3 resultados para Columbite and rietveld method

em CORA - Cork Open Research Archive - University College Cork - Ireland


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The cyclic phosphazene trimers [N3P3(OC6H5)5OC5H4N·Ti(Cp)2Cl][PF6] (3), [N3P3(OC6H4CH2CN·Ti(Cp)2Cl)6][PF6]6 (4), [N3P3(OC6H4-But)5(OC6H4CH2CN·Ti(Cp)2Cl)][PF6] (5), [N3P3(OC6H5)5C6H4CH2CN·Ru(Cp)(PPh3)2][PF6] (6), [N3P3(OC6H5)5C6H4CH2CN·Fe(Cp)(dppe)][PF6] (7) and N3P3(OC6H5)5OC5H4N·W(CO)5 (8) were prepared and characterized. As a model, the simple compounds [HOC5H5N·Ti(Cp)2Cl]PF6 (1) and [HOC6H4CH2CN·Ti(Cp)2Cl]PF6 (2) were also prepared and characterized. Pyrolysis of the organometallic cyclic trimers in air yields metallic nanostructured materials, which according to transmission and scanning electron microscopy (TEM/SEM), energy-dispersive X-ray microanalysis (EDX), and IR data, can be formulated as either a metal oxide, metal pyrophosphate or a mixture in some cases, depending on the nature and quantity of the metal, characteristics of the organic spacer and the auxiliary substituent attached to the phosphorus cycle. Atomic force microscopy (AFM) data indicate the formation of small island and striate nanostructures. A plausible formation mechanism which involves the formation of a cyclomatrix is proposed, and the pyrolysis of the organometallic cyclic phosphazene polymer as a new and general method for obtaining metallic nanostructured materials is discussed.

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Gold nanoparticles (Au NPs) with diameters ranging between 15 and 150 nm have been synthesised in water. 15 and 30 nm Au NPs were obtained by the Turkevich and Frens method using sodium citrate as both a reducing and stabilising agent at high temperature (Au NPs-citrate), while 60, 90 and 150 nm Au NPs were formed using hydroxylamine-o-sulfonic acid (HOS) as a reducing agent for HAuCl4 at room temperature. This new method using HOS is an extension of the approaches previously reported for producing Au NPs with mean diameters above 40 nm by direct reduction. Functionalised polyethylene glycol-based thiol polymers were used to stabilise the pre-synthesised Au NPs. The nanoparticles obtained were characterised using uv-visible spectroscopy, dynamic light scattering (DLS) and transmission electron microscopy (TEM). Further bioconjugation on 15, 30 and 90 nm PEGylated Au NPs were performed by grafting Bovine Serum Albumin, Transferrin and Apolipoprotein E (ApoE).

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Aim: Alcohol consumption is a leading cause of global suffering. The harms caused by alcohol to the individual, their peers and the society in which they live provokes public health concern. Elevated levels of consumption and consequences have been noted in those aged 18-29 years. University students represent a unique subsection of society within this age group. University authorities have attempted to tackle this issue throughout the past decade. However, the issue persists. Thus, the aim of this study is to contribute to the evidence base for policy and practice in relation to alcohol harm reduction among third-level students in Ireland. Methods: A mixed methods approach was employed. A systematic review of the prevalence of hazardous alcohol consumption among university students in Ireland and the United Kingdom from 2002 to 2014 was conducted. In addition, a narrative synthesis of studies of drinking types evidenced among youths in western societies was undertaken. A cross-sectional study focused on university students’ health and lifestyle behaviours with particular reference to alcohol consumption was undertaken using previously validated instruments. Undergraduate students registered to one university in Ireland were recruited using two separate modes; classroom and online. Studies investigated the impact of mode of data collection, the prevalence of hazardous alcohol consumption and resultant adverse consequences for mental health and wellbeing. In addition a study using a Q-methodology approach was undertaken to gain a deeper understanding of the cultural factors influencing current patterns of alcohol consumption. Data were analysed using IBM SPPS statistics 20, Stata 12, MPLUS and PQ Method. Results: The literature review focusing on students’ alcohol consumption found that there has been both an increase in hazardous alcohol consumption among university students and a convergence of male and female drinking patterns throughout the past decade. Updating this research, the thesis found that two-thirds of university students consume alcohol at a hazardous level, detailing the range of adverse consequences reported by university students in Ireland. Finally, the heterogeneous nature of this drinking was described in a narrative synthesis exposing six types of consumption. The succeeding chapters develop this review further by describing three typologies of consumption, two quantitative and one quali-quantilogical. The quantitative typology describes three types of drinking for men (realistic hedonist, responsible conformer and guarded drinker) and four types for women (realistic hedonist, peer-influenced, responsible conformer and guarded drinker). The quali-quantilogical approach describes four types of consumption. These are defined as the ‘guarded drinker’, the ‘calculated hedonist’, the ‘peer-influenced drinker’ and the ‘inevitable binger’. Discussion: The findings of this thesis highlight the scale of the issue and provide up-to-date estimates of alcohol consumption among university students in Ireland. Hazardous alcohol consumption is associated with a range of harms to self and harms to others in proximity to the alcohol consumer. The classification of drinkers into types signal the necessity for university management, health promotion practitioners and public health policy makers to tackle this issue using a multi-faceted approach.