Mechanical and Structural Responses of Low Carbon Steel to Cold Rolling and Stress Relief Anneal Treatments

This study investigated the effect of deformation by cold rolling and stress relief anneal on the mechanical and structural properties of low carbon steel. The as-received steel samples were cold rolled at 20% – 40 % degrees of deformation using Buhler rolling machine in Metallurgical and Materials engineering department University of Lagos, Nigeria. Additionally, some of the cold rolled samples were annealed at a temperature of 650° C and soaked for 1 hour in a muffle furnace. The results revealed that the ultimate tensile strength (UTS), percent elongation, hardness and impact strength of the cold rolled low carbon steel improved significantly after stress relief anneal due to the elimination of induced strain hardening caused by cold rolling. The micrographs show that cold rolled + stress relief anneal caused significant recrystallization of ferrite-austenite phase to refine martensite with reduction of dislocations. Therefore, the low carbon steel can be used effectively for structural purposes in machines and equipment

Multiple pituitary hormone deficiency caused by Pit-I mutation and the challenges of management in a developing country

Background: In most developing countries, childhood endocrine disorders are not as common as infections but they do occur. Multiple pituitary hormone deficiency (MPHD) is a known cause of familial short stature. This is very rarely diagnosed in Nigerian children. We describe the challenges of diagnosis and management of childhood endocrine conditions in a developing economy using a ten year old Nigerian girl with MPHD as an illustration.Methods: Patient had auxological data suggestive of short stature. In order to make a definitive diagnosis, pituitary function tests were carried out in the United Kingdom.Results: Biochemical tests revealed growth hormone (GH) deficiency, Thyroid Stimulating Hormone (TSH) deficiency, decreased prolactin (PRL) level, normal cortisol and gonadotrophins. Her DNA analysis identified PIT-1 mutation in exon-6. She was placed on recombinant GH and thyroxine with evidence of catch up in height.Conclusions: There were challenges to management such as, inadequate facility for diagnosis, huge cost of treatment and little awareness about childhood endocrine conditions amongst health workers in a developing economy.Keywords: Multiple pituitary hormone deficiency (MPHD), PIT-1 mutation, short stature, management, developing country

Effect of PH on Geotechnical Properties of Laterite Soil Used in Highway Pavement Construction

Laterite is one of the major materials used in highway pavement construction in Nigeria. Its properties are affected by some environmental factors which may make it unsuitable for highway pavement construction. This research was aimed of investigating the effect of pH on geotechnical properties of Laterite soil used in highway construction. Laterite soil sample was collected from a burrow pit at LAUTECH and it was sun dried for about 24 hours and then soaked in different pH solutions (pH =3.0, pH=5.0, pH = 7.0 and pH= 9.0) using diluted tetraoxosulphate (vi) acid (H2SO4) and ammonia. The container was perforated at the bottom in order simulate the actual field condition. The soil samples were taken from soaked sample at 14, 28, 42, 56, 70 and 84 days for sun drying and subsequent laboratory tests. The original and treated samples were subjected to the following laboratory tests: Sieve analysis, Liquid and Plastic limits, Plasticity index, British standard compaction and California bearing ratio. The results showed that the pH of the solution has strong influence on the geotechnical characteristics of the Laterite soil when compared with the original soil sample. This influence caused reduction on the strength properties of the soil and thereby rending it unsuitable for highway construction. Keywords: Laterite, pH, consistency limits, California bearing ratio

Perception of the Use of Glass in Housing: A Case Study of Ado-Ekiti, Nigeria

The development and use of glass in recent times, particularly in the architectural sector, is a growing phenomenon across developed and under-developed economies. Public acceptability and adoption of any developed materials in Nigeria is one issue that is shrouded in uncertainty. This paper investigated the level of perception of the use of glass in housing among Ekiti people using Ado-Ekiti as a case study. It provided the background profile of glass in terms of the production, properties and peculiar uses as a housing material. It employed structured questionnaires randomly administered to residents of five selected districts of Ado-Ekiti to elicit relevant information. The information provided by respondents of different socio-economic background was subjected to factor analysis using statistical package for social sciences (SPSS). The results reflected different levels of perception in the use of glass as a building construction, furniture and kitchen utensil material in housing and the built environment in general. Key words: Perception, glass, housing materials, furniture, kitchen utensil

Prediction of Density and Viscosity of Biodiesel Fuel from Fatty Acid Methyl Ester (FAME) Composition

Viscosity and density are important properties that qualify biodiesel fuel to serve as an alternative fuel because all other properties directly or indirectly depend on them. The processes involved in determining the viscosity and density of biodiesel are relatively simple and costly and there are discrepancies in the results obtained due to the differences in the oil composition of the feed-stocks used as against the reported cause of experimental errors. This work aimed at theoretically determining and developing relationship between the density and viscosity of different feed-stocks and the fatty acid methyl ester composition at different temperatures.In the study, density and viscosity data of biodiesel fuels and the composition of FAME were collected from literatures.  A linear regression analysis was carried out for density and viscosity on the average values of viscosity and density data obtained at different temperatures range (10°C-40°C) of FAME composition. Equations relating density and viscosity with the percentage composition by weight of FAME of biodiesel fuel were developed. Predicted mean values for kinematic viscosity and density were respectively between 4.31 - 5.64 mm2/s and 861.67 – 885.66 kg/m3. The developed equations were able to predict with up to 97.1% accuracy for viscosity and 98.5% accuracy for density. The developed equations could effectively predict the quality of biodiesel (viscosity and density) from various feedstocks based on FAME compositions

Data on CaO and eggshell catalysts used for biodiesel production

This researchinvestigatedtheproductionofbiodieselfromsoy- bean oil(transesterification process)usingpurecalciumoxideand calcium oxideobtainedfromeggshellasheterogeneouscatalysts. Uncalcinedeggshellandcalcinedeggshellcatalystsproducedwere analysedusingXRFandXRDspectrometers.Theprocessingpara- meters consideredduringthetransesterification ofthesoybean weremethanol/oilmoleratio,catalystconcentrationandreaction time andtheireffectsonbiodieselyieldwereevaluated.Reaction temperatureof60 °C andstirringrateof450rpm(revolutionper minute) werekeptconstant.Asaresultofcalcination,XRFanalysis revealedanincreaseinCaOpercentagecompositionofeggshell catalystfrom96%to97%.Also,thebiodieselyieldsobtained revealedsimilarperformancepatternsforboththecalcinedegg- shell catalystandthepureCaOcatalys

Oxidation Stability of Fatty Acid Methyl Ester under Three Different Conditions

Maintaining fuel stability is one important criterion in sustaining the quality of fuels. This research investigated the production of biodiesel from waste groundnut oil and the oxidation stability of the biodiesel samples stored under three conditions (a vacuum, a fridge and an exposure to atmosphere) by considering their saponification values, percentage of free fatty acid, peroxide values, iodine values and viscosity. Maximum biodiesel yield was obtained at 9 methanol/oil mole ratio, 1.0w/w%Oil KOH catalyst concentration, reaction time of 60 minutes and reaction temperature of 60 0C. The results showed that biodiesel oxidation stability is adversely affected by increase in saponification value, percentage of free fatty acid, peroxide value; and decrease in iodine value and viscosity. Also, the results of these physico-chemical properties shows that vacuum is the most favourable storage condition, compared to freezing and atmospheric condition

Effects of Sodium Hydroxide Concentration on Zeolite Y Synthesized from Elefun Kaolinite Clay in Nigeria

Zeolite Y was synthesized hydrothermally from Elefun kaolinite clay. The raw kaolinite was calcined at 8500C to obtain more reactive clay (metakaolin). The metakaolin was dealuminated using non-heating methods to obtain the optimum dealumination route desired silica to alumina ratio between 3 and 7. The non-heating method proved successful in producing a desired ratio of 4 which was used in producing the aluminosilicate gel. The aluminosilicate gel was aged for 7 days at 950C for 36 hours with varying Na2O/SiO2 ratios of 0.60, 0.65, 0.70, 0.75 and 0.80 to produce zeolite Y. The synthesized zeolites were characterized by X-ray diffraction (XRD) analysis. The effect of NaOH concentration was studied using the XRD patterns of synthesized zeolite Y samples with reference to a standard zeolite Y. The results indicated zeolite Y of low crystallinity accompanied with other impure phases. Furthermore, the concentration of NaOH improved the intensity of the zeolite Y crystal peaks. The Na2O/SiO2 ratio that gave the highest crystallinity optimal ratio was found to be 0.75 with NaOH concentration of 3.8

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