• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 13
  • 8
  • 4
  • 3
  • 2
  • 1
  • 1
  • Tagged with
  • 34
  • 5
  • 4
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 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.
31

FJÄRRSTYRD SANERINGSROBOT UTVECKLAD MED CODESYS FÖR RASPBERRY PI / Remote-controlled decontamination robot based on CODESYS for Raspberry Pi

Eskilsson, Hampus January 2020 (has links)
Vid institutionen för tillämpad fysik och elektronik, Umeå universitet, bedrivs utbildning och forskning inom bland annat automation och robotik. Syftet med projektet är att skapa en robot där rapporten skall kunna användas för att förenkla framtida utlärningar inom de ämnen projektet tar upp. Projektets mål är att designa, skapa och programmera en saneringsrobotprototyp med hjälp av utvecklingsgränssnittet CODESYS. För att möjliggöra sanering används UVC-ljus. UVC är en kategori inom UV-ljus där endast ett spann av våglängder innefattas, vilka bevisats ha bakteriedödande effekt. Robotens design är ritad i CAD och är måttanpassad utefter den hårdvara som används. Vidare består robotens chassi av två plexiglasplattor som laserskärs med färdiga hålbilder. Chassit sätts ihop med hjälp av sex M6-gängstänger, vilket skapar två plan där komponenter kan skruvas fast i de laserskärda hålbilderna. Roboten använder sig av motorstyrningskort, servomotorer och mecanumhjul där styrning sker med hjälp av två stycken joysticks. Joysticksen i samband med teoretiska rörelseekvationer möjliggör omnidirektionell rörelse. Vidare används ett reläkort för styrning av både UVC-lampor och signallampa. Roboten programmeras i CODESYS som ett ”Function Block Diagram” (FBD) där en mängd nya programbibliotek blir implementerade. Genom användning av CODESYS visualiseringsverktyg skapas ett användargränssnitt som gör att roboten kan fjärrstyras via ett webbgränssnitt. Projektet uppnådde sju av åtta krav från kravspecifikationen vilka validerades via fem uppsatta testscenarion. Resultatet är en robot som kan styras i valfri riktning via WiFi genom exempelvis en smartphone. Reläets olika portar öppnas och stängs genom programmerade funktioner, knappar och en IR-sensor vars uppgift är att avläsa kroppslig värme. Vid fortsatt utveckling av roboten skulle en kamera kopplats in och använts i HMI-gränssnittet, vilket hade möjliggjort telestyrning. Fler styrningsalternativ hade också kunnat implementerats, exempelvis genom att lägga till en knapp som gör att roboten roterar 90 grader. / At the Department of Applied Physics and Electronics, at Umeå University, education and research are conducted in areas such as automation and robotics. The purpose of the project is to create a robot, where the report can be used to assist future learning within the subjects covered by the project. The goals of the project are to design, create and program a decontamination robot prototype using the development interface CODESYS. UVC-light will be used to achieve this sanitation. UVC is a category of UV light which includes a limited range of wavelengths, that have been shown to have bactericidal effect. The robot is designed in CAD using the measurements of the hardware used. Furthermore, the robot's chassis consists of two plexiglass plates that are laser cut according to predetermined hole patterns. The chassis is assembled using six M6 threaded rods. The design constitutes two levels onto which the components can be mounted. The driveline consists of motor control boards, servomotors and mecanum wheels. Two joysticks are used to control the steering of the robot. The joysticks in relation with theoretical equations enables omnidirectional motion. Furthermore, a relay card is used for controlling both UVC and the signal lamp. The robot is programmed in CODESYS as a "Function Block Diagram" (FBD) where several new program libraries are implemented. By using CODESYS’ visualization tool, a user interface is created where the robot can be remotely controlled via a web interface. Seven out of eight requirements were achieved in the project. The achieved requirements were all validated through five test scenarios. Furthermore, the robot can be steered in any direction via Wi-Fi through inter alia a smartphone. The various ports of the relay are controlled by programmed functions and buttons, which can be overridden in the case of body heat being detected by an IR sensor. If the robot were to be further developed, a camera could be connected and used in the HMI, which would have enabled distance remote control. Furthermore, several control options could have been implemented, for example a button that allows the robot to rotate 90 degrees.
32

Short wavelength UV–LED photoinitiated radical polymerization of acrylate–based coating systems—A comparison with conventional UV curing.

Torfgård, Olof January 2021 (has links)
The present work was performed at Sherwin–Williams Sweden group AB with the objective of comparing short-wavelength light emitting diodes (UVB/UVC) with the conventional mercury arc lamp as a curing method of acrylate-based, UV-paint undergoing free-radical polymerization when exposed to UV-radiation. Due to environmental and health risks, mercury-doped radiation sources will be phased out in the near future, according to the United Nations Minamata convention, hence new alternatives are needed. Light-emitting diodes differ from the mercury arc lamp as they provide semi-discrete output intensity lines within the UV spectrum instead of a broad output distribution with several main intensity lines. The power output is also considerably lower compared to the conventional method which limits the irradiance and dose that are key parameters in activating and propagating free-radical polymerization of UV-paint. Seven different light-emitting diodes between 260–320 nm was examinedand compared to the conventional mercury arc lamp. Cured coatings were evaluated by measuring the relative extent of acrylate conversion with ATR-FTIR and micro-hardness indentation test. Both methods correlate to the relative cross-linking density and qualitatively describe the curing process for each radiant source at a specific irradiance and dose. Three different paint formulations with widely different properties were used in the experiments. All three paints were able to cure with one or several light emitting diodes at comparable doses and 10 to 20 times lower irradiance to the conventional mercury arc lamp, resulting in similar acrylate conversion and hardness.
33

The Role of p53 and Hypoxia in Nucleotide Excision Repair

Dregoesc, Diana 12 1900 (has links)
The nucleotide excision repair (NER) pathway is essential for repair of UV-induced bulky DNA lesions. NER is divided into two subpathways: global genome repair (GGR) and transcription-coupled repair (TCR). UVC radiation has been shown to result in the formation of bulky DNA lesions, which are removed by NER. Previous published reports have shown a role for the p53 tumour suppressor protein in GGR and TCR, but the involvement of p53 in TCR has been controversial. In addition, it has also been suggested that hypoxia affects NER and expression of p53. In the present work, the role of p53, hypoxia and HIF-lα in NER was investigated. It was determined that p53 overexpression in primary human fibroblasts resulted in up-regulation of both the GGR and TCR subpathways of a UV -damaged reporter gene. Pre-treatment of cells with low UVC-fluence and p53 overexpression also induced an upregulation of GGR and TCR. These results are consistent with a p53-dependent upregulation of TCR and GGR of the UVC-damaged reporter gene, as well with a UV-inducible TCR and GGR that is dependent on p53 expression prior to UV treatment. Hypoxia coupled to low pH induced a transient up-regulation of p53 expression and NER in human primary normal fibroblasts and a concomitant decrease in UVC sensitivity. In contrast, in tumour cells hypoxia coupled to low pH resulted in a delayed, but not absent up-regulation of NER, which was p53-independent and did not result in a decrease in UVC sensitivity. We report here that it is the early transient p53-dependent up-regulation induced by hypoxia coupled to acidosis in human primary normal fibroblasts that may play a significant role in cellular UVC sensitivity. These data suggest a different cellular NER response to hypoxia compared to hypoxia coupled to low pH. The NER response to hypoxia and hypoxia coupled with acidosis was also different in primary cells when compared to tumour-derived cells. It was demonstrated that expression of dominant-negative HIF-lα in rat prostate tumour cells results in a reduction in host cell reactivation (HCR) of a UV-damaged reporter gene when compared to that in wild-type HIF-lα cells under normoxic conditions suggesting that basal HIF-lα expression may play an important role in NER. In addition we showed that hypoxia induced an up-regulation of NER in human primary normal fibroblasts that was delayed, but not absent in TCR-deficient CSB cells, suggesting a role for hypoxia in up-regulation of the GGR pathway of NER of a UVdamaged reporter gene. In contrast, HIF-lα-overexpression under conditions of hypoxia resulted in a down-regulation of NER in normal fibroblasts, which was delayed, but not absent in CSB fibroblasts. These results suggest that HIF-1α and CSB are involved in a hypoxia-induced NER response. This work provides further evidence that both GGR and TCR are p53-dependent. In addition, this study provides evidence that hypoxia and hypoxia coupled to acidosis can up-regulate NER in both primary and tumour cells, and that HIF-lα and the CSB protein play an important role in a hypoxia-induced NER response. / Thesis / Doctor of Philosophy (PhD)
34

Nové aktivní funkční bloky a jejich aplikace v kmitočtových filtrech a kvadraturních oscilátorech / Novel active function blocks and their applications in frequency filters and quadrature oscillators

Herencsár, Norbert January 2010 (has links)
Kmitočtové filtry a sinusoidní oscilátory jsou lineární elektronické obvody, které jsou používány v široké oblasti elektroniky a jsou základními stavebními bloky v analogovém zpracování signálu. V poslední dekádě pro tento účel bylo prezentováno velké množství stavebních funkčních bloků. V letech 2000 a 2006 na Ústavu telekomunikací, VUT v Brně byly definovány univerzální proudový konvejor (UCC) a univerzální napět'ový konvejor (UVC) a vyrobeny ve spolupráci s firmou AMI Semiconductor Czech, Ltd. Ovšem, stále existuje požadavek na vývoj nových aktivních prvků, které nabízejí nové výhody. Hlavní přínos práce proto spočívá v definici dalších původních aktivních stavebních bloků jako jsou differential-input buffered and transconductance amplifier (DBTA), current follower transconductance amplifier (CFTA), z-copy current-controlled current inverting transconductance amplifier (ZC-CCCITA), generalized current follower differential input transconductance amplifier (GCFDITA), voltage gain-controlled modified current-feedback operational amplifier (VGC-MCFOA), a minus-type current-controlled third-generation voltage conveyor (CC-VCIII-). Pomocí navržených aktivních stavebních bloků byly prezentovány původní zapojení fázovacích článků prvního řádu, univerzální filtry druhého řádu, ekvivalenty obvodu typu KHN, inverzní filtry, aktivní simulátory uzemněného induktoru a kvadraturní sinusoidní oscilátory pracující v proudovém, napět'ovém a smíšeném módu. Chování navržených obvodů byla ověřena simulací v prostředí SPICE a ve vybraných případech experimentálním měřením.

Page generated in 0.0268 seconds