9,274 research outputs found
Anatomy of decays and effects of next-to-leading order contributions in the perturbative QCD factorization approach
In this paper, we will make systematic calculations for the branching ratios
and the CP-violating asymmetries of the twenty one decays
by employing the perturbative QCD (PQCD) factorization approach. Besides the
full leading-order (LO) contributions, all currently known next-to-leading
order (NLO) contributions are taken into account. We found numerically that:
(a) the NLO contributions can provide enhancement to the LO PQCD
predictions for and , or a reduction to
\calb(\bar{B}_s^0 \to \pi^{-} K^{*+}), and we confirmed that the inclusion of
the known NLO contributions can improve significantly the agreement between the
theory and those currently available experimental measurements, (b) the total
effects on the PQCD predictions for the relevant transition form
factors after the inclusion of the NLO twist-2 and twist-3 contributions is
generally small in magnitude: less than enhancement respect to the
leading order result, (c) for the "tree" dominated decay and the "color-suppressed-tree" decay ,
the big difference between the PQCD predictions for their branching ratios are
induced by different topological structure and by interference effects among
the decay amplitude and : constructive for the
first decay but destructive for the second one, and (d) for \bar{B}_s^0 \to
V(\eta, \etar) decays, the complex pattern of the PQCD predictions for their
branching ratios can be understood by rather different topological structures
and the interference effects between the decay amplitude \cala(V\eta_q) and
\cala(V\eta_s) due to the \eta-\etar mixing.Comment: 18 pages, 2 figures, 3 tables. Some modifications of the text.
Several new references are adde
A framework for characterising energy consumption of machining manufacturing systems
Energy consumption in machining manufacturing systems is increasingly of interest due to concern for global climate change and manufacturing sustainability. To utilise energy more effectively, it is paramount to understand and characterise the energy consumption of machining manufacturing systems. To this end, a framework to analyse energy consumption characteristics in machining manufacturing systems from a holistic point of view is proposed in this paper. Taking into account the complexity of energy consumption in machining manufacturing systems, energy flow is described in terms of three layers of machining manufacturing systems including machine tool layer, task layer and auxiliary production layer. Furthermore, the energy consumption of machining manufacturing systems is modelled in the spatial and temporal dimensions, respectively, in order to quantitatively characterise the energy flow. The application of the proposed modelling framework is demonstrated by employing a comprehensive analysis of energy consumption for a real-world machining workshop. The characteristics of energy consumption for machine tool layer, task layer and auxiliary production layer are, respectively, obtained using quantitative models in the spatial and temporal dimensions, which provides a valuable insight into energy consumption to support the exploration of energy-saving potentials for the machining manufacturing systems
Research on Cascading Use of Waste Heat Technical Program in Heavy Oil Exploitation by SAGD Technology
AbstractIn Du 84 block Shu 1 area in Liaohe oilfield where used SAGD technology to exploit heavy oil, the temperature of wellhead produced fluid can reach up to 170-180Β°C, In view of this problem of wasting large amount of thermal energy, this paper proposes a set of technical program of cascading use of waste heat with the combination of generation of electrical energy and heating. Meanwhile, the generating capacity and heating area of the program as well as its economic efficiency are also calculated and analyzed. In addition, the parameters of generating system's condenser are optimized by taking the annual total cost of the condenser as the objective function and using majorized function fminsearch in MATLAB software, and the most superior technical parameters are determined. The result can offer some reference in using of waste heat in practical project
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