Mkwawa University College of Education

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Concentrations of Heavy Metals (Zn, Cu, Pb and Cd) in the Selected Edible Fish Species along the Coast of Dar es Salaam, Tanzania
(2008) Fundisha, Evarist
The concentrations of heavy metals in edible fish species were determined to assess their health hazards to fish consumers. Mean concentrations of Zinc (gg-1 dry wt) in liver, kidney, gills and muscles were 121.78, 72.87, 61.66 and 10.30 and 14.13, 8.36, 3.40 and 1.98 for Copper respectively. Cadmium and Lead were below the detection limit (0.01 ㎍ g-1) in muscles but for liver, kidney and gills, the mean values were 0.14, 0.10 and 0.01 gg-1 for Cadmium and 0.03, 0.04 and 0.06 gg-1 for Lead respectively. This indicates that the concentrations of metals in the fish were within permissible levels.
Dependence of Dalbergia melanoxylon Natural Populations on Root Suckers Germination
(Asian Journal of African Studies, 2008-08-24) Washa, Bugalama Washa
Dalbergia melanoxylon (leguminoceae, Papilionoidea) is a small tree that gives small, thin, flattened and indehiscent pods enclosing delicate seeds. It is valuable because it produce the most expensive timber and carvings in the world. This paper disclosed why seed germination and young seedling growth are vulnerable to available water. The in-sity survey indicated the dependence of the species to root suckers germination and that the adult mpingo are water demanding.
Analysis of Transaction Costs in Coffee Cooperatives: A Case of Arumeru District of Tanzania
(2009) Mbise, Mirau
This study assesses the capacity of co-operatives in reducing the transaction costs in Arumeru district, Arusha region. The main objective was to compare transaction costs between users and non users of co-operatives. Descriptive statistics and independent sample t-test were used to analyse the data. When the transaction costs from all aspects were added up and the means compared by using t-statistic, the result showed that transaction costs incurred by members and non-members of co-operatives don’t differ significantly. The study recommends the monitoring and evaluation of policies formulated to insure good performance of coffee production and marketing.
Building Community Resilience to Earthquake Disaster Risk Reduction in Sub-Saharan Africa: A Case of Southwestern Tanzania
(Tanzania UNESCO National Committee, 2009) Hambat, Hebert; Haulle, Evaristo; Rugumamu, William
The Determinants of Interest Rate Spreads in Developing Countries: Evidence on Tanzania, 1991-2009
(2011) Mugizi, Francisco M.P.; Aikaeli, Jehovaness; Ndanshau, Michael O.A.
The now market based financial system in Tanzania is characterized by relatively high interest rate spreads. This paper sought to establish relative importance of macroeconomic and regulatory factors in explaining persistence of interest rate spread in Tanzania during the period 1991:I - 2009:IV. A Cointegration and Error Correction Model (ECM) was used to fit the data for Tanzania. The results revealed the interest rate spreads in Tanzania were strongly influenced by net government borrowing from commercial banks, development of the banking sector, statutory minimum reserve requirement and the discount rate. Among others, the results suggest the importance of low discount rate and reduced or total dispense with reserve requirement as a monetary policy strategy to reduce interest rate spreads in Tanzania. Importance of price stability in financial deepening is also underscored by the results.
CLASSIFICATION OF PLANTS ACCORDING TO THEIR HEAVY METAL CONTENT AROUND NORTH MARA GOLD MINE, TANZANIA: IMPLICATION FOR PHYTOREMEDIATION
(AJOL, 2011) Mganga, Nyatwere; Manoko, Mkabwa; Rulangaranga, Zachariah
Plants like other living organisms respond differently under different environmental conditions. An elevated level of heavy metals is one of the stresses which results into three classes of plants depending on their heavy metal content. The classes of plant species according to their accumulated heavy metals around North Mara Gold Mine were not known. To study such classes, a line transect of 700m long was established opposite the gold mine wastes. A total of eight sampling points were systematically established each after every 100m in that transect. Fifteen plant species were sampled; at least one species per sampling point. Approximately 5g of the root and shoot portions of the plants were separately collected from each plant. Three soil samples were also collected at each sampling point where vegetations were previously sampled. The soils and vegetations were analyzed for heavy metals (copper, lead, chromium, zinc, cadmium and nickel) by AAS. Of 15 plant species; 10, 6, 6 were hyperaccumulators, excluders and indicators for heavy metals respectively. Detailed studies on the agronomical requirements, optimizations, growth rates and the incidence of pests and diseases are required on the identified heavy metal hyperaccumulator plants for possible future remediation of the study area.
Wild Black-lip Pearl Oyster (Pinctada margaritifera) Spat Collection in Tanzania
(2011) Ishengoma, Edson B.; Jiddawi, Narriman S; Tamatamah, Rashid A; Mmochi, Aviti J
Pearl farming is a growing aquaculture activity in Tanzania but requires sufficient young pearl oysters to make it feasible. Collection of spat in the wild is the most viable way of doing this and was tested to establish whether it would yield sufficient juvenile pearl oysters to support an industry. A total of 4263 Pinctada margaritifera spat were collected over a year at sites considered suitable for spat collection: Bweleo and Nyamanzi on Zanzibar, and Tawalani in Northern Tanzania. Spat “yield” exhibited seasonal variations at these sites in a pattern similar in annual trend at Tawalani and Bweleo but different at Nyamanzi. Generally, the dry season (June-November) yielded a higher number of spat than the wet season (December-May). During the dry season, Tawalani, Bweleo and Nyamanzi produced 877, 942 and 1176 P. margaritifera spat respectively, while, during the wet season, these numbers were 503, 730 and 35. A few other pearl oysters such as Pteria penguin were inadvertently collected at Nyamanzi during the study. Three different types of spat collectors were used during the study, comprising coconut shells, spat bags and rubber tiles. There was significant variation in the number of spat collected on these materials (P < 0.01). The yield was always greater on spat bags and rubber tiles than on coconut shells. The study showed that it is possible to collect sufficient numbers of wild spat for the culture of black-lip pearl oysters at some sites along the coast of Tanzania.
Effect of various structure directing agents on the physicochemicalproperties of the silica aerogels prepared at an ambient pressure
(Applied Surface Science, 2011-09-11) Sarawade, Pradip B.; Shao, Godlisten N.; Quang, Dang Viet; Kim, Hee Taik
tWe studied the effects of various surfactants on the textural properties (BET surface area, pore size,and pore volume) of the silica aerogels prepared at an ambient pressure. A simple surface modificationof silica gel prepared at an ambient pressure through hydrolysis and polycondensation of TEOS as asilica precursor was conducted using various structure directing agents. The treatment was found toinduce a significant difference in the porosity of the silica aerogel. Highly porous silica aerogels withbimodal porous structures were prepared by modifying the surface of the silica wet-gel (alcogel) withtrimethylchlorosilane (TMCS) in order to preserve its porosity. The samples were analyzed by small-angleX-ray scattering and nitrogen adsorption. In this work, a possible new type of highly porous hydrophobicsilica aerogel with a bimodal porous structure is presented. A hydrophilic extremely porous (high surfacearea and large pore volume) silica aerogel was obtained by heating the as-synthesized hydrophobicsilica aerogel at 400◦C for 1 h. There was a significant effect of structure directing agent on the texturalproperties, such as specific surface area, pore size distribution and cumulative pore volume of the silicaaerogels.
Effects of forest fragmentation on pollination of Mesogyne insignis (Moraceae) in Amani Nature Reserve forests, Tanzania
(2011-10) Olotu, Moses I.; Ndangalasi, Henry J.; Nyundo, Bruno A.
The efficacy of pollination biology of Mesogyne insignis is poorly known in fragmented forests of Amani Nature Reserve. This study was conducted to determine the effect of forest fragmentation on potential pollinators of this endangered species. Three intact forests and three forest fragments were selected for this study, the intact forests serving as control. Visual observation of insects visiting inflorescences, insect trapping and pollinator exclusion experiments were the methods employed in assessing pollination. Most members of the solitary bee genus Megachile were found to be potential pollinators of M. insignis. Diversity of pollinators was significantly higher in intact forests than in forest fragments. Overall, the total number of fruits set was significantly higher in intact forests than in forest fragments, perhaps a reflection of the higher diversity and abundance of potential pollinators in an intact forest. The pollination system of M. insignis is generalist in terms of systematic group of pollinators, and forest fragmentation may have significant impact on this pollination pattern. A similar study should be conducted in other Eastern Arc Mountains where M. insignis grows to find out whether the potential pollinators are similar or not.
Silver-Doped Silica Powder with Antibacterial Properties
(Powder Technology, 2011-10-08) Hilonga, Askwar; Kim, Jong-gil; Sarawade, Pradip B.; Quang, Dang Viet; Shao, Godlisten N.; Elineema, Gideon; Kim, Hee Taik
In this study a simple and reproduciblemethodwas used to develop silver-doped silica powder with antibacterial properties. Silicamatriceswere synthesized via a sol–gel route which allows one to easily tailor textural and chemical properties. A wide range of silica-materials/products was obtained via the present route. These are: pure silver nanoparticles (Ag0), silver in ionic state (Ag+), AgCl nanoparticles, and the mixture of Ag0 and AgCl. The efficacy of these products were tested against Escherichia coli and the results demonstrate thatmaterials that are suitable for antibacterial applications were obtained by this newly developed technique while utilizing sodium silicate, which is relatively inexpensive, as a silica precursor. This may significantly boost the industrial production of the inexpensive silver-doped silica products for various applications. A project on other innovative industrial applications of our products is in progress.
Effects of forest fragmentation on pollination of Mesogyne insignis (Moraceae) in Amani Nature Reserve forests, Tanzania
(Blackwell Publishing Ltd, 2011-10-17) Olotu, Moses I; Ndangalasi, Henry J; Nyundo, Bruno A
The efficacy of pollination biology of Mesogyne insignis is poorly known in fragmented forests of Amani Nature Reserve. This study was conducted to determine the effect of forest fragmentation on potential pollinators of this endangered species. Three intact forests and three forest fragments were selected for this study, the intact forests serving as control. Visual observation of insects visiting inflorescences, insect trapping and pollinator exclusion experiments were the methods employed in assessing pollination. Most members of the solitary bee genus Megachile were found to be potential pollinators of M. insignis. Diversity of pollinators was significantly higher in intact forests than in forest fragments. Overall, the total number of fruits set was significantly higher in intact forests than in forest fragments, perhaps a reflection of the higher diversity and abundance of potential pollinators in an intact forest. The pollination system of M. insignis is generalist in terms of systematic group of pollinators, and forest fragmentation may have significant impact on this pollination pattern. A similar study should be conducted in other Eastern Arc Mountains where M. insignis grows to find out whether the potential pollinators are similar or not.
Synthesis of Silver Nanoparticles within the Pores of Functionalized-Free Silica Beads: The Effect of Pore Size and Porous Structure
(Materials Letters, 2011-10-29) Quang, Dang Viet; Sarawade, Pradip B.; Hilonga, Askwar; Kim, Jong-gil; Shim, YoungHo; Shao, Godlisten N.; Kim, Hee Taik
Here, we report on the synthesis of silver nanoparticles (Ag-NPs) manipulating the pores of silica beads (SBs) with sizes ranging from 0.5 to 1 mm. Silver ions were occluded inside the pores of SBs and in situ reduced to Ag-NPs using Sodium borohydride (NaBH4). SBs with different average pore diameters from 3.8 to 20 nm were used to assess the effect of their pore sizes and porous structures on the formation of Ag-NPs. Obtained results revealed that the silver amount occluded inside pores increases along with the increase of total pore volume. The particle sizes of the synthesized Ag-NPs mainly distribute from 8 to 15 nm and vary with the pore sizes and porous structure.
Two step synthesis of a mesoporous titania–silica composite from titanium oxychloride and sodium silicate
(Powder Technology, 2011-11-15) Shao, Godlisten N.; Elineema, Gideon; Quang, Dang Viet; Kim, You Na; Shim, YoungHo; Hilonga, Askwar; Kim, Jong-gil; Kim, Hee Taik
Mesoporous titania–silica composite (MTSC) with a large surface area (387 m2/g) and large pore volume was synthesized by a two step condensation sol–gel method. Transparent TiO2 sol was formed at room temperature through condensation and peptization of titanium oxychloride solution using ammonium hydroxide and aqueous nitric acid respectively. Sodium silicate was used as a silica source to form a composite with the preformed TiO2 sol. The physical properties of the composite were examined by Fourier Transform infrared (FTIR), BET surface area, thermogravimetric analysis (TGA), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The nitrogen physisorption behavior of the synthesized composite was compared to that obtained from grafting and one-pot co-condensation methods using the same precursors in the presence of cetyltrimethylammonium bromide (CTAB). It was found that MTSC synthesized under this method possessed large pore sizes and pore volume but its thermal stability was comparatively low. FTIR spectra showed the formation of a Ti\O\Si bond at 940 cm−1 suggesting that titania was incorporated in silica to form a composite. The XRD patterns showed that the major phase of the titania had an anatase phase up to 900 °C but it transforms into rutile when calcined at 1000 °C. Furthermore the EDS studies of the as-synthesized and calcined samples substantiated the formation of titania–silica composites.
Characterization of Calcium-Doped Silica Gel Prepared in an Aqueous Solution
(Resources Processing, 2012-02-20) Quang, Dang Viet; Park, Jin Koo; Kim, Jong-gil; Elineema, Gideon; Shao, Godlisten N.; Lee, Jae Eun; Kim, Hee Taik
In this study, calcium-doped silica was prepared by modifying sodium silicate-based silica gel in an aqueous solution of Ca(OH)2. Silica gels with less than 1 mm in size with different pH values were treated in Ca(OH)2 solution at concentrations ranging from 2 to 20 g/L and aged at 25, 60, and 90°C for 40 min. The BET surface area of the silica gel decreased while its pore size increased considerably after modification in Ca(OH)2 solution. The pH of 5% calcium-doped silica in water ranged from about 8.5 to 10, depending on the pH of silica gel, the aging temperature, and the concentration of the Ca(OH)2. When the concentration of the Ca(OH)2 solution was 20%, needle-like crystals of calcium silicate hydrate formed over the surface of silica gel.
Distribution patterns of plant species around North Mara Gold Mine in Tanzania
(International Academic Journals, 2012-03) Mganga, Nyatwere; Manoko, Mkabwa L.K.M.; Rulangaranga, Zachariah K.R.
Elevated heavy metals are toxic to many plants. There are many known edaphic factors affecting alteration of vegetation patterns. This study aimed to determine the relationship between bioavailable heavy metals and distribution patterns of plant species. Three parallel line transects of 3500 m long and 100 m apart were established opposite the mine wastes. Sampling was done at every 100 m up to 700 m and from the last 500 m. Numbers of plant species were systematically recorded using nested quadrats per transect and soil samples were collected at each point. The soil samples were analyzed for evidence of bioavailable heavy metals (copper, lead, chromium, zinc, cadmium and nickel) using an Atomic Absorption Spectrophotometer. Canonical Correspondence Analysis showed that levels of lead, chromium, cadmium and nickel negatively influenced distribution patterns of the plants. However, the Monte Carlo Permutation test showed that the measured metals did not have a significant influence on distribution patterns of the plants. It is likely that distribution patterns of the plants were also influenced by some other factors that were not currently investigated in this research. In terms of conservation as the main priority, waiting for evidence of the influence of heavy metals to have an obvious and significant effect on plant patterns may mean that an ecosystem has already undergone serious damage.
Improving propagation success of D. Melanoxylon (African blackwood) in Tanzania (I)
(Tanzania Journal of Science, 2012-03-15) Washa, W. B. A.; Nyomora, A. M. S.; Lyaruu, H. V. M.
Dalbergia melanoxylon Guill & Perr is a plant with quality wood in the World and therefore is over harvested for timber while its regeneration capacity is very low. The propagation techniques such as tissue culture or use of mycorrhiza have not been investigated which instigated conduction of this study by investigating the presence of mycorrhiza that might be useful for its regeneration. Some 120kg of soil and 120 roots of D. melanoxylon from Kilwa, Kilosa and Babati were sampled to identify mycorrhiza related with regeneration of the species. Cleaning the tissues was done by soaking the root pieces in 1.79M KOH, and 0.1M Hcl. Staining was done using 0.05% Trypan blue and de-staining in 14:1:1 lactic acid: glycerol: water and mounting on slides for observation. Soil was soaked in water overnight and the mycorrhiza was separated using a stereo microscope at 50X. Separated mycorrhiza were incubated for observation using a compound microscope at 400X. Twenty six (26) ECM resembling Inocybe and Laccaria sp were isolated from the root pieces and 18 VAM resembling Glomus species were isolated from soil. It is recommended that future research should investigate proper inoculum types and time for inoculating the species in nurseries for propagation.
Improving propagation success of D. Melanoxylon (African blackwood) in Tanzania (II): Rooting ability of stem and root cuttings of Dalbergia melanoxylon (African blackwood) in response to rooting media sterilization in Tanzania
(Tanzania Journal of Science, 2012-03-15) Washa, W. B. A.; Nyomora, A. M. S.; Lyaruu, H. V. M.
Dalbergia melanoxylon is a plant with valuable wood in the world and therefore is over harvested for timber while its regeneration is very low. The propagation efforts by techniques such as tissue culture or mycorrhiza have not been investigated which instigated conduction of this study. Soil and cuttings were collected from Kilwa, Kilosa and Babati for rooting test, potting media and soil characterization. The results showed that fresh soil improved rooting characteristics while sterilized soil did not due to the presence of mycorrhiza in fresh soil compared to none in sterilized media. The overall rooting in fresh soil in non-mist propagator was higher, 100% for softwood and 37% for root cuttings while none rooted in the open nursery. The results revealed that there was no significant correlation between rooting and collection sites while cutting type and the soil type used significantly influenced rooting. Softwood cuttings that weighed less than 15g significantly increased rooting at (P < 0.05) compared to cuttings that weighed above 15g. It was recommended to propagate Dalbergia melanoxylon using softwood cuttings placed in a non-mist propagator and using fresh soil infected with mycorrhiza.
Two-step rapid synthesis of mesoporous silica for green tire
(KOREAN JOURNAL OF CHEMICAL ENGINGERING, 2012-04-17) Hilonga, Askwar; Kim, Jong-gil; Sarawade, PB; Quang, DV; Shao, Godlisten N.; Elineema, Gideon; Kim, HT
We report a two-step rapid route of synthesizing inexpensive mesoporous silica using the waste material (hexafluorosilicic acid, H2SiF6) of phosphate fertilizer industry and sodium silicate (Na2O·SiO2). The reaction was performed in a newly innovated manufacturing apparatus. This apparatus produces mesoporous silica with uniform properties through controlled mixing of source materials at predetermined equivalent ratio. The precursors are rapidly mixed within the nozzles to enable uniform control of physical properties of the final product. The obtained mesoporous silica was characterized using N2 physisorption studies, scanning electron microscope (SEM), and EDS. The final product was found to have superior properties that are suitable for green tire (environmentally friendly tire) as inorganic filler. The process reported in this study may significantly reduce the release of hazardous materials into the environment and it might confer economic benefits to the responsible industries. A project on innovative industrial application of our products for the tire industry is in progress.
Synthesis of Mesoporous Silica with Superior Properties Suitable for Green Tire
(2012-04-26) Hilonga, Askwar; Kim, Jong-gil; Sarawade, Pradip B.; Quang, Dang Viet; Shao, Godlisten N.; Elineema, Gideon; Kim, Hee Taik
In this article we report synthesis of mesoporous silica with superior properties for application in green tire (environmentally friendly tire) as filler. The synthesis was done using a newly innovated apparatus which produce mesoporous silica with superior properties. The desired superior properties are big pore size, optimum BET, large pore volume, uniform properties, and improved performance in real application as tire filler. Mesoporous silica was characterized by BET method and final product with a pore diameter of up to 37 nm was obtained without using surfactants. This is unprecedented step toward synthesis of silica that is suitable for tire industry.
BET Study of Silver-Doped Silica Based on an Inexpensive Method
(Materials Letters, 2012-04-28) Hilonga, Askwar; Kim, Jong-gil; Sarawade, Pradip B.; Quang,Dang Viet; Shao, Godlisten N.; Elineema, Gideon; Kim, Hee Taik
The aimof this study is to identify an acid precursor that ismost desirable for the synthesis of sodiumsilicate-based silver-doped silica for large-scale industrial production. The final products were developed based on the presence of silver (silver-doped silica) or the absence of silver (pure silica). The properties of the obtained final products were examined using the BET method. This method involves characterization based on N2 physisorption studies to determine the surface area, pore diameter, and pore volume. Various graphs were plotted using the obtained data to describe the pore size distribution, isotherms, and the properties of hysteresis loops. Silver-doped silica with a BET surface area of up to 357 m2/g and a pore size of 5.4 nm was obtained using the most desirable precursors—sodium silicate and sulfuric acid. This is an unprecedented step toward synthesis of silver-doped silica fromdesirable precursors. This approach to the synthesis of silica with desirable propertieswithout involving sacrificial templates (surfactants) will be convenient for many applications and suitable for large-scale economic industrial production.

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