High resolution computed tomography at the Ghent University: measuring, visualizing and analyzing the internal structure of objects with sub-micron precision.

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The role of positivity and causality in interactions involving higher spin

It is shown that the recently introduced positivity and causality preserving string-local quantum field theory (SLFT) resolves most No-Go situations in higher spin problems. This includes in particular the Velo–Zwanziger causality problem which turns out to be related in an interesting way to the solution of zero mass Weinberg–Witten issue. In contrast to the indefinite metric and ghosts of gauge theory, SLFT uses only positivity-respecting physical degrees of freedom. The result is a fully Lorentz-covariant and causal string field theory in which light- or space-like linear strings transform covariant under Lorentz transformation. The cooperation of causality and quantum positivity in the presence of interacting particles leads to remarkable conceptual changes. It turns out that the presence of H-selfinteractions in the Higgs model is not the result of SSB on a postulated Mexican hat potential, but solely the consequence of the implementation of positivity and causality. These principles (and not the imposed gauge symmetry) account also for the Lie-algebra structure of the leading contributions of selfinteracting vector mesons. Second order consistency of selfinteracting vector mesons in SLFT requires the presence of H-particles; this, and not SSB, is the raison d'être for H. The basic conceptual and calculational tool of SLFT is the S-matrix. Its string-independence is a powerful restriction which determines the form of interaction densities in terms of the model-defining particle content and plays a fundamental role in the construction of pl observables and sl interpolating fields

Nietzsche, immortality, singularity and eternal recurrence

Joan Copjec has shown that modernity is privy to a notion of immortality all its own – one that differs fundamentally from any counterpart entertained in Greek antiquity or the Christian Middle Ages. She points to Blumenberg and Lefort as thinkers who have construed this concept in its modern guise in different ways, and ultimately opts for Lefort's paradoxical understanding of immortality as the ‘transcending of time, within time’ before elaborating on a corresponding notion in Lacan's work. It can be shown that Nietzsche, too, provides a distinctly modern conception of ‘immortality’, articulated in relation to his notions of affirmation, singularity and eternal recurrence. In brief, this amounts to his claim that, to affirm even one single part or event in one's life entails affirming it in its entirety, and, in so doing – given the interconnectedness of events – affirming all that has ever existed. Moreover, once anything has existed, it is in a certain sense, for Nietzsche, necessary despite its temporal singularity. Therefore, to be able to rise to the task of affirming certain actions or experiences in one's own life, bestows on it not merely this kind of necessary singularity, but what he thought of as ‘eternal recurrence’ – the (ethical) affirmation of the desire to embrace one's own, and together with it, all of existence ‘eternally’, over and over. This, it is argued, may be understood as Nietzsche's distinctive contribution to a specifically modern notion of immortality: the ability of an individual to live in such a way that his or her singular ‘place’ in society is ensured, necessarily there, even after his or her death

New Constructions in Local Quantum Physics

Among several ideas which arose as consequences of modular localization there are two proposals which promise to be important for the classification and construction of QFTs. One is based on the observation that wedge-localized algebras may have particle-like generators with simple properties and the second one uses the structural simplification of wedge algebras in the holographic lightfront projection. Factorizable d=1+1 models permit to analyse the interplay between particle-like aspects and chiral field properties of lightfront holography. Pacs 11.10.-z, 11.55.-mComment: 21 pages, conference report, references adde

Lightfront Formalism versus Holography&Chiral Scanning

The limitations of the approach based on using fields restricted to the lightfront (Lightfront Quantization or p$\to \infty$ Frame Approach) which drive quantum fields towards canonical and ultimately free fields are well known. Here we propose a new concept which does not suffer from this limitation. It is based on a procedure which cannot be directly formulated in terms of pointlike fields but requires ``holographic'' manipulations of the algebras generated by those fields. We illustrate the new concepts in the setting of factorizable d=1+1 models and show that the known fact of absence of ultraviolet problems in those models (in the presence of higher than canonical dimensions) also passes to their holographic images. In higher spacetime dimensions d\TEXTsymbol{>}1+1 the holographic image lacks the transversal localizability; however this can be remedied by doing holography on d-2 additional lightfronts which share one lightray (Scanning by d-1 chiral conformal theories).Comment: 17 pages TCILatex, misprints in formulas of appendix correcte

Rotational particle separator: a new method for separating fine particles and mists from gases

An account is given of the patented technique of the rotational particle separator for separating solid and liquid particles of diameter 0.1 µm and larger from gases. Attention is focused on the working principle, fluid mechanical constraints, particle design, separation performance, power consumption, dimensions, filter cleaning and costs. Furthermore, an overview is given of current developments to introduce this technique in industrial dust removal, in electricity generation and in the consumer goods market. The article concludes with a summary of the feature which distinguish this technique from existing filtering methods