IOSR-JAP   Volume-6 ~ Issue-5 ~ Sep-Oct 2014

ABSTRACT: Flash evaporated amorphous GaxSe1-x (x = 0, 1, 2, 3, and 4 atomic %) on glass substrates have been investigated within a 500nm-1500nm spectral range. Film thicknesses explored were ; 200±10nm, 265±10nm, 330±10nm, and 400±10nm. The effect of film thickness and gallium content on the as-deposited thin films has been established. As the gallium content increases, both the optical transmittance and band gap energy decrease. Increase in film thickness led to a decrease in optical transmittance and an increase in the band gap energy. The other optical parameters like the absorption coefficient, extinction coefficient, refractive index, real part and imaginary part of dielectric constant increase with increase in gallium content and film thickness.

Keywords: Amorphous thin film, Film thickness, Ga-Se alloy, Optical property

[1] N. Mohd and M. Zulfequar, DC Conductivity and dielectric behaviour of glassy Se100-xZnx alloy, Journal of Inorganic Non- Metallic Materials, 2, 2012, 11-17.

[2] M. Popescu, Self-organization in amorphous semiconductors and chalcogenide glasses, Journal of Advanced Materials, 8(6), 2006, 2164-2168.

[3] E. A. Davis, Electronic and structural properties of amorphous semiconductors (Academic Press: London, 1973).

[4] A. A. Mulama, J. M. Mwabora, A. O. Oduor, and C. M. Muiva, Optical properties and Raman studies of amorphous Se-Bi thin films, The African Review of Physics, 9(6), 2014, 33-37.

[5] P. K. Johnson, The effect of trapping defects on CIGS solar-cell performance, doctoral diss., Colorado State University, USA, 2003

ABSTRACT: When radio waves propagate through the earth's neutral atmosphere, the radio signals are affected significantly by the variability of its refractive index, which causes primarily in the delay of the arrival, usually referred to as the tropospheric delay. The Global Positioning System (GPS) is space-based radio navigation. The GPS system receiver provides exact location and time information for an unlimited number of users in all weather, day and night, anywhere in the world. The GPS used three frequencies that are (L1 = 1.57542 GHz, L2 = 1.22760 GHz and L3 = 1.38105 GHz). The work part mainly focuses on how to illustrate and model the effects of the atmospheric constituents such as, water vapor, clouds, rain and snow on the GPS frequencies.The differential phase shift (Δ∅) in case of rain is caused by the oblate rain drop that is has two different axes, and because of the difference of the concentration of rain drops, also (Δ∅) doesn't depend on the temperature but increase with the increase of the frequency where the values of (Δ∅) are 6 deg/km for L1, 5 deg/km for L2 and 5.4 deg/km for L3. The differential attenuation (ΔA) in case of rain in addition to depend on the shape of rain drop and the concentration of drops, it depends on the temperature and the frequency. The (Δ∅) in case of snow caused by the irregular shape of snow particle and depends on the temperatures and the frequency. The (ΔA) in case of snow has very low values in different temperatures and frequencies.

Keywords: propagation delays,GPS signals, radio waves.

[1] E.D. Kaplan and C.J. Hearty, 2006: Understanding GPS: Principles and Applications. Second Edition, Artech House Inc.,

[2] B.W. Parkinson et al, 2002: Global Positioning System: Theory and Applications. Volume I, American Institute of Aeronautics and Astronautics, Inc.,.

[3] Bevis, M. et al, 1992: GPS meteorology: sensing of atmospheric water vapor using the Global Positioning System. Journal of Geophysical Research, Vol. 97, No. D14.

[4] Westwater E.R., 1967: Analysis of the correction of range errors due to atmospheric refraction by microwave radiometer techniques. ESSA Tech-Rep. IER 30-ITSA30

[5] Van Vleck J.H., and V.F. Weisskopf , 1947 : On the Shape of collision broadened lines . Rev. of Modern Physics, Vol. 17.

ABSTRACT: We have studied the Hoyle-Narlikar C-field cosmology with spherical symmetric five dimensional metric space time. Using methods of and Padmanabham [1], the solutions have been studied when the creation field C is a function of time t only. The geometrical and physical aspects for model are also examined

[1]. J.V. Narlikar, T. Padmanabhan (1985) Phys. Rev. D 32, 1982.
[2]. G.F. Smoot, et al. (1992) Astrophys. J. 396, 21.
[3]. J.V. Narlikar, et al. (2003) Astrophys. J. 585, 1.
[4]. F.Hoyle (1948) Mon. Not. R. Astron. Soc. 108,372.
[5]. H. Bondi, T. Gold (1948) Mon. Not. R. Astron. Soc. 108,252.
[6]. F. Hoyle, J.V. Narlikar (1966) Proc. R. Soc. (London) A290, 162

ABSTRACT: Synthetic fertilizers are commonly used for growing all crops, with application rates depending on the soil fertility. Urea is an example of a synthetic organic fertilizer, an organic substance manufactured from inorganic materials. Organic fertilizers have been known to improve biodiversity, and long term productivity of soil, and may prove a large depository for excess carbon dioxide. Urea fertilizer provides nitrogen, which promotes green leafy growth. Urea has the highest nitrogen content, equal to 46% and it can be used for all types of crops and soils1. This investigation based on the behavior of propagation of ultrasonic waves in fertilizer system are now rather well established as on effective means for examine certain physical properties of the materials. Ultrasonic velocity, density and viscosity values for the fertilizer urea are found in the concentration range of 0.3m to 2.1m at various temperatures from 308˚K to 323˚K. The values of acoustical and thermodynamical parameters such as adiabatic compressibility, acoustic impedance, relaxation time, molar hydration number, free length, apparent molal volume, and apparent molal compressibility are determined. Their variation with concentration is useful in understanding the nature of molecular interaction in terms of physical parameters. These results were confirmed by soil test. A soil test gives the information about the availability and lack of nutrients in the soil. The quantity of available nutrients in the sample determines the amount of fertilizers that is recommended for a particular crop. This is also confirmed by the values of absorption coefficient of aqueous urea solution at higher concentration.

Key Words: Ultrasonic velocity, absorption coefficient, relaxation time, hydration number, soil test.

[1]. K.Vaidyanathan, A.Venkateswaran & R.Ramaswamy, Agricultural Chemistry, Priya Publications, Karur 2000.
[2]. S.Chauhan, Kuldeep Kumar, and B.S. Patial., Indian Journal of Pure and Applied Physics,Vol 51 p.p 531-541 August 2013.
[3]. K.Ramanathan, S.Ravichandran, Journal of Pure and Applied Ultrasonics, 26,p.p 12-17 2004.
[4]. Sunanda S.Aswale Shashikant R. Aswale, Rajesh S.Hajare, Journal of Chemical and Pharmaceutical Research, 4(5): 2671-2677, 2012.
[5]. V.N.Maruya, Diwinder Kaur Arora, Er. Avadhesh Kumar Maruya, R.A.Goutam., World of Sciences Journal ISSN 2307-3071,2013 (02).