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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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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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Tracking The Trochoid On Safari, Andrew Simoson May 1999

Tracking The Trochoid On Safari, Andrew Simoson

ACMS Conference Proceedings 1999

While on sabbatical in Dar es Salaam in 1997–98, I was tasked to be the department’s seminar director and discovered that a dearth of speakers roam about in east Africa; so I opted to set up a lecture tour for myself to include Zambia, Zimbabwe, and Botswana as well as Tanzania—and spoke about the envelope of curves generated by a series of line segments obtained when two runners attached by an ideal bungee cord (the line segments) proceed about a circular track. Herein we describe life in east Africa and show that those envelopes are trochoids.

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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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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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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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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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Bottom Reflection In A Shallow Tidal Bay, S B. Mahongo Dec 1998

Bottom Reflection In A Shallow Tidal Bay, S B. Mahongo

Tanzania Journal of Science

Bottom reflection of short-wave radiation was investigated using measurements taken from a platform in a shallow tidal lagoon on the eastern coast of Zanzibar, the Chwaka bay. Measurements were taken from 18 January to 9 February, 1996. The investigation was facilitated using a simple model of shallow water reflectance. The presumption that bottom reflection plays a significant role in the heat budget of the bay has been found to be incorrect. The computed mean value of the flux due to bottom reflection during this period was only of the order of 2Wm-2, and it is unlikely that variations …

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Development And Evaluation Of A New Soil Erosion- Productivity Index Model (Sepim), Metthew Mulengera Jun 1998

Development And Evaluation Of A New Soil Erosion- Productivity Index Model (Sepim), Metthew Mulengera

Tanzania Journal of Engineering and Technology (TJET)

A soil erosion-productivity model which considers rhe effect of soil water storage Capacity. crop evapotranspiration, soil chemical and physical properties inrporrantfor Crop growth has been developed. The model is shown to give good predictions and it promises to be an improvement over the former productivity Index (PI). It also promises to give more reliable results than the currently used /nodels which consider only soil water storage capacity and crop e ' 'apotransp iration.

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Global Warming: A Threat To Human Societies And Natural Ecosystems, Yunus D. Mgaya Dec 1997

Global Warming: A Threat To Human Societies And Natural Ecosystems, Yunus D. Mgaya

Tanzania Journal of Science

The possible influences of increases of mean sea surface temperatures are briefly reviewed. It is virtually certain that human activities are changing the composition and behavior of the atmosphere, leading to increased concentrations of greenhouse gases. Recent analyses and model predations show that risks to human societies and natural ecosystems from enhanced greenhouse effect may be large. A rising sea level could result in quite dramatic changes in maritime boundaries (as states to act to protect their maritime zones. It is concluded that in setting management goals with respect to mitigating the effects of global warming, one needs to recognize …

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Evidence For A Shore-Normal Energy Gradient And Its Character In The Speiekeroog Back Barrier Tidal Flats, German North Sea Coast, N Nyandwi Dec 1997

Evidence For A Shore-Normal Energy Gradient And Its Character In The Speiekeroog Back Barrier Tidal Flats, German North Sea Coast, N Nyandwi

Tanzania Journal of Science

Sediment distribution in the Spiekeroog backbarrier tidal flats has been studied with the aim of identifying the factors controlling their deposition. Form the mainland coast northwards three physiographic units are recognizable namely, the tidal flats adjacent to the coast, the tidal channels with the intervening flats and the dunes and tidal flats adjoining Spiekeroog island. The areal distribution of the sand fraction (˂4.0 phi) shows a shore normal energy gradient with increasing energy towards the sea. Very fine sands are found very close to the mainland coast, fine to very fine in the central part and fine sand on the …

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Characterization Of Iron Sulfides Form Lake Victoria Gold Field, Jwa Kondoro, Ca Kiwanga Dec 1996

Characterization Of Iron Sulfides Form Lake Victoria Gold Field, Jwa Kondoro, Ca Kiwanga

Tanzania Journal of Science

Iron sulphides form the Lake Victoria gold field have been characterized using Mossbauer spectroscopy. Thirteen iron sulphide samples have been categorized into four groups depending on which of the following phases is dominant: monoclinic pyrrhotite, hexagonal pyrrhotite, pyrite or non sulphide phases. A discussion on the characterization of the different phases is given in the paper

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Dispersion Of Heavy Metals Along Msimbazi River Basin In Dar Es Salaam, Jwa Kondoro Dec 1996

Dispersion Of Heavy Metals Along Msimbazi River Basin In Dar Es Salaam, Jwa Kondoro

Tanzania Journal of Science

Several locations of Msimbazi River, a prominent river basin passing through the urban area of Dar es Salaam into the Indian Ocean were sampled for about six months. The sampled specimens of water and sediments were investigated for the extent of heavy metal pollution using atomic Absorption Spectrophotometry (AAS) and X-Ray Fluorescence analysis (XRF) techniques. The major elements of interest in this study were Pb, Cd, Zn, Cu and Cr. Water analysis showed low concentrations for most of the elements. However, sediments showed significant concentration level in various stretches of the river basin for certain elements. The report analyses distribution …

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Application Of Multivariate Analysis In The Exploration For Tin In Granites: A Study Of Granites From Northwestern Tanzania Using Discriminant Function And Factor Analysis, J.R. Ikingura Dec 1995

Application Of Multivariate Analysis In The Exploration For Tin In Granites: A Study Of Granites From Northwestern Tanzania Using Discriminant Function And Factor Analysis, J.R. Ikingura

Tanzania Journal of Science

Variations in major and trace element Composition of granites from Karagwe-Ankolean (NE Kibaran) belt in northwestern Tanzania have been investigated by factor analysis and discriminant function statistical methods, The variations are attributed to three main factors. Factor 1 is positively loaded with CaO, MgO, Fe2O3 (Fe total), TiO2, MnO, Ba, Sr, Zr and Y, and negatively loaded with P2O5, SiO2, B and Rb. Factor 2 is positively loaded with Na2O, P2O5 Mno, Sn, Li, Rb and Y, and negatively loaded with TiO2, K2 …

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Uplift And Erosion Of The Livingstone Basin Rift Flanks, Malawi (Nyasa) Rift, East Africa: Apatite Fission Track Analysis, Mbede E. I Dec 1995

Uplift And Erosion Of The Livingstone Basin Rift Flanks, Malawi (Nyasa) Rift, East Africa: Apatite Fission Track Analysis, Mbede E. I

Tanzania Journal of Science

Apatite fission track (AFT) dating is a method applied in neotectonic studies of sedimentary basin and in constraining uplift histories of rift flanks. Dating of 20 AFT samples of basement rocks flanking the Livingstone (Karonga/Tukuyu) basin on the northern edge of the Malawi (Nyasa) rift is used to analyse the uplift and erosionofthe basin flanks. Results suggest that in the Livingstone basin, rift-related uplift and erosion of the flanks has modified the topographic patterns. The high elevation of the Livingstone Mountains is related to regionally distributed isostatic rebound, whereas the topography of the hanging wall flank has probably been severely …

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Gravity Data Interpretation Of The Usangu Baisin Tanzania, I.M. Marobhe, E.I. Mbede Dec 1995

Gravity Data Interpretation Of The Usangu Baisin Tanzania, I.M. Marobhe, E.I. Mbede

Tanzania Journal of Science

The shape and geometry of Rift of basins is best expressed by looking at the depth to basement maps. It is now an accepted idea that the Rift basins are spoon shaped bounded on one side by a border fault (BF) which is normally the side of maximum sediment deposition. Gravity data from Usangu Basin collected by Amoco in 1985 are here interpreted to decipher the shape and the geometry of the Basin. Results suggest that the Usangu basin shape is similar to the other Rift Basins within the East African Rift System (EARS). The basin, is however, traversed by …

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Natural Zeolites For Pollution Control An Overview, M.M. Makweba Dec 1995

Natural Zeolites For Pollution Control An Overview, M.M. Makweba

Tanzania Journal of Science

Natural zeolites are minerals characterized by a framework of alumino-silicate whose structure contains channels occupied by water and exchangeable cations. The common known zeolites which occur in sedimentary rocks of volcanic origin include analcime, clinoptilolite, heulandite laumontite, philipsite, chabazite, erionite and mordenite. The zeolites have been studied in detail on their physical and chemical propertied. The ability of zeolite minerals like clinoptilolite to remove Cs-137 and Sr-90 from radioactive waste waters and to remove ammonium ions from municipal waste waters has been a milestone for zeolites to be applicable in pollution control. In Tanzania, zeolites occurrences have been reported in …

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Algal Stromatolites From The Late Permian Lacustrine Sediments Of Tanzania, C.Z. Kaaya Dec 1995

Algal Stromatolites From The Late Permian Lacustrine Sediments Of Tanzania, C.Z. Kaaya

Tanzania Journal of Science

Thin bed of algal stromatolites and oolites occur within a distinct stratigraphic unit (60-120 m thick) in the Late Permian (Karoo) lacustrine sedimetns of the Ruhuhu Basin in SW Tanzania. The stromatolites vary from a few centimeters to 50 cm high and exhibit 4 morphotypes: 1) bulbous or domal 2) columnar. Branching and non-branching varieties are common in the two morphotypes. The other two are : 3) laminated mats and 4) oncolites. All four types may occur in one bed. Filamentous algae were responsible for the building up of the stromatolites in which there was more precipitation of calcite than …

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Determination Of Tine In Geological Samples By Energy Dispersive X-Ray Fluorescence With A Secondary Target, J. M. J. Kahatano, M. Mwambeule Dec 1995

Determination Of Tine In Geological Samples By Energy Dispersive X-Ray Fluorescence With A Secondary Target, J. M. J. Kahatano, M. Mwambeule

Tanzania Journal of Science

Tin has been determined in seven international geochemical reference samples with energy-dispersive X-Ray Fluorescence using an X-ray tube with a secondary target, after optimization of the working parameters and instrument settings. The tin values obtained in this work quite satisfactorily lie within ranges reported in the literature or recommended by the suppliers of the reference samples. The method can therefore be applied to supplement other analytical techniques in the elemental analysis of geochemical samples.

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Physical Controls Of Mud Deposition In A Backbarrier System, Spiekeroog Island German Wadden Sea, N. Nyandwi Dec 1995

Physical Controls Of Mud Deposition In A Backbarrier System, Spiekeroog Island German Wadden Sea, N. Nyandwi

Tanzania Journal of Science

The areal distribution of the mean grain size of the sand fraction indicates presence of a shore-normal energy gradient with a shoreward fining from a mean grain size of 2.0 phi (0.25 mm) on Spiekeroog island to 3.5 phi (0.09) mm) near the dyke which forms the landward boundary of the tidal flat. This energy gradient is also reflected by the shoreward increase in the mud content of the sediment. Until recently, the relation of the mud distribution to the energy level variation in the Wadden Sea was not clearly known. Purely mud zones (˃ 50% mud) occur in the …

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