2647 research outputs found
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Synthesis and characterization of aminofunctionalized chitosan-silica nanocomposite for the removal of Cu2+ from waste water
Full text linkThis research article was published by Discover Materials Volume 5, February 2025This study presents the synthesis and characterization of an aminofunctionalized chitosan-silica nanocomposite using the polymer melt intercalation technique. Chitosan, a biopolymer with inherent biocompatibility and antimicrobial properties, was functionalized with amino groups to enhance its reactivity and potential applications. Silica nanoparticles were incorporated as the reinforcing agent, providing improved thermal and mechanical stability. The polymer melt intercalation method facilitated uniform dispersion of silica within the chitosan matrix, overcoming common agglomeration challenges. The synthesized nanocomposite was thoroughly characterized using Fourier Transform Infrared Spectroscopy (FTIR) to confirm chemical modifications, Scanning Electron Microscopy (SEM) to observe morphological features. X-ray Diffraction (XRD) was used to evaluate structural integrity and dispersion of silica within the polymer matrix. The results demonstrated successful aminofunctionalization and homogeneous silica distribution, leading to a significant improvement in mechanical strength, thermal resistance, and biodegradability. These findings suggest that 0.5 mg of the aminofunctionalized chitosan-silica nanocomposites removed 98% of Cu2+ from contaminated water at an extended pH range of 4 to 6. In addition, the nanocomposite exhibited a significant increase in adsorption capacity at a sample dose ranging from 10 to 50 mg in 50 ml of the model solutions
Adsorption of phenol and methylene blue contaminants onto high-performance catalytic activated carbon from biomass residues
Full text linkThis research article was published by Heliyon Volume 11, January 2025Organic contaminants from wastewater toxicity to the environment has increased during the last few decades and, therefore, there is an urgent need to decontaminate wastewater prior to disposal. This study aimed to create a high surface area catalytic activated carbon (AC) under same carbonization conditions for phenol and methylene blue (organic wastewater) decontamination. Moringa oleifera husk (MH), sesame husk (SH), and baobab husk (BH) were used to prepare activated carbon for the removal of methylene blue (MB) and phenol (Ph). After characterization of the adsorbent, the BET surface areas of the M. oleifera husk activated carbon (MHC), sesame husk activated carbon (SHC), and baobab husk activated carbon (BHC) were 1902.30 m2/g, 1115.90 m2/g, and 1412.40 m2/g, respectively. Mono-adsorption and binary-adsorption systems were studied for Ph and MB adsorption. Furthermore, the effect of initial organic waste concentration, contact time, pH, temperature and AC dosage, on adsorption capacity were studied. The mono adsorption system isotherms and kinetics studies used to analyze Phenol and MB adsorption best fitted Langmuir and pseudo-second-order models. The Freundlich isotherm and pseudo-second-order model best fitted the experimental data for the binary-adsorption system. The high maximum adsorption capacities of organic waste for the single and binary systems were 352.25–855.96 mg/g and 348.90–456.39 mg/g, respectively. The results showed that the high surface activated carbon produced had the potential to adsorb high concentrations of MB and Phenol contaminants
Modelling and optimization of different pozzolanic materials in the durability of cement composite by central composite design
No full textThis research article was published by Applications in Engineering Science, 2025The production of Ordinary Portland Cement (OPC) requires high temperatures and significant energy consumption, leading to environmental pollution and posing challenges to the sustainability of green cementing materials. To address this, numerous researchers have explored replacing cement with various supplementary cementitious materials, such as blast furnace slag, active limestone, and bentonite, in concrete or mortar. However, optimizing the combined use of these materials to achieve maximum durability in mortar remains a novel area of study. This research models and optimizes the effects of replacing OPC with blast furnace slag, active limestone, and bentonite in mortar using the central composite design method. The findings reveal that increasing the content of bentonite along with either blast furnace slag or limestone from 0% to 20% significantly minimizes strength degradation due to sulfuric acid exposure, improves heat resistance, and lowers water absorption at 28 days. The optimal substitution levels were found to be 20% for both blast furnace slag and limestone, and 18.54% for bentonite. The optumal result reduced damage from sulfate attack by 33.4%, strength loss under high temperatures by 69.04%, and water absorption by 98.58% when compared to the control sample. These outcomes were validated experimentally with a 95% confidence level. Overall, incorporating these SCMs not only improves the durability of mortar but also supports environmental sustainability by reducing CO₂ emissions due to OPC production
Eco-friendly catalyst design: Transforming volcanic lava ashes into sustainable synthesis of glycerol carbonate from glycerol in one pot solvent-free route
No full textThis research article was published by Journal of Environmental Chemical Engineering Volume 13, 2025Volcanic lava ash (VLA), a natural waste from nature’s geological activities was used as a raw material for the first time to produce a series of heterogeneous catalysts via facile calcination from 300 to 900 °C. The heterogeneous catalysts were used to synthesize glycerol carbonate (GC) from the transesterification reaction of glycerol (GL) and dimethyl carbonate (DMC). The structural-morphological-crystalline characterization revealed dominant active sites Mg1.04 (SiO3), CK2O3, KAlSiO4, Na3PO4, NaAlO2 and CaO with some silicates and organic carbon, which provided support and stabilizing effects for the alkaline oxides and mixed oxides. The calcination facilitated phase transformation from lower basicity hydroxides and carbonates to higher basicity oxides. The VLA-800 °C catalyst produced the best GC yield and GL conversion reaching 91 ± 1 % and 97 ± 3 %, respectively, at reaction conditions 75 °C, GL: DMC of 1:3, and catalyst loading of 5 wt% under 90 min reaction time. The catalyst maintained (74 ± 1 %) GC yield after the 6th reuse cycle with leaching of active sites and masking by organic matter as the main causes of the progressive loss in catalytic activity
Advances in botanical-based nanoformulations for sustainable cotton insect pest management in developing countries
No full textThis research article was published in the Journal of Frontiers in Agronomy, Volume 7, 2025Cotton is an important crop that significantly contributes to the economies of
developing countries, providing income for farmers and driving economic
growth in rural areas. However, cotton production in developing countries
faces significant challenges due to insect pest infestations. The main impacts
include yield losses and increased reliance on synthetic pesticides. Recent
advances in pest management are constrained by the use of chemical
pesticides that are harmful to the environment and less efficacy and stability of
bio-based formulations, especially plant-based. Challenges are more significant
in the developing countries where low technology, and reliance on synthetic
adulterated products are experienced. To evaluate advances in sustainable pest
management, 760 articles were collated and screened. A total of 39 qualified
peer-reviewed articles were used to evaluate current research advancements in
botanical nanoformulations for sustainable cotton insect pest management in
developing countries and examined their efficacy on key cotton insect pests,
formulation techniques, mode of action and environmental impact while
identifying challenges such as nanoparticle stability and scalability. Results
showed that botanical nanoformulations such as silver and zinc nanoparticles,
nano-emulsions, and polymeric carriers enhance efficacy, stability, and
environmental sustainability. About 85% of the studies were laboratory-based
experiments, with only 15% being semi-field and/or field trials. Findings indicate
that botanical nanoformulations are viable alternative for manging cotton insect
pest management. However more researches are needed to optimize their
stability and efficacy in real-world cotton insect pest management in
developing countries context
Swahili questions and answers dataset for aflatoxin knowledge domain
No full textThis research article was published by Data in Brief Volume 60, 2025Aflatoxin contamination is a challenge facing food security, health, and trade in Tanzania and other parts of the world. This contamination affects maize, groundnuts, and other crops and animal products. Once contamination occurs, the contaminated crops and animal products become toxic causing illness or death to humans and animals who consume them. Lack of awareness and knowledge of the contamination is seen to be one of the reasons for its continued occurrence. Various awareness-creation and knowledge-sharing techniques have been used but the situation is still not appealing. For this case, the use of a Natural Language Processing (NLP) chatbot in sharing aflatoxin knowledge is proposed. This is because NLP chatbots have been successful in knowledge sharing in various contexts. This data article presents a Swahili text-based aflatoxin knowledge questions and answers dataset. Data were collected through 7 focus group discussion (FGD) sessions conducted in Arusha, Dodoma, Mtwara, Tabora, Morogoro, and Iringa regions in Tanzania. Respondents for the study were farmers, traders, and consumers of maize and groundnuts. The collected data were processed and analyzed using R qualitative data analysis tool. This allowed the identification of 6 themes with respective questions under each theme. The questions were shared with experts through 9 interview sessions and the experts gave answers to the questions. The set of questions and answers were then translated into Swahili language using google translate and manual verification. Finally, an aflatoxin knowledge dataset containing 221 paired questions and answers organized into 6 knowledge areas Swahili dataset was developed. With this dataset, an NLP-based chatbot that uses Swahili language can be developed. This will be beneficial to farmers, traders, consumers, researchers, and policymakers. They can use it to learn more about aflatoxin and be able to make informed decisions. Moreover, the dataset can be adopted and modified to create NLP chatbots that can share aflatoxin knowledge in other languages apart from Swahili. The dataset also contributes to the availability of Swahili language datasets
Computational analysis of Urolithin A as a potential compound for anti-inflammatory, antioxidant, and neurodegenerative pathways
No full textThis research article was published by Free Radical Biology and Medicine, Volume 227, 1 February 2025Urolithin A, an active precursor derived from the metabolism of ellagitanins in rats and humans, is known for its potential health benefits, including stimulating mitophagy and promoting muscular skeletal function. While experimental studies have demonstrated Urolithin A's potential to enhance cellular health, the detailed molecular interactions through which Urolithin A exerts its effects are not fully elucidated. In this study, we investigated the anti-inflammatory, antioxidation and neuroprotective abilities of Urolithin A in selected targets using molecular docking and molecular dynamics simulation methods. Molecular docking studies revealed the strong affinity for receptors involved in inflammation activities, including human p38 MAP kinase (4DLI) with −10.1 kcal/mol interacting with SER252, LYS249, and ASP294 residues. The binding energy in the 5KIR target was −8.6 kcal/mol, interacting with GLN203 through hydrogen bond, and lastly, 1A9U with an affinity of −6.8 with no hydrogen bond formed with Urolithin A and interacts with van der Waals interactions. In oxidant targets, the influence of Urolithin was observed in 1OG5 with −7.9 kcal/mol interacting with GLN185, PHE447. For the 1M17 target, the binding affinity was −7.7 kcal/mol interacting with THR95 residue and 1ZXM target at −7.4 kcal/mol interacting with TYR36, TYR216, and LEU234 residues. The neuroprotective ability of urolithin A was observed in selected targets for acetylcholinesterase; the binding energy was −9.7 kcal/mol interacting with van der Waals and π interactions; for the 1GQR target, the binding energy was −9.9 kcal/mol interacting with van der Waals and π interactions and for β-amylase (1iyt) the binding energy was −5.5 forming hydrogen bond with SER8, GLN15 residues. Molecular Dynamics simulations at 100 ns of Urolithin A compared with reference 4DLI. The Urolithin A-4DLI complex exhibited greater stability than the reference receptor, as confirmed by RMSD, RMSF, Radius of Gyration, Hydrogen bond, and SASA analyses
Dust exposure and its health implications to miners in Mererani artisanal and small-scale mining industry
Full text linkThis research article was published by International Journal of Environmental Analytical Chemistry, 2025This study aimed to identify and quantify the total dust exposure to underground miners in Mererani, Tanzania, and its composition to generate evidence for informed decision- and policy-making. The Analytical Air Monitoring System (AMS) was used for dust collection, and analysis was conducted gravimetrically. The dust composition was analysed using Inductively Coupled Plasma Optical Emission Spectroscopy. The results showed significant variation in dust exposure levels across different mining zones, with miners inhaling up to 1859 mg of dust over an 8-hour period in drilling zones (DZ), 797 mg in loading zones (LZ), and 382 mg in resting zones (RZ). The mean value of dust exposure was significantly different, with a p-value of <0.05. Miners had higher levels of heavy metal and silica than those from unmined sites, with chromium being the most dominant element across all samples. Cumulative exposure to dust over time is linked to long-term respiratory impairment and serious health conditions such as lung cancer. These findings highlight the need for intervention, including education on dust hazards, provision of personal protective equipment (PPE), and enforcement of safety standards to safeguard miners’ health. Addressing these issues is critical to promoting policy reforms and sustainable mining practices in Mererani and similar communities
Impacts of Nonlinear Loads on the Power Quality of Solar Microgrids and Proposed Mitigation Strategies
No full textThis research article was published by Energy Science & Engineering, 2025The integration of solar energy into microgrids poses significant challenges in maintaining power quality due to the variable nature of solar generation and the presence of nonlinear loads such as uninterruptible power supplies (UPS), variable frequency drives (VFDs), rectifiers, and power electronic components. Active power filters are often used to mitigate harmonics; however, these solutions are complex due to the use of control techniques like the synchronous reference frame and can introduce additional harmonic currents during compensation within electrical systems. This study investigates the effects of different nonlinear loads on the power quality of solar microgrids and explores the reduction of harmonics from VFDs through the application of passive harmonic filters (PHFs). The objective was achieved by measuring harmonics generated by nonlinear loads and simulating a modeled VFD circuit using MATLAB/Simulink R2021b software, considering the demand side. Analysis of current harmonics measurements at the point of common coupling revealed that the total harmonic current distortion (THCD) for UPS, VFDs, and rectifiers was 20.64%, 42.82%, and 22.59%, respectively, while the total harmonic voltage distortion (THVD) for UPS, VFDs, and rectifiers was 27.83%, 31.55%, and 29.16%, respectively. Moreover, the total losses caused by harmonic distortion from these nonlinear loads is 860 Watts. Among these loads, VFDs were the dominant source of harmonics. Therefore, the application of passive harmonic filters (PHFs) was proposed to minimize harmonics in solar microgrids, adhering to the standards set by the Institution of Electrical and Electronics Engineers (IEEE) and the International Electro‐Technical Commission (IEC). Simulation of the VFD revealed that the THCD was reduced by 89.4% and the THVD was minimized by 89.9% due to the connection of passive harmonic filters. These filters have the capability to minimize harmonics to within IEEE 519 standard limit
Strategies for implementing research data management (RDM) services in Tanzania's higher education institutions (HEIs)
No full textThis research article was published in the journal of Collection and curation, Volume 44, Issue 2, 2025Purpose
This study aims to explore the strategies for implementing research data management (RDM) services in Tanzania’s higher education institutions (HEIs).
Design/methodology/approach
The study drew upon the technology, organization, people and environment (TOPE) framework. Using a qualitative case study approach, data was collected through semistructured interviews with librarians, lecturers, information and communication technologies (ICT) and research and innovation staff. Data was thematically analyzed.
Findings
Numerous participants recognized the importance of RDM services, such as creating data management plans, enhancing the retrieval and reuse of research data and offering support for data curation and preservation. The study also identified organizational support, including developing policies and guidelines, providing financial assistance and ensuring data security. Furthermore, the study highlighted the importance of ICT infrastructure, including servers, software and hardware. A lack of ICT infrastructure and limited skills and knowledge among those responsible for implementing RDM services were among the challenges identified.
Research limitations/implications
This study used the TOPE framework, along with relevant literature, to guide the formulation of research objectives and questions. While the TOPE framework offers a comprehensive view through its four dimensions, there is a need to integrate additional models, such as data curation, to achieve a more holistic understanding.
Practical implications
This study provides valuable insights into strategies for implementing RDM services in HEIs. It highlights the importance of professional development for stakeholders, enabling them to develop and enforce effective strategies supporting a data-driven research agenda.
Originality/value
This study contributes original insights by outlining the necessary strategies for HEIs to consider when implementing RDM services. The study adds value to understanding effective RDM implementation requirements in an academic setting by identifying various strategies for developing RDM activities