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1. chinaXiv:201804.00310 [pdf]

Analysis of the Hydroelastic Performance of Very Large Floating Structures Based on Multi-Modules Beam Theory

Xu, Jin; Sun, Yonggang; Li, Zhifu; Zhang, Xiantao; Lu, Da
Comment:本文发表在《Mathematical Problems in Engineering》
Subjects: Traffic and Transportation Engineering >> Ship Engineering

The hydroelastic behavior of very large floating structures (VLFSs) is investigated based on the proposed multi-modules beam theory (MBT). To carry out the analysis, the VLFS is first divided into multiple sub-modules that are connected through their gravity center by a spatial beam with specific stiffness. The external force exerted on the sub-modules includes the wave hydrodynamic force as well as the beam bending force due to the relative displacements of different sub-modules. The wave hydrodynamic force is computed based on three-dimensional incompressible velocity potential theory, and the boundary element method with the free surface Green function as the integral kernel is adopted to numerically find the solution. The beam bending force is expressed in the form of a stiffness matrix. The coupled motion equation is established according to the continuous conditions of the displacement and force. The motion response defined at the gravity center of the sub-modules is solved by the multi-body hydrodynamic control equations, then both the displacement and the structure bending moment of the VLFS are determined from the stiffness matrix equations. To account for the moving point mass effects, the proposed method is extended to the time domain based on impulse response function (IRF) theory. The accuracy of the proposed method is verified by comparison with existing results. Detailed results through the displacement and bending moment of the VLFS are provided to show the influence of the number of the sub-modules, and the influence of the moving point mass.

submitted time 2018-03-30 Hits3955Downloads2032 Comment 0

2. chinaXiv:201706.00364 [pdf]

Hydrodynamic analysis of multi-body floating system in waves: from rigid to flexible structures

Zhang Xiantao; Lu Da; Sun Yonggang; Gao Yun
Subjects: Physics >> General Physics: Statistical and Quantum Mechanics, Quantum Information, etc.

The hydrodynamic problem for multi-body systems in waves has complexity in both wave structure interaction and coupled dynamics with interconnection. A consistent approach is developed for calculating the dynamic response of multi-body floating systems. This method is based on multi-rigid-body hydrodynamics and Euler-beam bending theory and can be used to deal with rigid or flexible multi-body floating systems in both frequency and time domain. Within the framework of this consistent approach, a stiffness approximation method is proposed to calculate the natural frequency and corresponding oscillation mode of a hinged multi-module structure. This is significant for both traditional multi-body floating system (for the purpose of structural safety) and wave energy converters (for the purpose of power efficiency).

submitted time 2017-06-09 Hits15095Downloads2082 Comment 0

3. chinaXiv:201609.01022 [pdf]

Versatile Directional Searches for Gravitational Waves with Pulsar Timing Arrays

D. R. Madison(1; 2); X.-J. Zhu(3; 4); G. Hobbs; W. Coles; R. M. Shannon(4; 6); J. Wang; C. Tiburzi(8; 9; 10; 11); R. N. Manchester; M. Bailes; N. D. R. Bhat; S. Burke-Spolaor; S.Dai; J. Dempsey; M. Keith
Subjects: Physics >> Nuclear Physics

By regularly monitoring the most stable millisecond pulsars over many years, pulsar timing arrays (PTAs) are positioned to detect and study correlations in the timing behaviour of those pulsars. Gravitational waves (GWs) from supermassive black hole binaries (SMBHBs) are an exciting potentially detectable source of such correlations. We describe a straight-forward technique by which a PTA can be "phased-up" to form time series of the two polarisation modes of GWs coming from a particular direction of the sky. Our technique requires no assumptions regarding the time-domain behaviour of a GW signal. This method has already been used to place stringent bounds on GWs from individual SMBHBs in circular orbits. Here, we describe the methodology and demonstrate the versatility of the technique in searches for a wide variety of GW signals including bursts with unmodeled waveforms. Using the first six years of data from the Parkes Pulsar Timing Array, we conduct an all-sky search for a detectable excess of GW power from any direction. For the lines of sight to several nearby massive galaxy clusters, we carry out a more detailed search for GW bursts with memory, which are distinct signatures of SMBHB mergers. In all cases, we find that the data are consistent with noise.

submitted time 2016-09-14 Hits1163Downloads638 Comment 0

4. chinaXiv:201605.00479 [pdf]

Genome‐wide dissection of AP2/ERF and HSP90 gene families in five legumes and expression profiles in chickpea and pigeonpea

Gaurav Agarwal; Vanika Garg; Himabindu Kudapa; Dadakhalandar Doddamani; Lekha T. Pazhamala; Aamir W. Khan; Mahendar Thudi; Suk-Ha Lee; Rajeev K. Varshney
Subjects: Biology >> Botany >> Plant cytology, plant genetics & plant morphology

APETALA2/ethylene response factor (AP2/ERF) and heat-shock protein 90 (HSP90) are two significant classes of transcription factor and molecular chaperone proteins which are known to be implicated under abiotic and biotic stresses. Comprehensive survey identified a total of 147 AP2/ERF genes in chickpea, 176 in pigeonpea, 131 in Medicago, 179 in common bean and 140 in Lotus, whereas the number of HSP90 genes ranged from 5 to 7 in five legumes. Sequence alignment and phylogenetic analyses distinguished AP2, ERF, DREB, RAV and soloist proteins, while HSP90 proteins segregated on the basis of their cellular localization. Deeper insights into the gene structure allowed ERF proteins to be classified into AP2s based on DNA-binding domains, intron arrangements and phylogenetic grouping. RNA-seq and quantitative real-time PCR (qRT-PCR) analyses in heat-stressed chickpea as well as Fusarium wilt (FW)- and sterility mosaic disease (SMD)-stressed pigeonpea provided insights into the modus operandi of AP2/ERF and HSP90 genes. This study identified potential candidate genes in response to heat stress in chickpea while for FW and SMD stresses in pigeonpea. For instance, two DREB genes (Ca_02170 and Ca_16631) and three HSP90 genes (Ca_23016, Ca_09743 and Ca_25602) in chickpea can be targeted as potential candidate genes. Similarly, in pigeonpea, a HSP90 gene, C.cajan_27949, was highly responsive to SMD in the resistant genotype ICPL 20096, can be recommended for further functional validation. Also, two DREB genes, C.cajan_41905 and C.cajan_41951, were identified as leads for further investigation in response to FW stress in pigeonpea.

submitted time 2016-05-04 Hits2770Downloads1627 Comment 0

5. chinaXiv:201605.00474 [pdf]

BioNano genome mapping of individual chromosomes supports physical mapping and sequence assembly in complex plant genomes

Helena Sta?ková; Alex R. Hastie; Saki Chan; Jan Vrána; Zuzana Tulpová; Marie Kubaláková; Paul Visendi; Satomi Hayashi; Mingcheng Luo; Jacqueline Batley; David Edwards; Jaroslav Dole?el; Hana ?imková
Subjects: Biology >> Botany >> Plant cytology, plant genetics & plant morphology

The assembly of a reference genome sequence of bread wheat is challenging due to its specific features such as the genome size of 17?Gbp, polyploid nature and prevalence of repetitive sequences. BAC-by-BAC sequencing based on chromosomal physical maps, adopted by the International Wheat Genome Sequencing Consortium as the key strategy, reduces problems caused by the genome complexity and polyploidy, but the repeat content still hampers the sequence assembly. Availability of a high-resolution genomic map to guide sequence scaffolding and validate physical map and sequence assemblies would be highly beneficial to obtaining an accurate and complete genome sequence. Here, we chose the short arm of chromosome 7D (7DS) as a model to demonstrate for the first time that it is possible to couple chromosome flow sorting with genome mapping in nanochannel arrays and create a de novo genome map of a wheat chromosome. We constructed a high-resolution chromosome map composed of 371 contigs with an N50 of 1.3?Mb. Long DNA molecules achieved by our approach facilitated chromosome-scale analysis of repetitive sequences and revealed a ~800-kb array of tandem repeats intractable to current DNA sequencing technologies. Anchoring 7DS sequence assemblies obtained by clone-by-clone sequencing to the 7DS genome map provided a valuable tool to improve the BAC-contig physical map and validate sequence assembly on a chromosome-arm scale. Our results indicate that creating genome maps for the whole wheat genome in a chromosome-by-chromosome manner is feasible and that they will be an affordable tool to support the production of improved pseudomolecules.

submitted time 2016-05-04 Hits2733Downloads1530 Comment 0

6. chinaXiv:201605.00467 [pdf]

First‐generation HapMap in Cajanus spp. reveals untapped variations in parental lines of mapping populations

Vinay Kumar; Aamir W. Khan; Rachit K. Saxena; Vanika Garg; Rajeev K. Varshney
Subjects: Biology >> Botany >> Plant cytology, plant genetics & plant morphology

Whole genome re-sequencing (WGRS) was conducted on a panel of 20 Cajanus spp. accessions (crossing parentals of recombinant inbred lines, introgression lines, multiparent advanced generation intercross and nested association mapping population) comprising of two wild species and 18 cultivated species accessions. A total of 791.77 million paired-end reads were generated with an effective mapping depth of ~12X per accession. Analysis of WGRS data provided 5 465 676 genome-wide variations including 4 686 422 SNPs and 779 254 InDels across the accessions. Large structural variations in the form of copy number variations (2598) and presence and absence variations (970) were also identified. Additionally, 2 630 904 accession-specific variations comprising of 2 278 571 SNPs (86.6%), 166 243 deletions (6.3%) and 186 090 insertions (7.1%) were also reported. Identified polymorphic sites in this study provide the first-generation HapMap in Cajanus spp. which will be useful in mapping the genomic regions responsible for important traits.

submitted time 2016-05-04 Hits1913Downloads978 Comment 0

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