Physics Commons^™

Simultaneous Movement Of Water And Herbicides In Unsaturated Soils, Ming-Shyong Yang

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Since weed killers were developed in the early part of the decade beginning in 1940, herbicides have been increasing in use until they are now widely used to control weeds. The application of herbicides has thus become a regular agricultural and ecological practice.

Simultaneous Flow Of Heat And Water In Plant Tissue, Gaylon Sanford Campbell

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Although biological phenomena may be partially described in a general way without the use of mathematics and physics, the experimental results may be more meaningful if they are analyzed on the basis of physical and mathematical laws. The complexity of biological systems has made the application to them of mathematics and physics rather difficult, and only recently has much progress been made. Although it has yet been possible to describe only a few simple biological systems by actual equations, a great deal of qualitative information may be obtained by applying physics and mathematics. Russell (1960, p. 439) said

In principle …

The Influence Of Temperature On The Impedance To Water Flow Through Plants, Royal Duane Jensen

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This era has been termed the atomic or space age. The greatest concern of most people seems to be centered around survival from the destruction and suffering that might be caused by atomic and nuclear weapons. However, along with this, the world is confronted with perhaps a greater disaster--a potential calamity seldom realized by most people, yet a problem which grows more serious in the world each year--a tragedy which would probably be worse than destruction from nuclear weapons. This encroaching catastrophe is starvation.

Even today the majority of the people in the world do not have enough food. Each …

The Freezing Point Of Water In Puddled And Unpuddled Soils At Different Soil Moisture Tension Values, Robert B. Campbell

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A technique that will adequately describe the physical condition of water in the soil has long been desired by scientists. The method should include the effect of soluble materials on the osmotic pressure of the soil solution, and also the effect of surface force action between the soil and soil water.

Parker (8) demonstrated that the freezing point was reduced in the presence of finely divided material. This suggested the possibility of using the cryoscopic procedure to measure the physical condition of water soil. More recently, the introduction of Thermistors for accurate temperature measurement have made it desirable to investigate …