Water conservation and pollution concerns from nutrient runoff will very likely dictate precise irrigation regimes for nursery managers in Virginia. Maximum plant growth with minimum input of water and fertilizer is becoming increasingly important. Therefore, water use and growth of red and sugar maple (Acer rubrum L. 'Franksred' and Acer saccharum Marsh.) were studied during two years of pot-in-pot (P+P) production and during three years after transplanting to field soil. Three major experiments were completed. The first experiment studied the effect of frequent irrigation (three-times-a-day) versus standard once-a-day irrigation and found that frequent irrigation increased trunk diameter growth of sugar maples in the second production cycle and for red maples in both production cycles. Height growth of neither species was affected by frequent irrigation. A study of sap flow pattern indicated that late day water stress of red maples was partially alleviated by frequent irrigation. In the second experiment, red and sugar maples were transplanted to field soil after one (1-yr) or two (2-yr) years of P+P production. Irrigation frequency requirement decreased as the trees grew and depended on environmental conditions, size at planting, source of water (rainfall versus irrigation) and species. Height and trunk diameter of 1-yr red maple was equal to that of 2-yr trees after only one year. Height and trunk diameter differences between 1-yr and 2-yr sugar maple trees persisted three years after transplanting. In the third experiment water use of 1-yr and 2-yr red and sugar maple while in P+P production was investigated. Four models of daily water-use were developed. A simple model that is suitable for growers includes species, trunk cross-sectional area (BA) and air temperature (TA) observations. An environmental model was developed using the Penman-van Bavel estimate of evapotranspiration (ET). ET required modifications based on tree characteristics, air temperature, windspeed and relative humidity to be an effective predictor of water-use. A complex model was based on a sine-cosine function of day-of-the-year. This model fits water-use data well for each species and production cycle and includes BA, ET and TA. An alternate simpler model requires only day-of-the-year, TA and BA, offering growers a relatively simple and accurate model of water use. / Ph. D.

No description available.

The HELMHOLTZ package, written in Maple V, is a collection of commands to support research in the variational calculus. These commands include the standard operators on differential forms, Euler-Lagrange operators, homotopy operators, Lie bracket, Lie derivatives, and the prolongation of a vector field. We give a brief introduction to the variational calculus. We describe each of the commands in the HELMHOLTZ package completely along with numerous examples of each. Applications of the package include verification of symmetry groups for differential equations, solving the inverse problem of the calculus of variations, computing generalized symmetries, and finding variational integrating factors. A complete listing of the Maple code for HELMHOLTZ is found in an appendix.

No description available.

Maple sap was successfully transformed into maple syrup and maple syrup products by evaporation of water by microwave heating. Pulsed power supply with duty cycles of 100%, 75% and 60% were used for the microwave application. The dielectric properties of maple syrup at different moisture contents during the process were determined at 25$ sp circ$C. The products obtained were of excellent quality and were comparable to the highest grade prescribed by the industry. Pulsed power supply was found to have better efficiency of heating, but it increased the total time required for the process. The total time was also found to be dependent on the initial mass of the load. The behavior of the dielectric properties of the maple syrup was found to be fairly linear with moisture content and were found to be in close agreement with an empirical model found in literature. Microwave heating seems to have an enormous potential for production of high quality maple syrup.

This is a broad, quantitative comparison of 12 maple species, representing both canopy and subcanopy growth forms, grown under two ecologically relevant light environments. The maple seedlings responded mainly to light intensity; light quality plays only a minor role in the induction of shade characteristics. While a light-mediated trade off between light and dark reactions of photosynthesis was evident at the chloroplast level, this did not lead to similar differences in assimilaton rates. Gap-grown seedlings showed no apparent compromise in photosynthetic response to dim light and lightflecks. Seedlings of subcanopy trees trade off wood strength for increases in plant size while canopy seedlings sacrifice plant size for wood strength. The demand for greater wood strength in seedlings of canopy trees appears to pose a strong developmental constraint that delays maturation. Free of this constraint, subcanopy species can devote more resource to reach adult size quickly and at an earlier age.

Thesis (Ph. D.)--Drexel University, 2004. / Includes abstract and vita. Includes bibliographical references (leaves 106-116).

Thesis (M.S.)--University of Wisconsin--Madison, 1981. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 157-162).

Thesis (M.S.)--University of Wisconsin--Madison, 1967. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (M.S.)--University of Missouri-Columbia, 2006. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on August 29, 2007) Includes bibliographical references.