A thermal lattice Boltzmann model for micro/nano-flows

The dynamic behavior of charged micro and nanofluids plays a crucial role in a large variety of industrial and biological processes. Such dynamic behavior is characterized by the simultaneous occurrence of several competing mechanisms, such as electrostatic interactions, viscous dissipation and hydrodynamic effects, often taking place in complex geometries. This paper focuses on a thermal lattice Boltzmann model for micro/nano-flows

Effects of rarefaction on cavity flow in the slip regime

The Navier-Stokes-Fourier equations, with boundary conditions that account for the effects of velocity-slip and temperature-jump, are compared to the direct simulation Monte Carlo method for the case of a lid-driven micro-cavity. Results are presented for Knudsen numbers within the slip-flow regime where the onset of nonequilibrium effects are usually observed. Good agreement is found in predicting the general features of the velocity field and the recirculating flow. However, although the steady-state pressure distributions along the walls of the driven cavity are generally in good agreement with the Monte Carlo data, there is some indication that the results are starting to show noticeable differences, particularly at the separation and reattachment points. The modified Navier-Stokes-Fourier equations consistently overpredict the maximum and minimum pressure values throughout the slip regime. This highlights the need for alternative boundary formulations or modeling techniques that can provide accurate and computationally economic solutions over a wider range of Knudsen numbers

Micro-scale cavities in the slip - and transition - flow regimes

Differences between Navier-Stokes-Fourier (NSF) slip/jump solutions and direct simulation Monte-Carlo (DSMC) computations are highlighted for a micro lid-driven cavity problem. The results indicate a need for better modelling techniques which at the same time retain low computational cost of NSF models. We also highlight the fact thatmany micro-flows that have been considered are simple planar flows and typical classification systems are defined on such flows. We show that for complex flows, such as thedriven cavity, non-equilibrium effects are more appreciable and their onset occurs at lower Knudsen numbers than expected

Immobilization of Fission Iodine by Reaction with a Fullerene Containing Carbon Compound and Insoluble Natural Matrix

Observations related to the oxidation of iodide to iodine (I2) or hypoiodic acid (HIO) by MnO2 were continued. The formation of triiodide presumable involves the adsorption of iodide onto the MnO2 surface (perhaps displacing a surface hydroxyl group). The iodide should be subsequently oxidized and released back into solution as IOH or I2, which rapidly forms I3 -. The kinetic data has been modeled as a first order process. First order rate constants have been obtained for the formation of iodine in the presence of MnO2. The increase in iodide oxidation rates with MnO2 concentration is evident in the data. The reaction rate increases with iodide concentration although the dependence is not first order (an order of 1.4 appear to fit the data). The oxidation rate also increases with temperature and has a apparent activation energy of 16.2 kJ/mol

Immobilization of Fission Iodine by Reaction with a Fullerene Containing Carbon Compound and Insoluble Natural Matrix

The stability of the association of iodine with FCC and NOM products were studied. Product distributions for the various matrices under various reaction conditions were examined in order to maximize the binding of iodine. The recovery of the iodine from the sequestration matrices was also examined, along with the conversion of the iodine to matrices more suitable for geological storage and/or use as transmutation targets. The following are the specific research objectives and goals: Develop bench-scale experimental set-up and procedures for simulating plutonium extraction process (PUREX) head-end vapor phase. Develop experimental procedures for evaluating iodine sequestering methods using bench-scale procedures. Develop FCC bearing material as potential iodine sequestration matrix. Determine binding of iodine to FCC and NOM. Examine alternate iodine sequestration matrices using techniques developed for FCC and NOM studies. Examine the effect of reaction conditions on binding. Elucidate the nature of the reaction products (volatile, hydrophobic, soluble, insoluble). Develop methodology and host matrix for converting sequestered iodine to solid matrix for evaluation as transmutation target and/or disposal matrix. Examine recovery of iodine from sequestration matrices

Immobilization of Fission Iodine by Reaction with a Fullerene Containing Carbon Compound and Insoluble Natural Organic Matrix

The recovery of iodine released during the processing of used nuclear fuel poses a significant challenge to the transmutation of radioactive iodine. During the first year of this program we have examined the potential of Fullerene Containing Carbon compounds (FCC) developed by KRI, and natural organic matter (NOM) as sorbents for iodine released during the reprocessing of nuclear fuel. This work involved the development of bench-scale testing of the FCC and NOM material in a simulated process off-gas environment. During the first two quarters of this program we explored various analytical methods available for measurement of iodine, iodide, and iodate. We reproduced an analytical method proposed by Mishra et al., 2000 for measurement of trace levels of iodide and iodine in aqueous solution. Iodine or hypoiodic acid reacts with N,N-dimethylanaline to form p-iododimethylaniline. Iodide can be measured after selective oxidation of iodide with 2-iodosobenzoate to produce active iodine that is subsequently reacted with N,Ndimethylaniline. The product p-iodo-N,N-dimethylaniline can be quantified by GC/MS. This method gave excellent results in dilute aqueous solutions however; we did encounter some interference in the presence of NOM. The method should still be useful for quantifying low levels on iodine released by FCC or other sorbent materials

Simulation of Micro-Electronic FlowFET Systems

A microelectronic fluidic system has been investigated by modeling and 3D simulation of fluid flow controlled by an applied gate voltage. The simulations have helped to characterize a novel FlowFET (a fluidic Field Effect Transistor) device under fault-free conditions. The FlowFET operates by applying a voltage field from a gate electrode in the insulated side wall of a microchannel to modulate the ␣-potential at the shear plane [1]. The change in ␣-potential can be used to control both the magnitude and direction of the electroosmotic flow in the microchannel

Fair Value Accounting: A Historical Review Of The Most Controversial Accounting Issue In Decades

Historically, there have been many disputes in the area of corporate financial reporting.  However, one of the primary issues of disagreement between practitioners, regulators, and theoreticians is that of valuation of financial statement components.  The latest twist in the evolution of valuation is the push for (and against) the use of a fair value approach.  The purpose of this paper is to examine the history and evolution of how the most critical elements of an entity’s financial statements are valued.  We provide a history of valuation of financial statement components, and identify the issues involved.  Further, we examine the criticisms of actions taken by the regulatory bodies in their efforts to standardize and advance accounting practices.  Particularly, we focus on the evolution of fair value measurements.  Arguments both for and against the implementation of fair value accounting are provided