Littérature scientifique sur le sujet « Bennet's doubler »

Abraham Bennet was a clergyman and electrical experimenter who invented the gold-leaf electroscope and the doubler of electricity. He used a mechanical revolving version of the latter to devise a concept of ‘adhesive electricity’, which had an important influence on Volta in the formulation of his contact theory of electromotivity. Bennet managed to balance his clerical position, obtained by patronage, with the friendship and assistance of the local philosophical community, which included Erasmus Darwin, White Watson and the members of the Lunar and Derby Philosophical Societies. The Lunar members helped him to publish his research and supported his nomination as F.R.S. in 1789; however, the relative harmony of the philosophical community represented by the Royal Society, which temporarily united provinces and metropolis, was shattered by the political turbulence of the revolutionary era. The delicate balancing act that allowed Bennet to claim support from Banks and Kaye at the same time as from Priestley and Darwin became more difficult and Bennet's research activity foundered due to ill health and political division.

The many facets of Bennett's investigation into his skew four-bar linkage and its several extensions have given rise to an abundance of studies by other workers. Among his imaginative endeavours was the deployment of a double helix to convert his planar 12-bar network into a spatial counterpart. A geometrically attractive idea, its algebraic equivalent had been difficult to realize because of a lack of underlying analytical relationships. As well, recent papers have revealed apparent shortcomings in Bennett's representation. The present work is an attempt to provide a complete algebraic treatment of Bennett's novel device.

AbstractThis article explores Alan Bennett’s Single Spies (1988), an espionage double bill comprising “An Englishman Abroad” and “A Question of Attribution,” proposing that the personalizing of social, political, and historical themes, as well as the astute documentation of a decaying Englishness and its class system in both plays, are representative of the work of a playwright whose output deserves serious critical attention. The study focuses on how Bennett historicizes the actions of his infamous protagonists (Guy Burgess and Anthony Blunt) while challenging assumptions regarding patriotism. Single Spies is a Cambridge Five franchise, demonstrating the playwright’s characteristic wit, irony, and reflection on personal and national identity, illusion, and sacrifice. The one-act plays each deal with a key figure in the notorious Cambridge spy ring, enhancing the dramatic effect through the use of onstage theatrical and visual allusions. In the first play, references to William Shakespeare’s Hamlet (c 1599), together with English music, highlight Burgess’s duality and the bitter reality of his post-defection life in Russia, while the second play is notable for its use of two paintings (Titian and a Venetian Senator and Allegory of Prudence) as key images and conceits suggesting the gradual uncovering of the Cambridge Five. The paper therefore suggests that Bennett’s ability to lift the veil of personal and institutional secrecy, while airing his own ambivalence, confirms him as a skillful, if academically undervalued, commentator on Englishness.

Alan Bennett is one of the most popular mainstream dramatists working in Britain today, his canon now a mainstay of regional and amateur theatre companies. Yet for a writer who was once compared to John Osborne as taking ‘the moral temperature of the nation’, his output is widely regarded as apolitical and, at worst, ‘safe’. In the following article, Richard Scarr suggests that this viewpoint is misleading, and argues that Bennett is not only one of the most politically contentious playwrights in dominant theatre, but that the ideological viewpoints he has supported have changed as his career has progressed. Richard Scarr is an English graduate of the University of North London, and has recently completed an MA in Renaissance Studies at Queen Mary and Westfield College. He is currently researching a PhD on the rhetoric of Renaissance comedy, with particular emphasis on the double-entendre.

La récupération de l'énergie est le processus qui consiste à convertir l'énergie inutilisée présente dans notre environnement en énergie électrique utilisable pour alimenter un système électronique. Les récupérateurs d'énergie cinétique à transduction électrostatique (eKEH) utilisent l'énergie cinétique présente dans l’environnement, qui provient d'un objet en mouvement ou de vibrations, afin de la convertir en énergie électrique. Le principe employé est basé sur un condensateur variable polarisé. En ajoutant une couche triboélectrique entre ses armatures et en créant un contact entre elles, un eKEH devient ce qui l’on appelle communément un nanogénérateur triboélectrique (TENG). Ce type de transducteur accumule des charges par contact dans la couche triboélectrique qui devient ainsi un électret dont le champs électrique semi-permanent généré permet une variation de la distribution des charges électriques dans les électrodes par induction électrostatique.La modification de l'architecture d'un TENG par l'ajout d'une troisième électrode permet de transformer un transducteur à capacité simple en un TENG à capacité double. Le fait de doubler l'élément de conversion dans un transducteur doit permettre d’augmenter la quantité d'énergie convertie. Le circuit électronique choisi pour redresser le signal obtenu en sortie du générateur est le doubleur de Bennet. L’absence de tension de saturation en sortie de ce circuit est une caractéristique particulière de cette pompe de charge dite instable. Elle se traduit par une augmentation exponentielle de la tension de sortie et des charges accumulées dans le condensateur de stockage qui augmentent (en théorie) de manière infinie. Cela signifie que la surface du cycle charge-tension aux bornes du TENG, et donc l’énergie convertie du domaine mécanique, augmente à chaque itération du cycle mécanique du transducteur.Cette thèse comprend l'analyse, la simulation et la démonstration expérimentale d’un doubleur de Bennet comportant deux capacités variables asymétriques incluant chacune une couche triboélectrique. Il est montré que les performances du système « double TENG » - « double Bennet » sont supérieures au doubleur de Bennet classique. L'étude analytique s'aligne sur les simulations. Le système a été testé expérimentalement. Il en est conclu que les résultats expérimentaux sont pertinents lorsqu'ils sont comparés aux performances du système classique d’un « TENG mono-capacitif » - « Bennet simple». Par rapport au doubleur de Bennet classique, le double Bennet atteint les mêmes niveaux de tension en moins de temps. Cela est dû à l'avantage du double condensateur TENG qui augmente le nombre de charges accumulées par cycle mécanique. L'analyse a montré que les deux condensateurs TENG sont co-dépendants et qu’ils s’influencent mutuellement lorsqu’ils sont mis en fonction.Le signal de sortie du double Bennet est caractérisé par des tensions élevées allant de plusieurs centaines à plusieurs milliers de volts. Pour abaisser la tension redressée en sortie à un niveau compatible avec une application commerciale, un convertisseur DC-DC de type Buck est implémenté. Celui-ci nécessite un interrupteur. Cette thèse propose et étudie l'utilisation d'un interrupteur haute-tension MEMS dit à micro-plasma dont la tension d’actionnement est définie par la loi de Paschen. Cette thèse se conclue par une étude théorique et expérimentale de cette loi à l'échelle micrométrique dans le but de proposer des tensions d’actionnement optimales pour une meilleure gestion de l'énergie captée
Energy harvesting is the process that involves converting otherwise unused energy present in our environment into usable electrical energy that can be used to power an electronic system. Electrostatic kinetic energy harvesters (eKEHs) utilize vastly present kinetic energy that originates either from an object in motion or vibrations and converts it into electrical energy. The employed principle is based on a polarized variable electrostatic capacitor. With an addition of a triboelectric layer between its plates and utilizing the triboelectrification effect, an eKEH is transformed into a triboelectric nanogenerator (TENG). This type of transducer accumulates charges by contact in the triboelectric layer which thus becomes an electret whose generated semi-permanent electric field allows a variation of the distribution of the electric charges in the electrodes by electrostatic induction.Altering the architecture of a TENG by adding the third electrode, a single-capacitive transducer is converted into a double-capacitive TENG. Doubling the conversion element in a transducer is expected to increase the amount of converted energy. Chosen electronics circuit to condition obtained signal from the generator is Bennet’s charge doubler. An increase without saturation point at the output of this circuit is the unique characteristic of this unstable charge pump. It reflects through an exponential increase of output voltage and a number of charges accumulated in the storage capacitor which increase (in theory) in an infinite way. This means that the surface of the charge-voltage cycle at the terminals of the TENG, and thus the converted energy of the mechanical domain, increases at each iteration of the mechanical cycle of the transducer.The scope of this thesis encompasses the simulation, analytical and experimental research of Bennet’s charge doubler with two asymmetric variable capacitors each containing a triboelectric layer. It is postulated that the performance of the "double TENG" - "double Bennet" system is superior to the classic Bennet’s double. The results of analytical and simulation analysis have shown that the expected behavior of this circuit aligns with hypothesized performance results. The system has been tested experimentally. It is concluded that the results of the constructed system are relevant when compared with the reported performance of the classic "single-capacitive TENG" - "Bennet’s doubler" system.When compared with classic Bennet’s doubler, double Bennet reaches the same voltage levels in less time. That is due to the advantage of double capacitive TENG which increases the number of accumulated charges per mechanical cycle. In analytical analysis, it was found that the two TENG capacitors are codependent and that in operation they affect one another.The output signal of double Bennet is characterized by high voltages ranging from a few hundreds of volts to a few kilovolts (kV). To reduce the rectified output voltage to a level compatible with a commercial application, a Buck DC-DC converter is implemented. This requires a switch. This thesis proposes and studies the use of a high-voltage MEMS micro-plasma switch whose actuation voltages is defined by Paschen’s law. Within the scope of this thesis, the theoretical and experimental studies of this law at the micrometer scale propose optimal actuation voltages for better management of the converted energy

Based on the Bennett 4R chain, we construct a rotating loop by fixing one R axis to the frame and the fixed R becomes a coaxial double R pair. The R pair opposite to the fixed double R is replaced by a spherical S pair which can be equivalent to a (RRR) open chain with non-coplanar intersecting axes. In the (RRR) sub-chain, we choose special axes and derive R|- R|(R(RRR)R chain moving with 2 DoFs. That moving R becomes a coaxial double R with the addition of another rigid body and the obtained chain with hybrid topology generates a 3-dof motion, which is mathematically modeled by a 3D submanifold of a 4D group of X motions. Because of the product closure in an X-motion group, adding an H pair with any pitch and an axis parallel to the fixed R axis leads to a mechanical generator of a 4D X-motion group. Then, parallel arrangement of two generators of the same X motion gives a new parallel generator of X motion, which can be actuated by four fixed R pairs; the two Hs must have distinct pitches. A special design with four collinear actuated axes is revealed too.

DNA origami nanotechnology is a recently developed self-assembly process for design and fabrication of complex 3D nanostructures using DNA as functional materials. This paper aims to review our recent progress in applying DNA origami to design of kinematic mechanisms of nanometer scale. These nanomechanisms, which we call DNA Origami Mechanisms (DOM), are made of relatively stiff bundles of double-stranded DNA (dsDNA) which function as rigid links, connected by highly compliant single-stranded DNA (ssDNA) strands which function as kinematic joints. The designs of kinematic joints such as revolute, prismatic, cylindrical, universal and spherical are presented. The steps as well as necessary software or experimental tools for designing DOM with DNA origami links and joints are detailed. To demonstrate the designs, we presented the designs of Bennett 4-bar and crank-slider linkages. At last, a list of technical challenges such as design automation, computational modeling are presented. These challenges could also be opportunities for mechanism and robotics community to apply the well developed kinematic theories and computational tools to design of nanorobots and nanomachines.

This research introduces DNA origami as a viable approach to design and fabricate nanoscale mechanisms and machines. DNA origami is a recently developed nanotechnology that has enabled the construction of objects with unprecedented nanoscale geometric complexity via self-assembly. These objects are made up of thousands of DNA base-pairs packed into 3D structures with typical dimensions of 10–100nm. The majority of DNA origami research to date focuses on assembly of static 2D or 3D structures. In this work, we aim to extend the scope of DNA origami to include design of objects with kinematically constrained moving parts. Borrowing concepts from macro-scale kinematic mechanisms, we propose the concept of DNA Origami Mechanisms and Machines (DOMM) comprised of multiple links connected by joints. The links are designed by bundling double stranded DNA (dsDNA) helices to achieve the desired geometry and stiffness. The joints are designed by combining links with strategic placement flexible single stranded DNA (ssDNA) to enable motion in specific degrees of freedom. We detail design approaches for links and common joints including revolute, prismatic, and spherical, and discuss their integration into higher order mechanisms. As a proof of concept, we built a nanoscale hinge (revolute joint) and integrated four of these hinges into a prototype DOMM, namely a Bennett 4-bar linkage, which can be completely folded into a closed bundle geometry and unfolded into an open square geometry with a specified kinematic motion path. A kinematic analysis shows that the DNA Bennett linkage closely follows the 3D motion path of the rigid body counterpart. Our results demonstrate that DNA origami has high potential for the design and assembly of nanoscale machines. The ultimate goal of this work is to develop a library of nanoscale DNA-based links and joints that can be widely used in the design and assembly of higher order mechanisms and machines. We anticipate that, in the future, these components can be used to build nanorobots for useful applications including drug delivery, nanomanufacturing, and biosensing.