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Search Results: 1 - 10 of 10076 matches for " properties "
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Acoustic Wave Propagation in Nanocrystalline RuCo Alloys  [PDF]
Pramod Kumar Yadawa, Devraj Singh, Dharmendra Kumar Pandey, Giridhar Mishra, RajaRam Yadav
Advances in Materials Physics and Chemistry (AMPC) , 2011, DOI: 10.4236/ampc.2011.12003
Abstract: The ultrasonic properties like elastic constant, ultrasonic velocity in the hexagonal structured nanocrystalline RuCo alloys have been studied along unique axis at room temperature. The second and third order elastic constants (SOEC & TOEC) have been calculated for these alloys using Lennard-Jones potential. The orientation dependent ultrasonic velocity has been also evaluated to study the anisotropic behaviour of these alloys. The velocities VL and VS1 have minima and maxima, respectively at 45° with unique axis of the crystal, while VS2 increases with the angle from unique axis. The inconsistent behaviour of angle-dependent velocities is associated to the action of second order elastic constants. Debye average ultrasonic velocities of these alloys are increasing with the angle and has maximum at 55° with unique axis at room temperature. Hence, when a ultrasonic wave travels at 55° with unique axis of these alloys, then the average ultrasonic velocity is found to be maximum. Elastic constants and density are mainly the affecting factor for anomalous behaviour of ultrasonic velocity in these alloys. The mechanical and ultrasonic properties of Co0.75Ru0.25 alloy will be better than the other compounds due to their high SOEC, ultrasonic velocity and low ultrasonic attenuation. Co0.75Ru0.25 alloy is more suitable for industrial and other uses, as it has the highest elastic constants and lowest ultrasonic attenuation in comparison to other of these alloys. The results of this investigation are discussed in correlation with other known thermophysical properties.
Effect Of Flyash On The Mechanical, Thermal, Dielectric,Rheological And Morphological Properties Of Filled Nylon 6  [PDF]
Suryasarathi Bose, P.A. Mahanwar
Journal of Minerals and Materials Characterization and Engineering (JMMCE) , 2004, DOI: 10.4236/jmmce.2004.32007
Abstract: Fillers are used along with various commodities as well as engineering polymers to improve the properties of polymers. The performance of filled polymers is generally determined on the basis of the interface attraction of filler and polymers. Fillers of widely varying particle size and surface characteristics are responsive to the interfacial interactions with polymers. The present study deals with the effect of particle size and its concentration on the properties of flyash filled nylon 6.
Synthesis and Characterization of Co3O4 Thin Film  [PDF]
Vikas Patil, Pradeep Joshi, Manik Chougule, Shashwati Sen
Soft Nanoscience Letters (SNL) , 2012, DOI: 10.4236/snl.2012.21001
Abstract: Nanosized Co3O4 thin films were prepared on glass substrates by using sol-gel spin coating technique. The effect of annealing temperature (400°C - 700°C) on structural, morphological, electrical and optical properties of Co3O4 thin films were studied by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Electrical conductivity and UV-visible Spectroscopy (UV-Vis). XRD measurements show that all the films are nanocrystallized in the cubic spinel structure and present a random orientation. Six prominent peaks, corresponding to the (111) phase (2θ ≈ 18.90°), (220) phase (2θ ≈ 31.29°), (311) phase (2θ ≈ 36.81°), (222) phase (2θ ≈ 38.54°), (400) phase (2θ ≈ 44.80°), (511) phase (2θ ≈ 59.37°) and (440) phase (2θ ≈ 65.27°) appear on the diffractograms. The crystallite size increases with increasing annealing temperature. These modifications influence the optical properties. The morphology of the sol gel derived Co3O4 shows nanocrystalline grains with some overgrown clusters and it varies with annealing temperature. The optical band gap has been determined from the absorption coefficient. We found that the optical band gap energy decreases from 2.58 eV to 2.07 eV with increasing annealing temperature between 400°C - 700°C. These mean that the optical quality of Co3O4 films is improved by annealing. The dc electrical conductivity of Co3O4 thin films were increased from 10–4 to 10–2.cm)–1 with increase in annealing temperature. The electron carrier concentration (n) and mobility (μ) of Co3O4 films annealed at 400°C - 700°C were estimated to be of the order of 2.4 to 4.5 × 1019 cm–3 and 5.2 to 7.0 × 10–5 cm2.V–1.s–1 respectively. It is observed that Co3O4 thin film annealing at 700°C after deposition provide a smooth and flat texture suited for optoelectronic applications.
Physical Properties of Some Stoichiometric Rare Earth Nitride Single Crystals  [PDF]
Peter Wachter
Advances in Materials Physics and Chemistry (AMPC) , 2015, DOI: 10.4236/ampc.2015.53013
Abstract: The preparation and definition of large (3 - 5 mm edge length) single crystals of ScN, GdN, TbN, HoN, YbN and CeN is described. The Hall effect and the electrical conductivity are found to be metallic. The optical reflectivity between 30 meV (sometimes 1 meV) and 13 eV has been measured and the dielectric functions have been obtained. A plasma edge in the infrared confirms the metallic character. In GdN, a shift of this plasma edge with temperature through the magnetic ordering temperature has been observed as a new effect. GdN is in low magnetic fields antiferromagnetic, but becomes ferromagnetic in larger fields. The band structure is discussed. The magnetic exchange interactions have been derived. HoN in the relevant crystal directions has a spontaneous magnetic moment, but no saturation in fields up to 10 T. CeN is intermediate valent and exhibits a Pauli paramagnetism. The specific heat is measured down to 0.3 K and an enhanced?γ value is observed.
Electrical, Thermal and Mechanical Properties of CNT Treated Prepreg CFRP Composites  [PDF]
Yelda Akcin, Sukru Karakaya, Omer Soykasap
Materials Sciences and Applications (MSA) , 2016, DOI: 10.4236/msa.2016.79041
Abstract: This study is part of Smart Intelligent Aircraft Structures (SARISTU) project, which aims considerable improvements in aircraft damage tolerance, electrical conductivity and weight reduction besides producibility in industrial scale. In this study, the effect of multiwalled carbon nanotube reinforcement on electrical, thermal and mechanical properties of T800/M21 carbon fibre reinforced plastic is studied experimentally. T800/M21 is a commercial prepreg carbon fibre/epoxy composite material considered for CNT treatment by means of CNT-doped thermoplastic-based dry powder. The CNTs are deposited on top of prepreg material uniformly using a controlled spraying machine selecting the best state-of-the art and innovative performing technology from the candidate technologies within the project. The electrical conductivity of the composite material with/without CNT is measured in longitudinal, transverse and thickness directions. The changes occurring in the electrical conductivity of the composite materials are investigated. In order to investigate thermal behaviour of the composite materials, differential scanning calorimetry and thermogravimetric analyses are performed. Detailed thermal analysis is conducted for with/without carbon nanotube reinforced material to obtain the thermal conductivity, specific heat and thermal expansion coefficient of the material. Finally, the effect of carbon nanotube reinforcement on mechanical behaviours is studied by tensile, bending and shear tests.
Effect of Combined Chemical Treatment on Physical, Mechanical and Chemical Properties of Posidonia Fiber  [PDF]
Saoussen Zannen, Lassaad Ghali, Mohamed Taher Halimi, Mohamed Ben Hassen
Advances in Materials Physics and Chemistry (AMPC) , 2016, DOI: 10.4236/ampc.2016.611027
The aim of this study is to investigate the effect of chemical treatment method on the properties of Posidonia fibers. The chemical treatment which is carried out is a combined hydrogen peroxide and sodium hydroxide treatment. First, an investigation of the treatment processes was undertaken. Secondly, the physical properties (linear density, diameter and ratio length per diameter), the mechanical properties (tenacity, elongation) and chemical properties (FT-IR spectra and X ray diffraction) of posidonia fibers were investigated. The optimum operating conditions were identified using a factorial design.
Effect of Ultrasound and Xylanase Treatment on the Physical-Mechanical Properties of Bleached Eucalyptus Kraft Pulp  [PDF]
Larisse A.R. Batalha, Juliana C. da Silva, Carolina M. Jardim, Rubens C. Oliveira, Jorge L. Colodette
Natural Resources (NR) , 2011, DOI: 10.4236/nr.2011.22017
Abstract: The modification on the fiber structure of bleached eucalyptus kraft pulp is a very attractive alternative for improve- ments in the properties of paper production. The enzymatic treatment by xylanases and ultrassonic treatments modify the characteristics of the fibers, has been reported. Therefore, the purpose of this study was to evaluate the influence of ultrasonic waves as a facilitator of the action of enzymes (hemicellulase) by modifying the physicochemical nature of fiber eucalyptus Kraft pulp, in order to improve the physical and mechanical properties of the paper. But it was observed the that idea of ultrasound acts as facilitator for action of enzymes can’t be affirmed, since in most properties XA-1 and XA-2 were equal statistically. It may be noted that the junction of ultrasound and xylanase provided improves on tensile index, specific elastic modulus and tensile energy absorption and a decrease of tear index on the mechanical properties of handsheet and it increased the opacity when the ultrasound was applied before xylanase.
Synthesis and Ultrasonic Characterization of Cu/PVP Nanoparticles-Polymer Suspensions  [PDF]
Giridhar Mishra, Satyendra Kumar Verma, Devraj Singh, Pramod Kumar Yadawa, Raja Ram Yadav
Open Journal of Acoustics (OJA) , 2011, DOI: 10.4236/oja.2011.11002
Abstract: A polymer colloidal solution having dispersed nanoparticles of Cu metal has been developed using a novel chemical method. Colloidal solutions of representative concentrations of 0.2 to 2.0 wt% Cu-nanoparticles con-tents in the primary solutions were prepared to study the modified ultrasonic attenuation and ultrasonic velocity in polyvinyl alcohol (PVP) polymer molecules on incorporating the Cu-nanoparticles. The synthesized copper metal nanoparticles dispersed in the polymer solutions were characterized by UV-Visible absorption spectros-copy, X-ray diffraction (XRD) and Transmission electron microscopy (TEM). The nanofluid sample showed a symmetrical peak at 592 nm due to the surface plasmon resonance of the copper nanoparticles. XRD results confirmed that copper nanoparticles were crystalline in the colloidal solution. The TEM micrograph revealed spherical copper nanoparticles having diameter in the range 10 - 40 nm. A characteristic behaviour of the ultra-sonic velocity and the attenuation are observed at the particular temperature/particle concentration. It reveals that the colloidal suspension occurs in divided groups in the small micelles. The results are discussed in correlation with the thermophysical properties predicting the enhanced thermal conductivity of the samples.
Microwave Sintering of Zn-Nb Doped Barium Hexaferrite Synthesized via Sol-Gel Method  [PDF]
Samikannu Kanagesan, Mansor Hashim, Sinnappan Jesurani, Thirunavukarasu Kalaivani, Ismayadi Ismail
Materials Sciences and Applications (MSA) , 2014, DOI: 10.4236/msa.2014.54021

A series of polycrystalline M-type hexagonal ferrites with the formula BaFe12-2xZnx NbxO19 (x = 0.2, 0.4, 0.6, 0.8 mol%) have been synthesized by the sol-gel method. The composition and microstructure govern the magnetic properties of ferrites. The XRD analysis shows the formation of pure magneto plumbite phase without any other impurity phases. The Zn-Nb substitutions in barium hexaferrite have been confirmed through magnetic measurements. The results show that the magnetic properties are closely related to the distributions of Zn-Nb ions on the five crystallographic sites. The saturation magnetization and coercivity increase with increasing Zn-Nb concentration.

Dielectric Behaviour of Pure and Dye Doped Nematic Liquid Crystal BKS/B07  [PDF]
Rajiv Manohar, Shashwati Manohar, V. S. Chandel
Materials Sciences and Applications (MSA) , 2011, DOI: 10.4236/msa.2011.27114
Abstract: The dielectric properties of pure nematic liquid crystal (BKS/B07) and dye doped (Rhodamine B and Anthraquinone) nematic liquid crystal have been investigated in a wide frequency range of 1 kHz to 10 MHz through the dielectric spectroscopic method at varying temperature. In addition to this optical transmittance and textures of the samples have also been observed with a polarizing microscope.
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