Open Access Commentary

Discussion of a Modelling Study of Coastal Inundation Induced by Storm Surge, Sea-level Rise, and Subsidence in the Gulf of Mexico: The US Average Tide Gauge is not Accelerating Consistently with the Worldwide Average

A. Parker, C. Ollier

Physical Science International Journal, Page 49-64
DOI: 10.9734/PSIJ/2015/17461

Yang et al. [1] assume sea level rise induced by global warming is real, and that sea levels may rise by 1 meter by 2100. They then go on to derive ecological conclusions from these assumptions.  There is of course no foundation for the ecological speculation if the basic assumptions are false. Real tide gauge data show that sea level is rising slowly, both worldwide and the US, without any acceleration. As shown in this comment, the last 3 NOAA surveys of sea level rises, compiled in 1999, 2006 and 2013, indicate that the rate of sea level rise is reducing from one survey to the next.

 

Open Access Original Research Article

EMF Power Absorption in Bone and Bone Marrow: Mathematical Model

Mona A. El Naggar

Physical Science International Journal, Page 11-19
DOI: 10.9734/PSIJ/2015/17210

A deterministic mathematical method is adopted to evaluate the power absorption due to EMF radiation in bone and bone marrow. The specific absorption rate (SAR), in both anatomic structures, is computed according to the present mathematical model, is represented spatially in the bone-marrow-bone layers under study. The effect of exposure to electric field of strengths ranging from 1 V/m to 1 kV/m is investigated for a wide frequency spectrum in each layer of the proposed model. The frequency dependence of the SAR, through these layers, is illustrated for frequencies ranging from 1 kHz to1GHz. The present results are in agreement with international safety standards for applied filed strengths of maximum value; 10 V/m for bone and 100 V/m for bone marrow. Moreover the present model shows that oblique incidence results in higher SAR values than with normal incidence, highly evident for low frequency.

Aim: Evaluation of the EMF power absorption and distribution, in bone and bone marrow, due to EMF radiation.

Study Design: Mathematical analysis followed by computer simulation of the problem.

Place and Duration of Study: Department of Engineering Physics & Math., Faculty of Engineering, Cairo University, between May 2014 and Dec.2015.

Methodology: The author employs a bone-marrow-bone model to investigate the effect of incident EMF. The equations governing the total electric and magnetic field distributions in each layer are deduced, considering its biological electromagnetic properties. The model is simulated by a computer program using Maple V. The computed values of specific absorption rate (SAR) in bone and bone marrow are graphically represented to show spatial distribution in each one. The exposure to electric field of strength ranging from 1V/m to 1kV/m is investigated using the proposed method. The frequency dependence of the SAR through the bone-marrow-bone layers under study is illustrated for a frequency range of 1 kHz-1GHz.

Results: Electromagnetic radiation of 1 MHz-10MHz induce absorbed power within the safety limits for all applied field strengths. The 1 GHz incident radiation induces SAR values higher than permissible ranges for field strengths above 400V/m whereas the same occurs for a low frequency range at 100 V/m. Moreover, the present results are in agreement with international safety standards for applied filed strengths till 10 V/m for bone and till 100 V/m for bone marrow, covering the applied frequencies (1 kHz -1 GHz). Except for exposure to electric field of strength higher than 100 V/m, the SAR acquired by the bone marrow is within the safety levels.

Conclusion: The results obtained are in agreement with international safety standards for filed strengths of maximum value 10 V/m for bone and 100 V/m for bone marrow. Oblique incidence results in higher SAR values than normal incidence, especially for low frequency (1 kHz).

 

Open Access Original Research Article

Effect of Gamma Radiation in Undoped SnO2 Thin Films

A. F. Maged, L. A. Nada, M. Amin

Physical Science International Journal, Page 20-27
DOI: 10.9734/PSIJ/2015/17250

This paper was reported on study the effect of gamma radiation on nanoporous SnO2 electrodes for dye-sensitized solar cells. Structural, optical and electrical properties were studied. The refractive index was decreased with the increase in gamma radiation. The resistivity of thin films was decreased about 40% with the increase of gamma radiation at 659 nm film thicknesses. The mobility and carrier concentration were increased with the increase of gamma dose at 659 nm film thickness.

 

Open Access Original Research Article

Design of a Novel Shield of Nuclear Medicine with New Alloy

Mahdi Haghighatafshar, Peyman Rezaie, Mohammad Atefi, Farshid Gheisari, Mohammad Ali Okhovat

Physical Science International Journal, Page 28-32
DOI: 10.9734/PSIJ/2015/16603

Background: Protecting patients and healthcare workers from harmful ionizing radiation, has been an important concern. Due to high efficacy, for many years, lead has been used as the best choice for this purpose. Lead has been always considered as a traditional choice to protect both workers and patients from any unnecessary exposure to ionizing radiation. Recently there has been a great deal of concern expressed about the toxicity of lead. The aim of this study was to design a novel shield for nuclear medicine with different alloy as a desired replacement for traditional lead base protectors.

Methods: A combination of Cadmium, Bismuth, Lead (only 15%) and Copper were selected by studying metals and calculation of metals’ HVL by Monte Carlo N-Particle Transport Code (MCNP4C) modeling.

Results: The results of the tests were evaluated and determined that the designed shield, considerably reduces the received dose by a thousand times and this alloy with 2 mm thickness is equivalent to that of a 20 mm traditional lead shield.

Conclusion: This novel shield that is produced with lesser lead in this study is considerably safer and offers effective protection in diagnostic energy ranges and may replace the traditional lead-based protectors.

 

Open Access Original Research Article

Performance Evaluation of FSO System with MIMO Technique in Different Operating Environments

Mohamed B. El-Mashade, Moustafa H. Aly, Ahmed H. Toeima

Physical Science International Journal, Page 33-48
DOI: 10.9734/PSIJ/2015/17212

Free Space Optical (FSO) communication is a promising solution for the need of very high data rate point-to-point communications. However, the wireless optical communications in the atmosphere were influenced by atmospheric absorption, scattering and turbulence which lead to signal attenuation and result in considerable degradation of the system performance. Since the average transmitted power is limited owing to the requirements for safety of human eye, prudent measures must be taken into account in the design of the basic units of such type of communication systems in order to exploit its great benefits under all weather conditions.

In this paper, our objective is to design a MIMO-FSO link and analyze its performance in difficult background conditions. The achievable performance improvements, including received power levels, bit error rate (BER) and Q-factor, are demonstrated in the presence of atmospheric attenuation. Our numerical results are obtained for SISO as well as MIMO system with elements varying from 2 to 4. For each one of these schemes, along with the evaluation of received power, Q-factor, and BER, the system performance is predicted through the analysis of the eye diagram. It was found that, the received power is increased by approximately 12 dB in the case of MIMO system with 4 elements when the operating environment is slightly foggy. On the other hand, higher Q-factor, 64.7, and lower BER are achieved by the same system in the case where the background is ideal.   

Open Access Review Article

The Prospect of Nuclear Power after Fukushima Daiichi Accident in an Emerging Global Energy Crises

D. I. Igwesi

Physical Science International Journal, Page 1-10
DOI: 10.9734/PSIJ/2015/17057

The purpose of this paper is to review the effect of Fukushima Daiichi accident on world nuclear power and the progressive growth the industrial had enjoyed from April, 2011 till January, 2015. The paper specifically considers the new reactors connected to the grid within the period, the ongoing constructions of new power plants worldwide licenced after the accident and stringent safety measures taken by the International Atomic Energy Agency (IAEA) to routinely check the existing reactors and incorporate during the design of new one in a bit to forestall future occurrences. The study remarkably showed that nuclear power industry has risen above the Fukushima Daiichi accident with an addition capacity of 18, 053 MW(e) generated from 21 nuclear reactors connected to the grid between April, 2011 and January, 2015. Moreover, 24 new reactors of combined capacity 22, 581 MW(e) licenced within the period are under construction. These new reactors are mostly advanced pressurized water reactors (PWR) of improved safety system. This marginal shift from generation II to generations III and III+ reactors with passive safety systems shows a confirmation of positive step towards achieving safe and reliable nuclear energy. From the study, it could be reliably assert that the contribution of nuclear energy to world energy mix is not debatable and more importantly, nuclear energy still remains safe even in the Fukushima challenges, cost-effective and very reliable source of base load power that will play a pivotal role in both global economic prosperity and a clean environment.