Wood's Tube Research Articles

Design and manufacturing of wood filled steel tubes for structural applications

Abstract Wood filled steel tubes are very effective and find applications in building and construction activities. The composite action between wood and steel tube is function of interference and friction between wood and steel tube, which induce residual stresses on wood and steel tube. The bond and gripping strength between wood and steel tube affects the strength properties of wood filled steel tubes. The objectives of this paper are set from point of design and construction of wood filled steel tube. To design tolerance value on wood to obtain effective confinement between wood and steel tube. Experimentally determine coefficient of friction between steel tube and wood. Determine the stresses induced in wood and steel tube due to interference of wood and steel tube. Determine bond strength and gripping strength by push out tests to understand the confinement and composite action between wood and steel tube.

Spectroscopic study of a wood's tube discharge in hydrogen

The atomic and molecular spectra generated by a Wood's tube discharge in hydrogen, operating at 2 kV, 20 mA and a nominal gas pressure of 0.2-0.6 torr, are described and discussed. Molecular impurity spectra include the second positive system of N 2 and the violet system of CN, which is a prominent feature of cometary spectra. A coronal type model is outlined for explaining the observed intensities in the hydrogen Balmer series and in the triplet and quintet systems of O I.

A high-density effusive target of atomic hydrogen

The design and construction of a DC discharge (Wood's tube), used as source for an atomic hydrogen target in collision experiments with multiply charged ions, is described and the characteristic parameters (nozzle diameter, wall temperature, pumping speed, discharge tube preparation and discharge pressure) are investigated. The ratio obtained for the atomic and molecular hydrogen target thickness was of the order of four in the collision region. The target thickness of the atomic hydrogen could be varied between 5*1016 m-2 and approximately 3*1017 m-2. The effectiveness of the arrangement is demonstrated by charge transfer measurements of multiply charged Krq+ ions in atomic hydrogen.

Design of a high density atomic hydrogen source and determination of Balmer cross sections

A high density beam of atomic hydrogen was obtained from a Wood discharge and utilized in the measurement of electron-hydrogen atom collision cross sections. Balmer optical excitation cross sections were determined from observations of crossed electronic and atomic beams. In order to choose Wood discharge parameters to obtain a high degree of dissociation under conditions of a high gas throughput, the differential equations relating the production, loss, and flow of hydrogen atoms and molecules were formulated and solved. The solutions show that recombination of atoms on the metal electrodes greatly reduces the degree of dissociation in large diameter tubes. They further show that this effect can be nearly eliminated by placing short small diameter tubes, called constrictions, between the electrodes and the main tube. A Wood tube 2 cm in diameter and 2 m in length with these constrictions was constructed which produced an atomic to molecular density ratio of 11 at a throughput of 1000 mtorr · liter/sec. The atoms and molecules from the Wood tube were passed through a nozzle and formed into a beam which was crossed with a monoenergetic electron beam. In the crossed beam volume the atomic density was approximately 5.6×1012 cm−3 and the background molecular density was approximately 3.3×1013 cm−3. Optical excitation data were obtained by observation at 90° to the crossed beams with a monochromator and photomultiplier detection system. The ratio of the atomic density with the Wood discharge on to the molecular density with the Wood discharge off in the crossed beam volume was determined from molecular light intensity measurements and a derived relation. Combining this ratio with Balmer optical excitation data with the Wood discharge on and off gave the ratio of the atomic and molecular Balmer cross sections. Absolute molecular Balmer cross sections were measured in a static gas apparatus for use in determining the absolute atomic Balmer cross sections. The atomic Balmer cross sections (in units of 10−20 cm2) for Hα, Hβ, Hγ, Hδ, and Hε at 200 eV thus determined are 229.0, 72.4, 22.5, 12.9, and 6.5, respectively. All of these cross sections are within 23% of the theoretical optical cross sections determined under zero electric field conditions.

Reaction of hydrogen atoms with halogeno-methanes. Part 1.—Carbon tetrachloride

Hydrogen atoms, generated in a Wood's tube, have been allowed to react with carbon tetrachloride vapour. The products of the reaction have been analyzed and found to be hydrogen chloride, chloroform, methylene dichloride and traces of methyl chloride. The effect of the relative concentrations of the reactants, of an inert gas and of added hydrogen chloride on the ratio of the principal products has been investigated. From these data it is possible to build up a complete picture of the reaction sequences. The initial step is chlorine abstraction by a hydrogen atom; the trichloromethyl radical so produced reacts with a further hydrogen atom to yield an excited chloroform molecule which either undergoes collisional deactivation or loses hydrogen chloride to yield dichlorocarbene.

Gastric mucosa in acute duodenal ulcer.

This study was undertaken to determine the status of the gastric mucosa in duodenal ulcer patients during a phase of active symptoms and after a period of treatment and subsidence of symptoms. We were interested in assessing any role of gastritis in the acute symptoms and in determining whether the development of histological alterations in the gastric mucosa was in any way related to subsidence of duodenal ulcer symptoms. The gastric mucosa of duodenal ulcer patients has been studied in operative and postmortem specimens and, more recently, by means of the vacuum biopsy tube. The gastric mucosa was normal in 19 out of 34 duodenal ulcer patients studied by vacuum biopsy.1In 97 cases of duodenal ulcer, Wood's tube biopsy revealed normal gastric mucosa in 60.2%, superficial gastritis in 34.7%, and atrophic gastritis in 5.1%.2 Examination of stomachs of duodenal ulcer patients at surgery or postmortem examination usually

Reactions of Sodium with Active Oxygen

IN a recent investigation of the chemiluminescent flame formed when sodium diffuses into hydrogen coming from a discharge, Polanyi and Sadowski1 found that the sodium was being consumed at a rate which was 104–105 times faster than could be accounted for on the basis of ternary reactions. Since electronically excited hydrogen could be excluded as a reagent, they accounted for the sodium consumption in terms of the binary reaction: where H2 † (v≥ 6) refers to molecular hydrogen in at least the sixth vibrational level of the ground electronic state. In the present work, the depletion of sodium in an atmosphere of active oxygen produced in a Wood's tube discharge was measured by means of the Polanyi sodium diffusion-flame technique2. The apparatus has been previously described1. Argon was used as a carrier gas for the sodium vapour.

Diagnosis of gastric malignancy by blind gastric biopsy.

Two cases have been reported in which a histologic diagnosis of carcinoma of the stomach was made by means of biopsy by the Wood's tube.

A Reversible Discharge Tube

R. W. WOOD1 has described an interesting discharge tube which could be made to exhibit “either the spectrum of atomic hydrogen or molecular oxygen at will” on excitation by a high-frequency discharge. In the course of investigations on the spectra of gases excited by high-frequency discharge, we have prepared a discharge tube which has an analogous behaviour and can be made to show either the air spectrum or hydrogen spectrum as desired. The fundamental difference between the two tubes, however, is that under the discharge hydrogen is suppressed by oxygen in Wood's tube, whereas here, hydrogen suppresses air.

Raman spectra of certain organo-metallic compounds

The Raman effect in a large variety of substances, both organic and inorganic, has been studied in detail in relation to molecular structure. There is, however, an important class of organo-metallic compounds, namely, the metallic alkyls, etc., that have not been properly studied. These compounds would be of special interest, firstly, in view of the peculiar nature of the chemical bonds between carbon and the metallic atoms, and secondly, because of the effect of the very large mass of the metallic atoms on the frequencies of oscillation. The dearth of investigations on these compounds is due mainly to the extremely poisonous nature of their vapours and the spontaneous inflammability of some of them in air. Using a special technique, the Raman spectra of the following compounds of the above class have been studied by the present writer, namely, of zinc dimethyl and diethyl, mercury dimethyl and diethyl, bismuth trimethyl, tin tetramethyl and lead tetraethyl. This paper gives an account of these investigations. 2-Experimental The liquids were contained in the usual double-chambered vessel consisting of a flask intended to contain the undistilled liquid, and a cylindrical Wood's tube into which the liquid is distilled over from the flask.

The Continuous Spectrum of Hydrogen

Effect of the source on the continuous spectrum of hydrogen---The continuous spectrum of hydrogen is observed to be of similar character, although of differing intensity, in a number of sources, a Wood tube, an ordinary discharge tube, the separate striations of the positive column, the condensed spark in hydrogen at pressures above atmospheric, and in the water spark. It is of appreciable intensity near $H\ensuremath{\alpha}$, rises slowly to a maximum in the near ultra-violet and descends slowly in intensity from $\ensuremath{\lambda}300$ to 220\ensuremath{\mu}\ensuremath{\mu}.Theory of the continuous spectrum of hydrogen.---Bohr's idea, which attributes a continuous spectrum near the Balmer lines to an electron plunging from an unquantized energy region to the second orbit, together with Wright's theory that such unquantization may exist from any given orbit outwards, is given statistical formulation on the assumption that the plunging electrons obey a Maxwellian law of distribution. A formula for the distribution of energy across the continuous spectrum is obtained which involves an unknown probability, ${a}_{n}$, that the atom exist through the $n\mathrm{th}$ orbit, the region beyond being unquantized. When ${a}_{n}$ is evaluated roughly from general physical considerations the formula agrees qualitatively with the continuous spectra observed in the hydrogen stars and the laboratory sources. It is recognized that the theory is a simple type of the more general theory of retardation spectra.