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Ammonite Biostratigraphy Of The Jurassic Of Tanzania, S Kapilima

Tanzania Journal of Science

The present paper summarizes the previous biostratigraphical researches and incorporates the recent research findings on the Jurassic rocks in the coastal basin of Tanzania. The ammonites used for the biostratigraphical classification are from two sub-basins along the coastal belt of Tanzania: Mandawa (south) and Ruvu- Tanga (north). The oldest known ammonites from these basins are of Aalenian age. The biostratigraphical classification of the Jurassic sequence, on the basis of the vertical and horizontal distributions of the ammonite assemblages, permits the erection of eight sub stages of Jurassic: Upper Aalenian (Concavum-Zone), Bajocian (Humphrieasianum-Zone), Middle Callovian (Coronatum-Jason Zone), Upper Callovian (Lamberti-Athleta Zone), …

Bajocian Ammonites From Msata Hill (Lugoba Formation) In The Hinterland Of Dar Es Salaam, Tanzania, S Kapilima

Tanzania Journal of Science

Ammonites from the Middle Jurassic exposures of the Lugoba Formation at Msata, are described for the first time in Tanzania. Out of a number of ammonite fragments recovered from the bluish-green silty limestone (M3), only three fragments were fairly well preserved to permit their specific identification. Two species were identified: Dorsetensia cf. D. romani (OPPEL) and Oecotraustes (Paroecotraustes?) cf. angustus DOUVILLE. This ammonite assemblage is biostratigraphically correlatable with the Lower Bajocian Posidonia shale of the Kambe Limestone series in Kenya, in which similar ammonites species and other related Bajocian species have been described. Pending new discovery of ammonoid fauna and …

Petrology And Lithogeochemistry Of The Mineralized Tanzanite-Grossular Bearings Rocks In The Merelani-Lelatema Area, Northeastern Tanzania, Ep Malisa

Tanzania Journal of Science

The Merelani-Lelatema area, which is occupied by late Proterozoic metasedimentary rocks, lies along the Lelatema fault zone. The rocks are mainly pelitic and semi-pelitic gneisses, psammitic gneisses, hydrothermally altered rocks, crystalline dolostones, pegmatites and quartz veins. The occurrence of gem-quality tanzanite and grossular has been found to occur mainly in boudinaged pegmatitic veins and hydrothermal fracture fillings. These fracture fillings occur in brecciated and hydrothermally altered graphite-bearing gneiss in a mineral association containing glass-clear quartz, diopside, zoisite, graphite and calcite. The psammitic gneisses are more siliceous and enriched in feldspars. They are grouped into graphite-kyanite gneiss with thin interlayers of …

Heritability Of Cooking Time And Water Absorption Traits In Dry Beans (Phaseolus Vulgaris L.) Using A North Carolina Design Ii Mating Scheme, Fm Elia

Tanzania Journal of Science

Estimation of genetic variances, heritabilities and estimations of response to selection of the cooking time and water absorption traits of Andean gene pool of dry bean seed Phaseolus vulgaris L. were done. General combining ability (GCA) i.e. GCA males and GCA females, and Specific combining ability (SCA) were estimated. The parents were crossed in a North Carolina mating design II and genetic analysis was made on the F3 and F4. Both male and female effectations within sets for the cooking trait in F3 and F4 were highly significant for the traits studied. Variances due to General combining ability (GCA) and …

Heavy Metal Contamination Of Mangrove Sediments And The Associated Biota In Dar Es Salaam, Tanzania, Sd Mremi, Jf Machiwa

Tanzania Journal of Science

Mangrove wetlands are efficient in trapping pollutants that may have detrimental effects on mangrove dependent food chains. Mangrove ecosystems that are within urban areas are likely to suffer more from chemical pollution than those in rural areas. Heavy metals in mangrove plant parts, sediments and crabs from mbweni, msimbazi and mtoni mangrove ecosystems in Dar es salaam were analysed using an atomic absorption spectrophotometer, in order to assess the impact of heavy metal pollution on mangrove biota. Sediment samples from msimbazi and mtoni mangrove areas which are located within the city, had higher levels of pb, zn and cu than …

Levels Of Pesticide Residues In Water, Soil And Sediments From Southern Lake Victoria And Its Basin, Leonia Henry, Michale A Kishimba

Tanzania Journal of Science

Water, sediment and soil samples collected from Southern Lake Victoria and its basin were analysed for 76 organochlorine, organophosphorous, carbamate and pyrethroid pesticide residues. The samples were collected from sampling stations in nine districts on the Tanzanian side of the lake, namely Mwanza, Sengerema, Geita, Ngudu, Misungwi, Magu, Bunda, Tarime and Musoma Districts. DDT and HCH residues were the only detected pesticides. The concentration of total DDT was up to 1.6 mg/L in water, 600 mg/kg dry mass in sediments and 20 mg/kg dry mass in soil. The concentration of total HCHs were up to 0.2 mg/L in water, 132 …

Chemotaxonomic Distinction Of Selected Closely Related Acacia Species Using Chemical Properties Of Their Gum Exudates, Gs Mhinzi

Tanzania Journal of Science

Although Acacia senega var. senegal and Acacia senegal var. leiorhachis are regarded as being closely related botanically, their gum exudates have shown to possess different properties. The properties of the gum exudate from A. senegal var leiorhachis differ from that obtained from A. senegal var. senegal (widely accepted as the source of commercial gum arabic) by being much more viscous, less acidic and having higher proportions of insoluble gel fraction and nitrogen contents. The specific optical rotation values of the gum exudates from these two species have also been found to be different. It is proposed that some of the …

Corrosion Inhibition Of Carbon Steel By An Amine- Fatty Acid In Acidic Solution, Joseph Buchweishaija

Tanzania Journal of Science

The corrosion inhibition of carbon steel in 3% de-aerated NaCl acidic solution with amine–fatty acid corrosion inhibitor, KI384, was investigated at different temperatures using potentiodynamic polarization technique. The Corrosion rate was calculated in the presence and absence of inhibitor. The inhibition increased with an increase in inhibitor concentration and decreased with rise in temperature. The maximum percentage inhibitor efficiency was obtained at 35 oC. The percentage inhibition up to 99% was registered at a concentration of 10 ppm of KI384. The inhibitor acts as a mixed type at lower temperature and predominantly anodic at high temperature. The interrelationship between the …

Effects Of Chromium Uptake On The Growth Characteristics Of Eichhornia Crassipes (Mart.) Solms, Zk Rulangaranga, Al Mugasha

Tanzania Journal of Science

The uptake of chromium from fresh water by Eichhornia crassipes was studied under greenhouse conditions where the species was raised in culture solutions containing varying concentrations of chromium (VI) ions. There were positive correlations between the concentration of chromium in the culture media and the amounts of the metal accumulated in the tissues of E. crassipes at any given time. Furthermore, the total accumulated chromium in the tissues of E crassipes increased with increase in the duration for which the plant was exposed to the nutrient solutions containing chromium ions. Most of the absorbed chromium was accumulated in the roots …

Tectonic And Sedimentary Evolution Of The Coastal Basin Of Tanzania During The Mesozoic Times, S Kapilima

Tanzania Journal of Science

The present paper reviews and updates the stratigraphy and tectonic evolution of the coastal basin of Tanzania during the Mesozoic times based on the interpretation of existing palaeontological and stratigraphical information and supplemented by recent fieldwork investigations by the author. Tectonic events largely controlled the evolution of the coastal basin of Tanzania and the Indian Ocean. These included the Karoo rifting during Permo-Triassic, the break up of the Gondwana Supercontinent, which started with rifting in the Triassic period, the opening of the Somali basin in the Middle Jurassic, and the Cenozoic rifting along the East African rift system. The Karoo …

Eutrophication Of Kigoma Bay Lake Tanganyika, Tanzania, Fmm Chale

Tanzania Journal of Science

Studies carried out in Kigoma bay (Tanzania) and at a deep water offshore station in lakeTanganyika showed marked differences in the water characteristics at the two locations. At the pelagic station, the water was more transparent (mean 11.47 m) and poor in phosphorus (mean 6.46 mg p/1 and 2.23 p/1 total and soluble reactive p, respectively). The mean transparency value for the bay was 4.05 m, and the levels of total and soluble reactive phosphorus were 14.75 mg p/1 and 4.34 mg p/1, respectively. The high water transparency coupled with low phosphorus levels in the pelagic zone indicate that the …

Sediment Distribution And Composition On The Shallow Water Carbonate Basin Of The Zanzibar Channel, Yw Shaghude

Tanzania Journal of Science

Sediments of the shallow water carbonate basin in Zanzibar channel were investigated for composition and grain size distribution. The surface sediment composition was dominated by carbonate sands (with CaCO3 > 30%), except in the area adjacent to mainland coastline and a thin lobe which projects from Ruvu River to the middle of the channel. Mean grain size distribution closely resembles that of the carbonate content, where Tidally Dominated Reef Platform Sediments (TDRPS) located east of the Zanzibar channel were characterised by medium to coarse sands and the siliciclastic sediments adjacent to the mainland were characterised by fine sand. The TDRPS are …

Trace Elements Characterization Of The Hydrothermally Deposited Tanzanite And Green Grossular In The Merelani – Lelatema Shear Zone, Northeastern Tanzania, Epj Malisa

Tanzania Journal of Science

Geochemical investigations of trace element contents of different rock samples were determined in the late Proterozoic metamorphic sequences of the Mozambique Belt along the Merelani–Lelatema shear zone, northeastern Tanzania. The area is composed of the following rock types: pelitic and semi-pelitic gneisses, psammitic, hydrothermally altered including carbonate-rich, carbonate-gypsum-rich, and iron-rich rocks, pegmatite dykes and crystalline limestones. Trace element characteristics of the principal rock units in and outside the shear zone have been compiled and studied. With the exception of higher barium contents in pelites, trace element contents in the psammitic and pelitic gneisses show some similarities while in the hydrothermally …

Derivation Of An Expression That Defines The Pulling Forces In Relays With Small Operating Gaps, D. J. Chambega

Tanzania Journal of Engineering and Technology (TJET)

This paper derives an expression that defines magnitude of the pulling force developed in relays with small operating gaps, that is, when the length of the operating gap in between the yoke and the armature is small as compared to the area of the poles at the yoke. To obtain the expression, saturation of the core material is not considered. Results from the expression are then compared with those obtained experimentally. The comparison is found to deliver acceptable accuracy.

Discrete Element Modelling Of The Abrasive Dehulling Process Of Sorghum And Millet, E. L. Lazaro

Tanzania Journal of Engineering and Technology (TJET)

The abrasive dehulling process of sorghum and millet was modelled using a three-dimensional discrete element model. The model was validated by comparison between experimental and simulation results. Good correlation between experimental and simulation results was obtained. Several numerical experiments were also carried out using the developed model to investigate the influence of mill and grain parameters on dehulling of sorghum and millet. The simulated results correlated well with experimental results from literature. The developed model therefore provides a simple and cheap tool, which can be used to study the dehulling process in more detail than, is currently possible using the …

Effect Of Moisture And Loading Orientation On The Mechanical Properties Of Sorghum And Millet, E. L. Lazaro

Tanzania Journal of Engineering and Technology (TJET)

Uniaxial compression properties of sorghum and millet grain at different moisture contents (12–25% dry basis) and at different kernel orientation were investigated. These included: modulus of deformability, maximum compressive force, deformation and toughness at grain break point. Individual grain kernels of two varieties of sorghum, (Dionje and Jumbo) and one variety of pearl millet, (IM) at 12, 15, 20, and 25% moisture content dry basis (mc.db), were quasi-statically loaded using a J.J.universal tensile testing machine to their breaking point. The modulus of deformability, maximum compressive force required to initiate grain rupture and the grain toughness (energy absorbed at break point …

Potential For Use Of Sand In Road Construction In Dar Es Salaam And Coast Regions, Mfinanga A

Tanzania Journal of Engineering and Technology (TJET)

Coarse aggregates for use in road construction in Dar es Salaam and Coast regions are becoming increasingly scarce and expensive while sand, which is cheaper, is readily available in the two regions. This research aimed at evaluating the possibility of using quarry sands in the two regions as a major constituent material in bituminous road pavement layers. First, the use of sand in sand-bitumen bases for low and medium trafficked roads was studied. The study then continued with the preliminary evaluation of the possible use of the sands in hot rolled asphalt mixes. Results show that Mbagala sand can be …

Incorporating E-Commerce Technologies Into Small And Medium Manufacturing Industries In Tanzania, M. A.M. Victor

Tanzania Journal of Engineering and Technology (TJET)

Businesses worldwide are making use of the new opportunities which have been brought up by the developments in Information and Communication Technologies (ICTs), particularly the Internet. Big businesses, especially those multinationals in the developed nations have invested heavily on these technologies and they are reaping their benefits. This paper reports on a study conducted to look at the key issues to be considered in order for small and medium enterprises (SMEs) in Tanzania be able to position themselves technologically in what is termed as E-commerce. Cost and benefits, policy, training and infrastructure issues are looked at in this study.

Sustainable Data Acquisition Methods For Road Maintenance Management In Developing Countries, N. K.M. Mushule

Tanzania Journal of Engineering and Technology (TJET)

Whilst it may be argued that manual methods of pavement data collection are subjective, unsafe, involve high personnel costs and have low repeatability, the initial costs of acquiring automated systems coupled with the technology required to operate and maintain them can be prohibitive for most developing countries. Moreover, automatic measurement of surface distress has proved to be a difficult challenge to instrument designers. In many cases, manual methods are the only ones that can be employed. A research project was carried out to design a sustainable data collection scheme for network level management system for developing countries. A simple procedure …

Properties Of Rice Husk Particle Boards Bonded By A Blend Of Tannin-Cnsl Resin, J. V. Tesha

Tanzania Journal of Engineering and Technology (TJET)

There are vast quantities of agricultural residues available in Tanzania. Rice husk being amongst those residues is reported to have low resistance to alkalis, high silica content, and have short fibres. These factors have made rice husks not attractive raw materials in panels’ production. However, it has been demonstrated that rice husks can be used to develop panel products of low cost and good performance if appropriate indigenous technologies and affordable binders that can bind siliceous materials are used.

This paper provides a summary on the study of the effectiveness of the binding characteristics of a blend of natural adhesive …

Pretreatment Of Robusta Coffee Hulls And Co-Digestion With Cow-Dung For Enhanced Anaerobic Digestion, A. K. Kivaisi

Tanzania Journal of Science

The effect of alkali pre-treatment on anaerobic digestion of Robusta coffee hulls with a lignin content of 29% was studied in batch culture at 55˚C. In order to investigate the effect of cow dung in minimising the effect of coffee-based inhibitory compounds, digestion experiments were performed with blends of pre-treated and non-treated coffee hulls and cow dung with 0,5,10,20,30,50,75 and 100% coffee hulls at a total volatile solids concentration of 1.8g/l fermentation volume. Methane production increased with increase in coffee hulls concentration up to 30% for both substrates. The lowest production was observed at 100% non-treated coffee hulls. Methane production …

Assessment Of Wind Energy Potential For Eletricity Generation In Setchet, Hanang, Tanzania, A. S. Kasasi, R. M. Kainkwa

Tanzania Journal of Science

Tanzania depends heavily on hydropower for her electricity demand and experiences power shortage during the dry seasons. Wind energy is proposed as an alternative source of electricity to the fossil fuel generators during the dry season, the latter are normally used to supplement the shortfall in hydro-electricity generation. Fossil fuel generators produce emissions that are toxic and as such degrade the environment. Wind speed data from a site called Setchet is used to illustrate that the available wind energy can be harvested to generate electricity that can supplement the shortfall of electricity. The windy season, which is from July to …

Morphometrics Of The Pancake Tortoise (Malacochersus Tornieri) In Tanzania, J. Kabigumila

Tanzania Journal of Science

Observations were made of the morphometrics of captive pancake tortoise (Malacochersus tornieri) in June 1995. Carapace length ranges for immature tortoises and adult males and females were 50-115, 123-160 and 129-171 mm respectively. The respective carapace widths were 45-90, 97-130, and 92-129 and 97-130 mm. Carapace height ranges were 15-29, 25-40 and 117-159 mm, respectively, while plastron length ranges were 45-110, 108-150 and 117-159 mm. The relationships between carapace length and width (males: y = 13.763+0.639x; females: y = 17.302+0.639x) and height (males: y=6.851+0.170x, females: y = 17.274+0.170x) were isometric and sexually dimorphic in adults. The relationship between carapace length …

Sexual Dimorphism In The Mandibles Of A Homogenius Black Population Of Tanzania, F. M. Fabian, R. Mpembeni

Tanzania Journal of Science

Mandibles of known age and gender from cadavers of Tanzanian Bantu population were studied to determine if the human mandible could be sexually dimorphic in a homogenous population. All mandibles were measured using electronic two-digit millimetre veneer calliper. All of the male (100%) and 96% of the female mandibles were positively sexed. The present study indicates that the mandible of the Tanzanian Bantu population possesses metric parameters that make it sexually dimorphic. More studies, involving other Tanzanian groups, might reveal racial or ethnic differences based on mandibular morphometrics.

Structural Evolution Of The Kilombero Rift Basin In Central Tanzania, A. H. Mruma

Tanzania Journal of Science

Detailed geological and structural investigations at the northwestern scarp of the Cenozoic Kilombero Rift allow the drawing of its structural evolution and establishment of stress conditions that prevailed at the different deformational episodes at this rift zone. The structure, where the northwestern scarp of the Cenozoic Kilombero Rift System is located, starts by ductile deformation of granitic and gabbroic rock masses leading to the formation gneissic fabric and b-mineral lineation in the rocks. This deformation is of Precambrian age (most probably a Pan African deformation) and its kinematics are characterized by 320˚/20˚ tectonic transport direction (λ1). Later the area was …

Effect Of Cement Production On Vegetation In A Part Of Southwestern Nigeria, A. T. Salami, A. I. Farounbi, J. I. Muoghalu

Tanzania Journal of Science

The impact of cement dust emissions from the factory of West African Portland Cement at Ewekoro in Southwestern Nigeria on the surrounding vegetation was investigated. Sample plots of 20 m x 20 m were established at 1 km intervals from the factory site up to a distance of 10 km intervals from the factory site up to a distance of 10 km in the four cardinal directions. Leaves of common species were randomly selected for chlorophyll content analysis, leaf abundance and leaf area measurement. Woody as well as herbaceous species encountered within the established plots were enumerated, while soil samples …

Mechanistic Studies Of Carbon Steel Corrosion Inhibition By Cashew Nut Shell Liquid, J Y N Philip, J Buchweishaija, L L Mkayula

Tanzania Journal of Science

The inhibition mechanism of the Cashew Nut Shell Liquid (CNSL) on SAE 1008 carbon steel corrosion in CO 2  saturated 3% NaCl solutions has been studied by weight loss, UV/VIS and electrochemical techniques. The phenoxide, R-Ar-O- ions from the CNSL inhibitor were found to be responsible for the reduction of the corrosion rate of the carbon steel. Also, it was observed that the surface charge of the carbon steel electrodes was positive with respect to the solutions containing CNSL inhibitor. It is likely that the mechanism of the CNSL inhibitor adsorption involved the electrostatic attraction between the positively charged metal …

Organochlorine Pesticides In Residues In Waters From The Coastal Area Of Dar Es Salaam And Their Effect On Aquatic Biota, H Mwevura, Oc Othman, Gl Mhehe

Tanzania Journal of Science

Water samples from Msimbazi and Kizinga rivers in Dar es Salaam and from the coastal marine environment receiving waters from these rivers were analyzed for various organochlorine pescticide residues using GC-ECD and GC-MS. p,p'-DDE, p,p'-DDT, dieldrin and γ-HCH were the only organochlorine pesticide residues detected at significantly greater concentrations above the detection limits. There was a marked difference in the frequency of pesticide residue detection during the dry and wet seasons. All the wet season samples and 37.5% of the dry season samples revealed presence of p,p-DDE at concentrations ranging from 0.05 to 0.45 mgl-1 and 0.08 to 0.20 mgl-1 …

Preparation And Characterization Of Activated Carbons From Rice Husks And Shells Of Palm Fruits, Jeg Mdoe, Ll Mkayula

Tanzania Journal of Science

Activated carbons from palm fruit shells (PFS) and rice husks (RH) were prepared using physical and chemical activation processes, respectively. The influence of activation time and temperature (in the case of PFS) and impregnation ratio and carbonization temperature (in the case of RH) on the properties of the resultant carbons were studied. In the case of PFS carbons, there were an increase in adsorption capacity and surface areas with increase in activation time and temperature. The surface area ranged between 292 and 642 m2g-1 at temperature range of between 1000 and 1200 K. In the case of RH carbons, surface …

Spatial-Temporal Changes In Phytoplankton Biomass And Primary Production In Chwaka Bay, Zanzibar, M. N. S. Kyewalyanga

Tanzania Journal of Science

Spatial-temporal variations in phytoplankton primary production (PP) and biomass (B) were studied for a period of about one year, from July 1999 to July 2000. In addition, changes in corresponding environmental variables were examined. Sampling took place at two stations in Chwaka Bay, one located in mangrove areas, Station I, and the other in an open area, Station II. Although there were changes both with location and time, there were no clear seasonal trends. Generally, the phytoplankton biomass and primary production (mg C m-3 h-1) were higher at Station I than at Station II. However, specific production, that is, primary …