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Tanzania Journal of Science

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An Age-Structured Model For Transmission Dynamics Of Malaria With Infected Immigrants And Asymptomatic Carriers, Asha S Kalula, Eunice Mureithi, Theresia Marijani, Isambi Mbalawata Aug 2021

An Age-Structured Model For Transmission Dynamics Of Malaria With Infected Immigrants And Asymptomatic Carriers, Asha S Kalula, Eunice Mureithi, Theresia Marijani, Isambi Mbalawata

Tanzania Journal of Science

Abstract An age-structured (children and adults) model for the transmission dynamics of malaria with asymptomatic carriers and infected immigrants has been analyzed. We first analyze a model without infected immigrants. It shows that the disease-free equilibrium exists and is stable when and unstable for . Also, we compute the sensitivity indices of the basic reproduction number. The basic reproduction number is most sensitive to the mosquito biting rate. Besides, the sensitivity of the basic reproduction number shows that the children's class parameters are more sensitive than those of adults. In the presence of infected immigrants, the model does not admit …


Mathematical Programming Model For The Two-Level Facility Location Problem: The Case Of Tanzanian Emergence Maize Distribution Network For 2004–2010 Maize Data, Said A. Sima Aug 2021

Mathematical Programming Model For The Two-Level Facility Location Problem: The Case Of Tanzanian Emergence Maize Distribution Network For 2004–2010 Maize Data, Said A. Sima

Tanzania Journal of Science

A two-level facility location problem (FLP) has been studied in the transportation network of emergence maize crop in Tanzania. The facility location problem is defined as the optimal location of facilities or resources so as to minimize costs in terms of money, time, distance and risks with the relation to supply and demand points. Distribution network design problems consist of determining the best way to transfer goods from the supply to the demand points by choosing the structure of the network such that the overall cost is minimized. The three layers, namely production centres (PCs), distribution centres (DCs) and customer …


Stocking Density, Growth And Survival Rate Of Post-Settled Juveniles Of Holothuria Scabra (Jaeger 1833) Reared In An Ocean-Based Floating Hapa, Yussuf S Yussuf, Saleh As Yahya Aug 2021

Stocking Density, Growth And Survival Rate Of Post-Settled Juveniles Of Holothuria Scabra (Jaeger 1833) Reared In An Ocean-Based Floating Hapa, Yussuf S Yussuf, Saleh As Yahya

Tanzania Journal of Science

Ocean-based nursery system using floating hapa have proved to be the best option for raising early sandfish juveniles. However, the nursery system can be further improved by providing key information that will support their application. The present study provides information on the effect of stocking density on growth and survival of sandfish juveniles reared in floating hapa (1 x 0.5 x 1 m). Three densities were tested, 100, 200 and 400 early juveniles (5 mm; 0.093 g) per hapa net in a randomized set-up. Initial density of 100 and 200 showed significant higher growth rate and final size (0.082–0.074 g/day; …


Evaluation Of Antibacterial Activities Of Tanzanian Moringa Oleifera Extracts Against Escherichia Coli And Klebsiella Pneumonia Clinical Isolates, Sartaz Begum, Jenipher S. Asenga, Valence M.K. Ndesendo, Baraka L. Ngingo Aug 2021

Evaluation Of Antibacterial Activities Of Tanzanian Moringa Oleifera Extracts Against Escherichia Coli And Klebsiella Pneumonia Clinical Isolates, Sartaz Begum, Jenipher S. Asenga, Valence M.K. Ndesendo, Baraka L. Ngingo

Tanzania Journal of Science

In vitro antibacterial activities of methanolic leaf and seed extracts of Moringa oleifera grown in Dodoma, Tanzania were evaluated using standard microdilution and disc diffusion methods against extended spectrum beta lactamase producing Gram negative bacteria (Escherichia coli and Klebsiella pneumoniae). Microdilution method showed no activity at concentration of 20 mg/mL for all the extracts except leaf extract which exhibited minimum inhibition at concentration of  2.5 µg/mL for E. Coli but when high concentrations of the extracts were used in the disc diffusion method then the results exhibited the highest killing susceptibility at concentration of 0.4 g/mL with zone of inhibition …


Josephson Effect In Mgb2/Pd/Nb Trilayer Josephson Junctions, Anayesu B Malisa Aug 2021

Josephson Effect In Mgb2/Pd/Nb Trilayer Josephson Junctions, Anayesu B Malisa

Tanzania Journal of Science

This paper reports fabrication techniques and results of MgB2/Pd/Nb trilayer Josephson junctions. The MgB2 bottom electrode was co-evaporated by molecular beam epitaxy (MBE) technique from both magnesium and boron sources at a low substrate temperature ~ 300 °C, while the interlayer and the top niobium electrode (Pd/Nb bilayer) were deposited ex-situ using RF sputtering. The junctions exhibited  and  Josephson effect as well as a modulation of the critical current in a magnetic field applied in a direction normal to the junction plane. Fractional and integer Shapiro steps were observed at voltages corresponding to the frequency of the applied microwave radiation …


Mollusc Shells From Neolithic Contexts In The Lake Eyasi Basin, Northern Tanzania, Musa S. Mwitondi, Albert S. Mjandwa, Pastory M. Bushozi Aug 2021

Mollusc Shells From Neolithic Contexts In The Lake Eyasi Basin, Northern Tanzania, Musa S. Mwitondi, Albert S. Mjandwa, Pastory M. Bushozi

Tanzania Journal of Science

The study of the Neolithic period in the Lake Eyasi Basin was dominated by attempts to formulate the area’s chronology, mobility, settlement patterns, subsistence, and cultural capabilities of Neolithic people as attested by domesticated animals, pottery, and lithic artefacts. Occasionally, studies on molluscs were mentioned, but rarely described in detail. Neolithic sites across the Lake Eyasi Basin have yielded remains of both terrestrial (gastropods) and freshwater mollusc shells (mussels). The abundance of mollusc shell remains in the archaeological records of the Lake Eyasi Basin have played a great role in chronological settings, mobility and community integrations, studies of settlement patterns, …


Antimicrobial Activities Of Endophytic Fungal Crude Extracts Isolated From Cashew Tree (Anacardium Occidentale), Nana Amiri, Donatha D Tibuhwa Aug 2021

Antimicrobial Activities Of Endophytic Fungal Crude Extracts Isolated From Cashew Tree (Anacardium Occidentale), Nana Amiri, Donatha D Tibuhwa

Tanzania Journal of Science

This study presents the antimicrobial activities of endophytic fungal crude extracts isolated from leaves, stems and roots of cashew trees (Anacardium occidentale) which showed disease symptoms and those resistant from Fusarium wilt in Mtwara region. Sections of the cashew trees were made and cultured to isolate endophytes. Eight endophytes were isolated and characterized by using morphological and molecular markers. Neopestalotiopsis, Penicillium, Lasidioplodia and Daldinia sp isolated from resistant tree and Auxarthron and Aspergillus sp from diseased tree. Antimicrobial activities of the isolated endophytic fungal crude extracts were done against pathogenic Fusarium oxysporum and three human pathogens namely, Staphylococcus aureus, Escherichia …


Maintenance Automation Architecture And Electrical Equipment Fault Prediction Method In Tanzania Secondary Distribution Networks, Hadija Mbembati, Kwame Ibwe, Baraka Maiseli Aug 2021

Maintenance Automation Architecture And Electrical Equipment Fault Prediction Method In Tanzania Secondary Distribution Networks, Hadija Mbembati, Kwame Ibwe, Baraka Maiseli

Tanzania Journal of Science

Distribution networks remain the most maintenance-intensive parts of power systems. The implementation of maintenance automation and prediction of equipment fault can enhance system reliability while reducing the overall costs. In Tanzania, however, maintenance automation has not been deployed in secondary distribution networks (SDNs). Instead, traditional methods are used for condition prediction and fault identification of power assets (transformers and power lines). These (manual) methods are costly and time-consuming, and may introduce human-related errors. Motivated by these challenges, this work introduces maintenance automation into the network architecture by implementing effective maintenance and fault identification methods. The proposed method adopts machine learning …


Nutritional Composition, Sensory Profile And Consumer Acceptability Of Wheat-Jackfruit Seed Composite Buns, Sarah S Ngwere, Richard J Mongi Aug 2021

Nutritional Composition, Sensory Profile And Consumer Acceptability Of Wheat-Jackfruit Seed Composite Buns, Sarah S Ngwere, Richard J Mongi

Tanzania Journal of Science

Jackfruit seeds flour is very rich in nutrients and may be incorporated into wheat flour to develop nutrient dense baked products. Consumption of these products may improve the nutrition status of the people, hence fulfill sustainable development goal number two. In this study, nutritional composition, sensory profile, and consumer acceptability of wheat-jackfruit seeds composite buns (Mandazi) were investigated. Jackfruit seeds flour (JSF) was developed and incorporated into wheat flour (WF) at 10, 20, and 30% to produce composite flour used for bun preparation. Flours and buns were subjected to proximate, mineral, and sensory analyses with WF serving as a control …


Effects Of Hydroxyurea Treatment On Haemolysis In Patients With Sickle Cell Disease At Muhimbili National Hospital, Tanzania, Azra Gangji, Upendo Masamu, Josephine Mgaya, Joyce Ndunguru, Agnes Jonathan, Irene Kida Minja, Julie Makani, Emmanuel Balandya, Paschal Ruggjao, Siana Nkya Aug 2021

Effects Of Hydroxyurea Treatment On Haemolysis In Patients With Sickle Cell Disease At Muhimbili National Hospital, Tanzania, Azra Gangji, Upendo Masamu, Josephine Mgaya, Joyce Ndunguru, Agnes Jonathan, Irene Kida Minja, Julie Makani, Emmanuel Balandya, Paschal Ruggjao, Siana Nkya

Tanzania Journal of Science

Tanzania is one of the countries with a high burden of sickle cell disease (SCD). Haemolytic anaemia is a clinical feature of SCD, and has been linked to major complications leading to morbidity and mortality. Treatment with hydroxyurea (HU) has shown to induce foetal haemoglobin (HbF) which in turn decreases haemolysis in patients. This study aimed to investigate the effects of HU on haemolysis in SCD patients attending Muhimbili National Hospital, Tanzania by comparing their haemolytic parameters before and after therapy. Patients meeting the criteria were initiated on HU therapy for 3 months. Two haemolytic biomarkers: unconjugated plasma bilirubin levels …


Serological Analyses Of Human Brucellosis In Ngara And Kibondo Districts, Tanzania, Jestina V Katandukila, Yeremia J Chuhila, Fred D Chibwana Aug 2021

Serological Analyses Of Human Brucellosis In Ngara And Kibondo Districts, Tanzania, Jestina V Katandukila, Yeremia J Chuhila, Fred D Chibwana

Tanzania Journal of Science

Brucellosis, a zoonotic disease transmitted by Brucella species, is transmitted to humans from infected animals through handling dairy products like milk, blood, and semen. Although some human communities in Tanzania live close to livestock, the status of human brucellosis in Ngara and Kibondo Districts in Kagera and Kigoma regions, respectively, is poorly understood. As such, the present study aimed to investigate the status of human brucellosis in north-western Tanzania, particularly Ngara and Kibondo Districts, where the risk of contracting zoonotic diseases, including brucellosis, is high due to the abundance of livestock. Among the screened sera (n = 450), the prevalence …


High Speed Hill Climbing Algorithm For Portfolio Optimization, Collether John Aug 2021

High Speed Hill Climbing Algorithm For Portfolio Optimization, Collether John

Tanzania Journal of Science

Portfolio can be defined as a collection of investments. Portfolio optimization usually is about maximizing expected return and/or minimising risk of a portfolio. The mean-variance model makes simplifying assumptions to solve portfolio optimization problem. Presence of realistic constraints leads to a significant different and complex problem. Also, the optimal solution under realistic constraints cannot always be derived from the solution for the frictionless market. The heuristic algorithms are alternative approaches to solve the extended problem. In this research, a heuristic algorithm is presented and improved for higher efficiency and speed. It is a hill climbing algorithm to tackle the extended …


Synthesis Of 1-(2,4-Dinitrophenyl)-3,5-Diphenyl-1h-Pyrazol-4-Ol Via Trans-1,3-Diphenyl-2,3-Epoxy-1-Propanone, Oluwaseyi B Ovonramwen Aug 2021

Synthesis Of 1-(2,4-Dinitrophenyl)-3,5-Diphenyl-1h-Pyrazol-4-Ol Via Trans-1,3-Diphenyl-2,3-Epoxy-1-Propanone, Oluwaseyi B Ovonramwen

Tanzania Journal of Science

The trans-1,3-diphenyl-2,3-epoxy-1-propanone was synthesized from benzaldehyde and 2-bromoacetophenone in 20 min which is more economical. The presence of ethanol and Br in 2-bromoacetophenone facilitated the reaction. The vicinal diaxial coupling constant of trans-1,3-diphenyl-2,3-epoxy-1-propanone was zero, an indication of trans configuration for a rigid 3-membered ring at ~90o dihedral angle. 1-(2,4-Dinitrophenyl)-3,5-diphenyl-1H-pyrazol-4-ol was synthesized from trans-1,3-diphenyl-2,3-epoxy-1-propanone and 2,4-dinitro phenylhydrazine in glacial CH3COOH to give 85.5% yield and characterized using FTIR, 1H, 13C NMR, DEPT 135 and MS spectra. The 1-(2,4-dinitrophenyl)-3,5-diphenyl-1H-pyrazol-4-ol can be exploited for unique biological activities and in the synthesis of synthetic fibers. Keywords:    1-(2,4-dinitrophenyl)-3,5-diphenyl-1H-pyrazol-4-ol, trans-1,3-diphenyl-2,3-epoxy-1-propanone, synthesis, 2,4-dinitro phenylhydrazine.


Effects Of Climate Changes On Water Resources: A Case Of Mindu Dam In Morogoro Municipality, Tanzania, Simon R Melchioly Aug 2021

Effects Of Climate Changes On Water Resources: A Case Of Mindu Dam In Morogoro Municipality, Tanzania, Simon R Melchioly

Tanzania Journal of Science

This paper presents the findings of the research conducted in Morogoro Municipality, central Tanzania. The main objective of the research was to assess the climate change impacts on water resources, taking the Mindu Dam as the case study. The study methodology involved collection, processing and analysis of both primary and secondary data. Data collection involved acquisition of Dam water level data, climate data, and Landsat 8 satellite imagery. Research findings showed that the maximum air temperature increased at a rate of 0.045% on a span of 30 years, while rainfall has been decreasing with time. Also there has been a …


Spatial Modelling For Cholera Incidence Rates In Morogoro Municipality, Tanzania, Caroline Ngereza, Rosalia S. Katapa, Ali R. Mniachi Aug 2021

Spatial Modelling For Cholera Incidence Rates In Morogoro Municipality, Tanzania, Caroline Ngereza, Rosalia S. Katapa, Ali R. Mniachi

Tanzania Journal of Science

Spatial modelling was conducted to examine community factors associated with cholera incidence rates in Morogoro Municipality. The study employed both secondary (cholera cases) and primary (geographic coordinates of community risk factors) data. Spatial lag model was applied in examining association between the variables. All wards of Morogoro Municipality were considered in the study to capture their variations because cholera cases have a tendency to be clustered. Results indicated that market density, distance to the market and distance to the dumpster are significant factors associated with cholera incidence rates in the wards (p < 0.05). Geographically weighted Poisson model was used to show the variations of those factors between the wards in Municipality. A statistically significant positive association of cholera incidence rates; and market density was only found in Mazimbu ward (p < 0.05) and distance from the community to the dumpster was found in Kihonda, Kingolwira, Bigwa, Kichangani, Kilakala and Boma wards (p < 0.001) and some wards at the centre of the municipality which are Mji Mkuu and Kingo (p < 0.05). A statistically significant negative association of cholera incidence rates and distance from the centre of the community to the market was found in Kihonda, Kingolwira and Kichangani (p < 0.001) and Bigwa wards (p < 0.05). Therefore, measures taken to control and prevent cholera disease should base on the variations of the risk factors found in the Municipal wards.  Keywords:    Cholera incidence rate, Spatial lag regression model, Community risk factor, Geographically weighted Poisson model


Physicochemical And Bacteriological Water Quality Parameters In Relation To Land-Use Practices At A Rural Catchment, Mbinga District, Tanzania, Harieth Hellar-Kihampa, Patrick Isdory Ndunguru Aug 2021

Physicochemical And Bacteriological Water Quality Parameters In Relation To Land-Use Practices At A Rural Catchment, Mbinga District, Tanzania, Harieth Hellar-Kihampa, Patrick Isdory Ndunguru

Tanzania Journal of Science

Data on physicochemical water quality parameters and contamination levels is crucial for protection and sustainable utilization of water resources. This study assessed the physicochemical water quality parameters, faecal coliform bacteria and nutrient loads in water at a catchment used for municipal supply in Mbinga District, Tanzania. Samples were seasonally collected from three areas characterized by distinct geographical features, settlement patterns and land-use practices, and analyzed using standard analytical protocols. Data were subjected to paired-sampled t-test and cluster analysis. The parameters varied as follows: pH (4.75–6.83); temperature (16.4–26.2 ºC); electrical conductivity (14.6–121.1 µS/cm); total dissolved solids (7.0–23.2 mg/L); total suspended solids …


Synthesis And Antimicrobial Activities Of 1-((5-Chloro-1-Ethyl-2-Methyl-1h-Imidazol-4-Yl)Sulfonyl)-N-Ethylpyrrolidine-2-Carboxamide, Oluwaseyi B Ovonramwen, Bodunde J Owolabi, Abiodun Falodun Aug 2021

Synthesis And Antimicrobial Activities Of 1-((5-Chloro-1-Ethyl-2-Methyl-1h-Imidazol-4-Yl)Sulfonyl)-N-Ethylpyrrolidine-2-Carboxamide, Oluwaseyi B Ovonramwen, Bodunde J Owolabi, Abiodun Falodun

Tanzania Journal of Science

A new 1-((5-chloro-1-ethyl-2-methyl-1H-imidazol-4-yl)sulfonyl)-N-ethylpyrrolidine-2-carboxamide was synthesized from methyl-1-[(5-chloro-1-ethyl-2-methyl-1H-imidazol-4-yl)sulfonyl]pyrrolidine-2-carboxylate and ethylamine. The compound methyl-1-[(5-chloro-1-ethyl-2-methyl-1H-imidazol-4-yl)sulfonyl]pyrrolidine-2-carboxylate was synthesized from methyl pyrrolidine-2-carboxylate and 5-chloro-4-chlorosulfonyl-1-ethyl-2-methyl-imidazole. The compounds were characterized based on FTIR, 1H, 13C NMR, and DEPT 135 analysis. Antimicrobial activities of the 1-((5-chloro-1-ethyl-2-methyl-1H-imidazol-4-yl)sulfonyl)-N-ethylpyrrolidine-2-carboxamide against Gram-positive (methicillin-susceptible Staphylococcus aureus, methicillin-resistant Staphylococcus aureus, and Bacillus subtilis), Gram-negative (Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae), and Candida albicans were carried out using the standard microbiological method. The newly synthesized 1-((5-chloro-1-ethyl-2-methyl-1H-imidazol-4-yl)sulfonyl)-N-ethylpyrrolidine-2-carboxamide had no activities against the tested organisms. Keywords:    1-((5-chloro-1-ethyl-2-methyl-1H-imidazol-4-yl)sulfonyl)-N-ethylpyrrolidine-2-carboxamide; methyl-1-[(5-chloro-1-ethyl-2-methyl-1H-imidazol-4-yl)sulfonyl]pyrrolidine-2-carboxylate; L-proline; ethylamine.


Assessment Of Groundwater Quality In Areas Surrounding Thundulu Phosphate Mine, Phalombe District, Malawi, Philip Jailos, Peter J. Chimtali, Ephraim Vunain Aug 2021

Assessment Of Groundwater Quality In Areas Surrounding Thundulu Phosphate Mine, Phalombe District, Malawi, Philip Jailos, Peter J. Chimtali, Ephraim Vunain

Tanzania Journal of Science

Water is one of the renewable resources essential for sustaining all forms of life and quality of drinking water is very fundamental for human health. Human activities such as mining act as sources of water contamination which consequently lead to ecological, environmental and health problems. To the best of our knowledge, no study has been conducted around the Thundulu Phosphate Mine to establish the quality of drinking water. In this regard, this study was carried out to evaluate the physico-chemical water quality parameters of areas surrounding the Thundulu Phosphate Mine in Phalombe District. Groundwater samples from the villages surrounding the …


Insecticidal Activities Of Aqueous Extracts Of Five Nigerian Aromatic Spices Against Garden Eggplant Defoliators And Fruit Borer Leucinodes Orbonalis Guenee: Lepidoptera: Crambidae, Juliana A. Ugwu, Kehinde T. Kareem, Julius O. Aluko Aug 2021

Insecticidal Activities Of Aqueous Extracts Of Five Nigerian Aromatic Spices Against Garden Eggplant Defoliators And Fruit Borer Leucinodes Orbonalis Guenee: Lepidoptera: Crambidae, Juliana A. Ugwu, Kehinde T. Kareem, Julius O. Aluko

Tanzania Journal of Science

The study evaluated the prospects of aqueous extracts of five Nigerian spices against garden eggplant defoliators and fruit borer (Leucinodes orbonalis) in the field. The treatments consisted of Piper guineense (black pepper), Aframomum melegueta (aligator pepper), Eugenia aromatica (cloves), Zingiber officinale (ginger), Capsicum annum (chilli pepper) and untreated check (control). All the aqueous extracts evaluated reduced leaf damaged by defoliators on garden eggplant compared to control. P. guineense, with mean value of 11.02 number of perforations, was the most effective against defoliators, followed by E. aromatica (12.97) reducing leaf damage by 39.64 and 28.74%, respectively. However, their efficacies against defoliating …


Potency Of Dioscorea Sansibarensis (Dioscoreaceae) Leaf Eluates On Callosobruchus Chinensis, Linnaeus 1758 (Coleoptera: Bruchidae) In The Protection Of Phaseolus Vulgaris (Fabaceae), Godfrey O. Mauti Aug 2021

Potency Of Dioscorea Sansibarensis (Dioscoreaceae) Leaf Eluates On Callosobruchus Chinensis, Linnaeus 1758 (Coleoptera: Bruchidae) In The Protection Of Phaseolus Vulgaris (Fabaceae), Godfrey O. Mauti

Tanzania Journal of Science

Post-harvest losses of stored Phaseolus vulgaris to the bean weevil Callosobruchus chinensis have reached levels of significant concern. Governments and health organisations propose the discovery of reliable,  healthy and biodegradable pesticides with higher selectivity and a broad spectrum. This study presents investigations on the activities of Dioscorea sansibarensis leaf extracts on the mortality of C. chinensis and reduction of their egg-laying ability. Laboratory experiments under Completely Randomized Design (CRD) were carried out to determine the mortality and anti-oviposition activity of the vacuum liquid chromatography (VLC) eluates of n-hexane (HE), chloroform (CE), ethyl acetate (EE), n-butanol (BE) and methanol (BE) at …


Determination Of Quantile Range Of Optimal Hyperparameters Using Bayesian Estimation, Ayoade I. Adewole, Olusoga A. Fasoranbaku Aug 2021

Determination Of Quantile Range Of Optimal Hyperparameters Using Bayesian Estimation, Ayoade I. Adewole, Olusoga A. Fasoranbaku

Tanzania Journal of Science

Bayesian estimations have the advantages of taking into account the uncertainty of all parameter estimates which allows virtually the use of vague priors. This study focused on determining the quantile range at which optimal hyperparameter of normally distributed data with vague information could be obtained in Bayesian estimation of linear regression models. A Monte Carlo simulation approach was used to generate a sample size of 200 data-set. Observation precisions and posterior precisions were estimated from the regression output to determine the posterior means estimate for each model to derive the new dependent variables. The variances were divided into 10 equal …


Assessment Of Farm Households’ Vulnerability To Desertification In Rural Dry Lands Of Katsina State, Nigeria, Olanrewaju Yusuf Yahaya Aug 2021

Assessment Of Farm Households’ Vulnerability To Desertification In Rural Dry Lands Of Katsina State, Nigeria, Olanrewaju Yusuf Yahaya

Tanzania Journal of Science

The purpose of this study was to use a Vulnerability Index (VI) to assess farm households' vulnerability to desertification in Northern Katsina's dry land ecosystem. The specific objectives were to identify socio-economic characteristics of farm households; and determine the degree of their vulnerability to desertification. A systematic random sampling technique was used to select 633 respondents from 18 rural communities across six Local Government Areas (LGAs). Data from 21 indicators for the three components of vulnerability (exposure, sensitivity and adaptive capacity) were used to measure the degree of vulnerability and thus, classify households into less, moderate and highly vulnerable. The …


Robust Trilateration Based Algorithm For Indoor Positioning Systems, Simeon Pande, Kwame S Ibwe Aug 2021

Robust Trilateration Based Algorithm For Indoor Positioning Systems, Simeon Pande, Kwame S Ibwe

Tanzania Journal of Science

Indoor Positioning Systems (IPS) plays crucial roles in indoor environment items positioning used in self-navigating robots and helping hands. To obtain position information, positioning algorithms employing Received Signal Strength Indicator (RSSI) are of great benefits since they reuse the existing radio wireless infrastructures for indoor positioning. However, the changes in the indoor environment decrease the overall accuracy of the developed indoor positioning algorithms. To cope with the challenge of environmental dependency in indoor positioning, a robust algorithm using radio signal identification was developed. The algorithm uses circle expansion and reduction mechanism to achieve better RSSI-Distance relationship. The distances from RSSI-Distance …


Effect Of Lowering Tube Potential And Increase Iodine Concentration Of Contrast Medium On Radiation Dose And Image Quality In Computed Tomography Pulmonary Angiography Procedure: A Phantom Study, Justin E Ngaile, Peter K Msaki, Evarist M Kahuluda, Furaha M Chuma, Jerome M Mwimanzi, Ahmed M Jusabani Aug 2021

Effect Of Lowering Tube Potential And Increase Iodine Concentration Of Contrast Medium On Radiation Dose And Image Quality In Computed Tomography Pulmonary Angiography Procedure: A Phantom Study, Justin E Ngaile, Peter K Msaki, Evarist M Kahuluda, Furaha M Chuma, Jerome M Mwimanzi, Ahmed M Jusabani

Tanzania Journal of Science

The aim of the study was to examine the effect of lowering tube potential and increase iodine concentration on image quality and radiation dose in computed tomography pulmonary angiography procedure. The pulmonary arteries were simulated by three syringes. The syringes were filled with 1:10 diluted solutions of 300 mg, 350 mg and 370 mg of iodine per millilitre concentration in three water-filled phantoms simulating thin, intermediate and thick patients. The phantoms were scanned at 80 kVp, 110 kVp and 130 kVp and 0.6 second rotation time using a 16 slice computed tomography (CT) scanner. The tube current was either fixed …


Mineral Liberation: A Case Study For Buzwagi Gold Mine, Alphonce Wikedzi, Thomas Leißner Aug 2021

Mineral Liberation: A Case Study For Buzwagi Gold Mine, Alphonce Wikedzi, Thomas Leißner

Tanzania Journal of Science

Buzwagi Gold Mine (BGM) process plant was designed such that, after secondary grinding, gold and copper are recovered by flotation. However, the flotation circuit had been inefficient, and as a result, cyanidation of flotation tailings is currently conducted to improve gold recovery. The inefficient flotation is suspected to be due to mineralogical variations of ores treated. Hence, mineral liberation characteristics of three ore blends treated by BGM were investigated by automated Scanning Electron Microscope (SEM) whereby five fractions (i.e.  -1 +0.5 mm, -0.5 +0.25 mm, -0.25 +0.125 mm, -0.125 +0.063 mm and -0.063 mm) were used. It was found that …


Utilization Of Iron Filings As Partial Replacements For Sand In Self-Compacting Concrete, Simon O. Olawale, Mutiu A. Kareem, Habeeb T. Muritala, Abiola U. Adebanjo, Olusegun O. Alabi, Oluwole A. Olawuyi, Olusola O. Fadipe Aug 2021

Utilization Of Iron Filings As Partial Replacements For Sand In Self-Compacting Concrete, Simon O. Olawale, Mutiu A. Kareem, Habeeb T. Muritala, Abiola U. Adebanjo, Olusegun O. Alabi, Oluwole A. Olawuyi, Olusola O. Fadipe

Tanzania Journal of Science

The use of industrial by-products in concrete production is part of concerted efforts on the reduction of environmental hazards attributed to the mining of conventional aggregates. Consideration of iron filings (IF), a by-product from steel production process, is an environmentally friendly way of its disposal which is expected to yield economic concrete production. Six self-compacting concrete (SCC) mixes were made by partially substituting river sand with IF at 5%, 10%, 15%, and 20% and the mix without IF (0% IF) served as the control. The water-binder (w/b) ratio of 0.45 was adopted for all mixes. The fresh state properties of …


Analysis And Performance Evaluation Of Entropic Thresholding Image Processing Techniques For Electrical Capacitance Tomography Measurement System, Josiah Nombo, Alfred Mwambela, Michael Kisangiri Aug 2021

Analysis And Performance Evaluation Of Entropic Thresholding Image Processing Techniques For Electrical Capacitance Tomography Measurement System, Josiah Nombo, Alfred Mwambela, Michael Kisangiri

Tanzania Journal of Science

To improve image quality generated from the electrical capacitance tomography measurement system, the use of entropic thresholding techniques is investigated in this article. Based on the analysis of the principle of Electrical Capacitance Tomography (ECT) image reconstruction and entropic thresholding, various algorithms have been proposed for easy extraction of quantitative information from tomograms generated from the ECT system. Experiments indicate that proposed algorithms can provide high-quality images at no or minimum computational cost. It is easier to implement and integrate with classical algorithms such as Linear Back Projection, Singular value decomposition, Tikhonov regularization, and Landweber. Entropic thresholding techniques present a …


Local Communities’ Awareness On Payments For Ecosystem Services For Improved Livelihood And Conservation Of Nyando Wetland, Kenya, Joseph K. Maithya, Felix L.M. Ming’Ate, Sammy C. Letema Aug 2021

Local Communities’ Awareness On Payments For Ecosystem Services For Improved Livelihood And Conservation Of Nyando Wetland, Kenya, Joseph K. Maithya, Felix L.M. Ming’Ate, Sammy C. Letema

Tanzania Journal of Science

Nyando wetland provides several ecosystem goods and services, i.e., provisioning, cultural, supporting and regulating which are essential for human well-being for making life possible and worth living. Payment for Ecosystem Services presents one key question in current literature on whether local communities are aware of ecosystem services provided by wetlands. This paper contributes to the understanding of the local community’s level of awareness of the ecosystem services provided by Nyando wetland in Kenya as a strategy to improve protection of wetlands. The study is significant as it proposes policy options that can assist conservation authorities and local communities in management …


Bayesian Hetero-Elasticnet (A Gibbs Sampler Approach), Isiaka Oloyede Aug 2021

Bayesian Hetero-Elasticnet (A Gibbs Sampler Approach), Isiaka Oloyede

Tanzania Journal of Science

Combined heteroscedasticity and multicollinearity as dual non-spherical disturbances were experimented asymptotically. A Gibbs Sampler technique was used to investigate the asymptotic properties of hetero-elasticnet estimator with mean squares error (MSE) and bias as performance metrics. The seed was set to 12345;  is set at ; Xs variables were generated as follow: the design matrix was generated from the multivariate normal distribution with mean > 0 and variance .  and  are truncated with Harvey (1976) heteroscedastic error structure;  are collinear covariate with pairwise correlation between 0.6 and 0.9, the sample sizes were 25, 100 and 1000. The number of replications of the …


Generalizations Of Integral Inequalities Similar To Hardy’S Inequality, Gabriel Nshizirungu, Marco Mpimbo, Vedaste Mutarutinya Aug 2021

Generalizations Of Integral Inequalities Similar To Hardy’S Inequality, Gabriel Nshizirungu, Marco Mpimbo, Vedaste Mutarutinya

Tanzania Journal of Science

In this paper, we established the generalizations of integral inequalities similar to Hardy’s inequality. Keywords:    Hardy’s inequality, Integral inequalities, similar version, Hlder’s inequality, Generalizations.