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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Lärare och kvalitetsdebatten : En studie av Dagens Nyheters debattsidor

Broberg, Magnus, Nordquist, Arvid January 2007 (has links)
I den här uppsatsen undersöks debattartiklar under åren 1997 till 2007 på Dagens Nyheters debattsidor. Intresset ligger vid att undersöka kvalitetsrelaterade skolfrågor och särskilt hur lärarprofessionen deltar i debatten. Som inspiration för behandling av materialet används Pierre Bourdieus ramverk med dess kapital- och fältbegrepp. Resultaten av undersökningen indikerar att lärarna har stort utrymme i debatten. Dessutom hörs statliga politiker i hög grad. Skolverket, akademiker och näringsliv deltar i betydligt mindre omfattning, men befinner sig inte på något sätt på marginalen. Kommunen däremot lyser med sin nästintill absoluta frånvaro. Den övergripande riktningen i debatten är att kvalitet nås genom en stärkt lärarprofession. De övergripande teman som finns i debatten utgår ifrån lärarprofessionens centrala betydelse.
32

Mannen och kvinnan på DN Debatt : - En studie av den jämställdhetsbild som framträder på Dagens NYheters debattsida

Karlsson, Stefan January 2006 (has links)
ABSTRACT Purpose/Aim: This essay aims to investigate what picture (obvious and hidden) of men and womens equality in our society that is to be found on DN Debatt. Material/Method: The material consists of 175 articles from DN Debatt during 2004. A content analysis and a rethoric analysis has then been used as a method of analysing the material. Main results: Men are much more represented on DN Debatt then women. The underlying picture of men and women that is presented sees men as being the ones who are in charge of all the important and “big” decisions and questions in our society. Women on the other hand are pictured as, although they have reached higher positions in society, the ones who to a high degree focus on closer and more socially important issues. The investigation has found much support of Yvonne Hirdmans theories of the gender system. Keywords: Dagens Nyheter, DN Debatt, Gender, Gender Images, Media
33

En chockerande studie om rubriksättning : Rubriksättningsproblematik i svensk media ur demokratisynpunkt

Hedman, Viktor January 2016 (has links)
Denna uppsats avser besvara huruvida rubriksättningen i media är bra eller dålig på att förmedla artiklarnas innehåll, vilket kan vara ett problem ur demokratisynpunkt, samt om nyheternas inträde på internet kan vara orsaken. Forskning av Daniel Dor visar på att en läsare generellt skannar rubriker snarare än att läsa tillhörande artikel, samtidigt som relevansteorin pekar på att det en risk att således också bilda sig kunskap utifrån dessa rubriker. Utifrån denna bakgrund analyseras resultaten med utgångspunkt i Robert A. Dahls demokratikriterium upplyst förståelse. Undersökningen använder sig av metoden innehållsanalys och fokuserar på rubriksättningen i Sveriges största dags- respektive kvällstidning, DN och Aftonbladet. De år som undersöks är 1995 och år 2015, vilket är innan de tryckta tidningarna också etablerade sig på internet respektive det år undersökningen genomförs. Kompletterande frågor ställs också till en anställd på DN som förklarar att rubriksättningsprocessen förändrats från 1995 till 2015. Resultatet av innehållsanalysen är att både DN och Aftonbladet har en betydande del, utifrån tillhörande artikel, informationsmässigt begränsade rubriker både år 1995 och 2015. Vidare argumenteras dessa resultat vara ett demokratiskt problem utifrån demokratikriteriet upplyst förståelse, eftersom de då riskerar att bilda sig utifrån artiklarna felaktiga åsikter.
34

Klimatkrisen och Dagens Nyheter : Hur rapporterar svensk nyhetsmedia om en av vår generations största utmaningar? / The climate crisis and Dagens Nyheter : How does swedish news media cover one of the greatest challenges of our generation?

Persson, Alexzandra, Villa, Johanna January 2021 (has links)
In October 2020 Peter Wolodarski, the editor-in-chief of the Swedish newspaper Dagens Nyheter (DN), announced that he wanted to improve the news coverage of the climate crisis. The aim of this study is to investigate whether DN has changed their way of reporting on the climate crisis through text and pictures within six months, and if so what those changes are. Framing theory is central in this study as it identifies the usage of generic and theme specific frames in DN’s articles. This is done by comparing all articles in September 2020 and March 2021 that contain the topic “climate crisis” published on their online service. The usage of pictures was also studied for additional context. In order to study this the methods qualitative text analysis and semiotic image analysis were used. To provide results the data then underwent a quantitative analysis as well as qualitative analysis.The findings of the study show that DN has shifted their usage of generic frames, meaning a change in which scale the climate crisis is portrayed, and an increased and widened usage of specific frames in their articles. However, the usage of pictures has not changed notably. In conclusion, does DN in fact seem to have changed their overall reporting on the climate crisis within the studied period. The study contribution is an added understanding of papers reporting on the clime crisis online as well as media’s usage of frames and how those can change in a relatively short period of time.
35

Modernismens lysande fasader : Belysningens påverkan på kulturhistoriska värden i 1960-talets höghus / Luminous facades in modernist architecture : The impact of lighting on cultural significance in 1960's high-rise buildings

Sandvik, Amanda January 2021 (has links)
Under 1900-talet har elektrisk belysning använts som en del i byggnaders utformning, med permanent fasadbelysning som en integrerad del i arkitekturen. När en ursprunglig fasadbelysning försvinner eller förändras, så försvinner också en del av möjligheten att uppleva byggnaden som den var avsedd. Den här undersökningen syftar därför till att lyfta belysningens påverkan på byggnaders kulturhistoriska värden. Genom fallstudier har två höghus i Stockholm uppförda under 1960-talet undersökts: femte Hötorgshuset och DN-huset. Båda byggnaderna har eller har haft en ursprunglig exteriör belysning. Genom en intervjustudie har olika professioners synsätt på belysning som en del av byggnaders uttryck studerats. Undersökningen visar att belysning kan ha stor påverkan på kulturhistoriska värden, inte minst på upplevelsevärdet. Det framkommer också att befintlig lagstiftning kan tillämpas för att skydda en ursprunglig belysning. Undersökningen argumenterar för att det finns vissa skillnader i olika yrkesgruppers synsätt, men att skillnaderna inte har någon större påverkan på bevarandet av belysning. / During the 20th century, electric lighting has been used as a part of the design of buildings, with permanent facade lighting as an integral part of the architecture. When an original facade lighting disappears of changes, part of the possibility to experience the building as it was intended is lost. This study therefore aims to highlight the impact of lighting on buildings’ cultural significance. Through case studies, two high-rise buildings in Stockholm built during the 1960s have been studied: the fifth Hötorgshuset and DN-huset. Both buildings have or have had an original exterior lighting. Through interviews, different professions’ view on lighting as part of the expression of buildings have been studied. This study concludes that lighting can have a great impact on cultural significance, not least in how lighting affects the perception of buildings. It also shows that existing legislation can be applied to protect original lighting. This study argues that there are some differences in the different professions’ views, but that these differences have no major impact on the preservation of lighting.
36

Comportamento em fadiga da liga Al-Li AA 2050 / Fatigue behavior of Al-Li alloy AA 2050

Bonazzi, Luís Henrique Camargo 10 July 2013 (has links)
As novas ligas de alumínio que contém lítio são atraentes devido à sua baixa densidade, alto módulo elástico, elevada resistência mecânica e por terem boa resistência à corrosão em comparação com ligas similares que não contém lítio. A degradação do material devido à fadiga e corrosão são os dois principais fatores que contribuem para o envelhecimento de uma aeronave. O objetivo deste trabalho é estudar a resistência à fadiga de uma nova liga de Al-Li, denominada de AA 2050-T84, considerando os estágios de nucleação e de propagação. No primeiro caso são avaliados o efeito da variação do concentrador de tensão (kt) e o efeito da razão de tensões (R), enquanto que no segundo caso são estudados os efeitos da direção de laminação e da razão de tensões (R) na taxa de propagação da trinca por fadiga. Para o estágio de iniciação é possível observar que quanto maior o valor de R, menor é a vida em fadiga. Para um R constante, o concentrador de tensão reduz significantemente a vida em fadiga. Considerando a vida de propagação de trinca por fadiga, observa-se que, independente da direção de laminação, quanto maior o valor de R, para um mesmo ΔK, maior foi a taxa de propagação de trinca. Para um mesmo R, o expoente m da equação de Paris é maior na direção TL indicando maior velocidade de crescimento de trinca. Independentemente da direção tomada, quanto maior o valor de R maior o valor de m. O modelo matemático utilizado previu muito bem o efeito de R na taxa de propagação de trinca. A liga AA 2050 apresenta resistência à fadiga similar ligas das famílias 2XXX e 7XXX e similar a da liga Al-Li AA 2198 T8. / The new Al-Li alloys are very attractive due to its low density, high elastic modulus, increased mechanical strength, as well as good corrosion resistance in comparison with similar alloys that don\'t contain lithium. The material\'s degradation due to fatigue and corrosion are the main factors of aircrafts aging, and it is quite important to take them in account to guarantee the aircraft structural integrity. The aim of this work is to study the fatigue strength of a new Al-Li alloy, denominated as AA 2050 T84, considering both nucleation and propagation fatigue lives. In the first case were evaluated the effect of the variation of the stress concentrator (kt) and the effect of the stress ratio (R), while in the propagation life were considered the effect of the rolling direction and the stress ratio (R). From the initiation life results, it is possible to observe that as higher was R, lower is fatigue life and that the intensity of the stress concentrator reduces fatigue life significantly, independent of the R value. The results from the propagation life shows that in both LT e TL directions and for a constant ΔK, higher R induces larger fatigue crack propagation rates. Considering a constant R, the TL direction presents a larger exponent m of Paris equation, which is an indicative of higher larger crack propagation rate. Also, larger R causes larger m, independently of the rolling direction. The mathematical model used was able to take in account the R effect on the crack propagation rate. Considering the more traditional Al alloys from 2XXX and 7XXX families, and the Ali-Li alloys AA 2198 T8, the AA 2050 presented a quite similar fatigue behavior.
37

Correlação de estrias de fadiga com espectro de cargas em liga de Al aeronáutica SAE-AMS 7475 T 7351. / Correlation of fatigue striation spacing to loading history in aeronautic Al alloy, AMS 7475 T7351.

Ruchert, Cassius Olivio Figueiredo Terra 29 August 2003 (has links)
Este trabalho discutiu a relação entre o espaçamento inter-estrias , isto é, a taxa de propagação da trinca microscópica SL (local) e SP (projetada) e a taxa de propagação macroscópica , da/dN, obtido após o ensaio de propagação de trinca por fadiga. Corpos de prova compacto C(T) foram extraídos na orientação LT do centro de uma placa laminada de liga de alumínio SAE-AMS 7475 T7351 onde posteriormente foram realizados ensaios de fadiga sob carga ou &#916K constantes, à temperatura ambiente de acordo com a Norma ASTM-E647 (1993). Para o ensaio sob carga constante foram obtidos os dados do estágio II e III da curva da/dN vs. &#916K. Para o ensaio de fadiga sob &#916K constante, quatro níveis de &#916K foram utilizados com taxas de crescimento de trinca variando entre 0,15 à 2,4 &#956m/ciclo. Adicionalmente foram realizados ensaios de tenacidade à fratura, KIC nas direções LT e TL conforme a Norma ASTM-E1820 (1999). A análise fratográfica por microscopia eletrônica de varredura foi conduzida no ensaio de fadiga a &#916K constante para determinar os espaçamentos inter-estrias. As taxas de propagação macroscópica e microscópica foram comparadas e boas correlações foram obtidas para um intervalo entre 0,1 a 1,0 &#956m/ciclo. Através da técnica proposta por Berkovitz (1995), o espectro de carregamento foi estimado através da técnica de parametrização do fator K e os resultados foram comparados ao espectro de carregamento real imposto pela máquina de ensaio. Utilizando o espaçamento inter-estrias local, SL, e para valores de &#916K menores que 23 MPam 1/2 (região de Paris), a estimativa de carregamento exibiu um erro menor que 15%. As vidas estimadas em propagação fornecidas pelas taxas microscópicas de propagação de trinca foram comparadas à vida real de propagação obtida a partir da taxa de propagação de trinca macroscópica e o erro absoluto entre ambos os valores foi menor que 15,7 %. Estes resultados sugerem que a vida em fadiga e o espectro de carga podem ser adequadamente estimados utilizando o espaçamento inter-estrias local, SL. / This work discusses the relationship between striation spacing, i.e. the microscopic crack propagation rate, SL (local) e SP (projected), as measured in post-mortem fractographic inspection of fatigue fractured surfaces, and the macroscopic crack propagation rate, da/dN, as monitored during fatigue crack growth tests. Compact tensile specimens C(T) were extracted in LT orientation from the core of a laminated plate of a SAE-AMS 7475-T7351 Al alloy and subsequently fatigue tested either at constant load or at constant &#916K, at room temperature, according to ASTM-E647. For constant amplitude loading fatigue tests, da/dN- &#916K data points were obtained for Regions II and III of crack growth curve. For constant &#916K fatigue tests, four &#916K levels were selected to give crack growth rates typically ranging from 0.15 to 2.4 &#956m/cycle. Additionally, KIC fracture toughness tests were performed in both LT and TL directions, according to ASTM E1820. SEM fractographic analysis was conducted on constant &#916K fatigue specimens, in order to determine striation spacing created during the fatigue test. Macro- and microscopic crack growth rates were compared and good correlation have been obtained for data within the range from 0,1 to 1,0 &#956m/ciclo. Using the technique proposed by Berkovitz, loading history was estimated by the K-factor parametrization and the results were compared to the true loading spectrum imposed by the testing machine. Using the local striation spacing SL and for &#916K values lower than 23 MPam 1/2 (Paris region), the estimated loading exhibits an error less than 15%. Propagation life estimated by local striation spacing (microscopic crack growth rate) was compared to the true propagation life obtained from macroscopic crack growth rate values and the absolute difference between them was less than 15,7%. These results suggest that both life and loading history can be adequately estimated using the local SL striation spacing values.
38

[en] INTERACTION BETWEEN MICROSTRUCTURAL ASPECTS AND INITIATION OF FATIGUE CRACKS IN STRUCTURAL STEELS / [pt] INTERAÇÃO ENTRE ASPECTOS MICROESTRUTURAIS E INICIAÇÃO DE TRINCAS DE FADIGA EM AÇOS ESTRUTURAIS

THIAGO ABREU PEREIRA PEIXOTO 08 April 2019 (has links)
[pt] O presente trabalho teve como objetivos avaliar a influência de heterogeneidades metalúrgicas sobre o limiar de propagação de trincas de fadiga e apresentar alternativas de materiais para a fabricação de eixos virabrequins de motores Diesel / gás natural de unidades geradoras de plantas termoelétricas, uma vez que tais componentes mecânicos fabricados com aço DIN 34CrNiMo6 vêm apresentando falhas por fadiga com baixo número de ciclos de carregamento. Corpos de prova foram usinados de aços SAE 4140, SAE 4340 e DIN 42CrMo4. Inicialmente, conduziram-se ensaios de tração para a determinação das propriedades mecânicas dos materiais. Ensaios de propagação de trincas de fadiga foram realizados em espécimes do tipo C(T) entalhados, submetidos a um carregamento cíclico. Pré-trincas de fadiga, com comprimentos variando entre 1,3 mm e 1,6 mm, foram induzidas nos corpos de prova de acordo com a norma ASTM E647. Em sequência, foram levantadas as curvas da/dN versus delta K dos materiais, com ênfase para a determinação da variação do fator de intensidade de tensão do limiar de propagação (delta Kth) de cada aço. Neste contexto, o aço SAE 4140 apresentou um valor de (delta Kth) superior aos demais, o que significa que suporta maiores tamanhos de trinca antes do início da propagação. Análises por técnicas de microscopia evidenciaram a presença de inclusões na região de propagação das trincas, dando origem a um caminho preferencial para o crescimento das mesmas. Os resultados destas análises indicaram a presença de uma menor quantidade de inclusões no aço SAE 4140, permitindo uma associação desta característica microestrutural com o valor do delta Kth do material. Desta maneira, no que se refere à iniciação de trincas de fadiga, o aço SAE 4140 apresenta-se como alternativa viável para substituição do aço 34CrNiMo6 na fabricação de eixos virabrequins para motores de usinas termoelétricas. / [en] The present study had as objectives to evaluate the influence of metallurgical heterogeneities on the fatigue cracking propagation threshold and to present alternative materials for the manufacture of crankshafts of diesel / natural gas engines of thermoelectric plants generating units, since such components mechanics manufactured with DIN 34CrNiMo6 steel has been presenting faults due to fatigue with a low number of loading cycles. Test specimens were machined from SAE 4140, SAE 4340 and DIN 42CrMo4 steels. Initially, tensile tests were conducted to determine the mechanical properties of the materials. Fatigue crack propagation tests were performed on C(T) specimens subjected to cyclic loading. Fatigue pre-cracks, with lengths ranging from 1.3 mm to 1.6 mm, were induced in the test specimens according to ASTM E647. In sequence, da/dN versus delta K curves of the materials were raised, with emphasis on the determination of the tensile strength factor of the propagation threshold (delta Kth) of each steel. In this context, the steel SAE 4140 presented a value of (delta Kth) superior to the others, which means to support larger crack sizes before the beginning of the propagation. Analysis by microscopy techniques evidenced the presence of inclusions in the region of crack propagation, giving rise to a preferential path for their growth. The results of these analyzes indicated the presence of a smaller number of inclusions in the steel SAE 4140, allowing an association of this microstructural characteristic with the value of the delta Kth of the material. In this way, with regard to the initiation of fatigue cracks, the SAE 4140 steel is presented as a viable alternative for the replacement of 34CrNiMo6 steel in the manufacture of crankshafts for motors of thermoelectric power plants.
39

Medium för makteliten : Hur yrkesrollerna och könsfördelningen förändrats på DN Debatt sedan 1985

Söderholm, Erik, Eliasson, Emilia January 2011 (has links)
Debattsidan i Dagens Nyheter har sedan 1980-talet varit en av Sveriges viktigaste opinionsbildare, och den fyller en värdefull funktion för fri åsiktsbildning i en väl fungerande demokrati. Denna studie fokuserar på hur debattsidan förändrats under de senaste 25 åren med utgångspunkt i kön (vem får oftast komma till tals på debattsidan, kvinnor eller män? – och hur har könsfördelningen utvecklats sedan 1980- talet?) och roll (exempelvis politiker, chefer och forskare). Vi har gjort en kvantitativ undersökning med början första helåret som DN Debatt hade en egen sida i tidningen, 1985, fram till 2010. Med hjälp av konstruerade veckor har sju dagar per år slumpmässigt valts ut. Resultaten visar att av våra författare (n = 498) är 75,3 procent av de undersökta författarna män, och 24,7 procent är kvinnor. Skillnaden mellan kvinnor och män minskar. Politiker är den största yrkesgruppen, och andelen politiker ökar ytterligare. Forskarna har legat på en relativt jämn nivå medan företagen publiceras på DN Debatt i allt högre grad. / The daily discussion feature ”DN Debatt” within the Swedish newspaper Dagens Nyheter has been one of the country’s most influencial opinion formers since the 1980’s. With the starting point in theories within media and communication, we hade studied this important institution with focus on how the gender distribution and the authors’ professional roles – for example politicians, researchers and journalists – have changed over the last 25 years. The results show that of our total population of authors (n = 498), 75,3 percent are men and 24,7 percent are women. The difference between men and women is decreasing. The professional roles that dominate our study are politicians, followed by researchers, journalists, CEOs and other representatives from companies, authorities and organizations. The ”common man” without some kind of established professional role is not published on DN Debatt.
40

Comportamento em fadiga da liga Al-Li AA 2050 / Fatigue behavior of Al-Li alloy AA 2050

Luís Henrique Camargo Bonazzi 10 July 2013 (has links)
As novas ligas de alumínio que contém lítio são atraentes devido à sua baixa densidade, alto módulo elástico, elevada resistência mecânica e por terem boa resistência à corrosão em comparação com ligas similares que não contém lítio. A degradação do material devido à fadiga e corrosão são os dois principais fatores que contribuem para o envelhecimento de uma aeronave. O objetivo deste trabalho é estudar a resistência à fadiga de uma nova liga de Al-Li, denominada de AA 2050-T84, considerando os estágios de nucleação e de propagação. No primeiro caso são avaliados o efeito da variação do concentrador de tensão (kt) e o efeito da razão de tensões (R), enquanto que no segundo caso são estudados os efeitos da direção de laminação e da razão de tensões (R) na taxa de propagação da trinca por fadiga. Para o estágio de iniciação é possível observar que quanto maior o valor de R, menor é a vida em fadiga. Para um R constante, o concentrador de tensão reduz significantemente a vida em fadiga. Considerando a vida de propagação de trinca por fadiga, observa-se que, independente da direção de laminação, quanto maior o valor de R, para um mesmo ΔK, maior foi a taxa de propagação de trinca. Para um mesmo R, o expoente m da equação de Paris é maior na direção TL indicando maior velocidade de crescimento de trinca. Independentemente da direção tomada, quanto maior o valor de R maior o valor de m. O modelo matemático utilizado previu muito bem o efeito de R na taxa de propagação de trinca. A liga AA 2050 apresenta resistência à fadiga similar ligas das famílias 2XXX e 7XXX e similar a da liga Al-Li AA 2198 T8. / The new Al-Li alloys are very attractive due to its low density, high elastic modulus, increased mechanical strength, as well as good corrosion resistance in comparison with similar alloys that don\'t contain lithium. The material\'s degradation due to fatigue and corrosion are the main factors of aircrafts aging, and it is quite important to take them in account to guarantee the aircraft structural integrity. The aim of this work is to study the fatigue strength of a new Al-Li alloy, denominated as AA 2050 T84, considering both nucleation and propagation fatigue lives. In the first case were evaluated the effect of the variation of the stress concentrator (kt) and the effect of the stress ratio (R), while in the propagation life were considered the effect of the rolling direction and the stress ratio (R). From the initiation life results, it is possible to observe that as higher was R, lower is fatigue life and that the intensity of the stress concentrator reduces fatigue life significantly, independent of the R value. The results from the propagation life shows that in both LT e TL directions and for a constant ΔK, higher R induces larger fatigue crack propagation rates. Considering a constant R, the TL direction presents a larger exponent m of Paris equation, which is an indicative of higher larger crack propagation rate. Also, larger R causes larger m, independently of the rolling direction. The mathematical model used was able to take in account the R effect on the crack propagation rate. Considering the more traditional Al alloys from 2XXX and 7XXX families, and the Ali-Li alloys AA 2198 T8, the AA 2050 presented a quite similar fatigue behavior.

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