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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

Effekter av ökad transfer time limit för tandimplantat.

Annika, Strömberg January 2021 (has links)
Nobel Biocare is one of the world’s leading companies that produce dental implants. This thesis was executed at the part of the company located in Karlskoga, Sweden.To be sure that the implants manufactured at Nobel Biocare will heal as good as possible when being implanted in a patient, the implant has to go through a coating process where the implants, after a few preparing steps, are going through a salt treatment. This salt treatment will in the end simplify the healing process for the patient. Between every process there is a time limit for how long the implants may rest, a so-called transfer time limit. This time is too short and leads to unnecessary cassations.The purpose of the thesis was to investigate what will happen if the transfer time limit of today increases from eight hours to sixty hours. What will be crucial for the results of the thesis is wether any contamination will occur on the surface of the dental implant or not.To investigate if any possible contamination occurs during the longer transfer time limit the implants were, after a coating process, examined with the help of a laboratry in Great Britain, where XPS analysis of different materials are performed.This thesis has the limitations of examining only the product TiUltra and has only investigated the longer transfer time limit during the coating process of the implants.The result of the thesis is that no contamination occured on the surface, and therefore there now is a basis available for technical documents to increase the transfer time limit from eight hours to sixty hours. This could also be implemented in other areas of the production, where there are similar problems. This thesis could be the base of new test plans for those areas. / Nobel Biocare är ett av de världsledande företag som tillverkar tandimplantat. Examensarbetet genomfördes hos den del av företaget som ligger i Karlskoga.För att de implantat som Nobel Biocare tillverkar ska läka så bra som möjligt när de väl är inopererade hos en patient genomgår dessa implantat en ytbehandling där ett saltlager, efter ett antal förberedande steg, läggs på ytan, som i slutändan förenklar läkeprocessen för den patient som får implantatet inopererat. Mellan varje processteg finns en tidsbegränsning för hur längre implantaten får vila, en så kallas transfer time limit. Denna tid är i dagsläget för kort och leder till onödiga kassationer.Syftet med examensarbetet var att undersöka vad som händer om den satta transfer time limit ökas från åtta timmar till 60 timmar. Det som kommer vara avgörande för resultatet är om någon kontaminering på ytan av implantaten uppstår eller inte.För att undersöka om eventuell kontaminering uppstod under en längre transfer time limit har de implantat som genomgått ytbehandlingsprocessen undersökts med hjälp av ett laboratorium i Storbritannien som utför XPS-analyser av olika material.Arbetets avgränsning är satt till produkten TiUltra och ska enbart undersöka en ökad transfer time limit under ytbehandlingsprocessen av implantaten.Resultatet av arbetet blev att ingen kontaminering uppstod på ytan och därmed finns tekniskt underlag för att kunna öka transfer time limit från åtta timmar till 60 timmar. Detta är något som skulle kunna implementeras på fler ställen i produktionen där liknande problem finns. Då skulle detta arbete och dess upplägg för test av förlängd transfer time limit kunna ligga som underlag för planeringar av nya tester.
2

Štúdium chemických procesov v atmosférach exoplanét / Study of Chemical Processes in Exoplanetary Atmospheres

Chudják, Stanislav January 2017 (has links)
In the present work, the abnormal glow discharge at atmospheric pressure was generated in the nitrogen-methane (1 to 5 %) gaseous mixtures related to the atmosphere of Titan. The discharge itself was monitored by optical emission spectrometry that confirmed presence of active nitrogen species and various radicals formed from methane. Besides them, the CN spectral bands were observed. Intensities of all light emitting species were studied in the dependence on applied power and composition of nitrogen-methane mixture. The rotational temperature of about 2000 K was calculated from the second positive nitrogen system. The vibrational temperature also obtained from neutral nitrogen molecule increased nearly directly with methane from 3000 K (1 % CH4) to 3600 K (5 % CH4). In the contrary, vibrational temperature obtained from nitrogen molecular ion decreased with methane in the gaseous mixture and increased with applied discharge power from 3700 K to 4200 K. The same trend showed the vibrational temperature calculated from violet system of CN with value from 4600 K to 5800 K. The stable discharge products were analysed by proton transfer time of flight mass spectrometry of the exhausting gas. Presence of many aliphatic and some aromatic hydrocarbons was confirmed as well as quite a lot of amino and cyano compounds. Increasing concentrations of methane have produced more substances with higher molecular weight and less simple substances that were likely to be consumed on more complex substances. Their relative intensities were determined under the same conditions as optical emission spectra were collected.
3

Projekt komunikace distančních ochran 7SA 610 pro chránění přenosového vedení / Project of Communication for Distance Protections 7SA 610 Protecting a Transmission Line

Bartko, Jan January 2011 (has links)
This work describes the structure and function of the distance protection relay Siemens 7SA610 SIPROTEC and presents the basic theoretical knowledge of the communication standard IEC 61850 at the beginning. It focuses on the configuration of the topology of two 7SA610 distance protection relays, PC and secondary relay test set Omicron CMC256 +. These two distance protection relays were programmed by using software implement DIGSI to transmit and receive GOOSE messages. It served to testing this created network by simple function. Computer and tester simulated the control system and commanded auto-reclosure to the first distance protection. Instruction was processed and also sended to the second distance protection. The final objective was to measure the tranfer time of GOOSE message between two distance protection relays. There was used a secondary tester. This measurement was implemented the tester Omicron CMC 256 +, which involves extending the NET-1 and so is compatible with the standard IEC 61850. The results and further actions are summarized in conclusion.
4

A Methodology for Identifying Inconsistencies Between Scheduled and Observed Travel and Transfer Times using Transit AVL data: Framework and Case Study of Columbus, OH

Wang, Yuxuan January 2020 (has links)
No description available.
5

Preemption strategy for traffic signals at intersections near highway-railroad grade crossings

Cho, Hanseon 30 September 2004 (has links)
Because the operational characteristics of signalized intersections near highway-railroad grade crossings (IHRGCs) are different from those of signalized intersections located elsewhere in the traffic system, standard operational strategies do not apply. This is because safe operation at IHRGCs takes precedence over all other objectives. Because the prime objective of the current preemption methods is to clear the crossing, secondary objectives such as safe pedestrian crossing time and minimized delay are given less consideration or ignored completely. Consequently, state-of-the-practice strategies may cause serious pedestrian safety and efficiency problems at IHRGCs. Therefore, there is a definite need for research on how to improve traffic signal preemption strategies. An important element of preemption strategy is detection of trains and prediction of arrival times. However, because of the limitations of current detection technologies, estimation algorithms, etc., there is a wide range in these warning times. In this dissertation, a new train-arrival prediction algorithm was developed using detection equipment located farther upstream from the HRGC. The state-of-the-art transition preemption strategy (TPS) was developed to ensure that as preemption is initiated by approaching trains, the signal display does not change in a manner that endangers either pedestrians or drivers. However, because it does not account for the variability of predicted train arrival times, there is still a possibility of failure. Therefore, a new transition preemption algorithm that is specifically designed to improve intersection performance while maintaining or improving the current level of safety is developed. This dissertation developed a preemption strategy (TPS3) that uses better train arrival time estimates to improve the safety and efficiency of IHRGCs. The approach was simulated on a test bed in College Station, Texas, and it was concluded that the new TPS improves the safety and operation of intersections near highway-railroad grade crossings.
6

Estimation et modélisation de paramètres clés des capteurs d’images CMOS à photodiode pincée pour applications à haute résolution temporelle / Estimation and modeling of key design parameters of pinned photodiode CMOS image sensors for high temporal resolution applications

Pelamatti, Alice 17 November 2015 (has links)
Poussée par une forte demande et un marché très compétitif, la technologie PPD CIS est en évolution permanente. Du fait de leurs très bonnes performances en terme de bruit, les capteurs d’image CMOS à base de Photodiode Pincée (PPD CIS) peuvent désormais atteindre une sensibilité de l’ordre de quelques photons, ce qui rend cette technologie particulièrement intéressante pour les applications d’imagerie à haute résolution temporelle. Aujourd’hui, la physique des photodiodes pincées n’est pas encore comprise dans sont intégralité et il y a un manque important d’uniformisation des méthodes de caractérisation de ces détecteurs. Ces travaux s’intéressent à la définition, à la modélisation analytique, à la simulation et à l’estimation de paramètres clés des PPD CIS, tels que le temps de transfert, la tension de pincement et la full well capacity (FWC). Comme il a été mis en évidence par cette thèse, il est de première importance de comprendre l’effet des conditions expérimentales sur les performances de ces capteurs. Ceci aussi bien pour l’optimisation de ces paramètres lors de la conception du capteur, que lors de la phase de caractérisions de celui-ci, et enfin pour choisir correctement les conditions de mesures lors de la mise en œuvre du dispositif. / Driven by an aggressive market competition, CMOS Image Sensor technology is in continuous evolution. Thanks to the outstanding noise performances of Pinned Photodiode (PPD) CIS, CMOS sensors can now reach a few photons sensitivity, which makes this technology a particularly interesting candidate for high temporal resolution applications. Despite the incredibly large production volume, today, the PPD physics is not yet fully understood, and there is still a lack of golden standards for the characterization of PPD performances. This thesis focuses on the definition, analytical modeling, simulation and estimation of PPD key design parameters, with a particular focus on charge mechanisms, on the pinning voltage and on the full well capacity. The models developed in this work can help both manufacturers and users understanding the design trade-offs and the dependence of these parameters from the experimental conditions, in order to optimize the sensor design, to correctly characterize the image sensor, and to adjust the operation conditions to reach optimum performances.

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