Effectiveness evaluation of STOL transport operations (phase 2)

A computer simulation program which models a commercial short-haul aircraft operating in the civil air system was developed. The purpose of the program is to evaluate the effect of a given aircraft avionics capability on the ability of the aircraft to perform on-time carrier operations. The program outputs consist primarily of those quantities which can be used to determine direct operating costs. These include: (1) schedule reliability or delays, (2) repairs/replacements, (3) fuel consumption, and (4) cancellations. More comprehensive models of the terminal area environment were added and a simulation of an existing airline operation was conducted to obtain a form of model verification. The capability of the program to provide comparative results (sensitivity analysis) was then demonstrated by modifying the aircraft avionics capability for additional computer simulations

Winding problems with rotogravure jumbo-rolls

The production and conversion of jumbo rolls presents a challenge to all involved in the production process. This presentation shows that as reel dimensions continue to increase, limits are being reached with regard to engineering and production. This applies to the paper, the core and particularly to winders and printing machine unwinds. The two problems areas, on the one hand crepe wrinkles and bursts in the reel centre when rewinding and unwinding and on the other hand the danger of the core disintegrating in the winder machine unwind, which can have serious consequences, can only be solved jointly by those involved in the whole process. One effective measure will be to use 150 mm cores instead of the 76 mm core for extremely heavy jumbo reels. This will represent an initial decisive breakthrough to improve the situation. Further optimisation in paper making and converting, in core geometry, strength and stiffness as well as in the design of winders and printing machine unwinds will ensure that the manufacture and conversion of jumbo reels meet the requirements posed

Future online concept for roll and sheet production in papermaking technology and process requirements for web handling

The process of on-line converting is discussed as a chance to increase the productivity and quality in roll and sheet converting in paper mills. In this article the technical and process related prospects will be presented on the basis of an exemplary production line (WFC Paper) and transferred into realizable concepts for continuity paper converting.In the case of roll production, the segment of large rolls with standard sizes is very suitable for an on-line-production, and in the case of sheet production the segment of larger lot sizes. In both cases a new machine design with altered functions and a higher level of automation and process control is necessary.These alterations yield diverse requirements for web and sheet handling, which have to be fulfilled for a continuous and high-quality production. All fundamental technologies such as transport mechanics of webs and sheets, winding and stacking mechanics, slitting in length and cross direction as well as measurement and control techniques for the monitoring of converting processes in particular belong to this category. These technologies will be discussed and further tasks for research work will be presented

Nanocalorimetric Evidence for Nematic Superconductivity in the Doped Topological Insulator Sr0.1_{0.1}Bi2_{2}Se3_{3}

Spontaneous rotational-symmetry breaking in the superconducting state of doped $\mathrm{Bi}_2\mathrm{Se}_3$ has attracted significant attention as an indicator for topological superconductivity. In this paper, high-resolution calorimetry of the single-crystal $\mathrm{Sr}_{0.1}\mathrm{Bi}_2\mathrm{Se}_3$ provides unequivocal evidence of a two-fold rotational symmetry in the superconducting gap by a \emph{bulk thermodynamic} probe, a fingerprint of nematic superconductivity. The extremely small specific heat anomaly resolved with our high-sensitivity technique is consistent with the material's low carrier concentration proving bulk superconductivity. The large basal-plane anisotropy of $H_{c2}$ is attributed to a nematic phase of a two-component topological gap structure $\vec{\eta} = (\eta_{1}, \eta_{2})$ and caused by a symmetry-breaking energy term $\delta (|\eta_{1}|^{2} - |\eta_{2}|^{2}) T_{c}$. A quantitative analysis of our data excludes more conventional sources of this two-fold anisotropy and provides the first estimate for the symmetry-breaking strength $\delta \approx 0.1$, a value that points to an onset transition of the second order parameter component below 2K

Scaling of the Equilibrium Magnetization in the Mixed State of Type-II Superconductors

We discuss the analysis of mixed-state magnetization data of type-II superconductors using a recently developed scaling procedure. It is based on the fact that, if the Ginzburg-Landau parameter kappa does not depend on temperature, the magnetic susceptibility is a universal function of H/H_c2(T), leading to a simple relation between magnetizations at different temperatures. Although this scaling procedure does not provide absolute values of the upper critical fieldH_c2(T), its temperature variation can be established rather accurately. This provides an opportunity to validate theoretical models that are usually employed for the evaluation of H_c2(T) from equilibrium magnetization data. In the second part of the paper we apply this scaling procedure for a discussion of the notorious first order phase transition in the mixed state of high temperature superconductors. Our analysis, based on experimental magnetization data available in the literature, shows that the shift of the magnetization accross the transition may adopt either sign, depending on the particular chosen sample. We argue that this observation is inconsistent with the interpretation that this transition always represents the melting transition of the vortex lattice.Comment: 18 pages, 12 figure

Quantitative analysis of nip-induced tension by use of digital image processing

Winding paper in contact with a drum leads to the production of nip-induced tension which, to a high degree, influences the structure of the roll. Thus, comprehending the processes in the nip, including each parameter involved, is desirable to avoid roll defects.This paper deals with a new measurement technique that is able to observe the process of building up nip-induced tension in the outer layers of a roll. With the use of digital image processing, this method ensures the registration of the two-dimensional displacement field of the outer layers with fairly high precision. Based on the first principal of the equations of mechanics, it is possible to derive the stress and strain in the layers from the displacement field. Thus, it succeeds to calculate the tangential stress in the outer layers of a roll taking the compression as well as the slippage of the layers into account.In all experimental test series the tangential stress increases within the first 4 to 15 layers to a maximum value. Afterwards, there is still a considerable displacement of the layers relative to the core, but the layer-to-layer slippage is so small that the change in strain is negligible. Furthermore, it is shown that there is a reduced increase of nip-induced tension in the first approximate 50 layers near the core. Comparing the nip-induced displacement of different type of papers, there are clearly differences noticeable concerning the amount of displacement, as well as the rapidness of increase to the final displacement