bluuebunny/crossref_metadata_2025_split huggingface dataset:
Herstellung von semipermeablen Membranen und ihre Anwendung in Reversosmose‐ und Ultrafiltrations‐Anlagen
Authors: Hochscherf Ernst , Mandre Georg 
Published: December 2004

AbstractMit der zunehmenden Anwendung der Reversosmose und Ultrafiltration z. B. zur Wasserreinigung, zur Süßwassergewinnung aus Brack‐ und Meerwasser, zur Aufkonzentrierung wäßriger Lösungen usw. rücken auch die Herstellung semipermeable Membranen und ihr Einsatz in geeigneten Anlagen immer mehr in den Brennpunkt des Interesses. In diesem Beitrag wird, ausgehend von der Membran‐Struktur und dem Membran‐Bildungsprozeß, ein Überblick über die verschiedenen Membran‐Typen und ihre technisch genutzten Herstellungsverfahren gegeben. Die in der Praxis verwendeten Membran‐Trenneinheiten werden erläutert und beurteilt. Eine kritische Stellungnahme soll die Aussichten dieses Trennverfahrens aufzeigen.
Gestaltung horizontaler Rohrbündel in Gas‐Wirbelschichtreaktoren nach wärmetechnischen Gesichtspunkten
Authors: Neukirchen B. , Blenke H. 
Published: December 2004

AbstractIn Wirbelschichtreaktoren mit hoher kalorischer Leistung werden häufig Rohrbündel zur Wärmeübertragung eingebaut. Die Form verschieden angeordneter horizontaler Rohre beeinflußt die Ausnutzung des Reaktorvolumens, die Kosten der Rohre und die Wämeübertragung. Eine wirtschaftliche Bewertung von Bündeln aus runden Rohren und Flossenrohren wurde nach wärmetechnischen Gesichtspunkten vorgenommen. Hierzu waren eigene experimentelle Untersuchungen zum Wärmeübergang an Rohrbündeln notwendig. Rohranordnung und ‐teilung, Rohroberfläche und ‐form und der fluidisierte Feststoff wurden variiert. Die Auswirkungen einiger Parameter auf die vergleichende wirtschaftliche Bewertung der runden Rohre und der verschiedenen Flossenrohre werden durch beispielhafte Kostenrechnungen aufgezeigt.
Über Grenzflächenvorgänge in der Agglomerationstechnik
Authors: Schubert Helmar 
Published: December 2004

AbstractDie Grundverfahren der technischen Agglomerierung werden in Form einer systematischen Übersicht zusammengestellt und im Hinblick auf Grenzflächenvorgänge diskutiert. Nicht nur die Agglomeratherstellung, sondern auch die Eigenschaften von Agglomeraten werden von den Vorgängen an den Feststoffoberflächen entscheidend geprägt. Als Beispiel hierzu werden die physikalischen Vorgänge des Rekonstitutionsprozesses von Instantagglomeraten unter neuen Gesichtspunkten dargelegt. Mit Hilfe von vereinfachenden Annahmen gelingt es, eine für das Eindringen von Flüssigkeit optimale Agglomeratgröße abzuschätzen. Auf die Vorteile der zweistufigen Agglomeration wird hierbei hingewiesen. Die Möglichkeiten zur Herstellung von Agglomeraten, die hinsichtlich der Rekonstitution optimale Eigenschaften besitzen, werden diskutiert und die Existenz einer kritischen, möglichst nicht zu überschreitenden Porosität nachgewiesen.
Die Vorausberechnung von Dampf/Flüssigkeits‐Gleichgewichten
Authors: Onken Ulfert , Gmehling Jürgen 
Published: December 2004

AbstractZur Auslegung von Trennprozessen, die wie die Destillation und die Partialkondensation auf Dampf/Flüssigkeits‐Gleichgewichten beruhen, liegen sehr oft die erforderlichen Gleichgewichtsdaten nur unvollständig vor oder fehlen ganz. Insbesondere stehen für Stoffsysteme mit mehr als zwei Komponenten meist keine experimentellen Werte zur Verfügung. Soweit alle beteiligten Zweistoffsysteme gemessen sind, läßt sich heute das Dampf/Flüssigkeits‐Gleichgewicht der Vielstoffgemische durch Beziehungen für die Konzentrationsabhängigkeit der Aktivitätskoeffizienten beschreiben, in denen nur binäre Parameter enthalten sind. Wenn nicht für alle Zweistoffsysteme Meßwerte vorliegen, müssen die fehlenden binären Parameter vorausberechnet werden. Dazu gibt es heute Methoden, die darauf beruhen, daß flüssige Mehrstoffsysteme als Gemische von Strukturgruppen betrachtet werden. Dadurch wird die Zahl der erforderlichen binären Wechselwirkungsparameter eingeschränkt. Am weitesten fortgeschritten ist die UNIFAC‐Methode; ihre Vorhersagegenauigkeit konnte durch zusätzliche Differenzierungen in den Strukturgruppen unter Verwendung der Dortmunder Datenbank für Dampf/Flüssigkeits‐Gleichgewichte (DDB) weiter verbessert werden.
Bestimmung von Transportkenngrößen bei Mehrphasenströmungen mit Hilfe der Korrelationsmeßtechnik
Authors: Kipphan Helmut 
Published: December 2004

AbstractZur Erforschung von Mehrphasenströmungen sowie zur Auslegung, Überwachung und Regelung von verfahrenstechnischen und chemischen Apparaten ist die Messung von Transportkenngrößen notwendig. Diese Messungen sollten möglichst ohne Störung des Transportvorganges erfolgen. Es wird gezeigt, wie sich dies auf der Basis der Korrelationsmeßtechnik realisieren läßt. Hierbei erfolgt die Bestimmung von Geschwindigkeit, Massenstrom, Turbulenzgrad etc. indirekt über die Messung der stochastischen Konzentrationsschwankungen der dispergierten Phase. Den Meßverfahren liegen theoretische Strömungsmodelle zugrunde. Gerätetechnische Realisierung und automatische Anpassung an den realen Transportprozeß führen auf Meßeinrichtungen, die sich als Labor‐ und Betriebsmeßgeräte einsetzen lassen. Die Anpassung der Verfahren an unterschiedliche Mehrphasenströmungen geschieht über geeignete Meßfühler. Je nach spezieller Meßfühlergeometrie und Anordnung kann die Messung entweder lokal oder integral erfolgen, ebenso ist die Untersuchung instationärer Strömungsvorgänge möglich. Die Erprobung der Meßverfahren wird für Gas/Feststoff‐Blasenströmungen und den hydraulischen Feststofftransport beschrieben.
Festbettelektrolyse — ein Verfahren zur Reinigung metallhaltiger Abwässer
Authors: Kreysa Gerhard 
Published: December 2004

AbstractFixed‐bed electrolysis – a process for purifying waste water contaminated with metals. In an effort to combine the purification of metal‐containing electroplating wastes with the recovery of valuable materials and a recycling of the wash water greater substitution of the hydroxide precipitation will be necessary in the future. The electrochemical separation of dissolved metals represents an interesting alternative if material transport is intensified by use of a fixed‐bed electrode and the specific surface area of the electrode is so increased that high yields of recovery are achievable from low concentrations. The separation of various metals and the influence of operating parameters have been investigated on a pilot‐plant scale, and separations of down to less than one 1000th of the initial concentration and final concentrations below 0.1 ppm are currently being achieved. On the basis of these investigations an automated full‐scale plant has been developed in collaboration with an industrial firm for the treatment of copper‐containing electroplating wash waters. The first results obtained in a trial run are given.
Entwicklung und Projektierung von Anlagen zur Hochdruck‐Extraktion von Naturstoffen
Authors: Eggers Rudolf , Tschiersch Rolf 
Published: December 2004

AbstractDevelopment and planning of plant for the high‐pressure extraction of natural products. Important criteria in the designing of plant for the recovery of carrier or extract are reviewed, especially for the extraction of natural products with supercritical CO2. The quantities to be determined in the planning of a large‐scale plant are outlined and a typical process, the extraction of spices, is discussed in detail. The plant components and assemblies are presented together with their particular process engineering and construction characteristics. Finally, the thermodynamic aspects are dealt with in more detail and ways of optimizing a large‐scale plant and reducing the power consumption are outlined. Particular attention is paid to the question of optimization regarding the most economic method of operation of such a plant in the future.
Nutzen und Risiken der Chemie
Authors: Peine Hans Georg 
Published: December 2004

AbstractBenefits and risks of chemistry. The benefits of chemistry for mankind are undisputed. Without the discovery and invention of artificial fertilizers the rapidly growing population of the world could not be fed. A fourth of our foodstuffs is currently preserved and improved by crop protection. Besides, an agricultural worker now produces thirty times the amount of agricultural products than was usual fifty years ago. Many developments, such as synthetic fibers and numerous dyes have been made possible only by advances in chemistry; there was a time when dyes were worth their weight in platinum. But what are the risks which chemistry introduces? The basis of chemistry is the conversion of materials. The use of chemical products can lead to interactions with nature, and excessive or uncontrolled usage can in turn endanger life. This biological aspect is the major reason for a wide section of the population being apprehensive about the increasing use of chemical products. An isolated accident involving an explosion leads to a feeling of uncertainty among the populace. One feels that one might be involved oneself at some future date. Thus one of the chief aims in the chemical industry, compared to other branches of industry, is to ensure a very high standard of safety. But the citizen must also be kept well‐informed. There is always room for improvement in this direction, and false notions and allegations should be repeatedly corrected. Reasonable legislation which allows chemistry to play its important and positive role in the service of mankind will always be welcomed.
Die Rolle des Experiments in der Verfahrensentwicklung
Authors: Krekel Jörg , Siekmann Gerd 
Published: December 2004

AbstractExperiments in process development. Design data for the improvement of existing plants or for the development of new chemical processes are determined by experiments in laboratories or pilot plants. These frequently expensive testruns should lower the scaling‐up risk for industrial plant and should ensure its long‐term functioning and its economy. The various methods of scaling‐up and the influence of errors are discussed. Some examples will show how an exact planning of the experiments can minimize the costs of development and product.
Die Adsorptionstechnik – ein Gebiet mit Zukunft
Authors: Brauer Heinz 
Published: December 2004

AbstractAdsorption technology – an area with potential for the future. Adsorption offers considerable industrial potential for separation of individual components or mixtures of components from gases and liquids. Since the separation process occurs at ambient temperatures or only slightly raised temperatures it offers the advantage of energetically favourable conditions. Adsorption is also particularly good for isolation of components present in very low concentrations. It therefore plays a significant role in the development of trace technology. Future possibilities depend on both the development of high performance adsorbents and on the development of adsorption devices of high specific performance. Solution of physicochemical and of engineering problems are of comparable importance. The present article describes general fundamentals of adsorption, the principal properties of adsorbents, and some technical adsorption processes. Contemporary adsorber designs are presented and some developmental trends addressed.
Staubarme Pulver durch Sprühtrocknen – Erfahrungen mit neueren Techniken
Authors: Herbener Rainer 
Published: December 2004

AbstractDustless powders by spray drying – Experience with new techniques. Old drying plant with rotary‐ or nozzle‐atomizer of conventional construction produce more or less fine, dusty powder. Increasingly, there is a demand for dustless powders. A knowledge of the parameters which influence the size of the particles and the experience gained in the drying of various products was the basis for the evolution of a new spray dryer capable of producing even dustless powder. Many trials in this new spray dryer, called the FSD (Fluidized Spray Dryer) show that the powder meets all requirements. Moreover, this spray dryer will save energy and is more gently to the product by working at lower outlet temperatures.
Extraktive Stofftrennverfahren in der Biotechnologie
Authors: Hauer Edgar , Marr Rolf 
Published: December 2004

AbstractSeparation processes employing extraction in biotechnology. This publication describes separation processes involving extraction used in biotechnology, such as are being studied at the Institute for Thermal Process Engineering and Environmental Engineering at the Technical University of Graz, Austria. It is shown that research in this area is also on the increase due to the rapidly growing need for processes. Reactive extraction and liquid membrane permeation are powerful tools for the separation, concentration, and purification of polar organic compounds such as carboxylic and hydroxycarboxylic acids. High pressure extraction has the advantage that no contamination of the desired materials takes place with carbon dioxide; however, this is offset by the high price of the process. In certain cases, when only low partitioning can be achieved by conventional extraction whereas enrichment is a predominant criterion, salting out could provide an answer.
Numerische Methoden zur Simulation verfahrenstechnischer Prozesse
Authors: Dieterich Erwin , Sorescu Gheorge , Eigenberger Gerhart 
Published: December 2004

AbstractNumerical Methods for Simulation of Chemical Engineering Processes. Essential fundamentals and the current state of the art in simulating the dynamic and the steady state behaviour of chemical engineering processes are discussed. It is shown that discretization of the spatial derivatives in the balance equations leads to a system of so‐called DAE (differential algebraic equations), consisting of ordinary differential equations in time and algebraic equations. The paper discusses necessary steps to solve the DAE and mentions approved standard software for these steps as well as for the solution of the DAE as a whole.
Bei welcher Übersättigung soll man kristallisieren?
Authors: Mersmann Alfons 
Published: December 2004

AbstractAusgehend von physikalischen Modellvorstellungen wird versucht, Angaben über die optimale Übersättigung bei der Kristallisation aus Lösungen beliebiger reiner Stoffsysteme zu machen. Die Empfehlungen stützen sich auf zahlreiche experimentelle Ergebnisse, gewonnen in Kristallisatoren verschiedener Bauart und Betriebsweise für viele reine Stoffe und sind unabhängig vom Maßstab des Apparates und seinen Betriebsbedingungen.
Sicherheitstechnik am Beispiel eines erdgedeckten Tanklagers
Authors: Kupper Hans Joachim , Fürst Herbert , Ertel Bernhard 
Published: December 2004

AbstractSafety Engineering Illustrated for the Example of a Subterranean Tank Farm. The twelfth ordinance for implementation of the Federal German Immission law requires that plant according to Annex II of this ordinance must be built in compliance with the current state of the art. An overall safety engineering concept will be considered for the example of a subterranean tank farm. The technical complexity, and also the high standards of safety are demonstrated on the basis of the requirements of the pressure vessel ordinance, the water resources law, the accident ordinance, the demands of the German technical inspectorate (TÜV), company‐specific conditions, and accident scenarios. The main objective is to minimise the remaining risk, and thus to assure public acceptance, through careful construction and inspection procedures.
Anwendung von Tensiden bei der mechanischen Flüssigkeitsabtrennung
Authors: Kaiser Manfred , Burg Birgit , Köster Rita , Schreck Berthold 
Published: December 2004

AbstractUse of Surfactants for Mechanical Liquid Separation. Mechanical dewatering of finegrained solid materials can be improved by the addition of surfactants. As interface‐active substances surfactants reduce surface tension and consequently the capillary forces within the bed of solid particles. A hydrophobization of the solid surface due to the adsorption of surfactants may contribute to further reduction of moisture as well. The development of non‐foaming surfactants enables the use without distrubing other ongoing processes by the formation of foam. Investigations on the interaction between the adsorption behaviour, type of material surface, and contact time during dewatering processes support the optimization of dewatering agents. The use of surfactants is an attractive means of improving or replacing other methods of mechanical dewatering.
Grundlagen und Anwendungen – Über das schwierige Verhältnis zwischen Forschung, Entwicklung und Politik
Authors: Mittelstraß Jürgen 
Published: December 2004

AbstractFundamentals and Applications – The Difficult Relationship between Research, Development and Politics. The modern world is the product of the scientific and technical mind. Science and technology in the tradition of the schools and the workshops, respectively, came together at the beginning of this modern world, and their increasing interdependence has essentially determined its more recent developments. Technology is no longer merely applied science, and science itself moves forward in the form of technology. At the same time pure basic research, application‐oriented basic research, and product‐oriented applied research form a research continuum. Against the background of this continuum, growing demands are placed on a new kind of transdisciplinarity and on the responsibilities of science and technology for the future of a “Leonardo World”.
Anlagensicherung mit Mitteln der Prozeßleittechnik
Authors: Netter Pirmin 
Published: December 2004

AbstractPlant Securing by Means of the Process Control Engineering. The Process control engineering contributes in an important way to the environmental protection and to the plant security in the chemical industry. Due to their historical evolution and the different forms of organization the enterprises have different, but equivalent safety conceptions by process control engineering. These different procedures have been synchronized and the results have been formulated in a NAMUR recommendation. The contribution gives an information about the most important results of this work.
Elektromembranverfahren Teil 1: Grundlagen und Modellbildung
Authors: Kuppinger Franz‐Felix , Neubrand Wolfgang , Rapp Hans‐Jürgen , Eigenberger Gerhart 
Published: December 2004

AbstractElectromembrane Process – Part 1: Fundamentals and Mathematical Modelling. In electromembrane processes the cation or anion selectivity of polymeric ion exchange membranes can be used for various applications. Industrially important examples are membrane electrolysis and its reversal, the fuel cell or several electrodialytic processes with mono‐ and bipolar membranes. The electrochemical equilibrium which is responsible for membrane selectivity is discussed together with the relevant transport mechanisms within and outside the membrane. The present status and open questions of modelling electromembrane processes are considered and the efficient combination of the different phenomena into an overall model of an electrodialytic process will be addressed. Applications and a comparison of model simulations and experiments will follow as Part 2 of this survey.
Effects of infantile handling on morphological development of the rat brain: An exploratory study
Authors: Altman Joseph , Das Gopal D. , Anderson William J. 
Published: January 2005

AbstractRats were handled daily from day 2 to 11 after birth, inclusive. These animals and unhandled controls were injected on day 11 with a radioactively‐labeled precursor of deoxyribonucleic acid (DNA) and killed either 6 hr, 3 or 30 days later. In a subsequent experiment, uninjected rats were likewise permitted to survive until 11, 14, 41, or 101 days of age. Brain weight measurements were taken in all animals, and the brains from the rats of the first experiment prepared for histology and autoradiography, and evaluated quantitatively.The following differences were established: (1) The brains of the handled rats were consistently lighter than controls at 11 and 14 days; (2) These differences were not associated with differences in body weight; (3) Planimetric measurements of sampled regions showed that brain weight differences were correlated with areal size differences; (4) Autoradiographic cell counting indicated that cell proliferation and the formation of new microneurons were higher after injection in the handled than unhandled rats; (5) No differences attributable to the treatment were obtained between relative areas occupied in cortex by perikarya and neuropil. We concluded that handling leads to prolongation of brain maturation and hypothesized that it represents environmentally‐induced “infantilization.”
Electromyographic evaluation of the moro reflex in preterm, term, and small‐for‐dates newborn infants
Authors: Schulte F. J. , Linke Ilona , Michaelis R. , Nolte Renate 
Published: January 2005

AbstractThe Moro reflex motor response was studied by electromyographic analysis of extensor and flexor activity in normal fullterm, preterm, and small‐for‐dates fullterm infants. Flexor motoneuron activity increased significantly with maturation, whereas duration and amount of extensor motoneuron activity remained constant. The triceps/biceps Moro response activity quotient decreased with conceptional age. Rhythmic Moro response activity occurred in normal fullterm, small‐for‐dates, and preterm newborn infants above 34 weeks conceptional age. A special type of Moro response with delayed flexor activity was found more often in preterm than in fullterm newborn infants. The Moro response was not found suitable for an exact estimation of conceptional age. Particularly in small‐for‐dates infants, the Moro response pattern was influenced more by pathophysiological factors than by age differences.
The photic sneeze reflex in the human newborn: A preliminary report
Authors: Anderson Rebecca B. , Rosenblith Judy F. 
Published: January 2005

AbstractIn an ongoing, comprehensive study of newborn infants, visual following was tested by moving a shiny bicycle bell across the horizontal and vertical planes in front of the infant's eyes. During the course of this test, it was noted that many of the babies sneezed at the time the test object was presented. The race‐sex distribution of this sneeze response in the infant population stuided was recorded and the phenomenon discussed as an early indicator of visual sensitivity.
Programming life histories: Effects of maternal and environmental variables upon open‐field behavior
Authors: Denenberg Victor H. , Rosenberg Kenneth M. 
Published: January 2005

AbstractOpen‐field behavior was studied as a function of three classes of variables: maternal characteristics, rearing environment, and sexual experience. Mothers of experimental subjects were either handled or nonhandled in infancy. Subjects were born and reared to weaning either in maternit cages or in Hebb‐type free environments and were placed after weaning into either a laboratory cage or free enviroment. Sexual experience consisted either of bearing and raising a litter or no sexual experience. The results confirmed previous findings that offspring of mothers handled in infancy arc significantly less active in the open field than the offspring of nonhandled mothers. The maternal handling variable also interacted significantly with breeding experience: for rats which had not been bred, those raised by nonhandled mothers were more active than those raised by handled mothers; for females with breeding experience the reverse was true. Overall, thosc femalcs which had reared a litter were more active and defecated more than their nonbred littermates.