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Search Results: 1 - 10 of 627742 matches for " M.N.B.;Eon "
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THE INFLUENCE OF NIOBIUM ON THE ACIDITY AND STRUCTURE OF GAMMA-ALUMINA-SUPPORTED VANADIUM OXIDES
Sathler, M.N.B.;Eon, J.G.;
Brazilian Journal of Chemical Engineering , 1998, DOI: 10.1590/S0104-66321998000200012
Abstract: gamma-alumina-supported niobium oxide was used as a support for vanadium oxides. the influence of the addition of niobium oxide was studied by looking for changes in the structure and acid-base character of superficial species. vanadium oxide was deposited using the continuous adsorption method; niobium oxide was impregnated using the incipient wetness method. the catalysts were characterized by xps, uv-visible and ir spectroscopy. catalytic tests were performed using propane oxidation reaction at 400oc. for coverage below the monolayer, both vanadium and niobium oxides were observed in slightly condensed superficial species. the presence of vanadium oxide on the support was found to increase the lewis acidity and create some bronsted acidity. higher catalytic activity and selectivity for propene were associated with vanadium oxides. the presence of niobium did not contribute to the modification of the chemical properties of superficial vanadium but did decrease the adsorption of vanadium on the alumina.
THE INFLUENCE OF NIOBIUM ON THE ACIDITY AND STRUCTURE OF GAMMA-ALUMINA-SUPPORTED VANADIUM OXIDES
Sathler M.N.B.,Eon J.G.
Brazilian Journal of Chemical Engineering , 1998,
Abstract: Gamma-alumina-supported niobium oxide was used as a support for vanadium oxides. The influence of the addition of niobium oxide was studied by looking for changes in the structure and acid-base character of superficial species. Vanadium oxide was deposited using the continuous adsorption method; niobium oxide was impregnated using the incipient wetness method. The catalysts were characterized by XPS, UV-visible and IR spectroscopy. Catalytic tests were performed using propane oxidation reaction at 400oC. For coverage below the monolayer, both vanadium and niobium oxides were observed in slightly condensed superficial species. The presence of vanadium oxide on the support was found to increase the Lewis acidity and create some Bronsted acidity. Higher catalytic activity and selectivity for propene were associated with vanadium oxides. The presence of niobium did not contribute to the modification of the chemical properties of superficial vanadium but did decrease the adsorption of vanadium on the alumina.
Health Risk of Escherichia coli O157:H7 in Drinking Water and Meat and Meat Products and Vegetables to Diarrhoeic Confirmed and Non-Confirmed HIV/AIDS Patients
B.O. Abong`o,M.N.B. Momba,N. Rodda
Journal of Applied Sciences , 2008,
Abstract: The current study explored the health risk of E. coli O157:H7 to diarrhoeic confirmed and non-confirmed HIV/AIDS patients due to their exposure to presumed ingestion of water, meat products and vegetables ostensibly contaminated with E. coli O157:H7. Strains of E. coli O157:H7 were isolated by enrichment culture and on Cefixime-Telurite Sorbitol MacConkey agar. Average counts of presumptive E. coli O157 were used for dose-response assessment. Probability of infection to confirmed and non-confirmed HIV/AIDS patients was 20 and 27% from meat and meat products, 21% and 15% from vegetables and 100% due to ingestion of 1500 mL person-1 day-1 of water. Drinking water had higher probability of transmitting E. coli O157:H7 infections than meat and meat products and vegetables. Probability of E. coli O157:H7 infections were high for confirmed HIV/AIDS patients than for non-confirmed patients. Water and foods consumed by HIV/AIDS patients should be safe of any microbial contaminants, these waters and foods should as well be investigated for other enteric pathogens to establish their safety.
Phosphorus and Nitrate Removal by Selected Wastewater Protozoa Isolates
O.B. Akpor,M.N.B. Momba,J. Okonkwo
Pakistan Journal of Biological Sciences , 2007,
Abstract: In the present study, the efficiency of ten selected wastewater protozoa in the removal of phosphorus and nitrogen and their effects on other physico-chemical parameters was investigated. Protozoa were isolated from the aerobic zone of Daasport wastewater treatment plant, in Pretoria, South Africa, using the modified Chalkey’s medium. The isolates were screened for nutrient removal ability in shake flasks, at laboratory temperatures for 96 h. During each sampling, aliquot samples were collected for the analysis of phosphorus, nitrate-nitrogen, Chemical Oxygen Demand (COD), Dissolved Oxygen (DO), pH, of the mixed liquor including the growth rate of the isolates using standard methods. The results indicated a steady increase in growth rate of the isolates and all the isolates used in this study showed some measure of phosphorus and nitrate removal ability. In the presence of the test protozoa isolates, an increase in COD and a decrease in DO were noted in the mixed liquor inoculated with the organisms, while the pH only increases slightly. This study revealed a significant correlation between growth rate and nutrient removal (R = -0.806, p<0.001 for phosphorus; R = -0.799, p<0.01 for nitrate). The present study has been able to show that certain protozoa isolates have the ability to biologically remove phosphorus and nitrate from effluent. Consequently, it would be necessary to identify what strains of protozoa are capable of excess phosphorus and nitrogen uptake for the treatment of wastewater.
Effect of Nutrient/Carbon Supplements on Biological Phosphate and Nitrate Uptake by Protozoan Isolates
O.B. Akpor,M.N.B. Momba,J. Okonkwo
Journal of Applied Sciences , 2008,
Abstract: This study was aimed at investigating the effect of nine different nutrient/carbon supplements in mixed liquor on nutrient uptake ability of three wastewater protozoan isolates, which have previously been screened for phosphate and nitrate uptake efficiency. The results revealed that over 50% of phosphate was removed in the presence of sodium acetate, glucose or sucrose. Similarly, nitrate uptake of over 60% was observed in the presence of sodium acetate, sodium succinate, glucose or sucrose. These trends were common in all the isolates. Chemical Oxygen Demand (COD) removal in the mixed liquor was only found to be significantly removed in mixed liquors that were supplemented with glucose, sucrose or sodium succinate. In the presence of sodium acetate, COD was observed to increase. The findings of this investigation have revealed that nutrient uptake and COD removal by the test protozoan isolates may be dependent primarily on the initial nutrient supplement in mixed liquor.
Protozoan Fauna and Abundance in Aeration Tanks of Three Municipal Wastewater Treatment Plants in the Eastern Cape Province of South Africa
M. Sibewu,M.N.B. Momba,A.L. Okoh
Journal of Applied Sciences , 2008,
Abstract: This study focuses on the assessment of the protozoan fauna and abundance in the mixed liquors of aeration tanks of the three municipal wastewater treatment plants located in Fort Beaufort, Dimbaza and East London in the Eastern Cape Province of South Africa and their implication to the production of effluents of good quality. The samples were collected between September and December 2005 and protozoa species were identified by direct microscopic observations at x400 magnification by comparison with existing protozoa gallery collections. A total of 68 protozoan genera made up of 44 ciliates, 16 flagellates and 8 others were identified in wastewater treatment plants. Although in all aerobic zones the average density of ciliates was 104 cells mL-1, which indicated that these plants were able to produce clear effluent of good quality, a better performance was found in Dimbaza and East London, which had total protozoan genera of 27 and 26, respectively.
Prevalence of Escherichia coli O157:H7 among Diarrhoeic HIV/AIDS Patients in the Eastern Cape Province-South Africa
B.O. Abong`o,M.N.B. Momba,V.K. Malakate,J.N. Mwambakana
Pakistan Journal of Biological Sciences , 2008,
Abstract: This study investigated the prevalence of Escherichia coli O157:H7 in the stool of confirmed and non-confirmed diarrhoeic HIV/AIDS patients. Escherichia coli O157:H7 was isolated by culture-based and immunomagnetic separation from three hundred and sixty stool swabs. Identification was by conventional IMViC, 20E API and molecular techniques. Confirmed and non-confirmed diarrhoeic HIV/AIDS patients had 56.5% (74/131) and 43.5% (57/131) respectively of E. coli O157:H7. Molecular results indicated that the prevalence of E. coli O157:H7 was 12.16% (9/74) and 8.77% (5/57) from stool swabs of confirmed and non-confirmed diarrhoeic HIV/AIDS patients. Antimicrobial resistance was higher for E. coli O157:H7 isolates from stools of confirmed HIV/AIDS than it was for non-confirmed HIV/AIDS patients. Escherichia coli O157:H7 might be a silent cause of diarrhoea in HIV/AIDS patients. It is recommended that HIV/AIDS patients with diarrhoea should be screened for E. coli O157:H7 and surveillance programmes for these bacteria should be established in both urban and rural areas of South Africa.
Desenvolvimento de um sistema de resfriamento e conserva??o de sêmen suíno
Roner, M.N.B.;Silva Filho, J.M.;Palhares, M.S.;Ziviani, M.;Nascimento, E.F.;Silva, I.J.;
Arquivo Brasileiro de Medicina Veterinária e Zootecnia , 2006, DOI: 10.1590/S0102-09352006000100012
Abstract: a container with controlled cooling rate from 37oc to 17 or 5oc was constructed for the preservation of boar semen. the container produced a cooling rate initially of -0.16oc/min for a final temperature of 17oc and of -0.17oc/min for a final temperature of 5oc. the cooling process, during cold shock temperatures (17oc - 8oc) was of -0.0049oc/min. the container temperature was stable for 53.58h at internal temperature of 17±1oc and for 43.32h at 5±1oc.
Optimization of welding parameters for weld penetration in FCAW
N.B. Mostafa,M.N. Khajavi
Journal of Achievements in Materials and Manufacturing Engineering , 2006,
Abstract: Purpose: This paper describes prediction of weld penetration as influenced by FCAW process parameters of welding current , arc voltage , nozzle-to-plate distance, electrode-to - work angle and welding speed . Optimization of these parameters to maximize weld penetration is also investigatedDesign/methodology/approach: It deals with the statistical technique of central composite rotatable design to develop a mathematical model for predicting weld penetration as a function of welding process parameters. The constrained optimization method is then applied to this model to optimize process parameters for maximizing weld penetrationFindings: The result obtained from the developed model indicates that the model predicts the weld penetration adequately. The optimization result also shows that weld penetration attains its maximum value when welding current, arc voltage , nozzle-to-plate distance and electrode-to-work angle are maximum and welding speed is minimumResearch limitations/implications: The statistical technique of developing a model for prediction of weld penetration is valid only within the specified limits of welding process parameters and hence maximization of penetration is also valid within these limits. This technique can be modified to include other parameters such as plate thickness affecting penetration.Practical implications: The statistical method for modeling and the optimization method used have found increasing applications in a variety of fields for investigation because through these methods research becomes economical , fast and versatile.Originality/value: The methods described in this paper for weld penetration prediction and optimization can eliminate the need for performing experiments on the basis of the conventional trial and error method which is time consuming and economically not justifiable.
PHYTOCHEMICAL SCREENING OF MALLOTUS PHILIPINESIS FOR ITS ANTIBACTERIAL ACTIVITY
M.N. Patani M.N,J. Jain,B.H. Marya,M.B. Patel M.B.
Journal of Global Pharma Technology , 2011, DOI: 10.1234/jgpt.v3i4.375
Abstract: Mallotus philippinensis Muell. Arg. belongs to the family Euphorbiaceae is also known as kamala powder which was extracte with methanol and ethyl acetate. Present study shows that both the extracts of kamala powder have good antibacterial activity, but when compared to Gram negative bacteria, Gram positive bacteria are more susceptible to the extracts. The mechanism of antibacterial action appears to be loss of control over cell membrane permeability.
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