An Adaptive Characteristic-wise Reconstruction WENOZ scheme for Gas Dynamic Euler Equations

Due to its excellent shock-capturing capability and high resolution, the WENO scheme family has been widely used in varieties of compressive flow simulation. However, for problems containing strong shocks and contact discontinuities, such as the Lax shock tube problem, the WENO scheme still produces numerical oscillations. To avoid such numerical oscillations, the characteristic-wise construction method should be applied. Compared to component-wise reconstruction, characteristic-wise reconstruction leads to much more computational cost and thus is not suite for large scale simulation such as direct numeric simulation of turbulence. In this paper, an adaptive characteristic-wise reconstruction WENO scheme, i.e. the AdaWENO scheme, is proposed to improve the computational efficiency of the characteristic-wise reconstruction method. The new scheme performs characteristic-wise reconstruction near discontinuities while switching to component-wise reconstruction for smooth regions. Meanwhile, a new calculation strategy for the WENO smoothness indicators is implemented to reduce over-all computational cost. Several one dimensional and two dimensional numerical tests are performed to validate and evaluate the AdaWENO scheme. Numerical results show that AdaWENO maintains essentially non-oscillatory flow field near discontinuities as the characteristic-wise reconstruction method. Besieds, compared to the component-wise reconstruction, AdaWENO is about 40\% faster which indicates its excellent efficiency

Pressure-induced charge orders and their postulated coupling to magnetism in hexagonal multiferroic LuFe\u3csub\u3e2\u3c/sub\u3eO\u3csub\u3e4\u3c/sub\u3e

Hexagonal LuFe2O4 is a promising charge order (CO) driven multiferroic material with high charge and spin-ordering temperatures. The coexisting charge and spin orders on Fe3+/Fe2+ sites result in magnetoelectric behaviors, but the coupling mechanism between the charge and spin orders remains elusive. Here, by tuning external pressure, we reveal three charge-ordered phases with suggested correlation to magnetic orders in LuFe2O4: (i) a centrosymmetric incommensurate three-dimensional CO with ferrimagnetism, (ii) a non-centrosymmetric incommensurate quasi-two-dimensional CO with ferrimagnetism, and (iii) a centrosymmetric commensurate CO with antiferromagnetism. Experimental in situ single-crystal X-ray diffraction and X-ray magnetic circular dichroism measurements combined with density functional theory calculations suggest that the charge density redistribution caused by pressure-induced compression in the frustrated double-layer [Fe2O4] cluster is responsible for the correlated spin-charge phase transitions. The pressure-enhanced effective Coulomb interactions among Fe-Fe bonds drive the frustrated (1/3, 1/3) CO to a less frustrated (1/4, 1/4) CO, which induces the ferrimagnetic to antiferromagnetic transition. Our results not only elucidate the coupling mechanism among charge, spin, and lattice degrees of freedom in LuFe2O4, but also provide a new way to tune the spin-charge orders in a highly controlled manner

Whole-genome resequencing of 472 Vitis accessions for grapevine diversity and demographic history analyses

Despite the importance of grapevine cultivation in human history and the economic values of cultivar improvement, large-scale genomic variation data are lacking. Here the authors resequence 472 Vitis accessions and use the identified genetic variations for domestication history, demography, and GWAS analyses

The diploid genome sequence of an Asian individual

Here we present the first diploid genome sequence of an Asian individual. The genome was sequenced to 36-fold average coverage using massively parallel sequencing technology. We aligned the short reads onto the NCBI human reference genome to 99.97% coverage, and guided by the reference genome, we used uniquely mapped reads to assemble a high-quality consensus sequence for 92% of the Asian individual's genome. We identified approximately 3 million single-nucleotide polymorphisms (SNPs) inside this region, of which 13.6% were not in the dbSNP database. Genotyping analysis showed that SNP identification had high accuracy and consistency, indicating the high sequence quality of this assembly. We also carried out heterozygote phasing and haplotype prediction against HapMap CHB and JPT haplotypes (Chinese and Japanese, respectively), sequence comparison with the two available individual genomes (J. D. Watson and J. C. Venter), and structural variation identification. These variations were considered for their potential biological impact. Our sequence data and analyses demonstrate the potential usefulness of next-generation sequencing technologies for personal genomics

Big Data Extraction with Adaptive Wavelet Analysis

Nondestructive evaluation and sensing technology have been increasingly applied to characterize material properties and detect local damage in structures. More often than not, they generate images or data strings that are difficult to see any physical features without novel data extraction techniques. In the literature, popular data analysis techniques include Short-time Fourier Transform, Wavelet Transform, and Hilbert Transform for time efficiency and adaptive recognition. In this study, a new data analysis technique is proposed and developed by introducing an adaptive central frequency of the continuous Morlet wavelet transform so that both high frequency and time resolution can be maintained in a time-frequency window of interest. The new analysis technique is referred to as Adaptive Wavelet Analysis (AWA). This paper will be organized in several sections. In the first section, finite time-frequency resolution limitations in the traditional wavelet transform are introduced. Such limitations would greatly distort the transformed signals with a significant frequency variation with time. In the second section, Short Time Wavelet Transform (STWT), similar to Short Time Fourier Transform (STFT), is defined and developed to overcome such shortcoming of the traditional wavelet transform. In the third section, by utilizing the STWT and a time-variant central frequency of the Morlet wavelet, AWA can adapt the time-frequency resolution requirement to the signal variation over time. Finally, the advantage of the proposed AWA is demonstrated in Section 4 with a ground penetrating radar (GPR) image from a bridge deck, an analytical chirp signal with a large range sinusoidal frequency change over time, the train-induced acceleration responses of the Tsing-Ma Suspension Bridge in Hong Kong, China. The performance of the proposed AWA will be compared with the STFT and traditional wavelet transform

Demo: On the High Quality Sensor Placement for Structural Health Monitoring

Abstract—Sensor networks are widely used for structural health monitoring systems today. Existing studies on sensor systems from computer science community seldom take civil and structure factors into consideration. For example, the commonly adopted sensor placement schemes are still assumed to be random or on grids. We release an open source package SPEM, which, working as a black box, can evaluate the locations of sensor placement from the aspects of civil engineering. In this demo, we will first show how this package can be used by a few synthetic examples. We will show its indication for the designs of sensor networks to the computer science community. We will further illustrate SPEM with real structural data collected from our ongoing monitoring project of the Guangzhou New TV Tower. I

Fluorescent Probe-Based Fiber Optic Sensor for Real-Time Monitoring of Chloride Ions in Coastal Concrete Structures

Coastal concrete structures, such as cross-sea bridges and tunnels, are susceptible to the penetration of chloride ions, which can lead to the deterioration of the passive film on the rebar surface, consequently accelerating the corrosion process. Conventional methods for monitoring chloride ions typically require in situ drilling for sample collection, thereby compromising efficiency and accuracy. Additionally, real-time monitoring and early warning cannot be achieved. To address these challenges, this work introduces a fluorescent-probe-based fiber optic sensor for monitoring chloride levels in concrete structures. Quinine sulfate was chosen as the fluorescent material due to its exceptional sensitivity to chloride ions and its stability in concrete environments. The proposed sensor was manufactured using sol–gel and 3D-printing techniques. Tests were conducted using concrete simulation fluid and cement mortar specimens. The results demonstrate that the sensitivity of the proposed sensor is greater than 0.01 M, and its accuracy in penetration depth measurement is better than 3 mm. The findings confirm that the designed fiber optic sensor based on quinine sulfate enables real-time monitoring of chloride ions in concrete structures, offering high sensitivity (0.1% in concentration and 2.7 mm in terms of penetration depth), unique selectivity (as it is immune to other ions whose concentrations are 10 times higher than those of Cl−), and a compact size (10 × 20 mm). These attributes render it promising for practical engineering applications

Efficient implementation of high-order WENO schemes with sharing function for solving Euler equations

Due to the high-order accuracy and essentially non-oscillatory (ENO) property, the weighted ENO (WENO) schemes have a wide range of successful applications. The component-wise reconstruction WENO (CP WENO) scheme for fluxes or variables has simple formulations but it may produce numerical oscillations near discontinuities when solving the Euler equations. Although the characteristic-wise reconstruction WENO (CH WENO) scheme can reduce such oscillations, it involves too many characteristic projection operations. In this paper, first, we introduced a sharing function to indicate the discontinuities in the Euler equations and then constructed new adaptive characteristic-wise WENO (Ada-WENO) scheme and common-weights WENO (Co-WENO) scheme with this function. Several one and two dimensional problems are used to test the performances of Ada-WENO and Co-WENO. Numerical results show that, Ada-WENO can reduce the computational cost of CH WENO while maintaining its oscillation-free property since it only switches from CP WENO to CH WENO near discontinuities, and Co-WENO can reduce the cost and oscillations of CP WENO, but it may still generate few oscillations

Sustainable Urban Street Comprising Permeable Pavement and Bioretention Facilities: A Practice

Roadside bioretention and permeable pavements have proven effectiveness in rainwater filtration and waterlogging mitigation, but conventional street design approach could not accommodate their work in conjunction. In this research, possible roadside facilities allowing water transmission from permeable pavements and bioretention to the pipe system are proposed. Hydraulic properties of the comprised elements were analyzed, including rainfall intensity, permeable pavements, soil layers and pipe systems. A transformation method was formulated to obtain a successive time-intensity formula from conventional design parameters to describe the rainfall behavior, and therefore the water retention capacity of the bioretention could be considered. A test section of 1.6 km combining permeable pavements and roadside bioretention was constructed, and its hydraulic performance was predicted based on the proposed design method and Storm Water Management Model (SWMM). The research results suggest that the bioretention facilities and permeable pavements cooperate well in the test section. In a light rain event, the proposed street has favorable performance in rainwater collection and filtration. In a relatively intense rainstorm event, the street collects and filters water in the initial stage, but will have similar hydraulic performance to a conventional street once the retention facilities are saturated. Thus, no reduction in diameters of drainage pipes from conventional designs is suggested in similar projects