8,959 Works

Investigations into the Effects of Biofuel Contaminants on Solid Oxide Fuel Cells

Hossein Madi
Solid Oxide Fuel Cells (SOFCs) have gathered considerable attention as a clean, highly efficient conversion device for the production of both electricity and heat from fuels. Due to their high operating temperatures, SOFCs do not require pure hydrogen as fuel, but exhibit a high fuel flexibility, a major advantage concerning the high cost of hydrogen production. Nonetheless, certain requirements apply in terms of fuel purity. The presence of contaminants such as sulfur compounds, siloxanes, halogens,...

Optimal application-oriented resource brokering in a high performance computing grid

Vincent Keller
In the world of High Performance Computing (newly renamed "High Productivity Computing"), where the race for performance is on, where the hunt for the last Flop rages and where the developers swear by the Cult of Power, the different applications have different needs. Some of them are single threaded, others are parallel, some are memory bandwidth, others processor speed dominated. Some are embarrassingly parallel, point-to-point or multicast dominated, all depending on the algorithms and numerical...

Modeling and optimization of Tunnel-FET architectures exploiting carrier gas dimensionality

Cem Alper
The semiconductor industry, governed by the Moore's law, has achieved the almost unbelievable feat of exponentially increasing performance while lowering the costs for years. The main enabler for this achievement has been the scaling of the CMOS transistor that allowed the manufacturers to pack more and more functionality into the same chip area. However, it is now widely agreed that the happy days of scaling are well over and we are about to reach the...

Neuroimaging of human auditory cortex:data analysis and applications

Naghmeh Ghazaleh
Modern neuroimaging technologies provide us with non-invasive methods for study- ing structure and function, and plasticity of the human auditory cortex. Here we have acquired high spatial resolution functional magnetic resonance imaging (fMRI) data of the auditory cortex in patients with unilateral hearing loss and tinnitus. Compared to healthy controls, we found evidence of over-representation and hyperactivity in parts of cortical tonotopic map that correspond to low frequencies sounds, irrespective of the hearing loss and...

Two-handed gestures for human-computer interaction

Agnès Just
The present thesis is concerned with the development and evaluation (in terms of accuracy and utility) of systems using hand postures and hand gestures for enhanced Human-Computer Interaction (HCI). In our case, these systems are based on vision techniques, thus only requiring cameras, and no other specific sensors or devices. When dealing with hand movements, it is necessary to distinguish two aspects of these hand movements: the static aspect and the dynamic aspect. The static...

Toward ultra-low power design methodology for frequency generation in the IoT design space

Mathieu Yves Hervé Coustans
Today, the semiconductor industry is feeding our digital world with more and more data coming from compact embedded electronics that are monitoring our environment and feeding analytics for action. Interaction with our digital world is mostly achieved through Internet connectivity. The idea of the Internet of Things (IoT) extends the concept of a digital world into the physical world through these autonomous systems on a chip (SoC). In a ubiquitous object with a small-form-factor, power...

Impedance Spectroscopy for Single Cell Analysis and Dispensing

David Vincent Bonzon
Flow cytometry is an essential tool in biology and medicine with applications in immunodeficiency diagnostic, immunosurveillence, organ transplantation in addition to its basic research usage. Before the widespread use of the Fluorescent-Activated Cell Sorting (FACS), the first flow cytometer was invented by Wallace Coulter and was embodied in a remarquably simple device. The Coulter counter principle consists in passing particles in an aperture concurrently with an electric current to measure the related impedance variations. In...

In vivo diffusion magnetic resonance imaging of the white matter microstructure from dictionaries generated by Monte Carlo simulations: development and validation

Gaëtan Olivier D. Rensonnet
Non-invasive virtual histology of white matter tissues is the ultimate promise of diffusion-weighted MRI (DW-MRI). This hope is fueled by the exquisite sensitivity of DW-MRI to micrometer-scale displacement of diffusing water molecules, averaged over a whole voxel. Combined with adequate mathematical modeling, DW-MRI therefore has the potential to provide unprecedented, microscope-like insight into the microstructure of the brain, with important consequences in brain neurosciences, neurology and psychiatry. Many closed-form analytical models have been proposed to...

The telomeric DNA damage response: Insights into telomere compaction and identification of novel damage signaling factors

Aleksandra Vancevska
Telomeres are dynamic nucleo-protein structures capping the ends of all eukaryotic chromosomes. Together with telomerase, they counteract replication-dependent telomere attrition. Additionally, they disguise the linear ends of the chromosome from the DNA damage response (DDR) machinery. Otherwise, the chromosome end would be recognized as a DSB and would elicit a deleterious DDR signal. Both of these functions contribute greatly to the maintenance of genome stability. Telomeres are composed of repetitive DNA sequences, protein complex dubbed...

Long-term evolution of solid oxide fuel and electrolysis cell 3-D microstructure

Giorgio Rinaldi
Solid oxide fuel cells (SOFC) are highly efficient electrochemical conversion devices for the production of electricity that combine fuel flexibility with low emissions of pollutants. The reverse operation in electrolysis mode (SOEC) allows storing electrical energy into fuels, such as hydrogen and synthetic methane. The mitigation of the detrimental microstructural alterations upon long-term operation requires the understanding of the phenomena causing the changes and of the effects on the electrochemical performance. The standard electrodes fabrication...

Indole Alkaloids, Macrocycles and Heterocycles:Interplay between Methodological Development and Total Synthesis

Cyril Piemontesi
An enantioselective total synthesis of (-)-terengganensine A, a heptacyclic monoterpene indole alkaloid, was performed. A short sequence allowed to obtain the enantio-enriched target in good overall yield. The synthesis featured a key asymmetric transfer hydrogenation of iminium as well as a complex domino dihydroxylation, oxidative cleavage, triple cyclization, hydrolysis sequence. An excellent stereocontrol was achieved thanks to a strategy based on an in-depth conformational analysis of the substrates. A divergent synthesis of (-)-vallesamidine and of...

Applications of Artificial Intelligence to Computational Chemistry

Nicholas John Browning
The calculation of the electronic structure of chemical systems, necessitates computationally expensive approximations to the time-independent electronic Schrödinger equation in order to yield static properties in good agreement with experimental results. These methods can also be coupled with molecular dynamics, to provide a first principles description of thermodynamic properties, dynamics and chemical reactions. Evidently, the cost of the underlying electronic structure method limits the time frame over which a system can be studied, and hence,...

Targeting mitochondrial bioenergetics and NAD+ metabolism during sarcopenia and regeneration of skeletal muscle

Tanja Sonntag
The progressive decline of muscle mass and function called sarcopenia is a multi-factorial process associated to frailty, disability, and low quality of life in the elderly. The co-factor nicotinamide adenine dinucleotide (NAD+) becomes a limiting factor in the course of aging and other pathological conditions. It has emerged as a major regulator of cellular metabolism, which is modulated by dietary precursors of the vitamin B3 family. So far, no direct link between sarcopenia and alterations...

Two nanomachines drive evolution in diverse Vibrio species

Noémie Matthey
Horizontal gene transfer (HGT) has a major impact on bacterial evolution, leading to acquisition or deletion of genes and gene clusters, including those encoding antibiotic resistances and virulence factors. HGT therefore contributes to pathogen emergence, which can have a major impact on human health. As a mode of HGT, natural competence for transformation allows bacteria to directly acquire DNA from the environment and to integrate parts of this genetic material within their genomes. The human...

Asynchronous Simulation of Neuronal Activity

Bruno Ricardo Da Cunha Magalhães
Simulations of the electrical activity of networks of morphologically-detailed neuron models allow for a better understanding of the brain. Short time to solution is critical in order to study long biological processes such as synaptic plasticity and learning. State-of-the-art approaches follow the Bulk Synchronous Parallel execution model based on the Message Passing Interface runtime system. The efficient simulation of networks of simple neuron models is a well researched problem. However, the efficient large-scale simulation of...

Bioengineering human bone marrow models to elucidate the triggers of the stem cell niche

Queralt Vallmajó Martín
The bone marrow (BM) microenvironment, or niche, significantly affects behaviors of its resident stem cell populations. Disruptions in the BM niche contribute to a number of severe clinical pathologies. Discovery of novel therapeutic strategies for BM-related diseases necessitates development of superior preclinical models to study parameters affecting BM homeostasis. To address this, a poly(ethylene glycol) hydrogel featuring a particular crosslinking chemistry based on the enzyme transglutaminase factor XIII, dubbed TG-PEG, was utilized to engineer humanized...

Uncertainty quantification in unfolding elementary particle spectra at the Large Hadron Collider

Mikael Johan Kuusela
This thesis studies statistical inference in the high energy physics unfolding problem, which is an ill-posed inverse problem arising in data analysis at the Large Hadron Collider (LHC) at CERN. Any measurement made at the LHC is smeared by the finite resolution of the particle detectors and the goal in unfolding is to use these smeared measurements to make nonparametric inferences about the underlying particle spectrum. Mathematically the problem consists in inferring the intensity function...

Higher brightness beams from the SPS for the HL-LHC era

Francesco Maria Velotti
The need to push the LHC beyond its limits and increase the deliverable luminosity to the experiments by about one order of magnitude has driven the ongoing injector and HL-LHC upgrades. The higher luminosity requires to increase the beam brightness, which directly translates in the need to adapt the different machine protection systems. Among all the foreseen upgrades, the transfer line collimators (TCDI) and the LHC injection protection systems will be revised. In particular, the...

Microcavity light emitting diodes in the visible red and near infrared wavelength range

Reto Joray
It was about 125 years ago that the light bulb was commercialized by Thomas Edison. No doubt a brilliant invention at the time, today its low power conversion efficiency is one of the reasons why lighting in the western world has such high energy consumption. Thus, the potential for saving energy is enormous in this area. The introduction of halogen, discharge and fluorescent lamps has lead to certain efficiency improvements, however more than half of...

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