There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

Nature And Properties Of Soils

Elements Of X Ray Diffraction

In recent years, natural fibers reinforced composites have received much attention because of their lightweight, nonabrasive, combustible, nontoxic, low cost and biodegradable properties. Among the various natural fibers; flax, bamboo, sisal, hemp, ramie, jute, and wood fibers are of particular interest. A lot of research work has been performed all over the world on the use of natural fibers as a reinforcing material for the preparation of various types of composites. However, lack of good interfacial adhesion, low melting point, and poor resistance towards moisture make the use of natural fiber reinforced composites less attractive. Pretreatments of the natural fiber can clean the fiber surface, chemically modify the surface, stop the moisture absorption process, and increase the surface roughness. Among the various pretreatment techniques, graft copolymerization and plasma treatment are the best methods for surface modification of natural fibers. Graft copolymers of natural fibers with vinyl monomers provide better adhesion between matrix and fiber. In the present article, the use of pretreated natural fibers in polymer matrix-based composites has been reviewed. Effect of surface modification of natural fibers on the properties of fibers and fiber reinforced polymer composites has also been discussed. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers

Pretreatments of Natural Fibers and their Application as Reinforcing Material in Polymer Composites—A Review

In materials science, “green” synthesis has gained extensive attention as a reliable, sustainable, and eco-friendly protocol for synthesizing a wide range of materials/nanomaterials including
 metal/metal oxides nanomaterials, hybrid materials, and bioinspired materials. As such, green synthesis is regarded as an important tool to reduce the destructive effects associated with the traditional methods of synthesis for nanoparticles commonly utilized in laboratory and industry. In this review, we summarized the fundamental processes and mechanisms of “green” synthesis approaches, especially for metal and metal oxide [e.g., gold (Au), silver (Ag), copper oxide (CuO), and zinc oxide (ZnO)] nanoparticles using natural extracts. Importantly, we explored the role of biological components, essential phytochemicals (e.g., flavonoids, alkaloids, terpenoids, amides, and aldehydes) as reducing agents and solvent systems. The stability/toxicity of nanoparticles and the associated surface engineering techniques for achieving biocompatibility are also discussed. Finally, we covered applications of such synthesized products to environmental remediation in terms of antimicrobial activity, catalytic activity, removal of pollutants dyes, and heavy metal ion sensing.

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‘Green’ synthesis of metals and their oxide nanoparticles: applications for environmental remediation

In this paper, psyllium (Psy) and acrylamide (AAm) based superabsorbent, synthesized using potassium persulphate (KPS) as an initiator and hexamethylene tetramine (HTMA) as a crosslinker, has been investigated for its swelling behaviour in distilled water as a function of time, temperature and pH. The hydrogel has further been applied for controlled delivery of 5-amino salicylic acid (5-ASA) under different pH conditions at 37 oC. It has been found to show Fickian type mechanism as the drug release showed diffusion coefficient less than 0.50 for all the pH conditions.The gel characteristic constant has been found to show 6.9 × 10 -2 , 20.61 × 10 -2 and 33.4 × 10 -2 values for pH 4.0, 7.0 and 9.2, respectively. The initial diffusion coefficient has been found to show greater values than late diffusion coefficient confirming greater release at the early stages of the drug release than that in the late stages. keywords: psyllium, acrylamide, 5-amino salicylic acid, drug delivery, superabsorbent

/pdf/utilization-of-acrylamide-and-natural-polysaccharide-based-5yu7iknwxl.pdf

Utilization of acrylamide and natural polysaccharide based polymeric networks in ph controlled release of 5-amino salicylic acid

The main objective of this research work is to synthesize crosslinked hydrogel from xanthan gum and acrylamide under the influence of microwave radiations by graft polymerization technique in prese...

Rapid Synthesis of Acrylamide onto Xanthan Gum Based Hydrogels under Microwave Radiations for Enhanced Thermal and Chemical Modifications

Guar gum-poly(acrylic acid-aniline) based interpenetrating network hydrogels were prepared via two-step aqueous polymerization in which aniline monomer was in situ polymerized to induce electrical conductivity. The hydrogels were characterized by FTIR, TGA and SEM techniques. Biodegradation of synthesized hydrogels was performed in soil burial and composting conditions. Synthesized hydrogel was evaluated as an adsorbent to remove cationic dye [methylene blue (MB)] from aqueous solution. The contact time, adsorbent dosage, pH and temperature were optimized for maximum adsorption. The kinetics of MB adsorption was analyzed using the pseudo first order and pseudo second order models. Pseudo second order kinetic model represents better experimental data than the pseudo first order model, which indicates that adsorption system fits into second order kinetics model.

Synthesis of guar gum-acrylic acid graft copolymers based biodegradable adsorbents for cationic dye removal

Bifunctional gelatin/dextrin hybrid backbone based fluorescent chemo-sensor for the detection of tannic acid and removal of eosin yellow dye

Psyllium, a medicinally important natural polymer was functionalized with acrylic acid using FAS-H2O2 as redox initiator and glutaraldehyde as a crosslinker. Synthesized hydrogel was characterized with FTIR spectroscopy, SEM and TGA/DTA techniques to know their surface morphology and thermal stability. Salt resistant swelling behavior of synthesized hydrogel was studied in different salt solutions as a function of concentration of salt, temperature and pH. It was found that synthesized hydrogel showed maximum swelling (514.0 %) in NaCl solution followed by NH4Cl, MgCl 2 , CaCl 2 and BaCl 2 solution. Psy-g- poly(AA) hydrogel showed maximum swelling (863.49%) at 30 oC in distilled water. Copyright © 2010 VBRI press.

Balbir Singh Kaith

Papers

Utilization of acrylamide and natural polysaccharide based polymeric networks in ph controlled release of 5-amino salicylic acid

Rapid Synthesis of Acrylamide onto Xanthan Gum Based Hydrogels under Microwave Radiations for Enhanced Thermal and Chemical Modifications

Synthesis of guar gum-acrylic acid graft copolymers based biodegradable adsorbents for cationic dye removal

Bifunctional gelatin/dextrin hybrid backbone based fluorescent chemo-sensor for the detection of tannic acid and removal of eosin yellow dye

Synthesis, characterization and salt resistance swelling behavior of psy-g-poly(AA) hydrogel