Vertically aligned carbon nanotubes for supercapacitor and the effect of surface functionalization to its performance

As reliable mobile energy sources became more and more needed and alternative energy demands became more prevalent, the research in advanced energy storage technologies turned into a topic of utmost importance in today's society. Innovative electrode materials that are able to provide increased energy densities and long lifetime must be then be developed. Nanomaterials such as carbon nanotubes are of tremendous prospects in that context. This master thesis aims at realizing an electrochemical capacitor using a vertically grown carbon nanotube array, which is used as electrode in dierent sets of experiments to evaluate its electrical energy storage capability. Cyclic voltammetry and electrochemical impedance spectroscopy are used to determine the specic capacitance of the device, which is composed of two nanotubes electrodes separated by a polypropylene lter, in an adequate electrolyte. The surface chemistry was modied by adding hydroxyl groups onto the nanotubes surface, thus making them hydrophilic and providing an ecient way to increase their storage ability by a factor of two to three. Dierent electrolytes were compared, both aqueous and non aqueous, and the important parameter in choosing an appropriate electrolyte for a high storage ability was shown to be the polarity of the solution. The carried out performance studies gave encouraging results with a maximum energy density of 21 Wh/kg at a power density of 1.1 kW/kg for a hydrophilic electrode using tetraethylammonium tetrafluoroborate in propylene carbonate. Respectively, a maximum power density was found to be 22 kW/kg at energy density of 2 Wh/kg for a hydrophobic sample. This device can be claimed to be entirely carbon-based, with a relatively small ecological print compared to most lithium-based capacitors and inexpensive. The lifetime is also extremely long, indeed more than hundreds of thousands cycles without failure have been achieved

Sustainability and certification for aviation biofuels

With the rapid growth and increased consumption of biofuels worldwide, and the multitude of policy decisions supporting this expansion, growing concerns about the biofuels sustainability have arisen. Therefore, the European project "ITAKA", aiming at supporting the development of aviation biofuels in an economically, socially, and environmentally sustainable manner has devoted considerable effort to take sustainability into account, in a quantitative and qualitative manner. More precisely, a robust assessment of a lifecycle greenhouse gas (GHG) calculation for the produced bio jet fuel have been set up, using the RSB EU RED methodology. This pathway includes feedstock production, feedstock processing, biofuel production, biofuel distillation, and all transport steps involved. A significant reduction in GHG emissions (up to 66%) has been demonstrated

Vertically-Aligned Carbon Nanotubes for Supercapacitor and the Effect of Surface Functionalization to its Performance

Design of an enhanced supercapacitor using vertically-aligned carbon nanotubes as electrode

Untapped seasonal storage potential in Swiss hydropower schemes

• What is the seasonal storage capacity in Swiss hydropower dams? • How could the untapped potential be captured? • What is the impact on the Swiss energy transition

A numerical shoulder simulator to replicate a mechanical shoulder simulator

Joint simulators are widely used to perform pre-(and post) clinical test of joint prostheses. Several experimental or commercial devices already exist for the hip and knee joints, but nothing is available yet for the shoulder joint. The first goal of this project is to extend an existing numerical model of the shoulder joint, in order to simulate an existing shoulder testing machine prototype. The second goal is to compare the model predictions (muscular and articular forces) with the machine measurements. And finally, the last goal is to use this comparative analysis to propose improvements of the model, or the machine, for an optimal correspondence with the physiological and clinical reality. This project will be done in collaboration with a prostheses manufacturer, Tornier (www.tornier.com), which developed the existing prototype

Carbon Derivatives: Exploration of the Nano-Compounds Which Changed the Macroworld

Some fundamental challenges are shaping the world we live in, and the need for alternative materials and energies is one of the most prominent issues of this century, especially in the light of global warming and energy need. Another crucial point concerns health care for a continuously aging population. Carbon can provide a concrete foundation for addressing both these challenges. Examples as different as lithium ion batteries in battery-powered vehicles, filtration systems, and synthetic diamonds for industrial applications all have in common the fact that they cannot work without carbon, in all their different forms. Allotropy is a phenomenon in which an element exhibits several different forms, while keeping some shared chemical and physical properties. Whether for low-cost solar cells, semiconductors, medical devices, fuel cells, or electrodes, carbon is going to play a crucial and a central role

Energy flows monitoring at the Cantonal level

As an increased number of measures (Swiss or European level) aim at developing more sustainable policies for energy management and reduction of CO2 emissions in particular (for example, the 3x20 policy), very few tools currently exist at the regional/cantonal level to monitor the multiple existing energy flows. Energy issues at local and territorial level have become considerably more complex in the last twenty years for a number of reasons. First, new technologies penetrated the market and now compete with fossil-based conversion systems. In addition, energy systems are evolving to systematically become multi-fluid and multi-services. Finally, local and state authorities have taken up a stronger and broader role in terms of energy policy and have committed to ambitious goals in terms of both increased energy efficiency and implementation of renewables. Within this project, a decision-support and monitoring tool for policy makers has been developed, which includes thorough information on the most prominent energy aspects of the Canton of Vaud, and paves the way for establishing more indicators covering environmental and economic aspects. The development of a web-based tool aimed at visualizing the entire energy chain, from energy sources to end-use sectors at the level of a whole Swiss Canton is thus presented here. This tool provides a unifying structure for all the useful information on energy sources, vectors and final consumptions, this approach thereby giving access to a global overview, understanding and monitoring of the energy supply and demand characteristics of any given Canton (or any equivalent subnational territorial entity). The final goal of this approach is to give access to the direct visualization of all energy flows on the platform, thus translating and broadening the national statistics on the energy chain up to the cantonal (territorial) level. Therefore, this innovative tool will allow quantifying energy profiles, modelling conversion nodes along the energy chain, as well as assessing the overall energy balance per end-use sector. This very innovative platform constitutes a centralized energy data repository as well as a quantitative evaluation tool, encompassing most useful energy sources