Properties of materials under hydrothermal conditions. I. Permeation of hydrogen through gold membrane

Permeation rate of hydrogen through a gold cell made as a reaction vessel for a Dickson-type hydrothermal apparatus was measured at 50°intervals from 300°to 450℃ under a hydrothermal condition. The gold cell chosen for the measurement had a shape and size illustrated in Fig. 1 when it was fully expanded, and was a typical one in the meaning that it had been used several times for hydrothermal experiments (its total history may be equivalent to one month at 490℃) and that it had a body enlarged by about 8% in diameter from the original size as a result of pinhole check made by applying a gas pressure to the inside. The cell was filled with an appropriate amount of pure water, placed in a pressure vessel made of Ni-base alloy, pressurized by injecting water to the outside of the cell and kept under predetermined temperatures and pressure (=1 kbar). Meanwhile, small fractions of the waters inside and outside the cell were sampled at times and analyzed for H(2) gas-chromatographically as described in ref. (5). H(2) concentrations in the samples (CH(2)) were converted to H(2) fugacity values by using the conversion factors (Y) given in ref. (6). At each temperature, the permeation rate (k) of H(2) through the cell is evaluated by correlating the measured fH(2) values with time (t) according to eq. (2), where fo is the fH(2) in the outer water and is a constant, and fi and m are the fH(2) in and the mass of the inner water, respectively. The relevant data and results are shown in Table 1. The present data for the permeation rate φ, expressed in c㎥ H(2) at STP per 1c㎡ surface area, 1 mm wall thickness, 1 (bar)(1/2) of (fH(2))(1/2) difference and 1 hour, are plotted in Fig. 2 in relation to 1/T (K) and compared with one available data, which is a combination of reported solubility and diffusion coefficient data for hydrogen into gold at higher temperatures. The present data can be fitted into eq. (3). The present result may be of importance for hydrothermal experimental studies of geochemical redox reactions and of hydrogen isotope exchange reactions, and the technique used may also be important as a new, simple method of measuring hydrogen permeability through noble metals

Sub-harmonic Oscillations in Three-phase Circuit

Sub-harmonic resonance in a three-phase circuit related with a power circuit with series capacitors is studied. The paper describes that the equations which govern the oscillations in the system are under some restrictions transformed to the form : and the internal resonance of this system is correlated with the sub-harmonic resonance which occurs in the original three-phase system. An analog computer study on this problem is included

A Method for Analysing Parametrically Excited System by Matrix Function

This paper describes a method for analysing parametrically excited system of higher order. The method is based on the theory of matrix function and the discrete Fourier transform. As a numerical example, we deal with a kind of Hill's equation derived from the synchronous generator circuit with unbalanced capacitive load and give its stability charts

Digital Simulation of Hysteretic Loop by Preisach Diagram

This paper proposes a method for a digital simulation of hysteretic loops based on the use of the Preisach diagram. The hysteretic characteristic is expressed by an integral equation the kernel of which is discretely given. As examples, using the method proposed, we obtain the major loop, minor loop and so forth

The strength of welded flame-cut columns of astm A572 steel

This thesis describes the results of an extensive investigation into the strength and behavior of steel wide-flange columns welded from flame-cut plates. The material chosen for the study is ASTM A572 (Grade 50) steel

Applications of Fourier Series Technique to Inverse Laplace Transform : Part II

This paper describes some basic properties of the Fourier series, the finite Fourier approximation and the method of applying them to the numerical analysis of the Laplace transform. Some considerations of error analysis in numerical treaties and some numerical examples are given

Matric Operational Calculus and Its Applications : Part II

This paper describes the fundamental properties of the operational calculus based on the Mikusinsky's method for the matrix functions (sequences and series of operators, operational functions and their derivatives), and then, presents the analysis of the multi-conductor transmission systems for its applications

Analysis of Nonlinear Oscillations in Three-phase Circuits by Discrete Fourier Transform

A method for analysing the nonlinear oscillations in three-phase circuits with nonlinearities of polynomials of a high degree is presented by use of the discrete Fourier transform (DFT). The stability of the oscillation is investigated by means of the DFT. Furthermore, this paper describes how to determine the sampling rate. Numerical examples by the conventional Fourier series method are compared

1/3-harmonic Oscillation in Three-phase Circuit with Series Condensers

The 1/3-harmonic oscillation originated in the three phase circuit with series condensers is treated. The system equation is reduced to the nonautonomous type of nonlinear differential equation aₖᵢxᵢ+εfₖ(x₁, x₂, ···, x₅, τ) k＝l, 2, ···, 5 ε : small parameter First by means of analog computer the 1/3-harmonic oscillation is investigated and then the extended form of Bogoliubov and Mitropolski's asymptotic method for the system with some-degrees of freedom is used for obtaining the periodic solution

Matric Operational Calculus and Its Applications

In analysing the linear physical systems with many variables, a good method is to use the matrix functions and the operational calculus. This paper describes the fundamental properties of the operational calculus for the matrix functions based on the Mikusinsky's method, and then, presents the method to analyse the periodically excited linear systems (periodically interrupted electric circuits of second genus)