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Effects Of Bending And Re-Bending On Mechanical Properties Of Locally-Manufactured Steel Rebars, Patrick W. Waruhiu, Simon I. Marandu, Mussa I. Mgwatu Apr 2024

Effects Of Bending And Re-Bending On Mechanical Properties Of Locally-Manufactured Steel Rebars, Patrick W. Waruhiu, Simon I. Marandu, Mussa I. Mgwatu

Tanzania Journal of Science

Steel rebars experience deformation when subjected to bending and re-bending operations. Subsequently, their microstructures are impaired thus affecting the mechanical properties and leading to failure. This study establishes the effects of bending and re-bending the steel rebars on the mechanical properties. Experiments were conducted to determine the effects of bending and re-bending of the steel rebars. Testing was conducted on Ten virgin and Thirty specimens which were bent and re-bent at 45º, 90º, and 180º, and followed by tensile tests. Yield strength, ultimate tensile strength, elongation, and ultimate tensile strength to yield strength ratio (Rm/Re), were recorded. Results showed the …


Assessing The Performance Of Jatropha Curcas And Moringa Oleifera Conditioners Towards Improving Fecal Sludge Treatment For Agricultural Purpose, Doglas Benjamin1 Mar 2024

Assessing The Performance Of Jatropha Curcas And Moringa Oleifera Conditioners Towards Improving Fecal Sludge Treatment For Agricultural Purpose, Doglas Benjamin1

Tanzania Journal of Engineering and Technology (TJET)

been proposed as alternative solutions to replace chemical conditioners for fecal sludge (FS) treatment. However, their effectiveness in treating FS for safe agricultural use has not been thoroughly evaluated. The aim of this study was to assess the suitability of FS treated with Moringa oleifera and Jatropha Curcas conditioners for agricultural use. Physicochemical parameters Indexes, salinity and sodium hazard levels (Wilcox Diagram analysis), and removal efficiency of nutrients and pathogens were evaluated. Qualitative experiments were conducted using dewatering treatment chambers containing untreated control FS samples, FS treated with Moringa oleifera and Jatropha Curcas conditioners at the University of Dar es …


Absorbance Enhancement Of A Treated Tanzanian Kaolin For Removal Of Synthetic Dyes From Water, Samwel Paul Mziray Feb 2024

Absorbance Enhancement Of A Treated Tanzanian Kaolin For Removal Of Synthetic Dyes From Water, Samwel Paul Mziray

Tanzania Journal of Engineering and Technology (TJET)

The absorbance efficiency of local kaolin clay from Tanzania (Pugu kaolin) has been enhanced to improve its utilization in removal of textile dyes from water. The clay was acid-activated using H2SO4, after calcination at 750oC. Characterization by XRF, XRD, ATR-FTIR and Porosimeter showed kaolinite [Al2Si2O5(OH)4], silica (SiO2) and microcline [KAlSi3O8] as the main phases. Upon acid treatment, silica increased from 44.18% to 58.81% due to the appearance of tridymite, and alumina decreased from 26.70% to 12.74% due to disappearance of the kaolinite. Surface area increased from 15.36 to 149.61 m2/g due to removal of acid-soluble impurities. The chemical composition showed …


Reliability Improvement In The Traction System Of Tanzania Standard Gauge Railway, Yusufu Katuga Feb 2024

Reliability Improvement In The Traction System Of Tanzania Standard Gauge Railway, Yusufu Katuga

Tanzania Journal of Engineering and Technology (TJET)

In recent years, many African governments have been developing Standard Gauge Railway (SGR) to replace the old after becoming absolute, inefficient Meter Gauge System (MGR) to carry more loads at high mileage and speed while combating the oil and environmental crises. With the increase of SGR, the amount of traction systems has grown sharply, the service life of the traction system has increased gradually, and the components of the vehicle traction system have become worn and aged as a result. While Tanzania is transitioning to SGR with its gradually increasing traction systems, reliability improvement becomes a key for the sustainability …


Sustainability Of Simplified Sewer Systems: A Case Study Of Vingunguti Urban Settlement, Dar Es Salaam Region In Tanzania, Neema Kijazi Feb 2024

Sustainability Of Simplified Sewer Systems: A Case Study Of Vingunguti Urban Settlement, Dar Es Salaam Region In Tanzania, Neema Kijazi

Tanzania Journal of Engineering and Technology (TJET)

The universal access to safely managed sanitation remains one of the challenges to achieving the UN SDG target 6.2 in unplanned urban settlements including the Vingunguti area in Dar es Salaam City which is high-density populated. In an attempt to address this challenge, a simplified sewer system was piloted as an option for achieving safely managed sanitation in this particular area. The objective of this study was to assess the sustainability of the piloted simplified sewer system for its potentiality to up-scale and replication in areas with similar sanitation challenges in the country. Methodology involved collection of data on performance …


Evaluation Of Environmental Management System For Small And Medium Enterprises In Dar Es Salaam, Tanzania, Juma M. Matindana Feb 2024

Evaluation Of Environmental Management System For Small And Medium Enterprises In Dar Es Salaam, Tanzania, Juma M. Matindana

Tanzania Journal of Engineering and Technology (TJET)

A system that manages environmental issues of Small and Medium Enterprises (SMEs) from the time of acquisition of raw materials up to disposal of the product is not well clear, especially in Tanzania. Most of the studies have been conducted in the field of environment management but few of them address the evaluation of the management of SMEs activities with respect to the environment. Although the nature of activities of SMEs has little noticeable environmental implications at the individual level but the impact is large due to diversification and labour intensity of these SMEs. SMEs employ about 20% of the …


A Two-Stage Based Life Cycle And Principal Component Analysis For Decision Support Of Potential Municipal Solid Wastes Management Scenarios, Case Study Dar Es Salaam, Tanzania, Edwin Richard Ndibalema Dr Feb 2024

A Two-Stage Based Life Cycle And Principal Component Analysis For Decision Support Of Potential Municipal Solid Wastes Management Scenarios, Case Study Dar Es Salaam, Tanzania, Edwin Richard Ndibalema Dr

Tanzania Journal of Engineering and Technology (TJET)

In most of the urban areas of Tanzania, poor and inadequate solid waste management is a growing environmental and public health concern. Despite an array of solid waste management options, choosing an appropriate one remains a challenge. This study applied a novel two-stage-based approach to assess the environmental impacts and sustainability performance of the 27 scenarios for municipal solid wastes (MSW) management of Dar es Salaam City, Tanzania. In the first stage, the study utilized a life cycle analysis (LCA) to quantify the environmental impacts of MSW scenarios. In the second stage, the study used the principal component analysis (PCA) …


An Overview Of Maternity Healthcare Monitoring In Developing Nations, Godphrey Kyambille Feb 2024

An Overview Of Maternity Healthcare Monitoring In Developing Nations, Godphrey Kyambille

Tanzania Journal of Engineering and Technology (TJET)

A healthcare monitoring arrangement is essential for frequently monitoring a patient's health status. Specifically, maternal healthcare systems for tracking are utilized to evaluate the clinical status and monitor any abnormal condition changes during all three trimesters. This paper's objective is to conduct an extensive literature review and acknowledge earlier initiatives and studies conducted previously in maternal health care monitoring. This review focuses on accumulating information from earlier work and presents a general overview of previous studies concerning maternal health care monitoring (MHCM). The paper focuses on the maternal healthcare systems in developing countries accessed by pregnant women during the antenatal …


Augmented Finite Control Set Mpc Design Technique For Wide Speed Range Control Of Permanent Magnet Synchronous Motor Drives, Francis Mwasilu Feb 2024

Augmented Finite Control Set Mpc Design Technique For Wide Speed Range Control Of Permanent Magnet Synchronous Motor Drives, Francis Mwasilu

Tanzania Journal of Engineering and Technology (TJET)

The effective motion control task is highly influencing the final drive performance in wide-range motor drives applications such as electric vehicles (EVs), washing machines, compressors, elevators and lathe machines. Recently, permanent magnet synchronous motor (PMSM) drive has been widely employed in these applications to achieve desired performances such as high efficiency, high torque requirements with minimum size “occupancy”. The PMSM drive features combining with these modern drive applications are highly nonlinear and the desired operation requirements demand high-performance control schemes with fast system response and robustness features. Linear control schemes are usually implemented to drive the PMSM that entail trade …


Cost Estimation Proxy Models For Economic Evaluations In Petroleum Projects: A Case Study From The Onshore Gas Field In The Southern Coastal Tanzania Basin, Fulmence Kaborogo Feb 2024

Cost Estimation Proxy Models For Economic Evaluations In Petroleum Projects: A Case Study From The Onshore Gas Field In The Southern Coastal Tanzania Basin, Fulmence Kaborogo

Tanzania Journal of Engineering and Technology (TJET)

Petroleum economic evaluation involves estimating revenues from forecasted production profiles and field costs including capital expenditures (CAPEX), drilling expenses (DRILLEX), and operating expenses (OPEX). The existing cost-estimating tool requires several inputs making it time-intensive and difficult to use with few data during the early stages of projects. Majority of the previously developed time saving cost estimations proxy models rely on unrealistic assumptions that include uniform operational costs for different fields with a different number of wells, casings, and drilled depths. This work focused at developing proxy models that consider the variability of the development costs with different parameters. The developed …


Systemization & Survival -- “Houston, We Have A Problem” – Business Lessons From Apollo 13, Judith Jacob Iddy, Njeru Zakayo Feb 2024

Systemization & Survival -- “Houston, We Have A Problem” – Business Lessons From Apollo 13, Judith Jacob Iddy, Njeru Zakayo

Markets, Globalization & Development Review

In the business world, there are different factors that determine whether a business will survive or not. Apollo 13 film perfectly demonstrates what every business undergoes throughout its lifecycle. Apollo 13 spacecraft started its journey to the moon successfully with the mission being to land on the moon. Unfortunately, within a very short period of time, Apollo 13 started to experience a series of problems that required quick actions and decisions to be made with the involvement of different sets of technical skills. Ultimately, by using the prototype and systems which NASA had established for Apollo 13, the teams managed …


Preparation Of 2d Tungsten Diselenide (Wse2) Thin Films By Selenization Of Dc-Sputtered W Precursors, Lwitiko P. Mwakyusa Jan 2024

Preparation Of 2d Tungsten Diselenide (Wse2) Thin Films By Selenization Of Dc-Sputtered W Precursors, Lwitiko P. Mwakyusa

Tanzania Journal of Science

Two-dimensional layered transition metal dichalcogenides based on WSe2 films demonstrated promising properties for nano-electronics and photovoltaic applications. In this work, WSe2 films were prepared by selenization of DC-sputtered W precursors. The influence of the selenization temperature on the structural, morphology, and optical properties of the WSe2 films was investigated. The selenization temperature was varied from 350 °C to 450 °C at the interval of 50 °C. Structural, morphology and optical properties of the WSe2 were investigated using X-ray diffractometry (XRD), Atomic Force Microscope (AFM), and UV-VIS-NIR spectrophotometer, respectively. XRD analysis revealed that all WSe2 were polycrystalline and exhibited the co-existence …


Impact Of Traffic Congestion On Transportation System: Challenges And Remediations - A Review, Hamdy B. Faheem, Amira M. El Shorbagy, Mohamed Elsayed Gabr Jan 2024

Impact Of Traffic Congestion On Transportation System: Challenges And Remediations - A Review, Hamdy B. Faheem, Amira M. El Shorbagy, Mohamed Elsayed Gabr

Mansoura Engineering Journal

Traffic congestion is a growing problem in urban transportation networks around the world, having major consequences for the economy and the environment. As metropolitan populations rise and more people rely on autos for mobility, traffic congestion is becoming more common and severe. This review paper presents an overview of the economic and environmental issues caused by traffic congestion in urban areas, as well as proposed ways to reduce its negative effects. It discusses potential traditional transportation solutions such as traffic management infrastructure development, improving public transportation, and intelligent transportation solutions to address traffic congestion problems such as smart parking systems, …


A Method For Investigation Of Small-Scale Morphologic Change Around Low Crested Oyster-Based Structures, Makaya S. Malila Jan 2024

A Method For Investigation Of Small-Scale Morphologic Change Around Low Crested Oyster-Based Structures, Makaya S. Malila

UNF Graduate Theses and Dissertations

In recent years, a novel method for shoreline stabilization, Pervious Oyster Shell Habitat (POSH) units, comprised of recycled eastern oyster shells, has been developed. These mound-shaped structures have been deployed along several shoreline sites in Northeast Florida. This case study sought to develop and implement a method for investigation of small-scale morphologic change in the vicinity of these structures using smartphone LiDAR technology, surveying instruments, and 2D/3D mapping software. Results suggest that the POSH units are helping to mitigate erosion by trapping sediments around them. Moving forward, it may be possible to adapt the methodology used here to assess morphologic …


Ambient Air Emission Profiles Of Polycyclic Aromatic Hydrocarbons Around A Typical University Power House In Nigeria, Oyetunji Okedere Nov 2023

Ambient Air Emission Profiles Of Polycyclic Aromatic Hydrocarbons Around A Typical University Power House In Nigeria, Oyetunji Okedere

Tanzania Journal of Engineering and Technology (TJET)

The level of electricity generation in Nigeria is presently grossly inadequate. Consequently, the productive sectors of the economy do not presently enjoy an uninterrupted supply of electrical energy from the country’s national grid and the downtime is in most cases too much. Using diesel-fueled electric power generators has become an attractive alternative to meet the shortfall in the energy supply gap. In this study, the levels of polycyclic aromatic hydrocarbons in the vicinity of the diesel-fueled electric power generators operated by Osun State University, Osogbo, Nigeria were investigated with a view to ascertain the priority levels and carcinogenic PAHs. Since …


Employment Of Intelligent Predictive Maintenance On Thermal Power Plant Component Parts Taking Condenser Vacuum As A Case Study, Titus Ajewole Nov 2023

Employment Of Intelligent Predictive Maintenance On Thermal Power Plant Component Parts Taking Condenser Vacuum As A Case Study, Titus Ajewole

Tanzania Journal of Engineering and Technology (TJET)

This work proposes deployment of machine learning in the maintenance of individual constituent parts of steam power plant assemblages. With the condenser vacuum of a steam turbine (in a six-turbine plant assemblage) taken as a case study, information on the past operating parameters of the selected plant component was used to forecast its future working condition. Based on Exponential Gaussian Process of Regression, a model was developed, trained using the diachronic operational data, and employed in determining the future. A quantitative evaluation was employed to provide the distribution of the test values of the data about the lines of regression, …


Hydrological System And Water Balance Of Ungauged Crater Lakes Of The Northern Crater Highlands, Godwin Lucas Nov 2023

Hydrological System And Water Balance Of Ungauged Crater Lakes Of The Northern Crater Highlands, Godwin Lucas

Tanzania Journal of Engineering and Technology (TJET)

The study aimed to unveil the hydrological system and water balance of the ungauged crater lakes with major focus on the Emakati Lake which occupy 46% of the Empakaai Crater associated to the East African Rift Valley and form part of the Northern Crater Highlands. Water samples for analysis of NO3- , Cl- and stable isotopes (2H and 18O) were collected from the Emakat lake, springs of the inner, outer and the foot of the Empakaai Crater rims. A combination of satellite data such as digital elevation model (DEM), Climate Hazards Group Infrared Precipitation with Station data (CHIRPS), net shortwave …


Impact Of Zn And W Doping Levels On Properties Of Thermochromic Vo2-Based Thin Films, Haji F. Haji, Margaret E. Samiji, Nuru R. Mlyuka Oct 2023

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 …


Aquaculture In Hydropower Reservoirs, Racheal Macharia Sep 2023

Aquaculture In Hydropower Reservoirs, Racheal Macharia

Tanzania Journal of Engineering and Technology (TJET)

There is an undoubtedly existing relationship between water, energy, and food and their interaction with the natural environment and mankind. Climate change is the talk of the day in global development discussions as it intensifies water shortages, energy, poverty, food shortages, and environmental degradation. Currently, most of the hydropower dams constructed in Africa are majorly built to store water for agricultural purposes, control flooding, and generate electricity. Notable projects include the seven forks hydropower stations located on the Tana River in Kenya; Aswan high dam in Egypt; Grand Renaissance dam in Ethiopia; Kariba dam in Zimbabwe and Akosombo in Ghana. …


Designing A Model Of Solar Photovoltaic Water Pumping System For Off-Grid Localities In Tanzania, Imani Mruma Sep 2023

Designing A Model Of Solar Photovoltaic Water Pumping System For Off-Grid Localities In Tanzania, Imani Mruma

Tanzania Journal of Engineering and Technology (TJET)

Modeling of photovoltaic (PV) water pumping system for rural water localities is vital especially in these modern days, in Tanzania. This is due to the rise of high number of solar-powered rural water projects constructed lacking appropriate design. The fate result into poor and substandard projects delivering below expectations. Kikombo Solar Water Project situated in Dodoma; Tanzania is one among poorly designed solar project chosen as a case study to validate proposed model. The main problem of Kikombo project is unsatisfactory amount of water from domestic points to satisfy population demand. This matter has been raised by pumping-station attendants and …


Mppt Dc-Dc Buck-Boost Converter For Off Grid Hybrid Solar-Wind Battery System In Ikuza Island, Tanzania, Aviti Thadei Mushi Sep 2023

Mppt Dc-Dc Buck-Boost Converter For Off Grid Hybrid Solar-Wind Battery System In Ikuza Island, Tanzania, Aviti Thadei Mushi

Tanzania Journal of Engineering and Technology (TJET)

Ikuza Island in Kagera-Tanzania faces lack of electricity due to cost challenges of extending the grid by marine cables and other transmission facilities. These makes such endeavour not appealing to the supply authority due to those higher charges. Therefore, this paper undertakes to design hybrid renewable energy sources for the island by specifically focusing on the buck-boost converter for the energy conversion from these renewable resources. The design of the bidirectional buck-boost converter for maximum power point tracking in off-grid hybrid renewable energy systems is multifaceted due to the inhomogeneity nature of the renewable energy sources. The bidirectional buck-boost converter, …


Assessment Of Spatial Variability Of Groundwater Potential Using Remote Sensing And Gis-Based-Criteria Evaluation For Dar Es Salaam, Tanzania, Augustina Alexander Sep 2023

Assessment Of Spatial Variability Of Groundwater Potential Using Remote Sensing And Gis-Based-Criteria Evaluation For Dar Es Salaam, Tanzania, Augustina Alexander

Tanzania Journal of Engineering and Technology (TJET)

Groundwater is an important resource for the continuous provision of water supply in both urban and rural areas. Lack of enough knowledge about the spatial variability of groundwater potential zones (GWPZS) has a negative impact on groundwater extraction development and management and may result into over exploitation. In this study, analytic hierarchy approach (AHP)-coupled with multi criteria decision analysis (MCDA) and GIS techniques were employed to integrate hydrogeological, geological as well as topographical data to assess spatial variability of groundwater potential zones of Dar es Salaam city. Seven thematic layers such as lithology, slope, land-use, lineament, drainage, soil, and rainfall …


Extraction And Characterization Of Fibres From The Bark Of Ficus Nekbudu Tree, Liberato V Haule Sep 2023

Extraction And Characterization Of Fibres From The Bark Of Ficus Nekbudu Tree, Liberato V Haule

Tanzania Journal of Engineering and Technology (TJET)

This paper investigates the extraction and characterization of fibres from the bark of the ficus nekbudu tree. The Ficus Nekbudu Fibres (FNF) was extracted from the bark by retting in water and then treatment with sodium hydroxide solution. The extracted FNF was analysed for chemical composition, physical, tensile, surface, structural and thermal stability properties. Findings on the chemical composition indicated that FNF has cellulose (49.9 %), lignin (13.4%), ash (7.1%) and water content (8.1%). From the physical investigation it was found that FNF has density (1.42 ± 0.005 g/cm3) and moisture regain (9.2 ±0.3%). From mechanical investigation it was found …


Designing A Cylindrical Capacitive Based Sensor For Monitoring The Table Salt’S Moisture Content During Iodization, Mwajuma Lungo Sep 2023

Designing A Cylindrical Capacitive Based Sensor For Monitoring The Table Salt’S Moisture Content During Iodization, Mwajuma Lungo

Tanzania Journal of Engineering and Technology (TJET)

Coaxial cylinder capacitive moisture sensor for determination of moisture content of table salts has been fabricated. The CMS method for determination of moisture content of table salts overcomes the effect of evaporation of iodine in table salt which results from heating in the oven drying method. The CMS overcomes the polarization effect result from the resistive methods of moisture content determination and it is non expensive to construct and it has high accuracy since measurements involves programming system in interpretation of the results. In this research, moisture content sensor based on capacitive principal created using two coaxial cylinders with height …


Comparison Of End-Point Energies Of Bremsstrahlung Photons From 28 Ghz Ecr Ion Source In Three Measurement Locations, Mwingereza John Kumwenda Dr Sep 2023

Comparison Of End-Point Energies Of Bremsstrahlung Photons From 28 Ghz Ecr Ion Source In Three Measurement Locations, Mwingereza John Kumwenda Dr

Tanzania Journal of Engineering and Technology (TJET)

Bremsstrahlung photons measurement show elevated energy emission beyond critical energy in 28-GHz ECR and its nature is not revealed. Thus, the aim of this study is to unveil the nature of high end-point energies at the three measurement locations. Bremsstrahlung photons from a 28-GHz ECR ion source were measured at Busan center of Korean Basic Science Institute (KBSI). The gamma-ray detection system consists of three round type NaI(Tl) scintillation detectors placed 62 cm radially from the beam axis at the three measurement locations namely injection, centre and extraction sides of an ECR ion source, and a NaI(Tl) scintillation detector placed …


Renewable Energy Potential Assessment For Improving Electric Power Availability In Urban Area: A Case Of Msigani Ward In Ubungo Municipal, Tanzania, Respicius Kiiza Sep 2023

Renewable Energy Potential Assessment For Improving Electric Power Availability In Urban Area: A Case Of Msigani Ward In Ubungo Municipal, Tanzania, Respicius Kiiza

Tanzania Journal of Engineering and Technology (TJET)

The demand for electricity in urban areas of the developing countries like Tanzania is increasing rapidly due to factors such as increasing population, expansion of economic activities and industrialization. Msigani ward is one of the fourteen (14) administrative urban wards in Ubungo Municipal, Dar es Salaam, located at latitude 6.8031 oS and longitude 39.1188 oE. Recently, there has been observed increase in power demand in this ward. This in turn has caused a supply deficit that sometimes led to large number of interruptions caused by frequent power outage and load shedding. The total capacity of the national grid is limited …


Assessing Spatio-Temporal Variations And Trends Of Rainfall Over Somalia From 1991 To 2020, Paul Ts Limbu Sr Sep 2023

Assessing Spatio-Temporal Variations And Trends Of Rainfall Over Somalia From 1991 To 2020, Paul Ts Limbu Sr

Tanzania Journal of Engineering and Technology (TJET)

This study aims to examine the spatiotemporal variability and trends of rainfall over Somalia using the Mann-Kendall (MK) test and Sen’s slope estimator to investigate the trend and magnitude of the rainfall changes and the arithmetic mean and coefficient of variation (CV) to examine the rainfall variability. To achieve this aim, the gridded monthly satellite rainfall datasets from Climate Hazards Group InfraRed Precipitation with Station (CHIRPS) for the period between 1991 and 2020 were used. Results show that annual rainfall generally exhibits bimodal rainfall distribution, March to May (Gu) and September to November (Deyr), though southern coastal regions receive extended …


Application Of Mangrove Timber In Reinforcing Concrete, John K. Makunza Jkm Sep 2023

Application Of Mangrove Timber In Reinforcing Concrete, John K. Makunza Jkm

Tanzania Journal of Engineering and Technology (TJET)

Use of mangrove timber beams for supporting floor slabs in historic buildings in Zanzibar Stone Town is still applied although the available structural data on mangrove timber is inadequate. This concern has called for an investigation on the structural properties of mangrove timber, so that the information obtained could help to establish the structural strength of the existing floor slabs in historic buildings. Hence, mangrove timber specimens were sampled from Zanzibar, and tested in the laboratory for their strengths in tension, compression and shear. The test results showed that mangrove is a hardwood timber of strength class D70, the highest …


A Multitask Learning Framework For Pilot Decontamination In 5g Massive Mimo, Crallet Victor Sep 2023

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 …


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 Sep 2023

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 …