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Journal of Geographic Information System 2012年第3期4卷 273-278页

作者： Julian Ijumulana Preksedis M. Ndomba College of Engineering and technology University of Dar es Salaam

The following article has been retracted due to the investigation of complaints received against it. The Editorial Board found that substantial portions of the text came from other published papers. The scientific community takes a very strong view on this matter, and the Journal of Geographic Information System treats all unethical behavior such as plagiarism seriously. This paper published in Vol.4 No.3 273-278, 2012, has been removed from this site.

关键词： Image Objects Spatial Uncertainty Spatial Change Detection Remote Sensing Time Series

Performance of a Large-Scale Medical Waste Incinerator in a Referral Hospital

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Engineering（科研） 2015年第10期7卷 676-690页

作者： Veilla E. Matee Samwel V. Manyele Department of Chemical and Mining Engineering University of Dar es Salaam Dar es Salaam Tanzania

The aim of the study was to analyze the performance of large scale incinerator installed in a referral hospital. The study involved weighing and loading infectious waste of different composition (sharps and other waste), recording temperatures in the primary and secondary chamber with time, fuel used and collecting and weighing the bottom ash for 65 days. The analysis shows that the incinerator on average uses 362 L/day (45 L/h) to incinerate 945 kg of medical waste (40.8 kg/day of sharps waste and 904 kg/day of other waste), generating 51.2 kg of ash daily. The observed fuel consumption rate was too high necessitating corrective action. The average weight reduction was 94.6%. The study shows that the average sharps waste composition for medical waste incinerated was 4.3% and other waste was 95.7%. The incinerator capacity ranged between 100 and 130 kg/h. The fuel effectiveness ranged between 2.0 and 3.0 liters of diesel per kg of waste incinerated. The fuel effectiveness increased linearly with total waste incinerated and incinerator capacity, respectively, depending on the fuel consumption rate.

关键词： Medical Waste Incinerator Large-Scale Incinerator Sharps Waste Fuel Consumption Fuel Effectiveness Incinerator Capacity Incinerator Ash

Phylogenetic relationships among small barbus,barbus(actinopterygii: Cyprinidae) from malagarasi and Pangani river basins, Tanzania

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Natural Science 2013年第12期5卷 1249-1254页

作者： Chacha J. Mwita Department of Aquatic Sciences and Fisheries University of Dar es Salaam Dar es Salaam Tanzania

The phylogenetic relationships among “Barbus” species (Barbus jacksonii, B. paludinosus and B. trimaculatus) from Malagarasi and Pangani River systems were examined by partial mitochondrial cytochrome b (cyt.b) gene. Sequences of the same samples from elsewhere in Africa obtained from the South African institute of Aquatic Biodiversity (SAIAB’s) collection were also included in the analysis. Molecular technique was necessary due to phenotypic plasticity and extensive overlap of morphological features among the “Barbus species”. The findings of this study revealed that B. paludinosus from hale and Pangani populations occurred in two distinct genetic lineages though separated by a distance of approximately 10 km apart. Similar results were also noted amongst the population of B. paludinosus in Songati and Muumbara located on Lake Sagara in Malagarasi River basin. B. trimaculatus and B. jacksonii were indistinguishable such that it is envisaged that the two species are one and the same. The Barbus spp. from Africa included in the current study showed genetic affinity to neither European Barbus spp. nor South African redfins of the Pseudobarbus to conclude that the studied species of barbs are taxonomically quite different that needs further investigation to warrant renaming.

关键词： Phylogenetic Relationship Barbus Species Malagarasi and Pangani Systems Tanzania

The Community of Parasites Infecting Clarias gariepinusin the Tanzanian Waters: A Case of Lake Victoria

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Open Journal of Ecology 2014年第14期4卷 873-882页

作者： Chacha John Mwita Department of Aquatic Science and Fisheries University of Dar es Salaam Dar es Salaam Tanzania

Quantitative variations in parasites were investigated with respect to sex and size of Clarias gariepinus, season and localities sampled. Parasitic infection in male and female fish was not significantly different;prevalence (Man-Whitney paired sample test, U = 135.5, p = 0.7697), mean intensity (U = 136, p = 0.7829). Based on Kruskal-Wallis test analysis, the prevalence and mean intensity of five parasite species varied significantly among the three localities sampled. Adult parasites in Clarias gariepinus showed high abundance during the dry season while the larval forms showed high abundance in the wet season. In most of the parasite species analyzed the abundance varied significantly with host size. The abundance of Dolops ranarum, Paracamallanus cyatopharynx and Eumasenia bangweulensis for instance, increased with fish size, while that of Diplostomum mashonense, Tylodelphys species, Astiotrema reniferum, piscicolid leeches and Monobothrioides woodlandi increased initially but decreased as fish length reached 31 - 40 cm. Total parasite burden increased in fish of 20 - 40 cm standard length. Generally, most parasites were highly overdispersed and the negative binomial model described their distribution.

关键词： Population Biology Parasites Clarias gariepinus Lake Victoria Tanzania

Past, Present and Future Perspectives of Rice Production in Tanzania

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Agricultural Sciences 2023年第8期14卷 987-1006页

作者： Constantine Busungu Department of Crop Science and Beekeeping University of Dar es Salaam Dar es Salaam Tanzania

Cultivated rice (Oryza sativa L. and Oryza. glaberrima) is one of the most important food crops in the world. World rice production has increased three times since the green revolution. However, climate change and global warming effects as well as ever increasing world population will require the world to produce more rice without increasing area under rice production in order to meet those demands. The best option to overcome these challenges includes adoption of climate-smart technologies and sustainable solutions to rice production. Rice was probably introduced in Tanzania over 1000 years ago by Asian traders during trade contacts between Asia and East Africa Coast through Indian Ocean. Rice cultivation had been restricted to coastal area until 19th century when it started spreading to interior areas of Tanzania. During colonial period (1880s-1960s), the emphasis was to produce cash crops as raw materials for industrialized world. After independence production of rice increased significantly. Currently, rice is the second most important food crop in Tanzania after maize and Tanzania is the leading producer of rice in East African countries. It ranks 4th and 22nd in Africa and World respectively in terms of rice production. In this paper, the rice history, ecosystems, challenges and future perspective for sustaining rice production in Tanzania is reviewed.

关键词： Rice Production History Ecosystems Challenges Perspectives Tanzania

Distribution and Speciation of Heavy Metals in Water and Sediments of the Coastal Marine Areas of Tanzania

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Journal of Environmental Protection 2021年第10期12卷 734-754页

作者： Sharifa Omar Bungala John Machiwa Daniel Shilla Department of Aquatic Sciences and Fisheries University of Dar es Salaam Dar es Salaam Tanzania

The present study investigated the concentration and species of heavy metals As, Hg, Cr, Pb and Zn in water and As, Hg, Cr, Pb and Zn in sediments collected along the coastal marine areas of Tanzania so as to determine their behaviour and remobilization potential in the environment and the degree of their availability to edible aquatic biota for monitoring purposes. Sequential extraction revealed the presence of a significant proportion of heavy metals Cr, Pb and Zn bound to available fractions of sediments. Arsenic had the highest concentration in non available residual fractions. PCA analysis found that As-Hg, Cr-Pb were strongly correlated and that the two may be derived from the same source most likely from storm water drainage of waste water discharges, while Zn may have come from the different source like watershed erosion. Further, PCA clearly confirms the same. Generally, Zn among all heavy metals analysed was the most available to aquatic biota due to its higher average concentrations in the acid soluble fraction, followed by chromium. However, high percentages of metal species studied in Tanzania coastal marine areas were found in non available fractions which indicated that the edible aquatic biota was safe for human consumptions.

关键词： Heavy Metals Sediment Sequential Extraction Speciation Bioavailable

Metazoan Parasites of Clariid Fishes, Lake Victoria: Reflection of the Original Fauna in the Lake?

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Natural Science 2014年第9期6卷 651-658页

作者： Chacha J. Mwita Department of Aquatic Sciences and Fisheries University of Dar Es Salaam Dar Es Salaam Tanzania

A total of 32 parasite species were documented from 658 clariid fishes examined. Thirteen species were nematodes, eleven digeneans, three cestodes, two crustaceans, and the Monogenea, Acanthocephala and Hirudinea were each represented by one species. Of the parasites recovered 16 were identified to species level, 12 to genus and 4 parasites were not identified. Most of the parasites recorded in the present study have been reported in fish ofTanzaniaand elsewhere, however, there were a few first records, and these included Neogoezia sp., Comephoronema sp., Travnema sp., Quimperia sp. and Gendria tilapiae. It is stipulated that these parasites represent the original fauna of the lake prior to introduction of the alien species. The clariid fish species investigated were a good model for studying the parasites of fish in the lake because of having a variety of parasites some of which being specific to certain clariid fishes, for instance Diplostomum and Tylodelphys species infecting only C. gariepinus and the camallanids being typical of the clariid fishes.

关键词： Metazoan Parasites Clariid Fishes Lake Victoria Tanzania

Evaluation of Accuracy of Clinical Examination and MRI on Diagnosing Anterior Cruciate Ligament and Meniscal Tears in Comparison to Diagnostic Arthroscopy among Patients Attending at Muhimbili Orthopedic institute

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Open Journal of Orthopedics 2021年第12期11卷 353-370页

作者： Hellen Machagge Felix Mrita Mohamed Muhamedhussen Billy Haonga Cuthbert N. Mcharo Muhimbili Orthopedic institute Dar-es-Salaam Tanzania Muhimbili University of Health and Allied Sciences Dar-es-Salaam Tanzania Ebrahim Haji Charitable Health Centre Dar-es-Salaam Tanzania

Routine use of Magnetic Resonance Imaging (MRI) as screening test after clinical diagnosis for meniscal and/or anterior cruciate ligament (ACL) has a detrimental effect on patients in limited resourced countries. This study was done to compare accuracy of clinical examination and that of (MRI) on diagnosing meniscal and or (ACL) tears. Methodology: A cross-sectional-descriptive study was done on 57 knees of patients. Clinical examination, MRI and then diagnostic arthroscopy, as the gold standard, were done to all the cases. Results were recorded;the accuracies of MRI and clinical examination were evaluated and their results were compared. Results: Median age of patients was 40 years. Clinical examination had sensitivity of 93.62% and specificity of 40% for diagnosing meniscal tears;and sensitivity of 100%;and specificity of 97.67% for diagnosing ACL tear. MRI had sensitivity of 85.11%, and specificity of 40% for meniscal tear diagnosis and 71% and 100% respectively for ACL tear diagnosis. Diagnostic accuracy was 84.21% for meniscal and 98.24% for ACL tears by clinical examination and by MRI was<

关键词： MRI Clinical Examination Diagnostic Accuracy ACL Meniscal

Analysis of Temperature Profiles and Cycle Time in a Large-Scale Medical Waste Incinerator

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Engineering（科研） 2015年第10期7卷 717-732页

作者： Veilla E. Matee Samwel V. Manyele Department of Chemical and Mining Engineering University of Dar es Salaam Dar es Salaam Tanzania

Temperature profiles and cycle times in a large-scale medical waste incinerator installed in a referral hospital were used to assess the performance and functionality of incinerator. The study was conducted using data collected from 8 cycles per days for 67 days. For proper combustion and destruction of toxic components in the primary chamber and destruction of pollutants and toxic components in the flue gas, it is desired to reach the maximum temperature in the chambers faster and maintain this maximum temperature for an extended time interval. The primary and secondary temperatures T1 and T2, respectively, were recorded at an interval of one minute for different cycles. Different amounts of wastes with varying proportions of sharps and other wastes were loaded into the incinerator and temperature profiles recorded. The analysis shows that the incinerator works at primary temperature less than the required recommended by manufacturer while the secondary chamber operates between 600 and above 950℃, although higher temperatures up to 1020℃ were observed. The average load preparation time was observed to be 14.6 minutes, while the chamber preheating time before daily initial loading was 25.45 minutes. Both temperature profiles were observed to have similar shapes for all combustion cycles studied, except when incinerator malfunctioning occurred. The average cycle time was established to be 32.7 minutes and 28.97 minutes based on time to drop to 550℃ after the maximum temperature and loading time intervals, respectively, although longer cycle times were observed. Temperature drop in both combustion chambers as a result of waste charging was observed in the interval of 5 minutes. The chamber heating rate was observed to decrease exponentially with time during both preheating and incineration operation.

关键词： Medical Waste Management Infectious Waste Pathological Waste Sharps Waste Incineration Temperature Profile Cycle Time Heating Rate

Dynamics of Nitrogen Transformation and Removal in a Pilot High Rate Pond

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Journal of Water Resource and Protection 2014年第5期6卷 433-445页

作者： Aloyce W. Mayo Emmanuel E. Hanai Department of Water Resources Engineering University of Dar es Salaam Dar es Salaam Tanzania

The transformation and removal of nitrogen was studied in a pilot high rate pond with a surface area of 10.2 m2 and water depth of 60 cm. The pilot unit received wastewater from an existing field scale primary facultative pond at the University of dar es salaam. Wastewater samples were collected from the influent and effluent of high rate pond and were analyzed for physical-chemical parameters in the laboratory and in situ. An appropriate model complexity was selected, from which a conceptual model was then developed to model various processes in the system using STELLA 6.0.1 software. The study demonstrated that dominant nitrogen transformation processes in HRP were nitrification and denitrification, which transformed 0.95 and 0.87 gN/m2·d, respectively. These were followed by mineralization (0.37 gN/m2·d), ammonia uptake by microorganisms (0.34 gN/m2·d), volatilization (0.30 gN/m2·d), sedimentation (0.24 gN/m2·d), and regeneration (0.15 gN/m2·d). Uptake of nitrate was not observed because of microorganisms preference for ammonia, which was abundant in the pond. The major nitrogen transformation mechanisms in high rate pond were denitrification, net sedimentation and volatilization, which accounted for 69.1%, 7.1% and 23.8% of the total permanent removal mechanisms of nitrogen in High Rate Pond.

关键词： High Rate Ponds Nitrification Denitrification Nitrogen Transformation Nitrogen Removal