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Estimation Of Volatile Cloud Density For Single Coal Particles Using Microgravity Condition, H. Katalambula Dec 1999

Estimation Of Volatile Cloud Density For Single Coal Particles Using Microgravity Condition, H. Katalambula

Tanzania Journal of Engineering and Technology (TJET)

Single coal particle’s volatile cloud density has been estimated by employing a microgravity condition. The volatile yield was found to decrease with pressure while the density was found to increase, indicating that volatiles occupies less space when under pressure and hence causing some volatiles to be retained within the particle. The volatile cloud density was also found to increase with volatile yield suggesting volatile composition changes with yield. The effect of heating rate on volatile yield was found to be the same as reported by other investigators where the yield increased with heating rate.

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Concrete Cracking In Coastal Areas, S. R. Mpinzire Dec 1999

Concrete Cracking In Coastal Areas, S. R. Mpinzire

Tanzania Journal of Engineering and Technology (TJET)

The paper discusses cracking and corrosion of reinforced concrete (RC) structures in coastal zones where aggressive action of salt burdened air is the primary cause of concrete deterioration. Case studies are presented, along with discussion of possible remedies including local demolition, reconstruction and epoxy injection as well as concrete treatment.

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The Development Of Groundwater For Water Supply, C. F. Mhilu Dec 1999

The Development Of Groundwater For Water Supply, C. F. Mhilu

Tanzania Journal of Engineering and Technology (TJET)

ABSTRACT This paper presents results of groundwater investigations carried out at Yombo Dovya Village, Temeke District in Dar es Salaam Region. The study has included hydrogeological and geoelectric resistivity sounding survey data obtained at the test site in Yombo village. The results of this investigation based on the application of vertical electrical sounding probe predictions have indicated the existence of reasonable amounts of groundwater resource for development. To verify these results borehole drilling tests were also conducted at the same site (Borehole No. DSM 79/99), and the results obtained by this method compares very well with those obtained earlier by …

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Macrominerals In The Milk Of Healthy And Mastitic Cows, I E. Mohamed, O A. Olowni, F I. Habbani, G E. Mohamed Dec 1999

Macrominerals In The Milk Of Healthy And Mastitic Cows, I E. Mohamed, O A. Olowni, F I. Habbani, G E. Mohamed

Tanzania Journal of Science

Concentration values were obtained using X-ray fluorescence (XRF) technique for chlorine, potassium and calcium levels in milk-from subclinical and clinical mastitis-infected COWS. Concentration values for sodium were determined using atomic absorption spectroscopy. Comparisons were made with healthy cow's milk. Subclinical mastitic milk had significantly higher levels of sodium and chlorine and significantly lower levels of potassium and calcium than the milk from healthy cows. Comparison between clinical mastitic milk revealed a significant increase in sodium and chlorine levels for clinical mastitic milk, while levels of potassium showed a non-significant change and calcium levels decreased significantly.

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Tidally Induced Flow In Chwaka Bay Zanzibar, O U. Mwaipopo Dec 1999

Tidally Induced Flow In Chwaka Bay Zanzibar, O U. Mwaipopo

Tanzania Journal of Science

Time series data of currents and sea current levels recorded by current meter and tide gauges, respectively from Chwaka Bay, Zanzibar were obtained from the entrance near to Mapopwe Creek and at the middle of the bay. The analysis of the data reveals that the tidal currents had an asymmetry near the entrance to Mapopwe Creek where the ebb currents were stronger than flood currents although the ebb periods were considerably longer than flood periods.

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Stable Isotope Compositions Of Sedimentary Organic Matter Off Zanzibar Town, Ann Muzuka Dec 1999

Stable Isotope Compositions Of Sedimentary Organic Matter Off Zanzibar Town, Ann Muzuka

Tanzania Journal of Science

Stable isotope compositions of sedimentary organic carbon for sediments collected off the Zanzibar Town averaged -17.9%. Low isotope values of organic carbon, which were associated with high C/N ratios, were observed within Zanzibar harbour suggesting a significant contribution of terrestrial organic matter to the harbour. Sediments collected outside the Zanzibar harbour were richer in 13C than those collected within the harbour area. This 13 enrichment in 13C can be attributed to a decrease in the influence of terrestrial organic matter (0M) and high contribution of' sea grasses. A decrease in the influence of terrestrial OM is further supported …

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A Simple Method For Indexing Powder Diffraction Patterns Of Cubic Materials (11): Using The D-Values Of Reference, Me Kamwaya Dec 1999

A Simple Method For Indexing Powder Diffraction Patterns Of Cubic Materials (11): Using The D-Values Of Reference, Me Kamwaya

Tanzania Journal of Science

From the d-values (in decreasing order) taken from powder diffraction patterns of the cubic material a variable constant, KQ, which is a multiple of Ʃh12 where Q = l/d2 can be determined. The smallest values of Q give rise to multiples of ones, twos and threes, which correspond to the smallest values of Ʃh12 for the primitive, bcc, and fcc/diamond Type structures, respectively. Cognance of the lattice types is best accomplished by the ΔQ-criterion, where ΔQ denotes the difference between successive values of Q. Indexing is greatly simplified and the use of rigorous tables is …

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Bis(4-Carboxylato-5-Methyl-Oxazolidine) Nickel(Ii)Dihydrate, Its Preparation And Crystal Structure, Me Kamwaya Dec 1999

Bis(4-Carboxylato-5-Methyl-Oxazolidine) Nickel(Ii)Dihydrate, Its Preparation And Crystal Structure, Me Kamwaya

Tanzania Journal of Science

An aqueous solution of nickel (Il) acetate tetrahydrate was added to warm solution of L-threonine and sodium bicarbonate. The mixture was subsequently treated with aqueous solution of formaldehyde and stirred until the blue solution turned green. The reaction consists in a base catalysed condensation of formaldehyde with L-threonine-nickel (Il) – complex followed by formation of an oxazolidine ring. A single crystal X-ray investigation was carried out at 120(1) oC. The X-ray structure analysis showed an octahedral nickel comp/ex containing two water molecules. The oxazolidine rings were connected to the Ni by nitrogen and one of the carboxylato oxygen atoms. …

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Heavy Metal Content In Water Hyacinth (Eichhornia Crassipes (Mart) Solms.) From Lake Victoria Shore, Tanzania, Nk Mohammed, In Makundi Dec 1999

Heavy Metal Content In Water Hyacinth (Eichhornia Crassipes (Mart) Solms.) From Lake Victoria Shore, Tanzania, Nk Mohammed, In Makundi

Tanzania Journal of Science

Water hyacinth (Eichhornia crassipes (Mart) Solms,) samples from Lake Victoria shore were analysed for heavy metal pollution using Energy Dispersive X-ray Fluorescence Spectroscopy (EDXRF). The roots of the water hyacinth samples were collected from areas influenced by industrial and domestic sewage and little influenced area. Water hyacinth from industrial area and those from sewage discharge points had higher concentrations of heavy metals than that from the little disturbed area.

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Comparison Of Synchronization Strategies For Systems Employing Multiple-Code Markers, Hn Kundaeli Dec 1999

Comparison Of Synchronization Strategies For Systems Employing Multiple-Code Markers, Hn Kundaeli

Tanzania Journal of Science

Frame synchronization strategies based on single-code markers have been widely researched and reported. On the other hand, frame synchronization strategies based on multiple-code markers have not been so well reported although they have become quite popular in systems operating at high transmission rates. In this paper, the performance of various synchronization strategies for systems employing multiple-code markers is compared. It is shown that, systems employing contiguous multiple-code markers have better performance than those employing distributed multiple-code markers. It is also shown that, systems in which the individual codewords of the markers are checked during loss of synchronization hare better performance …

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Facies Analysis Of Limestones At Songo Songo Island In South East Tanzania, S Kapilima, Ka Msindai Dec 1999

Facies Analysis Of Limestones At Songo Songo Island In South East Tanzania, S Kapilima, Ka Msindai

Tanzania Journal of Science

Songo Songo Island is situated at close proximity of the continental slope of the coastal sedimentary basin of Tanzania. Its rich varieties of marine organisms and carbonate sediments provide a classic example of island emergence with the development of successive detrital and organic reefs as well as lime sand. Facies analysis at the Island was done through mapping, logging, faces and microfacies analysis. Results show that Songo Songo Island can be classified into three faces; the detrital reefs, organic reef and lime sand. The fossil assemblage reveals that most of the fauna and flora are frame-building organisms in organic reef. …

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Turbulent Heat Energy Exchange In A Tropical Bay, S B. Mahongo Dec 1999

Turbulent Heat Energy Exchange In A Tropical Bay, S B. Mahongo

Tanzania Journal of Science

Atmospheric and Sea surface temperature data were used to describe the magnitude of turbulent heat energy processes Chwaka Bay, Zanzibar, Bulk aerodynamic formulae were applied in the investigation for data collected over a 23-day period in 1996. These were those Smith (1988), Friehe and Schmitt (1976), Mohanty and Mohan Kumar (1990) and Bunker (1976). The computed fluxes of moisture were 156 Wm-2 (Smith), 158 Wm-2 (Friehe and Schmitt), 160 Wm-2 (Mohanty and Mohan Kumar) and 188 Wm-2 (Bunker), respectively. The corresponding fluxes of sensible heat were 15 Wm-2, 13 Wm-2, 18 Wm …

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Status Of Heavy Metals Pollution In The Nile Around Khartoum Area, F I. Habbani, S E. Salih Dec 1999

Status Of Heavy Metals Pollution In The Nile Around Khartoum Area, F I. Habbani, S E. Salih

Tanzania Journal of Science

Investigations for heavy metals pollution in the Nile around Khartoum area were carried Out using the technique of x-ray fluorescence (XRF). Samples were collected from various locations around Khartoum area before and after the flood. The results indicated that there was no heavy metals pollution in the Nile in Khartoum area resulting from industrial activities. The origin for the observed heavy metals concentrations, except for Pb, was considered to be soil erosion caused by the river on its journey from the Ethiopian Highlands and Lake Victoria. However, there are indications that some Pb pollution could be due to emissions of …

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Synthesis Of Bis-(3-Carbethoxy-6-Methoxy-4-Methyl-2-Quinolyl) Selenide, Rr Malisa, G L. Mhehe, Sjm Mdachi Dec 1999

Synthesis Of Bis-(3-Carbethoxy-6-Methoxy-4-Methyl-2-Quinolyl) Selenide, Rr Malisa, G L. Mhehe, Sjm Mdachi

Tanzania Journal of Science

In the execution of a synthetic strategy aiming at 3-acetyl-2,4-dichloro-6-methoxyquinoline, a precursor to a 4-methoyselenolo[2,3-b]quinolone, we have instead obtained 2-chloro-3-carbethoxy-6-methoxy-4-methylquinoline. These results strongly suggest that the compound claimed to be 3-acetyl-2,4-dihydroxy-6-methoxyquinoline in the literature and a precursor to 3-actyl-2,4-dichloro-6-methoxyquinoline, is 3-carbethoxy-2-hydroxy-6-methoxy-4-methylquinoline, a precursor to 2-chlo-3-carbethoy-6-methoxy-4-methylquinoline. The reaction of the latter compound with sodium hydrogen selenide in ethanol yielded bis-(3-carbethoxy-6-methoxy-4-methyl-2-quinolyl) selenide.

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Estimating The Usle - Soil Erodibility Factor In Developing Tropical Countries:A Case Study In Tanzania, Metthew Mulengeral Dec 1998

Estimating The Usle - Soil Erodibility Factor In Developing Tropical Countries:A Case Study In Tanzania, Metthew Mulengeral

Tanzania Journal of Engineering and Technology (TJET)

Developing countries in the tropics are facing more soil erosion problems than the developed temperate countries. These developing countries have no accurate locally applicable equation(s) for predicting soil erosion or for planning and implementation of soil conservation measures. Furthermore, These countries do not have the necessary resources to develop the soil loss prediction equation(s). Existing empirical equations like the Universal Soil Loss Equation (USLE) if modified to suit tropical conditions can be useful a tool in soil erosion control in the region for a foreseeable future. In this paper equations'for estimating the soil erodibility factor in the USLE for tropical …

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Oxygen Transfer In A Three-Phase Fluidised Bed Bioreactor With Novel Biomass Support When Used In Industrial Wastewater Treatment, S Manyele, Dec 1998

Oxygen Transfer In A Three-Phase Fluidised Bed Bioreactor With Novel Biomass Support When Used In Industrial Wastewater Treatment, S Manyele,

Tanzania Journal of Engineering and Technology (TJET)

The effect of support mass and liquid height on the oxygen transfer in the three- phase fluidised bed were experi/nenta/ly investigated. Novel biomass support, rhe KMT*, with density of 850 kg/n/ and an equivalent size, dp 8.3 mm, has been used in this work. The oxygen transfer rate was expressed in terms of rhe volumetric oxygen transfer coefficient, kca. It has been found out that the* a values increased with increasing support mass up to a critical solids load of 4.0 kg, above which the kca decreased and that kca decreased with increasing liquid height. It has been recommended that …

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A Comparison Of Three Numerical Methods Of Solutions Of Equations Describing Unsteady Gas Flow At Pipe Boundaries In Reciprocating Compressor Systems, M Mkumbwa Dec 1998

A Comparison Of Three Numerical Methods Of Solutions Of Equations Describing Unsteady Gas Flow At Pipe Boundaries In Reciprocating Compressor Systems, M Mkumbwa

Tanzania Journal of Engineering and Technology (TJET)

A number of finite difference schemes are available to study pressure fluctuation effects in unsteady pipe flows. This paper presents a comparison Of the predictions made by three such schemes of unsteadyjlow effects in a number of reciprocating compressor pipe-work systems. The finite difference schemes considered were;- a first order scheme known as the method Of characteristics, two second order schemes which were the Leapfrog method and MacCormacVs method. A reciprocating compressor simulation computer program was coupled with equations describing the cylinder thermodynamic processes with the pipe flow equations for steady non-homentropicflow. The comparison presented takes into account both the …

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Turbulent Burning Model For Premixed Gaseous Mixtures, E Mushi Dec 1998

Turbulent Burning Model For Premixed Gaseous Mixtures, E Mushi

Tanzania Journal of Engineering and Technology (TJET)

A turbulent burning model for premixed gaseous mixtures has been successfully developed. The model assumes instant burning of vortex Tubes of the order of Kolmogorov scale followed by burning of larger eddies of the order of Taylor micro scale. These eddies burn ar a rate dependent On the stretch rate. The influence of turbulence on the burning rate is introduced in the form of probability density function which gives the probability that a given mixture under turbulence will undergo burning rather than being quenched. The model has been validated againsi experiments involving turbulent explosions in a fan stirred bomb. Model …

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New Technologies For Thermal Disposal Of Sewage Sludge, T Ogada Dec 1998

New Technologies For Thermal Disposal Of Sewage Sludge, T Ogada

Tanzania Journal of Engineering and Technology (TJET)

The traditional methods for the disposal of sewage sludge are landfilling, recycling as fertilisers in agricultural lands, dumping into sea and incineration. In thc recent past, Sludge incineration has been rapidly gaining ground duc to environmental constraints facing the Other methods. However, the cost of pollution control during sewage sludge incineration is currently very high due to the expensive flue gas treatment facility required. Futhermore, large quantity Of ash is produced which is highly contaminated with heavy metals and must be disposed off in special landfilling sites in order to avoid ground water pollution. To reduce the cost Of pollution …

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Experimental Study Of Domestic Charcoal Stoves, Simbo Kimario Dec 1998

Experimental Study Of Domestic Charcoal Stoves, Simbo Kimario

Tanzania Journal of Engineering and Technology (TJET)

The demand of fuelwood for domestic cooking especially the charcoal fuel is increasing in the urban settlements due to the increase in population of low income class earners who are the main consumers Of this type of fuel. This paper is presenting rhe results Of experiments conducted on the popularly used domestic charcoal stoves in Tanzania. The results revealed some significant differences on stoves performances. The type of insulation materials and some design features incorporated into the combustion chambers of the stoves had positive impacts in relative charcoal fuel saving. About two tons of charcoal fuel could be saved by …

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Technical And Economic Comparison Of Performance Between Farmer And Government Managed Irrigation Schemes In Tanzania: A Case Study Of Kapunga Irrigation Project, D Chemka Dec 1998

Technical And Economic Comparison Of Performance Between Farmer And Government Managed Irrigation Schemes In Tanzania: A Case Study Of Kapunga Irrigation Project, D Chemka

Tanzania Journal of Engineering and Technology (TJET)

This paper conwares the perforinance Of governnyent ro fanner-managed irrigation schemes at Kapunga Rice Project in Mbeya Region, south-west Tanzania. The results showed that the farmer-managed irrigation scheme (FMIS) performed better than the government-managed irrigation scheme (GMIS) in attaining good performance. Applicable indicators for farmer-managed irrigation scheme are as shown below with those of government-managed scheme indicated in brackets. Its overall irrigation efficiency was 61' percent (29 percent) average productivity was 3.2 ton/liG (2.2 ton/ha); economic profirability: internal rate of return was 3.2 percent (5 percent), benefit/cost ratio of 0.60 (0.14); while its financial profitability: internal rate of return was …

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The Significance And Effects Of Oil Injection On The Performance Of Sliding Vane Compressors., M Mkumbwa Dec 1998

The Significance And Effects Of Oil Injection On The Performance Of Sliding Vane Compressors., M Mkumbwa

Tanzania Journal of Engineering and Technology (TJET)

A computer model of a sliding vane air compressor was used to predict the behaviour of machines having different geometries operating at different conditions. The performance parameters which were calculated by the model were the free air delivery, power input and specific capacity which is defined as the free air delivery per unit of power input.The model also included the study of the effects of Oil injection on these mentioned compressor performance parameters. The paper describes the simulation model developed incorporating an analysis Of the effects of the oil injected into the compressor on lhe thermodynamic processes taking place in …

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A Study On Ring Pack Lubrication In Internal Combustion Engine, I Mshoro Dec 1998

A Study On Ring Pack Lubrication In Internal Combustion Engine, I Mshoro

Tanzania Journal of Engineering and Technology (TJET)

Most efthe lubricating oil from Internal Combustion Engine (ICE) is lost through piston rings. Hence, in order to optimally reduce ICE oil consumption, a better insight into tribology of the ring pack is required. This can only be achieved by an inwroved characterization of the lubricant behaviour within the opelating environment of the engine. In The present ieork, an optical tcchnique using laser- induced fluorescence was employed to measure oil film thickness within the ring pack. The experiment was conducted on a Phaser 1000 Series engine, whereby optical access to the ring pack was achieved by a fused silica-window positioned …

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Extracting Consistent Weight Ratio Matrices From Inconsistent Judgement Matrices., Christian Alphonce Dec 1998

Extracting Consistent Weight Ratio Matrices From Inconsistent Judgement Matrices., Christian Alphonce

Tanzania Journal of Engineering and Technology (TJET)

The Analy,'ic Hierarchy Process (AHP) developed by Saaty Inore (han a decade ago has been widely applied in diverse decision making problenls ranging from socio-economic planning to engineering designs. One of the basic steps of this popular decision support tool is concerned with estimating a ratio scale of a set of entities from their inconsistent pairwise comparison judgement matrix. A number of estimation procedures for this purpose have been proposed. These include Saaty's eigenvector meihod, various geometric means methods, and methods using logarithmic least squares, least squares. and means Transformanons, amongst O,'hers. One Thing conunon to all these Inethods is …

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Analysis Of The Analytic Hierarchy Process Methodologies, C B Alphonce, C M. Brugha Dec 1998

Analysis Of The Analytic Hierarchy Process Methodologies, C B Alphonce, C M. Brugha

Tanzania Journal of Science

We review various methodologies for estimating the impact scores of alternatives on criteria within the Analytic Hierarchy Process (AHP). The results show that the geometric mean method for retrieving impact scores from judgment matrices and the weighted geometric mean aggregation rule provide a best fit to the underlying structure of the problem.

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A Universal Space Group Code In The Natural Science, M E Kamwaya Dec 1998

A Universal Space Group Code In The Natural Science, M E Kamwaya

Tanzania Journal of Science

A more systematic and universal cell-edge rule is proposed, in which the criterion in the determination of space groups (except for the cubic and trigonal systems) should be a ˃ b ˃ c. This leads to having two setting in the tetragonal and hexagonal systems, while in the monoclinic a third setting is added based on when angle a ≠ 90o.

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On Intamolecular Hydrogen Bonding Of O- Hydroxyaromatic Schef Bases And Related Molectules: Structre Of N-P- Chlorobenzylidene -2- Hydroxyaniline, Me Kamwaya Dec 1998

On Intamolecular Hydrogen Bonding Of O- Hydroxyaromatic Schef Bases And Related Molectules: Structre Of N-P- Chlorobenzylidene -2- Hydroxyaniline, Me Kamwaya

Tanzania Journal of Science

C13H10NOCl, Mr = 231.682, F(000) = 480, Z = 4, Dc = 1.387, Dm = 1.385 mgm-3, V = 1109. 53A, is monoclinic, space group P21/n with a = 13.033(4), b = 5.869(7), = 14.77 (4) A, and ß = 78.9(2)0. Least squares refinement led to a final R-value of 0.0539 for 520 reflexions. The presence of a five-membered intramolecular hydrogen bond in N-p-chlorobenzylidene-2-hydroxyaniline is established.

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Cultivating The Edible Oyster Mushroom Pleurotus On Sawdust, Fss Magingo Dec 1998

Cultivating The Edible Oyster Mushroom Pleurotus On Sawdust, Fss Magingo

Tanzania Journal of Science

The edible mushroom Pleurotus pulmonarius was grown on pasteurized saw dust supplemented with either Crotalaria ochroleuca (N2- fixing legume) or with chicken manure. Inoculated, unsupplemented sawdust acted as control. Sawdust supplemented with C. ochroleuca biomass yielded the highest fresh weight of the mushroom with a biological efficiency (B.E) of 83%. Sawdust supplemented with chicken manure had a 67% B.E., while control gave the least harvest (B.E. = 32%). Reasons for the differences are discussed.

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Heavy Metal Pollution In Lake Victoria, J. W. A. Kandoro, M. H. Mikidadi Dec 1998

Heavy Metal Pollution In Lake Victoria, J. W. A. Kandoro, M. H. Mikidadi

Tanzania Journal of Science

This work presents the Energy dispersive x-ray flouorences (EDXRF) analysis of water and plant samplesfrom Lake Victoria at Mwanza for heavy metal pollution. Water and plant (Water hyacinth) samples were collected from Lake Victoria around Mwanza municipality from twenty seven locations. There were varying elemental concentrations from different locations reflecting the activities carried out in the vicinity of the lake. Maximum concentration values of up to 1640 mg/L for Pb, 23.3 mg/L for Mn, 42.8 mg/L for Cr, 15.1mg/L for Pb, 23.3mg/L for Cu, and 742.5 mg/L for Zn, were observed. Possible sources of the elements are discussed, from which …

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A Person Computer Programme For Fitting Of Moessbauer Spectra, J. W. A. Kandoro Dec 1998

A Person Computer Programme For Fitting Of Moessbauer Spectra, J. W. A. Kandoro

Tanzania Journal of Science

A Computer code for fitting spectra obtained in Moessbauer spectroscopy on a personal computer is described. The code is designed around a least-squares routine which fits the characteristics peaks in a Moessbauer spectrum with Lorentzian shaped peaks and the background of a spectrum with a polynomial function. The least squares routing is based on the Newton-Raphson algorithm. The method is implemented in a computer program written in quick basic for which prove that the program in quick basic for IBM compatible personal computer. Tests are described which prove that the program is able to provide reliable values for the parameters.

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