Forage availability has strong influences on pasture and animal performance. The assessment of herbage yield is an important aim for the management of pastures and animals in systems, concurrently. Four shortcut methods of estimating pasture yield and one method of estimating botanical composition were investigated. The four methods for estimating yields: Visual, Comparative, Yield Index, and Disc, and the Visual estimate of botanical composition, were performed by several estimators on a series of experiments before and after rotational grazing of grass-clover pastures. Visual and Disc methods were also evaluated on experimental plots of ryegrass and bluegrass. Generally, high correlations with actual yield were obtained by all four methods. Correlations with actual clover percentage were very high, being better before than after grazing. The estimators with the highest degree of experience obtained the highest correlations with yields. Experience of estimators had little influence in estimating clover percentage. The Visual method, a very simple and fast technique, consistently gave the higher correlations with yield than other methods. All methods of estimating yield and clover percentages gave reliable estimates. It is concluded that yield estimate techniques should be extensively used in grazing management and other experiments. / Master of Science

A mutation conferring plasmid establishment deficiency in Escherichia coli K-12 strain JF55 has been located on the genetic linkage map. This mutation maps at approximately min 48 and is contransducible with purF. A new use of the process of zygotic induction has been explored to indirectly test the ability of an Est⁻ strain to support the first stage in plasmid establishment. According to zygotic induction evidence employing isogenic strains differing only in the est locus mapped, this mutation influences a stage of plasmid establishment later than the conversion of the single-stranded plasmid DNA to the double-stranded form. In addition, evidence is presented that there is more than one gene influencing plasmid establishment in strain JFSS. One such gene is lon. Other mutations, possibly mapping near his and pyrF may influence the first stage of plasmid establishment in this strain. / Master of Science

Fatigue tests in reversed torsion were run on 2024-T351 aluminum alloy specimens into which hydrogen had been diffused. The diffusion was accomplished by placing the specimens in a hydrogen environment (>99.5%) for 25 days at 2000 psi [13.8 MPa] and 123°C. A control group was tested which underwent the same temperature conditions for 25 days. The fatigue tests were run at low (20-25%) and high (85-90%) relative humidities and at shear stress levels of approximately 13400, 16800, and 20100 psi [89.6, 117, and 138 MPa]. The results of this investigation show that hydrogen charging has no effect on the torsional fatigue life of aluminum. However, a change in the crack propagation angle at high relative humidity for a ductile, circumferential crack on uncharged specimens to a brittle, 45° crack on hydrogen-charged specimens may be the result of hydrogen embrittlement. / Master of Science

Research was conducted to determine relationships among nutrients in corn plants on soils with high yield potentials, to study the suitability of soil tests for estimation of micronutrient concentrations in plants, and to determine if B fertilization affects corn grain yields on selected Virginia soils. Fifty-three field sites were selected in 15 counties throughout Virginia for evaluation of nutrient interactions in plant tissue and micronutrient soil tests. The majority of the soils under study had high yield potentials as attested by the average corn grain yield of 8743 kg/ha. Boron application did not increase corn grain yield in field experiments on five soils. Concentrations of B, Ca, Cu, Fe, K, Mg, Mn, N, P, S, and Zn in the earleaf at the early silk growth stage were determined to assess the nutrient status of corn plants. The experimental data indicated that nutrient concentrations were too low to provide adequate amounts to corn plants on many sites. Corn plants on all of the sites were below the reported critical level of 0.26% S in the earleaf at the early silk growth stage. It was concluded that this critical level may be too high for S deficiency symptoms of corn plants. The negative relationship between concentrations of Ca and K in whole corn plants was attributed to high plant available K in soil which decreases Ca uptake by corn plants. A positive correlation between N and Zn in the sixth leaf tissue was attributed to higher Zn availability as N fertilization decreased soil pH levels. High amounts of soil P which had low soil Zn levels probably caused the inverse relationship between P and Zn in the sixth leaf tissue. Increases in availability of both Cu and Fe at lower pH levels may be responsible for the positive correlation between these micronutrients in the earleaf tissue. Multiple correlation analyses completed between ppm Mn in tissue and dilute HCl-H₂SO₄ extractable soil Mn, pH and organic matter content indicated coefficients of determinations of 0.993 and 0.990 for the 0-20.3- and 0-40.6-cm soil depths, respectively. These data suggest that the Mn test may be a good indicator of available soil Mn to corn plants. Hot water soluble B, soil pH and organic matter content did not give a good indication of B concentrations in corn plants. Extractable Zn by the EDTA-(NH₄)₂CO₃ procedure, soil pH and organic matter content accounted for 84.1% of the variation in Zn concentration in the earleaf of plants at the early silking stage. / Master of Science

This narrative is an attempt to record the service of the 43rd Battalion, Virginia Partisan Rangers, C. S. A. Initially, the unit was composed of nine volunteers from Gen. J. E. B. Stuart's 1st Regiment Virginia Cavalry. By March, 1863, Mosby's rangers had won the hearts of the Confederacy in the daring capture of Union Brig. Gen. E. H. Stoughton. During June, 1863, the first of eight companies was formally organized under the authority of the Partisan Ranger Law. In the ensuing months, the unit concentrated their operations in the Loudoun and Fauquier county areas of northern Virginia. By 1864, the term "Mosby's Confederacy" connotated the influence and span of control tendered by the partisan chief and his command. Federal troops characterized the partisans as "guerrillas'' and "bushwhackers." Mosoy did not disdain the term "guerrilla,” although he defended the ambush tactic. The Partisan Ranger Law authorized plunder as the spoils of war. The battalion had no formal camp. Rangers boarded in the homes of Southern sympathizers or in crude lean-tos. They performed scout and reconnaissance duties in the enemy's rear. Mosby's men harassed the Federal lines of communication and supply, thereby diverting Union reinforcements from the front lines. John S. Mosby was methodical, taciturn, decisive and efficient. Typically, the rangers were twenty-three-year-old farmers who revered their leader and befuddled the enemy. / Master of Arts

The need to conserve the limited natural uranium resources necessitates the determination of the optimal use of M0X fueled reactors under various reactor growth scenarios. The reactor growth scenarios include an industry that attains 400, 507, and 600 operating reactors by the year 2000. The reactor-fuel types under consideration include a PWR and a BWR, each of which can utilize an all U0₂ core, a self-generating recycle core, or a plutonium burner core. Results from developing, analyzing, and solving the reactor mix model are used to recommend specific fuel loading strategies. The reactor mix problem involves the interaction between reactor fuel demand and the availability of SWU, fuel fabrication (U0₂ and M0X), reprocessing, and spent fuel generation. The cost of each type of nuclear fuel is based upon projected costs of uranium, separative work, conversion, reprocessing, and fuel fabrication, as well as plutonium and spent uranium values. Application of the reactor mix model is done on an annual basis for a twenty-five year planning horizon. The model application is developed through a linear program. The analyses of the linear program problem is done by the use of the proprietary mathematical MPS-III system. Specific results indicate that spent uranium and plutonium should be utilized in self-generating reactors in order to minimize the consumption of the natural uranium resources. The ability to reprocess spent fuel and to fabricate M0X fuel assemblies are the parameters which restrict the effective introduction of these reactors. / Master of Science

The study was designed to ascertain the knowledge, opinions, and behaviors concerning consumer rights and responsibilities of the potential community consumer education leaders attending a state-wide leadership conference. A variety of community leaders frcxn paraprofessional volunteers to professionals from various fields were present. Usable data were collected from 201 conference participants; this represented 63.61% of those in attendance. The "Measurement of Consumer Rights and Responsibilities" (MCRR) was developed which included twenty-six multiple-choice questions to measure knowledge, twenty-six statements with a six-point Likert-type scale to assess opinions, and seven behavior questions related to consumer responsibilities. Mean achievement score on the knowledge section was 19.14, representing 73.62% correct. Kuder-Richardson formula twenty reliability estimate equaled 0.52. Item analysis indicated positive point biserial correlations for all questions. The opinions expressed indicated that the respondents generally were aware of their consumer rights and responsibilities, firmly agreed with them, and responded in the direction anticipated of actively responsible consumers. In several instances the most intense level of agreement or disagreement was expressed. Reported behaviors indicated that the majority of the respondents accepted the responsibility to express their consumer voice by refusing to buy products, taking action against poor quality products, using product information to aid decision making, and by demonstrating generally ethical marketplace behavior. Most (88.06%) failed to accept the responsibility to affiliate with a local or state-wide consumer action group. No statistically significant relationship existed among the knowledge, opinions, and behaviors reported by the potential community consumer education leaders concerning consumer rights and responsibilities. Sex, education, age and income of the respondents were not related to the opinions and behaviors reported. A significant relationship existed between the knowledge of consumer rights and responsibilities and the sex, education, and income of the respondents. The males scored significantly higher than the females on the knowledge section. Those with more education scored better than those with less education, while the potential consumer leaders with higher incomes scored better than those with lower incomes. / Master of Science

Nine .16 ha study areas were established in Appalachian oak forests on Potts Mountain in Craig County, Virginia to assess vegetation structure and its relationship to differences in site. A number of structural parameters were measured by height strata to determine vertical stratification patterns. Foliage density was used in subordinate strata (< 5.0 m) as a comparative measure of vegetative structure. The results indicate that the contribution of shrubs to vegetation structure is much higher on xeric than mesic sites, while trees are of greater significance on mesic sites. This suggests a proportionally higher utilization of site resources by subordinate strata on xeric sites. A cluster analysis of the study areas based on several structural parameters indicated that differences in stand structure may be associated with differences in available moisture. Foliage density in subordinate strata appeared to have some value as an integrator of vegetative structure on the study areas. / Master of Science

A study was conducted to determine the importance of algae as sources of orgnanic precursors in the haloform reaction. Two species each of green and blue-green algae were grown in laboratory conditions and harvested periodically during their growth cycle. The principal part of the study was directed toward determining the patterns of extracellular products excretion into the medium and of the chloroform produced after chlorination. Similar studies of cell suspensions were conducted. The study also included an analysis of the chloroform yields from chlorinated reservoir sediments and pure compounds known to be algal extracellular metabolites. The results indicated that the extracellular products of growing algal cells have the greatest potential as haloform precursors and that the greatest excretion of high chloroform-yielding compounds generally occurred during exponential growth. The blue-green algae were found to liberate more organic carbon than the green algae and produced higher chloroform concentrations upon chlorination. However, the green algae generally showed excretion of higher chloroform-yield compounds. The chloroform yields per unit organic carbon for the algal extracellular products often exceeded those reported for the humic substances and, therefore, could be considered of equal or greater importance as haloform precursors under certain conditions. Yields from solutions of pure compounds and from the sediments were significantly lower than those from the extracellular products and biomass of growing algal cells. Increasing the pH of the solutions of pure compounds resulted in higher chloroform yields, a result that has been demonstrated by others. / Master of Science

An experimental study of internal flow separation at high incidence angles for two two-dimensional inlet models is presented. A description of the inlet testing facility includes the injector (which serves to drive the air through the inlet model), its control system, and the Virginia Tech 6-foot subsonic wind tunnel. The geometry of the two inlet models is discussed and the inlet model instrumentation is described. The injector is calibrated in preparation for the inlet model tests and found to exhibit satisfactory performance. Inlet models GE-1 and GE-2 are tested at incidence angles of 0°, 15°, and 30°, and at throat Mach numbers of 0.38, and 0.73. Preliminary data is presented and comparisons show a favorable trend toward delaying internal flow separation for the inlet model which has a thicker lip (higher contraction ratio). / Master of Science