Three-Dimensional Calculation of Contaminant Transport in Groundwater at a Dover AFB Site

Macroscale rate-limited sorption modeling was tested using a production transport code, the GMS/FEMWATER ground-water modeling package. The code (Version 1.1 of FEMWATER. dated 1 August 1995) was applied to a 3D conceptual model developed from a field site at Dover AFB, DE. A simulation was performed of a 200 hour contaminant injection pulse followed by clean water flushing. A moment analysis performed on the resulting breakthrough curve validated code self-consistency. Another injection pulse simulation showed that retardation temporally delays the breakthrough peak. Transport simulations of pulsed clean water pumping of the test cell with a prescribed initial contaminant distribution demonstrated both tailing and rebound without any additional microscale modeling. In comparison with both previous numerical solutions and the actual field data from the Dover AFB test site, FEMWATER has demonstrated high numerical dispersivity. For an initial contaminant distribution corresponding to the field data, the FEMWATER breakthrough curve was much flatter than the experimental result, failing to capture the plug-like elution of the field site

Comparison of homotopy analysis method and homotopy-perturbation method for purely nonlinear fin-type problems

In this paper, the homotopy analysis method (HAM) is compared with the homotopy-perturbation method (HPM) and the Adomian decomposition method (ADM) to determine the temperature distribution of a straight rectangular fin with power-law temperature dependent surface heat flux. Comparisons of the results obtained by the HAM with that obtained by the ADM and HPM suggest that both the HPM and ADM are special case of the HAM

Isolation and Characterization of the Endophytic N2 – Fixing Bacterium, Acetobacter Diazotrophicus aAssociated with Sugarcane Plants

Acetobacter  diazotrophicus is an obligate endophytic N2- fixing bacterium mainly associated with sugarcane and other sugar-rich plants that are propagated vegetatively (Kirchhof et al., 1998). This bacterium does not survive in soil or in weeds found in cane fields (Dobereiner, 1995) ). The presence of this endophyte within the tissues of sugarcane plants no doubt supplements the N-nutrition of the crop. This plants, preliminary work, thus attempts, for the first time, to isolate and characterize endophytes within the tissues of sugarcane plants grown in Kenana Sugar Company

Effect of Temperature on in vitro Survival of some Bradyrhizobium Strains

Evaluating Rhizobium survival in inoculants exposed to high temperature may be considered the first stage in identifying potential inoculant strains that would withstand temperature stress on inoculated seeds in the field. High temperatures may adversely affect the survival of Rhizobium in packaged inoculants during storage and inoculation (Somasegaran et al., 1984), and the viability of rhizobia in inoculants may be lost in a few weeks at temperatures of 350C or higher (Smith, 1987). Low storage temperature, however, is not always better than room temperature, as some slow growing bradyrhizobia were found to survive better at 260C than at 40C (Vincent, 1982). Soil temperature is also an important environmental variable that affects general biological activity. Nodulation and N2-fixation were observed under a wide range of temperatures with an optimum range between 20 and 300C. Elevated temperatures affect nodule initiation and development in temperate legumes, whereas, in tropical legumes it is mainly N2 fixation efficiency that is affected (Somasegaran et al., 1984). Temperature changes affect the competitive ability of Rhizobium strains and there are also specific temperature-sensitive Rhizobium legume combinations e.g. R. Legumino- sarum biovar-trifolii that forms nodules with Trifolium subterranium (Lewis-Henderson and Djordjevic, 1991(

Optimal Tuning of PD controllers using Modified Artificial Bee Colony Algorithm

This paper presents an investigation of PD controller tuning using a modified artificial bee colony algorithm (MABC). The main purpose of this work is to apply and investigates the performance of MABC in tuning the PD controller of single link manipulator system (SLMS) in comparison with the original ABC. The objective of the MABC algorithm is to minimize the error by using mean square error (MSE) as an objective function. The proposed algorithm has also been tested in three benchmark functions with different dimensions to checked the robustness of the algorithm in different problems surface. The result shows that the MABC able to tune the controller to their best optimum value

EXTRACTION OF PHENOLIC COMPOUNDS AS ANTIOXIDANTS FROM SOME PLANTS AND THEIR CYTOTOXIC ACTIVITY AGAINST BREAST CANCER CELL LINE

Objective: The objective of the study was to study the antioxidants and cytotoxic activities of phenolic extracts of some plants against breast cancer and normal cell lines.Methods: Phenolics were extracted from different parts of some plants (15) such as seeds, fruits, leaves, and rhizomes using methanol: ethanol: HCl: Distilled water at a ratio 50:29:1:20 (v:v:v:v). The contents of phenolics and flavonoids were estimated using gallic acid and quercetin as standards, respectively. The antioxidant activity was determined by 2,2ˋ-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging assay. Phenolic flavonoids were partially purified by adsorption chromatography using a silica gel column from selected plants and assayed their cytotoxic activity against breast cancer cell line Michigan Cancer Foundation-7 (MCF-7) and a normal cell line of non-tumorigenic fetal hepatic cell line (WRL-68).Results: The Cinnamomum zeylanicum extract had the highest phenolic and flavonoid contents were followed by Lawsonia inermis, Citrullus colocynthis, Syzygium aromaticum, Peganum nigrum, and Phoenix dactylifera. The antioxidant activity of Curcuma longa, P. dactylifera, C. colocynthis, Solanum melongena, and C. zeylanicum extracts had the highest ability to scavenge the free radicals. The acetone fraction of P. dactylifera and C. colocynthis extracts had the minimum inhibition dose that kills 50% of cells inhibitory concentration 50 values 156.91 μg and 1055.06 μg against MCF-7 and 372.86 μg and 153.8 μg against WRL-68, respectively. While the S. melongena extract had less effect on both cell lines.Conclusions: Phenolics as antioxidant substances had moderate or variable effectiveness on normal and cancer cell lines, and the highest concentrations were cancerous poison impact may be on normal cells over than cancer cells