Ultrasound instrumentation for the 7 inch Mach seven tunnel

The use of an Apple II+ microcomputer to collect data during the operation of the 7 inch Mach Seven Tunnel is discussed. A method by which the contamination of liquid oxygen is monitored with sound speed techniques is investigated. The electrical equivalent of a transducer bonded to a high pressure fill plug is studied. The three areas are briefly explained and data gathered for each area are presented

Quantum spin Hall effect and spin-charge separation in a kagome lattice

A two-dimensional kagome lattice is theoretically investigated within a simple tight-binding model, which includes the nearest neighbor hopping term and the intrinsic spin-orbit interaction between the next nearest neighbors. By using the topological winding properties of the spin-edge states on the complex-energy Riemann surface, the spin Hall conductance is obtained to be quantized as $-e/2\pi$ ($e/2\pi$) in insulating phases. This result keeps consistent with the numerical linear-response calculation and the \textbf{Z}$_{2}$ topological invariance analysis. When the sample boundaries are connected in twist, by which two defects with $\pi$ flux are introduced, we obtain the spin-charge separated solitons at 1/3 (or 2/3) filling.Comment: 13 NJP pages, 7 figure

Optical excitations in hexagonal nanonetwork materials

Optical excitations in hexagonal nanonetwork materials, for example, Boron-Nitride (BN) sheets and nanotubes, are investigated theoretically. The bonding of BN systems is positively polarized at the B site, and is negatively polarized at the N site. There is a permanent electric dipole moment along the BN bond, whose direction is from the B site to the N site. When the exciton hopping integral is restricted to the nearest neighbors, the flat band of the exciton appears at the lowest energy. The higher optical excitations have excitation bands similar to the electronic bands of graphene planes and carbon nanotubes. The symmetry of the flat exciton band is optically forbidden, indicating that the excitons related to this band will show quite long lifetime which will cause strong luminescence properties.Comment: 4 pages; 3 figures; proceedings of "XVIth International Winterschool on Electronic Properties of Novel Materials (IWEPNM2002)

Heat-Treated Soybean Proteins for Lactating Dairy Cattle

The value of heat treatment of protein supplements to reduce protein solubility and increase protein utilization was studied in two lactation trials. Experiment I was designed to study the utilization of heat-treated soybean meal (HSBM) by cows in early lactation. An extrusion process with moist heat was used to produce HSBM - a product with lower protein solubility than regular soybean meal (SBM). Ten cows, 3 wks post-partum, were assigned to treatments of HSBM or SBM. Due to a problem in feed bag labeling the concentrate mix containing SBM and corn was not as formulated. A large amount of ground whole soybeans was substituted for SBM making the concentrate mix lower in protein and higher in fat than intended. Milk production was higher for the cows fed HSBM due to either the higher amount of protein that they received and/or the lower protein solubility of that diet. No change was seen in milk fat percent, protein, protein components or total solids. Experiment II used a switchback design with 12 cows to determine the feeding value of a heat treated soybean product. Treatments were commercially available heat-treated soybeans (HTP), the unheated ingredients of HTP (HTP-U) and regular soybean meal (SBM). Nitrogen solubility of the protein sources in 10% Burrough\u27s buffer solution was 9.4, 25.4, and 13.8%, respectively. Concentrate mixes of protein sources and corn were formulated to contain 16% crude protein and fed at the rate of 1 kg/3 kg milk. Production of 4% fat-corrected-milk was similar for all treatments, although, production tended to be highest for cows fed heat-treated soybeans. No differences were observed in milk fat percent or total solids. Protein percent of milk was lower when fed HTP and HTP-U probably due to the higher fat content of those diets. Amounts of long chain unsaturated fatty ·acids in milk fat were increased with HTP and HTP-U diets. Rumen ammonia and serum urea were lower when fed HTP and HTP-U. This study indicates that heating soybeans improved their value slightly as a feed for lactating cows, but milk production by cows past peak production was not significantly greater than production achieved with conventional corn-soybean meal diets

Modulation Equations: Stochastic Bifurcation in Large Domains

We consider the stochastic Swift-Hohenberg equation on a large domain near its change of stability. We show that, under the appropriate scaling, its solutions can be approximated by a periodic wave, which is modulated by the solutions to a stochastic Ginzburg-Landau equation. We then proceed to show that this approximation also extends to the invariant measures of these equations

On microscopic origins of generalized gradient structures

Classical gradient systems have a linear relation between rates and driving forces. In generalized gradient systems we allow for arbitrary relations derived from general non-quadratic dissipation potentials. This paper describes two natural origins for these structures. A first microscopic origin of generalized gradient structures is given by the theory of large-deviation principles. While Markovian diffusion processes lead to classical gradient structures, Poissonian jump processes give rise to cosh-type dissipation potentials. A second origin arises via a new form of convergence, that we call EDP-convergence. Even when starting with classical gradient systems, where the dissipation potential is a quadratic functional of the rate, we may obtain a generalized gradient system in the evolutionary $\Gamma$-limit. As examples we treat (i) the limit of a diffusion equation having a thin layer of low diffusivity, which leads to a membrane model, and (ii) the limit of diffusion over a high barrier, which gives a reaction-diffusion system.Comment: Keywords: Generalized gradient structure, gradient system, evolutionary \Gamma-convergence, energy-dissipation principle, variational evolution, relative entropy, large-deviation principl

Effective rate equations for the over-damped motion in fluctuating potentials

We discuss physical and mathematical aspects of the over-damped motion of a Brownian particle in fluctuating potentials. It is shown that such a system can be described quantitatively by fluctuating rates if the potential fluctuations are slow compared to relaxation within the minima of the potential, and if the position of the minima does not fluctuate. Effective rates can be calculated; they describe the long-time dynamics of the system. Furthermore, we show the existence of a stationary solution of the Fokker-Planck equation that describes the motion within the fluctuating potential under some general conditions. We also show that a stationary solution of the rate equations with fluctuating rates exists.Comment: 18 pages, 2 figures, standard LaTeX2