Eine allgemeine Berechnungsmethode für Wärmeübertragerschaltungen

A general method for calculating any heat exchanger network is presented. As heat exchanger networks can be considered as coupled heat exchangers, that are supplied in a predetermined order, it is convenient to consider even a single heat exchanger with complicated flow patterns as a network composed of several ideally-supplied, coupled devices. The advantage of this method lies in its higher accuracy and the use of a simpler calculation formula for an ideal device model. These advantages far outweigh the disadvantages of the arduous iterative type of calculation used to establish the temperature between ideal devices. The presented method allows, for the first time, without using the iterative method, a calculation of heat exchanger networks based upon the principle of coupled matrix equations. These equations are for any given heat exchanger network simply allocated parameters, and therefore this method is especially suited for the calculation of any network modification. For the application of this method is no special software necessary. The solution of the model equations is obtained very easy and clear with mathematical standard software, e.g. Mathcad or Maple.     

Biologically active secondary metabolites of barley. IV. Hordenine production by different barley lines

Forty-three lines of barley, including ancestral (wild), landraces, Middle Eastern lines, and modern cultivars, were grown under two different sets of environmental conditions. Hordenine production in barley roots was determined at the one-leaf stage by HPLC analysis and, in two lines only, over a period of 35 days. Forty-two of the 43 lines produced significant amounts of hordenine, although there was no variation among groups. Middle Eastern lines had the highest production with 327 µg/g on a dry weight basis. Production was, however, determined more by environmental conditions during growth than by genetic factors. Hordenine production was up to seven times higher in plants grown under lower light intensities.     

Societal Safety: Concept,Borders and Dilemmas

In most industrialized countries, the end of the Cold War marked a change in focus from preparedness for war to an increasing focus on civil society's own vulnerability and safety. To meet new threats and changing risks, there is also a need for new analytical concepts. Societal safety is a concept developed in Norway during the last decade. It could be defined as: ‘The society's ability to maintain critical social functions, to protect the life and health of the citizens and to meet the citizens' basic requirements in a variety of stress situations’. It aims to be a systematic approach for understanding, mitigating and responding to social problems such as extraordinary stresses and losses, interferences in complex and mutual dependent systems, or lack of trust in vital social institutions. Future threats to society are not limited to specific sectors or areas, but stem from complex interactions amongst economic, technological, social and cultural factors. Thus, the main challenges to improve societal safety will be the ability to coordinate, organize and assign clear roles to different actors at the international, national and local levels. Societal safety has interfaces with other safety‐related areas such as national security, sustainable development, human security and incident management (handling of isolated accidents, common illness and ordinary criminal acts). Societal safety is, however, a sensitive political issue containing dilemmas and value choices that are hardly possible to perceive or solve as pure scientific problems.     

Prognosis of hematological patients with relapse following high-dose chemotherapy and autologous stem cell transplantation

A retrospective analysis of the outcome for 283 haematological patients who relapsed after high dose chemotherapy and autologous stem cell transplantation during a five year period from 1989 to 1994 is presented. The patients were treated in accordance with local regimes at 20 Nordic transplantation centers and included patients with acute leukemia (157 patients), multiple myeloma (16 patients) and lymphoma (110 patients). Two hundred and twenty-nine patients with relapse or progressive disease were given chemo- and/or radiotherapy and the response was evaluated after 90 days. Fifty-four patients (24%) obtained a complete remission and 44 patients (19%) partial remission. The overall median survival after relapse was five months. In the group who received salvage treatment the median survival was seven months, and for the 54 patients in complete remission the median survival was 15 months. We found that survival after relapse depends upon primary disease, the time from transplantation to relapse and whether salvage therapy was initiated.     

An Operator-integration-factor splitting method for time-dependent problems: Application to incompressible fluid flow

In this paper we present a simple, general methodology for the generation of high-order operator decomposition (splitting) techniques for the solution of time-dependent problems arising in ordinary and partial differential equations. The new approach exploits operator integration factors to reduce multiple-operator equations to an associated series of single-operator initial-value subproblems. Two illustrations of the procedure are presented: the first, a second-order method in time applied to velocity-pressure decoupling in the incompressible Stokes problem; the second, a third-order method in time applied to convection-Stokes decoupling in the incompressible Navier-Stokes equations. Critical open questions are briefly described.