Impact of substrate amendment on the polyaromatic hydrocarbon contents of a five month old waste engine oil polluted soil

The present study investigated the impact of substrate amendment on the bioremediation of waste engine oil-polluted soil. Top soil was collected randomly from a 50 × 50 m marked plot on a farmland, sun-dried and weighed. Ten kilogram’s of soil each was placed into perforated 25 L buckets. Waste engine oil (WEO) was prepared at 5 different levels of pollution: 0, 1.0, 2.5, 5.0, and 10.0% w/w, and poured into the measured soil, and thoroughly mixed. The entire set up was left under an open shade for 5 months without mechanically disturbing the soil, after which the polluted soil was amended with sawdust and left for a further 9 months. Significant reductions in polyaromatic hydrocarbon (PAH) content of soils over the experimental period were recorded. Total (100%) remediation of some PAH compounds (benzo[a]anthracene, benzo(a)pyrene, benzo[b]fluoranthene, benzo[g,h,i]perylene, benzo[k]fluoranthene, chrysene, dibenzo[a,h]anthracene, fluoranthene, fluorene, and indeno[1,2,3-c,d]pyrene) was recorded. Total PAH ranged from 1.10 to 6.35 mg/L in the substrate-amended treatment compared to a range of 25.45 to 456.99 mg/L in the unamended soil. Toxicity equivalencies (TEQ) in the unamended soils were generally higher than benchmark values, implying that the cleanup levels were not met. In the amended treatments, however, TEQs were presented for only benzo[a]pyrene (0.7284) in the control and indeno[123-c]pyrene (0.0272) in 2.5% w/w oil in soil treatment. TEQ’s of benzo[a]pyrene in the amended 5% w/w oil in soil treatment was 3.1252 mg/L, also higher than the benchmark TEQ of 1.0 mg/L.Key words: biooremediation, substrate amendment, polyaromatic hydrocarbon

Economy-wide and distributional impacts of an oil price shock on the south African economy

As crude oil prices reach new highs, there is renewed concern about how external shocks will affect growth and poverty in developing countries. This paper describes a macro-micro framework for examining the structural and distributional consequences of a significant external shock-an increase in the world price of oil-on the South African economy. The authors merge results from a highly disaggregative computable general equilibrium model and a micro-simulation analysis of earnings and occupational choice based on socio-demographic characteristics of the household. The model provides changes in employment, wages, and prices that are used in the micro-simulation. The analysis finds that a 125 percent increase in the price of crude oil and refined petroleum reduces employment and GDP by approximately 2 percent, and reduces household consumption by approximately 7 percent. The oil price shock tends to increase the disparity between rich and poor. The adverse impact of the oil price shock is felt by the poorer segment of the formal labor market in the form of declining wages and increased unemployment. Unemployment hits mostly low and medium-skilled workers in the services sector. High-skilled households, on average, gain from the oil price shock. Their income rises and their spending basket is less skewed toward food and other goods that are most affected by changes in oil prices.Economic Theory&Research,,Labor Policies,Markets and Market Access,Access to Finance

Field emission-driven microdischarges

For over half a century, it has been known that the onset of field emission can lead to anomalous breakdown for electrode gaps spaced \u3c10 μm apart. In adddition, field emission can serve as a substantial source of primary electrons in a microdischarge operating well below the breakdown threshold at atmospheric pressure. To better understand the role of field emission in a microdischarge, we have developed kinetic simulations and fluid models. Theoretical results from both our simulations and models have shown that the anomalous breakdown at the microscale is due to ion-enhanced field emission. In addition, they predict an entirely new prebreakdown regime – the field emission-driven microdischarge – in which field-emitted electrons interact with the surrounding gas to produce ions and excited metastables. Experiments conducted in our lab agree well with the predictions of our simulations and fluid model for parallel plate electrode spacings ranging from 4.8 to 14 μm

2014 Workshop on Thermionic Energy Conversion for Space and Earth

No abstract availabl

Eco-taxonomic distribution of plant species around motor mechanic workshops in Asaba and Benin City, Nigeria: Identification of oil tolerant plant species

A survey of plant species and their families present in auto mechanic workshops in Benin City and Asaba was carried out. The frequency of occurrence of plants in the sites visited was used to determineprevalence. Peperomia pellucida occurred most in all the sites visited with a 55% frequency. The high rate of occurrence of a particular plant species in the frequency table, suggests that such plants are tolerant and may be introduced as a possible phytoremediating agent

New selection rules for resonant Raman scattering on quantum wires

The bosonisation technique is used to calculate the resonant Raman spectrum of a quantum wire with two electronic sub-bands occupied. Close to resonance, the cross section at frequencies in the region of the inter sub-band transitions shows distinct peaks in parallel polarisation of the incident and scattered light that are signature of collective higher order spin density excitations. This is in striking contrast to the conventional selection rule for non-resonant Raman scattering according to which spin modes can appear only in perpendicular polarisation. We predict a new selection rule for the excitations observed near resonance, namely that, apart from charge density excitations, only spin modes with positive group velocities can appear as peaks in the spectra in parallel configuration close to resonance. The results are consistent with all of the presently available experimental data.Comment: 7 pages, 2 figure

Peripheral arterial disease in rheumatoid arthritis patients at the Kenyatta National Hospital, Kenya

Objective: To determine the magnitude of the rosclerotic arterial disease in Rheumatoid Arthritis(RA) patients at Kenyatta National Hospital.Design: hospital based cross-sectional study.Setting: Kenyatta National Hospital Rheumatology outpatient clinic.Subjects: Rheumatoid Arthritis patients.Results: We obtained ABI measurements in 90 RA patients, among them 23(25.5% 95% CI 17.2-36.1) had obstructed lower limb arteries. Among the 23, 21(91.3%) had mild PAD, two (8.7%) had moderate PAD; none had severe PAD nor incompressible vessels. The obstruction of vessels was independent of diabetes, hypertension, dyslipidemia and cigarette smoking though these factors increased the likelihood of having PAD. Risk age( ≥45 males, ≥55 females), Established RA(> 5 year duration) and severe RA were found to be significantly associated with the likelihood of having PAD. These trends remained significant after multivariable adjustment for potential confounders. twenty five (27.7%) of the study subjects exhibited symptoms of intermittent claudication, 13(52%) of them had PAD on ABI measurements, The Edinburgh claudication questionnaire was found to have 56.5% sensitivity and 82% specificity in detectionof PAD in RA patients. Conclusion: There seems to be an association between PAD in RA with chronicity and severity of the RA. This association may support the pathogenic role of accumulated systemic inflammation in atherosclerosis. Clinicians should be alert to the possibility of impared arterial function and thus subsequent cardiovascular morbidity and mortality in this group of patients

The Effects of Spent Engine Oil on Soil Properties and Growth of Maize (Zea mays L.)

The effect of spent engine oil (SEO) on soil properties and growth of maize (Zea mays L.) was investigated. Five treatments (0.0, 0.2, 0.4, 0.6 and 0.8 l/kg) of the spent oil were applied to soil in perforated poly bags with maize stands at four weeks after sowing. Soil analysis showed that SEO had no effect on both the pH and texture of the soil. Organic C, N and Mg in the contaminated soils increased compared to the control. Therewas decrease in concentration of P due to soil contamination. Heavy metals (Fe, Cu, Zn and Pb) concentrations of soil increased with increasing concentration of oil. Plant height, root number and root length of maize plants grown in the contaminated soils were adversely affected. The grain yield of the plants in the contaminated soils was significantly reduce

Health and the millennium development goals. The Nigerian perspective

No Abstrac