858 resultados para measurement electronics


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A report is presented on the interesting bending effect of cladding mode resonances in fibre Bragg gratings (FBGs). It is observed that a serial of new cladding mode resonances can arise under bending and the new and the original cladding mode resonances have opposite trends in amplitude change and wavelength shift when the curvature varies. The discovery provides an effective new way to discriminate between bend and strain or bend and temperature when using only a single uniform FBG.

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A report is presented on the interesting bending effect of cladding mode resonances in fibre Bragg gratings (FBGs). It is observed that a serial of new cladding mode resonances can arise under bending and the new and the original cladding mode resonances have opposite trends in amplitude change and wavelength shift when the curvature varies. The discovery provides an effective new way to discriminate between bend and strain or bend and temperature when using only a single uniform FBG.

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Tässä diplomityössä on kehitetty kapeakaistaisten mikroaaltoresonaattoreiden mittaukseen soveltuvaa elektroniikkaa 400 MHz taajuusalueelle. Työn teoriaosuudessa on tutustuttu RF- ja mikroaaltotaajuuksilla käytettävien resonaattoreiden ominaisuuksiin sekä tarkasteltu erilaisia mahdollisia mittauselektroniikkatoteutuksia. Tarkastelujen perusteella on valittu toteutettavan mittauselektroniikan periaate. Toteutettu mittauselektroniikka hyödyntää suoraa digitaalista taajuussynteesiä hyvän taajuusresoluution saavuttamiseksi. Mittauselektroniikkaa on kehitetty prototyyppien avulla. Työssä on myös vertailtu resonaattoreiden mittaustuloksia käytettäessä kehitettyä mittauselektroniikkaa ja piirianalysaattoria. Kehitetyllä mittauselektroniikalla saadut tulokset vastaavat hyvin piirianalysaattorimittauksen tuloksia.

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Energian kulutuksen vähentäminen ja sen tutkiminen on kasvavan kiinnostuksen kohteena. Syntyneen lämmön mittaaminen on yksi tapa mitata energian siirtymistä. Lämpötilan mittaaminen on yleistä, vaikka usein on merkittävämpää selvittää missä ja miten lämpöenergia on siirtynyt. Tästä syystä tarvitaan lämpövuoantureita, jotka reagoivat suoraan lämpövuohon eli lämpöenergian siirtymiseen. Tässä tutkimuksessa suunnitellaan ja toteutetaan lämpövuoanturin mittauselektroniikka vaativaan käyttöympäristöön. Työssä käytettävän gradienttilämpövuoanturin tuottama jännitesignaali on mikrovolttiluokkaa ja ympäristön aiheuttama kohina voi olla huomattavasti suurempi. Tämän takia anturin tuottamaa signaalia on vahvistettava, jotta sitä voidaan mitata luotettavasti. Tutkimuksessa keskitytään vahvistimen suunnitteluun, mutta suunnittelussa on otettava huomioon koko järjestelmä. Anturin sähköiset ominaisuudet ja ympäristö asettavat rajoitteita vahvistimelle. Tavoitteena on selvittää miten voidaan mitata mikrovolttien jännitesignaalia mahdollisimman suurella taajuuskaistalla vaativassa käyttöympäristössä. Työn tuloksena syntyi mittalaite, jota voidaan käyttää vaativassa ympäristössä lämpövuon mittaamiseen. Suunnitteluparametrien mukainen vahvistus ja päästökaista sekä offset-jännitteen ryömintä saavutettiin suunnitellulla mittalaitteella, mutta offsetjännite ja kohina olivat hieman suunniteltua suuremmat. Mittalaitteella ja lämpövuoanturilla havaittiin selvästi lämpövuon muutoksia keinotekoisilla herätteillä.

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This paper proposes a three-stage offline approach to detect, identify, and correct series and shunt branch parameter errors. In Stage 1 the branches suspected of having parameter errors are identified through an Identification Index (II). The II of a branch is the ratio between the number of measurements adjacent to that branch, whose normalized residuals are higher than a specified threshold value, and the total number of measurements adjacent to that branch. Using several measurement snapshots, in Stage 2 the suspicious parameters are estimated, in a simultaneous multiple-state-and-parameter estimation, via an augmented state and parameter estimator which increases the V - theta state vector for the inclusion of suspicious parameters. Stage 3 enables the validation of the estimation obtained in Stage 2, and is performed via a conventional weighted least squares estimator. Several simulation results (with IEEE bus systems) have demonstrated the reliability of the proposed approach to deal with single and multiple parameter errors in adjacent and non-adjacent branches, as well as in parallel transmission lines with series compensation. Finally the proposed approach is confirmed on tests performed on the Hydro-Quebec TransEnergie network.

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Real-time viscosity measurement remains a necessity for highly automated industry. To resolve this problem, many studies have been carried out using an ultrasonic shear wave reflectance method. This method is based on the determination of the complex reflection coefficient`s magnitude and phase at the solid-liquid interface. Although magnitude is a stable quantity and its measurement is relatively simple and precise, phase measurement is a difficult task because of strong temperature dependence. A simplified method that uses only the magnitude of the reflection coefficient and that is valid under the Newtonian regimen has been proposed by some authors, but the obtained viscosity values do not match conventional viscometry measurements. In this work, a mode conversion measurement cell was used to measure glycerin viscosity as a function of temperature (15 to 25 degrees C) and corn syrup-water mixtures as a function of concentration (70 to 100 wt% of corn syrup). Tests were carried out at 1 MHz. A novel signal processing technique that calculates the reflection coefficient magnitude in a frequency band, instead of a single frequency, was studied. The effects of the bandwidth on magnitude and viscosity were analyzed and the results were compared with the values predicted by the Newtonian liquid model. The frequency band technique improved the magnitude results. The obtained viscosity values came close to those measured by the rotational viscometer with percentage errors up to 14%, whereas errors up to 96% were found for the single frequency method.

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This work presents the implementation of the ultrasonic shear reflectance method for viscosity measurement of Newtonian liquids using wave mode conversion from longitudinal to shear waves and vice versa. The method is based on the measurement of the complex reflection coefficient (magnitude and phase) at a solid-liquid interface. The implemented measurement cell is composed of an ultrasonic transducer, a water buffer, an aluminum prism, a PMMA buffer rod, and a sample chamber. Viscosity measurements were made in the range from 1 to 3.5 MHz for olive oil and for automotive oils (SAE 40, 90, and 250) at 15 and 22.5 degrees C, respectively. Moreover, olive oil and corn oil measurements were conducted in the range from 15 to 30 degrees C at 3.5 and 2.25 MHz, respectively. The ultrasonic measurements, in the case of the less viscous liquids, agree with the results provided by a rotational viscometer, showing Newtonian behavior. In the case of the more viscous liquids, a significant difference was obtained, showing a clear non-Newtonian behavior that cannot be described by the Kelvin-Voigt model.

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Objectives: The AMS 800TM is the current artificial urinary sphincter (AUS) for incontinence due to intrinsic sphincter deficiency. Despite good clinical results, technical failures inherent to the hydraulic mechanism or urethral ischemic injury contribute to revisions up to 60%. We are developing an electronic AUS, called ARTUS to overcome the rigors of AMS. The objective of this study was to evaluate the technical efficacy and tissue tolerance of the ARTUS system in an animal model.Methods: The ARTUS is composed by three parts: the contractile unit, a series of rings and an integrated microprocessor. The contractile unit is made of Nitinol fibers. The rings are placed around the urethra to control the flow of urine by squeezing the urethra. They work in a sequential alternative mode and are controlled by a microprocessor. In the first phase a three-rings device was used while in the second phase a two-rings ARTUS was used. The device was implanted in 14 sheep divided in two groups of six and eight animals for study purpose. The first group aimed at bladder leak point pressure (BLPP) measurement and validation of the animal model; the second group aimed at verifying mid-term tissue tolerance by explants at twelve weeks. General animal tolerance was also evaluated.Results: The ARTUS system implantation was uneventful. When the system was activated, the BLPP was measured at 1.038±0.044 bar (mean±SD). Urethral tissue analysis did not show significant morphological changes. No infection and no sign of discomfort were noted in animals at 12 weeks.Conclusions: The ARTUS proved to be effective in continence achievement in this study. Histological results support our idea that a sequential alternative mode can avoid urethral atrophy and ischemia. Further technical developments are needed to verify long-term outcome and permit human use.

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The advances of the semiconductor industry enable microelectromechanical systems sensors, signal conditioning logic and network access to be integrated into a smart sensor node. In this framework, a mixed-mode interface circuit for monolithically integrated gas sensor arrays was developed with high-level design techniques. This interface system includes analog electronics for inspection of up to four sensor arrays and digital logic for smart control and data communication. Although different design methodologies were used in the conception of the complete circuit, high-level synthesis tools and methodologies were crucial in speeding up the whole design cycle, enhancing reusability for future applications and producing a flexible and robust component.

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Objectives: The AMS 800 is the current artifi cial urinary sphincter (AUS) forincontinence due to intrinsic sphincter defi ciency. Despite good clinical results,technical failures inherent to the hydraulic mechanism or urethral ischemicinjury contribute to revisions up to 60%. We are developing an electronic AUS,called ARTUS to overcome the rigors of AMS. The objective of this study wasto evaluate the technical effi cacy and tissue tolerance of the ARTUS systemin an animal model.Methods: The ARTUS is composed by three parts: thecontractile unit, a series of rings and an integrated microprocessor. The contractileunit is made of Nitinol fi bers. The rings are placed around the urethrato control the fl ow of urine by squeezing the urethra. They work in a sequentialalternative mode and are controlled by a microprocessor. In the fi rst phase athree-rings device was used while in the second phase a two-rings ARTUS wasused. The device was implanted in 14 sheep divided in two groups of six andeight animals for study purpose. The fi rst group aimed at bladder leak pointpressure (BLPP) measurement and validation of the animal model; the secondgroup aimed at verifying midterm tissue tolerance by explants at twelve weeks.General animal tolerance was also evaluated.Results: The ARTUS systemimplantation was uneventful. When the system was activated, the BLPP wasmeasured at 1.038 ± 0.044 bar (mean ± SD). Urethral tissue analysis did notshow signifi cant morphological changes. No infection and no sign of discomfortwere noted in animals at 12 weeks.Conclusions: The ARTUS proved to beeffective in continence achievement in this study. Histological results supportour idea that a sequential alternative mode can avoid urethral atrophy andischemia. Further technical developments are needed to verify long-termoutcome and permit human use.

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Diplomityön tarkoituksena oli luoda ja kehittää kaksi asiakastyytyväisyysmallia asiakastyytyväisyyden mittaamisen aloittamiseksi ja toteuttamiseksi kohdeyrityksessä. Työ pohjautuu nykyisten tyytyväisyysprosessien analysointiin sekä työn teoriaosaan, joka käsittelee yksityiskohtaisesti niitä asioita, joita asiakastyytyväisyyden mittaamisessa ja prosessissa tulisi huomioida. Työssä tehdyn mallien tarkoituksen on auttaa kohdeyritystä hyödyntämään asiakastyytyväisyysmittauksen tuloksia paremmin liiketoiminnassa, sekä asiakkaiden keskuudessa. Työn yhtenä tavoitteena oli myös sopivan mittaustyökalun löytäminen ja suositteleminen kohdeyritykselle.Teorian ja analysoinnin pohjalta luotiin molemmat asiakastyytyväisyysmallit vastamaan kohdeyksiköiden tarpeita. Kun ulkoiset seikat, kuten mittaustavat, mittausinstrumentit, kyselylomakkeet ja vastaajaryhmät oli määritelty, keskityttiin tulosten analysointiin ja hyödyntämiseen, mikä korostui asiakassuuntautuneessa organisaatiossa. Työssä pohdittiin myös yhtenäisen asiakastyytyväisyysprosessin merkitystä ja etuja kohdeyrityksessä.

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Quality is not only free but it can be a profit maker. Every dollar that is not spent on doing things wrong becomes a dollar right on the bottom line. The main objective of this thesis is to give an answer on how cost of poor quality can be measured theoretically correctly. Different calculation methods for cost of poor quality are presented and discussed in order to give comprehensive picture about measurement process. The second objective is to utilize the knowledge from the literature review and to apply it when creating a method for measuring cost of poor quality in supplier performance rating. Literature review indicates that P-A-F model together with ABC methodology provides a mean for quality cost calculations. These models give an answer what should be measured and how this measurement should be carried out. However, when product or service quality costs are incurred when quality character derivates from target value, then QLF seems to be most appropriate methodology for quality cost calculation. These methodologies were applied when creating a quality cost calculation method for supplier performance ratings.

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Measurement is a tool for researching. Therefore, it is important that the measuring process is carried out correctly, without distorting the signal or the measured event. Researches of thermoelectric phenomena have been focused more on transverse thermoelectric phenomena during recent decades. Transverse Seebeck effect enables to produce thinner and faster heat flux sensor than before. Studies about transverse Seebeck effect have so far focused on materials, so in this Master’s Thesis instrumentation of transverse Seebeck effect based heat flux sensor is studied, This Master’s Thesis examines an equivalent circuit of transverse Seebeck effect heat flux sensors, their connectivity to electronics and choosing and design a right type amplifier. The research is carried out with a case study which is Gradient Heat Flux Sensors and an electrical motor. In this work, a general equivalent circuit was presented for the transverse Seebeck effect-based heat flux sensor. An amplifier was designed for the sensor of the case study, and the solution was produced for the measurement of the local heat flux of the electric motor to improve the electromagnetic compatibility.

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In recent years, technological advancements in microelectronics and sensor technologies have revolutionized the field of electrical engineering. New manufacturing techniques have enabled a higher level of integration that has combined sensors and electronics into compact and inexpensive systems. Previously, the challenge in measurements was to understand the operation of the electronics and sensors, but this has now changed. Nowadays, the challenge in measurement instrumentation lies in mastering the whole system, not just the electronics. To address this issue, this doctoral dissertation studies whether it would be beneficial to consider a measurement system as a whole from the physical phenomena to the digital recording device, where each piece of the measurement system affects the system performance, rather than as a system consisting of small independent parts such as a sensor or an amplifier that could be designed separately. The objective of this doctoral dissertation is to describe in depth the development of the measurement system taking into account the challenges caused by the electrical and mechanical requirements and the measurement environment. The work is done as an empirical case study in two example applications that are both intended for scientific studies. The cases are a light sensitive biological sensor used in imaging and a gas electron multiplier detector for particle physics. The study showed that in these two cases there were a number of different parts of the measurement system that interacted with each other. Without considering these interactions, the reliability of the measurement may be compromised, which may lead to wrong conclusions about the measurement. For this reason it is beneficial to conceptualize the measurement system as a whole from the physical phenomena to the digital recording device where each piece of the measurement system affects the system performance. The results work as examples of how a measurement system can be successfully constructed to support a study of sensors and electronics.