Digital Commons Network^™

Defects In Reinforced Concrete Due To Environmental Conditions And Concrete Treatment: A Case Study At The University Of Dar Es Salaam, A. Rubaratuka

Tanzania Journal of Engineering and Technology (TJET)

Concrete is produced by mixing together cement, water and aggregates (i. e. sand and coarse aggregates) in specified proportions. It can do well with compressive forces but it is very weak under tensile forces. To overcome this problem, steel reinforcement are normally added to produce reinforced concrete which can also withstand tensile forces. Experience shows that environmental conditions may have a negative impact on the durability of reinforced concrete structures resulting in development of defects if not properly assessed and appropriate measures adopted to arrest the same at the design and construction stages.

The severity of damages for the investigated …

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 …

The Behaviour Of Reinforced Block-Work Walls In Axial Tension, Laurent Shirima

Tanzania Journal of Engineering and Technology (TJET)

Reinforced blockwork with horizontally laid reinforcing bars is used for walls in liquid retaining structures in developing countries. This is the case where, the level of technology in terms of skills and equipment is not in a position to allow successful construction of reinforced concrete walls. Blockwork walls are very sensitive to cracking which cannot be prevented by reinforcement. The major problem for designers is the behaviour of such walls in tension caused by hydrostatic pressure of the stored liquid. This paper reports results of a research work to study the behaviour of reinforced blockwork walls in tension. It was …

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 …

Measurement Of Markstein Lengths In Laminar Spherical Explosion Flames, E .M.J Mushi

Tanzania Journal of Engineering and Technology (TJET)

Schlieren photography was used to record the development of spherical flames in a combustion bomb. Flame speed and flame stretch were evaluated from the data and used to evaluate Markstein lengths and numbers. The results indicate a strong influence of both the spark discharge energy and equivalence ratio. Low spark discharge energy is observed to give rise to more unstable flames compared to high energy sparks. It is observed that for the range of energy tested, 80 and 400 mJ gave the best stability for the flames. For equivalence ratio less or equal to 1.225 an 80 mJ discharge results …

Evaluation Of Extreme Wind Speeds In Relation To The Design Of Coastal Structures In Tanzania, Alfonse Dubi

Tanzania Journal of Engineering and Technology (TJET)

Five distribution functions, FT-I and Weibull with the exponent k = 0.75, 1.0, 1.4 and 2.0 respectively, have been applied to 25-year wind data collected between 1972 and 1996 at Tanga, Dar Es Salaam, Zanzibar and Mtwara Meteorological stations. One maximum value for every year from the full data record was drawn to constitute the annual maxima series for each station. For each of the stations, 2-, 50- and 100-year return wind speeds with corresponding 90% confidence intervals were computed. The distribution functions were fitted to the data by the Least Squares Method. Results from the study show that FT-I …

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 …

An Investigation Into The System Of Managing Maritime Safety And Environment Protection In The United Republic Of Tanzania, Musa H. Mandia

World Maritime University Dissertations

No abstract provided.

Grain And Fertilizer Handling Gbhl Terminal : An Analysis Of Its Impact On Port Fraternity And Its Post Effects On Bulk Traffic Through The Port Of Mombasa, Evelyn Umazi Mwamure

World Maritime University Dissertations

No abstract provided.

Analysis Of Kenya's Transport System As Service Provider And Gateway To The Northern Corridor, Beatrice Nyamoita

World Maritime University Dissertations

No abstract provided.

Investigation On The Possible Causes Of Declining Dry Cargo Throughput At Dar-Es-Salam Port, Nelly Kyejo Mtaki

World Maritime University Dissertations

No abstract provided.

A Model Met Institute For The East African Region : Creating An Effective Infrastructure For Outreach And Improved Standards, Musa Hassan Musa

World Maritime University Dissertations

No abstract provided.

The Effect Of System And Oxygen Partial Pressure On Single Coal Particle Heterogeneous Ignition Temperature Under Conditions Of Negligible Convection; Experimental Observation, H. Katalambula

Tanzania Journal of Engineering and Technology (TJET)

Abstract Under conditions of high volatile concentrations, the influence of oxygen concentration on single coal particle ignition becomes more significant. The high volatile concentration conditions have been simulated by employing a microgravity environment. Results show that under these conditions, the heterogeneous ignition temperature decreases faster with increasing oxygen concentration than under normal conditions. The ignition temperature also decreases with increasing system and oxygen partial pressure under both conditions. Generally, the system and oxygen partial pressure show similar and complimenting effects on ignition temperature.

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.

Evaluation Of Soil Conservation Measures: A Case Study In Mbinga District, Ruvuma Region, Tanzania, S. Y. Thadei

Tanzania Journal of Engineering and Technology (TJET)

A study on soil conservation measures was conducted in two villages, Tukuzi and Mahenge, in Mbinga District, Ruvuma Region, Tanzania. The results showed that the ngoro farming system was effective in controlling soil erosion by water on both steep and gentle slopes. Sediments collected from ngoro had high concentrations of plant nutrients such as available phosphorus (P), total nitrogen (N), organic carbon (OC) and exchangeable bases. This was probably due to nutrients released from decomposed grass bundles buried in the soil. In preventing soil erosion, ngoro and bench terraces were equally effective, while contour ditches were as effective as ridges …

Production Of Fermentable Sugars From Waterhyacinth By High-Temperature Dilute-Acid Hydrolysis Method, J. H. Y. Katima

Tanzania Journal of Engineering and Technology (TJET)

A study on acid-catalyzed hydrolysis of Waterhyacinth (WH) biomass for production of monomeric sugars has been done. Waterhyacinth (Eichhornia Crassipes) plants were obtained from Lake Victoria. A yield of 18.5% w/w fermentable sugars was achieved during hydrolysis of oven-dried Waterhyacinth (ODWH) biomass at 220°C and 1.5% w/w H₂SO₄ acid. The waterhyacinth (WH) hydrolysates obtained from a high-temperature dilute-acid hydrolysis were rich in six-carbon (C₆) sugars (glucose) which could be fermented to ethanol. The production of fermentable sugars from waterhyacinth biomass is a promising new opportunity for its economic value which can in turn accelerate its rate of harvest and utilization.

Estimation Of Volatile Cloud Density For Single Coal Particles Using Microgravity Condition, H. Katalambula

Tanzania Journal of Engineering and Technology (TJET)

Single coal particle’s volatile cloud density has been estimated by employing a microgravity condition. The volatile yield was found to decrease with pressure while the density was found to increase, indicating that volatiles occupies less space when under pressure and hence causing some volatiles to be retained within the particle. The volatile cloud density was also found to increase with volatile yield suggesting volatile composition changes with yield. The effect of heating rate on volatile yield was found to be the same as reported by other investigators where the yield increased with heating rate.

Concrete Cracking In Coastal Areas, S. R. Mpinzire

Tanzania Journal of Engineering and Technology (TJET)

The paper discusses cracking and corrosion of reinforced concrete (RC) structures in coastal zones where aggressive action of salt burdened air is the primary cause of concrete deterioration. Case studies are presented, along with discussion of possible remedies including local demolition, reconstruction and epoxy injection as well as concrete treatment.

The Development Of Groundwater For Water Supply, C. F. Mhilu

Tanzania Journal of Engineering and Technology (TJET)

ABSTRACT This paper presents results of groundwater investigations carried out at Yombo Dovya Village, Temeke District in Dar es Salaam Region. The study has included hydrogeological and geoelectric resistivity sounding survey data obtained at the test site in Yombo village. The results of this investigation based on the application of vertical electrical sounding probe predictions have indicated the existence of reasonable amounts of groundwater resource for development. To verify these results borehole drilling tests were also conducted at the same site (Borehole No. DSM 79/99), and the results obtained by this method compares very well with those obtained earlier by …

Macrominerals In The Milk Of Healthy And Mastitic Cows, I E. Mohamed, O A. Olowni, F I. Habbani, G E. Mohamed

Tanzania Journal of Science

Concentration values were obtained using X-ray fluorescence (XRF) technique for chlorine, potassium and calcium levels in milk-from subclinical and clinical mastitis-infected COWS. Concentration values for sodium were determined using atomic absorption spectroscopy. Comparisons were made with healthy cow's milk. Subclinical mastitic milk had significantly higher levels of sodium and chlorine and significantly lower levels of potassium and calcium than the milk from healthy cows. Comparison between clinical mastitic milk revealed a significant increase in sodium and chlorine levels for clinical mastitic milk, while levels of potassium showed a non-significant change and calcium levels decreased significantly.

Tidally Induced Flow In Chwaka Bay Zanzibar, O U. Mwaipopo

Tanzania Journal of Science

Time series data of currents and sea current levels recorded by current meter and tide gauges, respectively from Chwaka Bay, Zanzibar were obtained from the entrance near to Mapopwe Creek and at the middle of the bay. The analysis of the data reveals that the tidal currents had an asymmetry near the entrance to Mapopwe Creek where the ebb currents were stronger than flood currents although the ebb periods were considerably longer than flood periods.

Stable Isotope Compositions Of Sedimentary Organic Matter Off Zanzibar Town, Ann Muzuka

Tanzania Journal of Science

Stable isotope compositions of sedimentary organic carbon for sediments collected off the Zanzibar Town averaged -17.9%. Low isotope values of organic carbon, which were associated with high C/N ratios, were observed within Zanzibar harbour suggesting a significant contribution of terrestrial organic matter to the harbour. Sediments collected outside the Zanzibar harbour were richer in ¹³C than those collected within the harbour area. This 13 enrichment in ¹³C can be attributed to a decrease in the influence of terrestrial organic matter (0M) and high contribution of' sea grasses. A decrease in the influence of terrestrial OM is further supported …

A Simple Method For Indexing Powder Diffraction Patterns Of Cubic Materials (11): Using The D-Values Of Reference, Me Kamwaya

Tanzania Journal of Science

From the d-values (in decreasing order) taken from powder diffraction patterns of the cubic material a variable constant, KQ, which is a multiple of Ʃh₁² where Q = l/d² can be determined. The smallest values of Q give rise to multiples of ones, twos and threes, which correspond to the smallest values of Ʃh₁² for the primitive, bcc, and fcc/diamond Type structures, respectively. Cognance of the lattice types is best accomplished by the ΔQ-criterion, where ΔQ denotes the difference between successive values of Q. Indexing is greatly simplified and the use of rigorous tables is …

Bis(4-Carboxylato-5-Methyl-Oxazolidine) Nickel(Ii)Dihydrate, Its Preparation And Crystal Structure, Me Kamwaya

Tanzania Journal of Science

An aqueous solution of nickel (Il) acetate tetrahydrate was added to warm solution of L-threonine and sodium bicarbonate. The mixture was subsequently treated with aqueous solution of formaldehyde and stirred until the blue solution turned green. The reaction consists in a base catalysed condensation of formaldehyde with L-threonine-nickel (Il) – complex followed by formation of an oxazolidine ring. A single crystal X-ray investigation was carried out at 120(1) ^oC. The X-ray structure analysis showed an octahedral nickel comp/ex containing two water molecules. The oxazolidine rings were connected to the Ni by nitrogen and one of the carboxylato oxygen atoms. …

Heavy Metal Content In Water Hyacinth (Eichhornia Crassipes (Mart) Solms.) From Lake Victoria Shore, Tanzania, Nk Mohammed, In Makundi

Tanzania Journal of Science

Water hyacinth (Eichhornia crassipes (Mart) Solms,) samples from Lake Victoria shore were analysed for heavy metal pollution using Energy Dispersive X-ray Fluorescence Spectroscopy (EDXRF). The roots of the water hyacinth samples were collected from areas influenced by industrial and domestic sewage and little influenced area. Water hyacinth from industrial area and those from sewage discharge points had higher concentrations of heavy metals than that from the little disturbed area.

Comparison Of Synchronization Strategies For Systems Employing Multiple-Code Markers, Hn Kundaeli

Tanzania Journal of Science

Frame synchronization strategies based on single-code markers have been widely researched and reported. On the other hand, frame synchronization strategies based on multiple-code markers have not been so well reported although they have become quite popular in systems operating at high transmission rates. In this paper, the performance of various synchronization strategies for systems employing multiple-code markers is compared. It is shown that, systems employing contiguous multiple-code markers have better performance than those employing distributed multiple-code markers. It is also shown that, systems in which the individual codewords of the markers are checked during loss of synchronization hare better performance …

Facies Analysis Of Limestones At Songo Songo Island In South East Tanzania, S Kapilima, Ka Msindai

Tanzania Journal of Science

Songo Songo Island is situated at close proximity of the continental slope of the coastal sedimentary basin of Tanzania. Its rich varieties of marine organisms and carbonate sediments provide a classic example of island emergence with the development of successive detrital and organic reefs as well as lime sand. Facies analysis at the Island was done through mapping, logging, faces and microfacies analysis. Results show that Songo Songo Island can be classified into three faces; the detrital reefs, organic reef and lime sand. The fossil assemblage reveals that most of the fauna and flora are frame-building organisms in organic reef. …

The Development Of Container Logistics In Intermodal Transport In South Africa : Training In Shipping, Makhubedu Donald

World Maritime University Dissertations

No abstract provided.

The Government's Role In Multimodal Development And Trade Facilitation In Tanzania, S. G.I. Tumpe Mwaijande

World Maritime University Dissertations

No abstract provided.

The Training Of Marine Engineers : Present Methods And Future Directions In Developing Countries (Africa), Yassin Magongo Songoro

World Maritime University Dissertations

No abstract provided.