The Abundance, Size, and Spacing of Lakes and Reservoirs Connected to River Networks

Descriptions of river network topology do not include lakes/reservoirs that are connected to rivers. We describe the properties and scaling patterns of river network topology across the contiguous United States: how lake/reservoir abundance, median lake/reservoir size, and median lake/reservoir spacing change with river size. Typically, lake/reservoir abundance decreases, median lake/reservoir size increases, but median lake/reservoir spacing is uniform across river size. There is a characteristic lake/reservoir size of 0.01–0.05 km2 and a characteristic lake/reservoir spacing of 1–5 km that shifts to 27–61 km in larger rivers. Climate explains more of the variance in river network topology than both glacial history and constructed reservoirs. Our results provide conceptual models for building river network topologies to assess how lake/reservoir abundance, size, and spacing effect the transport, storage, and cycling of water, materials, and organisms across networks

Cross-National Logo Evaluation Analysis: An Individual Level Approach

The universality of design perception and response is tested using data collected from ten countries: Argentina, Australia, China, Germany, Great Britain, India, the Netherlands, Russia, Singapore, and the United States. A Bayesian, finite-mixture, structural-equation model is developed that identifies latent logo clusters while accounting for heterogeneity in evaluations. The concomitant variable approach allows cluster probabilities to be country specific. Rather than a priori defined clusters, our procedure provides a posteriori cross-national logo clusters based on consumer response similarity. To compare the a posteriori cross-national logo clusters, our approach is integrated with Steenkamp and Baumgartner’s (1998) measurement invariance methodology. Our model reduces the ten countries to three cross-national clusters that respond differently to logo design dimensions: the West, Asia, and Russia. The dimensions underlying design are found to be similar across countries, suggesting that elaborateness, naturalness, and harmony are universal design dimensions. Responses (affect, shared meaning, subjective familiarity, and true and false recognition) to logo design dimensions (elaborateness, naturalness, and harmony) and elements (repetition, proportion, and parallelism) are also relatively consistent, although we find minor differences across clusters. Our results suggest that managers can implement a global logo strategy, but they also can optimize logos for specific countries if desired.adaptation;standardization;Bayesian;international marketing;design;Gibbs sampling;concomitant variable;logos;mixture models;structural equation models

Magnetic-field and current-density distributions in thin-film superconducting rings and disks

We show how to calculate the magnetic-field and sheet-current distributions for a thin-film superconducting annular ring (inner radius a, outer radius b, and thickness d<<a) when either the penetration depth obeys lambda < d/2 or, if lambda > d/2, the two-dimensional screening length obeys Lambda = 2 lambda^2/d << a for the following cases: (a) magnetic flux trapped in the hole in the absence of an applied magnetic field, (b) zero magnetic flux in the hole when the ring is subjected to an applied magnetic field, and (c) focusing of magnetic flux into the hole when a magnetic field is applied but no net current flows around the ring. We use a similar method to calculate the magnetic-field and sheet-current distributions and magnetization loops for a thin, bulk-pinning-free superconducting disk (radius b) containing a dome of magnetic flux of radius a when flux entry is impeded by a geometrical barrier.Comment: 10 pages, 13 figure

Meissner state in finite superconducting cylinders with uniform applied magnetic field

We study the magnetic response of superconductors in the presence of low values of a uniform applied magnetic field. We report measurements of DC magnetization and AC magnetic susceptibility performed on niobium cylinders of different length-to-radius ratios, which show a dramatic enhance of the initial magnetization for thin samples, due to the demagnetizing effects. The experimental results are analyzed by applying a model that calculates the magnetic response of the superconductor, taking into account the effects of the demagnetizing fields. We use the results of magnetization and current and field distributions of perfectly diamagnetic cylinders to discuss the physics of the demagnetizing effects in the Meissner state of type-II superconductors.Comment: Accepted to be published in Phys. Rev. B; 15 pages, 7 ps figure

HD Diesel engine equipped with a bottoming Rankine cycle as a waste heat recovery system. Part 2: Evaluation of alternative solutions

A theoretical investigation has been performed on the feasibility of introducing a waste heat recovery (WHR) system in a two-stage turbocharged HDD engine. The WHR is attained by introducing a Rankine cycle, which uses an organic substance or directly water as a working fluid depending on energetic performance considerations. A previous research was carried out to evaluate the maximum potential of this WHR concept, a conventional layout was used for coupling the Rankine cycle to the thermal engine. The objective of the present research is to broad the scope of the previous analysis by considering new alternative solutions for the problems related to the coupling between the WHR Rankine cycle and the thermal engine. These solutions are based on adapting one of the turbochargers by removing its turbine and trying to recover the energy by the Rankine cycle. Finally, the turbine of the Rankine cycle supplies the recovered energy directly to the compressor of this turbocharger. Thus, in these layouts the coupling is simpler as it involves only two turbomachines, which are supposed to share a similar rotating speed. From the results of the global energy balance, these alternative layouts produce slight benefits in fuel consumption but in all cases these benefits are lower compared to those attained with conventional layouts. © 2011 Published by Elsevier Ltd. All rights reserved.This work was partially funded by "Programa de Apoyo a la Investigacion y Desarrollo de la Universidad Politecnica de Valencia".Serrano Cruz, JR.; Dolz Ruiz, V.; Novella Rosa, R.; García Martínez, A. (2012). HD Diesel engine equipped with a bottoming Rankine cycle as a waste heat recovery system. Part 2: Evaluation of alternative solutions. Applied Thermal Engineering. 36:279-287. doi:10.1016/j.applthermaleng.2011.10.024S2792873

Off-limb (spicule) DEM distribution from SoHO/SUMER observations

In the present work we derive a Differential Emission Measure (DEM) dis- tribution from a region dominated by spicules. We use spectral data from the Solar Ultraviolet Measurements of Emitted Radiation (SUMER) spectrometer on-board the Solar Heliospheric Observatory (SoHO) covering the entire SUMER wavelength range taken off-limb in the Northern polar coronal hole to construct this DEM distribution using the CHIANTI atomic database. This distribution is then used to study the thermal properties of the emission contributing to the 171 {\AA} channel in the Atmospheric Imaging Assembly (AIA) on-board the Solar Dynamics Observatory (SDO). From our off-limb DEM we found that the radiance in the AIA 171 {\AA} channel is dominated by emission from the Fe ix 171.07 {\AA} line and has sparingly little contribution from other lines. The product of the Fe ix 171.07 {\AA} line contribution function with the off-limb DEM was found to have a maximum at logTmax (K) = 5.8 indicating that during spicule observations the emission in this line comes from plasma at transition region temperatures rather than coronal. For comparison, the same product with a quiet Sun and prominence DEM were found to have a maximum at logT max (K) = 5.9 and logTmax (K) = 5.7, respectively. We point out that the interpretation of data obtained from the AIA 171 {\AA} filter should be done with foreknowledge of the thermal nature of the observed phenomenon. For example, with an off-limb DEM we find that only 3.6% of the plasma is above a million degrees, whereas using a quiet Sun DEM, this contribution rises to 15%.Comment: 12 pages, 6 figures accepted by Solar Physic

Vortex phase transformations probed by the local ac response of Bi_{2}Sr_{2}CaCu_{2}O_{8+\delta} single crystals with various doping

The linear ac response of the vortex system is measured locally in Bi-2212 single crystals at various doping, using a miniature two-coil mutual-inductance technique. It was found that a step-like change in the local ac response takes place exactly at the first-order transition (FOT) temperature T_{FOT}(H) determined by a global dc magnetization measurement. The T_{FOT}(H) line in the H-T phase diagram becomes steeper with increasing doping. In the higher-field region where the FOT is not observed, the local ac response still shows a broadened but distinct feature, which can be interpreted to mark the growth of a short-range order in the vortex system.Comment: 4 pages, including 5 eps figure

Random walk on the range of random walk

We study the random walk X on the range of a simple random walk on ℤ d in dimensions d≥4. When d≥5 we establish quenched and annealed scaling limits for the process X, which show that the intersections of the original simple random walk path are essentially unimportant. For d=4 our results are less precise, but we are able to show that any scaling limit for X will require logarithmic corrections to the polynomial scaling factors seen in higher dimensions. Furthermore, we demonstrate that when d=4 similar logarithmic corrections are necessary in describing the asymptotic behavior of the return probability of X to the origin