Sodium-potassium Alloy Research Articles

Solution of Pulp Tissue by Chemical Agents

The elimination of necrotic pulp tissue from the root canal is important for the ultimate success of a root-canal operation. To attain this end, both mechanical and chemical means are employed. Among chemical agents used for this purpose may be mentioned sulfuric acid (Callahan'), sodium-potassium alloy (Schreier2), sodium dioxide (Kirk3), sodium methylate (Levene4), papain (Wilkinson 5) and chlorinated soda solution (Walker6). Solutions of hydrochloric acid, sodium hydroxide and potassium hydroxide have also been used and advocated for disintegration or solution of pulp tissue. Of historical rather than practical interest is the use of maggots for cleansing the canal of necrotic tissue, as suggested by Dreher. 7 The purpose of this study was to determine which of the agents already mentioned, or others believed to have a solvent action on tissue, is more effective. Sponer, 8 Blum 9 and Holst and Pedersen ~~ undertook somewhat similar studies, limiting themselves to fewer chemical agents or including proprietary agents not known in this country. M E T H O D

The emission of electrons under the influence of chemical action. Part II.—Some general conclusions and a further study of the case of carbonyl chloride

We have now investigated this effcet on the sodium potassium alloy K 2 Na for 22 different gases. With 15 of these tbs emission has been found to be sufficiently large for the distribution of kinetic energy among the emitted electrons to be determined, using the reacting gases at pressures of the order of 10 -5 mm of mercury. As a result of these experiments we have been led to some general conclusions, the most important of which we propose to state, very briefly, at the outset. They are:— (1) The energy distribution is not in general of the Maxwellian type as the earlier evidence bad tended to indicate. We expressed a suspicion of the correctness of this view on p. 49 of our previous paper. The later experiments have confirmed that suspicion.

Photoelectric Emission as a Function of Composition in Sodium-Potassium Alloys

The entire series of alloys of sodium and potassium have been investigated with respect to the relative values of the photoelectric currents produced by light polarized with the electric vector in and at right angles to the plane of incidence. The pure metals when molten exhibit values below three for the ratio of the two emissions; the alloys show three maxima at compositions approximately 20, 50, and 90 atomic percent of sodium, with values from 10 to 30 for the ratio: the minima between show low values approximating those for the pure metals. The maxima and minima of the ratio of emissions are due to complicated variations in magnitude of the two emissions compared.

The Free Electron Characteristics of Sodium-Potassium Alloys

The Free Electron Characteristics of Sodium-Potassium Alloys

The Optical Constants of Sodium-Potassium Alloys

The optical constants of sodium-potassium alloys were investigated for an entire alloy series by the polarimetric method. Bright metallic surfaces were obtained by filling glass cells with the molten metal in a vacuum. Excepting sodium, all the specimens were observed in the liquid form. In the region near the composition corresponding to NaK the refractivity-concentration curve has a maximum value of 0.137 and the absorptive index-concentration curve has a minimum value of 12.5. The effect of change in temperature was studied for some of the mirrors. The solid alloy containing 83 per cent. Na showed a change in the optical constants with a change in temperature, but no change was found for the liquid alloy containing 26 per cent Na. It could not be definitely determined whether the change observed for the solid alloy was due to a change in the optical constants or was due to a possible surface effect resulting from the metal expanding and making better contact with the glass.

A Sodium Vapour Electric Discharge Tube

A simple method of producing a bright source of sodium radiation is described. An electric discharge tube of quartz, having a pool of sodium-potassium alloy as one electrode, and an iron rod as the other electrode, is utilised. The sodium vapour is proeduced by gently heating the lower part of the tube, containing the alloy, over a ring gas burner concentric with the tube. When an electric discharge is passed, a bright yellow light is emitted. This light consists almost entirely of the D lines. Any gases present in the tube are absorbed by the alloy while the discharge is passing. No continuous pumping is necessary to keep the tube exhausted, and the experiment works best when the temperature of the sodium vapour is 250?C.

On the Photoelectric Effect of Sodium-potassium Alloy and its Bearing on the Structure of the Ether

On the Photoelectric Effect of Sodium-potassium Alloy and its Bearing on the Structure of the Ether