A non-invasive node-based form finding approach with discretization-independent target configuration

Form finding is used to optimize the shape of a semi-finished product, i.e. the material configuration in a forming process. The geometry of the semi-finished product is adapted so that the computed spatial configuration corresponds to a prescribed target spatial configuration. Differences between these two configurations are iteratively minimized. The algorithm works non-invasively, thus there is a strict separation between the form update and the finite element (FE) forming simulation. This separation allows the use of arbitrary commercial FE-solvers. In particular, there is no need for a modification of the FE forming simulation, only the material configuration is iteratively updated. A new method is introduced to calculate the difference between the target and the computed spatial configuration. Thereby the target mesh is separated from the mesh for the FE forming simulation, which enables a more accurate and independent representation of the target configuration. In addition, the possibility of taking into account manufacturing constraints in the optimization process is presented. The procedure is illustrated for the example of the first stage of a novel two-stage sheet-bulk metal forming process

Radical Modernism in Derrida and Nietzsche

Der Beitrag diskutiert einen der späten Texte von Jacques Derrida. Der Text erlaubt es, Derrida als einen Denker der fortgeschrittenen Moderne zu interpretieren. Systematisch lässt sich die Moderne durch die Figur der Überwindung lesen, die sowohl im Sinne des Fortschritts als der Restauration verstanden werden kann. Derridas Frage lautet: Wie kann das Freiheitspotenzial der Überwindung beibehalten werden, ohne der in ihr liegenden Teleologie anheimzufallen? Eine Antwort ergibt sich durch den Begriff einer Zukunft, die als das schlechthin Unverfügbare in keiner Geschichte mehr situiert werden kann. Allerdings misslingt Derridas Versuch, diese unverfügbare Zukunft in Anlehnung an Kants praktische Philosophie normativ aufzuladen und als eine Form der Vernunft auszuweisen. Der Begriff bleibt leer, wie in Abgrenzung zu Nietzsche gezeigt werden kann. In Nietzsches Begriff des Übermenschen entwirft sich die Moderne auf eine Zukunft, die sie aus dem Zwang der Geschichte befreit. Nietzsche reflektiert die Figur der Überwindung, ohne sie, wie Derrida, zu entleeren.U prilogu se diskutira jedan od kasnijih tekstova Jacquesa Derride. Tekst dopušta interpretirati Derridu kao mislioca uznapredovale moderne. Sistematski je moguće modernu čitati kroz figuru prevladavanja, koja se može razumjeti u smislu napretka kao i restauracije. Derridino pitanje glasi: kako se može očuvati potencijal slobode prevladavanja, a da se ne podlegne teleologiji koja leži u njemu? Odgovor se nadaje u pojmu budućnosti, koja se kao ono jednostavno neovladljivo ne može više situirati ni u jednoj povijesti. No, propada Derridin pokušaj da tu neovladljivu budućnost normativno ispuni u osloncu na Kantovu praktičku filozofiju i legitimira je kao formu uma. Pojam ostaje prazan, kako se može pokazati u razgraničenju spram Nietzschea. U Nietzscheovu pojmu nadčovjeka nabacuje se moderna kao budućnost, koja je oslobađa prisile povijesti. Nietzsche reflektira figuru prevladavanja, a da je ne osiromašuje poput Derride.The paper discusses one of the later texts by Jacques Derrida. The text allows Derrida to be interpreted as a thinker of advanced modernity. Systematically it is possible to read modernity via the image of overcoming, which may be understood both in the sense of progress and restoration. The question Derrida asks is this: how can the potential of freedom to overcome be preserved without succumbing to teleology that informs it? The answer lies in the notion of future, which as the simply uncontrollable cannot be situated in any history. However, Derrida‘s attempt to normatively fill the uncontrollable future by relying on Kant‘s practical philosophy and legitimise it as a form of the mind fails. The notion remains empty, as can be shown by setting the boundary against Nietzsche. Nietzsche‘s notion of Übermensch hints at modernity as a future that liberates it from the pressure of history. Nietzsche reflects the figure of overcoming without impoverishing it the way Derrida does

Intracellular Accumulation of Collagen VII in Cultured Keratinocytes from a Patient with Dominant Dystrophic Epidermolysis Bullosa

Expression of collagen VII, a candidate molecule for dystrophic epidermolysis bullosa, was analyzed in cultured keratinocytes from a patient with generalized dominant dystrophic epidermolysis bullosa (DEBD) of the Pasini subtype. Double immunofluorescence revealed an increased intracellular staining of collagen VII that co-localized with protein disulfide isomerase, a marker of the rough endoplasmic reticulum. Ultrastructural analysis of cultured DEBD cells showed dilated cisternae of the rough endoplasmic reticulum and numerous residual bodies, both of which contained abundant collagen VII as detected by immunoelectron microscopy. Immunoblotting of keratinocyte extracts indicated an increased ratio of cell-associated versus secreted soluble collagen VII in DEBD cells. Collagen VII mRNA was of normal size in the DEBD cells, but present in excessive amounts. The data suggest a mutation in the collagen VII gene that leads to intracellular accumulation and degradation of this collagen, and thus to a reduced number of anchoring fibrils at the dermo-epidermal junction, and subsequently to blistering of the skin in this family

Removal of violations of the Master Ward Identity in perturbative QFT

We study the appearance of anomalies of the Master Ward Identity, which is a universal renormalization condition in perturbative QFT. The main insight of the present paper is that any violation of the Master Ward Identity can be expressed as a LOCAL interacting field; this is a version of the well-known Quantum Action Principle of Lowenstein and Lam. Proceeding in a proper field formalism by induction on the order in $\hbar$, this knowledge about the structure of possible anomalies as well as techniques of algebraic renormalization are used to remove possible anomalies by finite renormalizations. As an example the method is applied to prove the Ward identities of the O(N) scalar field model.Comment: 51 pages. v2: a few formulations improved, one reference added. v3: a few mistakes corrected and one additional reference. v4: version to be printed in Reviews in Mathematical Physic

Mental Models and Our Perception of Time

The creation of mental models is one of the key modes of human thinking and is how we interact with the world. However, our perception of time and how we experience time is directly linked to this sort of modeling behavior

A new method for the determination of plutonium and americium using high pressure microwave digestion and alpha-spectrometry or ICP-SMS

Plutonium and americium are radionuclides particularly difficult to measure in environmental samples because they are α-emitters and therefore necessitate a careful separation before any measurement, either using radiometric methods or ICP-SMS. Recent developments in extraction chromatography resins such as Eichrom® TRU and TEVA have resolved many of the analytical problems but drawbacks such as low recovery and spectral interferences still occasionally occur. Here, we report on the use of the new Eichrom® DGA resin in association with TEVA resin and high pressure microwave acid leaching for the sequential determination of plutonium and americium in environmental samples. The method results in average recoveries of 83±15% for plutonium and 73±22% for americium (n=60), and a less than 10% deviation from reference values of four IAEA reference materials and three samples from intercomparisons exercises. The method is also suitable for measuring 239Pu in water samples at the μBq/l level, if ICP-SMS is used for the measuremen

Continuous bunch-by-bunch spectroscopic investigation of the micro-bunching instability

Electron accelerators and synchrotrons can be operated to provide short emission pulses due to longitudinally compressed or sub-structured electron bunches. Above a threshold current, the high charge density leads to the micro-bunching instability and the formation of sub-structures on the bunch shape. These time-varying sub-structures on bunches of picoseconds-long duration lead to bursts of coherent synchrotron radiation in the terahertz frequency range. Therefore, the spectral information in this range contains valuable information about the bunch length, shape and sub-structures. Based on the KAPTURE readout system, a 4-channel single-shot THz spectrometer capable of recording 500 million spectra per second and streaming readout is presented. First measurements of time-resolved spectra are compared to simulation results of the Inovesa Vlasov-Fokker-Planck solver. The presented results lead to a better understanding of the bursting dynamics especially above the micro-bunching instability threshold.Comment: 12 pages, 11 figure

Relating on-shell and off-shell formalism in perturbative quantum field theory

In the on-shell formalism (mostly used in perturbative quantum field theory) the entries of the time ordered product T are on-shell fields (i.e. the basic fields satisfy the free field equations). With that, (multi)linearity of T is incompatible with the Action Ward identity. This can be circumvented by using the off-shell formalism in which the entries of T are off-shell fields. To relate on- and off-shell formalism correctly, a map sigma from on-shell fields to off-shell fields was introduced axiomatically by Duetsch and Fredenhagen. In that paper it was shown that, in the case of one real scalar field in N=4 dimensional Minkowski space, these axioms have a unique solution. However, this solution was given there only recursively. We solve this recurrence relation and give a fully explicit expression for sigma in the cases of the scalar, Dirac and gauge fields for arbitrary values of the dimension N.Comment: The case of gauge fields was added. 16 page

Erhebungen zum Einsatz von Glyphosat im deutschen Ackerbau

Glyphosat ist der weltweit meist verwendete Herbizidwirkstoff. Die Anwendungsgebiete von glyphosathaltigen Herbiziden decken eine Vielzahl von Kulturen und ackerbaulichen Situationen ab. Der Anwendungsumfang in Deutschland hat in den letzten zehn Jahren stark zugenommen. Daher sollte mit den Erhebungen ein Überblick über die tatsächlichen Einsatzgebiete erhalten werden. Im Frühjahr 2011 wurde eine Brief- und Online gestützte Umfrage unter deutschen landwirtschaftlichen Betrieben durchgeführt. 896 Fragebögen konnten ausgewertet werden. Die Studie erfasste ca. 250.000 ha LF und repräsentiert Betriebe aus ganz Deutschland. Die anhand der Betriebsangaben errechnete Applikationsfläche drückt den Anteil der Behandlungsfläche an der Anbaufläche aus. Große Flächenanteile von Raps (87,2 %), Körnerleguminosen (72,1 %) und Wintergerste (65,9 %) werden mit Glyphosat behandelt. Wesentliche Anwendungsgebiete sind in der Reihenfolge ihrer Bedeutung die Stoppelbehandlung, Vorsaatbehandlung und Sikkation. Stichwörter: Anwendungsgebiete, Herbizide, Sikkation, Stoppelbehandlung, Unkrautmanagement, Vorsaatbehandlung,A survey on the use of glyphosate in German arable farmingGlyphosate is the mostly used herbicide substance worldwide. Uses of glyphosate herbicides cover a wide range of crops and agronomical situations. During the last ten years, glyphosate use has increased in Germany. Thus, it is of specific interest to gather information on the current practice of its applications. In early 2011, a survey was carried out based on a postal and online inquiry of German farmers. The number of accessible valid answer sheets was 896. The study covered around 250000 ha of agricultural land, representing farms throughout Germany. The area of application was calculated (percentage), describing the proportion of application area from the cropping area of a specific crop. Large areas of oilseed rape (87.2 %), pulses (72.1 %) and winter barley (65.9 %) are treated with glyphosate. Predominating uses are (descending order): Stubble management, pre-sowing application and pre-harvest application (siccation). Keywords: Herbicides, herbicide uses, pre-sowing application, siccation, stubble management, weed managemen

Fast Mapping of Terahertz Bursting Thresholds and Characteristics at Synchrotron Light Sources

Dedicated optics with extremely short electron bunches enable synchrotron light sources to generate intense coherent THz radiation. The high degree of spatial compression in this so-called low-alpha optics entails a complex longitudinal dynamics of the electron bunches, which can be probed studying the fluctuations in the emitted terahertz radiation caused by the micro-bunching instability ("bursting"). This article presents a "quasi-instantaneous" method for measuring the bursting characteristics by simultaneously collecting and evaluating the information from all bunches in a multi-bunch fill, reducing the measurement time from hours to seconds. This speed-up allows systematic studies of the bursting characteristics for various accelerator settings within a single fill of the machine, enabling a comprehensive comparison of the measured bursting thresholds with theoretical predictions by the bunched-beam theory. This paper introduces the method and presents first results obtained at the ANKA synchrotron radiation facility.Comment: 7 pages, 7 figures, to be published in Physical Review Accelerators and Beam