Incoherent dynamics in neutron-matter interaction

Coherent and incoherent neutron-matter interaction is studied inside a recently introduced approach to subdynamics of a macrosystem. The equation describing the interaction is of the Lindblad type and using the Fermi pseudopotential we show that the commutator term is an optical potential leading to well-known relations in neutron optics. The other terms, usually ignored in optical descriptions and linked to the dynamic structure function of the medium, give an incoherent contribution to the dynamics, which keeps diffuse scattering and attenuation of the coherent beam into account, thus warranting fulfilment of the optical theorem. The relevance of this analysis to experiments in neutron interferometry is briefly discussed.Comment: 15 pages, revtex, no figures, to appear in Phys. Rev.

Stationary states of an electron in periodic structures in a constant uniform electrical field

On the basis of the transfer matrix technique an analytical method to investigate the stationary states, for an electron in one-dimensional periodic structures in an external electrical field, displaying the symmetry of the problem is developed. These solutions are shown to be current-carrying. It is also shown that the electron spectrum for infinite structures is continuous, and the corresponding wave functions do not satisfy the symmetry condition of the problem.Comment: 10 pages (Latex), no figures, in the revised variant some mistakes in the English text are corrected and also the first two paragraphs in the Conclusion are refined (Siberian physical-technical institute at the Tomsk state university, Tomsk, Russia

Effects of Process Variables and Size Scale on Solidification Microstructure in Laser-Based Solid Freeform Fabrication of Ti-6Al-4V

Mechanical Engineerin

The Minkowski metric in non-inertial observer radar coordinates

We give a closed expression for the Minkowski (1+1)-dimensional metric in the radar coordinates of an arbitrary non-inertial observer O in terms of O's proper acceleration. Knowledge of the metric allows the non-inertial observer to perform experiments in spacetime without making reference to inertial frames. To clarify the relation between inertial and non-inertial observers the coordinate transformation between radar and inertial coordinates, also is given. We show that every conformally flat coordinate system can be regarded as the radar coordinate system of a suitable observer for a suitable parametrization of the observer worldline. Therefore, the coordinate transformation between arbitrarily moving observers is a conformal transformation and conformally invariant (1+1)-dimensional theories lead to the same physics for all observers, independently of their relative motion.Comment: Revtex4, 6 pages, 1 figur

Flight Determination of Drag of Normal-Shock Nose Inlets with Various Cowling Profiles at Mach Numbers from 0.9 to 1.5

External-drag data are presented for normal-shock nose inlets with NACA 1-series, parabolic, and conic cowling profiles. The tests were made at an angle of attack of 0 degrees by using rocket-propelled models in free flight at Mach numbers from 0.9 to 1.5. The Reynolds number based on body maximum diameter varied from 2.5 x 10 sup 6 to 5.5 x 10 sup 6. At maximum flow rate, the inlet models had about the same external drag at a Mach number of approximately 1.1, but at higher Mach numbers the sharp-lip conic cowling had the least drag. Blunting or beveling the lip of the conic cowling while keeping the fineness ratio constant resulted in drag coefficients slightly higher than for the sharp-lip conic cowling at maximum flow rate. At a mass-flow ratio of about 0.8, the conic cowlings with sharp, blunt, or beveled lips and the parabolic cowling all gave about the same drag. The higher drag of the NACA 1-49-300 cowling, compared with the blunt-lip conic cowling, is associated with the greater fullness back of the inlet

Photon Shot Noise Dephasing in the Strong-Dispersive Limit of Circuit QED

We study the photon shot noise dephasing of a superconducting transmon qubit in the strong-dispersive limit, due to the coupling of the qubit to its readout cavity. As each random arrival or departure of a photon is expected to completely dephase the qubit, we can control the rate at which the qubit experiences dephasing events by varying \textit{in situ} the cavity mode population and decay rate. This allows us to verify a pure dephasing mechanism that matches theoretical predictions, and in fact explains the increased dephasing seen in recent transmon experiments as a function of cryostat temperature. We investigate photon dynamics in this limit and observe large increases in coherence times as the cavity is decoupled from the environment. Our experiments suggest that the intrinsic coherence of small Josephson junctions, when corrected with a single Hahn echo, is greater than several hundred microseconds.Comment: 5 pages, 4 figures; includes Supporting Online Material of 6 pages with 5 figure

An analytic expression for the electronic correlation term of the kinetic functional

We propose an analytic formula for the non-local Fisher information functional, or electronic kinetic correlation term, appearing in the expression of the kinetic density functional. Such an explicit formula is constructed on the basis of well-founded physical arguments and a rigorous mathematical prescription

Making Round Bale Silage – Lessons Learned From an On-Farm Survey of Baleage in Kentucky

The ability to make silage in round bale packages allows producers to avoid rain damage and produce high quality stored forage. The proliferation of bale wrappers (both individual and inline types) has made this technology more available to producers. Although the process for making baleage is well documented, producers have experienced poor fermentation and in some cases botulism toxicity from baleage. The parameters of good silage are well known and include pH below 5.0 and lactic acid concentrations above 3% on a DM basis. However, tests of farmer- produced baleage reveals that often these target values are not achieved. To better understand the fermentation characteristics of Kentucky baleage, a survey was conducted of round bale silage samples from several Kentucky counties in 2017, 2018 and 2019. Moisture content (MC) at baling was the greatest determinant of fermentation success as measured by pH and lactic acid concentration. Moisture contents were highly variable, with more outside the recommended range of MC (40 to 60%) than within. Farmer practices including wilting time and equipment used were recorded for the 2019 samples. All the well-accepted practices for making baleage were confirmed in this survey (cutting on time, wilting to proper MC, dense bales, achieving and maintaining anaerobic storage conditions). Baleage samples exceeding 65% MC had elevated butyric acid concentrations, indicating secondary fermentation by clostridial bacteria

Fluctuating magnetic moments in liquid metals

We re-analyze literature data on neutron scattering by liquid metals to show that non-magnetic liquid metals possess a magnetic moment that fluctuates on a picosecond time scale. This time scale follows the motion of the cage-diffusion process in which an ion rattles around in the cage formed by its neighbors. We find that these fluctuating magnetic moments are present in liquid Hg, Al, Ga and Pb, and possibly also in the alkali metals.Comment: 17 pages, 5 figures, submitted to PR