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Environmental factors and non-chemical methods to suppress growth of the invasive plant Gutenbergia cordifolia
Get PDFA research article was published by Acta Oecologica Volume 119, August 2023Little is known about preferred environmental conditions and non-chemical control of invasive Gutenbergia cordifolia. We assessed the effects of different A. annua crude extract concentrations, synthetic herbicide (glyphosate), fire regime and shade to G. cordifolia germination, shoot and root dry biomass, seedling height and leaf chlorophyll. High concentrations (75%) of A. annua crude extracts significantly reduced germination percentage of G. cordifolia by 25% (F2,4=77.2, p < 0.001), and suppressed shoot and root dry biomass (F2,4 = 80.3, p < 0.001; F2,4=46.104, p < 0.001, respectively) as well as seedling height and leaf chlorophyll (F2,4 = 12.02, p < 0.002; F2,4 = 15.9, p < 0.001), respectively. Medium temperature (60 °C) and long exposure time (5 min) significantly increased G. cordifolia germination percentage (F2,7 = 32.6, p < 0.001) while extreme temperatures (≥150 °C) at both (1 min) short and (5 min) long exposure time completely suppressed germination of G. cordifolia. Under high shade, while germination percentage was a third that of other treatments (F 2, 4 = 20.9, p = 0.008), mean germination took twice as long (F2, 4 = 17.9, p = 0.010) and shoot fresh biomass was reduced by half (F 2, 4 = 16.92, p = 0.004). Shoot and root dry biomass were reduced to more than a third under high shade, seedling height reduced to half but leaf chlorophyll content was not affected (F 2,4 = 6.3, p = 0.030; F 2,4 = 9.1, p = 0.020; F 2,4 = 18.3, p = 0.003; F 2,4 = 3.02, p = 0.120, respectively). We suggest using A. annua as a potential bio-herbicide and highlight considering fire and shade as suppressor tools to control G. cordifolia, but first include in-situ trials to assess their impacts to both native plants and animals
Potential Suppression Effects of Aqueous Extracts of Selected Plants on Growth of Carrot Weed (Parthenium hysterophorus L.) in Arusha, Tanzania
Get PDFThis research articles was published in Journals International Journal of Plant & Soil Science Volume 35, Issue 18, 2023This study investigates the potential suppression effects of aqueous extracts derived from selected
plants on the growth of carrot weed (Parthenium hysterophorus L.) in Arusha, Tanzania. The
research aimed to explore natural and sustainable methods for managing the proliferation of this
invasive weed species. Through a series of laboratory experiments, aqueous extracts were
prepared from specific plants namely amaranth (Amaranthus spinous L.), neem (Azadiratchta
indica L.) wheat millet (Sorghum bicolor), and marigold flower (Tagetes erictus L.). The extracts
were tested against carrot weed in the laboratory and pot experiment for their effectiveness in
inhibiting the germination and growth of carrot weed seeds under controlled conditions. Le
Mathematical model to study the impact of anthropogenic activities on forest biomass and forest-dependent wildlife population
Get PDFA project report submitted in International Journal of Dynamics and Control , Volume OnlineFirst – Jul 21, 2023This paper proposes and analyses a nonlinear mathematical model to study the impact of anthropogenic activities on forest biomass and forest-dependent wildlife populations using a system of differential equations. It is assumed that the growth of forest biomass, forest-dependent wildlife populations, and the human population follow logistic equations. The effect of forest biomass depletion on the survival of forest-dependent wildlife populations is investigated by introducing a function that denotes the dependence on forest biomass. The system’s behaviour near all ecologically acceptable equilibria is studied, and to confirm the analytical conclusions, a numerical simulation is performed. The model analysis shows that as forest biomass declines due to an increase in human population and its associated activities, the population of wildlife species also declines, and if no measures are taken, both forest biomass and the wildlife population may become extinct
Hydrogeochemical similarities and groundwater-surface water interactions for the karst hydrological system of northwest Rwanda
Get PDFThis research article was published in Arabian Journal of Geosciences, Volume 16, 2023.The groundwater of karst environments is vulnerable to pollution due to its heterogeneous nature and can be completely depleted due to its strong connection to surface water when predominantly driven by natural and anthropogenic factors. This particular landscape is the main source of drinking water in different parts of the world. Karst Hydrological of Rwanda hosts surface and groundwater resources. Moreover, groundwater is the main source of domestic water use in that area. The surface water is threatened by drying of crater lakes, changes of other lakes, and obstruction of sinkholes swallowing water from streams and runoff. Those problems may have direct and long-term impacts on groundwater recharge. The information on the hydrogeological characteristics of surface and groundwater, groundwater-surface water interaction, was limited. This study investigated the hydrogeochemical characteristics, similarities, and interactions of surface groundwater. To understand long-term impacts of surface water challenges on groundwater when are connected, statistical analyses and Piper diagram were used to achieve the objectives. The results showed a strong correlation among spring waters, reflecting similarity in the water origins. The Piper diagram classified the water as bicarbonate water (HCO−3
, Ca2+, Mg2+). The analysis of variance between surface water and groundwater did not show significant differences at the 0.05 level, which explains a relationship. The results showed a strong similarity and interaction between surface and groundwater. The findings of this study are important for water managers in consideration of future management since current problems on surface water may affect groundwater and community depending on that resource
Optimal control and cost effectiveness analysis of contamination associated with aflatoxins in maize kernels, livestock and humans
Get PDFA research article was submitted to Results in Control and Optimization Volume 13, December 2023Aflatoxin contamination poses a significant challenge in food safety and security as it affects both health of consumers and supply chains. Due to health impacts associated with aflatoxin contamination, countries have set standards and restrictions for importing food crops and animal feed, resulting in greater economic losses to farmers, transporters, and crop processors. Three controls, namely good farming practices, biological control and public education and awareness campaigns, have been mostly used in countries where aflatoxin contamination has occurred. Since resources are scarce, there is a need to find the optimal and cost-effective strategy to reduce the burden on farmers. This study aimed to find optimal and cost-effective control strategy to mitigated aflatoxin contamination in maize kernels, livestock and humans. A deterministic model was developed and analyzed for studying the impact of implementing three time dependent controls on the dynamics and control of aflatoxin contamination in maize kernels, livestock and humans. We use optimal control theory to find the necessary conditions for existence of the optimal controls and to determine the optimal strategy for controlling the aflatoxin contamination. We also carry out cost-effectiveness analysis through Incremental Cost Effective Ratio (ICER) to obtain the most effective strategy. Simulation results for the optimal control problem suggest that strategy which involve implementation of all controls performs well than other strategies in controlling the aflatoxin contamination in maize kernels, livestock and humans. Therefore, to control aflatoxin contamination initiatives should focus on good farming practices, biological control and public education and awareness campaigns
Infant and Young Child Feeding Practices and Mycotoxin Contamination of Complementary Food Ingredients in Kongwa District, Tanzania
Get PDFThis research article was published in the Current Developments in Nutrition Volume 7, Issue 2, February 2023Background: Inadequate infant and young child feeding (IYCF) practices in low income countries contribute to poor child growth and
development.
Objectives: To assess IYCF practices and mycotoxin contamination in complementary food ingredients across 2 seasons in Kongwa District,
Tanzania.
Methods: Early feeding practices in 115 rural households from 25 villages in Kongwa District, Dodoma region, Tanzania, were assessed. The
primary caregiver for the index child (6–18 mo of age) was interviewed using a structured dietary questionnaire at recruitment (October/
November 2017), and revisited 6 mo later. The questionnaire included questions on typical food consumption in the past 24 h. This study
reports 7 of the revised and new IYCF indicators, including minimum dietary diversity (MDD). Aflatoxins (AF) and fumonisins (FUM) were
analyzed in complementary food ingredients for pooled household samples to broadly establish patterns of contamination at the village
level.
Results: The MDD was not met for 80% of infants at recruitment (survey 1) as compared with 56% in survey 2 (P < 0.05). Changes in MDD
between the 2 surveys were dependent on season but not age. Maize was consumed by >90% of households in both surveys, whereas
groundnut was consumed by 44% and 64% of households in surveys 1 and 2, respectively. AF concentrations in maize and groundnuts were
found to be higher in survey 1 than in survey 2. Overall, AF exceeded the legal limit in 18% of maize and 61% of groundnut pooled samples
in both surveys. Maize was also contaminated with significant FUM concentrations.
Conclusions: Poor diets were common among children in Kongwa District. Reliance on maize and groundnuts exposes this vulnerable age
group to AF (also to FUM in maize). Inadequate diet and exposure to AF and FUM have separately been linked to linear growth retardation.
Low diet diversity and mycotoxins contamination are plausible causes for poor growth and development among infants in Central Tanzania.
Curr Dev Nutr 20XX;x:x
Characteristics of briquettes from plastic pyrolysis by-products
Get PDFThis research articles was published in Journals Mechanical Engineering
for Society and Industry Volume 3,2023Pyrolysis has been proven as a method to reduce plastic waste and produce useful products,
especially liquid fuels. However, plastic pyrolysis also produces gases and char as by-products
which are being investigated for useful products. Therefore, our present study aims to investigate
the char characteristics of plastic pyrolysis for further use as briquettes. Seven samples of char by-
products from the pyrolysis process of low-density polyethylene (LDPE) plastic at various reaction
temperatures and catalyst types were studied. The proximate test is used to determine the
properties of char such as moisture content, ash, volatile matter, and fixed carbon while the bomb
calorimeter is used to determine the calorific value. Briquettes are formed by mixing 4 grams of
char and 0.5-1 gram of binder (1% starch and 90% water). The briquettes were formed into solid
cylinders with a diameter of 1.75 cm and formed with a pressure of 10 kg/cm2. Furthermore, the
impact resistance index (IRI) was used to test the performance of the briquettes and showed an IRI
value between 100 and 200. However, of the seven char samples tested, three of them were
impossible to process into briquettes because they melted during the combustion tes
Short message service (SMS) based system for monitoring free chlorine concentration and Ph in the water reservoirs
Get PDFA Project Report Submitted in Partial Fulfilment of the Requirements for the Degree of Master of Science in Embedded and Mobile Systems of the Nelson Mandela African Institution of Science and TechnologyChlorine is the most common and affordable chemical reagent used for killing harmful micro organisms in the water to eliminate the spread of waterborne diseases such as cholera and
diarrhoea. According to World Health Organization, a free chlorine level within 0.5~1 mg/l
and a pH level within 6.5~8.5 is recommended for human consumption. It is essential to
monitor water quality parameters such as free chlorine in the water since a lower value will not
disinfect water efficiently while extreme values of free chlorine may affect the community’s
health. Zanzibar Water Authority (ZAWA) employs colorimetric approach to manually
measure free chlorine in the water reservoirs and submit the results into the kobocollect mobile
application. However, this approach is prone to human errors, ineffective and time consuming.
The objective of this current project was to develop a SMS-based system for monitoring free
chlorine concentration and pH in the water reservoirs. Extreme Programming (XP) agile
development methodology accompanied with V-Model were employed for developing and
testing of the proposed system. The developed system consists of hardware device and
dashboard for remote monitoring of water quality parameters such as free chlorine
concentration and pH. The hardware device sends sensor data and notification alerts as SMS.
The device is energy efficient since it uses SMS to send sensor data. The device can be
deployed in a noisy environment since it uses RS485 communication protocol to communicate
with the free chlorine sensor. The developed dashboard is used for remote monitoring of the
sensor data. The dashboard is user friendly and practical since it was designed with the end
users. The system was tested and validated by the end users to ensure all requirements were
met. The developed system has a potential capability to improve management of water
reservoirs by enhancing transparency, cooperation, and accountability among stakeholders
The role of textural properties and surface chemistry of activated carbon support in catalytic deoxygenation of triglycerides into renewable diesel
Get PDFThis research article was published in the Journals Catalysis Communications Volume 181,2023The textural properties and surface chemistry of activated carbon support are commonly known to have influ-
ence on the catalytic performance of catalysts. Many authors have assessed the effect of textural properties and
surface chemistry of activated carbon support in the deoxygenation of triglycerides. This review focuses on
reconciling literature on the role/relevance of textural properties and surface chemistry of activated carbon
support in deoxygenation of triglycerides into diesel-like hydrocarbons. It is revealed that different activated
carbon (AC) exhibit distinct effects on the catalytic behaviors of the supported catalyst. The degree of influence
of both textural properties and surface chemistry of AC support varies with the nature of the supported catalyst
Removal of fluoride and pathogens from water using the combined electrocoagulation-inline-electrolytic disinfection process
Get PDFThis research article was published in Water Supply Journal, Volume 23, Issue 7, 2023The consecutive removal of fluoride (defluoridation) and pathogens (disinfection) in drinking water through combined electrocoagulation-inline-electrolytic disinfection (EC–ECl2) process with aluminum and dimension-stable mixed oxide electrodes was reported in this study. Laboratory trials were conducted on the effects of flow rate, initial pH, current density, and supporting electrolytes for defluoridation and disinfection processes. The results have shown that with a flow rate of 10 L/h, initial pH of 6, the current density of 9.4 mA/cm2 (EC cell) and 3.1 mA/cm2 (ECl2 cell), supporting electrolyte concentration of 165 mg/L, and electrolysis time of 50 min, a defluoridation rate of 88% (initial concentration of 12.3 mg/L) and complete disinfection (initial fecal coliforms of 19,700 colony-forming units per 100 mL (CFU/100 mL)) can be reached. The final concentration of fluoride and pathogens in treated water was 1.44 mg/L and 0 CFU/100 mL, which are within the acceptable limit of the World Health Organization and the Tanzania Bureau of Standards of 1.5 mg/L and 0 CFU/100 mL, respectively. The EC–ECl2 system is a promising approach for consecutive defluoridation and disinfection of water to save millions from fluorosis and waterborne diseases. However, optimization potential with regard to energetic efficiency and system complexity was identified