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51	Graphol and vanadia-linkedzink-doped lithium manganese silicate nanoarchitectonic platforms for supercapatteries Ndipingwi, Miranda Mengwi January 2020 (has links) Philosophiae Doctor - PhD / Energy storage technologies are rapidly being developed due to the increased awareness of global warming and growing reliance of society on renewable energy sources. Among various electrochemical energy storage technologies, high power supercapacitors and lithium ion batteries with excellent energy density stand out in terms of their flexibility and scalability. However, supercapacitors are handicapped by low energy density and batteries lag behind in power. Supercapatteries have emerged as hybrid devices which synergize the merits of supercapacitors and batteries with the likelihood of becoming the ultimate power sources for multi-function electronic equipment and electric/hybrid vehicles in the future. But the need for new and advanced electrodes is key to enhancing the performance of supercapatteries. Leading-edge technologies in material design such as nanoarchitectonics become very relevant in this regard. This work involves the preparation of vanadium pentoxide (V2O5), pristine and zinc doped lithium manganese silicate (Li2MnSiO4) nanoarchitectures as well as their composites with hydroxylated graphene (G-ol) and carbon nanotubes (CNT). / 2023-12-01 Aqueous electrolytes Battery-supercapacitor hybrids Carbon nanotubes Composite nanoarchitectures Capacitance retention Hydroxylated graphene Lithium manganese silicate Mechanochemical reactions Nanoarchitectonics Specific capacitance Specific energy Specific power Supercapatteries Vanadia Zinc doping
52	Effects of mill rotational speed on the batch grinding kinetics of a UG2 platinum ore Makgoale, Dineo Mokganyetji 11 1900 (has links) In this study, the effect of speed was investigated on the breakage rate of UG2 platinum ore in a batch mill of 5 dm3 and 175 mm internal diameter. One size fraction method was carried out to perform the experiment. Five mono-sized fractions in the range of 1.180 mm to 0.212 mm separated by √2 series interval were prepared. The fractions were milled at different grinding times (0.5, 2, 4, 15 and 30 min) and three fractions of mill critical speed were considered (20%, 30%, and 40%). The target of critical speed below 50% was due to the need of lower energy consumption in milling processes. The selection and breakage function parameters were determined and compared for fractions of critical speed. First the grinding kinetics of the ore was determined and it was found that the material breaks in non-first order manner. Thereafter, effective mean rate of breakage was determined. It was found that the rate of breakage increased with increase of mill speed and optimum speed was not reached in the range of chosen mill speed fractions. Again the rate of breakage was plotted as a function of particle size, the optimum size was 0.8 mm when milling at 30% critical speed. As for 20% and 30% optimum size was not reached. The selection function parameters estimated at 30% critical speed were 𝑎0 = 0.04 min−1 , 𝛼 = 1.36, 𝜇 = 0.9 mm, and Λ = 3. Breakage function parameters were determined and was noticed that the material UG2 platinum ore is non-normalised, i.e. Φ value was changing from 0.25 to 0.90 depending on feed size and mill speed. The parameters 𝛽 and 𝛾 were constant at 7.3 and 1.17 respectively. / College of Science, Engineering and Technology / M. Tech. (Chemical Engineering) Population balance model Ball milling Communition Size specific energy Selection function Breakage function Mill critical speed Platinum ore Milling kinetics Breakage rate 621.914 Platinum ores Ball mills Grinding machines Milling machinery Rolling-mill machinery Crushing machinery
53	Beräkning av värmeenergiförluster i flerbostadshus genom analys av den totala fjärrvärmeenergianvändningen : / Calculation of the thermal energy losses in apartment buildings through analyze of the total district thermal energy consumption : Fredhav, Dennis, Briggert Sjöstrand, Carl Andreas January 2012 (has links) This thesis has been carried out on behalf of IV Produkt AB and intends to set an average ratio of thermal energy losses in apartment buildings that were built during the 1960-1990. This shall be derived by analyzing the total district energy consumption that has been divided into three parts: heat energy losses (the actual heating requirements), the heating of domestic hot water and heating energy consumption for the controlled ventilation. Three different residential areas that were built during the years 1962-1966 and one that was built in 1993 has been analyzed. All residential areas are located in Växjö urban and contains between four and six apartment buildings. The analyzed objects have a mechanical exhaust ventilation systems and district heating as the heating method. No own laboratory work or experiments have been done in this thesis, the calculations have been done on the basis of parameters from VEAB, interviews with property managers, and literature studies. By calculations, we have got a result that is reported in Chapter 6. The result is given as a thermal energy loss as a percentage of the total heat consumption. In this thesis there has also been a review of the rules on requirements for the specific energy consumptions in buildings, indoor environment and indoor temperature from the National Board of Housing and the National Board of Health and Welfare. district heating degree-day method degree hours-method specific energy consumption of buildings värmeenergiförluster i flerbostadshus fjärrvärme normalårskorrigering graddagsmetod gradtimmar byggnaders specifika energiförbrukning myndigheters krav på inomhusmiljö
54	Thermal Snail : Design and Performance Evaluation of a Non-Electronic Autonomous Vehiclefor Harnessing Thermal Expansion of Volatile Fluid for Movement Chen, Xin, Velin, Benjamin January 2024 (has links) No description available. Energy Harvesting Temporal Gradient Energy Density Spring Constant Amount Of Work Mobile Robot Direct Sunlight Working Fluid Propionate Phase Transition Heat Transfer Phase Change Pressure Measurements Renewable Sources Thermal Energy Vapor Pressure Gas Constant Gas Pressure Specific Energy Hot State Vehicle Wheel Dust Storms Solar Panels Constant Returns Energy Harvesting System Fluid Composition Storage Devices Physical Sciences Fysik

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