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Effects Of Aluminium And Tungsten Co-Doping On The Optical Properties Of Vo2 Based Thin Films, Cephas J Lyobha, Nuru R Mlyuka, Margaret E Samiji
Effects Of Aluminium And Tungsten Co-Doping On The Optical Properties Of Vo2 Based Thin Films, Cephas J Lyobha, Nuru R Mlyuka, Margaret E Samiji
Tanzania Journal of Science
Aluminium and tungsten co-doped vanadium dioxide (VO2:W:Al) thin films were deposited by DC reactive magnetron sputtering technique. In this work we report on the effects of aluminium and tungsten co–doping on the optical properties of vanadium dioxide (VO2) based thin films with a view of combining both increased luminous transmittance (Tlum) and lowered transition temperature (τc). The effect of aluminium and tungsten co-doping on semiconductor-metal transition of vanadium dioxide films was investigated and compared with tungsten doped and undopedVO2films. Spectral transmittances of the films were obtained using Shimadzu SolidSpec-3700 DUV UV-VIS-NIR spectrophotometer. The results revealed that the transmittance of tungsten …
Hall Effect Parameters Of Aluminium And Tungsten Co-Doped Vo2 Thin Films, Mohamed Mussa, Nuru R Mlyuka, Margaret E Samiji
Hall Effect Parameters Of Aluminium And Tungsten Co-Doped Vo2 Thin Films, Mohamed Mussa, Nuru R Mlyuka, Margaret E Samiji
Tanzania Journal of Science
The Hall Effect parameters of Al and W co-doped VO2 thin films were studied in order to explain the effect of co-doping on the electrical properties of thermochromic VO2 films. The carrier concentrations and conductivity of the films were found to increase with increase in temperature while carrier mobility decreased reaching a minimum around the transition temperature then slightly rose and became stable at high temperatures. Tungsten doped films displayed higher carrier concentrations and conductivity on both sides of the metal insulator transition and lower mobility compared to undoped and Al and W co-doped VO2 thin films.
Effects Of Selenized Dc Sputtered Precursor Stacking Orders On The Properties Of Cu2znsnse4 Absorber Layer For Thin Film Solar Cells, Hezekiah B Sawa, Margaret E Samiji, Nuru R Mlyuka
Effects Of Selenized Dc Sputtered Precursor Stacking Orders On The Properties Of Cu2znsnse4 Absorber Layer For Thin Film Solar Cells, Hezekiah B Sawa, Margaret E Samiji, Nuru R Mlyuka
Tanzania Journal of Science
This study investigated the effects of selenized DC sputtered precursor stacking orders on the structural, electrical and optical properties of copper zinc tin selenide (CZTSe) absorber layer for thin film solar cells. The precursors were deposited sequentially on the soda lime glass substrate at room temperature by DC magnetron sputtering. The precursors were selenized by annealing in an atmosphere containing selenium pellets and nitrogen gas. The structural, morphological, optical and electrical properties were respectively characterized using X-Ray Diffractometer (XRD), atomic force microscopy (AFM), UV/VIS/NIR lambda 9/19 spectrophotometer, Hall Effect measurement system (HMS 3000) and a four point probe system. CZTSe …
Optimization Of Zinc To Tin Ratio In A Sol Gel Precursor Solution On The Growth And Properties Of Annealed Czts Thin Films, Justine John Tibaijuka, Margaret E Samiji, Nuru R Mlyuka
Optimization Of Zinc To Tin Ratio In A Sol Gel Precursor Solution On The Growth And Properties Of Annealed Czts Thin Films, Justine John Tibaijuka, Margaret E Samiji, Nuru R Mlyuka
Tanzania Journal of Science
CZTS thin films were deposited by sol–gel spin coating method using precursor solutions prepared by dissolving copper acetate dihydrate, zinc acetate dihydrate, tin chloride and thiourea in methanol and monoethylamine then annealed in RTP furnace at 500 °C. Sol–gel precursor solutions were prepared with different Zn/Sn in a precursor solution and were annealed at different time intervals; and their effects on the optical and electrical properties of CZTS (Cu2ZnSnS4) films were investigated. The optical band-gap values were estimated to be between 1.30 and 1.88 eV while the absorption coefficients were in the range of 104 cm–1 in the visible region. …
Compositional And Thickness Effects On The Optical Properties Of Zinc–Doped Selenium–Antimony Thin Films, Austine A Mulama, Julius M Mwabora, Andrew O Oduor, Cosmas M Muiva
Compositional And Thickness Effects On The Optical Properties Of Zinc–Doped Selenium–Antimony Thin Films, Austine A Mulama, Julius M Mwabora, Andrew O Oduor, Cosmas M Muiva
Tanzania Journal of Science
Chalcogenide system of antimony (Sb)-selenium (Se)-zinc (Zn) system is a promising semiconductor for phase change memory devices due to its thermal stability and low power consumption. The study investigated the effect of film thickness and zinc content on the optical properties of thermally evaporated Sb10Se90-xZnx (x = 0, 5, 10 & 15 at. %) thin films. It was found that transmittance (T~ 85-40%) and optical band gap energy (Eopt ~ 1.60 eV – 1.22 eV) decreased but absorption coefficient (α~0.840–2.031 104 cm–1) increased with increase in zinc content. Furthermore, as the film thickness increased from 53 ± 5 nm to …
Effects Of Thickness Variation In The Multilayer Thin Film On The Performance Of Eta Solar Cell, Robinson J Musembi
Effects Of Thickness Variation In The Multilayer Thin Film On The Performance Of Eta Solar Cell, Robinson J Musembi
Tanzania Journal of Science
A highly structured eta solar cell of the type TiO2/In(OH)xSy/Pb(OH)xSy/PEDOT:PSS/Au with different layer thickness has been fabricated using various deposition techniques for each layer in the stack. The solar cell parameters, Uoc, FF and have been extracted from current- voltage characteristics measurements. The buffer layer and the hole collector layer have been kept constant while the window and the absorber layer have been varied. The thickness of either of the two layers being varied has been observed to affect the performance of the solar cells. The difference in thickness has been attributed to affect the charge lifetime in the space …
Thermal Performance Of Selected Oils In Uganda For Indirect Solar Domestic Cooking Applications, Benard Tabu, Karidewa Nyeinga, Jimmy Chaciga, Denis Okello
Thermal Performance Of Selected Oils In Uganda For Indirect Solar Domestic Cooking Applications, Benard Tabu, Karidewa Nyeinga, Jimmy Chaciga, Denis Okello
Tanzania Journal of Science
This study experimentally evaluated the thermal performance of selected oils in Uganda for indirect solar domestic cooking applications. The oil samples used were refined sunflower oil, refined palm oil and thermia B. These oils are locally available in Uganda. Thermal stratification, energy and exergy analysis were performed for each oil to determine their suitability for Thermal Energy Storage (TES) using a thermosiphon principle. The results showed that thermal stratification of refined sunflower oil was higher as compared to refined palm oil and thermia B during the first one hour. The stored energy and exergy for refined sunflower oil was generally …
Effects Of Substrate Radial-Position Relative To The Sputter-Gun Axis On The Electrical, Optical And Structural Properties Of Zno Thin Films Deposited By Reactive Direct Current Magnetron Sputtering, John Paul Eneku, Tom Otiti, Julius Mwakondo Mwabora, David Horwat
Effects Of Substrate Radial-Position Relative To The Sputter-Gun Axis On The Electrical, Optical And Structural Properties Of Zno Thin Films Deposited By Reactive Direct Current Magnetron Sputtering, John Paul Eneku, Tom Otiti, Julius Mwakondo Mwabora, David Horwat
Tanzania Journal of Science
ZnO thin films were deposited using reactive direct current (dc) magnetron sputtering on glass substrates placed at seven variable radial positions (-1, 0, 1, 2, 3, 4 and 5 cm) relative to the sputter-gun (target) axis. A pure zinc target was used and sputtering carried out in argon and oxygen atmosphere with flow rates of 50 sccm and 6 sccm, respectively. XRD characterization showed that, all films crystallized homogeneously in the wurtzite phase with a strong (002) and a weak (004) orientations. Film crystallinity was very low at substrate positions located less than or equal to 1 cm from the …
Levels Of Heavy Metals In Selected Facial Cosmetics Marketed In Dar Es Salaam, Tanzania, Joseph Yoeza Naimani Philip, Silvia John, Othman Chande Othman
Levels Of Heavy Metals In Selected Facial Cosmetics Marketed In Dar Es Salaam, Tanzania, Joseph Yoeza Naimani Philip, Silvia John, Othman Chande Othman
Tanzania Journal of Science
The aim of this study was to determine the levels of heavy metals: lead, cadmium, copper, zinc, arsenic and mercury in facial cosmetics (lipstick, lip glossy, facial powder, foundation, eyeliner, eye shadow and mascara) which were purchased randomly in Dar es Salaam, Tanzania. The levels of lead, cadmium, copper and zinc were determined using Atomic Absorption Spectrometry (AAS). The levels of arsenic were determined using Hydride Generation Atomic Absorption Spectrometry (HGAAS), and levels of mercury were determined using Cold Vapour Atomic Absorption Spectrometry. Prior to determination of the concentration of heavy metals, the samples were acid digested. The average order …
The Efficacy Of Raw Malangali Kaolin Clay In The Adsorptive Removal Of Cadmium And Cobalt Ions From Water, Nyemaga Masanje Malima, Esther Hellen Lugwisha, Alinanuswe Simon Mwakaboko
The Efficacy Of Raw Malangali Kaolin Clay In The Adsorptive Removal Of Cadmium And Cobalt Ions From Water, Nyemaga Masanje Malima, Esther Hellen Lugwisha, Alinanuswe Simon Mwakaboko
Tanzania Journal of Science
The suitability of raw Malangali kaolin (RMK) clay for the removal of cadmium and cobalt ions from water was investigated using a batch technique whereas the characterization of adsorbent material was performed by XRD, XRF, ATR-FTIR and N2 physisorption techniques. Various experimental parameters were tested for the effectiveness of RMK in removing heavy metals whereby quantitative determination of both Cd2+ and Co2+ ions has shown that, the factors such as adsorbent particle size, solution pH, contact time, adsorbent dose as well as initial metal ion concentration had significant effects on the adsorption processes. The equilibrium data described by Langmuir and …
A Trans Influence And Π-Conjugation Effects On Ligand Substitution Reactions Of Pt(Ii) Complexes With Tridentate Pendant N/S-Donor Ligands, Grace A. Kinunda
A Trans Influence And Π-Conjugation Effects On Ligand Substitution Reactions Of Pt(Ii) Complexes With Tridentate Pendant N/S-Donor Ligands, Grace A. Kinunda
Tanzania Journal of Science
The rate of displacement of the chloride ligands by three neutral nucleophiles (Nu) of different steric demands, namely thiourea (TU), N,N’-dimethylthiourea (DMTU) and N,N,N,’N-tetramethylthiourea (TMTU) in the complexes viz; [Pt(II)(bis(2-pyridylmethyl)amine)Cl]ClO4, (Pt1), [Pt(II){N-(2-pyridinylmethyl)-8-quinolinamine}Cl]Cl, (Pt2), [Pt(II)(bis(2-pyridylmethyl)sulfide)Cl]Cl, (Pt3) and [Pt(II){8-((2-pyridylmethyl)thiol)quinoline}Cl]Cl, (Pt4) was studied under pseudo first-order conditions as a function of concentration and temperature using a stopped-flow technique and UV-Visible spectrophotometry. The observed pseudo first-order rate constants for substitution reactions obeyed the simple rate law. The results have shown that the chloro ligand in Pt(N^S^N) complexes is more labile by two orders of magnitude than Pt(N^N^N) complexes due to the high trans labilizing …
Levels Of Heavy Metals In Deposited Dust And Soil From Selected Primary Schools In Dar Es Salaam, Joseph Yoeza Naimani Philip, Eliamini Ismail Mkenga, Othman Chande Othman
Levels Of Heavy Metals In Deposited Dust And Soil From Selected Primary Schools In Dar Es Salaam, Joseph Yoeza Naimani Philip, Eliamini Ismail Mkenga, Othman Chande Othman
Tanzania Journal of Science
The objective of this study was to examine the levels of heavy metals, lead, manganese, nickel, copper, chromium and cadmium in standard one and kindergarten classroom dusts and playing ground soils from selected primary schools along Morogoro road highway (Kimara, Mbezi, Kibamba and Kiluvya primary schools) and away from Morogoro road highway (Makabe, Msumi and Mbopo primary schools) as well as in the Dar es Salaam city center (Uhuru, Mzimuni, Dr. Omari Ali Juma, Manzese and Ubungo National House primary schools), Tanzania. The samples were acid digested and the supernatant analyzed using inductively coupled plasma optical emission spectrometer (ICP-OES). The …
Semisynthesis Of A Mellein-Type 3,4-Dihydroisocoumarin From Cashew Nut Shell Liquid (Cnsl), Clarence A. Mgina, Fatma Kadir
Semisynthesis Of A Mellein-Type 3,4-Dihydroisocoumarin From Cashew Nut Shell Liquid (Cnsl), Clarence A. Mgina, Fatma Kadir
Tanzania Journal of Science
Mellein-type 3,4-dihydroisocoumarin 39 (i.e., 8-methoxy-3-tridecyl-3,4-dihydroisocoumarin or 8-methoxy-3-tridecylisochroman-1-one), and its precursors, namely, methyl 2-methoxy-6-pentadecylbenzoate (37), methyl 2-methoxy-6-pentadecanoylbenzoate (38) and (E)-methyl 2-methoxy-6-(pentadec-1-enyl)benzoate (19) were synthesized from anacardic acid (12) as a starting material obtained from Cashew Nut Shell Liquid (CNSL) in an overall yield of 78%. The transformation of 12 to 39 involved protection of the reactive phenolic and carboxylic acid groups of compound 12 through methylation followed by hydrogenation so as to saturate the mono-, di- and tri-unsaturated C15 chains of anacardic acid (12). Subsequent benzylic oxidation and reduction of the keto functional group with concomitant dehydration of the alcohol led …
Cost Effective Strategy For The Synthesis Of Azo Dyes By Using Cashew Nut Shell Liquid (Cnsl), Mathias Yohana, Monica M. Ndoile, Quintino A. Mgani
Cost Effective Strategy For The Synthesis Of Azo Dyes By Using Cashew Nut Shell Liquid (Cnsl), Mathias Yohana, Monica M. Ndoile, Quintino A. Mgani
Tanzania Journal of Science
The synthesis and dyeing properties of two types of azo dyes are reported in this paper. The two types of dyes were obtained from coupling of amino cardanol with unsaturated anacardic acid [ACUSA (Aminocardanol unsaturated anacardic acid)] and saturated anacardic acid [ACSA (Aminocardanol saturated anacardic acid)] separately. Both, anacardic acid and aminocardanol were obtained from CNSL as their source material. ACSA dyes were solid and dark brown while ACUSA were gelatinous and dark red. The performance of both ACUSA and ACSA dyes was moderate on textile fabrics with varying cotton content. The dyeing efficiency of the ACUSA was better than …
Levels Of Heavy Metals In Drinking Water, Cosmetics And Fruit Juices From Selected Areas In Dar Es Salaam, Tanzania, John Am Mahugija
Levels Of Heavy Metals In Drinking Water, Cosmetics And Fruit Juices From Selected Areas In Dar Es Salaam, Tanzania, John Am Mahugija
Tanzania Journal of Science
Heavy metals were determined in samples of drinking water, cosmetics (nail polish, lip glosses and hair dye) and fresh fruit juices in Dar es Salaam. The samples were analyzed using Atomic Absorption Spectrometry (AAS) after digestion with concentrated acids, filtration and dilution. Lead, zinc and iron were detected in the water samples and the concentration ranges were below detection limit (BDL) to 0.114, 0.01 to 1.47 and 0.027 to 0.39 mg/L, respectively, whereas cadmium was not detected. The concentrations of lead in 70.83% of the samples exceeded the WHO permissible limit, implying that the water in most of the areas …
Status Of Selected Heavy Metals Dispersion From Top Soil In And Around Automobile Workshop Areas In Zanzibar Municipality, Tanzania, John Am Mahugija, Hawa M Sheikh
Status Of Selected Heavy Metals Dispersion From Top Soil In And Around Automobile Workshop Areas In Zanzibar Municipality, Tanzania, John Am Mahugija, Hawa M Sheikh
Tanzania Journal of Science
The distributions of selected heavy metals in top soil in areas with and without automobile workshops in Zanzibar municipality were investigated. Sampling was done during dry and rainy seasons. The samples were digested with aqua regia (HCl and HNO3, 3:1) and analysed by Atomic Absorption Spectrophotometry. The concentrations of zinc, copper and lead in the samples ranged 0.27–419.2, 0.10–167 and 0.02–271 mg/kg dry weight, respectively. The concentrations were higher in areas with automobile workshops than those without. The concentrations of the heavy metals were highest at point sources and decreased with increase in distance during the dry season. The concentrations …
Total Electron Content Derived From Global Positioning System During Solar Maximum Of 2012-2013 Over The Eastern Part Of The African Sector, Emmanuel D Sulungu, Christian Bs Uiso, Patrick Sibanda
Total Electron Content Derived From Global Positioning System During Solar Maximum Of 2012-2013 Over The Eastern Part Of The African Sector, Emmanuel D Sulungu, Christian Bs Uiso, Patrick Sibanda
Tanzania Journal of Science
This work presents results of diurnal, seasonal and latitudinal variations of vertical Total Electron Content (TECv) derived from GPS receivers at four locations, [Dodoma (6.19oS, 35.75oE), Mzuzu (11.43oS, 34.01oE), Zomba (15.38oS, 35.33oE) and Tete (16.15oS, 33.58oE)] during the solar maximum period of 2012 – 2013. The receivers are located directly below the EIA and at approximately the same longitude, ~ (33 – 3 oE) within the eastern part of the African sector. Diurnal and latitudinal variations of TECv are presented for an average of the five (5) quietest days of each of the four seasons: March equinox, June solstice, September …
Preliminary Sedimentology And Stratigraphy Of The Enigmatic Middle Lake Beds Succession (Pleistocene?) In The Rukwa Rift Basin, Tanzania, Cassy Mtelela
Tanzania Journal of Science
This paper presents sedimentology and stratigraphic overview of a series of previously unrecognized lithostratigraphic unit in the Rukwa Rift Basin, Tanzania. Based on the cross-cutting relationship and pilot detrital zircon geochronology, these isolated, enigmatic strata are herein informally termed the middle Lake Beds (mLB). Facies analysis reveals that the mLB units were deposited within a complex array of depositional environments, ranging from alluvial to fluvial channels, floodplains and shallow lakes. The mLB are characterised herein as isolated outcrop exposures with uncertain age relationships, but which can be divided into five distinctive lithostratigraphic units herein identified as informal members (A-E). These …
Heavy Metals And Cyanide Distribution In The Villages Surrounding Buzwagi Gold Mine In Tanzania, Edwin Sifuel Gomezulu, Agnes Mwakaje, Jamidu, H.Y. Katima
Heavy Metals And Cyanide Distribution In The Villages Surrounding Buzwagi Gold Mine In Tanzania, Edwin Sifuel Gomezulu, Agnes Mwakaje, Jamidu, H.Y. Katima
Tanzania Journal of Science
The study aimed at assessing the levels of heavy metals and cyanide in water and sediments in villages surrounding Buzwagi gold mine, both during wet and dry seasons. A total of 56 samples of water (28 from each season) and 44 samples of sediments (22 from each season) were collected from the wells in the area and were analyzed for total cyanide and heavy metals. The total cyanide was analyzed spectrophotometrically whilst the heavy metals were analyzed by an Inductively Coupled Plasma (ICP). The Pb and Fe levels in water were found to exceed 10 µg/L and 2000 µg/L respectively, …
Effect Of Storage Time And Temperature On Germination Ability Of Escoecaria Bussei, F Genes, Agnes Ms Nyomora
Effect Of Storage Time And Temperature On Germination Ability Of Escoecaria Bussei, F Genes, Agnes Ms Nyomora
Tanzania Journal of Science
This study was conducted in Botany Department Nursery to evaluate the effect of storage time and temperature on germinability of Excoecaria bussei. The orthodox seeds, collected from Dodoma and Singida regions were germinated monthly from September 2013 through June 2014. Each time, seeds were soaked in water for 6 hours to soften then sown in sterile potting media. A Split-Split plot was used to compare temperature [(15°C) and (30°C)] as main plots, populations (Maktupa, Kisalu and Ilola) as Sub plots and storage time (September 2013 through June 2014) as Sub-Sub-plots on percentage seed germination. ANOVA revealed average germination percentages of …
Optimization Of Biogas Production Process In Solid State Digesters In Semiarid Areas Of Northern Tanzania, Debora J Mahushiab, Alfred Nn Muzukaa, Revocatus L Machunda
Optimization Of Biogas Production Process In Solid State Digesters In Semiarid Areas Of Northern Tanzania, Debora J Mahushiab, Alfred Nn Muzukaa, Revocatus L Machunda
Tanzania Journal of Science
Solid state digestion process has received much attention due to its low water requirements, making it preferred in semi-arid areas as well. In this study, the performance of the household solid state digesters was evaluated through monitoring of the feedstock mixing ratios and using the digester gas pressure as a measure of performance. Additionally, a batch study to verify the appropriate and optimal mixing ratio of feedstocks was also done. The mixing ratios of cow dung to water were 2:1, 3:1 and 4:1. Total solids determined were 120, 150 and 170 mg/g for the ratios 2:1, 3:1 and 4:1, respectively. …
Structural Classification Using Aeromagnetic Data And Pseudogravity Transforms: A Case Study Of Pategi Area Of Bida Basin, Nigeria, Ayodele K Olawuyi, Halima M Amir, Mkabwa Lk Manoko
Structural Classification Using Aeromagnetic Data And Pseudogravity Transforms: A Case Study Of Pategi Area Of Bida Basin, Nigeria, Ayodele K Olawuyi, Halima M Amir, Mkabwa Lk Manoko
Tanzania Journal of Science
The structural classification with 3D Euler deconvolution method in the Pategi area, a transition environment between the Basement complex rocks of the southwestern Nigeria and the Sedimentary rocks of the Nupe Basin was carried out. It was aimed at identification of the structural features responsible for the hydrogeology and mineralization potentials of the area. This work involves the qualitative and quantitative analysis of aeromagnetic data and pseudogravity transforms using Oasis MontajTM. The 3-D Euler deconvolution of the acquired aeromagnetic data and pseudogravity transforms using Oasis montajTM software and the geologic information on this area was employed in the structural classification …
Speciation Of Lead, Chromium, Cadmium, Copper And Zinc In Sediments And Plants Along Msimbazi River In Dar Es Salaam, Tanzania, Faustin N Ngassapa, Othman C Othman, David Mihayo, Kessy F Kilulya
Speciation Of Lead, Chromium, Cadmium, Copper And Zinc In Sediments And Plants Along Msimbazi River In Dar Es Salaam, Tanzania, Faustin N Ngassapa, Othman C Othman, David Mihayo, Kessy F Kilulya
Tanzania Journal of Science
The speciation of lead, chromium, cadmium, copper and zinc in sediments and plants (pumpkin) along Msimbazi River in Dar es Salaam were determined using Atomic Absorption Spectrophotometry. Results in sediments indicated that the heavy metal contents (mg/kg) in the form of total trace metals ranged from 50.34 to 161.63 for Pb, 68.38 to 501.85 for Zn, 18.43 to 66.61 for Cu, 20.93 to 76.46 for Cr and BDL to 0.23 for Cd. The contents (mg/kg) in the form of metals bound to organic matter ranged from 18.24 to 46.58 for Pb, 27.64 to 228.62 for Zn, 3.55 to 16.76 for …
Seasonal Variation And Nutrient Levels Influence Phenolic Contents In Seagrass Thalassia Hemprichii Along Dar Es Salaam Coast, Asukisye Kajela, Esther F Mvungi
Seasonal Variation And Nutrient Levels Influence Phenolic Contents In Seagrass Thalassia Hemprichii Along Dar Es Salaam Coast, Asukisye Kajela, Esther F Mvungi
Tanzania Journal of Science
Seasonal variation in total phenolics in Thalassia hemprichii from four different sites with varied nutrient loading along Dar es Salaam coast was studied. Besides few studies existing on phenolics in seagrass species done to assess status of the seagrass meadows, there is paucity of information for seagrass species along the coast of Indian Ocean in Dar es Salaam. In this study, Thalassia hemprichii shoots were collected from four different sites having different levels of anthropogenic pressure during dry and rainy seasons. The total phenol contents of above and belowground parts of the seagrass were determined using Folin-Ciocalteu method. Results indicates …
Effects Of Magnetic Fields On An Unsteady Mixed Convective Boundary Layer Flow Of An Electrically Conducting Fluid With Temperature Dependent Properties, Raymond Kitengeso, Eunice Mureithi, Makungu James, John Mango
Effects Of Magnetic Fields On An Unsteady Mixed Convective Boundary Layer Flow Of An Electrically Conducting Fluid With Temperature Dependent Properties, Raymond Kitengeso, Eunice Mureithi, Makungu James, John Mango
Tanzania Journal of Science
A mixed convective boundary layer flow of an electrically conducting fluid with temperature dependent properties over an inclined plate is investigated. The magnetohydrodynamic boundary layer governing equations are derived by using Boussinesq and boundary layer approximations. The equations are transformed to similarity form using a similarity transformation variable and the resulting boundary value problem is solved numerically. The effects of magnetic fields, unsteadiness, mixed convection and variable fluid properties on velocity and temperature in the boundary layer are analysed. The effects of pertinent parameters on skin friction and heat transfer are also analysed
Assessment Of Radioactivity Levels In Coal And Coal Ash In Kiwira Coal Mine Using Gamma-Ray Spectrometry, Ismael N Makundi, Mungubariki M Nyaki, Najat K Mohammed
Assessment Of Radioactivity Levels In Coal And Coal Ash In Kiwira Coal Mine Using Gamma-Ray Spectrometry, Ismael N Makundi, Mungubariki M Nyaki, Najat K Mohammed
Tanzania Journal of Science
This study aimed to assess the radioactivity levels and associated dose rates from the naturally occurring radionuclides 226Ra, 232Th and 40K in coal and coal ashes at Kiwira coal mine. The radioactivity of 40 representative coal, fly ash samples were measured using gamma spectroscopy of the Tanzania Atomic Energy Commission (TAEC) in Arusha, Tanzania. The activity concentrations of 226Ra, 232Th and 40K in coal and coal ashes from Kiwira were higher by several orders of magnitude than their worldwide average values. The calculated radium equivalent activity, the air absorbed dose rate, external hazard index and the average annual effective dose …
Fluoride Occurrence In Domestic Water Supply Sources In Tanzania: A Case Of Meru District Arusha Region, Godfrey Mbabaye, Rwaichi Minja, Felix Mtalo, Isack , Legonda, Godfrey Mkongo
Fluoride Occurrence In Domestic Water Supply Sources In Tanzania: A Case Of Meru District Arusha Region, Godfrey Mbabaye, Rwaichi Minja, Felix Mtalo, Isack , Legonda, Godfrey Mkongo
Tanzania Journal of Science
Surface and ground water are the major sources of water supply in Meru district. Most of the people in Meru rural areas depend on surface water in rivers and ground water shallow and deep wells and springs for house hold activities. The presence of fluoride in high concentrations in drinking water or cooking water causes severe health problems to the people. Distribution of fluoride concentrations in Meru district domestic water sources was studied by referencing the location of water sources using Extrex 20 garmin hand held GPS instrument. Fluoride concentrations were measured using Metrohm Ag/AgCl reference electrode connected to a …
Through-The-Wall Radar Imaging With Compressive Sensing; Theory, Practice And Future Trends-A Review, Abdi Abdalla
Through-The-Wall Radar Imaging With Compressive Sensing; Theory, Practice And Future Trends-A Review, Abdi Abdalla
Tanzania Journal of Science
Through-the-Wall Radar Imaging (TWRI) is anemerging technology which enables us to detect behind the wall targets using electromagnetic signals. TWRI has received considerable attention recently due to its diverse applications. This paper presents fundamentals, mathematical foundations and emerging applications of TWRI with special emphasis on Compressive Sensing (CS) and sparse image reconstruction.Multipath propagation stemming from the surrounding walls and nearby targets are among the impinging challenges.Multipath components produce replicas of the genuine target, ghosts, during image reconstruction which may significantly increase the probability of false alarm. The resulting ghost not only creates confusion with genuine targets but may deteriorate the …
Assessment Of Water Quality Variation In Rivers Through Comparative Index Technique And Its Reliability For Decision Making, Aldo Kitalika, Revocatus Machunda, Hans Komakech, Karoli N Njau
Assessment Of Water Quality Variation In Rivers Through Comparative Index Technique And Its Reliability For Decision Making, Aldo Kitalika, Revocatus Machunda, Hans Komakech, Karoli N Njau
Tanzania Journal of Science
The National Sanitation Foundation (NSF) and Weighed Arithmetic Index (WAI) methods for water quality index (WQI) have been studied to evaluate their reliability in water quality assessment in rivers. Water samples were collected in various GPS predetermined points in Temi, Nduruma, Tengeru and Maji ya Chai rivers-Tanzania during wet and dry seasons and were analyzed for several water quality parameters using standard methods as per APHA. Medium to excellent water qualities were observed for pristine environment in three rivers except Maji ya Chai under NSF and WIA methods, respectively. Excellent water quality was observed in the pristine environment of Temi …
Prediction Of Rainfall In The Southern Highlands Of Tanzania, Pasvolo Mwinuka, Christian Uiso
Prediction Of Rainfall In The Southern Highlands Of Tanzania, Pasvolo Mwinuka, Christian Uiso
Tanzania Journal of Science
Previous studies on the variability of March to May (MAM) and October to December (OND) rainfall in East Africa have mainly covered the whole region without considering the local climate zones such as the Southern Highlands of Tanzania. Results from the regional studies have shown that the Indian Ocean Dipole (IOD) and Outgoing Longwave Radiation (OLR) have strong association with OND rainfall and weak one with MAM rainfall in East Africa. The present study was aimed at determining the potential predictors for the MAM and OND rainfall by considering IOD, El Ni o Southern Oscillation (ENSO), Quasi-biennial Oscillation (QBOu30 and …