Atomic level phenomena on transition metal surfaces

In this study we discuss the atomic level phenomena on transition metal surfaces. Transition metals are widely used as catalysts in industry. Therefore, reactions occuring on transition metal surfaces have large industrial intrest. This study addresses problems in very small size and time scales, which is an important part in the overall understanding of these phenomena. The publications of this study can be roughly divided into two categories: The adsorption of an O2 molecule to a surface, and surface structures of preadsorbed atoms. These two categories complement each other, because in the realistic case there are always some preadsorbed atoms at the catalytically active surfaces. However, all transition metals have an active d-band, and this study is also a study of the in uence of the active d-band on other atoms. At the rst part of this study we discuss the adsorption and dissociation of an O2 molecule on a clean stepped palladium surface and a smooth palladium surface precovered with sulphur and oxygen atoms. We show how the reactivity of the surface against the oxygen molecule varies due to the geometry of the surface and preadsorbed atoms. We also show how the molecular orbitals of the oxygen molecule evolve when it approaches the di erent sites on the surface. In the second part we discuss the surface structures of transition metal surfaces. We study the structures that are intresting on account of the Rashba e ect and charge density waves. We also study the adsorption of suphur on a gold surface, and surface structures of it. In this study we use ab-initio based density functional theory methods to simulate the results. We also compare the results of our methods to the results obtained with the Low-Energy-Electron-Difraction method.

Modelos de transferência de metal pesado na cana-de-açúcar adubada com composto de lixo urbano

A pesquisa aborda a reciclagem do composto de lixo urbano (CLU) como fertilizante alternativo na cana-de-açúcar e como solução social e ambiental ao acúmulo de resíduos sólidos nos centros urbanos. Utilizou-se da modelagem matemática para conhecer a dinâmica dos metais pesados, visando ao estabelecimento de critérios e procedimentos para o uso seguro do CLU, limitado pela quantidade desses elementos. Foram construídos modelos compartimentais a partir de dados de experimentos em condições controladas e parcialmente validados com dados de campo. Esse modelo descreveu a transferência de metais pesados no sistema solo-raiz-parte aérea para a cana-de-açúcar. Pôde-se concluir, pelas condições desta pesquisa, que o metal mais preocupante foi o níquel, pois demora, aproximadamente, três anos para ser atenuado no solo e chega em maior quantidade na parte aérea. Quanto aos fatores argila, óxidos e pH do solo, notou-se que, nos solos de maior poder tampão, a passagem da maioria dos metais foi mais lenta. Esse modelo pode tornar-se importante aliado na definição de leis de utilização do CLU, visando à não-contaminação ambiental, redução no acúmulo de lixo e de custos de produção.

Horizontal pressures in cylindrical metal silos and comparison with different international standards

The focus of this research was to evaluate the horizontal pressures on a cylindrical metal silo of corrugated walls and flat bottom with 1.82m diameter and 5.4m high, and to compare the values with those obtained theoretically by the ISO 11697, EP 433 and AS 3774 standards. The silo was symmetrically filled and constant speed with wheat cv. soft red for two different height/diameter ratios (H/D) and was unloaded through three orifices with a diameter of 71.6mm, one concentric and two eccentrics. Horizontal pressures were measured on the walls of the silo at three positions using hydraulic type pressure cells. The results showed that shortly after the start of the unloading, there was a mass flow above the quota of H/D = 1.2, whereas below this quota funnel flow occurred. It can be said that the EP 433 standard was more appropriate to predict horizontal pressures in silos in H/D ratio = 1.0, with eccentric unloading. For the H/D ratio = 1.5, AS 3774 standard was the one that produced values closer to the experimental.

Development of simple and efficient synthetic strategies for production of fine chemicals of pharmaceutical relevance : metal-mediated allylation combined with applied catalysis

Den snart 200 år gamla vetenskapsgrenen organisk synteskemi har starkt bidragit till moderna samhällens välfärd. Ett av flaggskeppen för den organiska synteskemin är utvecklingen och produktionen av nya läkemedel och speciellt de aktiva substanserna däri. Därmed är det viktigt att utveckla nya syntesmetoder, som kan tillämpas vid framställningen av farmaceutiskt relevanta målstrukturer. I detta sammanhang är den ultimata målsättningen dock inte endast en lyckad syntes av målmolekylen, utan det är allt viktigare att utveckla syntesrutter som uppfyller kriterierna för den hållbara utvecklingen. Ett av de centralaste verktygen som en organisk kemist har till förfogande i detta sammanhang är katalys, eller mera specifikt möjligheten att tillämpa olika katalytiska reaktioner vid framställning av komplexa målstrukturer. De motsvarande industriella processerna karakteriseras av hög effektivitet och minimerad avfallsproduktion, vilket naturligtvis gynnar den kemiska industrin samtidigt som de negativa miljöeffekterna minskas avsevärt. I denna doktorsavhandling har nya syntesrutter för produktion av finkemikalier med farmaceutisk relevans utvecklats genom att kombinera förhållandevis enkla transformationer till nya reaktionssekvenser. Alla reaktionssekvenser som diskuteras i denna avhandling påbörjades med en metallförmedlad allylering av utvalda aldehyder eller aldiminer. De erhållna produkterna innehållende en kol-koldubbelbindning med en närliggande hydroxyl- eller aminogrupp modifierades sedan vidare genom att tillämpa välkända katalytiska reaktioner. Alla syntetiserade molekyler som presenteras i denna avhandling karakteriseras som finkemikalier med hög potential vid farmaceutiska tillämpningar. Utöver detta tillämpades en mängd olika katalytiska reaktioner framgångsrikt vid syntes av dessa molekyler, vilket i sin tur förstärker betydelsen för de katalytiska verktygen i organiska kemins verktygslåda.

Feasibility study of metal to polymer hybrid joining

The increasing demand for lightweight components has led to a huge exploitation of non-metallic materials such as polymers, fibers and elastomers in industrial and manufacturing processes. Recent trends towards cost effectiveness, weight reduction and production flexibility in industrial production and manufacturing processes has led to a growing interest in hybrid components where two or more dissimilar materials coexist to achieving specifically optimized characteristics. The importance of this research is to serve as a bridge to understanding the theories behind various joining techniques and the adaptation of the process for metal to polymer hybrid joints. Moreso, it helps companies to select the most productive and yet economical joining process for realization of lightweight metal to polymer hybrid components. This thesis is a literature review analyzing various materials that has been published on various joining methods for metal to polymer hybrid joints on the feasibility and eventual realization of the joint between these dissimilar materials. This study is aimed at theoretically evaluating the feasibility of joining processes between metal and plastic components by exploiting exhaustively joining and welding sources.

Kapearailotekniikan käyttö jauhekaarihitsauksessa

Diplomityössä tavoitteena oli tutkia kapearailojauhekaaritekniikan soveltuvuutta konepajakäyttöön ja sen vaikutusta hitsauksen tuottavuuteen sekä hitsin mekaanisiin ominaisuuksiin. Työ tehtiin vertailukokeilla, jossa koehitsaukset suoritettiin eri aineenpaksuuksille siten, että jokaiselle tutkimuksen kohteena olleelle materiaalille tehtiin yksi hitsaus käytössä olevalla jauhekaaritekniikalla, jolloin saatiin vertailukohde, johon uutta kapearailotekniikkaa verrattiin. Tulokset osoittivat, että kapearailotekniikalla 1 palko/palkokerros aineenpaksuudeltaan Pl. 60 mm koekappale saatiin hitsattua n. 39 % nopeammin verrattuna perinteiseen tandem -hitsaukseen. Kyseisellä aineenpaksuudella lisäainelangan kulutus oli n. 41 % ja jauheen kulutus n. 71 % pienempi verrattuna perinteiseen X- railohitsaukseen tandem -menetelmällä. Lisäksi tuli esille, että ”palkoa palonpäälle” -tekniikka on kapearailotekniikoista tehokkain, sillä 2 palkoa/palkokerros menetelmässä railon leveyttä jouduttiin leventämään, jolloin kapearailotekniikan pieni railotilavuus menetettiin. Lisäaineen kulutus tälläkin menetelmällä jäi pienemmäksi verrattuna X- railohitsaukseen. Ennalta pelättyä kuonan irtoamisongelmaa ei kapearailohitsauksessa havaittu, vaan kuona irtosi ongelmitta railon kyljistä. Lisäksi kapearailotekniikalla hitsattujen hitsien lujuudet olivat vertailukelpoiset tandem- ja yksilankamenetelmällä hitsattujen hitsien kanssa.

Sorption of metal ions to wood, pulp and bark materials

Ett huvudmål med denna avhandling var att erhålla ny information om växelverkan mellan metalljoner i vattenfas och träbaserade material såsom olika pappersmassor, ved och bark. Material av gran, tall och björk har studerats. En ny känslig kolonnkromatografisk metod utvecklades för bestämning av affinitetsordningar för 17 olika metalljoner. Av dessa bands trevärt järn och de mycket toxiska tungmetallerna bly, koppar och kadmium starkast till de studerade materialen. Växelverkan i dessa tvåfas system sker som jonbyte, huvudsakligen via komplexbildning av metalljoner till funktionella grupper i den fasta fasen. Vattenfasens pH är den viktigaste parametern som bestämmer totala halten av metalljoner som binds till materialen. Resultatet i denna avhandling kan delvis betraktas som grundforskning. En ny kunskap om metalljoners förekomst och kemiska reaktioner i dessa system är även av stor ekonomisk och ekologisk, betydelse, när man strävar till allt mera slutna system i moderna massafabriker. Avhandlingen visar också att trädbark har stor potential för biosorption av tungmetaller t.ex. från avfallsvatten. Trädbark har nästan lika stor bindningskapacitet som dyra syntetiska jonbytare.

Advanced welding technologies used for arctic metal structures

Rapid depletion of easy-to-access fossil fuel, predominantly, oil and gas resources has now necessitated increase in need to develop new oil and gas sources in ever more remote and hostile environments. This is necessary in order to explore more oil and gas resources to meet rapidly rising long-term energy demand in the world, both at present and in the nearest future. Arctic is one of these harsh environments, where enormous oil and gas resources are available, containing about 20% of the world total oil and gas, but the environmental conditions are very harsh and hostile. However, virtually all the facilities required for the exploration and development of this new energy source are constructed with metals as well as their alloys and are predominantly joined together by welding processes and technologies. Meanwhile, due to entirely different environment from the usual moderate temperate region, conventional welding technologies, common metals and their alloys cannot be applied as this Arctic environment demand metals structures with very high toughness and strength properties under extremely low temperature. This is due to the fact that metals transit from ductility to brittleness as the temperature moves toward extreme negative values. Hence, this research work investigates and presents the advanced welding technologies applicable to Arctic metal structures which can give satisfactory weldments under active Arctic service conditions. .

Element speciation and behaviour in metal-rich Boreal river and estuarine systems using ultrafiltration and chemical modelling

The bioavailability of metals and their potential for environmental pollution depends not simply on total concentrations, but is to a great extent determined by their chemical form. Consequently, knowledge of aqueous metal species is essential in investigating potential metal toxicity and mobility. The overall aim of this thesis is, thus, to determine the species of major and trace elements and the size distribution among the different forms (e.g. ions, molecules and mineral particles) in selected metal-enriched Boreal river and estuarine systems by utilising filtration techniques and geochemical modelling. On the basis of the spatial physicochemical patterns found, the fractionation and complexation processes of elements (mainly related to input of humic matter and pH-change) were examined. Dissolved (<1 kDa), colloidal (1 kDa-0.45 μm) and particulate (>0.45 μm) size fractions of sulfate, organic carbon (OC) and 44 metals/metalloids were investigated in the extremely acidic Vörå River system and its estuary in W Finland, and in four river systems in SW Finland (Sirppujoki, Laajoki, Mynäjoki and Paimionjoki), largely affected by soil erosion and acid sulfate (AS) soils. In addition, geochemical modelling was used to predict the formation of free ions and complexes in these investigated waters. One of the most important findings of this study is that the very large amounts of metals known to be released from AS soils (including Al, Ca, Cd, Co, Cu, Mg, Mn, Na, Ni, Si, U and the lanthanoids) occur and can prevail mainly in toxic forms throughout acidic river systems; as free ions and/or sulfate-complexes. This has serious effects on the biota and especially dissolved Al is expected to have acute effects on fish and other organisms, but also other potentially toxic dissolved elements (e.g. Cd, Cu, Mn and Ni) can have fatal effects on the biota in these environments. In upstream areas that are generally relatively forested (higher pH and contents of OC) fewer bioavailable elements (including Al, Cu, Ni and U) may be found due to complexation with the more abundantly occurring colloidal OC. In the rivers in SW Finland total metal concentrations were relatively high, but most of the elements occurred largely in a colloidal or particulate form and even elements expected to be very soluble (Ca, K, Mg, Na and Sr) occurred to a large extent in colloidal form. According to geochemical modelling, these patterns may only to a limited extent be explained by in-stream metal complexation/adsorption. Instead there were strong indications that the high metal concentrations and dominant solid fractions were largely caused by erosion of metal bearing phyllosilicates. A strong influence of AS soils, known to exist in the catchment, could be clearly distinguished in the Sirppujoki River as it had very high concentrations of a metal sequence typical of AS soils in a dissolved form (Ba, Br, Ca, Cd, Co, K, Mg, Mn, Na, Ni, Rb and Sr). In the Paimionjoki River, metal concentrations (including Ba, Cs, Fe, Hf, Pb, Rb, Si, Th, Ti, Tl and V; not typical of AS soils in the area) were high, but it was found that the main cause of this was erosion of metal bearing phyllosilicates and thus these metals occurred dominantly in less toxic colloidal and particulate fractions. In the two nearby rivers (Laajoki and Mynäjoki) there was influence of AS soils, but it was largely masked by eroded phyllosilicates. Consequently, rivers draining clay plains sensitive to erosion, like those in SW Finland, have generally high background metal concentrations due to erosion. Thus, relying on only semi-dissolved (<0.45 μm) concentrations obtained in routine monitoring, or geochemical modelling based on such data, can lead to a great overestimation of the water toxicity in this environment. The potentially toxic elements that are of concern in AS soil areas will ultimately be precipitated in the recipient estuary or sea, where the acidic metalrich river water will gradually be diluted/neutralised with brackish seawater. Along such a rising pH gradient Al, Cu and U will precipitate first together with organic matter closest to the river mouth. Manganese is relatively persistent in solution and, thus, precipitates further down the estuary as Mn oxides together with elements such as Ba, Cd, Co, Cu and Ni. Iron oxides, on the contrary, are not important scavengers of metals in the estuary, they are predicted to be associated only with As and PO4.

Fatigue study of the fillet weld waving on weld toe and the penetration in the weld root based on the effective notch stress approach

The fatigue failure of structures under fluctuating loads in fillet weld joints raises a demand to determine the parameters related to this type of loading. In this study, the stress distribution in the susceptible area of weld toe and weld root in fillet welded models analyzed by finite element method applying FEMAP software. To avoid the geometrical singularity on the path of analytical stress analysis in the toe and root area of a weld model the effective notch stress approach applied by which a proper fictitious rounding that mostly depend on the material of structure is applied. The models with different weld toe waving width and radius are analyzed while the flank angle of weld varied in 45 and 30 degrees. The processed results shows that the waving compare to the straight weld toe makes differences in the value of stress and consequently the stress concentration factor between the tip and depth of the waves in the weld toe which helps to protect the crack of propagation and gives enough time and tools to be informed of the crack initiation in the structure during the periodical observation of structure. In the weld root study the analyses among the models with the welding penetration percentage from non-penetration to the full-penetration shows a slightly increase in the root area stress value which comparing with the stiffening effect of penetration conclude that the half-penetration can make an optimization between the stress increase and stiffening effect of deep penetration.

Krigaren och transvestiten : gestaltningar av mörker och maskuliniteter i finländsk black metal

Avhandlingen undersöker gestaltningar av mörker och maskuliniteter i den finländska black metal-scenen. Normativa hegemoniska och normbrytande subversiva gestaltningar av maskuliniteter bland de mest aktiva anhängarna av den finländska black metal-scenen undersöks som uttryck för återkommande, kulturella mönster. Mönstren analyseras med hjälp av teorier om hegemonisk maskulinitet, heteronormativitet, genusperformativitet, subversivitet och protestmaskulinitet. Queerteori och (kritisk) mansforskning som har sina ursprung i feministisk forskning utgör avhandlingens teoretiska underlag. Begreppen stil och ideologi aktualiseras i en diskussion kring hur mörker, ett begrepp som är av centralt värde inom den finländska black metal-scenen, kan förstås och uttryckas av scenmedlemmarna. Mörkret, som ofta ideologimässigt består av antikristliga element, inom den finländska scenen i regel förknippade med satanism, uttrycks genom låttexter, det visuella och det musikaliska, vilka tillsammans utgör black metal-stilen.

Ohutlevyjen laserhitsaus

Tässä diplomityössä tarkasteltiin laseria ja sen käyttöä laserhitsauksessa. Laserin käyttäminen asettaa omat vaatimuksensa ja haasteet laserhitsattavan tuotteen ja mahdollisen kiinnittimen suunnittelulle. Lisäksi laserin käyttö konepajassa asettaa tiettyjä vaatimuksia työympäristölle. Diplomityössä suunniteltiin uudelleen eräs ohutlevystä valmistettava kotelo ja pyrittiin selvittämään soveltuuko se laserhitsattavaksi, ja saako kotelosta hitsattua täysin tiiviin. Kotelo soveltui hyvin laserhitsattavaksi, mutta täysin tiiviin kotelon hitsaaminen oli haasteellista ja hyvin epävarmaa.

From War Pigs to Unsung Heroes: The Criticism and Justification of War in Metal Lyrics

Tässä tutkimuksessa käsitellään heavy metal -kappaleiden sanoitusten sisältöä. Tutkimusmateriaaliin on valittu yksi teema, sota, jonka avulla avataan sanoitusten sisältöä ja merkitystä. Metallimusiikki alakulttuurina on tyylillisesti ja temaattisesti spesifi, ja sillä on omat musiikilliset tavoitteensa. Tässä tutkimuksessa tarkastellaan erityisesti sitä miten sotaa kritisoidaan tai perustellaan heavy rock -sanoituksissa. Tutkimusmateriaalini koostuu 29 englanninkielisen kappaleen sanoituksesta vuosilta 1970–2012. Edustettuina on useita ajanjaksoja sekä maita. Yhdistävänä tekijänä on englannin kielen lisäksi se, että kaikki sanoitukset käsittelevät modernia länsimaista sodankäyntiä. Tekstit valittiin sen perusteella, että niissä ilmeni positiivinen tai negatiivinen näkökulma sotaan. Tutkimus nojaa Theo van Leeuwenin legitimaatioteoriaan, joka puolestaan pohjautuu diskurssianalyysiin. Legitimaatioteoria käsittää neljä strategiaa, jotka voivat joko kritisoida tai perustella sosiaalisia käytänteitä. Ne ovat auktoriteetteihin vetoaminen, moraalinen arviointi, järkeistäminen ja mytopoeesi. Yksi tavoitteistani tutkimuksessani on selvittää legitimaatioteorian toimivuutta omassa materiaalissani. Käytän metodina lähilukua, joka mahdollistaa niiden sanojen ja ilmaisujen identifioimisen, jotka ovat näkökulmaltaan joko positiivisesti tai negatiivisesti sotaan suhtautuvia. Analyysini kannalta tärkeitä ovat sekä kieli- että kulttuurikonteksti, sillä ne määrittelevät sanojen merkityksen. Analyysin perusteella kävi ilmi, että esimerkit jakautuivat eri strategioiden välille hyvin epätasaisesti. Auktoriteetteihin vetoamisen strategiasta löytyi vain yksi esimerkki, kun taas moraalisen arvioinnin esimerkkejä oli neljätoista. Lisäksi kaikkia legitimaatioteorian alaryhmiä ei löytynyt materiaalista ollenkaan. Osalla alaryhmistä oli useita esiintymiä, mutta osalla vain yksi. Esimerkkien epätasaista jakautumista selittää mm. se, että tutkimuksen materiaalin kannalta kaikki alakategoriat eivät ole relevantteja. Jotta tutkimustuloksista saataisiin edustavampi, laajempi otanta olisi tarpeen. Legitimaatioteorian soveltuvuutta sanoituksien yhteydessä tulisi tutkia laajemmin.