Search

Noble metal nanoparticles have been extensively studied for use in applications in a diverse range of fields such as optoelectronics, catalysis, sensing, medicine, etc. due to their unique properties that arise as a result of their dimensions. Metal nanoparticles of size less than 3 nm exhibit molecular properties, unlike larger nanoparticles. These molecular nanoparticles are excellent model systems to study the chemistry of nanomaterials at the molecular level as their molecular formulae, crystal structure, chemical composition, electronic structures etc. can be experimentally measured and theoretically calculated. In addition, knowledge of their thermodynamic stability and mechanisms of formation can be leveraged in developing green synthetic routes in order to produce safer products that widen the range of applications, and to develop safer processes that increase manufacturability and decrease waste. Even though nanoparticle research is more focused on the end product and their properties, rather than the process, we have taken a different route of dismantling the M4Ag44(p-MBA)30 nanoparticle synthesis and developing a green route with significantly improved efficiency and an 89% yield. The need of solvent, which contributed to 98% of the waste, was kept to a minimum by using a stoichiometric silver-thiolate polymer as a precursor to intimately mix the metal atoms and ligands, and by forming a paste using a small amount of liquid to promote mass transport. The process mass intensity (PMI), a green metric defined by material input over product output, was decreased by almost 18-fold compared to the solution-phase synthesis. Some toxic chemicals were also removed or replaced throughout the process. This method is very effective for thermodynamically favorable products, and should be useful for other systems too. Alloying of metal nanoparticles is advantageous to achieve new properties. For example, gold-silver bimetallic NPs can be more stable than silver NPs and have better optical properties than gold NPs. Here we have studied the alloying process in M4AuxAg44-x(p-MBA)30 alloy nanoparticles, where 0 = x = 12, and M is a countercation. Two methods were used to synthesize M4AuxAg44-x(p-MBA)30 alloy nanoparticles: (i) co-reduction of gold-thiolate and silver-thiolate with alkali borohydride, and (ii) galvanic-exchange reaction between gold-thiolate and M4Ag44(p-MBA)30 nanoparticles in order to substitute silver with gold. The major findings were: (i) the number of gold atoms incorporated in the alloy was always less than the gold input, (ii) only up to twelve gold atoms were incorporated, (iii) gold prefers to stay at the innermost core energetically in alloy nanoparticles, as shown by the x-ray crystal structure of M4Au12Ag32(p-MBA)30 alloy nanoparticles, (iv) gold atom distributions were generally Gaussian, and (v) addition of gold in silver nanoparticles to create alloys increases the stability against oxidation.

This thesis examines the effectiveness of foreign aid in Nepal, and adds to the growing literature on the issue of aid effectiveness. Until the mid 1960s, almost all development projects in Nepal were financed by foreign aid. Since 1970, the average aid/GDP ratio remains at over 6 per cent, and in 2002 foreign aid financed over 50 per cent of Nepal’s development expenditure. Despite the constant flow of foreign aid and decades of aid-financed development efforts in Nepal, it remains one of the poorest countries in the world, with per capita income of about US$ 243 and almost 40 per cent of the total population living in absolute poverty. This thesis is the first rigorous study of aid effectiveness in Nepal. It examines the issue from three complementary perspectives. First, it looks at aid’s contribution to per capita GDP within the framework of the neoclassical production function. Second, it examines aid’s contribution to Nepal’s gross domestic investment within a framework of the two-gap model. Since aid is channelled through the government, the thesis lastly examines the impact of foreign aid on government expenditure and revenue efforts. Our study uses time-series data for the period 1970-2002, and employs cointegration and the error correction mechanism as the estimation procedure. The results show that aid has a positive and significant relationship between per capita real GDP, savings and investment in the long-run. In addition, we find that aid effectiveness improves in a good policy environment, that is, one characterised by a stable macroeconomy, openness to trade and a liberalised financial sector. The study also finds that bilateral and multilateral aid are equally effective in the long-run. However, grants aid has a stronger positive association with per capita real GDP in the long-run than loans aid. Finally, the relationship between aid and per capita real GDP in the short-run is found to be negative in both aggregate and disaggregated forms. This implies that Nepal, as in the case of most other developing countries, suffers from lack of absorptive capacity and high aid volatility.