Experimental study on a separate type thermosyphon

The passages of vapor flow and the returning liquid flow, are perfectly partitioned in a separate thermosyphon. Therefore the flooding limit can be eliminated, and practicability based on its construction is highly evaluated. In the present work, a container tube made of heat resisting glass, in which an electric heater is inserted, is selected as the heating section of the experimental equipment. Distilled water is used as the working fluid. The influence of the heater type, the diameter of evaporating section and the liquid fill charge on the heat transfer performance have been studied. The larger heat transfer coefficient is achieved in the case of the U type heater, the larger tube diameter and the less liquid fill charge of the evaporating section. The useful correlation equations of the heat transfer coefficient in the evaporator have been derived.

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Experimentelle Untersuchung an einem Trennstrom-Thermosiphon

Zusammenfassung In einem Trennstrom-Thermosiphon sind die Strömungskanäle für die Dampfströmung und den Kondensatrücklauf vollkommen separiert. Die Flutgrenze kann deshalb unberücksichtigt bleiben. In dieser Untersuchung dient ein temperaturbeständiges Glasrohr mit innenliegender Heizung als Wärmequelle. Arbeitsmedium ist destilliertes Wasser. Untersucht wurden der Einfluß des Heizelementtyps, des Durchmessers der Verdampferstrecke und der Füllmenge auf das Wärmeüber-gangsverhalten. Das U-Typ Heizelement liefert bei größerem Rohrdurchmesser und geringerer Füllmenge in der Verdampferstrecke die höchsten Wärmeübergangskoeffizienten. Für diese wurden Korrelationsgleichungen aufgestellt.

     

Photosensing Device Composed of Bilayer Membranes of Polymer-Pendant Ru(bpy)3 2+ and Prussian Blue

A photosensing device was fabricated based on a photochemical electron transfer reaction. A graphite electrode was coated with bilayer membranes of polymer-pendant Ru(bpy)₃ ²⁺ and Prussian Blue (PB) to give a bilayer-coated device. It was irradiated with visible light in an aqueous electrolyte and the induced photocurrent was measured as a function of the applied potential. The excitation of PB was responsible for the anodic photocurrent, while the excitation of the Ru complex mainly induced the cathodic photocurrent by an electron-transfer mechanism.     

Application of Polymer-Embedded Tris(2,2′ Bipyridine-Ruthenium(II) to Photodetection of Oxygen

A Nafion film containing tris(2,2′-bipyridine)ruthenium(II) as a luminescence probe was applied to photodetection of oxygen in a gas by utilizing the luminescence quenching by dioxygen. The linear Stern-Volmer plots of the emission intensity with respect to the oxygen concentration allowed quantitative determination of the oxygen. From the emission decay studied by a single-photon counting method, it was concluded that the quenching of the excited state Ru complex by oxygen proceeds by a conventional dynamic mechanism.     

Manganese(III)-Catalysed Oxidation of Sulphides with Sodium Chlorite in an Aprotic Solvent in the Presence of Alumina

A wide variety of sulphides can be readily converted to the corresponding sulphoxides in good to excellent yields by treatment with a combination of sodium chlorite, (salen)manganese(III) complex, and chromatographic alumina in dichloromethane under mild and neutral conditions.     

Effect of melt viscosity and surface tension of polymers on the percolation threshold of conductive-particle-filled polymeric composites

The electrical conductivities of carbon-black-filled low-density polyethylene (LDPE), poly(methyl methacrylate) (PMMA), and poly(vinyl chloride)-vinyl acetate (PVC/ VAc) copolymer were measured as functions of carbon content and melt viscosity of the matrix at the temperatures at which the composites were prepared. Sharp breaks in the relationship between the carbon filler content and the conductivity of composites were observed in all specimens at some content of the carbon filler. The conductivity jumps as much as 10 orders of magnitude at the break point. This phenomenon has been known as the “percolation threshold”. The critical carbon content corresponding to the break point