Thermo-Calc software AB develops high quality thermodynamic and kinetic databases to predict and simulate accurately multi-component phase behaviour in complex systems. One problem with their Ni-based alloys and superalloy solutions database (TCNI8) is poor description of tungsten partitioning for multi-component nickel based alloys. This work investigates the thermodynamic description of some lower-order systems i.e., Ni-W, Al-Ni-W and Cr-Ni-W by performing key experiments on three binary Ni-W alloys, and two ternary alloys (Al-Ni-W and Cr-Ni-W). Experiments at four different temperatures were carried out in which alloys were homogenized, equilibrated, quenched and investigated to determine the equilibrium solid/liquid compositions. Experimental results are used to validate the thermodynamic descriptions of the liquid and the fcc phase. Unlike ternary Al-Ni-W and Cr-Ni-W, binary Ni-W reproduced the experimental information in a satisfactory way. Ternary parameters for fcc are changed to fit the experimental results of this work. The findings of this work highlight that ternary parameters for the fcc of Al-Ni-W and Cr-Ni-W systems significantly effect the tungsten partitioning values in higher order systems. / Thermo-Calc Software AB utvecklar termodynamiska och kinetiska databaser av hög kvalitet för att korrekt kunna förutsäga och simulera jämvikter och fasomvandlingar i komplexa flerkomponentsystem. Ett problem med deras databas för Ni-baslegeringar och superlegeringar (TCNI8) är att beskrivning av volframpartitionering stämmer dåligt för nickelbaslegeringar. I detta arbete undersöktes den termodynamiska beskrivningen av vissa lägre system, dvs Ni-W, Al-Ni-W och Cr-Ni-W genom att utföra nyckelförsök på tre binära Ni-W-legeringar och två ternära legeringar (Al-Ni-W och Cr-Ni-W). Experimentvid fyra temperaturer utfördes i vilka legeringarna homogeniserades,jämviktsbehandlades, släcktes och undersöktes för att bestämma sammansättning för jämvikt fast fas/smälta. De erhållna experimentella resultaten användes för att validera den termodynamiska beskrivningen av smältan och fcc-fasen. Till skillnad från ternära Al-Ni-W ochCr-Ni-W, reproducerade den experimentella informationen den binära Ni-W-beskrivningen tillfredsställande. Ternära parametrar för fcc justerades efter de experimentella resultaten från detta arbete. Resultaten visar att de ternära parametrarna för fcc i Al-Ni-W och Cr-Ni-W systemen signifikant påverkar volframs fördelning mellan fast fas och smälta i nickelbaslegeringar.

Published Article / Health effects associated with Ni-Cu mining on learners living within the mining area at Selebi Phikwe were investigated through the administration of questionnaires. Results depicted learners suffering from a wide range of different symptoms and illnesses. 70% of the learners complained of coughs, 77% had influenza / common cold, and 80% had headaches. The repeated coughing, constant influenza / common cold and persistent headaches from which learners suffered, were very significantly higher than those at the control site; and incidences of their occurrence increased with closeness to the mining area. The unusual high occurrences of these ailments and illnesses coupled with associated diseases among learners were attributed to several environmental factors including contaminated particulate air matter (PAM) (rich in sulphur and heavy metals) linked to the mining and smelting of Ni-Cu.

This thesis work concerns about the importance of the cast surfaces, surface phenomenon such as the formation of the oscillation marks and exudation and related defects including cracks and segregation that happened during the continuous casting. All of the investigated materials were collected during the plant trials while an in-depth analysis on these materials was performed at the laboratory scale with certain explanations supported by the schematic and theoretical models. The work consists on different material classes such as steels and phosphor bronzes with a focus on the surface defects and their improvements. In order to facilitate the theoretical analysis which could be capable of explaining the suggested phenomenon in the thesis, a reduced model is developed which required lesser computational resources with lesser convergence problems. / <p>QC 20160527</p> / Oscilation mark formation during continous casting of steel

The series of compounds [M(H2O)2(15-crown-5)](NO3)2, M = Mg, Mn, Co, Cu and Zn, has been extended to include two new phases for M = Fe and two new phases for M = Ni. The system [M(H2O)2(15-crown-5)](NO3)2 is remarkable for having many high-Z’ phases (Z’ > 1) with similar packing and for having solid-solid phase transitions through which there is no significant loss of crystallinity. The synthesis of the analogous Ni complex was carried out. Single-crystal X-ray diffraction showed that the coordination of the Ni2+ ion is different from that of the other six M2+ ions in the system [M(H2O)2(15-crown- 5)](NO3)2. High temperature phases with high Z’ (8) were isolated for M = Mg, Fe and Zn. The refinements of such phases are challenging because of the lack of information in the diffraction patterns. Full details of the refinements for these three phases are discussed. Six other Ni(II) complexes consisting of Ni2+, NO3-, 15-crown-5 and different solvents were found when efforts were made to synthesize the compound [Ni(H2O)2(15-crown- 5)](NO3)2. In these chemically different environments, the Ni2+ ions are not coordinated by the 15-crown-5 molecules; rather, one-dimensional H-bonded chains are formed from uncomplexed 15-crown-5 molecules and the Ni(II) complexes. Among these six Ni(II) complexes, the compounds [Ni(H2O)6](NO3)2·(15-crown-5)·H2O, [Ni(H2O)6](NO3)2·(15-crown-5)·2H2O and [Ni(H2O)2(MeCN)(NO3)2]·(15-crown- 5)·MeCN were found to have reversible solid-solid phase transitions between structurally related phases. In all of these transitions, no significant crystal damage was detectable. The two latter systems are unusual because their phase sequences include three transitions and four phases between 90 and 295 K and because of the existence of high-Z’ phases. These high-Z’ phases are best depicted as being intermediate to low- and hightemperature phases. A method based on thermal analyses and X-ray diffraction has been developed for studying such sets of phase transitions.

As demands for alternative sources of energy increase over the coming decades, water electrolysis will play a larger role in meeting our needs. The oxygen evolution reaction (OER) component of water electrolysis suffers from slow kinetics. An efficient, inexpensive, alternative electrocatalyst is needed. We present here high-activity, low onset potential, stable catalyst materials for OER based on a hierarchical network architecture consisting of Fe and Ni coated on carbon fiber paper (CFP). Several compositions of Fe-Ni electrodes were grown on CFP using a hydrothermal method, which produced an interconnected nanosheet network morphology. The materials were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). Electrochemical performance of the catalyst was examined by cyclic voltammetry (CV) and linear sweep voltammetry (LSV). The best electrodes showed favorable activity (23 mA/cm², 60 mA/mg), onset potential (1.42 V vs. RHE), and cyclability. / text

This thesis deals primarily with the eastern Islamic world during the period 1000-40. It attempts to delineate the structure of the Ghaznavid empire, its personal and administrative aspect (Part I) and its military aspect (Part II). The material used in Part II has already appeared in substantially similar form as "Ghaznevid military organisation" in Der Islam, XXXVI, 1960, 37-77. Against this background, the province of Khurasan under Ghaznavid rule, and in particular, the city of Nishapur, are described (Part III). The irruption of the Seljuqs is treated in Part V. However, a survey of what is known of the Oghuz before these migrations is prefixed to this (Part IV). It summarises presently-held views, attempting to synthesise the work of Central Asian specialists, Turcologists, historians and archaeologists, who alone are competent to investigate at first hand this difficult subject. The scope of the thesis is therefore that of the decline of Ghaznavid power in the west, and it is this aspect which has been concentrated upon, for the early years of the Great Seljuq dynasty have already been extensively covered by such scholars as Cl. Cahen, I. Kafesoğlu and M.A. Köymen, and the administrative system of the Seljuqs has been examined by A.K.S. Lambton in her London University thesis on Seljuq institutions. This thesis has been prepared under the joint supervision of the Rev. Dr. W. Montgomery Watt and Mr. J.R. Walsh, to whom I am greatly indebted for help and encouragement; from the latter, in particular, I have enjoyed much stimulating conversation and judicious guidance through the literature of the period.

A supply of clean, carbon neutral and sustainable energy is the most scientific and technical challenge that humanity is facing in the 21st century. Though there is enough fossil fuels available for a few centuries, their use would increase the level of CO2 in the atmosphere. This would lead to global warming and may pose serious threats such as rising of sea level, change in hydrological cycle, etc. Hence there is a need for an alternative source of fuel that is clean and sustainable. Among the many resources considered as an alternative power source, hydrogen is considered one of the most promising candidates. To use hydrogen commercially, appropriate hydrogen storage system is required. Various options to store hydrogen for onboard use include gaseous form in high-pressure tanks, liquid form in cryogenic conditions, solid form in chemical or metal hydrides, or by physisorption of hydrogen on porous materials. One of the emerging porous materials are metal-organic frameworks (MOFs) which provide several advantages over zeolites and carbon materials because the MOFs can be designed to possess variable pore size, dimensions, and metrics. In general, MOFs adsorb hydrogen through weak interactions such as London dispersion and electrostatic potential which lead to low binding enthalpies in the range of 4 to 10 kJ/mol. As a result, cryogenic conditions are required to store sufficient amounts of hydrogen inside MOFs. Up to date several MOFs have been designed and tested for hydrogen storage at variable temperature and pressure levels. The overall results thus far suggest that the use of MOFs for hydrogen storage without chemical and electronic modifications such as doping with electropositive metals or incorporating low density elements such as boron in the MOFs backbone will not yield practical storage media. Such modifications are required to meet gravimetric and volumetric constraints. With these considerations in mind, we have selected a Cr-based MOF (MIL-101; Cr(F,OH)-(H2O)2O[(O2C)-C6H4-(CO2)]3•nH2O (n ≈ 25)) to investigate the impact of nickel inclusion inside the pores of MIL-101 on its performance in hydrogen storage. MIL-101 has a very high Langmuir surface area (5900 m2/g) and two types of mesoporous cavities (2.7 and 3.4 nm) and exhibits exceptional chemical and thermal stabilities. Without any modifications, MIL-101 can store hydrogen reversibly with adsorption enthalpy of 10 kJ/mol which is the highest ever reported among MOFs. At 298 K and 86 bar, MIL-101 can store only 0.36 wt% of hydrogen. Further improvement of hydrogen storage to 5.5 wt% at 40 bar was achieved only at low temperatures (77.3 K). As reported in the literature, hydrogen storage could be improved by doping metals such as Pt. Doping is known to improve hydrogen storage by spillover mechanism and Kubas interaction. Hence we proposed that doping MIL-101 with a relatively light metal possessing large electron density could improve hydrogen adsorption. Preferential Ni doping of the MIL-101’s large cavities which usually do not contribute to hydrogen uptake is believed to improve hydrogen uptake by increasing the potential surface in those cavities. We have used incipient wetness impregnation method to dope MIL-101 with Ni nanoparticles (NPs) and investigated their effect on hydrogen uptake at 77.3 K and 298 K, at 1 bar. In addition, the impact of metal doping on the surface area and pore size distribution of the parent MIL-101 was addressed. Metal content and NPs size was investigated by ICP and TEM, respectively. Furthermore, crystallinity of the resulting doped samples was confirmed by Powder X-ray Diffraction (PXRD) technique. The results of our studies on the successful doping with Ni NPs and their impact on hydrogen adsorption are discussed.

An in situ deposition procedure was developed for the nanopeapod (NPP) formation of NiAu nanoparticles inside preformed acid-exchanged hexaniobate nanoscrolls (HNB). Metal salt precursors of Ni(acac)2 and HAuCl4∙3H2O were reduced in solution under mild synthetic conditions in the presence of the preformed acid-exchanged hexaniobate nanoscrolls. Two of the surfactants used for the formation of the nanoparticles were oleylamine and triphenylphosphine oxide (TTPO). Reaction conditions were studied and modified to produce well-defined NiAu@HNB NPP systems, with monodispersed particles evenly filling and orienting within the nanoscrolls. The synthetic parameters studied were both time and temperature, with the most well-defined peapod systems being those produced from lower temperatures (100°C) and longer reaction times (60 minutes). NiAu@HNB NPPs synthesized under these conditions yielded a narrow size distribution of NiAu nanoparticles, ranging ~ 4 – 10 nm in diameter, evenly filled and oriented within the inner diameter of hexaniobate nanoscrolls (ranging ~2 μm in length).

M. Tech. (Department of Chemistry, Faculty of Applied and Computer Sciences), Vaal University of Technology. / Lead, nickel and cobalt dithiocarbamates complexes were synthesized using methanol and water as solvents. All complexes were refluxed at 60 °C, cooled at room temperature, washed with methanol to remove the impurities and dried under the fume hood. A combination of Fourier transformer infrared (FTIR), elemental analysis (EA) and thermogravimetric analysis (TGA) were used to characterize these complexes. There was shifting of bands from low to high frequencies of the dithiocarbamates complexes compared to benzimidazole derivatives. The absence of the N-H band and the presence of new C=S bands confirmed that the complexes can be used in the preparation of metal sulphide nanoparticles. Elemental analysis showed that there was a percentage mismatch for the complexes I, III, IV and V. Complexes II and VI calculated percentages were within the limits with the found percentages except for sulphur which was low. The TGA curves decomposed to form a mixture of metal and metal sulphides for complex I, II, III and IV except for complex VI which gave metal sulphide only. All benzimidazole complexes decomposed at higher temperatures and were considered as stable complexes. Lead sulphide (PbS) is an important group IV-VI metal chalcogenide semiconductor. It has a direct narrow band gap of 0.41 eV at 300K and a large excitonic Bohr radius of 18 nm. Lead sulphide absorption band can be tuned to anywhere between near IR to UV (0.4μm) covering the entire visible spectrum, while achieving the quantum confinement region. The synthesis of lead sulphide nanoparticles was conducted by varying the effect of the reaction conditions such as the type of capping agents and temperature. Lead dithiocarbamate complex derived from benzimidazole, [Pb(S2N2C8H5)2] was thermolysed in hexadecylamine (HDA) and trioctylphosphine oxide (TOPO) at different reaction temperatures (140, 160 and 180 °C) to produce HDA and TOPO capped PbS nanoparticles. The nanoparticles were characterized using X-ray diffraction (XRD) for structural analysis, transmission electron microscopy (TEM) for shape and size, Ultraviolet visible (UV/Vis) and Photoluminescence (PL) spectroscopy for optical properties. An increase in temperature gave a decrease in the sizes of the nanoparticles when using the HDA capped lead benzimidazole dithiocarbamate complex. The observed morphology was cubes. TOPO capped lead benzimidazole dithiocarbamate complex gave no specific trend when temperature was varied. A cross-like layer with quasi spherical particles on top was observed at 160 °C. At 180 °C, the cross-like layer decomposed into rods- like materials with quasi spherical particles on top for TOPO capped PbS nanoparticles. For lead 2-methylbenzimidazole [Pb(S2N2C9H7)2] dithiocarbamate complex, TOPO capped PbS produced agglomerated cubic morphology at low temperature but as the temperature was increased agglomerated cylindrical shapes were observed. HDA capped PbS produced polydispersed nanocubes which were increasing in size when the temperature was increased. Nanoparticles displayed a blue shift in band edges with good photoluminescence behaviour which was red shifted from their respective band edges all temperatures and capping agents. XRD confirmed the crystal structure of cubic phase (galena) of PbS at all temperatures except for HDA capped PbS nanoparticles at 140 °C from lead benzimidazole dithiocarbamate complex which confirmed the crystal structure of face-centred cubic phase of PbS nanoparticles. Nickel sulphide has much more complicated phase diagram than cobalt sulfides and iron sulfides. Their chemical composition has many crystalline phases such as α-NiS, β=NiS, NiS2, Ni3S2, Ni3S4, Ni7S6 and Ni9S8. Ni3S2 phase has shown potential as a low-cost counter electrode material in dye sensitised solar cells, while the α-NiS phase has been applied as a cathode Material in lithium-ion batteries. The synthesis of nickel sulphide nanoparticles was done by varying the effect of the reaction conditions such concentration and temperature. Nickel benzimidazole dithiocarbamate [Ni(S2N2C8H5)2] and nickel 2-methylbenzimidazole [Ni (S2N2C9H7)2] dithiocarbamates complexes were thermolysed in hexadecylamine (HDA) at different reaction temperatures (140, 160 and 180 °C) and precursor concentrations (0.30, 0.35 and 0.40 g) to produce HDA capped NiS nanoparticles. It was observed that increasing both temperature and precursor concentration increased the size of the nanoparticles. Anisotropic particles were observed for both complexes when varying precursor concentration and temperature. Nickel benzimidazole dithiocarbamate complex produced stable shapes (spheres and cubes) of nickel sulphide nanoparticles. Nickel 2-methylbenzimidazole dithiocarbamate complex produced a mixture of spheres, cubes, triangles and rods nickel sulphide nanoparticles at all concentrations. But when varying temperature, it only produced that mixture at 160 °C. The optical measurements supported the presence of smaller particles at all temperatures and concentrations. XRD showed the presence of C7OS8 and pure nickel as impurities. However, the crystal structure of cubic Ni3S4 was observed at low temperatures and an introduction of monoclinic NixS6 at high temperature (180 °C) when varying temperature for both complexes. When varying concentration using nickel benzimidazole dithiocarbamate complex, XRD showed the presence of NiSO4.6H2O impurities at high temperatures. At 160 °C a mixture of hexagonal NiS and cubic Ni3S4 was observed. At low temperatures only nickel as a metal was found as an impurity and the crystal structure of cubic Ni3S4 was observed. When nickel 2-methylbenzimidazole complex was used, C7OS8 and pure nickel were found as impurities but the crystal structure of cubic Ni3S4 was observed. Cobalt sulphide (CoS) belongs to the family of group II-IV compounds with considerable potential for application in electronic devices. They have a complex phase diagram and their chemical composition have many phases such as Co4S3, Co9S8, CoS, Co1-xS, Co3S4, Co2S3 and CoS2. The synthesis of cobalt sulphide nanoparticles was conducted by varying the effect of temperature on size and shape of the nanoparticles. Nickel benzimidazole dithiocarbamate, [Ni(S2N2C8H5)2] and nickel 2-methylbenzimidazole [Ni(S2N2C9H7)2] complexes were thermolysed in hexadecylamine (HDA) at different reaction temperatures (140, 160 and 180 °C) to produce HDA capped CoS nanoparticles. Cobalt benzimidazole dithiocarbamate complex produced close to spherical shapes nanoparticles at all temperatures. The images showed that as temperature was increased, the size of the particles decreased. All the main reflection peaks were indexed to face-centred cubic Co3S4 and there were some impurities of C7OS8 at all temperatures. The optical measurements supported the presence of smaller particles at all temperatures. Cobalt 2-methylbenzimidazole dithiocarbamate complex produced big and undefined morphology. The optical properties were also featureless and XRD only showed impurities of C7OS8. The impurity is thought to be generated from a side reaction between benzimidazole and carbon disulphide to give this persistent organic moiety.

TESIS PARA OPTAR AL GRADO DE MAGÍSTER EN POLÍTICAS PÚBLICAS / Este trabajo estudia los determinantes de no estudiar y no trabajar de los j ovenes entre 15 y 29 a~nos en Chile, con especial foco en las diferencias por g enero de los j ovenes y en la separaci on por tramo de edad, dada la heterogeneidad de la muestra en estudio. Se utilizan los datos de la Encuesta de Caracterizaci on Socioecon omica (CASEN) 2013, adem as de la serie completa CASEN para estudiar la evoluci on de los NINI en el tiempo. Para lograr el objetivo, se implementan modelos de elecci on univariada en las decisiones de no estudiar, no trabajar, y ser NINI (ambas categor as de forma simult anea), y adem as se propone un modelo de elecci on bivariada en las decisiones de no estudiar y no trabajar. La hip otesis principal para proponer este modelo, es que las decisiones de no estudiar y no trabajar est an correlacionadas. Los datos descriptivos muestran que: i) El porcentaje de NINIs ha disminuido desde 1990 hasta 2013. ii) Los NINIs se concentran en quintiles de menores ingresos, mientras dicho porcentaje disminuye en los de mayores ingresos. iii) En total son 790.563 j ovenes NINI, que se dividen en 34% de hombres NINI y 66% de mujeres NINI. Dichas mujeres en su mayor a ayudan en la casa o quehaceres del hogar, se encuentran embarazadas o en maternidad, terminaron de estudiar, y no tienen con quien dejar a los ni~nos. Entre los principales resultados de la investigaci on, controlando por regi on y areas urbana y rural, se encuentra que: a) Las variables de caracterizaci on del joven y del hogar en que este vive resultaron tener impacto signi cativo en las decisiones analizadas. b) Al incorporar variables que re ejan la presencia de NINIs en el hogar, se encuentra que estas variables tienen un fuerte impacto y signi cativo, lo cual sugiere que aquellos hogares con presencia de j ovenes NINI en el mismo, tienden a reproducir esta condici on en aquellos j ovenes que no lo son. c) Se encuentra un signi cativo y negativo coe ciente de correlaci on, indicando que las decisiones de no estudiar y no trabajar est an relacionadas y existe un trade-o entre dichas decisiones.