EFFECTS OF DEFORMATION ON THE ENERGIES OF METALS

In this work, a model for computing the correlation, binding and cohesive energy of deformed and undeformed metals was developed based on the structureless pseudopotential formalism. Using the developed model, the correlation, binding and cohesive energy of metals were computed and studied. Also, the computed binding and cohesive energy of metals were compared with available experimental values. The results obtained showed that correlation energy increases with increase in electron density parameter. An increase in deformation was found to cause corresponding increase in the correlation energy. The computed binding energy and cohesive energy of metals were in good agreement with experimental values. The results obtained further showed that deformation causes a decrease in the binding energy of metals and it does not cause a significant change in the cohesive energy of metals, although transition metals have high values of cohesive energy compared to alkaline and simple metals. Keywords: Metals, pseudopotential model,cohesive, binding and correlation energy

Thermal Properties of Soil Samples from Coastal Sand Landform in Ilaje Local Government Area of Ondo State, Nigeria

This study examines the thermal conductivity of some selected soil samples from coastal sandlandform inIlaje local government area of Ondo State, Nigeria. The soil samples were sieved into different particle sizes; 300 , 425 , 600 , 850 , and 1180 with appropriate mesh and moulded in form of a Lees disc. The thermal conductivity of the samples was determined using parallel plate method. The value of the thermal conductivity increase as the moisture content increaseand decrease with increase in particle sizes for the soil samples. The values of the thermal conductivity obtained rangedbetween 0.3444 and1.8894 . It was noted that the conductivity of the landforms conforms to the range of conductivities of soil required for some specific crops such as maize, cowpea, pineapple, okro and root crops. The results in the research would be useful to soil/building and soil scientists as well as modern mechanized farmers in determined appropriate land forms for agricultural and structural purposes

Dynamics of vertical profile of Radio Refractivity in Akure South-Western Nigeria.

This research investigated fractal and chaotic dynamics in the vertical profile radio refractivity in the atmosphere using Tsallis Entropy, Hurst Exponent and Largest Lyapunov Exponent (LLE). Daily temperature, relative humidity and radio refractivity data obtained from the European Centre for Medium Range Weather Forecasts (ECMWF) Re-Analysis Project at thirty seven (37) different atmospheric pressure level from 1979-2014 were used in this study. The Hurst Exponent parameter obtained, using the method of Detrended Fluctuation Analysis, in the radio refractivity profile studied showed that there is persistence across all levels. Tsallis entropy did not reveal any structure or significant variations from the tropopause to the surface. To determine if any of the radio refractivity is chaotic at any of the studied level, the Largest Lyapunov Exponent (LLE) was computed. Positive values were obtained at all levels for radio refractivity, indicating deterministic chaos in the profile of radio refractivity

Isolation and Characterisation of High Grade Nanosilicon from Coastal Landform in Ilaje Local Government Area of Ondo State, Nigeria.

The application of silicon and silicon based materials in industries and optoelectronic devices cannot be over emphasized due to their unique properties. The availability of high grade silicon has been subject of interest for manufacturers and industrialist as the material has from discovery been very much insufficient to cater for the numerous demands for different uses and utilization. Numerous efforts have been put together to adapt the properties of silicon through the manufacture and fabrication of semiconductor compounds to replace silicon in functionality. Notwithstanding, the quest for more silicon in the environment is yet unabated. This research centers on the isolation and characterisation of high grade nanosilicon from coastal landform in Ilaje Local Government Area of Ondo State, Nigeria due to the attractive nature of the landforms in terms of colour and texture. Sand from the selected study area were categorised into different forms according to their colour and silicon isolated using the magnesiothermic reduction while the nanosilicon was obtained using an appropriate ball milling process. The morphology of nanosilicon from Zion, Micheal-Ugbonla, and Oluwa Glass coastal landforms shows an agglomeration of particles with irregular shapes having average particle sizes of 58.98 nm, 77.82 nm, and 37.27 nm, respectively. The XRD spectra of the nanosilicon showed sharp, distinct peaks that indicate crystallinity of the samples. The percentages of nanosilicon value obtained ranges from 65.23%-80.30% and considered high enough to find specific useful industrial applications in lithium ion batteries, biomedical devices, opto electronic device utilization and computer industries

Optical, electrical and solid state properties of nano crystalline zinc sulphide thin films for device applications

Semiconducting Zinc Sulphide (ZnS) thin films were deposited on glass substrate using relatively simple Chemical Bath Deposition (CBD) technique. Nano crystalline ZnS thin films were fabricated in the study. Optical characterization of the films showed that the materials are transparent to visible light, opaque to ultraviolet radiation and near infra red radiation. The electrical conductivity decreases as the energy increases while the optical conductivity increases gradually over an energy range, and then sharply afterward. The XRD pattern showed that the deposited ZnS had distinct peaks at 31.59, 32.21, 44.76 and 46.73o respectively with 101, 110 and 111 preferred orientations. The energy band gap of ZnS film was found to be between 3.20–3.70eV with a direct band gap transition. These properties make ZnS thin films find useful applications as cover plates for solar energy panels and materials in the fabrication of semiconductor devices. In addition, the films were found to exhibit switching potentials.Keywords: Electrical, Optical, Solid state properties, Zn

Electrical Properties of Antimony (Sb) Metal Contacts to Silicon (Si) Thin Films

The study investigates the behaviour of the contacts formed by Antimony (Sb) metal to Silicon (Si) thin films for electric field values 10 – 100V/m. Measurements of I-v characteristics were obtained at temperatures 303, 313, 323, 333, 343 and 353K respectively. The results show linear I – V relationship over a specified range of voltage (10 – 60V) and at higher voltage (>60V), there was deviation from linear behaviour for each of the temperature. The electrical surface conductance of the samples increases with temperature while the saturation current density decreases with temperature. Nonetheless, the study revealed very little increase in the values of the barrier heights with increasing temperature. (Nigeria Journal of Pure and Applied Physics: 2003 2 (1): 40-44

Analysis of data on net longwave, shortwave and global radiation during transition period in a tropical station in Southwestern Nigeria

347-352The present study examines the distribution of surface radiation balance components measured during the Nigerian Micrometeorological Experiment (NIMEX-1). A field study was conducted to measure surface heat fluxes in the boundary layer during the transition period which marks the end of dry season and the onset of wet season (15 February and 10 March 2004) in Southwestern part of Nigeria. Regression equations were obtained using daily average values and hourly mean values between net shortwave and net longwave radiation, respectively with the global radiation. Higher correlations with low standard error of measurement were obtained for daily mean values than hourly mean values. It was also observed that the peak value of each radiation during the period occurred for two hours in the afternoon on an average as expected

Design of an Instrumentation Unit with Datalogger for Heat Flow Measurement in Solid Metals

An instrumentation unit that measures heat flow along the test column of solid metal samples is described. The study also describes the design of a datalogger using Arduino Mega Microcontroller. The designed instrumentation unit incorporates current and voltage sensing unit, ten thermocouple sensors and amplifiers, microSD card shield, two LCDs, four microcontrolled switching relays and a 12 V DC water pump motor. The heat flow parameters measured by the instrumentation unit includes temperature gradient, heater current and heater voltage. The designed datalogger logs the measured value of temperature, current and voltage at a time of ten minutes. An area of application for this study is in the development of a device for measurement of thermal conductivity of solid metals. It is an improvement over existing heat flow measurement techniques