361 research outputs found
Effect of laser temporal intensity skew on enhancing pair production in laser - electron-beam collisions
No full textRecent high-intensity laser experiments (Cole et al 2018 Phys. Rev. X 8 011020; Poder et al 2018 Phys. Rev. X 8 031004) have shown evidence of strong radiation reaction in the quantum regime. Experimental evidence of quantum effects on radiation reaction and electron-positron pair cascades has, however, proven challenging to obtain and crucially depends on maximising the quantum parameter of the electron (defined as the ratio of the electric field it feels in its rest frame to the Schwinger field). The quantum parameter can be suppressed as the electrons lose energy by radiation reaction as they traverse the initial rise in the laser intensity. As a result the shape of the intensity temporal envelope becomes important in enhancing quantum radiation reaction effects and pair cascades. Here we show that a realistic laser pulse with a faster rise time on the leading edge, achieved by skewing the temporal envelope, results in curtailing of pair yields as the peak power is reduced. We find a reduction in pair yields by orders of magnitude in contrast to only small reductions reported previously in large-scale particle-in-cell code simulations (Hojbota et al 2018 Plasma Phys. Control. Fusion 60 064004). Maximum pairs per electron are found in colliding 1.5 GeV electrons with a laser wakefield produced envelope 7.90 × 10-2 followed by a short 50 fs Gaussian envelope, 1.90 × 10-2, while it is reduced to 8.90 × 10-5, a factor of 100, for an asymmetric envelope
The SPD in the process of Europe's integration (1945-2009)
No full textPromotor: Prof. dr hab. Włodzimierz Bonusiak, 210 s.W pracy doktorskiej „SPD w procesie integracji Europy (1945-2009)” ukazano rolę jednej z największych partii Republiki Federalnej Niemiec w zachodzącym po II wojnie światowej procesie integracji Europy. Tezą główną pracy jest twierdzenie, że Socjaldemokratyczna Partia Niemiec aktywnie działała na rzecz pogłębiania jak i poszerzania Wspólnot Europejskich/Unii Europejskiej, chociaż zmieniały się jej koncepcje integracji. Ramy czasowe omawianego tematu obejmują lata 1945-2009, tj. okres od odradzania się życia partyjnego w strefach okupacyjnych do końca funkcjonowania Drugiej Wielkiej Koalicji (SPD/CDU/CSU) i wyborów do Parlamentu Europejskiego. Analizie poddano stosunek SPD do kolejnych etapów integracji, do prób integracji gospodarczej, politycznej, militarnej. Ukazano zaangażowanie SPD na rzecz rozszerzania i pogłębiania WE/UE. W pierwszym rozdziale pracy scharakteryzowano różne koncepcje integracji. W drugim - dokonano analizy czynników, które determinowały politykę zagraniczną SPD. Rozdział trzeci dotyczy ewolucji stanowiska SPD wobec pogłębiania integracji europejskiej, czwarty - podejściu tej partii do kwestii rozszerzania WE/UE o kolejne państwa europejskie. W rozdziale piątym przedstawiono sylwetki czołowych polityków SPD i ich wpływ na polityki europejską realizowaną przez partię i rząd niemiecki. W Zakończeniu zawarto zasadnicze wnioski.In the PhD thesis "The SPD in the process of Europe's integration (1945-2009)" the author demonstrates the role of the Social Democratic Party of Germany in the integration of Europe that took place after the Second World War. The main argument of the thesis is that SPD was actively involved in the development and enlargement of European Communities/the Europe's integration even though its understanding of integration has evolved. The timeframe of the discussion covers the years 1945-2009, i.e. the period since the re-emergence of party political life until the end of the second grand coalition (SPD/CDU/CSU) and elections to the European Parliament. The SPD's approach to subsequent stages of integration is analysed, including attempts at economic, political and military integration. The author demonstrates the involvement of the SPD in the enlargement and development of EC/EU. In chapter one, the author outlines different concepts of integration. In chapter two, the factors that determined the SPD's foreign policy are analysed. Chapter three focuses on the evolution of the SPD's position on enhancing European integration, chapter four – on SPD's approach towards the enlargement of the EC/EU. In chapter five the author presents the profiles of leading SPD politicians and describes their impact on the European policies. The summary contains the key conclusions
Grand Coalitions for Unpopular Reforms: Building a Cross-Party Consensus to Raise the Retirement Age
No full textThis article argues that an increase of the retirement age from 65 years to 67 or higher, which is the most unpopular pension reform measure, is politically feasible if the major parties build either a formal or an informal grand coalition. It argues further that institutional rules and agreed standards, especially the goals expressed in relation to pension policy, facilitate the formation of a grand coalition and increase the autonomy of governments vis-à-vis trade unions. Specifically, by restricting key policy instruments for responding to fiscal pressures, they lead political parties to consider the controversial option of raising the retirement age and to engage in a coordinative discourse about the necessity of this change and the limits of other reform options. This argument implies that the success of a retirement age reform does not depend on a negotiated agreement between a government and trade unions. By examining the agenda-setting and decisionmaking processes in Germany from the mid-1990s to 2007, this article shows that governments raise the retirement age only if they face constraints that rule out tax increases and benefit cuts and that they are able to enact even comprehensive retirement age reforms that increase not only the normal age but also the earliest eligibility age for both public and private pensions.welfare state, pension politics, retirement age, policy paradigms, institutional constraints, blame avoidance
Miniature tensile testing of SPD processed fine-grained aluminum
No full textManufacturing of ultrafine-grained (UFG) or nanocrystalline (NC) metals via a
single step top-down approach imposing severe plastic deformation (SPD) is one of the most
promising ways to achieve superior properties such as high strength and superplastic forming
capability. Nonetheless, the lack of relevant data on their post-SPD performance in different
test environments makes it difficult to fully understand their mechanical behavior. While
characterizing the tensile behavior, almost all of the previous reports are limited to the
discussion on the plastic performance of the material in terms of elongation to failure and
corresponding strength, with only a few studies discussing the effect of grain fragmentation on
work hardening response of the material. In the present work, a comprehensive analysis is
presented in terms of the uniform and post-necking mechanical behavior of the ultrafinegrained material. Commercially pure aluminum is subjected to high pressure torsion (HPT)
deformation with strains ranging from very low levels (γ ≈ 2.1) to values well in the saturation
regime (γ ≈ 25.1). When tested in uniaxial tension, the strength increases monotonously. The
uniform elongation improves with the imposed HPT strain, though remains lower than the
value of the initial material. Based on the slopes of the stress-strain curve, three distinct zones
are identified, i.e. uniform deformation, post-necking-1, and post-necking-2. With
accumulating SPD deformation, the material shows enhanced pre-necking strength and
ductility; while post-necking material fails early and at lower strength levels. The post-necking
response is observed to be highly microstructure dependent: a lower grain size augments the
resistance for micro-crack propagation and thus the ductility, however, once initiated, a crack
propagates much faster in fine-grained than in coarse-grained HPT processed material
History of the conferences on dynamic processes simulation SPD-1 — SPD-10 (1980-1998)
No full textW latach 70. ub. wieku następował rozwój metod symulacyjnych w badaniach naukowych układów dynamicznych i projektowaniu urządzeń. Stało się to dzięki rozwojowi techniki komputerowej i szerszym udostępnieniu komputerów w jednostkach badawczych oraz projektowych. Rozwój badań symulacyjnych następował tak samo szybko jak rozwój techniki komputerowej. Autor od końca lat 60. intensywnie rozwijał badania symulacyjne systemów automatyki i układów elektromechanicznych. Zaobserwował duże zainteresowanie symulowaniem układów dynamicznych w kraju, a organizując cykliczne konferencje pt. Metody Matematyczne w Elektrotechnice, postanowił rozpocząć cykl konferencji SPD. Konferencje SPD znalazły wielu zainteresowanych i w ciągu 19 lat, 10 tych konferencji zgromadziło ponad 1036 uczestników z różnych działów techniki, od elektryki po lotnictwo.In the 1970s, the development of simulation methods in scientific research of dynamical systems and design of devices took place. It happened thanks to the development of computer technology and the wider availability of computers in research and design units. The development of simulation research was as rapid as the development of computer technology. Since the end of the 1960s, the author has intensively developed simulation studies of automation and electromechanical systems. He noticed a great interest in simulating dynamical systems in the country, and by organizing cyclical conferences entitled Mathematical Methods in Electrical Engineering (MME), decided to start a series of SPD conferences. The SPD conferences found many interested, and in 19 years, 10 of these conferences gathered over 1000 participants from various technical fields, from electrics to aviation
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Women in German politics: still jobs for the boys?
No full textToday the proportion of German politicians who are female is at an all time high. This has largely been achieved via quotas and most of the main parties now operate some kind of quota system. But have quantitative improvements in female representation in been matched by qualitative improvements? This article seeks to answer this question by looking not only at the number of women in parliaments and other collective bodies, but also in the highest echelons of power. It outlines each party's policies regarding the promotion of women and the factors which enhance or hamper their impact. A brief comparison of female political representation in eastern and western Germany is also provided. The author argues that measures such as quotas have increased the number of female German politicians but still do not guarantee them equal access to positions of real power. Furthermore, the incorporation of pro-equality principles into party statutes has not automatically led to their assimilation into party cultures, especially in the case of well-established parties which only recently addressed the gender imbalance in their ranks
SPD from the Socio-Cultural Approach to Populism
No full textThe thesis analyses the political movement Freedom and Direct Democracy (SPD) in relation to the socio-cultural approach to populism. For this purpose, it uses the characteristic features of the socio-cultural approach defined mainly by P. Ostiguy and other scholars. The author analyses the external communication of Tomio Okamura, the leader of the political movement Freedom and Direct Democracy (SPD), through the podcast Mezi dvěma světy (<Between two worlds=), available on the streaming platforms YouTube and Spotify. In the first part of the thesis, different approaches to populism were presented: ideational, strategic and socio-cultural. The main element of the socio-cultural approach is in particular the role of the charismatic leader. The second part presents the political movement Freedom and Direct Democracy (SPD), followed by the application of the features of the socio-cultural approach to populism through the analysis of the podcast
Biografieanalyse zweier Generationen von SPD-Spitzenpolitikern aus der Perspektive der Habitus-Feld-Analyse
No full textThis article features results of a study in which the author was inspired by Pierre Bourdieu\u27s Habitus-/Field-method to examine biographies of leading SPD-politicians of the postwar period. After the era Schröder (from 2005 onwards), members of this "great-grandchild-generation", who experienced National Socialism, the Second World War and the postwar period at a very young age, shaped SPD politics significantly at the national level. The theoretical and methodological basics of the analysis are outlined and used to present selected results that shed light on the question whether the representation of SPD members has changed
SPD from the Socio-Cultural Approach to Populism
No full textTato práce analyzuje politické hnutí Svoboda a přímá demokracie (SPD) ve vztahu k socio-kulturnímu přístupu k populismu. Využívá pro to charakteristické rysy socio-kulturního přístupu, které definoval především P. Ostiguy a další odborníci. Autorka analyzuje vnější komunikaci Tomia Okamury, lídra hnutí Svobody a přímé demokracie (SPD), prostřednictvím podcastu Mezi dvěma světy dostupného na streamovacích platformách YouTube a Spotify. V první části práce byly přiblíženy různé přístupy k populismu: ideační, strategický a socio-kulturní. Hlavním prvkem socio-kulturního přístupu je zejména role charismatického lídra. Druhá část přibližuje politické hnutí Svoboda a přímá demokracie (SPD), na což navazuje aplikace znaků socio-kulturního přístupu k populismu prostřednictvím analýzy podcastu.The thesis analyses the political movement Freedom and Direct Democracy (SPD) in relation to the socio-cultural approach to populism. For this purpose, it uses the characteristic features of the socio-cultural approach defined mainly by P. Ostiguy and other scholars. The author analyses the external communication of Tomio Okamura, the leader of the political movement Freedom and Direct Democracy (SPD), through the podcast Mezi dvěma světy (<Between two worlds=), available on the streaming platforms YouTube and Spotify. In the first part of the thesis, different approaches to populism were presented: ideational, strategic and socio-cultural. The main element of the socio-cultural approach is in particular the role of the charismatic leader. The second part presents the political movement Freedom and Direct Democracy (SPD), followed by the application of the features of the socio-cultural approach to populism through the analysis of the podcast.Institute of Political ScienceÚstav politologieFilozofická fakultaFaculty of Art
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