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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.
121

Elaboration de nouveaux complexes de cuivre(I) à propriétés électroniques originales

Moudam, Omar 06 July 2007 (has links) (PDF)
La chimie de coordination de complexes cuivreux du type [Cu(PP)(NN)]+ (PP : ligand bisphosphine et NN : ligand phénanthroline) a été étudiée. La stabilité des complexes hétéroleptiques dépend de la nature du ligand PP. Des complexes hétéroleptiques stables et fortement luminescents ont été obtenus en utilisant le ligand POP (bis[2-diphénylphosphinophényl]éther). Lors de la préparation de cette première famille de complexes cuivreux, nous avons découvert fortuitement qu'il était aussi possible d'obtenir des complexes de type [Cu(PP)2][BF4]. Cette nouvelle famille de composés possède des propriétés de luminescence remarquable qui ont été exploitées pour l'élaboration de diodes électroluminescentes. Finalement, nous nous sommes également intéressés à l'élaboration de matériaux donneur-accepteur en associant les fullerènes avec nos complexes du Cu(I).
122

Aspects géométriques des principes locaux-globaux dans la théorie abstraite des formes quadratiques

Kebbab, Eric Franck Idir 20 February 2014 (has links) (PDF)
Les espaces d'ordres abstraits sont introduits par M. Marshall dans les années 70, dans la perspective d'offrir un cadre abstrait à l'étude des formes quadratiques. Vers le début des années 90, les travaux de M. Dickmann, L. de Lima et de F. Miraglia, ont donné naissance à la version duale des groupes spéciaux. Le premier thème que nous traiterons est la caractérisation des points d'un espace d'ordres du corps de fonctions d'une variété réelle, nous reprendrons un résultat de Brumfiel affirmant l'existence d'une correspondance entre ces ordres et des ultrafiltres de semi-algébriques. Nous appliquerons ceci au corps R(x,y). Suivra la caractérisation des ordres de ce corps à travers la notion de demi-branche de Bézout. Le second thème traite des principes locaux-globaux généralisés (ou Conjecture pp). Le premier résultat de la thèse porte sur la séparation des constructibles et sur la principalité des basiques. Nous montrerons que le langage des groupes spéciaux nous offre une vision claire du fait que ces principes découlent trivialement du principe de l'isotropie étendu. Le second résultat traite des contre-exemples à la conjecture dans le cas de la conique rationnelle donnée par l'équation x2+y2=3. Le dernier résultat (le plus important), aborde la conjecture pp dans le cadre du corps R(x,y). Nous nous intéresserons à des familles de polynômes vérifiant certaines conditions géométriques et montrerons que toute formule pp, ayant ses paramètres dans cette famille, vérifie un principe local-global. Nous les baptiserons formules V-universelles. Nous clorons le dernier chapitre par deux méthodes de construction.
123

Adsorption Isotherm Parameter Estimation in Nonlinear Liquid Chromatography

Forssén, Patrik January 2005 (has links)
This thesis concerns the development and validation of methods for the industrially important area of adsorption isotherm parameter estimation in preparative, nonlinear high performance liquid chromatography (HPLC). Preparative chromatography is a powerful separation method to get pure compounds from more or less complex liquid mixtures, e.g., mixtures of mirror-image molecules. Computer simulations can be used to optimize preparative chromatography, but then competitive adsorption isotherm parameters are usually required. Here two methods to estimate adsorption isotherm parameters are treated: (i) the perturbation peak (PP) method and (ii) the inverse method (IM). A new theory for the PP method was derived and led to a new injection technique which was validated experimentally. This injection technique solved the severe problem with vanishing peaks and enabled us to use the PP method to estimate binary competitive adsorption isotherms valid over a broad concentration range. Also, the injection technique made it possible to estimate competitive adsorption isotherms for a quaternary mixture for the first time. Finally, an interesting perturbation peak phenomenon, known as the “Helfferich Paradox”, was experimentally verified for the first time. The IM is a relatively new method to determine adsorption isotherm parameters. It has the advantage of requiring very small samples, but also requires an advanced computer algorithm. An improved implementation of this computer algorithm was developed and tested experimentally. Also, a variant of the IM called “the inverse method on plateaus” was tested experimentally and the estimated adsorption isotherm parameters were shown to be valid over a broader concentration range than those estimated with the standard IM.
124

Aspects géométriques des principes locaux-globaux dans la théorie abstraite des formes quadratiques / Geometric aspects of local-global principle in the abstract theory of quadratic forms.

Kebbab, Eric Franck Idir 20 February 2014 (has links)
Les espaces d'ordres abstraits sont introduits par M. Marshall dans les années 70, dans la perspective d'offrir un cadre abstrait à l'étude des formes quadratiques. Vers le début des années 90, les travaux de M. Dickmann, L. de Lima et de F. Miraglia, ont donné naissance à la version duale des groupes spéciaux. Le premier thème que nous traiterons est la caractérisation des points d'un espace d'ordres du corps de fonctions d'une variété réelle, nous reprendrons un résultat de Brumfiel affirmant l'existence d'une correspondance entre ces ordres et des ultrafiltres de semi-algébriques. Nous appliquerons ceci au corps R(x,y). Suivra la caractérisation des ordres de ce corps à travers la notion de demi-branche de Bézout. Le second thème traite des principes locaux-globaux généralisés (ou Conjecture pp). Le premier résultat de la thèse porte sur la séparation des constructibles et sur la principalité des basiques. Nous montrerons que le langage des groupes spéciaux nous offre une vision claire du fait que ces principes découlent trivialement du principe de l'isotropie étendu. Le second résultat traite des contre-exemples à la conjecture dans le cas de la conique rationnelle donnée par l'équation x2+y2=3. Le dernier résultat (le plus important), aborde la conjecture pp dans le cadre du corps R(x,y). Nous nous intéresserons à des familles de polynômes vérifiant certaines conditions géométriques et montrerons que toute formule pp, ayant ses paramètres dans cette famille, vérifie un principe local-global. Nous les baptiserons formules V-universelles. Nous clorons le dernier chapitre par deux méthodes de construction. / Spaces of orderings were introduced in the last of 70s by M. Marshall, in order to provide an abstract framework to the study of a generalized theory of quadratic forms. In the 90s, the work of M. Dickmann , joined by his student L. Lima and his collaborator F. Miraglia , gave rise to the dual version of this theory, the special groups. First, we focus on the characterization of points of a space of orderings in special the case of function fields of real varieties, we review a Brumfiel?s result proving the existence of a one-to-one correspondence between points of such a space and some family of ultrafilters of semi-algebraic sets of the variety. We apply this to the case where the field is R(x,y). Another characterization uses the concept of Bezout?s half-branch. The second topic deals with a generalized local-global principle, known as the pp-conjecture. The first new result of this thesis focuses on the separation of constructibles and the principality of basics. We show that the first order language traduces well these properties and offers a clear vision that they derive trivially from extended isotropy theorem. The second result presents a generalized counter-example to the pp-conjecture in the case of the rational conic defined by the equation x2 + y2 = 3. The last result (most important), addresses the pp-conjecture in the context of the space of orderings of the field R(x,y). We will focus on families of polynomials satisfying certain geometric conditions and show that any pp-formula, with its parameters in this family, verifies a local-global principle. We baptize them V-universal formulas. We close the last chapter by two construction methods.
125

Cílená příprava kompozitu na bázi PP + anorganické mikro resp. nano anorganické plnivo s různou adhezní mezivrstvou. / Targeted Preparation of Composite Based on PP with Inorganic Micro-, or Nanofiller with Different Adhesive Interlayer

Dombková, Julie January 2012 (has links)
The diploma thesis studies composite of PP and filler particle. As a particle filler was used commercially available CaCO3 (SOCAL 31). The submitted thesis had a goal to find new approaches and technologies of filler surface treatment in order to improve properties of composite materials. The plasma discharge behind static pressure was used for the surface treatment of the fillers. These fillers were afterwards analyzed by using of sedimentation analysis, turbidimetry, infra-red spectroscopy (FT-IR), X-ray diffraction analysis (XRD), scan electron microscopy (SEM), transmission electron microscopy and particle size distribution by laser diffraction. The composites with various volume parts of the fillers were prepared in PIB and studied by short-time tests. Furthermore, the influence of an adhesive layer on fracture mechanical properties of prepared composite was study. Regarding to experimental demand, there was not possible to realize long-term mechanical properties.
126

Evaluation of using bioplastics for lab consumables

Mäepea Nilsson, Lovisa, Gunnarsson, Emelie, Mardini, Sara, Nuur Yusuf, Fartun, Nyström, Jesper January 2022 (has links)
The use of plastic has increased markedly in recent years which has led to more fossil fuels being used and more plastic in nature. This is a literature study that researches on how bio- based plastics can be used instead of plastics made from fossil fuels. The report is written in collaboration with Biotage, which is a global impact tech company that wants to use plastic parts that are made of more sustainable plastic for their products. Relevant and contemporary literature is reviewed, and several alternatives are addressed. The mechanical and physical properties of the different plastics are compared. Laboratory tests are performed on bio-based polyethylene, poly (lactic acid), bio-based polypropylene, polypropylene that contains wood fibre, recycled polypropylene and fossil-based polypropylene that is currently used by Biotage. The properties and way of manufacturing the plastics is discussed according to environmental aspects, as well as cost and recycling. This leads to the result that different plastics can be used for the different parts but plastics produced from bioethanol or biomass would be a more sustainable choice than plastic from fossil fuel.
127

Scapegoating and VOX: Twitter and Right-Wing Rhetoric in Spain

Chiappone, Benjamin 23 August 2022 (has links)
No description available.
128

Skin Health Monitoring Sensor on Textiles : Incorporation of pH Responsive Dyes on Polyethylene and Polypropylene Nonwovens

Biswas, Tuser January 2016 (has links)
Incontinence diapers or disposable absorbent pads provide essential help to people having such a physical difficulty. However, during prolonged used of these products in daily life, the skin inside pad area may get fragile and damaged which are difficult to recover in old ages. Therefore a skin friendly sensor can be added to the inner layer of pad that would monitor the skin condition and signal any abnormalities to the wearer. Smart materials which can change color upon variation of skin pH were incorporated with synthetic nonwoven layers of the pad. Among various incorporation methods of these materials, ‘sol-gel’ coating technique was found to be successfulfor applications on optical sensor and on fewother fabric types. Thus ‘sol-gel’ method with modified recipe for different dye and chemical combinations were experimented in this project.Several developed samples showed color change (e.g. yellow to red) that can be easily detected by wearers’ eyes.Additionally, the methods and materials involved showed no adverse effect on health and environment. Thus this study succeeds to provide with a mean for skin health monitor based on nonwoven textiles by incorporation of color changing materials.
129

Recycling of PVC and XLPE for High Impact Resistance in Spool Development

Granowski, Gregory A 05 1900 (has links)
My work focuses on taking waste wire-grade PVC = poly(vinyl chloride) and waste XLPE = cross-linked polyethylene and recycle them into small wire/cable spool technology in order to reduce waste cost and reduce cost of spool production. The PVC and XLPE were provided by Encore Wire Corp. of McKinney, TX; they have also defined the standard to which I am comparing my results. The end goal is to incorporate as much PVC and XLPE into the spools while maintaining material toughness, impact resistance, as well as cost-effectiveness in the implementation of the waste materials. The work has been divided into two primary sections, the first is focused on improving material strength through the addition of ceramic fillers. The second section is focused on adding PVC and XLPE into a stronger and highly cohesive polymer matrix and optimizing the concentration of the waste products. Since XLPE is non-polar while PVC is strongly polar, compatibilizers such as CPE (chlorinated polyethylene) and MA-DCP (maleic anhydride with dicumyl peroxide) were used to improve interactions between polar and non-polar constituents. Testing involved the tensile mechanical properties, tribology and thermal properties, namely dynamic mechanical analysis (DMA) and evaluation of thermal degradation by thermogravimetric analysis (TGA). Combining PVC and XLPE together is not economically feasible with current compatiblizers. At the same time, introduction of PVC waste or XLPE waste with sufficient properties of the resulting composites is doable.
130

Structure-Property Relationships in Some Novel Polyolefins

Dias, Peter Simon 17 June 2008 (has links)
No description available.

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