A Methodology to Predict the Remaining Service Life of CSCPs

Despite the fact that corrugated steel culvert pipe (CSCP) is widely used for stream crossings and drainage in many transportation systems in the US, historically, very little has been done regarding its condition assessment and planned maintenance. This research provides a methodology for developing a comprehensive plan for inspection, cleaning, condition assessment and prediction of remaining service of CSCP. Inspection frequency guidelines were developed based upon culvert size, age, importance and environmental factors, e.g., corrosion and erosion, bed load and pH. The CSCPs are classified into three levels according to increasing need for inspection, e.g., annual inspections are recommended for Level III. A four Condition State assessment system was developed based upon the CalTrans system, which includes quantifiable section losses, specific surface features, and a prescribed response associated with each condition state. A Markov deterioration model was used to predict the future Condition States and the probability of failure of new CSCP over a 30-year life for both urban and rural settings. The transition probabilities were based upon inspection data and corrosion case studies. The probability of failure ranged from 25 to 65 percent for the rural and urban areas respectively. Improvements to the model that will take into account the effects of maintenance and rehabilitation will be addressed in the next phase of the research project

A Methodology to Predict the Remaining Service Life of CSCPs

Despite the fact that corrugated steel culvert pipe (CSCP) is widely used for stream crossings and drainage in many transportation systems in the US, historically, very little has been done regarding its condition assessment and planned maintenance. This research provides a methodology for developing a comprehensive plan for inspection, cleaning, condition assessment and prediction of remaining service of CSCP. Inspection frequency guidelines were developed based upon culvert size, age, importance and environmental factors, e.g., corrosion and erosion, bed load and pH. The CSCPs are classified into three levels according to increasing need for inspection, e.g., annual inspections are recommended for Level III. A four Condition State assessment system was developed based upon the CalTrans system, which includes quantifiable section losses, specific surface features, and a prescribed response associated with each condition state. A Markov deterioration model was used to predict the future Condition States and the probability of failure of new CSCP over a 30-year life for both urban and rural settings. The transition probabilities were based upon inspection data and corrosion case studies. The probability of failure ranged from 25 to 65 percent for the rural and urban areas respectively. Improvements to the model that will take into account the effects of maintenance and rehabilitation will be addressed in the next phase of the research project

ANALYTICAL INVESTIGATION OF THE EXTRACT OF LEMON GRASS LEAVES IN REPELLING MOSQUITO

ABSTRACT: The main objective of the work was to extract the active ingredient in Cymbopogon citratus leave and to formulate a mosquito repellent cream naturally obtained from medicinal plants instead of commonly available synthetic repellents and insecticides such as N-Diethyl-3methylbenzamide (DEET), which are carcinogenic and non eco-friendly. The formulation of cream have smooth texture with a pH 7.30 which is non-irritant and suitable for the skin. The efficacy of the extract of Lemon grass (Cymbopogon citratus) was investigated on mosquito in this research using different concentrations of the oil extract. The sample (cream) with the highest concentration of the active ingredient extracted was found to be most effective in repelling mosquitoes. Ethanol and Hexane were used to extract the essential oil and Gas chromatography-mass spectrophotometer (GC-MS) was used to analyse the constituents in the extracted active oil. The most abundant constituents observed in the hexane extract are cyclotetracosane (4.05%) and naphthalene (5.03%). Hexane proved to be a better solvent by giving a percentage yield of 7.8% of essential oil while ethanol a percentage of 2.9%

The use of Waste Duck Eggshells for Sustainable Energy Production

In this study, waste duck eggshells were processed into high grade CaOheterogenous catalyst for the esterification-transesterification of palm kernel oil (PKO) to obtain biodiesel. The production processes involved are calcination of duck eggshells into CaO, XRD and XRF analysis of CaO produced, PKO fatty acid components determination, transesterification of the esterified PKO and the formulation of a suitable model. High biodiesel yield of 84% was obtained at catalyst concentration of 9 wt./wt. %, reaction time of 2 hours and methanol/oil mole ratio of 13, using CaO catalyst (derived from duck eggshell). The good quality of biodiesel produced was ascertained by its properties that fall within ASTM specifications (kinematic viscosity of 4.1 mm2/s, flash point of 1950C, density of 869kg/m3, water content of 0.045 v/v %)

Production of Biodiesel from Soybean Oil Using Calcium Oxide and Cow Bone as Catalysts

Biodiesel was produced from the transesterification of soybean oil using calcium oxide and cow bone (an animal waste bone that contains hydroxyapatite, a calcium phosphate mineral) as heterogeneous catalysts. The soybean oil used was characterized using gas chromatography mass spectrometer (GCMS) and the cow bone catalyst produced was characterized using X-ray diffractometer (XRD) and X-ray fluorescence (XRF) spectrometer. The effects of the variation of methanol/oil mole ratio (9–15), catalyst concentration (10–20 wt/wt%) and reaction temperature (55–65 °C) on biodiesel yield during the transesterification of soybean oil with methanol was investigated. Reaction time of 3 hours and stirring rate of 500 rpm were kept constant. It was observed that the calcination of cow bone catalyst (at 800 °C) enhanced its conversion to apatite [Ca5(PO4)3OH] and increased the yield of biodiesel obtained. Biodiesel yield results revealed an optimum condition of methanol/oil mole ratio of 9, catalyst concentration of 15 wt/wt% and reaction temperature of 55 °C. Also, the results obtained showed that the performance trends of the two catalysts used were similar. And the close values of highest biodiesel yields obtained when the two heterogenous catalysts were used separately (yields of 94.8 and 92.2% using calcium oxide and calcined cow bone catalysts respectively) implies that the use of low-cost and readily available calcined cow bone catalyst is a promising alternative to CaO catalyst

Evaluation of Antioxidant Activity of Tetracarpidium conophorum (Müll. Arg) Hutch & Dalziel Leaves

This study evaluated the antioxidant activity as well as bioflavonoid content of the methanol and ethanol-water extracts of the fresh and dried leaves of Tetracarpidium conophorum. Antioxidant activity was determined by spectrophotometric methods using DPPH free radical, nitric oxide radical inhibition and ferric reducing antioxidant power assays. In addition, total phenolics, flavonoids and proanthocyanidin content were also determined. The ethanol: water extract of the dried leaves had the highest antioxidant activity with a 50% inhibition of DPPH at a concentration of 0.017 mg/mL compared to the standards, Vitamin C and Vitamin E with inhibition of 0.019 and 0.011 mg/mL, respectively. This extract also showed nitric oxide radical inhibition activity comparable to that of rutin, 54.45% and 55.03% for extract and rutin, respectively, at 0.1 mg/mL. Ferric reducing power was also comparable to that of ascorbic acid (281 and 287 μM Fe (11)/g, resp.) at a concentration of 1 mg/mL. The methanol extract of both the dried and the fresh leaves had higher phenolic, flavonoids and proanthocyanidin content than the ethanol : water extract. The study reveals that T. conophorum can be an interesting source of antioxidants with their potential use in different fields namely food, cosmetics and pharmaceuticals

Adult and paediatric mortality patterns in a referral hospital in Liberia 1 year after the end of the war

The aim of this study was to describe and analyse hospital mortality patterns after the Liberian war. Data were collected retrospectively from January to July 2005 in a referral hospital in Monrovia, Liberia. The overall fatality rate was 17.2% (438/2543) of medical admissions. One-third of deaths occurred in the first 24h. The adult fatality rate was 23.3% (241/1034). Non-infectious diseases accounted for 56% of the adult deaths. The main causes of death were meningitis (16%), stroke (14%) and heart failure (10%). Associated fatality rates were 48%, 54% and 31% respectively. The paediatric fatality rate was 13.1% (197/1509). Infectious diseases caused 66% of paediatric deaths. In infants <1 month old, the fatality rate was 18% and main causes of death were neonatal sepsis (47%), respiratory distress (24%) and prematurity (18%). The main causes of death in infants > or =1 month old were respiratory infections (27%), malaria (23%) and severe malnutrition (16%). Associated fatality rates were 12%, 10% and 19%. Fatality rates were similar to those found in other sub-Saharan countries without a previous conflict. Early deaths could decrease through recognition and early referral of severe cases from health centres to the hospital and through assessment and priority treatment of these patients at arrival

Neuropharmacological profile and chemical analysis of fresh rhizome essential oil of Curcuma longa (turmeric) cultivated in Southwest Nigeria

Background: Curcuma longa (turmeric) is commonly used as spice and also used to treat fever, cough and febrile convulsions in Nigeria. This study determined the chemical composition of the essential oil of C. longa and evaluated its neuropharmacological activity in mice. Methods: Essential oil of C. longa (EOCL) fresh rhizome was obtained by hydrodistillation and its chemical composition determined by GCâMS. Acute toxicity (LD50) profile of the essential oil was determined orally (p.o.) and intraperitoneally (i.p.); and the EOCL (50â200 mg/kg, i.p.) was evaluated for its behavioural, anxiolytic, sedative and anticonvulsant activities using appropriate models in Albino mice (Vom Strain, Jos, Nigeria). Results: Analysis of the oil showed the presence of 23 compounds with turmerone (35.9%) being the major component. The LD50 values obtained for the mice were 2154 mg/kg, p.o., and 693 mg/kg, i.p.The EOCL (50â200 mg/kg, i.p.) caused significant (p < 0.01) inhibition of rearing {F(4,20) = 9} and locomotor {F(3,16) = 42} activity; decreased head dips in hole board {F (4,20) = 4}; increased the time spent in the open arms of the elevated pus maze {F (4,20) = 9}; prolonged total sleeping time {F (4,20) = 21} induced by ketamine injection, and protected mice against pentylenetetrazol-induced convulsions. Conclusion: The major component of the essential oil of this C. longa species was turmerone; the oil was slightly toxic orally but moderately toxic intraperitoneally in mice; exhibited significant anxiolytic, sedative and anticonvulsant activities in mice. Keywords: Turmeric, Essential oil, Turmerone, Behavior, Acute toxicity, Sedative, Anticonvulsan