Comparative analysis of the Žukauskas method and data from the OSU MASLWR test facility steam generator

Some of the next generation of small modular reactors have been designed with helically coiled steam generators integrated into the reactor vessel to enhance natural circulation. According to the developers of TASS/SMR, a one-dimensional thermal hydraulic code written to model the Korean Atomic Energy Research Institute's SMART reactor, the Žukauskas correlation, a heat transfer correlation designed for banks of straight tubes in crossflow, accurately models the heat transfer into helical steam generator tubes. Data has been collected using the Oregon State University Multi-Application Small Light Water Reactor (MASLWR) Test Facility to test whether the Žukauskas correlation can accurately predict the helical steam generator heat transfer coefficients for a natural circulation driven reactor. A one-dimensional, lumped parameter method was devised to use the limited instrumentation of the facility to calculate a temperature profile inside the tubes. From the calculated bulk fluid temperatures, wall temperatures were iteratively solved for and used to generate semi-local heat transfer coefficients. It was found that the instrumentation in the steam generator region of MASLWR Test Facility is too sparse to generate accurate heat transfer coefficients, but the calculated wall temperatures can be averaged over the length of the tubes to ind a good global wall temperature. This global wall temperature was used in a global analysis that found that the Žukauskas correlation works well when both systems are at high flow rates but becomes increasingly worse as the flow rates are lowered

Fiber optics communications; (230.7405) Wavelength conversion devices; (130.3730) Lithium niobate

Abstract: We present the results of an in-depth experimental investigation about all-optical wavelength conversion of a 100-Gb/s polarization-multiplexed (POLMUX) signal. Each polarization channel is modulated at 25 Gbaud by differential quadrature phase-shift keying (DQPSK). The conversion is realized exploiting the high nonlinear χ ©2009 Optical Society of Americ

Network properties of mixtures of protonated and deuterated polyethylene

The original version of this article contained an error in the legend to Figure 4. The yellow scale bar should have been defined as '~600 nm', not '~600 µm'. This has now been corrected in both the PDF and HTML versions of the article

Reduktion kupferhaltiger Schlackenschmelzen ueber reichem Kupferstein durch Aufblasen von Methan/Sauerstoff- bzw. Kohle/Luft-Gemischen Schlussbericht

With 11 refs., 14 tab., 14 figs.Copy held by FIZ Karlsruhe; available from UB/TIB Hannover / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

An unsupervised Hidden Markov Model-based system for the detection and classification of blue whale vocalizations off Chile

This paper analyzes the procedure used by FIFA up until 2018 to rank national football teams and define by random draw the groups for the initial phase of the World Cup finals. A predictive model is calibrated to form a reference ranking to evaluate the performance of a series of simple changes to that procedure. These proposed modifications are guided by a qualitative and statistical analysis of the FIFA ranking. We then analyze the use of this ranking to determine the groups for the World Cup finals. After enumerating a series of deficiencies in the group assignments for the 2014 World Cup, a mixed integer linear programming model is developed and used to balance the difficulty levels of the groups

Thermodynamics of emergent magnetic charge screening in artificial spin ice

Electric charge screening is a fundamental principle governing the behaviour in a variety of systems in nature. Through reconfiguration of the local environment, the Coulomb attraction between electric charges is decreased, leading, for example, to the creation of polaron states in solids or hydration shells around proteins in water. Here, we directly visualize the real-time creation and decay of screened magnetic charge configurations in a two-dimensional artificial spin ice system, the dipolar dice lattice. By comparing the temperature dependent occurrence of screened and unscreened emergent magnetic charge defects, we determine that screened magnetic charges are indeed a result of local energy reduction and appear as a transient minimum energy state before the system relaxes towards the predicted ground state. These results highlight the important role of emergent magnetic charges in artificial spin ice, giving rise to screened charge excitations and the emergence of exotic low-temperature configurations.Peer reviewe