Properties of KCo2_2As2_2 and Alloys with Fe and Ru: Density Functional Calculations

Electronic structure calculations are presented for KCo$_2$As$_2$ and alloys with KFe$_2$As$_2$ and KRu$_2$As$_2$. These materials show electronic structures characteristic of coherent alloys, with a similar Fermi surface structure to that of the Fe-based superconductors, when the $d$ electron count is near six per transition metal. However, they are less magnetic than the corresponding Fe compounds. These results are discussed in relation to superconductivity.Comment: 5 page

Electronic Structure and Bulk Spin Valve Behavior in Ca3_3Ru2_2O7_7

We report density functional calculations of the magnetic properties and Fermiology of Ca$_3$Ru$_2$O$_7$. The ground state consists of ferromagnetic bilayers, stacked antiferromagnetically. The bilayers are almost but not exactly half-metallic. In the ferromagnetic state opposite spin polarizations are found for in-plane and out-of-plane transport. Relatively high out of plane conductivity is found for the majority spin, which is relatively weakly conductive in-plane. In the ground state in-plane quantities are essentially the same, but the out of plane transport is strongly reduced.Comment: 5 page

Hydrodynamic signatures of stationary Marangoni-driven surfactant transport

We experimentally study steady Marangoni-driven surfactant transport on the interface of a deep water layer. Using hydrodynamic measurements, and without using any knowledge of the surfactant physico-chemical properties, we show that sodium dodecyl sulphate and Tergitol 15-S-9 introduced in low concentrations result in a flow driven by adsorbed surfactant. At higher surfactant concentration, the flow is dominated by the dissolved surfactant. Using Camphoric acid, whose properties are {\it a priori} unknown, we demonstrate this method's efficacy by showing its spreading is adsorption dominated

Rendering PostScript^TM fonts on FPGAs

This paper describes how custom computing machines can be used to implement a simple outline font processor. An FPGA based co-processor is used to accelerate the compute intensive portions of font rendering. The font processor builds on several PostScript components previously presented by the authors to produce a system that can rapidly render fonts. A prototype implementation is described followed by an explanation of how this could be extended to build a complete system

Conflict and inequality in surface irrigation: a socio-ecological perspective

This paper attempts to understand the role of institutions and governance, in explaining unequal access to canal water under different rules of the game. Two states at different levels of agricultural productivity with different rules of distribution of canal water are chosen to study the problem at project level. While Bihar, at low level of agricultural productivity, represents absence of scientific method of distribution of water, Punjab offers high level of agricultural productivity with the warabandi system. The two case studies offer interesting similarities and dissimilarities in terms of unequal access to water by the tail enders and mechanisms needed to mitigate this inequality. Some similarities are: (a) the tail enders suffer the most with low access to water forcing them to adopt only low water intensive crops in comparison to the head reach and mid reach farmers; and (b) the farmers supplement canal water with ground water. The dissimilarities noticed are: (a) while over exploitation of ground water in Punjab has reached levels beyond natural recharge of aquifers in several places; in Bihar, with low withdrawal of ground water and natural endowment of high water table, such a situation has not arisen; (b) the breaking of canal and water courses for own benefit by the powerful with political clout is rampant in Bihar, rarely attracting a penalty from the irrigation department; (c) the water market for tubewell water (Rs.70 to 80 per hour) has developed in Bihar partly mitigating inequality in access to canal water by the tail enders; no such phenomenon is common in Punjab. The plausible reason for the low density of tubewells in Bihar in contrast to Punjab is low incomes making affordability of tubewell an issue, and (d) cooperative efforts by farmers to lay down pipes through neighbors’ plots to minimize loss of water has succeeded in Punjab; in Bihar such efforts succeeded initially at a small scale but could not sustain without government assistance. The absence of scientific rule for distribution of canal water and the weak canal governance system aggravates the misery of tail enders. In such a scenario, the mitigation of unequal access to water by the tail enders is facilitated by the development of water markets at high cost in a complex situation with tiny holdings and lack of cooperation among the farmers.Length: pp.808-818CanalsWater distributionCrop managementGroundwaterWater market