Heat conduction and Wiedemann-Franz Law in disordered Luttinger Liquids

We consider heat transport in a Luttinger liquid (LL) with weak disorder and study the Lorenz number for this system. We start at a high-$T$ regime, and calculate both the electrical and thermal conductivities using a memory function approach. The resulting Lorenz number $L$ is independent of $T$ but depends explicitly on the LL exponents. Lowering $T$, however, allows for a renormalization of the LL exponents from their bare values by disorder, causing a violation of the Wiedemann-Franz law. Finally, we extend the discussion to quantum wire systems and study the wire size dependence of the Lorenz number.Comment: 4 pages, 1 eps figure; Changes made to address Referees' comment

Hydrodynamics of internal solitons and a comparison of SIR-A and SIR-B data with ocean measurements

Large internal solitary waves have been observed by Shuttle SIR-A and SIR-B at locations in the Andaman Sea and the New York Bight. Satellite imagery and oceanographic measurements are used in conjunction with hydrodynamic interaction and electromagnetic scattering models to estimate the expected SAR image intensity modulations associated with the internal waves. There is reasonable agreement between the predicted and observed internal wave signatures

Use of Cemented Rock Fill for Enhanced Pillar Recovery in Area 1 of the Doe Run Company

Area 1 of Doe Run Company’s Buick North Mine was selected for placement of cemented rockfill (CRF) to “trap” or encapsulate select pillars. This method of “trapping” pillars takes advantage of the passive confinement effect of CRF to increase the post-peak load bearing ability of trapped pillars so that other ore bearing pillars can be extracted while still maintaining local and global mine stability. A total of 73 pillars in this area were extracted from October 1998 thru January 2002. Thirteen of 73 pillars were totally trapped by CRF (i.e., the pillars were totally encased in CRF). Eight of the thirteen pillars trapped with CRF were instrumented with extensometers to monitor deformations that occurred during the extraction process. Of the remaining pillars, 18 were not confined in CRF; and the remaining pillars were partially trapped to some degree (one or more free faces). Data collected from the instruments showed that the rate at which pillars deformed (or converged) slowed and that most of the instrumented pillars were virtually unaffected until the late stages of pillar extraction. Two of the instrumented pillars showed considerable initial vertical strain at the onset of pillar extraction. The rate at which these pillars converged slowed as additionally pillars were extracted. This was attributed to the passive confinement effect of CRF in which this material compacts (the density increases) as the pillar dilates, becomes stiffer, and thus provides an increase in confining pressures or stress that acts to restrict pillar dilation. This study has provided valuable insight into the behavior of trapped roof supporting pillars during the extraction process. Future research is being undertaken to clearly develop procedures to predict the behavior CRF trapped pillars during extraction of other economically valuable pillars

Conference Educates, Uplifts Nebraska Women in Agriculture

Women in agriculture are business partners, owners and operators; they oversee financial and human resources and keep farms and ranches running. This was the message more than 250 women heard at the 33rd annual Nebraska Women in Agriculture Conference February 22 and 23 in Kearney

Conference Educates, Uplifts Nebraska Women in Agriculture

Women in agriculture are business partners, owners and operators; they oversee financial and human resources and keep farms and ranches running. This was the message more than 250 women heard at the 33rd annual Nebraska Women in Agriculture Conference February 22 and 23 in Kearney

Disorder Effects in Fluctuating One-Dimensional Interacting Systems

The zero temperature localization of interacting electrons coupled to a two-dimensional quenched random potential, and constrained to move on a fluctuating one-dimensional string embedded in the disordered plane, is studied using a perturbative renormalization group approach. In the reference frame of the electrons the impurities are dynamical and their localizing effect is expected to decrease. We consider several models for the string dynamics and find that while the extent of the delocalized regime indeed grows with the degree of string fluctuations, the critical interaction strength, which determines the localization-delocalization transition for infinitesimal disorder,does not change unless the fluctuations are softer than those of a simple elastic string.Comment: 15 page

Projecting flood hazard under climate change: an alternative approach to model chains

Flood hazard projections under climate change are typically derived by applying model chains consisting of the following elements: "emission scenario – global climate model – downscaling, possibly including bias correction – hydrological model – flood frequency analysis". To date, this approach yields very uncertain results, due to the difficulties of global and regional climate models to represent precipitation. The implementation of such model chains requires major efforts, and their complexity is high. <br><br> We propose for the Mekong River an alternative approach which is based on a shortened model chain: "emission scenario – global climate model – non-stationary flood frequency model". The underlying idea is to use a link between the Western Pacific monsoon and local flood characteristics: the variance of the monsoon drives a non-stationary flood frequency model, yielding a direct estimate of flood probabilities. This approach bypasses the uncertain precipitation, since the monsoon variance is derived from large-scale wind fields which are better represented by climate models. The simplicity of the monsoon–flood link allows deriving large ensembles of flood projections under climate change. We conclude that this is a worthwhile, complementary approach to the typical model chains in catchments where a substantial link between climate and floods is found