King furnace

The analysis of cometary data requires knowing the vibrational transition band strengths in the state of CN. Two very different values for the Einstein coefficient (A) of the fundamental 1-0 vibrational band have been reported one based on analysis of cometary data and the other from measurements in a King furnace.Using the CASSCF/MRCI dipole moment function, the computed /fjo value was in excellent agreement with the value measured in the King furnace. The small uncertainty in the computed value suggests that some of the assumptions in the model used to analyze the cometary data are in error. 

Molecule sources may be divided into three types thermal, supersonic jet, and cold collisions. Thermal sources (King furnace King, 1926 Broida oven West, et al, 1975 electric or microwave discharge Fehsenfeld, et al., 1965 static gas cell) are simple, convenient, and versatile. However, when the rotational partition function, kT/B, approaches 103, each vibrational band will contain many hundreds of rotational lines, the spectrum will become congested, vibrational bands will overlap each other, and analysis will be difficult. 

We then turn to a consideration of the absorption lines produced by the transmission of a continuous spectrum through an absorbing vapour. The concept of equivalent width is explained and we show that the equivalent width of an absorption line is determined by the product N.f..L. Details are given of the measurement of relative oscillator strengths by the absorption technique using a King furnace. 

Fig.10.5. Schematic diagram of King furnace and spectrometer for measurements of relative f-values by the absorption technique. (After Collins (1970).)...

A King furnace consists basically of a carbon tube... 

Discussion of some typical results. The equivalent width of an absorption linej such as that shown in Fig.10.6, may be obtained by integrating the area under the absorption profile. To obtain the oscillator strength from (equation (10.23>) it is necessary to know the density of absorbing atoms. Unfortunately in the King furnace the vapour density cannot be deduced from the measured temperature since the system is not in thermal equilibrium. 

Comparison of Study to Previous Work. The only work that can be compared to ours is that of Brenden and Chamberlain (6) using the same furnace and Chamberlain and King (7) using a different furnace. The assemblies used in these studies were of similar construction. The wall assemblies used contained fire-retardant-treated studs as the only combustibles. The interior and exterior sides were 5/8-in. (16-mm) type-X gypsum. Thus, heat release rates were understandably small. The onset of heat release started at 23 min after ignition. After that, a slow increase occurred, culminating to approximately 100 Btu/min ft2 (19 kW/m2) at 60 min. For an exposed area of 8 by 10 ft (2.44 by 3.05 mm), this would be 140 kW. 

Existence. The existence of C13 was first proved by King and Birge2 in 1929 with a remarkable spectrogram of carbon vapor obtained by heating carbon up to 2,500°C in an evacuated furnace. A banded spectrum was observed with its head at 4,737.0 A. This is the so-called Swan band which is prominent in all emission spectra of carbon flames and which is due to the radical C2. Just at the side of this band King and Birge found a much weaker band identical in pattern but with its head at 4,744.5 A. They interpreted the band properly as being due to the diatomic carbon molecule Cl2-C13. 

Al Graphite furnace atomic absorption spectrometry (GFAAS) GFAAS, Ultrafiltration GFAAS Human serum from patients on dialysis Human serum from patients on dialysis Human serum King et al. (1982) Gardiner et al. (1984) Leung et al. (1988)... 

Figure 22.13. Chromatograms of a standard mixture of polycyclic aromatic hydrocarbons and of a coke-furnace emission. From T. D. Searl, F. J. Cassidy, fV. H. King, and R. A. Brown, Anal. Chem., 42,954 (1970) by permission of the senior author and the publisher. Copyright 1970 by the American Chemical Society.

King Solomon s people swept up the white material present when a lake dries. They did not dig because they only wanted the material on the surface. They fired this material with sulfur, put silver on top of it and mixed in iron. Using this method and a reverberatory furnace, they poured 100,000 talents of gold. 

The basic concepts of atomic absorption spectrometry were published first by Walsh in 1955, this can be regarded as the actual birth year of the technique. At the same time Alkemade and Milatz designed an atomic absorption spectrometer in which flames were employed both as a radiation source and an atomizer. The commercial manufacture of atomic absorption instruments, however, did not start until ten years later. Since then the development of atomic absorption spectrometry has been very fast, and atomic absorption (AA) instruments very quickly became common. The inventions of dinitrogen oxide as oxidant and electrothermal atomization methods have both significantly expanded the utilization field of atomic absorption spectrometry. These techniques increased the number of measurable elements and lowered detection limits. Todays graphite furnace technique is based on the studies of King at the beginning of the twentieth century. 

The absorption cell. A few elements, such as the alkali metals, have appreciable vapour pressures at easily attainable temperatures and may be studied by using sealed absorption cells of glass or quartz. However, for astro-physical applications there is considerable interest in the elements of the first transition series, e.g. manganese, iron, cobalt, and nickel. For these elem.ents suitable vapour pressures are only attained at temperatures above 2000 K and the standard technique involves the use of a carbon furnace introduced by King (1922) as the absorption cell. At high temperatures, carbon is one of the few suitable materials since it reacts only slowly with most metals and has a low vapour pressure. 

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