Comment and discussion on digital processing of PD pulses

Some of the more salient aspects of the digital processing technology of PD signals are examined. Most of the efforts in this field are concentrated on the application of digital analyzers for pulse height analysis, pattern recognition and identification of the physical phenomena. It is demonstrated that errors in the signal processing unit can lead to dominant mistakes in the interpretation of the test results     

Ozonation of Two Acidic Azo Dyes with Different Substituents

The ozonation of two differently substituted azo dyes (Schwarz GRS and Orange Acid 8) in water media is studied. The influence of pH on the effectiveness of the ozonation at various initial concentrations of each dye is explored. It was found out that the rates of decolorization for amino-group substituted dyes reflect the considerable influence by the widely varying initial pH from 4.5 to 10. Specifically, the highest effect of decolorization of this dye was obtained at the highest pH studied (pH 10) for all initial concentrations of the solutions. Considering the dye without an amino-group substitute, the rates of color disappearance in ozonation reflected to a lower degree the variations of the initial pH. Pseudo-first-order trends of decolorization were observed in all the experimental runs. Regarding the kinetic results obtained, an attempt to explain the different dyes reactivity was made based on the absolute electronegativity (E_lumo + E_homo) of both dyes. The COD/BOD analysis shows that the ozonation of both azo dyes can reduce the sample COD but it could not improve the biodegradability ratio (BOD₅/COD). BOD decrease with ozonation time indicates that the intermediates of the ozonation are of lower biodegradability. Oxalic acid was found as the final product of ozonation of both dyes.     

Introduction

Concluding remarks With this brief exposition of the areas covered in this special double issue on Eurotra, we shall now conclude our introduction. We hope that the volume will achieve its goals, as outlined above, at least to some extent. Certainly, much more could be said about a wide range of topics which have been covered in the lifetime or the project so far. For instance, these article, mainly written by linguists, deliberately neglect the software implementation and environment aspects of the prototype Eurotra Translation System, as well as a number of peripheral tools and components of the system that are available to the user, such as lexical data bases, text-handling mechanisms and the like. The reader interested in aspects of this kind is referred to Raw et al. 1989 for a very brief introduction, and to the Eurotra software team at the Commission of the European Communities (DG XIII, Luxembourg) for more details. However, one goal that we do hope to come close to achieving is to give a fair overview of the Eurotra linguistic theory of translation and the mainstream and sideline formalisms expressing variant versions of it. If we have come anywhere near achieving that, our gratitude is due to the numerous Eurotra colleagues who have supported us in preparing this volume, and to the editor of this journal.     

Xylose-lysine model systems: The effect of pH on the volatile reaction products

Aqueous molal solutions of xylose and lysine (initial pH 4–9) were refluxed either with control of the pH at 5–0 or without pH control (final pH 2–6). Analysis by gas chromatography (GC) and GC-mass spectrometry resulted in the identification of 58 and 28 compounds, respectively, from the two systems. Furans were the main reaction products in both systems and 2-furfural alone comprised 522 and 999 g kg^?1 of the volatiles, respectively, from the systems with final pH values of 5–0 and 2–6. Maintaining the pH at 5–0 resulted in a higher yield and greater numbers of nitrogen-containing compounds, and monocyclic pyrroles, pyridines and 2,3-dihydro-l H-pyrrolizines were identified only in that system. Aliphatic compounds, alicyclic compounds, benzene derivatives. l-(2–furfuryl)pyrroles and pyrazines were also identified. This investigation is the first report of the formation of 2.3-dihydro-l H-pyrrolizines in a model system containing lysine as the amino compound; a possible mechanism is proposed.     

Study of the beta -delayed neutron decay of 18N

The shortage of suitable liver donors for children has motivated the use of ABO-incompatible (ABO-I) grafts for transplantation in urgent situations. However, survival after ABO-I liver grafts has been reported at about 30% as compared with 80% in cases of ABO-identical or -compatible liver grafts. This difference has been attributed to antibody-mediated, hyperacute or chronic liver rejection, due to preformed ABO antibodies (alloantibodies). In this study, we report our results with ABO-I livers in children without alloantibodies at the time of transplantation. From January 1988 to June 1993, 143 OLT were performed in 122 children. Eight children received 8 ABO-I liver grafts. Of these, 7 patients were included in the study. All 7 were alloantibody free before OLT. Five children were spontaneously alloantibody free, while in 2 children, the plasma alloantibodies were eliminated before and after transplantation using intravenous infusion of specific blood group antigens of the donor blood group (soluble antigens). Immunosuppression consisted of a triple-drug treatment combining CsA, AZA, and steroids. The follow-up period was between 10 and 48 months. One child died from a surgical complication. Six children survived, but 1 died 10 months later from intestinal obstruction. There were no graft losses and no episodes of hyperacute or chronic rejection. The graft and patient survival rate was 71%. There was a 28% incidence of rejection, but all were mild (requiring steroid boluses only). Our results suggest that the absence of ABO alloantibodies at the time of and after transplantation can protect ABO-I liver grafts against antibody-mediated rejection, whether hyperacute or chronic, and that soluble antigens are effective in eliminating alloantibodies in children.     

Optimal synthesis of tunable elastic wave-guides

Topology optimization, or control in the coefficients of partial differential equations, has been successfully utilized for designing wave-guides with precisely tailored functionalities. For many applications it would be desirable to have the possibility of drastically altering the wave-guiding properties of a device “on the fly,” in a controllable manner as an influence of some external input. This would enable wave-guides with highly non-linear input-output mappings, such as for example controllable wave switches.In this paper, we propose using finite elastic pre-straining for the purpose of tuning a wave-guide. In order to systematically formulate and solve the wave-guide synthesis problems we utilize mathematical programming methods in conjunction with topology optimization for parametrizing the design space. The resulting extremal problem is, from a practical point, equivalent to finding an optimal subdivision of a given control volume into two disjoint subsets occupied by two different materials, normally resulting in a highly heterogeneous elastic body with desired wave-guiding functionalities in the original and finitely deformed configurations.The proposed methodology is illustrated with numerical examples.     

Neutron Scattering and Ordering of Nuclear Spins

The ordering of nuclear spins takes place at extremely low temperatures because of the weakness of the interactions between their magnetic moments. Neutron scattering is the traditional and unique method to study the collective ordering of magnetic moments. The combination of the problem (nuclear spin ordering) and the method (neutron scattering) leads to new insight into the many body behaviour of the nuclear spin system and into some of the long standing general questions of the cooperative behaviour of magnetic systems. We describe neutron scattering studies on the nuclear spin systems in Cu and Ag at nano- and subnanokelvin temperatures as an example of a very successful international collaboration based on the work performed at the Low Temperature Laboratory, in the Helsinki University of Technology in Otaniemi. The collaboration was initiated by Olli V. Lounasmaa.     

Copper and zinc removal from roof runoff: from research to full-scale adsorber systems.

Large, uncoated copper and zinc roofs cause environmental problems if their runoff is infiltrated into the underground or discharged into receiving waters. Since source control is not always feasible, barrier systems for efficient copper and zinc removal are recommended in Switzerland. During the last few years, research carried out in order to test the performance of GIH-calcite adsorber filters as a barrier system. Adsorption and mass transport processes were assessed and described in a mathematical model. However, this model is not suitable for practical design, because it does not give explicit access to design parameters such as adsorber diameter and adsorber bed depth. Therefore, for e.g. engineers, an easy to use design guideline for GIH-calcite adsorber systems was developed, mainly based on the mathematical model. The core of this guideline is the design of the depth of the GIH-calcite adsorber layer. The depth is calculated by adding up the GIH depth for sorption equilibrium and the depth for the mass transfer zone (MTZ). Additionally, the arrangement of other adsorber system components such as particle separation and retention volume was considered in the guideline. Investigations of a full-scale adsorber confirm the successful application of this newly developed design guideline for the application of GIH-calcite adsorber systems in practice.