http://repository.must.ac.ke/handle/123456789/19 2026-04-10T10:47:45Z http://repository.must.ac.ke/handle/123456789/1575 Equilibrium and Thermodynamic Studies on Biosorption of Pb (II) and Cd (II) Ions from Wastewater onto Clay Cellulose Nanocomposite Adsorbent Kinoti, Ismael Kithinji; Marangu, Joseph Mwiti; M'thiruaine, Cyprian he adsorption of lead (II) and cadmium (II) ions from aqueous solutions by novel water hyacinth-based cellulose clay nanocomposite were studied and their adsorption performance established using the Langmuir, Dubinim-Radushkevich, Temkin and Freundlich isotherm models. The water hyacinth-based cellulose clay nanocomposite (CCNC) was synthesized by solution blending method, with poly vinyl alcohol solution as the dispersion medium. Characterization of the CCNC was done using Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM). According to the adsorption studies, Pb (II) ions were adsorbed by the CCNC material through a heterogeneous process, whereas Cd (II) was adsorbed through both monolayer and heterogeneous processes. While Freundlich and D-R isotherms were the best at explaining the adsorption of Pb (II), Langmuir, Temkin, and Freundlich isotherm models were most effective at explaining the adsorption of Cd (II). The adsorption process was exothermic, according to thermodynamic analyses. The pH value of 4, the adsorbent dose of 0.8g per 100 ml of contaminated water, the temperature of 25 °C, and the contact period of 30 to 120 minutes were shown to be the most effective conditions for the adsorption of Pb (II) and Cd (II) ions from wastewater. The highest percentage metal ion removal was observed to be 99.6 % (Cd2+) and 99.9 % (Pb2+). 2024-01-01T00:00:00Z http://repository.must.ac.ke/handle/123456789/1554 Rheology of Clay-Based Cement Systems–A Review Masolia, Cleah Minayo; Kinoti, Ismael Kithinji; Mureti, Brian; Mwangi, Joseph Kaigai; Mutua, John; M’thiruaine, Cyprian Muturia; Marangu, Joseph Mwiti Cement is the world’s second-most consumed material and its production contributes substantially to global CO2 emissions. Replacing clinker with supplementary cementitious materials (SCMs), such as calcined clay, can lower the carbon footprint. Calcined clay, available in abundance and processed at 800–900C, can replace up to 50% of clinker. This review critically examines the rheological behavior of clay-based cement systems, focusing on their yield stress (YS), viscosity, and thixotropy. Compared to OPC, clay-based systems show a 20–70% increase in YS with >30% calcined clay, and nano-metakaolin enhances thixotropy by up to 60%. Herschel–Bulkley’s model (R2 > 0.98) describes best their non-linear shear-thinning behavior. While shear-thinning improves pumpability in applications like 3D printing, it may reduce formwork stability. The review explores how SCM type, water-to-cement ratio, and superplasticizer dosage affect flowability. It uniquely links rheological properties to practical engineering demands, aiding in the development of high-performance, sustainable cement systems. 2025-07-01T00:00:00Z http://repository.must.ac.ke/handle/123456789/1047 Robotic Medical Services and the Future of Healthcare in Kenya Onyango, Joab; Jepkogei, Barsoget With the Kenyan healthcare affected by challenges of availability, accessibility and affordability, there is a pressing need to examine how to adopt robotic medicine as a permanent solution. This study aimed to assess the adoption of robotic medical services (4IR technology) and the future of Kenyan healthcare. The specific objectives were to identify drivers of change in accelerating robotic medicine adoption and provide policy recommendations. The study employed a scenario planning approach methodology, focusing on four steps: defining the scenario question and time horizon, identifying drivers of change, and developing and applying scenarios, guided by diffusion innovation theory. The twelve key drivers of change are societal and expert acceptance of robotic medicine, compatibility with existing infrastructure, robustness of data and internet for AI, investment costs, national healthcare budget, recyclability and environmental impact of medical waste, legislative frameworks, global political collaboration, and AI-related intellectual property, liability, and ethical issues such as patient data privacy, transparency, and bias. The robustness of data and internet for AI and the level of societal acceptance were identified as driving forces. The plausible future scenarios, i.e. Successful Adoption, Low Adoption, Chaotic Change and Rejection of the Adoption were identified. The main opportunities were identified as rapid AI technological developments, medical tourism, and robotic medical innovations. Finally, the critical challenges in the plausible future were found to be regulatory uncertainty, ethical concerns, data privacy and public misconceptions from social acceptance levels. The study recommended the government to invest in AI infrastructure, develop an AI usage framework, create an enabling environment that encourages robotic medicine adoption, establish stringent data usage regulations, foster societal acceptance through targeted community engagement and education initiatives to robotic medicine adoption 2024-01-01T00:00:00Z http://repository.must.ac.ke/handle/123456789/1038 Evaluation of Kunkur Fines for Utilization in the Production of Ternary Blended Cements Mutai, Victor Kiptoo; Marangu, Joseph Mwiti; M’Thiruaine, Cyprian Muturia; Valentini, Luca Ternary blended cements, such as limestone calcined clay cement (LC3), represent a type of strategic binder for the mitigation of environmental impacts associated with cement production. These are estimated to reduce CO2 emissions by about 40% compared to ordinary Portland cement (OPC). In this paper, we explore the possibility of producing such ternary blends by utilizing secondary raw materials that may be locally available. Specifically, the primary limestone that is commonly used in LC3 is herein substituted with quarry dust obtained by sourcing “kunkur”, a carbonaterich sedimentary rock (also known as caliche) that can be locally utilized for the production of ordinary OPC clinker. To optimize the blending proportions of ternary cement consisting of OPC, calcined clay, and kunkur fines, a “design of experiment” (DoE) approach was implemented with the goal of exploring the possibility of reducing the amount of the OPC fraction to values lower than 50%. The properties of the formulated blends were assessed by a combination of techniques that comprise mechanical strength testing, XRD time-dependent quantitative phase analysis, and SEM–EDS microstructural and microchemical analyses. The results suggest that ternary blended cement based on kunkur fines forms hydration products, such as hemicarboaluminates, which are also observed in LC3. This shows that such waste materials can potentially be used in sustainable cement blends; however, the presence of kaolinite in the kunkur fines seems to affect their strength development when compared to both OPC and conventional LC3. 2023-11-30T00:00:00Z