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An Alternate Method for the Determination of the Raman Cross Sections of Optical Phonons in Uniaxial Crystals: Application to LiNbO3
B. Mohamadou,
E. Bouhari,
R. Erasmus
Issue:
Volume 4, Issue 6, November 2015
Pages:
371-378
Received:
10 August 2015
Accepted:
13 September 2015
Published:
7 December 2015
Abstract: The present paper is devoted to the derivation of an alternate and simple method based on the rotation of the crystal in view of the determination of the Raman cross-sections of optical phonon in uniaxial and biaxial crystals. The Raman polarisability tensor whose trace remains invariant under an orthogonal transformation is established as function of the crystal rotation position. The resulting angle dependent Raman scattered intensity is finally used to accurately describe the area under the peak which is measured from the polarised Raman spectra of the lithium niobate single crystal recorded under the backscattering scheme; The extracted parameters from the fit such as integrated areas are then plotted as functions of the crystal rotation angles. This allows to quantitatively determinate the relative phase and the relative values of the Raman tensor elements.
Abstract: The present paper is devoted to the derivation of an alternate and simple method based on the rotation of the crystal in view of the determination of the Raman cross-sections of optical phonon in uniaxial and biaxial crystals. The Raman polarisability tensor whose trace remains invariant under an orthogonal transformation is established as function...
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Study the Effect of Polystyrene on Ground Tire Rubber / High Density Polyethylene Compatibility
Zuhair J. Abdul Amer,
Ali Abdul Amer Al-Zubaidi,
Hiba Imad Abdul Kareem
Issue:
Volume 4, Issue 6, November 2015
Pages:
379-384
Received:
15 November 2015
Accepted:
22 November 2015
Published:
7 December 2015
Abstract: This paper deals with the study of properties for recycling tires toughening thermoplastic polymer. Large amounts of waste that arise daily as a result of scientific and technological progress with increasing humane consumer goods. This gave rise to the problem of the accumulation of the waste and its effect on the environment. So many researchers work to use this waste in useful products, and thus can achieve economic and environmental goals. The objectives of this study are to incorporate ground tire rubber (GTR) waste scrap into a thermoplastic matrix, recycled high density polyethylene (rHDPE) to improve the weakness of the mechanical properties due to the lack of compatibility between two polymers, a surface treatment was achieved by recycled polystyrene solution to increase the bonding between rHDPE and GTR and the properties of the blend were determined and compared. Several tests were conducted to determine the specifications of the resulting mixture with addition different ratios of GTR, such as tensile strength, bending strength, hardness, density, optical microscope examination and scanning electron microscope. The results show that the results showed improvement in tensile strength, bending strength and hardness, on the other hand, a decrease in elongation comparing with untreated samples.
Abstract: This paper deals with the study of properties for recycling tires toughening thermoplastic polymer. Large amounts of waste that arise daily as a result of scientific and technological progress with increasing humane consumer goods. This gave rise to the problem of the accumulation of the waste and its effect on the environment. So many researchers ...
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First-Principles Study on the Luminescence Properties of SrAl2O4: Eu2+, Dy3+
Xiao Wu,
Zhijie Li,
Yufeng Zhang
Issue:
Volume 4, Issue 6, November 2015
Pages:
385-389
Received:
16 December 2015
Published:
17 December 2015
Abstract: In order to improve SrAl2O4: Eu2+, Dy3+ luminescent properties, explore Eu2+ and Dy3+ in SrAl2O4, using a plane-wave ultrasoft pseudopotential method under the density functional theory framework, were established SrAl2O4, SrAl2O4: Eu2+ and SrAl2O4: Eu2+, Dy3+ supercell model, and calculated their population numbers, band structure and density of states. The results showed that: the luminescence center Eu2+ doping SrAl2O4 makes impurity level appearing in the forbidden band and the conduction band, and produce photoluminescence effect. On this basis, the auxiliary activator Dy3+ doping makes the luminous intensity higher, persistence time longer.
Abstract: In order to improve SrAl2O4: Eu2+, Dy3+ luminescent properties, explore Eu2+ and Dy3+ in SrAl2O4, using a plane-wave ultrasoft pseudopotential method under the density functional theory framework, were established SrAl2O4, SrAl2O4: Eu2+ and SrAl2O4: Eu2+, Dy3+ supercell model, and calculated their population numbers, band structure and density of s...
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Effect of Biofield Energy Treatment on Physical and Structural Properties of Calcium Carbide and Praseodymium Oxide
Mahendra Kumar Trivedi,
Rama Mohan Tallapragada,
Alice Branton,
Dahryn Trivedi,
Gopal Nayak,
Omprakash Latiyal,
Snehasis Jana
Issue:
Volume 4, Issue 6, November 2015
Pages:
390-395
Received:
30 October 2015
Accepted:
17 November 2015
Published:
21 December 2015
Abstract: Calcium carbide (CaC2) is known for its wide applications in the production of acetylene and calcium cyanamide, whereas praseodymium Oxide (Pr6O11) is used in sensors and high-temperature pigments. The present study was designed to evaluate the effect of biofield energy treatment on the physical and structural properties of CaC2 and Pr6O11 powder. The powder samples of both compounds were equally divided into two parts, referred as control and treated. The treated part of both compounds was subjected to Mr. Trivedi’s biofield energy treatment. After that, both control and treated samples were investigated using X-ray diffraction (XRD) and Fourier transform infrared (FT-IR) spectroscopy. The XRD data revealed that the biofield energy treatment has increased the lattice parameter of unit cell by 3.35% in the treated CaC2 sample as compared to the control. The density of treated CaC2 sample was reduced upto 4.49% and molecular weight was increased upto 4.70% as compared to the control. The crystallite size of CaC2 was reduced from 98.19 nm (control) to 52.93 nm in the treated CaC2 sample as compared to the control. The FT-IR analysis exhibited that the absorption band attributed to C=C stretching vibration was shifted to higher wavenumber as compared to the control. Thus, above data suggested that biofield energy treatment has considerable impact on the physical and structural properties of CaC2. Besides, in Pr6O11, the XRD did not show any significant change in lattice parameter, density and molecular weight. However, the FT-IR spectra revealed that the absorption band attributing to Pr-O stretching vibration was shifted from 593 cm-1 (control) to higher wavenumber 598 cm-1 in the treated Pr6O11 sample. Therefore, the biofield energy treatment could be applied to modify the CaC2 and Pr6O11 powder for the use in chemical industries.
Abstract: Calcium carbide (CaC2) is known for its wide applications in the production of acetylene and calcium cyanamide, whereas praseodymium Oxide (Pr6O11) is used in sensors and high-temperature pigments. The present study was designed to evaluate the effect of biofield energy treatment on the physical and structural properties of CaC2 and Pr6O11 powder. ...
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Effects of Impurities on the Percussion and Tensile Properties of Recycled Al-Cu-Si (Cu2Mg8Si6Al5) Alloys
Sujana Rao Nakkanti,
Kamprasad Chodagudi,
Vijayakumar Chennupati,
Mahesh Rayavarapu
Issue:
Volume 4, Issue 6, November 2015
Pages:
396-402
Received:
17 November 2015
Accepted:
23 December 2015
Published:
4 January 2016
Abstract: This paper deals with the study of Mechanical properties (Percussion resistance, Ultimate and Yield strength) of cast alloy Cu2Mg8Si6Al5. It has been developed by addition of Al-Cu-Si with 83.334% Al, 16.23% Cu and 0.165% Si. Solidification of Al-Cu-Si alloys has been realized by melting of industrial and machine shop scrap in a pit type resistance furnace with a clay graphite crucible and casting in green sand moulds at maximum temperature of 640°C. The outcome final castings were then machined according to ASTM-A 370 standards for the percussion, ultimate and yield strength of specimen. The results on the basis of various trails of microstructure and practical approach depicted that Cu and Si addition increased the Percussion strength as well as Ultimate and Yield strength for the alloy, while iron addition reduces. However, addition of manganese neutralized the detrimental effects of the iron, which presented in the industrial scrap. The results are given a good agreement with the existing literature on alloys which can be widely used for industrial applications like automobile, aero space, defence etc.
Abstract: This paper deals with the study of Mechanical properties (Percussion resistance, Ultimate and Yield strength) of cast alloy Cu2Mg8Si6Al5. It has been developed by addition of Al-Cu-Si with 83.334% Al, 16.23% Cu and 0.165% Si. Solidification of Al-Cu-Si alloys has been realized by melting of industrial and machine shop scrap in a pit type resistance...
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Influence of the Diffusion Effect Caused by Welding Heat Input Lead to the Changes of Mechanical Properties Which Entering into the FEM Model of Cladding Tube Bending
Jakub Horváth,
Jiří Janovec,
Michal Junek
Issue:
Volume 4, Issue 6, November 2015
Pages:
403-408
Received:
18 January 2016
Published:
20 January 2016
Abstract: This paper deal with redistribution of chemical elements around cladding surface of composite tube. Motivation is that change of chemical composition cause change in microstructure and mainly changes in mechanical properties. Local changes of mechanical properties can cause inaccuracy or wrong results obtained from FEM modeling of bending process of cladding tube. In short paper present redistribution of chemical elements caused by heat input during production of tube. Redistribution caused by heat input from weld attachment of connector which is used during production of membrane waterwall is discussed. Microstructure evaluation of base material and cladding layer is compared with measurement of hardness. Measurement of microhardness in specific areas of cladding tube was done. Microhardness is compared with measurement of chemical composition via EDX in scanning electron microscope.
Abstract: This paper deal with redistribution of chemical elements around cladding surface of composite tube. Motivation is that change of chemical composition cause change in microstructure and mainly changes in mechanical properties. Local changes of mechanical properties can cause inaccuracy or wrong results obtained from FEM modeling of bending process o...
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