitation tests, and mineralogy characterizations. It was found that the ability of the valuable metals to form sulfide precipitates followed an order of Zn2+ > Ni2+ > Co2+ > Mn2+. The sulfide precipitate of Zn2+ was the most stable and did not re-dissolve under the acidic condition (pH 4.00 ± 0.05). In addition, the sulfide precipitation of Zn2+ was barely affected by the contaminant metal ions. However, in the presence of Al3+, the precipitation recoveries of Mn2+, Ni2+, and Co2+ in a solution containing all the valuable metals were noticeably reduced due to simultaneous hydrolysis and competitive adsorption. The precipitation recoveries of Ni2+ and Co2+ in solutions containing individual valuable metals also reduced when Fe2+ was present, primarily due to competitive precipitation. However, the recovery of Mn2+ was enhanced due to the formation of ferrous sulfide precipitate, providing abundant active adsorption sites for Mn species. In the solution containing all the valuable metals, Fe2+ promoted the recoveries of the valuable metals due to the higher concentration of Na2S and the formation of ferrous sulfide precipitate. / Doctor of Philosophy / The rapid development of advanced technologies has increased the demand for critical elements essential in manufacturing high-tech products. In this study, a process was developed for producing high-purity Mn, Co, and Ni products from an acid mine drainage (AMD). A product with around 30 wt.% Mn was produced. Co and Ni products with 94% and 100% purity were also obtained. However, when developing the process, it was found that a portion of the REEs is often lost to the precipitates of the dominant metal contaminant ions (Fe and Al) in the staged precipitation. It was found that the REE removal increase was realized through adsorption onto the surfaces of the ferric precipitates. In sulfide precipitation, the presence of Fe and Al in the solution can significantly influence the separation efficiency of the critical elements. The effect of Al3+ on the sulfide precipitation is due to the simultaneous hydrolysis of aluminum and sulfur ions. The reduction of the recovery of valuable metals caused by the Fe2+ is due to the form of iron sulfides.
2

Elementos de integração do planejamento estratégico: um estudo no IFPE, com foco nas ações do Campus Afogados da Ingazeira.

CÂNDIDO, José Leandro. 06 September 2018 (has links)
Submitted by Maria Medeiros (maria.dilva1@ufcg.edu.br) on 2018-09-06T13:44:10Z No. of bitstreams: 1 JOSÉ LEANDRO CÂNDIDO - DISSERTAÇÃO (PROFIAP-CCJS) 2016.pdf: 1422568 bytes, checksum: 265a55c75ae59eabdd98a9d5b3277e72 (MD5) / Made available in DSpace on 2018-09-06T13:44:10Z (GMT). No. of bitstreams: 1 JOSÉ LEANDRO CÂNDIDO - DISSERTAÇÃO (PROFIAP-CCJS) 2016.pdf: 1422568 bytes, checksum: 265a55c75ae59eabdd98a9d5b3277e72 (MD5) Previous issue date: 2016-08-29 / O planejamento estratégico está sendo adotado por instituições públicas, de maneira muito bem sucedida. Nas Instituições de Ensino Superior (IES), o Plano de Desenvolvimento Institucional (PDI) tem-se consolidado como instrumento de planejamento estratégico, porém, muitas vezes, representa apenas o cumprimento de uma formalidade institucional, sem maiores preocupações com os benefícios que pode proporcionar, quando adotado como instrumento de gestão. Neste contexto, o presente trabalho concentra-se em analisar o planejamento estratégico no âmbito das Instituições de Ensino Superior, buscando identificar elementos críticos para sua integração com as ações realizadas. Por meio de estudo de caso, observou-se a influência dos elementos críticos para a integração entre o planejamento estratégico institucional do IFPE, e as ações realizadas no âmbito do Campus Afogados da Ingazeira. Para a compreensão do fenômeno no âmbito das IES, recorreu-se à pesquisa bibliográfica como ferramenta útil para explorar o conhecimento científico existente acerca do tema e analisar quais elementos são considerados relevantes no processo de implementação do plano. Quando se abordou a esfera institucional do IFPE, utilizou-se das pesquisas documental e de campo, por meio da análise do PDI, do Plano de Ação do Campus Afogados da Ingazeira e da aplicação de entrevistas semiestruturadas, para assimilar a relação das ações do dia a dia com os instrumentos de planejamento. Após a análise dos elementos críticos e sua relação com a integração das ações do Campus Afogados da Ingazeira ao planejamento estratégico da Instituição, os principais resultados da pesquisa apontam que o planejamento estratégico ainda não é efetivamente utilizado como instrumento de gestão de maneira sistemática. Os responsáveis pela execução das ações que atingiriam os objetivos nele determinados não percebem a presença do planejamento como um legítimo norteador das ações cotidianas. A proposta de ação, para iniciar o ciclo de aperfeiçoamento contínuo de integração entre o planejamento estratégico e as ações regulares, concentra-se em torno do envolvimento da gestão ao adotar o planejamento estratégico como instrumento de gestão; designação de líderes para facilitar o processo de elaboração, acompanhamento e avaliação do plano com a articulação de Reitoria e Campi, e promoção do planejamento participativo. As demais soluções surgiriam em consequência destas ações, à medida que o processo fosse sendo aperfeiçoado pelos novos ciclos de aprendizagem, promovidos pelo seu acompanhamento e revisão. / Strategic planning is being adopted by public institutions in a very successful way. In Higher Education Institutions (IES), the Institutional Development Plan (PDI) has been consolidated as a strategic planning tool, however, often it is worked out just for the fulfillment of an institutional formality, with no major concerns with the benefits it can provide when adopted as a management tool. In this context, this paper focuses on analyzing the strategic planning in the context of Higher Education Institutions to identify critical elements for its integration with the actions which are taken. Through case study, it was observed the influence of the critical elements for the integration between the IFPE's Institutional Strategic Planning, and the actions carried out under the Campus Afogados da Ingazeira. To understand the phenomenon within the IES, it was used the literature as a useful tool to explore the existing scientific knowledge on the subject and to analyze which elements are considered relevant in terms of the implementation process. When it approached the institutional sphere of IFPE, we used the documentary and field research, by analyzing the PDI, the Campus Afogados da Ingazeira's Action Plan and application of semi-structured interviews to assimilate the ratio of day by day shares with the planning tools. After the analysis of the critical elements and its relation to the integration of Campus Afogados da Ingazeira's shares with the strategic planning of the institution, the main results of the research show that strategic planning is not effectively used as systematically management tool. The responsible for the implementation of actions that would achieve the objectives it determined not realize the presence of planning as a legitimate guiding of daily actions. The proposed action to start the continuous improvement cycle of integration between the strategic planning and regular actions, focuses around the involvement of management to adopt strategic planning as a management tool; designation of leaders to facilitate the process of developing, monitoring and evaluation plan with the articulation of Rectory and Campi, and promoting participatory planning. The other solutions would arise as a result of these actions, as the process was being improved by new cycles of learning promoted by its monitoring and review.
3

Critical elements scavenged by secondary gypsum and HFO : Determined by sequential extraction combined with mineralogical studies

Flodin, Emma January 2022 (has links)
The demand for metals is great for the purpose of developing green technologies, and EU has listed 30 metals and minerals that are of critical importance for the maintenance and evolving of today’s society, so called critical materials. However, mining of raw materials generates mine waste which can have adverse effect on human health, ecosystems, and surrounding areas. To be able to prevent the release of toxic levels of elements from mine waste, an understanding of how different elements behave in the secondary environments is necessary in order to use the most successful methods for mining remediation. It is common that secondary minerals, such as gypsum and/or HFOs (hydrous ferric oxides), forms in mine waste or in downstream environments, depending on the geochemical conditions. From prior studies, it is well established that trace elements are sorbed by HFO. But studies are scares regarding co-precipitation of elements with secondary gypsum formation, and few studies investigates the possibility of critical elements to be captured by secondary minerals. In this study, a prior unknown white precipitation along with tailings material from the Smaltjärnen tailings beach in Yxsjöberg, Sweden, has been investigated by combining mineralogical studies (SEM-EDS and DXRD analysis) with sequential extraction. The aim with the study was to identify the precipitation and to examine if critical elements had co-precipitated with the precipitation and HFOs within the sample. From the results it was possible to prove that the white precipitation was gypsum (CaSO4*2H2O), and it was indicated that some of the critical elements (beryllium for instance) showed affinity for gypsum, and that bismuth, tungsten, and chromium were sorped by HFOs. The combining of chemical analysis with mineralogical studies was of great importance for determining in which mineral phases the leached elements were situated, and the study has shown that secondary gypsum formation can be an important sink for some critical elements. More studies should be performed within this field of research to further investigate the importance of secondary minerals for scavenging of elements, not only to prevent toxic levels to be leached, but also to capture these elements in the purpose of re-mining. / Idag är behovet av metaller stort inom användningsområden för att utveckla gröna teknologier. EU har därför listat 30 metaller och mineral (kritiska material) som anses vara kritiska för att underhålla och utveckla dagens samhälle. Men brytning av råmaterial resulterar i generering av gruvavfall där avfallet potentiellt kan utgöra en risk för att skada bland annat människors hälsa och ekosystem. För att kunna förhindra att giftiga halter av grundämnen släpps ut från gruvavfall så krävs en förståelse om hur olika ämnen beter sig i sekundära miljöer, för att på så sätt kunna tillämpa de mest framgångsrika metoderna för sanering och återställning av gruvområden. Det är vanligt förekommande att sekundära mineraler (såsom gips och järnhydroxider) fälls ut i gruvavfallet och/eller nedströms om gruvområdet beroende på de geokemiska förhållandena. Tidigare studier har visat att spårämnen kan binda till järnhydroxider, men endast ett fåtal studier undersöker samutfällning av olika spårämnen tillsammans med sekundärt gips. Hur specifikt kritiska metaller kan fångas upp av sekundära mineral är ännu inte välstuderat. I denna studie har en vit, tidigare okänd, utfällning provtagits från en av deponierna med anrikningssand i den historiska volframgruvan i Yxsjöberg. Utfällningen identifierades genom att kombinera mineralogiska studier (SEM-EDS och DXRD analys) med kemiska lakvattenanalyser från en sekventiell lakning. Målet med studien var att mineralogiskt karaktärisera den okända utfällningen och att undersöka om kritiska ämnen möjligen samutfällts tillsammans med de sekundära mineralen. Studien visade att utfällningen var sekundärt gips (CaSO4*2H2O) och det kunde påvisas att vissa kritiska metaller visade affinitet för gipset (exempelvis beryllium) och att andra kritiska metaller samutfällts/adsorberats av järnhydroxider. Att kombinera dom olika metoderna visade sig att vara till stor nytta för att kunna påvisa vilka mineral dom olika grundämnena var bundna till, och studien har även visat att sekundärt gips kan vara en sänka för vissa kritiska metaller. Mer studier bör utföras inom detta forskningsområde i framtiden för att vidare undersöka hur sekundära mineral kan binda kritiska metaller, inte endast för att förhindra att giftiga halter av metaller släpps ut, utan också för att undersöka möjligheten att återvinna gruvavfallet för utvinning av kritiska metaller.
4

Compositional Systematics of Sphalerites from Western Bergslagen, Sweden / Huvud-och spårelementsystematik i zinkblände från västra Bergslagen, Sverige

Kritikos, Aristeidis January 2016 (has links)
Sphalerite is, apart from being the main global source of zinc (Zn), also one of the main source for the critical elements indium (In), gallium (Ga) and germanium (Ge), which can be extracted as by-products during Zn mining. In the westernmost part of the Palaeoproterozoic Bergslagen ore province, Sweden, In-anomalies have been reported from sulphide mineralizations. These In-anomalies can be attributed to either pre-ore formation crustal processes manifested by the local (Svecofennian, c. 1.87-1.89 Ga) syn-volcanic mineralisations, or to epigenetic metasomatic events primarily related to younger (c. 1.80-1.79 Ga) granitoids. In this study, sphalerite samples from 19 different mineralisations in westernmost Bergslagen were examined by both electron probe microanalyzer (EPMA) and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), in order to firstly, measure trace element concentrations, and especially those of the critical element In, Ga and Ge, and secondly, to apply this information to gain new information on the trace element inventory and incorporation mechanisms of sphalerite. The dataset also allows for testing the ore-formation process models, not least in cases of elevated In-contents. Utilization of these two analytical methods also provided the opportunity for a direct spot-to-spot comparison of their performance in detecting trace element concentrations in sphalerite. The results verify the In-enrichment of the area, whereas Ga and Ge only follow crustal abundancies. The concentrations of the other trace elements vary significantly, even at a sample scale. The compositional variation shows several patterns between certain elements, suggesting that their incorporation in the sphalerite lattice was allowed via substitution mechanisms (e.g. In3++(Cu+,Ag+)↔2Zn2+; Fe2++Cd2++Mn2+↔3Zn2+; Cu++Mn2++In3+↔3Zn2+). In contrast, some measured high Cd, Ag and Pb concentrations are attributed to nano (or micro) inclusions of primarily galena. Other elements such as As, Sn, Sb, Se, Au, Tl, Ni, Te and Mo yielded, in almost all the samples, concentrations below the detection limit for both analytical methods. Discrimination methods based on trace element concentrations and distribution of the In-enriched mineralizations suggest that the In-anomalies are most likely related to Svecofennian volcanic to subvolcanic hydrothermal processes, forming mineralisations that were later modified during the Svecokarelian orogeny. Finally, the direct comparison of EPMA results to that of LA-ICP-MS, showed the significantly better performance of the latter method in detecting trace-level concentrations, provided that a proper calibration procedure has been followed. / Sulfidmineralet zinkblände är, förutom att vara den huvudsakliga globala källan för zink (Zn), också ett av de viktigaste värdmineralen för de kritiska metallerna indium (In), gallium (Ga) och germanium (Ge), vilka kan utvinnas som viktiga biprodukter vid zinkbrytning. I den västligaste delen av malmprovinsen Bergslagen i Mellansverige har In-anomalier rapporterats från flera mineraliseringar. Dessa lokala In-anrikningar kan tillskrivas antingen processer verksamma innan och under den vulkaniska aktiviteten, eller senare geologiska händelser relaterade till yngre graniter. I denna studie har zinkblände från 19 olika mineraliseringar i västra Bergslagen karakteriserats med två olika system för mikrokemisk analys; elektronmikrosond (EPMA) och laserablativ induktivt kopplad plasma-masspektrometri (LA-ICP-MS). Detta har gjorts för att mäta spårelementhalter, och särskilt då för de kritiska metallerna In, Ga och Ge. Genom att använda dessa två metoder parallellt gavs också möjligheten till direkta jämförelser mellan dem vad gäller deras kapacitet för spårelementanalys av zinkblände. Resultaten verifierar att detta område är anomalt In-anrikat, medan halterna av Ga och Ge är låga och endast följer genomsnittshalterna för kontinental jordskorpa. Halterna av de övriga spårelementen varierar avsevärt, även på individuell provskala, och visar i flera fall systematiska mönster mellan vissa element. Dessa mönster tyder på att deras införlivande i zinkbländestrukturen gått via flera specifika utbytes-(substitutions-)mekanismer (t.ex. In3++ (Cu+, Ag+) ↔2Zn2+; Fe2+ + Cd2++ Mn2+ ↔3Zn2+, Cu++ Mn2++ In3+ ↔3Zn2+). Däremot kan förhöjda halter av Cd, Ag och Pd tillskrivas nano- (eller mikro-) inneslutningar av framförallt blyglans. Andra element, som As, Sn, Sb, Se, Au, TI, Ni, Te och Mo uppvisade halter under detektionsgränserna för båda analysmetoderna i nästan alla undersökta prov. Bildningsmässiga (genetiska) diskrimineringsmetoder baserade på spårelementhalter kombinerat med de geologiska och spatiella relationerna för de In-anrikade mineraliseringarna tyder på att de senare bildades genom svekofenniska vulkanisk-hydrotermala processer och därefter modifierats under svekokarelsk bergskedjebildning. Slutligen, i den direkta jämförelsen av EPMA gentemot LA-ICP-MS, visade den senare metoden signifikant bättre kapacitet för spårämnesanalys, förutsatt att ett korrekt kalibreringsprotokoll har följts.
5

'n Ondersoek na kritiese elemente van 'n prakties-teologiese teorie vir kinderbediening

Yates, Hannelie 11 1900 (has links)
Summaries in Afrikaans and English / The research for this study has shown that the circumstances in which the majority of children in South Africa find themselves, are extremely complex and problematic, to such an extent that not only the quality of children's lives is endangered, but their lives as such. Besides the measures taken by government to improve the situation of children, it is pre-eminently the Christian church that is able to render a unique and, at the same time, a fully relevant contribution to the debate, processes and actions regarding children in South Africa. For this to be achieved, however, the church should be guided by a theology that is truly contextual and missionary in nature. In this study, therefore, distinct critical elements are being identified, which could be utilized in shaping a theory for child ministry. What is visualized by the researcher in this regard, is the formulation of a practicail-theological theory that is derived from a Scripturally sound theology, on the one hand, and, on the other, oriented to the contextual realities of children. / Die navorsing vir hierdie studie het getoon dat die lewensomstandighede van die meerderheid kinders in Suid-Afrika uiters kompleks en problematies is, in so 'n mate dat nie alleen die lewenskwaliteit van kinders nie, maar hulle lewe selfbedreig word. Benewens die maatreels van owerheidswee om die lot van kinders te verbeter, is dit by uitstek die Christelike kerk wat in staat is om 'n unieke en tegelyk volledig relevante bydrae te lewer tot die debat, prosesse en aksies rakende kinders in Suid-Afrika. Hierin sal die kerk hom egter moet laat lei deur 'n teologie wat op kontekstueel en missioner verantwoorde wyse beoefen word. In die studie word daarom bepaalde kritiese elemente geifdentifiseer wat in verdere teorievorming oor kinderbediening aangewend kan word. Wat in die verband die navorser voor oe staan, is die formulering van 'n prakties-teologiese teorie wat enersyds aan 'n Skrifgetroue teologie ontleen en andersyds aan die kontekstuele realiteite van kinders georienteer is. / Social Work / M. Diac. (Youth work)
6

'n Ondersoek na kritiese elemente van 'n prakties-teologiese teorie vir kinderbediening

Yates, Hannelie 11 1900 (has links)
Summaries in Afrikaans and English / The research for this study has shown that the circumstances in which the majority of children in South Africa find themselves, are extremely complex and problematic, to such an extent that not only the quality of children's lives is endangered, but their lives as such. Besides the measures taken by government to improve the situation of children, it is pre-eminently the Christian church that is able to render a unique and, at the same time, a fully relevant contribution to the debate, processes and actions regarding children in South Africa. For this to be achieved, however, the church should be guided by a theology that is truly contextual and missionary in nature. In this study, therefore, distinct critical elements are being identified, which could be utilized in shaping a theory for child ministry. What is visualized by the researcher in this regard, is the formulation of a practicail-theological theory that is derived from a Scripturally sound theology, on the one hand, and, on the other, oriented to the contextual realities of children. / Die navorsing vir hierdie studie het getoon dat die lewensomstandighede van die meerderheid kinders in Suid-Afrika uiters kompleks en problematies is, in so 'n mate dat nie alleen die lewenskwaliteit van kinders nie, maar hulle lewe selfbedreig word. Benewens die maatreels van owerheidswee om die lot van kinders te verbeter, is dit by uitstek die Christelike kerk wat in staat is om 'n unieke en tegelyk volledig relevante bydrae te lewer tot die debat, prosesse en aksies rakende kinders in Suid-Afrika. Hierin sal die kerk hom egter moet laat lei deur 'n teologie wat op kontekstueel en missioner verantwoorde wyse beoefen word. In die studie word daarom bepaalde kritiese elemente geifdentifiseer wat in verdere teorievorming oor kinderbediening aangewend kan word. Wat in die verband die navorser voor oe staan, is die formulering van 'n prakties-teologiese teorie wat enersyds aan 'n Skrifgetroue teologie ontleen en andersyds aan die kontekstuele realiteite van kinders georienteer is. / Social Work / M. Diac. (Youth work)
7

Extending the security perimeter through a web of trust: the impact of GPS technology on location-based authentication techniques

Adeka, Muhammad I., Shepherd, Simon J., Abd-Alhameed, Raed January 2013 (has links)
No / Security is a function of the trust that is associated with the active variables in a system. Thus, the human factor being the most critical element in security systems, the security perimeter could be defined in relation to the human trust level. Trust level could be measured via positive identification of the person/device on the other side of the interaction medium, using various authentication schemes; location-based being one of the latest. As for the location-based services, the identity of a customer remains hazy as long as his location is unknown; he virtually remains a ghost in the air, with implications on trust. This paper reviews the various location-based authentication techniques with a focus on the role that GPS could play in optimising this authentication approach. It advocates the urgent need to make all transmission devices GPS-compliant as a way forward, despite the privacy issues that might arise.
8

Résultats de généricité pour des réseaux / Generic results for networks

Percie du Sert, Maxime 03 July 2014 (has links)
Un réseau de cellules est un graphe orienté dont chaque sommet (aussi appelé cellule) représente un ensemble de variables et dont les arcs symbolisent les interactions entre ces variables. Les réseaux de cellules jouent un rôle important dans la modélisation de phénomènes neurologiques, de systèmes économiques ou biologiques, etc.. Soit G un graphe orienté possédant N sommets, on dit qu'une application f=(f_1,...,f_N) de X=X_1×...×X_N dans X (où X_j=R^dj) est admissible, si pour tout sommet j, f_j(x) dépend de x_i seulement si i->j est un arc de G. Dans cette thèse nous montrons que si G est fortement connecté et auto-dépendant, génériquement par rapport à f appartenant à l'ensemble des applications admissibles de classe C¹, le système dynamique engendré par l'équation différentielle x'(t)=f(x(t)) vérifie la propriété de Kupka-Smale, c'est-à-dire tous les éléments critiques (points d'équilibre et orbites périodiques) sont hyperboliques et les variétés stable et instable des éléments critiques s'intersectent transversalement. Ainsi, pour un ensemble dense d'applications admissibles, le système dynamique est au moins localement stable par perturbation (admissible ou non). Nous considérons également l'ensemble des applications « dissipatives » f de classe C¹ dont la différentielle Df(x) est une matrice de Jacobi cyclique positive en tout point x. De telles applications définissent un système coopératif. Nous montrons que le système dynamique engendré par l'équation x'(t)=f(x(t)) vérifie génériquement la propriété de Morse-Smale par rapport à de telles applications f, c'est-à-dire le système vérifie la propriété de Kupka-Smale, les éléments critiques sont en nombre fini et l'ensemble des points non-errants est égal à l'ensemble des éléments critiques. Cette propriété entraîne la stabilité structurelle du système dynamique. Finalement, dans cette thèse nous étudions aussi des réseaux de cellules satisfaisant des contraintes de symétrie locale. Pour de tels systèmes, nous montrons tout d'abord des résultats génériques d'observation à symétrie près, de synchronisation et de décalage de phase. Nous utilisons ces résultats pour montrer la généricité de l'hyperbolicité des points d'équilibre ainsi qu'un lemme d'injectivité pour les trajectoires. Les résultats de généricité de cette thèse sont obtenus à l'aide de théorèmes de transversalité de type Sard-Smale. / A coupled cell network consists in a directed graph, with each node (also called cell) representing a set of variables and with each arrow representing the interaction between these variables. Coupled cell networks play an important role in the modeling of phenomena in neurology, economics or biology, etc.. Let G be a directed graph with N nodes. A mapping f=(f_1,...,f_N) of X=X_1×...×X_N to X (where X_j=R^dj) is admissible, if for each node j, f_j(x) depends on x_i only if i->j is an arrow of G. In this thesis, we show that if the graph G is strongly connected and self-dependant, generically with respect to f in the class of admissible C¹-functions, the dynamical system generated by the differential equation x'(t)=f(x(t)) satisfies the Kupka-Smale property, that is all the critical elements (i.e. the equilibria and periodic orbits) are hyperbolic and the stable and unstable manifolds of these critical elements intersect transversally. As a consequence, for a dense set of admissible functions, the dynamical system is locally stable with respect of small perturbations (admissible or not). We also consider the set of "dissipative" mappings f of class C¹, the differential Df (x) of which is a positive cyclic Jacobi matrix at any point x. Such maps define a cooperative system. We show that the dynamical system generated by the equation x'(t)=f(x(t)) is generically Morse-Smale with respect to such mappings f, that is the system is Kupka-Smale, the critical elements are in finite number and the non-wandering set is equal to the set of critical elements. This property implies the structural stability of the dynamical system. Finally, in this thesis we also study coupled cell networks satisfying local symmetry constraints. For such systems, we first show generic results of observation, synchronization and phase shift. We use these properties to show the genericity of hyperbolicity of equilibrium points and an injectivity lemma for trajectories. In the proof of these genericity results, we use different Sard-Smale type theorems.
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Návrh diagnostické soustavy pro malý dopravní letoun / Design of Diagnostic System for Small Transport Aircraft

Harasim, Tomáš January 2015 (has links)
Due to the airliners and aircraft operators pressure on reducing the operating costs, the diagnostic systems are included in aircraft, so that the wearness of single functional elements of other functional systems can be monitored. This monitoring can save money, that are usually spent on maintenance and especially, it leads to an increase of the overall safety of aircraft operations. The task of this work is to design a diagnostic system for small transport aircraft. For the right and proper design, is the correct understanding of the functions of each part on aircraft systems needed. The part of this work is attended to the selection procedure of appropriate diagnostic parameters, next section deals with the suitable options of their scanning. I do mention the summary of the chosen diagnostic parameters for the scanning and the recomended ways of their measuring.

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