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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Towards Automated Design of Toggle Switch Mechanisms

Kalyan Ramana, G January 2016 (has links) (PDF)
This work deals with addressing the issues related to design of double toggle switch mechanisms with emphasis on structural, dimensional and dynamic aspects. Currently, almost all the issues related to electrical switches are dealt from electromagnetic point of view; the operating mechanism is hardly touched. It is observed that kinematic parameters influence electrical performance of switch significantly. Therefore, there is a need to develop methodologies for supporting exploration of diverse kinematic chains (KCs) for this purpose. Visual inspection is tedious and error prone even when a complete list of design criteria is available, hence, the work presented in the thesis contributes towards automated design of toggle switch mechanisms. In this context, in house modular kinematics data structure is found useful for using it as a tool in the design of toggle switch. Modular kinematics, typically used for kinematic analysis, works on the principle of finding the configuration of a mechanism using a given set of modules by a procedure called module sequence. This module sequence is used and interpreted in a number of ways for its effective use in various design stages. Structurally, a set of seven conditions must be satisfied by a KC to exhibit double toggle. These conditions are broadly classified into three categories: criteria for KC, function assignment criteria and criteria for stoppers. These three criteria are to be checked automatically by use of module sequence in the same order as mentioned. In the criteria for KC, one of the conditions is that, the KC should not have fractionated degrees of freedom (d.o.f.). Hence, detection of fractionation in a KC is inevitable. In literature, is was found that the algorithms for detection operate at their worst case complexity, O(n4), and some of them do not report joint fractionation. Thus, the algorithms are not only robust but also computationally expensive. Therefore, a frugal and comprehensive method O(n2) is implemented to detect fractionation using modular kinematics. Also, inherent structural pattern embedded in fractionated KCs is hardly studied in literature. It is found that the way body and joint fractionation is defined in fractionated KCs is inconsistent. So, fractionation is interpreted as symbolic partitioning of joints and links in the traditional body and joint fractionation types respectively. Based on the number of ways of partitioning, simple and multiple types of fractionation are recognized. Valid partitions are identified using the notion of fractionating and non-fractionating subchains. Relative locations of these subchains influence distribution of d.o.f. across the fractionated KC. Conventional representation of KCs as links and joints or graphs is difficult to comprehend this distribution. For this, a novel concept of fractionation graph is introduced that gives d.o.f. distribution information and the relative locations of the constituent subchains across the KC. Modular kinematics gives a constructive description of fractionated KCs. Characterization of fractionated KCs, based on presence of multiple separation links, is introduced as order of fractionation. Uniqueness for a given order of fractionation is also justified. After the criteria for KC, a KC is tested for feasibility for function assignment criteria. This requires recognition of active and passive subchains of the KC with respect to input and output pairs. For this, module sequence is characterized for recognition of the subchains. Based on these subchains, locations of stoppers are derived. Using this information, an algorithmic approach to assign functions (functions like spring, ground link, input link, etc.) to derive distinct driving mechanisms provided isomorphic elements (links and joints) of the KC are known beforehand, is introduced. The design parameters influencing dimensional synthesis have been identified as dimensions of links, spring anchor points and stopper locations. Sub-problems associated with each parameter are analyzed. It is found out that optimum location of stoppers for selecting operational range of motion is necessary by taking into account the considerations of timing of switch and impact velocity. Based on the analysis, an algorithmic way to design single toggle switch mechanisms is introduced. Timing for closing or opening of a switch is one of the critical measure that determines its performance. Timing should be as low as possible without exceeding the impact velocity at the instant contacts meet each other. Timing of a switch depends on the dimensions of the links, inertial parameters, spring stiffness etc. For a given timing for a mechanism, dynamic synthesis, in this thesis, deals with finding the inertial parameters of the links using Quinn's energy distribution method, modular kinematics, and Nelder and Mead's downhill simplex method for optimization. This thesis helps the designer to use modular kinematics as a potential automated tool to select a valid design to make the solution space more meaningful in the design of toggle switch mechanisms.
2

Real-time control of a genetic toggle switch / Contrôle temps-réel d'une bascule génétique

Lugagne, Jean-Baptiste 13 December 2016 (has links)
Les progrès récents de la microfluidique, la biologie synthétique, la microscopie automatisée rendent aujourd'hui possible le contrôle externe de l'expression des gènes en temps réel. Parmi les défis que devra relever le domaine du contrôle externe et temps-réel de l'expression des gènes, se trouve la possibilité de contrôler des réseaux de régulation génique aux dynamiques complexes et multi-stables et le contrôle de multiples gènes en parallèle. Pour faire avancer le domaine dans cette direction nous avons étudié la contrôlabilité d'un réseau bistable composé de deux gènes, appelé genetic toggle switch, ou bascule génétique, autour de son point d'équilibre instable sur de longues périodes. Dans ce document, nous présentons la mise en place d'une plateforme de contrôle externe de l'expression des gènes en cellule unique, ainsi que le développement d'un châssis cellulaire bactérien et d'une librairie de circuits de bascules génétiques à contrôler. Nous utilisons la plateforme pour diriger et maintenir notre système génétique dans sa région d'instabilité avec des techniques de stabilisation à la fois en boucle ouverte et en boucle fermée. Nous démontrons non seulement que les plateformes de contrôle in silico peuvent être utilisées pour contrôler un système génétique dans un état hors-équilibre, nous démontrons aussi la possibilité de maintenir une population de cellules dans leur région d'instabilité à l'aide de stimulations périodiques en boucle ouverte. Ces résultats suggèrent l'émergence de régimes de stabilité différents dans des réseaux de régulation génique lorsqu'ils sont soumis à des environnements fluctuants, et peuvent fournir de nouvelles perspectives dans l'étude de la prise de décision cellulaire. Nous présentons aussi une nouvelle approche pour l'analyse d'images de microscopie qui exploite l'information cachée dans plusieurs plans focaux autour du spécimen au lieu d'utiliser seulement un seul plan focal. L'objectif de cette méthode est d'identifier automatiquement les différentes parties d'une image à l'aide de techniques d'apprentissage-machine inspirées de l'imagerie hyperspectrale. La méthode facilite la segmentation de l'image et peut être facilement adaptée à différents organismes / Recent progresses in microfluidics, synthetic biology and microscopy automation now make it possible to control gene expression externally and in real time. Among the challenges facing the field of external real-time control of gene expression is the control of intricate, multistable gene regulation networks as well as the control of several target genes at the same time. To advance the domain in this direction we studied the controllability of a simple bistable two-genes network, the so-called genetic toggle switch, in the vicinity of its unstable equilibrium point for extended periods of time. Throughout this document, we present the development of a custom control platform for external control of gene expression at the single-cell level as well as a bacterial cellular chassis and a library of toggle switch genetic circuits for us to control. We use the platform to drive and maintain our genetic system in its region of unstability with both closed-loop and open-loop strategies. Not only do we demonstrate that in silico control platforms can control genetic systems in out-of-equilibrium states, we also notably maintain a population of cells in their unstable area with open-loop periodic stimulations. These results suggest the possible emergence of different regimes of stability in gene regulation networks submitted to fluctuating environments, and can potential insights in the study of cellular decision making. We also introduce a new approach for microscopy image analysis which exploits information hidden in several focal planes around the specimen instead of using only a single-plane image. The objective of this method is to automatically label different parts of an image with machine learning techniques inspired by hyperspectral imaging. The method is then shown to facilitate segmentation and be easily adaptable to various different organisms
3

Systematic Synthesis And Analysis Of Multi-DOF Toggle Mechanisms For Electrical Switches

Deb, Manan 01 1900 (has links) (PDF)
Electrical switches are ubiquitous. Performance requirement for a switch is stringent. The operating mechanism mostly decides the performance of an electromechanical switch. However, design of such mechanisms, which involve discontinuous motions, is not much addressed in literature. The present work proposes a systematic procedure to design and analyze toggle based switching mechanisms. The work defined the toggle phenomenon rigorously, and, based on the behaviour of the toggles, provided a classification scheme for the switch mechanisms. The existing switches fall in two major categories viz., single-toggle and double-toggle switches. The double toggle mechanism is more suitable for high power breaking as it can isolate the system’s behaviour from the operator’s behaviour. The kinematic and geometric attributes of the operating mechanism which affect the toggle sequence and timings have been identified. A systematic simulation based study has been performed to identify the influence of different kinematic and dynamic parameters on the functionality of a double toggle switching mechanism. The influence of the variable moment of inertia and mechanism singularities arising out of introduction of the four bar sub chain on the performance of the system have been studied in detail. It is observed that the performance of the double toggle systems is less susceptible, though not immune to the user behaviour; in extreme scenarios the switching performance could become erratic. The use of an additional spring in an existing system enhanced the system performance; but, connecting the main spring with the coupler link altered the system performance more dramatically. Thus it established that the influence of the kinematic configuration on the performance of a switching mechanism is more pronounced than the dynamic characteristics of a comparable system. For the ab initio design of double toggle switching mechanisms, necessary structural criteria for a mechanism to exhibit double toggle phenomenon have been identified and verified with various 2 d.o.f. systems. It is also established that any double toggle mechanism cannot be used directly as a switching mechanism; the link dimensions, link arrangements and the stopper locations have to be chosen properly. Towards that end, three necessary kinematic criteria for a switching mechanism are identified. A few mechanisms which satisfy all structural and kinematic criteria are identified; the switching and toggle behaviour of these mechanisms are examined through simulations using Pro/Mechanism. Finally, considering all the conditions a is constructed with consideration of mass and geometric shape of the links. Thus, it established that the proposed methodology can systematically generate novel, structurally distinct electrical switches.
4

Kyvadlo čelisťového drtiče / Pendulum jaw crusher

Pitner, Jakub January 2013 (has links)
This master thesis deals with structural design of pendulum for single toggle jaw crusher DC 110x70 and consists of several main parts. The first part focuses on the processing of mineral materials, especially on the process of mechanical uncoupling. The second part compares main characteristics of single toggle and double toggle jaw crushers. The third part deals with the structural nodes for the crusher DC 110x70. Another part is consisted of two variants for the pendulum construction with a comparison of the advantages and disadvantages. For the selected variant is carried out the stress control using Finite element method (FEM) in the program I-DEAS. The last part focuses on the positioning an exit slit for designed pendulum.
5

Kyvadlo čelisťového drtiče 900 x 500 / Pendulum jaw crusher 900 x 500

Hladík, František January 2018 (has links)
This diploma thesis is concerned with a construction design of single toggle jaw crusher DCJ 900x500. In the first part, the theoretical background and ways of material disintegration are discussed. The second chapter describes types of material crushers in general, especially jaw crushers and their parts. The third chapter is concerned with calculations and the design of the most important parts of the machine. The fourth part consists of the crusher power calculation, design of the pendulum and its production technology. The last part includes the result of FEM analysis for the particular variant of pendulum production. The thesis also includes drawing documentation of the crusher and the pendulum.
6

Kyvadlo čelisťového drtiče 1 600 x 1 250 / Pendulum jaw crusher 1 600 x 1 250

Ješuta, Jiří January 2016 (has links)
This thesis deals with the design of the construction of a pendulum of a single toggle jaw crusher. The first part of this thesis treats the mechanical raw minerals disintegration. In the second part the characteristics of a single toggle jaw crusher and double toggle jaw crusher are compared. The third part addresses the calculation and the construction of the main components of the jaw crusher. Next part of the thesis consists of the calculation of the crushing force, the pendulum design, and the method of manufacturing a pendulum. The strength analysis of the designed pendulum using the finite element method (FEM) in program NX-Ideas is made in the last part of this thesis.
7

Study of Magnetization Switching for MRAM Based Memory Technologies

Pham, Huy 20 December 2009 (has links)
Understanding magnetization reversal is very important in designing high density and high data transfer rate recording media. This research has been motivated by interest in developing new nonvolatile data storage solutions as magnetic random access memories - MRAMs. This dissertation is intended to provide a theoretical analysis of static and dynamic magnetization switching of magnetic systems within the framework of critical curve (CC). Based on the time scale involved, a quasi-static or dynamic CC approach is used. The static magnetization switching can be elegantly described using the concept of critical curves. The critical curves of simple uncoupled films used in MRAM are discussed. We propose a new sensitive method for CC determination of 2D magnetic systems. This method is validated experimentally by measuring experimental critical curves of a series of Co/SiO2 multilayers systems. The dynamics switching is studied using the Landau-Lifshitz-Gilbert (LLG) equation of motion. The switching diagram so-called dynamic critical curve of Stonerlike particles subject to short magnetic field pulses is presented, giving useful information for optimizing field pulse parameters in order to make ultrafast and stable switching possible. For the first time, the dynamic critical curves (dCCs) for synthetic antiferromagnet (SAF) structures are introduced in this work. Comparing with CC, which are currently used for studying the switching in toggle MRAM, dCCs show the consistent switching and bring more useful information on the speed of magnetization reversal. Based on dCCs, better understanding of the switching diagram of toggle MRAM following toggle writing scheme can be achieved. The dynamic switching triggered by spin torque transfer in spin-torque MRAM cell has been also derived in this dissertation. We have studied the magnetization's dynamics properties as a function of applied current pulse amplitude, shape, and also as a function of the Gilbert damping constant. The great important result has been obtained is that, the boundary between switching/non-switching regions is not smooth but having a seashell spiral fringes. The influence of thermal fluctuation on the switching behavior is also discussed in this work.
8

Synthesis and Analysis of Cam-Link Mechanisms for Presses

Hung, Yu-Hsiang 27 June 2012 (has links)
Based on the traditional six-bar toggle mechanisms, this study is focused on the design of two types of cam-link mechanisms. Six-bar toggle mechanisms are simple, and they have an extreme mechanical advantage in toggle position so that they are widely used in plastic forming machines. Cam-crank-slider and cam-double-slider linkage are the two types mechanisms that we concerned. And we find the difference between these mechanisms for kinematic and dynamic performance. The benefit of cam-link mechanisms compares to linkage mechanisms is more precision points. We can synthesize the curve profile with the demand for forming acceleration or stroke. Because we need interpret the kinematic characteristic of toggle mechanisms by using several boundaries condition of different curves. This study selects two kinds from foregoing curve for the model.
9

Centraliserad administration av Feature Toggles

Sandström, Oskar, Voxlin, Viktor January 2017 (has links)
Vid kontinuerlig leverans samt långa utvecklingscykler av mjukvara exponeras system som fortfarande inte är färdigställda för användarna. Det ställer krav på att systemets funktionalitet antingen är brukbart eller otillgängligt. Denna utvecklingsparadigm inom den agila metodiken leder till att vissa funktioner behöver döljas för alla eller en viss del användare. Detta kan lösas med Feature Toggles som i sin tur kan skapa komplexitet och redundant källkod om de inte administreras via ett centraliserat system. Denna typ av administrativt verktyg finns i dagsläget endast tillgänglig via betallösningar. Målet med denna studie är att kvalitativt och kvantitativt undersöka tillvägagångssätt för utveckling av en sådan applikation. Genom en agil utvecklingsmetodik, användning av väl etablerade ramverk, bibliotek och standarder skapades ett administrativt system som möjliggör editering, spårning av händelser och sökfunktioner kopplat till Feature Toggles. Utöver denna funktionalitet skapades ett tillhörande Representional State Transfer – Application Programming Interface (REST-API) som bidrar till att konsumerande system kan ta del utav den centraliserade informationen. Vidare ämnar studien undersöka utvecklingsmöjligheter för applikationen vilket resulterade i ytterligare förslag till funktionalitet så som tidsinställda notifikationer om redundans, optimering av redan implementerad funktionalitet och användarautentisering för ökad säkerhet. Efter genomförda metoder uppnådde studien sitt syfte och resulterade i en applikation för administrering av Feature Toggles.
10

Stabilization Implant for Coxofemoral Luxation in Cattle

Jordan, Brianna Ashley 16 August 2022 (has links)
No description available.

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