Heat Capacity Effects Associated with the Hydrophobic Hydration and Interaction of Simple Solutes: A Detailed Structural and Energetical Analysis Based on MD Simulations

We examine the SPCE and TIP5P water models to study heat capacity effects associated with the hydrophobic hydration and interaction of Xenon particles. We calculate the excess chemical potential for Xenon employing the Widom particle insertion technique. The solvation enthalpy and excess heat capacity is obtained from the temperature dependence of the chemical potentials and, alternatively, directly by Ewald summation, as well as a reaction field based method. All three different approaches provide consistent results. The reaction field method allows a separation of the individual components to the heat capacity of solvation into solute/solvent and solvent/solvent parts, revealing the solvent/solvent part as the dominating contribution. A detailed spacial analysis of the heat capacity of the water molecules around a pair of Xenon particles at different separations reveals that the enhanced heat capacity of the water molecules in the bisector plane between two Xenon atoms is responsible for the maximum of the heat capacity observed at the desolvation barrier, recently reported by Shimizu and Chan ({\em J. Am. Chem. Soc.},{\bf 123}, 2083--2084 (2001)). The about 60% enlarged heat capacity of water in the concave part of the joint Xenon-Xenon hydration shell is the result of a counterplay of strengthened hydrogen bonds and an enhanced breaking of hydrogen bonds with increasing temperature. Differences between the two models concerning the heat capacity in the Xenon-Xenon contact state are attributed to the different water model bulk heat capacities, and to the different spacial extension of the structure effect introduced by the hydrophobic particles. Similarities between the different states of water in the joint Xenon-Xenon hydration shell and the properties of stretched water are discussed.Comment: 14 pages, 16 figures, twocolumn revte

Gauge Theory of Gravity Requires Massive Torsion Field

One of the greatest unsolved issues of the physics of this century is to find a quantum field theory of gravity. According to a vast amount of literature unification of quantum field theory and gravitation requires a gauge theory of gravity which includes torsion and an associated spin field. Various models including either massive or massless torsion fields have been suggested. We present arguments for a massive torsion field, where the probable rest mass of the corresponding spin three gauge boson is the Planck mass.Comment: 3 pages, Revte

Bounded phase coordinate control second quarterly progress report, 15 sep. - 14 dec. 1964

Approximation to linear bounded phase coordinate control problem

Projective measurement in nuclear magnetic resonance

It is demonstrated that nuclear magnetic resonance experiments using pseudopure spin states can give possible outcomes of projective quantum measurement and probabilities of such outcomes. The physical system is a cluster of six dipolar-coupled nuclear spins of benzene in a liquid-crystalline matrix. For this system with the maximum total spin S=3, the results of measuring $S_X$ are presented for the cases when the state of the system is one of the eigenstates of $S_Z$.Comment: 9 pages incluing 3 figure

Manufacturing Mechatronics Using Thermal Spray Shape Deposition

A new technology for manufacturing mechatronics is described. The technique is based on recursive masking and deposition of thermally sprayed materials. Using these methods, mechanical structures can be created that embed and interconnect electronic components. This results in highly integrated mechatronic devices. A simple, electromechanical artifact was designed and produced to assess the feasibility of these techniques. The details and limitations of this project will be discussed. Areas of future research are identified which are aimed at realizing the full potential of this emerging manufacturing process.Mechanical Engineerin

Primitive model electrolytes. A comparison of the HNC approximation for the activity coefficient with Monte Carlo data

Accuracy of the mean activity coefficient expression (Hansen-Vieillefosse-Belloni equation), valid within the hypernetted chain (HNC) approximation, was tested in a wide concentration range against new Monte Carlo (MC) data for +1:-1 and +2:-2 primitive model electrolytes. The expression has an advantage that the excess chemical potential can be obtained directly, without invoking the time consuming Gibbs-Duhem calculation. We found the HNC results for the mean activity coefficient to be in good agreement with the machine calculations performed for the same model. In addition, the thermodynamic consistency of the HNC approximation was tested. The mean activity coefficients, calculated via the Gibbs-Duhem equation, seem to follow the MC data slightly better than the Hansen-Vieillefosse-Belloni expression. For completeness of the calculation, the HNC excess internal energies and osmotic coefficients are also presented. These results are compared with the calculations based on other theories commonly used to describe electrolyte solutions, such as the mean spherical approximation, Pitzer's extension of the Debye-H\"uckel theory, and the Debye-H\"uckel limiting law.Comment: 15 pages, 6 figure

Branching process approach for Boolean bipartite networks of metabolic reactions

The branching process (BP) approach has been successful in explaining the avalanche dynamics in complex networks. However, its applications are mainly focused on unipartite networks, in which all nodes are of the same type. Here, motivated by a need to understand avalanche dynamics in metabolic networks, we extend the BP approach to a particular bipartite network composed of Boolean AND and OR logic gates. We reduce the bipartite network into a unipartite network by integrating out OR gates, and obtain the effective branching ratio for the remaining AND gates. Then the standard BP approach is applied to the reduced network, and the avalanche size distribution is obtained. We test the BP results with simulations on the model networks and two microbial metabolic networks, demonstrating the usefulness of the BP approach

Relationships among Prices across Alternative Marketing Arrangements for Fed Cattle and Hogs

Reduced reliance on cash market prices for fed cattle and hogs raise questions about the role of cash prices in price discovery. We use seven years of weekly data from mandatory price reports to determine whether or not cash market prices are cointegrated with other procurement prices and then test for causality among the price series. Cash prices were cointegrated with all but one procurement price series. Cash market prices Granger cause all other procurement prices. Bidirectional causality was found in some but not all cases. Thus, cash market prices remain of central importance in price discovery for fed cattle and hogs.cattle, cointegration, causality, hogs, Johansen, marketing, prices, Stock-Watson, vector error correction, Livestock Production/Industries, Marketing, Q13(of Q18),