How does breakup influence the total fusion of 6,7^{6,7}Li at the Coulomb barrier?

Total (complete + incomplete) fusion excitation functions of $^{6,7}$Li on $^{59}$Co and $^{209}$Bi targets around the Coulomb barrier are obtained using a new continuum discretized coupled channel (CDCC) method of calculating fusion. The relative importance of breakup and bound-state structure effects on total fusion is particularly investigated. The effect of breakup on fusion can be observed in the total fusion excitation function. The breakup enhances the total fusion at energies just around the barrier, whereas it hardly affects the total fusion at energies well above the barrier. The difference between the experimental total fusion cross sections for $^{6,7}$Li on $^{59}$Co is notably caused by breakup, but this is not the case for the $^{209}$Bi target.Comment: 9 pages, 9 figures, Submitted to Phys. Rev.

Near-barrier Fusion Induced by Stable Weakly Bound and Exotic Halo Light Nuclei

The effect of breakup is investigated for the medium weight $^{6}$Li+$^{59}$Co system in the vicinity of the Coulomb barrier. The strong coupling of breakup/transfer channels to fusion is discussed within a comparison of predictions of the Continuum Discretized Coupled-Channels model which is also applied to $^{6}$He+$^{59}$Co a reaction induced by the borromean halo nucleus $^{6}$He.Comment: 6 pages, 3 figures. A talk given at the FUSION06: International Conference on Reaction Mechanisms and Nuclear Structure at the Coulomb barrier, March 19-23, 2006, San Servolo, Venezia, Ital

Relating breakup and incomplete fusion of weakly-bound nuclei through a classical trajectory model with stochastic breakup

A classical dynamical model that treats break-up stochastically is presented for low energy reactions of weakly-bound nuclei. The three-dimensional model allows a consistent calculation of breakup, incomplete and complete fusion cross sections. The model is assessed by comparing the breakup observables with CDCC quantum mechanical predictions, which are found to be in reasonable agreement. Through the model, it is demonstrated that the breakup probability of the projectile as a function of its distance from the target is of primary importance for understanding complete and incomplete fusion at energies near the Coulomb barrier.Comment: Accepted in Physical Review Letter

Beyond the Coherent Coupled Channels Description of Nuclear Fusion

New measurements of fusion cross sections at deep sub-barrier energies for the reactions 16O+204,208Pb show a steep but almost saturated logarithmic slope, unlike 64Ni-induced reactions. Coupled channels calculations cannot simultaneously reproduce these new data and above-barrier cross-sections with the same Woods-Saxon nuclear potential. It is argued that this highlights an inadequacy of the coherent coupled channels approach. It is proposed that a new approach explicitly including gradual decoherence is needed to allow a consistent description of nuclear fusion

Variational analysis for a generalized spiked harmonic oscillator

A variational analysis is presented for the generalized spiked harmonic oscillator Hamiltonian operator H, where H = -(d/dx)^2 + Bx^2+ A/x^2 + lambda/x^alpha, and alpha and lambda are real positive parameters. The formalism makes use of a basis provided by exact solutions of Schroedinger's equation for the Gol'dman and Krivchenkov Hamiltonian (alpha = 2), and the corresponding matrix elements that were previously found. For all the discrete eigenvalues the method provides bounds which improve as the dimension of the basis set is increased. Extension to the N-dimensional case in arbitrary angular-momentum subspaces is also presented. By minimizing over the free parameter A, we are able to reduce substantially the number of basis functions needed for a given accuracy.Comment: 15 pages, 1 figur

Heating ventilation and air-conditioned configurations for hotels an approach review for the design and exploitation

The tourism sector is one of the main worldwide economic sectors with sustained growth, demonstrating its strength and resilience. In this sector, energy uses have increased to ensure quality, guest comfort, and rate level requirements being a building with great energy consumption. Several factors influence and can produce a significant variation in hotel consumption even in facilities located in the same region; the difference in a four-star hotel can reach 114 kWh/m2 /year. This paper deals with related aspects such as hotel design, operation, type of service, occupancy patterns, operating point and efficiency of a heating, ventilation, and air conditioning (HVAC) system where 30 to 50% of the energy is consumed. Also, previous works based on the implementation of non-conventional energy resources such as photovoltaics projects to replace fuel dependence and high costs in electricity bills were reviewed. where there are savings of up to 30% in electricity and 60% in gas consumption. However, the initial capital investment and payback period are high and require new features to be considered in these facilities