bluuebunny/crossref_metadata_2025_split huggingface dataset:
Technikfolgenabschätzung und ihre Bedeutung für die Tätigkeit des Ingenieurs
Authors: Stephan Karl 
Published: December 2004

AbstractThis special event held at the 1996 Annual Meeting of the GVC addressed the bright and the dark sides of technological forecasting. The review article on pp. 44 to 54 presents the content of a lecture delivered by Prof. Dr. ORTWIN RENN, Baden‐Württemberg Academy for Assessment of the Consequences of Technology. As an introduction to the assessment of the consequences of technology, Prof. Dr.‐Ing. KARL STEPHAN, University of Stuttgart, examined the significance of the assessment of the consequences of technology for the professional activities of the engineer. In this issue we publish extracts from his lecture.
Ingenieurkeramik in der Verfahrenstechnik — Alternativen für konventionelle Werkstoffe
Authors: Gugel Ernst , Leimer Gerhard 
Published: December 2004

AbstractThe use of ceramic materials in chemical engineering is on the increase. They have a number of advantageous properties which prove technically and economically beneficial. Realization of these benefits requires cooperation between component manufacturers and users, with due attention to appropriate design. Example of successful use are discussed.
Praxisorientierte Aufbereitung des Ermüdungsfestigkeitsnachweises für Komponenten der Druckbehälter‐ und Kraftwerkstechnik
Authors: Rudolph Jürgen , Weiss Eckart 
Published: December 2004

AbstractThe importance of the detailed analytical proof of fatigue strength of pressure vessel components is steadily growing in order to ensure safe long term operation of chemical plant and power stations. The state of the art is represented by the notch stress oriented concept of the proof of fatigue strength. It is implemented according to increasing quality requirements within pressure vessel codes and guidelines for analysis such as the German AD‐Merkblatt S 2. The main problem of its practical application is the stress analysis for fatigue including fatigue crack initiating notch stresses. Currently, only numerical instruments of analysis such as the finite elements method (FEM) allow for detailed modelling and analysis according to these needs. General results for standard pressure vessel components such as vessel‐to‐nozzle connections can be derived from parametric studies based on the finite elements method in case of swelling cyclic loading (start‐up and shutdown procedures). These results can be further processed within computer programs enabling the engineer as a user to carry out the detailed proof of fatigue strength for minimum expenditure.
20 Jahre Entwicklung einer bipolaren Membranzelle für die Alkalichlorid‐Elektrolyse vom Labor bis zur weltweiten Anwendung
Authors: Bergner Dieter 
Published: December 2004

AbstractFirst samples of perfluorinated cation exchange membranes were obtained in 1971. They were tested for use in the diaphragm process as a replacement for asbestos diaphragms. However, the special features of these membranes led to the decision to develop special new membrane electrolysis cells. A patent was sought for the first new cell design in 1975. After extensive material testing and many improvements, the HOECHST bipolar membrane cell was produced, consisting of an electrolyzer made up of individual elements, i.e. individual sealed electrolysis cells. Starting in 1982, this cell type was developed further in cooperation with UHDE GmbH. In 1983 it was installed for the first time in an industrial electrolysis plant. Despite strong competition, the bipolar HOECHST‐UHDE membrane cell has now gained an important market share. In 1998 it will be installed worldwide in 43 electrolysis plants, with a total NaOH capacity then amounting to 2.5 million mtpa.
Experimentelle und theoretische Untersuchungen zur Filtration mit überlagerter Sedimentation in Drucknutschen
Authors: Bothe Clemens , Esser Ulrich , Fechtel Thorsten 
Published: December 2004

AbstractSedimentation superimposed on industrial cake filtration leads to longer filtration times and often has a detrimental effect on subsequent process steps such as washing and demoisturing. The influence of sedimentation is seldom recognised in laboratory filtration experiments. Methods are presented for evaluation of pressure filter experiments with superimposed sedimentation which avoid the error made in the usual evaluation methods. For the case of zone sedimentation the article presents a graphical evaluation and a numerical method of modelling permitting scale up to any desired cake height. In superimposed classifying sedimentation simultaneous measurement of filtrate volume and cake height provide information about local variation in filter cake resistance. It is shown for a model system that, owing to sedimentation, the cake resistance shows a minimum at mean cake height and increases rapidly towards greater heights. The local cake resistance corelates with particle size distributions measured for layers of a horizontally cut filter cake. The method of evaluation presented permints determination of the flow resistance of the uppermost layers of a cake and hence estimation of the gas pressure necessary for demoisturing. The profiles of local filter cake resistance show that the relative cake layering is largely independent of the level of suspension filling. A scale‐up model is presented for use in those cases where classifying sedimentation cannot be suppressed.
Altanlagen – Sanierung nach TA Luft durch Kombination von Verbrennung und Absorption
Authors: Simon Eberhard , Jaenicke Ottmar 
Published: December 2004

AbstractA waste‐gas cleaning system was constructed for a group of drug production plants. The chemical – synthetic processes taking place there are characterized by inevitable emissions, mainly of vapours of organic solvents. Their concentrations vary within a wide range and at any given moment in principle remain unknown. This paper describes the initial situation and the requirements for the waste gas cleaning process, including the calculation of the gas volume flow capacity. The polluting substances were divided into two groups; for critical substances only thermal oxidation was found to be adequate, whereas for non‐critical, water‐soluble material, water‐fed absorption columns were chosen; on one hand to avoid full exhaustion of the capacity of the thermal waste‐gas system and on the other hand to offer additional possibilities in the case that this system should be out of action. The criteria for this decision as well as for the combination of one central with several decentralised cleaning units are discussed in detail. The equipment of the waste‐gas emitting plants for feeding the cleaning units and the technical details thereof are described as well as the safety design. At last, experience gaine during preparation of the systems and considerations concerning further use of the thermal cleaning system are discussed.
Das Leitbild Nachhaltigkeit und das Konzept Technikbewertung
Authors: Jischa Michael F. 
Published: December 2004

AbstractSustainable Development and Technology Assessment. Changes in the environmental consciousness of wealthy western societies began t o appear in the 1960s. These changes manifested themselves in three ways. First, in the mid‐1960s the term “Technology Assessment” (TA) was coined in the USA. The TA discussion in Germany – as well as in other comparable countries – lead t o growing TA activities and the opening of institutions connected with Technology Assessment. Secondly, in 1968, the Club of Rome was founded, which in 1972 brought out its first study “The Limits to Growth”. Thirdly, the sustainability debate followed and intensified with the report in 1980 “Global 2000” and the Brundtland report in 1987 “Our Common Future”, which formulated the concept of sustainable development. Debates intensified further in 1992 with the “Agenda 21”. the closing document of the Rio Conference for Environment and Development. The following will show both that the diffuse idea of sustainability can be operationalised with the technology assessment concept; and – as has recently taken place at the TU Clausthal – that technology assessment should be established in research and teaching at the university level.
Bestimmung der fluidelastischen Instabilität in querangeströmten Rohrbündeln
Authors: Gelbe Horst , Schröder Kai 
Published: December 2004

AbstractFor the design of tube bundle heat exchangers avoiding tube bundle damage caused by vibration, fluidelastic instability is the most important vibration excitation mechanism. In order to present a guideline in the VDI‐Wärmeatlas the existing recommendations of CHEN, WEAVER and FITZPATRICK and PETTIGREW and TAYLOR were examined. They differ in the suggested equations for calculating critical velocities for single phase crossflow. With an extensive evaluation and test of consistency of the these and newly available data on this topic, better correlations could be derived. Consistent definitions of critical flow velocity, damping, natural frequency and hydrodynamic mass are used; their values are to be determined in the still fluid with the density ρ. Confident documented data show only a small scatter. The other data deviate more, but mainly to the safe side.
Neue Materialien – Was kann die Synthesechemie heute?
Authors: Herrmann Wolfgang A. 
Published: December 2004

AbstractMaterials of construction will exert a greater influence on cultural developments on all continents than in the past, meaning that research in materials science will have to be given a high interdisciplinary priority in countries with the right scientific and technological background. Particularly in the case of this developing area, science will have to emerge from its classical compartmentalization because further progress will require joint consideration of chemical, physical, and where appropriate biological aspects, while paying due attention to the creative scope of engineering. It will become more important than ever to combine science and engineering and to derive an innovative materials architecture from the more contemplative discipline of materials science.
Analyse nichtlinearer Phänomene bei verfahrenstechnischen Prozessen
Authors: Mangold Michael , Mohl Klaus‐Dieter , Kienle Achim , Gilles Ernst Dieter 
Published: December 2004

AbstractContinuation methods combined with the concepts of stability and bifurcation theory are now widely accepted for the analysis of chemical engineering systems. Nonlinear analysis can lead to an improved process design or process operation. The integration of continuation methods into standard tools for dynamic process simulation opens a wide range of possible applications in chemical engineering. The first part of this paper gives a basic introduction into nonlinear dynamics. In the second part, that theory is applied to three different types of chemical engineering processes, which have been studied recently at the Institut für Systemdynamik und Regelungstechnik of the Universität Stuttgart.
Digitale Feldgeräte und deren Bedeutung für die Instandhaltung verfahrenstechnischer Analgen
Authors: Steinweg Andreas , Raab Helmut 
Published: December 2004

AbstractDigital Field Devices and Their Importance for Maintenance of Chemical Plant The term “digital field device” is briefly discussed in order to demonstrate the extent to which digitalization has created conditions for increased and “new” functionality in the field. The body of the article then classifies and describes this functionality according to elementary, shifted, and extended measuring functionality and maintenance functionality. The ensuing advantages and disadvantages for chemical plant maintenance are considered. The key role of communication in the field becomes very clear. An attempt is also made to present some future prospects for digital field devices.
Strömungsvisualisierung mit Texturen
Authors: Loser Thomas , Mewes Dieter , Levy Yuval , Hesselink Lambertus 
Published: December 2004

AbstractVisualisation of Flow with the Aid of Textures Many new methods of flow visualisation have been developed in recent years. One of the most promising approaches is the visualisation of flow with the aid of textures. Textures are graphic structures containing directional information. They can be calculated with the Line Integral Convolution (LIC) algorithm developed by Cabral and Leedom, according to which pixel‐oriented random entry fields are convoluted along integral lines. This paper uses the LIC algorithm for texture generation. Known procedures for texture generation and for spatial representation of textures are considered and extended by the authors' own work. Textures are compared with traditional approaches, which use flow lines and vector arrows for flow visualisation, and evaluated. In their presentation of the topic the authors use a easily comprehensible representation which the user can readily reproduce rather than an exact mathematical‐statistical analysis of texture generation.
GVC‐Fachausschuß „Prozeß‐und Anlagentechnik”︁
Authors: Bathen Dieter 
Published: December 2004

AbstractDie Sitzung des GVC‐Fachausschusses „Prozeß‐ und Anlagentechnik”︁ fand am 25. und 26. Oktober 1998 in Kleve statt. Gemeinsam mit dem DECHEMA‐Ausschuß „Computeranwendungen in der chemischen Industrie”︁ und dem GVC‐Arbeitskreis „Produktionslogistik”︁ wurden aktuelle Problemstellungen aus der Industrie und neue Problemlösungsansätze aus der Forschung präsentiert und diskutiert.In seiner kurzen Begrüßung erläuterte der Ausschußvorsitzende H. SCHMIDT‐TRAUB einerseits die Zielsetzung der Tagung und verdeutlichte andererseits den Teilnehmern die Ursachen und Konsequenzen des drastischen Rückgangs der Anfängerzahlen in den verfahrenstechnischen Studiengängen, was für Gesprächsstoff in den Pausen sorgte. Die anschließende Tagung umfaßte insgesamt 35 Vorträge in zehn Schwerpunktthemen.
Vorhersagegenauigkeit von Auslegungsmethoden für den Entlastungsquerschnitt bei durchgehender chemischer Reaktion
Authors: Friedel Lutz , Korfmann Steffen 
Published: December 2004

AbstractPredictive Accuracy of Design Methods for the Relief Cross‐Sections for Runaway Reactions On the basis of calculations performed on the results of experiments conducted in reactors with volumes up to 10 m3 for so‐called vapour‐pressure producing (runaway) reaction systems, it is found that all simplified or steadystate methods regularly afford overdimensioned relief cross‐sections. As a consequence, unnecessarily large mass flows leave the reactor to enter the containment system. A balanced design of both plants components is possible only with the aid of transient methods. In the case of gas generating reactions simplified methods also lead to excessively large pressure relief cross‐sections. Design with the aid of a transient method for such a reaction system is rendered difficult by the fact that a conservative submodel cannot be used a priori for description of the expansion behaviour. A parametric study is then required.
Listeria's right‐handed helical rocket‐tail trajectories: Mechanistic implications for force generation in actin‐based motility
Authors: Zeile William L. , Zhang Fangliang , Dickinson Richard B. , Purich Daniel L. 
Published: December 2004

AbstractListeria monocytogenes forms right‐handed helical rocket tail trajectories during actin‐based motility in cell‐free extracts, and this stereochemical feature is consistent with actoclampin's affinity‐modulated, clamped‐filament elongation model [Dickinson and Purich, 2002: Biophys J 82:605–617]. In that mechanism, right‐handed torque is generated by an end‐tracking molecular motor, each comprised of a filament barbed end and clamping protein that processively traces the right‐handed helix of its filament partner. By contrast, torque is not a predicted property of those models (e.g., elastic propulsion, elastic Brownian ratchet, tethered ratchet, and insertional polymerization models) requiring filament barbed ends to depart/detach from the motile object's surface during/after each monomer‐addition step. Helical trajectories also explain why Listeria undergoes longitudinal‐axis rotation on a length‐scale matching the helical periodicity of Listeria's rocket tails. Cell Motil. Cytoskeleton 60:121–128, 2005. © 2004 Wiley‐Liss, Inc.
Investigations of the meteoritic mineral (Fe,Ni)3P
Authors: Geist V. , Wagner G. , Nolze G. , Moretzki O. 
Published: December 2004

AbstractA survey is presented on some characteristic features of meteoritic (Fe,Ni)3P which is an abundant and important minor phase of most iron meteorites. This mineral (named schreibersite/rhabdite) plays a decisive role during the formation of the so‐called Widmanstätten pattern. Different transmission as well as scanning electron microscopic techniques have been applied to get more precise information about the real structure of the phosphide crystals, their chemical composition and the metal distribution across the phoshide/ kamacite interface. X‐ray crystal structure determinations have been performed for selected (Fe,Ni)3P ‐ cystals from various iron meteorites (Toluca, North Chile, Watson, Orange River, Morasko, Agpalilik, Odessa, Canyon Diablo). These experiments revealed a metal ordering, i.e. for the three non‐equivalent metal positions a different substitution of Fe by Ni has been found. The perfection of the brittle (Fe,Ni)3P samples differs appreciably and seems to be dependent on the thermal history of each individual meteorite. Moreover, inside Ni‐rich rhabdite crystals small monocrystalline inclusions of CrN (carlsbergite) have been detected. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Formation of diffusion‐hindering interlayers in metals in contact by dedicated thermal treatment
Authors: Meyer D. C. , Gorbunov A. , Pompe W. , Levin A. A. 
Published: December 2004

AbstractThermal evolution of the structure of Fe/Al multilayers (MLs) with nominal composition 5*(5 nm Al / 5 nm Fe) prepared by crossed‐beam pulsed laser deposition is studied by wide‐angle X‐ray scattering and X‐ray reflectometry after different temperature‐time procedures of thermal treatments under high‐vacuum conditions. In comparison to direct thermal annealing at temperatures of 250 °C and 275 °C, respectively, which results in nearly complete mixing of the MLs and formation of the FeAl intermetallic compound, quite different behaviour was found after dedicated thermal pretreatment. Annealing at successive growing temperatures before final annealing at temperatures mentioned, resulted in conservation of pronounced multilayer structure. From the results it is generalised, that also in the case of ML systems, the tendency of mixing a dedicated tuning of interface characteristics by thermal treatment allows for formation of diffusion‐hindering interlayers. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electron holographic material analysis at atomic dimensions
Authors: Lehmann M. , Lichte H. 
Published: December 2004

AbstractIn [110]‐oriented GaAs, both types of atomic columns can hardly be distinguished by conventional transmission electron microscopy (TEM) because of the small difference of atomic numbers for Ga and As with ZGa = 31 and ZAs = 33. Quantitative off‐axis electron holography allows unambiguously determining the structural polarity of GaAs in [110]‐orientation, where, besides lateral resolution, the sensitivity of the phase signal plays the most important role. In order to attribute the phase signal only to the different types of atoms, two holographic experiments were performed using the same wedge‐shaped GaAs‐crystal, where for the second experiment, the sample was inserted into the holder upside down yielding an inverse structural polarity of GaAs. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Überarbeitung der Flachsturzrichtlinie
Authors: Jäger Wolfram , Reeh Helmut 
Published: December 2004

AbstractDie Bemessung von Flachstürzen wurde bisher vornehmlich auf der Basis der vom Deutschen Ausschuß für Stahlbeton herausgegebenen Flachsturzrichtlinie in ihrer Fassung von 1979 [1] durchgeführt. Diese nimmt Bezug auf die Stahlbetonnorm in der auf dem Konzept globaler Sicherheiten beruhenden Ausgabe (s. [2]) von 1988. Mit Ende des Jahres 2004 verliert diese Norm ihre Gültigkeit, so daß eine Neuregelung der Bemessung von Flachstürzen erforderlich ist. Es wird eine kurze Information zum Stand, zum zeitlichen Ablauf sowie zur Verfügbarkeit einer ersten überarbeiteten Version der Flachsturzrichtlinie gegeben.
Flame‐Retarded polypropylene: A comparison of large‐ and small‐scale tests
Authors: Abbott C. J. 
Published: December 2004

AbstractThis paper describes work carried out on flame‐retarded polypropylene comparing results on selected small‐scale laboratory fire tests with those obtained on a larger‐scale test designed to simulate the typical real life hazard situation. In the latter test a number of important parameters such as heat build‐up, Hame spread, smoke development and gas evolution were assessed. The results indicate that there is need to use both types of tests to gain a fuller understanding prior to using new materials. An assessment based on small‐scale tests alone could be misleading and allow the use of potentially hazardous material in the particular application involved.
A fire test device suitable for small‐scale testing of fire retardant coatings
Authors: Kay M. , Price A. F. 
Published: December 2004

AbstractA fire test device suitable for small‐scale, comparative testing as a first step in investigating the performance of fire retardant materials is described. The procedure developed is not intended to predict the performance of a given material in a real fire, since the local conditions can be extremely variable. However, the parameters in the device can be varied over a wide range to screen the performance of various materials in given situation. Typical results for an intumescent mastic consisting of epoxy resin, hardener and melamine phosphate are quoted, together with appropriate calibration curves. A method of estimating the thermal resistance of the developing char is also discussed.
Studies on the measurement of smoke propensity of UPVC
Authors: Martin K. G. , Burn L. S. 
Published: December 2004

AbstractThe smoke propensity of plastics as measured in the NBS Smoke Chamber method has been rationalized in terms of the influence of specimen thickness and resolved in a relation between mass optical density (MOD) and mass loss, which gives two parameters for characterizing behaviour, a maximum MOD for thin specimens and an asymptotic MOD for thicker ones. Data have been obtained for unplasticized piolyvinylchloride formulations and compared to that obtained by the Arapahoe Smoke Chamber and the Australian Standard method (AS 1530 Part 3). Although correlation coefficients between the methods were generally poor, the same formulations were ranked as the best performers in each method and the improvement over a standard formulation was potentially important in terms of wider acceptance under Australian building regulations.