1,721,225 research outputs found
Additiivisin menetelmin valmistetun rakenteellisen hybridielektroniikan laadun arviointi ja luotettavuus
No full textAbstractThis thesis investigated the feasibility of hybrid and structural electronics as well as the applicability of simulation-assisted structural analysis as a technology development tool. Additionally, it analyzed the process throughput yield, product quality, and reliability. The topic is approached by studying the hybrid structural electronic samples and the influence of fabrication, and operational conditions on their performance.During the study, four different sample types and two simulation models were utilized. The feasibility of hybrid structural electronics was analyzed using the COMSOL Multiphysics simulation environment and non-destructive optical and electrical measurement methods. To evaluate the reliability in cyclic rotational bending, an in-house build testing system was used.The potential locations and reasons for structural failures were identified by a simulation-assisted structural analysis. As results, prominent parameters influencing the hybrid electronics structure (mechanical strength, thermal conductivity, etc.) were identified and design guidelines were suggested. Mechanical stresses during the fabrication and usage of a device (e.g., thermal expansion) can be minimized by utilizing the results of this analysis, thus having a positive influence on the reliability of the final product.The study proved that the concept of hybrid and structural electronics enables new properties for electronics (e.g., better thermal management or mechanical durability). A simulation-assisted, non-destructive structural analysis was also found to be a suitable characterization method for this kind of technology. According to the results, the process throughput yield, product quality and reliability can be enhanced with the proper design choices and manufacturing parameters.Original papersOriginal papers are not included in the electronic version of the dissertation.Lauri, J., Hannila, E., & Fabritius, T. (2019). Non-destructive characterization of glass laminated electronics. In 2019 IEEE International Instrumentation and Measurement Technology Conference (I2MTC), 1–5. https://doi.org/10.1109/I2MTC.2019.8827057Self-archived versionHannila, E., Augustine, B., Kurkela, T., Lauri, J., & Fabritius, T. (2019). Yield and electrical functionality of the glass-laminated conductive wires and connectors. IEEE Transactions on Components, Packaging and Manufacturing Technology, 9(12), 2499–2505. https://doi.org/10.1109/TCPMT.2019.2923858Self-archived versionHannila, E., Remes, K., Kurkela, T., Happonen, T., Keränen, K., & Fabritius, T. (2020). The effect of torsional bending on reliability and lifetime of printed silver conductors. IEEE Transactions on Electron Devices, 67(6), 2522–2528. https://doi.org/10.1109/TED.2020.2990125Self-archived versionHannila, E., Heinilehto, N., Lauri, J., Keränen, K., & Fabritius, T. (2020). Measuring and modelling the thermal behavior of LEDs in structural electronics. In 2020 IEEE International Instrumentation and Measurement Technology Conference (I2MTC), 1–6. https://doi.org/10.1109/I2MTC43012.2020.9128941Self-archived versionHannila, E., Heinilehto, N., Remes, K., Lauri, J., Keränen, K., & Fabritius, T. (2020). Hybrid thermal modeling to predict LED thermal behavior in hybrid electronics. IEEE Transactions on Instrumentation and Measurement, 70, 6001910. https://doi.org/10.1109/TIM.2020.3043112Self-archived versionTiivistelmäTässä opinnäytetyössä tutkittiin hybridielektroniikan ja rakenteellisen elektroniikan valmistettavuutta sekä simulaatioavusteisen rakenneanalyysin soveltuvuutta teknologiakehityksen työkaluna. Lisäksi opinnäytetyössä analysoitiin teknologian valmistusprosessin saantoa, tuotteiden laatua ja luotettavuutta. Aihetta lähestyttiin tutkimalla hybridielektroniikan näytteitä ja sekä valmistuksen että käytön aikaisten olosuhteiden vaikutusta niiden toimintaan.Tutkimuksen aikana hyödynnettiin neljää eri näytetyyppiä ja kahta simulaatiomallia. Hybridi- ja rakenteellisen elektroniikan toteutettavuutta analysoitiin hyödyntämällä COMSOL Multiphysics -simulaatioympäristöä sekä pintaa rikkomattomia, optisia ja sähköisiä mittausmenetelmiä. Luotettavuuden arvioimiseksi syklisessä kiertotaivutustestauksessa hyödynnettiin itse rakennettua mittausjärjestelmää.Simulaatioavusteisen rakenneanalyysin avulla rakenteesta tunnistettiin vioittumiselle potentiaalisia paikkoja. Analyysin pohjalta tunnistettiin myös keskeisiä suunnitteluehtoja ja -parametreja, joilla voidaan vaikuttaa rakenteen mekaaniseen lujuuteen tai lämmönjohtokykyyn. Rakenteen valmistuksessa ja käytön aikana syntyviä mekaanisia jännitteitä (lämpölaajeneminen yms.) voidaan minimoida hyödyntämällä analyysin tuloksia ja vaikuttaa positiivisesti myös lopullisen laitteen luotettavuuteen.Tutkimus osoitti, että hybridi- ja rakenteellisen elektroniikan konsepti mahdollistaa uusia ominaisuuksia elektroniikalle (mm. parempi lämmönhallinta tai mekaaninen kestävyys). Simulaatioavusteinen, pintaa rikkomaton rakenneanalyysi todettiin myös tälle teknologialle soveltuvaksi karakterisointimenetelmäksi. Tuloksien mukaan prosessin tuottoa, tuotteen laatua ja luotettavuutta voidaan parantaa oikeilla suunnitteluvalinnoilla ja valmistusparametreilla.OsajulkaisutOsajulkaisut eivät sisälly väitöskirjan elektroniseen versioon.Lauri, J., Hannila, E., & Fabritius, T. (2019). Non-destructive characterization of glass laminated electronics. In 2019 IEEE International Instrumentation and Measurement Technology Conference (I2MTC), 1–5. https://doi.org/10.1109/I2MTC.2019.8827057Rinnakkaistallennettu versioHannila, E., Augustine, B., Kurkela, T., Lauri, J., & Fabritius, T. (2019). Yield and electrical functionality of the glass-laminated conductive wires and connectors. IEEE Transactions on Components, Packaging and Manufacturing Technology, 9(12), 2499–2505. https://doi.org/10.1109/TCPMT.2019.2923858Rinnakkaistallennettu versioHannila, E., Remes, K., Kurkela, T., Happonen, T., Keränen, K., & Fabritius, T. (2020). The effect of torsional bending on reliability and lifetime of printed silver conductors. IEEE Transactions on Electron Devices, 67(6), 2522–2528. https://doi.org/10.1109/TED.2020.2990125Rinnakkaistallennettu versioHannila, E., Heinilehto, N., Lauri, J., Keränen, K., & Fabritius, T. (2020). Measuring and modelling the thermal behavior of LEDs in structural electronics. In 2020 IEEE International Instrumentation and Measurement Technology Conference (I2MTC), 1–6. https://doi.org/10.1109/I2MTC43012.2020.9128941Rinnakkaistallennettu versioHannila, E., Heinilehto, N., Remes, K., Lauri, J., Keränen, K., & Fabritius, T. (2020). Hybrid thermal modeling to predict LED thermal behavior in hybrid electronics. IEEE Transactions on Instrumentation and Measurement, 70, 6001910. https://doi.org/10.1109/TIM.2020.3043112Rinnakkaistallennettu versioAcademic dissertation to be presented with the assent of the Doctoral Programme Committee of Information Technology and Electrical Engineering of the University of Oulu for public defence in the Arina auditorium (TA105), Linnanmaa, on 16 June 2023, at 12 noonAbstract
This thesis investigated the feasibility of hybrid and structural electronics as well as the applicability of simulation-assisted structural analysis as a technology development tool. Additionally, it analyzed the process throughput yield, product quality, and reliability. The topic is approached by studying the hybrid structural electronic samples and the influence of fabrication, and operational conditions on their performance.
During the study, four different sample types and two simulation models were utilized. The feasibility of hybrid structural electronics was analyzed using the COMSOL Multiphysics simulation environment and non-destructive optical and electrical measurement methods. To evaluate the reliability in cyclic rotational bending, an in-house build testing system was used.
The potential locations and reasons for structural failures were identified by a simulation-assisted structural analysis. As results, prominent parameters influencing the hybrid electronics structure (mechanical strength, thermal conductivity, etc.) were identified and design guidelines were suggested. Mechanical stresses during the fabrication and usage of a device (e.g., thermal expansion) can be minimized by utilizing the results of this analysis, thus having a positive influence on the reliability of the final product.
The study proved that the concept of hybrid and structural electronics enables new properties for electronics (e.g., better thermal management or mechanical durability). A simulation-assisted, non-destructive structural analysis was also found to be a suitable characterization method for this kind of technology. According to the results, the process throughput yield, product quality and reliability can be enhanced with the proper design choices and manufacturing parameters.Tiivistelmä
Tässä opinnäytetyössä tutkittiin hybridielektroniikan ja rakenteellisen elektroniikan valmistettavuutta sekä simulaatioavusteisen rakenneanalyysin soveltuvuutta teknologiakehityksen työkaluna. Lisäksi opinnäytetyössä analysoitiin teknologian valmistusprosessin saantoa, tuotteiden laatua ja luotettavuutta. Aihetta lähestyttiin tutkimalla hybridielektroniikan näytteitä ja sekä valmistuksen että käytön aikaisten olosuhteiden vaikutusta niiden toimintaan.
Tutkimuksen aikana hyödynnettiin neljää eri näytetyyppiä ja kahta simulaatiomallia. Hybridi- ja rakenteellisen elektroniikan toteutettavuutta analysoitiin hyödyntämällä COMSOL Multiphysics -simulaatioympäristöä sekä pintaa rikkomattomia, optisia ja sähköisiä mittausmenetelmiä. Luotettavuuden arvioimiseksi syklisessä kiertotaivutustestauksessa hyödynnettiin itse rakennettua mittausjärjestelmää.
Simulaatioavusteisen rakenneanalyysin avulla rakenteesta tunnistettiin vioittumiselle potentiaalisia paikkoja. Analyysin pohjalta tunnistettiin myös keskeisiä suunnitteluehtoja ja -parametreja, joilla voidaan vaikuttaa rakenteen mekaaniseen lujuuteen tai lämmönjohtokykyyn. Rakenteen valmistuksessa ja käytön aikana syntyviä mekaanisia jännitteitä (lämpölaajeneminen yms.) voidaan minimoida hyödyntämällä analyysin tuloksia ja vaikuttaa positiivisesti myös lopullisen laitteen luotettavuuteen.
Tutkimus osoitti, että hybridi- ja rakenteellisen elektroniikan konsepti mahdollistaa uusia ominaisuuksia elektroniikalle (mm. parempi lämmönhallinta tai mekaaninen kestävyys). Simulaatioavusteinen, pintaa rikkomaton rakenneanalyysi todettiin myös tälle teknologialle soveltuvaksi karakterisointimenetelmäksi. Tuloksien mukaan prosessin tuottoa, tuotteen laatua ja luotettavuutta voidaan parantaa oikeilla suunnitteluvalinnoilla ja valmistusparametreilla
Painoteknisesti valmistettavat komponentit optiikan ja elektroniikan sovelluksiin
No full textAbstractThis thesis investigates how printing methods can be used to fabricate components for optics and electronics applications. Three different components were chosen, in order to demonstrate the technology’s versatility: a microlens array, a memristor and a double-sided capacitive sensor. While the work focused on design and fabrication aspects, the components’ functionality was also verified through appropriate methods.Polymer microlens arrays were fabricated by inkjet printing on both polyethylene terephthalate and glass substrates, and their physical characteristics were inspected. After additional investigation, the lens array fabricated on a glass substrate was determined to have imaging quality equal to the commercial glass reference, thus becoming a viable cost-effective alternative to an expensive glass lens array.The memristors were fabricated solely through inkjet printing. The fabricated structure had a TiOx layer printed between two silver electrodes. The physical and electrical properties of the fabricated samples were characterized. The memristivity of the component was proven functional, making the memristor one of the first fully inkjet printed ones.The third component was a screen-printed double-sided capacitive sensor. It was fabricated on an air filter to monitor the filter’s dirtiness level. One side of the sensor reacted to the particle accumulation, and the other side acted as a reference to provide better selectivity. By measuring the capacitance difference between the two sides, the dirtiness level could be determined case-by-case. The sensor concept was evaluated with a simple lint-placement test, and with a vacuum cleaner to achieve proper air flow through the filter. The experiments complemented each other, as an increase in the capacitance difference was observed in both tests.The obtained results and implemented components exemplify the great potential and variety of printed intelligence in many fields of research, and their eventual impact on our everyday life.Original papersOriginal papers are not included in the electronic version of the dissertation.Vilmi, P., Myllylä, R., & Fabritius, T. (2013). Inkjet printed microlens array on patterned substrate. In G. von Freymann, W. V. Schoenfeld, & R. C. Rumpf (Eds.), Advanced Fabrication Technologies for Micro/Nano Optics and Photonics VI. SPIE. https://doi.org/10.1117/12.2001045Vilmi, P., Varjo, S., Sliz, R., Hannuksela, J., & Fabritius, T. (2015). Disposable optics for microscopy diagnostics. Scientific Reports, 5(1). https://doi.org/10.1038/srep16957Vilmi, P., Nelo, M., Voutilainen, J.-V., Palosaari, J., Pörhönen, J., Tuukkanen, S., Jantunen, H., Juuti, J., & Fabritius, T. (2016). Fully printed memristors for a self-sustainable recorder of mechanical energy. Flexible and Printed Electronics, 1(2), 025002. https://doi.org/10.1088/2058-8585/1/2/025002Vilmi, P., Sliz, R., & Fabritius, T. (2020). Double-sided environmental sensor for high-efficiency particulate air filter. 2020 IEEE International Instrumentation and Measurement Technology Conference (I2MTC). https://doi.org/10.1109/i2mtc43012.2020.9128647Self-archived versionVilmi, P., Schuss, C., Hannila, E., Sliz, R., & Fabritius, T. (2021). Printed dust accumulation sensing system for air filters. Manuscript in preparation.TiivistelmäTässä väitöskirjassa tutkitaan, kuinka painomenetelmillä voidaan valmistaa komponentteja optiikan ja elektroniikan sovelluksiin. Tutkimukseen valittiin kolme erilaista komponenttia osoittamaan painomenetelmien monipuolisuutta: mikrolinssimatriisi, memristori ja kaksipuolinen kapasitiivinen anturi. Suunnittelu ja valmistus pidettiin työn painopisteenä, mutta myös komponenttien toimivuus varmistettiin asianmukaisin menetelmin.Polymeerimikrolinssit valmistettiin mustesuihkutulostuksella sekä polyetyleenitereftalaatti- että lasisubstraatille, ja niiden fyysisiä ominaisuuksia tutkittiin. Lasisubstraatille valmistetun linssimatriisin kuvantamisominaisuuksia tutkittaessa todettiin niiden olevan samantasoisia kuin kaupallisella lasilinssimatriisilla. Huomattavasti matalampien valmistuskustannuksien vuoksi polymeerilinssit ovat kustannustehokas vaihtoehto kalliille lasilinsseille.Memristorien valmistukseen käytettiin pelkästään mustesuihkutulostusta. Memristorin kerrosrakenteessa on kahden hopeakerroksen välissä ohut TiOx-kerros. Valmistettujen näytteiden fyysisiä ja sähköisiä ominaisuuksia tutkittiin. Komponentti todettiin memristiiviseksi, ja oli näin ollen yksi ensimmäisistä täysin mustesuihkutulostuksella valmistetuista.Kolmas komponentti oli silkkipainolla valmistettu kaksipuolinen kapasitiivinen anturi, joka painettiin ilmansuodattimen pintaan havainnoimaan suodattimen likaisuutta. Anturin toinen puoli reagoi hiukkasten kertymiseen suodattimen pintaan ja toinen puoli toimii referenssinä selektiivisyyden parantamiseksi. Mittaamalla kapasitanssiero puolien välillä, likaisuus voidaan määrittää tapauskohtaisesti. Konseptia testattiin yksinkertaisella nukkatestillä ja pölynimurilla, jolla saatiin ilmavirta suodattimen läpi. Testit täydensivät toisiaan, sillä kapasitanssieron kasvu havaittiin molemmissa testeissä.Työn tulokset ja toteutetut komponentit havainnollistavat painettavan älykkyyden loistavia mahdollisuuksia ja monipuolisuutta niin tieteen eri aloilla kuin ihmisten arkipäivän elämässä.OsajulkaisutOsajulkaisut eivät sisälly väitöskirjan elektroniseen versioon.Vilmi, P., Myllylä, R., & Fabritius, T. (2013). Inkjet printed microlens array on patterned substrate. In G. von Freymann, W. V. Schoenfeld, & R. C. Rumpf (Eds.), Advanced Fabrication Technologies for Micro/Nano Optics and Photonics VI. SPIE. https://doi.org/10.1117/12.2001045Vilmi, P., Varjo, S., Sliz, R., Hannuksela, J., & Fabritius, T. (2015). Disposable optics for microscopy diagnostics. Scientific Reports, 5(1). https://doi.org/10.1038/srep16957Vilmi, P., Nelo, M., Voutilainen, J.-V., Palosaari, J., Pörhönen, J., Tuukkanen, S., Jantunen, H., Juuti, J., & Fabritius, T. (2016). Fully printed memristors for a self-sustainable recorder of mechanical energy. Flexible and Printed Electronics, 1(2), 025002. https://doi.org/10.1088/2058-8585/1/2/025002Vilmi, P., Sliz, R., & Fabritius, T. (2020). Double-sided environmental sensor for high-efficiency particulate air filter. 2020 IEEE International Instrumentation and Measurement Technology Conference (I2MTC). https://doi.org/10.1109/i2mtc43012.2020.9128647Rinnakkaistallennettu versioVilmi, P., Schuss, C., Hannila, E., Sliz, R., & Fabritius, T. (2021). Printed dust accumulation sensing system for air filters. Manuscript in preparation.Academic dissertation to be presented with the assent of the Doctoral Training Committee of Information Technology and Electrical Engineering of the University of Oulu for public defence in Martti Ahtisaari -sali (L2), Linnanmaa, on 26 February 2021, at 12 noonAbstract
This thesis investigates how printing methods can be used to fabricate components for optics and electronics applications. Three different components were chosen, in order to demonstrate the technology’s versatility: a microlens array, a memristor and a double-sided capacitive sensor. While the work focused on design and fabrication aspects, the components’ functionality was also verified through appropriate methods.
Polymer microlens arrays were fabricated by inkjet printing on both polyethylene terephthalate and glass substrates, and their physical characteristics were inspected. After additional investigation, the lens array fabricated on a glass substrate was determined to have imaging quality equal to the commercial glass reference, thus becoming a viable cost-effective alternative to an expensive glass lens array.
The memristors were fabricated solely through inkjet printing. The fabricated structure had a TiOx layer printed between two silver electrodes. The physical and electrical properties of the fabricated samples were characterized. The memristivity of the component was proven functional, making the memristor one of the first fully inkjet printed ones.
The third component was a screen-printed double-sided capacitive sensor. It was fabricated on an air filter to monitor the filter’s dirtiness level. One side of the sensor reacted to the particle accumulation, and the other side acted as a reference to provide better selectivity. By measuring the capacitance difference between the two sides, the dirtiness level could be determined case-by-case. The sensor concept was evaluated with a simple lint-placement test, and with a vacuum cleaner to achieve proper air flow through the filter. The experiments complemented each other, as an increase in the capacitance difference was observed in both tests.
The obtained results and implemented components exemplify the great potential and variety of printed intelligence in many fields of research, and their eventual impact on our everyday life.Tiivistelmä
Tässä väitöskirjassa tutkitaan, kuinka painomenetelmillä voidaan valmistaa komponentteja optiikan ja elektroniikan sovelluksiin. Tutkimukseen valittiin kolme erilaista komponenttia osoittamaan painomenetelmien monipuolisuutta: mikrolinssimatriisi, memristori ja kaksipuolinen kapasitiivinen anturi. Suunnittelu ja valmistus pidettiin työn painopisteenä, mutta myös komponenttien toimivuus varmistettiin asianmukaisin menetelmin.
Polymeerimikrolinssit valmistettiin mustesuihkutulostuksella sekä polyetyleenitereftalaatti- että lasisubstraatille, ja niiden fyysisiä ominaisuuksia tutkittiin. Lasisubstraatille valmistetun linssimatriisin kuvantamisominaisuuksia tutkittaessa todettiin niiden olevan samantasoisia kuin kaupallisella lasilinssimatriisilla. Huomattavasti matalampien valmistuskustannuksien vuoksi polymeerilinssit ovat kustannustehokas vaihtoehto kalliille lasilinsseille.
Memristorien valmistukseen käytettiin pelkästään mustesuihkutulostusta. Memristorin kerrosrakenteessa on kahden hopeakerroksen välissä ohut TiOx-kerros. Valmistettujen näytteiden fyysisiä ja sähköisiä ominaisuuksia tutkittiin. Komponentti todettiin memristiiviseksi, ja oli näin ollen yksi ensimmäisistä täysin mustesuihkutulostuksella valmistetuista.
Kolmas komponentti oli silkkipainolla valmistettu kaksipuolinen kapasitiivinen anturi, joka painettiin ilmansuodattimen pintaan havainnoimaan suodattimen likaisuutta. Anturin toinen puoli reagoi hiukkasten kertymiseen suodattimen pintaan ja toinen puoli toimii referenssinä selektiivisyyden parantamiseksi. Mittaamalla kapasitanssiero puolien välillä, likaisuus voidaan määrittää tapauskohtaisesti. Konseptia testattiin yksinkertaisella nukkatestillä ja pölynimurilla, jolla saatiin ilmavirta suodattimen läpi. Testit täydensivät toisiaan, sillä kapasitanssieron kasvu havaittiin molemmissa testeissä.
Työn tulokset ja toteutetut komponentit havainnollistavat painettavan älykkyyden loistavia mahdollisuuksia ja monipuolisuutta niin tieteen eri aloilla kuin ihmisten arkipäivän elämässä
Electric arc characterisation and furnace process monitoring with optical emission spectroscopy and image analysis
No full textAbstractElectric arc furnaces (EAFs) and ladle furnaces (LFs) are the main recycling units for scrap metal. With lower CO₂ emissions than traditional ore-based steelmaking, the importance of EAFs can be expected to increase in the future. Increasing steel production rates and demand for high-quality and special steels require innovative process control systems to be developed for the steel industry. However, the harsh conditions inside the furnaces set strict requirements for durability and viable data acquisition methods for online measurement systems.In this thesis, the applicability of optical emission spectroscopy (OES) as an online measurement system for industrial EAFs and LFs is discussed, based on the results from pilot-scale and industrial EAFs, and an industrial LF.The electric arc has been characterised with OES, plasma diagnostics, and image analysis in the pilot-scale EAF measurements. These studies highlighted the influence of slag composition on the overall properties of the electric arc, the electrical parameters of the furnace, and the arc length{voltage relation. The majority of the atomic emission lines in the electric arc OES spectra were observed to originate from the slag components.In the industrial EAF campaign, high alloyed steel grade was observed to have high-quality arc spectra within 30 mins before tapping and higher radiative heat transfer compared with the carbon steel grade. The spectra from the carbon steel grade, on the other hand, were used to observe how spectra evolve during slag foaming. Additionally, the molten bath surface temperature was estimated from the OES spectra. The slag composition was evaluated with OES in the industrial LF campaign, indicating that the CaF₂, MgO, and MnO content of the slag could be evaluated from the spectra.Original papersOriginal papers are not included in the electronic version of the dissertation.Pauna, H., Willms, T., Aula, M., Echterhof, T., Huttula, M., & Fabritius, T. (2019). Pilot-scale AC electric arc furnace plasma characterization. Plasma Research Express, 1(3), 035007. https://doi.org/10.1088/2516-1067/ab30ddSelf-archived versionPauna, H., Willms, T., Aula, M., Echterhof, T., Huttula, M., & Fabritius, T. (2020). Electric Arc Length-Voltage and Conductivity Characteristics in a Pilot-Scale AC Electric Arc Furnace. Metallurgical and Materials Transactions B, 51(4), 1646–1655. https://doi.org/10.1007/s11663-020-01859-zSelf-archived versionPauna, H., Aula, M., Seehausen, J., Klung, J.-S., Huttula, M., & Fabritius, T. (2020). Optical Emission Spectroscopy as an Online Analysis Method in Industrial Electric Arc Furnaces. Steel Research International, 2000051. https://doi.org/10.1002/srin.202000051Self-archived versionPauna, H., Aula, M., Seehausen, J., Klung, J.-S., Huttula, M., & Fabritius, T. (2020). Industrial Ladle Furnace Slag Composition Analysis with Optical Emissions from the Arc. ISIJ International, 60(9), 1985–1992. https://doi.org/10.2355/isijinternational.isijint-2019-676Self-archived versionOsajulkaisutOsajulkaisut eivät sisälly väitöskirjan elektroniseen versioon.Pauna, H., Willms, T., Aula, M., Echterhof, T., Huttula, M., & Fabritius, T. (2019). Pilot-scale AC electric arc furnace plasma characterization. Plasma Research Express, 1(3), 035007. https://doi.org/10.1088/2516-1067/ab30ddRinnakkaistallennettu versioPauna, H., Willms, T., Aula, M., Echterhof, T., Huttula, M., & Fabritius, T. (2020). Electric Arc Length-Voltage and Conductivity Characteristics in a Pilot-Scale AC Electric Arc Furnace. Metallurgical and Materials Transactions B, 51(4), 1646–1655. https://doi.org/10.1007/s11663-020-01859-zRinnakkaistallennettu versioPauna, H., Aula, M., Seehausen, J., Klung, J.-S., Huttula, M., & Fabritius, T. (2020). Optical Emission Spectroscopy as an Online Analysis Method in Industrial Electric Arc Furnaces. Steel Research International, 2000051. https://doi.org/10.1002/srin.202000051Rinnakkaistallennettu versioPauna, H., Aula, M., Seehausen, J., Klung, J.-S., Huttula, M., & Fabritius, T. (2020). Industrial Ladle Furnace Slag Composition Analysis with Optical Emissions from the Arc. ISIJ International, 60(9), 1985–1992. https://doi.org/10.2355/isijinternational.isijint-2019-676Rinnakkaistallennettu versioAcademic dissertation to be presented with the assent of the Doctoral Training Committee of Technology and Natural Sciences of the University of Oulu for public discussion in the Auditorium L5, on October 30th, 2020, at 12 o'clock noon.Abstract
Electric arc furnaces (EAFs) and ladle furnaces (LFs) are the main recycling units for scrap metal. With lower CO₂ emissions than traditional ore-based steelmaking, the importance of EAFs can be expected to increase in the future. Increasing steel production rates and demand for high-quality and special steels require innovative process control systems to be developed for the steel industry. However, the harsh conditions inside the furnaces set strict requirements for durability and viable data acquisition methods for online measurement systems.
In this thesis, the applicability of optical emission spectroscopy (OES) as an online measurement system for industrial EAFs and LFs is discussed, based on the results from pilot-scale and industrial EAFs, and an industrial LF.
The electric arc has been characterised with OES, plasma diagnostics, and image analysis in the pilot-scale EAF measurements. These studies highlighted the influence of slag composition on the overall properties of the electric arc, the electrical parameters of the furnace, and the arc length{voltage relation. The majority of the atomic emission lines in the electric arc OES spectra were observed to originate from the slag components.
In the industrial EAF campaign, high alloyed steel grade was observed to have high-quality arc spectra within 30 mins before tapping and higher radiative heat transfer compared with the carbon steel grade. The spectra from the carbon steel grade, on the other hand, were used to observe how spectra evolve during slag foaming. Additionally, the molten bath surface temperature was estimated from the OES spectra. The slag composition was evaluated with OES in the industrial LF campaign, indicating that the CaF₂, MgO, and MnO content of the slag could be evaluated from the spectra
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Theoretical and numerical studies of dynamically tunable terahertz graphene-based chiral and anisotropic metamaterials
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This thesis investigates how theoretical and numerical approaches can be used to design and analyse tunable terahertz graphene-based chiral and anisotropic metamaterials for applications in optoelectronics. Nine variations of metamaterials were designed and analysed to demonstrate the versatility of the technique: single-, dual-, and multi-function metamaterials working as a filter, multiband absorbers, broadband and multiband mirror, switch, inverter, a refractive index sensor, and a biosensor. Metamaterials were designed and optimized numerically in Computer Simulation Technology (CST) Software, while Equivalent circuit models (ECMs), parameter retrieval method, and Kramers–Kronig relations-based MATLAB codes were utilized in theoretical analysis.
The proposed metamaterial designs are dynamically tunable by varying bias voltage and they showed impressive component level performance in the THz frequency range (0.3–5.5 THz). The best designed metamaterials exhibit a maximum linear dichroism (LD) response of 100%, maximum absorption of 100%, with maximum four absorption/reflection bands, a maximum switching extinction ratio of 33.01 dB and a maximum circular dichroism (CD) response of 20%. From a sensing performance point of view, the maximum refractive index sensitivity was 0.96 THz/refractive index unit. With certain designs, the number and location of the absorption and reflection bands can be adjusted by rotating the incident electromagnetic field.
The obtained results demonstrated the significant potential of metamaterials in various research fields, their potential impact on the optoelectronics industry and the possibility of a proper design to make graphene-based THz metastructure fabrication more feasible. Original papers Asgari, S., & Fabritius, T. (2020). Equivalent circuit model of graphene chiral multi-band metadevice absorber composed of U-shaped resonator array. Optics Express, 28(26), 39850. https://doi.org/10.1364/OE.412107 https://doi.org/10.1364/OE.412107 Self-archived version Asgari, S., & Fabritius, T. (2023). Terahertz graphene-based multi-functional anisotropic metamaterial and its equivalent circuit model. Scientific Reports, 13(1), 3433. https://doi.org/10.1038/s41598-023-30605-z https://doi.org/10.1038/s41598-023-30605-z Self-archived version Asgari, S., & Fabritius, T. (2021). Graphene-based dual-functional chiral metamirror composed of complementary 90° rotated U-shaped resonator arrays and its equivalent circuit model. Scientific Reports, 11(1), 23827. https://doi.org/10.1038/s41598-021-03457-8 https://doi.org/10.1038/s41598-021-03457-8 Self-archived version Asgari, S., & Fabritius, T. (2022). Graphene-based multiband chiral metamaterial absorbers comprised of square split-ring resonator arrays with different numbers of gaps, and their equivalent circuit model. IEEE Access, 10, 63658–63671. https://doi.org/10.1109/ACCESS.2022.3183272 https://doi.org/10.1109/ACCESS.2022.3183272 Self-archived version Asgari, S., & Fabritius, T. (2023). Numerical simulation and equivalent circuit model of multi-band terahertz absorber composed of double-sided graphene comb resonator array. IEEE Access, 11, 36052–36063. https://doi.org/10.1109/ACCESS.2023.3265804 https://doi.org/10.1109/ACCESS.2023.3265804 Self-archived version Asgari, S., Granpayeh, N., & Fabritius, T. (2020). Controllable terahertz cross-shaped three-dimensional graphene intrinsically chiral metastructure and its biosensing application. Optics Communications, 474, 126080. https://doi.org/10.1016/j.optcom.2020.126080 https://doi.org/10.1016/j.optcom.2020.126080 Self-archived version Tiivistelmä
Tässä opinnäytetyössä tutkitaan, kuinka teoreettisia ja numeerisia lähestymistapoja voidaan käyttää virittävien terahertsigrafeenipohjaisten kiraalisten ja anisotrooppisten metamateriaalien suunnittelussa ja analysoinnissa optoelektroniikan sovelluksiin. Metamateriaalien yhdeksän muunnelmaa suunniteltiin ja analysoitiin osoittamaan tekniikan monipuolisuutta: yksi-, kaksi- ja monitoimimetamateriaalit, jotka toimivat suodattimena, monikaistaiset vaimentimet, laajakaista- ja monikaistapeilit, kytkin, invertteri, taitekerroinanturi ja biosensori. Metamateriaalit suunniteltiin ja optimoitiin numeerisesti Computer Simulation Technology (CST) -ohjelmistossa. Teoreettisessa analyysissä hyödynnettiin ekvivalentteja piirimalleja (ECM), parametrien hakumenetelmää ja Kramers–Kronig-relaatioihin perustuvia MATLAB-koodeja.
Ehdotetut metamateriaalimallit ovat dynaamisesti viritettävissä vaihtelemalla esijännitettä ja ne osoittivat vaikuttavaa komponenttitason suorituskykyä THz-taajuusalueella (0,3–5,5 THz). Parhaiten suunniteltujen metamateriaalien lineaarinen dikroismi (LD) maksimivaste on 100 %, maksimiabsorptio 100 %, enintään neljä absorptio/heijastuskaistaa, suurin kytkentäsammutussuhde 33,01 dB ja maksimi pyöreä dikroismi (CD) vaste 20 %. Tunnistuksen suorituskyvyn kannalta suurin taitekerroinherkkyys oli 0,96 THz/taitekerroinyksikkö. Tietyissä malleissa absorptio- ja heijastuskaistojen lukumäärää ja sijaintia voidaan säätää kiertämällä tulevaa sähkömagneettista kenttää.
Saadut tulokset osoittivat metamateriaalien merkittävän potentiaalin eri tutkimusaloilla, niiden mahdollisen vaikutuksen optoelektroniikan teollisuuteen sekä mahdollisuuden oikeanlaiseen suunnitteluun grafeenipohjaisen THz-metarakenteen valmistuksen mahdollistamiseksi. Osajulkaisut Asgari, S., & Fabritius, T. (2020). Equivalent circuit model of graphene chiral multi-band metadevice absorber composed of U-shaped resonator array. Optics Express, 28(26), 39850. https://doi.org/10.1364/OE.412107 https://doi.org/10.1364/OE.412107 Rinnakkaistallennettu versio Asgari, S., & Fabritius, T. (2023). Terahertz graphene-based multi-functional anisotropic metamaterial and its equivalent circuit model. Scientific Reports, 13(1), 3433. https://doi.org/10.1038/s41598-023-30605-z https://doi.org/10.1038/s41598-023-30605-z Rinnakkaistallennettu versio Asgari, S., & Fabritius, T. (2021). Graphene-based dual-functional chiral metamirror composed of complementary 90° rotated U-shaped resonator arrays and its equivalent circuit model. Scientific Reports, 11(1), 23827. https://doi.org/10.1038/s41598-021-03457-8 https://doi.org/10.1038/s41598-021-03457-8 Rinnakkaistallennettu versio Asgari, S., & Fabritius, T. (2022). Graphene-based multiband chiral metamaterial absorbers comprised of square split-ring resonator arrays with different numbers of gaps, and their equivalent circuit model. IEEE Access, 10, 63658–63671. https://doi.org/10.1109/ACCESS.2022.3183272 https://doi.org/10.1109/ACCESS.2022.3183272 Rinnakkaistallennettu versio Asgari, S., & Fabritius, T. (2023). Numerical simulation and equivalent circuit model of multi-band terahertz absorber composed of double-sided graphene comb resonator array. IEEE Access, 11, 36052–36063. https://doi.org/10.1109/ACCESS.2023.3265804 https://doi.org/10.1109/ACCESS.2023.3265804 Rinnakkaistallennettu versio Asgari, S., Granpayeh, N., & Fabritius, T. (2020). Controllable terahertz cross-shaped three-dimensional graphene intrinsically chiral metastructure and its biosensing application. Optics Communications, 474, 126080. https://doi.org/10.1016/j.optcom.2020.126080 https://doi.org/10.1016/j.optcom.2020.126080 Rinnakkaistallennettu versio Academic dissertation to be presented with the assent of the Doctoral Programme Committee of Information Technology and Electrical Engineering of the University of Oulu for public defence in the OP auditorium (L10), Linnanmaa, on 7 June 2024, at 12 noonAbstract
This thesis investigates how theoretical and numerical approaches can be used to design and analyse tunable terahertz graphene-based chiral and anisotropic metamaterials for applications in optoelectronics. Nine variations of metamaterials were designed and analysed to demonstrate the versatility of the technique: single-, dual-, and multi-function metamaterials working as a filter, multiband absorbers, broadband and multiband mirror, switch, inverter, a refractive index sensor, and a biosensor. Metamaterials were designed and optimized numerically in Computer Simulation Technology (CST) Software, while Equivalent circuit models (ECMs), parameter retrieval method, and Kramers–Kronig relations-based MATLAB codes were utilized in theoretical analysis.
The proposed metamaterial designs are dynamically tunable by varying bias voltage and they showed impressive component level performance in the THz frequency range (0.3–5.5 THz). The best designed metamaterials exhibit a maximum linear dichroism (LD) response of 100%, maximum absorption of 100%, with maximum four absorption/reflection bands, a maximum switching extinction ratio of 33.01 dB and a maximum circular dichroism (CD) response of 20%. From a sensing performance point of view, the maximum refractive index sensitivity was 0.96 THz/refractive index unit. With certain designs, the number and location of the absorption and reflection bands can be adjusted by rotating the incident electromagnetic field.
The obtained results demonstrated the significant potential of metamaterials in various research fields, their potential impact on the optoelectronics industry and the possibility of a proper design to make graphene-based THz metastructure fabrication more feasible.Tiivistelmä
Tässä opinnäytetyössä tutkitaan, kuinka teoreettisia ja numeerisia lähestymistapoja voidaan käyttää virittävien terahertsigrafeenipohjaisten kiraalisten ja anisotrooppisten metamateriaalien suunnittelussa ja analysoinnissa optoelektroniikan sovelluksiin. Metamateriaalien yhdeksän muunnelmaa suunniteltiin ja analysoitiin osoittamaan tekniikan monipuolisuutta: yksi-, kaksi- ja monitoimimetamateriaalit, jotka toimivat suodattimena, monikaistaiset vaimentimet, laajakaista- ja monikaistapeilit, kytkin, invertteri, taitekerroinanturi ja biosensori. Metamateriaalit suunniteltiin ja optimoitiin numeerisesti Computer Simulation Technology (CST) -ohjelmistossa. Teoreettisessa analyysissä hyödynnettiin ekvivalentteja piirimalleja (ECM), parametrien hakumenetelmää ja Kramers–Kronig-relaatioihin perustuvia MATLAB-koodeja.
Ehdotetut metamateriaalimallit ovat dynaamisesti viritettävissä vaihtelemalla esijännitettä ja ne osoittivat vaikuttavaa komponenttitason suorituskykyä THz-taajuusalueella (0,3–5,5 THz). Parhaiten suunniteltujen metamateriaalien lineaarinen dikroismi (LD) maksimivaste on 100 %, maksimiabsorptio 100 %, enintään neljä absorptio/heijastuskaistaa, suurin kytkentäsammutussuhde 33,01 dB ja maksimi pyöreä dikroismi (CD) vaste 20 %. Tunnistuksen suorituskyvyn kannalta suurin taitekerroinherkkyys oli 0,96 THz/taitekerroinyksikkö. Tietyissä malleissa absorptio- ja heijastuskaistojen lukumäärää ja sijaintia voidaan säätää kiertämällä tulevaa sähkömagneettista kenttää.
Saadut tulokset osoittivat metamateriaalien merkittävän potentiaalin eri tutkimusaloilla, niiden mahdollisen vaikutuksen optoelektroniikan teollisuuteen sekä mahdollisuuden oikeanlaiseen suunnitteluun grafeenipohjaisen THz-metarakenteen valmistuksen mahdollistamiseksi
Avoimen silmäkkeen muodostumisen mallintaminen kaasuhuuhdellussa senkassa
No full textAbstractIn ladle metallurgy, gas stirring and the behaviour of the slag layer are very important for alloying and the homogenization of the steel. When gas is injected through a nozzle located at the bottom of the ladle into the metal bath, the gas jet exiting the nozzle breaks up into gas bubbles. The rising bubbles break the slag layer and create an open-eye. The size of the open-eye is very important as the efficiency of the metal-slag reactions depend on the interaction between the slag and steel created during the stirring process, and information about the position and size of the open-eye is important for effective alloying practice. Moreover, the open-eye has an effect on the energy balance since it increases heat losses.In this study, experimental measurements and numerical simulations were performed to study the effect of different operating parameters on the formation of the open-eye and mixing time in a water model and industrial ladle. Experimental measurements were performed to study the effect of the gas flow rate, slag layer thickness, slag layer densities and number of porous plugs in a 1/5 scale water model and in a 150-ton steelmaking ladle. For numerical modelling, a multi-phase volume of fluid (VOF) model was used to simulate the system including the behaviour of the slag layer. The numerical simulation of the open-eye size and mixing time was found to be in good agreement with the experimental data obtained from the water model and data obtained from the industrial measurements.Original papersOriginal papers are not included in the electronic version of the dissertation.Ramasetti, E.K., Visuri, V.-V., Sulasalmi, P., Kärnä, A., & Fabritius, T. (2017). Numerical study of multiphase flows in a ladle for different closure models. Proceedings of the 11th Pacific Symposium on Flow Visualization and Image Processing, Kumamoto University, Kumamoto, Japan.Self-archived versionRamasetti, E.K., Visuri, V.-V., Sulasalmi, P., & Fabritius, T. (2018). A CFD and experimental investigation of slag eye in gas stirred ladle. Journal of Fluid Flow, Heat and Mass Transfer, 5, 78-86. 10.11159/jffhmt.2018.008Self-archived versionRamasetti, E.K., Visuri, V.-V., Sulasalmi, P., Mattila, R., & Fabritius, T. (2019). Modeling of the effect of the gas flow rate on the fluid flow and open-eye formation in a water model of a steelmaking ladle. Steel Research International, 90(2), 1-15. https://doi.org/10.1002/srin.201800365Self-archived versionRamasetti, E.K., Visuri, V.-V., Sulasalmi, P., Gupta, A.K., Palovaara, T., & Fabritius, T. (2019). Physical and CFD modelling of the effect of top layer properties on the formation of open-eye in gas-stirred ladles with single and dual-plugs. Steel Research International, 1900088, 1-13. https://doi.org/10.1002/srin.201900088Self-archived versionRamasetti, E.K., Visuri, V.-V., Sulasalmi, P., Savolainen, J., Li, M., Shao, L., & Fabritius, T. (2019). Numerical modelling of the influence of argon flow rate and slag layer height on open-eye formation in a 150-ton steelmaking ladle. Metals, 9(10), 1048. https://doi.org/10.3390/met9101048Self-archived versionRamasetti, E.K., Visuri, V.-V., Sulasalmi, P., Fabritius, T., Saatio, T., Li, M., & Shao, L. (2019). Numerical modeling of open-eye formation and mixing time in argon stirred industrial ladle. Metals, 9(8), 829. https://doi.org/10.3390/met9080829Self-archived versionTiivistelmäSenkkametallurgiassa kaasuhuuhtelu ja kuonakerroksen käyttäytyminen ovat tärkeitä teräksen seostamisen ja homogenisoinnin näkökulmasta. Senkan pohjalla sijaitsevasta suuttimesta puhallettava kaasu hajoaa kupliksi, jotka rikkovat kuonakerroksen ja muodostavat avoimen silmäkkeen. Avoimen silmäkkeen koko on yhteydessä voimakkaampaan kuonan emulgoitumiseen, joka tehostaa metallisulan ja kuonan välisiä reaktioita. Tietoa avoimen silmäkkeen paikasta ja koosta tarvitaan myös tehokkaaseen seostuspraktiikkaan. Avoin silmäke vaikuttaa lisäksi prosessin energiataseeseen lisäten sen lämpöhäviöitä.Tässä tutkimuksessa tutkittiin kokeellisesti ja laskennallisesti erilaisten operointiparametrien vaikutusta avoimen silmäkkeen muodostumiseen vesimallissa ja terässenkassateollisessa senkassa. Kokeellisia mittauksia tehtiin kaasuhuuhtelun, kuonakerroksen paksuuden, ja suuttimien määrän vaikutuksen tutkimiseksi 1/5-mittakaavan vesimallissa ja 150 tonnin terässenkassa. Numeerisessa mallinnuksessa systeemin ja siihen lukeutuvan kuonakerroksen käyttäytymisen simuloimiseen käytettiin volume of fluid (VOF) -monifaasimenetelmää. Avoimen silmäkkeen kokoon ja sekoittumisaikaan liittyvien numeeristen simulointien havaittiin vastaavan hyvin vesimallista ja teollisista mittauksista saatua kokeellista aineistoa.OsajulkaisutOsajulkaisut eivät sisälly väitöskirjan elektroniseen versioon.Ramasetti, E.K., Visuri, V.-V., Sulasalmi, P., Kärnä, A., & Fabritius, T. (2017). Numerical study of multiphase flows in a ladle for different closure models. Proceedings of the 11th Pacific Symposium on Flow Visualization and Image Processing, Kumamoto University, Kumamoto, Japan.Rinnakkaistallennettu versioRamasetti, E.K., Visuri, V.-V., Sulasalmi, P., & Fabritius, T. (2018). A CFD and experimental investigation of slag eye in gas stirred ladle. Journal of Fluid Flow, Heat and Mass Transfer, 5, 78-86. 10.11159/jffhmt.2018.008Rinnakkaistallennettu versioRamasetti, E.K., Visuri, V.-V., Sulasalmi, P., Mattila, R., & Fabritius, T. (2019). Modeling of the effect of the gas flow rate on the fluid flow and open-eye formation in a water model of a steelmaking ladle. Steel Research International, 90(2), 1-15. https://doi.org/10.1002/srin.201800365Rinnakkaistallennettu versioRamasetti, E.K., Visuri, V.-V., Sulasalmi, P., Gupta, A.K., Palovaara, T., & Fabritius, T. (2019). Physical and CFD modelling of the effect of top layer properties on the formation of open-eye in gas-stirred ladles with single and dual-plugs. Steel Research International, 1900088, 1-13. https://doi.org/10.1002/srin.201900088Rinnakkaistallennettu versioRamasetti, E.K., Visuri, V.-V., Sulasalmi, P., Savolainen, J., Li, M., Shao, L., & Fabritius, T. (2019). Numerical modelling of the influence of argon flow rate and slag layer height on open-eye formation in a 150-ton steelmaking ladle. Metals, 9(10), 1048. https://doi.org/10.3390/met9101048Rinnakkaistallennettu versioRamasetti, E.K., Visuri, V.-V., Sulasalmi, P., Fabritius, T., Saatio, T., Li, M., & Shao, L. (2019). Numerical modeling of open-eye formation and mixing time in argon stirred industrial ladle. Metals, 9(8), 829. https://doi.org/10.3390/met9080829Rinnakkaistallennettu versioAcademic dissertation to be presented, with the assent of the Doctoral Training Committee of Technology and Natural Sciences of the University of Oulu, for public defence in the Arina auditorium (TA105), Linnanmaa, on 25 October 2019, at 12 noonAbstract
In ladle metallurgy, gas stirring and the behaviour of the slag layer are very important for alloying and the homogenization of the steel. When gas is injected through a nozzle located at the bottom of the ladle into the metal bath, the gas jet exiting the nozzle breaks up into gas bubbles. The rising bubbles break the slag layer and create an open-eye. The size of the open-eye is very important as the efficiency of the metal-slag reactions depend on the interaction between the slag and steel created during the stirring process, and information about the position and size of the open-eye is important for effective alloying practice. Moreover, the open-eye has an effect on the energy balance since it increases heat losses.
In this study, experimental measurements and numerical simulations were performed to study the effect of different operating parameters on the formation of the open-eye and mixing time in a water model and industrial ladle. Experimental measurements were performed to study the effect of the gas flow rate, slag layer thickness, slag layer densities and number of porous plugs in a 1/5 scale water model and in a 150-ton steelmaking ladle. For numerical modelling, a multi-phase volume of fluid (VOF) model was used to simulate the system including the behaviour of the slag layer. The numerical simulation of the open-eye size and mixing time was found to be in good agreement with the experimental data obtained from the water model and data obtained from the industrial measurements.Tiivistelmä
Senkkametallurgiassa kaasuhuuhtelu ja kuonakerroksen käyttäytyminen ovat tärkeitä teräksen seostamisen ja homogenisoinnin näkökulmasta. Senkan pohjalla sijaitsevasta suuttimesta puhallettava kaasu hajoaa kupliksi, jotka rikkovat kuonakerroksen ja muodostavat avoimen silmäkkeen. Avoimen silmäkkeen koko on yhteydessä voimakkaampaan kuonan emulgoitumiseen, joka tehostaa metallisulan ja kuonan välisiä reaktioita. Tietoa avoimen silmäkkeen paikasta ja koosta tarvitaan myös tehokkaaseen seostuspraktiikkaan. Avoin silmäke vaikuttaa lisäksi prosessin energiataseeseen lisäten sen lämpöhäviöitä.
Tässä tutkimuksessa tutkittiin kokeellisesti ja laskennallisesti erilaisten operointiparametrien vaikutusta avoimen silmäkkeen muodostumiseen vesimallissa ja terässenkassateollisessa senkassa. Kokeellisia mittauksia tehtiin kaasuhuuhtelun, kuonakerroksen paksuuden, ja suuttimien määrän vaikutuksen tutkimiseksi 1/5-mittakaavan vesimallissa ja 150 tonnin terässenkassa. Numeerisessa mallinnuksessa systeemin ja siihen lukeutuvan kuonakerroksen käyttäytymisen simuloimiseen käytettiin volume of fluid (VOF) -monifaasimenetelmää. Avoimen silmäkkeen kokoon ja sekoittumisaikaan liittyvien numeeristen simulointien havaittiin vastaavan hyvin vesimallista ja teollisista mittauksista saatua kokeellista aineistoa
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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