Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / This study describes two families of transition metal oxides (OMT). Because of its potential and diversity of physical properties, the OMT are promising candidates for technological applications. In contrast, physically understand the complex relationship of these properties has been the main challenge of the research in this area. One of the families that was studied in this work are composed of Ruddlesden Popper type (RP), nickel base, of formula Lan+1NinO3n+1. The RP oxides have become more popular in the decade of 80, when it was discovered that a compound of this family, the La2CuO4− can become superconductive when appropriately doped. Another important property associated with the RP oxides is the colossal magnetoresistance, observed in the manganese-based compounds, such as Ca3−xLaxMn2O7. Another family of OMT studied in this work are the compounds garnets type of formula R3Fe5O12 (Where R is rare earth element or Y). This family is known to be rich in physical properties, especially magnetic, The magnetism of these compounds is associated mainly with the ferrimagnetic interaction between ions of Fe3+ in octahedral and tetrahedral coordination. The magnetic moment resulting from interactions of the Fe3+ can orient yourself antiferromagnetic with the network ion R, if it is a rare earth magnetic. A property that has been strongly investigated in compounds garnets is the magnetocaloric effect (EMC). This effect, which tracks the magnetic transitions, is more relevant and meaningful in compounds that are promising candidates for use in magnetic refrigeration. To investigate some of the physical properties of these systems were synthesized compounds (Dy, Y)3Fe3Al2O12 and Lan+1(Ni1−xZnx)nO3n+1 (n = 1, 2, 3 e 0 ≤ x ≤ 0.5). To synthesize the samples used two methods, combustion reaction (RC) and coprecipitation (CP). Both methods have proven effective for obtaining samples with the desired phase. The technique of X-ray diffraction, together with the Rieteveld refinement method was used to extract crystallographic information of the synthesized compounds. Morphological information of samples, such as size, shape and distribution of particles were investigated by the technique of scanning electron microscopy. The micrographs show that regardless of the synthesis method, the particle shape is not well defined and the size distribution is inhomogeneous. Some samples of garnets type, synthesized by CP, have particle size in the nanoscale. Some compounds were characterized by electrical resistivity measurements as a function of temperature, where it was found that the series La2Ni1−xZnxO4 it has semiconducting properties in the temperature range from 10 KM to 300 K. The magnetic properties were investigated by magnetization measurements as a function of temperature and magnetic field, where it was found that the magnetism of both systems is affected by the inclusion of non-magnetic ions. EMC was investigated in two samples of garnets type, the data were obtained from the magnetization as a function of temperature and it was found that the aluminum insert in the structure, replacing the iron, decreased temperature magnetic transition, but also reduced the intensity EMC. / Neste trabalho estudamos duas fam´ılias de ´oxidos de metais de transi¸c˜ao (OMT). Devido ao seu potencial e diversidade de propriedades f´ısicas, os OMT s˜ao promissores candidatos a aplica¸c˜oes tecnol´ogicas. Em contrapartida, compreender fisicamente a complexa rela¸c˜ao destas propriedades tem sido o principal desafio das pesquisas desta ´area.Uma das fam´ılias que estudamos neste trabalho s˜ao compostos do tipo Ruddlesden Popper (RP) a base de n´ıquel, com f´ormula Lan+1NinO3n+1. Os ´oxidos RP tornaram-se mais conhecidos na d´ecada de 80, quando foi descoberto que um composto desta fam´ılia, o La2CuO4− , pode se tornar supercondutor quando apropriadamente dopado. Outra importante propriedade associada com os ´oxidos RP ´e a magnetorresistˆencia colossal, observada em compostos a base de manganˆes, a exemplo do Ca3−xLaxMn2O7. Outra fam´ılia de OMT estudada neste trabalho s˜ao compostos tipo garnets de f´ormula R3Fe5O12 (onde R ´e um elemento terra rara ou Y). Essa fam´ılia ´e conhecida por sua riqueza de propriedades f´ısicas, especialmente magn´eticas. O magnetismo destes compostos est´a associado, principalmente, com a intera¸c˜ao ferrimagn´etica entre os ´ıons de Fe3+ em coordena ¸c˜ao octa´edrica e tetra´edrica. O momento magn´etico resultante das intera¸c˜oes do Fe3+ pode se orientar antiferromagneticamente com a rede do ´ıon R, se ele for um terra rara magn´etico. Uma propriedade que vem sendo investigada nos compostos garnets ´e o efeito magnetocal´orico (EMC). Este efeito, que acompanha as transi¸c˜oes magn´eticas, ´e mais relevante e significativo em compostos que s˜ao promissores candidatos a aplica¸c˜ao em refrigera¸c˜ao magn´etica. Para investigar algumas das propriedades f´ısicas destes sistemas, foram sintetizados compostos (Dy, Y)3Fe3Al2O12 e Lan+1(Ni1−xZnx)nO3n+1 (n = 1, 2, 3 e 0 ≤ x ≤ 0.5). Para a s´ıntese das amostras foram utilizados dois m´etodos, rea¸c˜ao de combust˜ao (RC) e coprecipita¸c˜ao (CP). A t´ecnica de difra¸c˜ao de raios X, aliada ao m´etodo de refinamento Rieteveld, foi utilizada para extrair informa¸c˜oes cristalogr´aficas dos compostos sintetizados. Informa¸c˜oes sobre morfologia das amostras, como tamanho, forma e distribui¸c˜ao das part´ıculas, foram investigadas pela t´ecnica de microscopia eletrˆonica de varredura. As micrografias revelam que independentemente do m´etodo de s´ıntese a forma das part´ıculas n˜ao ´e bem definida e a distribui¸c˜ao de tamanhos n˜ao ´e homogˆenea. Algumas amostras do tipo garnets, sintetizadas por CP, tˆem part´ıculas de tamanho na escala nanom´etrica. Alguns compostos foram caracterizados por medidas de resistividade el´etrica em fun¸c˜ao da temperatura, em que se verificou que a s´erie La2Ni1−xZnxO4 tem propriedades semicondutoras no intervalo t´ermico de 10 K a 300 K. As propriedades magn´eticas foram investigadas por medidas de magnetiza¸c˜ao em fun¸c˜ao da temperatura e do campo magn´etico, em que se verificou que o magnetismo de ambos os sistemas ´e afetado pela inser¸c˜ao dos ´ıons n˜ao magn´eticos. O EMC foi investigado em duas amostras do tipo garnets, os dados foram obtidos das medidas de magnetiza¸c˜ao em fun¸c˜ao da temperatura e se verificou que a inser¸c˜ao do alum´ınio na estrutura, em substitui¸c˜ao ao ferro, causou uma diminui¸c˜ao na temperatura de transi¸c˜ao magn´etica, por´em tamb´em reduziu a intensidade do EMC.

Made available in DSpace on 2014-07-29T15:00:23Z (GMT). No. of bitstreams: 1 Dissertacao Stenio G de Oliveira.pdf: 1227425 bytes, checksum: 972ee38681a58bf0f9ccea1e721ad8e0 (MD5) Previous issue date: 2011-09-16 / A importância e o uso da história e filosofia das Ciências no ensino têm sido defendidos, de maneira enfática, por diferentes autores visando uma educação científica de qualidade. Da mesma forma, evidentemente com diferentes argumentos, outros autores são contrários ao seu uso. Colocando-me do lado dos defensores deste uso, neste trabalho defende-se que o ensino das Ciências e sua aprendizagem precisam ser acompanhados pelo estudo sobre a natureza da Ciência, haja vista que tanto a história como a filosofia das Ciências são importantes para pesquisadores e para professores. O presente estudo busca analisar as visões de dois filósofos da Ciência, Thomas Kuhn e Paul Feyerabend, que apontam importantes perspectivas para a discussão sobre o desenvolvimento científico. Ambos estudam a Revolução Copernicana, e verificam que o desenvolvimento científico nem sempre está condicionado a fatores racionais, ou metodológicos, entendidos como um conjunto de regras a ser seguido ou um conjunto de passos que norteiam a atividade científica. O método utilizado nesta dissertação foi de uma pesquisa bibliográfica, com foco principal na leitura dos livros destes dois autores. Isto é feito em duas partes: a primeira através de uma revisão de suas visões de Ciência e a segunda é uma tentativa pessoal de recortar suas descrições e análises sobre a Revolução Copernicana. Estes recortes têm a intenção de ressaltar, tendo por base os trabalhos de astrônomos como Copérnico e outros posteriores a ele, características, passagens ou influências subjetivas dentro da atividade científica. Subjetividade para Kuhn, irracionalidade para Feyerabend. O que se busca neste trabalho é oferecer subsídios para a discussão clássica de nossa visão de Ciência como sendo sempre racional , metodologicamente rígida, e evidenciar elementos de subjetividades/irracionalidades(?) na atividade científica que devem ser trabalhados e discutidos no ensino de Ciências.

Orientador: Octavio Ianni / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Filosofia e Ciencias Humanas / Made available in DSpace on 2018-07-20T15:15:26Z (GMT). No. of bitstreams: 1 Paiva_LuizHenriquedaSilvade_M.pdf: 2056577 bytes, checksum: b15662d79199e801ca7163d05a351561 (MD5) Previous issue date: 1995 / Resumo: Não informado / Abstract: Not informed / Mestrado / Mestre em Ciências Sociais

Orientador : Michael Wrigley / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Filosofia e Ciencias Humanas / Made available in DSpace on 2018-07-17T08:20:04Z (GMT). No. of bitstreams: 1 Caponi_GustavoAndres_D.pdf: 16497294 bytes, checksum: 676421e07ab16dd82bb2249aead86ebc (MD5) Previous issue date: 1992 / Resumo: Não informado / Abstract: Not informed. / Doutorado / Doutor em Lógica e Filosofia da Ciência

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第22466号 / 工博第4727号 / 新制||工||1738(附属図書館) / 京都大学大学院工学研究科分子工学専攻 / (主査)教授 田中 庸裕, 教授 陰山 洋, 教授 佐藤 徹 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

Tesis para optar al grado de Magister en Filosofía / La literatura en filosofía de las ciencias frecuentemente identifica a Sir Karl Popper como un filósofo anti-relativista y a Thomas Kuhn como uno relativista. No obstante, y en especial respecto del estadounidense, estas identificaciones no están exentas de problemas. En el presente estudio se desarrolla una evaluación comparativa de los modelos de las ciencias de ambos autores con el propósito de determinar cuál es su posición exacta respecto del relativismo epistemológico en las ciencias. En tanto ambos modelos difieren sustantivamente en su terminología y enfoques, la metodología a seguir será contraponerlos con una postura que provee una serie de tesis bien determinadas con las cuales se neutraliza eficientemente el relativismo en las ciencias, a saber, el realismo científico. Se determinará si los modelos en cuestión siguen las tesis expuestas por este realismo para neutralizar el relativismo o si postulan maneras alternativas de conseguir el mismo fin. La finalización de esta evaluación arrojará conclusiones que permiten matizar las identificaciones que provee la literatura. En primer lugar, se muestra que el modelo de Popper puede ser considerado como anti-relativista, pero uno de carácter ineficaz. Dicho de otro modo, uno que no provee razones para defender que la ciencia no sea una empresa relativista. Por otro lado, se muestra que el modelo de Kuhn debe ser considerado uno relativista moderado. En otras palabras, un tipo de relativismo que al menos provee razones para negar que la ciencia sea una empresa relativista radical. / Diciembre 2021

In this essay I evaluate the legality of Karl Popper’s criticism against psychoanalysis, regarding this theory of Freud’s being pseudoscientific. Popper’s criticism is based on his theory of demarcation in which he states that an empirical theory must be possible to test by observations in order to be, as most important is, hypothetically possible to falsify based on other empirical statements – often in the form of new found facts that contradict the original statement/theory. In purpose of assessing Popper’s criticism I perform a modified idea analysis, based on a book by Evert Vedung (1977). By referring both to Popper and to spokespersons of psychoanalysis I structure the arguments pro and contra Popper’s criticism, in order to then weigh these arguments against each other. My main conclusion is that psychoanalysis, regardless of Popper’s criticism, is in fact an empirical theory since it can be internally validated based on the observations made by a psychoanalyst. But according to the theory of demarcation psychoanalysis can not be tested based on observations, probably because Popper by ”observations” meant only those that can be made and validated by independent scientists.

The aim of this paper is to examine the Islamic state’s information operations and how they target three different domains of influence. Domains consisting of the field of information, the physical world and human cognition, as described by the Swedish armed forces. Previous studies showcase that the ISIS information approach is mainly characterized by utilizing the internet and distributing propaganda. All in order to gain support and legitimize their newly founded caliphate. However, studies does not show how these operations target different domains in order to influence the recipients. The lack of insight in how this phenomenon occurs is also evident in contemporary military theory. An insight that this study aim to provide. The theoretical premises used for the analysis are What is information warfare? by Martin C. Libicki and Karl Popper’s Objective knowledge. The designated method to examine the empirical data was a qualitative text analysis. The result of the analysis indicates that ISIS target all three previously mentioned domains by psychological operations. ISIS also target the field of information using cyber operations.

Solid oxide fuel cells are used as stationary power plants for electricity production. Despite having a very high efficiency of 90% they haven’t gained a world-wide commercial usage, due to their very high operating temperatures, and high production cost. However, there is a lot of ongoing research with the aim of developing intermediate-temperature solid oxide fuel cells (IT-SOFCs) that could operate at temperatures below 800°C. Cathodes are the most studied components of IT-SOFCs, since decreasing operating temperature results in slow oxygen reduction reaction(ORR) kinetics and large polarization losses. Perovskite related metal oxides have become very popular materials that could make suitable cathodes for IT-SOFCs. In this work an evaluation of several materials belonging to three different material groups have been studied: single layer perovskites, with a general formula of ABO3, double layer perovskites, with a general formula of AA’B2O6 and Ruddlesden-Popper phase, with a general formula of An+1BnO3n+1. Power generating capabilities of those materials have been studied on an electrolyte supported cell, cathode/LSGM9182/Ni-Fe. IR drop and overpotential of the cathode was measured and activation energy of the ORR for each material has been calculated. The double layer perovskite cobaltites offer a significant drop in overpotential, increase in conductivity compared to their single layer counterpart, while being able to generate significant amount of power. Ruddlesden-Popper phase materials offer the lowest activation energy values amongst the researched materials, but offer limited power generation values in the setup they were tested. Both of double layer perovskites and Ruddlesden-Popper based materials have opportunities for their performance to be improved. / Fastoxidbränsleceller används som stationära kraftverk för elproduktion. Trots att de har en mycket hög effektivitet på 90% har de inte fått en världsomspännande kommersiell användning på grund av deras mycket höga driftstemperaturer och hög produktionskostnad. Det är emellertid mycket pågående forskning med sikte på att utveckla intermediär temperatur fastoxidbränsleceller (IT-SOFC) som kan fungera vid temperaturer under 800 ° C. Katod är de mest studerade komponenterna i IT-SOFC, eftersom minskad driftstemperatur resulterar i kinetik med långsam syrereduktion (ORR) och stora polarisationsförluster. Perovskite-relaterade metalloxider har blivit mycket populära material som kan göra lämpliga katoder för IT-SOFC. I detta arbete har en utvärdering av flera material som hör till tre olika materialgrupper studerats: singelskikt perovskiter, med en generell formel för ABO3, dubbelskikt perovskiter, med en generell formel av AA'B2O6 och Ruddlesden-Popper-fasen med en allmän formel för An + 1BnO3n + 1. Effektgenereringskapaciteten hos dessa material har studerats på en elektrolytbärbar cell, katod / LSGM9182 / Ni-Fe. IR-droppe och överpotential hos katoden mättes och aktiveringsenergin för ORR för varje material har beräknats. Dubbelskiktet perovskit koboltiter ger en signifikant minskning av överpotentialen, ökad ledningsförmåga jämfört med deras enkelskikt motpart, samtidigt som man kan generera betydande mängden kraft. Ruddlesden-Popper-fasmaterial erbjuder de lägsta aktiveringsenergivärdena bland de undersökta materialen, men erbjuder begränsade kraftproduktionsvärden i den inställning de testades. Både av dubbelskiktet perovskiter och Ruddlesden-Popper-baserade material har möjligheter att förbättra deras prestanda.

<p>Toward the end of the nineteenth century, Ernst Mach expressed his worries about obscurities and metaphysical elements in scientific knowledge, and consequently contributed to the development of a Viennese tradition. Later on, Vienna Circle further extended Mach's ideas and led to the development of the logical positivist movement. Among the main tenets of this movement is the view that scientific theories are to be reduced to an empirical base capable of conclusive verification. But scientific theories are usually based on unverified and occasionally unverifiable hypotheses and principles. Thus, once this is realized, positivism in spite of itself will contribute to the development of scepticism about scientific knowledge.</p> <p>In reaction to the verificationism, however, Karl Popper developed his thesis of falsificationism or fallibilism; but this principle also leads to scepticism at least about certainty claims, with far reaching consequences. This chain of events leads to the development of Paul Feyerabend's epistemological anarchisma a rejection of all rules and methods in science in an attempt to reduce science to the level of irrationality and mythology.</p> <p>Against the negativist conclusions of these positions about science, the integrity of scientific knowledge is defended in this thesis. It is shown how scientific knowledge can be defended against scepticism of the type to which verificationism tends: this is done by examining one recent and rigorous sceptical position which undermines not only certainty and rationality of knowledge claims, but the very possibility of knowledge. By examining Popper's fallibilism, it is shown that science can also be defended against the negativist conclusions of fallibilism. Similarly, it is shown that Feyerabend's epistemological anarchism cannot either undermine scientific knowledge.</p> <p>These negativist positions, though they have received strong criticisms in some quarters, yet have not been examined all together, from the standpoint of their impact on the integrity of scientific knowledge. This task is undertaken in this thesis; we thus arrive at a positive and correct evaluation of scientific knowledge in the context of contemporary negativist epistemological trends. It has been shown that in spite of all the negativist arguments of the above positions, we can obtain certainty, justification, and truth in science, and thus we can obtain knowledge. But my rejection of negativism in science does not entail, and should not be construed as an advocacy of a return to, positivism.</p> / Thesis / Doctor of Philosophy (PhD)