Open Access. Powered by Scholars. Published by Universities.®

Digital Commons Network™

Open Access. Powered by Scholars. Published by Universities.®

2021

Discipline
Institution
Keyword
Publication
Publication Type
File Type

Articles 121 - 150 of 42330

Full-Text Articles in Entire DC Network

Game Edukasi Pembagian Bilangan Berbasis Android Untuk Siswa Kelas 2 Sekolah Dasar, Dyah Triwahyuningtyas, Dela Sari Novaria, Cicilia Ika Rahayu Nita Dec 2021

Game Edukasi Pembagian Bilangan Berbasis Android Untuk Siswa Kelas 2 Sekolah Dasar, Dyah Triwahyuningtyas, Dela Sari Novaria, Cicilia Ika Rahayu Nita

Jurnal Pendidikan: Teori, Penelitian, dan Pengembangan

The background of this research is the unavailability of fun and non-boring media based on IT. To foster interest and motivation with the concept of playing while learning through an Android-based number division educational game. The research aims at educational games based on Android class II in elementary schools are feasible, practical, and effective. The development method using the 4D model consists of four stages, including the define stage, the design stage, the developing stage, and the dissemination stage. The analysis technique is thorough qualitative and quantitative descriptive data analysis. The results of the study stated that the Android-based number …

Go to article

Outlier And Homogeneity Analysis Of Extreme Rainfall Series In Kano, Nigeria, Abdulrasheed Mohammed, Salisu Dan’Azumi, Abubakar Ahmed Modibbo Dec 2021

Outlier And Homogeneity Analysis Of Extreme Rainfall Series In Kano, Nigeria, Abdulrasheed Mohammed, Salisu Dan’Azumi, Abubakar Ahmed Modibbo

Platform: A Journal of Engineering (PAJE)

Data preparation is one of the most important steps in the field of hydrology since the results of any research depend on whether the input data were reliable and rightly collected or not. Reliability and quality of long-term rainfall data are required before carrying out any study in hydrology. For this reason, outlier identifcation techniques and homogeneity tests have proved helpful. This study aimed at carrying out outliers and homogeneity analysis of extreme rainfall data series for the Kano rainfall gauging station. XLSTAT, 2019 was used to identify outliers through Grubb’s test for outliers/two-tailed test and Dixon test for outliers/two-tailed …

Go to article

Characterization Of The Ch Addition Product From Meta- And Ortho-Xylene + Ch Reaction And Direct Experimental Observation Of The Tetrabromine Cluster Br4 Using Synchrotron Photoionization Mass Spectrometry, Rory R. Mcclish Dec 2021

Characterization Of The Ch Addition Product From Meta- And Ortho-Xylene + Ch Reaction And Direct Experimental Observation Of The Tetrabromine Cluster Br4 Using Synchrotron Photoionization Mass Spectrometry, Rory R. Mcclish

Master's Theses

This thesis is centered on the use of a unique gas-phase spectroscopy technique to characterize products and elucidate reaction mechanisms. Experiments were carried out at the Chemical Dynamics Beamline 9.0.2 of the Advanced Light Source located at the Lawrence Berkeley National Laboratory in Berkeley, CA. Computational work was performed on the scientific supercomputer at USF to supplement experimental findings. Chapter 1 contextualizes the work spurred in response to the deleterious interactions of anthropogenic emissions on Earth’s climate. Chapter 2 describes the theoretical manipulations foundational to the experimental design and interpretation. Chapter 3 delves into the physical details of the experimental …

Go to article

Social Media Usage And Transitioning Into Online Classes During Covid-19- A Survey Of Undergraduate Students In Georgia, United States, Sylvia Ofori, Janet Choongo, Mario Kekop, Gulzar H. Shah, Haresh Rochani, Joseph Telfair Dec 2021

Social Media Usage And Transitioning Into Online Classes During Covid-19- A Survey Of Undergraduate Students In Georgia, United States, Sylvia Ofori, Janet Choongo, Mario Kekop, Gulzar H. Shah, Haresh Rochani, Joseph Telfair

Health Policy & Community Health: Faculty Publications

Previous studies on the use of social media (SM) during the COVID-19 pandemic have focused on the use in sustaining academic communication. This study aimed to assess the association between SM and the ease of transitioning to online classes during the COVID-19 pandemic using survey data from 872 undergraduate students. The findings showed that Snapchat and Instagram were the most preferred social media sites among participants. Compared to students who use SM for < 2 hours a day, use for > 5 hours (AOR= 2.44; 95% CI, 1.13 – 5.25) or 3 to 5 hours a day (AOR = 2.01, 95% CI 1.06-3.81) increased the odds of easily …

Go to article

Integral Method For Assessing The Sustainable Competitiveness Of Service Enterprises Selling Food Products, Niyozov Jamoliddin Safarivich Dec 2021

Integral Method For Assessing The Sustainable Competitiveness Of Service Enterprises Selling Food Products, Niyozov Jamoliddin Safarivich

Journal of Environmental Science and Sustainable Development

After the transition to the market economy, the consumer market of the Republic of Tajikistan faced different problems of the competitiveness of retail trade enterprises and the quality of services. In the result of our previous research about retail competitiveness, we defined some of the disadvantages in this sphere, expressed in the candidate dissertation on theme “Improving the retail enterprise competitiveness management system”. Problems regarding to the competitiveness of enterprises and the provision of quality services to consumers influenced the research an integral assessment of competitiveness. So, just only with by an integral assessment of competitiveness, economically sound solutions are …

Go to article

Full Issue, Iajbs Ateneo De Manila University Dec 2021

Full Issue, Iajbs Ateneo De Manila University

Journal of Management for Global Sustainability

No abstract provided.

Go to article

Gender Influence On Student Teachers' Perceptions Of The Constructs Of Technolog-Ical Pedagogical Content Knowledge (Tpack) In Nigerian Universities, Mudasiru Olalere Yusuf Dec 2021

Gender Influence On Student Teachers' Perceptions Of The Constructs Of Technolog-Ical Pedagogical Content Knowledge (Tpack) In Nigerian Universities, Mudasiru Olalere Yusuf

Journal of Educational and Psychological Studies

Abstract:This study investigated whether gender influences the perceptions of TPACK constructs among male and female student teachers in public universities in north-central Nigeria. The study adopted the cross-sectional survey design carried out using the TPACK questionnaire across the study's sample. Sample selection for the study was based on a multi-stage sampling technique. Accordingly, a questionnaire was distributed to a sample of 529 male and female student teachers in their final year enrolled in three universities in Kwara State, Nigeria. They responded to the study tool that was accessed after the validity and reliability of the tool had been verified using …

Go to article

Modelling The Impact Of Undetected Cases On The Transmission Dynamics Of Covid-19, Herieth Rwezaura Dec 2021

Modelling The Impact Of Undetected Cases On The Transmission Dynamics Of Covid-19, Herieth Rwezaura

Tanzania Journal of Science

The spread of COVID-19 globally has caused negative impacts to the public, making understanding the dynamics of transmission a necessity. Essential factors such as undetected cases, asymptomatic cases, and several non-pharmaceutical interventions have played significant roles in the spreading mechanism of COVID-19 in the human population. It is imperative to understand the significance of these factors in order to determine whether COVID-19 will be eradicated or will continue to persist in the population. A mathematical model is formulated to investigate the impacts of vaccination and several non-pharmaceutical interventions on the dynamics of a COVID-19 accounting for asymptomatic cases, detected (identified) …

Go to article

Optical And Chemical Properties Of Fragaria Ananassa And Galena: Potential Photosensitizers In A Natural Dye-Sensitized Solar Cell, Ibukun S Akinsola, Aderemi B Alabi, Coppede Nicola Dec 2021

Optical And Chemical Properties Of Fragaria Ananassa And Galena: Potential Photosensitizers In A Natural Dye-Sensitized Solar Cell, Ibukun S Akinsola, Aderemi B Alabi, Coppede Nicola

Tanzania Journal of Science

Dye is one of the major components for high power conversion efficiency in a dye-sensitized solar cell. There are challenges natural dyes encounter, especially with quick degradation of the dye molecules. This work considered mineral dye in comparison with plant dye to address the challenge of degradation of natural plant dyes. The optical properties and functional groups of the two natural dyes were studied in this work. The absorption spectra, the optical band gaps and the absorption coefficients of the dyes were reported and found to be suitable for use as photosensitizers in a dye-sensitized solar cell (DSSC), as they …

Go to article

Rural Electrification Using Iliceto Shield Wire Scheme In Developing Countries: Tanzania Case Study, Heavenlight M Munisi, Santos Kihwele Dec 2021

Rural Electrification Using Iliceto Shield Wire Scheme In Developing Countries: Tanzania Case Study, Heavenlight M Munisi, Santos Kihwele

Tanzania Journal of Science

Rural electrification rate in Tanzania is still very low despite the efforts made by the Rural Energy Agency (REA) in Tanzania. Rural electrification using medium voltage (MV) method has two major obstacles. First obstacle is high cost associated with the cost of extending the grid electricity to rural areas. Second obstacle is remoteness of the villages, which leads to high power loss during transmission. In lieu of economic extension of rural electrification areas, this paper proposes a low cost solution of Iliceto Shield Wire Scheme (ISWS). This technique involves insulating shield wires (SW) from high voltage (132-400 kV) transmission line …

Go to article

Determination Of Cramer-Rao Lower Bound (Crlb) And Minimum Variance Unbiased Estimator Of A Dc Signal In Awgn Using Laplace Transform, Abdi T. Abdalla Dec 2021

Determination Of Cramer-Rao Lower Bound (Crlb) And Minimum Variance Unbiased Estimator Of A Dc Signal In Awgn Using Laplace Transform, Abdi T. Abdalla

Tanzania Journal of Science

This paper presents an alternative approach for the determination of Cramer-Rao Lower Bound (CRLB) and Minimum Variance Unbiased Estimator (MVUE) using Laplace transformation. In this work, a DC signal in Additive White Gaussian Noise (AWGN) was considered. During the investigation, a number of experiments were conducted to analyze different possible outputs under different conditions, and then the patterns of the outcomes were studied. Finally closed-form expressions for the CRLB and MVUE were deduced employing the Laplace transformation. The resulting expressions showed that the proposed method has almost the same number of steps as the existing method. However, the latter requires …

Go to article

Effects Of Ripeness And Blending Speed On The Extraction Yield And Physical Chemical Properties Of Low Viscosity Banana Juice, Oscar Kibazohi, Victor V Matabura Dec 2021

Effects Of Ripeness And Blending Speed On The Extraction Yield And Physical Chemical Properties Of Low Viscosity Banana Juice, Oscar Kibazohi, Victor V Matabura

Tanzania Journal of Science

Low viscosity banana juice can be extracted from banana by blending and pressing the resulted semi-solid pulp to separate the juice. This juice extraction technology is relatively new and further studies to understand key parameters for juice release is vital for scaling up production and commercialisation. This study, investigated the influence of blending speed and ripeness stage on banana juice yield using two banana cultivars; the East African highland banana (Mbile) and the exotic banana (Pisang awak). Types of sugars and organic acids in the juice were analysed using an HPLC. Changes with ripening of fruit firmness, juice pH and …

Go to article

Critical Analysis Of Material Consumption And Cost Reduction Techniques For The Apparel Cutting Processes, Ismael Taifa, Ibrahim Twaha, Mboka A Mwakibambo Dec 2021

Critical Analysis Of Material Consumption And Cost Reduction Techniques For The Apparel Cutting Processes, Ismael Taifa, Ibrahim Twaha, Mboka A Mwakibambo

Tanzania Journal of Science

Revenues generation in the garment industry is synonymous with material consumption. This study thus analysed material consumption and cost reduction techniques in the Tanzanian garment industry. The research employed quantitative (experimentation) and qualitative approaches (document review and observation technique) in the apparel cutting processes. Experimental results of material consumption from ten tests averaged efficiency of 78.67%, the wasted pieces (19.2%), and unnoticed waste (2.03%). Essential considerations to reduce material waste include: digitalising the fabric cutting processes; providing workers training; deploying appropriate practices in the cutting room (e.g. pattern engineering and pattern accuracy); considering the quality of the procured fabric and …

Go to article

Environmental Noise Pollution And Its Impacts On The Hearing Ability Of Men And Women In Ilorin, Kwara State, Nigeria, Afolabi M. Tunde, Salamat Abdulquadri Dec 2021

Environmental Noise Pollution And Its Impacts On The Hearing Ability Of Men And Women In Ilorin, Kwara State, Nigeria, Afolabi M. Tunde, Salamat Abdulquadri

Tanzania Journal of Science

Noise is an environmental disturbance that has harmful effects on the physiological and psychological lives of human beings and animals. This work examined the perceived health implications associated with noise pollution on both genders in Ilorin, Nigeria. It specifically identified the major sources of noise pollution, assessed noise pollution levels in the selected areas and determined the differences in the impacts of noise pollution on the health of both genders in Ilorin. A total of 384 respondents were sampled. Sound Level Meter (SLM) was used to ascertain the levels of noise in the study areas. Descriptive statistics and ANOVA were …

Go to article

Paleodepositional Environment And Sequence Stratigraphy Of Miocene Sediments In Well Tn-1, Coastal Swamp Depobelt, Niger Delta Basin, Nigeria, Jerry Osokpor, Efetobore G Maju-Oyovwikowhe Dec 2021

Paleodepositional Environment And Sequence Stratigraphy Of Miocene Sediments In Well Tn-1, Coastal Swamp Depobelt, Niger Delta Basin, Nigeria, Jerry Osokpor, Efetobore G Maju-Oyovwikowhe

Tanzania Journal of Science

This research focused on the interpretation of paleodepositional environment and development of a sequence stratigraphic framework for the well TN-1 section, located in the coastal swamp depositional belt of the Niger Delta Basin. Integration of interpreted litho- and biofacies data sets that facilitated the interpretation of the paleodepositional environment enabled the erection of a sequence-stratigraphic framework. Three lithotypes (sand, clay, and shale) distributed within fourteen facies variants were integrated with palynomorph components to delineate five paleodepositional cycles ranging from distal delta plain to bathyal. Eight systems tracts (closely related to depositional cycles, but transcended depositional boundaries in some intervals) that …

Go to article

Temperature Effects On The Corrosion Inhibition Of Mild Steel In Sulfuric Acid Solution By Acacia Senegal Gum With Halide Ions, Jovine Emmanuel, Joseph Buchweishaija Dec 2021

Temperature Effects On The Corrosion Inhibition Of Mild Steel In Sulfuric Acid Solution By Acacia Senegal Gum With Halide Ions, Jovine Emmanuel, Joseph Buchweishaija

Tanzania Journal of Science

The effects of temperature on the inhibitive effect of naturally occurring Acacia senegal gum exudate on the corrosion of mild steel in sulfuric acid was studied between 35 and 70 °C using electrochemical impedance spectroscopy and potentiodynamic polarization methods. Findings showed that Acacia senegal gum exudate decreases the corrosion rate of mild steel. The inhibition efficiency declined with raising temperature above 35 °C. The increase in the corrosion rate with increasing temperature was observed for both uninhibited and inhibited systems. Addition of halide ions to the Acacia senegal gum exudate solution enhanced the corrosion inhibition efficiency because of synergistic effects, …

Go to article

Physico-Chemical Properties Of Mechanically Extracted Banana Juice At Different Ripening Stages, Mathayo G Mathias, Lilian D Kaale, Oscar Kibazohi Dec 2021

Physico-Chemical Properties Of Mechanically Extracted Banana Juice At Different Ripening Stages, Mathayo G Mathias, Lilian D Kaale, Oscar Kibazohi

Tanzania Journal of Science

This paper presents the findings of a study on physico-chemical properties of low viscosity banana juice from five banana cultivars: Pisang Awak (PSA) an ABB genome, Yangambi km5 (YKM5) an AAA genome and cultivars from AAA-EA genome, namely Mbilabile, Ndeshi and Mlonga. Low viscosity banana juice was extracted using improved mechanical method at five ripening stages. The physico-chemical properties significantly varied according to cultivars and ripening stages (p < 0.05). Yields, total soluble solids (TSS), titratable acidity (TA) and pH were in the range of 19.50–74.03%, 7.33–27.64 ºBrix, 0.37–0.76% malic acid equivalent and 4.09–4.70, respectively. Yields decreased in the order of Mbilabile > Ndeshi > Mlonga > YKM5 > PSA whereas the total soluble solids increased as follows Mlonga < Mbilabile < Ndeshi < YKM5 < PSA. Furthermore, ashes and mineral contents decreased with ripening stages whereas the low viscosity banana juice was rich in potassium and magnesium. Finally, the study recommends stage 5 of the ripeness as ideal for producing low viscosity banana juice. Keywords: Mechanical extraction, Banana cultivar, Ripening stage, Tannin, Banana juice.

Go to article

Analysis Of The Current And Future Land Use/Land Cover Changes In Peri-Urban Areas Of Dar Es Salaam City, Tanzania Using Remote Sensing And Gis Techniques, Erick T Mnyali, Silvia F Materu Dec 2021

Analysis Of The Current And Future Land Use/Land Cover Changes In Peri-Urban Areas Of Dar Es Salaam City, Tanzania Using Remote Sensing And Gis Techniques, Erick T Mnyali, Silvia F Materu

Tanzania Journal of Science

A rapid increase in population and urban development has direct impacts on the natural environment of peri-urban areas of big cities, especially in the developing countries. This study examined land use and land cover changes (LULCC) of peri-urban areas of Kinondoni Municipality in Dar es Salaam city for the period between 1999 and 2019 and predicted future changes by 2039. The specific objectives were to; (i) map the spatial-temporal land use and cover changes (ii) analyze settlements (built-up areas) patterns and factors influencing their changes (iii) predict changes that might happen for the next two decades. LULCC for 1999 to …

Go to article

Atmospheric Instability Conditions During Rainy Seasons Over Tanzania, Pasvolo J Mwinuka, Christian Bs Uiso, Ladslaus B Chang’A, Mwingereza J Kumwenda Dec 2021

Atmospheric Instability Conditions During Rainy Seasons Over Tanzania, Pasvolo J Mwinuka, Christian Bs Uiso, Ladslaus B Chang’A, Mwingereza J Kumwenda

Tanzania Journal of Science

The amount of rainfall and its distribution in time and space is dependent on the atmospheric instability conditions, and on its moisture content. The aim of this study was to determine the atmospheric instability conditions during January to March (JFM), February to April (FMA), March to May (MAM), and October to December (OND) rainy seasons over local climate zones in Tanzania. Zone area average seasonal Convective Available Potential Energy (CAPE), Convective Inhibition (CIN), Precipitable Water (PW) and Lifted index (Li) were calculated and analyzed. Results showed Li < 0 in JFM and FMA over whole Tanzania. During MAM and OND, Li < 0 over the Lake Zone, Western Highlands Zone and Central Zone only. CAPE ranged from 793 J/kg to 1183 J/kg during JFM, and 700 J/kg to 1080 J/kg during FMA. During MAM, CAPE ranged from 170 J/kg to 921 J/kg and from 173 J/kg to 833 J/kg during OND. Results also showed CAPE > 1000 J/kg over the Lake Zone, Western Highlands Zone, Island Zone, and Central …

Go to article

Analogue Sandbox Scaled Modelling Of Oblique And Orthogonal Extension Rifting In Rukwa Rift Basin, Tanzania, Tonny Ojok, John Bk Duot, Majorine Namaganda, Nasra Sadiki, Michael Msabi Dec 2021

Analogue Sandbox Scaled Modelling Of Oblique And Orthogonal Extension Rifting In Rukwa Rift Basin, Tanzania, Tonny Ojok, John Bk Duot, Majorine Namaganda, Nasra Sadiki, Michael Msabi

Tanzania Journal of Science

Fault evolution in oblique and orthogonal rift systems in the brittle upper crust of the Rukwa rift basin was simulated using scaled sandbox modelling by varying the angle between the rift axis and the extension direction, α, through 45° and 90°, over a 10 cm displacement. The 45° oblique model exhibits a half-graben architecture bounded by a planar fault, intra-rift faults and a conjugate fault in some vertical sections. The map view of the model’s basin trends in the NW-SE direction, and is comparable with the Rukwa rift basin orientation. The 90° oblique model forms a basin structure which is …

Go to article

Design And Performance Analysis Of Composite Airfoil Wind Turbine Blade, Hegespo H Mwanyika, Yusufu Ac Jande, Thomas Kivevele Dec 2021

Design And Performance Analysis Of Composite Airfoil Wind Turbine Blade, Hegespo H Mwanyika, Yusufu Ac Jande, Thomas Kivevele

Tanzania Journal of Science

Small horizontal axis wind turbine rotors with composite airfoil rotor blades were designed and investigated in the present study in order to improve its performance in low wind speed and low Reynolds number (Re) conditions for standalone system. The geometrical and aerodynamic nature of a single airfoil small horizontal axis wind turbine blade curtails efficient energy harnessing of the rotor blade. The use of composite airfoil rotor blade improves energy production but imposes uncertainty in determining an optimal design angle of attack and the off design aerodynamic behaviour of the rotor. This research investigated the effects of two airfoils used …

Go to article

Optimal Design Of Hybrid Renewable Energy For Tanzania Rural Communities, Ester T Marcel, Joseph Mutale, Aviti T Mushi Dec 2021

Optimal Design Of Hybrid Renewable Energy For Tanzania Rural Communities, Ester T Marcel, Joseph Mutale, Aviti T Mushi

Tanzania Journal of Science

Rural communities in developing countries lack access to electricity due to high costs of grid extension. This paper proposes a hybrid system of renewable energy (HRES) as solution. The HRES consists of solar, wind, and battery energy storage (BES). The village called Ngw’amkanga in Shinyanga region of Tanzania, East Africa is selected as a case study. An iterative method to determine the size of wind and solar photovoltaic (PV) generation required assuming a project life of 25 years at minimum annualised cost of the system ( ) is proposed. The project life time is fixed on the life span of …

Go to article

Application Of Faulkenberry (2018) Bayes Factor To A Balanced Two Way Analysis Of Variance With Random Effects, Onyeike D. Egburonu, Omotayo A. Abidoye Dec 2021

Application Of Faulkenberry (2018) Bayes Factor To A Balanced Two Way Analysis Of Variance With Random Effects, Onyeike D. Egburonu, Omotayo A. Abidoye

Tanzania Journal of Science

The Analysis of Variance technique estimates variance components by comparing their mean squares to their expected values. Nevertheless, this method could give variance component estimates that are found outside the parameter space, i.e. negative estimates. In a bid to overcome this deficiency, alternate approaches are essential, and likelihood-based approaches have become common over time. Bayesian techniques have also been proposed and Bayes factors developed for examining various models. We applied the Bayes factor proposed by Faulkenberry (2018) to a Balanced Two Way ANOVA under three (3) cases, namely Case 1: the levels of the two factors are fixed; Case 2: …

Go to article

Smart Electric Meter Deployment In Tanzania: A Survey, Theresia B Maziku, Kwame S Ibwe, Abdi Abdalla, Ellen A Kalinga Dec 2021

Smart Electric Meter Deployment In Tanzania: A Survey, Theresia B Maziku, Kwame S Ibwe, Abdi Abdalla, Ellen A Kalinga

Tanzania Journal of Science

Using information and communication technologies (ICT) to make the electrical power network intelligent and smarter (smart grid) has been the focal point in transforming electrical power industry. The idea behind smart grid is to transform the Tanzanian power sector into a secure, adaptive, sustainable, and digitally enabled ecosystem that provides reliable and quality energy for all with active participation of stakeholders. Smart metering is a central segment in realizing smart grid. However, a big question is whether Tanzanian power stakeholders are ready for smart metering technology investments for household applications. Operation and maintenance of a smart metering solution is a …

Go to article

Improved Modified Ratio Estimation Of Population Mean Using Information On Size Of The Sample, Sikiru A Suleiman, Amos A Adewara Dec 2021

Improved Modified Ratio Estimation Of Population Mean Using Information On Size Of The Sample, Sikiru A Suleiman, Amos A Adewara

Tanzania Journal of Science

In sample surveys, auxiliary information is used for estimation to improve the efficiency of estimators. Increased precision can be obtained when the variable under study is highly correlated with auxiliary information. In this study, the sample size has been used as information for improved estimation of population mean of the main variable under study. A new modified generalized ratio type estimator of population mean has been proposed and the efficiency was examined using Murthy (1967) and Mukhopadhyay (2009) dataset. The large sample properties, the bias and the mean squared error of the newly proposed modified ratio estimator were obtained up …

Go to article

Adaptive Sliding Mode Contouring Control Design Based On Reference Adjustment And Uncertainty Compensation For Feed Drive Systems, Mathew Renny Msukwa, Santos Kihwele Dec 2021

Adaptive Sliding Mode Contouring Control Design Based On Reference Adjustment And Uncertainty Compensation For Feed Drive Systems, Mathew Renny Msukwa, Santos Kihwele

Tanzania Journal of Science

Industrial feed drive systems, particularly, ball-screw and lead-screw feed drives are among the dominating motion components in production and manufacturing industries. They operate around the clock at high speeds for coping with the rising production demands. Adversely, high-speed motions cause mechanical vibrations, high-energy consumption, and insufficient accuracy. Although there are many control strategies in the literature, such as sliding mode and model predictive controls, further research is necessary for precision enhancement and energy saving. This study focused on design of an adaptive sliding mode contouring control based on reference adjustment and uncertainty compensation for feed drive systems. A combined reference …

Go to article

Risk Factors Associated With Mother-To-Child Transmission Of Hiv In Dar Es Salaam, Tanzania, Felix Elias, Nyimvua Shaban, Edwin Rutalebwa Dec 2021

Risk Factors Associated With Mother-To-Child Transmission Of Hiv In Dar Es Salaam, Tanzania, Felix Elias, Nyimvua Shaban, Edwin Rutalebwa

Tanzania Journal of Science

Despite Tanzania's efforts and substantial progress in PMTCT, about 11% new infections were recorded among Tanzanian children in 2019 (UNAIDS 2020a). The objective of this study was to determine the rate of HIV transmission and to identify its risk factors among HIV exposed infants born to HIV-positive mothers in Dar es Salaam, Tanzania. A cross-sectional study was conducted using retrospective data collected from HIV-positive mothers and their exposed babies who were followed and registered in health facilities in four administrative districts (Ilala, Temeke, Kinondoni, and Ubungo) in Dar es Salaam between January 2016 and December 2019.  To identify risk factors …

Go to article

Application Of F-Waspas In The Ranking Of Crops For Agro-Processing: The Case Of Ikondo Ward In Njombe, Tanzania, Benito G Mng'ong'o, David Koloseni Dec 2021

Application Of F-Waspas In The Ranking Of Crops For Agro-Processing: The Case Of Ikondo Ward In Njombe, Tanzania, Benito G Mng'ong'o, David Koloseni

Tanzania Journal of Science

The purpose of this work was to develop and apply a Fuzzy Weighted Aggregated Sum Product Assessment (F-WASPAS) method in ranking selected crops for agro-processing at Ikondo Ward in Njombe Region, Tanzania. The fuzzy technique for order preferences by similarity to ideal solution (TOPSIS) was applied in determining the fuzzy importance weights of criteria, while the fuzzy WASPAS successfully ranked the crops, and maize was ranked the highest. Keywords:    F-WASPAS, Linguistic variables, Fuzzy aggregation, Agro-processing, Decision making, Multi-Criteria Decision Making.

Go to article

Biodiesel Generation From Palm Kernel Biomass Via An In-Situ Transesterification Approach, Chikaodili D Ikechukwu, Ikhazuagbe H Ifijen, Nyaknno U. Udokpoh Dec 2021

Biodiesel Generation From Palm Kernel Biomass Via An In-Situ Transesterification Approach, Chikaodili D Ikechukwu, Ikhazuagbe H Ifijen, Nyaknno U. Udokpoh

Tanzania Journal of Science

This study investigated an in-situ transesterification of palm kernel biomass at variable reaction times (4 h, 5 h and 6 h) and catalyst loading (2 wt%, 3 wt.% and 5 wt.%). The biodiesel yields were observed to vary with these parameters. GC-MS analysis showed high fatty acid methyl esters (FAMEs) contents for all the prepared biodiesel samples (C-18:1, C-14:0, C-16:0, and C-18:0). 2 wt.% catalyst loading and 4 h reaction time were observed to be the best reaction conditions from the experimented parameters that gave the best biodiesel yield at 300 rpm mixing intensity. The in-situ method recorded a higher …

Go to article

Mathematical Characterization Of Biological Control Of Cassava Pests Model, Yidiat O. Aderinto, Faith O. Ibiwoye, Michael O. Oke, Folashade M. Jimoh Dec 2021

Mathematical Characterization Of Biological Control Of Cassava Pests Model, Yidiat O. Aderinto, Faith O. Ibiwoye, Michael O. Oke, Folashade M. Jimoh

Tanzania Journal of Science

Pests are major constraints to the effective growth and development of every crop through their damage, and can be controlled effectively by the use of their natural enemies which is referred to as the biological pest control. In this study, the biological control model of cassava pests through optimal control theory was presented in order to minimize the population of the pests and stabilize the natural enemies population so as not to affect the crop negatively. A mathematical model was formulated via the Lotka-Volterra model, and the model was characterized. The optimality system was established, the equilibrium point with its …

Go to article

First Prev Next Last