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Evaluating performance of the improved hybrid passive and active mode solar dryers for processing Mangoes and Pineapples
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Doctor of Philosophy in Life Sciences of the Nelson Mandela African Institution of
Science and TechnologyFarmers in East Africa have no access to modern processing technologies because they are
costly and high-energy demanding to operate. As a result, they solely rely on the traditional
open sun drying (OSD) method, which is ineffective and causes further loss of the produce.
In response, a modified passive-mode hybrid solar dryer dubbed ‘Improved Solar Dryer
(ISD)’ unit was developed. A conventional active mode hybrid solar dryer nicknamed a
‘Solar Photovoltaic and Electric (SPE)’ dryer was fabricated. In this study, the drying
performance of the individual ISD and SPE dryers was evaluated and compared against that
of the OSD method. The effect of the individual ISD and SPE dryers on the nutritional
content and sensory quality of the solar-dried fruits, namely mangoes and pineapples, was
also assessed. The fruits were dried using the ISD and SPE dryers, and OSD methods while
following randomized complete block design experimental procedures. Results show that the
drying performance of the ISD and SPE dryers was better than that of the OSD method. The
SPE and ISD dryers took 10 and 18 hours to effectively dry the fruit products, respectively,
as opposed to the 30 hours taken by the OSD method. The mean daily ambient temperature
and relative humidity were 26.8oC and 26.7%, respectively. The mean drying air
temperatures achieved by the ISD and SPE dryers were 27.7 and 40.3oC, respectively. The
mean relative humidity achieved by the ISD and SPE dryers during the entire food drying
process were 25.8 and 24.6%, respectively. The mean solar thermal energy recorded for the
ISD dryer, SPE dryer, and OSD method were 4795, 5994, and 3595 W/m2
(Watts per square
meter), respectively. The results suggest that the SPE dryer exhibited better drying
performance than the ISD dryer. The results also confirm that the drying conditions attained
by both the SPE and ISD dryers were superior to that of the OSD method. Results confirm an
enhanced capacity and superior role of the ISD and SPE dryers in retaining both the sensory
quality and nutritional content. Therefore, the ISD and SPE dryers are recommended for
drying fruits
Assessing intensification options of common bean cultivation to improve food security on smallholder farms in the northern highlands of Tanzania
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of Philosophy in Life Sciences of the Nelson Mandela African Institution of
Science and TechnologyComplementarities of common bean (Phaseolus vulgaris L.) with non-legume food crops and
their significances to the agricultural systems are underexploited. Based on the description of
this study, eight options were assessed for the sustainable intensification of common bean
cultivation (through manipulations of intercropping and rotation) against the monocultures of
maize (Zea mays L.), and the improved and local varieties of common bean in the northern
highlands of Tanzania. The factors assessed were the cropping seasons/years (S) (2015 to
2017), agro-ecological zones (A) above sea level (lower 843 m, middle 1051 m, upper 1743
m), cropping systems (C) (sole, intercrop, rotation), and bean varieties (V) (improved
Lyamungu 90 and local Mkanamna) and their interactions. Results indicated that S, A, C, and
S×A, S×C, S×A×C were significant and bean grain yields increased in intercrops ranging
from 1.5 to 2.9 t ha-1 with land equivalent ratio (LER) of 1.58. Intercropping over five
cropping seasons indicated that with S×V grain yields increased from 0.2 to 3.5 t ha-1
in bean
and from 2.3 to 2.6 t ha-1
in maize with LERs of 1.48 and 1.55. In rotations, higher bean grain
yields were attributed to S (3.3 t ha-1
), C (3.4 t ha-1
), and V (2.7 t ha-1
) and for maize were in C
(2.9 t ha-1
) and S (2.6 t ha-1
). In conclusion, out of eight assessed options, this study found two
main useful options for improving food security on smallholder farms in the northern
highlands of Tanzania. The options were continuous cultivation of the improved and/or local
varieties of common bean in intercrops with the maize throughout two rainy seasons of the
year (long and short). Another option was cultivation of the improved and/or local varieties of
common bean intercropped with maize in the long rainy season and rotating of these
intercrops with the maize cultivated in the short rainy seasons. Importantly, the improved
bean variety Lyamungu 90 was heavier in weight, using the same number of seeds, than the
local bean variety Mkanamna, which provided additional factors to be considered to improve
income where weight is the acceptable standard in the market
Sanger sequence automatic analysis tool development
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Master’s in Information and Communication Science and Engineering of the Nelson
Mandela African Institution of Science and TechnologyThe Sanger sequencing technique still remains the cornerstone methods for the
Deoxyribonucleic acid (DNA) sequencing. This is due to its high accuracy in targeting smaller
genomic regions in a large number of samples, sequencing of variable regions and validating
results of other DNA sequencing platforms such as those from next-generation sequencing
studies. The analysis of Sanger sequence DNA data is computationally intensive requiring
efficient and high computational power software tools. The most preferred tools are the
proprietary licensed tools since they offer user-friendly interface and they offer more DNA
analysis functionalities. However, the affordability of the tools may be limited especially for
individual researchers or students due to their expensive licenses. Nevertheless, free and open source licensed tools are available and but are not user-friendly, have steep learning curve since
some lack graphical user interface, operating system platform dependent and have limited
functionalities. This study presents a Sanger Sequence Automatic Analysis Tool (SSAAT), a
software tool designed and implemented as a web application that provides a user-friendly
graphical interface such as those provided in proprietary tools. The tool has abilities to extract
raw data from sequence AB1 files, make base-calls, plot chromatogram, polymorphism
detection, sequence alignment and report generation. Furthermore, the tool is free and open source that can be easily accessed online through standard web browser applications. With the
above-mentioned features, SSAAT can be used by molecular biologist as an alternative to
proprietary tools and get comparable experience and DNA sequence analysis result
Mobile-based business-to-business platform for the pharmaceutical industry in Tanzania
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Masters of Science in Embedded and Mobile Systems (EMoS) of the Nelson Mandela
African Institution of Science and TechnologyThe right to the uppermost attainable standard of health is a fundamental human right. In everyday
life, mobile phones have become essential devices for most people in both developed and
developing countries. Paper-based ordering of medicines in the pharmaceutical industry is time
consuming and can enhance the spread of diseases such as COVID-19. Electronic ordering and
stock management can solve these challenges, but while it has been widely adopted in developed
countries, it remains underused in Tanzania. This study aimed to develop a mobile application
(DawaFasta) and web application which links wholesale and retail pharmacies in Tanzania, to
support electronic ordering and stock management. System and user requirements were collected
through questionnaires, interviews and observations from 105 wholesale and retail pharmacies in
Arusha, Dar es salaam and Kilimanjaro regions of Tanzania. The developed applications were
evaluated for acceptability and usability by 9 wholesale and 15 retail pharmacy personnel to assess
serviceability and usefulness. The results show that 96% found it very useful. The main reason is
to bridge the gap between wholesale and retail pharmacies and provide easy access to medications.
The 4% were not sure because they were unable to distinguish between legitimate and illegitimate
online pharmacies. The application was assessed as having good usability for online pharmacy
business purposes by wholesale and retail pharmacies. This application would need further
development in order to raise awareness and add more feature
Assessment of nutritional status and dietary aflatoxins exposure in Children in Singida District Council
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Master’s in Life Sciences of the Nelson Mandela African Institution of Science and
TechnologyFeeding practices are the critical determinant of the growth and development of children during
the first 1000 days of life with a long time effect on adulthood. This study aimed at assessing the
diversity and safety complementary foods in terms of aflatoxins (AF). A total of 290 households
with infants aged between 6-24 months were recruited from 10 villages in Singida District.
Mothers were interviewed on infant feeding practices and handling of food crops using a structured
questionnaire. Anthropometric measurements of index child were taken, followed by collection of
1 to 3 cereals based food samples used in complementary feeding in 180 households. A total of
218 flour samples made from maize, sorghum, millet, composite and fermented-germinated
sorghum locally known as magai and magai drink; from magai flour were collected. Food samples
were analyzed for aflatoxins using High-Performance Liquid Chromatography (HPLC).
Anthropometric measurements showed that 37.7% were stunted; 20.3% underweight and 8.3%
wasted. Furthermore, aflatoxin B1 was detected in 80 (36.7%) out of 218 complementary food
samples. Aflatoxin B1 levels ranged from 0.33 to 23.75 µg/kg whereas, total aflatoxins were
detected in 185 (84.9%) of 218 samples in a range of 0.47 to 289.28 µg/kg. However, mean dietary
exposure to all food were; magai drink (133.36 ng/kg body weight per day), composite flour (106.0
ng/kg body weight per day), maize flour (111.70 ng/kg body weight per day), sorghum flour (94.68
ng/kg body weight per day) and millet flour (92 ng/kg body weight per day)
Modeling the effect of binding kinetics in spatial drug distribution in the brain
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Masters in Mathematical and Computer Sciences and Engineering of the Nelson
Mandela African Institution of Science and TechnologyKey factors in the process of drug delivery in the human brain are blood-brain barrier, drug dis tribution and drug binding kinetics. Since human brain is entirely unavailable for experimenta tion, mathematical models have become vital for improved visualization of how each of the key
factors affects the delivery of drugs in the the human brain. In this study, a 3-dimensional math ematical model that incorporates drug transport across the blood-brain barrier, binding kinetics
and drug distribution within the brain extracellular fluid with a bidirectional bulk flow of the
brain extracellular fluid was developed and simulated. The model was developed assuming a
cube volume of a brain unit that is a union of the blood-brain barrier, brain extracellular fluid and
the blood plasma sub-domains. The model includes a set of partial differential equations and
boundary conditions that characterize the processes in the specified sub-domains. To determine
the effect of drug binding kinetics, the model equations together with their prescribed boundary
conditions were discretized by employing the finite difference method implicit schemes and the
model was analysed and simulated using MATLAB coding. Effects of drug binding kinetics
were investigated by varying the binding parameter values for both specific and non-specific
binding sites. All variations of binding parameter values were discussed and the results show
the improved visualization of the effect of binding kinetics in drug distribution within the brain.
For more realistic visualization, it was suggested to integrate more brain components that make
up the large volume of the brain tissu
Optimized processing method for producing Avocado and Mango seed-based composite flour for functional Foods
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Doctor of Philosophy in Life Sciences of the Nelson Mandela African Institution of Science
and TechnologyAvocado and mango seed kernels are considered as wastes although they are rich in essential
nutrients and bioactive compounds for human health. Lack of commercial application, presence
of anti-nutrients, difficulty in processing and little information on nutritional and functional
values contribute significantly to their underutilization. These factors underscore the need for
processing these seeds into consumable products to utilize them as functional foods. The aim of
this study was to optimize a processing technique capable of reducing antinutrients to acceptable
levels (above 50%), retain nutrients and functional values, and improve sensory qualities of
avocado and mango seeds-based composite flour for functional foods. Different processing
conditions for probiotic fermentation, boiling and soaking techniques were studied to optimize
processing conditions for the seeds. The antinutrients, antioxidant activity, total phenolics and
selected nutrients of the seeds were analyzed using standard analytical methods. Furthermore,
avocado and mango seeds-based composite flour was formulated using Nutrasheets integrated
with the USDA National Nutrient Database for Standard Reference. The formulated composite
flour was assessed for safety and quality parameters for a period of 84 days under different
storage temperatures. The results showed that all processing techniques significantly (p < 0.05)
reduced the antinutrients by over 50% for processed avocado and mango seed kernels. The
highest total phenolics and antioxidant activity (IC50) for both seeds were observed at a
fermentation temperature of 37oC with Lactobacillus plantarum. Soaking and boiling reduced
the analyzed minerals in both avocado and mango seed kernel except for potassium and zinc on
soaked mango seeds, whereas probiotic fermentation retained 100 % or increased the
concentration of the analyzed minerals, ascorbic acid and α-tocopherol. In contrast, boiling and
soaking reduced the contents of ascorbic acid and antioxidant activity of the analyzed samples.
The Nutrasheets analysis showed that the formulated composite flour can achieve the nutritional
and functional values for the functional foods. The shelf life analysis showed that 115 days (4
months) is the maximum shelf life for the flour where all the assessed safety and quality
parameters can still be within the maximum recommended tolerable limits for human
consumption. Therefore, the results of this study indicate that unlike boiling and soaking
methods, the probiotic fermentation is an optimized processing method which can significantly
reduce the antinutrients to acceptable levels, retain nutrients and bioactive compounds, and
improved sensory attributes of avocado and mango seeds-based composite flour for functional
foods
Cropping patterns along an altitudinal gradient and their implications to wildlife conservation in Rombo, Tanzania
Get PDFThis research article published by Elsevier B.V., 2021Ecosystem and livelihood sustainability of small-scale farmers in Eastern Africa are often challenged by climate change and unsustainable land use practices. Little is known on the small-scale
temporal processes of cropping systems in relation to long-term climatic conditions. To understand the climatic influence on the cropping patterns, and its implications to wildlife/elephant
conservation, our study used a combination of time-series datasets on crop and climate as well as
geo-spatial layers spanning more than three decades. To validate the information analyzed from
secondary data, we carried out participatory observation and interviews, whereby about 5% of
village households were selected along an altitudinal gradient of Rombo area, Tanzania. We
generated land use change maps using Geographical Information System (ArcGIS 10.4) and used
Spearman’s correlation analysis to assess the influence of rainfall, temperature, and crop yield on
the observed longitudinal changes in the crop types and other land use patterns both within and
across altitudinal gradients. We found that perennial crops like coffee and banana concentrated in
upper agro-ecological zones, with a clear division line above 1230 masl while seasonal crops like
maize and beans were mostly cultivated in lowlands (below 1230 masl). The results further
showed that coffee yields significantly declined with higher average annual minimum temperatures over the last 16 years. Within the same time period, there was a disproportionate shift from
coffee to seasonal crop cultivation such as maize and beans. Elephant numbers declined by about
38%, while human settlement area increased by 28% over the last 30 years. We conclude that
changes in land use and shifts in climate and cropping patterns have important implications for
elephant conservation and sustainability of the ecosystem in Rombo area, Tanzania
Detection of Username Enumeration Attack on SSH Protocol: Machine Learning Approach
Get PDFThis research article published by MDPI, 2021Over the last two decades (2000–2020), the Internet has rapidly evolved, resulting in symmetrical and asymmetrical Internet consumption patterns and billions of users worldwide. With the immense rise of the Internet, attacks and malicious behaviors pose a huge threat to our computing environment. Brute-force attack is among the most prominent and commonly used attacks, achieved out using password-attack tools, a wordlist dictionary, and a usernames list—obtained through a so-called an enumeration attack. In this paper, we investigate username enumeration attack detection on SSH protocol by using machine-learning classifiers. We apply four asymmetrical classifiers on our generated dataset collected from a closed-environment network to build machine-learning-based models for attack detection. The use of several machine-learners offers a wider investigation spectrum of the classifiers’ ability in attack detection. Additionally, we investigate how beneficial it is to include or exclude network ports information as features-set in the process of learning. We evaluated and compared the performances of machine-learning models for both cases. The models used are k-nearest neighbor (K-NN), naïve Bayes (NB), random forest (RF) and decision tree (DT) with and without ports information. Our results show that machine-learning approaches to detect SSH username enumeration attacks were quite successful, with KNN having an accuracy of 99.93%, NB 95.70%, RF 99.92%, and DT 99.88%. Furthermore, the results improve when using ports information
IoT-based system for automated floodwater detection and early warning in the East Africa Region: a case study of Arusha and Dar es salaam, Tanzania
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Master of Science in Embedded and Mobile Systems of the Nelson Mandela African
Institution of Science and TechnologyClimate change is a major cause of the increase of environmental natural disasters like floods,
droughts, and storms. Although several countries have been affected by such natural disasters,
the East African region is one of the most affected. This work focuses on floods as the most
frequent disaster in the East African region where 280 died and about 2.8 million people were
affected from the floods that occurred in 2019 alone. Different techniques have since been
developed to mitigate the effects of floods. However, the methodologies used have not
responded to the identified problems that include lack of community awareness, information
inadequacy, and low-cost systems. To solve these problems, the present study aims at
developing a low-cost system that detects and alerts the community on upcoming flood
incidents. The proposed floodwater detection and early warning system comprise of three units.
The sensing unit continuously monitors environmental parameters using ultrasonic,
temperature and humidity sensors. The processing unit processes and analyses the collected
data from sensors then, the alerting unit alerts the community and local authorities using a
buzzer and a Short Message Service notification. The system uses the Global System for
Mobile Communication to provide internet connectivity which enables data to be collected,
stored, and monitored in the cloud. The system was implemented at Themi river and results
showed that floods can be detected and the community near the flood-prone area alerted early.
Therefore, the use of the developed system in flood-prone areas can contribute to
environmental disaster risk mitigation