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Comprehensive Analysis of Fuel Properties of Adansonia digitata Methyl Ester with the Influence of Nanoparticle Additives Extracted from an Agricultural Waste
Get PDFThis research article was published by Waste and Biomass Valorization Volume 13, 2022Purpose
This paper reports the results of experimental investigations on the influence of the addition of silica nanoparticles extracted from rice husk (an agricultural waste) on the major physicochemical properties of biodiesel derived from Adansonia digitata.
Methods
The physicochemical properties of the base fuel and the modified fuel formed by dispersing the nanoparticles by ultrasonic agitation were measured using ASTM and EN standard testing methods. The effects of manufactured silica nanoparticles on the fuel properties of Adansonia digitata methyl esters (ADME) that were produced by the transesterification process were investigated. Silica nanoparticles which were produced by the extraction process from rice husk were doped at the dosing levels of 400–1000 ppm. The produced silica was characterized by Thermogravimetry analysis (TGA), Barrett Emmett Teller (BET), Fourier transform infrared spectroscopy (FT-IR), Scanning electron microscope (SEM), X-ray fluorescence (XRF), and X-ray diffractometer (XRD) methods.
Results
The silica was found to have BET specific surface area, Barret-Joyner Halenda (BJH) pore diameter, and pore volume of 502.24 m2/g, 19.3 nm, and 0.761 cm3/g respectively. At 400 ppm and 800 ppm silica dosages, the oxidation induction period increased significantly from 5.2 h to a high of 10.3 h. These findings showed that ADME's oxidation stability had improved significantly to satisfy the ASTM D6751 and EN 14,214 standard limits of > 3 h and > 8 h, respectively. The kinematic viscosity of ADME dropped as the additive content increased, from 4.62 mm2/s for pure biodiesel to 2.21 mm2/s for 400 ppm. Furthermore, it was discovered that the largest increase in viscosity occurs at high doses of 600–1000 ppm. The flash point increased linearly as the amount of nanoparticle addition was increased. Higher flash point temperatures are desirable for improving engine performance and for safety issues. Also, results showed that cetane number (CN) increases from 60 to 64 simultaneously at the dosing level between 400 and 800 ppm and dropped to 63 at dosing levels beyond 800 ppm. The blending of Silica/Alumina showed the best improvement of CN of ADME about 33.6%. Commercial additive (Al2O3) showed an improvement of oxidation stability up to a dosing level of 800 ppm. Fuel blending of (B100 + SiO2), (B20 + SiO2), and (B20 + Al2O3) was also performed and the results showed that the oxidation induction period (OIP) increases from 3.8 to 10.3 h for (B100 + SiO2) blending up to dosing level of 800 ppm but decreases at 1000 ppm. However, blending (B20 + SiO2) showed significant improvement on OIP from 47.2% to 64.16% at 0 to 1000 ppm respectively but blending of B20 and Al2O3 showed the best improvement about 71.7% at 1000 ppm but slightly decreased at 600 ppm (15.7 h). Kinematic viscosity showed slight improvement (decrease by 32.6%) at 400 ppm, but increases at 600 ppm (4.16 mm2/s) for B20 + SiO2 fuel blending. However, at higher dosing level decreases by 3.85% up to 1000 ppm. Dosing of Al2O3 additive on B20 fuel blend displayed the improvement decreasing by 36.9% at 600 ppm but at higher dosage (1000 ppm) increases to 5.2 mm2/s for Al2O3.
Conclusion
Generally, from this study it has been observed that rice husk nano-particle is considered as a potential fuel-borne catalyst than the commercial one to improve the fuel properties, owing to their enhanced surface area to volume ratio probably due to its 3-dimensional tetrahedral coordination and covalent nature of silicon ato
Hydroxyapatite-activated seaweed biochar for enhanced remediation of fluoride contaminated soil at various pH ranges
Get PDFThis research article was published by Elsevier, 2023This study investigated the defluoridation efficiency of hydroxyapatite-activated seaweed (Eucheuma Cottonii) biochar (HSB) at various soil pH ranges (3–11) while monitoring the impact of contact time (30 min - 2.5 h), adsorbent dosage (0.1–0.5 g) as well as the initial fluoride concentration and compare its performance to its respective seaweed biochar (SB). Activation of SB with the hydroxyapatite lead to a shift in its point-zero-charge (pHPZC) from 6 to 7.4 broadening its defluoridation pH range from a solitary 5 to amid 3 through 11. The fluoride adsorption mechanism was found to follow both Langmuir (R2 = 0.956) and Freundlich (R2 = 0.942) isotherm models with a maximum defluoridation capacity of 3.03 mg/g equivalent to the defluoridation efficiency of 79%. This is accounted to the existence of soil ions, SB active sites, and the attached hydroxyapatite, as fluoride adsorption sites each exhibiting a dissimilar fluoride removal mechanism. Therefore, the HSB could be a promising adsorbent for fluoride removal in the fluoride contaminated agricultural soils of inclusive pH ranges
The Effect of Navier Slip and Skin Friction on Nanofluid Flow in a Porous Pipe
Get PDFThis research article was published by Engineering, Technology and Applied Science Research, 2022The flow of nanofluids through a porous medium is considered the optimum method for convective heat transfer. In this study, nanofluid flow in a porous pipe with Navier slip is investigated. Two water-based nanofluids, Copper (Cu) and alumina (Al2O3), were considered. The governing equation is presented and non-dimensionalization has been done for momentum and energy equations, initial and boundary conditions, skin friction, and Nusselt number. The governing system was simplified to ordinary differential equations, which were numerically solved and a mathematical model of nanofluid flow was formulated. The results, with regard to variations in various parameters such as temperature, velocity, skin friction, and Nusselt number, are presented graphically and discussed. It was found that the velocity during the flow decreases with the increase of the Navier slip
Evaluation of selected botanicals as insecticides against cabbage insect pests in Tanzania
Get PDFA Thesis Submitted in Fulfilment of the Requirements for the Degree of Doctor of Philosophy in Environmental Science and Engineering of the Nelson Mandela African Institution of Science and TechnologySynthetic pesticides are frequently and unwisely used to control cabbage insect pests by
smallholder farmers despite the environmental pollution and insect pests’ resistance
development. This work assessed the insecticidal efficacy of botanicals from Tephrosia vogelii,
Croton dichogamus and Syzygium aromaticum against cabbage insect pests in Northern
Tanzania. Firstly, larvicidal action of extracts against Crocidolomia binotalis and Plutella
xylostella larvae was assessed in the laboratory. Secondly, insecticidal and synergistic actions
of aqueous extracts against cabbage insect pests were assessed in field experiment. Lastly,
chemical compounds in S. aromaticum and in C. dichogamus were determined. The larvicidal
activities of extracts were assessed for mortality of ten larvae into 9 cm Petri-dishes for 24
hours of exposure. Chlorpyrifos and acetone were used as a positive and negative control,
respectively. The insecticidal efficacy of 10%, 5% and 1% w/v of T. vogelii, C. dichogamus
and S. aromaticum aqueous extracts and their mixture (2.5% and 5%) was assessed against
cabbage insect pests in the field. Chlorpyrifos was used as a positive control, and water and
water plus soap were used as negative controls. The GC-MS was used for compounds
identification in C. dichogamus and in S. aromaticum. Results from the study revealed that S.
aromaticum extract (16, 24 and 32 mg/mL), T. vogelii (24 and 32 mg/mL) and C. dichogamus
(32 mg/mL) gave 100 ± 0.0% mortality of C. binotalis larvae after 24 hours of exposure.
Moreover, S. aromaticum extract (8, 16, 24 and 32 mg/mL), T. vogelii (16, 24 and 32 mg/mL)
and C. dichogamus (32 mg/mL) gave 100 ± 0.0% mortality of P. xylostella larvae after 24
hours of exposure. The aqueous extracts from those plants significantly (P ≤ 0.05) lowered the
population of cabbage insect pests compared with negative controls. The 5% of aqueous extract
from mixed plants possessed significantly (P ≤ 0.01) lower population of cabbage insect pests
in both wet seasons compared with other concentrations. Then, it was followed by 10% of S.
aromaticum, C. dichogamus and T. vogelii aqueous extracts and 1% and 5% of aqueous extracts
of S. aromaticum, C. dichogamus and T. vogelii and 2.5% of aqueous extracts from the mixed
plants significantly lowered the population of insect pests compared with negative controls in
both seasons. The compounds identified in S. aromaticum, at higher percent were Eugenol
(52.66%); Eugenol acetate (20.46%) and β-caryophyllene (7.52%). Moreover, the compounds
identified in C. dichogamus at higher percent were 4,6-Bis (4-chloro-3-(trifluoromethyl)
phenoxy)-2-pyrimidinol (25.08%); Cholestan-6-en-3-ol (18.63%) and 1-Heptadecene (7.34%).
These compounds could be responsible for larvicidal and insecticidal activities against cabbage
ii
insect pests. Therefore, these plants can be recommended to be used by smallholder farmers
for cabbage insect pest control at higher concentrations and development of insecticides
Electrospun carbon nanofibers for use in the capacitive desalination of water
Get PDFThis research article was published by Elsevier, 2022, Volume 37, Issue 6Capacitive deionization (CDI) has rapidly become a promising approach for water desalination. The technique removes salt from water by applying an electric potential between two porous electrodes to cause adsorption of charged species on the electrode surfaces. The nature of CDI favors the use of nanostructured porous carbon materials with high specific surface areas and appropriate surface functional groups. Electrospun carbon nanofibers (CNFs) are ideal as they have a high specific surface area and surface characteristics for doping/grafting with electroactive agents. Compared with powdered materials, CNF electrodes are free-standing and don't require binders that increase resistivity. CNFs with an appropriate distribution of mesopores and micropores have better desalination performance. Compositing CNFs with faradaic materials improves ion storage by adding pseudocapacitance to the electric double layer capacitance. The use of electrospun CNFs as electrodes for CDI is summarized with emphasis on the major precursor materials used in their preparation and structure modification, and their relations to the performance in salt electrosorption
Serengeti’s futures: Exploring land use and land cover change scenarios to craft pathways for meeting conservation and development goals
Get PDFThis research article was published by Frontiers in Conservation Science, 2022Rapid land use transformations and increased climatic uncertainties challenge potential sustainable development pathways for communities and wildlife in regions with strong economic reliance on natural resources. In response to the complex causes and consequences of land use change, participatory scenario development approaches have emerged as key tools for analyzing drivers of change to help chart the future of socio-ecological systems. We assess stakeholder perspectives of land use and land cover change (LULCC) and integrate co-produced scenarios of future land cover change with spatial modeling to evaluate how future LULCC in the wider Serengeti ecosystem might align or diverge with the United Nations’ Sustainable Development Goals and the African Union’s Agenda 2063. Across the wider Serengeti ecosystem, population growth, infrastructural development, agricultural economy, and political will in support of climate change management strategies were perceived to be the key drivers of future LULCC. Under eight scenarios, declines in forest area as a proportion of total land area ranged from 0.1% to 4% in 2030 and from 0.1% to 6% in 2063, with the preservation of forest cover linked to the level of protection provided. Futures with well-demarcated protected areas, sound land use plans, and stable governance were highly desired. In contrast, futures with severe climate change impacts and encroached and degazetted protected areas were considered undesirable. Insights gained from our study are important for guiding pathways toward achieving sustainability goals while recognizing societies’ relationship with nature. The results highlight the usefulness of multi-stakeholder engagement, perspective sharing, and consensus building toward shared socio-ecological goals
The Potential of Valorized Sisal Decorticated Waste in Rearing of Black Soldier Fly
Get PDFThis research article was published by MDPI, 2022The use of sisal decorticated waste (SDW) for various applications is limited due to its high acidic content. This is the first study of its kind regarding the use of SDW as a substrate for the growth of the black soldier fly (BSF). Pre-treatment was a necessary and challenging step performed on the waste to meet the minimum requirements for the rearing of BSF. The SDW was sun dried, sieved, and decomposited and neutralized to form the final products that were used for the rearing of BSF. The resultant waste had fourteen (14) elements; the essential elemental form results were Ca, P, K, Mn, Fe, Cu, and Zn at varying levels, which are all essential for animal growth. The SDW contained 10 ± 0.01 percent of crude protein, 11 ± 0.02 moisture and energy (1615 kcal/g of sisal decorticated waste). The sun dried BSF larvae were reared on SDW that contained 53 ± 0.005 percent of crude protein, 4 ± 0.01 percent of crude fat, a moisture content of (10 ± 0.1)%, carbohydrate percent of (43 ± 0.01)%, and ash percent of (37 ± 0.08). When rearing was finished, 3000 g of dried pre-treated waste yielded more wet BSF larvae, (336 ± 41.3) g, compared to 3000 g of fruit waste, which yielded (244 ± 4.16) g of wet BSF larvae. Therefore, based on this study, SDW is a promising potential feed for rearing BSF because it had a better reduction of the waste by 52%. Furthermore, the harvested BSF larvae contained sufficient nutritional value to feed poultry and fish
Early-Warning Dropout Visualization Tool for Secondary Schools: Using Machine Learning, QR Code, GIS and Mobile Application Techniques
Get PDFThis research article was published by the International Journal of Advanced Computer Science and Applications, Volume 13, Issue 11, 2022.: Investment in education through the provision of secondary school to the community is geared to develop human capital in Tanzania. However, these investments have been hampered by unacceptable higher rates of school dropouts, which seriously affect female students, since most schools do not have effective mechanisms for quality data management for immediate and effective decision making. Therefore, this study aims to solve the problem of data management from the school level in order to assist higher levels to receive appropriate and effective data on time through the use of emerging technologies such as machine learning, QR codes, and mobile application. To implement this solution, the study has explored the predictors of school dropout using a mixed approach with questionnaires and interview discussion. 600 participants participated in problem identification in the Arusha region. Through the use of design science research methodology, Unified Modeling Language, MYSQL, QR codes and mobile application techniques were integrated with Support Vector Machine to develop the proposed solution. Finally, the evaluation process considered 100 participants, and the results showed that an average of 89% of participants provided positive feedback on the functionalities of the developed tool to prevent dropouts in secondary schools in Africa at large
Giraffe foraging ecology in the Tarangire Manyara ecosystem, Tanzania
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 TechnologyManagement of rangelands requires knowledge of forage species that are preferred or avoided by
wildlife and livestock. The recent and rapid transformation of habitat by humans has led to
increased concerns about the proper management of rangelands. In East African savanna
ecosystems, the expansion of woody vegetation into previously open grasslands has led some
rangeland managers to advocate for the active removal of native bushes to maintain grazing
lawns in African savanna ecosystems. However, little is known about how browsing herbivores
might benefit from the ingrowth of woody vegetation. Diet selection by the Masai giraffe
(Giraffa camelopardalis tippelskirchi) was quantified in the Tarangire Manyara Ecosystem of
Tanzania. Instantaneous scan sampling was used to quantify foraged woody plant species and
compare those data with proportions of available woody plant species at two different spatial
scales during a wet and dry season and between areas of different protection statuses. Study
results showed that giraffes demonstrated strong selection towards some woody plant species
while avoiding others, both at the local and the landscape scale. Giraffes preferentially used more
forage species in less protected areas (8 forage species) than in a fully protected area (only 1
species). At both spatial scales, giraffes significantly preferred the shrub Dichrostachys cinerea,
a species that livestock managers have classified as encroacher species needing removal. This
preference was visible in the wet and dry seasons. The results of this study suggest that browsing
wildlife species such as giraffes may be adversely affected by the removal of D. cinerea from
rangelands and that managing for grazing livestock only could negatively impact browsing
wildlife on mixed-use lands
Modeling and optimization of independent factors influencing lead(II) biosorption from aqueous systems: A statistical approach
Get PDFThis research article was published by Elsevier, 2022Lead, [Pb(II)] is a major hazardous contaminant that exists in the soil, surface, and groundwater as a result of human activities. It is carcinogenic in nature and causes damage to the liver, kidney, and bones as well as the digestive, respiratory, and immune systems. As a result, the main purpose of this study was to prepare and employ modified powdered peanut shells as a biosorbent in the decontamination of lead(II) ions from aqueous solutions. The removal of lead(II) onto the biosorbent was modeled and optimized using the response surface methodology and the effects of three biosorption variables on two response variables were investigated using the central composite design of the response surface methodology. The optimization of lead(II) removal by the biosorbent shows that contact time, pH, and initial concentration had a significant influence on the removal efficiency and biosorption capacity of lead(II). This was shown by the response surface methodology where the interaction among the independent variables studied improved the biosorption of lead(II). Applying the central composite design, the optimized contact time ( min), pH (), and initial concentration ( mg/L) gave a removal of and biosorption capacity of mg/g of lead(II) with the desirability of . The study revealed that the modified powdered peanut shells, a low-cost biosorbent was efficient in decontaminating lead(II) ions in the aqueous solutions. However, the biosorption process optimization was dependent on contact time, pH, and initial lead(II) concentration. The study recommends that the untreated form of the peanut shells should be used and the results compared with the present study