Rectangular mode transformers in tapered single-mode fibres

A single-mode fibre, polished on both sides and subsequently tapered, yields a low-loss circular-to-rectangular mode transformer. This device should permit more efficient interconnection of circular fibres to rectangular integrated-optic and semiconductor waveguides.<>     

Wirtschaftlichkeit als Kriterium für die Entwicklung,Auslegung und Auswahl von Apparaten und Maschinen für Prozeßstufen

Economy as a criterion for development, design, and choice of equipment and machines for process steps . The object of this paper is to show how a supplier of individual machines can influence the total costs of a chemical processing plant. This influence is quantified using actual examples based on the development of a product range, the optimizing and matching together of mechanical and thermal separation processes, and the selection of the most suitable types of equipment. Studies show that the products and services of an equipment manufacturer can influence substantially more than just capital investment costs and interest charges with their consequent effects on the annual running costs of a plant. It is possible to reach more economical solutions for important stages in a manufacturing process if the plant designers and the equipment manufacturers work closely together. A too tightly specified enquiry can prevent a manufacturer from offering the technically and economically optimized solution. By involving equipment manufacturers and correctly using their know-how one can tap a substantial potential for the reduction of plant running costs.     

A Visual Model Weighted Cosine Transform for Image Compression and Quality Assessment

Utilizing a cosine transform in image compression has several recognized performance benefits, resulting in the ability to attain large compression ratios with small quality loss. Also, incorporation of a model of the human visual system into an image compression or quality assessment technique intuitively should (and has often proven to) improve performance. Clearly, then, it should prove highly beneficial to combine the image cosine transform with a visual model. In the past, combining these two has been hindered by a fundamental problem resulting from the scene alteration that is necessary for proper cosine transform utilization. A new analytical solution to this problem, taking the form of a straightforward multiplicative weighting function, is developed in this paper. This solution is readily applicable to image compression and quality assessment in conjunction with a visual model and the image cosine transform. In the development, relevant aspects of a human visual system model are discussed, and a refined version of the mean square error quality assessment measure is given which should increase this measure's utility.     

Neutron radiation area monitoring system for proton therapy facilities

A neutron radiation area monitoring system has been developed for proton accelerator facilities dedicated to cancer therapy. The system comprises commercial measurement equipment, computer hardware and a suite of software applications that were developed specifically for use in a medical accelerator environment. The system is designed to record and display the neutron dose-equivalent readings from 16 to 24 locations (depending on the size of the proton therapy centre) throughout the facility. Additional software applications provide for convenient data analysis, plotting, radiation protection reporting, and system maintenance and administration tasks. The system performs with a mean time between failures of >6 months. Required data storage capabilities and application execution times are met with inexpensive off-the-shelf computer hardware.     

S-oxygenation of thiourea results in the formation of genotoxic products

Thiourea (TU) is a thyroid carcinogen which has previously been shown to cause genotoxicity in various test systems in vitro and in vivo. The mechanism underlying these effects has not yet been elucidated. The present study addressed the question of whether the formation of oxidized products of TU might be involved in genotoxicity. Chemical oxidation of [14C]TU with hydrogen peroxide in the presence of calf thymus DNA resulted in the formation of [14C]formamidine sulfinate ([14C]FASA), [14C]cyanomide, and [14C]urea and in covalent binding of radioactivity to the DNA. Incubation of V79 Chinese hamster cells with 10-20 mM TU for 18 hr but not for 3 hr, increased the frequency of micronuclei to a slight extent. In cells depleted of glutathione, which can prevent the oxidation of TU, micronucleus induction by TU was more pronounced and detectable both after 3 and 18 hr of incubation. Exposure of the cells to 1.25 to 10 mM FASA for 3-5 hr induced micronuclei, DNA repair synthesis, and gene mutations in the cells. Flavin-containing monooxygenase (FMO], an enzyme known to catalyze the S-oxygenation of TU in liver, could not be detected in the postmitochondrial supernatant (S-9) of the V79 cells. There is evidence, however, that TU can easily autoxidize to S-oxygenated products. Both FASA and TU caused a slight induction of DNA repair synthesis in cultured rat hepatocytes, but FASA was active at lower concentrations than TU. Cyanamide did not elicit repair. The finding that FASA, a product of both the nonenzymatic and the enzymatic S-oxygenation of TU, is genotoxic in cultured mammalian cells provides for the first time a hypothesis to explain the genotoxicity of TU.     

Converter Propulsion Systems with Three-Phase Induction Motors for Electric Traction Vehicles

Three-phase induction machines have a number of advantages compared with collector type machines which make them particularly suitable for traction purposes. These advantages, which were recognized long before, could only be used in praxis by means of the progress, which the development of static power converters has made in the last decade. Primarily having been used in diesel-electric traction vehicles inverter-fed three-phase induction motors are now going to be applied in large scale to line-fed electric vehicles. In this field of application the induction machine has some additional advantages; e.g., the motor torque versus speed curve declines much less with increasing speed than that of the common series wound ac machine. Consequently, for the first time in history universal electric locomotives can be built, which are equally suited for hauling high-speed passenger trains as well as heavy freight trains. Converter systems are described, which do not drain reactive power from the supply line or even feed reactive power into the line, if necessary, and produce only a small amount of harmonics. Hence these systems are very well suited for high-power electric traction vehicles as well as for smaller vehicles, which are in service simultaneously in one district (e.g., rapid transit vehicles), and for industrial locomotives. Finally, some test and production vehicles with three-phase induction motors, test data, and experiences in service of such vehicles are described.     

Die Bedeutung der Lieferkette für den Klimafußabdruck von Unternehmen

In climate footprints of countries, but also of companies, the use of goods that come from outside makes a considerable contribution. For companies, capturing these greenhouse gas emissions is difficult because they occur in the supply chain, which can usually only be traced to the first supplier. Input-output analysis methods can be used to estimate emissions in supply chains. They provide indications of the origin of emissions by country and industry sector or product group. With recursive methods in the supply chain, these calculations can be continuously improved.     

VISTA: visual interpretation system for technical applications-architecture and use

The present state of the construction of a vision system for the fast interpretation of complicated industrial scenes is reported. The system is being built at the Fraunhofer Institute for Information and Data Process in Karlsruhe, West Germany. The scenes for which the system is intended are also presented. They form the basis for specifying the requirements for the system called VISTA. Its principal architecture as a bus-oriented multiprocessor system is discussed. Some special hardware modules of VISTA are described in more detail, and its basic software concept is introduced. As an application, detection and classification of defects that appear in automatic visual inspection of hard wood are reviewed. Using special modules for the iconic and the symbolic stage, VISTA is capable of real-time processing and evaluation of endless images, image sequences, images of various formats, and multisensorial data     

Stereoselective reversible ketone formation from 10-hydroxylated nortriptyline metabolites in human liver

1. E- and Z-10-hydroxynortriptyline are major metabolites of amitriptyline and nortriptyline in man. Upon incubation with human liver microsomes or cytosol, these metabolites were oxidized to the corresponding ketones, E- and Z-10-oxonortriptyline. (+)-E- and (+)-Z-10-hydroxynortriptyline were distinctly preferred over the (-)-isomers as substrates. NADP+ supported the oxidation in cytosol, whereas in microsomes NAD+ was the best cofactor. 2. Incubation of E- and Z-10-oxonortriptyline with NADPH and cytosol resulted in the nearly exclusive formation of (+)-E- and (+)-Z-10-hydroxynortriptyline. Kinetic analysis revealed high-affinity reduction (K(m) 1-2 microM) of the two ketones and an additional low-affinity component with the E-isomer. 10-Oxonortriptyline reduction was also catalysed by rabbit, but not by rat or guinea pig liver cytosol. 3. With [4-3H]NADPH as cosubstrate, tritium was incorporated into E- and Z-10-hydroxynortriptyline preferentially from the pro-4R position. Redox cycling of (+)-E- and (+)-Z-10-hydroxynortriptyline in cytosol in the presence of NAD- and NADPH was indicated by 3H incorporation from [pro-4R-3H]NADPH. 4. Recombinant human carbonyl reductase catalysed low-affinity reduction of E-10-oxonortriptyline with preferential transfer of the pro-4S-3H of labelled NADPH. 5. Ketone reduction in cytosol was strongly inhibited by 9,10-phenanthrenequinone and dehydrolithocholic acid and moderately by other 3-oxo steroids and some anti-inflammatory drugs. 6. The high-affinity reduction of E- and Z-10-oxonortriptyline and the oxidation of the alcohols in cytosol are probably mediated by a member of the aldo-keto reductase family of enzymes.     

List and soft symbol output Viterbi algorithms: extensions andcomparisons

The Viterbi algorithm (VA) is the maximum likelihood decoding algorithm for convolutionally encoded data. Improvements in the performance of a concatenated coding system that uses VA decoding (inner decoder) can be obtained when, in addition to the standard VA output, an indicator of the reliability of the VA decision is delivered to the outer stage of processing. Two different approaches of extending the VA are considered. In the first approach, the VA is extended with a soft output (SOVA) unit that calculates reliability values for each of the decoded output information symbols. In the second approach, coding gains are obtained by delivering a list of the L best estimates of the transmitted data sequence, namely the list Viterbi decoding algorithm (LVA). Our main interest is to evaluate the LVA and the SOVA in comparison with each other, determine suitable applications for both algorithms and to construct extended versions of the LVA and the SOVA with low complexity that perform the task of the other algorithm. We define a list output VA using the output symbol reliability information of the SOVA to generate a list of size L and that also has a lower complexity than the regular LVA for a long list size. We evaluate the list-SOVA in comparison to the LVA. Further, we introduce a low complexity soft symbol output viterbi algorithm that accepts the (short) list output of the LVA and calculates for each of the decoded information bits a reliability value. The complexity and the performance of the soft-LVA (LVA and soft decoding unit) is a function of the list size L. The performance of the soft-LVA and the SOVA are compared in a concatenated coding system. A new software implementation of the iterative serial version of the LVA is also included