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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.
41

Beitrag zur Dimensionierung von Fördersystemen mit Staurollenketten / A contribution to dimensioning of conveyor systems with accumulation roller chains

Dombeck, Uwe 04 April 2013 (has links) (PDF)
Die Arbeit beschäftigt sich mit der Untersuchung der Beanspruchungen von Staurollenketten. Zunächst wurde in den Grundlagen der Aufbau von unterschiedlichen Staurollenkettenarten dargestellt, die Eigenschaften miteinander verglichen und kategorisiert. Aufbauend auf dem anschließend geschaffenen Verständnis der wirkenden Reibpaarungen bzw. -arten wurden FEM-Analysen durchgeführt, um dadurch auftretende Spannungen zu detektieren und das thermische Verhalten der unterschiedlichen Werkstoffpaarungen zu ermitteln. Innerhalb der praktischen Versuche der Arbeit kam es zur Ermittlung der Bruch- und Dauerfestigkeiten nach ISO15654 [DIN04]. Zur Untersuchung der Eigenschaften der Ketten unter praxisnahen Randbedingungen wurde ein Versuchsstand konzipiert, welcher die Ermittlung von Kennwerten zwei unterschiedlicher Kettengrößen unter härtesten Bedingungen ermöglicht. Durch diesen Versuchsstand wurden die Staukraft, die Kettenzugkraft durch das Drehmoment am Antrieb, die Kettengeschwindigkeit, die Kettenlängung und das Temperaturverhalten dauerhaft überwacht. Im letzten Kapitel der Arbeit wurde eine Überwachungsstation für unterschiedliche Baugrößen von Staurollenketten entwickelt und die Funktionsweise durch Versuche nachgewiesen. / This dissertation is dealing with the investigation of the load behaviour of accumulation roller chains. Initially, the structures of different types of accumulation roller chains are described, properties are compared and categorised. Based on the created understanding of acting tribological pairing and friction mechanisms, FEM analysis have been performed to evaluate occurring stresses and determine the thermal behaviour of the various material combinations. Within the testing procedures, breaking strength and fatigue strength have been investigated in accordance with DIN ISO 15654 [cf. DIN04]. A test bench has been developed for practically relevant testing of the chains, where determination of characteristic values can be done under hard testing conditions for two different chain types. The test bench ensures measurement and survey of accumulation forces, tensile chain forces (by torque moment at drive), chain speed, chain elongation and chain temperature during whole testing time. The last chapter of the dissertation deals with the development of a 'control and monitoring unit' for accumulation roller chains with various dimensions including proof of function by trials.
42

Návrh řetězového vlečníku s vytvářením dávky tyčí / Design of chain transfer with creating a batch of bars

Horký, Pavel January 2018 (has links)
The diploma thesis deals with the design of mechanism for manipulation with bars and creating a batch of square steel bars. In intoduction of this thesis is describtion of principle of curent mechanisms. In following chapters are described the most important parts of new mechanism and their design. In final sections are risk analysis and financial evaluation.
43

Moderní aktivní prvky a jejich chování v lineárních blocích / Modern active elements and their behavior in linear circuit blocks

Kosztyu, Tomáš January 2009 (has links)
The topic of this master’s thesis was a frequency filters and their realization using modern active elements like UVC, UCC, VFA, CFA and OTA. The base point of this thesis was designed frequency filters with these active elements, when the shape of the transfer function will be identical for all structures and compare the characteristics of active elements. The proposed frequency filters are second order with one or two active elements. In the first part of thesis are discussed basic properties of frequency filters, their properties and distribution. Next are described the general characteristics of active filters and their basic elements such as operational amplifier OTA, VFA and CFA, and recently more frequently used voltage and current conveyor. The second part is the frequency filters designed with these elements is the same transfer function. Subsequently, simulations are done all the filters and obtained the frequency response. Finally, these filters are experimentally made and made practical measurements.
44

Nelineární obvodové struktury s proudovými a napěťovými konvejory / Nonlinear circuit structures using current and voltage conveyors

Gabriel, Viktor January 2010 (has links)
This thesis deals with the use of active components in nonlinear circuits. First the variants of the current and voltage conveyors are theoretically described. Then the thesis deals with the design of the new curcuit structures with nonlinear components, which comes out from the former known realizations. Several possible solutions of the examined circuit have been designed and the most convenient structure has been selected. The chosen solution has been thoroughly analysed in subsequent diploma thesis to enable comparison of the theoretically designed circuit with the practically realized one.
45

Řiditelné kmitočtové filtry s moderními aktivními prvky / Controllable Frequency Filters with Modern Active Elements

Preclík, Milan January 2010 (has links)
The work deals with design of transformation cells suitable for realization of higher orders frequency filters with possibility of cutoff frequency control. At first, there is a common description of frequency filters and active elements like current and voltage conveyors. Furthermore assumptions of cutoff frequency control are defined which result in a convenient characteristical equation. Phylosophy of synthetic elements DP , EP , DS , ES including a possibility of change of cutoff frequency is next in line. By exploitation of synthetic elements theory new circuit’s schemes of transformation cells are searched. The work continues with the choice of appropriate transformation cells for resulting circuit’s solutions of frequency filters with possibility of cutoff frequency control by using transfer coefficients of active elements or with help of passive elements. The work concludes with verification of its proper function based on a simulation executed in OrCAD and with practical implementation of choosen circuit’s solution.
46

Všestranné autonomní obvodové ekvivalenty plovoucích a uzemněných pasivních prvků / Versatile autonomous circuit equivalents of floating and grounded passive elements

Štěpán, Radim January 2011 (has links)
This thesis deals with a proposal of versatile autonomous circuit equivalents of floating and grounded passive elements by means of modern active tectonic blocks, such as current and voltage conveyors of all three generations. Current conveyors range as essential tectonic blocks in a current mode. Concerning signal processing, it encompasses a mixed tectonic block. In most cases, these elements may be substituted for presently insufficient operating amplifiers. The voltage conveyor was defined on the basis of duality of current and voltage modes. This element could be selected as a suitable active component for circuits operating in a voltage mode. Implementing the connection, a general autonomous circuit is taken into account. By selecting given admittances, a FDNR (floating frequency dependent negative resistance) element, floating capacitance, floating inductance and ground to floating admittance converter may be implemented. The practical part describes connections which fulfill given requirements. The suggested elements are simulated in comparison with ideal elements and subsequently, they are applied to a frequency filter. The second order filter with a proposed induction coil was practically assembled and experimentally measured in a laboratory. The measured results were compared to simulations received by the use of ideal and real models of current and voltage conveyors.
47

Pohon pásového dopravníku pro transport uhlí / Drive of coal transport belt conveyor

Kliš, Kamil January 2013 (has links)
This diploma thesis deals with designing a drivetrain for a coal belt conveyor. Thesis contains necessary calculations according to norms needed for determining suitable components of a belt conveyor. The goal of this diploma thesis was to design a drivetrain for a belt conveyor, all its components including a frame of the drivetrain and to create drawing documentation.
48

Pásový dopravník přestavitelný / Adjustable belt conveyor

Drápalík, Martin January 2015 (has links)
The aim of this thesis is to design a conveyor belt readjustable to transport brown coal according to specific parameters. The introduction is focused on describing and dividing conveyor belts and characterizing their individual parts. The main part of the thesis is a description of selected components and design solutions, a functional computation carried out in accordance with the standard ČSN ISO 5048 and further an analysis of transported material's properties. The drafting documentation is attached to the thesis.
49

Robotizované pracoviště pro ukládání 25 kg pytlů maltové směsi na paletu / Robotic workstation for storing 25 kg bags of mixture per pallet

Falta, Libor January 2014 (has links)
The aim of this thesis is to create the design of a robotic workstation (RWS) for storing bags on a pallets with a capacity of 600 bags per hour. As an introduction to the issues of solved task, the introductory part of the thesis deals with a general information about industrial robots, theories ofdesigning RWS and palletization. For the suggested workstation it is given to have one pickup place from the roller conveyor and two unloading places. Within the RWS it is used belt, roller and chain conveyors as a peripheral device for conveying bags and pallets. There are two variants of RWS created for the possibility of technically - economic assessment. Solution for the security and the ergonomy of the workplace are an integral part of the study. Selected components of RWS have their risk analysis carried out. There is also the draft of a robot gripper mentioned, including assembly drawing. In conclussion there is calculation of returning of funds invested in the construction of RWS. Drawings of robotized workplace disposition, schemes of pneumatic and electrical connections and block diagram of the control system of RWS are included as attachments.
50

Analogové funkční bloky fraktálního řádu / Analogue fractional-order function blocks

Salášek, Jan January 2016 (has links)
Thesis describes the design of the blocks of fractional-order filters approximation using a filter of higher order integer. Active filters of third-order are use to create filter of 1+alfa -order, where alfa is between zero to one. One of the filters is practically implemented and measured.

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