Efficiently activated carbon fiber derived from grafted novoloid fiber

Graft copolymerization of methyl methacrylate onto novoloid fiber was carried out by the electron beam mutual irradiation method. The characteristics of the grafted fiber were almost the same as those of the original novoloid fiber. The grafted fiber was carbonized and activated to yield an efficiently activated carbon fiber. The yield and the specific surface area of the activated carbon fiber, derived from the grafted novoloid fiber, were much greater than those derived from the original novoloid fiber. This is because grafted poly(methyl methacrylate) decomposes into monomer and gaseous products, forming pores on the surface and inside of the novoloid fiber on heating. © 1993 John Wiley & Sons, Inc.     

Development of automatic fault point locating and sectional isolating system for power distribution line

This paper describes the development of the Automatic Fault Point Locating and Sectional Isolating System. This system locates a single-line-to-ground fault point at each pole by using ground-current sensors, and isolates the faulted section by controlling pole switches with no outage of unfaulted sections. The ground-current sensor is connected to the line between allied ground terminals of pole devices and grounded conductor. It detects a ground fault current of more than 0.64 amperes that is determined so as to avoid an unexpected operation by stray current, but to detect the fault current accurately, and sends out an emergency signal with time delay of 0.1 s. Sectional isolation starts when both the emergency signal from the sensor and relay operation signals from a substation are received and ends within a feeder circuit-breaker tripping time of 1.5 s.     

Ethynylvinylidene

Ethynylvinylidene, an energetically low-lying isomer of diacetylene, has been studied using ab initio molecular electronic structure theory. Geometries of diacetylene, ethynylvinylidene, and the transition state between them have been optimized using the double-ζ plus polarization (DZP) and triple-ζ plus double polarization function (TZ2P) basis sets with the self-consistent field (SCF), configuration interaction with single and double excitations (CISD), coupled cluster with single and double substitutions (CCSD), and CCSD with perturbatively included connected triple substitutions [CCSD(T)] methods. At the TZ2P CCSD(T) level of theory only single point energies have been determined at the TZ2P CCSD geometries. Harmonic vibrational frequencies and infrared (IR) intensities are reported for the three stationary points at the DZP SCF, TZ2P SCF, and DZP CISD levels of theory. For ethynylvinylidene, rotational constants, dipole moments, and dipole moment components along the principal axes are also given. This isomer is found to be an extremely shallow minimum on the C₄H₂ potential energy surface, and the classical barrier to rearrangement (to diacetylene) is vanishingly small at the highest level of theory.     

The effects of nicorandil on electrophysiological changes in acute myocardial ischemia and reperfusion

This study was undertaken to clarify the effects of nicorandil on electrophysiological changes during acute ischemia and following reperfusion. We prepared an acute ischemic heart model by ligating the left anterior descending coronary artery in 27 dogs. After 10 minutes, reperfusion was performed. The changes in ventricular effective refractory period (ERP) and intramyocardial conduction time (ICT) were compared between the nicorandil group (n = 12) which received nicorandil intravenously before the coronary ligation and the control group (n = 15). In the control group, the ERP was shortened during ischemia, and rapidly shortened immediately after reperfusion, but was slightly prolonged 10 minutes after reperfusion. The ICT was prolonged during ischemia, but returned to the pre-ischemia value after reperfusion. In the nicorandil group, the changes in ERP and ICT were significantly inhibited compared to those in the control group. The incidence of ventricular fibrillation (VF) during reperfusion was 42% in the control group. However, there was no VF during reperfusion in the nicorandil group. Therefore, nicorandil may correct both the delayed conduction and the uneven ventricular effective refractory period detected during acute ischemia and following reperfusion, inhibiting the development of ventricular arrhythmia during reperfusion.     

Preservation of the ration of cerebral blood flow/metabolic rate for oxygen during prolonged anesthesia with isoflurane, sevoflurane, and halothane in humans

BACKGROUND: In several animal studies, an increase in cerebral blood flow (CBF) produced by volatile anesthetics has been reported to resolve over time during prolonged anesthesia. It is important to investigate whether this time-dependent change of CBF takes place in humans, especially in clinical situations where surgery is ongoing under anesthesia. In this study, to evaluate the effect of prolonged exposure to volatile anesthetics (isoflurane, sevoflurane, and halothane), the CBF equivalent (CBF divided by cerebral metabolic rate for oxygen (CMRO2) was determined every 20 min during anesthesia lasting more than 4h in patients. METHODS: Twenty-four surgical patients were assigned to three groups at random to receive isoflurane, sevoflurane, or halothane (8 patients each). End-tidal concentration of the selected volatile anesthetic was maintained at 0.5 and 1.0 MAC before surgery and then 1.5 MAC for the 3 h of surgical procedure. Normothermia and normocapnia were maintained. Mean arterial blood pressure was kept above 60 mmHg, using phenylephrine infusion, if necessary. CBF equivalent was calculated every 20 min as the reciprocal of arterial-jugular venous oxygen content difference. RESULTS: CBF equivalent at 0.5 MAC of isoflurane, halothane, and sevoflurane was 21 +/- 4, 20 +/- 3, and 21 +/- 5 ml blood/ml oxygen, respectively. All three examined volatile anesthetics significantly (P<0.01) increased CBF equivalent in a dose-dependent manner (0.5, 1.0, 1.5 MAC). AT 1.5 MAC, the increase of CBF equivalent with all anesthetics was maintained increased with minimal fluctuation for 3 h. The mean value of CBF equivalent at 1.5 MAC in the isoflurane group (45 +/- 8) was significantly (P<0.01) greater than those in the halothane (32 +/- 8) and sevoflurane (31 +/- 8) groups. Electroencephalogram was found to be relatively unchanged during observation periods at 1.5 MAC. CONCLUSIONS: These results demonstrate that CBF/CMRO2 ratio is markedly increased above normal and maintained during prolonged inhalation of volatile anesthetics in humans. It is impossible to determine whether these data indicate a stable CBF or whether CBF and CMRO2 are changing in parallel during the observation period. The unchanging electroencephalographic pattern suggests that the former possibility is more likely and that the increase of CBF produced by volatile anesthetics is maintained over time without decay, which has been reported in several animal studies. It also is suggested that isoflurane possesses greater capability to maintain global CBF relative to CMRO(2) than does halothane or sevoflurane. time.)     

Establishment of a modified rankine method for the separate determination of free and combined sulphites in foods. III

Summary Considerable improvements were made to the original Rankine method. Replacement of aspiration with an injection system contributed a great deal to the simplification of procedure, being accompanied with an increase in reproducibility. Air (flow rate 1.01/min) was used for injection because the use of inert gas gave little increase in recovery rate.Sodium bisulphite (free sulphite) and three kinds of combined sulphite compound (bisulphite adducts of acetaldehyde, pyruvic acid and D-mannose) were used to find the most suitable conditions for the separate determination of free and combine sulphites.Free sulphite was expelled from the sample by bubbling at 0 °C for 30 min. It was confirmed that no combined sulphite was dissociated under these conditions. The phosphoric acid concentration had an important role in the liberation of sulphite. When 25% phosphoric acid was used, more than 99% of free sulphite was expelled by cold bubbling and more than 99% of combined sulphite was recovered by heating afterwards for 10 min.The scope of the modified Rankine method was also extended to the determination of sulphite in concentrated orange juice.

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Verwendung der modifizierten Rankine-Methode zur getrennten Bestimmung von Sulfiten in Lebensmitteln. III

Zusammenfassung Die Rankine-Methode wurde bedeutend verbessert. Ein Umtausch der Aspiration mit Blasensystem trug beträchtlich zur Vereinfachung des Bestimmungsverfahrens bei, und die Reproduzierbarkeit wurde verbessert. Luft (Fließrate 1,01/min) wurde als Blasengas benutzt, da der Gebrauch von Inertgas für die Wiederfindungsrate unbedeutend ist.Natriumhydrogensulfit (freies Sulfit) und drei Arten gebundener Sulfite (Acetaldehydhydrogensulfit, Pyruvathydrogensulfit undd-Mannosehydrogensulfit) dienten dazu, die geeignetsten Bedingungen für die getrennte Bestimmung der freien und gebundenen Sulfite zu ermitteln.Freies Sulfit wurde bei 0 °C durch 30 min Durchblasen vertrieben. Hierbei ging kein gebundenes Sulîit verloren. Die Phosphorsäurekonzentration war wichtig für die Freisetzung des Sulfites. Wenn man 25%ige Phosphorsäure verwendet, werden > 99% freien Sulfites beim Durchblasen in der Kälte vertrieben, während > 99% gebundenen Sulfites durch nachheriges 10 min langes Erhitzen wiedergewonnen werden.Die modifizierte Rankine-Methode wurde weiterhin für konzentrierte Säfte verwendet.

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Studies on the Analyses of Sulphites in Foods (III)     

Morphology of composite film prepared by polymerizing styrene in poly(vinyl chloride) film

Styrene and the styrene-additive mixtures (kerosene, dioxane, ethylene dichloride, or dioctylphthalate) were soaked into a poly(vinylchloride) film and then styrene was polymerized. Subsequently, poly(styrene) was extracted with CCl₄ and the microporous membrane was obtained, of which the morphology was studied. It is elucidated that the additives affect the morphology of the resultant composite films.     

Retardation of the precipitation reaction by d.c. stress in an Al-12.5 wt % Zn alloy

The effect of direct electric current stress on the precipitation reaction in an Al-12.5 wt % Zn alloy was investigated by the resistometric method. It was found that the d.c. stress retarded the reaction rate as in the case of an Al-4 wt% Cu alloy. The dependence of the retarding effect on the annealing time and on the quenching temperature was examined on the basis of a model of current-assisted vacancy annihilation. The annealing temperatures after quenching were 30 and 40° C, and the quenching temperatures were varied from 300 to 500° C.     

Polymeric ultraviolet absorber

Polymeric fine powder, prepared by polymerization of glycidylmethacrylate–divinylbenzene, was reacted with 2,4-dihydroxylbenzophenone. The resultant polymer was effective as a polymeric ultraviolet absorber, and no migration was observed in polypropylene.