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The research work aims to analyze the effect of graphene oxide (GO) distribution on the morphological, physical, static and dynamic mechanical properties of polyolefin matrices. Polar polymer namely maleic anhydride grafted polyethylene (MA-g-PE) is used as a compatilizer to incorporate GO into low density polyethylene (LDPE). Preparation of polyolefin nanocomposite is carried out by melt-mixing technique. According to ASTM standard, the specimens are prepared through compression molding technique. Mechanical properties of pure and graphene oxide filled polymers are analyzed through universal testing machine. Storage modulus and tan delta characteristics are analyzed through dynamic mechanical analyzer. A series of characterization methods like the X-ray diffraction (XRD), Fourier transform-infrared spectroscopy (FT-IR), scanning electron microscope (SEM) and transmission electron microscopic (TEM) were performed on the prepared nanocomposites. The effects of compatibilizer and grapheme oxide on polyolefin nanocomposites were investigated by dynamic mechanical analysis (DMA), tensile test and percentage elongation. The XRD results showed increase in intergallery spacing of nanosheets proving the formation of GO from flake graphite. TEM images prove the improved distribution of GO sheets into the polymer matrix in presence of compatibilizer. Compatiblized nanocomposites show significant enhancement in Tensile strength, modulus of elasticity, storage modulus and subsequent decrease in tan delta peak implying minimum heat buildup compared to control. Polar-polar interaction between GO and compatibilizer leads to improved distribution of the nanofiller in the base polymer matrices. This indeed enhances the technical properties of the polymer.

Novel hetero structured arrays of CdTe quantum dots capped ZnO nanostructures were successfully prepared through a three tier process. C-axis oriented ZnO nanostructures, namely ZnO nanox (where, x = discs, rods and wires), were prepared on glass and ITO substrates by employing simple, template free and low temperature solvothermal methods. CdTe quantum dots were synthesized subsequently through an organometallic route. ITO/ZnO NanoX/CdTe heterostructured arrays were finally developed, by capping ZnO nanostructured arrays with CdTe quantum dots by using 3-mercaptopropionic acid. The crystalline, structural, morphological and optical features of the individual nanostructures and the heterostructured arrays were investigated by using XRD, HR-TEM, SEM, EDAX, AFM, UV and PL. The role of solvents, solution concentration and temperature on deciding the final morphologies in solvothermal syntheses were studied and the possible growth mechanism of the different nanostructure arrays were proposed. The comparative electron transport studies of the ITO/ZnO NanoX/CdTe heterostructure arrays were carried out. Electrochromic display units having fast electron transport capabilities were developed. The study put forth many futuristic applications of these hetero structured assemblies in wide spectrum of scientific and industrial disciplines, particularly in the areas where a fast electron transport is required. Keywords: ZnO, CdTe, Heterostructured arrays, Solvothermal synthesis, Electron transport, Electrochromism

A group of muscle diseasesresulting in the increasing weakening and the breakdown ofskeletal muscles over time is called as muscular dystrophy. The disorders differ in parameters like which muscles are primarily affected, the degree of weakness of bones, how fast they become worse, and when the symptoms for this disorder begin. Many people will become unable to walk eventually. There are more than thirty specific typesof muscular dystrophy undernine main categories. The most common type among these is Duchenne muscular dystrophy (DMD). This is caused primarily due to the lack of a protein called Dystrophin and it is found in muscle fibre membrane of our body. Currently, there being no cure for it, somephysical, occupational, orthotic intervention (e.g., ankle-foot orthosis), speech, and respiratory therapies may tend in being helpful in terms of management. Being human they also love to travel alone and interested in satisfying their own needs which shows they need to live as a common man/woman than living in a situation where some people always crowd or assist around them in satisfying their needs. So, we decided to break the rules and allow them to move anywhere around their place and use the toilet during a nature call without anyone’s support by integrating the lifting mechanisms and the toilet provision in the wheel chair.

Hierarchically porous alumino-siloxane aerogels (ALS-PG) with a rare structural architecture were developed through a biotemplating method using pollen grains of Hibiscus rosa-sinensis. The unique structure of the Hibiscus rosa-sinensis pollen makes it an attractive biotemplate, by replicating all levels of macro- and mesoscale morphological features. The micromorphological analysis exposed funnel-shaped macrochannels between the mesoporous aerogel framework that are difficult to design artificially. The N2 sorption analyses confirmed hierarchical trimodal pore size distribution with an average mesopores diameter (ca. 3.9, 8.7, 26.6 nm), high BET/Langmuir surface area (497/664 m2 g–1) and large pore volume (1.6788 cm3 g–1) than the corresponding nontemplated aerogels and xerogels counterpart. Beneficial properties of this sophisticated hierarchical porous structure was examined and confirmed by the immobilization of steapsin lipase. Hierarchically porous ALS-PG showed enhanced loading and immobilization e...

‘Nanocoolants’ offering extraordinary heat transport property demand new and exotic nanostructures as fillers that can display enhanced thermal conductivity and thermochemical stability for efficient thermal management operations. Herein we report for the first time, the processing of stable MAXene nanofluids using 2D MAXene nanosheets derived from the bulk nanolaminated Ti 3 SiC 2 MAX phase ternary carbides via shear induced micromechanical delamination technique. The beneficial multifunctional physical properties of MAXene colloid such as thermal conductivity, viscosity and lubrication effect are assessed and reported. An enhancement of thermal conductivity by ∼45% is achieved at 323 K with a loading of 0.25 Vol% MAXene nanosheets. Interestingly, MAXene nanofluids exhibit decreased viscosity than the basefluid revealing that it can act as ‘rheo-controlled’ nanofluid. It is a unique rheological behavior, not exist in many well established conventional ceramic nanofluids. In addition, MAXene nanofluids also offer lubricating property with very low coefficient of friction (COF) values (

A 2-dimensional ceramic nanostructure was successfully processed out of nanolamellar 312 MAX phase ternary carbide, titanium silicon carbide, Ti3SiC2 (TSC), via a simple shear-induced delamination technique. It has been explored as a functional nanofiller for obtaining chemically homogeneous, low-friction, self-lubricating epoxy nanocomposites. The structural characterization of the MAX phase Carbide Derived Ceramic Nanostructure (CDCN) was carried out using Dynamic Light Scattering (DLS), Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) analysis. Subsequently, CDCN was mixed with Araldite CY 225 (DGEBA) at different percentages and thermally cured using Aradur HY 925 hardener at 130 °C to make epoxy–Ti3SiC2 nanocomposites. The effect of CDCN-nanofiller was studied on epoxy rheology, glass transition temperature (Tg), thermal stability, flexural and compressive strengths, microhardness, dry sliding wear and friction properties. It was found that, unlike other ceramic fillers, CDCN chemically interacts with epoxy and readily dispersed in a polymer matrix without any deleterious structural defects. It resulted in the formation of physico-chemically homogeneous microstructures. Epoxy composites prepared with CDCN filler attained 50% more mechanical strength and hardness. Wear analysis trends indicate Ti3SiC2 nano reinforcement possibly formed a lubricating tribo-chemical film that decreases the wear rate and coefficient of friction. This work is significant in such a way that a novel nanofiller has been identified from MAX phase carbide family which offers a self-lubricating interface and produces mechanically reliable, damage tolerant epoxy composite for state-of-the-art engineering applications.

Herein, we report the synthesis of ultrathin 2D Ti3SiC2 (MAXene) nanosheets via a facile shear induced micromechanical cleavage strategy. The very high dispersion stability, the UV absorption properties, high electrical conductivity and castability into thin films make the newly derived Ti3SiC2 nanosheets an ideal candidate for many functional applications.

Surface functionalized multiwall carbon nanotube (MWCNT) reinforced teflon fibrils (MWCNT@Teflon) were successfully tested as an - oil - absorbent that can be used as a potential oil recovery material at the time of oil spill accidents in water. We found that oleic acid functionalization of MWCNTs was important for their adhesion onto teflon fibrils and at the same time prevented the MWCNT leaching into oil/water interface. The fibrils had displayed superior mechanical and thermal stability and provided a new insight to oil spill clean-up applications with easy recovery of absorbed oil by simple squeezing. Recycling of exhausted MWCNT@Teflon fibrils after oil recovery applications was conducted by pyrolysis under inert atmosphere in presence of magnetic clay. The magnetic clay absorbed the pyrolysis products, resulting in a heterostructured magnetic clay carbon composite (MCC) which was found super paramagnetic and chemically stable in all pH. The MCC was found capable of adsorbing textile dye from water ultra-fast with in a maximum contact time of 2 min and magnetically separable after adsorption experiments.

Thermal, mechanical and tribological properties of a new ceramic–polymer nanocomposite in which polyaryletherketone (PAEK) polymer was reinforced with titanium silicon carbide (Ti3SiC2), a ceramic nanolaminate belonging to the MAX phase family (M is an early transition metal, A represents group IIIA or IVA element and X is either carbon and/or nitrogen) are reported for the first time. PAEK–Ti3SiC2 nanocomposites with varying volume fractions of Ti3SiC2 were processed by hot pressing. The effect of Ti3SiC2 on the thermal expansion, bulk hardness, mechanical strength, wear and friction properties was systematically analyzed and the results are discussed. The study confirms that the Ti3SiC2 controlled the high thermal expansion property of PAEK polymer. In addition to that, it enhanced the wear resistance and mechanical strength of PAEK without affecting its inherent low-friction characteristics.

Monazite type rare earth phosphates (REPs) are low thermal conducting (

Non Linear ceramic Resistor (NLR) was processed using ZnO-La2O3 rare earth composition via combustion technique involving urea and glycine as organic fuels. The La2O3 NLR ceramic was sintered at 1300 °C/ 3 h that showed dense microstructures with average grain size of 1 μm. The current v/s voltage characteristics of La2O3 NLR were compared among the fuels. In addition to that the combustion chemistry of urea and glycine was monitored via C-H-N-S analysis and the functional property was assessed by UV-Vis analysis. The I-V analysis confirmed that the La2O3 NLR ceramic prepared with urea fuels exhibits only a linear resistor behavior whereas an excellent non-ohmic nature was obtained in glycine fuels. The grain-grain boundary property was further examined by impedance analysis. The study brought out a promising, eco-friendly rare earth composition for obtaining high-energy NLR ceramics.

The present chapter deals with a systematic report on ‘sol-gel ZnO varistors’, an area which needs to be much explored in terms of the applications it holds. The book chapter starts with a brief introduction on varistors. Subsequently, a detailed description on the so far adopted conventional preparation methods and chemical synthesis strategies for varistors are presented. Among the many chemical methods, the advantages of employing a sol-gel method for varistor technology are discussed in detail in later sections. A detailed literature survey on the preparation, properties and advantages of sol-gel derived ZnO varistors is provided. The main focus of the study is to highlight the importance of nanoinclusions for high-performance varistors in terms of controlled grain size, improved grain boundary area and homogeneous dopant distribution at the grain boundaries. The chapter concludes with a discussion on the recent research interests on the sol-gel ceramic–polymer varistors and studies on varistor-epoxy, ZnO-PANI, ZnO-PANI-PVA, GaAs-PANI-PE, Si–Polymer varistor composites.

Nano size ZnO–Bi2O3 varistor precursor powders containing Y2O3 and Pr6O11 rare earth dopants were prepared by low temperature refluxing at 80 °C. Effect of rare earth dopants, densification by two-step sintering, evolution of microstructures and their influence on varistor properties were investigated. Chemically synthesized nano- precursor varistor powders produced controlled grain size in two-step sintering in which the average sintered ZnO grain size was reduced to at least half compared to the conventionally processed ZnO–Bi2O3 varistors. The study revealed that such grain size reduction is highly beneficial to attain enhanced varistor properties.

Physico-chemical transformations of ZnO have been investigated in low temperature reflux reactions involving zinc nitrate, hexamethylene tetramine and cetyl trimethyl ammonium bromide. The stability features of various ZnO micro/nano structures were systematically examined from 4 to 60 h. The study showed the formation and transformation of multidimensional ZnO structures such as multipods, microtubes, microplates, nanoplates, nanoflowers, nanoblades and diffused nano networked structures including single crystalline nanoplates in a simple reflux synthesis. The crystalline nature, phase purity, associated structural features and surface characteristics were studied using powder X-ray, Raman, SEM, TEM, AFM, FT-IR, XPS and TG analytical techniques and the results were discussed. The kinetics involved in the evolution of ZnO structures and % yield of the ZnO products has also been studied and a possible growth mechanism is proposed on the basis of time-triggered transformations. The inherent anisotropic nature of ZnO as well as the change in chemical environment over the time of reflux is found to control the growth and evolution of diverse ZnO morphologies.

Biopolymer-mediated sonochemical synthesis has been carried out for obtaining stable, nanocrystalline ZnO-biopolymer nanocomposite colloids to be applied on polymer foam and cotton fabrics to ultimately produce multifunctional, heath-care surface modifications. In situ nucleation and growth of nano-ZnO was achieved by ultrasonication at ∼ 60°C in aqueous biopolymer media prepared using starch, gelatin, chitosan, and agar. Phase analysis, structure–bonding characteristics, ZnO morphology, particle size distributions, rheology, and thermal decompositions were studied using XRD, FTIR, SEM/TEM, viscometer, and TG/DTA tools. Morphologically varied nanocrystalline ZnO of size ∼ 40 nm were synthesized. Biopolymers media resulted in stable ZnO colloids through steric stabilization. ZnO-biopolymer nanocomposites colloid was applied on polyurethane foams and cotton fabric substrates by dip coating. These coatings were examined for the UV photoactivity and resistance to fungi growth. A comparison has been made among the biopolymers. It is shown that the surface coatings of ZnO-biopolymer nanocomposites can produce anti-fungal, UV active polymer foams and fabrics. The study has significant relevance in automobile and hospital industries because such functionally modified polymer foams and cotton fabrics can be disinfected and refreshed just by periodic application of water-free, UV cleaning. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

In today’s environment the storage of fuels in onboard vehicle, underground and above ground storage are of great challenge due to its surface temperature, evaporation loss and corrosiveness. In summer, due to solar radiation, which has an intensity of 1.373 kW/m2 at the earth’s atmosphere surface, causes the surface temperature of oil storage tanks to rise.

International audience; The influence of SiO2 doping on the microstructure and electrical behavior of SnO2 varistors has been studied. The varistor effect was studied over a wide range from 10 9 A to 104 A. It is shown that the J(E) characteristic of SnO2 ceramics exhibits a nonlinear coefficient>100. The SiO2 doping also resulted in a sharp-abrupt upturn region in the I-V characteristic, indicating a single semiconductor junction behavior. The leakage current of the varistors is rather low, on the order of 10 10 S m 1. In the upturn region of operation where the curve departs from the nonlinear relation and approaches the value of the bulk resistivity of the material, the ceramic is characterized by a current density almost independent of the applied voltage. A very small amount of SiO2 causes large perturbations of the conventional thermionic emission observed in varistor ceramic materials.

In modern solid waste landfills, liner systems are essential structural elements that ensure that waste materials are safely separated from the environment. Many liner systems have been developed and used over the past decade. Among impermeable layers, clay liners are regarded as one of the very significant components of liner system and are being used worldwide as a waste containment system in landfills. One of the failures associated with clay liners is the occurrence of nonuniform settlements, resulting from the sudden collapse of waste, or the decomposition of waste materials, and (or) the subgrade over which the liner is laid. This paper deals with the use of a small centrifuge to model the deformation behaviour of clay liners. Model tests were performed in a small geotechnical centrifuge to investigate the behaviour of clay liners in landfills subjected to nonuniform settlements at sharp curvatures. A parametric study was conducted to analyze the influence of parameters like thickness, consistency, and overburden on the behaviour of clay liners. The clay liner without any overburden is observed to experience severe cracking in the form of deep and wide cracks at the maximum curvature zone. The depth and width of the cracks are found to decrease with an increase in clay liner thickness. The cracking failure pattern is suppressed by shearing for a clay liner with an increase in overburden pressure. Based on model test results, the clay liner with an adequate overburden is found to be free from cracking failure even when subjected to sharp curvatures. The effective usage of a small geotechnical centrifuge to model the deformation behaviour of clay liners is demonstrated adequately.Key words: landfills, municipal solid waste, clay liners, centrifuge modeling, nonuniform settlements, model tests.

The present work encompasses the strategic design, synthesis and development of high energy field ZnO varistors. The key aspect of the study involves the chemical synthesis of ZnO based nanorod nanofillers by a pH selective precipitation and reflux method. High field varistors were developed out of these crystalline nanofillers by employing them as fillers to the micron sized commercial varistor powder. A systematic investigation of the microstructural changes of the nanofiller added varistor samples were carried out under step-sintering and the normal sintering conditions. Comparative studies were also performed with the nano and micro counterparts. The influence of nanofillers in the varistor powder packing, grain structure refinement, grain size reduction and on the I–V properties were analyzed under the step-sintering conditions. Based on the performance analysis, the current study foresees ample opportunities for miniaturizing varistors with at least half the size of currently available varistors.