3 resultados para TAPAJOS GOLD PROVINCE
em CORA - Cork Open Research Archive - University College Cork - Ireland
Resumo:
The past two decades has seen a dramatic upheaval in the international world order: the end of the Cold War, the 9/11 attacks and the subsequent 'War on Terror', increased Jihadist activities, the accelerated pace of globalization, climate change and the 2008 global financial crisis have contributed to fear, uncertainty, poverty, conflict, massive displacements of populations of asylum seekers and refugees globally and a proliferation of Protracted Refugee Situations (PRS), defined as situations in which refugees have been in exile 'for 5 years or more after their initial displacement, without immediate prospects for implementation of durable solutions. In the past two decades there has been a huge proliferation of these with more than 7.2 million refugees now trapped in these PRS, with a further 16 million internally displaced persons (IDPs) trapped in camps within their own countries. The Dadaab refugee complex in Kenya, which of as March 2012, holds over 463,000 refugees, is the most significant and extreme example in recent times of a PRS. It was established in 1991 following the collapse of the Somali Government of Dictator Siad Barre, and the disintegration of Somalia into the chaos that still exists today. PRS such as Dadaab raise particular issues about humanitarianism in terms of aid, protection, security, human rights and the actions (or inaction) of the various stakeholders on an international, national and local level. This thesis investigates these issues by the use of a case study methodology on Dadaab as a PRS, framed in the context of humanitarianism and in particular the issues that arise in terms of how the international community, the UN system and individual states provide assistance and protection to vulnerable populations. Although the refugee camps have been in existence (as of 2012) for over 20 years, there has never been such a detailed study of Dadaab (or any other PRS) undertaken to date and would be of interest to academics in the areas of international relations, refugee/migration studies and global Governance as well as practitioners in both humanitarian response and development
Resumo:
This work explores the functionalization of an organic-inorganic MoS2 lamellar compound, prepared by a Chemical Liquid Deposition Method (CLD), that has an interlamellar distance of ~5.2 nm, using clusters of gold nanoparticles. The gold nanoparticles have a mean diameter of 1.2 nm, a stability of ~85 days, and a zeta potential measured to be ζ = -6.8 mV (solid). The nanoparticles are localized in the hydrophilic zones, defined by the presence of amine groups of the surfactant between the lamella of MoS2. SEM, TEM, EDAX and electron diffraction provide conclusive evidence of the interlamellar insertion of the gold nanoparticles in the MoS2.
Resumo:
This thesis investigates the application of plasmonic gold nanostructures for mercury detection. Various gold and silver single nanostructures and gold nanostructure assemblies were characterised in detail by correlated single nanostructure spectroscopy and electron microscopy. Several routes for mercury detection were explored: plasmon resonance energy transfer (PRET) upon Hg2+ binding to immobilised gold nanoparticle-organic ligand hybrid structures and amalgamation of single immobilised gold nanorods upon chemical and upon electrochemical reduction of Hg2+ ions. The amalgamation approach showed large potential with extraordinary shifts of the nanorods’ scattering spectra upon exposure to reduced mercury; a result of compositional and morphological change induced in the nanorod by amalgamation with mercury. A shift of 5 nm could be recorded for a concentration as low 10 nM Hg2+. Through detailed time-dependent experiments insights into the amalgamation mechanism were gained and a model comprising 5 steps was developed. Finally, spectroelectrochemistry proved to be an excellent way to study in real time in-situ the amalgamation of mercury with gold nanorods paving the way for future work in this field.