On-Farm Flood Flow Capture – addressing flood risks and groundwater overdraft in the Kings Basin, with potential applications throughout the Central Valley

Project fact sheet prepared in cooperation with the USDA Natural Resources Conservation Service and the Kings River Conservation District

Basic considerations for designing a thesaurus for an information system for Social Science subjects with special reference to Jute trade

Gives in brief the main reasons for building up a Thesaurus to help the Information system of an economic unit to supply information to the States that management speedily, specifically and comprehensively. principles for building up a Thesaurus in a subject should be found out from the structure of the subject itself. The contention has been illustrated with two sample Thesauri compiled on the commodity Jute and a few countries involved in different types of economic union

Thermomagnetic history effects in SmMn2_2Ge2_2

The intermetallic compound SmMn$_2$Ge$_2$, displaying multiple magnetic phase transitions, is being investigated in detail for its magnetization behavior near the 145 K first order ferromagnetic to antiferromagnetic transition occuring on cooling, in particular for thermomagnetic history effects in the magnetization data. The most unusual finding is that the thermomagnetic irreversibility, [= M$^{FCW}$(T)-M$^{ZFC}$(T)] at 135 K is higher in intermediate magnetic field strengths. By studying the response of the sample (i.e., thermomagnetic irreversibility and thermal hysteresis) to different histories of application of magnetic field and temperature, we demonstrate how the supercooling and superheating of the metastable magnetic phases across the first order transition at 145 K contribute to overall thermomagnetic irreversibility.Comment: 15 pages, 5 figures, to appear in Physical Review

PARTICLE CLUSTERS IN FLUIDIZED BEDS

Accurately predicting the entrainment rate is important in designing a commercial fluidized bed. However, most correlations fall short in providing an accurate prediction of the entrainment rate. Many correlations assume that smaller particles have a higher entrainment rate than larger particles; but, this is often not the case. Smaller particles can, and often do, have lower effective entrainment rates than larger particles. This has been presumed from several different experiments. In one case, the entrainment rate of FCC catalyst fines was measured at different fluidized bed heights and found that higher entrainment fluxes were observed at lower bed heights (i.e., higher disengaging heights). In a second case, it was found in a batch entrainment test that with an initial high concentration the fines level in the entrainment flux was very low. As the fines were gradually elutriated away, the entrainment flux increased dramatically. Following a dramatic increase to a maximum, the entrainment flux then exhibited the classical batch exponential decay as the fines were elutriated from the fluidized bed. Recently, high speed video of particles in a fluidized bed freeboard was able to image and track large clusters of particles in the range of 200 microns to 1000 microns when the bed material had a mean particle size of only 25 microns. All of these findings suggests that fine particles in many materials are clumping or clustering. This increases their effective particle diameter which reduces the entrainment rate. The clumps appear to be formed in the fluidized bed, and are ejected into the freeboard. High-speed videos obtained using observations through a borescope inserted into a fluidized bed at PSRI have confirmed the presence of clusters in fluidized beds. Such a phenomenon has many implications regarding how entrainment may be influenced by fines level, bed height, baffles, jet velocity at the distributor, etc

PARTICLE ATTRITION MEASUREMENTS USING A JET CUP

Particle attrition is usually detrimental as it negatively affects product quality and process cost. Thus, it is important to know how particles attrit under relevant operating conditions. Small jet cup attrition test devices (such as the Davison Jet Cup) are typically used to measure relative particle attrition for fluidized beds and risers. Ideally, the attrition rates measured in these laboratory units provide a relative indication of how the materials will behave in the commercial unit. Most jet cup devices have a cylindrical configuration. However, Particulate Solid Research, Inc. (PSRI) has found that a cylindrical jet cup attrition measurement may not be effective in providing accurate attrition rankings. Attrition index rankings from a cylindrical jet cup and a 0.3-meter (12-inch) diameter, pilot-plant fluidized bed unit did not agree with each other. It was subsequently found in cold flow studies at PSRI in Plexiglas™ jet cup models which showed that many of the solids were nearly stagnant, even at high inlet jet velocities. Approximately 30 to 50% of the particle sample in a cylindrical jet cup was not in motion and was not exposed to the solid stresses needed for accurate particle attrition measurements. Computational Fluid Dynamics (CFD) results confirmed this finding. As a result, it is unlikely that relevant attrition rankings can be reliably determined from cylindrical jet cup studies because a significant portion of the particle sample is not exposed to sufficient solid stresses to cause attrition. Only by insuring that the entire sample is under a similar amount of stress can attrition be accurately linked to inlet jet velocity and directly compared with different materials. This paper discusses the development of a conical jet cup device that allows all of the sample particles to experience similar solids stresses. The rankings of the attrition indices from the conical jet cup were found to correspond to the rankings observed in pilot-plant attrition tests. The agreement in rankings obtained with the new conical jet cup was not observed with the traditional cylindrical jet cup

Disorder and thermally driven vortex-lattice melting in La{2-x}Sr{x}CuO{4} crystals

Magnetization measurements in La{2-x}Sr{x}CuO{4} crystals indicate vortex order-disorder transition manifested by a sharp kink in the second magnetization peak. The transition field exhibits unique temperature dependence, namely a strong decrease with temperature in the entire measured range. This behavior rules out the conventional interpretation of a disorder-driven transition into an entangled vortex solid phase. It is shown that the transition in La{2-x}Sr{x}CuO{4} is driven by both thermally- and disorder-induced fluctuations, resulting in a pinned liquid state. We conclude that vortex solid-liquid, solid-solid and solid to pinned-liquid transitions are different manifestations of the same thermodynamic order-disorder transition, distinguished by the relative contributions of thermal and disorder-induced fluctuations.Comment: To be published in phys. Rev. B Rapid Com

A study of supercooling of the disordered vortex phase via minor hysteresis loops in 2H-NbSe_2

We report on the observation of novel features in the minor hysteresis loops in a clean crystal of NbSe_2 which displays a peak effect. The observed behavior can be explained in terms of a supercooling of the disordered vortex phase while cooling the superconductor in a field. Also, the extent of spatial order in a flux line lattice formed in ascending fields is different from (and larger than) that in the descending fields below the peak position of the peak effect; this is attributed to unequal degree of annealing of the state induced by a change of field in the two cases.Comment: 5 pages of text + 6 figures, submitted to Phys. Rev.

Magnetocapacitive La0.6Sr0.4MnO3 0.7Pb(Mg0.33Nb0.67)O3 0.3PbTiO3 epitaxial heterostructures

Epitaxial heterostructures of La0.6Sr0.4MnO3 0.7Pb(Mg0.33Nb0.67)O3 0.3PbTiO3 were fabricated on LaNiO3 coated LaAlO3 (100) substrates by pulsed laser ablation. Ferromagnetic and ferroelectric hysteresis established their biferroic nature. Dielectric behviour studied under different magnetic fields over a wide range of frequency and temperatures revealed that the capacitance in these heterostructures varies with the applied magnetic field. Appearance of magnetocapacitance and its dependence on magnetic fields, magnetic layer thickness, temperature and frequency indicated a combined contribution of strain mediated magnetoelectric coupling, magnetoresistance of the magnetic layer and Maxwell Wagner effect on the observed properties