Comparative Toxicity Assessmentof Aqueous and Ethanolic Bark Extracts of Mahogany: Khaya grandifoliolaon Mangrove Periwinkle; Pachymelania aurita

The acute toxicities of extracts of Bark of Mahogany (Khaya grandifoliola) in aqueous and ethanolic solutions were evaluated against the edible periwinkle (Pachymelania aurita) in laboratory bioassays. From the derived toxicity indices, the aqueous extract (96h LC50 = 17.4ml/L, 3.48g/L) was found to be 24.2 times less toxic than the ethanolic extracts (96h LC50 = 0.24ml/L, 0.144g/L). ANOVA showed significant differences in the response of Pachymelania aurita to different concentrations of exposure to extracts at 48hr, 72hr and 96hr respectively. Symptoms of toxicosis observed in the test organisms were immobility and eventually death. Keywords: Toxicity, Pachymelania aurita, Khaya grandifoliola, Edible periwinkle, Lagos lagoon. DOI: 10.7176/JBAH/10-7-02 Publication date: April 30th 202

Traditional Crafts and Tourism Development and Promotion in Etim Ekpo Local Government of Akwa Ibom State, Nigeria.

Many Nigerian communities are richly blessed with their own indigenous crafts and industries, which could help them to grapple with their environment and progressively enhance their living. This paper seeks to identify and document some traditional crafts in Etim Ekpo, with a view to finding out how traditional crafts affects other aspects of the peoples' culture. The paper further examines how best to harness these traditional crafts/industries for tourism development in the area. Our interest on the study area arose due the fact that these traditional crafts/industries are fast being abandoned. It is our contention here that if these traditional crafts are not studied and documented, they will only be remembered in stories and myths as is obtainable in some African countries. Therefore, harnessing the potentials of Etim Ekpo traditional craft for tourism development will stimulate the growth of rural economy, serve as a vehicle for rural community development, create awareness of people's cultural heritage as well as generates employment. Key words:Tourism, Development, Promotion, Crafts, Carving

The Effects of Eggshell Ash on Strength Properties of Cement-stabilized Lateritic

Eggshell ash obtained by incinerating Fowls’ eggshells to ash has been established to be a good accelerator for cement-bound materials and this would be useful for road construction work at the peak of rainy seasons for reducing setting time of stabilized road pavements. However this should be achieved not at the expense of other vital properties of the stabilized matrix. This is part of the effort in adding value to agricultural materials which probably cause disposal problems. Thus this study aimed at determining the effect of eggshell ash on the strength properties of cement-stabilized lateritic soil. The lateritic soil was classified to be A-6(2) in AASHTO rating system and reddish-brown clayey sand (SC) in the Unified Classification System. Constant cement contents of 6% and 8% were added to the lateritic soil with variations in eggshell ash content of 0% to 10% at 2% intervals. All proportions of cement and eggshell ash contents were measured in percentages by weight of the dry soil. The Compaction test, California Bearing Ratio test, Unconfined Compressive Strength test and Durability test were carried out on the soil-cement eggshell ash mixtures. The increase in eggshell ash content increased the Optimum Moisture Content but reduced the Maximum Dry Density of the soil-cement eggshell ash mixtures. Also the increase in eggshell ash content considerably increased the strength properties of the soil-cement eggshell ash mixtures up to 35% in the average but fell short of the strength requirements except the durability requirement was satisfied

INFLUENCE OF HEAD-TEACHERS CONFLICT MANAGEMENT STYLE ON TEACHERS’ JOB SATISFACTION IN PUBLIC SECONDARY SCHOOLS

The study focused on influence of head-teachers conflict management style on teachers’ job satisfaction in public secondary schools in Awka education zone of Anambra State, Nigeria. Two research questions guided the study and two null hypotheses were tested. A descriptive survey research design was adopted. The population of the study consisted 122 head-teachers in 61 public secondary schools in Awka education zone. No sample was taken, as the population size was manageable. A 16-items structured questionnaire validated by three experts was used for the study. The reliability of the instrument was ascertained using Pearson Product Moment Correlation Co-efficient to determine its degree of reliability which obtained overall reliability coefficient values of 0.95. Data related to the research questions were analyzed using mean and standard deviation while Analysis of Variance (ANOVA) was used to test the null hypotheses at 0.05 level of significance. The findings of the study revealed that respondents disagreed that head teachers use integrating conflict management style while they agreed in using obliging conflict management style for their job satisfaction. The study revealed that head teachers’ years of teaching experience does not affect the uses of integrating and obliging conflict management style in their job satisfaction. It was concluded that integrating conflict management style are rarely used by the head teacher. It was recommended, among others, that Head teachers should strive at minimizing conflicts and use appropriate methods to manage them such integrating either than obliging conflict management style.  Article visualizations

Determinants of Volume of POME Generation in Palm Oil Mills for Planning Wastewater Recovery in Biogas Energy Development

Wastewater volume is a necessary prerequisite for planning transformation to valuable resource and averting environmental degradation. This study investigated the dynamics of POME volume generation in palm oil mills in relation to types of fresh fruit bunches (FFBs), seasons, milling scales and volume of crude palm oil (CPO) produced in ADAPALMS and catchment communities, Ohaji/Egbema LGA, Imo State. The eight catchment communities of ADAPALMS were categorised into three strata in relation to the number of small-scale mills in each community (1-5mills, 6-10mills, and 11-15mills). In each stratum, a community was randomly sampled. A total of nine small-scale mills were sampled from the three sampled communities (Ohoba, Amafor and Etekwuru) in proportion to the average number of mills in each stratum. The lone medium and large scale mill (ADAPLAMS) in the study area represented the other scales of milling. For small and medium scale mills, the volume of POME generated was measured from the dimensions of the vessels where POME was stored, while that of large scale mill was obtained from industrial records. Data was analysed using multiple linear regression of SPSS. The volume of POME generated is significantly related to milling scales and volume of CPO produced (p< 0.01); R2=0.788. Within small scale mills, the volume of POME is significantly related to types of FFBs (p< 0.01), different small milling scales (p< 0.05), and volume of CPO produced (p< 0.01); R2=0.762. Thus, these independent variables are the principal determinants of POME volume generation in the area. The result has implication on the necessity of predictive models in managing the dynamics of POME volumes for efficient recovery and transformation of the wastewater to bioenergy

Comparative analysis of aluminium surface roughness in end-milling under dry and minimum quantity lubrication (MQL) conditions

In this study an experimental investigation of effects of cutting parameters on surface roughness during end milling of aluminium 6061 under dry condition and minimum quantity lubrication (MQL) condition were carried out. Spindle speed (N), feed rate (f), axial depth of cut (a) and radial depth of cut (r) were cutting parameters chosen as input variables in the investigation of the surface roughness quality. The experimental design adopted for this study was the central composite design (CCD) of response surface methodology. Thirty samples were run in a CNC milling machine for each condition and the surface roughness measured using Mitutoyo surface tester. A comparison showing the effects of cutting parameters on the surface roughness for dry and MQL conditions in end-milling of aluminium were evaluated. Surface roughness values for MQL condition were lower with up to 20% reduction when compared to dry conditions. MQL cutting condition was found to be better and more reliable because it is environmentally friendly and gives better surface finish. With the obtained optimum input parameters for surface roughness, production oper- ations will be enhanced

EVALUATION OF CHATTER VIBRATION FREQUENCY IN CNC TURNING OF 4340 ALLOY STEEL MATERIAL

In this study, an experimental investigation of chatter in CNC turning for 4340 Alloy Steel material was carried out. Empirical study of chatter and critical cutting condition in CNC turning has been conducted through a well- designed three-factor three-level experiment, and regression models developed for chatter frequency prediction with up to 99.5% accuracy for the material. The arising model and the mean-effect plots of the cutting speed, feed rate, and depth of cut against Signal-to-Noise (S/N) ratio indicates that increasing feed rates and depth of cuts would bring about increase in chatter vibration frequency while high cutting speeds would have attenuating effects on chatter vibration frequency, thereby suppressing it. The percentage contribution of the cutting parameters to chatter vibration frequency established, and optimal machining condition for the machine chatter optimization obtained at a cutting speed of 320 m/min, feed rate of 0.05mm/rev and depth of cut of 0.5mm. The optimal chatter vibration frequency for the turning tests was found to be 130.00 Hz. With the obtained optimum input parameters for chatter vibration frequency, production operations will be enhanced

Ultra-ductile and low friction epoxy matrix composites

We present the results of an effective reinforcement of epoxy resin matrix with fullerene carbon soot. The optimal carbon soot addition of 1 wt. % results in a toughness improvement of almost 20 times. The optimized soot-epoxy composites also show an increase in tensile elongation of more than 13 %, thus indicating a change of the failure mechanism in tension from brittle to ductile. Additionally, the coefficient of friction is reduced from its 0.91 value in plain epoxy resin to 0.15 in the optimized composite. In the optimized composite, the lateral forces during nanoscratching decrease as much as 80 % with enhancement of the elastic modulus and hardness by 43 % and 94%, respectively. The optimized epoxy resin fullerene soot composite can be a strong candidate for coating applications where toughness, low friction, ductility and light weight are important.Comment: 24 pages, 7 Figures, 1 Table in Polymer Testing (2015

Stability Analysis of Model Regenerative Chatter of Milling Process Using First Order Least Square Full Discretization Method

Regenerative chatter is an instability phenomenon in machining operation that must be avoided if high accuracy and greater surface finish is to be achieved. It comes with its own consequences such as poor surface finish, low accuracy, excessive noise, tool wear and low material removal rate (MRR). In this paper, an analytical method base on first order least square approximation full-discretization method is use for the stability analysis on the plane of axial depth and radial depths of cut. A detail computational algorithm has been developed for the purpose of delineating stability lobe diagram into stable and unstable regions using mathematical models. These algorithms enabled the performance of sensitivity analysis. From the results axial depth of cut enhances the unstable region and suppresses the stable region. This means that inverse relationship exists between the axial and limiting radial depths of cut thus highlighting the need to determine the maximum value of their product for achieving maximized MRR thereby reducing the chatter in the milling process. It is also seen that the peak radial depths of cut occasioned by the lobbing effects occur at fixed spindle speeds irrespective of the axial depth of cut. Similarly, the rise in spindle speed enhances the stable region and suppresses the unstable region. This means that for us to have chatter-free milling process, parameters like axial and radial depths of cut should be carefully selected together at high machining speed. With these behaviour, one can locate the productive spindle speed at which the lobbing effects occur and depths of cut combination for the operator