Nonlinear fi nite element analysis of high-strength concrete columns and experimental verification

This paper describes a nonlinear finite element （FE） analysis of high strength concrete （HSC） columns, and verifies the results through laboratory experiments. First, a cyclically lateral loading test on nine cantilever column specimens of HSC is described and a numerical simulation is presented to verify the adopted FE models. Next, based on the FE model for specimen No.6, numerical simulations for 70 cases, in which different concrete strengths, stirrup ratios and axial load ratios are considered, are presented to explore the effect of these parameters on the behavior of the HSC columns, and to check the rationality of requirements for these columns specified in the China Code for Seismic Design of Buildings （GB 50011- 2001）. In addition, three cases with different stirrup strengths are analyzed to investigate their effect on the behavior of HSC columns. Finally, based on the numerical results some conclusions are presented.

LOW-COMPLEXITY JOINT BEAMFORMING AND POWER ALLOCA-TION FOR SINR BALANCING IN COGNITIVE RADIO NETWORKS

We consider the Signal-to-Interference plus Noise Ratio(SINR) balancing problem in-volving joint beamfoming and power allocation in the Cognitive Radio(CR) network,wherein the Single-Input Multi-Output Multiple Access Channels(SIMO-MAC) are assumed.Subject to two sets of constraints:the interference temperature constraints of Primary Users(PUs) and the peak power constraints of Cognitive Users(CUs),a low-complexity joint beamforming and power allocation algo-rithm called Semi-Decoupled Multi-Constraint Power Allocation with Constraints Preselection(SDMCPA-CP) for SINR balancing is proposed.Compared with the existing algorithm,the proposed SDMCPA-CP can reduce the number of matrix inversions and matrix eigen decompositions signifi-cantly,especially when large numbers of PUs and CUs are active,while still providing the optimal balanced SINR level for all the CUs.

Determination of crop and soil evaporation coefficients for estimating evapotranspiration in a paddy field

Accurate estimation of evapotranspiration is important in efficient water management for improving water use efficiency.In order to obtain evapotranspiration and evaporation beneath the canopy using the Food and Agriculture Organization(FAO)method,pan evaporation was used instead of reference evapotranspiration calculated by the Penman-Monteith equation with detailed meteorological data.The total crop coefficient and soil evaporation coefficient were determined using actual measured daytime evapotranspiration and evaporation by the Bowen ratio energy balance and lysimeter,respectively,in a rice paddy field in Japan.The average evapotranspiration was 5.3 mm/d,4.4 mm/d,7.4 mm/d and 6.3 mm/d and crop coefficient was 0.79,1.18,1.01 and 0.86 for the initial stage,development stage,middle-season stage and late-season stage,respectively.The evaporation was low and almost constant with an average value around 0.77 mm/d when the leaf area index(LAI)reached 3.The proposed average crop coefficients for different growing stages were applied to estimate daytime evapotranspiration and found suitable.A simple soil water evaporation coefficient model was developed using leaf area index for practical use and it was found that it could accurately estimate evaporation.

SURFACE IMBALANCE ENERGY CALCULATED AND ANALYZED WITH THE DATA OF EBEX-2000

Mainly.three methods have been developed to calculate turbulence heat flux.They are eddy covariance method,Bowen ratio/energy balance method and aerodynamic method.In this paper, all the three methods have been used to calculate sensible heat flux,latent heat flux and imbalance energy near the surface with the experiment data of EBEX-2000.Then comparisons of the three methods and some possible explanations of the surface imbalance energy are given.