bluuebunny/crossref_metadata_2025 huggingface dataset:
Wissenschaftlichtechnische Fachgesellschaften in sich verändernden Umwelten
Authors: Staudt Wolfgang
Published: December 2004

Scientific and Technical Societies in Changing Environments. The role of science and technology has been subject to change during the development of modern societies. The application of scientific knowledge and technological innovations is now taken for granted in many sectors of society. Yet the scientific and technological transformation of modern society is not proceeding without conflict. As a result, science and technology have become political issues. Members of society no longer unquestioningly accept the scientific and technical changes to their way of life and work; instead they wish to exert a modifying and limiting influence on developments. Demands arise for orientation of research towards the needs of society. Traditional autonomy is required to make way for a responsible utilisation of the possibilities of science and technology. This article attempts to establish the role of learned societies in dealing with these problems.
Entwicklung von technischen Katalysatoren
Authors: Gallei Ewald F. , Neumann Hans‐Peter
Published: December 2004

Development of Industrial Catalysts. This paper considers the industrial development of catalysts as an important component of chemical processes. Starting from the desired properties, a detailed description is presented of the heterogeneous catalysts which account for some 80% of all the catalyst systems in industrial use. In addition to an treatment of catalyst structure, particular emphasis is placed on interdisciplinary aspects of catalyst development. The factors influencing catalyst performance and the range of methods used for their characterisation are also discussed. The approach adopted in catalyst development is then presented and four topical examples are given to illustrate the influence of structural parameters on catalyst performance. The article concludes with a description of the industrial production of catalysts and a look at the future of catalyst development.
Entwicklungsstand der Alkalichlorid‐Elektrolyse. Teil 2: Elektrochemische Größen, wirtschaftliche Fragen
Authors: Bergner Dieter
Published: December 2004

State of Development of Alkali Chloride Electrolysis (II). Electrochemical Quantities, Economics. The first part of this rewiew article described cells, membranes, electrolytes and products of the membrane cell process. The second part, presented below, deals with cell voltages, current efficiences and energy consumption, as well as with plant construction and plant conversion with membrane cells. A brief look at the connection between the discussion on chlorine chemistry and the introduction of the membrane cell process concludes this review.
Ausgewählte Problempunkte bei Simulation und Gestaltung rektifikativer Trennprozesse
Authors: Scholl Stephan , Polt Axel , Krüger Siegfried
Published: December 2004

Selected Problem Points in the Simulation and Design of Distillative Separation Processes. Thermodynamic simulation represents an important tool in the process engineering treatment of distillative separation processes. The degree of detail in the representation of the real process is orientated upon the question of the stage of process development at which thermodynamic simulation is utilized. For three examples of practical relevance it is shown that an improper representation of process reality in the simulation may lead to ambiguous and even false interpretations. In most cases problems arise when process‐relevant functions of single units are not incorporated adequately. It is shown that a Langrange‐type consideration of the process avoids most of the problems discussed.
Strategie für eine Konversion der Chlorchemie
Authors: Plinke Eckhard , Schüssler Reinhard , Kämpf Klaus , Darimont Thomas
Published: December 2004

Strategy for Conversion of Chlorine Chemistry. After years of discussion about „cessation of chlorine chemistry”︁, the study entitled „Conversion of Chlorine Chemistry”︁ [1] commissioned by the Environmental Ministry of the State of Hesse in Germany and undertaken by Prognos AG provides the very first detailed comparative ecological and economical assessment of production process and products of „chlorine chemistry”︁ and industrially feasible alternatives and presents a strategy for partial transformation. This accomplished on the basis of a systematic assessment of risks and benefits, as demanded by the Geman parliametary commission „Protection of Humankind and the Environment”︁.
Stationäre Chemische Energieumwandlung als Herausforderungen für den Verfahrensingenieur
Authors: Fischer Manfred , Köhne Rainer , Schnurnberger Werner , Tamme Rainer
Published: December 2004

Meeting future energy demands with more efficient, lower emission, and safe energy technologies has top priority in the medium term. Consumer‐friendly energy concepts, integrated into regional and supraregional energy supply structures, represent further elements. These will make important contributions to resource‐conserving and environmentally compatible power supplies utilizing local energy sources including renewable resources. Supplying energy to large areas involves additional tasks, from compensation of large amounts of fluctuating energy to the transport of fluctuating energy to the transport of renewable energy over long distances. Solar dish, parabolic section, and tower power generating plant have considerable economic and CO2‐reduction potential in sunny countries, such as in the Mediterranean region, However, the costs of solar‐thermal electricity generation have to be reduced by a factor of 1.5 to 2. Fuel cell systems can attain particular significance as efficient low‐emission energy conversion systems in power plant and automative engineering once their technical and economic potential can be realized.
Fahrzeugantrieb mit PEM‐Brennstoffzelle
Authors: Klaiber Thomas
Published: December 2004

In the areas of traffic and vehicle power units, high energy consumption an resource depletion have led during the past twenty years to improvements to vehicles with Diesel and Otto enigines, improved traffic control, and the development and introduction of alternative power units. One alternative is the fuel cell motor. The advantages of a fuel cell vehicle lie in reduced or zero emission. The electrical efficiency of the fuel cell is very high and not subject to the constraints of the Carnot process. Owing to their technical properties, such as their working temperature range, CO2 compatibility, solid electrolyte in the form of a film, PEM fuel cells appear most suitable for use in vehicles. They can be operated fairly straightforwardly so that the periphery remains well controllable on construction of a complete system. If an alternative power unit such as the fuel cell is to acquire customer acceptance beyond initial niche applications then not only better primary energy consumption and significantly better emmision behavior than conventional drives are required. Further technical an economic demand will have to be meet in order satisfy sutomer expectations.
EU‐Öko‐Audit‐Verordnung und produktions‐integrierter Umweltschutz am Beispiel der Lebensmittelindustrie
Authors: Chmiel Horst
Published: December 2004

The eco audit directive of the Europen Union (EEC 1836/93) requires that a company applying for certification should lay open its environmental policy, install enviromental management, and conduct an internal environmental analysis. It can be demonstrated that the investments required to eliminate weak points is often recovered within a few years owing to savings relating to energy and fresh an waste water. The same can be expected for other sectors of industry. A prerequisite is a holistic approach and integration of the measures adopted into the production line. Selective separation processes play a special role in practical application of the information acquired.
Der Dialog zwischen Hochschule und Industrie im GVC‐Fachausschuß „Partikelabscheidung‐Abgasreinigung”︁
Authors: Bueb Michael
Published: December 2004

In spite of industrial growth in the western states of the Federal Republic of Germany, considerable advances have been made in clean air maintenance since the 1950s. Contributions came from improved waste air purification processes, appropriate legislation, and a broad‐based industrial implementation of primary and additive measures for waste gas avoidance or purification. Particularly in the area of environmental protection, the need for constructive collaboration between the state, university research, and industry is very clear. Knowledge gained from fundamental research at universities is an important resource for industry, particularly when such university research stays mindful of the problem solutions and innovations required in practice. At the Institute for Mechanical Process Engineering and Mechanics at the University of Karlsruhe a number of very important and fundamental research projects in the area of particle separation and waste gas purification were undertaken in recent years by F. LÖFFLER and coworkers. These clearly show how appropriate fundamental research work can provide valuable contributions to the understanding and further development of processes. As Chairman of the GVC Specialist Committee „Particle Separation – Exhaust Gas Purification”︁ for many years, F. LÖFFLER made exemplary contributions to a successfull dialogue between university research and industry.
Verbesserung der Entscheidungs‐findung bei der Produktionssteuerung eines erdölverarbeitenden Anlagenkomplexes
Authors: Peuker Thomas , Hartmann Klaus
Published: December 2004

Die erdölverarbeitende Industrie ist durch große verfahrenstechnische Anlagenkomplexe gekennzeichnet. Der Betrieb dieser erfordert im Rahmen der Produktionssteuerung Entscheidungen, um das Produktionsziel optimal zu erreichen. Dem Entscheidungsträger soll ein Hilfsmittel zur Verfügung gestellt werden, das der Komplexität des Problems gerecht wird und ihn bei der Entscheidungsfindung unterstützt.
Strömungsverhalten wäßriger Schizophyllanlösungen in Kugelpackungen
Authors: Müller Markus , Brunn Peter Otto
Published: December 2004

Schizophyllan ist ein Ausscheidungsprodukt des Pilzes Schizophyllum commune, was nur Glucose als Monomer hat. In Abb. 1 ist die molekulare Primärstruktur des Monomers dargestellt [1]. Die Monomehrzahl n in diesem extrazellulären Polymer beträgt zwischen 9000 und 38 000. In wäßrigen Lösungen liegt es nach YANAKI et al. [2] als stäbchenförmige Tripelhelix vor. Erste Anwendungen mit diesem Biopolymer fanden in der Medizin zur Tumorbekämpfung Einzug [2]. RAU und HAARSTRICK [1, 3] untersuchten den Einsatz als Widerstandsverminderer bei turbulenten Strömungen und die Anwendung als Flutungshilfsmittel unter der Berücksichtigung hoher Temperaturen und Salzgehalten. Bei dieser letztgenanten Arbeit wurde aber lediglich das Filtrationsverhalten und die Scherviskosität untersucht. Aussagen über die Strömungen innerhalb von Schüttungen wurden keine getroffen.
Quality Engineering mit statistischer Versuchsmethodik
Authors: Soravia Sergio
Published: December 2004

The strategic orientation towards a modern and widely demanded quality management is said to be substantial for reaching and maintaining competitiveness. Methods and tools to realize related objectives such as quality improvement, cost reduction, and shortening of development periods are often only known by name. However, there are frequently no or only vague ideas about their concrete contents and how they can be used in practice. One of the most efficient techniques of Quality Engineering is the methodology of statistical experimental design (DoE, Design of Experiments). The determination of optimal and robust product characteristics and process conditions, especially before starting large‐scale production, increases process capability/safety and therefore improves product quality. All considered experimental parameters are varied in a systematic and balanced way so that a maximum of information and knowledge is gained from the analysis of the experimental results. The intention of this paper is to give an insight into essential principles and possible industrial applications of experimental design by means of examples and completed projects without entering into mathematical and statistical details.
Leckageraten von Dichtungen für Flanschverbindungen: Einflußgrößen, Anforderungen, meßtechnische Erfassung und leckageratenbezogene Dichtungskennwerte
Authors: Kockelmann Hans
Published: December 2004

Flow theories can help in determining the fundamental interrelationships between the leak rate of gaskets for flange connections and the relevant influencing parameters. The basic rule for the transfer of results obtained for special boundary conditions to other conditions can be derived. In this way the effort involved in gasket testing can be reduced. This paper gives the interrelations between the leak rate of gaskets on the one hand and the internal pressure, the temperature, the medium, and the gasket thickness on the other and discusses them with aid of measured results. The effect of the gasket stress and thickness can be determined only of experimental investigations. Furthermore, the requirements placed on gaskets, the leak rate related gasket characteristics defined in various standards and the measuring techniques for their determination are discussed.
Wärmetechnische Optimierung eines Chemiestandortes
Authors: Wolff Andreas , Groebel Markus , Janowsky Ralf
Published: December 2004

Ausgangspunkt für die wärmetechnische Optimierung eines Chemie‐standortes sind die Pinch‐Analysen der wichtigsten Anlagen. Häfiges An‐ und Abfahren sowie ständige Lastwechsel erschweren die Durchführung einer Total‐site‐Analyse. Aus diesem Grunde und wegen der stofflichen Kopplung von Energieversorgungssystemen und Anlagen ist die Entwicklung eines Standortmodells erforderlich. Aufgrund der Flexibilität des Modells läßt sich ein Programm erstellen, das als Analyse‐ und Planungsinstrument einsetzbar ist. Dieser Beitrag beschreibt das zugrundeliegende Modell und zeigt, wie durch den Einsatz des Programms technisch realisierbare Einsparpotentiale aufgezeigt werden können.
Phasengrenzflächen in Blasenströmungen — Teil 2: Großblasen und Pfropfen
Authors: Millies Marco , Mewes Dieter
Published: December 2004

In the first part of this article an equation was derived for calculation of the specific interfacial are and the size distribution of bubbles in bubble flow. However, its application is limited to gas contents lower than 12%. At higher gas contents, large bubbles and gas plugs occur in the field of flow. These have a very low interfacial area per unit volume compared to small bubbles. Since large bubbles and gas plugs contain a large proportion of the gas in the flow, the overall interfacial area is reduced. In the present contribution, the gas content above which large bubbles and gas plugs occur is calculated. The results are subjected to experimental testing for vertical pipe flow. In addition, the volume fraction of the larger bubbles is calculated and the results verified experimentally by measurements in bubble columns. Subsequently, the specific enterfacial area with and without large bubbles is calculated for high gas contents. The results are in agreement with values measured for bubble columns and column plates.
Vergleich der Effektivität von bewehrten und unbewehrten Rührsystemen in der chemischen Verfahrenstechnik
Authors: Markopoulos Joannis
Published: December 2004

In spite of the fact that vortex formation, in unbaffled agitated vessels, is in most cases an undesirable phenomenon, many cases exist in chemical engineering where unbaffled systems can be used with greater effectivness than systems with baffles, at the same or even smaller energy consumption levels. Satisfactory results can also be obtained in unbaffled agitatated vessels without an air‐liquid interface. These facts, viewed in the light of energy problems in the chemical industry, show the current importance of comparative studies of baffled and unbaffled systems. In the present review article some characteristic cases from the fields of fluid dynamics, homogeneous distribution processes, suspensions, as well as mass‐transfer and heat‐transfer operations in baffled and unbaffled agitated vessels are presented and comparatively discussed in relation to their effectivness.
Entwicklungstendenzen in der Feststoff‐verfahrenstechnik
Authors: Peukert Wolfgang
Published: December 2004

This paper describes trends in the field of particle technology. The properties of dispersed matter which has to be handled in the chemical engineering processes or which has to be produced are of decisive importance. Future trends can be characterized by improvement of existing technologies, by a better understanding of fundamentals, combination of principles, extension of process parameters, process control and simulation, and new processes. An important trend is the production and handling of finer particles. Traditional methods of comminution and classification reach their limit around 1 μm. New processes for synthesis of particles by physical and chemical methods appear to becoming more popular. Nano‐sized particles may become of future relevance in various fields of technology such as material science, micro electronics or medicine.
Entwicklung membranunterstützter Reaktionsprozesse
Authors: Schirg Peter , Waldburger Raoul M. , Widmer Fritz
Published: December 2004

The use of membrane technology is developping from the solely work‐up of product and waste streams all the way to integration into processes. The membrane reactor offers, by analogy with biological cells, great possibilities for product‐integrated environmental protection. Two principal areas of application of membranes in reactors are becoming apparent. Use for removal of products or by‐products from bioreactors and the coupling with chemical reactions considered in this article. The first such membrane reactors served for the removal of water from esterification reaction mixtures. Significant advances for membrane reactor technology came with the recent development of membranes of enhanced selectivity and flow density as well as improved thermal and chemical stability. In addition to the availability of high‐performance membranes, fundamental knowledge and methods are required to assure efficient reaction‐engineering utilization of membrane reactors. This paper discusses fundamental concepts relating to the use of various membrane reactors in parallel, consecutive, and equilibrium reactions. In general, in the case of membrane‐supported parallel reactions, controlled addition of reactant can raise the reaction selectivity. Selective removal of primary and side products from consecutive or equilibrium reactions can increase yields. Comparison of membrane‐supported reactor types (batch, loop, and plug‐flow membrane reactors) indicate that the membrane‐supported loop reactor will prove most effective in the majority of cases thanks to its pronounced flexibility.
Fortschritte in der Adsorptionstechnologie
Authors: Rafflenbeul Rolf
Published: December 2004

The high purchasing price of organic solvents has stimulated interest in their recovery from emissions. While conventional adsorption units for recovery of monosolvents have been in industrial use for some 70 years, it has hitherto proved impossible to costeffectively desorb solvent fractions sufficiently pure for direct use in the case of emissions of mixtures. The solvent mixtures obtained by desorption had to be separated in expensive rectification steps, with the high costs thus precluding widespread use of adsorption for recovery projects in the chemical and printing industries. After conclusion of development work performed in the USA and Germany over a period of 10 years, it is now possible to control the adsorption steps in such a way that the purities necessary for reutilisation of the individual solvent fractions can be attained without the aid of rectification steps.
Rauchgasreinigung mit Reststoffbehandlung und Wertstoffgewinnung in der Abfallverbrennung — Stand und Tendenzen
Authors: Schaub Georg
Published: December 2004

The design of flue gas treatment equipment in municipal waste incineration plants worldwide varies according to the requirements with respect to pollutant emissions and resource recovery. Various combinations of individual separation processes may be encountered, such as dry particle separation, gas absorption (wet or dry), adsorption, catalytic or thermal conversion. The present comparison of different basic process alternatives indicates that firstly any degree of pollutant removal can be achieved by the available process technologies with corresponding expenditure of money and energy demand, secondly, German plants generally are more complex than plants in other countries due to more stringent separation and resource recovery efficiency requirements, and thirdly, a trend can presently be seen towards more simple and cheaper processes with simultaneous separation of several pollutants in one process step.
Modelluntersuchungen zur Partikelbeanspruchung in Reaktoren
Authors: Henzler Hans‐Jürgen , Biedermann Anja
Published: December 2004

This paper reports systematic studies on hydrodynamic stress in agitated vessels with baffles, reactors with predominantly laminar flow, SERALE viscosimeters, bubble columns, and gas‐driven loop reactors. The stress on particles is determined by way of the destruction of model particle systems, with the kinetics of destruction, the equilibrium particle diameters, and the enzyme activity after a given time serving, respectively, for assessment of the stress. Thereof one obtaines an indication of the methodology necessary for determining the stress and it permits selection of appropriate reactor systems according to the criterion of particle stress. In the case of reactors with turbulent motion without dominant laminar flow or gas/liquid interfaces give analogous results, permitting the assumption that they are also applicable to other particle systems. Specifically for stirred reactors a geometric function is derived from the experimental results which permits prediction of stress caused by various types of impellers. Impellers with large blade areas relative to the dimensions of the tank produce less shearing forces owing to their uniform power input, in contrast to small and especially axial flow impellers. In laminar flow or reactors with gas/liquid interfaces the level of particle stress depends upon the proclivity of the particles to enter the boundary layers. It can therefore be deduced that particles with different surface properties, which lead to differing interactions with boundary layers and interfaces, will also experience different kinds of particle stress on laminar flow or in aeration processes. Thus the scope for application of the results obtained with model particle systems to other particle systems is limited in such reactors.
Computerunterstützungen für Planung und Steuerung in der Fertigungstechnik und in der Prozeßindustrie
Authors: Jänicke Winfried
Published: December 2004

This contribution is concerned with computer support in the planning and execution of production with regard to the chemical industry. It examines the question whether strategies and software from production engineering can also be used in the processing industry and the extent to which chemically specific supplementation is necessary.
Korrelation physikalischer mit anwendungs‐technischen Größen bei Dispersionen
Authors: Lent Boudewijn Van , Klinksiek Bernd
Published: December 2004

This review shows the relationship which exists between certain applications related and physical properties of dispersions. It also presents the possibilities at our disposal for determining such properties and influencing them in a desired manner. However, the available knowledge and methods are not sufficient for complete prediction of applications‐related properties. Gaps in our knowledge and in the experimental possibilities are indicated. What is feasible is demonstrated with the aid of some typical examples. The example are selected so that certain properties of the dispersions, such as particle size, rheological behaviour, or charge behaviour exert a pronounced influence on the applications‐related properties. The examples cover various material systems, such as emulsions, polymer dispersions, dispersions of active principles, and inoganic pigments. In conclusion, the article considers what knowledge and methods will be required in the future for more purooseful product develooment.
Vergleich verschiedener verfahrenstechnischer Konzepte der präparativen Flüssigchromatographie
Authors: Heuer Christian , Kniep Hagen , Falk Thomas , Seidel‐Morgenstern Andreas
Published: December 2004

Liquid chromatography utilising porous solid phases (adsorption chromatography) is one of the most powerful and versatile methods of modern analytical chemistry. Its widespread application is due in part to the development of a broad range of combinations of solid stationary and liquid mobile phase. Normal phase and reverse phase chromatography with pure and chemically modified silica gel, respectively, affinity chromatography, and ion chromatography can be cited as examples [1]. In addition to its use as an analytical method, chromatography is becoming increasingly important in the preparative‐scale isolation of pure substances in the pharmaceutical industry, in biotechnology, and in the production of fine chemicals. In many cases, the required purity criteria can only be met with chromatographic techniques, as in the resolution of racemates. From a process engineering viewpoint, a better understanding of concentration profile deformations caused by intended overloading of separation columns has recently been acquired [2]. In particular, this cncerns the description of displacement and entrainment effects associated with the competing adsorption. A series of alternative operating modes has been developed and used [3] for enhancing yields and productivities. In spite of a number of attempted comparative studies [4] there is a lack of quantitative information about optimized process. This article aims to compare four different process engineering concepts of preparative chromatography on the basis of a uniform theoretical model.
Umsetzung des Gewässerschutzes in der Praxis bei Instandhaltungs‐ und Reinigungsarbeiten an Chemieanlagen
Authors: Eipper Gunter
Published: December 2004

The water management law (WHG) and the plant regulations of the German federal states stipulate boundary conditions which must be observed during work on plants handling substances which are hazardous to water. There are various possibilities for the implementation of the legal provisions. During maintenance and cleaning work on chemical plants, our aim must be to provide effective protection of our waterways and to ensure that the operating procedures are also efficient in economic terms. Procedures which have been tried and tested in practice are described. The annex gives a compilation and explanations of extracts from legal texts from the field of water legislation which are of relevance in carrying out such work.
Anwendung von Magnéli‐Phasen des Titandioxids in der elektrochemischen Technologie
Authors: Zweynert M. , Döring H. , Garche Jürgen , Enghardt K. , Wiesener K.
Published: December 2004

Use of Magneli Phases of Titanium Diooxide in Electrochemical Technology. Magneli phases of titanium oxides are known to have many interesting properties such as a conductivity comparable to that of graphite, a high level of chemical stability, and large overpotentials for gas evolving reactions. In this paper the possibilities for synthesis of pure Magneli phases are reported and the influence of various experimental parameters on the electrochemical properties is discussed. Several chemical, electrochemical, physicochemical, and physical experiments were performed. The opportunities for technological applications in the field of electroplating, in the recycling of process solutions, as supporting substrates for electrocatalysts, and as collector materials are considered.
3D‐Geometriebestimmung in Industrieanlagen
Authors: Rieks Hans‐Joachim
Published: December 2004

3D‐Geometry Determination in Industrial Plant.

Nowadays, chemical and other industrial process plant is expected to meet increasingly stringent demands with respect to performance parameters and service life. Exact knowledge and comprehensive documentation of plants are of increasing significance in the various tasks involved in their operation, maintenance, modification and expansion. In developing this documentation, industrial measuring systems and the process of close‐range photogrammetry are the ideal tools for an appropriate determination of 3D geometry, yielding results which are suitable for many applications. A distinction is made between the highly accurate determination of the dimensions of special components and the actual as‐built plant documentation pertaining to larger plant segments or entire plants. A detailed description of the framework conditions and the processes of determining 3D geometry in industrial plant can be found in the VGB bulletin of the same title [1].
Absicherung von Zulaufreaktoren durch Überwachung der Reaktantenakkumulation mittels On‐line‐Energiebilanzierung
Authors: Schimetzek Ralf , Giesbrecht Hartmut
Published: December 2004

Safe Operation of Semi‐Batch Reactors by Supervising the Accumulation of Reactants Through Online Energy Balance.

An essential part of the strategy for ensuring safe operating conditions for semi‐batch reactors is the permanent guarantee of an admissible accumulation of reactants. Thus, even in case of a failure or a breakdown of the cooling system or the agitator, the maximum possible pressure and temperature in the reactor still remain within their permissible limits. The energy balance method makes it possible to monitor online the reactant concentration and to limit the accumulation by switching off the feed of reactant in time. Practical experience with a production plant is presented in which, over a period of 2 years, numerous process cycles were calculated and subjected to comparative analysis. The results show that the reproducibility as well as the accuracy of calculation are high and that the energy balance method can be regarded as reliable. In addition, recommendations for the implementation of this safety strategy as a reliable tool in plants are obtained. On this basis, the energy balance method provides additional information about the process and, thus, can provide an increase of plant safety and product quality by maintaining process availability.
Einsatz von Biocompounds zum Abbau chlorierter Kohlenwasserstoffe in der Grund‐ und Abwasserreinigung
Authors: Briesovsky Annett , Jank Manfred , Köser Heinz , Schnabel Rainer
Published: December 2004

Use of Biocompounds for Degradation of Chlorinated Hydrocarbons in Treatment of Ground Water and Waste Water.

Process engineering approaches to waste water treatment using immobilised microorganisms (MO) permit greater biomass concentrations in the bioreactor and hence higher conversions per unit time. Moreover, the biofilms formed assure favourable conditions for degradation specialists. Immobilisation of microorganisms is feasible on both static and freely mobile supports. Use of the latter permits modification of the flow conditions in the reactor.
Twin boundaries as crack nucleation sites
Authors: Blochwitz C. , Tirschler W.
Published: December 2004

Coherent twin boundaries (TBs) in f.c.c. metals are considered to have low energy. Nevertheless, even TBs are preferred sites for crack nucleation in materials loaded at very small alternating plastic strain amplitudes (high cycle fatigue). In the present paper, the mechanism of short crack propagation starting from TBs was studied for medium amplitudes and described taking into account both elastic and plastic anisotropy effects. A strong dependence of the TB crack density on the meso‐texture of the material was found. The twin part of the meso‐texture was described by the <111> rotation vectors of the TBs observed using the EBSD technique in the SEM. The rotation vectors of the damaged TBs were arranged in a “damaging cone” around the specimen axis. The risk of TB cracks in texturized rolling plates can be reduced by a favourable alignment of the specimen in the rolling plate avoiding the damaging cone of rotation vectors. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Material analysis with X‐ray microdiffraction
Authors: Friedel F. , Winkler U. , Holtz B. , Seyrich R. , Ullrich H.‐J.
Published: December 2004

Steel has continued to develop its status as a lightweight construction material for the design of vehicle bodies, most recently with the development of multi‐phase steel. With a specific mixture of different phases in the steel microstructure, multi‐phase steel combines high stability with good forming capacity. The characterisation of the complex structure of the multi‐phase steel represents a challenge for metallurgists. For some years a new generation of X‐ray diffractometers with two‐dimensional (area) detectors and apparatus for local dissolved measurements are available to customers [5]. This paper reports the applications and advantages of the modern X‐ray diffractometry method. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Clinical significance of monoclonal B cells in cerebrospinal fluid
Authors: Nowakowski Grzegorz S. , Call Timothy G. , Morice William G. , Kurtin Paul J. , Cook Rachel J. , Zent Clive S.
Published: December 2004

Background

Morphologically malignant lymphocytes in the cerebrospinal fluid (CSF) are highly suggestive of central nervous system involvement by lymphoid malignancy. Although flow cytometry is increasingly used to detect a monoclonal B‐cell population in the CSF, the significance of this finding in the absence of morphologically identifiable malignant cells is unknown.

Methods

We reviewed CSF flow cytometric results in 32 patients studied at a single institution over 5 years and identified patients who had monoclonal B‐cells in the CSF. Clinical presentation and course were reviewed.

Results

Twelve patients had a monoclonal B‐cell population in the CSF, but only three had clinical evidence of malignant CNS disease. Of the other nine patients, 4 had nonmalignant neurologic disease and five had a lymphoproliferative disorder: chronic lymphocytic leukemia (n = 4) and mantle cell lymphoma (n = 1). In patients who had chronic lymphocytic leukemia and mantle cell lymphoma, the monoclonal B‐cell population was small and had an immunophenotype identical to that of circulating malignant B cells. None of these nine patients developed clinical evidence of malignant CNS involvement during follow‐up.

Conclusion

In patients who have indolent B‐cell malignancies, the presence of monoclonal B cells in the CSF may not be diagnostic of clinically significant CNS involvement by a lymphoid malignancy. © 2004 Wiley‐Liss, Inc.
The oxidative pyrolysis of plastics
Authors: Edgerley Peter G.
Published: December 2004

Experiments using a thermobalance, a hot‐plate and a moving furnace have all shown that polymers can evolve oxidation products in air even at moderate temperatures. These gases can include carbon monoxide, formaldehyde and acrolein. The amounts are generally low except near the very top of the temperature range used in some processes. Tests in the vicinity of three different extruders have confirmed some of these small‐scale findings but also showed that the evolved gases were adequately handled by the ventilation installed. The evolution of other gases in certain cases has also been briefly studied. Some measure of the heat evolved in oxidative pyrolysis has also been obtained for polyethylene. The polymers investigated were low density and high density polyethylene, poly(ethylene vinylacetate), polypropylene, poly(vinylonitrille) polypropylene, poly(vinylchloride), polystyrene, poly(methylmethacrylate), polycarbonate, poly(ethylene terephthalate), nylon 6‐6, acrylonitrile/butadiene/styrene and one nature material (wood).
An analysis of smoldering fires in closed compartments and their hazard due to carbon monoxide
Authors: Quintiere J. G. , Birky M. , Macdonald F. , Smith G.
Published: December 2004

A review was made of smoldering fire experiments conducted in closed rooms and buildings. The results were summarized by tabulating maximum levels of CO, the time integral of CO concentration (‘dose’), CO2, temperature rise and oxygen consumption. A hazard time based on the attainment of a CO dose equal to 4.5% CO‐minutes and the time for transition to flaming were also tabulated. The likelihood of reaching a critical CO condition during smoldering seems to be comparable with the likelihood of having transition to flaming occur. A theoretical model, requiring inputs of CO production rate and energy release rate, was executed and compared with available data. The theoretical results for CO concentration as a function of time were in good agreement with the experimental data. The model offers a means of extrapolating test data to compartments of various size in order to assess the general hazard of CO due to smoldering.
Smoke formation from burning polystyrene and its suppression
Authors: Chalabi R. , Cullis C. F.
Published: December 2004

Studies have been made of the influence on smoke generation from polystyrene of the incorporation of a number of apparently inert solids, the smoke‐producing tendency being expressed in terms of the maximum specific optical density of smoke per unit weight of polymer consumed. Of the compounds investigated, by far the most efficient smoke suppressant is pyrogenic silica, the effect of which is, over a wide range, directly proportional to the total surface area of the material introduced. Examination of partially burned polystyrene‐pyrogenic silica composites reveals the presence at the surface of a hard rigid skin, which is not observer with polystyrene alone of with polymer samples containing other additives. The formation of a protective skin is also indicated by the kinetics of forced burning of these composites where the weight loss is a linear function of log time and by measurements of the rate of change of thickness of polymer samples during combustion. Thermogravimetric experiments in which polystyrene and pyrogenic silica are heated in contact with one another show that the silica encourages the formation of a carbon residue from the polymer. A mechanism of skin production is proposed which involves the build‐up of layers of tangential spherical silica particles cemented together by cross‐linked polystyrene.
Thermal degradation studies of molybdenum containing polyester thermosets
Authors: Das M. , Haines P. J. , Lever T. J. , Skinner G. A.
Published: December 2004

A study has been made of the effect of molybdenum trioxide on the thermal degradation of a series of chlorinated and brominated polyester thermosets. Like antimony oxide, it showed flame retardant activity in all the halogenated polyesters. It was shown to affect the char yield, and the temperature and weight loss of each degradation step. X‐Ray diffraction studies of the degraded dibromoneopentyl glycol polyesters showed that in air a near‐quantitative yield of molybdenum trioxide was present above 550 °C. Some dioxide was present before the final char oxidation step occurred. In a nitrogen atmoshphere the trioxide was reduced to the dioxide at first, but this finally reacted to give the carbide at around 900 °C. Infrared spectroscopy showed that inclusion of the molybdenum trioxide resulted in structural changes in the high‐temperature polyester residues which were more prominent when bromine was present. Elemental analysis of the residues indicated that the presence of the trioxide in the brominated polyesters accelerated the release of bromine at high temperatures and confirmed its char‐promoting tendencies.
Fire deaths in the United Kingdom 1976‐82
Authors: Anderson R. A. , Willetts P. , Harland W. A.
Published: December 2004

A study of fire deaths in the Glasgow area has been extended to the rest of the United Kingdom in order to assess the applicability of the conclusions reached in the Glasgow study to the whole country. With assistance from pathologists in a number of other areas, 71 cases were included in the study, covering both pathology and toxicology of the deaths where possible. In both the Glasgow and UK studies, most of the fire deaths occurred in dwelling‐house fires. These and other demographic characteristics were in agreement with national fire statistics. The principal features of pathology in this study were burns (79 per cent of cases), respiratory system injury (72 per cent of cases) and soot deposition in the respiratory tract (96 per cent of cases), and these reflected a similar incidence in Glasgow study. Carbon monoxide was considered to be the cause of death in 51 per cent of the deaths in this study and to be implicated in the death of 37 per cent of the other cases (54 per cent and 31 per cent respectively in Glasgow). Cyanide was estimated to be a significant factor in 33 per cent of the deaths in the UK study (24 per cent in Glasgow). Alcoholic intoxication was found to be a significant additional factor in Glasgow but was much less prominent in the other areas of the UK. It concluded that, with the exception of alcohol, the results of the Glasgow study are valid for the UK as a whole.
Fire behaviour of upholstered furniture—an experimental study
Authors: Andersson B. , Magnusson S. E.
Published: December 2004

A series of experiments for studies of flammability characteristics of upholstered furniture is presented. The series comprises 53 experiments on a reduced scale and 11 full‐scale experiments in an extensively instrumented room. Results are presented from measurements of rate of heat release and smoke production. The experiments indicate that ignitability can be considerably decreased by careful choice of the upholstery materials.
Toxic gas and smoke measurement with the British Fire Propagation test. I: Test conditions
Authors: Brown S. K. , Martin K. G.
Published: December 2004

No standard method has been developed for measureing the evolution of specific toxic gases from building lings when involved in fire. The British Fire Propagation test (BS 476 Part 6) operated in an instrumented room has been proposed for this purpose previously but has not found general acceptance. It is considered further in this report, which investigates the movement and measurement of smoke and specific fire gases under different conditions of room stirring and the effect of the latter on fire propagation indexes. Stiring has been found to have no statistically significant effect on fire propagation indexes provided that the effects of this on calibration of the apparatus are taken into account. Stirring also had little effect upon smoke production per se. Under unstire conditions smoke and toxic gases stratify in the same layer early in the test, and measurement of their production at any single room location will be subject to the location, the way the room influences stratification and how the room is instrumentee, as well as by the prpduct performance. Under stirred room conditions smoke and toxic gases are evenly distributed and product performance can be assessed more simply from concurrent measurements of fire, smoke and toxic gas parameters. The latter procedure is proposed for obtaining relative data on building linings and for examination in further studies for correlation to room and corridor burns.
Toxic gas and smoke measurement with the British Fire Propagation test. III: UPTV formulations with reduced HCl evolution
Authors: Brown S. K. , Martin K. G.
Published: December 2004

A range of basic fillers has been incorporated into UPVC formulations and assessed for effectiveness in suppressing HCl evolution and influence on other fire properties. Investigations were carried out with the British Fire Propagation test (BS 476 Part 6) in a room previously used for assessing the fire behaviour of UPVC building products. HCl evolution was also studied following degradation in a pyrolysis tube furnace. Despite notable differences in these methods of assessment, good correlation was found between them. Varying degrees of HCl suppression were obtained and for formulations containing stronger bases effectiveness was found between them. Varying degrees of HCl suppression were obtained and for formulations containing stronger bases effectiveness was approximately stoichiometric to the amount of base present. Lithium hydroxide was thus the most effective HCl absorber on a weight basis. A formulation with 40 parts per hundred resin of this filler evolved only 2% of its theoretical HCl, although at the expense of increased fire propagation indexes. Smoke properties were not greatly influenced by the formulations. Precipitated calcite was considered the most promising acid‐absorbing filler for practical use. At 40 parts per hundred resin it reduced HCl evolution to 34% of theoretical and markedly delayed the onset of incapacitating HCl concentrations in the room, with little influence on fire propagation properties of the UPVC.
The combustion products of polymeric materials. III: GC–MS Analysis of the combustion products of polyethylene, polypropylene, polystyrene and polyamide
Authors: Mitera Jiǐí , Michal Jan
Published: December 2004

A series of gas chromatographic–mass spectrometric analyses was carried out on polyethylene, polypropylene, polystyrene and polyamide in CAB 4.5 and CAB 650 chambers in the flaming and non‐flaming combustion mode. The combustion products formed were identified and used to characterize the combustion process in both chambers; procedures were selected for testing polymeric materials for the dangerous effects of their combustion products.
The composition and structure of solid char residues after thermal degradation of polystyrene, PVC and polyamide. Part I
Authors: Ševěček P. , Dvořák P.
Published: December 2004

The study of char residues after thermal degradation of synthetic polymers, especially the identification of their morphology, structure and chemical composition is presented in this paper. Special attention was focused on the polystyrene, PVC and polyamide char residues. By means of microscopy in reflected light and reflected polarized light the manifestations of optical anisotropy were observed. X‐ray analysis was used for the examination of the microstructure of PVC char residues carbonized at temperatures above 1000°C. For PVC char residues the electric resistivity was determined. The results have proved the close connection between the structure and properties of char residues and the intensity and course of thermal degradation of polymers.
The possibility of the evaluation of toxic and mutagenic effects of combustion products with the aid of Drosophila melanogaster files
Authors: Majek J. , Talapkova D. , Repka V. , Špilda I. , Košik M.
Published: December 2004

The use of Drosophila melanogaster files for testing of combustion toxicity is proposed with results from testing the effects of polyurethane combustion products.
An investigation of the flame‐retardant and smoke‐suppressant properties of tin (IV) oxide in unsaturated polyester thermosets
Authors: Cusack P. A.
Published: December 2004

Studies have been carried out of the effects of (1) anhydrous tin (IV) oxide and (2)β‐stannic acid {hydrous tin (IV) oxide} on the flammability and smoke production of unsaturated polyesters into which halogen may be introduced as a reactive monomer during the resin synthesis. The results obtained provide evidence for a marked falme‐reatedant synergism between tin and halogen, accompanied by a significant reduction in smoke from the burning polymer. The hydrous tin compound was found to be more effective than the anhydrous SnO2 both as a flame retardant and a smoke suppressant. At a 2% incorporation level β‐stannic acid gave polymers with LOIs of up to ca 30 and reductions in smoke density of 50% or more compared with the standard non‐halogenated resin. The mode of action of the tin compounds appears to involve both the condensed and vapour phases. In view of the generally accepted low toxicity of inorganic tin chemicals their possible use as fire‐retardant additives for polymer systems should merit serious consideration.