bluuebunny/crossref_metadata_2025_split huggingface dataset:
Qualitätssicherung im Anlagenbau
Authors: Schmal Wolfgang 
Published: December 2004

AbstractQuality Assurance in Plant Construction. In recent years plant construction companies have been seeking certification on the basis of the ISO 9000 series of international standards, above all because of the international nature of their business. The present article considers the principal demands made on plant constructors, with special emphasis on customer demands. These concern, among other things, the delivery of the right plant for the given task and the reliability and flexibility of the plant constructor. The main focus is on the establishment of a relationship of trust, project definition, knowledge base, project management, risk considerations and acceptance, data processing, and the development of quality consciousness. The goals of quality production, i.e. adherence to agreed technical criteria, are taken for granted and therefore not discussed in this context.
Phasengleichgewichtsmodelle zur Synthese und Auslegung von Trennprozessen
Authors: Gmehling Jürgen 
Published: December 2004

AbstractPhase Equilibrium Models in the Synthesis and Design of Separation Processes. While approximately 20 years ago the design of separation processes required expensive and time consuming experiments, modern thermodynamic models nowadays allow a reliable prediction of the phase equilibrium behavior of multicomponent systems using binary data alone. If binary data are not available, group contribution methods can be applied to predict the real behavior. These methods have been developed for the prediction of vapor‐liquid equilibria. The range of application and the reliability of these models were improved by modification of the model, definition of new main groups and introduction of temperature dependent parameters. Especially promising models arise on utilising gE‐mixing rules in cubic equations of state. These models can be applied for the calculation and prediction of phase equilibria of strongly polar systems, including supercritical compounds. At the same time these models allow the calculation of densities, thermodynamic properties, etc.
Kontinuierliche Thermodynamik – ein Weg zur Behandlung komplexer Vielstoffsysteme
Authors: Kehlen Horst , Browarzik Dieter 
Published: December 2004

AbstractContinuous Thermodynamics – An Approach to the Treatment of Multicomponent Mixtures. In the chemical industry, complex multicomponent mixtures such as petroleum fractions or polymer systems are of great importance. Characterization experiments on such mixtures mostly result only in continuous distribution functions. In contrast, equations of chemical thermodynamics include the mole fractions of the individual components. An approach suitable for overcoming these difficulties is provided by continous thermodynamics, which is based directly on continuous distribution functions. Here, applications relating preferentially to vapor‐liquid equilibrium involved in the calculation of distillation columns are discussed. Continuous thermodynamics is seen to provide distinct advantages over the traditional approach, i.e. the pseudo‐component method.
Zur Fließfähigkeit von Schüttgütern – Definition und Meßverfahren
Authors: Schulze Dietmar 
Published: December 2004

AbstractFlowability of Bulk Solids – Definition and Measuring Principles. The flowability of bulk solids has to be known for many practical applications. The present paper describes how the flowability is defined and on which physical properties it depends. Experimental determination of the flowability using a shear test is demonstrated. Conditions influencing measuremed results are described. Finally an overview of various methods used for characterization of the flowability of bulk solids is given.
Katalytische Oxidation von Isomaltulose
Authors: Kunz Markwart , Puke Hanjo , Recker Carla 
Published: December 2004

AbstractCatalytic Oxidation of Isomaltulose. In carbohydrate chemistry the noble metal catalyzed oxidation is known as a “clean” reaction with high selectivity. Applied to the disaccharide ketose isomaltulose, the reaction gives two monooxidized and one dioxidized products contrary to the selectivity rules, which were earned for monosaccharides byHeynsin fundamental investigations. However, the kinetic studies of this reaction show that the dioxidation is a two step reaction in which the second step is inhibited by high isomaltulose concentrations. This could be used for the development of a process of technical interest for preparing the monooxidized products because the continous removal of the ionic reaction products with an electrodialysis allowed the realization of optimal reaction conditions.Kleinet al. show that these monooxidized products are important intermediates for semisynthetic polymers.
Grundlagen für die rechnergestützte Aufstellungsplanung
Authors: Erdwiens Martina , Nipper Norbert , Köster Dirk , Schmidt‐Traub Henner 
Published: December 2004

AbstractPrinciples of Computer‐Aided Assembly Planning. The assembly planning for a chemical engineering plant defines the position of the individual machines and articles of equipment in an appropriate grid (Fig. 1). Apart from the demands of pipe routing, numerous widely differing, partly contradictory, boundary conditions influence the assembly of a plant. These include, among other factors, investment and assembly costs, ease of maintenance and operation, as well as safety and environmental protection. Thus numerous specialist areas are involved in this planning work, with the definition of the „optimum”︁ solution being based on individual studies and particularly on experience.
Konversion der Chlorchemie? Eine Wertung der Prognos‐Studie aus Sicht der chemischen Industrie
Authors: Nader Franz W. 
Published: December 2004

AbstractConversion of Chlorine Chemistry? Chlorine chemistry is one of the main pillars of the German chemical industry. Conversion of chlorine chemistry should only be considered in cases of urgent ecological or toxicological necessity. However, there are no such reasons. In the Prognos Study, both the assessment of the ecological effects and the economic considerations are based on inadmissible approaches and on incomplete or erroneous, partly outdated literature data.
Zur diskontinuierlichen Rektifikation azeotroper Gemische mit Hilfsstoffeinsatz
Authors: Köhler Jürgen , Haverkamp Hans , Schadler Norbert 
Published: December 2004

AbstractDiscontinuous Rectification of Azeotropic Mixtures with Use of Auxiliary Substances. Batchwise rectification is one of the most commonly used thermal separation operation in the production of fine chemicals and pharmaceiticals, where small amounts of mixtures containing several product or auxiliary components are generally separated. Greater plant flexibility with regard to mixture composition, throughput, and separation specification often also favours batchwise over continuous processing. This publication discusses process engineering possibilities of batchwise rectification of azeotropic mixtures with the aid of various examples. It gives a detailed presentation of two industrial batch rectifications with additional feed of auxiliary substances, viz. azeotropic rectification with entrainment agent and extractive rectification. In both cases the set goal is to minimise charge times and to maximise the quantities processed in plant operation, with time‐optimised control of auxiliary substance throughput being of critical importance in both cases.
Biofouling und Biokorrosion — die Folgen unerwünschter Biofilme
Authors: Flemming Hans‐Curt 
Published: December 2004

AbstractMicrobial layers on interfaces, called “biofilms” are characterized by a polymeric, highly hydrated gel matrix of microbial origin in which the organisms are embedded and immobilized. Biofilms exhibit degradation behaviour different from that free cells and accumulate water, metabolites, and sorbe substances at the interface. They can greatly interfere with technical processes by increasing the fluid friction factor, the hydrodynamic resistance of filter membranes and heat transfer resistance in heat exchanger systems. They can cover surfaces, impart unwanted colour, and contaminate water. Biofilms can attack their support and lead to microbially influenced corrosion (MIC). It is estimated that about 20% to all corrosion damage to metals and building materials is due to microbial influence. Thus, the annual costs of biodeterioration range in billions of dollars. Biofilms play a key role in these processes. They consist of a gel matrix, formed by slime substances, in which the cells are immobilized on the surface of the material. Corrosion is an interfacial process, governed by pH, redox potential, oxygen concentration and other parameters. Biofilms, acting as a transport barrier, may change all these parameters exactly at the site where corrosion takes place compared to the water or air phase surrounding. Thus, a thorough knowledge of the properties and development of biofilms is crucial for the design of effective countermeasures.
Aerosolbildung durch spontane Phasenübergänge bei Absorptions‐ und Kondensationsprozessen
Authors: Schaber Karlheinz 
Published: December 2004

AbstractFormation of aerosols by spontaneous condensation or desublimation in condensers or absorbers often causes serious problems in industrial processes. The fine aerosol particles, formed under special operating conditions, remain suspended in gases and are carried over into downstream stages or lead to high pollutant concentrations in the exhaust gas. The present paper describe under what conditions aerosols are formed. The characteristic behaviour of aerosols is discussed with the aid of experiments and computer simulation.
Konzepte und Technologien für Mehrproduktanlagen
Authors: Fürer Stefan , Rauch Joachim , Sanden Franz Josef 
Published: December 2004

AbstractMulti‐product plants are very flexible units which are finding increasing use in the chemical industry, e. g. for the production of fine chemicals, pharmaceutical active compounds and automotive paints. Various concepts have become established for multi‐product plants, depending on the area of use and existing conditions. Technical equipment fitting in with these plant concepts is characterized by standardization, multi‐product suitability and a particularly broad area of use. The paper describes four multi‐product plant concepts and suggests criteria for selecting the suitable concept for a particular case.
Praxisbezogenes Vorgehen bei der Auslegung von Sicherheitsventilen und deren Abblaseleitungen für die Durchströmung mit Gas/Dampf‐Flüssigkeitsgemischen – Teil 1
Authors: Schmidt Jürgen , Westphal Frank 
Published: December 2004

AbstractThe design of an integral safety valve‐ blow‐off pipe system embraces the following essential steps: 1. An incident scenario must first be defined. All reasonable deviations from proper operation of plant must be considered. 2. The flow state at the entry to the safety valve must then be ascertained (one‐phase or binary flow); and 3. the minimal mass flow from the plant component to be protected must be calculated. Independently thereof, it is necessary 4. to determine the mass flow density in the blow‐off pipe system; it is usually related to the cross‐sectional area of the valve seat. The ratio of the two quantities gives the minimum necessary blow‐off cross‐sectional area. 5. In the final step, the pressure drop in the feed line and the counter‐pressure at the valve exit must be examined in order to assure reliable functioning of the valve also in conjunction with the pipe system. Steps 1. to 3. are considered in this article, and steps 4. and 5. will be addressed in Part 2 to be published in this journal. Appropriate recommendations and the necessary equations are given for each step. The main emphasis is placed on applicability of the calculations.
Netzwerktheorie verfahrenstechnischer Prozesse
Authors: Gilles Ernst Dieter 
Published: December 2004

AbstractThe concept of a network theory proposed in this paper provides a basis for systematically addressing questions concerning the design and operation of integrated processes. The route to a problem solution is characterised by the following steps. Modular process structuring takes place on hierarchically ordered levels by switching of components and linkage elements. The process module are switched mass‐ and energy‐wise by means of opposing potential and current vectors. The linkage which is switched one‐sidedly and is hence reaction‐free is a special case. Process modelling utilises modular process structuring and assigns the structural modules to behaviour‐describing modules. Process analysis examiones structural properties (stability, controllability, observability, sensitivity) and nonliner phenomena (ignition and extinction; boundary cycles; waves; chaos) of the overall process behaviour. Process design considers the layout and control of processes from holistic vantage points and aims at optimum determination of the nature, number, and switching of all the components and linkage elements of an integrated process in the light of a given production goal.
Elektrostatisches Zerstäuben von Flüssigkeiten
Authors: Wiggers Helmut , Walzel Peter 
Published: December 2004

AbstractThe electrostatic spraying of liquids is based on electrostatic forces that result from an electrical field and are capable to overcome the capillary forces. In contrast to gravitational and centrifugal fields the value as well as the direction of electrostatic fields depend not only on the setup geometry but additionally on the shape of the liquid surface. This results in a complex interaction between geometries, material properties, and mass and charge currents with respect to the formation of droplets. A capillary tip facing a wide flat counterelectrode has to be considered as the basic geometry. The electrical field needed for droplet production is maintained by a high voltage supply. One has to distinguish between droplet production solely by charge induction and droplet formation influenced by a corona discharge together with an electric wind. Characteristic time constants serve to differentiate between the different spraying modes.
Feststoff‐Fermentation – Ein historischer Überblick
Authors: Vollbrecht Dietmar 
Published: December 2004

AbstractUnder the influence of Buddhism, the oriental peoples for thousands of years took pride in an art of food preparation in which molding is an integral part by introducing boiled or roasted meat notes using solid state fermentation (SSF). SSF was brought to the U.S. in 1914 by Takamine. However, with the advent of submerged fermentation (STF), SSF became almost completely neglected in the Western world. After the World War II, SSF in automatic facilities developed rapidly in Far Eastern countries to attain a present annual market volume of about eight billion dollars. The comparative ease of running SSF bioreactors and particularly their low processing costs and considerably higher yields in comparison with STF suggest that this technology might have considerable economic importance in producing food and pharmaceutically valuable substances.
Übertragbarkeit der in chemischen Anlagen üblichen Sicherheitsbetrachtung auf biotechnische Anlagen
Authors: Lafrenz Bettina 
Published: December 2004

AbstractThe German technical regulation covering safety engineering of hazardous substances (TRGS 300) describes an approach to the consideration of safety in plant handling hazardous substances. No comparable regulation has so far been adopted for biotechnological plant. This article examines the extent to which the fundamental concepts of TRGS 300 might be applicable to biotechnological installations. To this end, the properties of the substances (biological agents and hazardous substances) and the various components of the two kinds of plant are examined. An initial partial transfer of the safety engineering principles and the associated safety requirements of TRGS 300 to biotechnological plant is undertaken. This rather coarse approach does not reveal any reasons why a modified version of TRGS 300 should not be applicable to biotechnological installations.
Prozesse der Reaktivdestillation
Authors: Stichlmair J. , Frey Th. 
Published: December 2004

AbstractReactive Distillation Processes Reactive distillation, i.e. the simultaneous implementation of reaction and distillation in a counter–current column, is a promising alternative to the conventional sequential processes. In a preceding paper the effective phase equilibrium of a reactive distillation was studied with a special focus on the determination of so–called reactive azeotropes. In this contribution, a knowledge of these thermodynamic fundamentals is applied to the conceptual design of reactive distillation processes. Furthermore, some process examples of technically important processes are presented.
Innovation und Umweltschutz
Authors: Vahrenholt Fritz 
Published: December 2004

AbstractPower supply companies and multinational companies have long been accustomed to dealing with scenarios extending as far into the future as the year 2050 – such as the contribution of energy from renewable resources to global energy supplies. In contrast, such concern with the future is painfully lacking in the political arena. It is well worthwhile considering the past when examining the future interplay between innovation and environmental protection. This historical approach demonstrates that environmental protection and technological progress are inextricably intertwined. Solving environmental problems without technology by asceticism and abstention is a rather make‐believe approach. Those who call for cars to stay in the garage usually mean other people's cars, and those who demand rationing of air travel usually mean other people's flights.
Product Engineering am Beispiel extrudierter Instantpulver
Authors: Schuchmann Heike P. , Danner Thomas 
Published: December 2004

AbstractProduct Engineering in the Case of Extruded Instant Powders.Starch based instant powders are usually produced by cooking/gelatinizing in an excess of water with subsequent drying and milling. Important product attributes are the specific weight and the instant properties of the powder, as well as the taste, the viscosity, and the mouth‐feel of the reconstituted gel. Cooking extrusion is an alternative energy saving process. Process development usually takes a long time and proves expensive due to the large number of different process parameters and their possible combinations. For two exemplary products it is demonstrated how the screw configuration and the target range of process parameters can be defined by statistical trial design. Final optimization („fine tuning”︁) and scale‐up assure efficient process design according to product needs.
Magnetisch stabilisierte Wirbelschichten – Untersuchungen zur Hydrodynamik
Authors: Böhm Dirk , Pittermann Birgit , Voß Harald 
Published: December 2004

AbstractZum Andenken an Professor HARALD Voß. Sein Enthusiasmus, seine Kreativität und seine Unterstützung wird seinen Kollegen und Studenten fehlen und stets in Erinnerung bleiben.
Von der Prozeßsimulation zur Lebenszyklusmodellierung
Authors: Marquardt Wolfgang 
Published: December 2004

AbstractFrom Process Simulation to Lifecycle Modeling Process simulation is an established technology to support the design and operation of chemical processes. Since this technology has reached a mature state, an obvious question concerns emerging technologies which may succeed process simulation in the future. This contribution attempts to answer this question. The increasing capabilities of mathematical modeling and simulation on various levels of detail increasingly ask for the integration of available but independently developed and applied technologies across the process design lifecycle. Novel computer‐based design support environments are required for this purpose. Such environments need to integrate existing modeling and simulation tools in a workflow oriented manner in order to provide context specific support during the whole design process.
Growth and characterization of LiCaGaF6
Authors: Sani E. , Rabe M. , Reck G. , Becker P. , Roßberg M. , Bertram R. , Klimm D. 
Published: December 2004

AbstractOptically clear LiCaGaF6 (LiCGaF) single crystals up to 15 mm length were grown by the Czochralski method from CaF2 deficient melts. The substance melts incongruently at 751 °C. No significant deviations of the crystal composition from the nominal stoichiometry Li:Ca:Ga=1:1:1 could be found. X‐ray structure analysis revealed that the substance crystallizes in the colquiriite type structure. LiCaGaF6 is transparent for optical wavelengths >140 – 150 nm. The thermal expansion of the trigonal crystals is α11 = α22 = 18.7×10‐6 K‐1 perpendicular [001] and α33 = 2.7×10‐6 K‐1 parallel [001]. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The crystal structure of high‐temperature α‐CsB5O8 modification at 20, 300, and 500°C
Authors: Filatov S. , Bubnova R. , Shepelev Yu. , Anderson J. , Smolin Yu. 
Published: December 2004

AbstractThe crystal structure of the α‐CsB5O8 high‐temperature modification has been refined by single crystal X‐Ray diffraction at 20, 300, and 500 °C. The structure is based on the zigzag boron‐oxygen layers built up from rigid <2Δ□>‐<2Δ□> pentaborate groups. Cs atoms are located in large cavities of the layer and have nine neighboring oxygen atoms. Five oxygen neighbors are placed within the same layer as the Cs cation; the other four ones belong to two adjacent layers. Thermal stability of the boron‐oxygen triangles, tetrahedra, and pentaborate groups was established. Thermal expansion of the structure observed with the use of high‐temperature powder X‐ray diffraction has sharply anisotropic character: α11 = 27, α22 = 61, α33 = ‐8×10‐6 K‐1. The CsO9 cation polyhedron plays dominating role in bulk thermal expansion of the structure, whereas the high anisotropy is caused by partial straightening of the zig‐zag layer through hinge mechanism. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Anomalous creep behaviour of aluminium high current joint materials
Authors: Oertel C.‐G. , Tamm R. , Skrotzki W. , Brokmeier H.‐G. 
Published: December 2004

AbstractDuring creep deformation the technical aluminium alloys EN AW‐1350 (Al99.5) and EN AW‐6060 (AlMgSi0.5) under certain conditions of stress and temperature show deformation thrusts of several millimetres, indicating discontinuous dynamic recrystallization. To study this anomalous creep behaviour in more detail the alloys were characterized by global and local texture measurements using neutron and electron backscatter diffraction (EBSD), respectively. In the case of AlMgSi0.5 the main global texture component of the undeformed sample is the cube component. During deformation and dynamic recrystallization a Goss component develops. The grain size slightly decreases with dynamic recrystallization. The normal creep behaviour is characterized by a Norton exponent of 3.8 and an activation energy of 0.5 eV. These parameters indicate that the strain rate controlling process is dislocation creep. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)