Aniline effect on concrete steel rebar degradation in saline and sulfate media

Electrochemical potential monitoring experiments were performed on mild steel rebars embedded in concrete admixed with aniline inhibitor and fixed amount of sodium chloride salt partially immersed in sulfuric acid and sodium chloride solution. The open circuit potential corrosion monitoring technique was employed and the potential readings were taken in accordance with ASTM C 876. Repressive attribute and consistency of the inhibitor was then estimated by the Weibull probability density distribution as an extreme value statistical modeling approach to study performance effectiveness and to predict the most efficient inhibitor concentration in each media. Aniline effect on the compressive strengths of the reinforced concrete samples was also investigated and reported. Varying concentrations of the inhibitor were used and its performance improved as concentration changed in NaCl medium, while no particular order of performance was noted in sulfuric medium. In the statistically analyzed experimental results for each of the inhibitor concentrations employed, 0.34 and 0.41 M aniline admixed samples were identified as exhibiting the best inhibiting quality in sodium chloride while 0.14 M aniline was predicted as showing the lowest probability of corrosion risk in sulfuric acid medium. The overall effective inhibitive performance in sulfuric acid was less when compared to the sodium chloride medium. Concrete sample admixed with 0.41 M aniline had the highest improvement in compressive strength in both media

Biomembrane Modelling in Planar Chromatographic Determination of Lipophilicity Using Olive and Castor Oils

BackgroundLipophilicity is a crucial physicochemical parameter that predicts in vivo pharmacokinetics and should be reliably estimated in early stage drug discovery to reduce incidence of attrition. Previous methodologies for its measurement often lead to technically incorrect decisions due to simplistic architecture and poor biomimetic attributes. Significantly, a certain seed oil, used for biomembrane modelling on planar chromatographic platform, was reported to be sufficiently biomimetic and fit for purpose.ObjectivesTo evaluate olive oil (OL) and olive-castor oil (OL-C) equi-mixture as lipids for biomembrane simulation on planar chromatographic platform.Material and MethodRetention behavior of nabumetone, a model compound was used to optimize these potential lipid membranes using a thin film engineered from 5% Liquid paraffin (LP) as benchmark, while halofantrine, nabumetone , α-naphthol and β-naphthol representing varying molecular polarities, were used for validation studies. The validation involved 2-way analysis of variance (ANOVA) associated with variability in Basic lipophilicity parameter (Rmw), and Specific hydrophobic surface area (SHSA) for the optimized surfaces, relative to LP and octadecylsilane (ODS) Further validation entailed correlation of the lipophilicity descriptor i.e. isocratic chromatographic hydrophobicity index (ICHI) on OL, OL-C, ODS and LP with experimental Log P(octanol/water).ResultsOptimized film thicknesses were produced by 5% OL and 1.25% OL-C (p > 0.05). The 2-way ANOVA revealed great variability in performance characteristics of the surfaces (p < 0.0001), and the new surfaces also gave poorer correlation with Log P values (R2= 0.502 and 0.449 respectively).ConclusionThe 1.25 % OL-C demonstrated a higher biomimetic attribute and warrants further validation studies to ascertain biorelevance, of lipophilicity measurement on this platform, in predicting oral drug absorption. Keywords: Lipophilicity, Reversed-phase Thin Layer Chromatography, Retention behaviour, Olive oil, Castor oi

British Standard and Euro Code: Model of Singly Reinforced Rectangular Concrete Under Actions

Upgrading are desired Changes on any standard in operation. Meanwhile context understanding are required to achieve positive impact on the subject system. In same vein, codes of practice are always revised and that users should be made to use the latest edition of any relevant standard. Thus a model is developed to describe the sectional analysis difference with predicting implications of various combinations of sectional dimensions in structural reinforced concrete elements with reference to the two codes.  The method adopted is purely mathematical technique of modeling, concept and application. Based on the previous behavioural knowledge of such using BS code, Okeniyi et al (2012), a concrete rectangular section of singly reinforced status was also used as a case study. The section was analyzed from stress-strain relationship to formulate the governing equations and the same was specified by breadth b, total depth h and moment of resistance MR. This was simulated to describe the relationship between the variable parameters and predict the behavior of a rectangular section under loads with reference to British Standard and Euro Code. The model, thus defines clearly sectional analysis difference increasing understanding for better structural design skill. Keywords: Reinforced Concrete, Stress-Strain Relationship, Rectangular Section and Moment of Resistance DOI: 10.7176/CER/12-6-05 Publication date:June 30th 202

Effects of Na2Cr2O7 Inhibitor on the Corrosion Potential Response of Steel Reinforced Concrete in Saline Medium

Electrochemical monitoring method of the open circuit potential was used to investigate the effect of the concentrations of Na2Cr2O7 on the corrosion potential response of steel reinforced concrete in sodium chloride medium. In the study, five different concentrations of Na2Cr2O7 admixtures were employed in a system of replicated samples of steel-reinforced concrete specimens partially immersed in 3.5% NaCl to simulate marine and saline environments. Forty days measured responses from these were subjected to the statistical analyses of the Normal and the Weibull distribution functions and tested using the Kolmogorov-Smirnov goodness of fit criteria. Results obtained from the analyses identified 4 g Na2Cr2O7 with optimal averaged potential response inhibition performance by the Normal model which showed better agreements in its models of Na2Cr2O7 potential test data than that obtained from the Weibull model of the same data. These bear pertinent implications on the need for suitability studies of appropriate statistical distribution for studying performance of corrosion inhibitors even as suggestions were proffered for addressing results conflicts among replicates of steel reinforced concrete samples employed

Wind Profile Characteristics and Turbine Performance Analysis in Kano, North-western Nigeria

This study analyzed the electricity generation potential from wind at Kano, Nigeria (12.05°N; 08.2°E; altitude 472.5 m; air density 1.1705 kg/m3). Twenty one years (1987 to 2007) monthly mean wind speed data at a height of 10 m were assessed from the Nigeria Meteorological Department, Oshodi. The data were subjected to different statistical tests and also compared with the two-parameter Weibull probability density function. The outcome shows that the average monthly wind speed ranged from 6.6 to 9.5 m/s. Seasonally, average wind speeds ranged between 6.6 to 8.5 m/s and 7.4 to 9.5 m/s for dry (October to March) and wet (April to September) seasons, respectively. Also, estimated monthly wind power ranged between 3.6 and 12.5 MWh/m2. The most probable and maximum energy carrying wind speeds were also determined and the two parameters of the Weibull statistics were found to lie between 2.1 ≤ k ≤ 4.9 and 7.3 ≤ c ≤ 10.7, respectively. These results indicate that wind speeds at Kano may be economically viable for wind-to-electricity at and above the height of 10 m. In addition, five practical turbine models were assessed for the site’s wind profile, with results suggesting strong economic viabilit

Essential oil constituents of Eclipta prostrata (L.) L. and Vernonia amygdalina Delile

The chemical composition of the essential oils from the leaves and stem bark of Eclipta prostrata (L.) L. and the aerial parts of Vernonia amygdalina Delile (Asteraceae) have been analyzed by capillary gas chromatography (GC) and gas chromatography/mass spectrometry (GC/MS). The investigation led to the identification of 33 and 30 compounds in the oils of the leaves and stem of E. prostrate, respectively, and 40 compounds in the oil of V. amygdalina. While the oil of the leaves of E. prostrata was highly dominated by sesquiterpenoids (89.3%), the stem bark was comprised of sesquiteprenoids (47.7%), straight chain hydrocarbons (25.6%) and monoterpenoids (11.1%). The main constituents of both oils were β-caryophyllene (47.7% and 15.9%) and α-humulene (31.8 and 12.9%) in the leaves and stem, respectively. In addition, ( E)-β-farnesene (10.0%) was also identified in significant amount in the stem bark. On the other hand, the major component of V. amygdalina oil was α-muurolol (45.7%)

Capacity and Quality Assessment of Awba River Basin

This study aims at determining the feasibility of a Mini Water Supply Scheme to meet the growing water needs of The Polytechnic, Ibadan community. The assessment focused on determination of population of the subject community vis-à-vis the location, discharge capacity and quality status of Oba river basin, being the only perennial stream within the community, seeking possible opportunities for capacity building in the areas water based developmental activities. The entire population of the community was obtained by enumeration method with 10years projection considered at a growth of 4 percent on yearly basis. Water budget was arrived at on the basis of per capita per day, in accordance with the United State specification. Raw water supply was obtained through impounding system of reinforced concrete chamber, which serves as an alternative to costly dam construction. Grid survey was carried out to determine the topographical nature along the stream axis at proposed location of the impounding house. Hydrological studies were carried out on the river to obtain its rate of flow and the harvestable volume of raw water at each month of a year. This was used to determine the size of chamber and the impounding hours before pumping. Physico-chemical analysis of the raw water was carried out and the results compared with that of W.H.O’s 1996 guide line for drinking water as to dictate the design of treatment plant and the recommendable chemical dosage. The study thus reveals that the available perennial stream within the community is a resource that could be utilized to alleviate the problem of acute water shortage and create better environment for research and other developmental activities of the institution. Key Words: Population, Raw Water, Capacity and Quality Assessment, Treatment

Self-compacting concrete in pavement construction: Strength grouping of some selected brands of cements

This paper investigates strength properties of some selected cement brands for self-compacting concrete application in pavement construction. Three brands each of Portland limestone cement grades, CEM II/A-L 42.5 (Brand A), CEM II/B-L 32.5 (Brand B) and CEM II/B-L 32.5 (Brand C), were used. Rheological test was carried out using the L-Box, V-Funnel and slump cone while compressivegas emissions from the building sector. These systems require high investments which are returned through the heat sales. Due to the changed climate conditions and building renovation policies, heat demand in the future could decreas