African
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Journal of Applied Science and
Technology
(JAST)
Journal of Applied Science and Technology (JAST), Vol. 5, Nos. 1 & 2, 2000, pp. 1 - 13
ON THE TREATMENT OF RESONANCE CROSS SECTIONS IN THERMAL REACTOR LATTICES USING THE WIMSD/4 TRANSPORT LATTICE CODE
S. Anim-Sampong, E.H. K. Akaho & J.K. Gbadago
Dept. of Nuclear Engineering & Material Science, National Nuclear Research Institute, Ghana Atomic Energy Commission, P.O. Box LG 80, Legon, Accra. Ghana.
ABSTRACT
This paper discusses the mathematical models and methods used for calculating resonance cross sections in the resonance region of the neutron energy spectrum. Particular attention has been paid to the treatment outlined in the WIMSD/4 version of the WIMS lattice transport code. The significance of the resonance integral evaluation needed for computing the effective group resonance cross sections is also presented. The resonance treatment was applied to the Ghana Research Reactor-1 fuel lattice to compute the resonance escape probability, Dancoff factors, flux depression factors corrected for resonance absorption to the removal cross sections and the evaluated correct-ion factors in the 13 resonance energy groups of the WIMSD/4 lattice code. The application shows that the resonances for the n*fission (or Nu*Fission) cross sections are higher than for absorption cross-sections with the resonance energy spectrum for resonance absorbers U235 and Pu239. The Dancoff factor increased by a nominal 0.9 % across the resonance energy range.
Journal of Applied Science and Technology (JAST), Vol. 5, Nos. 1 & 2, 2000, pp. 14 - 24
CALCULATION OF MULTIGROUP REACTION RATES FOR THE GHANA RESEARCH REACTOR-1 FUEL LATTICE CELL USING THE WIMSD/4 TRANSPORT LATTICE CODES
S. Anim-Sampong, E.H.K. Akaho and J.K. Gbadago
Dept. of Nuclear Engineering & Materials Science, National Nuclear Research Institute, Ghana Atomic Energy Commission, P.O. Box LG 80, Legon, Accra, Ghana.
ABSTRACT
A 4-energy multigroup calculation of neutron reaction rates for absorption, fission,n*fission nuclear reactions have been performed at room temperature (293 K) for six resonance absorbers or isotopes: U234, U235, U238, Pu239, Pu240 and Pu241 of a five-region fuel lattice cell of the Ghana Research Reactor-1 using the WIMSD/4 transport lattice code. The corresponding number of nuclear reactions occurring in the fuel material of the lattice cell was also computed for the U235 fissile resonance absorber. The discrete ordinate spatial model, which pro-vides solution to the differential form of the transport equation by the Carlson-SN (N=4) approach was adopted to solve the Ludwig-Boltzmann multigroup neutron transport equation for this analysis. The results show that for any fissile resonance absorber, the reaction rates increased from the fast energy group, followed by thermal group 1 (higher end of thermal energy range), the resonance energy, and peaking for thermal group 2 (lower end of the thermal range). On the contrary, the absorption reaction rates were highest in the resonance energy range for the fertile absorbers.
Journal of Applied Science and Technology (JAST), Vol. 5, Nos. 1 & 2, 2000, pp. 25 - 31
COMPARISON FOR SOME MEASURED AND CALCULATED NUCLEAR PARAMETERS FOR GHANA RESEARCH REACTOR-1 CORE
E.H.K. Akaho, B. T. Maakuu & M.K. Qazi†
Department of Nuclear Engineering & Material Science, National Nuclear Research Institute,
Ghana Atomic Energy Commission, P.O. Box LG80, Legon-Accra, Ghana.
† Institute for Nuclear Power, Pakistan Atomic Enery Commission, P.O. Box 3140, Islamabad, Pakistan.
ABSTRACT
A 30 kW tank-in pool reactor, Ghana Research Reactor-1 (GHARR-1), installed at the National Nuclear Research Institute, Kwabenya, went critical on December 17, 1994. GHARR-1 is an inherently safe reactor employing Highly Enriched Uranium (HEU) as fuel, light water as moderator and beryllium as reflector. Reactor physics calculations of GHARR-1 core have been performed to determine its different design parameters. The lattice code Winfrith Improved Multigroup Scheme (WIMS) was used to generate group constants for four energy groups and the diffusion code CITATION was used for a three-dimensional core calculations in order to compute neutron fluxes associated with various regions of the core. The computed thermal neutron flux levels in the radial and axial direct-ions for different zones of the reactor compared favourably with measured values obtained from the zero power critical experiments. The trends of fast, slowing down, epithermal and thermal fluxes were also predicted.
Journal of Applied Science and Technology (JAST), Vol. 5, Nos. 1 & 2, 2000, pp. 32 - 38
NUCLEAR SAFETY-RELATED CALCULATIONS FOR GHANA RESEARCH REACTOR-1 CORE
E. H.K. Akaho & B. T. Maakuu
Department of Nuclear Engineering & Material Science, National Nuclear Research Institute,
Ghana Atomic Energy Commission, P.O. Box LG80, Legon-Accra, Ghana.
ABSTRACT
Safety-related calculations were performed using lattice code Winfrith Improved Multigroup Scheme (WIMS) and diffusion code CITATION for Ghana Research Reactor-1 (GHARR-1) core with high-enriched uranium (HEU) fuel elements. Results are provided for power peaking factors with partially inserted control rods, kinet-ic parameters and isothermal reactivity coefficients. Comparisons of some computed values with results obtain-ed using other codes, which are in good agreement, are presented.
Journal of Applied Science and Technology (JAST), Vol. 5, Nos. 1 & 2, 2000, pp. 39 - 44
SHIELDING CALCULATIONS FOR CHANGING FROM CIRCULAR TO A
RECTANGULAR SOURCE CONFIGURATION FOR A PILOT SCALE IRRADIATOR
J.J. Fletcher, G. Emi-Reynolds & E.T. Glover
Ghana Atomic Energy Commission, P.O. Box LG80, Legon-Accra, Ghana.
ABSTRACT
The Radiation Technology Centre (RTC) of the Ghana Atomic Energy Commission operates a 1.85 PBq Co-60 gamma irradiator for research, food preservation and medical sterilization. It has become necessary to improve the do-se rate delivered by changing the circular arrangement of sources to a rectangular one. The irradiator needs upgrading from 1.85 PBq to 18.5 PBq for cost effective operations. Since funding is not readily available, changing the geometry of the source is an option being considered. The elliptical and line source approximations methods for calculating the dose rate for the proposed rectangular Co-60 source are described and used to ascertain whether additional shielding will be required or not. The initial dose rate at 1.0 m from the cylindrical source was 368 Svh-1 but the elliptical source method gave 625 Svh-1 whilst the line source method predicted 649 Svh-1; if the source was considered rectangular. From these calculations, the dose rates at the occupied sites ³ 5.0 m, require concrete wall shielding of thickness, t = 183.1 cm as against the 190 cm which is now in place at the RTC. This implies that the biological shi-eld in place is adequate for the replacement of the cylindrical source cage with a rectangular or plaque type.
Journal of Applied Science and Technology (JAST), Vol. 5, Nos. 1 & 2, 2000, pp. 45 - 49
MULTI-ELEMENT ANALYSIS OF UNIDENTIFIED FALLEN OBJECTS
FROM TATALE IN THE NORTHERN REGION OF GHANA.
E.K. Osae., J.J. Fletcher†, Y.Serfor-Armah, B.J.B. Nyarko and F.G. Ofosu
National Nuclear Research Institute, †Radioactive Waste Management Centre,
Ghana Atomic Energy Commission (GAEC), P. O. Box LG80, Legon, Accra, Ghana.
ABSTRACT
A multi-element analysis has been carried out on two fallen objects, # 01 and # 02, using instrumental neutron activation analysis technique. A total of 17 elements were identified in object # 01 while 21 elements were found in object # 02. The two major elements in object # 01 were Fe and Mg, which together constitute about 38 % of the total material concentration of the object. Also 10 out of the 17 elements found for object # 01 have concentrations within the meteorites range while only 3 elements fell in the range for rocks. For object # 02 the major elements were four and these constitute about 27.8 % of the mass of the object. Also of the 21 elements found in object # 02 only 3 of them had concentrations within the meteorite range while 8 elements were in the range for rocks. Therefore, object # 01 could be a meteorite while object # 02 is more of an earthly origin.
Journal of Applied Science and Technology (JAST), Vol. 5, Nos. 1 & 2, 2000, pp. 50 - 55
TISSUE BANKING: CURRENT PROCEDURES, ETHICAL CONSIDERATIONS AND POTENTIAL APPLICATIONS IN THE HEALTHCARE SYSTEM IN GHANA
A. Adu-Gyamfi
Department of Food Science & Radiation Processing,
Biotechnology & Nuclear Agriculture Research Institute (BNARI),
Ghana Atomic Energy Commission (GAEC), P. O. Box LG.80, Legon, Accra, Ghana.
ABSTRACT
Tissue banking provides safe and effective cells and tissues for transplantation in reconstruction surgery. Bone, amnion, skin, cartilage, heart valves and xenograft tissues are the most commonly used biological tissues. Acquisition of tissue is dependent on elaborate donor screening criteria based on medical and social history, physical examination, serology and microbiology. Processing of tissues involves washing, freeze-drying, cryo-preservation, pasteurisation, packaging and radiation sterilisation. Social, religious and ethical issues rather than medico-technical problems play major role in the acceptance of the practice by diverse societies. It is recommended that there should be a collaboration among the Gamma Irradiation Facility at the Ghana Atomic Energy Commission, the Reconstruction and Plastic Surgery Units and the Orthopaedic Departments of the major national hospit-als in establishing a tissue bank in Ghana.
Journal of Applied Science and Technology (JAST), Vol. 5, Nos. 1 & 2, 2000, pp. 56 - 62
OPTIMIZATION OF MUTANT RECOVERY FROM PLANTS OBTAINED FROM GAMMA-RADIATED SEEDS OF WINGED BEAN (Psophocarpus tetragonolobus (L) DC)
G.Y.P. Klu and A.M. van Harten†
Biotechnology & Nuclear Agriculture Research Institute, Ghana Atomic Energy Commission, (GAEC), P. O. Box AE 50, Atomic Energy, Accra, Ghana.
†Department of Plant Breeding, Wageningen Agricultural University, Lawickse Allee 166,
P. O. Box 386, 6700 AJ. Wageningen, The Netherlands.
ABSTRACT
Dry seeds of winged bean (Psophocarpus tetragonolobus (L.) DC) cvs UPS 122 and Kade 6/16 were treated with acute radiation doses of 150 Gy and 250 Gy at a dose rate of 737.32 Gy/hr from a Cobalt-60 gamma source for studies in optimisation of mutant selection in M2 and M3 populations. Mature dry pods were harvested at four different locations on each M1 plant viz. 0.5, 1.0, 1.5 and 2.0 metres from the ground. M2 seedlings we-re screened for different groups of chlorophyll deficiencies and their frequencies. Reduction in chlorophyll mutation frequency from the first formed seeds to the latest ones within the M1 pods has been observed for both cultivars studied. The high degree of chimerism recorded in the M2 seedlings present in the first-formed seeds in the M1 pods provides a clear indication that these seeds constitute a zone from which seeds for the M2 generation have to be harvested in order to give the highest probability for obtaining different types of mutants. On the other hand, significant differences in mutation frequency were not obtained in M2 seedlings from pods harvested at the various positions on the M1 plants. M1 pods can be harvested at any height on the M1 plant, but it is preferable to use the earliest mature ones to save time and labour. The zones identified on M1 plants in this investigation coupled with the use of the "spare" or "remnant" seed selection method, should provide an improved method for mutation breeding in a viny legume like the winged bean.
Journal of Applied Science and Technology (JAST), Vol. 5, Nos. 1 & 2, 2000, pp. 63 - 69
EFFECTS OF CHEMICAL SENSITIZERS ON GAMMA RADIATION PROCESSING OF NATURAL RUBBER LATEX PRODUCED IN GHANA
S. A. Dogbe,
Department of Chemistry, National Nuclear Research Institute,
Ghana Atomic Energy Commission (GAEC), P. O. Box LG 80, Legon, Accra, Ghana.
ABSTRACT
The potential of gamma radiation processing in cross-linking natural rubber latex (NRL) for production of dipped goods has been studied. NRL produced in Ghana was irradiated to 10, 20, 30, 40 and 50 kGy, respectively, in a Gamma Chamber of dose rate 0.65 kGy/h. Irradiation of the NRL was also carried out in the presence of chemical sensitizers, namely, tetrachloromethane (CCl4), 2-ethylhexyl acrylate (2-EHA) and n-butyl ac-rylate (n-BA), respectively, to observe their effect on the efficiency of gamma radiation processing. The degree of cross-linking by gamma radiation alone, and in combination with the sensitizers were determined by measurement of tensile strength, elongation at break, swell and gel formation of films prepared from irradiated NRL. The highest cross-linking of the NRL was achieved at comparatively low dose of 20 kGy in the presence of n-BA. Radiation processing of NRL in the presence of n-BA, as observed in this study, promises to be effective method for cross-linking NRL produced in Ghana.
Journal of Applied Science and Technology (JAST), Vol. 5, Nos. 1 & 2, 2000, pp. 70 - 76
TIME AND TEMPERATURE EFFECTS IN CREEP AND CREEP RECOVERY OF POLYMETHYL-METHACRYLATE (PMMA)
A. Ayensu
Industry, Natural and Social Sciences Sector, CSIR, P.O. Box M32, Accra, Ghana.
ABSTRACT
Experiments were conducted to investigate the torsional creep and creep recovery processes in polymethyl-methacrylate (PMMA or Perspex) in the temperature range from 228 K to 296 K. The relaxation process was described by shear compliance equation of the form, J(t) = 3.61 x 10-9 X(t) N-1m2, where X(t) is the torsional deflection at time t. The theory of the relaxation was analysed to obtain the shift factor (log10aT) required for plotting the master curve. The logarithmic plots of shear compliance-time curves were superimposed to form one smooth curve by shifting the individual curves along the time axis. The shift values measured for the test temperatures were used to determine the mean value of the activation energy as 39.5 kJ/mole. The results of the experiments also confirmed that Boltzmann's superposition principle holds within the temperature range investigated.
Journal of Applied Science and Technology (JAST), Vol. 5, Nos. 1 & 2, 2000, pp. 77 - 86
GROUNDWATER AS SOURCE OF RURAL WATER SUPPLY IN GHANA
P. Gyau-Boakye & S. Dapaah-Siakwan
Council for Scientific and Industrial Research - Water Research Institute (CSIR - WRI),
P.O. Box M 32, Accra, Ghana.
ABSTRACT
The exploitation of groundwater for water supply needs of many rural communities in Africa has been on the increase in the last decade. The emphasis or reliance on groundwater supplies for rural communities stems from the fact that groundwater sourcing is not only feasible but also the most economic source of potable water. The groundwater potential of the various geologic formations in Ghana and the water quality have been assessed to meet the rural water supply needs.
Journal of Applied Science & Technology (JAST), Vol.5, Nos. 1 & 2, 2000, pp. 87 - 97
UTILIZATION OF AVAILABLE WATER RESOURCES IN THE NORTHERN PART OF THE VOLTA REGION OF GHANA
K. Kankam-Yeboah & S. Opoku-Duah
Council for Scientific and Industrial Research, Water Research Institute (CSIR-WRI),
P. O. Box M.32, Accra, Ghana. e-mail: [email protected]
ABSTRACT
A study on water supply systems in the Northern Volta Region was conducted between 1993 and 1996. The results indicated that about 2.6 % of all water delivery systems in the study area occur as pipe-borne water, 26.5 % are boreholes, 25.4 % and 11 % are hand-dug wells and dugouts, respectively. The remaining 34.5 % of water delivery system are available in raw forms as rivers, streams, springs and natural ponds. The study further revealed that water supply coverage in the area has slightly improved between the period 1990 and 1996 from lower than 40 to 44 % and 58 to 73 % in the rural and urban centres, respectively. While the general physico-chemical quality (e.g. ECw = 53 - 826 mS cm-1) of both surface and groundwater sources was considered good for domes-tic supply the results of bacteriological analysis showed extremely high levels of faecal and coliform counts, likely to cause health hazards.
Journal of Applied Science and Technology (JAST), Vol. 5, Nos. 1 & 2, 2000, pp. 98 - 107
THERMAL REMOTE SENSING DATA FOR ESTIMATING EVAPOTRANSPIRATION ON A REGIONAL SCALE
(A CONCEPTUAL APPROACH)
S. Opoku-Duah, K. Kankam-Yeboah & S. Adu-Prah†
Council for Scientific & Industrial Research, Water Research Institute (CSIR-WRI),
P.O. Box M 32, Accra, Ghana. e-mail: [email protected]
† Remote Sensing Applications Unit, Dept. of Geography & Resource Development, University of Ghana, Legon, Ghana. e-mail:
[email protected]
ABSTRACT
The amount of evapotranspiration (ET) is an essential input for modelling the water balance equation, and also has substantial value in the overall estimation of available water for long-term planning of the water resources of regional or very large river basins, such as the Nile, Congo, Niger and Volta. As an alternative to in-situ hydro -physical measurements, theoretical and computer-based models, a method that applies thermal infrared band (6) of Landsat TM data for the estimation of ET on a basin-wide scale is presented.
Journal of Applied Science and Technology (JAST), Vol. 5, Nos. 1 & 2, 2000, pp. 108 - 113
A SUSPENDED SEDIMENT YIELD PREDICTIVE EQUATION FOR RIVER BASINS IN THE SOUTHWESTERN RIVER BASIN SYSTEM OF GHANA
B. A. Amisigo & S. A. Akrasi
Council for Scientific and Industrial Research - Water Research Institute (CSIR - WRI),
P.O. Box M 32, Accra, Ghana.
ABSTRACT
An empirical equation that can be used for estimating the suspended sediment yields of river drainage basins without sediment data has been established for basins in the sub-tropical forest Southwestern river basin system of Ghana. The power law equation relates mean annual specific suspended sediment yield (t km-2 yr-1) of the drain-age basin to the basin area (km2) and the mean daily stream discharge (m3/s) of the river at the outlet of the draiinage basin. Values of the parameters of the equation were computed from the least squares linear regression fit to the logarithmic transforms of observed mean annual specific suspended sediment yield, mean daily stream discharge and basin area data at selected river gauging stations in the basin system. The equation was found to fit the observed data very well with a high coefficient of multiple determination, R2 of 0.95. The fit was found to be better than those relating mean annual specific suspended sediment yield to basin area or runoff only. Since many stream gauging stations in the country have no records on fluvial sediment, the empirical equation can be used to obtain preliminary estimates of expected sediment load of streams for engineering design of hydraulic structures such as reservoirs.
Journal of Applied Science and Technology (JAST), Vol. 5, Nos. 1 & 2, 2000, pp. 114-123
STATUS OF GENETIC RESOURCES OF TROPICAL AND SUB-TROPICAL FRUITS IN GHANA
S. O. Bennett-Lartey and C. M. Asare
Council for Scientific & Industrial Research, Plant Genetic Resources Centre (CSIR-PGRC), P.O. Box 7, Bunso, Ghana.
ABSTRACT
In Ghana, there are a lot of indigenous fruit species and their relatives, which have not yet been exploited. A major component of successful breeding programme is the collection and conservation of germplasm with the view to exploiting the variation that may exist in the populations. Efforts have been made since the era of colonization to introduce, conserve and utilize various fruit species. Problems such as losses through diseases and other environmental hazards including bush fires and drought have been associated with the conservation of fruit species germplasm in the field. This paper reports on some of the indigenous and introduced fruit species available, efforts that are being made to conserve them in the field, threats to these collections and efforts that are being made to alleviate the dangers posed by these threats.
Journal of Applied Science and Technology (JAST), Vol. 5, Nos. 1 & 2, 2000, pp. 124-128
PROPAGATION OF NUTMEG (Myristica fragrans HOUTT)
C.M. Asare and S.O. Bennett-Lartey
Council for Scientific & Industrial Research, Plant Genetic Resources Centre,
CSIR-PGRC, P. O. Box 7, Bunso, Ghana
ABSTRACT
The mode of propagation of a tree crop is perhaps the most important factor in its successful cultivation. Nut-meg is a dioecious plant which is propagated sexually and asexually, the former being the usual practice. The mode of propagation tends to influence progenies in terms of heredity, plant architecture and the gestation period. This paper describes the methods tested at the Plant Genetic Resources Centre (CSIR-PGRC), Bunso and points out the merits and demerits of the different techniques used in the propagation of nutmeg.
Journal of Applied Science and Technology (JAST), Vol. 5, Nos. 1 & 2, 2000, pp. 129-141
PHOSPHOGLUCOSE ISOMERASE POLYMORPHISM IN CULTIVATED GROUNDNUT (Arachis Hypogaea L.) AND SOME OF ITS WILD RELATIVES IN SECTION Arachis.
R. Akromah.
Council for Scientific & Industrial Research, Plant Genetic Resources Centre (CSIR-PGRC), P. O. Box 7, Bunso, Ghana.
ABSTRACT
Horizontal starch gel electrophoresis was used to study one of the enzymes involved in glycolysis, Phosphoglucose isomerase subunits (PGI) (EC 5.3.1.9), in the cultivated groundnut, Arachis hypogaea, and some of its wild relatives. Two gene loci specifying PGI were detected. The more anodal locus, Pgi-1, was monomorphic in all the species studied. Polymorphism was detected at the locus close to the origin, Pgi-2, in the cultivated ground-nut as well as the wild species, with two distinct alleles present at this locus. The two subspecies of A. hypogaea exhibited different banding patterns. With few exceptions, ssp. hypogaea accessions exhibited homozygosity for the first allele while all accessions of ssp. fastigiata exhibited 'fixed' heterozygosity for the two alleles at the second locus. These differences serve as significant markers for sorting landraces of the cultivated groundnut into subspecies and appear to correlate well with the established morphological differences in the subspecies of A. hypogaea already known to groundnut workers. The probable significance of heterozygosity in cultivar performance is discussed.
Journal of Applied Science and Technology (JAST), Vol. 5, Nos. 1 & 2, 2000, pp. 142-147
QUALITY ASSESSMENT OF FERMENTED CASSAVA DOUGH (AGBELIMA) ON GHANAIAN MARKETS
N.T. Dziedzoave†, W.O. Ellis, I. Oduro. and J.H. Oldham,.
†Council for Scientific and Industrial Research, Food Research Institute, (CSIR-FRI),
P.O. Box M 20, Accra, Ghana
Department of Biochemistry, Kwame Nkrumah University of Science & Technology,
Kumasi, Ghana
ABSTRACT
In order to provide baseline data for developing standards for cassava fermented dough (agbelima) and standardizing the production process, an investigation was conducted to determine the extent of variation in certain quality indices of agbelima from various selected markets. Objective assessment of the chemical, textural and colour indices of tw-enty samples of agbelima purchased from five different markets were carried out. Significant differences in moisture content (p < 0.01), pH (p < 0.01), uniformity index (p < 0.01) and a* (p < 0.05) were observed between samples from different markets. No significant differences were observed with respect to total titratable acidity, starch content, fineness modulus, average particle size and the other colour parameters. Variations between samples from the same markets were very minimal except for the uniformity index which showed wide variations.
Journal of Applied Science & Technology (JAST), Vol.5, Nos. 1 & 2, 2000, pp. 148-155
QUALITY ATTRIBUTES AND UTILIZATION OF CURED FISH IN GHANA
J. Nketsia-Tabiri and S. Sefa-Dedeh†
Department of Food Science & Radiation Processing,
Biotechnology. & Nuclear Agriculture Research Institute, P. O. Box LG. 80, Legon.
†Department of Nutrition & Food Science,
University of Ghana, P. O. Box LG. 134, Legon,
ABSTRACT
Cured fish products were evaluated in terms of chemical composition and sensory quality. The moisture content of the smoked fish products ranged between 11.7 - 69.2 % (db), with salt content of 0.4 - 1.2 %, sodium content of 0.6 - 1.0 %, potassium content of 4.3 - 8.7 %, crude protein of 71.5 - 84.5 % and fat content of 7.2 - 19.0 % (all on dry matter basis). The salted-fermented fish products had moisture content of 48.4 - 58.3 % (db), salt content of 33.0 - 44.2 %, sodium content of 17.7 - 20.3 %, potassium content of 4.7 - 5.2 %, crude protein of 49.0 - 57.7 % and fat content of 2.1 - 3.7 %. Salted dried tilapia had moisture content of 45.8 %, salt content of 21.5 %, sodium content of 8.3 %, potassium content of 4.2 % , crude protein content of 67.2 % and fat content of 7.9 %, respectively. Consumer perceptions and expectations of desirable quality attributes were found to be dependent on the type of cured fish and how it was prepared before consumption. Both consumers and processors considered texture, flavour and colour as important quality attributes in the utilization of cured fish.
Journal of Applied Science and Technology (JAST), Vol. 5, Nos. 1 & 2, 2000, pp. 156-161
EFFECTS OF SALTING AND DRYING CONDITIONS ON THE QUALITY OF SALTED DRIED TILAPIA (Oreochromis niloticus) FISH
J. Nketsia-Tabiri and S. Sefa-Dedeh †
Department of Food Science & Radiation Processing,
Biotechnology & Nuclear Agriculture Research Institute, P. O. Box LG. 80, Legon.
†Department of Nutrition & Food Science, University of Ghana, P. O. Box LG. 134, Legon,
ABSTRACT
The effects of salting time, drying time and drying method on the moisture content, salt content and hardness of salted dried tilapia (Oreochromis niloticus) fish were investigated using a randomized complete block factorial design. Temperatures ranging from 29.0 - 35.5 °C were used for open air sun-drying and temperatures from 34 - 54 °C were used for solar drying. All the three process variables had significant effects (p = 0.05) on the moisture content of the salted dried fish, but the salting time had significant effect (p < 0.1) only on the salt content. Regression analysis of the data yielded models with high coefficients of determination (³ 0.90) for the prediction of the moisture and salt content of solar and open sun-dried salted fish. The solar dried salted fish generally attained lower moisture levels than the open sun-dried samples. Analysis of sensory scores indicated that the hardness of salted dried fish decreased with salting time while increasing with drying time. A significant correlation was found between the hardness and accept-ability of salted dried fish. The conditions for producing the most acceptable salted dried fish were 24 hours salting time and 42 hours open sun-drying; the predicted moisture and salt content of these products were respectively 61.8 % (db) and 21.3 % (db). Hence, processing conditions involving short salting time and long drying time resulted in salted dried fish products with acceptable textural quality.
Journal of Applied Science and Technology (JAST), Vol. 5, Nos. 1 & 2, 2000, pp. 162-167
ASSESSMENT OF TRANSPORT SERVICES IN PERI-URBAN SETTLEMENTS
IN KUMASI
F.K. Afukaar and W.K. Agyemang
Council for Scientific and Industrial Research, Building and Road Research Institute
(CSIR-BRRI), Traffic and Transportation Engineering Division,
P.O. Box 40, KNUST, Kumasi, Ghana.
ABSTRACT
This study was undertaken to ascertain the transport and travel patterns of peri-urban settlements in Kumasi, by assessing the modal choices and trip characteristics of the peri-urban residents in meeting socio-economic needs. The 'trotro' (mini-bus) and walk modes were the two most dominant forms of transportation, accounting for about 90 % of the trips made. Walking was most common for trips to schools and social purposes, whilst the 'trotro' (mini-bus) was an important mode of transport to the market, hospital and workplace. About 60 % of all trips were less than 6.0 km in length and just about 20 % were longer than 10 km. The commutation to the city was common because, the peri-urban residents depended more on the city than their locality for health and market (shopping) needs.
Journal of Applied Science and Technology (JAST), Vol. 5, Nos. 1 & 2, 2000, pp. 168- 176
A RATIONAL PROCEDURE FOR THE SELECTION OF APPROPRIATE PROCUREMENT SYSTEMS FOR CONSTRUCTION WORKS IN GHANA
E. Osei-Tutu and T. Adjei-Kumi†
Council for Scientific & Industrial Research, Building & Road Research Insitute,
CSIR-BRRI, P.O. Box 40, KNUST Post Office, Kumasi
† Department of Building Technology, KNUST, Kumasi.
ABSTRACT
Construction work is procured via a number of systems, such as being Open and Competitive, Selective, and Negotiated tendering systems. The choice of the most appropriate system for a particular project is dependent on the client, level of risk, time availability, etc. The basis for the selection of such systems has been branded experience-based, which is tied to an individual and not available to the wider industry for consideration, validation, documentation and acceptance. In this paper, a rational procedure has been developed that facilitates the selection of procurement routes for construction projects as a means to enhance the quality of management decisions on projects. A brief review is given of the mode of selection of construction procurement systems and identifies the key factors affecting the choice of such systems in Ghana. The development of a weightage system for these factors based on which a novel approach to construction procurement decision-making is pro-posed is also highlighted. A computer-based model for this approach is presently being implemented within a prototype system to demonstrate the potential of integrated knowledge-based systems to decision-making procedures in the construction industry.
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