In recent years, various types of elastomeric isolators are used for seismic isolated buildings globally. International standards for elastomeric seismic-protection isolators, ISO 22762 were first developed in 2005, and this standard has been revised through a systematic review to issue the 3rd edition now (3rd edition was issued in October 2018). This paper describes breaking test results of elastomeric isolators to investigate the ultimate property (breaking limit) of isolators used for buildings around the world. Shear displacement capacity is one of the most important parameters of elastomeric isolators, and these tests results are useful for our proposal of the introduction of a classification system (classification of isolators according to their performance) to ISO 22762 in the near future. Breaking tests were carried out on 11 isolators produced in five countries. The isolators having diameters of around 800 mm, and the total rubber heights of around 160 mm were tested with increasing shear strain under constant compressive stress using a multi-axial testing system. The breaking shear strain was distributed between 300 and 450% or more.
A ribonucleoside 2',3'-cyclic phosphodiesterase (cyclic phosphodiesterase) having 3'-nucleotidase activity was purified from the cell-free extract of Bacillus subtilis var. amyloliquefacus, and its enzymatic properties were examined. The molecular weight was approximately 74,000. The enzyme was highly specific for ribonucleoside 2',3'-cyclic monophosphate (2',3'-cyclic mononucleotide), and ribonucleoside 3'-monophosphate (3'-mononucleotide), and also hydrolyzed bis p-nitrophenyl phosphate (bis p-NPP) but at a rate much slower than that of 3'-mononucleotide. Both cyclic phosphodiesterase and 3'-nucleotidase activities had an optimum pH of about 6.7, and phosphodiesterase activity against bis p-NPP indicated a relatively sharp pH optimum at 5.0. Only phosphodiesterase activity against bis p-NPP was greatly activated by Co2~, but both cyclic phosphodiesterase and 3'-nucleotidase activities were inhibited. However, Co2+ had an effect of protecting the enzyme against heat inactivation. 3'-Nucleotidase activity was not affected by EDTA, while phosphodiesterase activities against both 2',3'-cyclic mononucleotide and bis p-NPP were greatly inhibited. The enzyme hydrolyzed 3'-AMP with Km 0.046 mM and Vmax 1,585 µmol per hr per mg protein, bisp-NPP with Km 0.16 mM and Vn,a. 233 ,umol per hr per mg protein.In the course of studies on the physiological changes occurring after infection of Bacillus subtilis var. amyloliquefacus with phage, we became aware that a phosphodiesterase activity hydrolyzing bis p-nitrophenyl phosphate (bis p-NPP) under the acidic pH region (an optimal pH of about 5.0) exists in the phage uninfected cell-free extract, and that this activity did not change after infection of host cell with phage.In a preliminary experiment, attempts were made to characterize the substrate specificity using the enzyme partially purified by DEAF-cellulose chromatography.
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Im Rahmen der linearisierten Theorie der nichtstationären positiven Säule der Niederdruckentladung werden Ausdrücke abgeleitet, mit deren Hilfe aus Meßdaten für das Dispersions‐ und Amplifikationsverhalten laufender Schichten auf Kenngrößen der Elementarprozesse im Plasma geschlossen werden kann. Zu diesen gehören die Ionenbeweglichkeit, die Wärmeleitfähigkeit der Elektronen sowie die Konzentrations‐ und Elektronentemperatur‐Abhängigkeit der Ionisations‐ und der Energieverlustrate. Außerdem liefert die Theorie für die Resonanzschichtweite bei der Grenzstromstärke einen Minimalwert, der nicht unterschritten werden darf.
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