ISSN 1556-6757


SJI 


 

 

 

 

 
 

Volume 1, Issue 2, 2007

 
 

Burn-Up Profiles for a New Beryllium Moderated Water Cooled Natural Uranium Reactor 

Robert B. Hayes
 

Abstract

A recently conceived nuclear reactor design is evaluated here for preliminary theoretical burn-up

characteristics which is intended to meet Global Nuclear Energy Partnership (GNEP) goals. This

reactor uses Natural Uranium (NU) metal as a single material fuel with beryllium moderation. The reactor also uses light water as a coolant. At constant power, the core reactivity initially

decreases followed by a long term increase within 1 month. The reactivity increase eventually

hits a maximum followed by a decline ending around a burn-up of over 30 GW-d when all the fuel

is analyzed as a single material. By considering a strategic power history profile, this property

can be exploited for advantage to allow power increases to eventually fall in the range of 100 to

500 MW for a once through cycle. Alternatively, by using a small fraction of the initial loading as

either a slightly enriched mix of uranium or reprocessed spent fuel from this reactor, overall

higher operating powers can be realized. By running the reactor for any moderate length of time

sufficient to create appreciable amounts of plutonium, the hyper breeding nature of the reactor

converts a large fraction of the isotope Pu-239 into Pu-240 supporting a proliferation resistant

nature of the design. By reprocessing the spent fuel without ever separating the plutonium from

the uranium, GNEP goals can be supported by mixing the spent fuel with natural or depleted

uranium. In this way, the reactor might be used in normal operations for transmutation of the long lived actinides.  Full Article



Studies on antimicrobial, antioxidant and phytochemical analysis of Urena lobata Leave extract 
Adeloye, O. Adewale, Akinpelu, A. David, Ogundaini, O. Abiodun, Obafemi, A. Craig
 

Abstract

The leaves extracts of Urena lobata L were examined for their antioxidant, antibacterial and antifungal activities. Preliminary evaluation of both the crude and the solvent fractions showed a broad spectrum of activity since the extracts inhibit the growth of both gram positive and gram negative bacterial isolates. The ethyl acetate and n-butanol fractions had a fast antioxidant reaction with DPPH solution, while the n-hexane and dichloromethane fractions gave no reaction. Three compounds were isolated from the ethyl acetate fraction and their structures determined, on the basis of spectroscopic data, to be kaempferol 1, quercetin 2, and 3-O-β-D-(6-O-trans-p coumaroyl)-α-L-glucopyranosyl-kaempferol 3 (tiliroside). The compounds showed strong antimicrobial activity against Escherichia coli, Bacillus subtilis, Klebsiella pneumoniae, Bacillus polyxyma and Candida albicans. The compounds also showed moderate to fast radical scavenging properties against DPPH radical. It was concluded that the isolated flavanoids may be part of the compounds responsible for the biological activity of Urena lobata leaf extract. This study therefore supports the traditional uses of the plant in the treatment of infectious diseases.

Full Article


 

A Simple Laboratory Experiment for the Measurement of Single Phase Permeability
Ali R. Zand, Yuri Sikorski, Matthew S. Sanders, Homayun K. Navaz
 

Abstract

A simple experiment for measuring single-phase permeability of fully saturated porous medium

is introduced. The experiment utilizes radial flow of a non-volatile wetting fluid through a porous

medium such as ceramic tile, concrete or sand. The radial position of flow front is measured as

a function of time and the collected data are analyzed using Darcy’s Law to determine the

permeability. In addition, the phenomenon of the multiphase flow through the medium with a

broad pore size distribution is demonstrated. Full Article



 

Composition of two Lorentz boosts through spatial and space-time rotations
Chandru Iyer and G. M. Prabhu
 

Abstract

We develop the Lorentz matrix in two-dimensional space by two methods consisting of three

parameters each. By comparing the two and utilizing the natural invariant properties of the

elements, we evolve the composition of two Lorentz boosts. The development specifies how to

switch from one three-parameter set to the other. A numerical tool to combine two planar boosts

is provided. We extend the method to three spatial dimensions by confining the boosts to a plane.Thus we show, without assuming the existence of a four-dimensional continuum, that the ordered composition of two Lorentz boosts in three-dimensional space yields a Lorentz boost. Full Article 




The Stability of an Inviscid Liquid Sheet Containing Vapor Bubbles
Layachi Hadji and Willard Schreiber

 

Abstract

The development of a liquid spray exiting a nozzle begins with the breakup of a liquid jet or sheet injected into a gas. The presence of vapor bubbles in a liquid jet can modify the instabilities, such as the Kelvin-Helmholtz interface instability, which causes a liquid jet or sheet to break up into a dispersion of small liquid droplets. A previously derived model is used in the present paper to investigate the influence of the presence of bubbles on the Kelvin-Helmholtz instability of an inviscid liquid sheet. It is predicted that the presence of bubbles would yield smaller liquid droplets.  Full Article 




Can We Be More Efficient in Oil and Gas Exploitation? A Review of the Shortcomings of Recovery Factor and the Need for an Open Worldwide Production Database
Gioia Falcone, Bob Harrison, Catalin Teodoriu

 

Abstract

This paper critically reviews the concept of recovery factor (RF) of oil and gas fields. Although this

simple parameter is used throughout the oil and gas industry, it is subject to misunderstanding

and misuse. Besides changing continually through the producing life of a field, the estimate of RF is affected by geological uncertainty, inappropriate reserves reporting, technological

shortcomings, commercial practices and political decisions. At present, the information necessary to fully evaluate RF is not unequivocally determined, audited or reported, which makes it impossible to produce consistent global field statistics. Based on the authors’ experience, the

paper outlines the shortcomings of RF and suggests how they may be overcome. To promote

clarity and transparency in RF calculations, a template for an open worldwide production

database is proposed. Full Article