Digital Commons Network^™

Implementation Of A Tabu Search Heuristic For The Examinations Timetabling Problem, A. R. Mushi

Tanzania Journal of Science

This paper reports on the design and implementation of an algorithm for the construction of an examinations timetable. The Examinations Timetabling Problem is the problem of assigning examinations and candidates to time periods and examination rooms while satisfying a set of specific constraints. Every University has a different set of constraints and structure of examinations. Generally, timetabling problems are NP-Hard and therefore very difficult to solve. However, they are of great interest due to their important practical application in educational institutions. This paper discusses a heuristic algorithm basing on the examinations timetabling at the University of Dar es salaam. The …

Evaluation Of Single-Step Steam Pyrolysis-Activated Carbons From Lesotho Agro-Forestry Residues, I. Hapazari, V. Ntuli, W. Parawira

Tanzania Journal of Science

Activated carbon has been widely used worldwide as an effective filtration or adsorption material for removing biological and chemical contaminants from drinking water. The potential of producing activated carbon (AC) from local agroforestry residues by single-step steam pyrolysis processes was investigated. The research aims to promote innovative use of local raw materials and relatively low-cost techniques in production of activated carbon. Four varieties of activated carbons from four different agroforestry residues, pine (Pinus contorta) cones (PC), Abies (Abies cilicica) seeds (AS), maple (Acer ginnala) seeds (MS) and peach (Prunus persica) stones (PS), were prepared and evaluated. The ACs were evaluated …

A Study Of Sponge Aquaculture In Jambiani: Is Shallow Farming Feasible?, Sarah Friday

Independent Study Project (ISP) Collection

In the village of Jambiani, Unguja, a Swiss NGO called Marine Cultures has established an experimental sponge farming initiative to improve local employment and support economic development. Currently, the main farming site is only accessible through SCUBA diving. This is consistent with experimental farm sites in other oceanic regions, as most are located in depths of at least five meters with sponges suspended vertically to maximize water flow exposure. Farms located in shallower water may not be conducive to sponge growth due to highly variable environmental conditions; however, no conclusive research has been conducted on this matter (Duckworth 2009). Nonetheless, …

Seaweed Farmer Education: Is It Enough To Sustain The Industry? Analyzing The Status Of Stakeholder Investment In Muungoni And Jambiani, Unguja, Erika Davis

Independent Study Project (ISP) Collection

Since Filipino researchers arrived in Zanzibar to determine the potential for cultivation of seaweed more than 20 years ago, the islands' coastal communities have relied on the resource as a main or alternative source of income. When the companies started investing at the industry’s onset, trained personnel offered farmers' education on proper farming techniques for Spinosum (Eucheuma denticulatum) and Cottonii (Kappaphycus spp.) by establishing demonstrative (demo) farms and holding seminars. Today, informal training involves experienced farmers teaching the newcomers their techniques. While demo farms remain in some villages, companies offer no extension services based on the belief that the farmers …

I. The Synthesis And Coordination Chemistry Of Novel 6Π-Electron Ligands. Ii. Improvement Of Student Writing Skills In Chemistry Lab Reports Through The Use Of Calibrated Peer Review, Wilson Ngambeki William

Chemistry and Chemical Biology ETDs

ABSTRACT I

The goal of this study was to synthesize and characterize a set of coordination complexes containing 6π-cationic ligands. These compounds could be extremely useful as catalysts for the polymerization of olefins that are widely used in the synthetic polymer industry. The original strategy was to synthesize the 6π-cationic ligands using (Ph₂P)₃CH (1) and (Me₂P)₃CH (10) as precursors; however, both precursors 1 and 10 were found to be highly reactive leading to the fragmentation products (Ph₂P)₂CH₂ and (Me₂P)₂CH₂ respectively. In trying …

Quantitative Structure-Property Relationships For Predicting Chlorine Demand And Disinfection Byproducts Formation In Drinking Water, Gebhard Balthazar Luilo

Chemistry and Chemical Biology ETDs

Models are important tools for designing or redesigning water treatment processes and technologies to minimize disinfection byproducts (DBPs) formation without compromising disinfection efficiency. Empirical models, which are the most common, are based on bulk water quality parameters that vary with time and space. These parameters may not always have linear relationships with chlorine demand and DBPs formation which make structure-based models more attractive to study. In this dissertation, Quantitative Structure-Property Relationship (QSPR) models which make use of structural properties of individual molecules were developed using experimental data obtained from the literature. The amounts are reported in moles of chlorine (HOCl) …

Spectroscopic And Electronic Structure Studies Of Bis-Metallodithiolenes, Regina Peter Mtei

Chemistry and Chemical Biology ETDs

Dimethylsulfoxide reductase (DMSOR) enzyme family members catalyze oxygen atom transfer to or from organic or inorganic substrate and play important roles in the global cycles of sulfur and nitrogen, as well as the detoxification of arsenite. This enzyme has recently been subject of investigation due to its catalytic nature of oxygen atom transfer. This work reports on the electronic structure and reactivity properties of dimethylsulfoxide reductase enzyme studied using spectroscopic and computational methods. The spectroscopic methods included electronic absorption (EA), electron paramagnetic resonance (EPR), magnetic circular dichroism (MCD) and resonance Raman rRaman). Here, we report full characterization of the DMSOR …

Spectroscopic And Electronic Structure Studies Of Metalloenzyme Active Sites, Joseph Sempombe

Chemistry and Chemical Biology ETDs

This work reports on the electronic and geometric structural studies of xanthine oxidoreductase (XO), S-ribosylhomocysteinase (LuxS) and inducible nitric oxide synthase (iNOS) active sites resulting from the joint applications of electronic absorption, electron paramagnetic resonance and magnetic circular dichroism spectroscopic methods. XO catalyzes formal oxygen atom insertion into a substrate C-H bond, but differs from monooxygenase enzymes in that the inserted oxygen atom derives from metal activated water and reducing equivalents are generated rather than consumed. Studies on aldehyde inhibited' XO (a paramagnetic form observed during XO catalysis), analyzed in terms of the relationships between the g-, ^95,97Mo hyperfine, …

Wood Usage In Rural Tanzania: An Investigation Into The Sources And Accessibility Of Fuelwood And Polewood For The Residents Of Kizanda Village, West Usambara Mountains, James Ray

Independent Study Project (ISP) Collection

This study was conducted over the course of 16 days between April 8^th and 28^th in Kizanda village, which borders the protected Baga Government Forest Reserve, in the West Usambara Mountains in Northern Tanzania. The goals of this study were to investigate the actual sources of fuelwood and polewood reported by the people of Kizanda village, to determine if these sources offer a sufficient amount of fuelwood and polewood, and to identify possible sustainable alternatives to wood products from the Baga Government Forest Reserve and other protected forest areas near Kizanda village. Key informant interviews (n = 9) …

Biogas Technology On Uzi Island, Zanzibar: A Feasibility Study, Peter J. Mcinerney

Independent Study Project (ISP) Collection

With realization of the finite quantity of fossil fuels and improved study on the effects of global climate change there has been an increasing demand for energy production from renewable, sustainable sources in developed and developing nations alike. The population of Tanzania relies overwhelmingly on biomass as a source of primary energy, with such impacts as deforestation and negative health effects. Biogas generation is a renewable energy technology that utilizes organic waste sources to produce a methane-rich gas suitable for cooking and lighting with the potential to replace current unsustainable energy sources and provide several environmental and socioeconomic benefits. A …

Studies On Group 10 Pincer Carbene Metal Complexes, Agnes Mrutu

Chemistry and Chemical Biology ETDs

Selective oxidation chemistry is a topic of intense interest worldwide, in particular when using molecular oxygen (O₂) directly as the oxidizing species. The primary reason for using O₂ rather than other oxidants is to take advantage of the inexpensive nature of oxygen; however, the radical ground state of O₂ leads to non-selective reactions with organic substrates. As such, basic knowledge and understanding involving the fundamental reactions of O₂ with organometallic species will be required in order to overcome this lack of selectivity. The work presented in this dissertation has two main research goals to help …

Phylogenetic Relationships Of The Metazoan Parasites Of The Clariid Fishes Of Lake Victoria Inferred From Partial 18s Rdna Sequences, C. J. Mwita, G. Nkwengulila

Tanzania Journal of Science

Phylogenetic relationships among twenty two metazoan parasites recovered from seven species of clariid fish from Lake Victoria were analysed using partial 18S rDNA sequences. The 18S rDNA gene was amplified by polymerase chain reaction, directly sequenced, aligned and phylogenies inferred using maximum parsimony. Heuristic bootstrap MP searches yielded one most parsimonious tree (CI = 61%, HI = 39%), which showed that clariid parasites are monophyletic at higher taxonomic levels (Cestodea, Nematodea, Digenea and Crustacea). However the position of two trematodes (Allocredium mazoensis and Clinostomum sp.) and a nematode (Contracaecum sp.) were not stable. Despite the present findings, the study utilised …

The Major Cause Of Observed Erosion Surge On The Beaches North Of Dar Es Salaam City, N. Nyandwi

Tanzania Journal of Science

Surges in coastal erosion north of Dar es Salaam city have been documented from 1977 to the early 1980s and around 1997/98. Analysis of the wind data shows that the documented increase in coastal erosion coincided with increased wind speeds. Extreme winds in excess of 10-11 m s-1 were experienced during 1976-78, 1984 and after 1996. Their coincidence with extreme high tides produced the high erosion rates. Using beach profile data for the years 1998-2000 the evolution of the beach profile with the changing monsoon winds and sediment input by rivers could be demonstrated. The beach erosion took place during …

African Water: An Experience With Project Management In Bulima, Tanzania, Robert Sharp

Honors Theses

Details the author's experiences researching, designing, and implementing a water system for a boarding school in Africa.

Conservation From The Bottom-Up: Human, Financial, And Natural Capital As Determinants Of Resilient Livelihoods In Kigoma Rural, Tanzania, Yared J. Fubusa

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Rhetoric of "community-based conservation" has gained prominence among development specialists and environmentalists, yet such projects are often implemented from the top-down in Africa. This dissertation contends that only a bottom-up approach can foster resilient livelihoods and environmental stewardship.

This study focused on determinants of household resilience within a poverty-stricken agricultural community near Gombe Stream National Park (GSNP) in western Tanzania. The research purpose was to explore: 1) relationships between villagers and GSNP management; 2) how groups and individuals view priority livelihood problems and solutions; 3) various attributes of households; and 4) perceived trends for household resilience and how these are …

The Determinants Of Colorectal Cancer Survival Disparities In Nevada, Lucas N. Wassira

UNLV Theses, Dissertations, Professional Papers, and Capstones

Different population groups across Nevada and throughout the United States suffer disproportionately from colorectal cancer and its after-effects. Overcoming cancer health disparities is important for lessening the burden of cancer. There has been an overall decline in the incidence of and mortality from colorectal cancer (CRC). This is likely due, in part, to the increasing use of screening procedures such as Fecal Occult Blood Test (FOBT) and/or endoscopy, which can reduce the risk of CRC mortality by fifty percent. Nevertheless, screening procedures are routinely used by only fifty percent of Americans aged fifty years and older. Despite overall mortality decreasing …

Pesticide Use And Awareness On Pemba Island, Brooke Shorett, Lauren Crask

Independent Study Project (ISP) Collection

Use and awareness of pesticides by 301 farmers on Pemba Island, Tanzania, were surveyed, in order to assess practices and perceptions of pesticide use. Surveys were conducted in both peri-urban farms and rural farms, which were either irrigated or rain-fed. Results showed that while the overwhelming majority of farmers on irrigated fields used pesticides frequently, farmers located in rain-fed irrigation largely farmed without pesticides. Likewise, peri-urban farmers made use of pesticides far more than rural farmers. Of the farmers who did use pesticides, an average of Tsh 17,219 was spent annually on Rogol, Satunil, Dimethoate, Simithion, Thionex and Dursban. Most …

Stop Pummeling My Primates: Effects Of Land Use Change On Behaviors Of Papio Anubis Near Lake Manyara National Park In Mto Wa Mbu, Tanzania, Hannah Young

Independent Study Project (ISP) Collection

The ever-increasing human population means more land is required for housing and agricultural needs to sustain the growing population. This study involves a group of olive baboons living in and on the boundary of Lake Manyara National Park in Mto wa Mbu, Tanzania. They leave the park everyday and travel to surrounding areas. There are three different habitats near the baboons’ exit point of the park, a residential area with houses and some people, an undisturbed area without homes and residents, and an agricultural area, full of farms and the most densely populated area. The object of this study was …

Upwelling Couples Chemical And Biological Dynamics Across The Littoral And Pelagic Zones Of Lake Tanganyika, East Africa, Jessica R. Corman, P. B. Mcintyre, B. Kuboja, W. Mbemba, D. Fink, C. W. Wheeler, C. Gans, E. Michel, A. S. Flecker

School of Natural Resources: Faculty Publications

We studied the effects of upwelling on nutrient and phytoplankton dynamics in the pelagic and littoral zones of Lake Tanganyika near Kigoma, Tanzania. During the dry season of 2004, a rise in the thermocline and sudden drop in surface water temperatures indicated a substantial upwelling event. Increases in concentrations of nitrate, soluble reactive phosphorus, and silica in the surface waters occurred simultaneously after the temperature drop. Within days, chlorophyll a concentrations increased and remained elevated, while inorganic nutrient concentrations returned to preupwelling levels and organic nutrient concentrations peaked. We observed parallel temporal patterns of water temperature, nutrient concentrations, and phytoplankton …

Retrieval Of Atmospheric Elemental Carbon Records Using Lake Sediments : Implications In Radiative Forcing, Tanveer Ahmed

Legacy Theses & Dissertations (2009 - 2024)

Elemental or black carbon (EC or BC) aerosols produced during incomplete combustion strongly absorb solar radiation and contribute to global warming, and cause cardiopulmonary disease. Long-term atmospheric EC measurements, [EC]_atm, are needed to validate global climate models to estimate the impact of EC on earth's temperature. Such data is sparse.

Tetrapod Fauna Of The Lowermost Usili Formation (Songea Group, Ruhuhu Basin) Of Southern Tanzania, With A New Burnetiid Record, Christian A. Sidor, Kenneth D. Angielczyk, D. Marie Weide, Roger M. H. Smith, Sterling J. Nesbitt, Linda A. Tsuji

Department of Earth and Atmospheric Sciences: Faculty Publications

Vertebrate fossils from the Ruhuhu Basin of southern Tanzania have been known for over 75 years, but the details of their stratigraphic distribution remain imperfectly understood. Recent fieldwork in the Upper Permian Usili Formation (Songea Group) has led to the discovery of a tetrapod assemblage in a conglomeratic unit at its base. The fossils are concentrated in matrix-supported intraformational clay pebble conglomerates interpreted as mass flow deposits in wide, shallow channels in the distal reaches of an alluvial fan. Included in this new collection are fossils representing the first record of a burnetiid therapsid from Tanzania. The anatomy of the …

The Price Of Water: Assessment Of The Current Water Situation And Recommendation Of Technical Methodology For The Community Of Shirati, Tanzania, Max Perel-Slater

Independent Study Project (ISP) Collection

This study looked at the current water situation in the community of Shirati Tanzania. It took place from November 7th – 27th 2009. My sample frame was the villages in the Roche District of the Mara Region in northeastern Tanzania. My sample populations consisted of residents of three villages – Mukoma, Nyamagongo, and Shirati-Sota. I applied a four prong approach to my data collection: 1) Eight Key Informant Interviews with three local village leaders and two medical officers of the local hospital and dispensary, two water engineers and one long time resident; 2) Ninety randomly selected surveys, 30 in each …

Summer/Fall 2009, Nsu Oceanographic Center

Currents

No abstract provided.

Serotonin Immunoreactive Cells And Nerve Fibers In The Mucosa Of The Rat Stomach, A P Gesase

Tanzania Journal of Science

The current study has showed the morphological features of serotonin (5-hydroxytryptamine) immunoreactivity in the pyloric mucosa of the rat stomach. The immunoreactive elements included the endocrine cells, mast cells and mucosal nerve fibers in the lamina propria. The immunopositive endocrine cells were oval in shape and located mostly in the basal part of the gastric glands. The cell contained a central non-staining area and the peripheral staining zone. The mast cells stained homogenously and appeared to be oval-round in shape. They were located in the upper, middle and basal parts of the mucosa. Serotonin immunoreactive nerve fibers with varicosities were …

Morphological Features Of Tyrosine Hydroxylase Immunoreactive Cells In The Mouse Islets Of Langerhans, A P Gesase, Y -I Satoh

Tanzania Journal of Science

The current immunohistochemical study used the antibody against tyrosine hydroxylase (TH) to observe the immunoreactive elements in the mouse pancreas. The results indicated the presence of immunoreactive nerve fibers and endocrine cells. The immunopositive nerve fibers appeared as thick and thin bundles; thick bundles were seen to run along the blood vessels giving out fine fibers to the wall. Varicose nerve fibers were seen in the islets of Langerhans and also in close association with the exocrine endpieces. The TH immunoreactive cells were oval-round in shape and some showed the central non-staining area and the dense staining peripheral zone. More …

Mercury Contamination In Domestic Ducks In Geita, Northwest Tanzania, C Kinabo, H Lyatuu

Tanzania Journal of Science

Total mercury concentrations (THg) were determined in domestic ducks (Anas platyrhncha) tissues in Mgusu Village, Geita District NW Tanzania. Elevated mercury levels were found in all tissue samples and showed a trend of increasing mercury concentration with weight/age of the poultry. Highest total mercury (THg) levels (mg/kg) in domestic ducks were found in liver (ducklings: 30.5; juvenile: 254.1; mature ducks: 590.2), followed by gizzards (ducklings: 45.9; juvenile: 230.3; mature: 254.6), lungs (ducklings: 12.2; juvenile: 29.1; mature: 46.9) and feathers (ducklings: 0.1; juvenile: 62.1; mature: 198.3). Corresponding THg statistical values (mg/kg) for the tissues increased with age and weight. Highest THg …

Physico-Chemical Characteristics Of Storage-Ripened Mango (Mangifera Indica L.) Fruits Varieties Of Eastern Tanzania, O C Othman, G P Mbogo

Tanzania Journal of Science

Two mango (Mangifera indica L.) fruit varieties, Dodo and Viringe, from two localities of Eastern Tanzania, (Muheza in Tanga and Ifakara in Morogoro), were harvested as mature green fruits during early, mid and late season and allowed to ripen while stored at room temperature. The fruits were analyzed for their proximate composition (ash, titratable acidity, crude fat, crude fibre, moisture), reducing and total sugars content, ascorbic acid and total soluble solids content, concentration of four macro elements (Ca, Mg, K, Na) and seven heavy metals (Al, Cd, Cu, Fe, Mn, Pb, Zn). The results showed that the mango fruits had …

Physical And Chemical Composition Of Storage-Ripened Papaya (Carica Papaya L.) Fruits Of Eastern Tanzania, O C Othman

Tanzania Journal of Science

The proximate composition (ash, titratable acidity, crude fat, crude fibre, moisture and sugars), soluble solids, ascorbic acid, polyphenol oxidase activity, macro-nutrients and heavy metal contents of storage-ripened papaya (Carica papaya L.) fruits from Mbezi, Dar es Salaam, Tanzania were determined. The determinations were repeated for early, middle and late-season papaya fruits. The fruits were always harvested at the mature green stage and allowed to ripen during room temperature storage. The results showed that papaya fruits had high moisture content (>85.5%), low acidity (<0.18% c.a.), low crude fat (0.10 g/100 g-edible portion), moderate crude fibre (1.45 g/100 g-edible portion), high ascorbic acid content (>84.5 mg/100 g- fw), moderate total sugars (>13.0%) and soluble solids (>12.9%) content. Early-season …

Plants As A Source Of Green Corrosion Inhibitors: The Case Of Gum Exudates From Acacia Species (A. Drepanolobium And A. Senegal), J Buchweishaija

Tanzania Journal of Science

The inhibitive performance of gum exudates from Acacia drepanolobium and Acacia senegal from Tanzania, towards the corrosion of mild steel in fresh water has been investigated. The experimental methods include potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) studies. The results indicate that gum exudates (Acacia drepanolobium and Acacia senegal) exhibit good inhibition characteristics to corrosion on mild steel under fresh water medium and the inhibition efficiency of up to 90.7% and 99.7% respectively was attained at 30 oC. Furthermore, the studies have shown that the inhibition performance remained above 90% on both Acacia exudates independent of the raise in temperature. …

Synthesis And Coordination Chemistry Of New Oxazoline And Benzoxazole Based Ligands With Lanthanides, Edicome Cornel Shirima

Chemistry and Chemical Biology ETDs

In Chapter 1, a brief literature review on the chemistry of lanthanides (Ln) and actinides (An) is described. In addition, the coordination chemistry of lanthanides/actinides with various ligands comprised of organic backbones has also been described. In Chapters 2 and 3 the syntheses of oxazoline and benzoxazole ligands is described. Both ligands contain a hard donor group (P=O) and the nitrogen (N) atom from the heterocycle as a relatively softer donor atom. In Chapter 2 the oxazoline ligand was synthesized in two steps reaction that involves substitution with Ph₂P group and oxidation of the phosphine into P=O by …