Die Adsorptionstechnik – ein Gebiet mit Zukunft

Adsorption 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.     

Realization of a 450 mhz cable tv system compatible with existing networks

This paper describes the realization in West Germany of a 450 MHz cable TV system, which matches into the infrastructure already formed by the existing 300 MHz systems. The studies and developments done to achieve this are described, and the results of a field trial detailed. Finally the impact of the new MAC standard is discussed.     

The interaction of pulsed electric fields and texturizing ‐ antifreezing agents in quality retention of defrosted potato strips

The combination of pulsed electric fields (PEF) and texturizing and antifreeze agents on quality retention of defrosted potato strips were studied. Potato strips (10 mm thickness, 100 g) were placed in different solutions (1% w/v) of CaCl₂, glycerol, trehalose as well as NaCl and sucrose, treated with PEF (0.5 kV cm^?1, 100 pulses, 4 Hz). Then, all the samples were soaked in the same solutions for 10 min. After draining, samples were packed into polypropylene pouches and stored at ?18 °C for 12 h. Samples were thawed out at room temperature (20 °C) in 3 h. Untreated controls and PEF treated control samples were also frozen and thawed in similar conditions. To assess the potato strip quality, the thawed samples were analysed for moisture content, weight loss, firmness and colour attributes. The results indicate that PEF treatment by itself is not a suitable pre‐treatment method for frozen potato strips and should be assisted by CaCl₂ and trehalose treatment to prevent softening after defrosting. Firmness analyses determined that application of PEF alone results in 2.38 N. However, PEF in combination with CaCl₂ and trehalose result in 2.97 N and 2.99 N, respectively, which are both significantly firmer than the samples solely treated with PEF. CaCl₂ and trehalose were effective in not only maintaining the structural integrity of the cells, but also retaining colour attributes. The L* value was found to be higher (P < 0.05) in CaCl₂ and trehalose treated samples (58.95 and 57.21, respectively), as compared to PEF treated samples (53.97) denoting a darker colour. Application of CaCl₂ and trehalsoe in combination with PEF also resulted in significantly less weight loss after thawing.     

2-Amino-3-substituted-6-[(E)-1-phenyl-2-(N-methylcarbamoyl)vinyl]imid azo[1,2-a]pyridines as a novel class of inhibitors of human rhinovirus: stereospecific synthesis and antiviral activity

A series of 2-amino-3-substituted-6-[(E)-1-phenyl-2-(N-methylcarbamoyl)vinyl]+ ++imid azo[1,2-a]pyridines 1a-i, structurally related to Enviroxime and its analogous benzimidazoles, was designed and prepared for testing as antirhinovirus agents. The imidazo ring in this class of compounds was constructed starting from the aminopyridine after tosylation and subsequent treatment with the appropriate acetamides. The key steps in the synthesis include the development and use of a new Horner-Emmons reagent for the direct incorporation of methyl vinylcarboxamide. The reaction was stereospecific in the substrates 5a-f leading exclusively to the desired E-isomer and avoiding the use of reverse-phase preparative HPLC for the separation of both possible isomers before antiviral activity evaluation. The isopropylsulfonyl group, known as the best substituent at the 1-position in the benzimidazole SAR in terms of activity, was introduced in this new series of imidazo[1,2-a]pyridines via halogen-metal exchange and subsequent treatment with isopropyl isopropanethiolsulfonate. Compounds 1a-i were evaluated in plaque reduction assay and in a cytopathic effect assay. Compounds 1b-d,h exhibited a strong antirhinovirus activity, and no apparent cellular toxicity was visible. The substitution at the 3-position was required for activity. Surprisingly the isopropylsulfonyl in this family of compounds did not enhance the activity as in the case of benzimidazoles. Instead, compound 1i was 4 times less active than its phenyl and sulfide partners. The chemistry as well as the biological evaluation are discussed.     

Über die Spannungsverteilung in Zahnstangen

Zusammenfassung Mit Hilfe komplexer Rechenverfahren werden exakte Spannungsfunktionen gewonnen, die für die Spannungsverteilung in Zahnstangen mit beliebigem Profil und bei beliebigem Kraftangriff zu neuen Berechnungsgrundlagen führen.     

Constant level lubricators and other bearing protection devices: how smart retrofits will improve equipment reliability

To this day, some important lubricant application and bearing protection issues are still being overlooked or misunderstood in the typical modern process plant environment. Satisfactory explanations are not forthcoming, leading the industry to loose faith in equipment reliability. Heinz P Block sees if he can find a solution.     

Mathematical Description of Experimentally Determined Charge Distributions of a Unipolar Diffusion Charger

The charge distributions of an improved opposed flow unipolar diffusion charger were measured using a tandem differential mobility analyzer (DMA) set up in a size range of approximately 20–400 nm. The charger is intended to be used in a portable aerosol sizer to measure particle size distributions. The determined charge distributions were represented by lognormal distributions, and a set of equations and coefficients was developed to calculate the charge distributions. These equations can be easily implemented in software for size distribution measurements. The agreement between the mathematically derived and measured charge distributions is very good, with regression coefficients R ² > 0.96. The investigations showed that approximately 55% of 20-nm particles remain uncharged, while up to 25 elementary charges need to be considered for multiple charge correction of 400-nm particles. Comparison with the Fuchs theory delivered satisfying agreement with the measured average charge levels, but charge distributions cannot be described by the Fuchs theory, likely caused by the charger geometry.

Copyright 2012 American Association for Aerosol Research     

Sintered Halon as a diffuse reflecting liner for light integration boxes

Sintered Halon G-80, a polytetrafluoroethylene (PTFE) resin available commercially in powdered form, is a superb diffuse reflector. Sintered Halon has 96% absolute reflectance at wavelengths between 300 nm and 380 nm, and about 98% absolute reflectance above 380 nm. It is chemically inert, is mechanically strong, does not fluoresce, and the high reflectance is easy to maintain over time. We have used sintered Halon as a lining in light integration boxes of water Cherenkov detectors. Preparation involves packing Halon powder into a mold to a specific density, then heating the material almost to the melting point (sintering). A method of preparing sintered Halon is presented. Physical properties of sintered Halon have been measured and we present those results here as well.     

Analysis of recovery from behavioral asymmetries induced by unilateral removal of vibrissae in the rat.

Unilateral removal of vibrissae in rats induces an asymmetry in the side of the face used to scan the wall while traversing the edge of an open field (thigmotactic scanning). This behavioral asymmetry recovers over time. The time course of asymmetry and recovery was systematically analyzed by testing groups of rats deprived of vibrissae for different periods of time. The preferential use of the hemiface with intact vibrissae persisted up to 3 days after vibrissae removal. It was expressed maximally during the first minute of testing. This phase was followed by a rapid return to symmetry by Day 6. Recovery to symmetry involved both a decrease in duration of scanning with the vibrissae-intact side and an increase with the vibrissae-clipped side of the face, with the total duration remaining constant throughout the states of asymmetry and recovery. The time course of behavioral recovery corresponds to the time course of neural plasticity in the basal ganglia that accompanies hemivibrissotomy, a result suggesting a functional link between the two phenomena. (PsycINFO Database Record (c) 2010 APA, all rights reserved)