Study of Mechanical Properties of Stabilized Lateritic Soil with Additives.

The overdependence on the USAge of industrially manufactured soil improved or conventional additives have resulted in unaffordable cost of construction of better infrastructure in Third World and poor countries which are mostly agriculturally dependent across Globe. This study is aimed at studying the mechanical properties of lateritic soil stabilized with mixture of conventional and locally available additives. Soil samples collected from the study area were subjected to laboratory tests (i.e. Grain Size and Atterberg Limits tests) after stabilized with cement, ESA and RHA additives at proportion of 2% to 10% by sample weight. It is observed that the LL, PL and PI values varied from 30.1% to 35.5%, 9.9% to 12.5% and 20.1% to 23.2% respectively for sample A. While LL, PL and PI values varied from 35.2% to 41.5%, 10.8% to 14.5% and 24.4% to 27.1% respectively for sample B. It could be generally observed that PI values reduced while PL values increased for the soil samples after increase in addition of cement additive from 6% to 8%. All the LL, PL and PI values also reduced as the percentage of RHA additive added increased. Soil sample A has group classifications of A – 2 – 6 while soil sample B has A – 7 and tend towards A – 2 - 6 and A - 6 after stabilization. The stabilization process using local additives as partial replacement of conventional one generally improved the soils Engineering properties. Though it is more felt in ESA than RHA. Further research work should be carried out

A generalisation of the Hill's quadratic yield function for planar plastic anisotropy to consider loading direction

© 2017 The Authors In this work, a new generalised quadratic yield function for plane stress analysis that is able to describe the plastic anisotropy of metals and also the asymmetric behaviour in tension-compression typical of the Hexagonal Closed-Pack (HCP) materials, is developed. The new yield function has a quadratic form in the stress tensor and it simultaneously predicts the r-values and directional flow stresses, which is shown to agree very well with experimental results. It also accurately describes the biaxial symmetric stress state which is fundamental for the accurate modelling of aluminium alloys. The new quadratic yield function represents the non-symmetric biaxial stress state by performing a linear interpolation from pure uniaxial loading to a biaxial symmetric stress state. The main advantages of this new yield function is that it can be used for the modelling of metals with any crystallographic structure (BCC, FCC or HCP), it only has five anisotropic coefficients and also that it is a simple quadratic yield criterion that is able to accurately reproduce the plastic anisotropy of metals whilst using an associated flow rule

Computer Self-Efficacy of Librarians and Users as Influencers of University Libraries’ Information System Security: Evidence from Nigeria

Librarians and their users interact with the library’s information systems for different reasons. The need to protect information and information systems from unauthorized access, modification, data loss and destruction by librarians has become topical in recent times, hence this study. Using survey research design of the correlation type, three University libraries in the South-western Nigeria were purposively selected. Structured questionnaires for 48 librarians and 44,508 registered library users were used. Proportionate stratified random sampling technique for library users with Undergraduates, post graduates and staff as the basis for stratification was used. Total enumeration was used to capture all the librarians, total of 845 (95%) for library users and 42 (88%) for librarians were successfully completed and used for the study. Findings revealed that the librarians and library users had high computer self-efficacy levels related to information system security. Furthermore, computer self-efficacy of librarians significantly influence information systems security (β = .61, t= 4.86, p.05). The study concludes that these two groups have a strong belief in their abilities to use computers effectively to impact on the information system. The librarians’ belief is in the positive; the users’ appears to be for negative reasons. The study recommends very high level of computer and other technologies efficacy for librarians, regular training and retraining while users should be re-orientated to the realities and benefits of secured information systems

Evaluation of the Efficacy of African Basil (Ocimum gratissimum) Leaf for Disinfecting Well - water obtained from Ekiti State, Nigeria

The demand for potable and affordable water led to comparative research of the efficacy of Ocimum gratissimum Leaf (OGL) extract by collecting well water and treated with OGL extract. Both treated and untreated samples were subjected to physiochemical and bacteriological examinations. Data obtained showed that the pH and feacal coliform counts ranged from 6.17 to 6.74 and 0 to 192 CFU/100 mL for well water sample A; 6.56 to 7.24 and 0 to 118 CFU/100 mL for well water samples B; 6.81 to 7.79 and 0 to 75 CFU/100 mL for well water samples C respectively. The OGL extract includes various bioactive components (i.e. steroids, tannins, etc) according to the phytochemical tests. The first feacal coliform count was above the allowed range (i.e. >50 CFU/100 mL) and the pH value tended to be acidic (6.5), with a colour of >15 H.U. and an unclear (brownish) appearance. The Coliform count was lowered with each dosage of OGL extract until it reached zero count after 24 hours’ contact time at an optimum dosage of 5 mL and the total bacteria counts were gone. The beneficial influence (s) from this study confirms the disinfectant potential of OGL extract for well water treatment

A new generation of spaceplanes is taking advantage of the latest in technology

This article is republished from The Conversation under a Creative Commons license. Read the original at https://theconversation.com/a-new-generation-of-spaceplanes-is-taking-advantage-of-the-latest-in-technology-222307 .Nasa’s space shuttle operated in low-Earth orbit for 30 years before its retirement in 2011. However, the US space agency’s replacement for this vehicle, Orion, returned to the conical capsule design familiar from the Apollo missions. This was because Nasa intended that this newer craft be used for exploring targets in deep space, such as the Moon

Personality Traits, Perceived Stress and Social Network as Predictors of Alcohol Addiction among Youths in Ibadan, Nigeria

The challenge of alcohol use among youths  has been on the increase and the problems are manifested to the individual, the family and the society at large. One such problem is alcohol addiction which has been investigated using different predictors with varying results. Therefore, this study re-examines personality traits, perceived stress and social network as predictors of alcohol addiction among youths in Ibadan, Oyo State, Nigeria. The study adopted cross-sectional survey design while data was collected from 384 youths (males 282, females 102) using validated questionnaires. Data collected were analyzed using zero-order correlation, t-test of independent samples and multiple regressions analysis. Four questions were tested and the results were accepted at a p < 0.05 level of significance. The results showed that personality traits (r = 0.168, p < 0.05) and social network (r = .057, p < 0.05) positively correlated with alcohol addiction while perceived stress negatively correlated with alcohol addiction [r = - 0.029, p < .05]. Also, the result revealed that perceived stress significantly influenced alcohol addiction among youths (t [383] = 0.213, p <. 0.05). However, social networks did not significantly influence alcohol addiction among youths in Ibadan (t [382] = .026, p >. 05). Finally, the results showed the combined effect of personality traits, perceived stress and social network as joint predictors of alcohol addiction among youths in Ibadan [R2= .125, F [5, 378] = 10.771, p < .05). The study concluded that personality traits, perceived stress and social network are good predictors of alcohol addiction among the study participants. The study recommended that mental health workers should carried out personality profiling, used stress therapy and design targeted adverts to help youths who are suffering from alcohol addiction

Household Hazardous Waste Management in Sub‐Saharan Africa

Household hazardous wastes (HHWs) have not been given serious attention in sub‐Saharan Africa. There is little or no information on HHWs in many developing countries of the world. This is regardless of the fact that they are very toxic and contain constituents which are persistent in nature. Once released into the environment, they can remain stable for exceptionally long periods of time. They have the potential to be harmful to public health and the environment if not handled, used, and disposed properly. This study reports the level of knowledge and management of HHWs in three tertiary institutions in sub‐Saharan Africa. Several factors were found to be responsible for poor management of HHWs. These include lack of awareness, inadequate treatment technologies, financial constraints, lack of realistic policies and legal frameworks, and unplanned settlements, among others

Kinetics and mechanistics steps to the electron transfer reaction of peroxo-bridged binuclear cobalt(III) complex of succinimide by glycine in aqueous acidic medium

ABSTRACT. The kinetics and mechanistic steps to the electron transfer reaction of the peroxo-bridged binuclear cobalt(III) complex of succinimide [(suc)(en)2Co(O2)Co(en)2(suc)2+] hereafter called peroxo-bridged dicobalt(III) complex ‘[Co(O2)Co2+]’ by glycine have been carried out spectrophotometrically at λ = 420 nm and T = 26 ± 1 oC, [H+] = 1 x 10-3 M and ᶙ = 0.5 M (NaCl) in aqueous acidic medium. The reaction was found to be first order with respect to [Co(O2)Co2+] and [(Gly] and experimental data indicates a second-order overall. The reactions obeyed the general rate law: (d[Co(O2)Co2+]/dt) = (a +b)[H+])[Co(O2)Co2+][Gly]. Varying hydrogen ion concentration accelerated the reaction rate and shows first-order dependence while the reactions also affected by changes in the ionic strength of the reaction medium by giving a non-negative salt effect in the course of the reaction. Free radicals were not detected in the reactions. Spectroscopic investigation and Michaelis-Menten plots suggest the absence of intermediate complex formation. The experimental result obtained in this system is concluded in favor of the outer-sphere mechanism.                     KEY WORDS: Cobalt(III) complex, Kinetic, Electron transfer, Spectroscopic, Mechanistic steps, Michaelis-Menten, Glycine   Bull. Chem. Soc. Ethiop. 2021, 35(2), 425-434. DOI:  https://dx.doi.org/10.4314/bcse.v35i2.1

Characterization of a thermostable Bacillus subtilis &#946-amylase isolated from decomposing peels of Cassava (Manihot esculenta)

&#946-Amylase (á-1, 4 glucan maltohydrolase; E.C:3.2.1.2) is used in the food processing, brewing and distilling industries due to its capacity to produce maltose syrup from starch. Here, we report the purification and characterization of â-amylase from Bacillus subtilis isolated from cassava peel waste obtained from a milling factory in Ikenne-Remo, Ogun State, Nigeria. The enzyme was extracted, fractionated at 90% (NH4)2SO4 and further purified using DEAE-cellulose ion exchange chromatography. The molecular weight of the purified enzyme was estimated to be 34.67 Kd. The specific activity of the partially purified enzyme was approximately 1.35 units per mg of protein (Umg-1), Kinetic analysis of its starch hydrolysis activity gave a Km value of 2.496 ± 0.025% and a Vmax of 1.136 ± 0.055 units min-1. The optimum pH and temperature were determined to be 5.5 and 70 0C respectively, and the thermal stability curve gave a maximum activity of 9.75 U at 70oC for 60 min of incubation. Bacillus subtilis â-amylase is valuable for maltose production, which can be hydrolyzed further by other groups of amylase for the production of high cassava glucose syrup used as sweeteners in the food industry