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Experimental and theoretical studies on the protective effect of a biomass corrosion inhibitor (vigna radiata) on mild steel in acidic medium
Get PDFThis article contains table and figuresThe scrutiny of the impeding properties of vigna radiata (VR) on mild steel corrosion in sour environs (1 M HCl and 0.5 M H2SO4) was done by means of gravimetric, electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization methods (PDP). Polarization findings revealed that VR retarded the corrosion process in a mixed-mode manner. Adsorption of the active components of VR was found to be in line with Langmuir adsorption isotherm. The obtained PDP result was complemented by the EIS findings. Scanning electron microscopy (SEM), atomic force microscopy (AFM) and the theoretical technique was used to complement the results.World Bank Africa Centres of Excellence for Impact (ACE Impact) Project (NUC/ES/507/ 1/304) and National Natural Science Fund of China under contract No. 51871227 and No. 51650110506
Design and fabrication of a portable obstruction detection device for visually impaired persons
No full textThe article contains figures and tablesThe cow-horned cased Obstruction Detection Device (ODD), powered by 9V battery, is designed for visually impaired persons. It is constructed using two HC-SR04 ultrasound sensors for front obstacle and depression detections. The device detects an obstacle by emitting ultrasonic sound that hits the interface and interprets the echo. The emission of this sound is triggered by the PIC16F877A microcontroller programmed to send out feedback to the user’s earphone in form of a musical note peculiar to the range of distance of the obstacle. The device is integrated with Radio Frequency (RF) Module that locates the device when misplaced. This Module has LM555 timer that regulates the signal emitted by the misplaced device. The device is incorporated with a Light Dependent Resistor (LDR) that detects any change in illumination. This project designed and fabricated a cheap locally cased ODD with comparative advantages of informing the visually impaired of the range of distance and position of the obstacle and the location of a misplaced device
Hydrocarbon degradation potential by soil bacteria using vapour-phase and spectrophotometric methods
Get PDFThis article has tables and figuresCrude and refined oil contamination is inevitable is oil producing communities. The attendant effects of environmental degradation and low crop yield had remain a burden to mankind. Soils from oil polluted areas were assessed microbiologically using vapour phase and spectrophotometric methods. This study assessed bacteria with capabilities of utilizing diesel, toluene and kerosene as sole source of carbon for growth. Culturing and sub-culturing was done in nutrient agar and Bushnell Haas Agar (BHA).Micrococcus luteus, Enterococcus fecalis, Bacillus subtilis, Bacillus cereus and Staphylococcus aureus were the predominant microorganisms isolated from the samples locations. The standard plate counts for each source of sample include FA1 (2.80 × 106), FA2 (1.50 ×106), MW1 (3.80 × 106), MW2 (1.7 × 106), FS1 (1.22 × 107), and FS2 (1.30 × 103). Spectrophotometric reading showed visible growth/turbidity in tubes labeled MW1bT, MW1bK, MW1bdD, FS2bD, and FS2bT. The growth of bacteria was observed from visible increase of turbidity and was enumerate by CFU/ml. Among isolates, Bacillus subtilis exhibited relatively higher ability to grow on the three hydrocarbons. Microorganisms have metabolic capabilities to utilize the carbon compounds and degrade them to innocuous by-products. These abilities can be targeted for bioremediation purposes
Parametric optimization of synthesis of silver nanoparticles from Mangifera indica and Prunus dulcis extracts and their antibacterial activity
Get PDFIt is an original research paper with tables and figuresOptimization of process parameters is crucial to the deployment of nanotechnology as a competitive source of novel materials to many fields. The present study has lent credence to the simplicity, environmental friendly, cost effective and quick potentials of using plant extracts as source of capping and stabilization agents in the synthesis of silver nanoparticles (AgNPs). Aqueous leaf extracts of Mangifera indica and Prunus dulcis were used in synthesis of silver nanoparticles. The study was designed with Box Behnken Design (Minitab® 17) to optimize temperature (25 – 35°C), pH (6 – 8) and time of reaction (6 – 24hours). Fifteen runs were obtained for each sample which determined the value of each parameter used for the synthesis. Results obtained were subjected to Response Optimizer (Minitab® 17) which predicted optimum conditions for synthesis of silver nanoparticles as 25°C at pH 8 and 10.24 hours with predicted maximum yield of 2.53 for Prunus dulcis. However, the actual yield of silver nanoparticles under these conditions was 2.64. For Mangifera indica leaf extract, the predicted optimum conditions were 31.4°C at pH of 8.0 and 9.39 hours with predicted maximum yield of 2.55. Nevertheless, the actual yield under the optimum conditions was 2.61. Results show that Prunus dulcis extract has relatively higher potential yield for silver nanoparticles than Mangifera indica extracts. UV-Vis spectrophotometer showed that the absorbance for synthesized silver nanoparticles using both plant extracts peaked between 400 – 430nm. Silver nanoparticles from both plants showed activity against Bacillus subtilis and Pseudomonas aeruginosa, though B. subtilis was more sensitive. However, silver nanoparticle from Prunus dulcis was less effective against the bacteria
Theoretical studies of transport and surface properties of liquid Fe-Mn and Fe-Co alloys
Get PDFThis thesis is for the award of Master of Science (MSc.) in Solid State PhysicsTransport and surface properties of liquid Fe−Mn and Fe−Co alloys were computed using the self-association model in conjunction with a model based on the hard sphere theory, the model of Moelwyn-Hughes and a statistical mechanical approach. Using the self-association model, the model parameters were determined from the experimental thermodynamic data at 1863 K. These model parameters were then used to compute the concentration-concentration fluctuations at the long wavelength limit ((0)), short range order parameter (1), mutual diffusivity, viscosity, surface concentration, surface tension and surface (0) for the two alloys at 1863 K. Results obtained show that Fe−Mn alloy with low tendency of homocoordination exhibits ideal mixing below 0.25 and above 0.88 atomic fractions of iron. On the other hand, Fe−Co alloy shows ideal mixing property below 0.20 and above 0.88 atomic fractions of iron, homocoordination between 0.20 and 0.70 atomic fractions of iron (Fe) and weak ordering between 0.70 and 0.90 atomic fractions of iron (Fe). Throughout the entire concentration range, diffusion-related activities as reflected by mutual diffusivities are higher in Fe−Mn alloy than in Fe−Co alloy. The viscosities of the two liquid alloys exhibit negative deviations from Arrhenius’ law, with the negative deviation being more pronounced in the Fe−Co alloy. Calculations also indicate that more Mn-atoms segregate at the surface of Fe−Mn alloy whereas nearly equal concentrations of Fe-atoms and Co-atoms are at the surface of Fe−Co alloy. These observations possibly suggest that more Fe-atoms are present at the surface of Fe−Co alloy than that of Fe−Mn alloy. The surface tension of Fe−Mn alloy increases throughout the entire concentration range while for Fe−Co alloy, it initially decreases to around 0.59 atomic fraction of iron (Fe) before it rises rapidly. The results from the computation of surface concentration-concentration fluctuations at the long wavelength limit corroborate the results from bulk properties calculations
Experimental and DFT evaluation of adsorption and inhibitive properties of Moringa oliefera extract on mild steel corrosion in acidic media
No full textThis is an original article with tables and figuresThe corrosion response of mild steel in 0.5 M H2SO4 acid solution in the presence of Moringer oliefera (MO) leaf extract was investigated using gravimetric, electrochemical, and DFT techniques. Gravimetric results indicate that MO exhibits a high inhibition value up to 93.0% when the concentration was 1.5 g/L. Inhibition value in general increased with an increase in concentration of the extracts but decreased with prolonged exposure time and temperature. Analysis of polarization curves indicated that MO extract acted as mixed-type inhibitors. The adsorption process of MO on a mild steel surface in the acid solution fitted the Langmuir isotherm. GC/MS analysis of MO extract revealed the presence of more than 29 active constituents including 9,12-Octadecadienoic acid (Z, Z) methyl ester (28.55%); n-Hexadecanoic acid (11.24%); 9,12,15-Octadecatrienoic acid methyl ester (9.31%), Benzeneacetonitrile, 4-hydroxy-(6.32%),2-Furancarboxaldehyde,5-(hydroxymethyl)-(5.6%), Heptadecane (4.85%). Quantum chemical calculations were applied on some of the identified constituents to assess their adsorbability on the mild steel surface and the result revealed remarkable high interaction energies.World Bank Africa Centers of Excellence for Impact (Ace Impact) project (NUC/ES/507/1/304
Women farmers use of indigenous knowledge in land and water management for climate change adaptation in flood-plain agricultural areas of Imo State, Nigeria
No full textThis article contains tablesThis study was carried out to analyze indigenous knowledge practices employed by women farmers for climate change adaptation and mitigation in Imo State, Nigeria. A total of 360 women farmers was randomly selected from 7 flood plain areas of the State. Questionnaire and oral interview were used to elicit information from the respondents. Percentages, mean
and standard deviation were used to analyze data collected. Results showed the indigenous land and water management practices to include ; mulching (88.8%), use of mounds (80.5%), crop rotation (97.2%), soil fertilization (81.6%), conservation agriculture (97.2%), construction of infiltration pits (83.3%), construction of wells and basins for water storage (94.4%), terrace building (96.9%), planting mangrove trees (92.7%), use of sand bags against erosion (96.6%) among others. The high mean (M) response below showed the benefits of use of indigenous knowledge in land and water management to include; enhanced agricultural productivity (M=3.64), reduced water stress (M=3.25), improve soil air and water quality (M=2.86), improves soil organic matter content (M=2.95), increase soil moisture content (M=2.90), reduces erosion menace in farm (M=2.92) and others. The following challenges were faced – high transaction cost (M=3.04), land tenure problems (M=3.95), insecurity of rights to land (M=3.35), low level of income (M=3.67), lack of education and training (M=3.55) among other challenges. Extension training of women farmers be vigorously pursued to educate and enlighten the rural agricultural population
Environmental impact of palm oil mill effluent and its management through biotechnological approaches
Get PDFThis is a review articleGlobally, palm oil production is on the increase and the pollution caused by waste materials from the palm oil mills has become a major environmental concern. However, not much has been said about the negative effects of such a huge industry. This report reviews the environmental impacts of palm oil mill effluents generated from oil palm processing and how they can be efficiently managed through biotechnological tools. The processing of oil palm generates three (3) major waste streams including gaseous (pollutant gases), liquid (palm oil mill effluent, POME) and solid (palm press fibre, chaff, palm kernel shell and empty fruit bunch) wastes. POME has been the most problematic environmentally, among all the others. It contains high pollution indicators such as oil and grease; it also impacts on the soil and water properties. Discharging POME into the soil tampers withits pH, which is one of the major factors affecting nutrient availability to plants. POME also changes the soil appearance and properties in terms of vegetation, odour, colour and constitution, making the soil to lose its vegetative cover. This leads to water logging of the pores and subsequent death of vegetation, leaving the environment bare. During the rainy season, POME serves a breeding habitat for mosquitoes and produces offensive odours. When discharged into rivers, streams or surrounding lakes, the water turns brown, smelly and slimy, aquatic organisms get killed, and local people are denied the availability of water for domestic uses and fishing. The discharge of POME on the soil and surrounding lands can also contaminate the aquatic ecosystem during runoff, leading to acidification and eutrophication. The paper concludes by suggesting options for effective management such as the use of POME for microalgae cultivation, the use of pre-treated POME as fertilizer; focusing on phytoremediation, bioremediation and mycoremediation of POME-contaminated soil and water as options for the rehabilitation of POME-contaminated soils and water bodies
Evaluation of organic and inorganic pollution indicators in a homeland river
Get PDFA research article with figures and tablesThe objective of this study was to develop a biannual database for selected organic and inorganic river pollution indicators. The DO, BOD and COD levels alongside TSS and TDS concentrations were determined using standard protocols. The compiled database consisted of 5 aforementionedduring the biannual study generating over 60 data per specific parameter with 60 data per variable, per season per annum. April/May recorded highest values of TSS at "UT" sampling pointvalues of TSS at 60.38 mg/L exceeding the APHA, EU, EPA and FME discharge limits, except WHO standards. Highest TDS (68.20 mg/L) was in 2014 (Oct/NOV) at "DS" sampling point which exceeded FME and EPA pebelow WHO, EU and APHA standards. Observation shows that 2015 was an active DO year much more than 2014 and DO decreased significantly as water flows downstream. Moreover, the highest COD concentration was 290 mg/L at "NB" sampling point during Oct/Nov that was high but below APHA standard. However, the BOD levels between the seasons showed no seasonal variation within each year, which might be due to active and regular discharge of organic pollutants from abattoir source throughout the biannual study. ANOVA analyses showed that BOD and TSS data were statistically more accurate than other parameters. In conclusion, the river is unsafe, unclean and unacceptable for public consumption, recreation, sensitive fish habitation, requires pollution and preventive measures