• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 315
  • 52
  • 50
  • 30
  • 8
  • 6
  • 2
  • 1
  • 1
  • Tagged with
  • 466
  • 196
  • 98
  • 81
  • 55
  • 45
  • 45
  • 43
  • 39
  • 38
  • 37
  • 33
  • 31
  • 29
  • 29
  • 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.
321

Systém pro správu bezdrátových zobrazovacích modulů s využitím technik získávání energie / System for Management of Wireless Display Modules Using Energy Harvesting Techniques

Veselý, Miroslav January 2021 (has links)
This master thesis is focused on smart display modules and their management. Attention is paid on analysis of the current state with focus on power supply and remote management. The goal of this master thesis is to design and develop a prototype of a wireless display module and management system on the base of gained knowledge. A substantial part of this thesis is also a base station which allows remote access to network with wireless display modules and management.
322

Analýza vlivu převodového ústrojí na tahový výkon traktoru / Analysis of powertrain impact on pull power capacity of a tractor

Zicha, Marek January 2017 (has links)
This diploma thesis “Analysis of powertrain impact on pull power capacity of a tractor” is focused on evaluation of measured data gained from performance testing of tractors Claas Arion 640 for two different types of transmission. There are also discussed the measuring methods and there is detailed described the function of measured transmissions.
323

Moderní metody bezsnímačového řízení pohonů s PMSM motorem / Novel Methods of Sensorless Control of Drives with PMSM Motor

Lepka, Jaroslav January 2018 (has links)
Purpose of this dissertation is to explore control techniques of PMSM motors and the design of a complex solution of sensorless control across a wide range of speed and torque. The proposed solution supports industrial implementation of different types of end equipment which use a PMSM motor. The work covers a thorough analysis of position and speed estimation. The Control structure is based on field oriented control technique, processes estimated quantities, and optimizes motor conditions to achieve maximum efficiency, start-up torque, and speed. The work discusses how the solution complies with the latest IEC standards. Compliance with these standards requires adapting the sensorless control technique and field oriented control structure. The elimination of a rotor position sensor and a temperature sensor measuring winding temperature requires development of techniques in software for blocked rotor detection and overload detection. The proposed solutions, which have been granted US patents, are explained in this work and utilize the unique features of an NXP microcontroller optimized for motor control applications. The achieved results are demonstrated on real industrial applications.
324

Vliv mnohonásobného zatěžování na vybrané parametry lehkého betonu / Influence of multiple cyclic loading on the selected parameters of lightweight concrete

Alexa, Martin January 2018 (has links)
The diploma thesis deals with the observation of the values of selected parameters (especially the static modulus of elasticity) of light-weight concrete in compression before and after multiple cyclic loading. The deformation of test specimens during multiple cyclic loading were measured with resistive strain gauges. Test specimens (cylinders with a diameter of 150 mm and height of a 300 mm) were cyclically loaded and up to 4 500 loading cycles were performed. The aim of this thesis is assessment changes in the values of static modulus of elasticity depending on the number of loading cycles.
325

Stanovení modulů pružnosti směsí pro podkladní vrstvy vozovek / Determination of elasticity modulus for base layers

Hepner, Urban January 2018 (has links)
The thesis deals with the experimental determination of the resilient modulus using cyclic triaxial test with the selected unbound mixtures of the base course of the pavement. The aim is to verify whether the proposed modulus-resilient in the regulation TP 170 based on the statisticaly verified data dating several decades ago is still valid in the present. Furthermore, the thesis deals with the dependence between the measured and the calculated values of the modulus resilient Mr from the cyclic triaxial test and the California Bearing Ratio tests. For the classification of the selected materials, further tests are used in the thesis, such as granularity and compaction tests.
326

Vliv etherů celulózy na reologické vlastnosti vápna / Influence of cellulose ethers on rheological properties of lime

Hegrová, Michaela January 2018 (has links)
The subject of this diploma thesis is a study of the influence of cellulose ethers on the rheological properties of lime. The theoretical part focuses on rheological parameters, techniques and test equipment used in rheology measurements. Various types of cellulose ethers and their influence on the rheological properties of fresh mortars are described. The practical part deals with the study of the influence of different types and quantities of cellulose ethers on the properties of fresh lime pastes and mortars. The results were obtained from measurements on a rotational rheometer with a special geometry for building materials. Measuring methods used were flow and oscillatory tests. Yield stress, viscosity and flow index were determined by the flow measurement. The stability and stiffness of fresh materials were determined during the oscillation measurements. The measured results are then evaluated and compared.
327

Funkční zkoušky na směsích zkušebního úseku s asfaltovým betonem s vysokým obsahem R-materiálu / Functional tests on mixtures of the test section with asphalt concrete and high amount of RAP

Kučerová, Marcela January 2018 (has links)
The diploma thesis is focused on the testing of asphalt mixtures of asphalt concrete containing reclaimed asphalt and laying of the test section. The theoretical part deals with the use of reclaimed asphalt in hot asphalt mixtures, namely the specifics of rejuvenating agents, aging and asphalt mixture. Further more information on the functional properties of asphalt mixtures and the influence of reclaimed asphalt on them is given. The practical part describes testing of mixtures of ACO 11+ and ACO 11+ with 50% reclaimed asphalt and tests on asphalt binders. In order to compare the proposed mixtures, the low thermal properties of ČSN EN 12697-46 and the stiffness modules according to ČSN EN 12697-26. In the last part of the diploma thesis the results of the measured values were compared with each other in order to determine of asfphalt recovery. From the overall test results, it can be seen that the effect of the rejuvenating agent was positive. However, the desired degree of rejuvenation has not been achieved after production.
328

Bezdrátový kontrolér pro dálkové ovládání PTZ kamer / Wireless system for remote control of pan–tilt–zoom cameras

Chýlek, Richard January 2013 (has links)
This semestral project is concerned with remote control PTZ camera using the wireless controller, and the controller design including design documents. The controller will be composed of the signal converter, microcontroller and RF module. Control data to the controller will come via link RS485 and controller will be able to communicate using the following protocols-Ernitec and Pelco. The proposed controller, according to data from the manufacturer to have a range of up to 500m. This parameter and also other transmission parameters confirm in the diploma thesis which will focus the actual implementation of the controller.
329

Návrh rotujícího usměrňovače pro synchronní generátor / Design of rotating rectifier for synchronous generator

Skurka, Tomáš January 2018 (has links)
This diploma thesis is focused on the design of a rotating rectifier for a synchronous generator. Based on defined requirements, the new rotating rectifier concept has been created that allows a greater current range than existing rectifier used by Siemens Electric Machines s.r.o. The thesis is divided into five parts. The first part deals with the search of existing rotating rectifiers and other design possibilities. The requirements for the rotating rectifier were defined in the second part of the thesis. The following section deals with both electrical design of rectifier elements and varistors. The fourth part of the diploma thesis describes the thermal analysis. On the basis of thermal analysis the operating conditions of the rotating rectifier were determined. The last part of the thesis is devoted to mechanical and modal analysis. Based on these analyses, the strength and operability of the new rotating rectifier concept were verified.
330

Vliv rychlosti rázového zatěžování na napjatost, deformaci a spolehlivost komponenty palivového systému automobilu / Effect of Velocity of Impact Loading to Stress, Deformation and Durability of Component of Fuel Car System

Dobeš, Martin January 2018 (has links)
Passive safety is a well-known term. This term can be further categorized into different topics of the car passive safety, restraint systems, safety assistants (ABS, ESP, ASR, etc.). One of these topics is passive safety of the fuel system. Safety and tightness of the fuel system must be guaranteed even under non-standard conditions, for example a collision against a fixed obstacle. This issue is not often mentioned in the field of car safety. It is considered a standard. Passive safety of the fuel system is often ensured using various interesting technical solutions and devices, usually patented ones. The development of these solutions is supported by numerical simulations in different stages of development process. The doctoral thesis deals with impact loading of the plastic components of the fuel system, in particular Fuel Supply Module (FSM), which is mounted inside the fuel tank. The flange is the most important part of the fuel supply module from the car safety point of view. The flange closes FSM on the external side of the fuel tank. The thesis focuses on the finite element analysis of the complete or partial FSM, and the flange itself during impact loading. The main objective of this thesis are numerical material models, taking into account important aspects of the mechanical behavior of polymer materials during impact loading. There are a lot of ad hoc invented or standardized experiments described in this thesis. These experiments are used for estimation of the material parameters or comparison of numerical analysis vs real conditions, or tests. The solver LS-DYNA was mainly used for numerical simulations. The final results of this thesis brings new quantified knowledge about behavior of the Typical Semi-Crystal Polymer (TSCP), not only for impact loading. The practical part of this thesis defines new methodology for the numerical simulation approach of impact loading for FSM. This methodology is directly usable for new product development. A lot of numerical material models were developed and tested. The best results were achieved using numerical material model *MAT_24 with combination of *MAT_ADD_EROSION card. The limits and parameters for this numerical material model was estimated empirically during conducting experiments. The numerical material model SAMP-1 was partly solved in this doctoral thesis, but more detail study will be given in future works.

Page generated in 0.0273 seconds