Open Access Original Research Article

Numerical Treatment of General Third Order Ordinary Differential Equations Using Taylor Series as Predictor

B. G. Ogunware, D. O. Awoyemi, L. O. Adoghe, O. O. Olanegan, E. O. Omole

Physical Science International Journal, Page 1-8
DOI: 10.9734/PSIJ/2018/22219

This work considers the direct solution of general third order ordinary differential equation. The method is derived by collocating and interpolating the approximate solution in power series. A single hybrid three-step method is developed. Taylor series is used to generate the independent solution at selected grid and off grid points. The order, zero stability and convergence of the method were established. The developed method is then applied to solve some initial value problems of third order ODEs. The numerical results of the method confirm the superiority of the new method over the existing method.

Open Access Original Research Article

Direct Current in Non-steady-state Photovoltaic Effect

I. N. Volovichev

Physical Science International Journal, Page 1-11
DOI: 10.9734/PSIJ/2018/39551

A new non-steady-state photovoltaic effect in a uniform bipolar semiconductor doped with impurities changing their charge state under illumination is predicted. Direct electric current is shown to arise in the ring-shaped uniform bipolar semiconductor sample illuminated by a moving light pattern. The physical basis of the effect is the simultaneous change of the charge carriers density and mobility, as well as the difference in lifetimes of the ionized impurities, charge carriers and the light pattern traveling time along the semiconductor sample.

The expression for the short-circuit photocurrent in the semiconductor ring is obtained under the quasineutrality assumption, its dependence on the light pattern parameters, as well as on the semiconductor properties and on the sample size is analyzed. It is shown that there are the optimum light pattern velocity and the optimum semiconductor length providing the largest magnitude of the photovoltaic effect. It is found that the short circuit photocurrent is proportional to the squared amplitude of the light intensity modulation at its arbitrarily small value. The photocurrent is also sensitive to the mean intensity of light pattern and may change its sign with increasing the mean intensity of the incident light. Under a sufficiently strong illumination the photovoltaic effect vanishes.

Open Access Original Research Article

Evaluation of Momordica balsamina Seed Oil for Its Potential as Feedstock for Biodiesel Production

V. O. Ajibola, S. E. Abechi, J. Yusuf

Physical Science International Journal, Page 1-9
DOI: 10.9734/PSIJ/2018/37547

This paper sought to evaluate the potential of oil obtained from balsam apple (Momordica  balsamina) for biodiesel production. Oil was extracted from the seed using n-hexane in a soxhlet extractor, then transesterified to biodiesel using single step alkali hydrolysis. The biodiesel so produced was analyzed for their physicochemical and fuel properties using American Standards for Testing and Materials procedures. GC-MS was used to quantify the Fatty acid methyl esters yield. Percentage oil yield was 33.21 ± 0.18%. The physicochemical properties of the oil showed high acid values (M. balsamina 9.958 ± 0.5 mg/KOH/g). The percentage oil degumming was 10.12 ± 0.6%. Some critical fuel parameters for the biodiesel produced from the oil showed compliance with American Standards for Testing and Materials and European standard specifications. The result of biodiesel produced showed; Colour 2.9 ± 0.0, cetane number 57.699 ± 0.23, flash point 137 ± 0.00°C, cloud point 1.0 ± 0.00°C, pour point -0.4 ± 0.0°C, sulphur content 0.021 ± 0.01 ppm, kinematic viscosity 3.82 ± 0.0 mm2/s and specific gravity 0.8615 ± 0.0 g/cm3. The percentage yield of biodiesel was 89.12 ± 0.04%. Stearic acid methyl ester, a saturated ester, was dominant with percentage of 14.03% in the biodiesel produced. The yield of the oil is high enough and comparable with other oils that have been used for biodiesel production. It can be inferred that oil from Momordica balsamina is suitable for biodiesel production.

Open Access Original Research Article

Interpretation of High Resolution Aeromagnetic Data to Estimate the Curie Point Depth Isotherm of Parts of Middle Benue Trough, North-East, Nigeria

A. Aliyu, K. A. Salako, T. Adewumi, A. Mohammed

Physical Science International Journal, Page 1-9
DOI: 10.9734/PSIJ/2018/38651

This research work deals with estimation of Curie point depth isotherm using aeromagnetic data of part of middle Benue Trough, North-East, Nigeria. The study area lies within the Longitude 9ºE – 10ºE and Latitude 8ºN – 9.50ºN with an estimated total area of 18150km2. Regional/Residual separation was performed on the total magnetic intensity using polynomial fitting. The residual map was divided into fourteen spectral blocks and the log of spectral energies were plotted against frequency. Centroid depth and depth to top boundary obtained were used to estimate the Curie point depth isotherm which is the depth at which the crust and uppermost mantle magnetic materials cease to be magnetic as a result of increase in temperature as depth increases. The result shows that the Curie isotherm depth varies between 17.04km to 27.40 km with an average value of 22.5 km. Based on previous research works, the Curie point depth isotherm obtained from this study is a good source of geothermal potential.

Open Access Original Research Article

Investigation of Depolarization and Cross Polarization over Ku-band Satellite Links in a Guinea Savanna Location, Nigeria

O. M. Durodola, Ibrahim Aminu, J. S. Ojo, M. O. Ajewole

Physical Science International Journal, Page 1-9
DOI: 10.9734/PSIJ/2018/39940

In communication systems engineering, designers tend to optimize the channel capacity of radio links through frequency re-use by deploying dual independent orthogonally polarized channels in the same frequency band. Such frequency re-use techniques via linear or circular polarization are severely impaired by the interference of cross-polarized signals, because the energy from one polarization is transferred to the other orthogonal region. Depolarization effects on satellite links are described in terms of cross polar discrimination (XPD). The parameters mainly responsible for depolarization due to scattering by oblate spheroid raindrops at Ku-band can be estimated from satellite beacon footprint data. In this paper, data obtained from Ku-band, EUTELSALAT (W4/W7) at a frequency of 12.245 GHZ and elevation angle of 036° E over Jos, Nigeria (9.9565° N, 8.8583° E, 1258 m) were analyzed. One minute rain rate obtained from rapid response rain gauge was also analyzed alongside the beacon measurements. Consequently, the aforementioned data were applied to the ITU-R procedure in recommendations 618-12 to estimate XPD due to rain on earth satellite path over the study location. The results show positive values of XPD, the threshold of rain rate of 27 mm/h, while the threshold for co-polar attenuation was found to be 5.6 dB. Also, negative XPD values of about -120 dB obtained indicated that very high incidences of interference and cross-talks could occur in the region; and this could inhibit frequency re-use in the Guinea Savanna region of Nigeria. The overall results obtained provided useful models and thresholds values for radio communication planning in the region.