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Heat energy storage is pivotal in modern times. However, the technology to efficiently stored heat energy is still in the research stage. Heat energy storage is possible through phase change material, exothermic chemical reactions, and solar ponds. The latter uses a natural phenomenon that relies on solar Energy and convective heat transfer. Solar ponds can store more heat energy throughout the day than other processes and meet higher energy demands. The working principle of a typical solar pond can be adopted to develop a compact setup that can store sufficient heat energy to meet the heat energy demand of a small family. Salinity gradient solar ponds are used for heat storage to meet the demand of rural and urban communities in arid and semiarid zones around the globe. Often the solar ponds are constructed on the ground by storing a large volume of salt water. The performance of the solar pond is affected by the intensity of solar radiation. In this study, a compact solar pond is constructed using aluminum plates and a glass cover. Sea water was used to store solar radiation in this experiment. The experiment was carried out in South India during the winter season when the intensity of solar radiation was minimum. The study aims to determine the performance of the solar pond and its thermal properties under low sunshine. Heat storage mediums comprising paraffin wax and additives of nanoparticles of graphene and carbon nanotubes were used to enhance the heat storage capacity of the solar pond. It was found that compared to the simple salinity gradient solar pond, the heat storage medium with carbon nanotube nanoparticles increased the maximum temperature attained by 26.5%. The carbon nano tubes infused phase change material increased the heat transfer, heat transfer coefficient, and the heat stored in the saline water by 244%, 713%, and 83.3%, respectively. It is concluded that the carbon nano tubes and phase change material augmented the performance of the solar pond even while the intensity of solar radiation was low. [ABSTRACT FROM AUTHOR]

Pesticides play a significant key role in the agriculture sector. In India, there is a sharp increase in pesticides consumption in recent years, leading to severe implications. Due to the rapid use of pesticides, there is residue in the food, which leads to poor effects on human health. Furthermore, the discharge of various pesticides into water bodies from the industries and agricultural activities leads to environmental concerns. Because of their toxicity, persistent nature, and bioaccumulation potential, it is essential to remove pesticides from water. Nanoparticles are tiny particles whose size ranges from 1 to 100 nm. Nanomaterials have a large surface area, a large number of active sites, and high reactivity. Therefore, nanotechnology is a fast, efficient, and economical process. Nanotechnology plays an influential role in the removal of various pesticides from water and wastewater. In recent years, various nanomaterials, such as TiO2, ZVI, Zn, and rGO (reduced graphene oxide), CNTs (carbon nanotubes), and polymer-supported nanomaterials are widely used for the removal of pesticides from water. In this review, detailed information about various pesticides and their removal with the help of nanocomposites has been discussed. [ABSTRACT FROM AUTHOR]

Biodiesel is considered an immediate substitute for the fossil diesel as the fuel properties, such as calorific value, density, ash content and acid value are comparable to the diesel. In India, pongamia oil has considerable potential for the biodiesel production. The pongamia oil biodiesel has lower volatility and slightly higher viscosity than the diesel. Hence the pongamia oil biodiesel fuelled diesel engine results in lower thermal efficiency as compared to the diesel. The carbon nanotubes (CNTs) were used in this work as additive to the pongamia oil biodiesel, to enhance the atomization and to reduce the ignition delay of the pongamia oil biodiesel. The CNTs were added to the pongamia oil biodiesel with different dosages and subjected to ultrasonication for 60 min, to prepare homogenous mixture. The engine tests were conducted on a single cylinder diesel engine without making any modifications in the fuel injection system. The addition of CNTs to the pongamia oil biodiesel resulted in higher brake thermal efficiency at higher loads between 75 to 100 % of the full load. From the engine tests, it was observed that the CNTs improves the engine thermal efficiency and reduces the CO, HC and smoke emissions of the diesel engine depends upon the CNT dosage. This is due to shorten ignition delay caused by the CNTs which improves the combustion of the pongamia oil biodiesel. The optimum CNT dosage of 50 mg/l results in 4% increase in thermal efficiency and reduces the CO, HC and smoke emissions by 20.33, 25 and 12.5% respectively at full load. [ABSTRACT FROM AUTHOR]

Delivering the right amount of fluoride to drinking water protects the teeth from decay and reduces the risk of cavities. Nonetheless, fluorosis has been diagnosed as the result of excessive exposure of fluoride, which induces brain impairment, muscle disorders and hyperactivity. Fluoride ingestion during the formation of the tooth enamel is the main reason for fluorosis, which is characterized by hypomineralization. Dissolution of fluoride-containing rock minerals contributes to naturally occurring fluoride contamination in water. The intentional addition of fluoride to water in dental care is alarming in growing countries such as India. This article reviews the origin of fluoride, the analysis of fluoride derivatives and the technologies to remove fluoride from water. The manuscript presents adsorption techniques for fluoride removal, using different types of adsorbents. The adsorption capacities of adsorbents under various conditions, such as contaminant concentration, adsorbent dosage, time, pH and temperature, are presented. Adsorbent types include alumina, zeolites, organic waste, shell-based and carbon-based including graphite and carbon nanotubes. Defluoridation of water using clays and muds, modified activated alumina, chitosan derivatives and composites are also discussed. [ABSTRACT FROM AUTHOR]

Formation of carbon nanostructures of diameters less than 50 nm with an aspect ratio of 100 is achieved during the chemical demineralization of Indian coal. Demineralization was carried out using an aqueous solution of sodium hydroxide at 90°C for 5 hours. Structural analysis using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) revealed that removal of the inorganic layer, anisotropically embedded in the carbon layers of the coal, had a strong influence on nanostructure formation. The concentration of alkali and the ratio of solid (coal)-to-liquid (alkali reagent) crucially determine the extent of demineralization and thereby affect the nanostructure formation. [ABSTRACT FROM AUTHOR]

This paper reports on a scientometric study of 834 articles on Carbon nanotube research in India spanning over the years 1999 to 2012 downloaded from Web of Science. The study analyses literature growth trends, which shows an initiation of potential growth of research in this subject since 2008. It also examines collaborations with different countries. The authorship pattern, document types involved and active Indian institutions co-coordinating research in this subject have also been studied. Bradford law of scattering was applied to identify the core journals and Lotka's law to study the authors' productivity pattern. [ABSTRACT FROM AUTHOR]

Abstract  China, Russia, and India are playing an increasingly important role in global nanotechnology research and development (R&D). This paper comparatively inspects the paper and patent publications by these three countries in the Thomson Science Citation Index Expanded (SCI) database and United States Patent and Trademark Office (USPTO) database (1976–2007). Bibliographic, content map, and citation network analyses are used to evaluate country productivity, dominant research topics, and knowledge diffusion patterns. Significant and consistent growth in nanotechnology papers are noted in the three countries. Between 2000 and 2007, the average annual growth rate was 31.43% in China, 11.88% in Russia, and 33.51% in India. During the same time, the growth patterns were less consistent in patent publications: the corresponding average rates are 31.13, 10.41, and 5.96%. The three countries’ paper impact measured by the average number of citations has been lower than the world average. However, from 2000 to 2007, it experienced rapid increases of about 12.8 times in China, 8 times in India, and 1.6 times in Russia. The Chinese Academy of Sciences (CAS), the Russian Academy of Sciences (RAS), and the Indian Institutes of Technology (IIT) were the most productive institutions in paper publication, with 12,334, 6,773, and 1,831 papers, respectively. The three countries emphasized some common research topics such as “Quantum dots,” “Carbon nanotubes,” “Atomic force microscopy,” and “Scanning electron microscopy,” while Russia and India reported more research on nano-devices as compared with China. CAS, RAS, and IIT played key roles in the respective domestic knowledge diffusion. [ABSTRACT FROM AUTHOR]

The present study aims at a detailed experimental study of a passive-type solar air heater (SAH) on the effect of coating the absorber plate with higher thermal conductive black paint under forced circulation method and studied under the climatic conditions of Chennai. Furthermore, to enhance the thermal performance index of conventional SAH, additional enhancement such as coating and staggered fins are fixed to the absorber plate of duct which simultaneously increases the turbulent intensity, kinetic energy to enhance the temperature of outlet air. Comparisons are made with a solar air heater without coating and staggered fin in order to assess the thermal performance. Experiments were conducted on a continuous basis and the flow rates of air flowing through the duct are varied. Experimental results revealed that the effect of coating improved the plate temperature to a maximum of 102 °C while the modified SAH coated with ordinary black paint and staggered fin arrangement is found as 95 °C for the flow rate of m f  = 0.03 kg/s. The difference in temperature between exit and inlet of conventional SAH with coating alone is found as 13.09 °C at a flow rate of m f  = 0.03 kg/s whereas the average thermal efficiency is found as 22.3%. Similarly, increasing the mass flow rate from 0.13 to 0.22 kg/s has no significant improvement in average daily thermal efficiency, whereas the temperature difference decreases. The coating of absorber plate with higher thermal conductivity paint and increased turbulence created between the duct by using staggered fin improved the temperature of exit air by 63, 64, 38 and 35% for air flow rates of 0.03, 0.04, 0.13 and 0.22 kg/s respectively. On a flat absorber with coating, the average increase in temperature is found at 6.3% compared to that of SAH coated with ordinary black paint. The hourly thermal efficiency of the conventional type SAH with coating exhibited an enhancement of about 5% in thermal efficiency as compared to that of conventional type with black paint coating alone for the same climatic condition, whereas the thermal efficiency of staggered fin SAH with coating alone is enhanced by 7.5%. With staggered fin arrangement in the absorber plate, heat absorption by the air is increased with CNT-coated absorber and excessive turbulence produced by the fins enhanced the average temperature difference from 13.5 to 20.3 °C. The cost per unit kW of conventional type SAH with CNT-doped black paint reduced from 0.01754 $ to 0.00832 $/kW while varying the flow rate from 0.031 to 0.22 kg/s.

The peculiar characters and industrial applications of carbon nanotubes (CNTs) and carbon nanoballs (CNBs) have attracted the interests of technologists, scientists, and policy-makers. Here, authors have synthesized CNTs and CNBs through MCL (molten caustic leaching) method from ten coal samples belonging to Ib valley Basin, Odisha, India. HRTEM (High-Resolution Transmitted Electron Microscopy), FTIR (Fourier Transform Infrared) spectroscopy and XRD (X-ray Diffraction) analyses appraised the presence of carbon nano-particles with varied sizes in the MCL products. The nanoballs are in the range of 52-64 nm and the nanotubes are within the range of 7-15 nm in diameter. The petrographic parameters viz. various macerals and rank, as well as a measure of aliphatic bonds, have a significant impact on the amount of yield, purity, and quality of CNTs/CNBs. Carbon nano-products (CNPs) yield is increased with the fixed carbon content and decreased with volatile matter yield and mineral matter present in coals. Oxygen and hydrogen content in coal have decreased the carbon nano-products yield. Optical microscopic study of coals revealed that the carbon nano-products (CNPs) formation is favored with an increase in vitrinite and liptinite and decrease with inertinite macerals. Inertinite macerals, characterized by high aromaticity with aromatic rings of large size, do not take part (little participation) in reaction with alkalies and in acid treatment. The aliphatic bonds and chains in liptinites and vitrinites help in carbon nano-products synthesis. The proposed empirical equation PEC (petrographic estimate of CNPs) seems to indicate the amount of CNPs yield through the MCL process. The MCL may be a proficient technique for the synthesis of nano‑carbons as well as the removal of mineral matter from coals. Unlabelled Image • Maceral and mineral reactivity in CNPs (carbon nano-products) development • PEC (petrographic estimate of CNPs) predicts the amount of CNPs yield. • Vitrinite and liptinite favor CNPs production • CNPs from bituminous coal through molten caustic leaching (MCL) process • HRTEM of carbon nano-products [ABSTRACT FROM AUTHOR]