11 resultados para native sulfur

em Doria (National Library of Finland DSpace Services) - National Library of Finland, Finland


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Selostus: Viljellyn pensasmustikan ja luonnonvaraisten mustikan ja juolukan sienijuuret

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Zinc selenide is a prospective material for optoelectronics. The fabrication of ZnSe­based light-emitting diodes is hindered by complexity of p-type doping of the component materials. The interaction between native and impurity defects, the tendency of doping impurity to form associative centres with native defects and the tendency to self-compensation are the main factors impeding effective control of the value and type of conductivity. The thesis is devoted to the study of the processes of interaction between native and impurity defects in zinc selenide. It is established that the Au impurity has the most prominent amphoteric properties in ZnSe among Cu, Ag and Au impurities, as it forms a great number of both Au; donors and Auz„ acceptors. Electrical measurements show that Ag and Au ions introduced into vacant sites of the Zn sublattice form simple single-charged Agz„+ and Auzn+ states with d1° electron configuration, while Cu ions can form both single-charged Cuz„ (d1) and double-charged Cuzr`+ (d`o) centres. Amphoteric properties of Ag and Au transition metals stimulated by time are found for the first time from both electrical and luminescent measurements. A model that explains the changes in electrical and luminescent parameters by displacement of Ag ions into interstitial sites due to lattice deformation forces is proposed. Formation of an Ag;-donor impurity band in ZnSe samples doped with Ag and stored at room temperature is also studied. Thus, the properties of the doped samples are modified due to large lattice relaxation during aging. This fact should be taken into account in optoelectronic applications of doped ZnSe and related compounds.

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Användning av biomassa som energikälla för produktion av el och värme är ett sätt att minska beroendet av fossila bränslen och höja självförsörjningen av energi. Fossila bränslen är den främsta källan till koldioxid utsläpp förorsakad av människan. Biomassa, å andra sidan, betraktas som en koldioxidneutral energikälla. Svavlet och kvävet i biomassan bildar dock föroreningar såsom kväveoxider (NOX) och svaveldioxid (SO2), som bidrar till försurning av mark och sjöar. Svavlet i bränslet kan även både förorsaka och förhindra korrosion i en förbränningsanläggning, beroende på förbränningen och bränslet. Huvudsyftet med detta arbete var att få en bättre förståelse om hur utsläppen av NOX och SO2 bildas från bränslebundet kväve och svavel vid förbränning av olika biobränslen. Mätkampanjer i fullskaliga förbränningsanläggningar utfördes, där gassammansättningen mättes i eldstaden och rökgasen. Förståelsen om gaskemin i eldstaden är viktig, för att möjliggöra utvecklandet av renare och effektivare förbränningsanläggningar. Ett annat syfte med arbetet var att klargöra om sulfatering av askkomponenter vid förbränning av biobränslen med olika askegenskaper. Alkaliklorider som bildas vid biomassaförbränning kan orsaka korrosion av värmeöverföringsytor. Svavlet i bränslet visade sig ha en viktig roll i att sulfatera alkaliklorider till mindre korrosiva alkalisulfater. Närvaron av gasformig svavelsyra i rökgaskanalen av förbränningsanläggningar studerades även. Kondensering av svavelsyra leder till korrosion av rökgaskanalen och dess delar. Om svavelsyrakoncentrationen i rökgasen är känd, kan daggpunktstemperaturen beräknas och kondensering av svavelsyra förhindras. I arbetet utvecklades en mätmetod för att mäta låga koncentrationer av gasformig svavelsyra i rökgaser. Denna metod användes för att undersöka risken av lågtemperaturkorrosion orsakad av svavelsyra i förbränningsanläggningar. ------------------------------------------------------------------------------------------------------------ Käyttämällä biomassaa energianlähteenä voidaan vähentää sähkön- ja lämmöntuotannon riippuvuutta fossiilisiin polttoaineisiin. Biomassan käytöllä voidaan myös lisätä energiantuotannon omavaraisuutta. Fossiiliset polttoaineet ovat pääasiallinen syy ihmisen aiheuttamiin hiilidioksidipäästöihin. Biomassa sen sijaan luetaan hiilidioksidineutraaleihin energianlähteisiin. Biopolttoaineiden käytössä tosin vapautuu typpi- ja rikkioksideja, jotka edesauttavat maaperän ja merien happamoitumista. Lisäksi biopolttoaineen rikki voi sekä vähentää että aiheuttaa laitteiden korroosiota energiantuotannossa riippuen biopolttoaineesta ja palamisesta. Tämän työn päätavoitteena oli selvittää mitä biopolttoaineeseen sitoutuneelle typelle ja rikille tapahtuu teollisissa polttolaitoksissa. Kyseisten oksidien muodostumista tutkittiin polttamalla eri biomassoja polttolaitoksissa. Tutkimukset toteutettiin mittauskampanjoilla useissa polttolaitoksissa. Kaasujen koostumusta mitattiin sekä tulipesässä, että savukaasuista. Kaasujen koostumus varsinkin tulipesässä on tärkeää, jotta tulevaisuudessa voidaan rakentaa puhtaampia ja tehokkaampia polttolaitoksia. Työn toisena tavoitteena oli selvittää biomassan polton yhteydessä tapahtuvaa tuhkan sulfatoitumista. Alkalikloridit, joita muodostuu biomassan poltossa, voivat aiheuttaa lämmönsiirtopintojen korroosiota. Rikki osoittautui tärkeäksi osaksi prosessia, jossa korroosiota aiheuttavat alkalikloridit sulfatoituivat vähemmän korrosoiviksi alkalisulfaateiksi. Myös kaasumaisen rikkihapon läsnäoloa savukaasuissa tutkittiin. On todettu, että kaasumuotoinen rikkihappo johtaa korroosioon savukaasukanavan kylmässä päässä ja sen eri osissa rikkihapon tiivistyessä lämpötilan laskiessa. Mikäli rikkihapon pitoisuus savukaasussa tiedetään, sen kastepiste voidaan laskea ja tiivistyminen estää. Tässä työssä kehitettiin mittausmenetelmä rikkihapon alhaisten pitoisuuksien mittaamiseen. Menetelmää hyödynnettiin polttolaitoksissa, joissa tutkittiin rikkihapon tiivistymisestä johtuvaa korroosiota.

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Poster at Open Repositories 2014, Helsinki, Finland, June 9-13, 2014

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Presentation at the 12th Bibliotheca Baltica Symposium at Södertörn University Library

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The National Library of Finland is implementing the Digitization Project of Kindred Languages in 2012–16. Within the project we will digitize materials in the Uralic languages as well as develop tools to support linguistic research and citizen science. Through this project, researchers will gain access to new corpora 329 and to which all users will have open access regardless of their place of residence. Our objective is to make sure that the new corpora are made available for the open and interactive use of both the academic community and the language societies as a whole. The project seeks to digitize and publish approximately 1200 monograph titles and more than 100 newspapers titles in various Uralic languages. The digitization will be completed by the early of 2015, when the Fenno-Ugrica collection would contain around 200 000 pages of editable text. The researchers cannot spend so much time with the material that they could retrieve a satisfactory amount of edited words, so the participation of a crowd in editing work is needed. Often the targets in crowdsourcing have been split into several microtasks that do not require any special skills from the anonymous people, a faceless crowd. This way of crowdsourcing may produce quantitative results, but from the research’s point of view, there is a danger that the needs of linguistic research are not necessarily met. Also, the number of pages is too high to deal with. The remarkable downside is the lack of shared goal or social affinity. There is no reward in traditional methods of crowdsourcing. Nichesourcing is a specific type of crowdsourcing where tasks are distributed amongst a small crowd of citizen scientists (communities). Although communities provide smaller pools to draw resources, their specific richness in skill is suited for the complex tasks with high-quality product expectations found in nichesourcing. Communities have purpose, identity and their regular interactions engenders social trust and reputation. These communities can correspond to research more precisely. Instead of repetitive and rather trivial tasks, we are trying to utilize the knowledge and skills of citizen scientists to provide qualitative results. Some selection must be made, since we are not aiming to correct all 200,000 pages which we have digitized, but give such assignments to citizen scientists that would precisely fill the gaps in linguistic research. A typical task would editing and collecting the words in such fields of vocabularies, where the researchers do require more information. For instance, there’s a lack of Hill Mari words in anatomy. We have digitized the books in medicine and we could try to track the words related to human organs by assigning the citizen scientists to edit and collect words with OCR editor. From the nichesourcing’s perspective, it is essential that the altruism plays a central role, when the language communities involve. Upon the nichesourcing, our goal is to reach a certain level of interplay, where the language communities would benefit on the results. For instance, the corrected words in Ingrian will be added onto the online dictionary, which is made freely available for the public and the society can benefit too. This objective of interplay can be understood as an aspiration to support the endangered languages and the maintenance of lingual diversity, but also as a servant of “two masters”, the research and the society.