PEO/CHCl3: Crystallinity of the polymer and vapor pressure of the solvent - Equilibrium and non-equilibrium phenomena -

Vapor pressures were measured for the system chloroform/polyethylene oxide (peo, weight average molar mass = 1000 kg/mol) at 25 degrees centigrade as a function of the weight fraction w of the polymer by means of a combination of head space sampling and gas chromatography. The establishment of thermodynamic equilibria was assisted by employing thin polymer films. The degrees of crystallinity alpha of the pure peo and of the solid polymer contained in the mixtures were determined via dsc. An analogous degree of polymer insolubility, beta, was calculated from the vapor pressures measured in this composition range. The experiments demonstrate that both quantities and their concentration dependence are markedly affected by the particular mode of film preparation. These non-equilibrium phenomena are discussed in terms of frozen local and temporal equilibria, where differences between alpha and beta are attributed to the occlusion of amorphous material within crystalline domains. Equilibrium information was obtained from two sources, namely from the vapor pressures in the absence of crystalline material (gas/liquid) and from the saturation concentration of peo (liquid/solid). The thermodynamic consistency of these data is demonstrated using a new approach that enables the modeling of composition dependent interaction parameters by means of two adjustable parameters only

The antigenic index: a novel algorithm for predicting antigenic determinants

In this paper, we introduce a computer algorithm which can be used to predict the topological features of a protein directly from its primary amino acid sequence. The computer program generates values for surface accessibility parameters and combines these values with those obtained for regional backbone flexibility and predicted secondary structure. The output of this algorithm, the antigenic index, is used to create a linear surface contour profile of the protein. Because most, if not all, antigenic sites are located within surface exposed regions of a protein, the program offers a reliable means of predicting potential antigenic determinants. We have tested the ability of this program to generate accurate surface contour profiles and predict antigenic sites from the linear amino acid sequences of well-characterized proteins and found a strong correlation between the predictions of the antigenic index and known structural and biological data

ECONOMICS OF HEIFER RAISING OPTIONS

As dairy farms grow and specialize in milking cows, one enterprise that may be removed from the dairy farm to allow for milk cow herd expansion is heifer raising. Custom heifer raising is increasingly common across the country and purchasing heifers may be preferred to raising heifers. However, these alternatives are not suitable for all dairy farmers. In this article, we examine heifer enterprise costs relative to using a custom raiser or purchasing heifers. We identify factors that should be considered in making the proper decision relative to the heifer enterprise.Livestock Production/Industries,

DAIRY FARM DECISIONS ON HOW TO PROCEED IN THE FACE OF TB

By early 2000, the number of commercial livestock herds in Michigan with bovine tuberculosis (TB) had increased to the point that policy makers were considering alternative ways to enable farmers to continue production with access to markets while eliminating TB and protecting the public's health. If at least one animal on a farm is found to have TB, a farmer currently has two choices about the future assuming the goal is to stay in the livestock business. Alternative one is depopulation; all animals are removed to a state facility, slaughtered, and tested. A new herd may be purchased after a state supervised clean up and waiting period is completed; this may take one year. Alternative two is test and remove; a recurring series of testing is initiated, but only individual reactor or suspect animals are removed for slaughter and further testing. In both alternatives, regulations allow indemnity payments to be made to the owner by the state and federal governments. This paper analyzes the financial impact of each alternative on two dairy benchmark farms. One has 75 milk cows, the other 150. Monthly cash flow projections for two years were made using FINFLO. A base projection was compared to the above alternatives assuming constant herd size (except for the impact of TB) and constant price levels. The main goal was to illustrate how a farmer might analyze the alternatives if faced with TB infected animals. The 75 cow farm started with $8,309 of cash on January 1, 2000. The base projections resulted in cash of$34,230 by December 31, 2001. Ending cash after two years for depopulation or test and remove were $16,095 and$15,801, respectively. The 75 cow farm started with a net worth of $624,940 on January 1, 2000. The base projection increased net worth by$66,542 over the two years. For depopulation or test and remove, the change in net worth by the end of 2001 was $-15,345 and$48,256, respectively. The 150 cow farm started with $30,659 of cash on January 1, 2000. The base projections resulted in cash of$40,437 by December 31, 2001. Ending cash after two years for depopulation or test and remove were $2,972 and$13,290, respectively. The 150 cow farm started with a net worth of $1,122,940 on January 1, 2000. The base projection increased net worth by$31,765 over the two years. For depopulation or test and remove, the change in net worth by the end of 2001 was $-95,904 and$-1,925, respectively. Benchmark model farms will not exactly fit any particular farm. Each owner faced with TB should make their own projections using their unique situation and timing of cash flows. Once an alternative is adopted, monthly financial comparison sheets can be helpful in managing the transition to TB free status.Livestock Production/Industries,

Kaon production and propagation at intermediate relativistic energies

We systematically study $K^+$ observables in nucleus-nucleus collisions at 1-2 A GeV within the Boltzmann-Uehling-Uhlenbeck (BUU) transport model. We compare our calculations with the KaoS data on the kaon multiplicities and spectra. In addition, the kaon collective flow is computed and compared with the FOPI and KaoS data. We show, that the elliptic kaon flow measured recently by the KaoS Collaboration is best described by using the Brown-Rho parametrization of the kaon potential ($U_K(\rho_0) \simeq 30$ MeV).Comment: 21 pages, 3 tables, 17 figures; references added; version accepted in PR

Magnetic shielding and vacuum test for passive hydrogen masers

Vibration tests on high permeability magnetic shields used in the SAO-NRL Advanced Development Model (ADM) hydrogen maser were made. Magnetic shielding factors were measured before and after vibration. Preliminary results indicate considerable (25%) degradation. Test results on the NRL designed vacuum pumping station for the ADM hydrogen maser are also discussed. This system employs sintered zirconium carbon getter pumps to pump hydrogen plus small ion pumps to pump the inert gases. In situ activation tests and pumping characteristics indicate that the system can meet design specifications

USING A MULTIPLE PRODUCT AND MULTIPLE INPUT APPROACH TO DAIRY PROFIT MAXIMIZATION: A SIMULATION USING OPERATIONS RESEARCH METHODS

Dairy producers generally take a single output/multiple input approach when making production decisions. Under component pricing, with large variance in individual component prices, a multiple output/multiple input approach maximizes profits. This paper applied our approach to the individual farm milk production decision.Livestock Production/Industries, Productivity Analysis,

PROFITABILITY AND PRODUCTION EFFICIENCY OF THE CROP AND LIVESTOCK ENTERPRISES OF MICHIGAN DAIRY OPERATIONS: 1998 SUMMARY AND ANALYSIS

This paper summarizes the 1998 results of the Dairy Profitability and Production Efficiency project. Among the major findings are that the average cost of production was almost exactly equal to the average milk herd revenue on a per hundredweight basis. All eight farms covered variable costs of producing milk. Five of the eight farms showed a profit when all costs of production were included. All six farms that raised their own replacement heifers lost money on the enterprise. With respect to crop production, corn and corn silage were not profitable enterprises. The hay enterprise was profitable for five of the farms.Productivity Analysis,