Wind Structure in Winter Storms

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/77570/1/AIAA-511-343.pd

Nonequilibrium thermodynamical model for spent fuel dissolution rate

A non-equilibrium thermodynamic model is developed for the dissolution response of uranium oxide spent fuels waste forms. The objective is to derive function forms for the dissolution rate that are consistent with quasi-static, irreversible thermodynamic processes. These function forms contain thermodynamic chemical potentials of both the solid (spent fuels) and the solution (water chemistries) along with a set of coefficients and parameters that can be evaluated by numerical regression of dissolution test data. Currently, detailed knowledge is not available for the atomic (mechanistic) steps and the sequence of chemical/electro-chemical reaction steps to describe the dissolution process over the range of spent fuel inventory, potential water chemistries, and temperatures. The existing approach is obtaining an experimental data base of dissolution rates for a subset of spent fuels over a range of controlled, aggressive water chemistries and temperatures. With a numerical regression algorithm, these data are used to evaluate empirical parameters in a rate law. The function form of this rate law is a product polynomial of the bulk water chemistry concentrations and temperature. In its present form, this function form does not have an explicit thermodynamic dependence on the uranium oxide waste form. In addition, the use of bulk concentrations in the function form for the regression analysis of the dissolution data would not explicitly account for a dependence from possible surface to bulk concentration differences due to surface adsorption and dipole layers. The following thermodynamic model uses analysis methods and physical concepts taken primarily from classical mechanics, colloidal foundations, thermodynamics, electro-chemistry, and geochemistry

International Society of Sports Nutrition position stand: beta-alanine

Position statement: The International Society of Sports Nutrition (ISSN) provides an objective and critical review of the mechanisms and use of beta-alanine supplementation. Based on the current available literature, the conclusions of the ISSN are as follows: 1) Four weeks of beta-alanine supplementation (4–6 g daily) significantly augments muscle carnosine concentrations, thereby acting as an intracellular pH buffer; 2) Beta-alanine supplementation currently appears to be safe in healthy populations at recommended doses; 3) The only reported side effect is paraesthesia (tingling), but studies indicate this can be attenuated by using divided lower doses (1.6 g) or using a sustained-release formula; 4) Daily supplementation with 4 to 6 g of beta-alanine for at least 2 to 4 weeks has been shown to improve exercise performance, with more pronounced effects in open end-point tasks/time trials lasting 1 to 4 min in duration; 5) Beta-alanine attenuates neuromuscular fatigue, particularly in older subjects, and preliminary evidence indicates that beta-alanine may improve tactical performance; 6) Combining beta-alanine with other single or multi-ingredient supplements may be advantageous when supplementation of beta-alanine is high enough (4–6 g daily) and long enough (minimum 4 weeks); 7) More research is needed to determine the effects of beta-alanine on strength, endurance performance beyond 25 min in duration, and other health-related benefits associated with carnosine