• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 94
  • 82
  • 17
  • 13
  • 1
  • 1
  • Tagged with
  • 208
  • 124
  • 20
  • 18
  • 16
  • 16
  • 14
  • 12
  • 12
  • 11
  • 11
  • 11
  • 11
  • 10
  • 10
  • 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.
71

Modelagem e automação em nova técnica de medida para relações de água e planta / not available

Bertucci Neto, Victor 29 April 2005 (has links)
A água realiza diversos papéis, físico, estrutural, e metabólico em plantas superiores. Entretanto, a maior parte da água tomada pelas plantas através do solo é transpirada para a atmosfera. As plantas reciclam mais da metade do volume de chuva anual da Terra. A força que direciona a água captada pelo solo para cima é dada pela diferença de potencial químico entre o solo e a atmosfera. No entanto, os mecanismos que ocorrem quando a água sobe a planta contra a gravidade ainda são objetos de discussão. Durante as últimas três décadas tem sido usada a sonda de pressão para medir relações de água com plantas superiores. Esta técnica fornece acesso direto a muitos parâmetros biofísicos que controlam as respostas de curto e longo período em relação à água e a deficiência de sais no ambiente. Basicamente é usado um capilar preenchido com óleo e após a punção da célula vegetal o movimento do menisco no capilar é medido e controlado. Alguns esforços foram feitos para elaborar um instrumento que automatizasse a medida. Não foi observado na literatura nenhum artigo com uma descrição mais detalhada deste instrumento. Com o objetivo de contribuir nesta área, segundo a linha de desenvolvimento, neste trabalho é apresentada uma nova técnica, a sonda termoelástica, baseada na compensação térmica da pressão. Com esta nova técnica podem ser medidos valores de pressão negativa abaixo daqueles obtidos com a sonda de pressão. Visando preencher a lacuna existente entre a teoria e a prática, são apresentados modelos para ambos instrumentos. Estes modelos são adequados para a análise e síntese de controladores. Alguns resultados experimentais sobre a sonda termoelástica são apresentados e discutidos, incluindo um sistema que controla a posição do menisco no capilar e mede a pressão aplicada na ponta do capilar. / Water plays diverse physical, structural and metabolic roles in higher plants, but most of the water taken up by plants from the soil is transpired to the atmosphere. Plants recycle more than half of the annual rainfall on land. The overall driving force for water lifting in plants is ultimately the chemical potential difference of water between soil and atmosphere. However, the mechanisms by which water rise against gravity occurs are still controversially discussed. During the last three decades has been used a pressure probe technique to measure water relations of higher plants. This technique provides direct access to many biophysical parameters which control the short and long-term responses of plant cells to water and salt stress in the environment. Basically, it is used a capillary filled with oil and after the puncture of the plant cell the movement of the meniscus is measured and controlled. Some attempts were made in order to perform an automatic measurement. It was not found in the literature a detailed description about this instrument. Following this development, this work presents a new technique, a thermoelastic probe, based on thermal compensation of pressure. By means of this new technique it can be measured negative pressures below of that it was obtained with a classical pressure probe. In order to fill the lack between the theory and the practice, it is also presented a model for both the pressure and the thermoelastic probe. These models are suitable for control systems synthesis and analysis methods. Also, experimental results on the thermoelastic probe are presented and discussed, including a system that measures the pressure applied at the tip of the capillary by controlling the meniscus position of the probe.
72

Měření pozice elektronickými dotykovými sondami / Position measurement by electronic contact probes

Noga, Kamil January 2018 (has links)
This work is dealing with custom screens programming for Mitsubishi M7 series controller. These custom screens will be working as graphic user interface for easy workpiece zero position measuring and also for precise measuring of length and diameter of tools used for working on the work piece.
73

Návratový modul aerologické sondy / Aerologic Probe Return Module

Malalan, Nina January 2020 (has links)
Metody, jak získat zpět měřicí vybavení pro průzkum horní atmosféry, jsou v současné době značně omezené. Velmi nízká míra návratnosti vedla k návrhu radiosondy na jedno použití, což nutí mnoho světových meteostanic omezit počet provedených denních měření. Snížení frekvence sondáže pak následně vede ke snížení přesnosti předpovědi počasí. Tato práce otevírá cestu k alternativě v podobě konstrukce návratového modulu, který by měl zajistit řízené vyklesání aerologické sondy a přistání na vhodném místě. Zvolená konstrukce je výsledkem analýzy možných konfigurací, jejichž cílem bylo najít nejoptimálnější variantu pro splnění požadavků mise. Konvenční konfigurace s pevnými křídly je zde sledována zkoumáním jejích základních částí. Zvolené součásti jsou dimenzovány na základě dvou krokových iteračních metod detailně popsaných v této práci. Dále jsou zkoumány základní požadavky na autonomii návratového kluzáku. Je zde navržena koncepce řídicího systému, který by měl vybrat nejvhodnější a dostupné místo pro přistání a navést kluzák k přistání na něm. V neposlední řadě jsou analyzovány a zvažovány možné metody instalace užitečného zatížení a studovány a porovnávány možné systémy odpojení od meteorologického balónu. Popsaný návratový modul by měl ve výsledku umožnit častější provádění měření atmosféry s přesnějšími měřicími zařízeními u kterých bude předpoklad vysoké pravděpodobnosti opakovaného použití. Očekává se, že tento přístup by měl vést ke snížení nákladů na sondáž atmosféry a zároveň zredukovat množství použitého materiálu a produkovaného odpadu.
74

Použití měřících sond (nástrojové a obrobkové) pro stroje z produkce TOS KUŘIM / Using measuring probes ( for tools and workpieces) for production machine of range of products firm TOS KUŘIM

Kohút, Josef January 2011 (has links)
The purpose of this dissertation is to familiarize the reader with basic recognition of machine measuring probes for tools and workpieces. Namely then in area of measurement on CNC machining centers. Both recognition from aspects of principle of function of sensing elements and type of transmition to control system, and recognition from constructional aspects are described here. Further it puts mind on equipment of machine probes (touches etc.) and rules for best selection of this equipment. Next part of this work describes selection of appropriate probes, for universal machines from production of firm TOS Kuřim. Last part deals with testing of designed measuring system for concrete machine from production of firm TOS Kuřim. His typical composition, evaluation of tests results and achieved accuracy is also described here.
75

Programové moduly automatického nastavování nástrojů u soustružnických center / Creating of SW modules for setting of lathe tools using no contact laser measuring device

Rolenc, Martin January 2011 (has links)
Creating of SW modules for setting of lathe tools using no contact laser measuring device This master´s thesis is about possibilities of using touch probes, especially tool probes. Theoretical part of thesis is about principles, which probes use for their function, and about possibillities of application. Practial part is devoted creating sw modules for semiautomatic tool control for NC turning machine
76

Management kalibrace souřadnicového měřicího stroje (SMS) / Calibration management system of measuring machine (CMM)

Lysý, Zbyněk January 2012 (has links)
This diploma thesis with title of „Management of Coordinate Measuring Machine Calibration“ aimed to develop detailed analysis of uncertainties when deploying 3D coordinate measuring machine MicroVu Excel in practice. The analysis was supported by an example of measuring uncertainty calculation. This thesis also discusses the integration of automatic assessment of uncertainties into programming equipment; and creation of methodical calibration process for this kind of machine.
77

Zařízení pro měření proudění vzduchu pod vozidlem / Device for measurement the air flow under the vehicle

Šilar, Josef January 2015 (has links)
The target of this thesis is construction design of a device for measuring flow bellow a vehicle. To deep dive into the problem first there is theory of driving resistance, flow and aerodynamics followed by the practical part. Also it solves completion of CFD model to detect flow field bellow vehicle while using this device.
78

Optimalizace modelu vodní elektrárny / Optimization model of hydropower plant

Kršiak, Oliver January 2016 (has links)
This diploma thesis deals with the creation measuring instruments and program for controlling model hydropower plant intended for laboratory use. The first step is to improve the mechanical performance of the original model of hydroelectric power. The second step is to select a revive measuring instruments for electric values of the plant. The third step is to create a program for displaying electrical parameters and control the plant. The final step was re-measuring the operating characteristics of the generator model hydropower plant.
79

Studium exprese MDR pump u kvasinek Saccharomyces cerevisiae za různých růstových podmínek: metoda s fluorescenční sondou diS-C3(3) / Studium exprese MDR pump u kvasinek Saccharomyces cerevisiae za různých růstových podmínek: metoda s fluorescenční sondou diS-C3(3)

Zahumenský, Jakub January 2011 (has links)
In this work, we studied two yeast ABC transporters, Pdr10p and Pdr15p. At the time of assignment of this thesis, it was believed that these proteins contribute to the yeast MDR phenotype (PDR) on the grounds of their high homology to another yeast MDR protein, Pdr5p. In order to study these pumps, two sets of isogenic null-mutant strains were prepared with all possible combinations of gene deletions. We report that both of the studied proteins are very important in sus- taining the normal plasma membrane microenvironment for the most abundant, and essential, yeast plasma membrane protein, H+ -ATPase and so influence the membrane potential. Pdr10p and Pdr15p thus play an as yet unknown role in reg- ulation of the activity of this enzyme. Furthermore, we report that deletion of the genes coding for these proteins severely reduces the ability of the H+ -ATPase to be activated by the protonophore CCCP which is a weak acid. Studies performed with immunosuppressant FK506 further show that this compound reduces the viability of S. cerevisiae mutant strain PLY643 lacking genes coding for Pdr5p, Snq2p and Yor1p. Further deletion of Pdr10p and Pdr15p does not increase the lethality of this compound. Neither CCCP nor FK506 are substrates of the stud- ied pumps. 1
80

Experimentální a teoretické studium využití sondových metod pro diagnostiku plazmatu / Experimental and theoretical study of utilization of probe methods for plasma diagnostics

Peterka, Matěj January 2014 (has links)
The ball-pen probe is a unique probe recently developed at the Institite of Plasma Physics in Prague. It has been designed for direct measurement of plasma potential at the CASTOR tokamak. Nowadays, it is used routinely at several tokamaks in Europe, and the first tests in low-temperature plasma have also already been performed. The aims of the thesis are primarily experimental. A ball-pen probe has been constructed from available materials, which is suitable for systematic measurements of radial profiles in the low-temperature plasma of a cylindrical magnetron. By means of comparison to other diagnostics, it was proved that ball- pen probe is able to directly measure plasma potential in a certain range of plasma parameters even though its current-voltage characteristic is not symmetric, which is in contradiction with the simplified theory for ball-pen probe. Powered by TCPDF (www.tcpdf.org)

Page generated in 0.0354 seconds