Numerical investigation into the effect of various surcharge loadings on propped wall excavations and embankments

Several guidance and formulation have been developed in the literature to account for the analysis of external surcharges adjacent to a propped excavation but less attention has been paid to the presence of sloping ground or embankments. However, CIRIA C760 states that the actual ground profile should be modelled and analysed as a series of surcharge loading over the extent of the active side of the wall. In this research, two braced excavation models were analysed of which one was the actual ground profile and the second with a series of surcharge loading representing the embankment adjacent to the excavation. The accuracy, efficiency, and conservation of the proposed approaches were examined on a propped cantilever wall excavation using a finite element geotechnical analysis software PLAXIS 2D. The models were analysed and examined in terms of the bending moment and deflection of the diaphragm wall and the prop load, the model with the actual ground profile was also investigated for any thrust load on the support system should the embankment or sloping ground fail in shear. The results were presented, and comparisons were made. Merits and advantages of the proposed numerical approach were discussed

Migraine with Prolonged Aura: Correlation of Clinical and EEG Features

Migraine with prolonged aura has rarely been examined with regard to the sequence of the neurological symptoms and the associated EEG changes. This report describes five patients who underwent clinical assessment and EEG recordings during attacks of migraine with prolonged aura. CT scan of the brain was obtained in four of them. Follow-up EEG was also obtained. The aura symptoms either preceded the headache or were coincident with it. The aura symptoms evolved in a manner consistent with posterior-to-anterior dysfunction of the cerebral cortex. The EEG abnormalities were non-epileptiform and consisted of focal delta slow waves or theta slow waves. The EEG abnormalities showed good correlation with the patients' aura symptoms and resolved when the patients became symptom free. The posterior-to-anterior sequence of the aura symptoms is in accord with the findings during cerebral blood flow studies in patients having migraine with aura. Also the symptoms and EEG changes in our patients indicate dysfunction of the cerebral cortex, consistent with the notion that spreading cortical depression may be the underlying pathophysiological event in migraine with aura

Exploring the roles of people, governance and technology in organizational readiness for emerging technologies

The rapid development and release of emerging technologies have made their adoption challenging. Most often there are failing issues in organizational adoption of emerging technologies. It is yet unclear which component(s) of organization play the prominent role(s) in organizational readiness to adopt emerging technologies. Using a mixed method, this study conducted an online survey of 83 South African organizations for server virtualization adoption. Server virtualization is an emerging technology being widely adopted in most organizations in developed countries. IT executives rated server virtualization as the second-most important technology to help achieve cost reductions and optimize productivity in recent surveys. Very little is known about server virtualization adoption in organizations in developing countries. It was found that people and technology play prominent roles in South African organizational readiness to adopt server virtualization. Server virtualization has certain inhibitors such as lack of IT skill, and software and license costs that the IT industry and adopting organizations should consider

Pi-Conjugated Phosphole Derivatives: Promising Building Blocks for ?-Conjugated Organic Materials

Pi-Conjugated organophosphorus derivatives have recently emerged as valuable building blocks for the tailoring of functional molecular materials. In order to guide the synthesis of novels materials with low band gaps, theoretical study on the geometries and electronic properties of new conjugated compounds based on low coordinate heterophosphole compounds were carried out. The theoretical ground-state geometries and the electronic structures of the studied molecules were obtained using the density functional theory (DFT) method at B3LYP level with 6-31G(d) basis set. The effects of the phosphorus and different heteroatom elements on the geometries and electronic properties of these materials were discussed. The results from this study show that conjugated molecules containing phosphorus atom gives better electronic properties compared to their organic counterparts that had been used in optoelectronic devices. Hence these compounds could be a good promising building blocks candidate for opto-electronic applications. Keywords: Conjugated Compounds, Electronic Properties, Density Functional Theory, Opto-Electronic Devic

MOTIVATION AND ETHICS: CRITICAL FACTORS FOR SUSTAINABLE PUBLIC SERVICE DELIVERY IN NIGERIA

The primary function of any government is to ensure an equitable distribution of public goods and services to its citizens. Despite the material and human resource in Nigeria, Nigerians have been short-changed by the quality of public service delivery in the country. Against this backdrop, this paper: examined the issues affecting public service delivery and demonstrated how motivation can enhance ethical behaviours among public servants. Corruption Perception Index (CPI) from year 2000 to 2016 was used to argue the position of the paper. The study discovered, among other things that certain Human Resource (HR), political and institutional factors have led to the erosion of moral conduct by public servants. While measures such as reforms and campaigns have been taken to curb political and institutional issues, limited remedial actions have been proffered to tackle that of HR. These have negatively affected public service delivery in Nigeria. Therefore, apart from putting some ethical principles in place, there is need to motivate public servants to get at their best. In addition to this, good behaviour is to be rewarded and bad behaviour is to be punished across all public services in the country, by a truly independent and incorruptible statutory body. By doing this, sanity and equitable service delivery will be achieved.     &nbsp

Cereals and grain legumes supply chain: implications for food and feed availability in Nigeria

Cereals and grain legume are of benefits for human consumption and the feed industry. Grain merchants and market speculators are involved in their distribution across the country. Their low production outputs with imports restriction made their supply grossly inadequate to meet the demand. This paper examined selected grains output in Nigeria from 2010 to 2022, analysed grain supply chain and examined the implications of the activities of grains merchants on grains hoarding. The study used secondary data on output of maize, millet, sorghum, soybean, groundnut and cowpea. Data was presented using table and graph with the aid of Stata software. Conceptual analysis was adopted for the demonstration of grains supply flow. In 1,000 metric tonnes, output of millet reduced from 5,170 in 2010 to 2,000 in 2022. That of maize increased from 7,677 in 2010 to 12,745 in 2021; sorghum’s output reduced from 7,141 to 7,000 while that of soybean increased from 142 in 2010 to 680 in 2022. Outputs of millet and sorghum dipped between 2011 and 2013. Grain merchants and speculators hoard grains and sell at higher prices to households and feeds industry due to yearly excess demand over supply. Households buy grains and livestock products at higher prices, households in turn makes labour available to farmers at higher prices with concurrent general price increases. This affects food and feed availability. The paper recommended that Government should purchase grains directly from farmers. Industrial users should also be encouraged to be off-takers of grains through contract farmin

Isolation and characterisation of nitrilase producing Aspergillus species recovered from solid waste leachates at two dump sites in Lagos, Nigeria

Aims: Nitrile compounds are cyanogenic intermediates, products, byproducts and waste products of agriculture, chemical and pharmaceutical industries and fossil fuels degradation. The enzymatic hydrolysis of nitriles to non-toxic carboxylic acids or amides plays an increasingly important role in environment remediation. This study aimed at exploring the potential of Aspergilli in the detoxification nitrile compounds at two selected dump sites in Lagos, Nigeria. Methodology and results: Decomposing solid waste leachate samples (SWL) were randomly collected at two selected dump sites namely Olusosun (Ojota) and Isolo (Oke-Afa). Samples per site were pooled, processed by selective enrichment and screened for the presence of Aspergilli by culture technique and intergenic spacer sequencing (ITS). Biomass generation and pH changes in the culture fluids were monitored at 4-days interval by dry weight measurements. Nitrilase production was determined spectrophotometrically. Two nitrilase producing Aspergillus strains: Aspergillus fumigatus strain WO2 with accession number MF78882 and Aspergillus niger strain WO7 with accession number MH542673 were identified. Growth investigation revealed biomass generations of 17.8 g and 23.8 g dry weight per one liter media for A. fumigatus strain WO2 and A. niger strain WO7 respectively. Progressive pH monitoring showed decline from 7.2 to 4.5 and 7.2 to 6.2 was obtained for strains WO2 and WO7 respectively, during nitrilase production at different yields of 0.0150 and 0.0161 mg/mL/min respectively. Conclusion, significance and impact of study: This study supports the studied dump sites as important sources of nitrilase-producing A. fumigatus and A niger strains with potentials as cost-effective environmental bioremediation agents in Nigeria

Genotoxicity Evaluation of Landfill Solid Waste Leachates from a Waste Dumpsite in Lagos State, Nigeria using the Allium cepa Assay

The management of municipal landfill’s leachate is considered one of the most significant environmental issues. Potential mutagenic and genotoxic effects of solid waste leachates (SWL) were investigated using the Allium cepa root meristematic cells assay technique. In Allium root growth inhibition test, experimental onion bulbs were cultivated in various concentrations of the SWL and distilled water was used as a negative control. The root tips from the treated bulb were processedby orcein squash technique after 72 h. The mean lengths of root bundles were obtained andeffective concentration (EC) values calculated. Some of the physicochemical properties of the WL were also determined. The A. cepa assay was carried out at concentrations of 0.05, 0.1, 2.0, 5, 10, 20, 50 and 100% of the WL. There was a statistically different (p < 0.05), concentrationdependent inhibition of onion root growth and mitotic index, and induction of chromosomal aberrations in the onion test. The results of the physicochemical analysis revealed that the concentrations of some parameters were above the maximum permissible limit set by the world health organization (WHO) and could partly be correlated with the toxicity of wastewater. The landfill leachates pose a risk to human health and the environment in general. Hence, ecotoxicity/genotoxicity assays would be useful in leachate risk assessment when coupled with physicochemical analysis

Toxicity evaluation of waste effluent from cassava-processing factory in lagos state, nigeria using the Allium cepa assay

Mutagenic and genotoxic effects of cassava wastewater (CWW) were investigated by assay of Allium cepa root meristematic cells. The physicochemical parameters of the wastewater samples showing cyanide content were also determined. In Allium root growth inhibition test, experimental onion bulbs were cultivated in various concentrations of the CWW and distilled water was used as a negative control. After 72 h, the root tips from the treated bulb were processed for cytological studies by orcein squash technique. The mean lengths of root bundles were obtained and effective concentration (EC) values calculated. The cytotoxic effects on the onion root tips showed strong growth retardation at high concentrations of the effluent with EC value of 10%. The 50 mitotic index (MI) rapidly decreased with increasing effluent concentration compared to control. There was significant increase in frequency of chromosome aberrations (sticky chromosome, c-mitosis, vagrant chromosome, bridges fragment, binucleated cells, multipolar anaphase, attached chromosome and laggard chromosome) in root tip meristem cells of Allium cepa at all tested concentrations. Further analysis using oneway ANOVA revealed that there was a statistically significant difference (p<0.05) in concentration-dependent inhibition of onion root growth, mitotic index and induction of chromosomal aberration in the Allium cepa test. The results indicate that the effluent samples collected were highly mutagenic. The results of physicochemical analysis revealed that the concentrations of some parameters (conductivity, total suspended solid (TSS), total dissolved solid (TDS), biological oxygen demand (BOD), nitrate, cyanide, chloride and metals-magnesium, aluminum, chromium, cadmium, manganese and iron) were above the maximum permissible limit set by world health organization (WHO) and could partly be correlated with the toxicity of wastewater. The findings indicate that the substances contained in the cassava effluents may be toxic to living organisms and may pollute the environment if untreated

Antibiotics resistance of a strain of Escherichia coli isolated from bore hole in Ile Ife, Osun state, Nigeria

Abstract:Escherichia coli were isolated from water from two boreholes in Ile Ife, Osun state, Nigeria. This was an indication of faecal contamination. These strains of Escherichia coli were Gram negative short rods, Catalase positive, Methyl red positive, Voges Proskaeur negative. The strains could ferment glucose galactose, sucrose, lactose, mannitol and maltose with the production of acid and gas but could not hydrolyze starch. A particular strain was resistant to sulfamethoxazole, ampicillin, cotrimoxazole, cephaloridine, streptomycin, carbenicillin, sulfafurazole and tetracycline but sensitive to gentamicin, colistin, nalidixic acid, nitrofurantoin and colistin sulphat