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We focus on the conductivity analysis of Aurivillius family of six-layered intergrowth compound, namely Bi7Ti4NbO21. The compound was prepared by solid state intergrowth route. The product compound belongs to orthorhombic structure and the lattice parameters were found to be: (a = 5.442 A0, b = 5.404 A0, c = 57.990 A0). The frequency dependent impedance measurements were made on the sample over a frequency range of 100 - 1MHz, right from room temperature to 500°C. A detailed study on ac-conductivity and complex impedance analysis was carried out on the said above intergrowth compound. The depressed and asymmetric semicircles of Cole-Cole plots suggest that the charge carriers are of non-Debye (multiple) type. The charge carriers were found to be controlled by thermally-activated process. Temperature dependent ac-conductivity data show change of slopes in the vicinity of intermediate and higher frequency domain. Finally, results were corroborated to the dielectric and FTIR data. [ABSTRACT FROM AUTHOR]

The title compound, C16H13FN4O2S, crystallizes in triclinic space group P1 with two molecules in the asymmetric unit. The 2-fluoro phenyl ring at chiral carbon C5 is positioned axially and bisects the pyrimidine ring with a dihedral angle of 83.407 (2)°. The pyrimidine ring adopts a flattened half-chair conformation in each molecule. There is positional disorder in the crystal, which has been overcome crystallographically and the structure is solved unambiguously. The fluorine atom at theortho position of the benzene ring is disordered over two sites in a 0.576 (5):0.424 (5) ratio. In the crystal, the molecular structure is stabilized by intermolecular N—H···N and C—H···O interactions. In addition, weak π···π stacking interactions with a centroid-centroid distance of 3.455 (6) Å is also observed. [ABSTRACT FROM AUTHOR]

Aluminium metal matrix composites with TiB2 ceramic reinforcements are extensively used in air vehicles, automobile, under sea applications due to their low weight to strength ratio, better corrosive properties, excellent wear resistant properties. In-situ composites are manufactured under flux assisted synthesis is cheapest, easy to fabricate and uniform distribution of ceramic particles. AA6061 is chemically react with halide salts like K2TiF6 and KBF4 to form TiB2 in aluminium matrix, because of exothermic reaction fine particles of TiB2 phases are formed at a optimum holding time (18min) of molten composite. Composite is prepared with different weight fractions like 0%,2.5%,5%,7.5% TiB2 in aluminium matrix. The TiB2 reinforcement and distribution are examined using SEM, XRD, EDAX analysis. Mechanical, Wear properties are studied and analyzed at different reinforcements of TiB2 Particulates, as increasing TiB2 content improves ultimate tensile strength, hardness, and wear resistance with decreasing ductility. [ABSTRACT FROM AUTHOR]

In the present work, experimental investigation has been carried out on 4-stroke petrol engine by using normal piston and modified piston. Swirl of air-fuel mixing is an important part in achieving the better combustion inside engine cylinder; to get this we have modified the piston design with 3 different configurations. The fuel chosen here is a mixture of ethanol and petrol to facilitate the combustion process in different proportions. The results show that it has given better result for single grooved hemispherical piston when compared to unmodified piston. [ABSTRACT FROM AUTHOR]

The effect of sliding load and velocity on sliding wear behavior of PTFE filled PA66/PA6 blend thermoplastic composites is studied. The blend PA66/PA6 in 80/20 wt. % was selected as the base material and 10 wt. % PTFE as filler for the composites. These thermoplastic composites were produced by melt mix method using extrusion technique followed by injection molding. ASTM G99 method has been adopted to study the sliding wear behavior under the influence of different loads (25, 50, 75 and 100 N) and velocities (0.5, 1, 1.5 and 2 m/s). The results revealed that the straight chain polymer PTFE proved to be the best tribological agent for sliding wear applications. The tribological response has been studied using wear volume loss and specific wear rate. It is observed that addition of PTFE in to the blend deteriorates the volumetric loss of blend composites. The specific wear rate increases with increase in sliding velocity. The plastic deformation due to higher sliding velocity is most severe on wear volume loss. The sliding velocity is most sensitive tribological response than sliding load. It is observed that solubility parameter of PTFE and formation of polymer transfer film on the steel counter face defines the wear volume loss. The SEM images show that severe plastic deformation and matrix melting were the failure mechanisms. [ABSTRACT FROM AUTHOR]

Micron size U-type barium hexaferrite powder have been synthesized by solid state reaction process. Powder X-ray diffractometer technique has been used to confirm the phase of hexagonal through the calculate lattice parameters. Field emission scanning electron microscope was used to morphology of synthesized powder and prepared composites. Complex permittivity, complex permeability and absorbing properties have been studied for all polymeric composites by using the Agilent vector network analyzer in the frequency range of 2-18 GHz. The minimum RL was observed as -32.38dB for the absorber with thickness of 3.6mm. [ABSTRACT FROM AUTHOR]

Considerably improved fracture resistance can be introduced to monolithic materials or even to the composites by introducing carbon fibers and carbon nanotubes (CNTs) as hybrid reinforcements. The present study describes the influence of amino functionalized multi walled CNTs (AMWCNTs) addition on the fracture behaviour of carbon fiber reinforced hybrid composite and neat epoxy matrix. AMWCNTs are introduced in thermosetting epoxy resin and then carbon fibers are reinforced in the matrix. A fixed quantity (0.5 weight %) of AMWCNTs are dispersed in the epoxy matrix. Amino functionalized MWCNTs were used for homogenous dispersion and synthesized by probe type sonicator. Fractograhic studies were carried out to know the distribution of AMWCNTs in epoxy matrix. The introduction of AMWCNTs in epoxy matrix significantly increases the overall fracture energy. It is speculated that AMWCNTs due to their large aspect ratio have a significant toughening effect since extra energy is needed in order to pull them out from the polymer epoxy matrix and start the crack propagation following a kinking out pattern at nanoscale. [ABSTRACT FROM AUTHOR]

Friction and wear have considerable role in the life span of two interacting parts.Incorporation of nanofillers in polymers/elastomers matrix causes commendable changes in its tribologicalproperties. The main purpose of this work is to reduce the coefficient of friction and wear rate of Acrylo Nitrile Butadiene rubber (NBR).To achieve such objective traditionally well knownlubricants graphite(G),tungsten disulphide(WS2) and there hybrid combination was incorporated in NBR matrix. Effect of applied load (force) and concentration of fillers on tribological properties of NBR had been studied.The filler incorporation enhanced the hardnessby 8%, showed resistance to hydraulic oil and aging effect also got improved significantly. A particular optimized concentration of NBR with hybrid combination of 2% WS2 and 4% Graphite showed minimum coefficient of friction as well as wear rate. A hypothesis could be attributed that similar lamellar structure of WS2and Graphite along with formation of a stable nanoscale disulfide tribofilmcould result in lowering of friction.These substantially improved properties of nanoreinforced rubber materials would definitely pave promising path for plethora of potential technological applications. [ABSTRACT FROM AUTHOR]

Chloroaluminum phthalocyanine (ClAlPc) synthesized by adopting focused microwave synthesis approach was doped with nanocrystalline TiO2 (5% by weight) and developed into the thin film sandwiched device having ITO/ClAlPc:TiO2/Ag Schottky configuration by spin coating technique covering 1 cm2 as an active area. The so fabricated device having initial dark current of the order of 0.2 5 m A was exposed to variable dose of gamma radiation ranging from lcGy to 10 Gy at a dose rate of 1 Gy/hour. The experimental observation reveals the generation of localized traps leading to structural disorder within the solid material. Doping with TiO2 enhances the surface area of the film which in tern improves sensitivity of device to wider dose rage. Exposure of the device to variable dose of gamma radiation imparts decrease in forward bias current and capacitance characteristics with increase in radiation dose. Also, absorbance characteristics of the Al Pc: TiO2 was analyzed before & after exposure to radiation which reveals that absorbance decreases with radiation dose leading to decrease in optical band gap. [ABSTRACT FROM AUTHOR]

The neutron-rich nuclei 72Ni and 72Cu have been produced in the proton-induced fission of 238U at the LISOL and ISOLDE facilities of Louvain-La-Neuve and CERN. Partial β-decay schemes are presented, giving some information about the nuclear structure of their daughter nuclei 72Cu and 72Zn. The lifetime of 72Cu was determined to be T1/2 = 6.63(3) s, in line with previous measurements. No β-decaying isomeric states were identified in 72Cu, in contrast to 70Cu. The spin and the parity of several states in 72Cu are tentatively assigned and a comparison is made with different shell-model predictions. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

Novel ceramics of Bi3.25La0.75Ti3-xZrxO12(x = 0.1,0.3,0.5,0.7&1) were prepared by solid state route. X-ray diffraction analysis indicate formation of single phase layered-perovskite with pseudo-orthorhombic structure. Ti-O stretching mode was observed in FTIR data. Dielectric and impedance measurements were also made on the ceramics. [ABSTRACT FROM AUTHOR]

Chloroaluminum phthalocyanine (ClAlPc) synthesized by adopting focused microwave synthesis approach was doped with nanocrystalline TiO2 (5% by weight) and developed into the thin film sandwiched device having ITO/ClAlPc:TiO2/Ag Schottky configuration by spin coating technique covering 1 cm2 as an active area. The so fabricated device having initial dark current of the order of 0.2 5 m A was exposed to variable dose of gamma radiation ranging from lcGy to 10 Gy at a dose rate of 1 Gy/hour. The experimental observation reveals the generation of localized traps leading to structural disorder within the solid material. Doping with TiO2 enhances the surface area of the film which in tern improves sensitivity of device to wider dose rage. Exposure of the device to variable dose of gamma radiation imparts decrease in forward bias current and capacitance characteristics with increase in radiation dose. Also, absorbance characteristics of the Al Pc: TiO2 was analyzed before & after exposure to radiation which reveals that absorbance decreases with radiation dose leading to decrease in optical band gap. [ABSTRACT FROM AUTHOR]