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Full-Text Articles in Risk Analysis

Identification Of Unbalanced Forces And Foundation Parameters Of Rotating Machines From Vibration Measurements, Nalitolela G Dec 2008

Identification Of Unbalanced Forces And Foundation Parameters Of Rotating Machines From Vibration Measurements, Nalitolela G

Tanzania Journal of Engineering and Technology (TJET)

A technique is described to use measured vibration data of a rotating machine and its foundation to identify unbalanced forces, stiffness and damping parameters of the mountings, and the parameters of the foundation. It is based on an idealisation treating the rotor, the machine structure and the foundation as rigid masses supported by springs and dampers. Operational vibration data of the machine and its foundation before and after the rotating unbalanced forces are perturbed by adding unbalanced mass to the rotor are used in the identification procedure. Once the parameters are identified, dynamic forces transmitted to the foundation can be …


Application Of Non-Destructive Testing In Evaluating Reinforced Concrete Structural Elements In Buildings, I Rubaratuka Jun 2008

Application Of Non-Destructive Testing In Evaluating Reinforced Concrete Structural Elements In Buildings, I Rubaratuka

Tanzania Journal of Engineering and Technology (TJET)

Of recent a large number of existing reinforced concrete buildings have required reconstruction, renovation and improvement. This tendency poses a number of problems that have to be solved, the main one being to determine the actual strength condition of the structural components/elements of the building. It includes determination of the quality of materials used, specification of the types and description of apparent faults and damages and extent of wear of the building. To undertake this evaluation, non – destructive testing methods are used. In this paper, applications of non – destructive testing methods to determine the strength state of reinforced …


Quality Control In The Construction Of Reinforced Concrete Buildings In Dar Es Salaam, I Rubaratuka Jun 2008

Quality Control In The Construction Of Reinforced Concrete Buildings In Dar Es Salaam, I Rubaratuka

Tanzania Journal of Engineering and Technology (TJET)

Quality Control in the construction industry is very important to ensure that what is being done conforms to the applicable standards or good practice and the contract documents. In this article, results of investigations conducted at different construction sites for reinforced concrete buildings in Dar es Salaam to check if quality control measures are being implemented are discussed. It has been established that generally quality control is not properly carried out. Finally, measures to enhance quality control on sites are outlined.


Strategies For Promoting The Use Of Concrete Pavements In Tanzania: Technical And Institutional Considerations, Mfinanga A Jun 2008

Strategies For Promoting The Use Of Concrete Pavements In Tanzania: Technical And Institutional Considerations, Mfinanga A

Tanzania Journal of Engineering and Technology (TJET)

High-type roads in Tanzania have been predominantly of asphaltic concrete construction. This ever enlarging and ageing asphaltic road network represents increasing resource requirements on the road agency in the form of maintenance. Limited resources coupled with the ever sky-rocketing costs of petroleum products and the competing demands of social economic developments, presupposes the need to look for alternative road construction technology that is more cost-effective and resource optimising. Experience gained from developed and some developing countries where concrete pavements have been widely used suggests the potential of this type of pavement in many developing countries. This paper discusses the technical …


Performance Of Aerobic Bioreactors During Treatment Of Tanning Industry Wastewater, Samwel V. Manyele Dec 2006

Performance Of Aerobic Bioreactors During Treatment Of Tanning Industry Wastewater, Samwel V. Manyele

Tanzania Journal of Engineering and Technology (TJET)

The performance of aerobic bioreactors loaded with novel biomass support (the KMT® support particles) during the treatment of tanning industry wastewater is presented in this paper. The wastewater samples were collected from TANWAT Company in Njombe, which extracts tannins from barks of the wattle tree. The wastewater generated from T ANWAT is very acidic with high loading of organic compounds, which are very complex and difficult to biodegrade using conventional methods. The paper introduces a new technology for treatment of heavily loaded industrial wastewater, like tannins, that is the Three-Phase Fluidized Bed Bioreactor (TPFBB) which utilizes the KM'f® support particles. …


An Intervention Framework Based On A Complementary Theory Of Organizational Decline, George S. Mwaluko Dec 2006

An Intervention Framework Based On A Complementary Theory Of Organizational Decline, George S. Mwaluko

Tanzania Journal of Engineering and Technology (TJET)

This paper has developed an intervention framework based a complementary theory Of Organization decline. Any management intervention effort is normally based on a certain theory of organizational decline i.e. a theory that explains the causes for failure of organizations. Four major theories Of Organisational decline were identified in the literature, reviewed and integrated into one, presumably more superior, theory of organisational decline. They included the natural selection theory, the resourc+based theory, the theory Of misperception of feed!mck and the contingency theory. The new theory was then used to guide the design of an intervention framework. The framework utas then used …


Investigation On Distribution Of Cast Properties On Aluminum Plates Poured By Side Gating Technique, Joseph Runyoro Dec 2006

Investigation On Distribution Of Cast Properties On Aluminum Plates Poured By Side Gating Technique, Joseph Runyoro

Tanzania Journal of Engineering and Technology (TJET)

Casting technologies wllich improve casting yield and intenzal sOllndness of thin wall cast components are of particular interest to industry especially for critical applications. The main aim of fOll1ldries is to achieve castings free from defects at low cost. It hils been thought that pouring casting by side ingate technique improve directional solidification as the metal stays hot for long time in the feeder cum ingate. Experiments were carried alit IIsing a side gating technique to cast a number of 300 mm x 300 mm LMO and LM 25 plates in furall and pepset sand moulds. The thickness used was …


Sampling Procedure For Pavement Condition Evaluation Of Local Collectors And Access Roads, David Mfinanga Dec 2006

Sampling Procedure For Pavement Condition Evaluation Of Local Collectors And Access Roads, David Mfinanga

Tanzania Journal of Engineering and Technology (TJET)

Road surface condition evaluation involves the collection Of a lof Of data on different types of distresses. •lie exercise consumes a lot Of resources if the whole road section length is sureeyed and may be prone to errors as a result Of surveyors' fatigue. It is therefore important Io develop n reprevntative sample to be used When road condition manually. This study aimed nt determining sample size for condition evaluation of local collector access roads in urban areas in Tanzania. Two such roads namely l.ufungira and Kilimahewn roads respectively were selected for the study. It is recommended that a section …


Towards Effective Online Learning Implementation In Tanzanian Higher Learning Institutions: Obstacles, Challenges And Opportunities, M Victor Dec 2006

Towards Effective Online Learning Implementation In Tanzanian Higher Learning Institutions: Obstacles, Challenges And Opportunities, M Victor

Tanzania Journal of Engineering and Technology (TJET)

This paper identifies and discusses several influential factors as well as opportunities, associated with effective- online learning implementation in Tanzanian Higher Learning Institutions (THUs). Fourteen (14) THUs were surveyed, using face-to-face interviews in focus groups. The groups included Lecturers, Heads of ICT Departments, ICT Technical Personnel as well as Admi/:listrative Staff. Results indicate that mostly, problems with effective online implementation in THUs are centred on a severe scarcity of online resources and tools and that the main challenges lie in going beyond the process of integrating technology with their teaching curricular, so that training of both teaching and supporting staffs …


Study On Vortex Formation In The Pouring Basin By Direct Observation, J Runyoro Jun 2006

Study On Vortex Formation In The Pouring Basin By Direct Observation, J Runyoro

Tanzania Journal of Engineering and Technology (TJET)

Although the formation of vortex on the free surface of liquid draining from a container is often observed, relatively little is known about the phenomenon. When a liquid is drained from a container such as a bathtub through a bottom orifice, a dip on the surface known as vortex is formed. The vortex first appears as a small dimple in the free surface, which suddenly forms a cone-shaped hole. The vortex causes turbulences, which draws in air down into the orifice (drain). Generally, the issue of vortex formation is so common in our lives that possibly its occurrence seems to …


Suitability Of Crusher-Dust As Masonry Construction Material, John Makunza Jun 2006

Suitability Of Crusher-Dust As Masonry Construction Material, John Makunza

Tanzania Journal of Engineering and Technology (TJET)

Crusher dust generated at Kunduchi quarries in Dar es Salaam during aggregate crushing is counted as a waste material, and some times it .is disposed away or sold at a cheap price of not more than a quarter of that of sand. A study on the use of the crusher dust as a building material has been carried out in which samples were collected and analyzed for grading (sieve analysis). In additional to that, other samples were stabilized with a small amount of cement, from which bricks were produced and tested for compressive strength. Other bricks were bonded together using …


Effectiveness Of Hot Isostatic Pressing On Healing Oxide Film Defects In Cast Aluminium Alloys, C Nyahumwa Jun 2006

Effectiveness Of Hot Isostatic Pressing On Healing Oxide Film Defects In Cast Aluminium Alloys, C Nyahumwa

Tanzania Journal of Engineering and Technology (TJET)

Hot isostatic pressing (hipping) of cast aluminium alloys is recognized as a means of providing improved internal soundness and mechanical properties of the castings. However, little is known about the limitations and potential benefit of the hipping process to produce reliable aluminium alloy castings containing oxide film defects due to turbulently filling of moulds. In this study, oxide film defects and fatigue lives of turbule''Zt filled unfiltered AI-7Si-Mg alloy castings have been characterised in as-cast and hipped. conditions to quantify the effectiveness of hot isostatic pressing on healing oxide film defects in the castings. The average fatigue life and fatigue …


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 …


Investigation Of The Stability Of Engine – Governor System Operated At Low Speeds, Cuthbert Mhilu Jun 2006

Investigation Of The Stability Of Engine – Governor System Operated At Low Speeds, Cuthbert Mhilu

Tanzania Journal of Engineering and Technology (TJET)

During diesel engine operation, a tendency for the engine not to achieve a  steady idling speed has often been observed. During idling speed the engine tends to either race or stall as a result of poor and incorrect metering of the fuel, which is required for the combustion process and if severe, the engine will stop firing completely. 111 this research an investigation was made to establish knowledge on diesel engine stability operated at low speeds. The influence of a governor of an engine in the control of the engine speeds has also been investigated. In order to obtain information …


Environmental Impact Of Wetland Resources Utilization In Simuyu Basin, Tanzania, Shadrack Mwakalila Jun 2006

Environmental Impact Of Wetland Resources Utilization In Simuyu Basin, Tanzania, Shadrack Mwakalila

Tanzania Journal of Engineering and Technology (TJET)

There is a growing appreciation of the natural functions of wetlands, and the values and different forms of uses that humans attach to them. Wise use and special conservation strategies are therefore needed in order to sustain their productivity. Wetlands are one of the most fruitful areas of archaeological research, and they are the ideal setting in which to study the interactions between physical processes and human actions that encapsulate and exemplify many of the themes of man's impact on his environment. But all these beneficial functions of wetlands seem to be in danger of being lost to draining and …


Earth Building In Tanzania - Use Of Soil Stabilized Bricks And Blocks, A Mrema Jun 2005

Earth Building In Tanzania - Use Of Soil Stabilized Bricks And Blocks, A Mrema

Tanzania Journal of Engineering and Technology (TJET)

This paper presents experimental results of investigations done on the use of stabilized earth (soil) for the manufacture of bricks and blocks. The soil used was clayey sand of low plasticity. Two types of stabilizers were used to make stabilized bricks and these were cement and a combination of cement and lime. Different stabilizer proportions were employed. Results of tests carried on these bricks at 28 days indicate an optimum mix proportion of 7% cement if cement is used alone and an optimum mix proportion of 5% each if a combination of lime and cement is used as a stabilizer. …


Study Of The Impact Of Quality Costs On Profitability: The Case Of Small And Medium Industries In Tanazania, B Kundi Jun 2005

Study Of The Impact Of Quality Costs On Profitability: The Case Of Small And Medium Industries In Tanazania, B Kundi

Tanzania Journal of Engineering and Technology (TJET)

No abstract provided.


Cement Oonded Wood Wool Board As A Building Material For Low Cost Housing, A Mrema Jun 2005

Cement Oonded Wood Wool Board As A Building Material For Low Cost Housing, A Mrema

Tanzania Journal of Engineering and Technology (TJET)

This paper gives results of a preliminary study on the properties of cement bonded wood-wool boards manufactured as composites by using wood-wool (excelsior) from podocarpus spp wood species and ordinary Portland cement. Two main parameters were varied during the investigation and these were the width of the wood-wool and the cement to wood-wool ratio. Results show that the optimum mix proportion is three parts of cement to two parts of wood-wool by weight and that a smaller excelsior width gives higher board strengths. The results from tests on flexural strength, compressive strength and tensile strength far exceeded the requirements of …


Low Cost Slab Manufactured From Masonry Slab Elements, John Makunza Jun 2005

Low Cost Slab Manufactured From Masonry Slab Elements, John Makunza

Tanzania Journal of Engineering and Technology (TJET)

The construction of bungalow houses requires sufficient space to accommodate all the requirements as per the client’s wish. The idea of low-rise or high rise buildings is very remote for most of the people due to the high costs of construction involved. Much of the said cost is due to the concrete floor slab as it consumes a bigger portion of concrete material when compared to beams and columns. In this paper, a study presented is on a new form of voided slab constructed from masonry slab elements that do not utilize formwork and consumes less concrete material. The slab …


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 …


Usefulness Of Technology Life Cycle In Tanzania: The Case Of The Ipl Developed Technologies, Abdallah Chungu Dec 2004

Usefulness Of Technology Life Cycle In Tanzania: The Case Of The Ipl Developed Technologies, Abdallah Chungu

Tanzania Journal of Engineering and Technology (TJET)

This study sought to identify the adoption rate of technologv innovations developed by the Institute Of Production Innovation (IPI) at the University Of Dar-es-Salaam since 1984 to 1997 using a sigmoid shaped curve (S-shaped curves) to predict the life cycles of the respective technologies. Depending on the stimuli imparted to the specific technology, some of such technologies for instance, cinva ram and block making machines with hollow/spacer/louver exhibited longer life period as indicated by a series Of infer-connected S-curves. Other technologies including but nor limited to sunflower oil processing kit-winnowers, scorcher with one stove, seed roller, standard wheelbarrow, and manual …


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.


Introduction Of Seismic Resistance Features In The Construction Of Buildings In Tanzania, I Rubaratuka Jun 2004

Introduction Of Seismic Resistance Features In The Construction Of Buildings In Tanzania, I Rubaratuka

Tanzania Journal of Engineering and Technology (TJET)

Available dara indicates that a greater part of Tanzania lies within a seismic region. to date most Of the buildings in the country have been designed and constructed without considering seismic loads. In addition no design codes have been developed to guide the seismic design for buildings and other related structures in Tanzania. This paper outlines the basic design concepts, which are useful during the design of seismic resistant buildings before the seismic design code is developed and adopted in Tanzania.


Importance Of Structural Fire Protection In Reinforced Concrete Buildings: A Case Study Of Ex-Nasaco Building In Dar Es Salaam, I Rubaratuka Jun 2004

Importance Of Structural Fire Protection In Reinforced Concrete Buildings: A Case Study Of Ex-Nasaco Building In Dar Es Salaam, I Rubaratuka

Tanzania Journal of Engineering and Technology (TJET)

Reinforced concrete is concrete that is internally reinforced with steel bars or mesh. This gives rhe malerial the compressive strength of concrete along wilh the tensile strength Of steel. Reinforced concrete does not perform well under fire conditions as it spalls and loses strength. Heating Causes a failure Of the bond between concrele and sleels bars and this results in reduction of strength of concrele. Strength of concrete decreases With increase in temperature and increase With time. In order to provide fire resistance to structural components/elements in buildings, it is important Io consider the type of aggregates to be used. …


A Study Into Lack Of Product Innovation And Business Techniques At The Tricycle Workshop And Rrs Lessons To Small Companies, E Elias Jun 2001

A Study Into Lack Of Product Innovation And Business Techniques At The Tricycle Workshop And Rrs Lessons To Small Companies, E Elias

Tanzania Journal of Engineering and Technology (TJET)

A study was carried out at the Tricycle Workshop (TW) which was facing the problem of !ack of orders and therefore stagnation Of business. The objective of the study was to find out reasons for this situation and to propose possible remedial solutions. The study was conducted using the principles of the Product Innovation process where internal and external issues related to the business Of the company were investigated for information. Analysis Of information obtained indicated that the bad situation of the TW had mainly been caused by the nature of the tricycles-supply system whereby users (disabled persons) are unable …


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 …


Trends Of Microcomputer Technology In Developing Countries, With More Focus On Tanzanian Experiences: Achievements And Problems, Satoki Mahenge Jun 1998

Trends Of Microcomputer Technology In Developing Countries, With More Focus On Tanzanian Experiences: Achievements And Problems, Satoki Mahenge

Tanzania Journal of Engineering and Technology (TJET)

Trends of microcomputer technology in developing countries, including Tanzanian. is like a 'mixed bag' of achievement and problems. Although rhe technology has been available for many years in developed world, developing countries are responding to it differently due to differences in political and economic policies. Some countries have acrimonious policies on the technology, some not. There are countries which utilize fully the technology in work places and others are still at dilemma on the importation of the technology due to what is 'claimed to be a weak economy in the presence Of many other pressing needs'. Other countries seem to …


Suitability Of The Present Strategic Information Technology Planning (Sitp) Methodologies To The Developing Countries, A Victor Jun 1994

Suitability Of The Present Strategic Information Technology Planning (Sitp) Methodologies To The Developing Countries, A Victor

Tanzania Journal of Engineering and Technology (TJET)

The needfor strategy formulation, or in general terms strategic planning, for IT is considered as one of the most important aspects of IT manage- ment. To this end, there are a number of IT strategy formulation method- ologies world-wide. These methodologies were developed over a span of time, starting from mid 1960's when IT use started to become a serious issue in the developed countries, and continued with the trends in IT de- velopment and use, as was applicable in those countries. Morc recent of the methodologies were developed through improvements on earlier ones, and based on the new challenges …