-
Antibiotics Resistance in Water Mediums: Background, Facts, and Trends
Djamel Ghernaout,
Noureddine Elboughdiri
Issue:
Volume 4, Issue 1, June 2020
Pages:
1-6
Received:
18 December 2019
Accepted:
25 December 2019
Published:
7 January 2020
DOI:
10.11648/j.ae.20200401.11
Downloads:
Views:
Abstract: From human and animal provenances, antibiotic-resistant microorganisms come into water mediums. Such bacteria are capable of diffusing their genes into water-indigenous microbes, which as well hold resistance genes. Conversely, several antibiotics from industrial sources spread in water mediums, greatly modifying microbial ecosystems. During the last decade, hazard evaluation protocols for antibiotics and resistant bacteria in water, founded on better programs for antibiotics discovery and antibiotic resistance microbial origin tracking, are more and more enhanced. Techniques to decrease resistant bacterial charge in wastewaters and the number of antimicrobial agents, in most cases originated in hospitals and farms, involve regulation of disinfection methods and running of wastewater and manure. For avoiding mixing human-originated and animal-originated microorganisms with ecological organisms, a procedure is more than recommended. This work reviews the facts and future trends of this new open and imposed field in dealing with domestic wastewater. It is vital to elevate efficient barrier measures such as membranes processes, like reverse osmosis and nanofiltration, avoiding the integration of resistant and pathogenic bacteria into nature. Techniques have to be developed for cheap and reliable: first, bacterial clones and resistance genes origin tracking; second, detection of antibiotics in water mediums; third, disinfection of water from antibiotic-resistant populations and the resistance gene pool, and elimination of antibiotics from wastewater; and fourth, prevention policies for mixing human–animal-originated and soil–water bacteria.
Abstract: From human and animal provenances, antibiotic-resistant microorganisms come into water mediums. Such bacteria are capable of diffusing their genes into water-indigenous microbes, which as well hold resistance genes. Conversely, several antibiotics from industrial sources spread in water mediums, greatly modifying microbial ecosystems. During the la...
Show More
-
Estimation of Surface Roughness of Aluminum Reinforced Metal Matrix Composites
Jimoh Olugbenga Hamed,
Ganiyu Ishola Agbaje,
Abdullahi Ikani Bakwo,
Bisola Abigail Olaniyi,
Ismail Olusegun Lawal,
Adekunle Benjamin Falade
Issue:
Volume 4, Issue 1, June 2020
Pages:
7-13
Received:
30 December 2019
Accepted:
9 January 2020
Published:
21 January 2020
DOI:
10.11648/j.ae.20200401.12
Downloads:
Views:
Abstract: There is a strong agitation from rocket designer for a highly reinforced metal matrix composites for rocket chamber to curtail the effect of high temperature and pressure from gaseous product of combustion process. This study has been designed to evaluate the surface roughness of an aluminum reinforced metal matrix composites produced by stir casting techniques at constant cutting speed of 1000 rpm, three (3) different feed rates at various aluminum weight ratio. Response surface methodology was adopted to formulate a surface roughness model in terms of metal matrix constituents such as aluminum, barite and zircon under three (3) different feed rate. The model adequacy was verified using analysis of variance. Also, the approach was used to optimize the effect of reinforced materials on surface roughness of the matrix composites. The increase in weight ratio of aluminum matrix reduces the surface roughness and vice versa. However, increase in barite, zircon weight ratios and feed rate increase the surface roughness. The optimum matrix chemical composition ratios of 0.9310, 0.0296, and 0.0394 for aluminum, barite, and zircon respectively with optimal desirability index of 0.903 shows the validity of the design. The F-values obtained at 95% confidence interval revealed that the selected model adequately represent the data for the matrix composites. Therefore, the study confirm the effectiveness of Response Surface Methodology as a tool in predicting surface roughness and provide materials with enhanced mechanical properties.
Abstract: There is a strong agitation from rocket designer for a highly reinforced metal matrix composites for rocket chamber to curtail the effect of high temperature and pressure from gaseous product of combustion process. This study has been designed to evaluate the surface roughness of an aluminum reinforced metal matrix composites produced by stir casti...
Show More
-
Effect of Bismuth Ratios on the Gamma Shielding Properties for NBR/Nano Silica Composites
Amal Abdel Razek El-Gamel,
Elham Mahmud Hegazi
Issue:
Volume 4, Issue 1, June 2020
Pages:
14-19
Received:
2 January 2020
Accepted:
8 January 2020
Published:
21 January 2020
DOI:
10.11648/j.ae.20200401.13
Downloads:
Views:
Abstract: The effect of the different ratios of bismuthon Nitrile Butadiene Rubber (NBR)/nano silica composite as shielding materials are studied in this study. And the study was carried on for gamma ray photon energies (0.3, 0.6, 1.25, 3 and 7) MeV obtained by (131Ir, 60Co and 137Cs) radioactive sources by using MCNP5, WINXCOM and Matlab. The numerical simulation results showed that, the shielding properties (Linear and mass attenuation coefficients, Transmission factors, Half value layer and radiation protection efficiency) of the composite materials increase with increase in the bismuth ratio and decreases with increase in energy. Also the results show that, Half-value layer (HVL) decrease with increase in the Bismuth ratio and increase with increase in gamma photon energy. It is found that the optimum concentration of Bismuth is 60%. The results confirm that rubber composites loaded with bismuth can act as an excellent gamma radiation shielding materials.
Abstract: The effect of the different ratios of bismuthon Nitrile Butadiene Rubber (NBR)/nano silica composite as shielding materials are studied in this study. And the study was carried on for gamma ray photon energies (0.3, 0.6, 1.25, 3 and 7) MeV obtained by (131Ir, 60Co and 137Cs) radioactive sources by using MCNP5, WINXCOM and Matlab. The numerical simu...
Show More
-
Phosphating and Accelerating Corrosion Behavior on Al-Si Coating of Hot Stamping 22MnB5 Steel
Issue:
Volume 4, Issue 1, June 2020
Pages:
20-26
Received:
2 April 2020
Accepted:
20 April 2020
Published:
4 June 2020
DOI:
10.11648/j.ae.20200401.14
Downloads:
Views:
Abstract: In order to study the relevant of corrosion resistance with hot treatment process condition, verify whether Al-Si alloy coating surface can be treated with zinc salt phosphating. It is prepared several different kinds of hot stamping Al-Si coating of 22MnB5 steel plates. The heating treatment temperature, holding time, thickness of coating and diffusion layer are discussed in this paper. Then phosphating to above plates which are obtained under several different hot treatment conditions. It is found that there exists some phosphating films on surface of several plates, such as No. 4, No. 5 and No. 9 sample, others have none. By scanning electron microscopy analysis method, morphology and microstructure of Al-Si coating and phosphating film are analyzed. By energy spectrum analysis method, all element contents are characterized. The content of Al element in the coating is decreased fom 87% to 8% through phosphating treatment. The content of Si element in the coating is decreased from 10% to below 1%. Because of corrosion of phosphating liquid, Al-Si alloy coating is broken at acid environment. Al is oxidated and become aluminum ion, Si is dissociated and deposited. With the decreasing of Al, anode region is oxidated. Because reduction in hydrogen concentration at cathode zone, pH become higher, when condition reachs to the solubility of zinc phosphate, the phosphating films appeared on surface metal material. The films element increasing, Zn is up to 20%, P is near to 9%, O is up to 34%, phosphating film crystal is main Zn3(PO4)2•4H2O and small amount of Zn2Fe(PO4)2•4H2O. In order to research corrosion resistance between phosphating film and Al-Si alloy coating, it is adopted CCT method to evaluate two passivation films. The result shows that phosphating film can not improve corrosion resistance of materials. On the other side, Al-Si alloy coating has better corrosion resistance, it can reduce corrosion rate of substrate. Through 50CCTs and 70CCTs, the sample NO. 8 shows excellent corrosion resistance. The result shows that the corrosion resistance of relatively good sample of heating treatment process condition is as follows: When heating treatment temperature is 930-950°C and holding time is 3-5min, hot dip plating and stamping of 22MnB5 steel with aluminum, silicon and other elements. It is obtained a continuous and complete coating, which toatal thickness is 42-52um.
Abstract: In order to study the relevant of corrosion resistance with hot treatment process condition, verify whether Al-Si alloy coating surface can be treated with zinc salt phosphating. It is prepared several different kinds of hot stamping Al-Si coating of 22MnB5 steel plates. The heating treatment temperature, holding time, thickness of coating and diff...
Show More
