Physical Sciences and Mathematics Commons^™

Mechanism Of Water Transport Through Reverse Osmotic Membranes, Cheryl Kay Murphy

Theses and Dissertations

Cellulose acetate membranes show a higher permeability to water than to salt and are being used for desalination of salt water by reverse osmosis. Use of highly acetylated cellulose membranes give a higher salt rejection but also decrease flow rate of the water. The addition of very-short-chain substances or alkyl groups larger than one carbon atom to the cellulose membrane also decreases water flux. A proposed mechanism of transport through the membrane is that the water molecule is passed along the chain by hydrogen bonding with the acetyl groups, The NMR shows a change in the chemical shift of water …

Salinity And Water Potential Sensor For Evaluation Of Soil Water Quality, Melvin Dee Campbell

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The objective of this study was to evaluate response times of a salinity sensor and a soil psychrometer. Influences of pressure, temperature and molar concentration changes were to be measured.

Salinity sensor response times ranged from 50 to 130 minutes during solution adsorption while desorption response times were perhaps ten times as long. Temperature affected both response times and equilibrium values, but pressure did not affect either.

Soil psychrometer response times ranged from from 40 to 80 minutes for either adsorption or desorption of solution. However, other factors probably related to indirectness of measurement made the soil psychrometer fail to …

Ground Water Atlas Of Nebraska (June 1969), V. H. Dreeszen, J. A. Elder, E. C. Weakly, E. C. Reed, G. R. Svoboda

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

Nebraska's Water Supply Map Including Groundwater In Storage, Total Water Withdrawals, Precipitation, And Outflow As Of 1969

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

The Influence Of Thermo-Gradients Upon Water Movement And Retention In Unsaturated Soils, Jose V. Salazar

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Temperature differences of about 5, 10, and 15 V, were applied to uniformly packed and insulated horizontal column of Millville silt loam soil using mean temperatures near 13, 14, 15, 16, 17, 18, 19, 20 and 23.5 C. The temperature distribution along the soil column was determined using copper constantan thermocouples. Soil samples were taken to determine volumetric moisture content, and soil water potential, using the vapor pressure psychometer technique. The thermodynamic flow equation of Taylor and Cary, (1964) was used to calculate the hydro-thermal transfer coefficient (ß) as given by:

-ß = d(μ_w)_T / dlnT

where …

The Influence Of Soil Moisture Regimes And Atmospheric Environments On Transpiration And The Energy Status Of Water In Plants, Sampatrao A. Gavande

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Plant responses to different soil moisture regimes have been extensively studied. Because of interactions between the soil, plant and climatic factors, few convincing generalizations concerning the influence of soil water on the transpiration of water by plants have been established. Generally single factors or at most the interaction of two have been studied at any one time. Useful theories describing the conditions of water retention in plant tissues and movement of water through plants have been proposed. Equally useful theories have been suggested for describing the retention and transmission of water in soil. The integration of these theories and their …

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 Interaction Of Water And Salt Flow In Unsaturated Soils, Mahmoud Hassan Abd-El Aziz

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The movements of salt and water, particularly in fairly dry soils or compacted shales, are important processes in both agronomic studies and hydraulics of deep ground water which is important in the location of oil.

Irrigation: Soil-Plant-Water Relationships, Soil Conservation Service, Engineering Division

All U.S. Government Documents (Utah Regional Depository)

Soil-Plant-Water relationships describes those properties of soils and plants that affect the movement, retention, and use of water essential to plant growth. This publication attempts to provide engineers the basic data necessary to plan and maintain efficient conservation irrigation practices to provide a permanent irrigated agriculture engineering principles and research findings have been screened to give emphasis to the information needed to design, install, and operate irrigation systems on farms or groups of farms.

Pressure Dependence Of Soil Water Matric Potential, Bozorg Bahrani

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The partial specific Gibbs¹ free energy or the chemical potential has been shown to be the most desirable thermodynamic function for describing soil-water systems. The absolute value of the chemical potential of soil water cannot be determined. If pure water at standard temperature and pressure is taken as the reference, the difference between the chemical potential of soil water and that of the reference can be measured and is called "soil water potential," which has the dimension of energy per unit mass.

The barometric pressure at the sea level has been accepted as the standard reference pressure. Thus, any …

Salt Effect On Water Requirements Of Plants, Abdel-Wahhab M. H. Sallam

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Water requirement was defined by Briggs and Shantz in 1911 as the ratio of the weight of water absorbed by a plant during its growth to the weight of dry matter produced. Ballard (1933) and Williams (1935) defined water requirement as the ratio of the amount of water transpired to the amount of dry matter produced. Ballard (1933) and Williams (1935) defined water requirement as the ratio of the amount of water transpired to the amount of dry matter formed during the whole or any part of the life cycle of the plant. Miller (1938) and Kramer (1959) postulated that …

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 …

Water For Man, Sterling A. Taylor

Faculty Honor Lectures

Man's uses for water are rapidly increasing. His demands and needs for water for his personal use and for cleanliness, recreation, industry, and food production are increasing as the population and standard of living rise. At the same time, his knowledge of the behavior and nature of water is increasing.

An Application Of A Thermodynamic Flow Equation To Water Movement In Unsaturated Soil, Brennan Derry Soane

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The movement of water in soil presents many interesting problems to the research worker. It is also a subject which finds wide and important application in agriculture and several branches of engineering.

The object of this work was to examine the usefulness of a new equation of flow of water in unsaturated soil. If valid, this new approach may be able to eliminate some of the gaps in our present knowledge of the subject.

All soil lying above the capillary fringe of a water table is in the unsaturated state with respect to water. This means that in any macroscopic …

The Peltier Effect And Its Use For Measuring Relative Activity Of Soil Water, Hans C. Korven

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Soil moisture measurement embraces two basic concepts, namely, water content and relative activity. The measurement of moisture content, either on a weight or volume basis, yields the amount or quantity of water in the soil. The measurement of relative activity or the energy required to remove unit of water is related to the availability of the soil moisture to the plant. The measurement of soil bulk density, irrigation efficiency, and the amount of water to apply in an irrigation are a few examples that require the use of the moisture content concept. Whereas the first concept determines the amount of …

Preliminary Estimate Of The Underflow Across The South Dakota-Nebraska State Line In The Niobrara River And Ponca Creek Drainage Basins, E. C. Reed, C. F. Keech

Conservation and Survey Division: Faculty and Staff Publications

The purpose of this paper is to estimate the amount of ground water flowing across the South Dakota-Nebraska State line within the Niobrara River basin, including the Ponca Creek basin. The study was made at the request of the Niobrara River Compact Commission. The estimates fiven in the paper are preliminary and subject to revision.

Great Salt Lake Diking Project, Large Plan, Hydrology And Quality Of Water Study, United States Department Of Interior, Bureau Of Reclamation

Elusive Documents

The purpose of this study was to determine the feasibility of diking a portion of the Great Salt Lake for purposes of using the fresh water for irrigation, industrial uses, and recreation. This study approached the problem only for a hydrologic and quality of water standpoint.

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 …

The Integration Of Water Use In Nebraska, G. E. Condra

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

Land And Water Conservation Problems Of The Missouri River Basin, G. E. Condra

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

Terminology Relating To The Occurrence, Behavior And Use Of Water In Nebraska, G. E. Condra

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

Water Resources Of Nebraska

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

A Study Of The Equilibria Between Bentonite And The Various Replacing Agents In Alcoholic And Water Solutions, Joel E. Fletcher

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Investigators in soils have long recognized the importance of the colloidal fraction of soil, and also the almost inseparable problem of replaceable bases. It is generally accepted that the replaceable base fraction of a colloid controls to a large degree the physical properties exhibited by it. Volumes of work have been written on the problem of controlling the reactions of this fraction and on studies of the properties exhibited by it when it is saturated with various cations. Each worker has proceeded in his own individual way or followed the example set by some previous worker with specific modifications.

Conservation Of Land And Water Resources Of Nebraska, G. E. Condra

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

Water-Bearing Formations Of Nebraska, G. E. Condra, E. C. Reed

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

Water, W. J. Mayo

Journal of the Minnesota Academy of Science

In the hope of stimulating interest in the problem of water, I wish to devote a few minutes to some of the physical properties of water.

Lincoln's Water Supply Problem

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

Bulletin 115 - The Value Of Windmills For Pumping Water In Western Australia, A. H. Scott

Bulletins 1 - 2999

It is surprising to note the dearth of up-to-date reliable information dealing with actual results of modern windmills, under working conditions, though literature on thousands of other subjects less important can usually be obtained.

In this bulletin there is presented a complete and accurate record of the amount of water pumped daily by a windmill, under actual working conditions, for a period of 14 months.

Drainage Districts Of Southeastern Nebraska, Calvin Turner Moore

Conservation and Survey Division: Faculty and Staff Publications

Throughout certain parts of the United States the importance of drainage is receiving increased recognition each year. The scope of investigations and operations covers many localities that are affected with "springy" lands, swamps, shallow lakes, overflowed lands, and tide lands.