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Johansson, Kenny. "Process and microstructure development of a LPBF produced maraging steel." Thesis, Karlstads universitet, Avdelningen för maskin- och materialteknik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-79004.
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Additive manufacturing (AM) has the possibility of producing complex-shaped components which can not be produced by conventional manufacturing methods. This gives the opportunity for designers to freely think outside the design spectra which is otherwise limited by conventional manufacturing methods. AM of metal has rapidly been developed for the last three decades, and they now are reaching industrial acceptance levels, metal feedstock for use in AM is also rapidly growing. AM of metals is especially of interest for the tooling industry. The design freedom which AM offers the tooling manufacturer can design complex cooling channels within moulds, which could reduce cycle time and enhance the quality of components produced with the moulds. Maraging steels have been proven to both be able to be processed with AM but also have comparable performance to traditionally carbon-based used tool steels. Laser Powder Bed Fusion (LPBF) is one of the most promising AM systems today, by using powder as a feedstock it can produce high-resolution parts without needing to process them after they have been produced. However, there is a need to better understand processing within the LPBF system. This master thesis is aimed to process a newly developed maraging steel from Uddeholm, and conduct process parameter experiment and study their correlation to be able to produce samples with as few defects possible. It is crucial to conform to a good methodology for how to find those correlations and see how they influence the printed material. LPBF process has a multi-complex variable system, and by narrowing down the complexity by focus on the most influencing parameters as has been proven by many researchers. Even with a reduced focus, it is still a multi-variable problem. In this study a methodology of finding process parameters relations, a Design Of Experiment software was used, namely, MODDE. By screening of process parameter ranges, within the software, a statistical evaluation of operational process window can be found with fewer conducted experiment. Development of process parameter can traditionally be time-consuming and result in an unnecessary large number of experiments to find the operational window. The experiment showed that laser power and point distance had the most influencing effect on relative density, followed by exposure time and hatch distance. The experiment was firstly conducted with a layer thickness of 50 µm, the achieved relative density resulted in over 99.8 percent. However, a large lack of fusion defects was observed inside the specimens. Even though a high relative density was measured, a pore analysis has to be conducted to fully understand the size and shape of defects since they can have a severe impact on mechanical properties. It was believed that the layer thickness was too high and that the defects could be reduced by printing a set with same process parameters but with a lower layer thickness of 40 µm instead. The reduction of layer thickness did result in a significant decrease of the defects observed. However, future work after this thesis must be continued to further optimize and to increase the solidity of printed material to reach closer to its conventional produced relatives<br>Additiv tillverkning har möjligheten att producera komplext konstruerade komponenter som inte kan produceras med konventionella tillverkningsmetoder. Detta ger konstruktörer möjligheten att fritt tänka utanför designspektra som annars begränsas av konventionella tillverkningsmetoder. Additiv tillverkning av metall har snabbt utvecklats under de senaste tre decennierna och har nu nått industriella acceptansnivåer. Metallråvara för användning i additiv tillverkning växer snabbt. Additiv tillverkning av metaller är särskilt intressant för verktygsindustrin, designfriheten som additiv tillverkning kan erbjuda verktygstillverkaren för att kunna utforma komplexa kylkanaler inuti formar. Det kan således reducera cykeltiden och förbättra kvaliteten på komponenter som produceras med formarna. Maråldringsststål har visat sig att både kunna processas i additiv tillverkning och har jämförbara egenskaper med traditionellt kolbaserade verktygsstål. Pulverbäddsystemet är ett av de mest lovande systemen idag, genom att använda pulver som råmaterial kan systemet producera komponenter med hög noggranhet utan att behöva bearbeta dem efter att processen är klar. Det finns emellertid ett behov av att bättre förstå själva processen inom pulverbädds teknologin. Den här masteruppsatsen syftar till att additivt tillverka ett nyutvecklat maråldringsstål från Uddeholm. Samt att genomföra processparameterexperiment och studera deras korrelation för att kunna producera prover med så få defekter som möjligt. Det är avgörande att hitta en metod för hur man hittar korrelationerna och se hur de påverkar det tillverkade materialet. Pulverbäddsystemet har ett multikomplext variabelsystem. För att minska komplexiteten kan fokus läggas på de mest inflytelserika processparametrarna, vilket har bevisats av många forskare. Även med ett reducerat fokus är det fortfarande ett flervariabelsproblem. I denna studie användes en metod för att hitta relationer mellan processparametrar och en Design Of Experiment-programvara, nämligen MODDE. Genom screening av processparametrar, inom programvaran, kan en statistisk utvärdering av operativt processfönster hittas med färre genomförda experiment. Utvecklingen av processparametrar kan traditionellt vara tidskrävande och resultera i ett onödigt stort antal experiment för att hitta det operativa fönstret av processparametrar. Experimentet visade att lasereffekt och punktavstånd påverkande den relativa densiteten mest, följt av exponeringstiden och spåravståndet. Experimentet genomfördes först med en lagertjocklek av 50 mikrometer, lagertjockleken resulterade i en relativ densitet på över 99,8 procent. Emellertid observerades stora fusionsdefekter inuti proverna. Även om en hög relativ densitet mättes, måste en poranalys genomföras för att fullt ut förstå storleken och formen på defekter eftersom de kan ha en avgörande inverkan på mekaniska egenskaperna. Det misstänktes att lagertjockleken var för hög och att defekterna kunde minskas genom att tillverka en ytterligare uppsättning av samma processparametrar men med en lägre lagertjocklek på 40 mikrometer istället. Minskningen av lagertjockleken resulterade i en signifikant minskning av de observerade defekterna. Framgent efter den här avhandlingen måste dock arbetet fortsätta att ytterligare optimera och öka soliditeten i det additivt tillverkade materialet. Det för att uppnå bättre prover och komma ännu närmre det konventionellt tillverkade materialets egenskaper.
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Ettaieb, Kamel. "Contribution à l'optimisation des stratégies de lagase en fabrication additive LPBF." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLN050.
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Au cours du procédé de fusion laser sur lit de poudre, la température atteinte dans une zone locale est susceptible de générer des gradients thermiques importants. Ces gradients conduisent à leur tour à l'apparition de contraintes résiduelles qui ont un effet sur les caractéristiques mécaniques de la pièce, provoquent des déformations, ainsi que des micro et macro fissures. Dans ce contexte, les trajectoires de lasage jouent un rôle fondamental sur le niveau et la distribution de la température au cours de la fabrication. Il est ainsi nécessaire de valider la génération des trajectoires au regard du comportement thermique induit par ce procédé.Cette thèse propose d'exploiter une méthode analytique pour développer un modèle qui permette d'analyser d'une manière rapide et efficace le comportement thermique dans la pièce lors de la fabrication. En effet, à partir d'une trajectoire de lasage donnée, d'un ensemble de paramètres liés au matériau de la pièce à fabriquer et de paramètres liés au procédé, l'outil développé effectue une simulation de la température en chaque point de la pièce, au cours de temps et de manière rapide, comparée aux autres logiciels de simulation thermique. En effet, afin de réduire le temps de calcul et l'espace mémoire utilisé pour une telle simulation, un ensemble de techniques d'optimisation a été mis en place.Le modèle proposé a été validé dans le cas de l'alliage Ti6Al4V par comparaison avec une simulation thermique par éléments finis obtenue par un logiciel industriel. Ensuite, les résultats de ce modèle sont confrontés aux résultats expérimentaux. Une fois le modèle validé, il a été mis en œuvre pour analyser des trajectoires couramment utilisées dans la littérature et dans l'industrie.Afin de réduire les gradients thermiques et améliorer la qualité des pièces, la solution proposée consiste à contrôler la température et la taille du bain de fusion. Pour se faire, le modèle thermique développé a été exploité pour moduler les paramètres du procédé au cours de la fabrication d'une part et pour développer une stratégie de lasage à pas adaptatif d'autre part<br>During manufacturing by Laser Powder Bed Fusion (LPBF), the achieved temperatures in local areas could generate significant thermal gradients. These gradients lead to the apparition of residual stresses which affect the mechanical characteristics of the part and may cause deformation, as well as micro and macro cracks. In this context, scanning paths play a fundamental role on temperature level and distribution during manufacturing. For that reason, it is necessary to validate the generation of trajectories considering the thermal behaviour induced by this process.The purpose of this PhD thesis is to use an analytical method in order to develop a model that allows a fast and efficient analysis of thermal behaviour, during part manufacturing. Indeed, with a given scanning path, material properties and process parameters, the developed tool performs a temperature simulation at each point of the part, over time and in a fast way, compared to other thermal simulation software. In order to reduce computation time and memory storage used for such a simulation, a set of optimization techniques has been proposed.The developed model has been validated in the case of the Ti6Al4V alloy through a comparison with a finite element thermal simulation obtained by industrial software. Then, the results of this model were compared to experimental results. Once validated, it has been implemented to analyze trajectories commonly used in the literature and industry.In order to reduce thermal gradients and improve part quality, the proposed solution consists in controlling the temperature and size of melt pool. For this purpose, the developed thermal model has been used to modulate the process parameters during manufacturing on the one hand and to develop an adaptive scanning strategy on the other hand
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Krishna, Jayanth. "Fatigue properties of Laser Powder Bed Fusion (LPBF) built 21-6-9 stainless stee." Thesis, Högskolan Väst, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:hv:diva-16788.
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Fatigue performance is one of the important mechanical properties which is hindering some of the additive manufacturing build structures. The main objective of this study is to investigate the fatigue life dependence of the 21-6-9 austenitic stainless-steel build using the laser powder bed fusion (LPBF) technique. The study is mainly focused on the fracture surface based on defects and the micro constituents, how they are related to the fatigue performance of the samples. 21 samples were build using optimized process parameters in which 9 of the samples were built-in vertical direction and the remaining 12 were built in the horizontal direction. Low cycle fatigue (LCF) testing was carried out with the samples with 2 conditions i.e., room temperature 24⁰C and 750 ⁰C. Before the specimens were subjected to testing the samples were stress relived at 600⁰C for 2 hours. Fractography was carried out on the fracture surface to pinpoint the initiation sites (concluded by analyzing the striations) and the cause of failure. Microstructural characterization was carried out in both the vertical and the horizontal direction of the build. The fatigue crack growth initiated from the surface where defects were present, when the cyclic loads were applied the stress concentration at these regions caused the crack initiation to take place. In some cases, the defect size was smaller at the initiation site, and that correlated to increased fatigue life. To optimize the fatigue life of LPBF built 21-6-9 is important to minimize the grain size. However, the absence of defects is crucial as well, as those typically are the weakest link. Therefore, minimizing those during the manufacturing is essential.
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Tonelli, Lavinia <1987>. "Additive Manufacturing by LPBF and WAAM of metals: correlation between production process, microstructure and mechanical properties." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2021. http://amsdottorato.unibo.it/9629/1/LaviniaTonelli_PhDThesis.pdf.
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In the most recent years, Additive Manufacturing (AM) has drawn the attention of both academic research and industry, as it might deeply change and improve several industrial sectors. From the material point of view, AM results in a peculiar microstructure that strictly depends on the conditions of the additive process and directly affects mechanical properties. The present PhD research project aimed at investigating the process-microstructure-properties relationship of additively manufactured metal components. Two technologies belonging to the AM family were considered: Laser-based Powder Bed Fusion (LPBF) and Wire-and-Arc Additive Manufacturing (WAAM). The experimental activity was carried out on different metals of industrial interest: a CoCrMo biomedical alloy and an AlSi7Mg0.6 alloy processed by LPBF, an AlMg4.5Mn alloy and an AISI 304L austenitic stainless steel processed by WAAM. In case of LPBF, great attention was paid to the influence that feedstock material and process parameters exert on hardness, morphological and microstructural features of the produced samples. The analyses, targeted at minimizing microstructural defects, lead to process optimization. For heat-treatable LPBF alloys, innovative post-process heat treatments, tailored on the peculiar hierarchical microstructure induced by LPBF, were developed and deeply investigated. Main mechanical properties of as-built and heat-treated alloys were assessed and they were well-correlated to the specific LPBF microstructure. Results showed that, if properly optimized, samples exhibit a good trade-off between strength and ductility yet in the as-built condition. However, tailored heat treatments succeeded in improving the overall performance of the LPBF alloys. Characterization of WAAM alloys, instead, evidenced the microstructural and mechanical anisotropy typical of AM metals. Experiments revealed also an outstanding anisotropy in the elastic modulus of the austenitic stainless-steel that, along with other mechanical properties, was explained on the basis of microstructural analyses.
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Masiagutova, Elina. "Étude de la génération des topographies de surfaces latérales issues du procédé LPBF pour un alliage d’aluminium AlSi10Mg." Thesis, Lyon, 2022. http://www.theses.fr/2022LYSEE002.
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Dans le cadre de ce travail, la génération des surfaces produites par le procédé de fusion laser sur lit de poudre LPBF a été étudiée. Le LPBF est un procédé de fabrication additive qui peut conduire à de nouvelles opportunités (fabrication de structures complexes avec canaux internes, structures lattices). Ce procédé attire donc une attention considérable en particulier dans l'industrie aéronautique. Une étude de l’influence des paramètres primaires du procédé LPBF sur la génération des surfaces a été réalisée. Au cours de cette étude, la relation entre la rugosité des surfaces supérieures et latérales et la densité du matériau a été établie. Cela a permis de déterminer la première fenêtre de paramètres optimaux.Une analyse de la dispersion de la rugosité et la reproductibilité du procédé ont ensuite été réalisées. Cette analyse a révélé une importante dispersion de la rugosité, notamment d'une face à l'autre. En conséquence, des recommandations sur les mesures de surface ont été proposées.L'effet de différents paramètres secondaires est également étudié afin de mieux comprendre la génération de la surface latérale et de l'optimiser. Cette étude a montré que les compensations et les réglages de contour sont des paramètres clés qui peuvent contribuent à la réduction de la rugosité des surfaces latérales. Sur la base des résultats de ces études, la rugosité a pu être diminuée d’un Sa de 40 µm à un Sa de 10 μm.Enfin, cette thèse présente une nouvelle approche de modélisation de génération des topographies des surfaces latérales. L’approche est basée sur la géométrie du cordon (rayons de courbure). Elle permet de prendre en compte la position des cordons et des couches et prédit la rugosité pour différentes stratégies de lasage et paramètres de compensation<br>In the current study, surface generation during additive manufacturing (AM), especially the laser powder bed fusion (LPBF) process was studied. LPBF is a progressive process that can lead to new opportunities, such as applications that require complex structures (internal channels or lightweight lattice structures). It has therefore attracted considerable attention, which has led to research and development in many industries, particularly in the aerospace industry.A surface generation study to optimize surface roughness and material density by examining the influence of the primary LPBF process parameters was therefore performed. During this study, the relationship between the roughness of the top and side surfaces and the density of the material was established. This made it possible to determine the first window of optimal parameters.An analysis of the roughness dispersion and process reproducibility were then carried out. This analysis revealed a significant roughness dispersion, especially from one side to the other. As a result, recommendations on surface measurements have been proposed.The effect of different process options (secondary parameters) are also studied in order to better understand the generation of the side surface and optimize it. This study showed that compensations and contour settings are key parameters that can help reduce the side surface roughness. Indeed, the geometric positioning of the different weld tracks is an important issue that must be addressed to reduce surface roughness. Based on the results of this study, it is possible to reduce the average surface roughness Sa from 40 to 10 μm.Finally, this thesis presents a new approach to modeling side surfaces roughness (at 0°). The approach is based on the weld track geometry (radii of curvature). It allows to take into account the weld tracks and layers position in relation to each other and thus to predict the roughness for different scanning strategies, compensation parameters
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De, sonis Edouard. "Evolution microstructurale de l'acier 316L élaboré par fabrication additive (LPBF et WAAM) et influence sur son comportement à rupture." Electronic Thesis or Diss., Université Paris sciences et lettres, 2024. http://www.theses.fr/2024UPSLM002.
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Ces travaux de thèse portent sur les relations microstructure - comportement à rupture d'aciers inoxydables austénitiques 316L élaborés par deux procédés de fabrication additive. Dans cette optique, plusieurs microstructures ont été élaborées par le procédé de fusion laser sur lit de poudre (Laser Powder Bed Fusion - LPBF) et le procédé arc-fil (Wire Arc Additive Manufacturing - WAAM). Différents traitements thermiques ont ensuite été appliqués aux échantillons consolidés, dans le but de faire évoluer leurs microstructures de manière contrôlée (détensionnement, homogénéisation, recristallisation). Une attention particulière a été portée aux cinétiques de recristallisation de ces aciers, très différentes de celles observées dans les aciers 316L conventionnels. Enfin, les matériaux ont été testés en résilience et/ou en ténacité.Dans le cas de l'acier 316L élaboré par procédé LPBF, l'étude comparative des mécanismes de déformation et de rupture a permis de déterminer l'influence des éléments de microstructure sur le comportement en résilience et en ténacité. Parmi ces éléments, les oxydes nanométriques présents dans ces matériaux en sortie de fabrication semblent avoir une influence significative sur les mécanismes de rupture, cette dernière intervenant par décohésion des interfaces oxyde / matrice. Après recristallisation, le mûrissement de ces oxydes aux joints des nouveaux grains recristallisés mène à une baisse significative de la résistance à l'amorçage et à la propagation de fissure. Des corrélations entre résilience et ténacité ont été établies. L'évolution de la résilience à basse température (jusqu'à - 193 °C) de différentes microstructures ont été comparées à celles d'aciers 316L forgés ou élaborés par compaction isostatique à chaud. Ces évolutions apparaissant similaires, il est conclu que les éléments de microstructure particuliers à l'acier 316L LPBF n'apparaissent pas avoir d'influence significative sur la sensibilité de sa résilience envers la température.Concernant l'acier 316L élaboré par procédé WAAM, un plan d'expérience plus restreint, établi sur la base des résultats obtenus après LPBF, a permis de déterminer l'influence des éléments de microstructure sur le comportement à rupture. Des mécanismes de rupture similaires à ceux des aciers 316L LPBF de l'étude ont été observés : rupture par décohésion des interfaces oxydes (ici de tailles submicrométriques) / matrice. A l'inverse, les traitements de recristallisation s'avèrent bénéfiques sur la résilience de cet acier, ceux-ci n'induisant pas la localisation des oxydes aux joints de grains. Enfin, la ferrite δ présente dans la microstructure de l'acier 316L WAAM brut de fabrication induit une rupture fragile du matériau à - 193 °C<br>This thesis investigates the relationships between the microstructure and fracture behavior of austenitic 316L stainless steels produced by two additive manufacturing processes. To this end, several microstructures were manufactured using the Laser Powder Bed Fusion (LPBF) and Wire Arc Additive Manufacturing (WAAM) processes. Various heat treatments were then applied to the consolidated samples, with the aim of developing their microstructures in a controlled manner (stress relieving, homogenization, recrystallization). A particular attention was paid to the recrystallization kinetics of these steels, which are very different from those observed in conventional 316L steels. Finally, the materials were tested for impact and/or fracture toughness.In the case of 316L steel produced using the LPBF process, a comparative study of deformation and fracture mechanisms enabled to determine the influence of microstructural features on the impact and fracture toughness behavior. Among these features, the nanometric oxides present in these materials at the end of the manufacturing process appeared to have a significant influence on fracture mechanisms, the latter occurring through decohesion at the oxide/matrix interfaces. After recrystallization, ripening of these oxides at recrystallized grain boundaries led to a significant drop in resistance to crack initiation and propagation. Correlations between impact toughness and fracture toughness have been established. The low-temperature impact toughness values (down to - 193°C) of various microstructures were compared with those of 316L steels either wrought or produced by hot isostatic pressing. As these trends appeared similar, it was concluded that the microstructural features specific to LPBF 316L steel did not have any significant influence on the sensitivity of its impact toughness to temperature.Regarding the WAAM-manufactured 316L steel, a more limited experimental campaign, based on the results obtained after LPBF, was used to determine the influence of microstructural features on the fracture behavior. Fracture mechanisms similar to those of LPBF 316L were observed: failure occurred by decohesion of the oxide (in this case submicrometer-sized) / matrix interfaces. Conversely, recrystallization treatments were beneficial to the impact toughness of this steel, as they did not induce the localization of oxides at grain boundaries. Lastly, the δ-ferrite present in the microstructure of as-built WAAM 316L induced brittle fracture of the material at - 193°C
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Holzer, Achill, Stephan Koß, Gunnar Matthiesen, et al. "Tribological investigations on additively manufactured surfaces using extreme high-speed laser material deposition (ehla) and laser powder bed fusion (LPBF)." Technische Universität Dresden, 2020. https://tud.qucosa.de/id/qucosa%3A71080.
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Today's economic and ecological directives demand for highly sustainable machine parts by low production cost and energy consumption. Consequently, it is crucial to guarantee a long service life by protecting all components against wear and corrosion. However, hydraulic components always include stressed surfaces, which suffer from heavy loads at high relative speeds. To prevent fretting, coating processes like thermal spraying or hard chrome have a long history in the field of hydraulics. New additive laser-based processes like EHLA and LPBF offer the potential to apply new coatings without environmentally hazardous substances such as chromium or to manufacture complex parts with new functionalities. So far, additively manufactured surfaces with relative movements are post-processed to obtain surface qualities similar to subtractive methods, as the tribological properties of additive surfaces have not been investigated to date. Therefore, this paper investigates the frictional behavior of 316L surfaces produced by laser-based EHLA and LPBF processes using a disc-disc tribometer.
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Somasundaram, Aruneshwar. "Characterization of Microstructure and Mechanical Properties of Laser Powder Bed Fusion Processed Inconel 625 Alloy." University of Cincinnati / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1627658971938259.
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Béal, Maxime. "Compréhension et maîtrise de la mise en œuvre par fabrication additive (LPBF) d'un alliage d'aluminium à basse teneur en silicium pour l'aéronautique." Electronic Thesis or Diss., Ecully, Ecole centrale de Lyon, 2022. http://www.theses.fr/2022ECDL0026.
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La fabrication additive devenant de plus en plus mature a montré sa capacité à être une technologie de rupture en matière d’innovation industrielle. En effet, la fabrication additive permet d’obtenir une pièce quasi fonctionnelle à partir d’un fichier 3D. La fusion laser sur lit de poudre (Laser Powder Bed Fusion - LPBF) est l’un des procédés de fabrication additive. La société Thales® est très fortement intéressée par ce type de procédé et souhaite le développement du LPBF pour accentuer sa compétitivité sur le marché aéronautique. Un alliage d’aluminium a été développé pour le procédé LPBF et breveté par Thales en 2019. Les travaux de thèse présentés dans ce manuscrit ont comme objectif de poursuivre les travaux menés sur cet alliage et de faciliter le processus d’industrialisation de celui-ci par le procédé LPBF pour des pièces destinées à l’aéronautique et l’aérospatiale. Le manuscrit est divisé en 4 parties, la première traitant de la bibliographie et des méthodes utilisées. La deuxième partie aborde l’interaction laser matière et l’optimisation de la rugosité. La partie numéro trois traite du cycle de vie de la poudre en analysant l’effet de la réutilisation et du stockage sur le procédé. Enfin la quatrième et dernière partie aborde l’optimisation de la composition chimique de l’alliage et la recherche d’un traitement thermique adapté. L’optimisation de l’interaction laser a montré la relation entre les paramètres utilisés et la géométrie des bains de fusion formés. Il a également été montré qu’il était plus difficile de mettre en oeuvre l’alliage 6061-Zr qu’un alliage d’aluminium de fonderie type Al-Si. Ce chapitre a également mis en lumière le phénomène de focal shift et l’importance de l’altitude plateau impactant fortement le procédé. Par la suite une optimisation de la rugosité a été effectuée en appliquant des contours. Un très bon état de surface est obtenu, néanmoins, cette méthode a été éprouvée sur des géométries plus complexes que des cubes et a montré ces faiblesses. Le traitement de la poudre a ensuite été abordé. La réutilisation de la poudre conduit à une hausse du taux d’oxygène et une modification chimique de la poudre. Le tamisage est essentiel pour garantir la granulométrie et éviter ces phénomènes. Le stockage des poudres est critique pour les applications visées. En effet, le stockage tel que réalisé dans cette étude a montré un fort impact sur le procédé réduisant la densité, l’allongement et la résilience des pièces tout en dégradant l’état de surface. Le brevet concernant le 6061-Zr étant assez large, le taux de Zirconium a été optimisé afin de répondre le plus possible au cahier des charges tout en évitant le phénomène de fissuration à chaud. Par la suite, des traitements thermiques ont été appliqués sur des alliages comportant différents taux de Zirconium afin d’observer l’impact de ces traitements en fonction de la température, de la durée et de la présence plus ou moins importante de Zirconium. L’ensemble de ces résultats a permis de lever des verrous scientifiques et facilite ainsi la progression de cette technologie vers une industrialisation maîtrisée pour des applications aéronautiques et spatiales<br>Additive manufacturing is becoming more and more mature and has shown its capacity to be a disruptive technology in terms of industrial innovation. Indeed, additive manufacturing allows to obtain a functional part from a 3D file. Laser Powder Bed Fusion (LPBF) is one of the additive manufacturing processes. Thales® is very interested in this type of process and would like to develop LPBF to increase its competitiveness in the aeronautical market. An aluminium alloy has been developed for the LPBF process and patented by Thales in 2019. The objective of the thesis work presented in this manuscript is to continue the work carried out on this alloy and to facilitate the industrialisation process of this alloy by the LPBF process for aeronautical and aerospace parts. The manuscript is divided into 4 parts, the first one focusing on the bibliography and the methods used. The second part deals with laser-material interaction and roughness optimisation. Part three deals with the life cycle of the powder by analysing the effect of reuse and storage on the process. Finally, the fourth and last part focuses on the optimisation of the chemical composition of the alloy and the search for a suitable heat treatment. The optimisation of the laser interaction showed the relationship between the parameters used and the geometry of the molten pool formed. It was also shown that it was harder to use the 6061-Zr alloy than a cast aluminium alloy such as Al-Si alloy. This chapter also highlighted the focal shift phenomenon and the importance of the plate altitude which has a strong impact on the process. Subsequently, a roughness optimisation was carried out by applying contours. A very good surface finish was obtained, however, this method was tested on more complex geometries than cubes and showed its weaknesses. The life cycle of the powder was then discussed. The reuse of the powder leads to an increase in oxygen content and chemical modification of the powder. Sieving is essential to ensure particle size and avoid these phenomena. The storage of powders is critical for the intended applications. Indeed, storage as carried out in this study has shown a strong impact on the process reducing the density, elongation and resilience of the parts while degrading the surface finish. As the patent for 6061-Zr is quite broad, the zirconium content was optimised to meet the specifications as much as possible while avoiding hot cracking. Subsequently, heat treatments were applied to alloys with different levels of Zirconium in order to observe the impact of these treatments as a function of temperature, duration and the level of Zirconium content. All of these results helped to remove scientific obstacles and thus facilitate the progression of this technology into controlled industrialisation for aeronautical and space applications
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Veneziano, Giovanni. "Studio del comportamento tribologico della lega AlSi10Mg prodotta mediante Laser Powder Bed Fusion in diverse condizioni di trattamento termico e superficiale." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2022.
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La lega AlSi10Mg è la lega Al attualmente più indagata per la realizzazione di componenti mediante tecnologia Laser-based Powder Bed Fusion (LPBF). Nonostante l’elevata resistenza specifica dovuta alla sua peculiare microstruttura, la lega LPBF AlSi10Mg presenta ridotte proprietà tribologiche, che possono risultare un fattore limitante ad un suo più ampio impiego in numerosi settori industriali. Il presente lavoro di tesi ha quindi come obiettivo la caratterizzazione tribologica della lega LPBF AlSi10Mg sottoposta a trattamenti termici e di modifica superficiale. Nel dettaglio, sono stati analizzati gli effetti sulle proprietà tribologiche della lega di tre diversi trattamenti termici: T5 (invecchiamento artificiale a 160°C x 4h), T6 benchmark (solubilizzazione a 540°C x 1h e invecchiamento a 160°C x 4h) e T6 a rapida solubilizzazione (solubilizzazione a 510°C x 1h e invecchiamento a 160°C x 6h). Lo studio ha permesso di evidenziare come l’evoluzione microstrutturale indotta dai trattamenti termici abbia avuto effetti negativi sulla resistenza ad usura del materiale, mentre non sono stati rilevati effetti significativi in termini di coefficiente d’attrito. È stato poi valutato il comportamento tribologico della lega rivestita Ni-P e Ni-P + DLC. L’obiettivo di questa fase è stato quello di individuare un ottimale ciclo di deposizione tale da garantire: (i) l’integrazione di un eventuale trattamento termico nella sequenza di rivestimento; (ii) l’ottimizzazione del comportamento tribologico del componente. I rivestimenti Ni-P hanno permesso di ottenere ottima resistenza ad usura, ma un aumento significativo del coefficiente d’attrito. L’impiego del DLC come topcoating invece ha permesso di abbinare un’eccellente resistenza ad usura ad un ridotto coefficiente d’attrito. L’integrazione della sequenza del trattamento termico T5 e T6R nella sequenza di rivestimento Ni-P + DLC non ha portato a criticità operative, evidenziando l’applicabilità di cicli tecnologici combinati.
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Bravin, Marco. "Studio ed ottimizzazione del processo di fabbricazione additiva LPBF per la laga AlSi10Mg, simulazione di processo, ottimizzazione topologica piastre sterzo Ducati e produzione." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2021.
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L'additive manufacturing è una tecnologia che permette di realizzare un oggetto strato dopo strato a partire da un modello 3D digitale. Svariati sono i settori dove la stampa 3D trova applicazione, tra cui si colloca il settore dell'automotive. Per ottenere veicoli con performance migliori, è necessario infatti che le loro componenti siano ottimizzate e più leggere possibili; l'utilizzo di processi produttivi additivi consente di raggiungere questo obiettivo, garantendo una maggiore flessibilità durante le fasi di design e produzione dell'oggetto. In questo contesto si inserisce il presente elaborato, frutto dell’attività di tirocinio svolta presso il Laboratorio del dipartimento di Ingegneria Meccanica dell’Università di Bologna, in collaborazione con Ducati Motor Holding. L’obiettivo della tesi è stato quello di fornire all’azienda le linee guida per approcciarsi alla tecnologia, sfruttando un caso di studio di re-ingegnerizzazione delle piastre sterzo del modello di motoveicolo Ducati Panigale, utilizzando il processo di manifattura additiva denominato "Laser Powder Bed Fusion" (LPBF). Nella prima parte, è stato definito il miglior set di parametri di processo, adottando quattro piani sperimentali volti ad investigare e rispettivamente minimizzare le difettologie, massimizzare i sottosquadri realizzabili, produrre componenti con pareti sottili e minimizzare la rugosità superficiale. In seguito, sono state ottimizzate topologicamente le piastre sterzo utilizzando il software Inspire di Altair, simulando poi il processo produttivo tramite Simufact Additive. Infine, sono state realizzate le prime
stampe. I risultati ottenuti hanno dimostrato come la metodologia sviluppata permetta di ottenere piastre più leggere (9-13%), non compromettendo la resistenza di queste ultime e garantendo un risparmio di peso di 160g. L'aggiunta di ulteriori accortezze sul processo di stampa e la misurazione reale delle deformazioni consentirà di ottenere pezzi con prestazioni migliori.
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Mishurova, Tatiana [Verfasser], Guillermo Carlos [Akademischer Betreuer] Requena, Sandra [Akademischer Betreuer] Korte-Kerzel, and Giovanni [Akademischer Betreuer] Bruno. "Influence of residual stress and microstructure on mechanical performance of LPBF TI-6AL-4V / Tatiana Mishurova ; Guillermo Carlos Requena, Sandra Korte-Kerzel, Giovanni Bruno." Aachen : Universitätsbibliothek der RWTH Aachen, 2020. http://d-nb.info/1231542160/34.
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Hasting, William. "Geometric Effects of Free-Floating Technique on Alloy 718 Parts Produced via Laser-Powder Bed Fusion." University of Cincinnati / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1613751580039925.
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Tissot, Nicolas. "Amélioration du procédé LBM par nanostructuration de poudres d’aluminium." Thesis, Lyon, 2019. http://www.theses.fr/2019LYSEE001.
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Le procédé de fabrication additive par fusion laser sur lit de poudre (LBM) propose de nombreux avantages pour beaucoup de secteurs industriels par rapport à d’autres procédés conventionnels : formes complexes, allégement structural, temps de fabrication plus rapide, etc. Contrairement à de nombreux alliages déjà qualifiés industriellement, les alliages d’aluminium demeurent encore pénalisés lors de la mise en oeuvre avec ce procédé : réflectivité optique élevée, conductivité thermique importante, phénomène de fissuration ou encore porosité liée à la présence d’alumine non fondue. Les travaux réalisés au cours de cette thèse se sont portés sur l’amélioration des propriétés optiques des poudres d’aluminium par une approche de nanostructuration de la surface des particules. Pour cela, deux voies de fonctionnalisation des poudres ont été étudiées. La première s’est portée sur la réalisation de revêtements uniformes de silicium créant alors des phénomènes interférentiels et permettant de maximiser l’absorption optique à une longueur d’onde précise qui correspond à celle des lasers utilisés en LBM (1 064 nm). Les travaux basés sur un modèle utilisant la théorie de Mie ont permis d’identifier l’intérêt de déposer un revêtement de silicium de 215 nm augmentant ainsi l’absorbance d’une particule d’aluminium de 4 % à 25 %. La seconde solution étudiée est l’augmentation de la rugosité de la poudre d’aluminium par un dépôt en surface de particules nanométriques. Ce procédé a été réalisé par réduction chimique en voie liquide pour déposer du cuivre. L’objectif ici, en plus d’une augmentation de l’absorption optique, est la formation in situ d’un alliage Al–Cu lors du procédé de fusion laser. Après dépôt de cuivre, l’absorption optique de la poudre à 1 064 nm est améliorée de 70 %. Pour terminer, des essais de fusion laser de la poudre d’AlSi12 revêtue de 4 % massique de cuivre ont été réalisés pour étudier l’impact du revêtement sur la densité d’énergie permettant de fabriquer une pièce dense. Il a été constaté une diminution notable de cette densité en comparaison de celle d’autres alliages Al–Cu de la littérature, sans toutefois pouvoir attribuer ce résultat à la seule amélioration de l’absorption optique de la poudre dans la mesure où les alliages sont de stoechiométrie légèrement différente<br>Laser powder bed fusion process (LPBF) offers many advantages for industrials compared to conventional processes: complex shapes, structural lightening, faster prototyping, etc. Unlike other metals already industrially qualified, aluminium alloys still face several difficulties with this process: high optical reflectivity, significant thermical conductivity, crack phenomenon or porosity due to the presence of unmelted alumina. Studies carried out during the thesis focused on improving optical properties of aluminium powders. For this purpose, two strategies were studied. The first is the development of a silicon coating in order to create interferential phenomena to maximize the optical absorption for a specific wavelength (1 064 nm). Model-based work using Mie theory has identified the interest in deposing a silicon coating of 215 nm on the surface of aluminium particles reducing the reflectivity from 96 % to 75 %. The second strategy is the increase of the roughness of aluminium powder with nanoparticles deposit on the surface. The process used is electroless to deposit copper on the powder. The objective here, in addition to a better optical absorption, is the in situ formation of a new Al–Cu alloy during the process. After copper deposition (4 %wt), the absorption of the powder at 1 064 nm is improved by 70 %. Finally, laser melting tests of the AlSi12 powder coated by 4 %wt of copper were performed to evaluate the impact of the coating on the energy density to print dense parts. Results showed a reduction of the necessary energy density with respect to literature data for other Al-Cu alloys. However, due to differences in stoechiometry, such an improvement cannot be unambiguously assigned to a better optical absorption
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PARIZIA, SIMONE. "Study of heat treatments for the Inconel 625 and process optimization for the Inconel 939 produced by Laser Powder Bed Fusion." Doctoral thesis, Politecnico di Torino, 2020. http://hdl.handle.net/11583/2827708.
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Matthiesen, Gunnar, Daniel Merget, Tobias Pietrzyk, Stephan Ziegler, Johannes Henrich Schleifenbaum, and Katharina Schmitz. "Design and experimental investigation of an additive manufactured compact drive." Technische Universität Dresden, 2020. https://tud.qucosa.de/id/qucosa%3A71082.
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In recent years, additive manufacturing (AM) has become one of the most revolutionary and promising technologies in manufacturing. The process of making a product layer by layer is also often referred to as 3D printing. Once employed purely for prototyping, AM is now increasingly used for small series production, for example in aerospace applications. The paper starts with a motivation for AM in hydraulic applications and the development of an AM internal gear pump. For a better understanding of the manufacturing process, a brief introduction to AM highlighting the advantages and challenges is given. The AM internal gear pump is part of an electrohydraulic power pack, which is used to power an electrohydraulic actuator (EHA). The power pack contains all necessary peripherals to realise the hydraulic system of the EHA. The AM process allows for new design possibilities, but the process differs strongly compared to subtractive manufacturing processes and therefore is outlined here. The paper concludes by presenting measurement results of the AM internal gear pump.
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PAKKANEN, JUKKA ANTERO. "Designing for Additive Manufacturing - Product and Process Driven Design for Metals and Polymers." Doctoral thesis, Politecnico di Torino, 2018. http://hdl.handle.net/11583/2714732.
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Additive Manufacturing (AM) has broken through to common awareness and to
wider industrial utilization in the past decade. The advance of this young
technology is still rapid. In spoken language additive manufacturing is referred as
3D printing for plastic material and additive manufacturing is left as an umbrella
term for other materials i.e. metallic materials and ceramics. As the utilization of
AM becomes more widespread, the design for additive manufacturing becomes
more crucial as well as its standardization.
Additive manufacturing provides new set of rules with different design
freedom in comparison with subtractive manufacturing methods. This is thought
to empower product driven designs. However, in the AM methods there are
process driven variables that limit the designs functions to what could be
manufactured. There are often extra steps after production to finalize the design.
Topology optimization utilizes product driven design where material is only
where it is needed to be. The design is computed without taking into account any
manufacturing constrains and only the design in the final application stage is
achieved. Topology optimization algorithm is explored in detail for two
algorithms. Then these algorithms are compared in case study I to gain better
understanding of the algorithms functions. Case study I consists of 2D and 3D
algorithms where a 3D level set method algorithm was written for this purpose.
The concept of designing for additive manufacturing is examined for
polymeric materials in case study II with a help of topology optimization design
software tailored for additive manufacturing market. The parts are manufactured
with different AM methods, examined and results are explained. The results show
an interesting effect of anisotropy and the manufacture methods effect in the part
mechanical properties.
On the other hand, process driven design and its concepts important as the
manufacturing method dictates, what can and should be done economically. Metal
AM process constraints are explored in case study III through accuracy studies in
metal additive manufacturing at laser powder bed fusion (LPBF) technology.
Accuracy and surface studies are concluded to gain a better understanding of the
process and manufacturability of metal parts. The gain knowledge is explaned and
examples are shown how these are utilized to make metal parts with tailored
properties and with minimal post processing needs.
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Pelouard, Vanina. "Analyse de l'impact de la microstructure d'un alliage 718 obtenue par fabrication additive (LPBF) vis à vis de la résistance à la corrosion sous contrainte en milieu primaire de REP : étude des effets d'échelles." Electronic Thesis or Diss., Université de Toulouse (2023-....), 2024. http://www.theses.fr/2024TLSEP044.
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Les perspectives d’application de la FAM (Fabrication Additive Métallique) n’échappent pas au domaine du nucléaire où l’utilisation du procédé LPBF (fusion laser sur lit de poudre) ouvre la voie à de potentielles évolutions technologiques, notamment dans le domaine de la conception et de la fabrication d’assemblages de combustibles nucléaire. Dans ce domaine, l’utilisation du 718-LPBF pourrait permettre d’atteindre des performances améliorées et augmenter les marges de fonctionnement de certains composants critiques. Toutefois, ce procédé engendre des microstructures qui se distinguent significativement de celles issues des gammes de fabrication conventionnelles et se heurte à la capacité à justifier les performances des matériaux qui en résultent lors d’exposition à des modes de chargement couplant à la fois une sollicitation mécanique, l’irradiation et une composante environnementale par exemple de type corrosion en milieu REP, tel que rencontrés dans les assemblages combustibles. Lors de ce type de chargement, et selon la microstructure utilisée, un mécanisme d’endommagement de type corrosion sous contrainte (CSC) peut se développer et mener à une ruine prématurée du composant. Cette étude multi-échelle, lancée par Framatome, a ainsi permis d’identifier les fenêtres microstructurales permettant de diminuer, voire inhiber, la sensibilité à la CSC de l’alliage 718 LPBF, tout en gardant de hautes performances mécaniques comparables au 718 conventionnel. Un mécanisme d’endommagement en CSC basé sur l’effet cumulé de la diffusion de l’oxygène aux joints de grains via la formation de NiO et de la localisation de la déformation dans la sous-structure dendritique, a été identifié. Ainsi, une optimisation de la microstructure a été mise en œuvre via des traitements post fabrication qui limitent la localisation de la déformation ainsi que la contribution néfaste du glissement intergranulaire. Ces états microstructuraux confèrent une bonne résistance à la CSC à l’alliage 718 LPBF. Les différents résultats obtenus constituent de plus une première contribution à la compréhension du mécanisme de CSC en milieu REP du 718 LPBF qui n’a pas été jusqu’alors rapportée dans la littérature. Les résultats des essais, les analyses et observations réalisées, précisent les lignes directrices permettant la mise en œuvre de microstructures adaptées aux applications visées. De plus les résultats obtenus révèlent les opportunités offertes par l’utilisation de ce nouveau mode de fabrication pour des applications nucléaires<br>The opportunities for applications of metal additive manufacturing (MAM) do not exclude the nuclear field, where the use of the LPBF process (laser melting on a powder bed) opens the way to potential technological developments, particularly in the design and manufacture of nuclear fuel assemblies for pressurized water reactors. In this field, the use of 718-LPBF could lead to improved performance and increased operating margins for critical parts. However, this process generates microstructures that differ significantly from those produced by conventional manufacturing processes, and raises the question of how to justify the performance of the resulting materials. This question is particularly relevant when the alloy is exposed to loading conditions that combine both a mechanical stress, irradiation and an environmental condition, as encountered in fuel assemblies. Under this type of loading, and depending on the microstructure used, a stress corrosion cracking (SCC) damage mechanism can develop, leading to premature component failure. This multi-scale study, launched by Framatome, has enabled to define a microstructural window that reduces or even inhibit the susceptibility of alloy 718 LPBF to SCC, while maintaining high mechanical performances fully comparable to those of conventional 718. A SCC damage mechanism based on the cumulative effect of oxygen diffusion at grain boundaries via NiO formation and strain localization in the dendritic substructure has been identified. Microstructure optimization was therefore implemented via post-fabrication treatments that limit the localization of deformation as well as the detrimental contribution of intergranular slip. These microstructural conditions give alloy 718 LPBF good resistance to CSC. These results also constitute a first contribution to the understanding of the SCC mechanism of the 718 LPBF in a PWR environment, which has not yet been reported in the literature. The results of the tests, the analyses and the observations made, clarify the guidelines for the implementation of microstructures adapted to the targeted applications. These results also reveal the relevance of this new process mode for nuclear applications and open new opportunities for futur implementation
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VIRGILLITO, ENRICO. "Metallic powders production via Gas Atomization: Material development for Laser Powder Bed Fusion processing." Doctoral thesis, Politecnico di Torino, 2022. http://hdl.handle.net/11583/2971110.
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Davis, Taylor Matthew. "Feasibility and Impact of Liquid/Liquid-encased Dopants as Method of Composition Control in Laser Powder Bed Fusion." BYU ScholarsArchive, 2021. https://scholarsarchive.byu.edu/etd/9256.
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Additive manufacturing (AM) – and laser powder bed fusion (LPBF) specifically – constructs geometry that would not be possible using standard manufacturing techniques. This geometric versatility allows integration of multiple components into a single part. While this practice can reduce weight and part count, there are also serious drawbacks. One is that the LPBF process can only build parts with a single material. This limitation generally results in over-designing some areas of the part to compensate for the compromise in material choice. Over-designing can lead to decreased functional efficiency, increased weight, etc. in LPBF parts. Methods to control the material composition spatially throughout a build would allow designers to experience the full benefits of functionality integration. Spatial composition control has been performed successfully in other AM processes – like directed energy deposition and material jetting – however, these processes are limited compared to LPBF in terms of material properties and can have inferior spatial resolution. This capability applied to the LPBF process would extend manufacturing abilities beyond what any of these AM processes can currently produce. A novel concept for spatial composition control – currently under development at Brigham Young University – utilizes liquid or liquid-encased dopants to selectively alter the composition of the powder bed, which is then fused with the substrate to form a solid part. This work is focused on evaluating the feasibility and usefulness of this novel composition control process. To do this, the present work evaluates two deposition methods that could be used; explores and maps the laser parameter process space for zirconia-doped SS 316L; and investigates the incorporation of zirconia dopant into SS 316L melt pools. In evaluating deposition methods, inkjet printing is recommended to be implemented as it performs better than direct write material extrusion in every assessed category. For the process space, the range of input parameters over which balling occurred expanded dramatically with the addition of zirconia dopant and shifted with changes in dopant input quantities. This suggests the need for composition-dependent adjustments to processing parameters in order to obtain desired properties in fused parts. Substantial amounts of dopant material were confirmed to be incorporated into the laser-fused melt tracks. Individual inclusions of 100 $nm$ particles distributed throughout the melt pool in SEM images. Howewver, EDX data shows that the majority of the incorporated dopant material is located around the edges of the melt pools. Variations of dopant deposition, drying, and laser scanning parameters should be studied to improve the resulting dopant incorporation and dispersion in single-track line scans. Area scans and multi-layer builds should also be performed to evaluate their effect on dopant content and dispersion in the fused region.
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LINS, Thiago Ubiratan Lins e. "Avaliação do efeito anticâncer dos derivados tiazacridínicos LPSF/AC-34 e LPSF/AC-129." Universidade Federal de Pernambuco, 2014. https://repositorio.ufpe.br/handle/123456789/17075.
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Previous issue date: 2014-01-23<br>FACEPE<br>Os derivados tiazacridínicos (Z/E)-5-(acridin-9-il) metileno-3-(3-cloro-benzil)-tiazolidin-2,4-diona (LPSF/AC-34) e (Z)-5-(acridin-9-il) metileno-3-(3-cloro-benzil)-4-tioxo-tiazolidin-2-ona (LPSF/AC-129) foram sintetizados. O produto da reação continha 72% do derivado (Z) LPSF/AC-129 e 22% do derivado (Z/E) LPSF/AC-34, com rendimento de 94%. As estruturas químicas dos derivados foram determinadas por espectroscopia no infravermelho, espectroscopia de ressonância magnética nuclear de hidrogênio e espectrometria de massas e a pureza por HPLC-MS. A citotoxicidade da mistura LPSF/AC-34 + LPSF/AC-129 foi avaliada frente a linhagens de células tumorais aderentes e não-aderentes pelo método de MTT. Os valores obtidos para o IC50 foi de 3,98 μM (linfoma de Burkitt - RAJI); 35,6 μM (leucemia de células T - Jurkat); 8,05 μM (leucemia promielocítica aguda - HL-60); 14,27 μM (leucemia linfoblástica aguda - CCRF-CEM); 55,77 μM (glioblastoma - NG97); >100 μM (mama - T47D). A seletividade dos compostos foi avaliada em células mononucleadas do sangue periférico (PBMC) de voluntários sadios e apresentou uma IC50>100μM. Em seguida, avaliou-se por citometria de fluxo o efeito dos derivados no ciclo celular e indução de morte. Observou-se que a mistura LPSF/AC-34 + LPSF/AC-129 na dose de 3,98 μM não causou alterações significativas no ciclo celular e induziu a morte por apoptose na linhagem de linfoma RAJI. Em paralelo, avaliou-se por RT-PCR o efeito dos derivados na expressão dos genes GADD153, PPARγ, Bcl-2, SOD1, Beclin, Bid, p21 e RIP3 nas linhagens HL-60 e CCRF-CEM em comparação às células não tratadas. Após 10 horas de exposição da linhagem HL-60 aos derivados, na dose de 8,05 μM (n=3), observou-se a modulação dos genes GADD153 (12,47 vezes, p=0,0808) e PPARγ (4,82 vezes, p=0,2277). Na linhagem CCRF-CEM (dose de 14,27 μM; n=3) observou-se a modulação dos genes Bcl-2 (0,97 vezes, p=0,4409), Bid (1,62 vezes, p=0,3911), RIP3 (0,97 vezes, p=0,3722) e SOD1 (1,29 vezes, p=0,0172) indicando interferência no estresse oxidativo. Avaliou-se também o efeito dos derivados na expressão protéica de NFkB, Bax, pPTEN e GADD153 por Western Blotting. Observou-se na linhagem HL-60 a modulação de NFkB (p=0,3012; n=3) e de Bax (p=0,9221; n=3). Na linhagem CCRF-CEM observou-se o aumento de NFkB (p=0,0053; n=3) e Bax (p=0,6956; n=3). Os resultados mostraram que os derivados LPSF/AC-34 + LPSF/AC-129 apresentam atividade frente às linhagens de tumores hematopoiéticos e sólidos, modulando expressão gênica e proteica.<br>The (Z / E) -5- (acridin-9-yl) methylene-3- (3-chloro-benzyl) thiazolidin-2,4-dione (LPSF / AC-34) and (Z) -5 - (acridin-9-yl) methylene-3- (3-chloro-benzyl) -4-thioxo-thiazolidin-2-one (LPSF / AC-129) thiazacridinic derivatives were synthesized. The reaction product contained (Z) LPSF / AC-129 (72%) and (Z / E) LPSF / AC-34 (22%), with 94% of yield. The derivatives chemical structures were determined by infrared spectroscopy, nuclear magnetic resonance spectroscopy and mass spectrometry hydrogen and the purity was determined by HPLC-MS. The mixture LPSF / AC-34 + LPSF / AC-129 cytotoxicity was evaluated against adherent and non-adherent tumor cell lines throught MTT method. The IC50 values obtained was 3,98 μM (Burkitt lymphoma - RAJI); 35,6 μM (T-cell leukemia - Jurkat); 8,05 μM (acute promyelocytic leukemia - HL-60); 14,27 μM (acute lymphoblastic leukemia - CCRF-CEM); 55,77 μM (glioblastoma - NG97); > 100 μM (breast - T47D). The compounds selectivity was assessed in peripheral blood mononuclear cells (PBMC) of healthy volunteers and showed an IC50> 100μM. Then, the derivative effect on cell cycle and induction of death was assayed by flow cytometry. It was observed that the 3,98 μM dose of mixture LPSF / AC-34 + LPSF / AC-129 caused no significant changes in cell cycle and induce death by apoptosis in lymphoma cell line RAJI. In parallel through RT-PCR, it was evaluated the derivatives effect on GADD153, PPAR gamma, Bcl-2, SOD1, Beclin, Bid, RIP3, p21 genes expression in HL-60 and CCRF-CEM tumor cell lines compared to untreated cells . After submitting HL-60 line to 10 hours exposure of 8.05 μM derivatives dose (n = 3), we observed the modulation of GADD153 (12,47 fold, p=0.0808) and PPAR gamma (4,82 fold, p=0.2277) genes. On CCRF-CEM cell line (14,27 μM dose; n=3) it was observed modulation of Bcl-2 (0,97 fold, p = 0,4409), Bid (1,62 fold, p = 0,3911), RIP3 (0,97 fold, p=0,3722) and SOD1 (1,29 fold, p=0,0172) genes indicating interference on oxidative stress. It is also evaluated the derivatives effect on protein expression of NFkB, Bax, GADD153 and pPTEN by Western blotting. It was observed, in HL-60 cell line, the NFkB (p=0,3012; n=3) and Bax (p=0,9221; n=3) modulation. In CCRF-CEM cell line was observed NFkB (p=0,0053; n=3) and Bax (p=0.6956; n=3) increase. The results showed that the derivatives LPSF / AC-34 + LPSF / AC-129 had activity against hematopoietic and solid tumor cell lines by modulating gene and protein expression.
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CANDELIER, LAURENT. "Isolement et caracterisation des particules lipoproteiques plasmatiques lpb, lpb : e, lpb c-iii et lpb : c-iii : e. mise au point et utilisation d'une methode de chromatographie d'immunoaffinite sequentielle." Lille 2, 1989. http://www.theses.fr/1989LIL2P259.
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Clark, Jared A. "The Effects of Build Orientation on Residual Stresses in AlSi10Mg Laser Powder Bed Fusion Parts." Youngstown State University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=ysu1578819644598848.
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Borsari, Mattia. "Studio di strutture reticolari metalliche stampate con tecnologia additiva a letto di polvere e analisi del comportamento a fatica tramite DIC (Digital Image Correlation)." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2020.
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Questo elaborato offre uno spunto sullo stato dell’arte della tecnologia SLM (Selective Laser Melting) con particolare attenzione all’influenza dei parametri di processo sulla qualità del prodotto finale; propone svariati esempi di prove meccaniche quasi statiche e di fatica eseguite sulle celle più comuni in letteratura, sottolineando la varietà dei difetti legati al meccanismo di fusione e alla scelta di parametri di stampa non ottimizzati; mette in luce l’importanza della DIC (Digital Image Correlation) per la comprensione della dinamica eterogenea del comportamento delle strutture reticolari.
A questa prima parte si aggiunge una campagna sperimentale svolta su provini in CoCrMo, nelle condizioni as build e dopo un trattamento termico, dedicata allo studio delle prestazioni a fatica in condizioni compression-compression per la costruzione della curva di Wöhler. Tutte le prove sono monitorate registrando sequenze di foto per ciascun campione in momenti diversi del test e destinate all’analisi DIC mediante il software GOMcorrelate®.
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ANDRADE, Fabrício Havy Dantas de. "Estudos de caracterização de um novo agente esquistossomicida e tripanossomicida (LPSF/GQ-238)." Universidade Federal de Pernambuco, 2016. https://repositorio.ufpe.br/handle/123456789/18628.
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Previous issue date: 2016-02-16<br>FACEPE<br>CAPES<br>O 3-(2,6-diflúor-benzil)-5-(5-bromo-1H-indol-3-ilmetileno)-tiazolidina-2,4-diona
(LPSF/GQ-238) é um análogo indólico-tiazolidínico, apresenta potencial atividade
esquistossomicida e tripanossomicida. Poucos relatos na literatura mostram a
eficácia de uma substância contra a esquistossomose e a doença de chagas. Estas
doenças são consideradas doenças debilitantes e afeta milhões de pessoas no
mundo. Assim, o objetivo deste trabalho foi realizar a caracterização físico-química
do LPSF/GQ-238 visando conhecer suas propriedades químicas e físicas para
desenvolvimento de uma nova alternativa de tratamento para as doenças
supracitadas. O estudo abrangeu a caracterização físico-química, estabilidade
térmica e compatibilidade fármaco-excipiente por técnicas espectroscópicas (IV,
RMN), termoanalíticas (DSC, DSC-fotovisual, TG e Pyr-CG/EM), validação do
método analítico, bem como DRX e MEV. Os resultados obtidos da avaliação físicoquímica
do LPSF/GQ-238 frente a diferentes técnicas permitiram caracterizá-lo do
ponto de vista físico, químico e morfológico. O protótipo apresentou-se com 99,5%
de pureza, funde a 272,48 ± 0,28 °C e entalpia de 78,31 ± 4,31 J.g-1 com pico
endotérmico de fusão característico de uma forma cristalina que foi corroborado pela
DRX, com habito cristalino do tipo agulha por MEV, apresenta baixa solubilidade
aquosa e cinética de decomposição de ordem zero. O estudo de compatibilidade
evidenciou possíveis incompatibilidades químicas e/ou físicas entre o LPSF/GQ-238
e os excipientes estudados. Concluí-se que a caracterização da NEQ obteve
resultados sólidos sobre o comportamento físico e químicos de um protótipo
antiparasitário para tratar a esquistossomose e a doença de chagas.<br>The 3-(2,6-difluoro-benzyl)-5-(5-bromo-1H-indol-3-ylmethylene)thiazolidine-2,4-dione
(LPSF/GQ-238) is an indole-thiazolidine analogue with schistosomicidal and
trypanocidal potential activity. Few reports in the literature show the effectiveness of
a substance against schistosomiasis and Chagas disease simultaneously. These are
considered debilitating diseases affecting millions of people worldwide. The objective
of this study was to perform the physicochemical characterization of LPSF/QA-238
aiming to know their chemical and physical properties for the development of a new
alternative treatment for the above diseases. The study covered the physicochemical
characterization, thermal stability, and drug-excipient compatibility by spectroscopic
techniques (IR, NMR), thermoanalytical (DSC, DSC-fotovisual, TG and Pyr-GC/MS),
validation of analytical method, as also, XRD and SEM .The results of
physicochemical evaluation of LPSF/QA-238 compared to different techniques
allowed characterize it physical, chemical and morphologically. The prototype
presented 99.5% purity, melting at 272.48 ± 0.28 °C and enthalpy of 78.31 ± 4.31 Jg1
, endothermic peak of melting characteristic of a crystalline form which was
confirmed by XRD, with crystalline habit needle type observed in the SEM, has low
aqueous solubility and kinetics of order decomposition zero.The compatibility study
highlighted possible chemical and / or physical incompatibilities between LPSF / QA238
and the excipients studied.It is concluded that the new chemical entity
characterization obtained actual results about the physical and chemical behavior of
a prototype antiparasitic to treat schistosomiasis and Chagas disease.
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Karlsson, Anders. "Sociala kunskaps- och lärandebegrepp hos Jean-Jacques Rousseau och Lpf 94." Thesis, Malmö högskola, Lärarutbildningen (LUT), 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:mau:diva-33989.
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Arbetets syfte är att fördjupa förståelsen för vad ett socialt kunskaps- och lärandebegrepp är och vilka konsekvenser det kan få för utformningen av undervisningen. Arbetet utgår ifrån Johan Asplunds begrepp om social responsivitet och dess betydelse för en social förståelse av kunskap och lärande. Det sker genom kvalitativa textanalyser av Jean Jacques Rousseaus bildningsroman Emile (1762)och Lpf 94. Översiktligt anger resultatet vilket utrymme elevens sociala responsivitet ges genom den förmedlade förståelsen av kunskaps- och lärandebegreppen. Lpf 94 utvecklar en bildningsorienterad och konstruktivistisk syn på begreppen. Rousseaus pedagogik är praktisk och handlingsinriktad där ramstyrningen anges av Emiles kunskapsutveckling.
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de, Siqueira Ferraz Rafaela. "Validação de método espectrofotométrico UV para determinação do derivado acridínico LPSF/AC-04 em lipossomas." Universidade Federal de Pernambuco, 2011. https://repositorio.ufpe.br/handle/123456789/1687.
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Previous issue date: 2011<br>Coordenação de Aperfeiçoamento de Pessoal de Nível Superior<br>Os derivados acridínicos têm despertado a atenção de vários pesquisadores por
apresentarem um amplo espectro de atividades biológicas, como atividade
antibacteriana, antimalárica, antitripanossômica, leishmanicida, antiviral e mais
recentemente por sua atividade antitumoral. O LPSF/AC-04 é um derivado
tiazacridínico e caracteriza-se por ser um pó amorfo, amarelo-esverdeado, de peso
molecular 410 g/mol, com ponto de fusão igual a 199°C e uma baixa solubilidade em
água, característica essa que dificulta sua utilização terapêutica. Sendo assim, a
incorporação deste fármaco em sistemas de liberação controlada, tais como, os
lipossomas, torna-se uma alternativa viável para sua utilização. O controle de qualidade
de fármacos puros e em formas farmacêuticas é realizado por métodos oficiais ou
validado. A espectrofotometria é uma técnica analítica bastante conveniente, muito
utilizada em laboratórios de controle de qualidade, devido à sua simplicidade, baixo
custo e larga disponibilidade. Assim, o presente estudo visou o desenvolvimento de um
método analítico, para a quantificação do LPSF/AC-04 por espectrofotometria-UV,
aplicado ao fármaco e dele nanoencapsulado em lipossomas. Inicialmente, um método
espectrofotométrico UV para o doseamento do LPSF/AC-04 em lipossomas foi
desenvolvido avaliando os seguintes parâmetros preconizados pelo ICH: linearidade,
precisão, exatidão, robustez e limites de detecção e quantificação. O LPSF/AC-04 foi
determinado em metanol a 250 nm, onde o coeficiente de absortividade (ε) encontrado
foi 7,60 × 104 L.mol−1.cm−1. O método espectrofotométrico para determinação do
LPSF/AC-04 em lipossomas foi linear na faixa de concentração de 0,3 a 2 μg/mL
Absorbância = 0,18068 x [LPSF/AC-04] (μg/mL) + 0,00348 e o coeficiente de
regressão encontrado foi (r2 = 0,9995). O método proposto foi sensível para os limites
de detecção e quantificação foram de 0,047 e 0,143 μg/mL, respectivamente. O método
se mostrou preciso, já que todas as amostras analisadas apresentaram coeficiente de
variação menor que 5 % e estatisticamente não houve diferença entre as concentrações
teóricas e práticas. O método se apresentou robusto, sem diferenças estatisticamente
significativas frente à variação do fabricante do solvente e da temperatura. Na exatidão
foi possível observar a recuperação do fármaco que variou entre 99,4 ± 0,67 % a 100,5
± 1,91% estando dentro dos limites recomendados. O teor e a eficiência de
encapsulação do LPSF/AC-04 em lipossomas foi de 104,44 ± 1,56% e de 99,68 ±
0,24%, respectivamente. O método analítico proposto mostrou-se, portanto, simples,
rápido, exato, preciso e de baixo custo podendo ser utilizado para análises de rotina do
LPSF/AC-04 matéria prima e em formulações farmacêuticas, como por exemplo, os
lipossomas
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Costa, Salvana Priscylla Manso. "Estudo de Pré-formulação de um novo agente esquistossomicida 3-(4-cloro-benzil)-5-(4-nitro-benzilideno)- imidazolidina-2,4-diona (LPSF/FZ4)." Universidade Federal de Pernambuco, 2012. https://repositorio.ufpe.br/handle/123456789/10342.
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Previous issue date: 2012-02-06<br>CNPq<br>O protótipo 3-(4-cloro-benzil)-5-(4-nitro-benzilideno)-imidazolidina-2,4-diona (LFPS/FZ4) é um análogo imidazolidínico que apresenta potencial atividade esquistossomicida. Diante do fato de que a esquistossomose é uma doença negligenciada que acomete mais de 200.000 pessoas no mundo e que a quimioterapia representa o maior instrumento para seu controle, na quimioterapia apresenta o praziquantel como fármaco de escolha, no entanto, o mesmo é relativamente tóxico devido à sua baixa solubilidade, bem como, contar com apenas um fármaco é, certamente, uma situação perigosa, especialmente no que diz respeito à resistência do parasita. Neste contexto, faz-se de extrema importância a busca por novas moléculas bioativas como alternativa terapêutica para o tratamento da esquistossomose. Sendo assim, o objetivo deste trabalho foi realizar um estudo de preformulação do LPSF/FZ4 visando o desenvolvimento de uma forma farmaceutica sólida. O estudo abrangeu a caracterização físico-química, estabilidade térmica e compatibilidade fármaco-excipiente por técnicas espectroscópicas (UV, IV, RMN e MS), MS, temoanalíticas (DTA, DSC e TG), bem como DRX, tamanho de partícula e área superficial além de ferramentas analíticas como equação de Van't Hoff e modelo de Ozawa para a avaliação da cinética de decomposição térmica. Os resultados obtidos da avaliação físico-química do LPSF/FZ4 frente a diferentes técnicas permitiu caracterizá-lo do ponto de vista morfológico e químico. O protótipo apresentou-se com 98% de pureza, funde a 228°C (ΔH= -178 Jg-1) com pico endotérmico de fusão caracteristico de uma forma cristalina que foi corroborado pela difração de raios-X onde revelou o padrão cristalino do fármaco, o qual também foi demonstrado pela eletromicrografia, como cristais aciculares bem definidos, o composto manteve-se termicamente estável até 320 ºC onde a degradação térmica ocorreu em um estágio entre 320 – 370 ºC com perda de massa em torno de 60%. Foi considerado um pó finíssimo com tamanho de partícula entre 10 e 100 μm, bem como uma área superficial em torno de 5,2277 m²/g. No entanto, apresenta baixa solubilidade aquosa (0,01 mg/mL), devido a sua conformação estrutural apresentar fortes forças de atração interatômica, porém mostrou-se facilmente solúvel em acetona e acetonitrila. A equação Arrhenius e modelo de Ozawa mostrou um comportamento cinético de ordem um para a decomposição do protótipo, e um tempo de validade provisória calculado de quatro meses a 25 °C. O estudo de compatibilidade evidenciou possíveis interações químicas entre o LSPF/FZ4 com a lactose e o polissorbato, ambas associadas a diminuição da estabilidade térmica do protótipo, com redução considerável da temperatura de degradação e de fusão. Concluí-se que a abordagem integrada da tecnologia farmacêutica permitiu obter resultados com enfoques mais específicos e direcionados no sentido da obtenção de um produto farmacêutico estável e seguro.
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Medeiros, Giovanna Christinne Rocha de. "Determinação espectrofotométrica do pKa e desenvolvimento de dispersões sólidas da nova entidade química LPSF/FZ4: um promissor agente esquistossomicida." Universidade Federal de Pernambuco, 2013. https://repositorio.ufpe.br/handle/123456789/13201.
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Previous issue date: 2013-07-25<br>FACEPE; Emerging Leaders in the Americas Program (ELAP) (Governo do Canadá)<br>A nova entidade química LPSF/FZ4 (4-cloro-benzil)-5-(4-nitro-benzilideno)-imidazolidina-2,4-diona) foi sintetizada pela Universidade Federal de Pernambuco (Brasil, Recife-PE) como uma alternativa para o tratamento da esquistossomose, uma doença negligenciada. Por se tratar de um protótipo, várias propriedades físico-químicas são praticamente desconhecidas, como, por exemplo, o seu pKa. O conhecimento desta propriedade é de fundamental importância para o desenvolvimento de medicamentos, uma vez que esta pode afetar a solubilidade e a permeabilidade do protótipo, aspectos importantes para a sua absorção, distribuição, metabolismo e excreção no organismo. Além disso, o LPSF/FZ4 possui limitada solubilidade em água (S<1μg/mL), sendo bem reconhecido que a baixa solubilidade de um fármaco muitas vezes limita sua taxa de dissolução e sua biodisponibilidade. Uma alternativa para esse entrave é a utilização das dispersões sólidas (DS). A fim de conhecer melhor o protótipo, o presente estudo objetivou a determinação do pKa do LPSF/FZ4 e, visando melhorar sua dissolução, investigou a técnica de DS. Utilizou-se o método espectrofotométrico com auxílio do equipamento SiriusT3 para determinação do pKa. Uma análise teórica da estrutura da molécula também foi realizada. Dessa forma, descobriu-se que o LPSF/FZ4 é uma base fraca monoprótica (BH+) com um grupo carbonila na posição 4 do anel imidazolidínico de pKa 8,47. Com um estudo de dissolução in vitro foi verificado que, com valores de pH superiores a 8,47, o LPSF/FZ4 apresenta-se predominantemente na sua forma neutra (B). À medida que o pH diminui, a base começa a se protonar (BH+), aumentando acentuadamente sua solubilidade. Para o desenvolvimento de DS com o protótipo, estudos teórico e prático preliminares permitiram selecionar o HPMC K4M, o PVP K-90, o PVPVA 64 e o SOLUPLUS. As DS com esses carreadores foram preparadas pelo método do solvente. A análise de Difração de raios-X (DRX) mostrou a concentração máxima de LPSF/FZ4 capaz de se manter amorfa em cada carreador, logo, indicou qual seria o último sistema de DS obtido com cada carreador. Através dos estudos de dissolução in vitro em condição non-sink utilizando o equipamento SiriusT3, e de estabilidade acelerada, pôde-se selecionar as dispersões sólidas mais promissoras para compor um futuro medicamento com o LPSF/FZ4. Percebeu-se que o sistema DS SOLUPLUS - LPSF/FZ4 10% pode aumentar em até 3000 vezes o desempenho do protótipo no estudo de dissolução, além de se mostrar estável. Por esse motivo, esse sistema revelou-se o mais promissor. O sistema DS PVP K-90 – LPSF/FZ4 10% obteve o segundo melhor resultado no estudo de dissolução in vitro e, assim, também foi selecionado. Prosseguiu-se com a caracterização física e química das DS com PVP K-90 e SOLUPLUS através das técnicas de Calorimetria Exploratória Diferencial, Microscopia de Polarização de Estágio à Quente, Microscopia de Polarização e Espectrofotometria de Absorção na Região do Infravermelho, permitindo verificar, por exemplo, que as DS com o SOLUPLUS formaram ligações de hidrogênio mais fortes com o protótipo do que o as com PVP K-90. Dessa forma, o presente estudo foi de grande importância, pois forneceu informações relevantes para a concepção racional de medicamentos com a nova entidade química, e obteve uma formulação adequada para superar as limitações de solubilidade do LPSF/FZ4.
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Olofsson, Emma. "EN ANALYS AV, OCH DISKUSSION OM, LÄROPLANEN LPF 94S GRUNDLÄGGANDE TEORETISKA KUNSKAPSSYN." Thesis, Halmstad University, School of Teacher Education (LUT), 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-1292.
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<p>Föreliggande uppsats har kritiskt granskat, analyserat och diskuterat Läroplanens teoretiska kunskapssyn. Om analysen håller så anser jag mig ha visat vilka resonemang, utifrån den kognitiva relativismen, som Lpf 94 bygger på. </p><p> Hur den kognitiva relativismen kommer fram till att kunskap är relativ kan se lite olika ut. Minst tre underliggande teser kan urskiljas vilka alla kan ligga till grund för Lpf 94s kunskapssyn. Dessa är kunskapssociologisk relativism, epistemisk relativism och ontologisk relativism. Alla förnekar de, var för sig, minst ett av tre de nödvändiga villkoren i den traditionella analysen av kunskap, vilken innebär att kunskap är sann berättigad tro.</p><p> Jag har även presenterat, analyserat samt diskuterat de elementära och logiska motsägelser som följer en relativistisk kunskapssyn. Dessa är av den omfattningen att det kan finnas tillräckliga skäl att förkasta en relativistisk kunskapssyn oavsett vilket relativistiskt resonemang som ligger till grund för Lpf 94s relativa kunskapssyn. </p><p> Min slutsats är att synen på att teoretisk kunskap är relativ inte håller och bör förkastas, vilket innebär att läroplanen i framtiden bör bygga på en objektiv kunskapssyn.</p>
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ALMEIDA, JÚNIOR Antônio Sérgio Alves de. "Síntese, Caracterização Estrutural e Avaliação da Atividade Esquistossomicida de Imidazolidinas Dissubstituídas." Universidade Federal de Pernambuco, 2014. https://repositorio.ufpe.br/handle/123456789/12535.
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Previous issue date: 2014-02-25<br>FACEPE<br>A esquistossomose é reconhecida pela Organização Mundial de Saúde, como
um grave problema de saúde pública, acometendo os países da África, América
Latina, Caribe e Oriente Médio. No Brasil, é encontrada a espécie Schistosoma
mansoni, com estimativas de 6 a 8 milhões de indivíduos infectados. O fármaco
utilizado para a quimioterapia desta parasitose é o praziquantel (PZQ). Contudo,
são relatados na literatura casos de possíveis cepas de S. mansoni resistentes a
esse tratamento, havendo a necessidade de desenvolver novos medicamentos
mais eficazes e menos tóxicos para o tratamento da esquistossomose
mansônica. O núcleo imidazolidínico é um heterociclo pentagonal, farmacóforo
importante presente em vários compostos biologicamente ativos, conhecido na
literatura pelo seu amplo espectro de atividades biológicas, inclusive a atividade
esquistossomicida. Neste trabalho foi realizada a síntese e comprovação
estrutural de novos derivados imidazolidínicos das séries LPSF/FZ e LPSF/RH e
a sua avaliação esquistossomicida in vitro frente a vermes adultos de S.
mansoni. Assim foram sintetizados oito novos compostos finais, onde
inicialmente sintetizou-se o 1º intermediário (LPSF/FZ-1) através de uma reação
de N-alquilação. Em seguida, a síntese do 2º intermediário (LPSF/FZS-1)
através de uma reação de tionação. A formação dos quatro compostos finais da
série LPSF/FZ (5-benzilideno-3-benzil-imidazolidina-2,4-diona) se deu através de
uma reação de condensação de Knoevenagel entre o 1º intermediário e os
benzaldeídos substituídos em meio etanólico. Para a formação dos quatro
compostos finais da série LPSF/RH (5-benzilideno-3-benzil-4-tioxo-imidazolidin-
2-ona), utilizou-se o 2º intermediário e os benzaldeídos através de uma reação
de condensação de Knoevenagel. Sete derivados imidazolidínicos (LPSF/RH-38,
LPSF/RH-39, LPSF/RH-40, LPSF/RH-41, LPSF/FZ-20, LPSF/FZ-21 e LPSF/FZ-
24) foram avaliados quanto ao efeito na viabilidade celular através da linhagem
de células macrofágicas J774 e atividade in vitro frente a vermes adultos de S.
mansoni. Os compostos sintetizados apresentaram bons rendimentos e foram
caracterizados pelas técnicas espectroscópicas (IV, RMN e Massas). Os
derivados imidazolidínicos demonstraram ser menos citotóxicos quando
comparados ao PZQ. Dentre os compostos testados in vitro, o LPSF/RH-38 foi o
que demonstrou um melhor resultado, apresentando 100% de mortalidade na
concentração de 100 μg/mL no sexto dia de observação. A presença do átomo
de enxofre na posição 4 da imidazolidina nos compostos da série LPSF/RH foi
um fator importante para o aumento da atividade esquistossomicida, ao contrário
dos compostos da série LPSF/FZ, que apresentam um átomo de oxigênio na
mesma posição. Diante dos resultados obtidos, verificamos uma atividade
esquistossomicida promissora dos derivados imidazolidínicos sendo ainda
necessários os testes in vivo para uma melhor avaliação destes compostos.
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Vieira, Amanda Carla Quintas de Medeiros. "Incremento da solubilidade aquosa de um novo derivado tiazolidínico (LPSF/GQ-130) para terapias anti-inflamatórias utilizando a técnica de dispersões sólidas." Universidade Federal de Pernambuco, 2013. https://repositorio.ufpe.br/handle/123456789/13198.
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Previous issue date: 2013-02-25<br>CAPEs<br>O LPSF/GQ-130 é uma tiazolidinodiona que apresentou atividade anti-inflamatória promissora em estudos in vivo, porém, sua insolubilidade aquosa repercute em dissolução e absorção inadequada no organismo. Assim, este trabalho objetivou incrementar esta propriedade através da técnica de dispersões sólidas (DS). A caracterização química e físico-química do protótipo permitiu a confirmação da molécula através das técnicas espectrométricas tradicionais, bem como a determinação da sua faixa de fusão (171,3 a 176,5°C) e pureza (99,37% ± 0,19), através da análise térmica. A obtenção da cinética de degradação térmica não isotérmica elucidou sua energia de ativação (95,14 KJ.mol-1), ordem de reação (0) e temperatura de decomposição térmica (238,3 a 297,4°C). Estudos preliminares de estabilidade identificaram intensa susceptibilidade a degradação em condições básicas e oxidativas. Os aspectos físicos da NEQ envolvem estruturas cristalinas (5,5; 16,3 e 44,18° 2ϴ), de formato acicular, com diâmetro médio dos aglomerados de 12,48 μm. A validação do método de doseamento por Cromatografia Líquida de Alta Eficiência (CLAE-DAD) foi realizada em coluna C18 (25 cm x 4mm , 5μm ) fase reversa, com fase móvel composta por acetonitrila:H2O (85:15) e fluxo de 2 mL.min-1, sendo a solubilidade aquosa do protótipo inferior ao limite de quantificação do método (0,0001 μg.mL-1). O desenvolvimento do método de dissolução apresentou o meio de pH 1,2 com 1% de lauril sulfato de sódio como condição ótima para a execução das análises. As dispersões sólidas foram obtidas través do método do solvente (diclorometano), utilizando como matriz a hidroxipropilmetilcelulose (HPMC). O lote HPMC02 apresentou incremento de 28,57 e 11% na eficiência de dissolução (ED%) da DS binária (120 min), em comparação ao LPSF/GQ-130 isolado à mistura física (MF), respectivamente. A solubilidade da DS em água e em meio de dissolução foi incrementada em 7,7x106% e 1,99x103%, respectivamente. A obtenção dos sistemas ternários demonstrou maior ED% para a MF do que para a DS (47,45 e 44,97, respectivamente). Assim, pode-se concluir que o método empregado na obtenção da DS foi eficiente para a obtenção de DS binárias, entretanto, não repercutiu em melhoras para o sistema ternário. Ambos os sistemas constituem matérias-primas aperfeiçoadas para o desenvolvimento tecnológico de formas farmacêuticas a base deste protótipo.
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Zhang, Tan Tan. "Sub-nano-watt subthreshold-biased source-follower-based LPF for biopotential signal acquisition systems." Thesis, University of Macau, 2010. http://umaclib3.umac.mo/record=b2182899.
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Sandell, Marie-Louise. "Entreprenörskap – Vår tids skolpolitiska filosofi? En ideologikritisk analys av Lpf 94 och Skola 2011." Thesis, Malmö högskola, Lärarutbildningen (LUT), 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:mau:diva-27942.
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The aim of this Master’s thesis is to examine the ideological currents that have influenced the swedish school system since the 1990's. The background of my interest is the lively debate in schools and media about the new School reform 2011. My hypothesis is that education in 2011 largely will be influenced by neoliberal and neoconservative values.The method I`ve used is discourse and ideology critique, which examines the relationship between rhetoric and power. These concepts are useful to explain the ideological change in different policy documents and in curricula, for example Lpf 94 and School 2001.The theoretical framework is based primarily on the neoliberal and the neoconservative agenda, which are two distinct political rationalities in the contemporary postmodern world. Alongside this framework I have used scientific, educational, philosophical, sociological and cultural literature. The reason that I have included philosophical texts, is to put education issues in a wider contextOn the internationally published research articles there are literature, which criticize the neoliberal and neoconservative education discourse. This ideological thinking appears through a number of American scientists, such as Michael Apple, who advocate a different kind of education - a corrective to the mainstream - education, that denies ―grand narratives‖ such as class oppression in favor of the pedagogy based on control. Their theories are interesting and seem to be sustainable but are not very much discussed in the Swedish educational debate or education plans today.The conclusion is that the swedish school system is influenced by neoliberal and neoconservative values, through the plans to establish law and order, measurable criteria and entrepreneurship in education.
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Andersson, Johanna. "Grannspråken i undervisningen : en kvalitativ intervjustudie." Thesis, Uppsala universitet, Institutionen för nordiska språk, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-220045.
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Uppsatsen behandlar grannspråken i svenskundervisningen. Studiens huvudsyfte var att undersöka gymnasielärares inställning till grannspråk. Ett av delsyftena var att undersöka vilken plats grannspråksundervisning hade i de senaste två läroplanerna samt om förändring skett i och med den nu gällande läroplanen Lgy 2011. Ett andra delsyfte var att ta reda på hur Skolverket motiverade att grannspråken inte fanns med under det centrala innehållet (anvisningar om kursinnehåll) i kursen Svenska 1. Metoden som användes var kvalitativ och materialet inskaffades genom intervjuer med fem lärare samt genom närläsning och jämförelse mellan kursplanerna. Resultatet visade att det i den nya läroplanen Lgy 2011 ges lite större plats åt grannspråken och att innehållsformuleringarna blivit tydligare. Grannspråken finns nu med i alla betygssteg, vilket inte var fallet i Lpf 94. Skolverket motiverade att grannspråken inte finns med i kursen Svenska 1 på grund av att den redan var så pass innehållstung samt att elever förväntades ha fått grundläggande kunskaper från grundskolan. Vad gäller lärares inställning till grannspråken visade resultaten att merparten av lärarna i studien undervisade i grannspråk men att tiden de lade på området skiljde sig stort. Lärarna motiverade sin undervisning främst genom att hänvisa till Skolverkets skrivelser i läroplanen, men de flesta gav även ytterligare motiveringar. Lärarna upplevde även att den undervisning de fått under lärarutbildning gav dem tillräckliga kunskaper för att bedriva undervisning. De flesta lärare uttryckte att de personligen inte tyckte att grannspråken var så roliga att undervisa i men gjorde det trots detta. Min slutsats är att undervisning i grannspråk inte är likvärdig i skolorna beroende på att den tid som läggs på området varierar så.
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VALÉRIO, Raphael Dutra. "Desenvolvimento e validação de um método analítico para determinação quantitativa do derivado tiazolidinico (LPSF/AC-23) com atividade antitumoral em plasmas de ratos." Universidade Federal de Pernambuco, 2011. https://repositorio.ufpe.br/handle/123456789/9312.
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Previous issue date: 2011<br>Conselho Nacional de Desenvolvimento Científico e Tecnológico<br>O derivado tiazolidínico (LPSF/AC-23) sintetizado pelo Laboratório de Planejamento e
Síntese de Fármacos da Universidade Federal de Pernambuco apresentou importante atividade
antitumoral em camundongos albinos Swiss. Tal resultado despertou o interesse e a
necessidade do desenvolvimento e validação de um método bioanalítico para determinação do
LPSF/AC-23 em fluidos biológicos para possibilitar a posterior determinação dos parâmetros
farmacocinéticos desta molécula candidata a fármaco. Neste contexto, um método
bioanalítico sensível e seletivo foi desenvolvido e validado utilizando a técnica de
Cromatografia Líquida de Alta Eficiência acoplada a um detector ultravioleta (CLAE-UV)
para quantificação desta molécula em plasma de ratos. O método envolveu a preparação da
amostra utilizando extração por precipitação protéica com acetonitrila e uma tiazolidinadiona
(LPSF/GQ 113-B) foi utilizada como padrão interno (PI). A separação e quantificação do
LPSF/AC-23 e PI foi realizada utilizando uma fase móvel composta por uma mistura de
acetonitila/metanol/tampão fosfato 5 mM (pH 6,0) (55:30:15) eluida de forma isocrática
através de uma coluna analítica Phenomenex® (C18, 5μm, 150mm x 4.6mm) a uma
temperatura de 40°C e fluxo de 1mL/min. O comprimento de onda para detecção foi de 249
nm. A curva de calibração foi linear na faixa de 100-10000 ng/mL. A precisão intra e inter-dia
apresentou valores de Desvio Padrão Relativo preconizados pela ANVISA, e a exatidão
expressa pelo erro relativo (ER) variou de 3,49 a 7,67%. A recuperação foi de 92,25% para o
analito e 89,67% para o PI. Desta forma, o método proposto pode ser aplicado para
determinação quantitativa do LPSF/AC-23 em plasma de ratos em estudos farmacológicos,
toxicológicos, farmacocinéticos e de biodisponibilidade
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Lundholm, Patrik. "Utbildningsfilosofi i läroplan och kursplan : En textanalys av Lgy 70, Lpf 94 och Gy 2011." Thesis, Umeå universitet, Institutionen för tillämpad utbildningsvetenskap, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-129668.
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The purpose of this study is to categorize what philosophical thoughts about knowledge and learning that have affected the general curriculum and the syllabus for political science in the swedish educational system, from 1970 up to 2011. The study utilizes the theories of Tomas Englund regarding perennialism, essentialism, progressivism and reconstructivism and the theories of Geir Biesta about socialisation, qualification and subjectification. These theories are applied to three different curriculums and syllabi in Sweden The results are that all curriculums and syllabi contain essentialism. The first studied curriculum, Lgy 70, is mostly affected by progressive thoughts while the two following, Lpf 94 and Gy2011, are more affected by reconstructivism. Regarding Geir Biestas theories the curriculums seem to gradually shift from socialisation towards subjectification.
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Stamford, Henrique da Silva Guerra Aline. "Estudo das Atividades Anti-inflamatória e Antinociceptiva dos Derivados Indol-imidazolidínicos 5-(1H-Indol-3-il-metileno)-2-tioxo-imidazolidin-4- ona (LPSF/NN-56) e 3-(4-Bromo-benzil)-5-(1H-indol-3-il-metileno)-2- tioxo-imidazolidin-4-ona(LPSF/NN-52)." Universidade Federal de Pernambuco, 2011. https://repositorio.ufpe.br/handle/123456789/9111.
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Previous issue date: 2011<br>Faculdade de Amparo à Ciência e Tecnologia do Estado de Pernambuco<br>A inflamação é uma resposta vital provocada por patógenos, danos físicos, isquemia,
injúrias tóxicas ou auto-imunes com o objetivo de proteger o organismo. É um processo
complexo, incluindo atividades de vários tipos de células e dezenas de mediadores
protéicos e lipídicos. A fase inicial da inflamação inclui mudanças no fluxo sanguíneo
local e acumulação de várias células inflamatórias (neutrófilos, células dendríticas,
monócitos, mastócitos e linfócitos). Posteriormente, patógenos, debris celulares e
células inflamatórias precisam ser removidas e a integridade e funcionamento normal do
tecido restaurado. Apesar do avanço no conhecimento da fisiopatologia da inflamação,
os medicamentos atuais ainda apresentam sérios efeitos adversos. Neste estudo, nos
propomos a avaliar a atividade anti-inflamatória e antinociceptiva de derivados indolimidazolidínicos
(LPSF/NN-52 e LPSF/NN-56) e determinar as concentrações do TNF-
α e IL-1β no exsudato inflamatório de animais tratados com os compostos em estudo.
Para a avaliação da atividade anti-inflamatória, foram utilizados testes da fase aguda
como, bolsão de ar subcutâneo, peritonite e pleurisia induzidos por carragenina e
permeabilidade vascular induzida por ácido acético. Para avaliação do efeito
antinociceptivo foram realizados os ensaios da nocicepção induzida por ácido acético,
formalina e placa quente. No teste do bolsão de ar os melhores resultados foram obtidos
com o LPSF/NN-52 (10mg/kg) e LPSF/NN-56 (3mg/Kg) com inibição da migração
leucocitária de 72 e 81%, respectivamente em relação ao grupo controle. A
indometacina (10mg/kg; 87% de inibição) foi usada como fármaco de referência. Na
peritonite, os compostos LPSF/NN-52 (10mg/kg) e LPSF/NN-56 (3mg/kg) inibiram a
migração leucocitária em 56 e 55%, respectivamente, em relação ao controle. O
fármaco padrão indometacina apresentou inibição de 58%. Em relação à avaliação das
citocinas pró-inflamatórias em ambos os testes, as substâncias em estudo diminuíram a
concentração de TNF-α e IL-1β. No teste da pleurisia, as substâncias também inibiram a
migração leucocitária LPSF/NN-52 (49%) e LPSF/NN-56 (39%) em relação ao grupo
controle, porém sua inibição foi inferior aos padrões dexametasona (71%) e
indometacina (65%). Os compostos testados diminuíram a permeabilidade vascular
induzida por ácido acético. Na nocicepção induzida por ácido acético, as substâncias
apresentaram diminuição no número de contorções abdominais em relação ao grupo
controle, onde o LPSF/NN-52 inibiu a nocicepção em 52% e LPSF/NN-56 inibiu 63%.
O padrão para este teste foi o diclofenano (68%). No teste da formalina, os compostos
testados apresentaram efeitos apenas na segunda fase. No teste da Placa quente nenhum
dos derivados apresentou inibição da nocicepção. Desta forma, os resultados indicam
que os derivados indol-imidazolidínicos testados apresentaram atividade antiinflamatória
e antinociceptiva promissoras, provavelmente através da modulação do
sistema imune. Sugere-se que a atividade antinociceptiva dos derivados indolimidazolidínicos
seja decorrente de mecanismos periféricos, atuando apenas na dor
inflamatória
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SILVA, Amanda Karolina Soares e. "Avaliação do mecanismo de ação do derivado tiazolidínico LPSF/GQ-02 sobre a resistência à insulina, esteatose hepática e aterosclerose." Universidade Federal de Pernambuco, 2015. https://repositorio.ufpe.br/handle/123456789/24275.
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Previous issue date: 2015-06-30<br>CNPQ<br>A doença do fígado gorduroso não-alcoólico (NAFLD) refere-se a um amplo aspectro de doenças hepáticas causadas pelo depósito de gordura nas células do fígado na ausência do consumo de álcool. Provas evidentes demonstram que a NAFLD desempenha um papel relevante na patogênese da aterosclerose. As tiazolidinadionas (TZDs) agem como meléculas sensibilizadoras da ação da insulina e têm sido utilizadas no tratamento de pacientes com diabetes do tipo 2 e outras condições de resistência à insulina, incluindo a NAFLD. Uma vez que a aterosclerose e NAFLD podem compartilhar mecanismos comuns, estratégias terapêuticas similares poderiam ser empregadas no tratamento de ambas as doenças. No presente estudo, foi avaliado a atividade biológica de LPSF/GQ-02 na patogênese da NAFLD e aterosclerose. Os resultados obtidos com um modelo murino de NAFLD indicaram que a LPSF/GQ-02 foi eficaz em melhorar a arquitetura hepática, diminuindo a acumulação de gordura, reduzindo a quantidade de colágeno, diminuindo a inflamação através da redução da IL-6, iNOS, COX-2 e F4/80, e aumento da expressão de proteínas de IκBα citoplasmática, NFkB-65, eNOS e IRS-1 em camundongos deficientes do receptor de LDL (LDLr-/-). Além disso, ambos os tratamentos (15 e 30 dias) com LPSF/GQ-02 resultou em uma redução de colágeno nas lesões ateroscleróticas. Adicionalmente, o tratamento durante 15 dias também diminuiu os níveis de mRNA de CD40, MCP-1, ABCG1, e aumentou os níveis do PPARα, uma vez que o tratamento com 30 dias reduziu os níveis das proteínas LOX-1, p-IκBα e p-NFkB. Estes resultados sugerem uma ação direta da LPSF/GQ-02 sobre os fatores que afetam a inflamação, resistência à insulina e acumulação de gordura no fígado, bem como uma ação sobre a composição e crescimento das lesões ateroscleróticas nos camundongos LDLr-/-. Sendo assim, nossos dados apoiam os resultados anteriores, que mostraram as propriedades anti-inflamatórias de LPSF/GQ-02 e reforça o potencial terapêutico desta TZD para o tratamento da aterosclerose e desordens relacionadas a inflamação.<br>Non-alcoholic fatty liver disease (NAFLD) refers to a wide spectrum of liver diseases caused by fat deposit in the liver cells in the absence of excess alcohol consumption. Compelling evidence has demonstrated that NAFLD plays a relevant role in the pathogenesis of atherosclerosis. Thiazolidinediones (TZDs) act as an insulin sensitizer and have been used in the treatment of patients with type 2 diabetes and other insulin-resistant conditions, including NAFLD. Since atherosclerosis and NAFLD might share common mechanisms, similar therapeutic strategies could be employed in the treatment of both disorders. In the present study, we evaluated the biological activity of LPSF/GQ-02 on the NAFLD and atherosclerosis pathogenesis. The results obtained with an NAFLD murine model indicated that LPSF/GQ-02 was effective in improving the hepatic architecture, decreasing fat accumulation, reducing the amount of collagen, decreasing inflammation by reducing IL-6, iNOS, COX-2 and F4 / 80, and increasing the protein expression of IκBα, cytoplasmic NFκB-65, eNOS and IRS-1 in mice deficient in the LDL receptor (LDLr -/-). In addition, both treatment protocols (15 and 30 days) with LPSF/GQ-02 resulted in lower collagen density in the atherosclerotic lesions. Moreover, the treatment for 15 days also decreased mRNA levels of CD40, MCP-1, ABCG1 and upregulated PPARα, whereas the 30-days treatment reduced the protein levels of LOX-1, p-IκBα and p-NFκB. These results suggest a direct action by LPSF/GQ-02 on the factors that affect inflammation, insulin resistance and fat accumulation in the liver of these animals, and affects the composition and growth of atherosclerotic lesions in LDLr -/- mice. Our data also support previous findings showing anti-inflammatory properties of LPSF/GQ-02 and reinforce the therapeutic potential of this TZD for treating atherosclerosis and inflammation-related disorders.
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Chen, Xi. "Oxidatively Truncated Ether Phospholipid: Synthesis, Detection in LDL and Biological Activities." online version, 2008. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=case1192974399.
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Yngve, Annethe. "Motivation inom gymnasieskola och föreningsidrott - gymnasieelevers uppfattning av motivation i korrespondens med skolans och idrottens styrdokument." Thesis, Halmstad University, School of Teacher Education (LUT), 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-1720.
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<p>Syftet med föreliggande uppsats är att undersöka gymnasieungdomars uppfattning av motivation i relation till kommunikationen av uppgifter och mål i styrdokumenten: Lpf 94 och Idrotten vill. Studien utgår från bandinspelade kvalitativa intervjuer av nio idrottligt aktiva gymnasieungdomar. Faktorer som sätts i samband med motivation av ungdomarna har genom hermeneutisk forskningsansats tolkats, i relation till faktorer i styrdokumnetens kommunikation av uppgifter och mål och mot bakgrund av tidigare forskning. Slutsatsatsen av studien är att gymnasieskola och idrott baserar och styr motivation mot verksamhetens kommunicerade uppgifter och mål i ett framtidsperspektiv som legitimeras av samhällsnytta. Innebörden av motivation för ungdomarna är baserad på subjektiva känslor, i ett här-och-nu perspektiv, och betraktas som en del av ungdomarnas förändrings- och självständighetsprocess. Informanterna härleder motivationens uppkomst till det egna valet, vilket är en skenbar frihet. Inom gymnasieskola och idrott är det vuxenvärldens normer som gäller. Kommunikationen beträffande att behålla eller förlora motivation är i det närmaste obefintlig i styrdokumenten utan delegeras till lägre nivåer inom verksamheterna. På lokal nivå inom idrotten exponeras och bedöms förmågor, tillkortakommanden, prestationer och resultat från det att de aktiva är mycket unga. Även inom skolan sker bedömningar på lokal nivå, men med en hög grad av diskretion och ett betygssystem som tar sin början vid grundskolans senare del. Idrottens utbildningssystem framträder som avsevärt mer elitistiskm och auktoritärt än skolans.</p>
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Hoffmann, Anja, and Emma Persson. ""Det är den främsta grejen - att lära ut" : En kvalitativ studie om elevers föreställningar gällande lärarens roller i jämförelse med Lpf 94." Thesis, Linnéuniversitetet, Institutionen för pedagogik, psykologi och idrottsvetenskap, PPI, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-12853.
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Syftet med studien är att undersöka hur väl Läroplanen för de frivilliga skolformerna (Lpf 94) stämmer överens med gymnasieelevers föreställningar gällande lärarens roll som ledare, relationsskapare, kunskapsförmedlare och moraliska/etiska uppdrag. Metoden som ligger till grund för studien är intervjuer i fokusgrupper med gymnasieelever och en dokumentanalys av Lpf 94. Totalt deltog 24 stycken elever från fyra olika gymnasieskolor. Resultatet visar att elevernas föreställning om lärarens roller i stora drag stämmer överens med Lpf 94:s definitioner, exempelvis lärarens förmåga att använda sig av varierande undervisningsmetoder och ge möjlighet till reellt elevinflytande. Lpf 94 och elevernas föreställningar gällande läraren som relationsskapare skiljer sig åt. Eleverna anser att elev – lärarrelationen är betydelsefull medan Lpf 94 inte explicit nämner det. Studiens resultat visar vidare att mycket av lärarens praktiska arbete både skiljer sig från elevernas föreställningar och Lpf 94:s direktiv. Detta ger indikationer på att problematiken ligger vid implementeringen av Lpf 94. För vidare forskning hade det varit intressant att undersöka implementeringsprocessen.
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Laine, Jonas. "Miljöperspektiv i historieläroböcker - finns det? : En jämförande undersökning av två gymnasieläroböcker i historia." Thesis, Högskolan Dalarna, Pedagogiskt arbete, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:du-1632.
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Jag hade inte kommit i kontakt med någon undersökning som fokuserat på läroböckers behandling av miljön, vilket lämnade en lucka i forskningen. Syftet med undersökningen blev därmed att försöka fylla denna lucka, vilket skulle uppnås genom att studera två gymnasieläroböcker i historia och deras uttryck för miljöperspektiv. Undersökningens resultat visar att författarna till båda böckerna ger uttryck för miljöperspektiv, men att det är Epos författare som gör detta mest konsekvent. I båda böckerna behandlas människans samspel med naturen främst i äldre kulturer, men även i stor utsträckning i samband med industrialiseringen samt under miljödebatten som växte fram på 1960-talet. Vad det gäller karaktären på de miljöperspektiv som uttrycks så utgår majoriteten av dessa från hur naturen och de omgivande förutsättningarna påverkat människan och dess samhällen. Den andra sidan av myntet, hur människan påverkat naturen, kommer därmed till viss del i skymundan. Den tidsdimension som anläggs i miljöperspektiven är i båda böckerna främst i dåtid och förklarar därmed hur människan påverkat naturen och vice versa i det samhälle som behandlas. Vad det gäller kopplingen mellan då-nu-sedan så är det författarna till Alla tiders historia Maxi som ger uttryck för flest sådana miljöperspektiv, vilket görs i behandlingen av tiden efter 1965.
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Li, Heli. "RF LOW PASS FILTER DESIGN AND FABRICATION USING INTEGRATED PASSIVE DEVICE TECHNOLOGY." Master's thesis, University of Central Florida, 2006. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/4340.
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In this thesis, the whole process of design a low pass filter (LPF) for the wireless communication application has been presented. Integrated passive device technology based on GaAs substrate has been utilized to make the LPF. Schematic simulation and electromagnetic simulations are extensively used in the design process. EM simulation is used in the selection of layout design and processing parameters for design optimization of both the inductors and IPD harmonic filters. The effective use of EM simulation enables us to realize the successful development of high performance harmonic filters. To make the optimization be more flexible and also for a deeper understanding of the optimization theory, optimization using genetic algorithm is also implemented. The weight of each targets are adjustable, and a non-uniformly distributed goal for the harmonic rejection range is introduced to achieve better optimization results. The embedded LPF is built and measurement results show good agreement with the simulation data. This kind of very compact, high performance harmonic filters can be used in radio transceiver front-end modules. The realized harmonic filters have insertion loss less than 0.6 dB and harmonic rejections greater than 25 dB with a compact die size of 0.8 mm2.<br>M.S.E.E.<br>School of Electrical Engineering and Computer Science<br>Engineering and Computer Science<br>Electrical Engineering
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Trulsson, Linnea. "Den ideologiska läroplanen : En kvalitativ studie av kunskapsdiskurser i Lgy 70, Lpf 94 och Gy 2011." Thesis, Linnéuniversitetet, Institutionen för utbildningsvetenskap (UV), 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-44466.
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Syftet med studien är att genom en kvalitativ och komparativ textanalys granska kunskapsdiskurser i läroplanerna Lgy 70, Lpf 94 och Gy 2011 för att urskilja förändringar. Kunskapsdiskurserna är indelade följande: teoretisk, praktisk och ideologisk kunskap, och fokus är på läroplanernas allmänna del och kursplan för Svenska. I centrum står diskursteori, läroplansteori samt epistemologi vid tolkning av resultatet. Resultatet visar att det har skett en viss förändring av kunskapsdiskurser, främst mellan Lgy 70 och de två senare läroplanerna. Samtliga läroplaner innehåller till stor del ideologisk kunskap i allmänna delen, men Lgy 70 innehåller mer teoretisk kunskap jämfört med de andra läroplanerna. I Svenska har kursplanen gått från en teoretisk och praktisk inriktning till praktisk och ideologisk inriktning i Lpf 94 och Gy 2011. Kunskapsinnehållet har därmed även förändrats då sociala mål har blivit alltmer centrala i Lpf 94 och Gy 2011. Ytterligare ett resultat är att kunskapsbegreppet diskuteras i de två senare läroplanerna till skillnad från Lgy 70, men trots detta används inte typologin annat än i begreppsförklaring av de fyra F:n. Kunskap refereras därmed liknande i samtliga läroplaner, det vill säga genom kunskap och förmåga. Resultatet visar inte på att läroplanerna har blivit mer eller mindre kunskapsinriktade med åren utan att diskursen om vad kunskap innebär och uppfattningen om vad som är central kunskap i skolverksamheten har förändrats.<br>The purpose of the study is that through a qualitative and comparative textual analysis review knowledge discourses in the curricula Lgy 70, Lpf 94 and Gy 2011 to identify changes. The knowledge discourse have been divided as follows: theoretical, practical and ideological knowledge, and the focus is on the curriculum, the general part and curriculum for Swedish. In the center stands discourse theory, curriculum theory and epistemology in the interpretation of the results. The result shows that there has been a certain change of knowledge discourses, mainly between Lgy 70 and the latter two curricula. All curricula contain largely ideological knowledge in the general part, but Lgy 70 contains more theoretical knowledge compared to the other curricula. The curriculum for Swedish have shifted from a theoretical and practical approach to the practical and ideological orientation in Lpf 94 and Gy 2011. The knowledge content has consequently changed when social objectives have become increasingly central in Lpf 94 and Gy 2011. A further result is that the concept of knowledge is discussed in the latter two curricula unlike Lgy 70, but despite this is not the typology other than in conceptual explanation of the four F. Knowledge referenced thus similar in all curricula, through knowledge and ability. The results do not indicate that the curriculum has become more or less knowledge-oriented over the years but the discourse about what knowledge is and the perception of what is central knowledge in school activities has changed.
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Ankarbranth, Johannes. "Jämställdhet i det fördolda? : En feministisk pragmatisk diskursanalys av Lgy 70,Lpf 94 och Gy 2011." Thesis, Linnéuniversitetet, Institutionen för utbildningsvetenskap (UV), 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-39359.
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Uppsatsen syftar till att studera hur begreppet jämställdhet och dess diskurs i gymnasieskolan har förändrats i läroplanerna. Undersökningen går igenom Lgy 70, Lpf 94 och Gy 2011 och även de propositioner som ligger till grund av läroplanerna och analyserar dem utifrån ett feministiskt perspektiv. Detta för att få fram en fördjupad kunskap om hur jämställdhets sätts i uttryck i respektive läroplan. Uppsatsen metod består av en diskursanalys som grundar sig på Bacchis "What’s the problem represented to be?”-approach" modell som har anpassats för att svara mot uppsatsens syfte. Undersökningen visar att jämställdhetsarbetet har fått ett större utrymme över tid, men även att jämställdheten fortfarande aktivt ska arbetas för. Gällande representation för de olika könen visar undersökningen att kvinnor har fått en större möjlighet att påverka de senare läroplanerna, därmed har en kvinnlig synvinkel på läroplanen varit underrepresenterat i de första läroplanerna. Även om problematiken om ett icke jämställt samhälle har berörts i de tidigare läroplanerna, har inga konkreta förslag lämnats på hur denna problematik ska lösas. Skolan har alltid speglat arbetsmarknadens genom dess normer och antagande hur individen ska vara en god medborgare. Därför är det av stor vikt att skolan synliggör de genusmönster som minskar möjligheterna till jämställdhet i samhället. Slutsatsen är att skolans läroplaner har ändrats i syfte att öka jämställdhet mellan könen och för att motverka stereotypa antagande som kränker individen. Normen ska vara att respektera individen beslut, även om det bryter könsmönster och uppmuntra till val som inte enbart bekräftar stereotyper.
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Nilsson, Kristoffer. "Från Lpf 94 till Gy11 : En studie om implementeringen av en ny läroplan i idrott och hälsa." Thesis, Högskolan i Halmstad, Sektionen för lärarutbildning (LUT), 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-24897.
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Abstrakt Syftet med föreliggande undersökning är att mot bakgrund av tidigare forskning inom området, bidra med ytterligare förståelse för hur övergången mellan kursplaner kan upplevas av yrkesverksamma lärare och vilka praktiska konsekvenser det fått för undervisningen och genom detta försöka ge svar på studiens tre frågeställningar. Vad finns det för likheter/skillnader mellan kursplanerna Lpf 94 och Gy 11 när det gäller idrott och hälsa på gymnasiet? Har övergången till nya kursplanen förändrat synsättet på idrottsämnet utifrån lärarnas perspektiv? Hur har implementeringen av den nya kursplanen fungerat och hur har idrottsundervisningen i teori och praktik påverkats? De kvalitativa intervjuerna genomfördes med fem idrottslärare som alla hade erfarenhet av undervisning utifrån båda kursplanerna. Intervjuerna genomfördes med en semistrukturerad karaktär. Resultatet av kursplansjämförelsen och intervjuerna visade att Lpf 94 och Gy 11 är övervägande lika när det gäller innehåll men skiljer sig åt när det gäller struktur och uppbyggnad. Mycket är omformulerat och detta har ökat tydligheten jämfört med tidigare. Övergången till Gy 11 har inte märkbart påverkat lärarnas syn på idrottsämnet utan istället stärkt deras egna övertygelser om varför de valde att bli idrottslärare. Undersökningen visar att övergången till Gy 11 inte har fungerat fullt ut, lärarna har fått för lite tid och fortbildning för att sätta sig in i det nya systemet och detta påverkade både betygsättningen och undervisningen på ett negativt sätt. Dock visar resultatet att utvecklingen går åt rätt håll och att lärarna har hunnit ikapp det som de inte fick tid att göra vid övergången. Nyckelord: Läroplan, Kursplan, Betygssystem, Lpf 94, Gy 11, Implementering.
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Stenvall, Martin. "Förintelsen i gymnasieskolans läroböcker -En läroboksanalys om Förintelsens framställning i läroböcker för Lpf 94 och Lgy 11." Thesis, Örebro universitet, Institutionen för humaniora, utbildnings- och samhällsvetenskap, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:oru:diva-75123.
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The main purpose of this paper is to examine how the Holocaust is presented in textbooks, and if there are any differences in the textbooks since the Holocaust got more attention in the Swedish society. Six different textbooks, written for the two latest curriculums, are the empirical material for this study. They have been analyzed by using Ammerts theoretical perspective about four different ways of presenting the content in textbooks, and historical culture. The method for this study is a qualitative text analysis. The analysis shows that textbooks seem to have simplified presentations of the Holocaust. In the textbooks for the latest curriculum, the Holocaust is presented as a historical event that could be compared with other events in the past. Another difference is that authors for the newer textbooks presents the content by using values. The content about the Holocaust in the newer textbooks has also expanded. One possible reason could be that the authors would like to offer a more detailed explanation of the Holocaust. Another motive may be that generations that grew up after genocide has occurred see themselves as responsible to provide something similar to happen again. In relation to other countries, the historical culture in Swedish textbooks is different. It seems to be typical for Swedish textbooks to present how the Jews and other minorities were affected by the Holocaust. This could lead to make the students understand the value of the Holocaust, and preserve its place in the historical culture that exists in our society.
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Morgin, Nina. "Religionskunskapsundervisning : - en kunskapsresa, vars mål är lära för livet." Thesis, Högskolan i Halmstad, Sektionen för lärarutbildning (LUT), 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-14529.
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Uppsatsen ämnar genom litteraturstudium undersöka vilka läromedel som kan användas i Religionskunskap A och B, för att bidra till en mer levande och inspirerande undervisning för eleverna. Men även att se vilka aspekter en lärare behöver beakta, för att få en mer allsidig undervisning. Målet är att religionslärare ska kunna tillägna sig några av dessa förslag, för att ge deras elever en mer givande och inspirerande undervisning. Religionsundervisningen ska ses som en kunskapsresa, där det huvudsakliga , målet är att eleverna ska lära för livet. Att skapa en mer levande undervisning som stimulerar elevernas lärande, kräver att läraren utgår ifrån elevernas referensramar liksom möter dem utifrån deras egna villkor.
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Berg, Carl. "Litteraturens roll i andraspråksklassrummet : Intervjuer med två lärare om synen på litteraturundervisningen i andraspråksklassrummet." Thesis, Högskolan i Halmstad, Sektionen för lärarutbildning (LUT), 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-17133.
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Syftet med föreliggande studie är att utreda vilken roll litteratur har och hur lärare använder litteratur i ämnet svenska som andraspråk. Genom analys av kursplanerna i svenska och svenska som andraspråk på gymnasienivå har vissa generella slutsatser dragits. Statens syn på litteraturens syfte har ställts mot vad ledande forskning säger inom området. Genom en kvalitativ undersökning med halvstrukturerade intervjuer har informanternas resonemang kopplats samman med kursplaner och teorier gällande litteratur- och språkforskning. Resultatet visar att lärarna i undersökningen använder litteraturen bland annat för att skapa situationer som inbjuder till samtal i klassrummet.