In conventional methods of aquifer tests, homogeneous and isotropic formations are assumed. In many instances, however, aquifers are anisotropic. To resolve this problem, three‐dimensional flow equations in homogeneous, anisotropic and leaky aquifers are derived. With the equation and method outlined in the report, we can determine the three components of directional permeability (x, y, and z) in the presence of leakage, and determine the statistical distribution of fractures and stream channels. Field tests that verify our theory are presented.

Pitting, as the term is used in this paper, means a form of failure which occurs on gear teeth near the pitch circle, on rollers, in anti-friction bearings, and on other machine parts where cylindrical surfaces come in rolling contact under heavy loads. The purpose of the investigation described in this paper is to study the manner in which pits develop, to discover the reason for their development, and to find what conditions must be fulfilled to prevent their occurrence. A testing machine was used in which steel rollers approximately 1.5 in. in diameter, rolling together and loaded as shown in Fig. 2, could be tested. More than eighty tests have been made with rollers of different materials, with different lubricants, and with various loads. Pits are found to have a definitely characteristic shape and orientation with respect to the direction of rolling. They were observed to develop from minute cracks in the roller surfaces which appear after about 500,000 revolutions. Photographs were taken tracing the growth of these pitting cracks from their earliest observed stage. The cracks from the very beginning have a characteristic shape and orientation. The principal findings in the tests on the steel rollers were: (1) That a lubricant must be present if pitting is to take place; (2) that if the lubricant is of a viscosity above a certain critical value which depends on the load, pitting can be prevented; (3) that the nature of the surface finish on the rollers greatly influences the tendency to pit, pitting being prevented on a highly polished surface and accelerated on a rough-machined surface; (4) that nitrided rollers will not pit under conditions that would result in severe pitting of quenched and tempered mild carbon-steel rollers, also that pits are smaller on harder surfaces, in general. In the theoretical section of the paper, the load-carrying capacity for the oil film between two rollers having a common peripheral velocity is calculated, and it is shown that the critical viscosity necessary to prevent pitting is far below that necessary to prevent metal-to-metal contact, a fact also checked experimentally. The normal and tangential oil forces on the rollers after metal-to-metal contact are also calculated, and the tangential component is found to be small compared with the normal component. Calculation showed that no tensile stress would exist at the surface, where pitting cracks appear to start, due to contact pressure or oil forces. However, it is found by analysis that a small crack in the surface, if filled with oil, will tend to grow, provided it has a certain initial direction. This direction is the same as that of the cracks which precede pitting. This strongly suggests that oil penetration of very small surface cracks with a certain initial direction is the reason for the growth of these cracks until a particle is separated from the main body of material, leaving a pit. The experimental results harmonize, also, with this theory.

This paper is a report on the development of an experimental MHD electrical generator which derives its energy from the combustion of a liquid fuel and oxygen. The fuel burned is a number 2 distillate oil in which a soluble potassium octoate is mixed to increase the degree of thermal ionization in the product gas. The actual generating volume is approximately 125 cubic inches and the rating of 10 KW has been exceeded. The paper describes some of the broad construction features of the generator and problems arising during its operation. Other sections deal with the fuel and combustion systems, fuel characteristics, and the electrical and magnetic aspects. The theory of MHD power generation in a uniform duct is presented. Results of the experiments are presented and actual performance compared with theory. The paper is illustrated with photographs and sketches of the various components and curves of power and voltage.

This paper discusses the relative merits of various fuels for magnetohydrodynamic power systems in which the MHD generator operates on combustion products and is coupled with a steam plant or gas turbine. The method of calculating the equilibrium gas composition is first discussed, and results are then given for alkali seeded product gas compositions and properties for cases of bituminous coal, coke, natural gas, residual oil, and alcohol. Electrical conductivity, electron mobility, and attainable flame temperatures are evaluated. Fuels of low hydrogen content are shown to be advantageous, and it is shown to be desirable to introduce the alkali seed in a dry state.

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