The method of improving permeability of coal seams by freeze-fracturing is presented to accelerate the diffusion of coalbed gas into exploited wells. The pore structure of coal sample changes caused by freeze-fracturing were characterized by nuclear magnetic resonance (NMR) and scanning electron...

The authors draws the reader’s attention to the twin toxic hazards that is radiation and chemicals linger , the author effectively fused the pre-existent pollution concerns of urban and industrial reformers to the ecological sensitivities of resource conservation and wilderness...

The method of improving permeability of coal seams by freeze-fracturing is presented to accelerate the diffusion of coalbed gas into exploited wells. The pore structure of coal sample changes caused by freeze-fracturing were characterized by nuclear magnetic resonance (NMR) and scanning electron...

This paper presents a general theory that works out the relation between coherent risk measures, valuation bounds, and certain classes of portfolio optimization problems. It is economically general in the sense that it works for any cash stream spaces, be it in dynamic trading settings, one-step...

An investor faced with a contingent claim may eliminate risk by (super-)hedging in a financial market. As this is often quite expensive, we study partial hedges, which require less capital and reduce the risk. In a previous paper we determined quantile hedges which succeed with maximal...

For portfolio choice problems with proportional transaction costs, we discuss whether or not there exists a shadow price, i.e., a least favorable frictionless market extension leading to the same optimal strategy and utility. By means of an explicit counter-example, we show that shadow prices...