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This research investigates the design principle for metal organic frameworks (MOF) deposited composite membranes for nanofiltration using functionalized/modified UiO-66 (UiO stands for University of Oslo) nanoparticles for the purpose of exploring the importance of functional groups around the nanopores. The nanoparticles were synthesized using water as modulator and characterized by XRD, FTIR, TEM, BET and TGA. The XRD major (sharp) peaks indicated the crystallin ity of the nanoparticles whilst the minor peaks at 2θ = 6° originated from reo-nanoregions. The intensity of the reo peak was correlated with the concentration of missing clusters/linkers, cluster defects in the samples and become prominent as small amount of modulator was added. The particle sizes were found to be in the range of 150‐60 nm, 160-60 nm for UiO 66-NH2, UiO-66-CH3 frameworks respectively. The dependence of the particle size on the amount of water demonstrated its role to accelerate the formation of crystal nuclei. The BET surface area and pore volume were found to be in the range of 800-1000 m2/g and 0.37-0.44 m3/g without clear tendency on the framework type. The pore size distribution was sharp ly concentrated in the range of 0.7-0.8 nm whilst the weight loss due to ligand decomposition was found to have changed by the water addition irrespective of the ligand functionalization. The functionalized UiO-66 formed polycrystalline, de fective nanoparticles and gave high flux compared to non-functionalized type and was found to be superior for leakage tolerance irrespective of the frameworks. However, the tendency to leakage was found to be greater for smaller particle size. Its polycrystalline nature played an important role whilst the modification affects the chemoselectivity and permea tion. The pore engineering geared towards changing the chemical environment played significant effects and unlock infor mation for proper understanding of the role of chemical environment in UiO-66-CH3 and UiO-66-NH2 nanocomposite membranes.

Abstract

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Nigeria is the largest producer of cassava in the world and the peel accounts for between 5 -15% of the tuber. Cassava peel is often left unattended in the country, making it a source of methane gas which is one of the culprits of global warming. Agricultural residues are good sources of renewable energy. This study investigated the potential of electricity and heat generation from cassava peels. The dried peel was ground and used for proximate analysis according to ASTM D 5142-04 procedure, from where moisture, ash, Volatile Matter (VM) and the Fixed Carbon (FC) contents were determined. The Higher Heating Value (HHV) of cassava was calculated using the FC. Performance of four plants tagged A, B, C and D were simulated using thermodynamics equations. Plant A was simulated as a boiler-steam turbine combination, Plant B, gasifier-boiler steam turbine, Plant C, gasifier-gas turbine and Plant D, gasifier-internal combustion engine combination. Parameters investigated were power output, heat output, annual electrical energy generation per peel mass. Results gave the moisture, ash, VM and FC contents as 6.53, 3.78, 89.57 and 6.65 % respectively while the HHV was determined to be 15.422 MJ/kg. Estimated power output was 2.51 x 105, 1.78 x 105, 1.39 x 106 and 1.26b x 106 kW for Plants A, B, C and D respectively. In a like manner, the heat output is1.02 x 107, 7.24 x 106, 8.84 x 106 and 1.06 x 107 MJ/h. Annual electrical energy output was determined to be 9.03 x 108, 6.42 x 108, 5.00 x 109 and 4.52 x 109 kWh and the electrical energy gener ation per cassava peel consumption was 0.202, 0.144, 1.121 and 1.009 kWh/kg for Plants A, B, C and D respectively. Cas sava peel possesses good potential for heat and electrical energy co-generation in Nigeria.

Abstract

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In this study, a Potentiostat was developed for teaching and research purposes because Potentiostats are expensive equip ment and are of high importance in corrosion monitoring due to its various applications. The fabrication of this potenti ostat entailed the use of electronic devices and components, including operational amplifiers in the control circuit. A mi crocontroller was used to send data from the circuit to the computer system, and the results obtained were visualized in real-time on a software application, made with Python programming language and Tkinter (a library for desktop applica tion development) installed on the computer system. The software application uses linear regression (an algorithm in ma chine learning) to calculate the slope of the anodic and cathodic curve, which are used to obtain the corrosion rate. This study proffers solution to some of the shortcomings of locally-made potentiostats, which are unable to plot corrosion data in real-time and determine anodic and cathodic slopes needed to obtain the corrosion rate, while still being affordable for teaching and research purposes.

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This study presents the formulation and development of silicon nano-composite based conductive ink for possible screen printing of selected electronic devices. An XRD technique was employed to characterize and the result analysis showed that the particles were nano- sized Silicon nano-composite based conductive inks were formulated and developed from milled silicon nano-particle which served as the dispersed phase or filler materials and dispersed in styrene acrylic and distilled water. A modified screen-printing method was adopted for the deposition of formulated inks on ceramic substrates. Current-voltage characteristics of the printed electronic devices were obtained and employed to determine the nature of interface, behavioural responses upon voltage application, resistivity, effect mass of charge carrier, and barrier height of the con ductive inks. The study revealed that the mass fraction of silicon nano-particle and styrene acrylic in ink formulation E meets the needs of additive manufacturing technology of selected electronic devices.