Anwendung der Unifac-Methode zur Vorausberechnung von Extraktionsparametern

Use of the UNIFAC method for the calculation of extraction parameters . In the design of an extraction process not only is a knowledge of the process engineering dependent parameters necessary but also a clear definition of the solvent to be employed and of the necessary processing data. Important quantities include the solubility behaviour of the co-existing phases and the selectivity of the solvent for the component to be extracted. As an incremental method embodying a large number of parameters, the UNIFAC method provides a means of calculating liquid/liquid phase equilibria and partition coefficients in multicomponent systems, even without a knowledge of the experimental data. In this paper the degree of accuracy of the UNIFAC calculation method is demonstrated using ternary water/n-alcohol systems as examples.     

Mechanism of water vapour gasification of carbon—A new model

The mechanism of water vapour gasification of carbon was studied by temperature-programmed desorption measurements of carbon monoxide from polyvinyl chloride cokes of different heat treatment temperatures, which were pregasified in water vapour atmospheres, and quenched before desorption in an inert atmosphere. A new mechanism of water vapour gasification of coal, coke or carbon is proposed, which assumes condention of hydroxyl groups formed by dissociation of water at active sites. The resulting ether groups which are already formed at the ‘carbon’ surface by 500°C are extremely stable (desorption of carbon monoxide in inert atmosphere above 900°C). The onset of gasification by 700°C is explained by an equilibrium shift from the ether groups prevailing at the lower temperatures to desorbable hydroxyl groups by interaction with water vapour. The subsequent steps are identical to those proposed in the generally discussed mechanism of water vapour gasification.     

Analyse der potentiellen Explosionswirkung von kurzzeitig in die Atmosphäre freigesetzten Brenngasmengen. Teil 2: Überprüfung der Modellgesetze anhand der Analyse von Schadensfällen

Analysis of the potential explosive effect of amounts of cßmbustible gases released into the atmosphere . Part 2: Testing of models on the basis of cases of damage. A theoretical model set up to estimate the strength of undampened atmospheric gas cloud explosions occurring after bursting of vessels has been secured by thorough analysis of constructional damage caused by three explosions involving vessel contents of up to 30 tonnes of hydrocarbons. The maximum peak pressure of the pressure wave at the edge of the cloud was found to be ca. 0.3 bar. Diagrams are presented which facilitate estimation of peak pressure and time of action of the deflagration pressure wave as function of the distance and the mass of gas released.     

Structural peculiarities of TiO2 and Pt/TiO2 catalysts for the photocatalytic oxidation of aqueous solution of Acid Orange 7 Dye upon ultraviolet light

TiO₂ (anatase) with different microstructure was synthesized by thermal hydrolysis of the titanyl sulfate and studied by X-ray powder diffraction, high resolution transmission electron microscopy and UV–vis diffuse reflectance spectroscopy. The effect of titanium dioxide structure, regular or distorted, on the photocatalytic degradation of Acid Orange 7 Dye (AO7) in water upon ultraviolet light was studied. It was found that synthesized TiO₂ possesses a relatively high reactivity when illuminated but also show different adsorption in the dark. The relationship between these behaviors depends on the real structure of the catalysts. Catalysts with a perfect structural ordering formed after heating at temperature higher than 500 °C show better photocatalytic performance. Small amount of Pt added into the TiO₂ structure was found to improve further the catalyst reactivity. Pt-modified titania catalysts oxidize AO7 more efficiently than P-25 Degussa TiO₂. Doping effect of Pt on the structural and photocatalytic properties of the samples is discussed.     

Sterol and fatty acid composition of neutral lipids ofParatenuisentis ambiguus and its host eel

The sterol composition of free sterol and steryl ester fractions of the fish parasiteParatenuisentis ambiguus was determined. In addition, the fatty acid composition of various neutral lipid classes, i.e., wax esters, steryl esters, triacylglycerols and free fatty acids, as well as the composition of the 1-O-alkyl moieties of total ether glycerolipids of the parasite, were investigated. The results of these studies were compared with those obtained on the intestinal tract tissue of its host, the eel (Anguilla anguilla). Cholesterol is the major sterol in bothP. ambiguus andA. anguilla. However, the sterols ofP. ambiguus contain high proportions (>20%) of other sterols, such as campesterol and various dehydrosterols. [e.g., 7-dehydrocholesterol and cholesta-5,22(E)-dienol]. The presence of these minor sterols agrees with the known biotransformations of exogenous sterols in various helminths. Considerable differences are found in the fatty acid composition of neutral lipid fractions, as well as the total lipid extract from the endoparasite as compared to the host tissue. In particular, eicosapentaenoic acid (20∶5n−3), other polyunsaturated fatty acids, such as 20∶4n−6, 22∶5n−3 and 22∶6n−3, as well as long-chain saturated fatty acids, such as 20∶0, are generally enriched in the neutral lipid fractions of the parasite as compared to those of infected eel intestine. The analysis of ether glycerolipids revealed that 1-O-hexadecyl (16∶0) and 1-O-hexadecenyl (16∶1) moieties were present in similar proportions in the ether lipids of bothP. ambiguus and eel intestine, whereas 1-O-octadecyl (18∶0) moieties are more prominent in the parasite and 1-O-octadecenyl (18∶1) moieties in the eel. The results of these studies show thatP. ambiguus has specific mechanisms for the regulation of the sterol and fatty acid composition of its neutral lipids. Dedicated to Professor Helmut K. Mangold on the occasion of his 70th birthday.     

Analysis of gas phase compounds in chemical vapor deposition of carbon from light hydrocarbons

Product distributions in the pyrolysis of ethylene, acetylene, and propylene are studied to obtain an experimental database for a detailed kinetic modeling of gas phase reactions in chemical vapor deposition of carbon from these light hydrocarbons. Experiments were performed with a vertical flow reactor at 900 °C and pressures from 2 to 15 kPa. Gas phase components were analyzed by both on-line and off-line gas chromatography. More than 40 compounds from hydrogen to coronene were identified and quantitatively determined as a function of the residence time varied up to 1.6 s. Product recoveries were generally more than 90%. Analysis of the kinetics of the conversion of the hydrocarbons resulted in global reaction orders of 1.2 (ethylene), 2.7 (acetylene), and 1.5 (propylene). First order dehydrogenation reactions and third order trimerization reactions leading to benzene are decisive reactions for ethylene and acetylene, respectively. Conversion of propylene should also be based on two simultaneous reactions, a first order dissociation reaction, and second order reactions such as bimolecular reaction of propylene resulting an allyl and a propyl radical. These insights should be useful to develop a reaction mechanism based on elementary reactions in forthcoming studies.     

Natural human–robot musical interaction: understanding the music conductor gestures by using the WB-4 inertial measurement system

This paper presents an inertial measurement unit-based human gesture recognition system for a robot instrument player to understand the instructions dictated by an orchestra conductor and accordingly adapt its musical performance. It is an extension of our previous publications on natural human–robot musical interaction. With this system, the robot can understand the real-time variations in musical parameters dictated by the conductor’s movements, adding expression to its performance while being synchronized with all the other human partner musicians. The enhanced interaction ability would obviously lead to an improvement of the overall live performance, but also allow the partner musicians, as well as the conductor, to better appreciate a joint musical performance, thanks to the complete naturalness of the interaction.