IOSR-JAP   Volume-9 ~ Issue-5 ~ Sep-Oct 2017

ABSTRACT: Wedge filters are generally used to alter the shape of isodose lines to achieve desired dose coverage to target and minimize the hyper dose as well. Aim: Main aim of this study was to analysis the dosimetric features of Varian's physical wedge and enhanced dynamic wedge. Materials and Methods: The plan was evaluated in Varian's eclipse planning system. In order to compare the isodose lines alteration, all the plans were prepared in water phantom with 10cmx10cm field size for 6 and 15MV photon. The physical wedges of angle 15 °, 30°, 45 °and 60°; and the same of enhanced dynamic wedges were taken for this study. Beam profiles were generated by using OCTAVIUS Detector 729 T10040 and MultiCheck software............

Keywords: wedge factor, physical wedge, Isodose line, enhanced dynamic wedge

[1]. Sathiyan Saminathan,⁎ Ravikumar Manickam, and Sanjay S. Supe. Comparison of dosimetric characteristics of physical and enhanced dynamic wedges, 2012 ; 17(1): 4–12 [Rep Pract Oncol Radiother]
[2]. Misbah Ahmad, Amjad Hussain,1 Wazir Muhammad,2 Syed Qaisar Abbas Rizvi,3 and Matiulla .Studying wedge factors and beam profiles for physical and enhanced dynamic wedges, 2010 ; 35(1): 33–41. [J Med Phy]
[3]. Palta J., Daftari I., Suntharalingam N. Field size dependence of wedge factor. Med Phys. 1988;15(4):624–6. [PubMed]
[4]. 12–14. ICRU; Washington, DC: 1976. (Determination of absorbed dose in a patient irradiated by beams of X or gamma rays in radiotherapy procedures. ICRU Ref 24).
[5]. Kinhikar RA, Sharma S, Upteti R, Tambe CM, Deshpande DD, Shrivastav SK, et al. Commissioning of motorized wedge for the first Equinox-80 telecobalt unit and implementation in the Eclipse 3D treatment planning system. Australas Phy Eng Sci Med. 2007;30:127–37. [PubMed]

ABSTRACT: An optical wave being composed of two orthogonal electromagnetic field components varying with amplitude and frequency. A polarized light occurs when these two components differ in phase or amplitude. Polarization in optical fiber (polarization maintaining optical-fibers : maintaining low PMD) has been extensively studied and methods are available to minimize the phenomenon. Lower the PMD higher will be the information carrying capacity of the optical fiber, hence low PMD should be maintained". Here, basic
principles and technical background are introduced in explaining how the polarization in fiber optics works.

Keywords:Electric field E, Magnetic field H, Amplitude (A0), Frequency  , wave vector k, Phase difference , SOP (State of Polarization), Polarized optical wave, PMD (Polarization mode dispersion).

[1] Optical fiber communication system, Tata Mc Graw-Hill, IVth Edition by Gerd Keiser.
[2] https://www.newport.com/t/polarization-in-fiber-optics

ABSTRACT: An automated weather monitoring station was installed at an open space within the main campus of Usmanu Danfodiyo University, Sokoto (UDUS), where hourly global solar radiation, number of sunshine hours, minimum and maximum temperatures as well as percentage of relative humidity data were monitored for a period of one complete calendar year (June, 2016 to May, 2017). The objective of this study is to compare the performance of selected empirical models commonly used for the estimation of global solar radiation in UDUS with ground based measured global solar radiation data. Five different models were selected and used for the study. The results obtained from the models were compared with the monthly average measured global solar data for the location. The comparism was made using four statistical error analysis namely; mean bias error (MBE), root mean square error (RMSE), mean percentage............

Keywords: Solar Radiation, Renewable Energy, measurement, Statistical test and Estimation

[1] Abdulsalam, D., Mbamali, I., Mamman, M. and Saleh, Y. M. (2012) An Assessment of Solar Radiation patterns for sustainable implementation of Solar Home Systems in Nigeria, American International Journal of Contemporary Research 2(6), pp. 238-243
[2] Argungu, G. M., Aliyu, M. and Ugwuoke, P. E. (2005) Wind Energy Resources in Nigeria for Power Generation, Nigerian Journal of Renewable Energy, Vol. (13), 1&2, Pp 65-68
[3] Augustine, C. and Nnabuchi, M. N. (2009) "Relationship between Global Solar Radiation and Sunshine Hours for Calabar, Port-Harcourt and Enugu, Nigeria". International Journal of Physical Sciences, Vol. 4 (4) pp 182-188.
[4] Chiemeka, I. U. (2008) "Estimation of Solar Radiation at Uturu, Nigeria". Int. J. Physical Science, Vol. 3 (5) pp 126-130.
[5] Dehghan, A. A., Besharat, F. and Faghig, A. R., (2013) "Empirical Models for Estimating Global Solar Radiation: A Review and Case Study". Renewable and Sustainable Energy Review, Vol. 21 pp 798-821 doi: 10.1016/j.rser.2012.12.043

ABSTRACT: After having pierced the mystery of quantum gravitation in [7], the purpose of this article is to elucidate the phenomenon of quantum entanglement. Résumé : Après avoir percé dans [7] le mystère de la gravitation quantique, le but de cet article est d' élucider
le phénomène de l'intrication quantique.

Keywords:Intrication, Gravité, quantique, relativité, restreinte, générale, trou noire, unification, théorie du tout.

[1] Albert Einstein, Boris Podolsky et Nathan Rosen, « Can Quantum-Mechanical Description of Physical Reality Be Considered
Complete? », Phys. Rev., 47, , 777-780
[2] Nicolas Gisin ( Alain Aspect), L'Impensable Hasard : Non-localité, téléportation et autres merveilles quantiques, Paris, Odile Jacob, ,
170 (ISBN 978-2-7381-2831-7)
[3] Gabriel Popkin, « China‟s quantum satellite achieves "spooky action‟ at record distance » [archive] [« Un satellite quantique chinois
réalise l'« action fantôme » à une distance record »], sur sciencemag.org, (consulté le 4 juillet 2017)
[4] A. Aspect, Proposed experiment to test the non-separability of quantum mechanics [archive], Phys. Rev. D 14, 1944–1951 (1976)
[5] Verschränkte Photonen sollen Kommunikation und Daten schützen » [archive], Maschinenmarkt, (consulté le 22 juillet 2017)

ABSTRACT: With the study of nanoscale effects, Nano electromechanical systems (NEMS) present interesting and unique characteristics, which diverges greatly from their predecessor micro-electromechanical systems (MEMS). When MEMS are scaled to submicron dimension[5], NEMS are formed. NEMS are able to preserve very high mechanical responsivity (small force constants); the quality (Q) factors of resonance are remarkly higher than those of electrical resonant cavity (i.e. in range Q = 103 – 105) and acquire tremendously high fundamental frequencies concurrently. These features are responsible for technological applications like signal processing components, actuators and ultrafast sensors. However, some technological fundamental challenges still exist due to NEMS optimization. This paper aims..........

Keywords:Nano electromechanical system, attribute, transducers, carbon nanotubes..

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ABSTRACT: Lattice constant of Iron Sulfide (FeS2) was measured at various temperature by X – ray diffraction method. Slight nonlinearity in the temperature variation of lattice constant was observedat high temperature. The data were fitted to three term polynomial in the temperature range of 300K to 700K. aT = 5.4062 + 0.414 x 10-4 T + 1.031 x10-8T2. By Differentiating the equation we get the following equation for linear expansion as α = 7.64 x 10 –6.+0.380 x 10 -8.Coefficient of expansion increases linearly with temperature in pyrite crystal.

Keywords: X ray diffraction, Lattice Constant and Themal Expansion Coefficeint.

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ABSTRACT: Calcium Fluoride has the fluorite structure with four molecules per unit cell. It is the prominent representative of the material known as super ionic conductors which develops high electrical conductivity at high temperatures. Because of this it has attracted considerable attention. In recent years numbers of properties were investigated. We are interested in Thermal Expansion of Caf2. The lattice Constant and coefficient of expansion Caf2 has been determined over the range of 300- 700k. Coefficient of expansion at room temperature is calculated as it increases with temperature where as the Gruneisen parameter decreases with temperature.

Keywords: X –ray diffraction, Lattice Constants, Thermal Expansion Coefficient and Gruneisen constant.

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ABSTRACT: Basic and foremost objective of Solid-state Physics is to explore lattice dynamics. It can be accomplished only after obtaining comprehensive knowledge of Lattice properties such as specific heat, elastic constants, and thermal expansion coefficients. Specific heat and elastic constants have been measured for a large number of elements in pure form as well as in the form of important binary alloys, over a wide range of temperatures, from the neighborhood of absolute zero to the temperatures beyond melting points. According to Debye characteristic temperature (0D), the low temperature limit must be in the vicinity of 0o/100, where the wavelengths of the thermal waves are longer than inter atomic distance..........

Keywords: Lattice constant, Thermal Expansion, Gruneisen parameter

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ABSTRACT: Purpose: Quantify and evaluate the mechanical stability and image quality emerged by (XVI) system of over time. Measuring the imaging radiation dose delivered to patient during CBCT scan to study the impact of imaging dose on the total effective dose received by patient. Materials and Methods: In this study we monitor the mechanical stability of XVI system over time by imaging a dense sphere phantom positioned at isocenter and the stability of 3Dimage quality properties produced by CBCT using Catphan phantom 503over time. Finally, both CT dose index (CTDI) and dose measurements with TLDs were performed ..........

Keywords: IGRT, XVI, CBCT, Image Quality, Imaging dose

[1]. Aird EGA. Second cancer risk, concomitant exposures and IRMER (2000). Br J Radiology,77(924):983–95 (2004)
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ABSTRACT: An attempt has been made to investigate the effect of thermo diffusion on hydro magnetic mixed convective Non-Darcy flow in a vertical channel with temperature gradient dependent heat source using Galerkin finite element technique .The governing equations of flow, heat and mass transfer have been solved to obtain velocity, temperature , concentration, shear stress and rate of Heat and Mass transfer numerically for different values of Q,D-1,Sr,F and Pr.

Keywords: Thermo diffusion, Non-Darcy flow, finite element analysis, temperature gradient dependent heat source.

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ABSTRACT: We present a new solution to the cosmological constant problem in quantum theory of gravity with torsional instantons. These particles exist in a first order formulation of Giddings-Strominger axionic gravity carrying Nich-Yan topological charge. Due to tunneling effects, the nonperturbative ground state is produced and it is shown to be stable under quantum fluctuations. It is also shown that in view of the Hubble constant, the associated vacuum angle known as Barbero-Immirzi topological parameter, gets fixed to a numerical value. The energy of the  -vacuum has a natural interpretation as the dark energy which is believed to be responsible for the accelerated expansion of the universe at present.

Keywords: Barbero-Immirzi topological parameter, Nich-Yan topological charge, -vacuum, torsional instantons.

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