Recent studies have shown that ruthenium(III) acetylacetonate is acting as homogeneous catalyst in the hydrolysis of sodium borohydride. Although trimethlyphosphite is found to be a poison for the catalytic hydrolysis of sodium borohydride, a longer observation of the reaction in the presence of ruthenium(III) acetylacetonate and 2 equivalent trimethylphosphite shows an unexpected enhancement in the catalytic activity after an induction period. The same rate enhancement is observed when 2 equivalent triphenylphosphine is added into the reaction solution. Addition of 1 equivalent 1,2-bis(diphenylphosphino)ethane, dppe, into the solution shows similarly a rate enhancement in the hydrolysis of sodium borohydride catalyzed by ruthenium(III) acetylacetonate. The effect of 1,2-bis(diphenylphosphino)ethane on the catalytic activity of ruthenium(III) acetylacetonate in the hydrolysis of sodium borohydride was studied by varying mole ratio of dppe / Ru(acac)3, ruthenium concentration, substrate concentration and temperature. The highest enhancement in the rate of hydrolysis was obtained when 1 equivalent dppe was used and therefore, this mole ratio of dppe / Ru(acac)3 was used in the further studies. The rate of the reaction was found to be first order in catalyst concentration and zero order in substrate concentration. From the evaluation of rate constant versus temperature data, the activation parameters for the hydrolysis of sodium borohydride catalyzed by ruthenium(III) acetylacetonate plus 1 equivalent dppe were found to be Ea= 59 &plusmn / 2 kJ/mol, &amp / #8710 / H&amp / #8800 / = 60 &plusmn / 1 kJ.mol-1 and &amp / #8710 / S&amp / #8800 / = -50 &plusmn / 3 J.(mol.K)-1. A series of control experiments were performed to characterize the active catalyst. However, the only useful information could be obtained by comparison of the UV-vis electronic absorption spectra taken from the solution during the catalytic reaction, is that, ruthenium(III) is reduced to ruthenium(II) in the course of reaction. It was concluded that a ruthenium(II) species is formed as a transient and may be the active catalyst in the reaction. After the reaction, the only ruthenium species isolated from the solution was the ruthenium(III) acetylacetonate.

Thermal mismatch between different components of a system could be sources of problems like residual stress induced cracking, thermal fatigue or even optical misalignment in certain high technology applications. Use of materials with tailored thermal expansion coefficient is a counter-measure to overcome such problems. With its negative thermal expansion coefficient zirconium tungstate (ZrW2O8) is a candidate component to be used in synthesis of composites with controlled thermal expansion coefficient (CTE). ZrW2O8 is typically produced by solid-state reaction between zirconium oxide and tungsten oxide at 1200oC. However, it has been demonstrated that ZrW2O8 can also be synthesized using wet chemical techniques, which provide a superior chemical homogeneity that often extents down to the atomic scale, and the convenient means of controlling nucleation and growth of the primary crystallites. With the commonly adopted wet chemical approaches, it is possible to crystallize particles with sizes in the submicrometer range at temperatures as low as 600 oC or even lower. In these studies, precursors are aged either below 100 oC (7 days &ndash / 3 weeks), or at 160-180 oC under hydrothermal conditions (1&ndash / 2 days). Besides the obvious disadvantage in the ageing steps, use of tungsten sources with high cost in all approaches, constitutes the other disadvantage. Production of composites with tunable controlled thermal expansion (CTE) has been achieved by blending negatively and positively expanding materials in different proportions. In majority of these studies composites have been produced by conventional sintering methods. Spark Plasma Sintering (SPS) is a recent technique / in which sintering can be achieved at relatively low temperatures in short durations. There is only one study made by Kanamori and coworkers on the use of SPS in sintering of a composite, in which ZrW2O8 is one of the constituents [1]. This study aims the synthesis of ZrW2O8 particles and composites that possess tunable or zero CTE. A novel precursor recipe for ZrW2O8 synthesis was developed. In preparation of the precursor a total of 2 days of ageing and a temperature less than 100 oC was used. It was developed using a cost-effective tungsten source, namely tungstic acid and its final pH was lower than 1. The particles obtained from &lsquo / unwashed&rsquo / procedure had sizes in micrometer range, while those obtained from &lsquo / washed&rsquo / case had sizes in the range of 400-600 nm. These precursors could readily be crystallized at 600 oC, which in turn provided the desired particle sizes for composite applications. Experimental details on the precursor development are hereby presented with a discussion on the effects of solution parameters (i.e. solubility of tungstic acid, adjustment of the stoichiometry, ageing time) on the phase purity of the fired product. Zirconium oxide (ZrO2) has positive vi thermal expansion, therefore ZrW2O8/ZrO2 was selected as the composite system, and for their synthesis both conventional and spark plasma sintering methods were experimented. Composition ranges that provide composites with almost zero CTE&rsquo / s were determined. The composite having a composition of containing 35% ZrW2O8, 65% ZrO2, and 35 w/o Al2O3 and sintered at 1200 oC for 24 hours had an expansion coefficient of 0.20 x 10-6/K for conventional method, while the one having a composition of 55% ZrW2O8, 45% ZrO2 and sintered at 1000 oC for 5 minutes had an expansion coefficient of 0.94 x 10-6/K for spark plasma sintering method. For characterization of the products X-ray diffraction (XRD), scanning electron microscopy (SEM), photon correlation spectroscopy (PCS), and thermal and dilatometer analyses (DTA/TGA/DMA) were used.

The aim of this thesis is to examine the practices directed to the flexibilisation of the labor brought together with the means of neoliberal structuring and the trade union crisis appeared as an outcome of these in terms of the Tekel Workers&rsquo / resistance in Ankara. The theoretical frame of this study is created in the content of the discussions that starting from the Marxist approach on trade unions and the critical view within this approach focus on the reasons of the crisis of the trade unions as a result of the applications of the neoliberal ideological structuring that appeared by the crisis of the accumulated capital during the mid-70&rsquo / s. Over this perspective, the analysis concentrates on the one hand employment models&rdquo / being multi-layered and insecure and on the other, the fragmentation of the class and therefore the representation crisis of the trade unions that are the outcomes of the commodification of the labor by the deregulation, privatization and flexibilisation policies applied in the process of neoliberal hegemony. In this context, the resistance of the Tekel workers that continued non-stop for 78 days is argued basing on the assumption that the process which forces the more flexible, insecure working conditions without any attachment to the trade unions via the application of the neoliberal political apparatuses becomes the common platform/destiny of all the parts of society constituted by different identity structures.

Lanthanum orthoborate (LaBO3) has aroused interest of scientists for many decades because of their remarkable properties and potential applications. They provide favorable magnetic properties for various applications. Additionally, they possess high VUV transparency and exceptional optical damage when they compose with rare earth elements. This study comprises the synthesis of pure lanthanum orthoborate, europium, dysprosium and terbium doped lanthanum orthoborate by two methods with v three fuels, citric acid, glycine and urea. LaBO3 has already been synthesized by various methods, however / in this work, two alternative roads are suggested, microwave assisted method and sol-gel microwave assisted method. The second task of the work is to find out the best luminescent product by altering the synthesis conditions, type of the doping material and the doping amount of the rare earth element. For the microwave assisted combustion method, urea was used as a fuel. After synthesis in the microwave oven, further heating up to 950&deg / C was performed. For the microwave assisted sol-gel method, citric acid and glycine were used. After obtaining the gel mixture, the product is synthesized in the microwave oven at 1200 W for ten minutes. For this route, again 950&deg / C heating for 2 hours was performed. Powder X-ray diffraction method was employed for the characterization of the material. The morphological properties of doped and un-doped materials were studied by SEM (Scanning Electron Microscope) and TEM (Transmission Electron Microscope). Besides, FT-IR (Fourier Transform Infra red) spectrometry analyses were performed to detect the differences in the bond structure and also to identify the corresponding bands. Luminescence studies were performed to detect the best emission intensities by using Fluorescence spectroscopy. The XRD patterns confirmed that lanthanum orthoborate production was successful by three precursors. The space group is Pnma, and the crystal system is orthorhombic with the unit cell dimensions / a= 5.8761(1)

No description available.

In this thesis, solid state reactions of Ln2O3, Y2O3, B2O3 and (NH4)2HPO4 were investigated to synthesize LnBP2O8 (Ln= Dy, Ho, Er) and YBP2O8 type of borophosphates which were not reported before. The products were analyzed by XRD, IR, DTA, SEM and EDX methods. In the first part of this thesis, synthesis of YBP2O8 through the solid state reaction of Y2O3 + 4(NH4)2HPO4 + B2O3 have been studied in the range 800-1140 &deg / C. Orthophosphates of Dysprosium, Holmium, Erbium and Yttrium have tetragonal xenotime (YPO4) or zircon (ZrSiO4) structure. Examination of X-ray powder diffraction data at 1140 &ordm / C showed that the obtained structure was xenotime type together with weak BPO4 and Y(PO3)3 lines. The formula was calculated as YBxP1+xO4+4x through EDX and XRD data. The pattern was indexed in tetragonal system with the unit cell parameters of a= 6.8863, c= 6.016 &Aring / and s.g. is I41/amd. In the second part of this research, synthesis of LnBP2O8 through the solid state reaction of Ln2O3 + 4(NH4)2HPO4 + B2O3 (Ln= Dy, Ho, Er) have been studied in the range 800-1200 &ordm / C. At 1200 &ordm / C DyBP2O8 was obtained with tetragonal structure with the unit cell parameters of a= 6.905, c= 6.051 &Aring / and s.g. I41/amd. Using the same procedure HoBP2O8 was obtained at 1100-1200 &ordm / C and the XRD pattern was indexed in tetragonal system with the unit cell parameters of a= 6.887, c= 6.024 &Aring / and s.g. I41/amd. In the structural analysis of ErBP2O8 obtained by the same reaction, the system was found as tetragonal and was indexed with a= 6.849, c= 5.998 &Aring / and s.g. I41/amd. Examination of the unit cell parameters with respect to ionic radius showed that the unit cell parameters decrease depending on the lanthanide contraction. The structures of the compounds obtained throughout this thesis were examined by IR spectroscopy and relation between the spectra and IR vibrational modes were established. The presence of bands due to BO4 in the final products revealed that Boron is in the solid solution with the tentative formula YBxP1+xO4+4x for Y and LnBP2O8 for lanthanides.

Cette thèse cherche à mettre en évidence les raisons qui ont amené une large part des ateliers grecs à orientaliser leurs productions durant la "période orientalisante" (VIIe siècle avant J.-C.). La méthode déployée pour répondre à cet objectif consiste en une contextualisation sociale des artisanats orientalisants, laquelle s'effectue par le biais de l'analyse d'un certain nombre de contextes archéologiques et de textes. Une fois le rôle des objets orientalisants dans la société proto-archaïque mis en évidence, leurs raisons d'être apparaissent plus clairement.<p>Le développement de la citoyenneté en Grèce à partir de la seconde moitié du VIIIe siècle avant J.-C. a donné lieu à une extension du pouvoir politique et militaire à une part plus importante de la population des cités. La propagation de ce qui constituait autrefois les principaux modes de reconnaissance a amené les élites à développer de nouvelles façons de se distinguer dans le paysage social. Dans un même temps, les citoyens de chaque cité ont développé des institutions communales, telles que les cultes civiques et les repas en commun, afin d'unifier le groupe qu'ils formaient et de renforcer le fossé qui séparait celui-ci du reste de la société. Le travail de contextualisation entrepris dans cette thèse a montré que l'art orientalisant constituait un outil facilitant la mise en place de ces deux évolutions.<p>D'une part, parce qu'ils faisaient explicitement allusion aux cultures du Proche-Orient, dont les richesses exerçaient une réelle fascination sur les Grecs de cette époque, les objets orientalisants permettaient de rehausser le prestige de leurs propriétaires. Autrement dit, ils constituaient des modes de reconnaissance sociale particulièrement efficaces. De nombreuses données archéologiques et textuelles ont permis de confirmer ce point de vue, mettant en évidence que les objets orientalisants étaient utilisés lors de banquets prestigieux, comme offrandes ostentatoires aux dieux et aux morts, ou encore pour contenir de précieux parfums. <p>D'autre part, en tant qu'esthétique nouvelle, complètement libérée des formes géométriques utilisées durant les siècles précédents, l'art orientalisant figurait également au rang des pratiques censées unifier la citoyenneté. Cette seconde conclusion a été mise en évidence au travers de l'étude du cas de la Crète, où, au VIIe siècle, l'art orientalisant a en grande partie été utilisé dans le cadre d'institutions civiques :les banquets publics, les cultes civiques, et les guerres.<p><p><p><p>This dissertation aims at the understanding of the reasons lying behind the orientalization of artefacts in Greece during the so-called "Orientalizing period" (i.e. the 7th cent. BC). In order to achieve this goal, the author focused on archaeological contexts and textual information. They allowed him to replace the orientalizing objects back in their original social context and to understand their initial purposes. <p>The birth of the citizenship in Greece at the end of the 8th cent. BC gave rise to the extension of the political and military power to a wider part of the population. This created a need for the former elite to develop other means of social distinction. Conversely, the communities of citizens developed communal institutions, like civic cults, communal dinners, etc. meant to cement and to level the group, and to reinforce the gulf that separated it from the rest of the society. This thesis showed that orientalizing art contributed to the setting up of these changes. <p>On one hand, because Greek orientalizing artefacts explicitly alluded to Near Eastern cultures, that were indeed perceived as being particularly rich at that time by the Greeks, they could enhance the individual prestige of the people using them. Archaeological research confirmed this hypothesis, showing that Greek orientalizing objects were used during conspicuous banquets, as lavish offerings for the dead and the gods, and for containing precious perfumes. <p>On the other hand, as artefacts decorated in a new style, completely freed from the geometric aesthetics displayed in the previous centuries, orientalizing objects also figured among the practices developed for strengthening the citizens’ corps. This second conclusion was reached through the study-case of Crete, where orientalizing art of the 7th cent. seems nearly exclusively used in a context of civic institutions :public banquets, civic cults and festivals, and wars.<p><p> / Doctorat en Histoire, art et archéologie / info:eu-repo/semantics/nonPublished

El documento presenta la ELABORACIÓN DEL EXPEDIENTE TÉCNICO DEL PUENTE PALO BLANCO, DISTRITO DE HUARMACA, PROVINCIA DE HUANCABAMBA, DEPARTAMENTO DE PIURA, 2018. El tramo de la ubicación del puente es afectado gradualmente por el Río Palo Blanco, el cual ha aumentado su caudal debido a la activación de las quebradas, impidiendo así la comunicación de los caseríos aledaños al C. P. Palo Blanco, Distrito de Olmos. En el año 2017, el Perú presenció devastadores fenómenos naturales a causa del fenómeno El niño, el cual destruyó cuatro mil kilómetros de caminos rurales, 4,391 kilómetros de carreteras y 489 puentes quedaron destruidos en todo el país [1]. M.T.C. adoptó como prioridad la construcción de puentes modulares en la sierra de Piura, el plan de acción se denominó “Reconstrucción con cambios”. Por esta razón, y dentro del marco de proyección social de USAT, se propone este trabajo. Se realizó los estudios preliminares. Del estudio de topografía, mecánica de suelos e hidrología se analizó la mejor ubicación y longitud de 42 m conformado por 2 vigas de acero de alma llena y una losa de concreto con 4.5 m de ancho, del estudio de transito e hidráulica se propuso el diseño del Puente tipo compuesto con vigas de acero y losa de concreto. Finalmente el proyecto tiene un presupuesto de 2 751 741.84 soles.

Ce mémoire traite des Celtes qui migrèrent en Grèce et après un revers devant les portes de Delphes, s’installèrent en Asie Mineure sous le nom de Galates et créèrent ainsi la Galatie. Les Galates sont connus pour leur rôle de mercenaires dans les armées hellénistiques, mais aussi pour leurs raids conduits sur les cités côtières d’Asie Mineure. Les sources littéraires, épigraphiques et archéologiques nous témoignent des relations entre les citoyens grecs et les Galates. Les Grecs les décrivaient comme des bêtes sauvages et cette image s’est imprégnée dans les écrits modernes d’aujourd’hui. L’examen des sources permet de comprendre d’où vient cette haine des Galates, mais aussi de nuancer les propos émis par les Grecs de l’Antiquité. Le rôle de l’historien est de préserver une pensée objective et de ne pas laisser les émotions dicter son texte. Plusieurs savants modernes tombent dans le piège de parler des Galates négativement en se servant des expressions comme « la menace galate » ou bien « le danger galate ». Cette recherche conscientise le lecteur à s’interroger sur l’utilisation des termes à choisir lorsque l’on traite de différents peuples. Pour finir, les méthodes des Galates et des défenses grecques sont analysées afin de clore le portrait des Galates à l’époque hellénistique.

In this thesis, firstly, carbon-supported platinum nanoparticle catalysts have been prepared by using PtCl4 and H2PtCl6 as starting materials and 1-hexanethiol, and tert-octanethiol, as surfactants for the first time. Secondly, these prepared catalysts were heated to 200 &deg / C, 300 &deg / C, and 400 &deg / C for 4 h under argon gas. Lastly, PtRu/C catalysts, which have different atomic percent ratios of Pt and Ru (Pt/Ru: 0.8, 2.1 and 3.5), were prepared using PtCl4 and RuCl3 as starting materials and tert-octanethiol as a surfactant. Each was characterized by X-ray diffraction, transmission electron microscopy, energy dispersive analysis, X-ray photoelectron spectroscopy, cyclic voltammetry, and elemental analysis, and their activities were determined toward the methanol oxidation reaction. It has been found that all prepared catalysts are more active toward methanol oxidation reaction compared to the commercial catalysts. It was also found that increasing the temperature during the heat treatment process results in an enlargement of platinum particle size and a decrease in catalytic activity in the methanol oxidation reaction. Transmission electron microscopy shows that platinum nanoparticles are homogeneously dispersed on the carbon support and exhibited a narrow size distribution with an average particle size of about 2-3 nm in diameter. X-ray photoelectron spectra of all catalysts indicated that most of the platinum nanoparticles (&gt / 70 %) have an oxidation state of zero and rest (&lt / 30 %) have a +4 oxidation state with (Pt 4f7/2) binding energies of 71.2-72.2 and 74.3-75.5 eV, respectively.