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- ACCURACY ANALYSIS FOR KOLMOGOROV ENTROPY USED IN STUDYING THE CHAOTIC DYNAMICS OF CFB REACTORS BASED ON SOLIDS CONCENTRATION FLUCTUATIONS (1)
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Articles 121 - 150 of 155
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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.
Derivation And Analysis Of Maximum And Conditional Work Of An Electromagnet In Relays With Small Gaps And Constant Armature Load, Dominic Chambega
Derivation And Analysis Of Maximum And Conditional Work Of An Electromagnet In Relays With Small Gaps And Constant Armature Load, Dominic Chambega
Tanzania Journal of Engineering and Technology (TJET)
No abstract provided.
Mathematical Simulation Of The Influence Of Volatile Ma•Rrer Cloud On Heterogeneous Ignition Of Single Coal Particles, Hassan Ratal Ambula
Mathematical Simulation Of The Influence Of Volatile Ma•Rrer Cloud On Heterogeneous Ignition Of Single Coal Particles, Hassan Ratal Ambula
Tanzania Journal of Engineering and Technology (TJET)
Asimple model has been developed to predict the heterogeneous ignition temperature for single coal particles under conditions of negligible, natural and forced convections. These conditions cause different sizes Of volatile matter cloud that surround the coal particle. The model is based on the ignition Of a single coal particle heated by irradiation from spot heaters in a cold (ambient) surrounding. Energy from the particle surface oxidation, volatile matter combustion and physical heating from the spot heaters are all included in rhe particle energv balance. General ignüion criterion is used to determine the ignition point. The agreement between the experimental and …
Probabilistic Load Flow For Mv Radial Distribution Networks Supplying Statistical Loads, B Kundy
Probabilistic Load Flow For Mv Radial Distribution Networks Supplying Statistical Loads, B Kundy
Tanzania Journal of Engineering and Technology (TJET)
Aecurate load models are required Jör 'he computation OJ' load on Medium Voltage (MV) distribution net•.vovk.s_ Modern microprocessors in recent times have enabled researchers stunple and log domestic loads. The findings show that domestic loads are stochastic in nonwe and are best described bv u beta probability distribution [Herman et al. 1999]. The statistical evaluafion lhe consumer voltages requires description load currents al rhe lime e/ lhe system maximum demand. In this paper. an analytical 1001 computing voltage vegulation on MV distribution net-norks fi•eding statistical louds is presenled. To deal beta- distributed currents on MV distribution networks, new scaling factors …
Baseflow Separation Based On Storage-Outflow Modelling Of Streamflow Recessions, With Application To Semi- Arid Catchments In Tanzania, S Mwakalila
Tanzania Journal of Engineering and Technology (TJET)
Discharge in many rivers is Often fed by baseflow provided by drainage of the saturated zone in the shallow permeable soils. It is becoming clear that the outflow from this saturated zone is not linear proportional to storage as is commonly assumed in many algorithms. The objectives Of this study theretore, are first to explore the extent to which the assumption of linearity in storage-outflow relationships is valid and secondly to introduce an alternative approach to baseflow separation algorithms for estimating direct mnoff time series. Numerical analysis Of streamflow recessions from the semi-arid catchments of the Great Ruaha basin in …
Electrokinetic Cha Raci'erisation Of Colloidal A-Alumina, J Ntalikwa
Electrokinetic Cha Raci'erisation Of Colloidal A-Alumina, J Ntalikwa
Tanzania Journal of Engineering and Technology (TJET)
Electrophoretic mobility (uD is an important rneasurable parameter in studying the electrokinetic properties of a colloid dispersion. This parameter is Often convened into zeta potential (C) Which piays a great role in thc description Of the stability towards aggregation Of dispersed particles. In this paper, measurements of Of colloidal a-alumina dispersed in various concentrations of electrolyte arc reported. It was observed that, the isoelectric points (the pH at which us = O) occurred at 7.52 ± 0.32, 8.05 ± 0.11 and 7,95 ± 0.18 in Naci, KCI and NaNOs respectively. The isoelectric point was observed to be a function Of …
Comparative Analysis Of Rng K-E And 'Standard' K-C Models For Fluid Flow Around A Cylinder, A Temu
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 …
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 …
Mathematical Modelling Of Road Bumps, E. S. Massawe
Mathematical Modelling Of Road Bumps, E. S. Massawe
Tanzania Journal of Engineering and Technology (TJET)
In this paper, a general mathematical model that may be used for construction of a road bump on an inclined road is developed. It is shown that if the parameters for the inclination are set to zero, the resulting model reflects the special case of a flat road. Existing experiences are briefly highlighted and a case study was done on different locations along the University Road to demonstrate the developed model.
Tracking The Trochoid On Safari, Andrew Simoson
Tracking The Trochoid On Safari, Andrew Simoson
ACMS Conference Proceedings 1999
While on sabbatical in Dar es Salaam in 1997–98, I was tasked to be the department’s seminar director and discovered that a dearth of speakers roam about in east Africa; so I opted to set up a lecture tour for myself to include Zambia, Zimbabwe, and Botswana as well as Tanzania—and spoke about the envelope of curves generated by a series of line segments obtained when two runners attached by an ideal bungee cord (the line segments) proceed about a circular track. Herein we describe life in east Africa and show that those envelopes are trochoids.
Estimating The Usle - Soil Erodibility Factor In Developing Tropical Countries:A Case Study In Tanzania, Metthew Mulengeral
Estimating The Usle - Soil Erodibility Factor In Developing Tropical Countries:A Case Study In Tanzania, Metthew Mulengeral
Tanzania Journal of Engineering and Technology (TJET)
Developing countries in the tropics are facing more soil erosion problems than the developed temperate countries. These developing countries have no accurate locally applicable equation(s) for predicting soil erosion or for planning and implementation of soil conservation measures. Furthermore, These countries do not have the necessary resources to develop the soil loss prediction equation(s). Existing empirical equations like the Universal Soil Loss Equation (USLE) if modified to suit tropical conditions can be useful a tool in soil erosion control in the region for a foreseeable future. In this paper equations'for estimating the soil erodibility factor in the USLE for tropical …
A Comparison Of Three Numerical Methods Of Solutions Of Equations Describing Unsteady Gas Flow At Pipe Boundaries In Reciprocating Compressor Systems, M Mkumbwa
Tanzania Journal of Engineering and Technology (TJET)
A number of finite difference schemes are available to study pressure fluctuation effects in unsteady pipe flows. This paper presents a comparison Of the predictions made by three such schemes of unsteadyjlow effects in a number of reciprocating compressor pipe-work systems. The finite difference schemes considered were;- a first order scheme known as the method Of characteristics, two second order schemes which were the Leapfrog method and MacCormacVs method. A reciprocating compressor simulation computer program was coupled with equations describing the cylinder thermodynamic processes with the pipe flow equations for steady non-homentropicflow. The comparison presented takes into account both the …
Turbulent Burning Model For Premixed Gaseous Mixtures, E Mushi
Turbulent Burning Model For Premixed Gaseous Mixtures, E Mushi
Tanzania Journal of Engineering and Technology (TJET)
A turbulent burning model for premixed gaseous mixtures has been successfully developed. The model assumes instant burning of vortex Tubes of the order of Kolmogorov scale followed by burning of larger eddies of the order of Taylor micro scale. These eddies burn ar a rate dependent On the stretch rate. The influence of turbulence on the burning rate is introduced in the form of probability density function which gives the probability that a given mixture under turbulence will undergo burning rather than being quenched. The model has been validated againsi experiments involving turbulent explosions in a fan stirred bomb. Model …
Extracting Consistent Weight Ratio Matrices From Inconsistent Judgement Matrices., Christian Alphonce
Extracting Consistent Weight Ratio Matrices From Inconsistent Judgement Matrices., Christian Alphonce
Tanzania Journal of Engineering and Technology (TJET)
The Analy,'ic Hierarchy Process (AHP) developed by Saaty Inore (han a decade ago has been widely applied in diverse decision making problenls ranging from socio-economic planning to engineering designs. One of the basic steps of this popular decision support tool is concerned with estimating a ratio scale of a set of entities from their inconsistent pairwise comparison judgement matrix. A number of estimation procedures for this purpose have been proposed. These include Saaty's eigenvector meihod, various geometric means methods, and methods using logarithmic least squares, least squares. and means Transformanons, amongst O,'hers. One Thing conunon to all these Inethods is …
Analysis Of The Analytic Hierarchy Process Methodologies, C B Alphonce, C M. Brugha
Analysis Of The Analytic Hierarchy Process Methodologies, C B Alphonce, C M. Brugha
Tanzania Journal of Science
We review various methodologies for estimating the impact scores of alternatives on criteria within the Analytic Hierarchy Process (AHP). The results show that the geometric mean method for retrieving impact scores from judgment matrices and the weighted geometric mean aggregation rule provide a best fit to the underlying structure of the problem.
Development And Evaluation Of A New Soil Erosion- Productivity Index Model (Sepim), Metthew Mulengera
Development And Evaluation Of A New Soil Erosion- Productivity Index Model (Sepim), Metthew Mulengera
Tanzania Journal of Engineering and Technology (TJET)
A soil erosion-productivity model which considers rhe effect of soil water storage Capacity. crop evapotranspiration, soil chemical and physical properties inrporrantfor Crop growth has been developed. The model is shown to give good predictions and it promises to be an improvement over the former productivity Index (PI). It also promises to give more reliable results than the currently used /nodels which consider only soil water storage capacity and crop e ' 'apotransp iration.
Model For Complete Drawdown Of Floating Solids In Stirred Tank Reactors, J Mmbaga
Model For Complete Drawdown Of Floating Solids In Stirred Tank Reactors, J Mmbaga
Tanzania Journal of Engineering and Technology (TJET)
A Semi-empirical model has been developed on the basis of Kolmogoroff's theory of isotropic turbulence to determine the minimum drawdown speed for floating solids in a mechanically agitated vessel. An adjustable pa- rameter in the model is found to be afunction of impeller type and position in a vessel. A simplified representation of macroscopicflow pattern, rep- resenting the circulation flow in a vessel depending on impeller pumping characteristic is developed to account for recirculation pattern.
Optimum Geometrical Parameters For Prismatic Folded Plate Roofs: System- Atic Search Approach, N Mwitta
Optimum Geometrical Parameters For Prismatic Folded Plate Roofs: System- Atic Search Approach, N Mwitta
Tanzania Journal of Engineering and Technology (TJET)
Folded plate structures have unique structural advantages over conven- nonal beam-and-slab structural forms. Selection of optimum geometrical parameters in design would make folded plate roofs more appealing to the national construction industry in terms ofcost. This paper presents a study on shape optimization of prismatic folded plate roofs for minimum weight of the structure per unit covered area. A computer based systematic search approach has been employed.for the optimization study, while the tranyeer matrix method has been used for analysis. Curves opriinum geometrical parameters versus span have been pre sented for three commonly used shapes of prismatic folded plate roofs. …
Regionalization Of Hydrologic Information In Tanzania (Low Flows), Onyekwuluje C
Regionalization Of Hydrologic Information In Tanzania (Low Flows), Onyekwuluje C
Tanzania Journal of Engineering and Technology (TJET)
Hydrologic infornjation is required for the planning and design Ofwater resource projects. However, Hydrologic infonnation is always lacking at points of interest. Regionalization is ained at estimating hydrologic infor- mation such as low flow statistics at ungauged sites. Hydrologic informa- tion from 63 catchments in Tanzania has been analysed. In this paper, pooled flow duration curves for 1, IO, 30, 60, and 90 days duration have been established. Regression equations between the low flow indices (i.e. 95 percentile and for a IO day duration, average annual yield (AAY), av- erage daily flow (ADE)) and catchment characteristics were developed. The pooled …
Influence Of Turbulence On Methane-Air Flame Speed, E Mushi
Influence Of Turbulence On Methane-Air Flame Speed, E Mushi
Tanzania Journal of Engineering and Technology (TJET)
Experimental study Of the influence qfturbulence on flame speed for meth- ane-air mixtures has been conducted in afan stirred bomb using schlieren photography. It has been observed that turbulence increases flame speed but above KLe=O. 18 (KLe is the product Of the dimensionless Karlovitz flame stretch factor and the Lewis number) turbulence quenches the flame. Inminarflame kernel is observed to prevail in the early stages of flame development in a turbulent mixture. Further, the laminar burning velocity plays a significant role in turbulent combustion. It is proposed that the increase in flame speed is a result of flame wrinkling.
A Conceptual Approach To Water Resources Management For A Catchment In Tanzania, F Mwanuzi
A Conceptual Approach To Water Resources Management For A Catchment In Tanzania, F Mwanuzi
Tanzania Journal of Engineering and Technology (TJET)
In hydrology/Water resources, normally rainfall data are available for longer periods than runoff data. Many attempts have been made to extend these runoff data by using system approach and conceptual models. The conceptual approach to simulate runoff at the outlet ofa catchment is based on the physical processes involved in the transformation of rainfall into runoff (river flow). In this paper a conceptual model, (SEAMOD) has been used. This model has a limited number of parameters to optimize when compared to other models like the sacramental model. Also it requires less input data. The model assumes that the storage is …
A Check Parameter Method For Use In Designing Relays, H Kadete
A Check Parameter Method For Use In Designing Relays, H Kadete
Tanzania Journal of Engineering and Technology (TJET)
Low quality magnetic steel available locally has been successfully used as core material for a relay. New design principles as well as construction procedure used in development of a prototype are presented. Then the new approach is assessed and found to deliver acceptable accuracy.
Mathematical Analysis Of Marketing Costs Of Agricultural Crops: The Case Of Coffee, C.B. Alphonce
Mathematical Analysis Of Marketing Costs Of Agricultural Crops: The Case Of Coffee, C.B. Alphonce
Tanzania Journal of Science
This paper describes a case study in which a zero one mixed integer linear programming model was formulated and used to analyze marketing costs of coffee marketed by Kagera Co-operative Union. The solution of the model indicated a potential decrease of about 18% in the marketing costs. It is hoped that the model can be applied to other crops.
Optimum Design For Spring With Orthogonal Design Method, Han Fu - Jie
Optimum Design For Spring With Orthogonal Design Method, Han Fu - Jie
Tanzania Journal of Engineering and Technology (TJET)
Orthogonal design method is a sort of direct optimum method, by which the op- timal result may be obtained through simple computation and analysis. This method has gained increasingly extensive interest in scientific research, engineering design, end production management as well. The orthogonal table is the basic instrument for carrying out optimum design with orthogonal design method. It is a mathernatical table established On the basis Of the idea of isostatic distribution. As various levels may appear in any column, it makes a partial experiment contain levels of all factors furthermore. RII combina- tions of any two columns may appear …
Theoretical Analysis Of Thermodynamic Consistency Of A Reiner-Rivlin Fluid, V.G. , Masanja
Theoretical Analysis Of Thermodynamic Consistency Of A Reiner-Rivlin Fluid, V.G. , Masanja
Tanzania Journal of Science
The thermodynamically admissibility of a Reiner-Rivlin fluid undergoing a two dimensional axisymmetric flow process has been investigated analytically. The Clausius-Duhem inequality shows dependence of the viscosity coefficients on kinematical quantities, hence no general restrictions can be made on the non-Newtonian viscosity coefficient. However specific restrictions have been made by considering a cubic degree fluid. It is concluded that the rheological equation of state is an approximate model of the constitutive behavior of a real fluid and that the thermodynamic consistency of a flow process can basically be proved numerically.
Control System Design Program Based On Cascade Compensation, Fredrick Ishengoma
Control System Design Program Based On Cascade Compensation, Fredrick Ishengoma
Tanzania Journal of Engineering and Technology (TJET)
CAD is becoming more widely accepted in the design and analysis of control systems. A program has been developed for analyzing single-input single-output linear time-invariant control system. The application of the progranl for frequency domain design of cascaded phase lead and phase lag coinpensators is briefly discussed. Two examples to illustrate the program are presented.
Optimization Of Dispersed Flor Pond For Bacterial Removal, Mayo A. W
Optimization Of Dispersed Flor Pond For Bacterial Removal, Mayo A. W
Tanzania Journal of Engineering and Technology (TJET)
The design of waste stabilization ponds is seldom done with consideration of optimum pond dimensions. The analysis of pond dimensions within practical limits in dispersed flow ponds on the basis of minimum cost for the predetermined bacterial remova) ef ficiency, with the aid of computer is presented. The data collected in the pilot and full scale waste stabilization ponds at the University of Dar es Salaam Was used as input to the computer program. The results shows that pond configuration and climatic conditions which have influence on bacterial mortality rate have a re:narkable influence on pond cost
Hydrodynamic Stability Of The Breakwater Extension At Rrviksand, Norway, Alfonse Dubi
Hydrodynamic Stability Of The Breakwater Extension At Rrviksand, Norway, Alfonse Dubi
Tanzania Journal of Engineering and Technology (TJET)
The fishing port of Årviksand in Norway, which is situated on an open coast, is artificially harboured by breakwaters. The northern and southern breakwaters which were built in 1930—ies and 1950—ies respecti vely have been on several occasions damaged by heavy storms. This resul ted in the need for further protection by extending the northern breakwater. This paper describes one of the hydrodynamic tests on the breakwater extension. The breakwater, with a berm breakwater concept design, is subjected to the joint probability of sea level elevation and wave heights (in other 'fatigue" test). words , It is found that cover …
Evaluation Of Wind Data Records To Predict Extreme Extreme Wind Speeds In Tanzania, L Lwambuka
Evaluation Of Wind Data Records To Predict Extreme Extreme Wind Speeds In Tanzania, L Lwambuka
Tanzania Journal of Engineering and Technology (TJET)
The progress made towards evaluation of local wind data records to pred ict extreme values of wind speeds in Tanzania is being presented . Records of wind data, stored continuously since 18 years, have been compiled and statistically processed. Extreme value theory of Fisher —Tippet Type I has been fitted into the data to abstract extreme values of wind speeds for locations at which the wind data records were obtained. A reliable wind map of Tanzania containing basic wind speeds at 18 locations across the country has been produced. The basic wind speeds are being recommended for des ign against …
The Hydraulic Performance Of A Vortex Tube Foector, F Mtaro
The Hydraulic Performance Of A Vortex Tube Foector, F Mtaro
Tanzania Journal of Engineering and Technology (TJET)
The vorle.r tube silt exrrac/or consists of a pipe, rhe crest of which has a slit and lies flush across lhe canal bed.With minimal warer loss, I.oe bedload is extracted through lhe slil settling canal back ro the river, thus reducing or eliminating the bedload transported in main canal. Ihe resulting swirling flow phenomena is of complex nature and depends on sc conirol paramerers, as a result of which previous empirical design approaches have yielded conflicting guidelines. By means Of a simplified hydraulic system, the flow mechanism and energy in rhe can be determined.