Port-based modeling and optimal control for a new very versatile energy efficient actuator

In this paper, we analyze in depth the innovative very versatile and energy efficient (V2E2) actuator proposed in Stramigioli et al. (2008). The V2E2 actuator is intended to be used in all kind of robotics and powered prosthetic applications in which energy consumption is a critical issue. In particular, this work focuses on the development of a port-based Hamiltonian model of the V2E2 and presents an optimal control architecture which exploits the intrinsic hybrid characteristics of the actuator design. The optimal control guarantees the minimization of dissipative power losses during torque tracking transients

Optimal Constrained Planning for Complex Mechatronic Systems

This thesis focuses on the challenging problem of the optimal planning for mechatronic systems. The goal is to find strategies which maximize or minimize some cost criteria defined over a given constrained problem. The planning for mobile or industrial robots is a general framework under which several different open research issues can be found. Motion planning, in fact, involves the solution of a variety of optimality problems which range from the optimal path design to the optimal trajectory planning. Since, obviously, this is a very wide research field the scope of our analysis has been limited to three main contributions which represents the novelties proposed in this thesis. Initially, the optimal path generation problem is solved in the case of planar paths for mobile robots by using a new and powerful planning primitive recently proposed in the literature. Subsequently, the optimal path tracking problem is handled by a new control scheme able to online optimal scale any designed trajectory, which can be phisically unfeasible for the controlled system, in order to fulfill given kinematic and/or dynamic constraints. Finally, the problem of the generation of optimal controls for the minimum-time state transitions of nonlinear systems is presented and an innovative differential method is devised.La tesi tratta il problema della pianificazione ottima vincolata per sistemi meccatronici. In generale, l'obiettivo è la determinazione di strategie che minimizzino o massimizzino funzionali di costo definiti su dati problemi vincolati. Il termine di pianificazione ottima riferito a dispositivi robotici mobili o industriali individua una vasta area di ricerca all'interno della quale numerosi problemi di ottimizzazioni sono ancora indagati. La pianificazione di moto, infatti, richiede la risoluzione di una ampia varietà di problemi di ottimizzazione vincolata che spazia dalla ottima pianificazione di percorso alla pianificazione di traiettoria. Nella presente tesi, l'obiettivo di ricerca è stato limitato a tre importanti contributi innovativi. Inizialmente viene affrontato il problema della pianificazione di percorsi planari ottimi per dispositivi mobili mediante l'uso di una nuova ed estremamente versatile primitiva di pianificazione proposta in letteratura. Successivamente si affronta il problema dell'inseguimento di percorso. E' proposta una nuova struttura di controllo in grado di scalare in linea qualsiasi traiettoria pianificata, che potrebbe essere fisicamente irrealizzabile, in modo tale che i vincoli cinematici e dinamici che il sistema controllato impone siano soddisfatti. Infine si analizza il problema della generazione ottima di set-point per transizioni dello stato di generici sistemi nonlineari ed, in particolare, un innovativo metodo puramente differenziale per il controllo a tempo minimo è descritto

Interaction of Caffeine with Model Lipid Membranes

Caffeine is not only a widely consumed active stimulant, but it is also a model molecule commonly used in pharmaceutical sciences. In this work, by performing quartz-crystal microbalance and neutron reflectometry experiments we investigate the interaction of caffeine molecules with a model lipid membrane. We determined that caffeine molecules are not able to spontaneously partition from an aqueous environment, enriched in caffeine, into a bilayer. Caffeine could be however included in solid-supported lipid bilayers if present with lipids during self-assembly. In this case, thanks to surface-sensitive techniques, we determined that caffeine molecules are preferentially located in the hydrophobic region of the membrane. These results are highly relevant for the development of new drug delivery vectors, as well as for a deeper understanding of the membrane permeation role of purine molecules

Bowling for Calibration: An Undemanding Camera Calibration Procedure Using a Sphere

Camera calibration is a critical problem in computer vision. This paper presents a new method for extrinsic parameters computation: images of a ball rolling on a flat plane in front of the camera are used to compute roll and pitch angles. The calibration is achieved by an iterative Inverse Perspective Mapping (IPM) process that uses an estimation on ball gradient invariant as a stop condition. The method is quick and as easy to use as throw a ball and is particularly suited to be used to quickly calibrate vision systems in unfriendly environments where a grid is not available. The algorithm correctness is demonstrated and its accuracy is computed using both computer generated and real images

Effects of model membranes on lysozyme amyloid aggregation

Abstract The study of the interaction between lipid membranes and amyloidogenic peptides is a turning point for understanding the processes involving the cytotoxicity of peptides involved in neurodegenerative diseases. In this work, we perform an experimental study of model membrane–lysozyme interaction to understand how the formation of amyloid fibrils can be affected by the presence of polar and zwitterionic phospholipid molecules (1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine [POPC] and 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoglycerol [POPG]). The study was conducted above and below the critical micellar concentration (CMC) using dynamic light scattering (DLS), atomic force microscopy (AFM), UV–Vis spectrophotometry, and the quartz crystal microbalance (QCM). Our results show that the presence of phospholipids appears to be a factor favoring the formation of amyloid aggregates. Spectrophotometric and DLS data revealed that the quantity of β {\rm{\beta }} -structure increases in the presence of POPG and POPC at different concentrations. The presence of POPG and POPC increases the speed of the nucleation process, without altering the overall structures of the fibrillar final products

Nanopinces optiques à base de modes de Bloch lents en cavité

Ce travail de thèse s inscrit dans les efforts actuellement réalisés, pour améliorer l efficacité des pinces optiques conventionnelles qui permettent de manipuler sans contact des objets de quelques dizaines de nanomètres à quelques dizaines de micromètres avec une extrême précision et trouvent de nombreuses applications en biophysique et sciences de colloïdes.L objectif de cette thèse a été d explorer une nouvelle approche pour la réalisation de Nanopinces Optiques. Elle s appuie sur l utilisation de cavités à cristaux photoniques à modes de Bloch lents. Ces cavités peuvent être efficacement et facilement excitées par un faisceau Gaussien à incidence normale. Contrairement aux pinces optiques conventionnelles, des objectifs à faibles ouvertures numériques peuvent être utilisés. Les performances attendues en termes de piégeage vont bien au-delà de limitations imposées par la limite de diffraction pour les pinces conventionnelles. Ce travail démontre expérimentalement l efficacité de l approche. Cette thèse comporte deux parties principales. Dans un premier temps, il a fallu monter un banc expérimental pour mener nos études. Nous avons construit un banc optique, interfacé les instruments, et développé des applications logicielles pour analyser les données. Deux éléments importants ont présidé à sa construction : - Le développement d un système optique permettant d exciter les nanostructures photoniques - la conception d un système d imagerie pour suivre les nanoparticules. La seconde partie de ce travail a porté sur la mise en évidence du piégeage optique à l aide de nanostructure à base de cristaux photonique. Nous avons d abord montré que même des cavités possédant des coefficients de qualités modérés (quelques centaines) permettait d obtenir des pièges optiques dont l efficacité est d un ordre de grandeur supérieur à celui de pinces conventionnels. Fort de ce résultat, nous avons exploré un nouveau type de cavité à cristaux photoniques s appuyant sur une approche originale : des structures bi-périodiques. Nous avons montré qu à l aide de cette approche des facteurs de qualités de l ordre de plusieurs milliers étaient facilement atteignable. A l aide de ces nouvelles structures, nous sommes arrivés aux résultats le plus important de ce travail : le piégeage de nanoparticules de 250nm de rayon avec une puissance optique incidente de l ordre du milliwatt. Une analyse fine du mouvement de la nanoparticule, nous a permis de trouver la signature du mode de Bloch lent.This thesis aims at improving the efficiency of conventional optical tweezers (cOT). They allow to manipulate objects with dimension from a few tens of nanometer to a few tens of micrometers with a high accuracy and without contact. This has numerous applications in biophysics and colloidal science. This thesis investigates a new approach for optical nanotweezers. It uses a photonic crystal (PC) cavity which generates a slow Bloch mode. This cavity can be effectively and easily excited with a Gaussian beam at the normal incidence. Contrarily to cOT, objective with a small numerical aperture can be used. The expected performances in terms of trapping go well beyond the diffraction limit of cOT. This work demonstrates experimentally the efficacy of approach. This thesis is divided in two main sections. First, we had to set up an experimental bench to carry out to our study. We built the optical bench interface instruments and develop programs to analyze the data. Two essential elements have been considered: - The development of the optical system allowing the excitation of the photonics nanostructure. - The design an imaging system to track nanoparticles. Second, we have focus on the demonstration of the optical trapping. We started by with a low Q factor (few hundred) cavity. Trapping efficiency of an order of magnitude higher than cOT has been demonstrated. Then, we have explored a new king of PC cavity based on double period structure. We show that thanks to this approach high Q factor of several thousand are easily reached. With this structure, we managed to trap 250nm polystyrene beads, with an optical power of the order of a milliwatt. A deep analysis of the nanoparticle trajectories allowed us to find a slow Bloch mode signature.VILLEURBANNE-DOC'INSA-Bib. elec. (692669901) / SudocSudocFranceF

Changes In Liver Cell Dna Methylation Status In Diabetic Mice Affect Its Ft-ir Characteristics.

Lower levels of cytosine methylation have been found in the liver cell DNA from non-obese diabetic (NOD) mice under hyperglycemic conditions. Because the Fourier transform-infrared (FT-IR) profiles of dry DNA samples are differently affected by DNA base composition, single-stranded form and histone binding, it is expected that the methylation status in the DNA could also affect its FT-IR profile. The DNA FT-IR signatures obtained from the liver cell nuclei of hyperglycemic and normoglycemic NOD mice of the same age were compared. Dried DNA samples were examined in an IR microspectroscope equipped with an all-reflecting objective (ARO) and adequate software. Changes in DNA cytosine methylation levels induced by hyperglycemia in mouse liver cells produced changes in the respective DNA FT-IR profiles, revealing modifications to the vibrational intensities and frequencies of several chemical markers, including νas -CH3 stretching vibrations in the 5-methylcytosine methyl group. A smaller band area reflecting lower energy absorbed in the DNA was found in the hyperglycemic mice and assumed to be related to the lower levels of -CH3 groups. Other spectral differences were found at 1700-1500 cm(-1) and in the fingerprint region, and a slight change in the DNA conformation at the lower DNA methylation levels was suggested for the hyperglycemic mice. The changes that affect cytosine methylation levels certainly affect the DNA-protein interactions and, consequently, gene expression in liver cells from the hyperglycemic NOD mice.9e10229

ACORDOS MARCO GLOBAIS: UM INSTRUMENTO AO SINDICALISMO GLOBALIZADO

RESUMO: As transformações do capitalismo contemporâneo expressados na globalização financeira, nos avanços tecnológicos e nas práticas neoliberais de flexibilização das relações de trabalho, acompanhadas de uma reorganização da estrutura produtiva, impactaram na representatividade sindical, no enfraquecimento de sua estrutura organizacional e financeira. Muitos debates surgem para discutir a perspectiva do sindicalismo. Considerando a elaboração da teoria da revitalização, a hipótese possível, apesar dos imensos obstáculos e desafios, é que há novas formas de ação e organização. Neste sentido, o presente artigo não pretende esgotar todas as reflexões que vislumbram o processo de retomada das ações sindicais, mas apesar exemplificar possibilidades a partir de dois exemplos:  as perspectivas dos acordos marco globais e de ações coletivas de trabalhadores da era digital