bluuebunny/crossref_metadata_2025_split huggingface dataset:
Gezielte Nutzung biologischer Systeme
Authors: Marquardt Rüdiger , Präve Paul , Winnacker Ernst Ludwig 
Published: December 2004

AbstractDirected exploitation of biological systems. During the past few decades, our knowledge of molecular process responsible for genetics has increased dramatically. Discovery of the giant molecule deoxyribonucleic acid – abbreviated as DNA – as the carrier of genetic information heralded in a development which nowadays permits us to effect directed changes in the genetic material of an organism. Thus we can provide easily cultured microorganisms with genes which were previously located in a completely different genetic environment. This helps us to obtain high yields of proteins or other substances which were formerly very difficult to obtain. Higher organisms such as animals and plants can also undergo modification of their genetic equipment. This adds a new dimension to the breeding of such species. Above all, genetic engineering provides new insights into the enormously complex interplay of molecules which go to make up a living cell. The resulting understanding of life processes on a molecular level permits recognition of malfunction and therapy of the ensuring disease by new drugs. In addition to these positive aspects, genetic engineering provides scope for conducting experiments whose ethical implications demand very earnest consideration.
Simulation und Optimierung der Mehrstoff‐Rektifikation
Authors: Górak Andrzej , Krastawski Andrzej , Vogelpohl Alfons 
Published: December 2004

AbstractSimulation and optimization of multicomponent distillation. Different methods for simulating multicomponent distillation columns are presented and compared with respect to the effort required and the accuracy that may be obtained. Inclusion of mass transfer kinetics based on the laws of multicomponent diffusion in the models significantly increases computer time, but the additional accuracy in the prediction of concentration profiles may justify this effort also in design practice. In particular, the unusual behaviour of concentration profiles due to multidiffusion effects can only be explained by such improved models. The new methods of multicriteria optimization offer substantial advantages over a scalar‐optimization and, in addition to economic criteria, also allow inclusion of aspects of operational safety and of environmental requirements.
Von der Datenverarbeitung zur Wissensverarbeitung?
Authors: Henrichs Norbert 
Published: December 2004

AbstractFrom data processing to the processing of knowledge. The present article first examines the problems and the claims of artificial intelligence (AI) research. A brief survey of the principal areas of pure and applied AI research then leads to the structure and the basic functions of so‐called expert systems. The account closes with a number of critical, yet unsolved questions.
Simulationstechnik
Authors: Zeitz Michael 
Published: December 2004

AbstractComputer simulation. Modern simulation tools such as simulation languages, simulation systems, simulation environments, and expert systems support the user in solving complex simulation problems. Partial problems to be solved are the mathematical modelling of the system under consideration, the selection and application of numerical methods, the programming of the simulation problem, and the execution of simulator experiments. In this survey various methods are reviewed for the simulation of continuous dynamic systems as far as this is essential for an evaluation of available or new simulation programms. Moreover, conceptions of knowledge‐based simulation environments and intelligent simulators are discussed.
Auswirkungen moderner Prozeßleittechnik auf Sensorsysteme
Authors: Nicklaus Eberhard 
Published: December 2004

AbstractEffects of modern process control technology on sensor systems. Sensor and actuator systems constitute the interface between material and energy flow of a process and the corresponding flow of information. Sensor systems can be classified independently of one another from the viewpoint of information utilization and that of information acquisition. This article presents a general structure for sensors, which differ widely depending upon function and design. Processing of the information which becomes available leads to certain demands but also to possibilities which are largely fulfilled or exploited with the aid of inbuilt computers. This concept of sensor systems with computers and its implications for systems components are examined.
Lichtwellenleitertechnik – Trends in der Entwicklung und Anwendung
Authors: Herbrechtsmeier Peter 
Published: December 2004

AbstractFibre optics technology – Trends on development and applications. Fibre optics technology has developed rapidly after its successful introduction into commercial use. This progress has led to structural changes in the field of information transmission. New fast‐growing areas of research, development, and production have resulted. After an introduction into fibre optics technology, the most important types of fibres, i.e. silica fibres, non‐oxide fibres, and polymer fibres, are reviewed. Their various uses, production, and development trends are discussed in relation to the properties of these materials.
Ethanol‐Herstellung mit Bakterien
Authors: Sahm Hermann , Bringer‐Meyer Stephanie 
Published: December 2004

AbstractEthanol production with bacteria. Strains of Saccharomyces cerevisiae have mostly been used for the production of ethanol from sugar by yeasts. Recently it was shown that the bacterium Zymomonas mobilis has some advantages compared to yeast for the production of industrial alcohol. Compared to traditional yeast fermentation, ethanol yield is about 5% higher than with yeast, since less sugar is incorporated into cell material by this bacterium. Like yeast, Zymomonas mobilis has remarkably high ethanol tolerance which enables the bacterium to produce ethanol concentrations of more than 13 vol.‐% from sugar solutions of appropriate concentration. Investigations of the spectrum of lipids present have shown that this bacterium contains large quantities of hopanoids which are presumably of significance for the stabilization of cell membranes in the presence of ethanol. Since the cost of the sugar greatly influences the profitability fraction formed in the production of glucose syrup from wheat flour was investigated. It was shown that after enzymatic saccharification of this waste starch the glucose was efficiently fermented to ethanol by Zymomonas mobilis. It is planned to broaden the substrate spectrum of Zymomonas mobilis by gene cloning techniques so that in future pentoses, e. g. xylose or arabinose, can also be fermented to ethanol by this organism.
Modellgestützte Prozeßleittechnik in der verfahrenstechnischen Produktion
Authors: Gilles Ernst Dieter 
Published: December 2004

AbstractModel‐based process control engineering in chemical engineering production. Modern process control engineering nowadays provides almost ideal tools for the implementation of even highly sophisticated control concepts. The very reluctant acceptance of these tools is due to the following bottlenecks:

– insufficient understanding of chemical engineering control processes;
– limitations in the acquisition of sensorial primary information;
– insufficient performance of control engineering concepts.
The present articles considers how these bottlenecks can be overcome.
Kompaktiergranulieren mit Walzenpressen
Authors: Zisselmar Raimund 
Published: December 2004

AbstractCompacting granulation in roller presses. The application and handling, as well as storage and transport, of a bulk solid depend not only on its material properties but to a considerable degree upon its properties of state, such as the fineness of a solid. In cases where the excessively fine division of a solid has detrimental effects, recourse can be taken to increasing the particle size. Among the methods of granulation developed for this purpose in recent years, that of compacting granulation has prooved to be especially well suited. The heart of a compacting granulation system is the compacting process performed by roller presses. This review therefore critically examines the parameters influencing product quality, throughput, and energy consumption. Typical applications are presented to illustrate compacting granulation systems.
Selektives Trocknen gemischhaltiger Produkte
Authors: Schlünder Ernst‐Ulrich 
Published: December 2004

AbstractSelective drying of mixture‐containing products. Properties and quality of products containing solvent mixtures can be influenced considerably by the drying process. This concerns, e. g. the aroma content of fruit concentrates, the tear resistance of paper, the intensity of the colour of pigments, the ductility of cable insulation, toxic residues in tablets, residual monomers in polymers, etc. Both, the amount of residual moisture and its composition are of decisive importance. Predictions are possible given a knowledge of both the course of the drying curve and the course of the composition curve. The latter results from five basic physical processes, viz. vapour‐liquid‐solid phase equilibria, diffusion in the gas phase, diffusion in the liquid phase, capillary flow, and heat transfer. This combined action can be described both theoretically and experimentally for simple but indicative cases. There result practical hints for the choice of dryers and drying conditions to fulfill the demands placed on the properties of the dried product.
Entwicklungstrends von Sensoren in der chemischen Technik
Authors: Gundelach Volkmar G. 
Published: December 2004

AbstractTrends in the development of sensors in chemical engineering. The present article surveys the state of the art and future developments of sensors, mainly in the chemical industry. Existing requirements are compared with solutions becoming possible by means of present or developing new technologies and measuring concepts. The discussion covers a wide range, from sensors for classical state variables to sensors for the determination of concentrations and biotechnological variables. It includes data communication and modern process control. Among new technologies microelectronics and integrated microcomputers are rated highest; in addition possible uses of electrooptics and glass fiber techniques are mentioned as well as solid state and biochemical components. Within the new concepts, measurements based on modelling and multisensor systems have gained a firm position in practical applications.
Rheologische Stoffeigenschaften – Erklärung, Messung, Erfassung und Bedeutung
Authors: Henzler Hans‐Jürgen 
Published: December 2004

AbstractRheological properties – Explanation, measurement, determination, and significance. The non‐Newtonian viscous (structurally viscous, dilatant, plastic, thioxotropic, rheopexic) and elastic properties of liquids are explained with the aid of examples and the main methods of measurement are described. In the case of elastic behaviour, particular attention is given to similarity of measurements obtained by different methods (normal stress measurements, relaxation experiments, vibrational measurements). The second part of the paper is concerned with analytical determination of rheological properties via special material functions, their dimensionless formulation, and their consideration in the dimensional analysis of physical processes. The significance of non‐Newtonian properties in the description of physical processes is demonstrated by an example.
Einsatz von fossilen Brennstoffen zur Energie‐ und Wärmeerzeugung
Authors: Bitterlich Eberhard , Adrian Fritz 
Published: December 2004

AbstractUse of fossil fuels for generation of energy and heat. The 1985 primary energy demand of the Federal Republic of Germany of 385 million tons of coal equivalent was met to the extent of about 90% by fossil fuels; one third of the primary energy consumption ist lost on conversion of primary into secondary energy. Since the market for energy and heat together accounts for about 70% of end user energy, this is where the greatest potential lies for saving non‐renewable resources. High‐temperature processes for energy generation have considerable development potential due to using combined gas‐steam turbine processes and to raising the upper cycle temperature. In the case of coal fired power stations this requires the inclusion of coal gasification plant. For low temperature processes, utilization of waste heat from power plant and industrial processes not only leads to conservation of fossil fuel reserves but also protects the environment from the illeffects of waste heat. The state of the art and future prospects are presented.
Wärmetransformatoren für die Chemische Industrie aus der Sicht des Anwenders
Authors: Plöcker Ulf , PreußNer Uwe , Brandt Bernd 
Published: December 2004

AbstractAbsorption heat transformers for the chemical industry as seen from a user's point of view. Absorption heat transformers can transfer waste heat, that could not hitherto be reused, to a higher temperature level. This is of special interest for the chemical industry, where there is both waste heat available at temperatures below 100°C and a demand for heat at 120 to 150°C. Though absorption heat transformers are able to recycle only a part of the total waste heat, they only need a negligible amount of additional, expensive exergy. The present status of development and advantages and disadvantages of the concept are discussed from a user's point of view. In view of the present low price of energy, special attention is given to economic considerations.
Auslegungskriterien für die Extraktion mit chemischer Reaktion und Flüssigmembran‐Permeation
Authors: Bart Hans‐Jörg , Bauer Andreas , Lorbach Dirk , Marr Rolf 
Published: December 2004

AbstractDesign criteria for extraction with chemical reaction and liquid membrane permeation. Design criteria for extraction and liquid membrane permeation are discussed and related to these classical extraction columns. Well known models, like the diffusion and the forward mixing model, are used to describe the concentration profile in a column. Mass transfer models for a single globule, like the two‐layer and the shrinking core model, are incorporated. The complex chemical interactions on an interface are formulated. A final discussion considers the relevance of the model parameters and their influence on mass transfer.
Die Rolle der Kohle als Energie‐ und Rohstoffträger
Authors: Ziegler Alois 
Published: December 2004

AbstractRelevance of coal as a source of energy and raw material. Coal ist a versatile energy and prime material whose many benefits were widely used in engineering and the economy until the middle of the present century. Starting three decades ago, however, mineral oil, natural gas, and nuclear energy have caused a substantial restructuring of energy supplies in the Federal Republic of Germany. Based on the present economic and technological situation of coal production and conversion, the paper illustrates the steadily growing contribution coal is expected to make to worldwide energy supplies. The associated technology thus ranks among the so‐called key technologies and as such deserves to be “fostered” and improved.
Sichere Lagerung von Stoffen in der chemischen Industrie
Authors: Pilz Volker 
Published: December 2004

AbstractSafe storage of chemicals. Stored chemicals can be a health risk, combustible, unstable, or explosive. It is consequently necessary to prevent such substances and their reaction products from damaging the environment or endangering people as a result of their release, decomposition, fire, or explosion. Storage conditions must therefore always be appropriate for the properties of the substances. This paper starts by outlining the basic principles of safe storage, namely minimization of potential hazards, avoidance of potential causes of danger and containing of any possible effects. Examples illustrate how the properties of the substances are taken into account in practice.
Optimaler Energieeinsatz in der Chemischen Industrie
Authors: Körner Helmut 
Published: December 2004

AbstractOptimal use of energy in the chemical industry. Energy costs represent a considerable proportion of manufacturing costs in the chemical industry. Optimization of energy consumption is therefore an important task, but supply and removal of energy also should be considered in the field. Rising oil prices and a predictable lack of steam from power plants required a new concept of the energy supply at the Ludwigshafen site of BASF. Saving energy turned out to be the best solution, considering the oil price, the costs of investment in power plants and the risks of further developments. Some examples explain the procedure and the results of this concept. Though production has increased by 60% since 1970, the consumption of primary energy has been reduced to less than 50%. Investments in power stations have been avoided, but capital had to be spent in energy saving measures and modifications of supply structures. The processes of productions have been improved, air pollution has decreased, the environment has been relieved. Energy saving remains an important task for the future in spite of present low oil prices.
Produktionslogistik in der chemischen Industrie
Authors: Lenz Jürgen 
Published: December 2004

AbstractLogistics in the manufacture of chemical products. This survery covers the fields of location analysis, organization of operational material flow, and materials management, all of which are interlocked with each other. Logistics problems with location analysis lie in the area of infrastructure, procurement, and distribution. The organization of the operational material flow has to be based on a closed concept, taking simultanously into consideration interests of production techniques and of logistics. Special attention has to be paid to the reciprocal effect of plant and storage capacity. With complex production structures simulation models should be used, including a statistical model of the market demands, systematic variation of material flows, and grouping of technical equipment. Target is a minimization of total cost. For market oriented operation of complex productions, integrated materials management systems have to be employed. The systems supply a transparent material flow starting from the market demands via the control of production up to the procurement of raw materials.
Modellbildung für Mehrphasenströmungen in Reaktoren
Authors: Zehner Peter 
Published: December 2004

AbstractModelling multiphase flow in reactors. This paper is intended to enhance the knowledge of two phase reactors. Their performance depends not only on reaction kinetics but essentially on fluid‐dynamically fixed quantities such as volume fractions, dispersion coefficients in the fluid and in the gas phase, as well as the volumetric mass transfer coefficient. These are basically dependent on the slip velocity of the phases and on the internal circulation speed of the fluid. The circulation either results from the fluid passing through the vessel (as in a bubble column) or it has to be effected separately in order to avoid separation. Suspension of solids or aeration of liquids in loop and stirred reactors can serve as examples. Dimensionless groups that characterize the main material and geometric properties can be derived using the slip velocity of the largest stable bubble and a certain circulation parameter. The power of this method will be shown by the characterization of bubble columns and gas‐liquid mixers. Simple laws comparable with those applying to bubble columns emerge when approaching the flooding point of a disc turbine in a tank. Power numbers, gas volume fractions, and volumetric mass transfer coefficients can be bundled over the whole spectrum of the non‐flooded states, when their characteristic quantities are divided by the quantities relating to the flooding point.
Bioreaktoren — derzeitiger Stand und erkennbare Entwicklungen
Authors: Deckwer Wolf‐Dieter 
Published: December 2004

AbstractBioreactors – State of the art and recognizable future developments. Industrial biotechnological processes, which require monoseptic conditions, are currently performed largely batchwise in stirred tank reactors. A broad‐based exploitation of the potential of biotechnology, i.e. both in the production of commodity biologicals/chemicals and in the manufacture of products of the „new”︁ biotechnology, requires, for economic and technological reasons, continuous processes and other reactor configurations, which permit increased biomass concentrations by cell retention or immobilization, and integration of work‐up operations.
Die Entwicklung von Iösungsmittelselektiven Membranen und ihre Anwendung in der Gastrennung und Pervaporation
Authors: Strathmann Heiner , Bell Carl Martin , Gudernatsch Wilhelm , Kimmerle Klaus 
Published: December 2004

AbstractDevelopment of solvent‐selective membranes and their use in gas separation and pervaporation. Pervaporation and gas separation are two membrane processes whose industrial and economic importance has increased considerably in recent years because they are particularly suitable for selective removal of organic solvents from aqueous and gaseous mixtures. The problem of solvent removal is encountered, inter alia, in the purification of certain industrial gaseous and liquid effluents. However, the removal of solvents is also significant in petrochemistry and biotechnology and both pervaporation and gas separation can again be efficiently used here. On the basis of the equations relating to mass transfer in homogeneous polymers, criteria for the choice of polymers for high‐selectivity membrane production are discussed. The development of suitable membranes and membrane modules is described. Two industrially and economically relevant examples, viz. recovery of organic solvents from gaseous effluent and the continuous removal of ethanol from bioreactors, illustrate the scope and limitations of the procedures.
Bildung und Koaleszenz von Blasen und Tropfen
Authors: Blaß Eckhart 
Published: December 2004

AbstractFormation and coalescence of bubbles and droplets. Generation and coalescence of bubbles and droplets are essential requirements for technical reactions and exchange processes. The paper deals with the dispersion of gases and liquids with the aid of single orifices and of sieve plates in liquids of various viscosities under gravity and centrifugal conditions and furthermore with the mechanical foam separation and with the coalescence of drops on inclined plates. The paper summarizes results from the literature as well as from the Sonderforschungsbereich (SFB) 153 at the Technical University of Munich.
Makro‐ und Mikromischen im Rührkessel
Authors: Geisler Reinhard , Mersmann Alfons , Voit Harald 
Published: December 2004

AbstractMacro‐ and micromixing in stirred tanks.Macromixing time, based on turbulence theory, is calculated theoretically as a function of the specific power input, the kinematic viscosity, the Schmidt number, and the degree of segregation. A comparison of the micromixing time with data for macromixing found in literature reveals that the micromixing time governs the reaction for very small vessel diameters. If the vessel diameter is greater than the critical size than the turbulent macromixing time controls the mixing process. The micromixing time θmikrois calculated by means of the experimental results of the turbulent velocity distributions in different stirred vessels for several geometrical arrangements of stirred tanks and different positions of feed input. The calculated data for turbulent mixing times are only valid for geometrically optimized stirred vessels. The necessary mixing time may increase or, if a chemical reaction of 2nd order takes place, the desired yield of the product may decrease considerably if the geometrical conditions are not taken into account.