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Stratigraphy And Tectonic Evolution Of The Palaeoproterozoic Usagaran Belt In South-Eastern Tanzania, A.H. Mruma Dec 1995

Stratigraphy And Tectonic Evolution Of The Palaeoproterozoic Usagaran Belt In South-Eastern Tanzania, A.H. Mruma

Tanzania Journal of Science

The palaeoproterzoic Usagaran Belt is bordered by the Archaean Tanzanian Craton to the NW and the Mozambique Belt to the east. It is made up of the following three stratigraphic units:- (i) The lithodemic sillimanite, kyanite and cordierite gneiss lithodemes and pyroxene-garnet amphibolite lithodemes (ii) The lithostratigraphic Konse Group : greenschist to lower amphibolite facies metasedimentary and metavolcanic formations. (iii) The metavolcanic Ndembera Group; a possible lateral equivalent of the konse. Furthermore, the belt contains a post-tectonic gabbro-granitoid suite. The mutual stratigraphic relationship of the konse and Isimani has been a matter of dispute. However, the field observations described in …

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The Mozambique Of Eastern Tanzania: Evidence For Pan-African Reactivation Of Early Proterozoic Usagaran Basement, M.A.H. Maboko Dec 1995

The Mozambique Of Eastern Tanzania: Evidence For Pan-African Reactivation Of Early Proterozoic Usagaran Basement, M.A.H. Maboko

Tanzania Journal of Science

The high grade metamorphic rocks of Eastern Tanzania belong to two distinct tectonothermal belts; the early Proterozoic Usagaran Belt and the late Proterozoic (Pan–African) Mozambique Belt. Rocks of the Usagaran Belt, which locally sow evidence of eclogite facies metamorphism, experienced peak metamorphic conditions at ⁓ 2000 Ma. Tectonic activity in the Usagaran added at ⁓ 1800 Ma with the emplacement of post-organic granites. In contrast, the Mozambique Belt, which is characterized by extensive granulite complexes, experienced peak metamorphic conditions at about 700 Ma. Due to the similarity of both structural trends and metamorphic grade, the boundary between the two belts …

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Weathering On The Alkaline Rocks Of The Mbozi Gabbro Syenite Complex Sw–Tanzanian, East Africa, M.K.D. Mutakyahwa Dec 1995

Weathering On The Alkaline Rocks Of The Mbozi Gabbro Syenite Complex Sw–Tanzanian, East Africa, M.K.D. Mutakyahwa

Tanzania Journal of Science

The Mbozi gabbro syenite complex is about 800 Ma and is associated with the Bukoban tectonic episode. Tectonically it follows the regional strike direction of the Ubendian System, which is a part of the polycyclic Mozambique mobile belt. The complex is a typical ring structure with the central part down-faulted. Deep weathering profiles on the ring structure were developed on a peneplain and as a result of uplift intersected hilly landscape of early tertiary times. The truncated 5-15m thick weathering profiles occur on three rock types, olivine gabbro, pyroxenite and nepheline perthite syenite (pethoste). The chemical and mineralogical processes of …

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Palynostratigraphy Of Cretaceous Sediments, Rufiji Basin, Tanzania, E. Msaky Dec 1995

Palynostratigraphy Of Cretaceous Sediments, Rufiji Basin, Tanzania, E. Msaky

Tanzania Journal of Science

Cretaceous sediments from Luhio - 1 borehole drilled in the Rufiji basin yielded a palynomorph assemblage of spromorphs and dinoflagellate cyst species. The age of the sediments penetrated ranges from Early Cretaceous (Albian) to Late Cretaceous (Senonian). The Early Cretaceous is characterized by presence of the following dinocyst key species: Litosphaeridium arundum, Dinopterygium tuberculatum, Florentinia Cooksoniae, Systematophora cretacea and Oligosphaeridium pulcherrimum. The Late Cretaceous (Senonian) is characterized by the presence of the following dinocyst key species: Cannosphaeropsis utinensis, Dionogymnium pustulicostatum, Florentinia ferox, Odontochitina porifera, Odontochitina operculata, Xenascus sarjeantii and Xiphophoridium asteriforme …

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Silica Spherules In Chrysoprase From Haneti-Itiso Area, Cental Tanzania, E.P. Malisa Dec 1995

Silica Spherules In Chrysoprase From Haneti-Itiso Area, Cental Tanzania, E.P. Malisa

Tanzania Journal of Science

Apple green gem quality chrysoprase from haneti-Itiso area, central Tanzania was studied. Under the microscope the chrysoprase shows highly disordered spherules which are concentric. Composed of bipyramidal quartz, chalcedony quartzite and opal-A. The spherules were classified into four main types according to the shell arrangement. The diameter of the spherules ranged from 40 μm 77 μm. Fluid inclusion types in bipyramidal quartz were monophasic low temperature type. Mineralogical properties indicated refractive indices to be 1.548 to 1.553 (±0.002), mean specific gravity 2.56, hardness about 7 on Moho’s scale, inert to ultraviolet radiation, green though Chelsea filter, and absorption in the …

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Model For Complete Drawdown Of Floating Solids In Stirred Tank Reactors, J Mmbaga Dec 1994

Model For Complete Drawdown Of Floating Solids In Stirred Tank Reactors, J Mmbaga

Tanzania Journal of Engineering and Technology (TJET)

A Semi-empirical model has been developed on the basis of Kolmogoroff's theory of isotropic turbulence to determine the minimum drawdown speed for floating solids in a mechanically agitated vessel. An adjustable pa- rameter in the model is found to be afunction of impeller type and position in a vessel. A simplified representation of macroscopicflow pattern, rep- resenting the circulation flow in a vessel depending on impeller pumping characteristic is developed to account for recirculation pattern.

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Optimum Geometrical Parameters For Prismatic Folded Plate Roofs: System- Atic Search Approach, N Mwitta Dec 1994

Optimum Geometrical Parameters For Prismatic Folded Plate Roofs: System- Atic Search Approach, N Mwitta

Tanzania Journal of Engineering and Technology (TJET)

Folded plate structures have unique structural advantages over conven- nonal beam-and-slab structural forms. Selection of optimum geometrical parameters in design would make folded plate roofs more appealing to the national construction industry in terms ofcost. This paper presents a study on shape optimization of prismatic folded plate roofs for minimum weight of the structure per unit covered area. A computer based systematic search approach has been employed.for the optimization study, while the tranyeer matrix method has been used for analysis. Curves opriinum geometrical parameters versus span have been pre sented for three commonly used shapes of prismatic folded plate roofs. …

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Regionalization Of Hydrologic Information In Tanzania (Low Flows), Onyekwuluje C Jun 1994

Regionalization Of Hydrologic Information In Tanzania (Low Flows), Onyekwuluje C

Tanzania Journal of Engineering and Technology (TJET)

Hydrologic infornjation is required for the planning and design Ofwater resource projects. However, Hydrologic infonnation is always lacking at points of interest. Regionalization is ained at estimating hydrologic infor- mation such as low flow statistics at ungauged sites. Hydrologic informa- tion from 63 catchments in Tanzania has been analysed. In this paper, pooled flow duration curves for 1, IO, 30, 60, and 90 days duration have been established. Regression equations between the low flow indices (i.e. 95 percentile and for a IO day duration, average annual yield (AAY), av- erage daily flow (ADE)) and catchment characteristics were developed. The pooled …

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Influence Of Turbulence On Methane-Air Flame Speed, E Mushi Jun 1994

Influence Of Turbulence On Methane-Air Flame Speed, E Mushi

Tanzania Journal of Engineering and Technology (TJET)

Experimental study Of the influence qfturbulence on flame speed for meth- ane-air mixtures has been conducted in afan stirred bomb using schlieren photography. It has been observed that turbulence increases flame speed but above KLe=O. 18 (KLe is the product Of the dimensionless Karlovitz flame stretch factor and the Lewis number) turbulence quenches the flame. Inminarflame kernel is observed to prevail in the early stages of flame development in a turbulent mixture. Further, the laminar burning velocity plays a significant role in turbulent combustion. It is proposed that the increase in flame speed is a result of flame wrinkling.

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A Conceptual Approach To Water Resources Management For A Catchment In Tanzania, F Mwanuzi Dec 1993

A Conceptual Approach To Water Resources Management For A Catchment In Tanzania, F Mwanuzi

Tanzania Journal of Engineering and Technology (TJET)

In hydrology/Water resources, normally rainfall data are available for longer periods than runoff data. Many attempts have been made to extend these runoff data by using system approach and conceptual models. The conceptual approach to simulate runoff at the outlet ofa catchment is based on the physical processes involved in the transformation of rainfall into runoff (river flow). In this paper a conceptual model, (SEAMOD) has been used. This model has a limited number of parameters to optimize when compared to other models like the sacramental model. Also it requires less input data. The model assumes that the storage is …

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A Check Parameter Method For Use In Designing Relays, H Kadete Dec 1993

A Check Parameter Method For Use In Designing Relays, H Kadete

Tanzania Journal of Engineering and Technology (TJET)

Low quality magnetic steel available locally has been successfully used as core material for a relay. New design principles as well as construction procedure used in development of a prototype are presented. Then the new approach is assessed and found to deliver acceptable accuracy.

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Temperature-Based Predictions Of Wind Speed, Relative Humidity, Rainfall, Absolute Humidity, Vapour Pressure And Dew Point, E. C. Njau Dec 1993

Temperature-Based Predictions Of Wind Speed, Relative Humidity, Rainfall, Absolute Humidity, Vapour Pressure And Dew Point, E. C. Njau

Tanzania Journal of Science

We derive from first principles analytical expressions that give each of the following meteorological parameters in terms of (air) temperature: wind speed, relative humidity, rainfall, absolute humidity, vapour pressure and dew point. The practical validity of these expressions has been clearly ascertained using past meteorological records. Since air temperature is one of the easiest meteorological parameters to predict (Njau, 1991, 1994), the derived analytical expressions are simple and convenient tools by means of which wind speed, absolute humidity, rainfall, relative humidity, vapour pressure and dew point may be predicted. In this paper we demonstrate and explain how the derived analytical …

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Aerosol Composition As A Function Of Particles Size, Y. I. A. Koleleni, R. Van Grieken Dec 1993

Aerosol Composition As A Function Of Particles Size, Y. I. A. Koleleni, R. Van Grieken

Tanzania Journal of Science

Analysis of air particulate matter for various particle diameters 0.25-0.5 mm: 0.5-1 mm; 1-2 mm; 2-4 mm; and 4-8 were performed to investigate the contribution of both fine and coarse particles in environmental content. The abundance in the highest percentage concentration relative to particle diameters has shown interesting diagonal pattern with most of the elements ranging within 0-2%; 0.20%; 20-40%; 40-70%: and 70-100% respectively for different particle sizes. For the lowest percentage concentration range it is within 0-20%. In general the sum of elemental concentration provides a significant important result as far as pollution studies are concerned.

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Mathematical Analysis Of Marketing Costs Of Agricultural Crops: The Case Of Coffee, C.B. Alphonce Dec 1993

Mathematical Analysis Of Marketing Costs Of Agricultural Crops: The Case Of Coffee, C.B. Alphonce

Tanzania Journal of Science

This paper describes a case study in which a zero one mixed integer linear programming model was formulated and used to analyze marketing costs of coffee marketed by Kagera Co-operative Union. The solution of the model indicated a potential decrease of about 18% in the marketing costs. It is hoped that the model can be applied to other crops.

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Seasonality Of Salinity, Temperature And Dissolved Oxygen In The Inshore Waters Of Zanzibar In Response To The Local Meteorological Conditions, S. M. Mohamed Dec 1993

Seasonality Of Salinity, Temperature And Dissolved Oxygen In The Inshore Waters Of Zanzibar In Response To The Local Meteorological Conditions, S. M. Mohamed

Tanzania Journal of Science

Salinity, temperature and dissolved oxygen of the coastal surface waters off the coast of Zanzibar were investigated. The water showed an annual variation in properties reaching their maximum temperature and minimum salinity towards the end of the northeast monsoon and their minimum temperature and maximum salinity towards the end of southeast monsoon. However, results also show that local meteorological conditions have a profound impact on the hydrography of the area.

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Meteostat Wefax Image Data Acquisition From The Weather Satellite Receiver, A. J. Mwambela, A. Purvis Dec 1993

Meteostat Wefax Image Data Acquisition From The Weather Satellite Receiver, A. J. Mwambela, A. Purvis

Tanzania Journal of Science

This paper describe the development and implementation of satellite image data acquisition interface board using a programmable peripheral interface device, the intel 8255 PPI, to be used between a secondary data weather satellite receiver and an IBM PC. Brief details of both hardware and software design implementation, to transfer and store data are given.

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Optimum Design For Spring With Orthogonal Design Method, Han Fu - Jie Jun 1993

Optimum Design For Spring With Orthogonal Design Method, Han Fu - Jie

Tanzania Journal of Engineering and Technology (TJET)

Orthogonal design method is a sort of direct optimum method, by which the op- timal result may be obtained through simple computation and analysis. This method has gained increasingly extensive interest in scientific research, engineering design, end production management as well. The orthogonal table is the basic instrument for carrying out optimum design with orthogonal design method. It is a mathernatical table established On the basis Of the idea of isostatic distribution. As various levels may appear in any column, it makes a partial experiment contain levels of all factors furthermore. RII combina- tions of any two columns may appear …

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Theoretical Analysis Of Thermodynamic Consistency Of A Reiner-Rivlin Fluid, V.G. , Masanja Dec 1992

Theoretical Analysis Of Thermodynamic Consistency Of A Reiner-Rivlin Fluid, V.G. , Masanja

Tanzania Journal of Science

The thermodynamically admissibility of a Reiner-Rivlin fluid undergoing a two dimensional axisymmetric flow process has been investigated analytically. The Clausius-Duhem inequality shows dependence of the viscosity coefficients on kinematical quantities, hence no general restrictions can be made on the non-Newtonian viscosity coefficient. However specific restrictions have been made by considering a cubic degree fluid. It is concluded that the rheological equation of state is an approximate model of the constitutive behavior of a real fluid and that the thermodynamic consistency of a flow process can basically be proved numerically.

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An Account Of Sandbank Depositional Modes, Menai Strait U. K, N. Nyandwi Dec 1992

An Account Of Sandbank Depositional Modes, Menai Strait U. K, N. Nyandwi

Tanzania Journal of Science

Grain size distribution on the seabed and in the suspension were determined on an intertidal sandbank in Menai Strait, U.K. to establish both the mode of deposition and its stability against the strong tidal flows prevailing in the strait. Granulometric analysis showed typically three sediment population (log plot of cumulative curve) in the size range 4.0-3.0 phi and 1.5-1.0 phi with the middle on making the largest in all the samples. A probability plot of the cumulative curves however revealed on the average the lower (coarse) and upper (fine) truncation points to be lying at 1.5 phi and 3.0 phi …

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Surface Carbon Formation On Pt/ˠ-A12o3 From C3 And C4 Hydrocarbons Part 1: Kinetics Of Carbon Formation, L.L. Mkayula Dec 1992

Surface Carbon Formation On Pt/ˠ-A12o3 From C3 And C4 Hydrocarbons Part 1: Kinetics Of Carbon Formation, L.L. Mkayula

Tanzania Journal of Science

Carbon formation on an Esso reforming type catalyst Pt/γ-A12O3 by C3 and C4 hydrocarbons has been studied at atmospheric pressure and within a temperature range of 450-6000C using a microbalance capable of detecting up to 10-6 g by weight of coke. A kinetic model initially developed by Froment has been used to analyze the transient regime of coke versus time curves. Deactivation function-reaction mechanism relations have been proposed and applied to the coking results. Carbon deposition rates are highly dependent on temperature, partial pressures of reactant, nature and composition of reactions, and …

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Surface Carbon Formation On Pt/ˠ-A12o3 From C3 And C4 Hydrocarbons Part Ii: Characterization Of Coked Samples, L.L. Mkayula Dec 1992

Surface Carbon Formation On Pt/ˠ-A12o3 From C3 And C4 Hydrocarbons Part Ii: Characterization Of Coked Samples, L.L. Mkayula

Tanzania Journal of Science

The total surface area, pore size distribution, metal surface area, particle size and topography of coked Pt/γ-12O3 catalyst samples used in in part 1 of this series were measured and compared with those of a fresh catalyst. No significant changes in total surface areas of the coked catalyst was observed despite a high coke content in some samples. This is interpreted in terms of partial narrowing of mesopores that was confirmed by pore size distributions observations of high temperature coked samples. The platinum metal surface area of high temperature coked catalysts decreased with increase in temperature and …

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A Preliminary Chemical Survey Of The Salt Deposits And Evaporates Of Lake Balangida, Hanang District, Tanzania, N. Mwakoba, D. Mosha, K. Schrøder Dec 1992

A Preliminary Chemical Survey Of The Salt Deposits And Evaporates Of Lake Balangida, Hanang District, Tanzania, N. Mwakoba, D. Mosha, K. Schrøder

Tanzania Journal of Science

Lake Balangida is a typical salt-and –soda lake sharing many common hydrochemical features with the twenty or so hypersaline dischargeless lake of the African Gregory Rift Valley (Dead Sea to Lake Malawi). Sulphate content is however, comparatively exceptionally high but the single most contrasting dissimilarity is the virtual absence of fluoride. In previous reports, we have presented findings on the chemistry of the lake brines and inflows. In the present work, the salt deposits and evaporated which cover the lake after desiccation during the September-December dry spell are chemically examined. Salt and soda appear to occur in separate locations; the …

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Control System Design Program Based On Cascade Compensation, Fredrick Ishengoma Jun 1992

Control System Design Program Based On Cascade Compensation, Fredrick Ishengoma

Tanzania Journal of Engineering and Technology (TJET)

CAD is becoming more widely accepted in the design and analysis of control systems. A program has been developed for analyzing single-input single-output linear time-invariant control system. The application of the progranl for frequency domain design of cascaded phase lead and phase lag coinpensators is briefly discussed. Two examples to illustrate the program are presented.

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Optimization Of Dispersed Flor Pond For Bacterial Removal, Mayo A. W Jun 1992

Optimization Of Dispersed Flor Pond For Bacterial Removal, Mayo A. W

Tanzania Journal of Engineering and Technology (TJET)

The design of waste stabilization ponds is seldom done with consideration of optimum pond dimensions. The analysis of pond dimensions within practical limits in dispersed flow ponds on the basis of minimum cost for the predetermined bacterial remova) ef ficiency, with the aid of computer is presented. The data collected in the pilot and full scale waste stabilization ponds at the University of Dar es Salaam Was used as input to the computer program. The results shows that pond configuration and climatic conditions which have influence on bacterial mortality rate have a re:narkable influence on pond cost

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Hydrodynamic Stability Of The Breakwater Extension At Rrviksand, Norway, Alfonse Dubi Jun 1992

Hydrodynamic Stability Of The Breakwater Extension At Rrviksand, Norway, Alfonse Dubi

Tanzania Journal of Engineering and Technology (TJET)

The fishing port of Årviksand in Norway, which is situated on an open coast, is artificially harboured by breakwaters. The northern and southern breakwaters which were built in 1930—ies and 1950—ies respecti vely have been on several occasions damaged by heavy storms. This resul ted in the need for further protection by extending the northern breakwater. This paper describes one of the hydrodynamic tests on the breakwater extension. The breakwater, with a berm breakwater concept design, is subjected to the joint probability of sea level elevation and wave heights (in other 'fatigue" test). words , It is found that cover …

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Evaluation Of Wind Data Records To Predict Extreme Extreme Wind Speeds In Tanzania, L Lwambuka Jun 1992

Evaluation Of Wind Data Records To Predict Extreme Extreme Wind Speeds In Tanzania, L Lwambuka

Tanzania Journal of Engineering and Technology (TJET)

The progress made towards evaluation of local wind data records to pred ict extreme values of wind speeds in Tanzania is being presented . Records of wind data, stored continuously since 18 years, have been compiled and statistically processed. Extreme value theory of Fisher —Tippet Type I has been fitted into the data to abstract extreme values of wind speeds for locations at which the wind data records were obtained. A reliable wind map of Tanzania containing basic wind speeds at 18 locations across the country has been produced. The basic wind speeds are being recommended for des ign against …

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The Hydraulic Performance Of A Vortex Tube Foector, F Mtaro Dec 1991

The Hydraulic Performance Of A Vortex Tube Foector, F Mtaro

Tanzania Journal of Engineering and Technology (TJET)

The vorle.r tube silt exrrac/or consists of a pipe, rhe crest of which has a slit and lies flush across lhe canal bed.With minimal warer loss, I.oe bedload is extracted through lhe slil settling canal back ro the river, thus reducing or eliminating the bedload transported in main canal. Ihe resulting swirling flow phenomena is of complex nature and depends on sc conirol paramerers, as a result of which previous empirical design approaches have yielded conflicting guidelines. By means Of a simplified hydraulic system, the flow mechanism and energy in rhe can be determined.

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Flood Forecasting In Tanzanian Catchments, Omari Rumambo Dec 1991

Flood Forecasting In Tanzanian Catchments, Omari Rumambo

Tanzania Journal of Engineering and Technology (TJET)

Floods are still a problem to many countries in the world todate. Floods do cause damages to property and sometimes loss to human life. Flood control measures by structural and non—structural methods are avail able in the literature . However , structural flood control measures are financially infeasible in most developing countries today. Flood forecasting is a non—structural measure for reducing flood damages. It is a means of providing early The Li near f 1 ood warnings to flood prone areas . Perturbation Model has been appl ied for real time flood The Linear forecasting in Tan zanian catchments . …

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Experimental Investigations On The Behaviour Of Wood In Transverse Compression, A Mrema Dec 1991

Experimental Investigations On The Behaviour Of Wood In Transverse Compression, A Mrema

Tanzania Journal of Engineering and Technology (TJET)

Experimental investigations were done to study the behaviour of wood in transverse compress ion. Three key variables were incorporated in the experiments to study their influence on the •nriables were the orthotropic ratio of the behav iour. These material, the geometry of loading and that of the specimen . Deformation measurements were made at selected locations on test specimens by means of strain—gage based clip gages. Results from the experimental measurements were compared to previous deformation predictions made by a finite element analysis (9) . There is a very good agreement between measured values and those obtained trom the finite …

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A Finite Element Analysis Of Wood In Transverse Compression, A Mrema Dec 1991

A Finite Element Analysis Of Wood In Transverse Compression, A Mrema

Tanzania Journal of Engineering and Technology (TJET)

A two dimensional finite element analysis is utilized to predict the stress and strain distributions for wood in transverse compression. Important key var iables are incorporated into the ana lysis to define their influence on the stress and strain distributions. These variables are geometry of loading, geometry of specimen and the orthotropic ratio of the material. Based on the finite element analysis results, relationships are arising stress from developed relat ing maximum stress concentrations to the above three variables. possible appl ications of the results from this study relate to the development of more efficient design of connections such as …

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