Digital Commons Network^™

Synthesis Of Template-Free Flower-Like Zno Nanorods Using A Simple Chemical Bath Technique, Benard S. Mwankemwa

Tanzania Journal of Science

Flower-like ZnO nanorods were successfully synthesised using a template-free, low-temperature chemical bath deposition method. The effects of growth time on the structural, morphological, and vibrational properties of flower-like zinc oxide were investigated. X-ray diffraction (XRD) and scanning electron microscopy (SEM) indicated that the crystallite size and density of flower-like ZnO nanorods increased with increasing growth time. Raman spectroscopy confirmed the existence of specific Raman modes that correspond to the wurtzite structure of ZnO. In addition, Raman measurements revealed that increased growth time increases the Raman modes intensity of the flower-like ZnO nanorods. Moreover, the measurements of the Au/ZnO nanorods/FTO Schottky …

A New Extinct Species Of Malagodon (Cyprinodontiformes: Pantanodontidae) From Southeastern Coastal Madagascar, With A Discussion Of Its Phylogenetic Relationships And A Redescription Of The Genus., E. M. Carr, R. P. Martin, J. S. Sparks

School of Natural Resources: Faculty Publications

No abstract provided.

Modelling Prediction Of Cities Real Estate Price Trend Using Recurrent Neural Network: A Case Of Dar Es Salaam City, Ellen Kalinga

Tanzania Journal of Engineering and Technology (TJET)

Real estate refers to a class of real property such as land and its associated infrastructure. The prediction of real estate prices in cities, which is affected by a number of parameters, is an open research problem. The lack of reliable and effective tools for price forecasting in real estate, especially in residential housing, can adversely affect investment flows and the growth of the real estate sector. Taking Tanzania as an example, the price prediction practices rely on human suggestions that are prone to personal bias and subjective to price hysteria for personal gain and impact consumer expectations. To address …

A Computational Study On The Impact Of Anchoring Groups On The Optical And Electronic Properties Of Triphenylamine-Based Dyes For Dye-Sensitized Solar Cell Applications, Geradius Deogratias, Grace Kinunda

Tanzania Journal of Science

Anchoring groups are crucial for enhancing the performance of dye-sensitized solar cells (DSSCs). For instance, cyanoacrylic acid serves as the primary anchoring group in DSSC due to its crucial elements required for effective electron transport. However, it suffers from degradation. To address this limitation, this study proposes alternative cyano-based anchoring groups for sensitizers. Density functional theory (DFT) and time-dependent DFT were used to investigate the optical and electronic properties of the dyes. The studied dyes (excluding the dye containing OH group) displayed three absorption bands within the visible and NIR regions. Low-energy peaks ranged from 498 to 576 nm, corresponding …

Scientific Landscape On Phthalates Biodegradation Research: A Bibliometric And Scientometric Study, Sai Ngassa, Cyprian Mpinda, Kessy F. Kilulya, Rose Masalu

Tanzania Journal of Science

This study investigated the scientific landscape of research on phthalate esters biodegradation using the Web of Science database up to 2022. The collected data were analysed using bibliometric and scientometric tools. A total of 863 scholarly documents published between 1975 and 2022 in 266 journals were selected for analysis. The analysis revealed a growth rate of 6.9% in the research field, with an average document age of 10.8 years. The trend in phthalate biodegradation research showed a steady increase in citations until 1997, followed by a slight decrease until 2005, but experienced renewed interest in 2006 and significant growth in …

Assessment Of Viability Of Coal Mines In Tanzania For Extraction Of Rare Earth Elements, Juma Sija, Mohamed Mazunga

Tanzania Journal of Science

This study aimed at determining the concentrations of rare earth elements (REEs) in coal and coal fly ash (CFA) from three coal mines in Tanzania: Kiwira, Ngaka and Rukwa. The goal was to assess if these resources could be commercially viable for extracting REEs. Coal and CFA samples were analysed using X-ray fluorescence (XRF) spectrometry and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). The total concentrations of REEs in the coal samples ranged from 89.48 parts per million (ppm) to 196.30 ppm, while in CFA samples, ranged from 362.55 ppm to 475.77 ppm. Computed percentage of critical REEs (REYdef, …

Modelling And Forecasting Claim Payments Of Tanzania National Health Insurance Fund, Imani Kapungu, Emmanuel Evarest, Nyimvua Shaban, Andongwisye J. Mwakisisile

Tanzania Journal of Science

The expenses of medical services are increasing across the globe. As a result, pressure is placed on government and insurance companies’ budgets. The amounts of money collected are not enough to cover the claim payments. Therefore, it threatens the sustainability of the health insurance companies due to the mismatch of income and expenditures. This study aimed to model and forecast claim payments for the national health insurance fund (NHIF) in Tanzania. The claim payment data for the period of 2001–2021 from NHIF were used in building the ARIMA model. It was proven that ARIMA (0, 2, 2) is the most …

Phytochemical Constituents Of Cissus Oliveri Growing In Pwani Region, Tanzania, Fadhili S. Estomini, Stephen I. Nnungu, Amelia S. Buriyo

Tanzania Journal of Science

Cissus oliveri (Engl.) Gilg ex Engl. is among the plant species of the family Vitaceae widely used in traditional medicine for management of different ailments. This study aimed at assessing the phytochemicals of C. oliveri parts in order to provide scientific validation for its use as a therapeutic agent. Qualitative analysis of water and ethanolic extracts was conducted by using standard methods and the results revealed that all the parts possess alkaloids, flavonoids, phenols and tannins. Similarly, glycosides and saponins were only present in leaf and root. Quantitative analysis performed by gravimetric and spectrophotometric methods showed that all parts contain …

Impact Of Zn And W Doping Levels On Properties Of Thermochromic Vo2-Based Thin Films, Haji F. Haji, Margaret E. Samiji, Nuru R. Mlyuka

Tanzania Journal of Science

DC magnetron sputtering at a substrate temperature of 425 °C was used to successfully deposit W/Zn-doped VO2 thin films on soda lime glass (SLG) substrates. The aim was to investigate the influence of Zn doping levels on the transition temperature ( ), luminous transmittance (Tlum) and solar transmittance modulation (ΔTsol) of VO2-based thin films. UV/VIS/NIR spectrometer, X-ray Diffraction (XRD), Atomic Force Microscope (AFM), and Rutherford Backscattering Spectroscopy (RBS) were used to characterise the thin films. It was revealed that W/Zn co-doped VO2 thin films with ~ 10.8 at.% Zn showed a luminous transmittance of ~ 40.4%, with excellent solar transmittance …

Digitisation Of Classical Exercise Practices With Stack: Management Of Large Mathematics Classes In Higher Education Institutions, Idrissa S. Amour, Fatuma Simba, Septimi Kitta, Abdi T. Abdalla

Tanzania Journal of Science

Management of large classes’ tutorials is a known problem in Mathematics. Engineering mathematics classes enrol around 1000 students at the University of Dar es Salaam. For effective learning, each tutorial session should register not more than 40 students. This requires at least 25 sessions of tutorials per week, which may not be feasible due to both scarce human resources and venues. In this work, we developed online Mathematics exercises based on the System for Teaching and Assessment using Computer Algebra Kernel (STACK). About 300 STACK questions in linear algebra, calculus, complex numbers, and numerical analysis were constructed for weekly tutorials …

Environment And Sustainability: October 2023, Environment And Sustainability, Office Of The President

Environment and Sustainability Archives

• Replacing diesel with biomass for boiler at AKUH Nairobi,

• Monthly Movie Hour starting from October

• Paper savings from ICT optimisations

• All-vegetarian catering menu

• Zero-waste beach cleanup drive

• Sustainable Events Training

• Launch of 2023 President’s Challenge for Climate Solutions

• And much more…

A Multitask Learning Framework For Pilot Decontamination In 5g Massive Mimo, Crallet Victor

Tanzania Journal of Engineering and Technology (TJET)

Reference signals enable the acquisition of channel state information (CSI) for purposes such as channel estimation, beam selection, precoding, and symbol detection in 5G massive multiple-input multiple output (MAMIMO) systems. Eventually, as more and more users and cells are added, orthogonal reference signals become few which leads to pilot contamination. Pilot contamination limits the performance and occurs when non-orthogonal reference signals occupy time-frequency resources that are alike. Learning-based techniques have been proposed to alleviate it. However, each can only learn to perform a single task namely pilot assignment, power allocation, pilot design, or de-noising for pilot decontamination. In addition, each …

Optical Characterization Of Photocatalytic Tungsten Oxide/Tin Oxide (〖Wo〗_3/〖Sno〗_2) Thin Films For Use In Degradation Of Water Pollutants, Victor Isahi, Christopher Maghanga, Mghendi Mwamburi, Onesmus Munyati, Sylvester Hatwaambo, Emmanuel Akoto, Wycliffe Isoe, Mir Waqas Alam

Tanzania Journal of Science

Organic pollutants in water have been a challenge and pose significant risks to human health. As a result, research efforts to eliminate these pollutants have been on the rise. Photocatalysis has shown incredible potential in water treatment containing organic pollutants since it is affordable and utilizes solar energy. Tin oxide ( ) has ardently been investigated as a photocatalyst for water treatment due to its remarkable properties such as; non-toxicity, and stability. However, its wide band gap and the tendency for some electrons and holes to recombine during its use have been cited to be among limiting factors affecting its …

Hydro-Geochemistry And Related Processes Controlling The Composition Of Thermal Waters In The Lake Natron Basin, Northern Tanzania, Edista A. Abdallah, Charles H. Kasanzu, Crispin P. Kinabo, Akira Imai

Tanzania Journal of Science

Lake Natron Basin (LNB) forms part of the eastern branch of the East African Rift System (EARS) in Tanzania. The basin is endowed with thermal springs flowing towards the lake from the western, northwestern, southwestern and eastern parts. The western, northwestern and south-western thermal springs emanate from fractures in the basaltic rocks while in the east, they originate from the western flank of the Gelai volcano. There are limited studies on these springs, thus their geochemical differences and distributions of physicochemical parameters are not well understood. A hydrogeochemical study was conducted to interpret available geochemical data from the LNB springs, …

Mineralogy And Geochemical Characteristics Of Matamba Kaolin Deposit-Njombe Region South-Western Tanzania: Implications For Industrial Applications, Melania A. Nyimbo, Ronald J. Massawe, Michael M. Msabi

Tanzania Journal of Science

Kaolin is a commercial clay material composed of hydrated aluminosilicate mineral kaolinite and used in various industrial applications such as ceramics, paper, paints, refractories, fiberglass, plastics, cosmetics and pharmaceuticals. It is formed as a result of strong chemical weathering of crystalline and feldspar-rich rocks or hydrothermal alteration of granitic rocks at relatively low temperature and pressure conditions. The kaolin deposit of Matamba originated from the weathering of leucogabbro rock during the development of the African land surface. In view of highlighted properties, the mineralogy and chemical characteristics of the Matamba kaolin deposit were investigated to determine its industrial applications. As …

Design Of A Cooling System Integrated With Ultraviolet Light For Preservation Of Fruits And Vegetables At Variable Tropical Weather Conditions: A Case Study Of Arusha, Tanzania, John Pyuza Gunda, Alexander Pogrebnoi, Baraka Kichonge

Tanzania Journal of Science

Post-harvest losses of fruits and vegetables pose significant challenges, especially in tropical climates. This study introduces the development and performance evaluation of a solar-powered evaporative cooling storage system integrated with ultraviolet light (UV) designed for preservation of perishable fruits and vegetables. The cooling chamber supplied with ultraviolet lamp was developed using locally available materials such as sisal, sponge, and bricks. The performance of the system was evaluated in terms of air temperature decrease, relative humidity increase, and evaporative cooling power capacity both for sunny and cloudy tropical weather conditions. The study reveals that activating the UV light considerably extends the …

Wind Speed Forecasting Using Wavelet Analysis And Recurrent Artificial Neural Networks Based On Local Measurements In Singida Region, Tanzania, Rajabu J. Mangara, Mwingereza J. Kumwenda

Tanzania Journal of Science

High accuracy wind speed forecasting is essential for wind energy harvest and plays a significant role in wind farm management and grid integration. Wind speed is intermittent in nature, which makes the forecasting to be a big challenge. In the present study, three hybrid single-step wind speed forecasting techniques are proposed and tested by local measurement data in Singida region, Tanzania. The three techniques are based on Wavelet Analysis (WA), Back Propagation (BP) optimization algorithm, and Recurrent Neural Network (RNN). They are referred to as WA-RNN, BP-RNN, and WA-BP-RNN. The model results showed that WA-BP-RNN outperforms the other two proposed …

Microplastics In Marine Sediments From Dar Es Salaam Coast: Spatial Distribution And Characterization, Macarius P. Mtega, Matobola J. Mihale, Kessy F. Kilulya

Tanzania Journal of Science

The purpose of the research was to determine the spatial distribution and characterization of microplastics in marine sediments of beaches along the Indian Ocean of Dar es Salaam coast. The sediment samples were extracted in triplicate using floatation method followed by digestion of organic debris, then analyzed using At-FTIR spectrophotometer and stereomicroscope. The mean concentrations of microplastics for Kijichi Beach were 700 ± 907 particles/m2 at 1 cm, 859 ± 839 particles/m2 at 5 cm and 590 ± 782 particles/m2 at 10 cm; from Palm Beach were 157 ± 15 particles/m2 at 1 cm, 130 ± 182 particles/m2 at 5 …

Experimental Measurements Of Ignition Delay Times Of Iso-Octane/N-Butanol Blend Mixtures In Rapid Compression Machine (Rcm), Myeji Materego, Derek Bradley

Tanzania Journal of Science

Among oxygenated alternative fuels, n-butanol is considered as a promising alternative biofuel which can partially (or fully) replace conventional transportation fuels currently in use. However, before n-butanol can be commercially utilised, its fundamental combustion characteristics need to be fully understood. In this work, the effect of adding n-butanol on autoignition property of iso-octane was studied. Measurements of ignition delay times for the two blends of n-butanol proportions of 30% and 50% by mole weight were made in a Rapid Compression Machine for stoichiometric mixtures at 2.0 MPa and temperature range 651-918 K. n-butanol increased ignition delay times of iso-octane at …

An Efficient Derivative Free Iterative Method And Condition Number Of Nonlinear Equations Arising From Real World Phenomena, Alatuhigha Nguni, Chacha S. Chacha, Adeline P. Mtunya

Tanzania Journal of Science

Recent researches have shown a great interest in developing novel numerical methods for solving nonlinear equations of the form  arising from real world phenomena.  However, very little attention has been given to the study of condition numbers which is an important aspect in measuring the sensitivity of the problem in response to slight perturbations in the input data. In this article, we present an efficient free derivative iterative scheme constructed by refining Newton-Raphson method standard form in which the derivative term is approximated by using finite difference scheme; hence making it derivative free. We also conducted an in-depth analysis of …

A Radial Basis Function Neural Network Algorithm For The Simultaneous Retrieval Of Two Meteorological Parameters From Solar Radiation, Nicholas W. Nzala, Nicolausi Ssebiyonga, Dennis Muyimbwa, Taddeo Ssenyonga

Tanzania Journal of Science

Local meteorological parameters are key in understanding the frequency of occurrence of extreme weather conditions such as floods, and droughts, among others. In this study, we present a method for simultaneous retrieval of two weather parameters. The method is based on already measured monthly average values of weather parameters from 2011 to 2016, which were used to train a Feed-forward radial basis function neural network (RBFNN) to obtain a fast and accurate method to compute global solar radiation for specified weather parameters pair. In inverse modelling, a multidimensional unconstrained non-linear optimization was employed to retrieve the weather parameters pair. The …

Evaluation Of The Inhibitive Properties Of Silver Nanoparticles In Senna Occidentalis Root Extract As Corrosion Inhibitor Of Mild Steel, Victor O. Egbeneje, Samuel E. Okhale, Chinyere Imoisi, Isaac O. Ogbogo, Omolade Ojo

Tanzania Journal of Science

The use of nanoparticles as corrosion inhibitors has gained popularity because of its increased corrosion efficiency due to increase surface to volume ratio. Nanoparticles which undergo physisorption/chemisorption to the corrosion metal surface and inhibit the corrosion efficiently also have low toxicity, low cost and easy production. In this research work, weight lost method was applied to study the inhibitive properties of silver nanoparticles (AgNPs) synthesized using Senna occidentalis root extract as environmentally benign corrosion inhibitor of mild steel in 0.5 M H2SO4 medium at 298 K and 308 K. It was observed that the corrosion rate of the steel sample …

Enhancing Service Restoration In Tanzanian Power Grid Using Internet Of Things Sensors And Renewable Energy Sources, Rukia J. Mwifunyi, Daudi C. Mnyanghwalo, Shamte J. Kawambwa

Tanzania Journal of Science

The increased dependence on the electric power grid, coupled with the increasing number of new customers, motivates the need to improve the reliability and resilience of the electric distribution systems. Modern distribution systems are becoming more resilient against power outages due to the increasing integration of Distributed Energy Resources (DERs) and the availability of efficient mechanisms for load shedding. Several studies considered fault detection and Service Restoration (SR) as separate problems without considering the implementation feasibility of integrating both solutions. To ensure the resiliency in the power system, it is important to have proper mechanisms which integrate sensing, detection, and …

Public Perceptions Of Water Quality In The Lake Bunyonyi Sub-Catchment, Western Uganda, Alex Saturday, Thomas J. Lyimo, Siajali Pamba, Susan Kangume, Jeniffer Turyatemba

Tanzania Journal of Science

Lake Bunyonyi ecosystem plays vital roles in water resource conservancy and tourism. Nevertheless, the rapid increase in human population and the unrelenting human activities are threatening the values, functions, and ecological integrity of the lake. In this study, the public perceptions of drinking water quality and its health implications in the Lake Bunyonyi Sub-catchment, Western Uganda are presented. A closed-ended questionnaire was administered to 267 respondents living within one Kilometre away from the lake shores. Besides, observation and interview methods were used to complement data collected by the questionnaire method. Results indicate that the prominent activities around the lake are …

The Effect Of System Quality And User Quality Of Information Technology On Internal Audit Effectiveness In Jordan, And The Moderating Effect Of Management Support, Ahmad Yahiya Ahmad Bani Ahmad (Ayassrah), Anas Ahmad Mahmoud Bani Atta, Hanan Ali Alawawdeh, Nawaf Abdallah Aljundi, Amer Morshed, Saleh Amin Dahbour

Applied Mathematics & Information Sciences

The goal of this study is to ascertain the moderating role that management support has in internal audit effectiveness in Jordan, as well as the impact of system quality and user quality of information technology. There were 172 responders in all, and they were split across Jordanian auditors. In the data analysis process, the quantitative analysis test— which consists of the validity test, reliability test, test of conventional assumptions, and hypothesis test—is applied. Information technology system and user quality are independent variables in this study. The dependent variable in this study is internal audit effectiveness, and the moderating variable is …

Outdoor Performance Of The Black Globe Temperature Sensor On A Hot And Humid Tropical Region, Juan A. Acero, Angela Dissegna, Yon Sun Tan, Adrian Tan, Leslie K. Norford

Research Collection School of Social Sciences

A crucial variable to evaluate thermal comfort is the mean radiant temperature (Tmrt). In this paper we evaluate the performance of the 150 mm black globe thermometer to provide reliable Tmrt values for outdoor settings in Singapore. Accurate Tmrt values are calculated by the method of integral radiation measurements. Based on these, the mean convection coefficient of the black globe has been re-calibrated. Results show an improvement in the estimation of Tmrt with the new coefficient in comparison with the default version suggested in ISO7726:1998. Increasing the averaging periods of the measured variables improved the performance of the derived mean …

On The Use Of Wireless Technologies For Wildlife Monitoring: Wireless Sensor Network Routing Protocols, Lilian Mutalemwa

Tanzania Journal of Engineering and Technology (TJET)

Traditional methods for wildlife monitoring are labor-intensive and time-consuming. Therefore, advanced technologies and remote monitoring methods are becoming increasingly popular. This paper presents a study on wireless technologies for wildlife monitoring. In the study, a review of the literature was done to identify the most commonly used wireless technologies. Various technologies were explored including unmanned aerial vehicles (UAVs), Internet of Things (IoT), wireless sensor networks (WSNs), artificial intelligence (AI), global positioning system (GPS), and very high frequency (VHF) radio. Then, a more detailed study was done on WSN technology. Investigations were done to observe the performance of routing protocols in …

Assessment Of Spatial Variability Of Groundwater Levels In Moroto District, Uganda, Augustina Clara Alexander Dr

Tanzania Journal of Engineering and Technology (TJET)

Globally, the variation of groundwater levels is increasingly overwhelming due to over exploitation resulting from population growth. The dynamic nature of socio-economic activities in Moroto District such as agriculture, settlements and increased trends in irrigation technology has been well-known worldwide as common parameters triggering groundwater variability. Nevertheless, determination of groundwater levels for groundwater management and development purpose is a challenge due to spatial variability in levels across Moroto District. In this study, geostatistical technique in Geographical Information System (GIS) was used to analyze spatial variability of water levels in the study area. The analysis utilized ordinary Kriging method to predict …

Performance Evaluation Of Full Array, Sub-Array And Overlapped Sub-Array Hybrid Beamforming Architectures For Massive Mimo Systems, Godwin Mruma Gadiel

Tanzania Journal of Engineering and Technology (TJET)

The technological advancement in wireless communication, promises high data rate for end users. This has led to the possibility of smart cities, inter connected vehicles, and virtual reality applications. One of the recent technologies in wireless communication is massive MIMO where large number of antennas are deployed at the transmitter or receiver. This is possible due to the use of mmWave in wireless communication. With massive MIMO, beamforming technique can be employed in the communication system. Beamforming is the ability of communication system to direct power to the intended users and to cancel power at non-intended users and thus significantly …

Product Costing And Pricing In Small And Medium Enterprises In Tanzania, Cosmas F Kindole

Tanzania Journal of Engineering and Technology (TJET)

metalwork small and medium enterprises located in Dar es Salaam with the aim of establishing methods used by SMEs in Tanzania in setting selling prices of their products. The study was necessitated by the apparent discrepancy of prices for similar products from SMEs. The approach used to gather information was mainly through direct interview and the use of questionnaires. Direct observation and literature review were also used to establish the whole costing and pricing practices in metal manufacturing SMEs. The findings of the study established that product selling practices of the surveyed SMEs were based on instinct and appearance of …