Stellar reaction rate for (22)Mg + p -> (23)Al from the asymptotic normalization coefficient in the mirror nuclear system (22)Ne + n -> (23)Ne

Journals published by the American Physical Society can be found at http://publish.aps.org/The production of (22)Na in ONe novae can be influenced by the (22)Mg(p,gamma)(23)Al reaction. To investigate this reaction rate at stellar energies, we have determined the asymptotic normalization coefficient (ANC) for (22)Mg + p -> (23)Al through measurements of the ANCs in the mirror nuclear system (22)Ne + n -> (23)Ne. The peripheral neutron-transfer reactions (13)C((12)C, (13)C)(12)C and (13)C((22)Ne, (23)Ne)(12)C were studied. The identical entrance and exit channels of the first reaction make it possible to extract independently the ground-state ANC in (13)C. Our experiment gives C(p1/2)(2) ((13)C) = 2.24 +/- 0.11 fm(-1), which agrees with the value obtained from several previous measurements. The weighted average for all the obtained C(p1/2)(2) is 2.31 +/- 0.08 fm(-1). This value is adopted to be used in obtaining the ANCs in 23Ne. The differential cross sections for the reaction (13)C((22)Ne, (23)Ne) (12)C leading to the J(pi) = 5/2(+) and 1/2(+) states in (23)Ne have been measured at 12 MeV/u. Optical model parameters for use in the DWBA calculations were obtained from measurements of the elastic scatterings (22)Ne + (13)C and (22)Ne + (12)C. The extracted ANC for the ground state in (23)Ne, C(d5/2)(2) = 0.86 +/- 0.08 +/- 0.12 fm(-1), is converted to its corresponding value in (23)Al using mirror symmetry to give C(d5/2)(2) ((23)Al) = (4.63 +/- 0.77) x 10(3) fm(-1). The astrophysical S factor S(0) for the (22)Mg(p, gamma) reactionwas determined to be 0.96 +/- 0.11 keVb. The consequences for nuclear astrophysics are discussed

Valorisation of Biowastes for the Production of Green Materials Using Chemical Methods

With crude oil reserves dwindling, the hunt for a sustainable alternative feedstock for fuels and materials for our society continues to expand. The biorefinery concept has enjoyed both a surge in popularity and also vocal opposition to the idea of diverting food-grade land and crops for this purpose. The idea of using the inevitable wastes arising from biomass processing, particularly farming and food production, is, therefore, gaining more attention as the feedstock for the biorefinery. For the three main components of biomass—carbohydrates, lipids, and proteins—there are long-established processes for using some of these by-products. However, the recent advances in chemical technologies are expanding both the feedstocks available for processing and the products that be obtained. Herein, this review presents some of the more recent developments in processing these molecules for green materials, as well as case studies that bring these technologies and materials together into final products for applied usage

Chemical model of reaction cascades induced by activated enzymes or catalysts. Two-step cascades in visual transduction.

A dissipative system is approximated by a nonlinear rate equation: Z congruent to K1Z - K2Z3 (K2 greater than 0), in which the right side is derived from -delta G/delta Z of Taylor's series of the thermodynamic potential given by Gibbs' function G(Tc, Pc) (Z) at about the critical point C(Tc, Pc) of the control variables (parameters) T and P. The stability or instability of the system is treated by the changes in the control parameters. In the case that T not equal to P not equal to 0 in the steady state, Z = 0, and T and P pass the point C, K1 becomes negative. By this change, the G function is convex at Z = 0 and each product is created rapidly with concentration or number of the molecules Z = ([K1]/K2)1/2. This dynamic theory is applied to enzyme cascades. Based on cyclic GMP (cGMP) hypothesis in visual transduction, the cascade hydrolysis of cGMP of vertebrates is analyzed by dividing it into two-step reaction cascades: The initial process is that metarhodopsin II catalyzes the exchange of GDP for GTP by transducin (Gtd) and that GTP-Gtd complex is hydrolyzed to GDP-Gtd complex. In the following cascade cGMP is hydrolyzed with amplification of phosphodiesterase (PDE) activated by the removal of the small inhibitory subunit. The quantity of the hydrolysis of cGMP is estimated as approximately 5 x 10(4-5) molecules per photolyzed rhodopsin semiempirically, and this coincides well with experiments