Sensitivity of Pion versus Parton-Jet Nuclear Modification Factors to the Path-Length Dependence of Jet-Energy Loss at RHIC and LHC

We compare the jet-path length and beam-energy dependence of the pion nuclear modification factor and a patton-jet nuclear modification factor at RHIC and LHC, and contrast the predictions based on a linear pQCD and a highly non-linear hybrid AdS holographic model of jet-energy loss. It is found that both models require a reduction of the jet-medium coupling from RHIC to LHC to account for the measured pion nuclear modification factor. In the case of the parton-jet nuclear modification factor, however, which serves as a lower bound for the LO jet nuclear modification factor of reconstructed jets, the extracted data can be characterized without a reduced jet-medium coupling at LHC energies. It is concluded that when the reconstructed jets are sensitive to both quarks and gluons and thus provide more information than the pion nuclear modification factor, their information regarding the jet-medium coupling is limited due to the superposition with NLO and medium effects. Hence, a detailed description of the underlying physics requires both the leading hadron and the reconstructed jet nuclear modification factor. Unfortunately, the results for both the pion and the parton-jet nuclear modification factor are insensitive to the jet-path dependence of the models considered.

Modeling N_2O Emissions from Agricultural Fields in Southeast China

DNDC, a rainfall-driven and process-oriented model of soil carbon and nitrogenbiogeochemistry, is applied t0 simulate the nitrous oxide emissions from agricultural ecosystem inSoutheast China. We simulated the soil N2O emission during a whole rice-wheat rotation cycle(from Nov. 1, 1996 to Oct. 31, 1997) under three different conditions, which are A) no fertilizer, B)both chemical fertilizer and manure and, C) chemical fertiliser only. The processes ofN2O emission were discussed in detail by comparing the model outputs with the results from fieldmeasurement. The comparison shows that the model is good at simulating most of theNzO emission pulses and trends. Although the simulated N2O emission fluxes are generally lessthan the measured ones, the model outputs during the dryland period, especially during the wheatreviving and maturing stages in spring, are much better than those during the paddy field period.Some sensitive experiments were made by simulating the N2O emissions in spring, when there is asmallest gap between the simulated fluxes and the measured ones. Meanwhile, the effects of someimportant regulating factors, such as the rainfall N deposition by rainfall, temperature, tillage, nitrogen fertilizer and manure application on N2O emission during this period were analyzed. Fromthe analysis, we draw a conclusion that soil moisture and fertilization are the most important regulating factors while the N2O emission is sensitive to some other factors, such as temperature, manure, tillage and the wet deposition of atmospheric nitrate.

Photoreduction of CO_(2) in the presence of CH_(4) over g-C_(3)N_(4) modified with TiO_(2) nanoparticles at room temperature

CO_(2)reduction under simulated sunlight over photocatalysts has become an attractive researcher area recently.In this work,carbon nitride compounds modified by TiO_(2)nanoparticles(TNPs)have been used for the photoreduction of CO_(2)in the presence of CH_(4)at room temperature.Briefly,a series of noble-metal-free TNP-graphitic-carbon nitride(g-C_(3)N_(4),also abbreviated CN)photocatalysts with different TNPs loadings and calcination temperatures have been synthesized by a wet-chemical method.The characterization results of XRD,FTIR,SEM,TEM,BET,XPS,CO_(2)Adsorption,UV-vis,and PL demonstrate that the BET surface area and CO_(2)adsorption capacity have been improved after the calcination.Besides,the g-C_(3)N_(4)has been successfully coupled with the TNPs and a heterojunction has formed at their interface.These characters contribute to increase the photocatalytic activity of TNPs-CN toward reducing CO_(2)in the presence of CH_(4),and its'performance is better than bare g-C_(3)N_(4),Titania(P_(25))-CN,MgO-CN,or Cu_(2)O-CN.Orthogonal experiments are then carried out to investigate the sensitivity factors and optimum conditions.The sensitivity results show that the reaction pressure makes little difference on the photocatalysis results,which verifies the photoinduced CO_(2)-CH_(4)reaction has a tiny change in gas volume.In addition,under the optimum conditions,the turnover frequency(TOF)of CO after 4 h reaction can reach 9.98μmol g-cat.^(-1)h^(-1),and traces of ethane and ethylene have been detected during the reactions.In addition,surface acetate and carbonaceous deposit are found on the(20)TNPs-CN/450 surface after continuous 24 h irradiation under the optimum conditions,which resulting in the inactivation of the catalyst.Finally,possible reaction mechanisms have been proposed based on the results.

The Phenomenal Alleviation of Transmission Congestion by Optimally Placed Multiple Distributed Generators Using PSO

In the current electricity paradigm, the rapid elevation of demands in industrial sector and the process of restructuring are the main causes for the overuse of transmission systems. Hence, the evolution of novel technology is the ultimate need to avoid the damages in the available transmission systems. An appreciable volume of renewable energy sources is used to produce electric power, after the implementation of deregulation in power system. Even though, they are intended to improve the reliability of power system, the unpredictable outages of generators or transmission lines, an impulsive increase in demand and the sudden failures of vital equipment cause transmission congestion in one or some transmission lines. Generation rescheduling and load shedding can be used to alleviate congestion, but some cases require quite few improved methods. With the extensive application of Distributed Generation (DG), congestion management is also performed by the optimal placement of DGs. Therefore, this research employs a Line Flow Sensitivity Factor (LFSF) and Particle Swarm Optimization (PSO) for the determination of optimal location and size of multiple DG units, respectively. This proposed problem is formulated to minimize the total system losses and real power flow performance index. This approach is experimented in modified IEEE-30 bus test system. The results of N-1 contingency analysis with DG units prove the competence of this proposed approach, since the total numbers of congested lines get reduced from 15 to 2. Hence, the results show that the proposed approach is robust and simple in alleviating transmission congestion by the optimal placement and sizing of multiple DG units.

Reliable buffered clock tree routing algorithm with process variation tolerance

When IC technology is scaled into the very deep sub-micron regime, the optical proximity effects （OPE） turn into noticeable in optical lithography. Consequently, clock skew becomes more and more susceptible to process variations, such as OPE. In this paper, we propose a new buffered clock tree routing algorithm to prevent the influence of OPE and process variations to clock skew. Based on the concept of BSF （branch sensitivity factor）, our algorithm manages to reduce the skew sensitivity of the clock tree in the topology generation. The worst case skew due to the wire width change has been estimated, and proper buffers are inserted to avoid large capacitance load. Experimental results show that our algorithm can produce a more reliable, processinsensitive clock tree, and control clock skews in their permissible range evidently.