Táto práca sa zaoberá technikou výroby samousporiadaných nanoštruktúr pre elektrické aplikácie. Prototypy boli pripravené anodickou oxidáciou v dvoch dĺžkach a tromi rôznymi tepelnými úpravami. Štrukturálna charakterizácia bola spravená pomocou techniky SEM, TEM a EDX a vyhodnotenie nielen z štrukturálneho, ale aj z materiálového hľadiska. Jedinečná koreňová štruktúra samousporiadaných nanotyčiniek bola vyhodnotená a porovnaná po troch rôznych tepelných úpravách: po anodizácii, po vákuovom žíhaní, a po žíhaní vo vzduchu. Všetky prototypy obsahujú nanotyčinky s amorfnou štruktúrou, ale našli sa však aj nanokryštály pod koreňovými štruktúrami. Elektrická charakterizácia prototypov ukázala: odporové spínacie správanie (RS), diódové charakteristiky a charakteristiku podobnú pre diódy s kapacitorom. Aktívny povrch pre spínací mechanizmus je v hornej časti nanoštruktúr na rozhraní nanotyčiniek a zlatej elektródy. Výška Schottkyho bariéry na rozhraní Ti / TiO2 bola vypočítaná dvoma spôsobmi a pre všetky tri zariadenia bola nižšia ako 1,11 eV.

L'augmentation du pouvoir électrocatalytique d'une pile à combustible fonctionnant à haute température (SOFC, Solid Oxide Fuel Cell) passe notamment par l'amélioration des performances de la cathode. A cet effet, notre objectif a été de créer puis mesurer une conductivité mixte (électronique ou ionique) au sein de nouveaux oxydes de structure perovskite ABO3-d. Une étude fondamentale a été menée sur des composés choisis en fonction de l'état de valence et de la taille du cation B et du taux de lacunes d. La caractérisation des propriétés de transport (électronique et ionique) a été réalisée à l'aide de techniques nouvelles au laboratoire (meusure de la diffusion de 18O). Par la suite une corrélation entre les deux types de conductivité et les propriétés physico-chimiques des matériaux (paramètres de maille, polarisabilité des ions, ...) a été proposée.

A central nervous system (CNS) can be invaded by plenty of parasites, including parasitic helminths. Host's immune response during such infections includes not only participation of peripheral lymphocytes, but also astrocytes and microglia, resident glial cells present in the CNS. Activation of astrocytes and microglia has been recently demonstrated also in mice infected by neurotropic avian trematode Trichobilharzia regenti (Digenea: Schistosomatidae) for which mammals represent accidental hosts. The parasite does not mature in them and elicits development of inflammatory reaction in the CNS which may take part in parasite's destruction. Employing in vitro experiments, this thesis aimed at evaluation of the possible role of astrocytes and microglia in murine immune response to T. regenti. For this purpose, primary astrocyte and microglia culture preparations were established and the cells were then stimulated by antigens of T. regenti (homogenate of transformed cercariae, recombinant cathepsins B1.1 and B2). After that, production of nitric oxide and proinflammatory cytokines (IL-1 beta, IL-6, TNF-alpha) was measured. The results revealed that in vitro stimulated astrocytes and microglia increase production of nitric oxide, IL-6 and TNF-alpha. Such response to parasite's antigens could influence...

Title: Nitric oxide and its neurophysiologic role Objectives: The main aim of my diploma work is to evaluate the role of nitric oxide and its effects during epileptic seizure in rats. I summarize the present knowledge about nitric oxide and its effects on human organism in the theoretical section of this paper and I will suppose the positive effect of nitric oxide inhibitor in epileptic seizures in rats by the realization of my experiment. Methods: The experiment will be performed in the laboratory of Academy of Science of Czech Republic. Implementation will come through examining a set of ten rats. The first six will be given v (L-NPA) in an amount of 0,5mg to one side, which will take place by applying bilaterally to coele. Then after ten minutes 0,5µl of 4-aminopyridine (4-AP) will be applied bilaterally to coele. The control group, consisting of four rats will be given saline instead of L-NPA. The experiment will run for two days. Results: The course of epileptic seizure with application of L-NPA to examined group was compared with the control group. The experiment confirmed the positive effect of L-NPA in terms of delay and reduction of seizure. Keywords: nitric oxide, Nω -propyl-l-arginine, neurovascular coupling, 4-anopyridine, epilepsy

v angličtině (English abstract) Tobacco male gametophyte has a strongly dehydrated cytoplasm and represents a metabolically inactive stage. Upon cytoplasm rehydration, pollen grain becomes metabolically active and after the activation is finished, the pollen tube growth through a selected pollen aperture starts. The rehydration together with metabolic activation are accompanied by the regulation of translation and post-translational modifications (mainly phosphorylation) of the existing proteins. In this Ph.D. thesis, there were identified phosphopeptides from tobacco (Nicotiana tabacum) mature pollen, pollen activated in vitro 5 min and pollen activated in vitro 30 min. The total proteins from the above male gametophyte stages were extracted. The protein extract was trypsinized and the acquired peptide mixture was enriched by MOAC (metal oxide/hydroxide affinity chromatography) with titanium dioxide matrix. The enriched fraction was subjected to liquid chromatography coupled with tandem mass spectrometry (LC- MS/MS). Totally, there were identified 471 phosphopeptides, carrying 432 exactly localized phosphorylation sites. The acquired peptide identifications were mapped to 301 phosphoproteins that were placed into 13 functional categories, dominant of which were transcription, protein synthesis,...

O presente estudo teve como objetivo caracterizar as alterações histológicas de pele, linfonodo e baço, determinar a densidade de parasitas e de células iNOS+, assim como correlacionar o parasitismo com a expressão de iNOS em pele, baço e linfonodo de cães naturalmente acometidos por leishmaniose visceral. Foram selecionados aleatoriamente, 28 cães infectados com Leishmania (Leishmania) infantum chagasi, oriundos do Centro de Controle de Zoonoses do município de Araçatuba, os quais foram distribuídos em dois grupos, de acordo com sinais clínicos e exames laboratoriais, em sintomáticos (n=18) e assintomáticos (n=10). Um grupo de 6 animais oriundos de área não endêmica para leishmaniose visceral foram empregados como controle negativo. As alterações histológicas de pele foram similares em ambos os grupos clínicos, sintomáticos e assintomáticos, e se caracterizaram por um infiltrado inflamatório na derme, formado por células mononucleares (macrófagos, linfócitos e plasmócitos), que variou de discreto a intenso. No linfonodo, as alterações histológicas foram também semelhantes entre os grupos clínicos, e se caracterizaram por hiperplasia e hipertrofia da área cortical e para-cortical, que variou de discreta a intensa; e por hiperplasia e hipertrofia de macrófagos na região medular, caracterizando em muitos casos uma linfadenite granulomatosa. No baço, alterações histológicas da polpa branca e polpa vermelha foram similares entre os grupos sintomáticos e assintomáticos, com hipoplasia e atrofia de polpa branca e, hipertorfia e hiperplasia de macrófagos na polpa vermelha, variando de moderado a intenso. Quanto ao número de formas amastigotas/mm2 tanto na pele, como no linfonodo e baço, não houve diferença estatisticamente significativa entre os grupos clínicos (p=0,2104), (p=0,2401) e (p=0,8869), respectivamente. Em relação à densidade de células iNOS+(células/mm2), observamos que a infecção por Leishmania levou ao aumento do número destas células na pele, no baço e no linfonodo em relação ao controle (p < 0,05). Porém, quando analisamos a densidade de células iNOS+ entre os grupos clínicos, sintomáticos e assintomáticos, não observamos diferença significativa tanto na pele (p=0,3026), como em linfonodo (p=0,3257) e baço (p=0,5940). Observou-se correlação fraca e não significativa entre a densidade de parasitas e a densidade de células expressando iNOS+ no tegumento; porém no linfonodo, verificou-se correlação negativa moderada e significante (p=0,0034) entre o parasitismo e a expressão de células iNOS+, assim como no baço (p=0,0329), sugerindo que o óxido nítrico deve exercer um papel importante no controle do parasitismo em vísceras / The present study aimed the characterization the histological features in skin, lymph nodes and spleen; determination of the parasitism density and the cells expressing iNOS; and correlation between the parasitism and the expression of iNOS in the skin, lymph nodes and spleen of dogs naturally committed by visceral leishmaniasis. Twenty-eight naturally infected dogs by Leishmania (Leishmania) infantum chagasi were selected randomly from the Zoonosis Control Center of Araçatuba municipality and distributed in two groups according to the clinical signs and laboratory exams, symptomatic (n=18) and asymptomatic (n=10) animals. A group of six animals from non-endemic region for visceral leishmaniais was used as negative control. Histological changes in skin were similar in both clinical groups, symptomatic and asymptomatic, and were characterized by a focal and diffuse inflammatory infiltrate in the dermis of mononuclear cells (macrophages, lymphocytes, plasmocytes), that varied from discrete to intense. In lymph nodes, the histological changes were also similar in both clinical groups, and were characterized by hyperplasia and hypertrophy of the cortical and para-cortical area, that varied from discrete to intense; and hyperplasia and hypertrophy of macrophages in the medullar region characterizing in many cases a granulomatous lymphadenitis. In spleen, the histological alterations in the white pulp and red pulp were similar in both clinical groups, with hypoplasia and hypotrophy of the white pulp and hypertrophy and hyperplasia of macrophages in red pulp varying from moderate to intense. Regarding the results of parasitism density (amastigotes/mm2), we did not observe any significant difference between the clinical groups in skin (p=0.2104), lymph nodes (p=0.2401) and spleen (p=0.8869). Concerning to the density of iNOS+ cells, we observed that the infection by Leishmania caused an increase in the number of these cells in the skin, in spleen and lymph nodes in relation to the control group (p < 0.05). However, when we analyzed the density (cells /mm2) of iNOS+ expressing cells in clinical groups, symptomatic and asymptomatic, we did not observe any significant difference in the skin (p=0.3026), in lymph nodes (p=0.3257) and spleen (p=0.5940). A weak and non-significant correlation was observed between the parasite density and the density of iNOS+ cells in the skin. However, in the lymph node a significant and moderate correlation (p=0.0034) was observed between the parasitism and iNOS+ cells, as well as in the spleen (p=0.0329), suggesting that nitric oxide plays an important role in the control of the parasitism in the viscera

O presente estudo teve como objetivo caracterizar as alterações histológicas de pele, linfonodo e baço, determinar a densidade de parasitas e de células iNOS+, assim como correlacionar o parasitismo com a expressão de iNOS em pele, baço e linfonodo de cães naturalmente acometidos por leishmaniose visceral. Foram selecionados aleatoriamente, 28 cães infectados com Leishmania (Leishmania) infantum chagasi, oriundos do Centro de Controle de Zoonoses do município de Araçatuba, os quais foram distribuídos em dois grupos, de acordo com sinais clínicos e exames laboratoriais, em sintomáticos (n=18) e assintomáticos (n=10). Um grupo de 6 animais oriundos de área não endêmica para leishmaniose visceral foram empregados como controle negativo. As alterações histológicas de pele foram similares em ambos os grupos clínicos, sintomáticos e assintomáticos, e se caracterizaram por um infiltrado inflamatório na derme, formado por células mononucleares (macrófagos, linfócitos e plasmócitos), que variou de discreto a intenso. No linfonodo, as alterações histológicas foram também semelhantes entre os grupos clínicos, e se caracterizaram por hiperplasia e hipertrofia da área cortical e para-cortical, que variou de discreta a intensa; e por hiperplasia e hipertrofia de macrófagos na região medular, caracterizando em muitos casos uma linfadenite granulomatosa. No baço, alterações histológicas da polpa branca e polpa vermelha foram similares entre os grupos sintomáticos e assintomáticos, com hipoplasia e atrofia de polpa branca e, hipertorfia e hiperplasia de macrófagos na polpa vermelha, variando de moderado a intenso. Quanto ao número de formas amastigotas/mm2 tanto na pele, como no linfonodo e baço, não houve diferença estatisticamente significativa entre os grupos clínicos (p=0,2104), (p=0,2401) e (p=0,8869), respectivamente. Em relação à densidade de células iNOS+(células/mm2), observamos que a infecção por Leishmania levou ao aumento do número destas células na pele, no baço e no linfonodo em relação ao controle (p < 0,05). Porém, quando analisamos a densidade de células iNOS+ entre os grupos clínicos, sintomáticos e assintomáticos, não observamos diferença significativa tanto na pele (p=0,3026), como em linfonodo (p=0,3257) e baço (p=0,5940). Observou-se correlação fraca e não significativa entre a densidade de parasitas e a densidade de células expressando iNOS+ no tegumento; porém no linfonodo, verificou-se correlação negativa moderada e significante (p=0,0034) entre o parasitismo e a expressão de células iNOS+, assim como no baço (p=0,0329), sugerindo que o óxido nítrico deve exercer um papel importante no controle do parasitismo em vísceras / The present study aimed the characterization the histological features in skin, lymph nodes and spleen; determination of the parasitism density and the cells expressing iNOS; and correlation between the parasitism and the expression of iNOS in the skin, lymph nodes and spleen of dogs naturally committed by visceral leishmaniasis. Twenty-eight naturally infected dogs by Leishmania (Leishmania) infantum chagasi were selected randomly from the Zoonosis Control Center of Araçatuba municipality and distributed in two groups according to the clinical signs and laboratory exams, symptomatic (n=18) and asymptomatic (n=10) animals. A group of six animals from non-endemic region for visceral leishmaniais was used as negative control. Histological changes in skin were similar in both clinical groups, symptomatic and asymptomatic, and were characterized by a focal and diffuse inflammatory infiltrate in the dermis of mononuclear cells (macrophages, lymphocytes, plasmocytes), that varied from discrete to intense. In lymph nodes, the histological changes were also similar in both clinical groups, and were characterized by hyperplasia and hypertrophy of the cortical and para-cortical area, that varied from discrete to intense; and hyperplasia and hypertrophy of macrophages in the medullar region characterizing in many cases a granulomatous lymphadenitis. In spleen, the histological alterations in the white pulp and red pulp were similar in both clinical groups, with hypoplasia and hypotrophy of the white pulp and hypertrophy and hyperplasia of macrophages in red pulp varying from moderate to intense. Regarding the results of parasitism density (amastigotes/mm2), we did not observe any significant difference between the clinical groups in skin (p=0.2104), lymph nodes (p=0.2401) and spleen (p=0.8869). Concerning to the density of iNOS+ cells, we observed that the infection by Leishmania caused an increase in the number of these cells in the skin, in spleen and lymph nodes in relation to the control group (p < 0.05). However, when we analyzed the density (cells /mm2) of iNOS+ expressing cells in clinical groups, symptomatic and asymptomatic, we did not observe any significant difference in the skin (p=0.3026), in lymph nodes (p=0.3257) and spleen (p=0.5940). A weak and non-significant correlation was observed between the parasite density and the density of iNOS+ cells in the skin. However, in the lymph node a significant and moderate correlation (p=0.0034) was observed between the parasitism and iNOS+ cells, as well as in the spleen (p=0.0329), suggesting that nitric oxide plays an important role in the control of the parasitism in the viscera

<p>Rapporten beskriver en undersökning rörande två olika typer av inre fel, centrumfel och ytnära fel, på valsar. Examensarbete för högskoleingenjörsexamen i maskinteknik (22.5p) vid Instutitionen för ingenjörsvetenskap, fysik och matematik, Karlstad Universitet. Utfört på uppdrag av Scana Steel Björneborg AB.</p><p>Scana Björneborg är en av Europas ledande producenter av tunga friformsmidda detaljer och har eget stålverk, egen smedja, värmebehandlingsanläggning och maskinpark. På Scana Björneborg gjuts göt av järnskrot, varpå de smids, värmebehandlas och maskinbearbetas till valsar. Efter maskinbearbetning kontrolleras valsarna med ultraljud för att hitta eventuella inre fel. Specifikationerna från kund för hur stora indikationer får vara är strama och stora kostnader uppstår i samband med reklamationer, kassationer, omarbeten och förseningar. Felen har blivit alltmer frekventa och Scana Björneborg har satt samman två projektgrupper för att få försöka få bukt på dem. Examensarbetet skall understödja båda dessa grupper och genom undersökningen skapa underlag för vidare beslut. Undersökningen delades in i tre olika moment:</p><p>* Statistik och information som kunde användas för att hitta eventuella samband och orsaker till de olika feltyperna samlades i en databas.</p><p>* Den samlade statistiken och informationen organiserades, förenklades och analyserades sedan med hjälp av programmet SIMCA, ett program gjort för multivariata analyser av stora datamängder. Eventuella samband granskades och analyserades därefter manuellt för att väga och gallra resultatet .</p><p>* Sex ytnära fel i tre olika detaljer öppnades upp för kartläggning av vilken typ av defekter det rörde sig om, och en metallografisk undersökning i ljus- och svepelektronmikroskop och analys av defekternas sammansättning gjordes.</p><p>SIMCA-analys av insamlad statistik med avseende på centrumfel och vidare granskning och analys av dess resultat antyder att hög smidesvikt, hög Vanadinhalt, stukning, hög nedsmidningsgrad och smidestid per ton i den följden är viktiga faktorer vid uppkomsten av centrumfel, och att en viss samverkan finns mellan dem.</p><p>SIMCA-analys av insamlad statistik med avseende på ytnära fel och vidare granskning och analys av dess resultat antyder att ett samband mellan valda parametrar och uppkomsten av ytnära fel inte går att hitta. Metoden bedöms olämplig för vidare undersökning av ytnära fel.</p><p>Den metallografiska undersökningen av öppnade ytnära defekter visade att samtliga sex defekter liknade varandra till utseende och sammansättning. Vanligaste beståndsdelarna i dessa inneslutningar var Aluminium tillsammans med förhöjda halter av Kol och Syre. Dessa ämnen är alla naturliga i stålet och därför bedöms inte de ytnära felen vara utifrån kommande.</p> / <p>The report describes an investigation concerning two types of internal defects, axis-centered defects and near-surface defects, in rolls. Thesis for bachelor’s degree in mechanical engineering (22.5p), at the institution for engineering, physics and mathematics, Karlstad University. Ordered by Scana Steel Björneborg AB.</p><p>Scana Steel Björneborg AB is one of Europe’s leading producers of heavy free-form forgings and has its own steel plant, forge, heating treatment facility and machine park. Scana Steel Björneborg AB casts ingots from iron scrap. The ingots are then forged, heat treated and machined into rolls. After the machining the rolls are tested with ultrasonic testing equipment to look for indications of internal defects. The specifications on how big the indications are allowed to be from the client are rigid and large costs come up because of reclamations, discarding, reworking and delays. The defects have become increasingly more frequent and Scana Steel Björneborg AB has put together two groups to try and get control over the problem. The thesis is meant to support the two groups by investigating the internal defects, and to create a platform to take further decisions from. The investigation was made up of three parts:</p><p>* Statistics and information that could be used to find connections and cause of the internal defects was gathered in a data base.</p><p>* The gathered statistics and information was organized, simplified and analyzed with SIMCA, a computer software made for multivariate analyzing of large amounts of information. The results of the SIMCA-simulation were then checked further manually to weigh and lay down the fairness of the results.</p><p>* Six near-surface defects in three parts were opened up to map the types of defects and a metallographic examination in optical microscope, scanning electron microscope and spectrometer analysis of the defects’ composition was made.</p><p>The SIMCA analysis of gathered statistics concerning axis-centered defects and later manual analysis of the results showed that high forging weight, high Vanadium content, high degree of forging and low forging-time per tonne all relate to the creation of axis-centered defects, and that some interaction is present between them.</p><p>The SIMCA analysis concerning near-surface defects showed that the chosen parameters do not relate with the creation of near-surface defects. The method is deemed unsuitable for further investigations.</p><p>The metallographic examination of the six near-surface defects showed that all six defects resemble each other in appearance and composition. The most common elements in these inclusions are Aluminum and heightened contents of Carbon and Oxygen. These elements are all naturally occurring elements in the steel and because of this the inclusions are not thought to be exogenous.</p>

Die hohe thermische Belastung des Lichtbogens während des Schaltvorganges bewirkt ein Aufschmelzen des Kontaktwerkstoffes. Für einen kurzen Augenblick schwimmen Metalloxidpartikel in einem Bereich geschmolzenen Silbers. Dies hat eine Gefügeumordnung zur Folge, welche die Eigenschaften des Kontaktes beeinflussen. Die Zielstellung der vorliegenden Arbeit besteht darin, einen Beitrag zur Erweiterung des Verständnisses von Ag/SnO2-Werkstoffen zu leisten, um die Entwicklung neuer und optimierter Kontaktwerkstoffe voranzutreiben und nachhaltig den Einsatz von Umweltressourcen wie Werkstoffe (Edelmetallgehalt) und Energie zu verringern. Dabei nimmt die Gefügecharakterisierung von ungeschalteten und geschalteten Ag/SnO2-Kontaktwerkstoffen einen wichtigen Stellenwert ein. Die Ausbildung der Kontaktoberfläche und die Ausprägung der Gefügeumordnung (sog. Schaltgefüge) werden in Abhängigkeit der Schaltversuchsart, der Werkstoffzusammensetzung und der Herstellroute der Kontaktwerkstoffe charakterisiert. Ein wesentlicher Bestandteil der Arbeit ist die Untersuchung der Kontaktoberfläche und metallographischer Schliffe (Ionenstrahl poliert) von mehrfach geschalteten Kontakten (≥ 1000 Schaltungen) mittels FE-REM, um anschließend Zusammenhänge zwischen dem Ausgangsgefüge, dem Schaltgefüge und den Schalteigenschaften zu ermitteln. Dazu wird unter anderem die Wirkung der oxidischen Zusätze durch Benetzungsversuche von Ag auf Metalloxidsubstraten experimentell bestimmt. Des Weiteren wird die Schädigung des Werkstoffes durch die reine Lichtbogenbelastung mittels Laufschienenversuchen untersucht, wodurch das Laufverhalten des Lichtbogens und die Bildung der Anoden- und Kathodenkrater in Abhängigkeit des Werkstoffes untersucht werden kann. / During the switching process the contact material is melting. For a short time (about 10 ms) metal oxide particles will be swimming in liquid silver resulting in structural changes which will effect the properties of the contact materials. The goal of this investigation is to contribute to an improvement of knowledge about Ag/SnO2 contact materials in order to promote the development of new and improved contact materials to strongly reduce the stake of environmental resources like materials (precious metal content) and energy. The microstructure characterization of unswitched and switched Ag/SnO2-materials is the significant part of this study. The formation of the contact surface and the structural changes are investigated depending on several switching experiments, material composition and manufacturing process. An essential part of this work is to analyze the contact surface and the changes of the microstructure of multi-switched contacts (number of switches ≥ 1000) by FE-SEM. In order to identify relations between the bulk microstructure, the charged microstructure and switching behaviour. Furthermore, the effects of the oxide additives are investigated by wetting experiments of Ag on the metal oxide substrate. The erosion of the contact material is reviewed by using a running rails experiment with pure arc loading. Thereby it is possible to research the running arc behaviour and the formation of the anode and cathode craters depending on the contact material.

Rapporten beskriver en undersökning rörande två olika typer av inre fel, centrumfel och ytnära fel, på valsar. Examensarbete för högskoleingenjörsexamen i maskinteknik (22.5p) vid Instutitionen för ingenjörsvetenskap, fysik och matematik, Karlstad Universitet. Utfört på uppdrag av Scana Steel Björneborg AB. Scana Björneborg är en av Europas ledande producenter av tunga friformsmidda detaljer och har eget stålverk, egen smedja, värmebehandlingsanläggning och maskinpark. På Scana Björneborg gjuts göt av järnskrot, varpå de smids, värmebehandlas och maskinbearbetas till valsar. Efter maskinbearbetning kontrolleras valsarna med ultraljud för att hitta eventuella inre fel. Specifikationerna från kund för hur stora indikationer får vara är strama och stora kostnader uppstår i samband med reklamationer, kassationer, omarbeten och förseningar. Felen har blivit alltmer frekventa och Scana Björneborg har satt samman två projektgrupper för att få försöka få bukt på dem. Examensarbetet skall understödja båda dessa grupper och genom undersökningen skapa underlag för vidare beslut. Undersökningen delades in i tre olika moment: * Statistik och information som kunde användas för att hitta eventuella samband och orsaker till de olika feltyperna samlades i en databas. * Den samlade statistiken och informationen organiserades, förenklades och analyserades sedan med hjälp av programmet SIMCA, ett program gjort för multivariata analyser av stora datamängder. Eventuella samband granskades och analyserades därefter manuellt för att väga och gallra resultatet . * Sex ytnära fel i tre olika detaljer öppnades upp för kartläggning av vilken typ av defekter det rörde sig om, och en metallografisk undersökning i ljus- och svepelektronmikroskop och analys av defekternas sammansättning gjordes. SIMCA-analys av insamlad statistik med avseende på centrumfel och vidare granskning och analys av dess resultat antyder att hög smidesvikt, hög Vanadinhalt, stukning, hög nedsmidningsgrad och smidestid per ton i den följden är viktiga faktorer vid uppkomsten av centrumfel, och att en viss samverkan finns mellan dem. SIMCA-analys av insamlad statistik med avseende på ytnära fel och vidare granskning och analys av dess resultat antyder att ett samband mellan valda parametrar och uppkomsten av ytnära fel inte går att hitta. Metoden bedöms olämplig för vidare undersökning av ytnära fel. Den metallografiska undersökningen av öppnade ytnära defekter visade att samtliga sex defekter liknade varandra till utseende och sammansättning. Vanligaste beståndsdelarna i dessa inneslutningar var Aluminium tillsammans med förhöjda halter av Kol och Syre. Dessa ämnen är alla naturliga i stålet och därför bedöms inte de ytnära felen vara utifrån kommande. / The report describes an investigation concerning two types of internal defects, axis-centered defects and near-surface defects, in rolls. Thesis for bachelor’s degree in mechanical engineering (22.5p), at the institution for engineering, physics and mathematics, Karlstad University. Ordered by Scana Steel Björneborg AB. Scana Steel Björneborg AB is one of Europe’s leading producers of heavy free-form forgings and has its own steel plant, forge, heating treatment facility and machine park. Scana Steel Björneborg AB casts ingots from iron scrap. The ingots are then forged, heat treated and machined into rolls. After the machining the rolls are tested with ultrasonic testing equipment to look for indications of internal defects. The specifications on how big the indications are allowed to be from the client are rigid and large costs come up because of reclamations, discarding, reworking and delays. The defects have become increasingly more frequent and Scana Steel Björneborg AB has put together two groups to try and get control over the problem. The thesis is meant to support the two groups by investigating the internal defects, and to create a platform to take further decisions from. The investigation was made up of three parts: * Statistics and information that could be used to find connections and cause of the internal defects was gathered in a data base. * The gathered statistics and information was organized, simplified and analyzed with SIMCA, a computer software made for multivariate analyzing of large amounts of information. The results of the SIMCA-simulation were then checked further manually to weigh and lay down the fairness of the results. * Six near-surface defects in three parts were opened up to map the types of defects and a metallographic examination in optical microscope, scanning electron microscope and spectrometer analysis of the defects’ composition was made. The SIMCA analysis of gathered statistics concerning axis-centered defects and later manual analysis of the results showed that high forging weight, high Vanadium content, high degree of forging and low forging-time per tonne all relate to the creation of axis-centered defects, and that some interaction is present between them. The SIMCA analysis concerning near-surface defects showed that the chosen parameters do not relate with the creation of near-surface defects. The method is deemed unsuitable for further investigations. The metallographic examination of the six near-surface defects showed that all six defects resemble each other in appearance and composition. The most common elements in these inclusions are Aluminum and heightened contents of Carbon and Oxygen. These elements are all naturally occurring elements in the steel and because of this the inclusions are not thought to be exogenous.