Spectroscopy is the study of matter interacting with electromagnetic radiation (e.g., light). The electromagnetic spectrum in Figure 1 illustrates the many different types of electromagnetic radiation, including gamma rays (γ-rays), X-rays, ultraviolet (UV) radiation, visible light, infrared (IR) radiation, microwaves, and radio waves. The frequency (ν) and wavelength (λ) ranges associated with each form of radiant energy are also indicated in Figure 1.

Introduction to Spectroscopy

PM2.5 in China: Measurements, sources, visibility and health effects, and mitigation

Colour Chemistry  By R L M Allen Pp xii+336 (Thomas Nelson and Sons: London, 1971) £5

Dyes and Pigments

Electricity is conceivably the most multipurpose energy carrier in modern global economy, and therefore primarily linked to human and economic development. Energy sector reform is critical to sustainable energy development and includes reviewing and reforming subsidies, establishing credible regulatory frameworks, developing policy environments through regulatory interventions, and creating market-based approaches. Energy security has recently become an important policy driver and privatization of the electricity sector has secured energy supply and provided cheaper energy services in some countries in the short term, but has led to contrary effects elsewhere due to increasing competition, resulting in deferred investments in plant and infrastructure due to longer-term uncertainties. On the other hand global dependence on fossil fuels has led to the release of over 1100 GtCO2 into the atmosphere since the mid-19th century. Currently, energy-related GHG emissions, mainly from fossil fuel combustion for heat supply, electricity generation and transport, account for around 70% of total emissions including carbon dioxide, methane and some traces of nitrous oxide. This multitude of aspects play a role in societal debate in comparing electricity generating and supply options, such as cost, GHG emissions, radiological and toxicological exposure, occupational health and safety, employment, domestic energy security, and social impressions. Energy systems engineering provides a methodological scientific framework to arrive at realistic integrated solutions to complex energy problems, by adopting a holistic, systems-based approach, especially at decision making and planning stage. Modeling and optimization found widespread applications in the study of physical and chemical systems, production planning and scheduling systems, location and transportation problems, resource allocation in financial systems, and engineering design. This article reviews the literature on power and supply sector developments and analyzes the role of modeling and optimization in this sector as well as the future prospective of optimization modeling as a tool for sustainable energy systems.

Sustainable energy systems: Role of optimization modeling techniques in power generation and supply—A review

Perspectives on the feasibility of using microalgae for industrial wastewater treatment.

Characteristics of fine-grained soils primarily depend on their specific-surface area and hence, reliable determination of this parameter is essential. In this context, researchers have employed quite sophisticated instruments (viz., a BET surface area analyzer, the mercury intrusion porosimetry, internal reflectance spectroscopy, X-Ray diffraction and gas pycnometer etc.) and methodologies (viz., sorption of Methylene Blue dye, Ethylene Glycol Monoethyl Ether and p-Nitrophenol) to determine specific-surface area of these soils. However, most of these methodologies are found to be quite tedious, cost and time intensive. Apart from this, the results obtained are contentious due to the inherent limitations associated with either the instruments employed or the basic assumptions made for computing the specific-surface area of the soil. Hence, it becomes mandatory to evaluate the efficiency of these methodologies for determining specific-surface area of fine-grained soils. With this in view, different types of soils were considered in this study and their specific-surface area was determined, by following different methodologies, and the results were evaluated critically. In addition, attempts were made to develop relationships between the basic properties of fine-grained soils (viz., liquid limit, cation-exchange capacity, activity, and free swell index) and the specific-surface area. These relationships will be of immense help to the practicing engineers and research fraternity.

Comparison of Methods for Determining Specific-surface Area of Fine-grained Soils

Flue gas conditioning for reducing suspended particulate matter from thermal power stations

Coagulation is an important step in the physicochemical treatment of wastewater. Due to the disadvantage associated with the commonly used inorganic metal salts and other synthetic polymers, in recent years, research on the use of natural organic polymers as coagulant is gaining importance. In this study, the coagulation potential of alginate extracted from brown algae, Sargassum sp. for the removal of Congo red dye from aqueous solution has been identified. The yield of alginate extraction was found to be 40.8%. The extracted alginate was characterized by Fourier transform infrared spectroscopy and Scanning electron microscopy techniques. The effect of initial pH (4–6), alginate dose (10–60 mg/L), calcium dose (1–6 g/L), and initial dye concentration (50–250 mg/L) on dye removal have been investigated. It is inferred from the study that the maximum removal of dye (96%) was achieved with increasing alginate and calcium dose for increasing dye concentration, at pH 4. The obtained results were compa...

Performance study on algal alginate as natural coagulant for the removal of Congo red dye

Influence of flue gas conditioning on fly ash characteristics

Rivers are the mostly vulnerable water bodies due to carrying off and assimilating pollutants from both point sources and non-point sources. This study deals with the metal pollution in sediments of the Cooum River, Chennai, India. Eleven sampling stations were selected along the 18 km stretch of the Cooum River, which lies in the urban part of the Chennai City and the concentration of metals such as As, Zn, Mn, Ni, Co, Cr, Cu, Pb, Cd, and Hg in the sediments were determined. The study reveals a progressive increase in the concentration of metals in the downstream due to increase in domestic and industrial drainage (out falls) into the river. Spatial distribution of sediment particle size indicated the dominance of smaller particles ranging from 425 to 75 µm. The concentration of metals in the Cooum River sediments was in the following order: As > Zn > Cr > Cu > Pb > Cd > Hg. Significant positive correlations exist between Cd and Zn, Cu and Pb, Cd and Hg, and Cr and Hg. Ecological risk indices denote predominant levels (> 70%) of cadmium throughout the sampling points as indicated from contamination factor. Potential ecological risk assessment specified the alarming levels of cadmium and mercury above the standard limits in the sediments assessed. Based on the observations, it is evident that the Cooum River is highly polluted and it becomes essential that the urban effluents should not be overlooked before their discharge into the river.

S. Shanthakumar

Papers

Comparison of Methods for Determining Specific-surface Area of Fine-grained Soils

Flue gas conditioning for reducing suspended particulate matter from thermal power stations

Performance study on algal alginate as natural coagulant for the removal of Congo red dye

Influence of flue gas conditioning on fly ash characteristics

Distribution of Metal Contamination and Risk Indices Assessment of Surface Sediments from Cooum River, Chennai, India