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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 …


Modelling The Impact Of Urbanization On Groundwater Using System Dynamic Technique. A Case Study Of Arusha Municipal Well Field In Northeastern Tanzania, Nimzihirwa Kashimbiri Dec 2009

Modelling The Impact Of Urbanization On Groundwater Using System Dynamic Technique. A Case Study Of Arusha Municipal Well Field In Northeastern Tanzania, Nimzihirwa Kashimbiri

Tanzania Journal of Engineering and Technology (TJET)

This paper is concerned with the impact of urbanization in aquifer well-system located in the Municipal area of Arusha city, Tanzania. A system dynamic (SD) model was built under VENSIM PLE workbench from twenty-five years (1978-2003) physical and non-physical data to simulate their interactions and relations. This involved use of mathematics ideas and concepts in studying the physical and non – physical components separately, and finally putting them together in new form (model) and study their relations. After model was found to be structurally complete and simulate properly by using the model and unit check tool of VENSIMPLE, parametric calibration …


Auditing Of Traffic Signs And Road Markings In Dar Es Salaam City, Hannibal Bwire Jun 2009

Auditing Of Traffic Signs And Road Markings In Dar Es Salaam City, Hannibal Bwire

Tanzania Journal of Engineering and Technology (TJET)

This study examines the efficacy of the traffic signs and road markings in Dar es Salaam City. The study focuses on the availability and conditions of traffic signs and road markings in some selected roads in the city. Auditing of traffic signs and road markings is carried out as one of the means of promoting road safety and improving road capacity in the city. The auditing procedure involved field studies through the use of traffic signs/markings checklists and ranking of road stretches according to the availability and conditions of traffic signs observed for improvement prioritization in case of financial constraints. …


The “Tea Cup Effect” And Removal Of Suspended Solids From Water, D.A. Mashauri Jun 2009

The “Tea Cup Effect” And Removal Of Suspended Solids From Water, D.A. Mashauri

Tanzania Journal of Engineering and Technology (TJET)

Suspended solids problem in water is an issue as old as water treatment itself. Suspended solids can be causative to eroding through abrasion of impellers, pump casings, pipes and other water works related appurtenances. It is therefore appropriate that suspended solids must be removed as early as possible in the water works treatment facilities. It is usually done at the river/lake intakes to reduce the coarse particulate matter that would otherwise adversely affect the water works thereafter. The fine particles that will escape the entrapment at the intake works would therefore require further and more effective system that would remove …


Parametric Study Of Stimulus-Response Behavior Incorporating Vehicle Heterogeneity In Car-Following Models, Saidi Siuhi Jan 2009

Parametric Study Of Stimulus-Response Behavior Incorporating Vehicle Heterogeneity In Car-Following Models, Saidi Siuhi

UNLV Theses, Dissertations, Professional Papers, and Capstones

The objective of this study was to develop a family of car-following models that address the shortcomings of car-following models developed by General Motors (GM) in the 1950s. The developed models consist of separate models for acceleration, deceleration, and steady-state responses for congested freeway traffic conditions. The study calibrated the models using individual vehicle trajectory data collected on a segment of Interstate 101 in Los Angeles, California. Furthermore, the study validated the models using individual vehicle trajectory data collected on a segment of Interstate 80 in Emeryville, California. The study used nonlinear regression with robust standard errors to estimate the …


Improving The Design Of Low Volume Sealed Roads In Tanzania, Mfinanga A Dec 2008

Improving The Design Of Low Volume Sealed Roads In Tanzania, Mfinanga A

Tanzania Journal of Engineering and Technology (TJET)

The main objective of the study was to identify appropriate road designs for Low Volume Sealed Roads (LVSRs) with the aim of improving the design of such roads in Tanzania. The study was conducted in Dar es Salaam and Morogoro regions in Tanzania where data for LVSRs were collected from primary and secondary sources in the two regions. The study found that by using an improved pavement design method specifically meant for LVSRs results in cost savings for LVSRs of up to 51% compared with the conventional method of pavement design in Tanzania. The study recommends that the pavement design …


Integrated Remote Sensing And Gis Techniques For Groundwater Exploration In Semi-Arid Region: A Case Of Karamoja Region – Uganda, Lubang Nobert Dec 2008

Integrated Remote Sensing And Gis Techniques For Groundwater Exploration In Semi-Arid Region: A Case Of Karamoja Region – Uganda, Lubang Nobert

Tanzania Journal of Engineering and Technology (TJET)

Groundwater is a precious resource that covers wide geographical extent. Proper evaluation is required in order to ensure prudent use of groundwater resources. The current groundwater assessment in Karamoja region, as in many parts of the world, uses Apparent Resistivity and Vertical Electrical Sounding, which has limited coverage to some localized usually predetermined areas. Comprehensive groundwater development program needs a wide area coverage and large volume of multidisciplinary data. In the present study, an integrated remote sensing and GIS based methodology is developed and tested for the evaluation of groundwater resources of Karamoja Sub Region, Northeastern Uganda. The components of …


Potential Use Of Waterguard As A Disinfectant For Domestic Water Use, Yohana L Dec 2008

Potential Use Of Waterguard As A Disinfectant For Domestic Water Use, Yohana L

Tanzania Journal of Engineering and Technology (TJET)

been identified as an alternative method for treatment of domestic drinking water. The aim of this study was to investigate the effectiveness of Water Guard in disinfecting drinking water from different sources drawn from Kinondoni district, Dar es Salaam as well as to establish appropriate dosage that can be used during the treatment. Results showed that, a dose of 4.0mL per 20 litrer of water guard is sufficient for disinfection of urban water sources. The above prescribed doses provide 100% disinfection efficiency with residue chlorine of less than 0.3mg/l. Water with turbidity values of 30-35 NTU, chlorine dosage of 8mL/20 …


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 …


An Equation For Estimating The (R) Usle Slope Steepness Factors, Mathew Mulemgera Dec 2008

An Equation For Estimating The (R) Usle Slope Steepness Factors, Mathew Mulemgera

Tanzania Journal of Engineering and Technology (TJET)

Abstract Currently three equations are used for calculating slope steepness factor for the Revised Universal Soil Loss Equation (RUSLE); one for slopes less than nine percent, the second for slopes equal or greater than nine percent, and the third equation that has been proposed for use in China for slopes equal or greater than 17 %. The three equations have linear relationships between slope steepness factor, S and the sine of the slope angle, θ. The three equations under predict the factor, S when used on slope steepness beyond the data sets used to develop them. In addressing this problem …


Trends Of Rainfall And Maize Productivity In Malawi, T Kimaro Jun 2008

Trends Of Rainfall And Maize Productivity In Malawi, T Kimaro

Tanzania Journal of Engineering and Technology (TJET)

Daily rainfall data between 1966 and 2005 across all Agricultural Development Areas (ADDs) in Malawi was investigated to determine changes in selected rainfall characteristics and their impact on Maize productivity. Rainfall indices analyzed included rainfall amounts (annual and seasonal), onset, cessation, dry spells and length of rainy season. Man Kendal’s trend test was applied to the time series of these indices to detect any trends in the time series. Water Requirement Satisfaction Index (WRSI) for maize crop was used to study the spatial-temporal variation of maize productivity and thus its linkage to rainfall. Definition of onset and cessation adopted from …


The Limnogeology Of The Lakes Sagara And Nyamagoma, Hudson Nkotagu Jun 2008

The Limnogeology Of The Lakes Sagara And Nyamagoma, Hudson Nkotagu

Tanzania Journal of Engineering and Technology (TJET)

The present study focuses on the limnogeological aspects of the lakes Sagara and Nyamagoma within the Malagarasi Wetland Ecosystem. Abiotic parameters from water and sediment samples were determined during the dry and wet seasons using appropriate gears and methods. The data show variation of the abiotic parameters in both lakes from the water surface to the bottom. Lake Nyamagoma is less turbid (0.7-24 NTU) than Lake Sagara (25 to 65 NTU). The water transparency was also high at Lake Nyamagoma (0.75-1.5 m) thus supporting the observed turbidity trend. The physical chemical changes may be attributed to processes such as cooling, …


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 …


Assessment Of Integrated Water Resources Management Practice In Yatta Canal, Machakos District, Kenya, Lawrence Simitu Jun 2008

Assessment Of Integrated Water Resources Management Practice In Yatta Canal, Machakos District, Kenya, Lawrence Simitu

Tanzania Journal of Engineering and Technology (TJET)

Yatta Canal is situated in Yatta division, Machakos district about 100 km from Nairobi along Thika- Garissa road. It is about 60 Km long and supplies water for domestic, livestock and irrigation use. Over the years, the water supply has been unreliable especially during dry season leading to conflicts between upstream and downstream consumers. Sometimes the Government has been forced to intervene to restore order. The study aimed at assessing the use of Yatta canal, based on the principles of Integrated Water Resources Management (IWRM) which stipulates efficient use of water and involvement of all stakeholders in decision making for …


Sediment Yield Prediction In Tanzania: Case Study Of Dodoma District Catchments, Mathew Mulemgera Jun 2008

Sediment Yield Prediction In Tanzania: Case Study Of Dodoma District Catchments, Mathew Mulemgera

Tanzania Journal of Engineering and Technology (TJET)

Soil erosion and sedimentation is serious and is resulting in rapid sedimentation of streams and reservoirs in Tanzania. This makes sediment yield modeling important before undertaking water resources development projects, although it has so far not been done in the country. At present sediment yield prediction can be done using physically based models, empirical soil erosion and sediment yield models, and sediment rating curves. The physically based models contain numerous parameters that are difficult to measure or estimate, making them inappropriate in developing countries like Tanzania. The rating curves give rough estimates while the empirical sediment yield models need runoff …


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.


Sedimentation Status Of Lake Victoria: Loading From River Mouth And In-Lake Sedimentation, F Mwanuzi1 Jun 2008

Sedimentation Status Of Lake Victoria: Loading From River Mouth And In-Lake Sedimentation, F Mwanuzi1

Tanzania Journal of Engineering and Technology (TJET)

Lake sediments consist of the input of suspended solids by river discharges, the autochthonous produced particulate matter in the water column and the settled material on the lake bottom. The loading, transport, formation and decay of the sediments entering the Lake Victoria from Tanzanian side was monitored for the period 2000 to 2005. The sedimentation study focused on; quantification of settling fluxes of particulate nutrients and organic carbon at the off shore(Pelagic) and near-shore(Littoral) monitoring stations. Monitored data on sedimentation rate and settling velocities has been sampled and analysed in the period November 2000 to March 2005. The mean sedimentation …


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 …


Nyumba Ya Mungu Reservoir System Simulation By Using Hec-Ressim Model, Deogratias Mulungu Jun 2007

Nyumba Ya Mungu Reservoir System Simulation By Using Hec-Ressim Model, Deogratias Mulungu

Tanzania Journal of Engineering and Technology (TJET)

This research paper focused on estimating effective water and optimization of the NyM reservoir for storage conservation and hydropower generation. Several models were used in the study: the Rainfall-Runoff model, GFFS was used to fill in missing data, and the HEC-ResSim Model and the NWBM for reservoir system simulation and water balance respectively. The effective inflows to the NyM reservoir were determined using HEC-ResSim model and the NWBM used to check the total water loss in the system. For the reservoir system simulation, the HEC-ResSim model was used to estimate water loss through irrigation abstractions in Kikuletwa and Ruvu reaches …


Socio-Economic Impacts Of Water Scarcity In Dar Es Salaam, Tanzania, Shadrack Mwakalila Jun 2007

Socio-Economic Impacts Of Water Scarcity In Dar Es Salaam, Tanzania, Shadrack Mwakalila

Tanzania Journal of Engineering and Technology (TJET)

Drought and the resulting low water levels in rivers exacerbate water scarcity conditions in Dar es Salaam city. The result is frequent water rationing in areas served with piped water, sometimes for days or weeks, and low water pressure, which leads residents to resort to other less safe and sometimes more expensive water sources. The frequent and current response to the inadequate piped water supply in Dar es Salaam has been the use of groundwater resources. There are both public and private bore-holes and wells drilling companies in Dar es Salaam.. This paper therefore, presents some socio-economic impacts of water …


Program For The Analysis Of Plane Trusses, John Makunza Jun 2007

Program For The Analysis Of Plane Trusses, John Makunza

Tanzania Journal of Engineering and Technology (TJET)

The ‘TRAP - TRuss Analysis Program’ can assist engineers in the analysis of plane truss-type structures, as well as prove an excellent basis for understanding the “finite – element” method. The Program is completely menu-driven, with all nodes, elements, and load data entered through an input file. TRAP includes plotting for displaying the truss geometry in its original shape showing all nodes and support points. In the analysis process, firstly the structure data; e.g number of nodes, elements, materials and supports are to be defined. Secondly, element properties and support constraints have to be specified. Finally, nodal global loads are …


Optimal Utilization Of Timber Poles As Structural Members Of Formwork, Ladislaus Lwambuka Jun 2007

Optimal Utilization Of Timber Poles As Structural Members Of Formwork, Ladislaus Lwambuka

Tanzania Journal of Engineering and Technology (TJET)

Timber poles of the type “Mirunda” are commonly used in East Africa as formwork support structures for casting of reinforced concrete slabs, beams and canopies. It is also widely known that the “Mirunda” poles as structural members of formwork are massively used without any structural consideration and guidance. This common practice has resulted into wastage of natural resources and escalated construction costs. This study has attempted to establish the load bearing capacity of randomly selected “Mirunda” poles through laboratory testing. Using an existing construction site as a case study, the results have been used to establish the actual number of …


Preliminary Estimates Of Building Cost And The Lowest Evaluated Tender, Harriet Eliufoo Jun 2007

Preliminary Estimates Of Building Cost And The Lowest Evaluated Tender, Harriet Eliufoo

Tanzania Journal of Engineering and Technology (TJET)

The paper has investigated and established to what extent are preliminary estimates of building costs close to the lowest evaluated tender and how geographical proximity influences the variance between preliminary estimate and the lowest evaluated tender. A multiple case study constituting 43 building projects in Tanzania were statistically analysed covering a period from 1995- 1999. Findings reveal a significant variance exists between the quantity surveyor’s preliminary estimate figure and the lowest evaluated tender; and that the variance between the quantity surveyor’s figure and the bidder is small when the proposed building project is geographically closer to the quantity surveyor’s base. …


Characterization Of On-Road Petrol Vehicle Emissions Patterns In Dar Es Salaam City (Tanzania), Geoffrey John Dec 2006

Characterization Of On-Road Petrol Vehicle Emissions Patterns In Dar Es Salaam City (Tanzania), Geoffrey John

Tanzania Journal of Engineering and Technology (TJET)

Motor vehicle emissions have been identified to be the major source of air pollution in most urban cities. It has serious impact on urban air quality and public health. The Governments of many countries need to adopt stringent vehicle emissions regulations to protect the air quality, the undertaking of which can only be implemented once the problem at hand is known. In the present study, the characteristics of on road vehicle emissions from the selected local ar~as at the city of Dar es Salaam in a developing country for in-use petrol vehicles for urban driving conditions ranging from idling, lOkm/h …


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 …


Determination Of Wind Loads Causing Flutter Effects, Ladislaus Lwambuka Dec 2006

Determination Of Wind Loads Causing Flutter Effects, Ladislaus Lwambuka

Tanzania Journal of Engineering and Technology (TJET)

A new method on the determination Of wind forces by experimental means in a wind tunnel is discussed. The method reported herein is based on the identification methodology Of model parameters under time response (i.e. time domain identification). As a test model, a thin plate Of Cypress wood, elasticully suspended in three degrees Of freedom to represent the idealized form of a classical airfoil, for Which theoretical wind load parameters exist, has been employed. Wind load parameters, experimentally obtained on the test model under the new method, are compared With the theoretical values of classical airfoils. Advantages of the new …


Impact Of Institutional Framework On Wetland Management In Tanzania, Shadrack Mwakalila Dec 2006

Impact Of Institutional Framework On Wetland Management In Tanzania, Shadrack Mwakalila

Tanzania Journal of Engineering and Technology (TJET)

Wetland loss continues today despite fhe existence of institutions With a specific mandate to manage uvtlands in Tanzania. In reviewing this apparent contradiction, this paper Soes in depth to explore the existing sectors associated with the development and management Of wetlands in the Country. Specifically it focuses on institutional framework a: Village level, Ward level, District level and national level. Among the key sectors consulted includes; agriculture and livestock, wildlife, forestry, fisheries, t'üier resources, lands, minerals and energy. The interest While visiting them was aiming at exploring the existing opportunity With regard to the tulues of the wetlands and their …


Dar Es Salaam Water Supply Problems And Possible Solutions: Reflections, D Mashauri Dec 2006

Dar Es Salaam Water Supply Problems And Possible Solutions: Reflections, D Mashauri

Tanzania Journal of Engineering and Technology (TJET)

During the assessment of the manuscript, it was observed that the paper does not include an abstract. The document proceeds directry to the main content without providing a separate abstract that summarize the study's objectives, methodology, key findings and conclusions


Geophysical Exploration For Groundwater Resources Potential Over Basement Formations At Kwandolwa And Mwisho Wa Shamba Villages, Korogwe District, Tanzania, Cuthbert Mhilu Dec 2006

Geophysical Exploration For Groundwater Resources Potential Over Basement Formations At Kwandolwa And Mwisho Wa Shamba Villages, Korogwe District, Tanzania, Cuthbert Mhilu

Tanzania Journal of Engineering and Technology (TJET)

In this paper results of geophysical exploration studies to identify potential areas with groundwater resources at Kwamndolwa and Mwisho wa Shamba Villages in Korogwe District have been presented. The resistivity curves of eight sites at the two study areas were obtained using field data measurements made based on the application of a vertical electrical sounding (VES) method. The resisivity values obtained for sites VES-K3 and VES-M2 were found to be 10.9 and 24.0 ohm-m respectively. The interpretation of the resisivity values made for the two sites gave also an indication of the presence of sedimentary rocks composed of sandstone materials …


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 …