- Home
- A-Z Publications
- Platinum Metals Review
- Previous Issues
- Volume 15, Issue 3, 1971
Platinum Metals Review - Volume 15, Issue 3, 1971
Volume 15, Issue 3, 1971
-
-
The Stability of Metal-sheathed Platinum Thermocouples
Authors: By G. L. Selman and R. RushforthThe instability sometimes encountered in metal-sheathed noble metal thermocouples used for long periods at temperatures above 1300°C is attributable to the presence within the sheath of mixed platinum and rhodium oxide vapours from which the pure platinum limb can take up rhodium. Such instability can be avoided by removing residual air from the sheath and substituting an inert gas before the assembly is hermetically sealed. Couples sheathed and sealed up in this way have thermoelectric stabilities comparable to those of the normal unsheathed thermocouple where natural convection prevents the accumulation of dangerous concentrations of rhodium oxide vapour. In the absence of oxygen, the deleterious effects of rhodium metal vapour migration upon the thermoelectric output of these devices can be reduced to negligible levels by suitably selecting the alloys from which the thermocouple and its sheath are constructed. This article is based upon a paper presented to the Fifth Symposium on Temperature, Its Measurement and Control in Science and Industry, held last month in Washington, D.C.
-
-
-
Heterogeneous Catalysis in the Liquid Phase
Authors: By E. Shutt and J. M. WinterbottomThe number of parameters affecting the rate and possibly the mechanism of a liquid phase, heterogeneously catalysed reaction is very much larger than that for the analogous gas phase reaction. The hydrogenation of two alkynes has been studied using a palladium oxide catalyst, in a number of solvents, in order to discover the effect of the latter upon the rates of reaction. It was hoped that results of general applicability to other liquid phase heterogeneously catalysed systems might be obtained. In this context, surface- and diffusion-controlled regimes have been identified, pronounced solvent effects were observed and attempts have been made to measure hydrogen concentrations in solution under reaction conditions.
-
Volumes & issues
-
Volume 58 (2014)
-
Volume 57 (2013)
-
Volume 56 (2012)
-
Volume 55 (2011)
-
Volume 54 (2010)
-
Volume 53 (2009)
-
Volume 52 (2008)
-
Volume 51 (2007)
-
Volume 50 (2006)
-
Volume 49 (2005)
-
Volume 48 (2004)
-
Volume 47 (2003)
-
Volume 46 (2002)
-
Volume 45 (2001)
-
Volume 44 (2000)
-
Volume 43 (1999)
-
Volume 42 (1998)
-
Volume 41 (1997)
-
Volume 40 (1996)
-
Volume 39 (1995)
-
Volume 38 (1994)
-
Volume 37 (1993)
-
Volume 36 (1992)
-
Volume 35 (1991)
-
Volume 34 (1990)
-
Volume 33 (1989)
-
Volume 32 (1988)
-
Volume 31 (1987)
-
Volume 30 (1986)
-
Volume 29 (1985)
-
Volume 28 (1984)
-
Volume 27 (1983)
-
Volume 26 (1982)
-
Volume 25 (1981)
-
Volume 24 (1980)
-
Volume 23 (1979)
-
Volume 22 (1978)
-
Volume 21 (1977)
-
Volume 20 (1976)
-
Volume 19 (1975)
-
Volume 18 (1974)
-
Volume 17 (1973)
-
Volume 16 (1972)
-
Volume 15 (1971)
-
Volume 14 (1970)
-
Volume 13 (1969)
-
Volume 12 (1968)
-
Volume 11 (1967)
-
Volume 10 (1966)
-
Volume 9 (1965)
-
Volume 8 (1964)
-
Volume 7 (1963)
-
Volume 6 (1962)
-
Volume 5 (1961)
-
Volume 4 (1960)
-
Volume 3 (1959)
-
Volume 2 (1958)
-
Volume 1 (1957)