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We first analyzed GPS precipitable water vapor (GPS/PWV) available from a ground-based GPS observation network in Guangdong from 1 August 2009 to 27 August 2012 and then developed a method of quality control before GPS/PWV data is assimilated into the GRAPES 3DVAR system. This method can reject the outliers effectively. After establishing the criterion for quality control, we did three numerical experiments to investigate the impact on the precipitation forecast with and without the quality-controlled GPS/PWV data before they are assimilated into the system. In the numerical experiments, two precipitation cases (on 6 to 7 May, 2010 and 27 to 28 April, 2012 respectively) that occurred in the annually first raining season of Guangdong were selected. The results indicated that after quality control, only the GPS/PWV data that deviates little from the NCEP/PWV data can be assimilated into the system, has reasonable adjustment of the initial water vapor above Guangdong, and eventually improves the intensity and location of 24-h precipitation forecast significantly. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, a highly birefringent index-guiding photonic crystal fiber with low confinement loss is proposed by enlarging the central row of air holes in the structure. By employing the multipole method, properties of this structure, including the effective index, birefringence and confinement loss, are investigated. Simulation results indicate that high birefringence of 1.65×10−3 can be reached at the wavelength of 1.55μm, and a low confinement loss on the order of 10−6 dB/km can be achieved at the same wavelength. Moreover, the impacts of air hole sizes on birefringence and confinement loss are also analyzed in detail. [Copyright &y& Elsevier]

Highlights: [•] Highly birefringent PCFs with circular air holes in elliptical configuration are simulated. [•] High birefringence on the order of 10−3 is realized in both structures. [•] A low confinement loss on the order of 10−8 dB/m is achieved in one structure. [•] Impacts of elliptic ratio on birefringence and confinement loss are analyzed. [ABSTRACT FROM AUTHOR]

A mathematical model was developed in this paper to describe the nonylphenol (NP) accumulation in the effluent of a wastewater recycling system. The model quantitatively presented the relationships among the NP concentrations in the raw wastewater and the system effluent, the number of wastewater recycling cycles, the water recycling ratio, the system NP removal efficiency, and the NP accumulation factor. The mathematical model was then verified through experimental modeling of a wastewater recycling process, and it was indicated that the Pearson correlation coefficient between mathematical simulation and experimental modeling results was 0.652. The study results indicated that the NP accumulation factor of a wastewater recycling system would approach a constant for large number of wastewater recycling cycles given the wastewater recycling ratio and system NP removal efficiency. The results also revealed that the NP concentration in the effluent increased with the wastewater recycling ratio given the system NP removal efficiency, and the increase of NP removal efficiency would decrease the NP accumulation in the system effluent under a given wastewater recycling ratio condition. The model was then applied to compute the maximum wastewater recycling ratio, predict reclaimed water quality and direct the design and management of sewage recycling systems in China. [Copyright &y& Elsevier]

An innovative secondary circuit passive residual heat removal scheme, termed as Passive Accident Mitigation Scheme (PAMS), is investigated in our work. PAMS aims at removing core residual heat and ensuring reactor safety for Pressurized Water Reactor (PWR) Nuclear Power Plant (NPP), which consists of two parts: the first part is Passive Auxiliary Feedwater System (PAFS), and the other part is Passive Residual Heat Removal System (PRHRS). Shi et al. (2015) analyzed the PAMS operation characteristics under Station Blackout (SBO) accident using RELAP5. In order to assess the ability of PAMS, more analyses should be carried out. This paper takes the Westinghouse-designed Advanced Passive PWR (AP1000) as research object and proposes the simulation performance verification of PAMS under FLB accident with the help of RELAP5. Moreover, the comparative analysis is also conducted between PAMS and traditional secondary circuit PRHRS with different design capacities under FLB accident. Results show that: during the whole accident process, the key parameters’ performances of primary system could meet acceptance criteria requirements, which proves PAMS can cope with FLB accident; moreover, since only the PAMS train connected to intact circuit can operate to mitigate FLB accident, the analysis results prove that PAMS design satisfies single failure criterion; the primary system cooling process with PAMS operation is quite close to primary system cooling process with 4% of Full Power (FP) design capacity PRHRS operation, and both of them can remove core residual heat significantly under FLB accident. [ABSTRACT FROM AUTHOR]

We experimentally realized a planar acoustic superlens by a simple structure consisting of periodically arrayed rigid slabs. Based on the excitation of guided modes and the moderate amplification of the evanescent waves, we have broken the diffraction limit and obtained a subwavelength image with a half-power beamwidth of 0.07λ. All the experimental results are in good agreement with the theoretical simulations via finite difference time domain method. [ABSTRACT FROM AUTHOR]

The dynamic stress strain simulation is one of the several digital rock physics methods that calculate elastic property of digital rocks. Simulations for calculating P- and S-wave property of one digital rock includes one compressional simulation and three shear simulations. Moreover, the simulation frequency must be low enough to meet the long wavelength assumption. Hence, heavy computational burden is unavoidable. To improve the computational efficiency, in addition to parallel computation, one possible way is to optimize the boundary condition applied on the digital rocks. The idea is to integrate the four kinds of boundary condition which correspond to the four separated simulations in the existed method into one boundary condition, accordingly the number of simulation reduces to one. The computational efficiency of the new simulation method improves approximately four times, and the numerical accuracy is proved to be unaltered. [ABSTRACT FROM AUTHOR]