nigerian defence academy
journal of science and engineering (ajse)
THE FOOD AND FEEDING HABITS OF TWO MORMYRID
SPECIES IN RIVERS KADUNA, NIGERIA
The food and feeding habits of Mormyrops deliciosus and Mormyrus rume in River Kaduna was investigated from June 1997 to May 1998. The two Mormyrids were observed to feed mainly on insects and plant materials. Other supplementary food materials included algae, sand, detritus, prawns, seed and other fish species. The occurrence of the food items varied with the seasons. The presence of benthic materials in the stomach was an indication of their benthic made of feeding. Presence of fish material in larger fishes indicated variation in feeding with the size of the fish..
NUTRIENT COMPSOTION OF COCOYAM
(XANTHOSOMA SAGITTIFOLLIUM (L) SCHOTT.) COOKED
WITH LEAVES OF ANTHONATHA MACROPHYLLA
ENOMFOM J. AKPAN AND BASSEY S. ANTIA
The proximate composition, minearal elements and anti-nutrient factors of the leaves of Anthonotha macrophylla (family: fabacceae) and cocoyam (Xanthosoma sagittfolium (L) Schott.) subject to different cooking conditions were determined.
The leaf of A. macrophylla contains appreciable amounts of fat, moisture, ash, fibre, and carbohydrate but less protein. The leaf is rich in sodium, magnesium, calcium, iron, manganese, zinc and copper. The leaf also contains high amount of axalate and tannins. The Xanthosoma sagittifolium was by sensory evaluation found to cause throat irritation on consumption of the cooked sample. Results showed general increase in the moisture, ash, crude protein, fat, fibre and carbohydrate contents of the cocoyam cooked with the leaves of Anthonatha macrophylla compared with the uncooked sample. Significant difference (p<0.05) in mineral concentration was observed in samples cooked with the leaves. Calcium reduced from 26.67% in the uncooked to 24.76% and increased from 26.67% in the uncooked to 29.33% in the sample cooked with leaves of A. macrophylla. Magnesium, Sodium, Potassium, and Phosphorus showed similar reductions. Iron content was 9.33% in the uncooked sample, 17.60% in the sample cooked without leaves, and 17.07 and 10.67% in the samples cooked with the leaves of A. macrophylla. Total axalates reduced considerably from 1180% in the uncooked to 734.20% and 849.20% in the samples cooked with the leaves of A. macrophylla respectively. Tannins, hydrocyanin and phytic acids showed similar decreases for samples cooked with the leaves. The above results imply that cocoyam nutrition could be improved through the use of chap and locally available processing methods aimed at reducing toxicity and throat irritation.
INVESGTIGATION OF PROTEIN QUALITY OF SOME FRESH WATER FISH
SPECIES OF NORTHERN NIGERIA
S.A. Abdullahi and D.S. Abolude
Studies on the protein and amino acid qualities and quantities of Mormyrops deliciosus. Bagrus bayad, Synodontis budgetti and Hemichromis fasciatus collected from Tiga dam, Zaria dam, Shiroro dam and Niger – Benue confluence were carried out using standard methods and the Technicon Sequential Multi sample Amino acid analyzer (TSM - model 1). Analysis of whole body showed high moisture contents (72.30 – 78.80g/100g) wet weight, organic matter (7.5 – 86.4. g/100g) protein (37.1-46.12 g/100g). H. fasciatus contained the highest protein which was significantly higher (P<0.05) than in B. bayad. Glutamic acid (14.70-17.04 g/16N) dominated the pool in all four species and was significantly higher (p<0.05) than any other amino acid. The essential acids, lysine, histidine, arginine, threnine, alanine, valine, methionine, Isoleucine, leucine, tyrosine and phenylalanine were in concentration above the FAO/WHO reference values. The chemical indices, E: N%, E:T%, EAAI%, C.S/PS% and E:P% all indicated protein of high quality in reference to the FAO/WHO reference values. The four species are sources of good quality proteins, especially for weaning infants.
ZINC AND COPPER STATUS OF ORCHARD SOILS DERIVED FROM
SEDIMENTARY ROCK IN SOUTHERN GUINEA SAVANNA REGION OF
P.A.E. AKO, M.I.S. EZENWA AND J. YISA
Fifty-four samples of soils under citrus (Citrus sinesis), mango (Mangifera idica) and cashew (Anacadim Occidentale) plants were analyzed for their total and HCl - and EDTA – extractable zinc and copper. Correlation studies shows significant relationship between these parameters and some selected soil properties. Comparison of properties of soils under orchard soils showing higher levels. In general, low to very low levels of the soil properties and total extractable zinc and copper were found.
FURTHER STUDIES ON THE ANALYSIS OF COLD COLOUR DURATION
IN THE SAHEL REGION OF NORTHERN NIGERIA
Further studies on the relationship between Cold Cloud Duration (CCD) and amount of rainfall in the Sahel region of Northern Nigeia is discussed. The analysis is carried out under daily, pentade, decade and monthly basis. Six linear regression equations were considered. Under daily and pentade basis, the regression equation, Y - = A + BX, showed most efficient performance than the others and under the same basis the equation, Y = X/A+BX)
ITERATIVE ESTIMATION OF A TRAFFIC DISTRIBUTION
FUNCTION FOR BUS PASSENGER FLOWS FROM
The study examines the performance of an interative model (the interative weighted Least Squares model) in terms of its ability to estimate the coefficient of a distribution function as well as its ability to replicate actual bus passenger flows from Kaduna to other towns in Nigeria. The results from the interative technique were also compared with those from the ordinary least squares (OLS) method. The OLS model was specified in both linear and log-linear format. The results obtained show that the integrative model produced statistically more significant parameters than the OLS models. However, in terms of simulation capability, the OLS model, specifically the log linear model performed slightly better than the iterative model. Nonetheless, given the possible problems with the data obtained, the iterative approach is preferred both for parameter estimation and the simulation of flows.
PROBABLE ORIGIN AND CONTROL OF AGULU-NANKA GULLY EROSION IN EAST CENTRAL NIGERIA
E.A. EMENIKE AND D.N. OBIORA.
ABSTRACTThe Agulu-Nanka gully is the most prominent erosional feature in East-Central Nigeria. It probably originated from horizontal compression beneath the crust aided by the presence of a large volume of unconsolidated formation. The control of the gully erosion has been a source of nightmare to successive agencies concerned over the years. The control measures adopted in the past range from planting of relevant trees in the vicinity of the gully to construction of the ditches and slumps and more recently channels to lead the floor water to the nearby Odo River. These measures failed because they are not informed by data based on the geology, geo-technology and hydrogeology of the area. An effective control measure must be based on an erosion model in which data from the aforementioned and the erosional factors are integrated. The model suggests the need for the excavation of loose Nanka sands and refilling with concrete material in vicinity of gully front and constructions of network of channels that will withstand 4m- wall of floodwater away from the gully front to the Odo River.
TRANSVERSE ELECTRICAL RESPONSE OF CHEMICALLY DEPOSITED
PbS AND Cu2S THIN FILMS IN THE ABSENCE OF AN EXTERNAL MAGNETIC
The observed transverse electrical response of chemically deposited thin films of PbS and Cu2S in the absence of an external magnetic field when a dc voltage is applied is reported. By the use of the specially designed high-precision TRM-2x2 devise, it is established that these semi-conducting thin firms are a “2-way” ohmic substances which exhibit some degree of rectification on reversing the “polarity”. Certain semi-quaiitative factors which may assist in unveiling the origin of this phenomenon is highlighted.
EFFECT OF ENVRIONMENTAL FACTORS ON THE PERFORMANCE OF
LOCALLY CONSTRUCTED ELECTRIC GRAIN MOISTURE METER
S.A. AJAYI AND M.O. OBAFUNMI
The need for rapid, efficient and accurate method of moisture determination of agricultural food grains that will be at the reach of the Nigerian farmers prompted the idea of a locally constructed electric grain moisture meter based on the principle of “Marconi” moisture meter which is imported. The construction was done using 100% locally sourced materials. The meter calibration against oven method shows a perfect positive correlation (r = i). The effect of environmental factors such as air flow, sound, sunlight, altitude, temperature and humidity on the meter performance were also studied. The result shows that there was no significant difference in all the parameter examined except for temperature which shows a stable reading up to 250C but between 250C and 400C, the value were affected.
ANALYTICAL CAPABILITY OF NIGERIA RESEARCH REACTOR-1 (NIRR-1)
S.A. Jonah, G.L Balogun, I.I. Umar, A.L. Obi and H.B. Garba
At the Centre for Energy Research and Training, Ahmadu Bello University, Zaria, Nigeria’s first research reactor facility is being installed for education and training. In this paper, the characteristic features of the low-power reactor associated with its utilization for neutron activation analysis and radioisotope production are described. Analytical prospects with the facility vis-à-vis experimental programmes based on thermal neutron activation analysis procedures are discussed. Considering a thermal neutron flux of 1012n.cm-2 S-1 at full power, the calculated analytical sensitivities for 67 elements are presented.
AN ASSESSMENT OF THE POWER TRANSMISSION
CAPABILITY OF THE EXTERNAL ROTARY GENEVA MECHANISM
CHRISTOPHER O. IZELU
The dependence of torgque transmission ratio on input crank speed and on geometric parameters of the external rotary Geneva mechanism is investigated. A computer oriented numerical approach is utilized. The results obtained showed that torque transmission ratio is not dependent on the input crank speed, but is dependent on the geometric parameters. In other words, the capacity of the mechanism for power transmission is limited only by the size of the input crank and by the negative effects of shock loads associated with high speeds.
PERFORMANCE ANALYSIS OF A SPARK-IGNITION (SI) ENGINE
DEPARTMENTOF MECHANICAL ENGINEERING, ABU, ZARIA
D.S. Yawas and A.I. Obi
The effects of heat on the performance of spark-ignition (SI) engine at part-throttle and full-throttle have been investigated by varying the speed of operation and measuring heart input from the same quantity of fuel, the brake thermal efficiency, the brake horse power, the torque and the speed using PETTER water-cooled petrol engine at part and full throttle positions. The results show that as the heat supply increased at both part and full throttle positions, the brake thermal efficiency increased. It is also advantageous for an engine to operate at part throttle position because the engine attains higher efficiency with low supply of heat.
REVIEW OF SOME SIGNAL PROCESSING METHODS WITH REFERENCE TO
A BIOMEDICAL SIGNAL
Ashiru Sani Daura
The field of signal processing provides methods for the feature extraction, refinement and analysis of all types of signals. Different methods are more suitable for different signals, depending upon the properties of the signals and features to be extracted for the and studied. In this study, a biomedical signal – heart sound signal – is analysed using various methods, with a view to identifying the most effective. At the end the time frequency and wavelet transform were found most suitable for the study of this type of signals.
MODELLING RADIATED ELECTROMAGNETIC INTERFERENCE
FROM INFORMATION TECHNOLOGY EQUIPMENT
Engr. Dr. U.G. Danbatta
Electrical signals radiated unintentionally from electronic equipment can cause interference to radio and television services. Information Technology Equipment causes interference to all radio broadcast services, particularly those below 200 MHz, including police, aeronautical and broadcast services. The process by which electromagnetic interference is radiated from Information Technology Equipment is, however, not fully appreciated. The mechanism of radiated of electromagnetic interference from Information Technology Equipment is described and models are proposed to facilitate understanding of the phenomenon.
SOME RECENT ADVANCES IN THE THEORY OF TIKHONOV
REGULARIZATION: PART II
This is the continuation of the discussion started in Musa (2001) on the recent developments in the concept of Tikhonov regularization of linear illposed operator equations. In Musa (2001) we treated the ordinary and iterated Tikhonov regulation and convergence rates and saturation phenomena for both cases. There we also highlighted the virtues of the iterated Tikhonov regularization. Part II covers (a) Tikhonov regularization involving linear differential operator (b) constrained Tikhonov regularization. We seek in each case a unified theory for various approaches to Tikhonov regularization and an understanding of the properties of the regularized solution. It is shown in this paper that under appropriate choices of the topologies of the Hilbert spaces on which the operators act, regularization with differential operators is a special case of the abstract theory of Tikhonov regularization; the abstract theory appear in Part I. In the context of constrained regularization, Part II additionally demonstrate the notion of “metric projection of unconstrained Tikhonov solution”. This latter concept is cheaper numerically than the direct constrained Tikhonov regularization in which regularization is achieved simultaneously with the imposition of the constraints.