Traditionally, for the planning and assessment of solar energy systems, the amount of solar radiation (sunlight) incident on the Earth’s surface is assumed to be constant over the years. However, with changing climate and air pollution levels, solar resources may no longer be stable over time and undergo substantial decadal changes. Observational records covering the past decades confirm long-term changes in this quantity. Here we examine how the latest generation of climate models used for the 5th IPCC report projects potential changes in surface solar radiation over the coming decades, and how this may affect, in combination with the expected greenhouse warming, solar power output from photovoltaic (PV) systems. For this purpose, projections up to the mid 21st century from 39 state of the art climate models from the Coupled Model Intercomparison Project Phase 5 (CMIP5) are analysed globally and for selected key regions with major solar power production capacity. The large model ensemble allows to assess the degree of consistency of their projections. Models are largely consistent in the sign of the projected changes in solar radiation under cloud-free conditions as well as surface temperatures over most of the globe, while still reasonably consistent over a considerable part of the globe in the sign of changes in cloudiness and associated changes in solar radiation. A first order estimate of the impact of solar radiation and temperature changes on energy yields of PV systems under the RPC8.5 scenario indicates statistically significant decreases in PV outputs in large parts of the world, but notable exceptions with positive trends in large parts of Europe, South-East of North America and the South-East of China. Projected changes between 2006 and 2049 under the RCP8.5 scenario overall are on the order of 1%/decade for horizontal planes, but may be larger for tilted or tracked planes as well as on shorter (decadal) timescales.

Projections of long-term changes in solar radiation based on CMIP5 climate models and their influence on energy yields of photovoltaic systems

Characterization of heavy metal pollution in an anthropogenically and geologically influenced semi-arid region of east India and assessment of ecological and human health risks.

Fluoride abundance and their release mechanisms in groundwater along with associated human health risks in a geologically heterogeneous semi-arid region of east India

Influence of cooling rate on the microstructure and properties of a new wear resistant carbidic austempered ductile iron (CADI)

Natural springs which originate from hilly areas of Skardu in Pakistan make their route downward and are utilized by the public as they passes from residential areas. Due to weathering processes in mountainous regions, these springs can be the source of various trace elements and pollutants. Keeping in mind the same concept, ten mostly used freshwater springs were selected to evaluate their drinking water quality in the Skardu region. Three samples of water from each spring (start/mouth, 100 m away from the mouth, and 200 m away from mouth) were collected and analyzed for water quality via Water Quality Index (WQI). The main parameters of spring water were recorded in the laboratory as electrical conductivity (EC), total dissolved solids (TDS), residual sodium carbonate (RSC), and sodium adsorption ratio (SAR), and secondary parameters, i.e., Kelley’s ratio (KR), permeability index (PI), and WQI, were derived. Besides these parameters, heavy metal pollutants (Cd, Cr, Mn, and Cu) were also determined from the water samples. The results showed that the assessed parameters TDS, SSP, KR, and PI were found within the safer limits of drinking water as prescribed by the Pak-EPA and WHO. However, among trace elements, only Cd (0.03 mg L−1) was found above the permissible limits of 0.01 mg L−1 as given by the GOP-EPA (2008) and WHO (1996) at Shigri Bala spring 200 m away. Similarly, at 2 ft from the mouth of Chumig S1 spring, its concentrations were recorded 0.03 mg L−1, and at Benazir Chowk spring (100 m away), it was found 0.02 mg L−1. In general, the Water WQI demonstrates that springs have good water quality. Our findings are useful for the environmental protection managers and citizens of the Skardu concerned with the water quality of the springs.

Surface water quality assessment of Skardu springs using Water Quality Index

A study was conducted in seven geothermal springs located in Bakreswar, District Birbhum, West Bengal, India, in order to assess numerous geochemical processes which were responsible for chemical composition of thermal and mineralized water. The study area lies over the Sone, Narmada, and Tapti lineament of Precambrian Chotanagpur Gneissic Complex. Water chemistry has been carried out based on reaction stoichiometry and geo-statistical tools to identify geochemical process. Piper and Gibbs diagram suggest that the spring water belongs to Ca2+-Mg2+-HCO3− + CO32− water type and are controlled by rock dominance. Dissolution and precipitation of calcite, dolomite, gypsum, and fluorite minerals were identified as principle source of major ions in seven geothermal spring water. Principle component analyses revealed that major ions of spring water are derived from geogenic processes such as weathering, dissolution, and precipitation of various minerals. Overall results suggest that major ions of the spring’s water are derived from natural origin because no evidence of anthropogenic sources was observed during the study period. This study has also revealed that water quality of spring’s water is not suitable for drinking purposes and quite suitable for irrigation because of high abundance of Na+, K+, Cl−, and HCO3− ions.

Characterization of hydrogeochemical process and evaluation of water quality of seven geothermal springs, Bakreswar, India

Projection of future daily global horizontal irradiance under four RCP scenarios: An assessment through newly developed temperature and rainfall-based empirical model

Near Net Shape (NNS) manufacturing produces the engineering components closer to its final specification in single stage or minimum number of stages. ADI process technology is one of the NNS manufacturing technologies, currently being followed by the industries for manufacturing of engineering components at competitive price. Austempered Ductile Iron is a new class of engineering material which is being manufactured from high quality Ductile Iron through austempering process. ADI castings provide a unique combination of high strength and toughness coupled with superior wear resistance properties.

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Abbhijit Chowdhury

Papers

Characterization of hydrogeochemical process and evaluation of water quality of seven geothermal springs, Bakreswar, India

Projection of future daily global horizontal irradiance under four RCP scenarios: An assessment through newly developed temperature and rainfall-based empirical model

Near-Net-Shape Manufacturing of Austempered Ductile Iron (ADI) Components