A hybrid stabilization technique for simulating water wave - Structure interaction by incompressible Smoothed Particle Hydrodynamics (ISPH) method

The Smoothed Particle Hydrodynamics (SPH) method is emerging as a potential tool for studying water wave related problems, especially for violent free surface flow and large deformation problems. The incompressible SPH (ISPH) computations have been found not to be able to maintain the stability in certain situations and there exist some spurious oscillations in the pressure time history, which is similar to the weakly compressible SPH (WCSPH). One main cause of this problem is related to the non-uniform and clustered distribution of the moving particles. In order to improve the model performance, the paper proposed an efficient hybrid numerical technique aiming to correct the ill particle distributions. The correction approach is realized through the combination of particle shifting and pressure gradient improvement. The advantages of the proposed hybrid technique in improving ISPH calculations are demonstrated through several applications that include solitary wave impact on a slope or overtopping a seawall, and regular wave slamming on the subface of open-piled structure

Energy efficiency convergence across countries in the context of China's Belt and Road initiative

© 2018 Elsevier Ltd After China launched its “Belt and Road” (BR) initiative, the international community became concerned that it may worsen the environmental performance of the BR countries. Due to a lack of data for empirical testing, this paper addresses this concern through an indirect method and draws the implications of the potential impacts of China's BR initiative. This method empirically examines the effects of trade integration and regional cooperation, two major functions of the BR initiative, on energy efficiency (EE) convergence, a concept that describes the catching up process of EE across countries. A sample of 89 countries was selected to analyse the process of EE convergence from 2000 to 2014. The results indicate that although the gaps in EE among countries around the world become larger after 2010, regional cooperation may lead to a convergence process. It also finds that trade integration has a positive influence on convergence across the countries, especially among middle- and low-income countries. The results suggest that the BR initiative, through its roles in trade integration and regional cooperation, may promote EE convergence among countries. This is a desirable environmental outcome. This research also provides policy implications for both China and the other BR countries

Application of high-resolution melting for variant scanning in chloroplast gene atpB and atpB-rbcL intergenic spacer region of Crucifer species

High-resolution melting (HRM) analysis is a rapid and sensitive method for single nucleotide polymorphism (SNP) analysis. In this study, a novel HRM assay was carried out to detect SNPs in the chloroplast gene atpB which encodes the beta subunit of the ATP synthase and atpB upstream intergenic region. The polymorphisms of the two fragments in intertribal samples from the Cruciferae family and within the species of Brassica napus were detected. Based on this results, we found that HRM were able to determine over 90% of the variants which included single or multiple variants and insertion-deletion polymorphisms (INDELs) and rendered possible genotyping of more closely spaced polymorphisms, although there were several false positives (FPs) and misclassification. Six haplotypes were identified in the intertribal materials. The analysis of 90 B. napus found five variation types and the variations were all located in the intergenic region. In conclusion, HRM analysis is a closed tube assay that is easy to perform and is a more effective approach to identify variant of chloroplast genes. This study will facilitate further functional investigations into the role of chloroplast genes in photosynthesis, phylogeny and molecular evolution.Key words: atpB gene, chloroplast genome, crucifer, high-resolution melt curve analysis, SNP, INDEL

Phonotactic steering and representation of directional information in the ascending auditory pathway of a cricket.

Directional hearing is crucial for animals depending on acoustic signals to locate a mate. We focused on crickets to explore the reliability of directional information forwarded to the brain by the ascending auditory interneuron AN1, which is crucial for phonotactic behavior. We presented calling song from -45° to +45° in steps of 3° and compared the phonotactic steering of females walking on a trackball with the directional responses of AN1. Forty percent of females showed good steering behavior and changed their walking direction when the speaker passed the body's longitudinal axis. The bilateral latency difference between right and left AN1 responses was small and may not be reliable for auditory steering. In respect to spike count, all AN1 recordings presented significant bilateral differences for angles larger than ±18°, yet 35% showed a mean significant difference of 1-3 action potentials per chirp when the frontal stimulus deviated by 3° from their length axis. For small angles, some females had a very similar AN1 activity forwarded to the brain, but the accuracy of their steering behavior was substantially different. Our results indicate a correlation between directional steering and the response strength of AN1, especially for large angles. The reliable steering of animals at small angles would have to be based on small bilateral differences of AN1 activity, if AN1 is the only source providing directional information. We discuss whether such bilateral response difference at small angles can provide a reliable measure to generate auditory steering commands descending from the brain, as pattern recognition is intensity independent.NEW & NOTEWORTHY The ascending auditory interneuron AN1 has been implicated in cricket auditory steering, but at small acoustic stimulation angles, it does not provide reliable directional information. We conclude that either the small bilateral auditory activity differences of the AN1 neurons are enhanced to generate reliable descending steering commands or, more likely, directional auditory steering is mediated via a thoracic pathway, as indicated by the reactive steering hypothesis

Effects of the combination of levonorgestrel and quinestrol on reproductive hormone levels and their receptor expression in female Mongolian gerbils (Meriones unguiculatus)

Lv, X., Guo, Y., Shi, D

Optimal manufacturing/remanufacturing policies with fixed investment for the underdeveloped remanufacturing system

© 2017, Strojarski Facultet. All rights reserved. In an underdeveloped remanufacturing system, poor infrastructure and low technical level impede further development of remanufacturing. To overcome this obstacle, a huge amount of fixed investment is required to improve the remanufacturing system. However, this investment inevitably influences the manufacturer’s manufacturing/remanufacturing decision-making economically. The relationship between fixed investment and recycling ratio was investigated, and the two- and multi-period manufacturing/remanufacturing mixed optimization models were developed. Based on the Karush-Kuhn-Tucker (KKT) conditions, the optimal manufacturing/remanufacturing and fixed investment policies were obtained in closed-form expressions. Moreover, the influences of the fixed investment were analysed. Results show that the optimal policies are significantly influenced by the degree of underdevelopment of the remanufacturing system. When the remanufacturing system is underdeveloped, the manufacturer shows a lack of enthusiasm in remanufacturing, thereby resulting in the decrease of the investment and the recycling ratio. The manufacturer raises the sale price to alleviate the loss caused by fixed investment, but the total manufacturing quantity and profit decrease. In the multi-period case, the manufacturer gradually increases the investment for continuously improving the remanufacturing system to increase the recycling ratio and obtain additional profits from remanufacturing. The proposed models can effectively provide the reference for determining the reasonable manufacturing/remanufacturing and fixed investment policies in the underdeveloped remanufacturing system

An improved solid boundary treatment for wave-float interactions using ISPH method

The Smoothed Particle Hydrodynamics (SPH) method has proved to have great potentials in dealing with the wave-structure interactions. Compared with the Weakly Compressible SPH (WCSPH) method, the ISPH approach solves the pressure by using the pressure Poisson equation rather than the equation of state. This could provide a more stable and accurate pressure field that is important in the study of wave-structure interactions. This paper improves the solid boundary treatment of ISPH by using a high accuracy Simplified Finite Difference Interpolation (SFDI) scheme for the 2D wave-structure coupling problems, especially for free-moving structure. The proposed method is referred as the ISPH_BS. The model improvement is demonstrated by the documented benchmark tests and laboratory experiment covering various wave-structure interaction applications

Differential Evolution-based 3D Directional Wireless Sensor Network Deployment Optimization

Wireless sensor networks (WSNs) are applied more and more widely in real life. In actual scenarios, 3D directional wireless sensors (DWSs) are constantly employed, thus, research on the real-time deployment optimization problem of 3D directional wireless sensor networks (DWSNs) based on terrain big data has more practical significance. Based on this, we study the deployment optimization problem of DWSNs in the 3D terrain through comprehensive consideration of coverage, lifetime, connectivity of sensor nodes, connectivity of cluster headers and reliability of DWSNs. We propose a modified differential evolution (DE) algorithm by adopting CR-sort and polynomial-based mutation on the basis of the cooperative coevolutionary (CC) framework, and apply it to address deployment problem of 3D DWSNs. In addition, to reduce computation time, we realize implementation of message passing interface (MPI) parallelism. As is revealed by the experimentation results, the modified algorithm proposed in this paper achieves satisfying performance with respect to either optimization results or operation time