Low Pressure Vessel Research Articles

Fracture Initiation in Low Strength Steel Pressure Vessels

Tests to failure have been made on 5 ft dia × 1 in. thickness steel pressure vessels containing longitudinal slits through wall thickness representing natural defects. Steels of from 33,000 to 70,000 psi yield strength have been tested over a range of temperatures with defects of 6, 12 and 24 in. length. When the toughness exceeds 20/30 ft lb Charpy V-notch energy, failure occurs by plastic collapse, and failure conditions can be predicted from the tensile properties of the steel. At lower levels of toughness the concept of a constant crack opening displacement (COD) at fracture initiation of defects in pressure vessels and in notched bend specimens can be used to predict vessel failure conditions. Recognition must be made of the variables found in COD notched bend testing, and tests are necessary to determine the most embrittled area of a pressure vessel. Examples are given of the method of application of COD and the degree of embrittlement possible in a low alloy steel.

INFERIOR VENA CAVAL COMPRESSION

INFERIOR VENA CAVAL COMPRESSION THE PSEUDO-OBSTRUCTION SYNDROMEJOHN DOPPMAN, M.D., H. THOMAS FOLEY, M.D. and WILLIAM HAMMOND, M.D.Audio Available | Share

低圧気中におけるプラズマジェットの磁場中の諸特性(第1報)

In the welding technology, it may be interesting to examine the magnetic control of a plasma jet flame. In this report is described the experimental result on the fundamental properties of plasma jet flame in a magnetic field.The distribution of field strength in the cusp type or mirror type magnetic field, each of them were made by two coils Ml and M2, was measured as a preliminary research. The plasma jet was injected to the low pressure vessel along the axis of magnetic field, as shown in Fig. 1.Photographic observations show that the plasma jet flame flows in the direction of magnetic line of force. Radial distribution of total pressure of the plasma jet flame was measured with use of a pitot tube on the mid-plane between coil Mt and coil M2. In general, the total pressure of plasma jet in the mirror type magnetic field was higher than that in cusp type field. Higher values were observed at relatively constricted region near the central axis of plasma jet.Total pressure rises as the are current incrases, but is almost invariant with the arc voltage in this experiment.The thermal efficiency of the plasma jet torch was also investigated. The amount of energy contained in plasma flame is expressed as ηVI, η being thermal efficiency of torch.It has been found that the total pressure varies with the amount of plasma energy ηVI.

Measurements of the Charged Particles of an Equilibrium Turbulent Plasma

A pair of diagnostic techniques for the measurement of the statistical properties of the ionized particles of an equilibrium turbulent plasma have been developed including an electrostatic probe and a high-resolution microwave probe. The turbulent plasma is formed by seeding a premixed ethylene-oxygen flame in a combustion chamber and then exhausting through an expansion nozzle into a low-pressure vessel. The power spectral density of the fluctuations of the electrons and ions is measured. The electron and ion fluctuations are observed to have the identical spectrum. The ion density correlations in space and space-time have been measured throughout the plasma volume. The distribution of the mean and rms values of the electron density throughout the volume is also presented. It is concluded that on the axis of the hot jet exhaust the turbulent eddy pattern is approximately isotropic and frozen.

Filling and emptying of the low-pressure blood vessels of the human forearm.

Filling and emptying of the low-pressure blood vessels of the human forearm.

Distensibility of low-pressure capacitance blood vessels of the forearm in patients with vasoregulatory asthenia

Distensibility of low-pressure capacitance blood vessels of the forearm in patients with vasoregulatory asthenia

Distensibility of digital blood vessels in cold environment.

To determine finger-tip vascular distensibility when all of the vessels are subjected to a uniform pressure, an appropriate plethysmograph is used to follow the increase after local venous occlusion. When the finger shows no further systematic increase in volume (volume B), an arterial occlusion is applied to the upper part of the arm. Blood will then flow from the high pressure parts of the vascular bed of the finger tip until the pressure level is related to the venous occlusion cuff pressure to give a new volume (C). Release of the venous occlusion cuff permits all of the blood vessels in the finger tip to come into equilibrium with the pressures in the vessels of the arm to give a measure of the volume (D) contained at the low pressure. The difference between volumes C and D represents the distention of the entire vascular bed of the finger tip for the pressure difference between the occlusion and the final static pressure level. When subjects are exposed to a cold environment, distensibility of the finger-tip vessels decreases, with evidence for involvement of both high- and low-pressure vessels. Submitted on September 19, 1960

Surgical obliteration of a coronary artery fistula to right ventricle.

Aneurysms of the coronary arteries are not common. Since the first report of surgical correction of an anomalous coronary artery-intracardiac shunt by Bjork and Crafoord1in 1947, however, the volume of literature dealing with this subject is growing, a manifestation of the increasing interest in the nature of the functional defect produced by these lesions. In a recent editorial, Edwards2reviewed the anomalies of the coronary arterial system and a plea was made that such anomalies be classified by functional rather than by older anatomical criteria. It was urged that those anomalies with communications between a coronary artery and a low-pressure cardiac chamber or vessel (an intracardiac arteriovenous shunt) comprise the important group of defects to recognize. These lesions carry a serious threat to the patient's health, yet the majority could be corrected by surgical interruption of the shunt. Steinberg et al.3present a comprehensive review of