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Thermoacoustic systems have been a focus of recent research due to its structural simplicity, high reliability due to absence of moving parts, and can be driven by low grade energy such as fuel, gas, solar energy, waste heat etc. There has been extensive research on both standing wave and traveling wave systems. Towards the development of such systems, simulations can be carried out by several methods such as (a) solving the energy equation, (b) enthalpy flow model, (c) DeltaEC, a free software available from LANL, USA (d) Computational Fluid Dynamics (CFD) etc. We present here the simulation studies of standing wave and traveling wave thermoacoustic prime movers using CFD and DeltaEC. The CFD analysis is carried out using Fluent 6.3.26, incorporating the necessary boundary conditions with different working fluids at different operating pressures. The results obtained by CFD are compared with those obtained using DeltaEC. Also, the CFD simulation of the thermoacoustically driven refrigerator is presented. [ABSTRACT FROM AUTHOR]

This paper examines the two specific areas where the mortgage industry's transmission of "mispriced" assets into the financial system led to the deterioration of investor's confidence in the entire financial system. These two areas, the regulatory environment that created an asset bubble in mortgage based collateral and the rapid growth of structured instruments (including credit-based derivatives) in our view, significantly impacted the magnitude and scope of the problem. We show that each had a direct impact on the existing credit framework in different ways and adversely affected the risk assessment of mortgage related collateral. The exposure that financial institutions have to this "mispricing" of credit, in a variety of ways, led to the volatility observed in financial markets since the fall of 2008. We conclude the paper by emphasizing that future credit risk frameworks will require greater emphasis on consistent global standards regarding securities trading and risk management practices. Techniques and methods used for assessing the creditworthiness of financial obligations, collateral, securitizations, and counterparties are required not only to be robust but adhered to by the management of financial institutions and investors in general. We argue that until major reforms in regulation & financial product risk analysis are implemented, investor confidence will not return. Actions that will help the proposed "bailout" achieve its goal of restoring investor confidence and trust in the financial system are hereby suggested. [ABSTRACT FROM AUTHOR]