Tanzania Journal of Engineering and Technology

Analysis of the Factors Affecting the Oil Recovery from Oilseeds in a Multistage Crosscurrent Leaching Process

2024-06-29T10:24:34+00:00

Assessment of the Factors Affecting the National ICT Broadband Backbone (NICTBB) Systems Restoration Time

2024-06-29T10:35:04+00:00

This study investigates the factors affecting the prolonged system restoration time when national ICT broadband backbone (NICTBB) services are affected by breakdown incidents. NICTBB is the government-owned backbone infrastructure constructed nationally by the Republic of Tanzania to increase the usage of ICT for equitable and sustainable socio-economic development and accelerate poverty reduction. This study utilised a mixture of exploratory and descriptive study approaches. The sample size determination was executed using purposing and simple random sampling, thus involving 289 respondents. The data reliability test was undertaken. It was followed by factor analysis, analysis of variances (ANOVA), linear regression analysis, and confirmed with confirmatory factor analysis (CFA) using IBM SPSS Amos 28 to test the model fitness. The study revealed that the maintenance centres are few and sparsely located, and the distance from maintenance centres increases travelling time, resulting in increased time to restore services. Some factors affecting the restoration time include initial infrastructure design not trenching to locate points of cut, absence of dedicated vehicles standby for NICTBB restoration, retirements of experienced and well-trained staff leaving behind untrained personnel for maintenance activities, and insufficient funds for maintenance. Lastly, power equipment is not looked upon as sometimes the services are down due to commercial power cuts, tripped circuit breakers, and batteries not being charged. Some recommendations include having proper maintenance processes, having enough restoration resources at all maintenance centres, and maintaining proper communication.

Data Communication Over Power-lines: A Review on Technical, and Applications Challenges

2024-02-12T13:16:30+00:00

This paper presents a review study on the data communication over power-lines, commonly referred to as power-line carrier, power-line communication (PLC), mains communications, or power-line digital subscriber line (PDSL). This study examines the technical and application advantages and challenges associated with adopting PLC as a preferred alternative technology for wideband or broadband data communication. The broader coverage area of the PLC network gives it a distinct advantage over other communication network technologies. Additionally, implementing a communication system using the existing power-line network is more cost-effective and less time-consuming compared to constructing a new network from scratch. However, the primary challenge lies in the fact that the power-line network is primarily designed for the distribution of electrical power within the frequency range of 50-60 Hz including the harmonics. This poses various obstacles such as electrical noise from appliances, signal distortions caused by the unregulated nature of the wiring, transformer bypassing, interference from high-frequency modulation, and variations in characteristic impedances, among others. Despite these challenges, the emergence of robust modulation techniques like Orthogonal Frequency Division Multiplexing (OFDM) and Direct-Sequence Spread Spectrum (DSSS), along with the development of Application-Specific Integrated Circuit (ASIC) density with improved processing speeds, as well as advancements in signal processing and error control coding techniques, have made the PLC network the most promising telecommunications access network.

An Investigation of Heavy Metal Composition and Associated Health Risks from Selected Groundwater Wells in Temeke, Dar-es-Salaam

2024-04-29T15:56:58+00:00

Water quality continues to be the challenge to residents in Dar es Salaam due to various anthropogenic activities in the city. This study was conducted to assess groundwater quality by determining concentrations of heavy metals. Both probability and Nonprobability sampling techniques were used to collect samples from 40 groundwater wells in 24 wards of Temeke municipal and analysed using Microwave Plasma Atomic Emission Spectrometer (Agilent 4210 MP-AES) at the Geochemistry Laboratory of the University of Dar es Salaam. Results indicated varying heavy metal concentrations ranging from 0.71 ± 0.08 to 6.64 ± 0.21 mg/l for As, 0.02 ± 0.01 to 0.07 ± 0.01 mg/l for Co and 0.16 ± 0.01 to 0.02 ± 0.01 mg/l for Pb. The As, Co and Pb concentrations exceeded (P < 0.05) the recommended TBS standards of 0.05 mg/l, 0.003 mg/l and 0.01 mg/l respectively. Other concentrations ranged from 0.01 ± 0.01 to 0.88 ± 0.01 mg/l for Cu, 0.02 ± 0.01 to 3.55 ± 0.02 mg/l for Fe, 0.00 ± 0.00 to 4.63 ± 0.03 mg/l for Mn and 0.01 ± 0.01 to 3.00 ± 0.01 mg/l for Zn. The Cu, Fe, Mn and Zn concentrations were below (P > 0.05) the allowable TBS limits of 0.05 mg/l, 0.3 mg/l, 0.1 mg/l and 3 mg/l respectively. Health risk analysis revealed potential adverse health effects from long term consumption of As, Mn and Pb with Hazard Quotient exceeding 1 (HQ > 1). The Hazard Index (HI) for all groundwater samples was also above 1 (HI > 1) indicating a higher likelihood of adverse health effects. The study concluded that groundwater wells in Temeke Municipal are affected through natural and anthropogenic activities leading to high levels of heavy metal concentrations. Also, this study provides valuable information on risk associated by continued usage of groundwater in Temeke region and hence informs respective stakeholders on groundwater quality and potential risks thereby emphasizing the need for remedial measures and stricter regulations to safeguard public health. The study recommends the need for regular groundwater quality and safety monitoring to assess the levels of heavy metals concentrations and implement sustainable groundwater management strategies to address the increasing water demand in Temeke municipal, Dar es Salaam.

Development and Testing of Small-Scale Flash Dryer for Maize Bran

2024-07-01T15:58:20+00:00

Sun drying is the most common technique used to dry various food products due to its economic convenience. However, it is not effective owing to its unreliable nature leading to microbial deterioration and aflatoxin contamination of food. In Tanzania, about 1.3 million tonnes of maize bran are at risk of deterioration annually due to improper drying. The aim of this study was to design, fabricate and test an efficient small-scale flash dryer for maize bran. Using principles of material and energy balance, a small-scale flash dryer with a throughput of 500 kg of dry product per hour was designed resulting in a nominal diameter of 387 mm and a drying length of 20 m. Design calculations and drawings were done using MS Excel 2021 and SolidWorks 2018 respectively. Empirical procedures were used to fabricate and test the dryer. The material of construction used in the flash duct was food grade (stainless steel, SS 201). A fuel blend of Waste Engine Oil (WEO) and diesel (85%-15%) was used with a novel heavy oil burner. It was observed that at an inlet air temperature of 150 °C and air velocity of 12 m/s, moist maize bran was dried from 37% to 10% w.b. The fabricated flash dryer's energy efficiency, specific energy consumption, and specific energy utilization are 74%, 3.4 MJ/kg water evaporated, and 1.71 MJ/kg dry maize bran respectively. It was concluded that the fabricated small-scale flash dryer displayed improved energy performance compared to others presented in literature. Better instrumentation was recommended for feedback control on burner operation and process monitoring which further enhances the performance of the fabricated small-scale flash dryer.

Assessment of Web Security Vulnerabilities for Common Open Source Virtualization Software

2024-08-12T09:18:18+00:00

Open-source hypervisors have emerged as an integral technology for virtualizing server resources in cloud and data center computing. Hypervisor security efficiency is determined by virtual machine isolation, which is a de facto adoption factor in the selection process, as well as its ability to respond to web attacks. This paper assesses the security performance of Proxmox VE and XenServer for type 1 hypervisors, and Kernel Virtual Machine and Oracle Virtual Box for type 2 hypervisors. Security analysis was conducted using common exposures extracted from vulnerability databases and mapped against the OWASP 2013 and 2017 projects. For clarity, experiments were carried out on a testbed with prebuilt virtual machines, each hosting one hypervisor installed as an attack target. Kali Linux was configured in one virtual machine to run recursive penetration testing for information gathering, vulnerability detection, penetration attempts, and exploitation of weak spots. The infrastructure was set in both homogeneous and heterogeneous execution environments, with a series of tests nested with each other. All four hypervisors are vulnerable to physical kernel isolation, as unprivileged users can gain root access and launch guest-to-guest and host-to-guest attacks. Among the two, guest-to-guest attacks were found to be more common than host-to-guest attacks, indicating that virtual machine isolation is weaker than the underlying host. Type 1 hypervisors have a lower rate of host-to-guest attacks than guest to-guest attacks, implying that XenServer and Proxmox VE provide better isolation than KVM and OVB due to the near-native speed, security, and efficiency of their virtual machines. All four hypervisors were found to be vulnerable to buffer overflow exploits and error-triggering sensitive information leaks, which were primarily caused by adopter default misconfigurations in the deployment process rather than software design flaws. This implies that greater efforts are required by open-source adopters when shifting from physical to virtual computing.

Necessity of Education for Efficient and Sustainable Production and Consumption of Energy in Tanzania

2024-08-29T08:18:43+00:00

This paper reports the findings of a study that was conducted in Tanzania to grasp how the policies, plans and curricula at different levels of education accommodate knowledge gathered on energy to support the fostering of energy education. The study interrogated what necessitates the inclusion of energy education into the curricula in Tanzania. Subscribing to a qualitative approach, the study employed a desk research method to review curricula and other documents guiding secondary and university level education in the country. The study found out that heightening people’s consumption of energy for domestic and industrial purposes constituted the main issue that necessitates the provision of energy education. Collected data further show that, the Tanzanian curricula targets giving the people knowledge and awareness for safety and how to optimise the use of energy sources, both effectively and efficiently. Moreover, energy education is essentially due to threats of depletion, discovery of new sources of energy, and the need for skilled workers. Such education is also necessary to address the need for expertise and technological advancements in production and consumption methods. The threat of environmental degradation and global warming also make it necessary that people become energy literate. In some cases, energy education aims to meet the investors’ needs and provide general knowledge in addition to serving diplomatic purposes. Overall, the study found out that energy education is essential for ensuring the country has sustained energy supply and use, while meeting the needs of the population, and fostering economic growth.

‘‘Domicilelessness’’ and Livelihoods in Urban Areas: Case of Maasai in Dar es Salaam, Tanzania

2024-09-02T10:13:49+00:00

The study aimed at demonstrating Maasai migration into Dar es Salaam urban areas and their challenges in accessing accommodation. Methodologically, the study deployed secondary data analysis following a descriptive research design. Furthermore, this study was conducted through both qualitative and quantitative research approaches. The study was conducted from 2018 to 2022 of which a random sample of 100 (N=100) was targeted. The data was analyzed using the Statistical Package for Social Sciences (SPSS Version 16). Findings: The Maasai means of accommodation are divided into four main categories: completed houses (6%), under-construction sites (39%), halfway constructed and abandoned structures (31%), and car garages and under trees (24%). These groups lack basic services such as water, toilets, and cooking spaces, and are often confounded and inhabitable, exposing them to risk of contracting various diseases. Maasai engage in livelihood activities both day and night, with hairdressing, handcraft, and petty trading being their primary activities. At night, they work as watchmen and those not engaged in anything spend time sleeping. Inclusive policies catering for minority groups in urban areas need to be put in place in Dar es Salaam.

Perona-Malik Diffusion-Driven Regularization for Image Resolution Enhancement in Electrical Capacitance Tomography

2024-05-24T07:27:28+00:00

Electrical Capacitance Tomography (ECT) is a non-invasive promising method for monitoring industrial processes, such as oil-gas flow in pipelines and solid-gas flow in pneumatic systems. Despite its potential benefits, ECT generates poor-quality images, often used only for qualitative analysis. A non-linear relationship between measured capacitances and permittivity distribution and the ill-posedness of the sensitivity matrix elements causes this limitation. This hinders the applicability of ECT in monitoring online industrial process applications. This work proposes a reconstruction method based on a nonlinear diffusion function to generate high-quality images from the measured capacitance data from the ECT system. The diffusion regularization functional helps to remove noise and preserve semantic features. Experimental results reveal that the proposed method generates high-quality and visually appealing images with a 15% reduction in distribution error and a 10% increase in correlation coefficient compared to state-of-the-art methods such as linear back projection and projected landweber. This allows further investigation into how nonlinear anisotropic diffusion can improve the applicability of ECT systems in industrial control and monitoring.

An Evaluation of Business-Driven Reference Architecture for Big Data Analytics Implementation by Public Sector Organizations in Resource-Constrained Setting: A Case Study of Uganda

2024-05-03T04:59:18+00:00

Big Data Analytics (BDA) is a new area at the nexus of agenda, public sector organizations, and government business. It may satisfy the growing need for trustworthy, cost-effective services in the public sector for better, more informed decision-making processes. BDA has been proposed on the planning schedules of several public sector organizations and the government. Therefore, from the previous work, using Uganda as a case study, specifically the Uganda Bureau of Statistics (UBOS), Ministry of Health (MoH), and Ministry of Education and Sports (MoES), this study aims to evaluate a designed Business-Driven Reference Architecture for Big Data Analytics Implementation (BRABDAI) in public sector organizations. Using a quantitative research method, the BRABDAI was analytically assessed using a structured walkthrough technique by 18 IT experts in the fields of data analysis, IT/IS management, and solution architecting. The assessment criterion was composed of three components: functionality, usability/applicability, and traceability. The Statistical Package for the Social Sciences (SPSS) software was used for data analysis. The findings showed that the BRABDAI was useful for resolving the key issues preventing the successful implementation of the BDA in public sector organization settings and that it was also understandable and traceable. To improve the usage and acceptability of BDA implementation in public sector organizations, the study advises more research on this topic.

Assessing the Importance of Air-Decking Blasting in Controlling BIGV at an Open Pit Gold Mine in Tanzania using ANN Model

2024-06-14T05:45:16+00:00

Air-decking blasting technique is used to control blast induced ground vibration (BIGV) in several mines including open-pit gold mines located in Tanzania. While the importance of air-deck to control BIGV is practically evident, theoretical models such as BIGV prediction models cannot be used to assess the importance of air-decking. The main objective of this study was to assess the importance of the air-decking blasting technique to control BIGV using the artificial neural network (ANN) Model. To achieve this objective, ANNs were modeled and trained to learn the pattern of data using Multilayer Perception with Back Propagation to predict BIGV. The main results showed that the normalized importance of air-decking in predicting BIGV was 92.4%. Other important parameters were distance from blasting with a normalized importance of 100% and MIC which was relatively low with a normalized importance of about 46.2%. Parameters such as charge length, powder factor, bench height, charge per length, and stemming length were by far less important than air-decking. The ANN model developed in this study appeared to perform well by incorporating air decking parameters, which traditional BIGV predictors could not. The model also can predict BIGV with an error of about 1.8%. It was recommended that the air-decking technique used at the gold mine should be maintained and practiced to control BIGV for the sustainable development of the mining industry in Tanzania.

Modeling the Influence of Internal Factors on Vehicular Mobility Performance

2024-08-02T09:27:07+00:00

Traffic mobility is significantly influenced by road conditions and the internal factors governing vehicular performance. Internal factors play a crucial role in vehicular mobility, influencing vehicles operate and performance. While existing vehicular mobility models primarily address external factors, external factors such as governor, engine, gear train and differential unit remain underexplored. This study formulates a comprehensive model to address this gap, focusing on the internal components that affect vehicular mobility. The proposed model employs both analytical and numerical methods to derive transfer functions for these subsystems using Matrix Laboratory (MATLAB), aiming to capture the dynamic behavior of vehicles under various conditions. The model was evaluated by examining vehicle transaction times across different road surface qualities, measured by the International Roughness Index (IRI) values of 3.5, 3.0, and 2.0, and tractive forces ranging from 4500 N to 17750 N, with applied pedal forces of 50 N, 100 N, 150 N and 200 N. Results indicated that higher tractive forces lead to reduced transaction times, with IRI values of 3.5 m/km showing a decrease from 122.0 seconds to 31.0 seconds as tractive forces increased from 4500 N to 17750 N. Similarly, for IRI values of 2.0 m/km, the transaction times reduced from 67.5 seconds to 7.5 seconds under the same conditions. The analysis further demonstrated that increased applied pedal forces correspond to higher tractive forces, thereby enhancing vehicular mobility and performance. These findings highlight the critical role of internal factors in optimizing vehicular mobility and performance, suggesting that internal subsystem dynamics should be integrated into future mobility models for more accurate and comprehensive assessments.

The Effects of Corporate Culture on Firm Growth: Evidence from Tanzania’s Construction Firms

2023-03-15T08:36:58+00:00

Corporate culture is one of those important aspects that determine the growth of firms. This study investigates the effects of the different types of corporate culture on the growth of Tanzania’s local construction firms. A survey of 227 Tanzania’s construction firms was undertaken using semi-structured questionnaire. The data collected were quantitatively analysed using Stata 13.0 software. The study results indicate that only the hierarchy type of corporate culture positively and significantly impacts the growth of Tanzania’s construction firms. The other types of corporate culture, such as adhocracy, market, and clan had insignificant effects on the growth of the construction firms in Tanzania. The findings show that using the aggregated corporate culture construct is inappropriate in certain research contexts. Hence, the findings are useful in informing managers of Tanzania’s construction firms about the significant effects of hierarchy culture on the growth of firms. This enables them to create a working environment focusing on structured and formatted procedures.

Exploring the Transformation of Sustainable Collective Spaces

2024-08-14T13:51:03+00:00

A major challenge in collective space transformation is addressing the complexity of informal urbanisation in developing countries. Using a case study approach, this paper examines the concerns related to a particular informal settlement's sustainable collective space transformation. One of the key findings is that the absence of formal rules and regulations in the development of informal settlements in combination with land-grabbing leads to the absence of open spaces that could be used collectively. It is observed that sustainability in urban development is another body of critical thought that integrates several streams of current urban elements and embodies various conceptions of social-cultural, social-economic, environmental, and technological aspects as success factors for sustainable collective space transformation. As part of informal urbanisation, collective spaces should be addressed to lessen the intensity of restricted community spaces and create sustainable urban settings. Sustainable collective space development seems important in cities since it enhances several activities in the urban context with stable and appropriate collective spaces for community life. The paper concludes with a call for development actors, political commitment, and recognition of contextual responses when transforming collective spaces, rules set within informal settlements, and strategies branded for sustainable transformation.

Investigations of Cell Tower Antennas Parameters on Reduction of Radio Frequency Radiation Levels from Radio Base Stations

2024-08-01T06:39:02+00:00

populated areas has raised public health concerns due to increased exposure to radio frequency (RF) radiation emissions. Exposure to high levels of RF radiation can have potential thermal and non-thermal biological effects. Optimizing the configuration of cell tower antenna parameters is crucial for mitigating these radiation levels. This study therefore aims at systematically investigating the influence of different cell tower antenna parameters on reducing the RF radiation levels from mobile base stations. Field measurements were conducted at two cell sites shared by multiple mobile operators. Electric field strengths were measured at multiple locations around the cell sites. The impacts of various antenna parameters were analyzed, including the deployment of GSM spectrum within LTE services, number of carrier frequencies, antenna down-tilt, and transmission power. The analysis revealed that deploying the GSM spectrum within LTE services can reduce the overall radiation levels. Additionally, decreasing the number of carrier frequencies, increasing antenna down-tilt, and lowering transmission power were found to contribute to significant reductions in measured radiation levels. However, optimizing these antenna parameters to mitigate radiation can also degrade key mobile network performance indicators, such as coverage and capacity. These findings provide valuable insights into effective strategies for balancing the need to minimize RF radiation exposure from mobile base stations while maintaining acceptable mobile network service quality. Careful optimization of cell tower antenna configurations is essential to address public health concerns without compromising network performance.

Lean Manufacturing Practices in Tanzania: Exploring Awareness, Training and Capital Investment

2024-09-03T09:34:46+00:00

With the growing competition among industries in the world, manufacturing industries are now forced to adopt the Lean Manufacturing philosophy to improve their competitive abilities. The adoption of the philosophy is very low in developing countries such as Tanzania, as is demonstrated with 1% of publications and the lack of knowledge and capital for Lean Manufacturing implementation causes this. Furthermore, the contribution of the sector to the Gross Domestic Product in Tanzania is low and stands at 8.4%. The study wants to bridge the gap in training, capital and awareness of Lean Manufacturing in Tanzania. Survey and purposive sampling techniques were adopted in the study. A structured questionnaire was used to collect responses from 243 manufacturing industries of all sizes. Descriptive and inferential statistics were analysed with SPSS version 27.0.1. The results demonstrated that there is inadequate training for micro and small industries as more than 80% have not received any training, have inadequate funds whereby more than 95% have not allocated funds and low awareness with a mean score of below 3 out of 5. The status is contrary in medium and large industries, with more than 75% training provision. It was also revealed that 90% of large industries have allocated funds while for medium ones it is more than 39% and the awareness for Lean Manufacturing is high as they have a mean score of above 3. The Lean practices with high levels of awareness to all manufacturing industries are 5s, concurrent engineering and visual management. The low level of awareness, training and insufficient capital for Lean Manufacturing affect the adoptions of the philosophy in Tanzania. Therefore, the study will assist practitioners and policymakers in setting strategies for bridging the gap in the adoption of Lean Manufacturing in developing countries such as Tanzania.