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Nitrogen Oxides Rbsorption Into Sodium Hydroxide Solution In A Packed Column Column: Effect Of Naoh Concentration, J Katima

Tanzania Journal of Engineering and Technology (TJET)

Experiments have been conducted to evaluate the ettect of sodium hydroxide (NaOH) concentration upon the absorption rate of nitrogen oxides (NO ) and packed column performance. The absorption process using was carried out at atmospheric pressure and 29B K, concentrations between zero and w/ w, NO/ NO ratio of 0.5 and NO concentrations between 150 and 10000 ppm in an air mixture. The performance of the calumn was enhanced by the presence of hydroxyl ions ( 0B - ) relative to the absorption into water, however, The absorption it was found to be independent of NaOH concentration. rate of NO …

Carrying Capacity And Cracking Resistance At The Of Halving Joints In Reinforced Concrete Beams, S Mpinzire;

Tanzania Journal of Engineering and Technology (TJET)

Results are presented from tests on 3 beams having discont inuous support zones. All Of them had web and diagonal shear reinforcement. TWO out Of the three represented beams, their test results have been analysed in a paper designated part I which appeared in the Uhandisi Journal , Vol. I December 1989. They have been presented in this paper for compar ison purposes. The third beam has been made to invest i gate the effect of anchoring diagonal shear reinforcement by spot Welding method. The third beam was tested With two concentrated loads in the span. In all beams several …

A Finite Element Analysis Of Wood In Transverse Compression, A Mrema

Tanzania Journal of Engineering and Technology (TJET)

A two dimensional finite element analysis is utilized to predict the stress and strain distributions for wood in transverse compression. Important key var iables are incorporated into the ana lysis to define their influence on the stress and strain distributions. These variables are geometry of loading, geometry of specimen and the orthotropic ratio of the material. Based on the finite element analysis results, relationships are arising stress from developed relat ing maximum stress concentrations to the above three variables. possible appl ications of the results from this study relate to the development of more efficient design of connections such as …

Comparative Study Of Inlet Manifold Tuning To Enhance Supercharge, Mtui L

Tanzania Journal of Engineering and Technology (TJET)

Computer model ing and experimental results on a single cylinder, four-stroke cycle engine for best air flow characteristic is The modeling analysis is based on hornet ropie fluid di scussed . The model n g resul s is flow w it. h constant: specific heats. included to val idat.e the s imulation program against experimental results with widely vary ing manifold lengths and engine speeds. ExperimenLal results are obtained by measuring air f low rates Lo the inlet valve during steady g Late speed Of Lhe engine. Manifold tuned lengths are Obtained for a range Of speeds by exper and …

Effects Of Feed Solids Concentration On Dual Functionality Of A Hydrocyclone., Zanzu M

Tanzania Journal of Engineering and Technology (TJET)

The dual functionality, i.e. thickening and classification of a 50.8mm diameter hydrocyclone has been investigated. A metallurgical slime consisting of a 50% mixture of quartz and petroleum coke was used in the tests. It was found that in order to achieve both thickening and classification at the same time, the pressure drop across the hydrocyclone, the underflow diameter and the feed solids content have to be subtly controlled.

Transport Matrices Of Finite Beams Resting On Elastic Foundations, M. W. Giger

Tanzania Journal of Engineering and Technology (TJET)

A method of derivation of the coefficients of the transport matrix for a finite element resting on one and two-parameter elastic foundation soils is outlined. The coefficients are summarized for both the Bernoulli–Euler and the Timoshenko beam model in tabular form, for general reference. In addition, bounds on the parameters describing beam/soil flexure, beam and soil shear, which govern the validity of the two-parameter elastic solutions are provided in graphical form.

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 …

A Study Of Load Bearing Capacity Of Piles Driven In The Zanzibar Harbour Submarine Soils, A. M. Dubi

Tanzania Journal of Engineering and Technology (TJET)

The rehabilitation of the Zanzibar Port involved, among other things, driving piles into the submarine soils. Pile driving fractures the coral and as a result creates a gap filled with loose fractured coral between the unfractured coral and the pile. Grouting of the external surface of the pile is done to strengthen the fractured coral. In this paper, two grouted working piles (TP6 & TP61), randomly chosen from the pile group, were load tested to twice the design load. The test results indicate adequacy of the bearing capacity of the grouted piles.

Force Displacement Relationship For The Prediction Of Structural Fluttering, Ladislaus Lwambuka

Tanzania Journal of Engineering and Technology (TJET)

A new presentation of force displacement relationship for the prediction of structural fluttering is discussed in this paper. This topic is limited to a detailed discussion of the derivation of the equations of motion for the rigid streamlined airfoil/flat plate system of three degrees of freedom, which yields expressions for aerodynamic resultant forces due to a steady air flow. The equations of motion presented herein are derived from the conventional classical complex presentation transformed into real matrix equations. This new presentation of the equations of motion constitutes the foundation for the latest state-of-the-art of predicting critical wind loads on the …

Numerical Investigation Of A Non-Newtonian Material Through A Sudden Pipe Expansion, V. G. Masanja

Tanzania Journal of Engineering and Technology (TJET)

A numerical method for solving two dimensional elliptic boundary-value problems of fourth order is used for finding stationary solutions of the equations of motion for a laminar flow through a sudden pipe expansion of an incompressible non-Newtonian fluid with a constitutive equation of the Reiner-Rivlin (R-R) type. Results for the Newtonian fluid, which is a special case, are in excellent agreement with those by previous investigators and they demonstrate the reliability, superiority and accuracy of the method. Results for the non-Newtonian cases could be of value for fixing ideas about visco-elastic behaviour although the R-R fluid allows only inelasticity: this …

Carrying Capacity And Cracking Resistance At The Support Zone Of Halving Joints In Reinforced Concrete Beams, H. W. Chung

Tanzania Journal of Engineering and Technology (TJET)

Abstract

Simulation Of Fluid Flow In Packed Beds Using A Simplified Model And Network Analysis Technique, Haggai W.K. Sarakikya

Tanzania Journal of Engineering and Technology (TJET)

Abstract

Metabolic Activity Of Microorganisms Cultured On Inhibitory In Unsteady State, Cleophas L.C. Migiro

Tanzania Journal of Engineering and Technology (TJET)

Abstract

Flowsheet Simulation Studies Of New Oilseed Extraction Processes, M. Khalfani

Tanzania Journal of Engineering and Technology (TJET)

Results are reported on the flowsheet simulation studies of new oilseed processes suitable for local conditions. A process model was developed and new design simulation methods using Computer Aided Design (CAD) approach were employed for the preliminary investigation of a number of alternative scenarios.

Results have shown that new processes should give considerable investment savings if separation of the crude product is not carried out by distillation. However, the economics of processes using alternative separation technology is highly dependent on operating conditions.

The use of spreadsheet programs for flowsheet evaluation studies offers opportunities for application of CAD techniques in local …

A Reiner-Rivlin Fluid Flow Through Entrance Region Of A Circular Pipe, V. G. Masanja

Tanzania Journal of Engineering and Technology (TJET)

The flow of a Reiner-Rivlin fluid with two viscosity coefficients through the entrance region of a circular pipe has been studied numerically. In particular the growth of the entrance length as a function of the Reynolds number and the non-Newtonian parameters has been examined. Where comparison could be made, the results have been compared with existing experimental -and numerical data as well as the limited theoretical work available.

Carrying Capacity And Cracking Resistance Of The Bracket, S. Mpinzire

Tanzania Journal of Engineering and Technology (TJET)

Abstract

Behavior Of Ductile Materials Under Impulsive Loading, M. Y. Brunner

Tanzania Journal of Engineering and Technology (TJET)

Ductile materials under dynamic loading are known to be able to absorb energy and thereby delay or even prevent structural failure. This paper is concerned with such behaviour in the case of impulsive loads of short duration. It is shown that even when the feared, unstable, labile condition is attained, failure may not necessarily occur. This behaviour is particularly impressive for structures with large mass, because it is essentially the mass which slows down the attainment of the failure strains. If the impulsive load dies away quickly enough, the constant plastic resistance will be adequate to bring the increasing deformations …

Winery Waste Utilization-A Case Study Of Dowico, J. H.Y. Katima

Tanzania Journal of Engineering and Technology (TJET)

The Dodoma Winery Company (DOWICO), is presently processing about 1000 tonnes of grapes to produce different types of wines, with left overs of about 200 as wastes. These wastes are dumped outside the factory, obviously, a poor method of waste disposition as far as the environmental significance is concerned. Since the expansion programme, to enable the plant to handle up to 30000 tonnes of grapes per year is in the pipeline the best method of disposing the huge amount of waste (about 6000 tonnes) that will result, has to be sought.

This paper highlights the financial and sanitary advantage of …

Computation Of Frequency Characteristics Of Lumped-Element 3 Db Branch Line Directional Couplers, H. R. Mgombelo

Tanzania Journal of Engineering and Technology (TJET)

An analysis of the 3 dB lumped-element branchline directional coupler constructed using L-C and T networks is given. Matrices of lumped element capacitances and inductances in the form of low and high pass filters are equated to the matrices of the distributed element transmission lines at the centre frequency of operation, as a result of which design equations are derived. Using even and odd modes of excitation, frequency characteristics of the directional couplers are computed and compared to those of the coupler constructed using distributed element transmission lines.

Relationship Between Magnetic Ageing, Metallographic Evidence Of Ageing And Composition For Cold Rolled Si-Fe Electrical Sheets, J .V .Tesha

Tanzania Journal of Engineering and Technology (TJET)

The cold rolled Si-Fe sheets used for the production of the current cores for electricity meters suffer from ageing which causes an irreversible change in the magnetic properties. The ageing process is due to the precipitation of mixed iron silicon carbides in the microstructure. There exists already a thermal treatment and magnetic properties measurements method to detect the susceptibility to ageing. This requires a minimum of 1000 hours. In order to find the correlation between magnetic ageing, composition and metallographical evidence of ageing, different Si-Fe sheet compositions were investigated using the optical microscope to observe the time to appearance of …

Application Of Mechanical Vapour Recompression To Industrial Slides Drying, Allan Issangya

Tanzania Journal of Engineering and Technology (TJET)

A positive result of the oil crisis of the seventies is the realisation of energy’s value and the need to use it sparingly. Increasing attention has been focussed on all aspects of industry where fuel oil and gas had played a major role.

Industrial drying, one of the most widely applied unit operations in chemical and process engineering, is a highly energy intensive operation. Studies have identified a number of alternatives for lowering energy consumption in this process through various heat recovery techniques.

Due to the difference in their operating principles steam-heated dryers and air-heated dryers, in most aspects, require …

Optimal Allocation Of Water Among Industries In Dar Es Salaam City, Tanzania, J. I. Matondo

Tanzania Journal of Engineering and Technology (TJET)

Dar es Salaam is the city with the largest number of industries in Tanzania. However, the water demand for these industries is more than the supply. Therefore, there is a water use competing problem among the industries. Dynamic programming technique has been applied to optimally allocate the available water among the industries with the objective of maximizing the net benefits. Results reveal that, industries with the highest net return per unit of water will get the first priority of being allocated water.

Computer Model For Baker’S Yeast Production, A. K. Temu

Tanzania Journal of Engineering and Technology (TJET)

This paper concerns modelling of fermentation for bakers’ yeast (Saccharomyces Cerevisiae) production using sugar cane blackstrap molasses as a feed. The problem constitutes of expressing physical phenomena, mathematically, as function of operating conditions.

The program developed is easy to run and does not cost much in terms of preparations. With this program different operating conditions were tested and results show that available equations are not exhaustive. Thus more research is recommended.

Effect Of The Variations Of The Mobile Dislocation Density On The Thermally Activated Cyclic Deformation Behavior, J. S. Mshana

Tanzania Journal of Engineering and Technology (TJET)

The application of the transition state theory of rate processes to describe tension-tension, strain controlled cyclic deformation BEHAVIOUR was extended to describe the effect of the variations of the mobile dislocation density on the cyclic deformation BEHAVIOUR. It was shown from the derived constitutive relation that due to the net increase in the mobile dislocation density during strain controlled cyclic deformation the stress change per cycle (or in function of time) increases.

Development Of A Spray Drought Cooling Tower, O. K. Kaunde

Tanzania Journal of Engineering and Technology (TJET)

ABSTRACT A noval type direct contact cooling tower has been proposed in which the gas or air entering the tower is drawn by the ejector action of the sprays through which the feed water is admitted. The advantage offered by this type of tower is that it eliminates the usages of fan, thus saving the capital cost and power to drive it.

Entrainment of air by water was studied in a laboratory cooling tower and the result of the entire experiment indicate that the development of a spray drought tower is a feasible practice.

Production Of Blanking Circles And Dies - An Appropriate Method, V Bhandari

Tanzania Journal of Engineering and Technology (TJET)

A large important blanking die for production of multiwick stoves oil tanks was damaged beyond repair during normal maintenance. A replacement die could not be made available immediately. Initially an alternative blank production system based upon the adaptation of the inhouse and locally available tools was set up. Subsequently a temporary low cost and a permanent replacement blanking die was designed, developed and manufactured out of pad welding of mild steel plate. Recommendations have been drawn in light of the experiences gained in the deployment of these appropriate methods.

Towards The Development Of A Seed Minimum Tillage Planting, G Mutoizi

Tanzania Journal of Engineering and Technology (TJET)

Some advantages of minimum tillage compared to conventional tillage. systems are given. An evaluation of current minimum tillage planters is then made identifying two major problems namely the handling of trash. which detracts from making a continuous furrow of uniform depth, and unnecessary power Consumption When making this continuous furrow in spaced planting of seeds. Then the design, manufacture and development of a rig type of a seed injector for use in precision-drilling of a typical tropical geed is presented. It is to inject the Seed using rotary sleeve Valve in which is tractor drawn. Preliminary field testing of the …

The Design Of A Resonant Post Waveguide Filter, Ramjee Prasad

Tanzania Journal of Engineering and Technology (TJET)

A seven stage, quarter-wave coupled, single post, resonant cavity type waveguide filter has been studied. The posts are placed according to the Tchebyscheff distribution. The filter is designed and fabricated to meet the following specifications: Centre frequency: 9.31 GHz, Number of stages = 7, 3-dB bandwidth = 300 Mhz, Ripple tolerance in the passband = 0.5 dB. The frequency behaviour of this filter has been experimentally studied and is in close agreement with the specifications.

Distributive Mixing Performance Of Rubber Internal Mixers, B Mutagahywa

Tanzania Journal of Engineering and Technology (TJET)

Results of experiments to study the distributive mixing performance of Internal mixers are reported in this paper. Distributive mixing was assessed by monitoring the uniformity of sulphur distribution throughout rubber mixes subjected to a range of rotor revolutions. The results indicate that distributive mixing in a well controlled Internal mixer is rapid and unlikely to be a source of mix variability.

Gain Margin And Phase Margin Interrelationships, M Luhanga

Tanzania Journal of Engineering and Technology (TJET)

The gain margin and the phase margin Of a control SY Stem are important parameters in the determination of the relative stability of control system. In this paper We derive general interrelationships between these parameters.