nigerian defence academy
journal of science and engineering (ajse)
PARTIAL REPLACEMENT OF SAND WITH FOUNDRY SAND IN BAGASSE ASH CONCRETE
F.O.P. Oriola and G. Moses
This study examines the feasibility of the partial replacement of fine aggregate in Bagasse Ash Concrete (BAC) with foundry sand’ an industrial waste produced from foundries. Preliminary trial mixes were cast and tested to confirm the optimum proportion for the replacement of Cement in Ordinary Portland Cement (OPC) Concrete with Bagasse Ash, 20 % Bagasse Ash(BA)replacement of Cement was found to be practical and was therefore adopted. Then, the sand in the adopted mix was replaced by foundry sand in proportion of 20 %,40 %.60 %.80 % and 100 % of the sand. The compressive strength at 28 days of the BA/OPC concrete dropped by about 24 % at 20 % BA replacement. A further decreased in strength of about 15% of ire original strength of the OPC concrete was obtained for a mix ratio 40 % replacement of sand by foundry sand; the 40 % markwas considered practical. This result was obtained for a mix ratio of 1.6 1:1 w5. However at 365 days, the compressive strength of BA/OPC concrete did not shon any sensirivin' to the proportion of sand replacement, as the compressive strength obtained we ::i sign: ncantiy different from that obtained for the case ofno replacement. It can be inferred th a: s:. 5 j:;: :: o n o' s an a - \ i th fo undry sand in Bagasse ash/.Cement concrete is possible as long as the replacement sropo'iion does not exceed 40 % foundry sand replacement in a concrete mix with not more than 1 :: 3 A repl icement of OPC but the attendant reduction in strength of about 40 % will need to be la-ien into consideration. Finally, the economic benefit of replacing core concrete material ach:-;in inis research work can be considered enormous on the basis of the high percentage offc: naw sand recorded as a replacement material for sand..
A COMPARATIVE STUDY OF BIODIESEL PRODUCED FROM SOME VEGETABLE AND WASTE OILS IN KADUNA.
Aliyu, Adetutu Oluwakemi
Mango seed oil, used vegetable frying oil, orange seed oil, corn oil and soybean oil were converted into respective methyl esters known as biodiesels. They were prepared in the presence of homogeneous alkaline catalyst. The physicochemical properties such as density, flash point, kinematic viscosity, cloud point, pour point, cetane number, fire point, acid value, pH and percent yield were determined and the value obtained compared with biodiesel standards (ASTM D6751, Enl4213, ANP 42, IS 15607, JASO M360, & SANS 1935). Biodiesels obtainedfrom mango seed oil, used vegetable frying oil, orange seed oil, corn oil and soybean oil methyl esters were of good quality and could be used as dieselfuel.
SMALL SIGNAL STABILITY ANALYSIS OF A 330KV NETWORK: A CASE STUDY OF THE NIGERIAN 330KV NETWORK
Ogonjiyigbe J. K , Gonoh B.A.
This paper, examines the stability of the existing 330kV Nigerian network system when subjected to small disturbance such as gradual load and generation increase. Modal analysis method is employed to carryout the analysis using the NEPLAN software. Various scaling factors for load and generation ranging from 0.4 to 0.6 andfrom 0.6 to 2.0 respectively were used to test the stability ofthe system. The results showed that all the generating nodes have negative real parts ranging from -0.001 to -1.404 and damping ratio from 0.054 to 0.211 which falls within the acceptable value of 0.3 and above with the exception positive eigenvalue to the negative side ofthe complex plane (S-plane).
ERGODICITY OF QUANTUM STOCHASTIC DYNAMICS
Noncommutative Lp space technique is applied in this analysis of a dissipative quantum dynamical semigroup with a view of addressing the question of ergodicity of the dynamics Pi over a von Neumann algebra M involving operators of the form x. .
HIGH-ORDER BLOCK METHOD FOR DIRECT SOLUTION OF SECOND ORDINARY DIFFERENTIAL EQUATIONS
AM BADMUS and FE EKPENYONG
IMPACT STRENGTH AND TOUGHNESS PROPERTIES OF POLYMER MATRIX COMPOSITES DEVELOPED FROM FIBRE GLASS/3-D COTTON
FIBRE AND EPOXY RESIN
Jacob Olaitan AKINDAPO, Adeyinka Kofoworola OYINLOLA, Oladipo
FolorunshoAGBOOLA, and Mohammed Kabir YAKUBU
The impact strength ofpolymer matrix composites developedfrom fibre glass, 3-Dimensional cotton fibre and epoxy resin has been investigated in this work. The polymer matrix composites were producedfrom two fibres (fibre glass and 3-dimensional cotton fabrics) and epoxy resins (bisphenol- A-co-epichlorohydrine). The epoxy resin was produced by dissolving a measured quantity ofsolid and liquid Bisphenol-A-co-epichlorohydrin in Acetone. Three different amines (Diethylenetriamine (DETA), Triethylenetetramine (TETA) and Tetraethylenepentamine (TEPA)) were used as curing agents for the production work. The result shows that impact strength of polymeric materials depends heavily on the type of fibre used, the amine/epoxy weight ratio, epoxy/fibre weight ratio, thickness of the fibre and the use of additives as property modifiers. The toughness properties were deduced from the tensile properties by computational methods. Toughness properties were found to decrease as the ratio of amine to epoxy increases when DETA and TEPA were used as amines. The toughness properties increases as the ratio of epoxy to fibre increases when DETA was u~ed. Compounding with High Density Polyethylene (HDPE) and Nitrile Butyldene Rubber (NBR) drastically increased toughness by 30% for most of the samples developed. Impact strength increases as the thickness of the fibre glass increases. The composite material developed has an average toughness property of 29.25 joules/mm and impact strength of57.5joules/mm.
OPTIMAL COMPARTMENTALIZATION OF N-TEAM INTERACTING MODEL FOR DECISION MAKERS WITH BOUNDED RATIONALITY CONSTRAINS
The work of Oladejo (1995) which extended the result of previous investigations of Levis and Boettcher found that hierarchical command organization diminishesin efficiency and thereby increases the workload of the last (N')decision maker (N DMjwill be summarised. Decision Centres are recommended for adaptation in order to remedy the anomaly arising from the effects of the imposed (if) colossal constraints that were found in Oladejo (1995). The remedial procedure being considered in this work found that an optimal C l system exists when considering 2 teams or n-2,
i.e.2DM's in cell-team command. Also in this work the optimal economic compartmentalization of SDMs was also found.
REPLACEMENT VALUE OF LOW-GRADE CASSAVA MEAL (GARI) FOR MAIZE IN THE DIETS OF PULLETS
VANTSAWA PHILIP ANTHONY
An experiment was conducted to evaluate the nutritional value of low-grade cassava meal (gari) in the diets ofpullets, one hundred and eighty (180) pullets at nine weeks of age and approximately equal body weight (0.65kg) were randomly allocated to six dietary treatments. There were six dietary treatments in which gari replaced maize at graded levels of0.00, 10.00, 20.00, 30.00 and 40.00% with treatment one as control and treatment six having maize replaced by 100% gari (58.90%). The results showed that feed consumption significantly (P<0.05) reduced as the level of gari increased in the diets. However, no significant difference (p>0.05) in weight gain was observed between control treatment up to treatment four with 30% replacement of maize by gari. Feed conversion ratio and percent mortality did not show any significant difference (P>0.05). The cost N/Kg gain reduced significantly (P<0.05) from control to treatment four beyond which higher level of inclusion did not confer advantage. Therefore, there was an economic advantage of using gari as replacement for maize in the diet ofpullets up to 30% since N53.31 savings was made for every kg gain in body weight of the birds.
PERFORMANCE INDICES AND EVALUATION OF ATM SERVICES IN MUBI: A FACTOR ANALYTIC APPROACH
Fache, V.O., Medugu, I.J., Tarfa, S.A.
Electronic banking is becoming prominent in all banking operations. With widespread use of Automatic Teller Machines (ATMs) banking halls have seriously been decongested as the growing population of customers now obtain fast, reliable and efficient self-service at any nearest ATM outfit. On the other hand it has been observed in recent years that while some banks are gaining competitive advantage over others with successful deployment of ATMs others are closing ATMs down due to deplorable service conditions and poor customer patronage. This study is therefore aimed at identifying the factors/indices that could enhance the performance of ATM services. The population comprised of bank customers in Mubi, Adamawa State, Nigeria who use ATMs. The sampling frame technique was applied and 9 banks that deployed A TMs were selected. Data collection instrument was a structured questionnaire administered to 270 users of ATM cards. Principal Component Analysis was adopted in the data analysis. The results obtained revealed that four factors, namely quality of infrastructure, response time, reliability of service and cost of service are the major factors that influence users' patronage. To increase customers’ patronage of ATMs, it was recommended that banks should exploit these indices at the planning to enhance their performance.
FREE VIBRATION ANALYSIS OF EULER-BERNOULLI BEAM USING DIFFERENTIAL TRANSFORMATION METHOD
Agboola, O.O. and Gbadeyan, J.A.
Using differential transformation method, the analysis of the free vibration of a prismatic Euler- Bernoulli beam under various supporting conditions is carried out in this study. Some numerical examples are presented to demonstrate the efficiency and reliability of the method. The results obtained are in good agreement with the results obtained in available literature using different approaches. These results show that the technique introduced here is accurate and easy to apply.