bluuebunny/crossref_metadata_2025_split huggingface dataset:
Liposomen – Strukturen und Herstellung
Authors: Nothelle Ricarda , Hamann Hans‐Jürgen 
Published: December 2004

AbstractThe general public has only recently become familiar with liposomes through their use in cosmetics although a wide range of applications has long been known in the scientific literature. Depending upon the pertinent application very different liposomes are required, which has led to a large number of methods for their production. This article describes the principal processes: rotor/stator dispersion, the injection method, dialysis, extrusion, and homogenisation. The most suitable methods for industrial use are rotor/stator emulsification, the injection method, extrusion, and homogenisation. Examination of commercially available liposome‐containing products shows that high‐value products such as cosmetics and pharmaceuticals predominate – commercial use of liposomes is often limited by the sophisticated production methods and expensive raw materials.
Auslegung von Zyklonabscheidern für Notentlastungssysteme
Authors: Schmidt Jürgen , Giesbrecht Hartmut 
Published: December 2004

AbstractThe principal dimensions of cyclone separators for emergency response systems have been optimized by determination of the gas loading capacity for geometrically similar cyclones of 290 and 1000 mm diameter. For the experiments, separators made of Plexiglas with top or bottom mounted inlet tubes, with varying feed diameters and top and exit geometries. Moreover, the properties of the liquid in the binary mixture to be removed were also changed. For scale‐up the gas volume flow density in the defiecting apron should be limited. Overall the measurements have shown that the optimized equipment is equally suited for removal of aqueous, viscous, and foaming media. The flows encountered in emergency blow‐down of reactors can therefore be reliably separated. Compared to the recommendations given in the literature, significantly smaller equipment is required for the same separation performance.
MINIPLANT‐Technik – ausgewählte Aspekte der apparativen Gestaltung
Authors: Steude Heinrich E. , Deibele Ludwig , Schröter Jürgen 
Published: December 2004

AbstractOnly in exceptional cases do literature data and computer programs suffice as a basis for the dimensioning of new engineering processes in the chemical industry. As a rule, the new process is constructed with all process steps on a laboratory scale and operated with original products. In doing this, use of made of MINIPLANT engineering, with each process step being performed on the smallest scale which will still permit reproducible operation. This eliminates the need for sophisticated pilot plant. This article presents MINIPLANT equipment for fluid processes such as distillation, rectification, evaporation, and liquid‐liquid extraction, for which miniaturisation is farthest advanced. In the development of smaller equipment for solids processing such as drying, crystallisation, and size reduction, further efforts will be required. In conclusion, problem solutions in the area of automation and control are also addressed.
Tomographische Meßverfahren – Visualisierung zweiphasiger Strömungsfelder
Authors: Reinecke Nicolas , Petritsch Georg , Schmitz Dirk , Mewes Dieter 
Published: December 2004

AbstractSome applications of electrical tomographic techniques for the measurement of gas/liquid flows in packed columns are described. Electrical tomography is nonintrusive, of high temporal resolution, low cost, engenders no radiation hazard and is easy to implement. This mainly encourages the development of capacitance, resistance and inductance sensing techniques which are applied within volumetric fields of density, pressure, concentration, temperature, velocity or void fraction. The mentioned fields are instationary most of the time or they are of transient character. Therefore, not only temporal but also spatial resolution is required. X‐ray tomography is used for the visualisation of gas‐liquid flow inside packed columns. The measurement system consists of a fixed X‐ray tube and an array of 15 detectors. The spacial resolution is of the order of 0.4 × 0.4 mm, the temporal resolution is increased by use of only 12 steps of rotation and a filtered back‐projection algorithm.
Theorie und Praxis bei Rauchgaswäschen
Authors: Ulbrich Michael , Meckl Stefan 
Published: December 2004

AbstractPractical experience acquired on operation of large scale flue gas scrubbers often fails to agree with the theoretical knowledge on which the design and operation of flue gas scrubbers are based. The absorption of SO2, HCl, and mercury reveal the additional effects to be considered for optimal design and operation of flue gas scrubbers. Mist formation, wetting of plastic packing, or the buffer effect on the absorption of concentration peaks are such additional effects. The influence of these effects on the design and operation of flue gas scrubbers is analyzed by the calculation of typical examples.
Experimentelle und theoretische Untersuchungen der Gradientenchromatographie von Proteinen
Authors: Mihlbachler Kathleen , Anspach Friedrich Birger , Seidel‐Morgenstern Andreas 
Published: December 2004

AbstractPreparative liquid column chromatography is a powerful method for the isolation of proteins from complex mixtures. The use of solvent gradients has proved invaluable in the optimisation of the chromatographic separation process. In contrast to isocratic chromatography, the eluting strength of the solvent is increased during the separation. To this end, an increasing proportion of a solvent of high eluting strength is added to solvent of low eluting strength. This publication is intended to contribute to the general understanding of and to a quantitative description of preparative gradient chromatography of dissolved proteins. The analysis is based on the experimental determination of various chromatograms of the model protein lysozyme on a cation exchanger.
Abtrennung organischer Dämpfe mit Membranen
Authors: Nitsche Volker , Ohlrogge Klaus , Stürken Kai 
Published: December 2004

AbstractRemoval of Organic Vapours by Membranes Even on consistent use of productionoriented environmental protection measures it still proves impossible to avoid the formation of solvent‐containing gaseous effluents in many production processes. Thus the reduction of emissions by purification of solventcontaining process and exhaust gas streams is still a highly topical matter. Thermal, catalytic, or biological oxidation processes leading to destruction of the organic solvents should only be used when solvent recovery is impossible. Preference should always be given to those processes which protect resources by permitting recovery of solvent. Substantial advances in the area of membrane technology during the past ten years mean that gas permeation now constitutes an interesting alternative to conventional processes. Combination of a membrane separation stage with direct or indirect condensation gives a hybrid process permitting gentle and contamination‐free recovery of organic components. This article briefly summarises the fundamentals of permeation of gas/vapour mixtures through polymer membranes.
Techniken und Anwendungen der Ultraschall‐Zerstäubung – Ein Rückblick auf 35 Jahre Forschung und Entwicklung
Authors: Lierke Ernst Günter 
Published: December 2004

AbstractTechniques and Applications of Ultrasonic Atomisation – 35 Years of Research and Development in Retrospect. In the course of the last 50 years, ultrasonic atomisation has developed from a somewhat exotic laboratory technique with few, hardly used applications to a well established one with a broad spectrum of applications. Today's optimised atomisers for process engineering applications operate at volume flows between a few ml/min and several 100 l/h and droplet diameters between 1 and about 150 micrometers. The technique can handle both „normal”︁ liquids for therapeutic inhalation, for air humidifiers, carburettors, oil burners, etc. as well as solutions and suspensions for spray drying and melts of low to high melting temperatures and viscosities. The author reports on the development of ultrasonic atomisers and not only describes the physical principles and technical features of the various atomiser types but also considers borderline topics of droplet and particle generation with vibrating nozzles and cavitation chambers.
Biologischer Abbau chlorierter Kohlenwasserstoffe
Authors: Wiesmann Udo , Herbst Brendan 
Published: December 2004

AbstractBiological Degradation of Chlorinated Hydrocarbons.Chlorinated hydrocarbons (CHC) have been produced on an industrial scale since the 1920's and 1930's and are frequently used as solvents, extractants, and disinfectants. Because their low biodegradability they are often enriched in the food chains of animals, resulting in high mortality. It is therefore necessary to prevent the discharge of CHC's into water, air, and soil. They are often not biodegraded in municipal or industrial activated sludge plants or in trickling filters. Until harmless substitutes become widely available, CHC's will continue to pose a threat and must be eliminated from all effluents before entering wastewater treatment plants. Information about specific conditions for anaerobic and aerobic biodegradation of selected CHC's is given below. Two topics will be discussed in greater detail: the kinetics of dechlorination and mineralization and some examples of the reaction engineering process in lab and pilot scale.
Actin and alpha‐actinin dynamics in the adhesion and motility of EPEC and EHEC on host cells
Authors: Shaner Nathan C. , Sanger Joseph W. , Sanger Jean M. 
Published: December 2004

AbstractTwo pathogenic Escherichia coli, Enteropathogenic E. coli (EPEC) and Enterohemorrhagic E. coli (EHEC), adhere to the outside of host cells and induce cytoskeletal rearrangements leading to the formation of membrane‐encased pedestals comprised of actin filaments and other associated proteins beneath the bacteria. The structure of the pedestals induced by the two pathogens appears similar, although those induced by EHEC are shorter in length. Fluorescence Recovery After Photobleaching (FRAP) was used to determine potential differences of actin polymerization in EPEC and EHEC induced pedestals in cultured PtK2 cells expressing either Green or Yellow Fluorescent Protein (GFP or YFP) fused to actin or alpha‐actinin. When all the fluorescent actin in a pedestal on EPEC‐infected cells was photobleached, fluorescence recovery first occurred directly beneath the bacterium in a band that grew wider at a rate of one micron/minute. Consistently observed in all EPEC‐induced pedestals, whether they were stationary, lengthening, or translocating, the rate of actin polymerization that occurred at the pedestal tip was approximately 1 μm/min. Overall, a much slower rate of actin polymerization was measured in long EHEC‐induced pedestals. In contrast to the dynamics of GFP‐actin, recovery of GFP‐alpha‐actinin fluorescence was not polarized, with the actin cross‐linking protein exchanging all the length of the EPEC/EHEC induced pedestals. Surprisingly, the depolymerization and retrograde flow of pedestal actin, as well as pedestal translocations, were inhibited reversibly by either 2,3‐butanedione monoxime (BDM) or by a combination of sodium azide and 2‐deoxy D‐glucose, leading to an increase in the lengths of the pedestals. A simple physical model was developed to describe elongation and translocation of EPEC/EHEC pedestals in terms of actin polymerization and depolymerization dynamics. Cell Motil. Cytoskeleton 60:104–120, 2005. © 2004 Wiley‐Liss, Inc.
Universality of local eigenvalue statistics for some sample covariance matrices
Authors: Ben Arous Gérard , Péché Sandrine 
Published: December 2004

AbstractWe consider random, complex sample covariance matrices$${1 \over N}$$X*X, whereXis ap×Nrandom matrix with i.i.d. entries of distribution μ. It has been conjectured that both the distribution of the distance between nearest neighbor eigenvalues in thebulkand that of the smallest eigenvalues become, in the limitN→ ∞,$${p \over N}$$→ 1, the same as that identified for a complex Gaussian distribution μ. We prove these conjectures for a certain class of probability distributions μ. © 2004 Wiley Periodicals, Inc.
Structural phase transition in Tb5(Si0.6Ge0.4)4 at low temperature
Authors: Kupsch A. , Levin A. A. , Meyer D. C. 
Published: December 2004

AbstractHerein we report on crystallographic details of a structural phase transition measured with powdered Tb5(Si0.6Ge0.4)4 at low temperatures (150 and 130 K). The pseudo‐binary compound is monoclinic at room temperature (P1121/a). Changes of reflection intensities and positions in the diffraction patterns indicate a structural phase transition between 100 K and 150 K, where the compound orders in an orthorhombic structure (Pnma). This is in accordance with a magnetic phase transition from paramagnetic to ferromagnetic state (TC = 150 K), where the compound exhibits the giant magnetocaloric effect. Split‐up crystallographic sites of the monoclinic unit cell degenerate to sites of higher symmetry in the orthorhombic structure. Changes in the corresponding bond lengths are listed in detail. It turned out that both phases coexist at the selected temperatures but the phase content changes significantly. The observed phase transition is very similar to that reported for Gd5Si2Ge2, that is a shear movement of pairs of nearly rigid slabs of atoms along a direction by 0.84 Å and the tremendous increase of selected (Si/Ge)‐(Si/Ge) distances from 2.64 to 3.59 Å in between those slabs. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
In situ high‐temperature X‐ray diffraction study of the Rb2O‐B2O3 glass forming system
Authors: Bubnova R. S. , Krzhizhanovskaya M. G. , Polyakova I. G. , Filatov S. K. 
Published: December 2004

AbstractThe results of X‐ray structural analysis, in situ powder high temperature X‐ray diffraction (HTXRD), DTA and annealing studies are summarized to refine the phase equilibria in the Rb2O‐B2O3 system in air. Samples were prepared by solid state reaction as well as by the crystallisation of glasses. Investigations show that, in the latter case, high‐temperature metastable phases crystallise first, and it takes some months to reach phase equilibria. The recent determination of crystal structures of Rb2B4O7, Rb3B7O12, Rb5B19O31, α,β‐RbB3O5 and β‐RbB5O8 along with the HTXRD and DTA study led to substantial revising of the Rb2O‐B2O3 phase diagram between the 5‐50 mol. % Rb2O compositions. New compounds Rb3B7O12 and Rb5B19O31 and new phase relations in this connection are presented. The low (α) and high temperature (β) modifications of RbB3O5 were discovered and α⟷β transition is studied in details by powder HTXRD. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The possibility of characterizing the severity of fires by a single parameter
Authors: Harmathy T. Z. 
Published: December 2004

AbstractBecause language conveys the idea of fire severity by a single expression, it has always seemed desirable to find a single variable for its quantification. The earlier suggestion by the author that the total heat absorption per unit surface area of the compartment boundaries during the period of full fire development, to be referred to as overall heat load, be used as a measure of destructive potential of fires, has been critically examined. It has been found that for many reinforced and prestressed concrete building elements, the overall heat load is indeed an approximate descriptor of the severity of compartment fires, irrespective of their temperature histories.
Smoke measurements: An assessment of correlations between laboratory and full‐scale experiments
Authors: Quintiere James G. 
Published: December 2004

AbstractAn extensive review is presented demonstrating the nature of comparison between full‐scale fire smoke data and test method results for materials. These correlations are presented in terms of consistent parameters established through a development of the governing equations for smoke concentration and light attenuation. Visibility data limited to light transmission through smoke are also presented. The complex dependence of smoke production on many parameters acting in fire growth limits the success of simple correlation methods. Recommendations are made for further research to establish a sound basis for correlations, and the prediction of smoke obscuration due to fire.
Theory of fire and fire processes
Authors: Rasbash D. J. , Drysdale D. D. 
Published: December 2004

AbstractThere are two major fire processes, an understanding of which is essential for effective fire safety design: (1) the conditions under which a combustible material may become involved in flaming combustion, and (2) the rate at which such a material, once involved, will provide an output of heat, smoke, toxic gases, etc., which can endanger people and property. The first process may be regarded as covering both ignition and spread of fire on materials; its complement is the way in which fire may become extinguished. It is necessary for such processes to bring in a characteristic of the basic combustion reaction which, directly or indirectly, expresses the reactivity of the combustion process. Thus pilot ignition is usually associated with an approximate surface fuel temperature. More basically, it is associated with a critical flow rate of volatiles and a critical heat loss from the flame, the latter being influenced by ambient oxygen and temperatures conditions as well as heat lost and gained by the fuel itself. The most important factor governing the production of dangerous product is the rate at which volatiles first (fuel controlled fires) and later air (air controlled fires) are fed into the flames. The reactivity is of less importance, although it may be one of the factors which control combustion efficiency. In general, the more efficient is the combustion the more heat is produced, but the less smoke and toxic gases are produced. Some of the main advances in the above areas are reviewed in this paper.
The behaviour of thermoset polymers under fire conditions
Authors: Nicholson John W. , Nolan Philip F. 
Published: December 2004

AbstractThis paper reviews the current literature on the behaviour of thermoset polymers under fire conditions. These polymers are important and widely used materials. They are generally infusible and insoluble, and consist, on the molecular scale, of extensive cross‐linked networks rather than discrete macromolecules. Materials in this class include phenol‐formaldehydes, epoxides, cross‐linked polyester, amino resins and polyurethanes. As the use of plastics generally has grown, so there have been changes in the conditions prevailing in modern fires, and such changes are described, together with the potential fire hazards arising from the varying uses of the individual thermosets. Subsequently, literature on the pyrolytic and combustion characteristics of these materials is reviewed in order to assess their probable behaviour in real fires. Finally, existing approaches towards improving their fire behaviour are described.
Correlation of smoke and fumes from overheated materials in an aircraft fuselage and in a laboratory test apparatus
Authors: Christopher A. J. 
Published: December 2004

AbstractTo assess the utility of a laboratory test for smoke and fume emission from overheated materials, six materials were heated to 500°C in larger amounts in three locations in an air‐conditioned aircraft fuselage on the ground. Smoke, acidic or alkaline gases and carbon monoxide were monitored. It was shown that the laboratory test results could be a basis for predicting the smoke‐ and fume‐emission behaviour of materials subjected to overheating, e. g. in aircraft in flight.
Effect of calcium carbonate filler on the fire and smoke properties of moulded polypropylene
Authors: Grayson S. J. , Smith D. A. 
Published: December 2004

Abstract‘Oxygen Index’, ‘Rate of Burning and Extent of Burning of Self‐supporting Plastics in a Horizontal Position’ and ‘Vertical Flammability’ tests were used for examination of polypropylene copolymer HW 607M and the same copolymer filled with 40% w/w calcium carbonate. Room‐scale studies were also carried out using a range of standard ignition sources. In the latter tests, measurements of the levels of smoke generated in the test chamber were monitored continuously, and intermittent measurements were made of the carbon monoxide concentrations. Small‐scale testing showed that addition of the filler to the polypropylene raised the limiting oxygen index of the polymer from 17.8 to 20.3, which is only marginally lower than the oxygen concentration in ambient air (20.9); this introduces the possibility of a filled polypropylene which is not ignitable in air. However, the results of the UL94 and ASTM D635 tests did not show significant differences in flammability and rates of vertical and horizontal flame spread as between the two materials, through the unfilled polymer produced extensive burning droplets early in both tests whilst the filled polymer did not. Such droplets can spread fires to floor coverings, so that the filled plastic might be preferable in application. In our laboratory tests, the filled samples gave considerably lower smoke generation than the unfilled ones. At high heat fluxes they generated considerably less smoke than (smaller) unfilled samples containing the same mass of polymer. This suggests that the calcium carbonate has specific smoke‐suppressant activity and is not merely acting as a polymer diluent. In larger‐scale tests, unfilled samples were readily ignited by a domestic match, whilst the filled samples required an ignition source of 43 kJ (some six times greater than the match source) in order to light them and sustain ignition. The filled polymer did not melt on ignition and there was no lateral spread of flame from the sample. Smoke generation was considerably lower, the average optical density at maximum obscuration being 0.27, compared with 0.84 for the unfilled control. In particular, smoke suppression achieved by use of calcium carbonate at higher heat‐flux levels is considerably greater than that expected for an inert diluent.
Tomorrow's safety is today's research
Authors: Watters P. 
Published: December 2004

AbstractThe paper covers the effect fire has on the individual in Society and comments on the present day hazard arising from the use of chemicals in the industrial field, transportation and storage of chemicals, impact of technological changes and the ever increasing use in the home of furnishings. In order to identify future areas of research there is a need to consider what has happened in the past and in particular to look at social and economic factors of the development of fire. Comment is made on the difficulty of identifying unknown future hazards and covers areas of development which might create special problems. The domestic scene is examined in regard to construction and content and development of design standards in buildings. Human behaviour is discussed with comment on past tragedies and their aftermath with particular relevance to the reaction of people in fire situations. The future deals with use of flammables in the home. The paper concludes by observing how the author would envisage the development of the fire service to meet the unknown challenge that lies ahead and suggests one or two thoughts on how research, and researchers, can assist in making the world a safer place to live.