IOSR-JAP   Volume-7 ~ Issue-2 ~ March-April 2015

ABSTRACT: Trends in the present-day climate of Nigeria were investigated by analyzing the historical temperature and rainfall data records in the context of climate change. The associated potential impacts and coping strategies were examined. The data for the study were collected from the archives of the Nigerian Meteorological Agency, (NIMET), Oshodi Lagos and spanned from 1950 – 2012. The basic data consist of monthly mean daily minimum and maximum temperatures and monthly rainfall totals in six meteorological stations selected from the various agro meteorological zones in Nigeria. These stations are Maiduguri, Kaduna, Makurdi, Enugu, Ibadan and Calabar. These basic data were converted to annual rainfall totals and annual mean daily minimum and maximum temperatures for the analyses.

[1]. Abiodun, B.J., Salami, A.T. and Tadross, M. (2011). Climate Change Scenarios for Nigeria: Understanding Biophysical Impacts. Climate Systems Analysis Group, Cape Town, for Building Nigeria's Response to Climate Change (BNRCC) Project, Ibadan, Nigeria: Nigerian Environmental Study/Action Team NEST, 11.

ABSTRACT: Measurements were made on the Hall coefficient and transverse magnetoresistance of bismuth alloys containing small amount of gallium and indium as functions of magnetic filed at different constant temperatures. Change of sign of the Hall coefficient with magnetic field is observed at low temperature. Change of sign of the Hall coefficient with rise in temperature is a common phenomenon in case of acceptor doped semiconductor. But a reversal of sign in the Hall coefficient with magnetic field is not that commonly observed. Values of the magnetoresistance and Hall coefficient strongly vary with magnetic field strength. The magnetoresistance does not obey the quadratic dependence on magnetic field strength. The observed results may be a consequence of the particular band structure which allows the presence of different kinds charge carriers with high and strongly anisotropic mobilities. Keywords: bismuth, electrical transport, Hall coefficient, magnetoresistance, semimetal

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ABSTRACT: The present work makes use of experimental ac complex impedance data to obtain the electrical parameters like electrical conductivity and activation energy of ((Bi0.5Na0.5)0.94Ba0.06TiO3+0.2 wt%Nb2O5)–PVDF 0-3 composites with 10, 20 and 30 vol. percentage of ((Bi0.5Na0.5)0.94Ba0.06TiO3+0.2 wt%Nb2O5) in the frequency range 1kHz–1 MHz over a temperature range of 35oC-145°C. SEM micrographs exhibited good dispersion of almost spherical dense grains (sizes ranging between 8-14 μm). Cole-Cole analysis for frequency-dependent complex impedance data indicated the presence of grain-boundary effect along with the bulk contribution, thereby showing the NTCR character for the composites, especially in the lower frequency and higher temperature regime. Results were also analyzed via the electric modulus formalism.

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ABSTRACT: The present paper reports a temperature dependent calculation of effective mass and scattering rate for the compound UPT3. It is a typical heavy electron compound. The calculation uses the Kramers-Konig relations within the model of Millis and Lee . The results are compared with reported experimental data

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ABSTRACT: In quantum mechanics, the variation method is one way of finding approximations to the lowest energy Eigen state or ground state, and some excited states. The method consists in choosing a "trial wave function" depending on one or more parameters, and finding the values of these parameters for which the expectation value of the energy is the lowest possible. The wave function obtained by fixing the parameters to such values is then an approximation to the ground state wave function, and the expectation value of the energy in that state is an upper bound to the ground state energy. In the present work, Particle in a box problem is solved by applying variation method & by using MATLAB & MATHCAD software. The wave functions are solved for the ground state & the first excited state. The results obtained are compared with the chosen trial functions of various orders and their combinations. By this one can able to apply the theoretical knowledge and clearly understand the concept of Particle in a box problem.

Keywords: Computation Method, Ground State Energy, Trial Functions, Variation Energy, Variation Method

[1]. Variation Methods Applied to the Particle in a Box - W. Tandy Grubbs, Department of Chemistry, Unit 8271, Stetson University, DeLand, FL 32720 (wgrubbs@stetson.edu)
[2]. Introduction to Numerical Methods and Matlab Programming for Engineers - Todd Young and Martin J.Mohlenkamp,Department of Mathematics,Ohio University, Athens, OH 45701,youngt@ohio.edu,August 7, 2014

ABSTRACT: In this communication, a simple and low cost gas sensor setup has been design and fabricated to measure the gas sensing response of metal oxide thin films. The setup is also extended for temperature dependent gas response by designing a micro furnace using a small resistive heating element that is easily available. Importance of prepared setup lies in its easy design, portability, reliability and low cost to carryout gas sensing measurements both at laboratory and field applications. It is tested using tin oxide thin films deposited on glass substrate using chemical spray pyrolysis. It was found to be very sensitive even for a small amount of gas and the recorded gas response to electrical resistance change are quite reproducible. Hence here in it is proposed that the present set is an innovative design to achieve low cost and portable gas sensing device.

Key words: Metal oxide, design and fabrication of gas sensor, tin oxide film, temperature dependent gas response.

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ABSTRACT: The transmittance (T), Reflectance(R), and optical parameters of the system Se80Ge20-xInx show nonlinear behavior during the wavelength range250-2500nm.This was attributed to the dependence of the obtained physical quantities on the light energy intensity. The obtained values of the optical parameters, refractive index (n), extinction coefficient (k) and the absorption coefficient, 𝛼 𝑑crease as the photon energy decreases. The characteristic peaks of T, R, n, k, and (𝛼) were shifted towards low photon energy values as the thin film samples were thermally annealed at 383k for one hour. This shift slightly increased as the annealing temperature increased to 493k for one hour. The optical energy gap has been decreased as the Indium content and the annealing temperature increased.

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ABSTRACT: Forward–backward grey particle productions following 2.1A GeV4He and 2.2A GeV7Li interactions with emulsion nuclei are investigated. The grey particle multiplicity characteristics are found to be dependent only on the target size where the projectile size and energy are not effective. The validity of the nuclear limiting fragmentation hypothesis is examined with respect to the projectile size and energy. The characteristic shape of the forward and backward emitted grey particle multiplicity distributions is decay curves. These distributions are approximated by an exponential decay law.

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