Operations Research, Systems Engineering and Industrial Engineering Commons^™

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

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

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

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 …

Comparative Study Of The Dynamics Of Circulating Fluidized Bed Riser And Downer Of Equal Diameters, Samwel V. Manyele

Tanzania Journal of Engineering and Technology (TJET)

The microscopic flow dynamics of the 100-mm internal diameter riser/downer circulating fluidized bed (CFB) unit were monitored using a solids concentration fiber optic probe. The comparison was conducted by comparing radial profiles Of the dynamic parameters derived from time-series analysis techniques (statistical and chaos analyses). The solids concentration signals used were recorded under similar operating conditions (gas velocity of 8.0 m/s and solids flux of 100 kg/m2s). Similar axial elevations were compared (entrance and fully developed sections of die reactors). A1 each loca!ion, the signals were sampled a! afrequency of 970 Hz for duration of 30 seconds. It was observed …

Aeration Efficiency Of A Three-Phase Fluidized Bed Bioreactor During Food Industry Wastewater Treatment, S Manyele

Tanzania Journal of Engineering and Technology (TJET)

The implementation Of a three-phase fluidized bed bioreaclor (TPFBB) in food- processing wastewater (FPW'W) treatment is reported. This study includes the modification Of the air distributor (plate design and gas-liquid mixing) for the bioreactor and resting of its aeration efficiency under different liquids. The aeration efficiency for wastewater samples collected from a soft drink processing industry and tannin processing industry (TANWA T) and tap water were compared. The aeration efficiency parameters studied include bed expansion, air holdup. volumetric oxygen mass transfer coefficient, and alpha factors. The variation of these parameters With air flow rates were studied at different liquid heights, …

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 …

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.

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

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

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. …

An Integrated Model For Technology Assessment And Choice For Rural Development In Developing Countries, Abdallah Chungu

Tanzania Journal of Engineering and Technology (TJET)

Abstract

Load Flow Solution For Three-Phase Mv Radial Distribution Connected Network Supplying Different Line Topologies, B. J. Kundy

Tanzania Journal of Engineering and Technology (TJET)

In this paper, a load flow solution for the Medium Voltage (MV) three-phase radial distribution in delta-delta (Δ–Δ) connected network supplying different line topologies such as three phase, phase to phase and single-wire earth return (SWER) networks is presented. The general voltage related network equations are developed using Kirchhoff’s voltage and current laws. Development of a solution to the load flow analysis applying the developed general voltage related network equations is proposed in order to evaluate the network voltage profile. Various numbers of arrays are developed for the identification of the network under study. The proposed method is a new …

A System Thinking Approaching Maintenance, Production And Quality, E. A. M. Mjema

Tanzania Journal of Engineering and Technology (TJET)

The concepts of system thinking and its applicability in maintenance management was analysed in this article. The author analysed various maintenance policies, which have inclination to the concept of system thinking. The maintenance policies revisited include the Integration of Maintenance (IM), Total Quality Maintenance (TQMain), Failure Mode and Effect Analysis (FMEA), and Total Productive Maintenance (TPM). All these strategies are aimed at utilising effectively the maintenance personnel by giving some of the responsibilities of maintenance to production personnel. It was found that, although the founder of these techniques did not mention the concepts of system thinking in their methods, however, …

Incorporating E-Commerce Technologies Into Small And Medium Manufacturing Industries In Tanzania, M. A.M. Victor

Tanzania Journal of Engineering and Technology (TJET)

Businesses worldwide are making use of the new opportunities which have been brought up by the developments in Information and Communication Technologies (ICTs), particularly the Internet. Big businesses, especially those multinationals in the developed nations have invested heavily on these technologies and they are reaping their benefits. This paper reports on a study conducted to look at the key issues to be considered in order for small and medium enterprises (SMEs) in Tanzania be able to position themselves technologically in what is termed as E-commerce. Cost and benefits, policy, training and infrastructure issues are looked at in this study.

Comparison Of Repair Costs Of Two Wheel Drive Tractors Under Tanzania Conditions, S. M. Mpanduji

Tanzania Journal of Engineering and Technology (TJET)

The repair costs of 2WD tractors were investigated in order to provide important information, which lacks in the scope of agricultural mechanization in Tanzania. Previously repair cost functions established for tractors in developed countries were used for both theoretical and practical purposes. The findings of this study have revealed that repair costs of tractors vary substantially from one make to another. The prediction functions developed in this study indicated that the magnitudes of repair costs in Tanzania are higher than the repair costs established in Europe and North America. The reason for this could be either due to high cost …

Production Of Biogas From Water Hyacinth: Effect Of Substrate Loading In Semi-Batch & Batch Operations, J Katima

Tanzania Journal of Engineering and Technology (TJET)

A study was carried out to establish the effect of substrate loading rate on the production of biogas from water hyacinth. The experiments revealed that the maximum methane yield in a batch process was 0.166 normal litre (NLVg Of volatile solids (VS) added at substrate concentration of 25 g dry mass'litre after five days of incubation. The maximum methane yield in a semi-batch process was 0.153 NWg VS added at 1.30 g VS'litre day and retention time Of 15 days.

Recyclability Of Modified Ps-Aq Pulps At Around Kappa 30, Rwaichi Minja

Tanzania Journal of Engineering and Technology (TJET)

Bleachable grade pulps prepared from Nonvegian softwood spruce chips while simulating possible alternatives of improving pulp yield by application Of polysulphide (PS) and anthraquinone (AQ) have been used in this study. The tests for recyclability were performed on hydrogen form pulps. The pulps considered were Iso- Thermal cooking (ITC) kraft pulp which was used as a reference pulp, conventional PS-AQ pulp, soda PS-AQ pulp and kraft PS-AQ pulp. The loss Of swelling ability (homification) Of the pulps, was determined by measurement of water retention value (W R V). The results showed that, PS-AQ pulps had similar or slightly better swelling …

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 …

Strategic Transformation Of Public Enterprises In Tanzania: Action Research Oriented Methodology, M A.M Victor

Tanzania Journal of Engineering and Technology (TJET)

Naturally, enterprises are dynamic in the sense that they can either grow or shrink. Growth is the wish of all owners and particularly of fast growth. We talk of growth here as both increasing the speed of circulation of the working capital profitably and increasing the size or expansion of the fixed assets through retained earnings. Proper management will in most cases assure a gradual growth. However, in some situations, gradual growth may not be sustainable due to global competition and/or some other political changes such as elimination of monopoly. In these situations, enterprises will need a strategic transformation, not …

Production Innovation Through Design Methodology: Development Of A Fuel Pump For Motorists, E. Elias

Tanzania Journal of Engineering and Technology (TJET)

Design Methodology is a discipline of scientific engineering design for provision of solutions to user needs. It is composed of design models (showing the path/procedural steps of design) and design tactics (i.e. techniques, technologies and methods aiding the designer). When rigorously applied, design methodology leads to innovation of products and businesses.

The present paper describes how design methodology was applied to the development of a siphon device (Apump@) for motorists when in need to refill fuel in their vehicles away from petrol stations. The need for the device was realised through the method of Alooking around & deep thinking@ and …

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 …

New Technologies For Thermal Disposal Of Sewage Sludge, T Ogada

Tanzania Journal of Engineering and Technology (TJET)

The traditional methods for the disposal of sewage sludge are landfilling, recycling as fertilisers in agricultural lands, dumping into sea and incineration. In thc recent past, Sludge incineration has been rapidly gaining ground duc to environmental constraints facing the Other methods. However, the cost of pollution control during sewage sludge incineration is currently very high due to the expensive flue gas treatment facility required. Futhermore, large quantity Of ash is produced which is highly contaminated with heavy metals and must be disposed off in special landfilling sites in order to avoid ground water pollution. To reduce the cost Of pollution …

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 …

Experimental Study Of Domestic Charcoal Stoves, Simbo Kimario

Tanzania Journal of Engineering and Technology (TJET)

The demand of fuelwood for domestic cooking especially the charcoal fuel is increasing in the urban settlements due to the increase in population of low income class earners who are the main consumers Of this type of fuel. This paper is presenting rhe results Of experiments conducted on the popularly used domestic charcoal stoves in Tanzania. The results revealed some significant differences on stoves performances. The type of insulation materials and some design features incorporated into the combustion chambers of the stoves had positive impacts in relative charcoal fuel saving. About two tons of charcoal fuel could be saved by …

Oxygen Transfer In A Three-Phase Fluidised Bed Bioreactor With Novel Biomass Support When Used In Industrial Wastewater Treatment, S Manyele,

Tanzania Journal of Engineering and Technology (TJET)

The effect of support mass and liquid height on the oxygen transfer in the three- phase fluidised bed were experi/nenta/ly investigated. Novel biomass support, rhe KMT*, with density of 850 kg/n/ and an equivalent size, dp 8.3 mm, has been used in this work. The oxygen transfer rate was expressed in terms of rhe volumetric oxygen transfer coefficient, kca. It has been found out that the* a values increased with increasing support mass up to a critical solids load of 4.0 kg, above which the kca decreased and that kca decreased with increasing liquid height. It has been recommended that …

Technical And Economic Comparison Of Performance Between Farmer And Government Managed Irrigation Schemes In Tanzania: A Case Study Of Kapunga Irrigation Project, D Chemka

Tanzania Journal of Engineering and Technology (TJET)

This paper conwares the perforinance Of governnyent ro fanner-managed irrigation schemes at Kapunga Rice Project in Mbeya Region, south-west Tanzania. The results showed that the farmer-managed irrigation scheme (FMIS) performed better than the government-managed irrigation scheme (GMIS) in attaining good performance. Applicable indicators for farmer-managed irrigation scheme are as shown below with those of government-managed scheme indicated in brackets. Its overall irrigation efficiency was 61' percent (29 percent) average productivity was 3.2 ton/liG (2.2 ton/ha); economic profirability: internal rate of return was 3.2 percent (5 percent), benefit/cost ratio of 0.60 (0.14); while its financial profitability: internal rate of return was …

The Significance And Effects Of Oil Injection On The Performance Of Sliding Vane Compressors., M Mkumbwa

Tanzania Journal of Engineering and Technology (TJET)

A computer model of a sliding vane air compressor was used to predict the behaviour of machines having different geometries operating at different conditions. The performance parameters which were calculated by the model were the free air delivery, power input and specific capacity which is defined as the free air delivery per unit of power input.The model also included the study of the effects of Oil injection on these mentioned compressor performance parameters. The paper describes the simulation model developed incorporating an analysis Of the effects of the oil injected into the compressor on lhe thermodynamic processes taking place in …

A Study On Ring Pack Lubrication In Internal Combustion Engine, I Mshoro

Tanzania Journal of Engineering and Technology (TJET)

Most efthe lubricating oil from Internal Combustion Engine (ICE) is lost through piston rings. Hence, in order to optimally reduce ICE oil consumption, a better insight into tribology of the ring pack is required. This can only be achieved by an inwroved characterization of the lubricant behaviour within the opelating environment of the engine. In The present ieork, an optical tcchnique using laser- induced fluorescence was employed to measure oil film thickness within the ring pack. The experiment was conducted on a Phaser 1000 Series engine, whereby optical access to the ring pack was achieved by a fused silica-window positioned …

Sustaina Bility Of Irrigation Schemes For Small-Scale Farmers: A Case Study Of Irrigation Scheme At Buleya Malima, Gwembe Valley, Zambia, Masinja R

Tanzania Journal of Engineering and Technology (TJET)

A study to determine facrors influencing sustainability of smallholder irrigation schemes was carried our a! Buleya Malima, Southern Province, 7_nnzbia. These factors included technical and socio-economic factors. found Out that the technical factors were 26.5, 64.5 and 9.2 percent for application efficiency, tailwater ratio and deep percolation, respectively, indicating that farmers wasted water mainly through tailwater runoff.From socio-economic point of view, the study indicated that the scheme lacked (i) farmer participation in designing and planning operation of the scheme (ii) managerial ability and innovativeness to form their own viable organisation: and (iii) formal training in technical operations of irrigation, infrastructure …