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Articles 451 - 480 of 484
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A Universal Space Group Code In The Natural Science, M E Kamwaya
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.
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.
A Person Computer Programme For Fitting Of Moessbauer Spectra, J. W. A. Kandoro
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.
Bottom Reflection In A Shallow Tidal Bay, S B. Mahongo
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 …
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 …
Characterization Of Iron Sulfides Form Lake Victoria Gold Field, Jwa Kondoro, Ca Kiwanga
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
Dispersion Of Heavy Metals Along Msimbazi River Basin In Dar Es Salaam, Jwa Kondoro
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 …
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 …
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 …
Gravity Data Interpretation Of The Usangu Baisin Tanzania, I.M. Marobhe, E.I. Mbede
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 …
Natural Zeolites For Pollution Control An Overview, M.M. Makweba
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 …
Algal Stromatolites From The Late Permian Lacustrine Sediments Of Tanzania, C.Z. Kaaya
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 …
Determination Of Tine In Geological Samples By Energy Dispersive X-Ray Fluorescence With A Secondary Target, J. M. J. Kahatano, M. Mwambeule
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.
Physical Controls Of Mud Deposition In A Backbarrier System, Spiekeroog Island German Wadden Sea, N. Nyandwi
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 …
Stratigraphy And Tectonic Evolution Of The Palaeoproterozoic Usagaran Belt In South-Eastern Tanzania, A.H. Mruma
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 …
The Mozambique Of Eastern Tanzania: Evidence For Pan-African Reactivation Of Early Proterozoic Usagaran Basement, M.A.H. Maboko
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 …
Weathering On The Alkaline Rocks Of The Mbozi Gabbro Syenite Complex Sw–Tanzanian, East Africa, M.K.D. Mutakyahwa
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 …
Palynostratigraphy Of Cretaceous Sediments, Rufiji Basin, Tanzania, E. Msaky
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 …
Silica Spherules In Chrysoprase From Haneti-Itiso Area, Cental Tanzania, E.P. Malisa
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 …
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 …
Aerosol Composition As A Function Of Particles Size, Y. I. A. Koleleni, R. Van Grieken
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.
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.
Meteostat Wefax Image Data Acquisition From The Weather Satellite Receiver, A. J. Mwambela, A. Purvis
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.
An Account Of Sandbank Depositional Modes, Menai Strait U. K, N. Nyandwi
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 …
Surface Carbon Formation On Pt/ˠ-A12o3 From C3 And C4 Hydrocarbons Part 1: Kinetics Of Carbon Formation, L.L. Mkayula
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 …
Surface Carbon Formation On Pt/ˠ-A12o3 From C3 And C4 Hydrocarbons Part Ii: Characterization Of Coked Samples, L.L. Mkayula
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 …
On The Entropy Of Kiswahili, Luhanga M.L, T.G.B. Nyambo
On The Entropy Of Kiswahili, Luhanga M.L, T.G.B. Nyambo
Tanzania Journal of Science
Cover and King’s gambling approach to the estimation of the entropy of English is used to estimate the entropy of Kiswahili. Experimental results obtained show that Kiswahili has average entropy of approximately 1.76.
A Preliminary Chemical Survey Of The Salt Deposits And Evaporates Of Lake Balangida, Hanang District, Tanzania, N. Mwakoba, D. Mosha, K. Schrøder
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 …
On The Field-Induced Infra-Red Absorption Of Gaas, Frederick Ngawo Onyango
On The Field-Induced Infra-Red Absorption Of Gaas, Frederick Ngawo Onyango
Tanzania Journal of Science
A theoretical survey of electric field–induced effects on one-and two-phonon absorption of GaAs is presented. The eigen-values and hence eigen-vectors are calculated for an external field applied along [001] and dependence of electro–absorption on the direction of radiation polarization established.
Theoretical Evaluation Of Selective Radiation–Absorbing Surface, K.R. O’Shea
Theoretical Evaluation Of Selective Radiation–Absorbing Surface, K.R. O’Shea
Tanzania Journal of Science
An algol computer program is described, by means of which the spectral reflectivity for any angle of incidence may be calculated for a surface consisting of up to two thin absorbing films on a bulk substrate. The values of optical constant, n and k, for the materials used and also the thickness of the films, are the only data required. Calculated reflectivities have been shown to be consistent with experimental results.