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IoT based system for monitoring and control data center temperature at Habari Node Company
Get PDFA Project Report Submitted in Partial Fulfillment of the Requirements of the Award the Degree of Master of Science in Embedded and Mobile Systems of the Nelson Mandela African Institution of Science and TechnologyThe Internet of Things (IoT) Based Systems have improved the way of life of companies as
well as individuals. Through interconnected objects via intranet and Internet, IoT
technologies enhance the productivities of businesses by reducing the wastage of time,
reducing the expenses of the businesses by its low-cost property. The IoT is empowered by a
system of detection, actuation, control, and cloud storage. IoT technologies should be applied
to monitor the change of the value of valuables like temperature, voltage, gas and liquid level,
etc.; it helps to get the record of the change in the value of the valuables detected. The
proposed system was developed to monitor and control data center temperature through
ESP32 board, DHT22 module, relays and ThingSpeak cloud. To significantly reduce the
power consumption of the cooling devices, the system uses a cooling device backup which
can be controlled by a microcontroller through a smartphone over the Internet. Moreover, the
system assists the data center manager by automatically switching on the backup in case of
the failure of one working cooling device. However, an email address and SMS are sent to
the data center manager at any time when there is a collected value that is not in the normal
temperature range. As a result, the project enhances the productivity of the company by
reducing the cost expended in the data center infrastructure, and by reducing the activities
performed by a data center manager
Assessment of trace and radioactive elements risk in the artisanal and small-scale gold mining sector
Get PDFA Dissertation Submitted in Partial Fulfilment of the Requirements for the Degree of Doctor of Philosophy in Environmental Sciences and Engineering of the Nelson Mandela African Institution of Science and TechnologyCurrently, the mining industry in Tanzania faces significant challenges including a significant
policy research gap. In this work, different indices were applied to assess the health risk of
people living and working in Rwamagasa artisanal and small-scale gold mines compared to
existing Tanzanian and international standards. This dissertation has focused on quantifying
and assessing the risk of selected trace and radioactive elements in a small-scale mining area.
Furthermore, the present study analyzed and thus gives some recommendations on issues
surrounding the Tanzanian mineral and mining policymaking process. Building on existing
work on miner’s health risk, the present study asks: What are the levels of trace and radioactive
elements in the studied mining areas compared to the recommended local and international
limits? What is the health risk due to trace and radioactive elements exposure to mine workers
and the surrounding communities? What are some of the deficiencies in the structure of the
Tanzanian mineral and mining regulatory framework that are relevant to the environment and
public health in artisanal and small-scale gold mines (ASGM)? The hyper pure germanium
detector (HPGe) was used for radioactivity analysis. The soil trace elements were analyzed
using the energy dispersive X-ray florescence (ED-XRF) technique. The radon gas levels were
measured using the Alpha Guard radon monitor. Different literatures survey digest were used
to assess the appropriate works on the regulatory and legal framework of the mining sector in
Tanzania. The levels of trace elements, carcinogenic and noncarcinogenic health risks revealed
that children were more at-risk compared to adults. The hazard index for all pathways was 1.77.
This index suggested that the residents of the studied sites were at a high risk of non carcinogenic effects due to mining operations. The carcinogenic risk for adults and children
was found to be 3.42×10-5
and 6.16×10-5
, respectively, which were higher than the tolerable
limit (1×10-6
). The results on radioactivity; mean effective dose; annual gonadal equivalent and
absorbed dose; radium equivalent; internal and external hazard indices; alpha and gamma
indices; and the radon gas revealed high values – approximately 60% higher than the levels that
were found in the control area. The Tanzania mining policy-making process needs to have a
circular model with the inclusion of scientific inputs as well as societal involvement at every
stage of formulation. The present study recommends further studies especially those that use
human samples and human subjects in attempting to discover more on the risk posed by mining
operations on human health. Also, sustainable mining awareness to people of Rwamagasa is
ii
recommended. Furthermore, the present study suggests developing a document that govern the
Tanzania artisanal and small-scale mining subsector
Mathematical modeling of fall armyworm spodoptera frugiperda infestations in maize crops and its impact on final maize biomass
Get PDFA Dissertation Submitted in Partial Fulfilment of the Requirements for the Degree of Doctor of Philosophy in Mathematical and Computer Sciences and Engineering of the Nelson Mandela African Institution of Science and TechnologyFall armyworm (FAW-Spodoptera frugiperda), a highly destructive and fast spreading agricul tural pest native to North and South America, poses a real threat to global food security. It
is estimated that intermittent FAW outbreaks could cause up to $US 13 billion per annum in
crop losses throughout sub-Saharan Africa. Considering this projected loss it is imperative that
various tools and techniques be utilized to infer on the various factors that affect FAW maize in teraction and in-turn affect the final maize biomass. Mathematical modeling has proved to be an
important tool that is capable of shedding light on the FAW-maize interaction dynamics. In this
study, three mathematical models were proposed to evaluate the impact of memory effects and
controls, seasonality and Integrated Pest Management strategy (farming awareness and larvae
predation) on FAW infestations in maize crops and on final maize biomass. Firstly, to evaluate
the impact of memory effects and control, a new dynamical system for FAW-maize biomass
interaction via Caputo fractional-order operator was proposed and analyzed. In the proposed
model, four equilibrium points which revealed the existence of a threshold parameter defined
by R0 were computed and analyzed. Further, it was observed that, R0, the average number of
newborns produced by one individual female moth during its life span was an integral compo nent for stability of the aforementioned model equilibria. Secondly, to evaluate the implications
of seasonality on FAW maize interaction and on the final maize biomass, a non-autonomous
mathematical model was proposed and analyzed. The analysis revealed that the model solution
was non-negative, unique, permanent and bounded admitting global asymptotic and continuous
periodic function. Further, the model was extended into an optimal control problem with the
aim of determining optimal pesticides and traditional methods that are capable of minimizing
FAW egg and larvae populations at minimum cost. Results from the study demonstrated that
a combination of pesticides use at low intensity with traditional methods at higher intensity
could eradicate FAW in a maize field in a period less than half the life span of the crop in the
field. Thirdly, to evaluate the impact of farming awareness campaigns and larvae predation,
a fractional-order model that incorporated farming awareness campaigns and larvae predation
was proposed and analysed. Overall, the study highlighted that, non-time dependent farming
awareness campaigns should be close to 100% all the time to eradicate the FAW. However,
when time-dependent farming awareness was implemented, it was observed that even less than
50% intensity level could lead to eradication of FAW. In all the proposed models, comprehen sive numerical simulations were carried out in MATLAB programming language to support the
analytical findings. In a nutshell, the results of this study showed that mathematical models can
be important tools to evaluate FAW and maize interaction dynamics
Ethnobotanical use, threat status and optimalenvironmental germination conditions for conservation of aloe species in Tanzania
Get PDFA Dissertation Submitted in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy in Life Sciences of the Nelson Mandela African Institution of Science and TechnologyThe genus Aloe is known for its use in healthcare and cosmetics. Many Aloe species are globally
threatened due to over-harvesting for trade and habitat destruction. In Tanzania, over-exploitation
threats some Aloe species with extinction, and yet little has been documented on the abundance,
bio-cultural uses, threats, seed biology and appropriate conservation measures. Semi-structured
questionnaires were used to obtain ethnobotanical information and perception of Aloe species'
threat factors from 236 respondents in Kilimanjaro, Tanga, and Mara and Katavi-Rukwa regions.
Geospatial Conservation Assessment software (GeoCAT) was used to assess the Area of
Occupancy and Extent of Occurrence of Aloe species. The temperature, light, scarification, KNO3
and salinity among the Critically Endangered and the Least Concern Aloe species were tested to
understand optimal environmental conditions for their optimal growth. For the Critically
Endangered A. boscawenii, an ideal concentration for sterilization and rooting hormone were
determined to promote tissue cultivations. A total of 23 Aloe species were identified, with A.
secundiflora being the most widely used species. Malaria and general stomachache in humans,
and Newcastle disease in chickens were frequently treated with Aloe species. Among the 22 Aloe
species re-assessed, two were categorized as Critically Endangered, ten as Endangered, five as
Vulnerable, one as Nearly Threatened and five as Least Concern. Aloe boscawenii was re discovered after not having been seen for more than six decades. The conservation status of the
Aloe species endemic to Tanzania and previously categorized as Critically Endangered were
upgradeed. All the tested Aloe species germinated best at moderate temperatures (25°C and 30°C)
and low KNO3 levels (0.01 mg/L). The Critically Endangered A. boscawenii was successfully
regenerated through tissue culture at 6% of NaOCl and rooted at NAA: IBA (2:1) concentration.
The genus Aloe is widely used across Tanzania, as such 77% (N = 22) of Aloe species assessed
in this study are threatened, mainly due to human activities. Hence, there is a need to formulate
laws and policies to protect Aloe natural habitats. Moreover, the Aloe seeds exhibited species specific responses to various environmental conditions (except for A. pembana). Furthermore,
tissue culture is an ideal conservation tool for the threatened species as it outperforms the
traditional methods
Structural and biophysical characterization of cassava linamarase and the role of solvents on linamarin’s properties: a computational study
Get PDFA Thesis Submitted in Fulfillment of the Requirements for the Degree of Doctor of Philosophy in Materials Science and Engineering of the Nelson Mandela African Institution of Science and TechnologyLinamarase and linamarin mainly from cassava have many applications ranging from food,
environmental to the medical industry. To better explore the potential of this enzyme and its
substrate, one needs to understand its interaction mechanism at the molecular and atomistic level.
In this thesis, the three‒dimensional (3D) structure of linamarase was built via homology
modeling. The developed model was used to determine the binding orientation and mechanism of
linamarin to the enzyme using molecular docking. Molecular dynamics simulation was used to
determine the stability of the built model and when complexed with the ligand. It was interesting
to note that complex 1 with the low binding‒free energy of ‒6.9 kcal/mol showed a larger Root
Mean Square Deviation (RMSD) value with two maxima at 0.255 and 0.310 nm compared to
complex 2 with the best binding‒free energy of ‒7.2 kcal/mol, whose RMSD value shows the
maxima at 0.19 nm. The end‒point free energy method based on Molecular Mechanics Poisson
Boltzmann Surface Area (MM/PBSA) was used to rescored binding free energy obtained from
docking calculations. The ensemble structure was observed to be relatively stable compared to the
modelled structure. Furthermore, the stability and conformational orientation preferences of
linamarin in different solvents was established using classical molecular dynamics, and found to
be solvent dependent. The effects of solvents on the stability and conformational preference is
pronounced by different probability density maxima of the measured reaction
coordinate/properties. Linamarin is observed to be stable in methanol followed by dimethyl
sulfoxide (DMSO) and least stable in water. Solvent polarity was observed to influence the
stability and conformation preference of the title compound. Linamarin exists in trans and gauche
conformations, the former was observed to be more stable in water than other solvents and the
latter in DMSO. The measured reaction coordinates, distance and dihedral angles ascertained that
the conformational preference is due to rotation at = ± 180o
and = ± 50o . Finally, the stability
of linamarin was also attributed to different numbers of inter and intra hydrogen bonds formed in
different solvents. Results presented in this thesis provides atomistic insights on the role of solvents
polarity on linamarase‒linamarin complex interaction and stability. The findings provide
important information on the application of linamarase and linamarin in different fields including
food processing and in drugs
Survival Mechanisms and Management Challenges Associated with Silver Leaf Whitefly on Tomato in Africa: A Review
Get PDFA research article was published by International Journal of Agriculture & Biology Volume 27, 2022Silver leaf whitefly (Bemisia tabaci Gennadius) (Hemiptera: Aleyrodidae) is a polyphagous winged insect pest that causes high yield losses in tomatoes and other vegetable crops globally. To combat the infestation by the silver leaf whitefly and other insects, tomato growers use cultural and synthetic chemical-based methods. However, the silver leaf whitefly continues to dominate the tomato production systems. Some of the reasons for such continued dominion by the silver leaf whitefly in tomato include among other reasons; little understanding of the mechanisms for survival of the insect pest by tomato production stakeholders which consequently results in difficulties in making appropriate pest management decisions, presence of diverse hosts, the ability of the silver leaf whitefly to develop resistance to synthetic pesticides and ineffective techniques used by tomato grower in combating the insect. Of these challenges, this review discusses the mechanisms for survival of the insect, current pest management options and recommendations for a way forward concerning the silver leaf whitefly management in Africa
Plant-Rich Field Margins Influence Natural Predators of Aphids More Than Intercropping in Common Bean
Get PDFThis research article was published by MDPI in 2022Field margins support important ecosystem services including natural pest regulation. We
investigated the influence of field margins on the spatial and temporal distribution of natural enemies
(NEs) of bean pests in smallholder farming systems. We sampled NEs from high and low plant
diversity bean fields using sweep netting and coloured sticky traps, comparing monocropped and
intercropped farms. NEs collected from within crops included predatory bugs, lacewings, predatory
flies, parasitic flies, parasitic wasps, lady beetles, and a range of other predatory beetles; with the
most dominant group being parasitic wasps. Overall, high plant diversity fields had a higher number
of NEs than low-diversity fields, regardless of sampling methods. The field margin had a significantly
higher number of lacewings, parasitic wasps, predatory bugs, syrphid flies, and other predatory
beetles relative to the crop, but beneficial insects were collected throughout the fields. However, we
observed marginally higher populations of NEs in intercropping than in monocropping although the
effect was not significant in both low and high plant diversity fields. We recommend smallholder
farmers protect the field margins for the added benefit of natural pest regulation in their fields
Informing versus generating a discussion: Comparing two approaches to encouraging mitigation of soil erosion among Maasai pastoralists
Get PDFThis research article was published by Elsevier in 2022Soil erosion is a critical problem for pastoralist societies that rely on healthy grazing land for their livelihoods. Previous research suggests that unsustainable land management practice is one of the factors exacerbating soil erosion, and that willingness to adjust this practice is closely linked to community land protection norms. The present research explores approaches to building stronger community norms and intentions linked to mitigating soil erosion among Maasai pastoralists in Northern Tanzania. In particular, we compare two impact approaches based on the information deficit model (exposure to scientific information) and the social identity framework (a group-based discussion). The results demonstrate that the information deficit approach results in stronger perceived land protection norms and, indirectly, stronger intentions, as compared to the discussion-based approach. We discuss contextual features that should be taken into account when interpreting these findings and suggest these may be key for impact approach choices
Elements of agroecological pest and disease management
Get PDFThis research article was published by the University of California Press in 2022The development of large-scale monocropped agrisystems has facilitated increased problems with pests and
diseases, perpetuating the reliance of farmers on synthetic pesticides. The economic success of synthetic
inputs has, however, been achieved at a high cost to the environment through the loss of biodiversity,
depletion of soil quality, greenhouse gas emissions, and disrupting the ecosystem services that can
otherwise help mitigate losses caused by pests and diseases. Environmentally benign alternatives for pest
and disease management are urgently needed and are now widely recognized as essential for sustainable food
and agriculture. The Food and Agriculture Organization, for example, has published the 10 elements of
agroecology as a framework for the transformation of agriculture. Agroecology combines ecological and
social concepts and principles to develop sustainable food and agricultural systems by harnessing nature based solutions that are tailored to farmers’ needs. Plant-based biopesticides, for example, offer an
alternative to synthetic pesticides that are less harmful to the environment and nonpersistent, yet
effective at managing pests and have a long tradition of use among farmers so are more socially
acceptable. Here, we provide a critical assessment of how nature-based approaches to pest and disease
management comply with the 10 elements of agroecology and show how they integrate with other
ecosystem services through farmer participatory research. We conclude that the adoption of nature-based
solutions for pest management addresses all 10 elements of agroecology and provides an entry point to
promote sustainable farming practices among farmers more widely
A comparative analysis of determinants of low birth weight and stunting among under-five children of adolescent and non-adolescent mothers using the 2015/16 Tanzania demographic and health survey
Get PDFA Dissertation Submitted in Partial Fulfillment of the Requirements for the Degree of
Master of Science in Public Health Research of the Nelson Mandela African Institution of
Science and TechnologyIn Tanzania, adolescent pregnancies increased from 23% to 27% between 2012 and 2015. The rises
have been linked to poor birth outcomes, pregnancy complications, childhood malnutrition, and
maternal and child deaths. Using data from the 2015 Tanzania Demographic and Health Survey,
this study investigated the factors associated with low birth weight (LBW) and under-five stunting
among adolescent and non-adolescent mothers. Data from 13 266 women collected as part of the
Tanzania Demographic and Health Survey in 2015/2016 were re-analyzed using STATA version
14 software while taking survey design into account. The outcome variables were low birth weight
and stunting. Logistic regression models were used to identify factors that contributed to LBW and
stunting in children born to adolescent and non-adolescent mothers. After controlling for potential
confounders, this study discovered that non-adolescent mothers had a lower risk of having LBW
babies than adolescent mothers (AOR = 0.34; 95 per cent CI: 0.22-0.50). Maternal malnutrition
(AOR = 2.29; 95 percent CI: 1.43–3.67), divorce, separation, or widowhood (AOR = 1.76; 95
percent CI: 1.24–2.50), and fewer than four antenatal care (ANC) visits (AOR = 0.64; 95 percent
CI: 0.49–0.83) were all associated with LBW. Stunting in children was not related to maternal age.
Maternal high socioeconomic status (AOR = 0.69; 95% CI: 0.57-0.84) and maternal obesity or
overweight (AOR = 0.77; 95% CI: 0.64-0.92) were associated with stunting. Stunting was found
to be significantly associated with birth weight, gender, and age. Maternal age predicted LBW but
not stunting. To reduce poor birth outcomes, a multi-sectoral approach is required to address
childhood stunting and teenage pregnancies