Open Access Data Article

Gross Alpha and Beta Activity Concentrations in Surface Water Supplies from Mining Areas of Plateau State, Nigeria and Estimation of Infants and Adults Annual Committed Effective Dose

W. E. Mangset, A. O. Solomon, D. L. Christopher, E. E. Ike, R. A. Onoja, S. P. Mallam

Physical Science International Journal, Page 241-254
DOI: 10.9734/PSIJ/2015/14992

A radiological characteristic of surface waters of the mining areas of Plateau State, Nigeria covered by the Naraguta Topographical sheet 168 was carried out in the month of March 2012.  For this purpose forty – eight (48) surface water samples were collected from 25 mine ponds and 23 streams.  Analysis included gross alpha and gross beta activities using MPC – 2000 – DP and estimation of committed effective Dose to the different age groups of the general public.  The results obtained showed that the gross alpha activities ranged from (0.047±0.010 – 6.640±0.032)Bq/l with a geometric mean of 0.410±0.016Bq/l for mine ponds samples while the gross beta activities for mine ponds ranged from (0.001±0.009-6.680±0.039)Bq/l with a geometric mean of 0.125±0.010Bq/l. Also the gross alpha activities for stream water samples ranged from (0.140±0.011 – 4.310±0.013)Bq/l with a geometric mean of 0.642 ±0.015Bq/l and the gross beta activities for stream samples ranged from (0.040±0.001 – 1.170±0.018)Bq/l with a geometric mean of 0.250±0.008Bq/l.  The annual committed effective dose for all age groups was calculated and they showed elevated values above the ICRP acceptable standard of 0.1mSv/yr.  This implies that infants and children who are more susceptible to radiation dose through water ingestion may be exposed to high radiation health risk.

 

Open Access Original Research Article

Control Gain and Cost of Pinning Control for BA Scale-Free Networks

Zhengzhong Yuan, Jianping Cai

Physical Science International Journal, Page 223-229
DOI: 10.9734/PSIJ/2015/14574

This paper investigates the pinning control strategy of BA scale-free network through numerical analysis. A new cost function is defined to measure the cost of pinning control. Compared with the control gain and the cost of pinning nodes with smallest degrees or biggest degrees, an interesting result is that a smaller control gain and a lower cost are achieved by using the control scheme of pinning nodes with smallest degrees. Moreover, there is a minimal control cost by pinning nodes with smallest degrees and biggest degrees, respectively. The number of controllers by pinning nodes with smallest degrees is considered finally.

 

Open Access Original Research Article

New Metrology Approach for Single Molecular Device: Probing of Molecular Energy Gap by Electrical and Optical Measurements

V. Andrei Pakoulev, Tatjana N. Kopylova, Yu. Sergey Nikonov, N. Evgeny Telminov, Vladimir Burtman

Physical Science International Journal, Page 230-240
DOI: 10.9734/PSIJ/2015/14438

We report on electrical and optical measurements to probe the energy gap in single molecular devices. The closeness of energy of the high occupied molecular orbital - low unoccupied molecular orbital (HOMO-LUMO) energy gap was detected by electric (ΦBΣ) and optic measurements (Δo), ΦBΣ ≈ Δo. The ‘electrical gap’, ΦBΣ, consists of sum of two barriers, ΦBLUMO and ΦBHOMO, for tunneling of electrons and holes through molecular barrier correspondingly, in devices with a different pair of electrodes at low biases and difference in work function, ΔWF, between these metal electrodes:ΦBΣ = ΦBLUMO + ΦBHOMO+ ΔWF. We fabricated and tested two devices with a pair of gold (Au) and aluminum (Al) electrodes to find ΦBHOMO (ΦBAu) and ΦBLUMO (ΦBAl) using Simmons tunneling model. The symbols ΦBLUMO and ΦBHOMO signify energy difference between HOMO and LUMO levels in a molecular system with respect to the Au and Al electrode’s Fermi level. Comparison of ΦBΣ and Δo can identify presence of electrically active molecules between electrodes in nanoscale devices.

Open Access Original Research Article

A First Order Phase Transition and Self-organizing States in Single-domain Ferromagnet

V. V. Nietz

Physical Science International Journal, Page 255-266
DOI: 10.9734/PSIJ/2015/14982

Analytical consideration of uni-axial single-domain ferromagnet during the first order phase transition induced by a magnetic field is performed. Field is directed along the symmetry axis antiparallel to initial magnetization direction. For samples of the flat shape, besides the known change of the magnetization direction on 180º, at definite relations between values of magnetic field, the magnetization and the anisotropy of a crystall, there is continuous spectrum of states with intermediate magnetization directions. In these states, a precession frequency ω = 0. For samples of spherical shape, a process of the phase transition does not depend on the demagnetization field. At addition action of high frequency field perpendicular to the main magnetic field, there are dynamic equilibrium states, i.e. "self-organizing states" of ferromagnet, when the entropy increase connected with dissipation is compensated by the negative entropy flow due to the periodic field. It is shown that under these conditions, by varying the frequency of the periodic field, we can control the self-organising system, i.e. decrease or increase the system energy and, correspondingly, change the direction of magnetisation in ferromagnet.

 

Open Access Original Research Article

A Natural Solution to the Dark Energy Problem

Man Ho Chan

Physical Science International Journal, Page 267-275
DOI: 10.9734/PSIJ/2015/14201

Recent observations indicate that the acceleration of our universe expansion is slowing down, which challenge the standard CDM model. In this article, we show that the existence of particles with imaginary energy density can explain the observed slowing down acceleration and provide a complete solution to the origin of dark energy. This model can give good agreements with observational constraints by 28 data from supernovae between redshift z = 0:07 - 2:3.

Open Access Review Article

A Review of Corrosion in Agricultural Industries

Makanjuola Oki, Paul. A. L. Anawe

Physical Science International Journal, Page 216-222
DOI: 10.9734/PSIJ/2015/14847

Corrosion is ubiquitous and ravages all sectors of world economies of which agricultural industries are not immune. Techniques abound to stop corrosion theoretically and practically however, human errors and over enthusiastic application of available methods of protection have reduced their applications to practical reduction of corrosion rates of materials of construction. This review highlights chemicals and agricultural wastes which enhance corrosion rates of materials of construction and practical ways of reducing their effects.