Other affiliations: Indian Institute of Technology Guwahati, Indian Institute of Technology Kharagpur, Indian Institutes of Technology ...read more
Bio: Amitava Ghosh is an academic researcher from Indian Institute of Technology Madras. The author has contributed to research in topic(s): Grinding & Machining. The author has an hindex of 23, co-authored 87 publication(s) receiving 1507 citation(s). Previous affiliations of Amitava Ghosh include Indian Institute of Technology Guwahati & Indian Institute of Technology Kharagpur.
Abstract: An investigation has been undertaken to study the compatibility of cutting materials in dry machining of aluminium and Al–Si alloys. Mono or multilayer coated carbide tools with a top coating of TiC, TiN, TiAlN, Al2O3, TiB2, MoS2 etc. on WC–Co inserts already made a major breakthrough in dry machining of ferrous materials. But in contrast dry machining of aluminium and Al-alloys is a great challenge. But wide application of aluminium different parts has increased the need to find out the correct cutting tool. Experimental results of turning test, SEM pictures and chip morphology investigation of the cutting tool after machining clearly reveals the inefficiency of TiC, TiN, TiB2, Al2O3, and AlON in dry machining of aluminium. This is because of the formation of very large amount of metal built-up in both rake and flank surface leading to high magnitude of cutting forces and high roughness of the work-piece during machining. The natural diamond and polycrystalline diamond (PCD) can be used as a cutting tool, when the required shape is attached on the edge/tip for machining non-ferrous materials. But both of them are limited for finishing cut because of high cost. So CVD diamond coated tool is a better option to machine these materials. CVD diamond coated tool was free from built-up edge formation leading to clean cut, low magnitude of cutting forces and improved surface finish of the work-piece. However, performances of the diamond tool depend mainly on adhesion of the diamond coating with the carbide substrate.
Abstract: This paper deals with an investigation of the grindability of Titanium alloy Ti–6Al–4V with monolayered brazed type superabrasive grinding wheels. The experiments, conducted under different grinding environments, showed the performance of the grinding fluids based on an evaluation of grinding forces, chip formation and tool condition. It could be found that conventional grinding fluids like oil or alkaline soap are preferable compared to dry or cryogenic conditions or with MoS 2 coated wheels.
01 Jan 2011-
TL;DR: The new generation of orally disintegrating tablet (ODT) technologies is no longer limited by dosage strength, bitter active pharmaceutical ingredients (APIs), and narrow therapeutic applications.
Abstract: Advancements in oral delivery of active ingredients include a number of technologies, many of which may be classified as oral disintegrating tablets (ODTs). A number of companies have marketed products using various nomenclatures including ODT as well as their own trademarked names. The new generation of orally disintegrating tablet (ODT) technologies is no longer limited by dosage strength, bitter active pharmaceutical ingredients (APIs), and narrow therapeutic applications. Today’s emerging technologies can produce robust, versatile tablets with exceptional taste masking and controlled release, broadening the applications of this dosage form. Over the last decade, ODTs have grown steadily in demand and importance as a convenient, potentially safer alternative to conventional tablets and capsules. ODTs are solid dosage forms that disintegrate in the mouth in less than 60 seconds, and are thus swallowed without the need for water. Since their introduction to the market in the 1980s, ODTs have become one of the fastest‐growing segments of the oral drug delivery industry, and their product pipeline is rapidly expanding. They are particularly beneficial to people who have difficulty taking conventional solid dosage forms, including children, the elderly, patients who have swallowing difficulties, the mentally ill, and the disabled. This review depicts the various formulation techniques, ingredients used, and overview of patented formulations.
01 Jul 2011-Journal of Young Pharmacists
TL;DR: The aim of the present study is to improve the solubility and dissolution rate and in turn the hepatoprotective activity of the drug, by formulating its inclusion complex with beta (β)-cyclodextrin, using different methods.
Abstract: Silymarin is a hepatoprotective agent, having poor water solubility and oral absorption of about 23 - 47%, leading to low bioavailability of the drug. The aim of the present study is to improve the solubility and dissolution rate and in turn the hepatoprotective activity of the drug, by formulating its inclusion complex with beta (β)-cyclodextrin, using different methods. The phase solubility analysis indicates the formation of 1:1 molar inclusion complex of the drug with beta cyclodextrin. Apparent stability constant for Silymarin (K c ) was 722 K−1 with β-cyclodextrin complex. The inclusion complexes were prepared by four different methods, namely, physical mixing, kneading, co-precipitation, and solvent evaporation. The prepared complexes were characterized using differential scanning colorimetry, scanning electron microscopy, and x-ray diffractometry. The inclusion complex prepared by the co-precipitation methods exhibits an overall best result, with respect to the formulation of sustained release formulations. Keywords: Bioavailability, inclusion complexes, silymarin, β-cyclodextrin
01 Sep 1966-Biophysical Journal
TL;DR: The blue-green alga, Anacystis nidulans, was grown in lights of different colors and intensities, and its absorption and fluorescence properties were studied to suggest reduced efficiency of energy transfer from phycocyanin to the strongly fluorescent form of chlorophyll a and perhaps increased transfer to the weaklyorescent form of chlorine a.
Abstract: The blue-green alga, Anacystis nidulans, was grown in lights of different colors and intensities, and its absorption and fluorescence properties were studied. Strong orange light, absorbed mainly by phycocyanin, causes reduction in the ratio of phycocyanin to chlorophyll a; strong red light, absorbed mainly by chlorophyll, causes an increase in this ratio. This confirms the earlier findings of Brody and Emerson (12) on Porphyridum, and of Jones and Myers (8) on Anacystis. Anacystis cultures grown in light of low intensity show, upon excitation of phycocyanin, emission peaks at 600 mμ and 680 mμ, due to the fluorescence of phycocyanin and chlorophyll a, respectively. Changes in the efficiency of energy transfer from phycocyanin to chlorophyll a are revealed by changes in the ratios of these two bands. A decrease in efficiency of energy transfer from phycocyanin to chlorophyll a seems to occur whenever the ratio of chlorophyll a to phycocyanin deviates from the normal. Algae grown in light of high intensity show, upon excitation of phycocyanin, only a fluorescence band at 660 mμ and no band at 680 mμ. This suggests reduced efficiency of energy transfer from phycocyanin to the strongly fluorescent form of chlorophyll a (chlorophyll a2) and perhaps increased transfer to the weakly fluorescent form of chlorophyll a (chlorophyll a1).
01 Jan 1979-
25 Jan 2017-Chemical Reviews
TL;DR: The description of energy transfer, in particular multichromophoric antenna structures, is shown to vary depending on the spatial and energetic landscape, which dictates the relative coupling strength between constituent pigment molecules.
Abstract: The process of photosynthesis is initiated by the capture of sunlight by a network of light-absorbing molecules (chromophores), which are also responsible for the subsequent funneling of the excitation energy to the reaction centers. Through evolution, genetic drift, and speciation, photosynthetic organisms have discovered many solutions for light harvesting. In this review, we describe the underlying photophysical principles by which this energy is absorbed, as well as the mechanisms of electronic excitation energy transfer (EET). First, optical properties of the individual pigment chromophores present in light-harvesting antenna complexes are introduced, and then we examine the collective behavior of pigment−pigment and pigment−protein interactions. The description of energy transfer, in particular multichromophoric antenna structures, is shown to vary depending on the spatial and energetic landscape, which dictates the relative coupling strength between constituent pigment molecules. In the latter half...
01 Jan 1975-
01 Oct 2014-Current Opinion in Colloid and Interface Science
Abstract: Tailor-made microparticles and nanoparticles are finding increasing use in food products to alter their nutritional characteristics, flavor profile, appearance, rheology, stability, and processability. These particles are often fabricated from food-grade biopolymers, such as proteins and polysaccharides. Food biopolymers display a diverse range of molecular and physicochemical properties (e.g. molecular weight, charge, branching, flexibility, polarity, and solubility) which enables the assembly of colloidal particles that exhibit a broad range of functional attributes. By careful selection of appropriate biopolymers and assembly methods, biopolymer particles can be fabricated with tailored behaviors or features. In this article, we review recent developments in the design and fabrication of functional biopolymer nanoparticles and microparticles, and highlight some of the challenges that will be the focus of future research.
Author's H-index: 23