Archives-June... 

Concrete is the major construction material which plays a vital role in the development of current civilization. Construction and demolition waste is one among the various types of waste materials which can be reused in concrete production. Construction wastes are obtained during construction, renovation and demolition of a building. Dumping of these wastes to landfill causes serious environmental issues. The major factor that affects the quality of recycled coarse aggregate which is obtained from construction and demolition waste is the large amount of cement mortar that remains on the surface of it. Hence, it is essential to determine the properties of concrete containing construction and demolition waste as recycled coarse aggregate (RCA). The objective of this study is to develop the equations in order to predict compressive strength of concrete for different cement content with varying water cement ratio using RCA.

The paper considers the problem of designing ESP curriculum for postgraduate students. The role and potential of ESP teaching has a state meaning for Ukraine and many other countries. The key point in ESP teaching is curriculum design. To design a curriculum, the paper determines the postgraduate students’ needs and formulates certain objectives and tasks for postgraduate ESP study. Four content modules are elaborated involving language materials and four types of speech activity.

The present paper deals with the problem of estimating the finite population variance using two-phase sampling scheme in the presence of random non-response. In this paper, we have suggested some families of factor-type estimators of population variance utilizing the information on an auxiliary variable with unknown population variance. The properties of the suggested families of estimators have been discussed in detail. The optimum estimators of the suggested families have also been pioneered out. The theoretical results have been demonstrated through some real data sets. A simulation study has also been carried out to support the theoretical results.

This study is aimed at estimating the sedimentary thickness of the Upper Benue Trough (Nigeria) as revealed by the Aeromagnetic data using the Spectral Analysis and Euler Deconvolution techniques. The area investigated covers from 090 00’ - 100 00’N and from 110 30’ - 120 30’E. An average sediment thickness of 3.98km was estimated which could favour hydrocarbon accumulation and maturation. There is a NE-SW increase in sedimentary thickness which varied from 2.2km to around 5.2km; it is thickest in the NE region. Verification was performed using the Euler deconvolution method which revealed clusters of Euler depth solutions within the low magnetic zones of interest (between 2km and above 3km). Combining both methods implies that a sedimentary depth of up to 4km (to 5km) could be possible especially in the Yola, Mayo Balewa and Bubila regions which thus increase the probability of hydrocarbon maturation and entrapment in these areas.

In this work, we simulate the global solar radiation received by a horizontal surface and vertical surfaces of different orientations on the ground from theoretical models considering the diffusion and absorption of solar radiation through the atmospheric layer. We have to generate results of the global radiation by the model of Liu and Jordan for thermal systems optimization, particularly in the field of the building in the city of Ouagadougou. This work shows that the solar radiation on a surface, in addition to the seasonal variability, also varies according to the orientation and the inclination of the sun. Thus, in the case of buildings, for example, exposing the large surfaces of the building according to the southern orientation will be avoided in favor of the northern orientation. It is also necessary to consider the scenario of use of the building to situate it in space and time in order to minimize the thermal contributions.

Corrosion inhibition of ethanol stem extract of Costus lucanusianus (ESECL) was studied on mild steel and aluminium by weight loss method. The constituents of the extract identified by Gas Chromatography-Mass Spectroscopy (GC-MS) were forty one (41) compounds with 13-Octadecenal, (Z)-(14.39 %) and 9-Octadecenoic acid, 12-hydroxy-, methyl ester, [R-(Z)]- (11.49 %) as the major compounds. Weight loss method revealed that as the concentration of inhibitor increased, the corrosion rate decreased and inhibition efficiency increased. Maximum corrosion inhibition efficiencies of 91% and 85% were obtained in 1 g/l concentration at low temperatures for mild steel and aluminium, respectively. The adsorption followed physisorption mechanism. Positive values of ?H suggested that the process was endothermic, and negative values of ?S suggested a decrease in the disorderliness of the system from thermodynamic approach. The adsorption model showed that Freundlich adsorption isotherm was the best fit for the process.

This study aimed at identifying constraints of yam and soil fertility evaluation and management among smallholder farmers in Kabba/Bunu area. Ten communities were purposely selected and ten yam farmers randomly selected from each community.100 questionnaires were administered to and collected from the farmers. The questions were collated and analyzed using frequency, mean and percentage. 98% of the farmers cultivate white yam and 64% are aware of the existence of improved varieties. Constraints to yam production are lack of access to finance (84%), poor market/sales (71%), availability and cost of seed yam (70%), Lack of access to improved varieties (68%), low soil fertility (64%) and lack of access to fertilizer (56%). Prominent soil fertility indicators are soil colour, crop performance, vegetation type, presence of earthworm activities and topographic position. 59% of the farmers assessed their farm soil to be fertile while 41% is non-fertile. Fertility management practices adopted among the farmers are: mulching (98%), use of legume in intercropping system (62%) and post-harvest residue management (50%). The adoption and cultivation of other varieties of yam apart from white yam, use of organic manure and post-harvest residue management of slash-and-mulch as well as intervention of government and non-governmental organization were recommended.

The study of impact of Distance Education (DE) expanding access and providing quality tertiary education in Ghana has become eminent in the midst of large number of students enrolled in DE institutions. . This paper reviews DE literature with focus on the development of DE in Ghana between 1982 to date. In the context of statistics reviewed from the NCTE, DE is seemingly observed as serving the purpose of access without recourse to quality. The paper draws on the weaknesses and strengths of “access” and “quality” and how each complements the other to ensure effective impact.

Air conditioning system is essential for maintaining thermal comfort in indoor environments, especially for hot and humid climates. Today, air conditioning, comprising cooling and dehumidification, has become a necessity in commercial and residential buildings and many of the industrial processes. It accounts for a major share of the electric energy consumption. Therefore, there is tremendous potential to improve the overall efficiency of the air-conditioning systems in buildings to reduce the uses of energy. In this present research work, begins with a review of the type of losses especially conduction loss, recent novel devices that enhances the energy efficiency. Lastly, the research presents efficient cooling strategies and R-factor of building material with minimization of conduction losses that reduce the primary energy utilization for cooling.

Educational capabilities vary in diverse geographical regions. Training is critical to standardize and optimize educational practices for desired outcomes. In Guyana, indigenous Amerindian preservice teachers need to acquire the skills and overcome the technological barriers to better prepare learners beyond the classroom. Even though internet access would allow indigenous Amerindians in Guyana to develop technology literacy skills and access educational resources, Indigenous pre-service teachers have a low rate of technology adoption in the classroom. The purpose of this basic qualitative study was to discover the perceptions of indigenous Amerindian preservice teachers on the adoption of digital technology in the classroom. Rogers’s diffusion of innovation theory and David and Venkatesh's technology of acceptance model were used to understand indigenous Amerindian preservice teacher perceptions about the use of digital technology, in respect of perceived barriers, and the coping and adopting mechanism throughout their pedagogical practices. Ten Indigenous Amerindian preservice teachers participated in this qualitative study. Semi-structured, interviews were the primary data collection tool. Open coding was used to generate themes and analyzed emergent coding. The findings from this study indicated that the rate of adoption of digital technology could accelerate if (a) training is strategic, (b) there is a reduction of institutional barriers, and (c) professional practices are aligned for educational growth. This study potentially contributes knowledge to education and leverage and adoption of digital technology, to advance understanding of learning and pedagogical best practices. The findings may contribute to positive social change in that professional development centers can improve skills that provide flexible learning for improving access to psychological therapies to integrate digital technology beyond the classroom. and serve as a catalyst to promote growth by capacity building.