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LUCINIO JÚDEZ ROSARIO DE ANDRÉS MIGUEL IBÁÑEZ ELVIRA URZAINQUI 《Natural Resource Modeling》2011,24(3):297-315
Abstract This paper aims to determine the minimum agri‐environmental premium per hectare that farmers should receive to reduce crop irrigation. To this end, the authors develop a mixed‐integer quadratic model using a new methodology based on traditional positive mathematical programming, which allows the inclusion in the model of crop variants that are not present in the baseline situation of the farms. What is shown is that the results obtained with this new methodology, using the cost average approach of calibration, are the same as those obtained with an empirical method, when there is no change of crop distribution after the changeover from irrigated to nonirrigated farms. The theoretical results are compared with those obtained using the calibration with exogenous elasticities and are illustrated numerically for a representative farm of an area around Spain's Tablas de Daimiel in which the use of groundwater for crop irrigation has led to the ongoing deterioration of wetlands that depend on the same source of water, endangering the region's environmental sustainability. 相似文献
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The Zeeman effect of the R absorption lines for the pure compound 2[Cr(en)3Cl3]KCl.6H2O has been measured photographically, using a strong pulsed magnet with fields of up to 200 000 gauss at 77 K. The results indicate g ∥ (4 A 2) = 1·82 , g ⊥(4 A 2) = 1·90 with g ∥(ē) = -1·82 and g ∥ (2ā) = 1·82. The uncertainties are of the order of ± 0·05. 相似文献
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Liron Shavit‐Hadar Dmitry M. Rein Rafail Khalfin Ann E. Terry Guido W. J. C. Heunen Yachin Cohen 《Journal of Polymer Science.Polymer Physics》2007,45(13):1535-1541
The effect of compaction conditions on UHMWPE fibers is examined by microbeam X‐ray diffraction (WAXS) and scanning electron microscopy (SEM). The morphological observations indicate that melting occurs during compaction both on the surface of the fiber as well as in its internal regions. In addition, the recrystallized phase is nucleated on the fiber surface, possibly epitaxially. The recrystallized phase that originates from the internal regions of the fiber retains the initial highly oriented structure. WAXS microbeam measurements do not show any significant core‐shell structure in compacted single fibers. Considering the overall characteristics of the melting process during compaction, we can conclude that the hexagonal phase that appears upon heating of the fibers under moderate pressure is responsible for good adhesion of the fibers to each other, even more significantly than surface melting, especially because of its ability to retain the high orientation of the chains in the fibers. This information is relevant for understanding the formation and microstructure of the matrix component in the self‐reinforced composites fabricated by compaction. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 1535–1541, 2007 相似文献
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Dmitry Goldring Mark Botoshansky Rafail L. Khalfin Boris Pertsikov Gennady Nisnevitch Victor Ponomarev Igor Zaltzman Arie Gutman Menahem Kaftory 《Acta Crystallographica. Section C, Structural Chemistry》2004,60(12):o843-o846
The crystal structures of three solvates of zafirlukast [systematic name: cyclopentyl N‐{1‐methyl‐3‐[2‐methyl‐4‐(o‐tolylsulfonylaminocarbonyl)benzyl]‐1H‐indol‐5‐yl}carbamate], viz. the monohydrate, C31H33N3O6S·H2O, (I), the methanol solvate, C31H33N3O6S·CH3OH, (II), and the ethanol solvate, C31H33N3O6S·C2H5OH, (III), have been determined by single‐crystal X‐ray diffraction analysis. All three compounds crystallize in the monoclinic crystal system. Zafirlukast adopts a similar Z‐shaped conformation in all three solvates. The methanol and ethanol solvates are isostructural. The packing of the zafirlukast molecules in all three crystal structures is similar and is expressed by hydrogen‐bonded molecules that are related by translation, along (101) in (I) and along the b axis in (II) and (III). The methanol and ethanol solvent molecules are hydrogen bonded to two molecules of zafirlukast. The water molecule, on the other hand, acts as a connector via hydrogen bonds between three molecules of zafirlukast. The solvent molecules are not released at temperatures below the melting points of the solvates. 相似文献
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A system of statistical equations has been derived to analyze the behavior of nonequilibrium collisionless quark-gluon plasmas in strong gravitational fields at superhigh temperatures (T < T
KP =1/8·(m
t
c
2/k) = 2.5·1014 K with mt being the mass of t-quark) and densities (1024 g/cm3). It has been shown that in a system where perturbations appear which are accompanied by an increase in the temperature over Tcr, an explosion occurs. This explosion is characterized by an anomalous prevalence of high particle velocities and leads to the formation of flows of high-energy hadrons. 相似文献
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V. D. Ashkenazy M. Bonaldi G. Jung I. B. Khalfin B. Ya. Shapiro S. Vitale 《Solid State Communications》1994,90(12):779-782
Random telegraph noise voltages developing across current biased granular high-Tc films interact with the system of Abrikosov vortices pinned inside the grains through random Lorentz forces caused by the flow of random currents in the film. Viscous relaxation of vortices opposes random forces and leads to the attenuation of the low frequency part of the observed spectra of the voltage noise. The theoretical model has been created and discussed. The predictions of the model have been verified experimentally by observations of a peak in the random noise spectra recorded for granular YBaCuO thin film strips immersed in a weak magnetic field and biased with a dc current flow above the critical current. It has been found that the peak position and its changes with charging random telegraph switching rate are in a good agreement with the theoretical predictions. 相似文献
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