The growing importance of grassland and all its products is becoming more evident. A grassland economy is the backbone of the sheep, dairy cattle, and beef cattle industries. Grassland farming makes for a more permanent type of agriculture. An increased acreage in sod crops results in less erosion, better soil structure and drainage, and higher organic matter. Soil productivity can be maintained or improved under grassland farming practices. A general appreciation of the value of pasture as a source of livestock feed, improvements in strains of grasses and legumes, and better knowledge of fertilizer usage have encouraged the increase in acreage of highly productive pastures. Well managed pastures are highly productive and supply nutritious herbage high in minerals and protein. The Northern Virginia Pasture Research Station at Middleburg, Virginia has experiments under way to measure quantity of production and the nutritional value of pasture herbage when grazed by dairy and beef cattle (1 and 2). These experiments are designed to measure the value of species, mixtures, methods of rotational grazing, and continuous grazing of one mixture as compared with grazing different mixtures in a rotational sequence. Data are being obtained on carrying capacity, livestock gains, carcass characteristics, palatability, and rate of milk production. This study was undertaken to gain supplementary information on the established grazing experiments at Middleburg. It was postulated that data on animal behavior would help interpret the animal responses observed. This report gives data on animal grazing frequency; however, data on other aspects of animal behavior were obtained. / Master of Science

During World War II, with the armed forces waging war on several fronts and with the development of high altitude aircraft, the necessity for a great deal of low temperature testing was brought about. The production testing of various instruments and appliances, such as radios, cameras, clocks, and meters, which would be subjected to low temperatures in arctic climates or at high altitudes, was found necessary. This subject had been given very little consideration prior to the war. When it became necessary to test equipment at a low temperature, it was normally transported to a cold climate and there the tests were conducted. With the increased demand for low temperature testing, the expense and time delay encountered in such movements became prohibitive. During and since the war many low temperature test chambers have been built. The design problems encountered, such as load determination, defrosting, lubrication, refrigerant selection, proper staging, and control selection, have been similar, but the solutions have been different. Moore, Gellalles, and Young state: "Experience has shown that research requirements change so quickly and so radically that the original design specification cannot be much more than a hopeful guess.”(22) Mr. Coy W. Brown states: "Any systems requiring evaporating refrigerant temperatures below -40° F. should be attempted only by engineers experienced in this presently special field."(5) Since definite data on equipment for low temperature test rooms seems to be limited, it is believed that from a design of such a machine much valuable information can be gained. Two low temperature testing rooms have been constructed in the Mechanical Engineering Laboratory at The Virginia Polytechnic Institute. One will operate at temperatures down to 0° F. and the other will operate at temperatures down to -40° F. In addition to being used for low temperature research, it is anticipated that the refrigerating equipment for these rooms will be used by students taking Mechanical Laboratory in routine experiments. The object of this thesis is to design suitable refrigeration equipment for the two rooms. The design will include specifications, bill of material and equipment, detail and assembly drawings, and operating instructions. Available data on the design, control, and operation of low temperature refrigerating equipment will be assembled and correlated. This information, with interpretation thereof, will be used in solving a practical engineering problem which is, at the present, in a special field. / Master of Science

[none] / Master of Science

A series of tests was run to determine the performance characteristics of the 2-1/2 ton steam jet refrigeration unit. The first series of tests was run to determine the nozzle position relative to the throat of the diffuser at which best performance was obtained. This series included tests with two methods of introducing the warm water into the evaporator, namely by spraying the warm water into the evaporator by means of commercial spray nozzles and by spraying the warm water into the evaporator through small holes in a straight piece of pipe. A series of tests was run to determine the effect of the evaporator water level on performance. A series of tests was also run with inlet steam pressures lower and higher than design in combination with outlet pressures at and lower than design. Lastly, one test was run in an effort to reduce the amount of liquid carryover into the ejector. From the results of the above tests the following was concluded: 1. Use of a 62% entrainment efficiency and a 65% diffuser efficiency to give a greater steam flow rate did not enable the design capacity to be met. 2. Best performance of the unit was obtained with the nozzle exit 7-1/2 inches from the entrance to the diffuser throat. 3. Better performance was obtained from the unit by introducing the wara water into the evaporator by means of the commercial spray nozzles than was obtained by introducing the warm water into the evaporator by means of small hole in a straight pipe. 4. Lowering the evaporator water level did not effect performance of the unit greatly. However, control of the unit was greatly enhanced by using a low evaporator water level. 5. Performance of the unit was unstable at inlet steam pressures above design and outlet pressure below design. The capacity of the unit dropped sharply under these condition 6. The design evaporator outlet velocity was too high to enable a sufficiently large amount of liquid carryover to be baffled out. 7. The compression process in the diffuser did not occur as assumed in the design procedure. 8. The throat area of the diffuser should be increased to reduce the fluid velocity in the throat and thereby improve performance of the unit. This is necessary to make the normal shock occur at the throat section of the diffuser. / M.S.

At its inception, it was the purpose of this study to appraise the extent to which democratic methods were being practiced by certain Virginian elementary school administrators as they and their faculties formed, regulated, and implemented school policies and procedures. In order to construct instruments which would measure the extent to which democratic principles were being observed, it was necessary to list some of the specific ways in which administrators and teachers tended to work together. Graduate students and prominent people in the field of elementary education helped to identify those aspects of the administrator-teacher relationship. A city school system in Southside Virginia was selected to provide the background of the investigation, also the school personnel to respond to the research instruments planned for use in this study. Those two instruments, one for elementary teachers and the other for elementary principals, were constructed, again, with the aid of members of the Graduate Seminar at Radford College, and of prominent educators. A search of the literature in the field of elementary administration resulted in the selection of the one criterion used in the study, as follows: A thoroughly democratic administration is needed to insure a successful and happy school. / M.S.

Estimates of feed produced by pasture were obtained from pasture investigations at the Tidewater Field Station from 1949 through 1953, Dry lot groups of pigs similar to those fed on pasture and fed similar rations were used to estimate total concentrates necessary for maintenance and gain of pigs on pasture. Feed production of each pasture was estimated from the difference between concentrates consumed by the pigs on that pasture and total concentrates for similar performance in dry lot. Estimates for 1949 and 1950 were based on the regression of feed consumption on average daily gain of pigs fed in dry lot. Weight of the animals was not considered in computing these estimates, In 1952 and 1953 the regression of feed consumption on weight was the basis for estimates when pigs were fed at the high level of nutrition, end feed required per pound of gain above maintenance for similar weight pigs was the basis for estimates, when pigs were fed at the low level of nutrition. Direct comparisons were made between pigs fed in dry lot and on pasture at the high level of nutrition, since feed consumption and weight were similar, This was not the case with pigs fed in dry lot and on pasture at the low level of nutrition. Feed consumption was the same but average daily gain differed significantly. Since the low level of nutrition provided slight gain for pigs in dry lot, it was necessary that this gain be subtracted from the total gain made by pigs on pasture. The net gain was assumed to be the direct result of the pasture, The feed required per pound of gain above maintenance was calculated and multiplied by the net gain (gain made from pasture), the product being an estimate of the feed replacement value of the pasture lot. Estimations were calculated on a per acre basis. A summary by years of the feed replaced by the pasture is shown in Table 15. This summary indicated that a more consistent estimate was obtained when weight of the animals was included in estimating expected feed consumption, Exceptions to this occurred in 1952 and 1953 when pigs were self-fed on ladino clover. In 1952, the estimated feed replacement value of the pasture, when pigs were provided supplement, was 584 pounds, while in 1953 the estimate was 93 pounds. When supplement was not included in the ration, the feed replaced by the pasture was 26 and 903 pounds for 1952 and 1953, respectively. / Master of Science

The purpose of this investigation was to use the manometric method to determine the effect of the following variables on the B.O.D. values of a neutralized acid industrial waste: pH, type of seed, age of seed, adapted seed, dilution water, and dilution. In order to determine the effect of each variable on the B.O.D. of the waste, the temperature and agitation of the Warburg apparatus were kept at fixed values. While the optimum condition for one variable was being determined, the remaining factors were kept constant. As the optimum condition of each variable was found, it was used as a reaction constant, and this process was continued until the list of variable factors was completed. Since only a limited number of tests were run for each variable, no definite conclusions can be drawn. However, the following trends were indicated from the data obtained: A pH of 4.1 depressed the B.O.D. values and they were exerted only after long lag periods; the waste exerted a higher B.O.D. with much shorter lag periods when the pH was raised to 7.1. River water seed caused the waste to exert higher B.O.D. values than did garden soil seed, fresh sewage seed, and settled sewage seed. This indicated that the river water contained a microbiological population adapted to the utilization of the waste under study. The age of seed made little difference in the B.O.D. values exerted for the seeds studied. The waste gave higher B.O.D. values when adapted seeds of river water, adapted soil seed, end activated sludge were used than when regular garden soil seed was used. It is believed that the bacterial organisms in the river water below the waste outfall had become adapted to the waste material. The presence of mineral nutrients as found in river water or the addition of mineral nutrients as recommended by Standard Methods for the Examination of Water and Sewage (1) are necessary for the waste to exert a normal B.O.D. The presence of a substance toxic to the B.0.D. test is indicated because the B.0.D. values increased with increasing dilution. The bottle B.O.D. values, obtained from another investigator, were not given for all of the tests; therefore, no conclusions were drawn except that the bottle B.O.D. values vere in the same general range as the corresponding manometric B.O.D. values. / Master of Science

The purpose of this investigation was to redesign, construct, and operate a two-inch experimental pulse liquid-liquid extractor, and to determine the effects of the pulse amplitude, the number of plates, and the plate-free-area on the stage efficiency of the column. The optimum liquid flow rates were also determined. An examination of the literature was conducted for a review of the available information on pulse extractors. Although a great deal of literature was available on the topic of liquid-liquid extraction, detailed information on only two pulse extractors could be found. The results obtained during this investigation compare favorably with those reported in the literature. A two-inch experimental pulse-type extractor was constructed. The liquids were pulsed by means of a sylphon-type bellows operated by a push rod which was driven by an eccentric cam. For the satisfactory operation of the extractor various auxiliary apparatus was required; important among these were the supporting framework, the push-rod bearing, the reduction train for the can, the storage tanks, and the tubing and fittings. Twenty-seven individual experimental tests were conducted, extracting acetone from carbon tetrachloride with water, to determine the effects of the various operating parameters on the stage efficiency of the pulse column. During the experimental tests the following variables were studied: pulse amplitude at one, two, and three inches of vertical liquid displacement; number of plates with four, eight, and twelve plates; and plate-free-area with eight, sixteen, and thirty-two per cent free area. It was found that the pulse amplitude, the number of plates, and the plate-free-area each have an independent significant effect on the stage efficiency of the pulse column; the plate-free-area has the largest relative effect, while the pulse amplitude has the smallest relative effect. It was further proven by this investigation that the interactions between the pulse amplitude and number of plates, the pulse amplitude and plate-free-area, and the number of plates and plate-free-area have no significant effect on the stage efficiency of the pulse column. The flow rates for satisfactory column operation are 1807, 2211, 1478, and 2299 pounds per hour-square foot of column cross-section for the feed, solvent, raffinate, and extract, respectively. / Master of Science

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