431 research outputs found
Feasibility of an electrostatic energy harvesting device for CFCs aircraft
A novel energy harvesting concept is proposed for treating local electrostatic energy produced on flying composite
aircrafts. This work focuses on the feasibility research on collecting static charges with capacitive collectors. The
existing energy harvesting system and the electrification of the typical carbon fibre composites (CFCs) aircraft has
been reviewed. The detailed model experiments were then designed to characterize different configurations for
electrostatic energy harvesting on aeroplane. In the lab, the static charge was produced by a corona discharging
device, and a capacitor or a metal sheet was put in the electric field to collect the charges under four different
configurations. After that, the rest results for these configurations were analysed, which is followed by the
discussion about the results application on the aircraft. This work has proved that it is feasible to collect the local
static electricity on flying aircraft, and it could provide a new direction of energy harvesting system in aviation field
Research progress on bio-inspired flapping-wing rotor micro aerial vehicle development
Flapping-wing rotor (FWR) is an innovative bio-inspired micro aerial vehicle capable of vertical take-off and landing. This unique design combines active flapping motion and passive wing rotation around a vertical central shaft to enhance aerodynamic performance. The research on FWR, though relatively new, has contributed to 6% of core journal publications in the micro aerial vehicle field over the past two decades. This paper presents the first comprehensive review of FWR, analysing the current state of the art, key advances, challenges, and future research directions. The review highlights FWR’s distinctive kinematics and aerodynamic superiority compared to traditional flapping wings, fixed wings, and rotary wings, discussing recent breakthroughs in efficient, passive wing pitching and asymmetric stroke amplitude for lift enhancement. Recent experiments and remote-controlled take-off and hovering tests of single and dual-motor FWR models have showcased their effectiveness. The review compares FWR flight performance with well-developed insect-like flapping-wing micro aerial vehicles as the technology readiness level progresses from laboratory to outdoor flight testing, advancing from the initial flight of a 2.6 g prototype to the current free flight of a 60-gram model. The review also presents ongoing research in bionic flexible wing structures, flight stability and control, and transitioning between hovering and cruise flight modes for an FWR, setting the stage for potential applications.Journal of Bionic Engineerin
Provenance of late Paleozoic strata in the Yili Basin : implications for tectonic evolution of the South Tianshan orogenic belt
This research was supported by the 973 Program under grant no. 2015CB453000, the National Natural Science Foundation of China (41502109), the Cultivating Program of Middle-Aged Key Teachers of Chengdu University of Technology (KYGG201718), Innovation Team of Sedimentary Geology of Chengdu University of Technology (KYTD201703), and by the China Postdoctoral Science Foundation (2015M582528). Cawood acknowledges support from the Australian Research Council grant FL160100168.The Yili Basin in NW China preserves a late Paleozoic volcano-sedimentary succession, the provenance of which helps to constrain the tectonic evolution of the South Tianshan orogenic belt. U-Pb ages and trace-element and Hf isotopic compositions of detrital zircons from the Late Devonian to earliest early Carboniferous strata in the Yili Basin suggest that the unit contains detritus mainly derived from basement rocks and contemporaneous arc-related volcanic rocks. The age of the unconformable contact between the Dongtujinhe Formation and underlying arc-related volcanic rocks is constrained to ca. 310 Ma. This age is consistent with published data for tectonic exhumation of high- to ultrahigh-pressure ([U]HP) metamorphic rocks from the northern margin of the South Tianshan orogenic belt. Zircon U-Pb ages from the sedimentary rocks, including clasts in conglomerate, indicate that detritus of the Dongtujinhe Formation was derived from multiple sources related to uplift and erosion of the southern Yili-Central Tianshan block. The presence of abundant eclogite clasts in the conglomerate of the Keguqinshan Formation indicates that (U)HP metamorphic rocks in the South Tianshan orogenic belt were exposed and supplied detritus to the southern Yili Basin at ca. 300 Ma. The early Middle Permian clastic rocks are characterized by Early Permian detrital zircons with a single peak at 278 Ma, derived from the postcollision magmatic rocks. During the Late Permian, input of detritus from old volcanic-sedimentary rocks and basement progressively increased. Integration of the provenance data from late Paleozoic strata in the Yili Basin with the time-equivalent northern Tarim and South Tianshan regions provides a record of the northward subduction of the South Tianshan oceanic crust beneath the Yili-Central Tianshan block in the Late Devonian to late Carboniferous (380-310 Ma), followed by continent-continent collision and final amalgamation at ca. 310-300 Ma, with postcollisional extension in the Permian.Publisher PDFPeer reviewe
Bioassessment of a Drinking Water Reservoir Using Plankton: High Throughput Sequencing vs. Traditional Morphological Method
Drinking water safety is increasingly perceived as one of the top global environmental issues. Plankton has been commonly used as a bioindicator for water quality in lakes and reservoirs. Recently, DNA sequencing technology has been applied to bioassessment. In this study, we compared the effectiveness of the 16S and 18S rRNA high throughput sequencing method (HTS) and the traditional optical microscopy method (TOM) in the bioassessment of drinking water quality. Five stations reflecting different habitats and hydrological conditions in Danjiangkou Reservoir, one of the largest drinking water reservoirs in Asia, were sampled May 2016. Non-metric multi-dimensional scaling (NMDS) analysis showed that plankton assemblages varied among the stations and the spatial patterns revealed by the two methods were consistent. The correlation between TOM and HTS in a symmetric Procrustes analysis was 0.61, revealing overall good concordance between the two methods. Procrustes analysis also showed that site-specific differences between the two methods varied among the stations. Station Heijizui (H), a site heavily influenced by two tributaries, had the largest difference while station Qushou (Q), a confluence site close to the outlet dam, had the smallest difference between the two methods. Our results show that DNA sequencing has the potential to provide consistent identification of taxa, and reliable bioassessment in a long-term biomonitoring and assessment program for drinking water reservoirs
Fine mapping of a QTL for ear size on porcine chromosome 5 and identification of high mobility group AT-hook 2 (HMGA2) as a positional candidate gene
<p>Abstract</p> <p>Background</p> <p>Ear size and shape are distinct conformation characteristics of pig breeds. Previously, we identified a significant quantitative trait locus (QTL) influencing ear surface on pig chromosome 5 in a White Duroc × Erhualian F<sub>2 </sub>resource population. This QTL explained more than 17% of the phenotypic variance.</p> <p>Methods</p> <p>Four new markers on pig chromosome 5 were genotyped across this F<sub>2 </sub>population. RT-PCR was performed to obtain expression profiles of different candidate genes in ear tissue. Standard association test, marker-assisted association test and F-drop test were applied to determine the effects of single nucleotide polymorphisms (SNP) on ear size. Three synthetic commercial lines were also used for the association test.</p> <p>Results</p> <p>We refined the QTL to an 8.7-cM interval and identified three positional candidate genes i.e. <it>HMGA2</it>, <it>SOX5 </it>and <it>PTHLH </it>that are expressed in ear tissue. Seven SNP within these three candidate genes were selected and genotyped in the F<sub>2 </sub>population. Of the seven SNP, <it>HMGA2 </it>SNP (JF748727: g.2836 A > G) showed the strongest association with ear size in the standard association test and marker-assisted association test. With the F-drop test, F value decreased by more than 97% only when the genotypes of <it>HMGA2 </it>g.2836 A > G were included as a fixed effect. Furthermore, the significant association between g.2836 A > G and ear size was also demonstrated in the synthetic commercial Sutai pig line. The haplotype-based association test showed that the phenotypic variance explained by <it>HMGA2 </it>was similar to that explained by the QTL and at a much higher level than by <it>SOX5</it>. More interestingly, <it>HMGA2 </it>is also located within the dog orthologous chromosome region, which has been shown to be associated with ear type and size.</p> <p>Conclusions</p> <p><it>HMGA2 </it>was the closest gene with a potential functional effect to the QTL or marker for ear size on chromosome 5. This study will contribute to identify the causative gene and mutation underlying this QTL.</p
Modelling and simulation of a novel bioinspired flapping-wing rotary MAV
© The AuthosAchieving high lift efficiency represents a major research focus in the Micro Air Vehicle (MAV) domain due to stringent size and payload constraints. The Cranfield research team presents a novel semi-biomimetic design called the Flapping Wing Rotor (FWR) to address this challenge. This innovative concept combines a bioinspired flapping wing mechanism with passive rotor rotation, leveraging unsteady aerodynamic principles analogous to insect flight. The research aims to highlight a promising biomimetic flapping-rotor MAV enabled through advanced modeling to unlock the benefits of bio-inspired unsteady aerodynamics. To demonstrate this approach, a 60g proof-of-concept prototype was developed alongside a digital twin methodology for modeling, simulation, and control. A mathematical model has been formulated to analyze FWR's lift generation performance and enable flight control system design for stabilization and controllability. This work concentrates on enhancing the physical modeling process. The model is refined by tuning two key aerodynamic coefficients to account for nonlinearities from unsteady aerodynamics, flexible structures, and low Reynolds number flow inherent in MAV flight. This improved model achieves superior lift prediction accuracy versus real flight test data. Ongoing efforts focus on optimizing control torque, load distribution, and stability to further augment FWR's flight capabilities
Aerodynamic performance of a flyable flapping wing rotor with dragonfly-like flexible wings
Drawing inspiration from insect flapping wings, a Flapping Wing Rotor (FWR) has been developed for Micro Aerial Vehicle (MAV) applications. The FWR features unique active flapping and passive rotary kinematics of motion to achieve a high lift coefficient and flight efficiency. This study thoroughly investigates the aerodynamic performance and design of a bio-inspired flexible wing for FWR-MAVs, emphasizing its novel backward-curved wingtip and variable spanwise stiffness resembling a dragonfly's wing. The research departs from previous aerodynamic studies of FWR, which focused predominantly on rectangular and rigid wings, and delves into wing flexibility. Employing Computational Fluid Dynamics (CFD), Computational Structural Dynamics (CSD), and experimental measurements, the study demonstrates the aerodynamic benefits of the dragonfly-inspired FWR wingtip shape and its reinforced structure. Fluid-Structure Interaction (FSI) analysis is used to examine the effects of elastic deformation encompassing twist and bending on aerodynamic forces. The results underscore the importance of bending deformation in enhancing lift and power efficiency and propose a method for analysing variable stiffness along the wingspan using a vortex delay mechanism that is induced by delayed flapping motion. By comparing modelled and measured stiffness, the study validates the flexibility of the FWR wing, revealing optimal aerodynamic efficiency is achieved through moderate flexibility and spanwise stiffness variation. The curving leading-edge beam forming the sweep-back wingtip offers a practical approach to obtaining variable stiffness and aerodynamic benefits for FWR-MAVs. Using the same pair of dragonfly-like flexible wings, FWR-MAVs have effectively exhibited VTOL and hovering flight capabilities, spanning from a 25-g single-motor drive model to a 51-g dual-motor drive model. This research provides valuable insights into flexible wing design for FWR-MAVs, leveraging biomimicry to improve flight efficiency
Genome-wide identification of QTL for age at puberty in gilts using a large intercross F2 population between White Duroc and Erhualian
Puberty is a fundamental development process experienced by all reproductively competent adults, yet the specific factors regulating age at puberty remain elusive in pigs. In this study, we performed a genome scan to identify quantitative trait loci (QTL) affecting age at puberty in gilts using a White Duroc × Erhualian intercross. A total of 183 microsatellites covering 19 porcine chromosomes were genotyped in 454 F2 gilts and their parents and grandparents in the White Duroc × Erhualian intercross. A linear regression method was used to map QTL for age at puberty via QTLexpress. One 1% genome-wise significant QTL and one 0.1% genome-wise significant QTL were detected at 114 cM (centimorgan) on SSC1 and at 54 cM on SSC7, respectively. Moreover, two suggestive QTL were found on SSC8 and SSC17, respectively. This study confirmed the QTL for age at puberty previously identified on SSC1, 7 and 8, and reports for the first time a QTL for age at puberty in gilts on SSC17. Interestingly, the Chinese Erhualian alleles were not systematically favourable for younger age at puberty
Sexually dimorphic genetic architecture of complex traits in a large-scale F2 cross in pigs
BACKGROUND: It is common for humans and model organisms to exhibit sexual dimorphism in a variety of complex traits. However, this phenomenon has rarely been explored in pigs. RESULTS: To investigate the genetic contribution to sexual dimorphism in complex traits in pigs, we conducted a sex-stratified analysis on 213 traits measured in 921 individuals produced by a White Duroc × Erhualian F(2) cross. Of the 213 traits examined, 102 differed significantly between the two sexes (q value <0.05), which indicates that sex is an important factor that influences a broad range of traits in pigs. We compared the estimated heritability of these 213 traits between males and females. In particular, we found that traits related to meat quality and fatty acid composition were significantly different between the two sexes, which shows that genetic factors contribute to variation in sexual dimorphic traits. Next, we performed a genome-wide association study (GWAS) in males and females separately; this approach allowed us to identify 13.6% more significant trait-SNP (single nucleotide polymorphism) associations compared to the number of associations identified in a GWAS that included both males and females. By comparing the allelic effects of SNPs in the two sexes, we identified 43 significant sexually dimorphic SNPs that were associated with 22 traits; 41 of these 43 loci were autosomal. The most significant sexually dimorphic loci were found to be associated with muscle hue angle and Minolta a* values (which are parameters that reflect the redness of meat) and were located between 9.3 and 10.7 Mb on chromosome 6. A nearby gene i.e. NUDT7 that plays an important role in heme synthesis is a strong candidate gene. CONCLUSIONS: This study illustrates that sex is an important factor that influences phenotypic values and modifies the effects of the genetic variants that underlie complex traits in pigs; it also emphasizes the importance of stratifying by sex when performing GWAS. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12711-014-0076-2) contains supplementary material, which is available to authorized users
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