Open Access. Powered by Scholars. Published by Universities.®

Digital Commons Network™

Open Access. Powered by Scholars. Published by Universities.®

Physical Sciences and Mathematics

Institution
Keyword
Publication Year
Publication
Publication Type
File Type

Articles 301 - 330 of 952

Full-Text Articles in Entire DC Network

Charcoal Whirlwinds And Post-Fire Observations In Serengeti National Park Savannahs, Colin J. Courtney Mustaphi, Heleen C. Vos, Rob Marchant, Colin Beale Jun 2022

Charcoal Whirlwinds And Post-Fire Observations In Serengeti National Park Savannahs, Colin J. Courtney Mustaphi, Heleen C. Vos, Rob Marchant, Colin Beale

Tanzania Journal of Science

Whirlwinds and visible dust devils occur over semi-arid ecosystems and entrain particles from the ground surface. Fires produce abundant charcoal across savannahs and the resulting blackened surfaces create a large albedo contrast. Whirlwinds have been observed associated with active fires; yet, there are few published observations on post-fire landscapes. Spatiotemporal patterns of whirlwinds have been documented for a limited number of regions and have not been made for the ecosystems of eastern Africa. From field-based sightings in the Serengeti National Park, Tanzania, we report on whirlwinds over burned savannah patches that entrained large quantities of charcoal to produce black coloured …

Go to article

Reproductive Potential Of The Mackerel Scad, Decapterus Macarellus (Cuvier, 1833) In The Coastal Waters Of Tanzania, Joseph S Sululu, Blandina R Lugendo, Benaiah L Benno Mar 2022

Reproductive Potential Of The Mackerel Scad, Decapterus Macarellus (Cuvier, 1833) In The Coastal Waters Of Tanzania, Joseph S Sululu, Blandina R Lugendo, Benaiah L Benno

Tanzania Journal of Science

This study investigated the reproductive biology of Decapterus macarellus locally known as ''Msumari", one of the most economically important scad fish along the coastline of Tanzania. Fish samples were collected from ring net artisanal fishers operating in Tanga and Bagamoyo coastal waters, monthly between April 2019 and September 2020. Findings indicated that D. macarellus spawns throughout the year with peaks in August at Tanga and September at Bagamoyo. Overall sex ratios (M: F) were 1:1.03 (Tanga) and 1:1.2 (Bagamoyo) in favour of females. The males and females of D. macarellus at Tanga attained the first maturity at 145.5 mm and …

Go to article

Solar Cells: Types, Modules, And Applications–A Review, Amira Abd-Elfattah Darwish, Rana S. Abdelmohsen, Mohamed Ahmed, M. Megeed Mar 2022

Solar Cells: Types, Modules, And Applications–A Review, Amira Abd-Elfattah Darwish, Rana S. Abdelmohsen, Mohamed Ahmed, M. Megeed

Tanzania Journal of Science

The basic operating principle of photovoltaic (PV) devices is the conversion of solar irradiation into electricity. There are various applications of this principle in many countries such as Egypt, Nigeria and Denmark. Most of the solar PV projects are designed for street lighting, water pumping and water desalination. However, we hope about wide range of using the appropriate components and best technical procedures, standard PV projects with maximum performance output. The present systems now provide 20% to 40% only of the community's heat or lightness on annual basic needs. These include innovative and alternative ways to reduce material uses and …

Go to article

Investigation Of The Vertical Profile Radio Refractivity Gradient And Effective Earth Radius Factor (K-Factor) In Transmission Link Over Oyo, Oyo State, South Western Nigeria, Akeem L. Sheu, Kamaldeen O Suleman, Qasim A Adeniji Mar 2022

Investigation Of The Vertical Profile Radio Refractivity Gradient And Effective Earth Radius Factor (K-Factor) In Transmission Link Over Oyo, Oyo State, South Western Nigeria, Akeem L. Sheu, Kamaldeen O Suleman, Qasim A Adeniji

Tanzania Journal of Science

Surface radio refractive gradient and k-factor are very imperative in observing propagation conditions, designing and planning of microwave communication links in the lower part of the atmospheric boundary layer. The measurement of weather variables (air temperature, atmospheric pressure, relative humidity and wind speed) were conducted in this study at the School of Science, Emmanuel Alayande College of Education, Oyo (7.83°N, 3.95°E), Oyo State, Nigeria. The research was carried out for a period of one year (January to December, 2020) using self-designed cost effective portable weather monitoring systems. The systems were sited from the ground to a height of 200 m …

Go to article

Synthesis Of Polydispersed P(St-Mma-Aa) Microspheres And Fabrication Of Colloidal Crystals With Non-Compact Morphology, Ikhazuagbe H. Ifijen, Eribe M. Jonathan, Jacob N. Jacob, Nyaknno U. Udokpoh, Ukeme D. Archibong Mar 2022

Synthesis Of Polydispersed P(St-Mma-Aa) Microspheres And Fabrication Of Colloidal Crystals With Non-Compact Morphology, Ikhazuagbe H. Ifijen, Eribe M. Jonathan, Jacob N. Jacob, Nyaknno U. Udokpoh, Ukeme D. Archibong

Tanzania Journal of Science

Great attention has been given to the synthesis of monodispersed and uniform colloidal polymer particles with controllable particle sizes. However, investigations on the preparation, characterization and fabrication of polydisperse polymeric particles are very few. Polydisperse polymers are also needed to meet the new demands of the modern markets due to the ease of their synthesis. This study, therefore, synthesized polydispersed poly(styrene-methyl-methacrylate acrylic-acid) (P(St-MMA-AA)) via emulsion polymerization synthetic approach under unstable reaction conditions. The synthesized P(St-MMA-AA) microparticles were characterized using Fourier transform infrared spectroscopy (FTIR), dynamic light scattering (DLS), a thermo-gravimetric analyzer (TGA) and scanning electron microscope (SEM). The DLS results …

Go to article

Boron Doped Zno Films Deposited By Dc Reactive Sputtering Using Zn:B Target: Influence Of The Deposition Temperature On The Structural, Electrical And Optical Properties, Lwitiko P. Mwakyusa, Nuru R. Mlyuka, Margaret E. Samiji Mar 2022

Boron Doped Zno Films Deposited By Dc Reactive Sputtering Using Zn:B Target: Influence Of The Deposition Temperature On The Structural, Electrical And Optical Properties, Lwitiko P. Mwakyusa, Nuru R. Mlyuka, Margaret E. Samiji

Tanzania Journal of Science

ZnO-based transparent and conducting oxides (TCOs) are commonly used as a window layer in thin-film solar cells. However, TCOs with high transparency in the visible and near-infrared parts of the electromagnetic spectrum, plus excellent electrical properties are required in this application. In this study, TCOs based on ZnO:B films deposited by DC reactive sputtering using Zn:B alloy target were investigated. The impact of deposition temperature on the growth and physical properties of the films was examined. Structural, optical and electrical properties of these films were investigated by means of x-ray diffraction (XRD), Ultraviolet-Visible-Near Infrared (UV-VIS-NIR) spectroscopy, and Hall effect measurement, …

Go to article

Assessment Of The Impact Of Climate Change On Stream Flow: The Case Of Little Ruaha Catchment, Rufiji Basin, Tanzania, Joel Nobert Mar 2022

Assessment Of The Impact Of Climate Change On Stream Flow: The Case Of Little Ruaha Catchment, Rufiji Basin, Tanzania, Joel Nobert

Tanzania Journal of Science

Little Ruaha catchment has been recognized for its potential to support multi-projects including irrigated schemes, urban water supply and providing significant inflow to Mtera reservoir for hydropower generation and ultimately Julius Nyerere Hydropower Plant (JNHPP).  Despite the potential, the catchment has experienced declining flows in the recent years. This study assessed the likely changes in streamflow due to future climate change in the Little Ruaha catchment for the period 2025-2060. General Circulation Model (GCM) datasets from ACCESS1.0, CNRM-CM5 and BCC-CSM1 models and RCP4.5 and RCP8.5 greenhouse gas concentration scenarios were selected as the representative scenarios. Impact of climate change on …

Go to article

Mathematical Modelling Of Syphilis Transmission Dynamics: Impacts Of Mass Media Report, Risky Sexual Behavior And Treatment, Gasper G. Mwanga Mar 2022

Mathematical Modelling Of Syphilis Transmission Dynamics: Impacts Of Mass Media Report, Risky Sexual Behavior And Treatment, Gasper G. Mwanga

Tanzania Journal of Science

Syphilis is one of the deadly sexually-transmitted diseases. This paper studied the impacts of sexual behavior, mass media report and treatment of infected individuals on the dynamics of syphilis transmission. The analytical and numerical analyses of the model are presented. The disease free equilibrium of the model is both locally and globally asymptotic stable when the associated reproduction number is less than unity.  Analysis of the Reproduction number shows that it is not possible to control syphilis disease transmission if the rate of individuals practicing risky sexual behavior is high. Furthermore, the treatment of late (latent and tertiary) syphilis infection …

Go to article

Investigation Of The Effects Of Some Statistical Data Components On The Selection Of Optimum Smoothing Constant, Musibaudeen O. Idris, Busayo S. Adeboye, Buliaminu Kareem, Godwin C. Enwerem, Selimot A. Adekanye Mar 2022

Investigation Of The Effects Of Some Statistical Data Components On The Selection Of Optimum Smoothing Constant, Musibaudeen O. Idris, Busayo S. Adeboye, Buliaminu Kareem, Godwin C. Enwerem, Selimot A. Adekanye

Tanzania Journal of Science

Simple exponential smoothing is one of the best forecast methods, especially for time series data. Its efficacy depends on a parameter called smoothing constant (α) which, if optimally determined, minimises the mean square error (MSE), the mean absolute error (MAE) and the mean absolute percentage error (MAPE). The widely used method for selecting the optimum smoothing constant is to conduct a grid search within a wide range of possible values of α using the trial-and-error method. Not only that this method involves the knowledge of advanced statistical processes, but it is also time-consuming, and its results are limited to the …

Go to article

Resource Efficient Advanced Metering Infrastructure Model, Josephina Kimambo, Kwame S Ibwe, Ellen Kalinga, Abdi T. Abdalla Mar 2022

Resource Efficient Advanced Metering Infrastructure Model, Josephina Kimambo, Kwame S Ibwe, Ellen Kalinga, Abdi T. Abdalla

Tanzania Journal of Science

Advanced Metering Infrastructure (AMI) enables two-way communication between smart devices and utility control centers. This involves remote monitoring and control of energy consumption as well as other parameters in the electrical power network in real time. However, increasing technologies in AMI due to huge deployment of smart meters, integration of devices and application of sensors, demand a strong architectural model with the best network topology to guarantee efficient usage of network resources with minimal latency. In this work, a resource efficient multi-hop network architecture is proposed using hybrid media access protocols. The architecture combines queuing and random-access protocol to achieve …

Go to article

Suitability Of Flood Hazard Assessment Methods For Tanzania: A Case Of Little Ruaha And Upper Ngerengere Catchment, Kashimbi J. Kihara, Patrick Valimba, Joel Nobert Mar 2022

Suitability Of Flood Hazard Assessment Methods For Tanzania: A Case Of Little Ruaha And Upper Ngerengere Catchment, Kashimbi J. Kihara, Patrick Valimba, Joel Nobert

Tanzania Journal of Science

Understanding the applicability of flood quantile estimation methods in flood hazard assessment is fundamental for planning, prevention, and management of flood risks. Therefore, this study evaluates and compares three hydrological methods, namely Hydrologiska Byråns Vattenbalansavdelning (HBV), Soil Conservation Service-Curve Number (SCS-CN), and regional regression equation (RRE), to estimate flood quantiles embedded in the existing flood damage assessment framework by applying them to two different river catchments, Little Ruaha (LR) and Upper Ngerengere (UN), Tanzania. The evaluation of method performance was carried out using three standard statistical measures for data from 1954 to 2010 and the 1971–1988 period in LR and …

Go to article

Effects Of Annealing Ambient On The Structural, Optical And Electrical Properties Of Tio2:Ge Thin Films, Lilian A. Owino, Sebastian Waita, Robinson J. Musembi, Francis W Nyongesa Mar 2022

Effects Of Annealing Ambient On The Structural, Optical And Electrical Properties Of Tio2:Ge Thin Films, Lilian A. Owino, Sebastian Waita, Robinson J. Musembi, Francis W Nyongesa

Tanzania Journal of Science

TiO2, a semiconducting material with a wide energy band gap, has been researched intensively due to its interesting properties and many potential applications. The films properties can as well be modified by preparing the films under diverse ambient to suit diverse applications. In this work, the effects of the annealing atmosphere on the structural, optical and electrical properties of pure TiO2 and TiO2:Ge composite thin films deposited by sputtering from commercially available pure TiO2 and TiO2:Ge (85:15) targets respectively were studied. The films were deposited on fluorine doped tin oxide glass substrates by radio frequency magnetron sputtering technique at room …

Go to article

Geochemistry Of Mafic-Intermediate Intrusive Rocks From The Twangiza-Namoya Gold Belt, Eastern Democratic Republic Of Congo: Trace Element Constraints On Their Origin, Petrogenesis And Tectonic Setting, Gerald L. Chuwa, Charles H. Kasanzu Mar 2022

Geochemistry Of Mafic-Intermediate Intrusive Rocks From The Twangiza-Namoya Gold Belt, Eastern Democratic Republic Of Congo: Trace Element Constraints On Their Origin, Petrogenesis And Tectonic Setting, Gerald L. Chuwa, Charles H. Kasanzu

Tanzania Journal of Science

Bulk geochemical data for the Twangiza-Namoya Gold Belt, Democratic Republic of Congo, are presented in order to classify the rock assemblages, elucidate their petrogenesis and tectonic settings. Nb/Yb and Zr/Ti constraints reveal two suites for the rocks: sub-alkaline to andesitic basalts (Suite-1); and alkaline basalts (Suite-2).  Ratios of Ti/Zr = 22–70; Zr/Hf = 35–42; Nb/Ta = 12–13; Nb/Th = 1–2 and La/Nb = 2.4–3.8 suggest arc-generated mantle melts with crustal inputs and arc-fluids metasomatism for Suite-1. The samples have positive LILE and negative Nb, Ta, Ti anomalies, enrichments in the LREE over middle and HREE (La/Yb)CN = 3.6–8.9 with negative …

Go to article

Design And Implementation Of Distributed Identity And Access Management Framework For Internet Of Things (Iot) Enabled Distribution Automation, Ally T Bitebo, Hellen Maziku, Ndyetabura Hamisi, Charles N Tarimo, Kwame S Ibwe, Abdi T. Abdalla Mar 2022

Design And Implementation Of Distributed Identity And Access Management Framework For Internet Of Things (Iot) Enabled Distribution Automation, Ally T Bitebo, Hellen Maziku, Ndyetabura Hamisi, Charles N Tarimo, Kwame S Ibwe, Abdi T. Abdalla

Tanzania Journal of Science

The smart grid and Internet of Things (IoT) technologies play vital roles in improving the quality of services offered in traditional electrical grid. They open a room for the introduction of new services like distribution automation (DA) that has a significant advantage to both utility companies and final consumers. DA integrates sensors, actuators, intelligent electrical devices (IED) and information and communication technologies to monitor and control electrical grid. However, the integration of these technologies poses security threats to the electrical grid like Denial of Service (DoS) attacks, false data injection attacks, and masquerading attacks like system node impersonation that can …

Go to article

Assessment Of Radiation Exposure Levels From Selected Scrap Metal Stores In Dar Es Salaam, Tanzania, Innocent J. Lugendo Mar 2022

Assessment Of Radiation Exposure Levels From Selected Scrap Metal Stores In Dar Es Salaam, Tanzania, Innocent J. Lugendo

Journal of Humanities and Social Sciences

This study analyses the radiation exposure rate emanating from scrap metal stores in Dar es Salaam, Tanzania, using the ion chamber based survey meter and a Gamma-Scout radiation detector. Two (2) scrap metal stores located at Manzese and Ubungo-External were selected for the investigation. The radiation exposure rates in μSv/hr at 20 randomly selected points in each store were determined using a survey meter. More readings were taken at points 100m away from each of the stores to establish the background radiation exposure. From the readings of the survey meter, 3 points with the highest radiation exposure rates from each …

Go to article

Resilient Modulus Of Siliciclastic Unbound Granular Materials Under Repeated Wheel Loading, Siya Rimoyi Feb 2022

Resilient Modulus Of Siliciclastic Unbound Granular Materials Under Repeated Wheel Loading, Siya Rimoyi

Tanzania Journal of Engineering and Technology (TJET)

The Resilient Modulus (Mr) is a fundamental material property input in modern Mechanistic-Empirical (M-E) pavements structural design. Empirical pavement design methods have been in use over a long period during which large databases of four- days-soaked California Bearing Ratio (CBR) values at or near the Maximum Dry Density have been generated in the strength assessments for Unbound Granular Materials (UGMs). In the adoption of the M-E design approach researchers have so far attempted with various degrees of success to develop models to derive resilient modulus from the conventional CBR-based databases. This study provides an extensive laboratory experimental study to investigate …

Go to article

Real-Time Complex Hand Gestures Recognition Based On Multi- Dimensional Features, Isack Bulugu Feb 2022

Real-Time Complex Hand Gestures Recognition Based On Multi- Dimensional Features, Isack Bulugu

Tanzania Journal of Engineering and Technology (TJET)

Gesture recognition is broadly utilized within the field of sensing. There are basically three gesture recognition methods based on computer vision, depth sensor and motion sensor. Motion sensor-based gesture recognition has few input data, fast speed, and direct access to three- dimensional information of the hand. The advantages of traditional motion sensor-based gesture recognition have gradually become a current research hotspot. The essence of traditional motion sensor-based gesture recognition is a pattern recognition problem, and its accuracy depends heavily on the feature dataset extracted from prior experience. Unlike traditional pattern recognition methods, deep learning can be used to a large …

Go to article

Complete Neighbourhood Search Heuristic Algorithm For Portfolio Optimization, Collether John Feb 2022

Complete Neighbourhood Search Heuristic Algorithm For Portfolio Optimization, Collether John

Tanzania Journal of Engineering and Technology (TJET)

In portfolio optimization, the fundamental goal of an investor is to optimally allocate investments between different assets. Mean-variance optimization methods make unrealistic assumptions to solve the problem of optimal allocation. On the other hand, when realistic constraints like holding size and cardinality are introduced it leads to optimal asset allocation which differ from the mean variance optimization. The resulting optimization problem become quite complex as it exhibits multiple local extrema and discontinuities. Heuristic algorithms work well for the complex problem. Therefore, a heuristic algorithm is developed which is based on hill climbing complete (HC-C). It is utilized to solve the …

Go to article

Soil Carbon Accumulation Under Perennial Forage Grasses In The Southern Highlands Of Tanzania, S. S. Nyawira, P. Birthe, M. J. Korir, B. Nzogela, A. O. Notenbaert Feb 2022

Soil Carbon Accumulation Under Perennial Forage Grasses In The Southern Highlands Of Tanzania, S. S. Nyawira, P. Birthe, M. J. Korir, B. Nzogela, A. O. Notenbaert

IGC Proceedings (1977-2023)

Land degradation caused by the loss of SOC in continuously cultivated agricultural systems is a major problem in many sub-Saharan Africa countries. The integration on perennial forage grasses in cropping systems has the potential to enhance SOC sequestration. The main objective of this study is to compare soil organic carbon (SOC) under perennial forages with SOC under annual food crops, specifically maize (Zea mays). A survey was conducted in Njombe district in the Southern Highlands of Tanzania to identity farmers with planted forages that are more than five years old and with neighbouring maize plots. Survey results identified …

Go to article

Optical And Chemical Properties Of Fragaria Ananassa And Galena: Potential Photosensitizers In A Natural Dye-Sensitized Solar Cell, Ibukun S Akinsola, Aderemi B Alabi, Coppede Nicola Dec 2021

Optical And Chemical Properties Of Fragaria Ananassa And Galena: Potential Photosensitizers In A Natural Dye-Sensitized Solar Cell, Ibukun S Akinsola, Aderemi B Alabi, Coppede Nicola

Tanzania Journal of Science

Dye is one of the major components for high power conversion efficiency in a dye-sensitized solar cell. There are challenges natural dyes encounter, especially with quick degradation of the dye molecules. This work considered mineral dye in comparison with plant dye to address the challenge of degradation of natural plant dyes. The optical properties and functional groups of the two natural dyes were studied in this work. The absorption spectra, the optical band gaps and the absorption coefficients of the dyes were reported and found to be suitable for use as photosensitizers in a dye-sensitized solar cell (DSSC), as they …

Go to article

Paleodepositional Environment And Sequence Stratigraphy Of Miocene Sediments In Well Tn-1, Coastal Swamp Depobelt, Niger Delta Basin, Nigeria, Jerry Osokpor, Efetobore G Maju-Oyovwikowhe Dec 2021

Paleodepositional Environment And Sequence Stratigraphy Of Miocene Sediments In Well Tn-1, Coastal Swamp Depobelt, Niger Delta Basin, Nigeria, Jerry Osokpor, Efetobore G Maju-Oyovwikowhe

Tanzania Journal of Science

This research focused on the interpretation of paleodepositional environment and development of a sequence stratigraphic framework for the well TN-1 section, located in the coastal swamp depositional belt of the Niger Delta Basin. Integration of interpreted litho- and biofacies data sets that facilitated the interpretation of the paleodepositional environment enabled the erection of a sequence-stratigraphic framework. Three lithotypes (sand, clay, and shale) distributed within fourteen facies variants were integrated with palynomorph components to delineate five paleodepositional cycles ranging from distal delta plain to bathyal. Eight systems tracts (closely related to depositional cycles, but transcended depositional boundaries in some intervals) that …

Go to article

Rural Electrification Using Iliceto Shield Wire Scheme In Developing Countries: Tanzania Case Study, Heavenlight M Munisi, Santos Kihwele Dec 2021

Rural Electrification Using Iliceto Shield Wire Scheme In Developing Countries: Tanzania Case Study, Heavenlight M Munisi, Santos Kihwele

Tanzania Journal of Science

Rural electrification rate in Tanzania is still very low despite the efforts made by the Rural Energy Agency (REA) in Tanzania. Rural electrification using medium voltage (MV) method has two major obstacles. First obstacle is high cost associated with the cost of extending the grid electricity to rural areas. Second obstacle is remoteness of the villages, which leads to high power loss during transmission. In lieu of economic extension of rural electrification areas, this paper proposes a low cost solution of Iliceto Shield Wire Scheme (ISWS). This technique involves insulating shield wires (SW) from high voltage (132-400 kV) transmission line …

Go to article

Determination Of Cramer-Rao Lower Bound (Crlb) And Minimum Variance Unbiased Estimator Of A Dc Signal In Awgn Using Laplace Transform, Abdi T. Abdalla Dec 2021

Determination Of Cramer-Rao Lower Bound (Crlb) And Minimum Variance Unbiased Estimator Of A Dc Signal In Awgn Using Laplace Transform, Abdi T. Abdalla

Tanzania Journal of Science

This paper presents an alternative approach for the determination of Cramer-Rao Lower Bound (CRLB) and Minimum Variance Unbiased Estimator (MVUE) using Laplace transformation. In this work, a DC signal in Additive White Gaussian Noise (AWGN) was considered. During the investigation, a number of experiments were conducted to analyze different possible outputs under different conditions, and then the patterns of the outcomes were studied. Finally closed-form expressions for the CRLB and MVUE were deduced employing the Laplace transformation. The resulting expressions showed that the proposed method has almost the same number of steps as the existing method. However, the latter requires …

Go to article

Temperature Effects On The Corrosion Inhibition Of Mild Steel In Sulfuric Acid Solution By Acacia Senegal Gum With Halide Ions, Jovine Emmanuel, Joseph Buchweishaija Dec 2021

Temperature Effects On The Corrosion Inhibition Of Mild Steel In Sulfuric Acid Solution By Acacia Senegal Gum With Halide Ions, Jovine Emmanuel, Joseph Buchweishaija

Tanzania Journal of Science

The effects of temperature on the inhibitive effect of naturally occurring Acacia senegal gum exudate on the corrosion of mild steel in sulfuric acid was studied between 35 and 70 °C using electrochemical impedance spectroscopy and potentiodynamic polarization methods. Findings showed that Acacia senegal gum exudate decreases the corrosion rate of mild steel. The inhibition efficiency declined with raising temperature above 35 °C. The increase in the corrosion rate with increasing temperature was observed for both uninhibited and inhibited systems. Addition of halide ions to the Acacia senegal gum exudate solution enhanced the corrosion inhibition efficiency because of synergistic effects, …

Go to article

Physico-Chemical Properties Of Mechanically Extracted Banana Juice At Different Ripening Stages, Mathayo G Mathias, Lilian D Kaale, Oscar Kibazohi Dec 2021

Physico-Chemical Properties Of Mechanically Extracted Banana Juice At Different Ripening Stages, Mathayo G Mathias, Lilian D Kaale, Oscar Kibazohi

Tanzania Journal of Science

This paper presents the findings of a study on physico-chemical properties of low viscosity banana juice from five banana cultivars: Pisang Awak (PSA) an ABB genome, Yangambi km5 (YKM5) an AAA genome and cultivars from AAA-EA genome, namely Mbilabile, Ndeshi and Mlonga. Low viscosity banana juice was extracted using improved mechanical method at five ripening stages. The physico-chemical properties significantly varied according to cultivars and ripening stages (p < 0.05). Yields, total soluble solids (TSS), titratable acidity (TA) and pH were in the range of 19.50–74.03%, 7.33–27.64 ºBrix, 0.37–0.76% malic acid equivalent and 4.09–4.70, respectively. Yields decreased in the order of Mbilabile > Ndeshi > Mlonga > YKM5 > PSA whereas the total soluble solids increased as follows Mlonga < Mbilabile < Ndeshi < YKM5 < PSA. Furthermore, ashes and mineral contents decreased with ripening stages whereas the low viscosity banana juice was rich in potassium and magnesium. Finally, the study recommends stage 5 of the ripeness as ideal for producing low viscosity banana juice. Keywords: Mechanical extraction, Banana cultivar, Ripening stage, Tannin, Banana juice.

Go to article

Atmospheric Instability Conditions During Rainy Seasons Over Tanzania, Pasvolo J Mwinuka, Christian Bs Uiso, Ladslaus B Chang’A, Mwingereza J Kumwenda Dec 2021

Atmospheric Instability Conditions During Rainy Seasons Over Tanzania, Pasvolo J Mwinuka, Christian Bs Uiso, Ladslaus B Chang’A, Mwingereza J Kumwenda

Tanzania Journal of Science

The amount of rainfall and its distribution in time and space is dependent on the atmospheric instability conditions, and on its moisture content. The aim of this study was to determine the atmospheric instability conditions during January to March (JFM), February to April (FMA), March to May (MAM), and October to December (OND) rainy seasons over local climate zones in Tanzania. Zone area average seasonal Convective Available Potential Energy (CAPE), Convective Inhibition (CIN), Precipitable Water (PW) and Lifted index (Li) were calculated and analyzed. Results showed Li < 0 in JFM and FMA over whole Tanzania. During MAM and OND, Li < 0 over the Lake Zone, Western Highlands Zone and Central Zone only. CAPE ranged from 793 J/kg to 1183 J/kg during JFM, and 700 J/kg to 1080 J/kg during FMA. During MAM, CAPE ranged from 170 J/kg to 921 J/kg and from 173 J/kg to 833 J/kg during OND. Results also showed CAPE > 1000 J/kg over the Lake Zone, Western Highlands Zone, Island Zone, and Central …

Go to article

Design And Performance Analysis Of Composite Airfoil Wind Turbine Blade, Hegespo H Mwanyika, Yusufu Ac Jande, Thomas Kivevele Dec 2021

Design And Performance Analysis Of Composite Airfoil Wind Turbine Blade, Hegespo H Mwanyika, Yusufu Ac Jande, Thomas Kivevele

Tanzania Journal of Science

Small horizontal axis wind turbine rotors with composite airfoil rotor blades were designed and investigated in the present study in order to improve its performance in low wind speed and low Reynolds number (Re) conditions for standalone system. The geometrical and aerodynamic nature of a single airfoil small horizontal axis wind turbine blade curtails efficient energy harnessing of the rotor blade. The use of composite airfoil rotor blade improves energy production but imposes uncertainty in determining an optimal design angle of attack and the off design aerodynamic behaviour of the rotor. This research investigated the effects of two airfoils used …

Go to article

Optimal Design Of Hybrid Renewable Energy For Tanzania Rural Communities, Ester T Marcel, Joseph Mutale, Aviti T Mushi Dec 2021

Optimal Design Of Hybrid Renewable Energy For Tanzania Rural Communities, Ester T Marcel, Joseph Mutale, Aviti T Mushi

Tanzania Journal of Science

Rural communities in developing countries lack access to electricity due to high costs of grid extension. This paper proposes a hybrid system of renewable energy (HRES) as solution. The HRES consists of solar, wind, and battery energy storage (BES). The village called Ngw’amkanga in Shinyanga region of Tanzania, East Africa is selected as a case study. An iterative method to determine the size of wind and solar photovoltaic (PV) generation required assuming a project life of 25 years at minimum annualised cost of the system ( ) is proposed. The project life time is fixed on the life span of …

Go to article

Smart Electric Meter Deployment In Tanzania: A Survey, Theresia B Maziku, Kwame S Ibwe, Abdi Abdalla, Ellen A Kalinga Dec 2021

Smart Electric Meter Deployment In Tanzania: A Survey, Theresia B Maziku, Kwame S Ibwe, Abdi Abdalla, Ellen A Kalinga

Tanzania Journal of Science

Using information and communication technologies (ICT) to make the electrical power network intelligent and smarter (smart grid) has been the focal point in transforming electrical power industry. The idea behind smart grid is to transform the Tanzanian power sector into a secure, adaptive, sustainable, and digitally enabled ecosystem that provides reliable and quality energy for all with active participation of stakeholders. Smart metering is a central segment in realizing smart grid. However, a big question is whether Tanzanian power stakeholders are ready for smart metering technology investments for household applications. Operation and maintenance of a smart metering solution is a …

Go to article

Mitigating The Spread Of Measles Under Constrained Health Care Resources In Tanzania Using Social Contact Network Models, Herieth Rwezaura, Seán Mcgarraghy Dec 2021

Mitigating The Spread Of Measles Under Constrained Health Care Resources In Tanzania Using Social Contact Network Models, Herieth Rwezaura, Seán Mcgarraghy

Tanzania Journal of Science

Tanzania revaccinates individuals during measles outbreaks, despite having scant healthcare resources. We construct epidemiological models of measles spread by employing a hybrid of existing social contact networks models to develop SEIR simulation model. Using demographic and measles surveillance data from three rural villages in Tanzania, we simulate the spread of measles and examine which vaccination strategies can effectively control outbreaks. Results strongly indicate the spread of measles largely depends on contact rates among infected individuals within a population. Findings indicate a need for targeted vaccination for children of 6 months to 15 years of age, but equally for unvaccinated older …

Go to article

First Prev Next Last