Magnetic Properties of the Novel Low-Dimensional Cuprate Na5RbCu4(AsO4)4Cl2

The magnetic properties of a new compound, Na5RbCu4(AsO4)4Cl2 are reported. The material has a layered structure comprised of square Cu4O4 tetramers. The Cu ions are divalent and the system behaves as a low-dimensional S=1/2 antiferromagnet. Spin exchange in Na5RbCu4(AsO4)4Cl2 appears to be quasi-two-dimensional and non-frustrated. Measurements of the bulk magnetic susceptibility and heat capacity are consistent with low-dimensional magnetism. The compound has an interesting, low-entropy, magnetic transition at T = 17 K.Comment: 4 pages, 5 figure

Mass Influxes and Protection in Europe: A Reflection on a Temporary Episode of an Enduring Problem

This article assesses Temporary Protection (TP) in Europe in response to refugee crises. In 2001 the European Union (EU) adopted a Directive for TP to provide a regional response to a mass influx. It was considered that TP offered a double-win: addressing protection needs of asylum seekers, while enabling states to maintain control based on the understanding that asylum seekers would return home after a short period of stay. The Directive has been endorsed in UNHCR Guidelines on ‘Temporary Protection or Stay Arrangements’ (2014). Notwithstanding, the analysis in this article indicates that TP was a strategy that failed: it did not give states control nor promote solidarity between them. Failure explains its absence in the responses to the 2015–16 crisis. However, national forms of TP have re-emerged signalling efforts to re-assert control in the face of an enduring problem

Increased brightness of the lunar surface

Mechanisms causing increased brightness of lunar surface - solar flare proton and electron irradiatio

Quantitative study of molecular N_2 trapped in disordered GaN:O films

The structure of disordered GaN:O films grown by ion-assisted deposition is investigated using x-ray absorption near-edge spectroscopy and Raman spectroscopy. It is found that between 4 and 21 % of the nitrogen in the films is in the form of molecular N_2 that interacts only weakly with the surrounding matrix. The anion to cation ratio in the GaN:O host remains close to unity, and there is a close correlation between the N_2 fraction, the level of oxygen impurities, and the absence of short-range order in the GaN:O matrix.Comment: 5 pages, 3 figure

Channel flow modeling of impingement cooling of a rotating turbine blade

Local heat transfer distributions in impingement cooling have been measured by Kreatsoulas and Prieser for a range of conditions which model those in actual turbine blades, including the effects of rotation. These data were reported as local Nusselt numbers, but referred to coolant supply conditions. By means of a channel flow modeling of the flow in the supply and impingement passages, the same data are here presented in terms of local Nusselt number distributions such as are used in design. The results in this form are compared to the nonrotating impingement results of Chupp and to the rotating but nonimpingement results of Morris. Rotation reduces the mean Nusselt numbers from these found by Chupp by about 30 percent, and introduces important radial variations which are sensitive to rotation and to leading edge stagger angle

Spatial Equilibrium Analysis of the U.S. Hard Red Spring Wheat Industry under Alternative Transportation Rate Structures

Industrial Organization,

Escaping Nash inflation

Mean dynamics govern convergence to rational expectations equilibria of self-referential systems under least squares learning. We highlight escape dynamics that propel away from a rational expectations equilibrium under fixed-gain recursive learning schemes. These learning schemes discount past observations. In a model with a unique self-confirming equilibrium, we show that the destination of the escape dynamics is an outcome associated with government discovery of too strong a version of the natural rate hypothesis. That destination is not sustainable as a self-confirming equilibrium but is visited recurrently. The escape route dynamics cause recurrent outcomes close to the Ramsey (commitment) inflation rate in a model with an adaptive government. JEL Classification: E3, E52, E58

U.S./CANADA GRAIN HANDLING AND TRANSPORTATION SYSTEMS

The United States and Canada have developed very different grain handling and transportation systems (GHTSs) over the last several decades to compete for global and domestic markets in Canada and the United States under CUSTA. Because the grain industries in both countries face long distance hauls, GHTSs are critically important to their operations and to producer returns. There has been considerable pressure for change in Canada's grain handling and transportation sector. Some industry trends, such as the rationalization of elevators in the Prairies and investments in new high through-put facilities, are being driven by market and competitive forces. Changes in grain handling, reciprocal access to marketing functions, and elimination of rate caps may have a significant impact on cross-border grain flows. Canadian Transport announced reforms to improve the efficiency of its GHTS. Possible multi-level effects, created by the reform package, would affect the grain flow from Canada to the United States. The most significant reforms include 'port buying' by the Canadian Wheat Board, which would remove the Board's control over internal logistics and shipping, and replacement of the current maximum railway rate scale with a cap on annual railway revenues for grain shipments.Canadian Wheat Board (CWB), Grain Trade, Grain Transportation and Handling System (GHTS), Rail Rate, Railcar Allocation, Rationalization, Rate Cap, Reciprocal Access, Regulation, Reform Package., Crop Production/Industries,

Comparison of Material Properties and Microstructure of Specimens Built Using the 3D Systems Vanguard HS and Vanguard HiQ+HSSLS Systems

The HiQ upgrade to the 3D Systems Vanguard selective laser sintering (SLS) machine incorporates a revised thermal calibration system and new control software. The paper compares the tensile modulus, tensile strength, elongation at break, flexural modulus, Izod impact resistance and microstructure of two batteries of standard specimens built from recycled Duraform PA (Nylon 12). The first set is built on a Vanguard HS system and the second on the same system with the HiQ upgrade installed. The upgrade reduces user intervention, decreases total build time and improves surface finish. However, using the default processing parameters, tensile, flexure and impact properties are all found to decline after the upgrade is installed.Mechanical Engineerin