Contamination of the geoenvironment due to unsafe waste disposal practices and leakage from waste repositories is a well-known and widespread problem. Emphasis has therefore been put on the hydraulic properties and contaminant transport capability of materials proposed for use as barriers in such facilities. Consistent with the current approaches f... Continue Reading
The possible dependence of the extrapolated ranges of electrons on the detector characteristics has been investigated by two methods. These experiments were performed under well standardised geometrical conditions, employing electron beams (0.25 - 0.75 MeV) derived from a Van de Graaff electrostatic generator. The possible effects of poor geometry ... Continue Reading
This research was carried out to investigate the effect of elapse time after mixing on the geotechnical properties of soil-lime-bagasse ash mixture. Preliminary investigation on the black cotton soil used showed that the soil belongs to A-7-6 and CH in the AASHTO and Unified Soil Classification System (USCS), respectively. Soils in these groups are... Continue Reading
This research studies the propagation prediction variations of three models over a Nigerian urban environment and the development of a suitable propagation prediction model for the environment. The measurements of the received signal strength at various distances for nine base stations were conducted at Celtel,Kano. The measurement equipment used c... Continue Reading
Austempering heat treatment practice helps in achieving high strength with good ductility and toughness by evolving a predominantly bainitic or ausferritic microstructure in steels or cast irons respectively by using salt bath. The potentials of using fatty-based vegetable oils as quenching media for austempering of steels, and cast irons have been... Continue Reading
Steel fibre mortar and concrete are composite materials made with introduction of steel fibres into cement-based materials within certain percentage of fibre. Steel fibre mortar and concrete had improved properties when compared to plain mortar or concrete. In this work; three types of fibres namely - Circular Steel fibres (CSF), Rectangular Steel ... Continue Reading
An expansive black cotton soil taken from a borrow pit located along Numan �“ Ngurore road in the North Eastern part of Nigeria was treated with an agricultural waste ash produced from the burning of the husks of ripe fruits of the African Locust Bean tree that are abundantly available in Nigeria. The soil was classified as A-7-6 and CH in accorda... Continue Reading
Theoretical, evaluations of ammonia - water heat pump systems for various applications and the construction and experimental evaluation of absorption heat pump for cooling is presented. The theoretical evaluations include; (i) theoretical evaluation of the various tracking modes as a means of solar energy augmentation for solar flat plate collector... Continue Reading
The utilisation of cotton plant stalks for papermaking, as an alternative to the wasteful disposal of the crop residue by burning, was explored in this study, using four varieties of American upland cotton plants (Gossypium hirsutum), namely: SAMCOTs 6, 8, 9 and 10 grown in Nigeria. Wood and bast fibre characteristics, such as fibre wall thickness,... Continue Reading
To eliminate pod-picking, it has become necessary to replace the conventional cowpea (Vigna unguiculata (L.) Unlp) pod thresher with whole shoot thresher. This research work deals with selected physical and mechanical properties of cowpea stalk, pod and grain, as related to the mechanical threshing of the entire cowpea shoot. In the study it was fo... Continue Reading
This experimental investigation was carried out to determine the strength of concrete confined by plastic pipe and the effect of slenderness ratio on the strength. Pipes of 75mm and 100mm diameters of varied lengths: 410mm to 1210mm were used. Two different concrete mixes were tested: a 1.5 sand-cement ratio and 3 coase aggregate cement ratio. The ... Continue Reading
A theory for the design of reinforced concrete short cantilever under pure torsion is presented. It is based on the shear-friction theory. The failure plane assumed is supported by observations on test-specimens. Based on the failure surface, the failure torque was found to be primarily a function of percentage of longitudinal reinforcement, dimens... Continue Reading
Fixed stops and Hail stops are among the possible mode of service used in intra-urban transit. Under the fixed stop service, vehicles stop to load or unload passengers at designated points only. For the hail stop service vehicles stop to load and/or unload at any point along the route on demand by patrons. The relative performance of fixed stop and... Continue Reading
Wind loading estimation is one facet of the entire design process. Wind speed as a climatic process which is time-dependent requires proper assessment in order to predict its speed for specified return periods. This requires a good understanding of the wind process within the lower atmosphere (where the designer of civil engineering structures has ... Continue Reading
Quality and standardization of all construction materials are of paramount importance and serve as yard sticks for measurement reflecting the level of development attained by a nation. Sandcrete hollow blocks are construction materials which have gained wide acceptance and use in the construction industries because of the many characteristics prope... Continue Reading