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Optimization of sub- and supercritical water gasification of rice husk enhanced with iron-doped alkaline-earth catalysts
Get PDFA Thesis Submitted in Fulfilment of the Requirements for the Degree of Doctor of Philosophy in Sustainable Energy Science and Engineering of the Nelson Mandela African Institution of Science and TechnologyBiomass is a promising renewable energy source widely available worldwide, particularly in
developing countries where clean and affordable energy is a major problem. Biomass gasification
is an attractive technology that can transform biomasses into a more versatile fuel known as
syngas, tar (bio-oil) and biochar. Syngas is a hydrogen-rich gas that could promote a clean and
green energy and promote the agriculture sector. The utilisation of syngas would reduce
dependence on fossil-based fuels and eventually reduce the carbon footprints. The gasification
technology faces operational challenges; one of the problems is tar formation, slow char
gasification reaction, and poor performance of catalysts. These challenges are influenced by
inappropriate operating conditions and the precursors employed in catalyst synthesis. In this
study, the optimisation of noncatalytic and catalytic gasification of rice husk is reported. The rice
husk biomass was gasified under subcritical and supercritical water conditions in a batch
autoclave reactor. The effect of temperature (350-500°C), residence time (30-120 minutes), and
feed concentration (3-10 wt%) is optimised. Moreover, the effect of the addition of natural,
calcined and Fe doped limestone and dolomite catalysts on the gasification yield is studied using
a response surface methodology. The catalyst was prepared by a facile incipient wetness process
using chlorine- and sulphur-free iron (III) ammonium citrate precursor. Optimisation of
operating conditions suggests a quadratic model for gasification efficiency, gas volume, char
yield, and gravimetric tar. The findings revealed that higher temperatures, longer residence times
and lower feed concentrations favoured high gas yields. The lowest tar yield obtained was 2.98
wt%, while the highest gasification efficiency and gas volume attained was 64.27% and 423
mL/g, respectively. The findings of the catalyst characterisation revealed that the predominant
reactive site of Fe/limestone catalyst is iron oxide, calcium ferrite, and calcium oxide. Under all
conditions tested, the manufactured catalyst was highly active in promoting char gasification,
gas volume and gasification efficiency. Tar yield was substantially promoted at low temperatures
and high feed concentrations, but at high temperatures and low feed concentrations (500oC, 3
wt%), tar formation was suppressed by 22%, while char gasification was enormously enhanced
by 65%. The maximum gas yield of 560 mL/g biomass was obtained under the catalytic
conditions of 5%Fe/limestone, 15% catalyst loading, 500oC, 120 minutes, and 3 wt% feed
concentrations. Therefore, these findings revealed that the rice husk's energy content could be
harnessed using supercritical water gasification to obtain substantial fuel products
Development of an Algorithm for Plagiarism Detection
Get PDFA Dissertation Submitted in Partial Fulfillment of the Requirements for the Degree of Master’s in Information and Communication Science and Engineering of the Nelson Mandela African Institution of Science and TechnologyFor many years, plagiarism has remained a serious problem in Higher Learning Institutions
(HLIs). Despite having adverse effects on the quality of education, plagiarism has been rapidly
increasing in HLIs across the globe. Many researchers agree that the ease of access to information
over the internet has made plagiarism a common occurrence in Tanzanian HLIs. In order to
address this problem, many Tanzanian HLIs have enacted strict anti-plagiarism policies that
require the use of software to detect plagiarism cases efficiently. Although many free and
commercial plagiarism detection software exist, HLIs in Tanzania face numerous challenges in
finding appropriate tools. The accuracy and effectiveness of freely available plagiarism detection
software have been continuously questioned as they often provide inconsistent results. Moreover,
commercial software that promise better performance have high annual subscription fees that
are not easily affordable by HLIs in developing countries. This study aimed to address the
need for affordable and reliable plagiarism detection tools in Tanzanian HLIs by developing an
efficient algorithm for plagiarism detection. The study employed a systematic approach that
involved different stakeholders in Tanzanian HLIs, including students, academic staff, and support
staff. Questionnaires, unstructured interviews, and thorough literature analysis were used to
identify the stakeholders’ needs and establish user requirements. The study proposed a plagiarism
detection algorithm using a machine learning approach to information extraction, graph-based
information retrieval, and semantic textual similarity methods. A web-based plagiarism detection
system that implements the proposed algorithm was developed using open source technologies
such as Symfony web framework, Neo4j graph database, MySQL database, and RabbitMQ.
User Acceptance Testing (UAT) results concluded that the stakeholders positively accepted
the developed algorithm. Furthermore, the developed web-based plagiarism detection system
has received a Copyright Clearance Certificate from The Copyright Association of Tanzania
(COSOTA), and The Committee of Vice Chancellors Principles and Provosts of Tanzania (CVCPT)
has recommended the deployment of the system in Tanzanian HLIs
Teaching research data management courses in higher learning institutions in Tanzania
Get PDFThis research article was published by Emerald Publishing Limited, 2022Purpose – The study investigated teaching research data management (RDM) courses in higher learning
institutions (HLIs) in Tanzania to enable postgraduate students to work with their research data.
Design/methodology/approach – The study triangulated research methods. Postgraduate students were
investigated using survey questionnaires to learn about their needs and perceptions of the teaching RDM
courses in HLIs. Key informants (academicians, information and communication technologists and library
staff) were also investigated using in-depth interviews to explore their experiences and knowledge of teaching
RDM courses. SPSS statistical software was used for analysing quantitative data; qualitative data were
analysed thematically.
Findings – A total of 70 questionnaires were distributed to postgraduate students with a returning rate of 44
(69%). On the other hand, 12 key informants were interviewed. A low level of RDM literacy was revealed among
38 (86%) respondents. Most respondents 40 (91%) reported the need for HLIs to start teaching RDM courses. A
lack of skills and knowledge in teaching RDM courses was revealed among key informants. The competency based, adaptive and constructive teaching techniques were selected for teaching RDM courses, whereas
intensive training and online tutorials were revealed as teaching formats.
Research limitations/implications – This study focused on teaching RDM courses in HLIs. The survey
questionnaires were distributed to all 2nd year postgraduate students, however, the findings cannot be
generalised to all postgraduate students due to the response rate obtained. The findings obtained from key
informants can also not be used as a basis for generalization across HLIs.
Practical implications – This study concluded that postgraduate students need to be well equipped with
skills and knowledge on RDM and its related concepts; teaching RDM courses should be regarded as a
continuous programme for benefit of students, researchers and the community at large.
Social implications – Appropriate teaching of RDM courses among students not only ensures that students
meet the funders’ and publishers’ requirements, but also encourages students to store and share their research
among researchers worldwide; thus increasing collaboration and visibility of the datasets and data owners
through data citations and acknowledgements.
Originality/value – This is a comprehensive study that provides findings for HLIs to teach RDM courses in
HLIs, especially for postgraduate students. The findings revealed the need for teaching RDM courses in HLIs.
The study provides the basis for further RDM research in HLIs and research institutions
Web-based personal dose management system for data recording on dosimeter usage: a case of Tanzania atomic energy commission
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 TechnologyModern technology drives the world, increasing performance while reducing labour and time
expenses. Tanzania Atomic Energy Commission (TAEC) tracks employees’ levels of
exposure to radiation sources using dosimeters. According to legal compliance, workers wear
dosimeters for three months and one month at the workplace. However, TAEC has problems
in tracking, issuing, and returning dosimeters because the existing tracking is done manually.
The study intended to develop a Personal Dose Management System (PDMS) that processes
and manages the data collected by dosimeters for easy and accurate records. During the
requirements elicitation process, the study looked at the existing system. PDMS’ requirement
gathering included document reviews, user interviews, and focused group discussions.
Development and testing of the system were implemented by applying the evolutionary
prototyping technique. The system provides a login interface for system administrators,
radiation officers, and Occupational Exposed Workers. The PDMS grants TAEC Staff access
to monitor individual exposed workers, prints individual and institutional reports and
manages workers' information. The system reminds the users when to return dosimeters to
TAEC, generates reports, and facilitates dispatching and receiving dosimeters effectively.
PDMS increases efficiency and effectiveness while minimizing workload, paperwork, and
inaccurate records. Although the existing systems are beneficial to their respective countries,
they are designed based on the specific institution. The system developed simplifies the
procedures for requesting dosimeters, reminding users when to return the dosimeter, and
printing quarterly and annual reports for individuals and institutions. Therefore, based on the
results obtained from the system, it is recommended to use the system to improve dosimeter
data management at the institution
Antifungal activity of selected pesticidal plants against phaeoisariopsis personata and phytochemical analysis, central Tanzania
Get PDFA Thesis Submitted in Fulfillment of the Requirements for the Degree of Doctor of Philosophy in Life Sciences of the Nelson Mandela African Institution of Science and TechnologyThe late leaf spot (LLS) caused by Phaeoisariopsis personata L., is the most serious fungal
disease of groundnut worldwide. The LLS causes considerable damage to groundnuts leading
to leaf defoliation and consequently reduces pod yields by more than 50%. Research was
carried out to evaluate the antifungal activity of Parthenium hysterophorus, Azadirachta
indica and Jatropha curcas against P. personata and analyse the possible compounds
exhibiting antifungal properties at the Tanzania Plant Health and Pesticide Authority
(TPHPA)-Arusha, Tanzania. The field survey results indicated that the LLS disease of
groundnuts prevailed in the central zone of Tanzania with overall disease incidences between
(54.65-84.70%) and severities (4.9-7.00). This finding provides alerts to the global plant
health regulators suggesting a proper management skill. The evaluation the selected pesticidal
plants revealed that all the plant extracts showed antifungal activities against P. personata
under in vitro and in vivo (screen-house) conditions. The methanolic leaf extracts of all tested
plants offered higher antifungal activities with >75% inhibition of mycelial growth of P.
personata compared to control (0% inhibition). Similarly, the application of methanolic leaf
extracts of selected plant extracts on groundnuts seedlings grown in pots under screen-house
condition at the highest concentration (0.5 mg/ml) exhibited antifungal potentials against P.
personata by reducing the disease incidence being 14.30% and severity of 2.22 compared to
chloroform (17.44%, 4.07) and ethyl acetate (20.56%, 4.26) leaf extracts. Subsequently
groundnut seed yield/plant was greater 45.09 g for crop treated with the most effective plant
extract (A. indica at 0.5 mg/ml) as compared to untreated 7.76 g. Furthermore, the
phytochemical analysis of the selected pesticidal plants by GC-MS identified important
phytocompounds with antifungal properties from the tested plant extracts mainly;
hexadecanoic acid ethyl ester, methyl salicylate, phytol, phenol 2,4-bis (1,1-dimethylethyl),
n-hexadecanoic acid, hexadecanoic acid methyl ester and hexadecane. The presence of these
antifungal phytocompounds in the selected plants is associated with their effect on the P.
personata. A further study under field condition is recommended on the tested plants (P.
hysterophorus, A. indica and J. curcas) on possibility of developing bio fungicides for the
management of groundnut LLS disease in Tanzania
Development of swahili speaking body weight scale for visually impaired people in Tanzania
Get PDFA Project Submitted in Partial Fulfilment of the Requirements for the Degree of Masters of Science in Embedded and Mobile Systems of the Nelson Mandela African Institution of Science and TechnologySpeaking weight scale is an important low vision health aid which measures and announces out
the measured weight. It is valuable in numerous applications such as Bathroom scale, Kitchen
scale and more. Different talking scales have been developed for blind community. Many talking
scales have language option for English, German, French or Spanish. However, only limited
work exists for Swahili speaking visually impaired community in East African Community
(EAC) given the fact that no talking scale can announce weight in Swahili, which is the common
language in EAC. Therefore, this project aims to develop a Swahili speaking weighing machine
to assist visually impaired people in Tanzania. The proposed speaking scale is divided into two
major parts. On the front-end of the design, sensors are used to capture weight parameters. The
captured values are mapped onto sequence of voice patterns. The back-end consists of
transferring a sequence of voice patterns to a loudspeaker whereby the voice patterns are stored
on an SD card. Finally, the developed device has been evaluated on several objects (certified
scale calibration weights) with known weights. Each object was reweighed two times. Placed
certified calibration weights on the scale and note the output. Took the measured object off the
scale and let the scale return to zero. Placed the same object on the scale again. Noted the output
again. The results then showed that the scale displayed the same weights on each object. The
expected weight of given objects was then compared with the recorded ones to assess the
performance of the scale. The results then showed that the scale is able to measure objects,
displays digital output of measured weight and announce it in Swahili language within the
accuracy of 1% error range of the actual weight. The proposed device has a great potential as a
low vision health aid for Swahili speaking. The features of this device can be further improved
to increase the autonomy of blind people to use the device and navigate to the device’s location
safely
Prevalence and predictors of self-medication with antibiotics in selected urban and rural districts of the Dodoma region, Central Tanzania: a cross-sectional study
Get PDFThis research article was published by Springer Nature, 2022Background: Antibiotic resistance is a global health threat driven partly by self-medication with antibiotics (SMA).
This study aims to assess the prevalence and predictors of SMA in selected rural and urban communities of the
Dodoma region, Central Tanzania.
Methods: This cross-sectional study was conducted in Chemba District Council (rural) and Dodoma City Council
(urban) from August to November 2019 using multistage stratifed random sampling. Data were collected through
face-to-face interviews using structured questionnaires.
Results: A total of 430 respondents were interviewed in Chemba District Council (rural) (161/430) and Dodoma City
Council (urban) (269/430). The prevalence of SMA was 23.6% (38/161) among rural respondents and 23.4% (63/269)
among urban respondents. The median amount of SMA in both settings was 2, while the maximum amounts
were 4 and 5, respectively. SMA among rural and urban participants was associated mostly with perceived cough
(76.3%/82%), body pain (71.1%/41.5%) and fever (63.2%/39.7%), and amoxicillin was the most commonly used
antibiotic in both settings (47.3%/41%). Rural participants who reported a shorter perceived distance to a health care
facility than to a drug outlet were 58.9% less likely to practise SMA (adjusted OR: 0.421; 95% CI: 0.388, 0.458; p<0.001),
whereas SMA decreased by 16.3% among urban participants who reported a shorter perceived distance to a health
care facility than to a drug outlet (adjusted OR: 0.837; 95% CI: 0.755, 0.929; p<0.001). SMA was 17.3% lower among
farmers than among nonfarmers in the urban area (adjusted OR: 0.827; 95% CI: 0.716, 0.955; p=0.01), while farming
had no efect in the rural area.
Conclusions: The prevalence of SMA is similar among participants in rural and urban districts. In both localities,
a shorter perceived distance to a drug outlet is an independent risk factor for SMA, while having health insurance
reduces the risk. Equally weighted interventions to reduce SMA are required in rural and urban communities
Morphological and physiological responses of the invasive plant gutenbergia cordifolia to varying biophysical conditions
Get PDFA Dissertation Submitted in Partial Fulfillment of the Requirements for the Degree of Master’s in Life Sciences of the Nelson Mandela African Institution of Science and TechnologyThis study assessed the effects of varying water stress levels on morphological and
physiological traits of an invasive plant Gutenbergia cordifolia (G. cordifolia) under field and
screen house conditions and the responses of these traits on performance G. cordifolia under
long and short rain seasons in the Ngorongoro Crater, Tanzania. The water stress level
assessment was conducted in the screen house at the Nelson Mandela African Institution of
Science and Technology (NM-AIST) following a completely randomized design (CRD) while
field assessment was conducted in Ngorongoro Conservation Area (NCA). While the
maximum and minimum plant heights in the screen house experiment were observed under
flood and drought water stress, respectively, the maximum and minimum root collar diameter
(RCD) were observed under moderate flood and drought water stress, respectively. Generally,
the number of leaves was highest under moderate flood stress and lowest under drought stress.
The largest and smallest leaf surface areas (LSA) were observed in flood and drought water
stress conditions, respectively. While a decrease in leaf chlorophyll was observed under
drought water stress, an increase in leaf anthocyanin levels was observed under flood stress. In
comparing field and screen house traits; both maximum G. cordifolia height and highest
number of leaves were observed under screen house. While the largest and smallest LSA were
observed in the field condition and screen house respectively, both the maximum root and shoot
fresh and dry weights were observed under field condition. Both leaf anthocyanin and
chlorophyll were higher under field compare to screen house. While both the maximum height
and the largest RCD were observed during long rain season the highest number of leaves per
plant was observed during short rain. Both highest root fresh and dry weight were observed
during long rain. The maximum leaf chlorophyll level was observed during short rain season
while the minimum was observed during long rain season. The findings from this study indicate
that the establishment and spread of G. cordifolia is likely to be favoured by projected East
African rainfall (2050-2100) as suggested by Platts et al. (2015) and inform conservation and
management authorities on how growth and performance is likely to be in the future under
changing climate and the need of integrating this information in its future management
strategies. The study further suggests that efforts to minimize impacts of an invasive G.
cordifolia in a changing climate must include a good understanding of G. cordifolia behaviour
under extreme events so as to prepare effective management strategies and actions
Development of Plant-Based Yoghurt Rich in Bioavailable Essential Nutrients and Bioactive Compounds from Ingredients Available in East Africa
Get PDFThis research article published by Enviro Research Publishers, 2022The main aim of the present study was to formulate a convenient plant based yoghurt (PBY) with essential nutrients and bioactive compounds
comparable to that of cow's milk using locally available ingredients in
East Africa. Linear programming (LP) was applied for ratios optimization.
The fermentation technique was deployed using commercial yoghurt culture
(Streptococcus thermophilus and Lactobacillus bulgaricus) to develop
a palatable and functional yoghurt. Laboratory analysis was conducted to
validate the nutritional and functional values calculated by LP, and their relative
difference was also calculated. PBY was analyzed for lactic acid bacteria
(LAB) viability and storage stability for the 1st, 7th, and 14th day of refrigeration
storage (4°C). Results showed that LP-optimized PBY could be formulated
at a low cost of USD 0.9/kg, which is 60% cheaper than Alpro natural PBY.
The formulation contained 37.87% and 18.88% of total Monounsaturated Fatty
acids (MUFAs) and total Polyunsaturated Fatty acids (PUFAs), respectively.
PBY riches in essential nutrients and functional properties enough to meet the
Recommended Daily Intake (RDI) for 2-10-year old children. Formulated PBY
were microbiologically stable for 14 days of storage and were found within
acceptable standards specified by the Food Standard Australia New Zealand
(FSANZ) and the East African Standard for yoghurt (EAS33:2006). Plant-based
yoghurt rich in nutrient bioavailability and bioactive compounds can be formulated
using locally available ingredients and considered as an alternative to yoghurt
Development of context-specific dietary guidelines for managing nutrition-related disease conditions among hospitalised patients in Tanzania
Get PDFA Dissertation Submitted in Partial Fulfilment of the Requirements for the Degree of Master of Science in Human Nutrition and Dietetics of the Nelson Mandela African Institution of Science and TechnologyBarriers to adequate food intake among hospitalised patients with nutrition-related disease
conditions such as diabetes, cancer, kidney disease, and hypertension, are multifactorial and
complex. Due to this, these disease conditions require multi-level interventions, including a
change in the attitude and improved awareness towards food among healthcare staff and
hospitalised patients. The priority interventions need to be feasible in practice, particularly in
terms of the availability, affordability, accessibility, and time. This can be successful when
specific food-based dietary guidelines for each disease condition are in place. Unfortunately,
specific dietary guidelines for managing nutrition-related chronic disease conditions among the
hospitalised patients are currently not well established in Tanzania. This significantly contributes
to delayed recovery of patients and increased economic burden to families and communities due
to increased medical costs resulting from prolonged length of hospital stays, readmission, and
mortality. Our study aimed to develop context-specific food-based dietary guidelines which
favour healthy eating in the light of gut microbiome to guide health care professionals and
nutritionists to make rational decisions in planning diets for these patients. A cross-sectional
study was conducted to collect data on dietary intake, dietary patterns, food price and availability
to inform the formulation of specific food-based dietary guidelines for hospitalised patients in
Tanzania. Moreover, a 7-day weighed food record (WFR) was used to assess dietary intake data
among 400 hospitalised patients with nutrition-related chronic diseases. Likewise, data on prices
of commonly consumed foods were obtained from hospitals’ requisition books, nearby markets
and shops. Furthermore, a linear goal programming was used to optimize dietary intake patterns
for hospitalised patients with nutrition-related disease conditions by developing food-based
dietary guidelines based on the study’s context. The analysis showed that whole grains mainly
dominated the observed hospital dietary patterns. However, diet optimization using linear
programming (LP) provided adequate dietary patterns with nutrient-dense foods for each food
group. The LP findings informed the process of formulating context-specific optimal dietary
guidelines that use culturally acceptable food ingredients, and which favour healthy eating in the
light of gut microbiota for managing nutrition-related chronic diseases for hospitalised patients