Formation of A15-phase in Ta/ Nb3Al0.75Ge0.25-powder - and Nb/ Nb3Al0.75Ge0.25-powder - composites and their superconducting properties

The experiments were done using a powder mixture of Nb, Al and Ge with a particle diameter of less than 50 μm which was filled into Ta- or Nb-tubes. These composites were cold-worked and heated from 400°C (10°C/min) up to 850 or 900°C and annealed 20 min on this temperature. By this heat treatment in many areas the intermetallic compound Nb(Al,Ge)3is formed within the powder mixture. After a second cold deformation the composites were annealed at 1000, 1200 or 1300°C with different annealing times. Microprobe analysis was used to investigate the phase distribution. The formation of the A15-phase was also investigated by transition temperature measurements, which were done by the inductive method. The highest transition temperature was found after 1300°C furnace annealing. Maximum critical current was achieved by short-time resistive annealing at 1200°C of 0.5 mm θ wire. The reason for the high current carrying capacity of the short-time annealed samples can be seen from the Tc-measurements which show that a A15-phase with high transition temperature is formed even after a short annealing time. Possible improvements of superconductors made from powder mixtures are discussed.     

Resampling, Antialiasing, and Compression in Multiview 3-D Displays

Multiview three-dimensional (3-D) displays offer viewing of high-resolution stereoscopic images from arbitrary positions without glasses. This article surveyed different approaches to develop signal processing algorithms for these displays. Such displays consist of view-dependent pixels that reveal a different color according to the viewing angle. Therefore, the left and right eye of an observer sees slightly different images on the screen. This leads to the perception of 3-D depth and parallax effects when the observer moves. Although the basic optical principles of multiview auto-stereoscopy have been known for over a century, only recently displays with increased resolution, or systems based on multiple projectors, have made this approach practical.     

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Accelerated radiotherapy regimen for malignant gliomas using stereotactic concomitant boosts for dose escalation

Parvovirus B19 (PV B19) infection was investigated in 29 pregnant women with fetal hydrops, after exclusion of feto-maternal incompatibility within red blood cell antigens, TORCH infections, feto-maternal hemorrhage and genetics reasons. The active viral infection was detected in 9 women (31%) by PCR amplification of DNA B19; in 2 of them IgM and IgG, in 1 IgM and in 4 IgG antibodies were also present. In 6 women (20%) IgG antibodies were only found, but not IgM and DNA B19, which confirmed infection in the past. In addition in 9 cases DNA B19 was evaluated in the fetal blood. The results in the mothers and their fetuses were concordant (4 positive, 5 negative). Our conclusion is that in nonimmune hydrops fetalis, PV B19 infection should be based on the viral DNA evaluation in the blood of mother (or fetus). IgM antibodies, in time of fetal disorders, might not be detected.     

System Dynamics in inventory and production planning

Summary The fundamentals of the modelling approach System Dynamics are described and illustrated by two simple inventory and production planning models. After discussing the structure of an implemented System Dynamics model the applicability of this modelling approach is critically analysed.

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Zusammenfassung Die Elemente der Modellierungskonzeption System Dynamics werden beschrieben und anhand von zwei einfachen Lager- und Produktionsplanungsmodellen demonstriert. Nach der Darstellung des Aufbaus eines implementierten System Dynamics Modells wird die Anwendbarkeit dieses Modellierungskonzeptes kritisch analysiert.

     

Temporally Consistent Motion Segmentation From RGB‐D Video

Temporally consistent motion segmentation from RGB‐D videos is challenging because of the limitations of current RGB‐D sensors. We formulate segmentation as a motion assignment problem, where a motion is a sequence of rigid transformations through all frames of the input. We capture the quality of each potential assignment by defining an appropriate energy function that accounts for occlusions and a sensor‐specific noise model. To make energy minimization tractable, we work with a discrete set instead of the continuous, high dimensional space of motions, where the discrete motion set provides an upper bound for the original energy. We repeatedly minimize our energy, and in each step extend and refine the motion set to further lower the bound. A quantitative comparison to the current state of the art demonstrates the benefits of our approach in difficult scenarios.     

EWA splatting

We present a framework for high quality splatting based on elliptical Gaussian kernels. To avoid aliasing artifacts, we introduce the concept of a resampling filter, combining a reconstruction kernel with a low-pass filter. Because of the similarity to Heckbert's (1989) EWA (elliptical weighted average) filter for texture mapping, we call our technique EWA splatting. Our framework allows us to derive EWA splat primitives for volume data and for point-sampled surface data. It provides high image quality without aliasing artifacts or excessive blurring for volume data and, additionally, features anisotropic texture filtering for point-sampled surfaces. It also handles nonspherical volume kernels efficiently; hence, it is suitable for regular, rectilinear, and irregular volume datasets. Moreover, our framework introduces a novel approach to compute the footprint function, facilitating efficient perspective projection of arbitrary elliptical kernels at very little additional cost. Finally, we show that EWA volume reconstruction kernels can be reduced to surface reconstruction kernels. This makes our splat primitive universal in rendering surface and volume data.