On the application of vibratory disk feeders for silos

Originally vibratory disk-feeders and-reclaimers were designed with rather small diameters. They were mainly applied in chemical process plants, and were mostly flush mounted underneath bins of modest size, say up to 1 m diameter. Over the past decades they have been increasingly used for bins of much larger diameter, some via a hopper and some not. The latter may cause an unfortunate combination of the most important parameters, leading to malfunctioning and even to feeder jam. This work shows that basically vibratory disk feeders should be installed via a hopper, which for practical reasons becomes feasible above diameters of approximately 0.8 m, depending on the material to be reclaimed and the required mass flow. Feeders of considerable size, up to 2.5 m, may very well operate satisfactorily when properly mounted underneath a hopper. Nonfunctioning of vibratory disk feeders is mostly caused by a combination of too bad flowability of the bulk material to be reclaimed; too high a feeder load and wrong silo fill procedures and feeder power-up procedures.     

A quick point-in-polyhedron test

To decide whether a point is contained in a polyhedron, one may use the parity of the number of intersections of a halfline with the boundary of the polyhedron. Difficulties arise if the halfline meets an edge or a vertex. To resolve such singularities, we propose to associate to each point of intersection a certain positive or negative weight and then to consider the sum of these weights.     

Antineoplastic activity of the thioether lysophospholipid derivative BM 41.440 in vitro

Thioether lysophospholipid derivatives (TLP) inhibited the in vitro uptake of [³H]thymidine into blasts of eight leukemias and cells of 12 different solid tumors of human origin. This effect correlated with trypan blue dye exclusion, which was used to assess cell damage. Cytostatic and cytotoxic effects of TLP were dependent on dosage and incubation time. Destruction of leukemic blasts was completed with >5 μg/ml after an incubation of >48 hr, but 10 to 20 μg/ml were necessary in solid tumors. Ester-linked 2-lysophosphatidylcholine was ineffective in the same dose range, which points to the requirement of the alkyl moiety insn-1 and a stablesn-2 substitution of the molecule for the antineoplastic effect. To assess putative antileukemic selectivity, the cytotoxicity (trypan blue dye exclusion) of TLP was compared in human cell samples of 19 non-neoplastic bone marrows and 9 leukemias. Results revealed a significantly higher activity of the TLP BM 41.440 in leukemic blasts.     

Towards a dynamic balance between humans and automation: authority, ability, responsibility and control in shared and cooperative control situations

Progress enables the creation of more automated and intelligent machines with increasing abilities that open up new roles between humans and machines. Only with a proper design for the resulting cooperative human–machine systems, these advances will make our lives easier, safer and enjoyable rather than harder and miserable. Starting from examples of natural cooperative systems, the paper investigates four cornerstone concepts for the design of such systems: ability, authority, control and responsibility, as well as their relationship to each other and to concepts like levels of automation and autonomy. Consistency in the relations between these concepts is identified as an important quality for the system design. A simple graphical tool is introduced that can help to visualize the cornerstone concepts and their relations in a single diagram. Examples from the automotive domain, where a cooperative guidance and control of highly automated vehicles is under investigation, demonstrate the application of the concepts and the tool. Transitions in authority and control, e.g. initiated by changes in the ability of human or machine, are identified as key challenges. A sufficient consistency of the mental models of human and machines, not only in the system use but also in the design and evaluation, can be a key enabler for a successful dynamic balance between humans and machines.     

Data-Flow Frameworks for Worst-Case Execution Time Analysis

The purpose of this paper is to introduce frameworks based on data-flow equations which estimate the worst-case execution time (WCET) of real-time programs. These frameworks allow several different WCET analysis techniques with various precisions, which range from naïve approaches to exact analysis, provided exact knowledge on the program behavior is available. In addition, data-flow frameworks can also be used for symbolic analysis based on information derived automatically from the source code of the program.     

Das Makrozoobenthos als Indikatorgruppe zur Bewertung großer Flüsse unter Einbeziehung auenökologischer Aspekte

With the guideline 2000/60/EG, which called for the creation of a framework on water policy, the environmental policy of the European Community took on a new dimension. The goal of the guideline is (among others) the creation of a framework for the protection of inland surface waters, transitional waters, coastal waters and groundwater in order to avoid their deterioration; and to protect and improve the status of aquatic ecosystems, their associated land ecosystems directly dependent on them, and wetlands in terms of their water budget. Thanks to various forms of use, e.g. hydropower production, flood protection and ship traffic, especially major European rivers like the Danube, Rhine and Elbe have changed massively from their original typological characteristics. Reference conditions are hardly anywhere to be found, many native species are now extinct, and river biotopes are often dominated by invasive species. The size and depth of these rivers also pose challenges in terms of taking samples, and it has also become apparent that all methods currently used to assess rivers’ ecological status focus solely on the main channels; the various habitats to be found in large rivers’ riparian systems aren’t taken into account. However, there is international consensus that these systems are key elements in rivers’ processes and biodiversity, and as such are significant for the continuing functionality of major rivers. In the context of an Austrian Ministry of Life-funded research project, the Institute of Hydrobiology and Aquatic Ecosystem Management’s Working Group on Benthic Ecology and Ecological Status Assessment, together with the University of Vienna and the Environment Agency Austria, is currently working to develop a practice-oriented riparian zone index based on macrozoobenthos as an indicator of quality. To date, Europe has no Water Framework Directive-compliant assessment systems for riparian zones. Given the fact that established methods are limited to river’s main channels, precluding a holistic view of and approach to river ecosystems, this project represents a pioneering work in the field of European water resource management.