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Compressive and Flexural Behaviour of Unstressed Concrete Substructure in Cassava Effluent Contaminated Soils [PDF]
Adekunle P. Adewuyi, Oluwole A. Olaniyi, Oladipupo S. Olafusi, Ademola S. Fawumi
Open Journal of Civil Engineering (OJCE) , 2015, DOI: 10.4236/ojce.2015.52024

Abstract: Concrete research is gradually shifting from the conventional strength-based approach to durability-centred in the past decade. Durability is the measure of the robustness of constructed facilities against deterioration tendencies. The rate of deterioration is affected by the loading condition, and more importantly the physical and chemical nature of the host environments. This paper reports the experimental investigation of unstressed concrete substructure in the natural (uncontaminated) and cassava’s hydrocyanide effluent-polluted soils on the compressive and flexural strengths of buried concrete specimens for a maximum of 84 days. The compressive strengths of the cubes were tested every 7 days until the 84th day, while the beams were only subjected to third-point loading flexural tests at age 84 days. The compressive strength of concrete specimens in the two soil environments increased, though the trend was lower in the polluted soil. The strength reduced by 2.50% to 9.47% between the 7th and 28th days, but steadily between the 28th and 84th days with strength loss of 9.95% (COV = 2.64%). The load-deflection curves were quadratic for the beams in the two geo-environments. The beams in cyanide-polluted soil lost 34.5% of its flexural stiffness, while its loss of load-carrying capacities at the first crack and ultimate failure was 15.8% and 20% respectively. Higher degree of deterioration is certain for loaded concrete substructures in similar conditions. Hence, prior knowledge of soil chemistry is crucial to determining suitable concrete grade and nominal cover for durable substructural elements.

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Evaluation of Fresh and Hardened Properties of Self-Compacting Concrete [PDF]
Oladipupo S. Olafusi, Adekunle P. Adewuyi, Abiodun I. Otunla, Adewale O. Babalola
Open Journal of Civil Engineering (OJCE) , 2015, DOI: 10.4236/ojce.2015.51001

Abstract: This paper compared the rheological properties and compressive strengths of self-compacting concrete (SCC) and conventional cement concrete. The flowability and segregation resistance of freshly mixed concrete specimens were examined by the V-funnel apparatus, while the characteristics of passing ability were investigated with the L-box apparatus. Cylindrical concrete specimens of 100 mm diameter × 200 mm length were investigated for compressive strength. The rheological properties of SCC are incomparable with those of the conventional concrete due to their diverse testing methods and characteristics of individual flow. The compressive strength results of hardened concrete showed that SCC gained strength slowly compared to the conventional cement concrete due to the presence of admixtures and its 28 days strength was lower than conventional cement concrete, but SCC eventually had potentials of higher strength beyond 90 days. Finally, the effect of water-cement ratio on the plastic properties of self-compacting concrete was quite negligible compared to conventional concrete.

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Comparative Studies of Steel, Bamboo and Rattan as Reinforcing Bars in Concrete: Tensile and Flexural Characteristics [PDF]
Adekunle P. Adewuyi, Adegboyega A. Otukoya, Oluwole A. Olaniyi, Oladipupo S. Olafusi
Open Journal of Civil Engineering (OJCE) , 2015, DOI: 10.4236/ojce.2015.52023

Abstract: This study comparatively evaluated the flexural performance and deformation characteristics of concrete elements reinforced with bamboo (Bambusa vulgaris), rattan (Calamuc deerratus) and the twisted steel rebars. The yield strength (YS), ultimate tensile strength (UTS) and the elongation of 50 specimens of the three materials were determined using a universal testing machine. Three beams of concrete strength 20 N/mm² at age 28 days were separately reinforced with bamboo, rattan and steel bars of same percentage, while the stirrups were essentially mild steel bars. The beams were subjected to centre-point flexural loading according to BS 1881 to evaluate the flexural behaviour. The YS of bamboo and rattan bars were 13% and 45% of that of steel respectively, while their UTS were 16% and 62% of that of steel in the same order. The elongation of bamboo, rattan and steel were 7.42%, 10% and 14.7% respectively. The natural rebars were less than the 12% minimum requirement of BS 4449. The load-deflection plots of bamboo and steel RC beams were quadratic, while rattan RC beams had curvilinear trend. The stiffness of bamboo RC beams (BB) and rattan RC beams (RB) were 32% and 13.5% of the stiffness of steel RC beams (SB). The post-first crack residual flexural strength was 41% for BB and SB, while RB was 25%. Moreover, the moment capacities of BB and RB corresponded to 51% and 21% respectively of the capacity of steel RC beams. The remarkable gap between the flexural capacities of the natural rebars and that of steel can be traced not only to the tensile strength but also the weak bonding at the bar-concrete interface. It can be concluded that the bamboo bars are suitable rebars for non-load bearing and lightweight RC flexural structures, while more pre-strengthening treatment is required more importantly for rattan for improved interfacial bonding and load-carrying capacity.

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Analysis of Poverty Profiles and Socioeconomic Determinants of Welfare among Urban Households of Ekiti State, Nigeria
D. Akerele and S.A. Adewuyi
Current Research Journal of Social Science , 2011,

Abstract: The study focused on assessment of household poverty and welfare among households in Ekiti State, Nigeria. Using a multistage sampling approach, a total of 80 households were selected and interviewed with the aid of well structured questionnaire. Data collected were subjected to analyses such as descriptive statistics, poverty index and multiple regression analysis. The result revealed the 38.30 percent of the households covered by the study were poor and would have to mobilize financial resources up to 41.80% of 1 US Dollar (N130) per day (for each household member) to be able to escape poverty. Female headed households in the study area appear to be more vulnerable to income poverty with poverty incidence, depth and severity of values 0.221 and 0.239, 0.402 and 0.191, respectively. Highest levels of poverty were found among household with 7-9 dependants with values 1.00, 0.715 and 0.511 for the incidence, depth and severity of poverty respectively. Educational levels of household head and spouse, gender of household head and dependency ratio are factors that exact significance influence on household welfare. In order to reduce poverty and promote peoples’ welfare, policies that would promote employment opportunities; educational status of household head, spouse and household members as well as efforts to enhance women access to more productive resources and investment in infrastructural development are recommended.

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High Performance Liquid Chromatographic Identification and Estimation of Phthalates in Sewer Waste and a Receiving River in Ibadan City, Southwestern Nigeria [PDF]
Gregory O. Adewuyi
Journal of Water Resource and Protection (JWARP) , 2012, DOI: 10.4236/jwarp.2012.410099

Abstract: Medical wastes have been implicated in river pollution in developing countries and most often people depend on water from such rivers for sources of livelihood. Phthalates (endocrine disruptors) are major components in medical wastes and are commonly found contaminants in aquatic environment. Most sewage treatment facilities handling medical waste are inefficient due to overuse and poor maintenance and discharge directly into rivers. This study aimed to investigate the identity and estimates the concentration of phthalates in supposed treated medical wastes from a hospital sewer and water from a receiving river. Samples were randomly collected before and after treatment by the sewer plants, while samples were randomly collected along the course of the river starting from point of discharge. Control samples were taken from upstream about 500 m along the river course. The samples were extracted by liquid-liquid chroma- tographic process using dichloromethane, after which they were cleaned up in a column of silica gel using hexane as the mobile solvent. The cleaned extracts were analyzed by HPLC. The concentrations (μg/L) of dimethyl-, diethyl-, diphenyl-, dibutyl- and di-(2-ethyl)hexyl phthalates ranged from 62.81 ± 18.53; 4.74 ± 3.57; 2.05 ± 1.80; 11.40 ± 5.58 to 141.92 ± 35.8 respectively in the sewer waste. The receiving river had a concentration (μg/L) of 9.17 ± 14.02; 0.18 ± 0.31; 0.48 ± 0.84; 2.84 ± 1.21; 61.72 ± 38.35 respectively for dimethyl-, diethyl-, diphenyl-, dibutyl- and di-(2-ethyl) hexyl phthalates. These concentrations were higher than control and far exceeded the USEPA limits of 3 μg/l recom- mended for phthalates in water. Contaminants of aquatic environment by untreated wastes from hospitals has serious implications on public health and environment as human risks for phthalate esters downstream are high and this calls for urgent need to develop strategy to build incentives for compliance in treatment and discharge of wastes into river waters.

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Assessment of Groundwater Quality and Saline Intrusions in Coastal Aquifers of Lagos Metropolis, Nigeria [PDF]
Adewuyi Gregory Olufemi
Journal of Water Resource and Protection (JWARP) , 2010, DOI: 10.4236/jwarp.2010.210100

Abstract: As a result of immense industrialisation and high population growth, groundwater is heavily relied on in Lagos metropolis to serve as an alternative source of water where surface water is seriously polluted. The continued reliance on ground water has resulted in its decline in quantity and quality. In this study, the coastal aquifers of Lagos metropolis were selected for an assessment of its groundwater quality and impact of saline intrusion. Water samples collected along the coastal region were subjected to various physicochemical analyses. Results obtained were compared with permissible values for drinking water stated by Federal Environmental Protection Agency (FEPA) and World Health Organization (WHO). The results revealed that all the water samples were significantly hard (range 522.14 – 1233.34mg/L). The salinity was delineated by conductivity measurements. Three samples had specific conductance above the stated limits for fresh water. The samples however met the stipulated limits for drinking water for the other tested parameters.

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Modelling Stock Prices with Exponential Weighted Moving Average (EWMA) [PDF]
Adejumo Wahab Adewuyi
Journal of Mathematical Finance (JMF) , 2016, DOI: 10.4236/jmf.2016.61011

Abstract:

Volatility is an important parameter for financial risk management and it is applied in many issues such as option pricing, portfolio optimization, VaR methodology and hedging; thus the forecasting of volatility or variance can be regarded as a problem of financial modelling. The objective of this paper is to forecast FTSE 100 Stock Prices of top 100 companies listed on London Stock Exchange by using the Exponential Weighted Moving Average (EWMA) Model. The data for this model are directly obtained from the UK FTSE 100 Index. In this research paper, we have examined the daily returns of FTSE 100 Stock Prices of top 100 companies listed on London Stock Exchange from the thirtieth day of June 2009 to the first day of December 2014 and equally forecasted the daily returns from the first day of December 2014 to the fifth day of February 2015 with the Exponential Weighted Moving Average (EWMA) Model. We found that there is a very high possibility that the stock prices will start to fall as from 5th February 2015 downwards.

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Adsorption kinetics of cadmium and lead by chitosan
JT Bamgbose, S Adewuyi, O Bamgbose, AA Adetoye
African Journal of Biotechnology , 2010,

Abstract: An evaluation of the kinetics and capacity of chitosan to trap lead and cadmium ions in aqueous solution was carried out at 25oC using concentration and contact time as parameters. The experiments were done as batch process. Our results show that the adsorption process is concentration-driven with high capacity of chitosan for the adsorption of these metal ions. The Infra red spectroscopic study on the chitosan and the metal-chitosan complexes reveal a metal coordination based on the observed characteristic band changes. At initial lead concentrations of 1000, 500, 400, 250 and 100 mg/L, the adsorbed lead ion concentrations are 557, 265, 218, 132 and 65 mg/L, respectively. However, for the cadmium, the adsorbed concentrations are 263, 165, 152, 78 and 45 mg/L, respectively at the same initial concentrations. The lead and cadmium adsorption kinetic behavior could not be described using the Langmuir isotherm over the whole concentration range but Freundlich isotherm conforms to the experimental data.

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Physico-Chemical Composition of Leaves, Meals and Oils of Fluted Pumpkin (Telfairia occidentalis) and Melon (Citrillus vulgaris)
A.A. Yusuf,S. Adewuyi,A.A. Lasisi
Agricultural Journal , 2013,

Abstract: Proximate composition of leaves, meals and oils of fluted pumpkin and melon were determined by AOAC methods of analysis (1984). Both meals were found to be richer in protein, fat, carbohydrate and mineral elements than leaves. Melon meal was however, higher in protein and fat; but lower in moisture, carbohydrate, fibre and ash contents than fluted pumpkin meal. Both leaves are found to be good source of vitamin C (100 105mg/100g).The quality of both oils were almost the same except in free fatty acid, para-anisidin and acid values. Mineral elements composition were determined by Atomic Absorption Spectrophotometer (AAS), except Na, and K (Flame photometer was used). Both leaves and meals have very low level of trace metals.

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