For the first time since 1871, the International Art History Congress was held on invitation at a museum. From the 15th to the 20th of July, 2012 the “Object” has been the focus of 21 sections and up to 400 lectures. The aim of the Congress was to discuss and redefine the object’s role and meaning as a basis and subject matter of art history.

Today’s media not only facilitates worldwide communication, but also the “virtualisation” of art history. What consequences does this have for the object itself? What chance and what risks ensue in the virtualisation of our profession? In addition to the virtualisation, we are also experiencing the extraordinary effect of the object itself. Long queues of visitors form to view one piece of art. During war, artworks are protected by international conventions, in particular the amount of damage they are exposed to. Ruined world-heritage sites, and also artwork that is taken hostage, belong to daily politics (looted art).

Up until now, art history has, notably in Europe, had European artwork in focus. Non-European art was often measured with other criterion. Methodical comparative research of artwork from different lands is sensible. How can such research be conducted in the future? Is there a line between a “High Culture”, in which art history is interested, and “Folk Culture”, toward which ethnology strives?

The sections of the 33rd International Art History Congress are structured around the questions in the dealings and the roles of the object, not on categories, epochs or continents. The fundamental approach of art history research of an object is not dependent on category, age or land of origin. We want, therefore, to compare and correlate similar questions and developments in cooperation with the different cultures, and determine the role of the object in the future of art history.

Taylor–Couette flow with independently rotating inner ($i$) and outer ($o$) cylinders is explored numerically and experimentally to determine the effects of the radius ratio $\eta $ on the system response. Numerical simulations reach Reynolds numbers of up to $\mathit{Re}_i=9.5\times 10^3$ and $\mathit{Re}_o=5\times 10^3$, corresponding to Taylor numbers of up to $\mathit{Ta}=10^8$ for four different radius ratios $\eta =r_i/r_o$ between 0.5 and 0.909. The experiments, performed in the Twente Turbulent Taylor–Couette ($\mathrm{T^3C}$) set-up, reach Reynolds numbers of up to $\mathit{Re}_i=2\times 10^6$ and $\mathit{Re}_o=1.5\times 10^6$, corresponding to $\mathit{Ta}=5\times 10^{12}$ for $\eta =0.714\mbox{--}0.909$. Effective scaling laws for the torque $J^{\omega }(\mathit{Ta})$ are found, which for sufficiently large driving $\mathit{Ta}$ are independent of the radius ratio $\eta $. As previously reported for $\eta =0.714$, optimum transport at a non-zero Rossby number $\mathit{Ro}=r_i |\omega _i-\omega _o |/[2(r_o-r_i)\omega _o]$ is found in both experiments and numerics. Here $\mathit{Ro}_{opt}$ is found to depend on the radius ratio and the driving of the system. At a driving in the range between $\mathit{Ta}\sim 3\times 10^{8}$ and $\mathit{Ta}\sim 10^{10}$, $\mathit{Ro}_{opt}$ saturates to an asymptotic $\eta $-dependent value. Theoretical predictions for the asymptotic value of $\mathit{Ro}_{opt}$ are compared to the experimental results, and found to differ notably. Furthermore, the local angular velocity profiles from experiments and numerics are compared, and a link between a flat bulk profile and optimum transport for all radius ratios is reported.

Strongly turbulent Taylor–Couette flow with independently rotating inner and outer cylinders with a radius ratio of is experimentally studied. From global torque measurements, we analyse the dimensionless angular velocity flux as a function of the Taylor number and the angular velocity ratio in the large-Taylor-number regime and well off the inviscid stability borders (Rayleigh lines) for co-rotation and for counter-rotation. We analyse the data with the common power-law ansatz for the dimensionless angular velocity transport flux , with an amplitude and an exponent . The data are consistent with one effective exponent for all , but we discuss a possible dependence in the co- and weakly counter-rotating regimes. The amplitude of the angular velocity flux is measured to be maximal at slight counter-rotation, namely at an angular velocity ratio of , i.e. along the line . This value is theoretically interpreted as the result of a competition between the destabilizing inner cylinder rotation and the stabilizing but shear-enhancing outer cylinder counter-rotation. With the help of laser Doppler anemometry, we provide angular velocity profiles and in particular identify the radial position of the neutral line, defined by for fixed height . For these large values, the ratio , which is close to , is distinguished by a zero angular velocity gradient in the bulk. While for moderate counter-rotation , the neutral line still remains close to the outer cylinder and the probability distribution function of the bulk angular velocity is observed to be monomodal. For stronger counter-rotation the neutral line is pushed inwards towards the inner cylinder; in this regime the probability distribution function of the bulk angular velocity becomes bimodal, reflecting intermittent bursts of turbulent structures beyond the neutral line into the outer flow domain, which otherwise is stabilized by the counter-rotating outer cylinder. Finally, a hypothesis is offered allowing a unifying view and consistent interpretation for all these various results.

Inertial confinement fusion using light ion beams requires fast rise time, high power drivers. One technique to enhance a conventional pulsed power generator is to use a plasma erosion opening switch (PEOS) between the generator and the ion diode. Ideally, the PEOS conducts current until a current threshold is reached, then rapidly opens and delivers the inductively stored energy to the load on a short time scale. Experiments at the Naval Research Laboratory (NRL) used a PEOS to improve the Gamble II current rise time from 60 ns to 10 ns at 1 MA. Load voltages over 4 MV have been obtained (>2× the matched load voltage).

Based on these experiments and theoretical predictions, a PEOS system has been incorporated into the PBFA II experiment at Sandia National Laboratories (SNL). The PEOS on PBFA II is ultimately to provide a 6 to 8-MA, 30-MV pulse with 10-ns rise time into an “applied B” ion diode. This is a large extrapolation of present experiments. The PEOS system on PBFA II is described here and theoretical predictions are given.

Summary

Objective: The objective of this study was to describe the diastolic pressure–flow relationship and to assess critical occlusion pressure in arterial coronary bypass grafts in human beings. Methods and results: Fifteen patients were studied following elective surgical coronary artery bypass grafting. Flow in the left internal mammary artery bypass to the left anterior descending artery was measured and simultaneously, aortic pressure, coronary sinus pressure and left ventricular end-diastolic pressure were recorded. The zero-flow pressure intercept as a measure of critical occlusion pressure was extrapolated from the linear regression analysis of the instantaneous diastolic pressure–flow relationship. Mean diastolic flow was 46 ± 17 mL min−1, mean diastolic aortic pressure was 60.5 ± 10.0 mmHg. Diastolic blood flow was linearly related to the respective aortic pressure in all patients (R-values 0.7–0.99). The regression lines had a mean slope of 2.1 ± 1.2 mL min−1 mmHg−1. Mean critical occlusion pressure was 32.3 ± 9.9 mmHg and exceeded mean coronary sinus pressure and mean left ventricular end-diastolic pressure by factors of 3.1 and 2.6, respectively. Conclusions: Our data demonstrate the presence of a vascular waterfall phenomenon in the coronary circulation after internal mammary artery bypass grafting. Critical occlusion pressure in arterial grafts considerably exceeds coronary sinus pressure as well as left ventricular end-diastolic pressure and should thus be used as the effective downstream pressure when calculating coronary perfusion pressure. Our data further suggest that the slope of diastolic pressure–flow relationships provides a more rational approach to assess regional coronary vascular resistance than conventional calculations of coronary vascular resistance.

In this paper the temperature dependence of reversible and irreversible polarization contributions in the temperature range between 223 K and 473 K is investigated to elucidate the microscopic mechanism responsible for reversible and irreversible changes of the ferroelectric polarization. Small signal capacitance measurements under dc-bias are used to measure the reversible contributions. Quasi-static hysteresis measurements are used to obtain the total polarization, i.e. the sum of the reversible and irreversible contributions. The combination of both measurements allows the separation of the reversible and irreversible parts. The reversible and irreversible contributions are demonstrated for SrBi2Ta2O9 (SBT), SrBi2Ta2-xNbxO9 (SBTN) thin films and compared to tetragonal PbZr0.3Ti0.7O3 (PZT) thin film capacitors.

The imprint behavior of CSD processed SrBi2Ta2O9 (SBT) thin films has been investigated as a function of time, applied bias, illumination with band gap light and post anneal under different oxygen partial pressures. Applying a bias in the direction of the polarization enhances the tendency of the capacitor to exhibit a voltage shift as well as illuminating the poled capacitor with band gap light. Post anneal after top electrode deposition and patterning under slightly reducing atmospheres does not affect the imprint rate. From these experimental results, a model is presented which explains the imprint behavior of SBT films by transport of electronic charges from the electrodes into the film and subsequent trapping of these charges near the interface.

The final Tycho Catalogue (ESA 1997b) has been derived from 37 months of observations with the star mapper of the astrometric satellite Hipparcos. The Hipparcos Catalogue (ESA 1997a) with about 120,000 stars is the result of the main Hipparcos mission and has, e.g., been described by Kovalevsky et al. (1995). Both catalogues will be published in 1997.

This work presents a survey of the mechanisms of the polarization in ferroelectric thin films which are relevant for application in non-volatile ferroelectric memories (FeRAM). Since the integration of these materials in new memory generations requires small structures and therefore a maximum utilization of the switchable polarization, the distinction between the several polarization mechanisms is of specific interest. Standard characterization methods, such as hysteresis loops, C-V measurements and fast pulse switching tests are evaluated and used to distinguish between the reversible and irreversible contributions to the total polarization. The respective contributions are described qualitatively and demonstrated at spin-coated SrBiTa2O9 thin films and compared with Pb(Zr,Ti)O3 films. Additionally, a method is described to obtain the static hysteresis curve, a precise characterization of the polarization which does not depend on the measuring frequency. These data are compared with C-V measurements. It is shown that the standard dynamic hysteresis curve reveals misleading statements about the remanent polarization and the coercive voltage.

A donor-like spectrum in Fe-doped silicon has been studied by means of high-resolution Zeeman spectroscopy. Previous work had unambigouosly identified the center as the interstitial iron impurity and the spectrum was interpreted as due to the transitions , where an electron is excited to shallow effective-masslike donor states. In this paper, we can, by studying the transitions in a magnetic field, verify the effective-mass-like character of the loosely bound electron. Furthermore, we also obtain information on the impurity core whose level structure is reflected in the observed superposition of donor-hke Rydeberg series and whose g values determines the Zeeman splitting pattern.

Recent absorption and photoconductivity studies of deep transition-metal impurities in silicon are discussed, with emphasis on optical transitions from the deep ground state to shallow Coulomb excited states. The P3/2 line spectra of the deep Au and Pt acceptors closely resemble those of group II acceptors in silicon, whereas the P1/2 lines show resonance effects due to interaction with the valence band continuum. Behavior under uniaxial stress is compatible with D2d or C 2y point-group symmetry for the Au and Pt acceptors. A line spectrum in g-dopes Si can be attributed to excitations to shallow donor states since the phononassisted Fano resonances involve characteristic inter-valley phonons. Both the Ag donor spectrum and the corresponding Au spectrum are dominated by excited s-state transitions. Thus, the traditional fingerprint of a donor in silicon, i.e. the effective-mass like p-state series, is missing or at best observed weakly