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Tanzania Journal of Engineering and Technology (TJET)

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Full-Text Articles in Process Control and Systems

Review On Modifications Of Sisal Fibers For Textile Applications, Liberato V Haule Jun 2023

Review On Modifications Of Sisal Fibers For Textile Applications, Liberato V Haule

Tanzania Journal of Engineering and Technology (TJET)

Properties of sisal fibers such as high coarseness and poor drapability made the fibers less suitable in production of conventional textiles compared to synthetic fibers. The environmental consciousness and depletion of petrochemical resources have attracted researchers on investigating the use of natural fibers in the industrial production of conventional textiles. Sisal is among highly researched natural fibers due to its features such as strength, recyclability, availability, low processing cost, light weight and ease process ability. This paper reviews possible modifications of sisal fibers to enhance performance in conventional textiles applications


Towards Lean Manufacturing In Developing Countries: Research Gaps And Directions In Tanzania, Francis D. Sinkamba Feb 2023

Towards Lean Manufacturing In Developing Countries: Research Gaps And Directions In Tanzania, Francis D. Sinkamba

Tanzania Journal of Engineering and Technology (TJET)

In the current knowledge-driven economy, many industries across the globe are forced to adopt manufacturing technologies such as lean manufacturing to remain competitive in the globalized world. Despite the increase in lean manufacturing implementations, the adoption rate in Tanzania is very low and estimated to be 8 percent. Likewise, the sustainability of lean manufacturing tools and practices is still questionable, which shows the need to develop lean maturity models. To date, several lean maturity models have been developed but there is ARTICLE INFO Submitted: July 5, 2022 Revised: Sept. 28, 2022 Presented: Oct. 20, 2022 a lack of maturity models …


Current And Future Trends Of Construction Project Performance Models: A Review, Method Mtana Feb 2023

Current And Future Trends Of Construction Project Performance Models: A Review, Method Mtana

Tanzania Journal of Engineering and Technology (TJET)

The construction industry (CI) has experienced outstanding growth and contributed to economic growth for many countries, with enormous foreign investments that require quality projects. High pressure to reduce the construction cost and time commonly put the industry at risk of lower quality and safety of the construction facilities. Like many other developing countries, Tanzania needs more stringent quality control measures in the construction sector to contribute positively to sustainable growth. This study thus reviews current and future trends in construction industry performance in Tanzania. The literature review on construction projects (CPs) performance is based on information on time overruns from …


Factors Influencing Total Productive Maintenance Implementation For Thermal Generation Plants, Ismail W. R. Taifa Dr Feb 2023

Factors Influencing Total Productive Maintenance Implementation For Thermal Generation Plants, Ismail W. R. Taifa Dr

Tanzania Journal of Engineering and Technology (TJET)

This study accepts that the technical and administrative factors can amplify effective total productive maintenance (TPM) implementation at thermal generation plants. It is noted that there is a limited number of studies that have attempted to understand the subject of TPM implementation in the energy sector. Noting this shortcoming, the authors thought it crucial to generate empirical evidence on the factors influencing effective TPM implementation for thermal generation plants, with evidence from gas-fired plants. A sample of 88 respondents was selected and consulted. Data were collected through questionnaires and analyzed quantitatively by inferential statistics and qualitatively through thematic analysis using …


Towards The Development Of A Framework For Assessing Organizational Governance Maturity For Technical Audit Of Public Works, George Haule Feb 2023

Towards The Development Of A Framework For Assessing Organizational Governance Maturity For Technical Audit Of Public Works, George Haule

Tanzania Journal of Engineering and Technology (TJET)

The quality of the audit work and its products is often associated with the organizational maturity of the audit function. The absence of a well-defined organizational maturity for an audit function leads to poor quality of audit work or products and ineffective audit function. The lack of a framework for measuring governance maturity was identified as a major deterrent factor to the attainment of quality audit work. Measuring the governance maturity of the technical audit of public works is challenging due to the absence of a maturity framework that fits its needs. The noted shortcomings include: (a) existing maturity frameworks …


Exploring Current And Future Research Trends On Safety Climate In Construction Projects, Kamugisha Joseph Kajumulo Feb 2023

Exploring Current And Future Research Trends On Safety Climate In Construction Projects, Kamugisha Joseph Kajumulo

Tanzania Journal of Engineering and Technology (TJET)

Clients, consultants, and contractors in the construction industry can benefit from a safety climate by obtaining knowledge of attitudes and perceptions for better safety outcomes. However, the current and future research trends for safety climate in construction projects have not yet been fully examined. In order to solve this problem, a systematic review of previous research findings using a social network approach must be conducted, and future trends for the safety climate in building projects must be identified. Sixty-three peer reviewed articles were gathered to study the literature on safety climate in construction projects. A social network approach was employed …


The Fourth Industrial Revolution: Opportunities And Challenges To The Future Of Mechanical Engineering, Ulingeta O.L. Mbamba Feb 2023

The Fourth Industrial Revolution: Opportunities And Challenges To The Future Of Mechanical Engineering, Ulingeta O.L. Mbamba

Tanzania Journal of Engineering and Technology (TJET)

This paper provides a conceptual overview of the developments of the Fourth Industrial Revolution (4IR) and derives challenges and opportunities for the future of the mechanical engineering profession. The paper broadly defines 4IR as the fusion of technologies and interaction across physical, digital and biological aspects, while defining mechanical engineering as "a multi-faceted discipline that encompasses the teaching, practice and guidance of others in the development and application of scientific principles to mechanical systems". The paper looks specifically at developments in the Internet of Things (IoT), blockchain technology, robotics, Big Data analytics, biotechnology, nanotechnology, 3D printing and artificial intelligence and …


Designing And Manufacturing Of Vegetable Slicing Machine, Juma Nuhu Msuya Feb 2023

Designing And Manufacturing Of Vegetable Slicing Machine, Juma Nuhu Msuya

Tanzania Journal of Engineering and Technology (TJET)

Agro-processing industry is faced with a challenge of slicing of vegetables for immediate consumption. This stems from the fact that the traditional slicing methods use bare hands, and knives. This method is faced with shortcomings of inefficiency, poor hygiene, and significant dangers to injury. If vegetables are not sliced, their drying takes longer, may possibly be spoiled, and cannot be stored for future uses. Therefore, this paper strives to design a vegetable slicing machine to increase the efficiency of the drying process as a post-processing step. The study employed a Pugh’s design model to design the machine and manufacture it. …


Performance Evaluation Of Udsm Network To Deliver Multimedia Elearning Contents: Case Of Coict, Mercy Mbise Dec 2022

Performance Evaluation Of Udsm Network To Deliver Multimedia Elearning Contents: Case Of Coict, Mercy Mbise

Tanzania Journal of Engineering and Technology (TJET)

The use of technology in education in Sub-Saharan Africa has been reported to be hindered by many factors including inadequate Information and Communication Technology (ICT) infrastructure, low internet speed, and lack of skills to use educational technologies. This paper aim at evaluating how the available ICT infrastructure at the College of Information and Communication Technologies (CoICT) can support, with acceptable Quality of Service (QoS), the delivery of multimedia applications for eLearning services. The evaluation was performed over a network testbed implemented in a computer laboratory for wired and wireless connections. The testbed consisted of five personal computers (PCs) connected via …


Investigating The Support For Agility In Developing Government Software Systems: A Case Of Three East African Countries, Leonard Peter Binamungu Dec 2022

Investigating The Support For Agility In Developing Government Software Systems: A Case Of Three East African Countries, Leonard Peter Binamungu

Tanzania Journal of Engineering and Technology (TJET)

Agile Software Development Methods support an iterative and incremental way of developing software systems while responding to change by prioritising various aspects at different times. This differs from traditional sequential methods like Waterfall, in which one software development stage has to be completed before starting the next stage. To produce software systems that meet the requirements of their institutions, several governments in Africa have issued standards and guidelines to be followed during the development of government software systems. Such standards and guidelines specify the specific activities and deliverables for each stage of software development. While well-intentioned, such guidelines and standards …


Fermentability Of Concentrated Sulfuric Acid Hydrolyzates From Aspenwood And Pinewood, Kando Janga Dec 2020

Fermentability Of Concentrated Sulfuric Acid Hydrolyzates From Aspenwood And Pinewood, Kando Janga

Tanzania Journal of Engineering and Technology (TJET)

The fermentability of hydrolyzates derived from two-stage concentrated sulfuric acid hydrolysis of Trembling aspen (Populus tremula) and Scots pine (Pinus sylvestris) were investigated. Three types of hydrolyzates were produced at mild, moderate and high decrystallization severity conditions. Portions of each of the original hydrolyzates were concentrated by vacuum evaporation to increase the sugar fraction to simulate industrial applications. Both sets of hydrolyzates were fermented anaerobically using Saccharomyces cerevisiae ATCC 96581. After 23 hours of fermentation, complete glucose consumption was observed for all the original hydrolyzates, with no signs of inhibition. The ethanol yields from these hydrolyzates ranged from 68% to …


The Potentials Of Faecal Sludge Treatment Using Local Conditioners In Tanzania: A Review, Doglas Benjamin1 Dec 2019

The Potentials Of Faecal Sludge Treatment Using Local Conditioners In Tanzania: A Review, Doglas Benjamin1

Tanzania Journal of Engineering and Technology (TJET)

Worldwide, every day human beings generate millions of tons of Faecal Sludge (FS), which is rich in water, nutrients, energy, and organic compounds. Yet FS is not being managed in a way that permits us to derive value from its reuse, while at the same time, millions of farmers struggle with depleted soils and lack of water. In most of the developing countries, energy for cooking is mainly derived from cutting of trees, either as wood or charcoal. Resource recovery and reuse from FS can create livelihoods, enhance food security, support green economies, reduce waste and contribute to cost recovery …


Calibration Of Hdm-4 For Use In Pavement Management Systems (Pms), Nurdin Mushule Dec 2009

Calibration Of Hdm-4 For Use In Pavement Management Systems (Pms), Nurdin Mushule

Tanzania Journal of Engineering and Technology (TJET)

One of major problems of road management in developing countries is the lack of decision making tools for preparing road maintenance programmes. This results in poor resource allocation and poor utilisation of existing assets. Pavement management systems (PMS) have been developed around the world in order to assist with the pavement management process in a co-ordinated and systematic manner. Some developed countries have derived pavement performance models that are suited to local conditions by setting up long term pavement performance studies. Conversely, most developing countries do not have the resources required to set up similar large-scale field experiments. However, validation …


A Systemic Framework For Implementation Of Tqm Programmes, Emanuel Mjema Dec 2009

A Systemic Framework For Implementation Of Tqm Programmes, Emanuel Mjema

Tanzania Journal of Engineering and Technology (TJET)

The purpose of this paper is to present a systemic framework for implementation of TQM program in a manufacturing organisation that produces motor vehicle components in Port Elizabeth - South Africa. The approach used included conceptualisation of the systemic framework and then involvement of the stakeholders in adding scenarios to be considered in the design and implementing the framework in the real field. The findings obtained during the implementation of the systemic framework established that reduction of scrap rate, reduction of production costs, reduction of cycle time and employee motivation could be achieved through the implementation of a Systemic Framework …


The Multivariate Statistical Analysis Of Abiotic Parameters Of The Lake Tanganyika Sub Catchment, Hudson Nkotagu Dec 2008

The Multivariate Statistical Analysis Of Abiotic Parameters Of The Lake Tanganyika Sub Catchment, Hudson Nkotagu

Tanzania Journal of Engineering and Technology (TJET)

Results from multivariate statistical analysis of abiotic parameters conducted during the dry season at 20 accessible sites on 8 rivers, 2 lakes and a dam covering the Lake Tanganyika sub catchment are discussed. Standard methods were used to determine the levels of abiotic parameters from water samples. Physical parameters including DO, EC, Eh, turbidity, temperature, pH and secchi transparency were measured in situ while chlorophyll a was determined in the laboratory. Nutrients such as NO3-, SiO2, PO4 3- and Fe2+ were determined along with HCO3-. Factor analysis resulted in four factors including increased primary productivity, redox conditions, dissolution, and reduction …


Socio-Economic Impacts Of Computer Viruses In Tanzania, M Victor Jun 2006

Socio-Economic Impacts Of Computer Viruses In Tanzania, M Victor

Tanzania Journal of Engineering and Technology (TJET)

This paper reports on a research project conducted with an objective of identifying and assessing various approaches used by different computer users (Management, System Administrators and end users) in Tanzania to combat computer viruses (CVs), and to assess users' awareness level on CVs. Specifically, the study aimed at assessing the awareness level on CVs to the Tanzanian business community; analyze the socio -economic impact caused by CVs in Tanzania and; assess existing methods, capacity and limitations on controlling CVs in Tanzania. Data was collected using both questionnaires and interview from financial institutions such as NBC and BOT, and telecommunications sector …


Degradation Of Waterfront Reinforced Concrete Structures At The Port Of Dar Es Salaam, I Sanga Jun 2005

Degradation Of Waterfront Reinforced Concrete Structures At The Port Of Dar Es Salaam, I Sanga

Tanzania Journal of Engineering and Technology (TJET)

The paper summarises the results of an investigation done on piers at the Dar es Salaam Port. The problem facing these structures and marine facilities is their exposure to aggressive environmental phenomena. The paper presents an investigation of the strength and corrosion of concrete seaport piers so as to determine degradation of the reinforced concrete waterfront structures in the port of Dar es Salaam. For instance the structures at a dhow quay terminal had been in use for about 100 years. The facility was in bad condition as the concrete had been badly damaged due to corrosion. Some of the …


Participatory Evaluation And Improvement Of Cassava Processing Machines For The Eastern Zone Of Tanzania, V Silayo Dec 2004

Participatory Evaluation And Improvement Of Cassava Processing Machines For The Eastern Zone Of Tanzania, V Silayo

Tanzania Journal of Engineering and Technology (TJET)

Cassava processing machines previously introduced in Tanzania were chippers and graters of the International Institute Of Tropical Agriculture (IITA) design. Popularization of such machmes in Tanzania required thorough participatory testing with stakeholders. When tested with farmers in Muheza and Kibaha districts average throughputs were 11-18 kg/h, 752 kg/h and 270 kg/hfor the manual chipper, engine-powered chipper and the engine-powered grater, respectively. Despite their low throughputs the manual chipper and the grater were Veo difficult to operate, and therefore demanded improvement. Improvement on these machines included modifications on the design for increased throughput, ease of operation and safety. The improved machines …


Review Of The Product Development Process And Information Flow In The Manufacturing Industry: Problems And A Possible Wav Forward, E Opiyo Jun 2004

Review Of The Product Development Process And Information Flow In The Manufacturing Industry: Problems And A Possible Wav Forward, E Opiyo

Tanzania Journal of Engineering and Technology (TJET)

No abstract provided.


Centrifugal Extraction Of Avocado Oil From The Pulp, J. W. Ntalikwa Dec 2003

Centrifugal Extraction Of Avocado Oil From The Pulp, J. W. Ntalikwa

Tanzania Journal of Engineering and Technology (TJET)

Absract


Simulation Of The Communication Process In A Pin Mill, Ambrose J. M. Itika Dec 2003

Simulation Of The Communication Process In A Pin Mill, Ambrose J. M. Itika

Tanzania Journal of Engineering and Technology (TJET)

Prediction of the performance of comminution equipment by mathematical models and simulation poses a great challenge to the chemical engineer. This paper describes the simulation of grinding results obtained using an impact mill. Single particle results have been used to generate breakage and selection coefficients that were used for the evaluation of the model. Results have shown that simulation model is in good agreement with the experimental data obtained at a circumferential speed above 60 m/s. At lower speeds, the models shows only partial agreement in the middle particle size ranges. The application of the model is therefore limited for …


Discrete Element Modelling Of The Abrasive Dehulling Process Of Sorghum And Millet, E. L. Lazaro Dec 2002

Discrete Element Modelling Of The Abrasive Dehulling Process Of Sorghum And Millet, E. L. Lazaro

Tanzania Journal of Engineering and Technology (TJET)

The abrasive dehulling process of sorghum and millet was modelled using a three-dimensional discrete element model. The model was validated by comparison between experimental and simulation results. Good correlation between experimental and simulation results was obtained. Several numerical experiments were also carried out using the developed model to investigate the influence of mill and grain parameters on dehulling of sorghum and millet. The simulated results correlated well with experimental results from literature. The developed model therefore provides a simple and cheap tool, which can be used to study the dehulling process in more detail than, is currently possible using the …


Comparative Analysis Of Rng K-E And 'Standard' K-C Models For Fluid Flow Around A Cylinder, A Temu Jun 2001

Comparative Analysis Of Rng K-E And 'Standard' K-C Models For Fluid Flow Around A Cylinder, A Temu

Tanzania Journal of Engineering and Technology (TJET)

A two-dimensional computational scheme for simulating fluid flow around a cylinder was investigated. RNG (Re-NOrmalisation Group) and 'standard' turbulent closure models were used. simulation was implemented with assistance OfFLOW-3D computational fluid dynamics (CFD) code. The governing equation Of fluid motion, in Eulerian form, included body forces as well as surface forces. The computational model predictions for fluid velocity showed good agreement between the two models. Comparison Of the viscosities showed a large deviation from the two models, with RNG k-E model giving a better approximation. Comparison Of the velocity around the cylinder, as obtained from RNG k-c model, with approximation …


The Effect Of System And Oxygen Partial Pressure On Single Coal Particle Heterogeneous Ignition Temperature Under Conditions Of Negligible Convection; Experimental Observation, H. Katalambula Dec 1999

The Effect Of System And Oxygen Partial Pressure On Single Coal Particle Heterogeneous Ignition Temperature Under Conditions Of Negligible Convection; Experimental Observation, H. Katalambula

Tanzania Journal of Engineering and Technology (TJET)

Abstract Under conditions of high volatile concentrations, the influence of oxygen concentration on single coal particle ignition becomes more significant. The high volatile concentration conditions have been simulated by employing a microgravity environment. Results show that under these conditions, the heterogeneous ignition temperature decreases faster with increasing oxygen concentration than under normal conditions. The ignition temperature also decreases with increasing system and oxygen partial pressure under both conditions. Generally, the system and oxygen partial pressure show similar and complimenting effects on ignition temperature.


Application Of Vibrational Techniques In Determination Of Dynamic Properties Of Agricultural Products-State Of The Arton Of Vibrational Techniques In Determination Of Dynamic Properties Of Agricultural Products-State Of The Art, Silas Kajuna Dec 1999

Application Of Vibrational Techniques In Determination Of Dynamic Properties Of Agricultural Products-State Of The Arton Of Vibrational Techniques In Determination Of Dynamic Properties Of Agricultural Products-State Of The Art, Silas Kajuna

Tanzania Journal of Engineering and Technology (TJET)

Vibration is one of the techniques employed in the determination of dynamic properties of fruits and vegetables. It entails generation of a mechanical or acoustic vibrational signal which is propagated through the flesh of the agricultural material. A transducer is either attached or held close to the specimen to monitor the propagation of the signal through the specimen. The manner in which the signal is transmitted through the material is analyzed, and the dynamic properties of the specimen which relate to its firmness or its internal being are derived. The technique has been around for the past 30 years or …


Measurement Of Markstein Lengths In Laminar Spherical Explosion Flames, E .M.J Mushi Dec 1999

Measurement Of Markstein Lengths In Laminar Spherical Explosion Flames, E .M.J Mushi

Tanzania Journal of Engineering and Technology (TJET)

Schlieren photography was used to record the development of spherical flames in a combustion bomb. Flame speed and flame stretch were evaluated from the data and used to evaluate Markstein lengths and numbers. The results indicate a strong influence of both the spark discharge energy and equivalence ratio. Low spark discharge energy is observed to give rise to more unstable flames compared to high energy sparks. It is observed that for the range of energy tested, 80 and 400 mJ gave the best stability for the flames. For equivalence ratio less or equal to 1.225 an 80 mJ discharge results …


Use Of Dissolved Oxygen Concentration Probes In Biological Wastewater Treatment Plants, S Manyele Jun 1998

Use Of Dissolved Oxygen Concentration Probes In Biological Wastewater Treatment Plants, S Manyele

Tanzania Journal of Engineering and Technology (TJET)

A study on use Of dissolved oxygen probes (DOP) for measurement Of oxygen concentration in warer and wastewater treatment is presented. The principles Of operation, design considerations and selection criteria for Two types of probes, viz. galvanic and polarographic, are discussed Use of polarographic probes in n rhree-phase fluidized bed bioreactor and in laboratory experiments is presented and discussed. The effect of airflow rate and treatment time on dissolved oxygen concentration was found to be significant. It was found that polarographic probes are important equipment in determining the pollution of the industrial effluents. Finally, the use of the DOC probes …


An Alternative Method Of Interfacing A Dc Motor To A Microprocessor For Mo- Tion Control, M Selekwa Jun 1994

An Alternative Method Of Interfacing A Dc Motor To A Microprocessor For Mo- Tion Control, M Selekwa

Tanzania Journal of Engineering and Technology (TJET)

A Simple and cheap alternative method Of interfacing a permanent mag- net dc motor to a motion control using switch- ing transistor motor drivers is presented. This method involves the use Of very few transistor-transistor logic (TTL) devices and a 555 timer to pro- duce a pulse width modulated (P WM) signal which is required by the mo- ror driver. The motor driver in this case should be of an H-bridge type. Like other methods currently in use, it relieves the MPU of all timing func- tions which are necessary in the generation of P WM signals. The present method, …


Investigation On The Use Of Ethyl Acetate As Solvent For Seed Oil Extraction, E. L. Rivera Porras Jun 1990

Investigation On The Use Of Ethyl Acetate As Solvent For Seed Oil Extraction, E. L. Rivera Porras

Tanzania Journal of Engineering and Technology (TJET)

An investigation on the use of ethyl acetate as a solvent for the seedoil industry was carried out. As hexane is the most used solvent in extraction of oil from seeds, the study focuses on the comparison of the two solvents. The parameters studied were: contact time between solvent and seed cake, temperature of the solvent, quantity of solvent used for extraction and type of solvent. The results are presented on a relative basis where hexane is given a factor of 100. From the results obtained it can be seen that ethyl acetate is in general a better solvent than …