Review of Aircraft Vibration Environment Prediction Methods

AbstractAircraft vibration response environment prediction, which is adopted in aircraft initial vehicle development, has not been got enough attention and wide application yet. This paper briefly reviews theoretical and engineering significance of aircraft vibration response environment prediction firstly. Then the paper summarizes the main aircraft vibration response environment prediction methods and indicates their advantages, disadvantages and applicability scopes, including extrapolation of similar structure, theory analysis and analytical solution of differential dynamical equation, statistical parameter modeling, simulation calculation modeling and machine learning. Finally, the paper points out that uncertainty and non-linear structures, nonstationary signal analysis and complex vibration environment response prediction are major problems for aircraft vibration response prediction and directions for future research work

Resonant tunneling through a C60 molecular junction in liquid environment

We present electronic transport measurements through thiolated C$_{60}$ molecules in liquid environment. The molecules were placed within a mechanically controllable break junction using a single anchoring group per molecule. When varying the electrode separation of the C$_{60}$-modified junctions, we observed a peak in the conductance traces. The shape of the curves is strongly influenced by the environment of the junction as shown by measurements in two distinct solvents. In the framework of a simple resonant tunneling model, we can extract the electronic tunneling rates governing the transport properties of the junctions.Comment: 13 pages, 4 figures. To appear in Nanotechnolog

Limosilactobacillus balticus sp. nov., Limosilactobacillus agrestis sp. nov., Limosilactobacillus albertensis sp. nov., Limosilactobacillus rudii sp. nov. and Limosilactobacillus fastidiosus sp. nov., five novel Limosilactobacillus species isolated from the vertebrate gastrointestinal tract, and proposal of six subspecies of Limosilactobacillus reuteri adapted to the gastrointestinal tract of specific vertebrate hosts

Ten strains, BG-AF3-A(T), pH52_RY, WF-MT5-A(T), BG-MG3-A, Lr3000(T), RRLNB_1_1, STM3_1(T), STM2_1, WF-MO7-1(T) and WF-MA3-C, were isolated from intestinal or faecal samples of rodents, pheasant and primate. 16S rRNA gene analysis identified them as Limosilactobacillus reuteri. However, average nucleotide identity and digital DNA-DNA hybridization values based on whole genomes were below 95 and 70%, respectively, and thus below the threshold levels for bacterial species delineation. Based on genomic, chemotaxonomic and morphological analyses, we propose five novel species with the names Limosilactobacillus balticus sp. nov. (type strain BG-AF3-A(T)=DSM 110574(T)=LMG 31633(T)), Limosilactobacillus agrestis sp. nov. (type strain WF-MT5-A(T)=DSM 110569(T)=LMG 31629(T)), Limosilactobacillus albertensis sp. nov. (type strain Lr3000(T)=DSM 110573(T)=LMG 31632(T)), Limosilactobacillus rudii sp. nov. (type strain STM3_1(T)=DSM 110572(T)=LMG 31631(T)) and Limosilactobacillus fastidiosus sp. nov. (type strain WF-MO7-1(T)=DSM 110576(T)=LMG 31630(T)). Core genome phylogeny and experimental evidence of host adaptation of strains of L. reuteri further provide a strong rationale to consider a number of distinct lineages within this species as subspecies. Here we propose six subspecies of L. reuteri: L. reuteri subsp. kinnaridis subsp. nov. (type strain AP3(T)=DSM 110703(T)=LMG 31724(T)), L. reuteri subsp. porcinus subsp. nov. (type strain 3c6(T)=DSM 110571(T)=LMG 31635(T)), L. reuteri subsp. murium subsp. nov. (type strain lpuph1(T)=DSM 110570(T)=LMG 31634(T)), L. reuteri subsp. reuteri subsp. nov. (type strain F 275(T)=DSM 20016(T)=ATCC 23272(T)), L. reuteri subsp. suis subsp. nov. (type strain 1063(T)=ATCC 53608(T)=LMG 31752(T)) and L. reuteri subsp. rodentium subsp. nov. (type strain 100-23(T)=DSM 17509(T)=CIP 109821(T))

SPH fluids for viscous jet buckling

We present a novel meshfree technique for animating\ud free surface viscous liquids with jet buckling effects, such as\ud coiling and folding. Our technique is based on Smoothed Particle\ud Hydrodynamics (SPH) fluids and allows more realistic and\ud complex viscous behaviors than the preceding SPH frameworks\ud in computer animation literature. The viscous liquid is modeled\ud by a non-Newtonian fluid flow and the variable viscosity under\ud shear stress is achieved using a viscosity model known as Cross\ud model. The proposed technique is efficient and stable, and our\ud framework can animate scenarios with high resolution of SPH\ud particles in which the simulation speed is significantly accelerated\ud by using Computer Unified Device Architecture (CUDA)\ud computing platform. This work also includes several examples\ud that demonstrate the ability of our technique.FAPESP - processos nos. 2013/19760-5 e 2014/11981-5FAPES - processos no. 53600100/11CNP

Ecological importance of cross-feeding of the intermediate metabolite 1,2-propanediol between bacterial gut symbionts

Cross-feeding based on the metabolite 1,2-propanediol has been proposed to have an important role in the establishment of trophic interactions among gut symbionts, but its ecological importance has not been empirically established. Here, we show that in vitro growth of Lactobacillus reuteri ATCC PTA 6475 is enhanced through 1,2-propanediol produced by Bifidobacterium breve UCC2003 and Escherichia coli MG1655 from the metabolization of fucose and rhamnose, respectively. Work with isogenic mutants showed that the tropic interaction is dependent on the pduCDE operon in L. reuteri, which encodes for the ability to use 1,2-propanediol, and the L-fucose permease (fucP) gene in B. breve, which is required for 1,2-propanediol formation from fucose. Experiments in gnotobiotic mice revealed that, although the pduCDE operon bestows a fitness burden on L. reuteri ATCC PTA 6475 in the mouse digestive tract, the ecological performance of the strain was enhanced in the presence of B. breve UCC2003 and the mucus-degrading species Bifidobacterium bifidum The use of the respective pduCDE and fucP mutants of L. reuteri and B. breve in the mouse experiments indicated that the trophic interaction was specifically based on 1,2-propanediol. Overall, our work established the ecological importance of cross-feeding relationships based on 1,2-propanediol for the fitness of a bacterial symbiont in the vertebrate gut.Importance Through experiments in gnotobiotic mice that employed isogenic mutants of bacterial strains that produce (Bifidobacterium breve) and utilize (Lactobacillus reuteri) 1,2-propanediol, this study provides mechanistic insight into the ecological ramifications of a trophic interaction between gut symbionts. The findings improve our understanding on how cross-feeding influences the competitive fitness of L. reuteri in the vertebrate gut and revealed a putative selective force that shaped the evolution of the species. The findings are relevant as they provide a basis to design rational microbial-based strategies to modulate gut ecosystems, which could employ mixtures of bacterial strains that establish trophic interactions or a personalized approach based on the ability of a resident microbiota to provide resources for the incoming microbe

Structural variation and introgression from wild populations in East Asian cattle genomes confer adaptation to local environment

BACKGROUND: Structural variations (SVs) in individual genomes are major determinants of complex traits, including adaptability to environmental variables. The Mongolian and Hainan cattle breeds in East Asia are of taurine and indicine origins that have evolved to adapt to cold and hot environments, respectively. However, few studies have investigated SVs in East Asian cattle genomes and their roles in environmental adaptation, and little is known about adaptively introgressed SVs in East Asian cattle. RESULTS: In this study, we examine the roles of SVs in the climate adaptation of these two cattle lineages by generating highly contiguous chromosome-scale genome assemblies. Comparison of the two assemblies along with 18 Mongolian and Hainan cattle genomes obtained by long-read sequencing data provides a catalog of 123,898 nonredundant SVs. Several SVs detected from long reads are in exons of genes associated with epidermal differentiation, skin barrier, and bovine tuberculosis resistance. Functional investigations show that a 108-bp exonic insertion in SPN may affect the uptake of Mycobacterium tuberculosis by macrophages, which might contribute to the low susceptibility of Hainan cattle to bovine tuberculosis. Genotyping of 373 whole genomes from 39 breeds identifies 2610 SVs that are differentiated along a "north-south" gradient in China and overlap with 862 related genes that are enriched in pathways related to environmental adaptation. We identify 1457 Chinese indicine-stratified SVs that possibly originate from banteng and are frequent in Chinese indicine cattle. CONCLUSIONS: Our findings highlight the unique contribution of SVs in East Asian cattle to environmental adaptation and disease resistance

Effects of gravity and buoyancy on spontaneous liquid-liquid imbibition in fractured porous media

Spontaneous imbibition in porous materials has received significant attention in recent decades; however, spontaneous liquid-liquid imbibition in fractures has not been well studied. Specifically, the mechanism behind the influence of gravity and buoyancy on the spontaneous imbibition of wetting phase fluid into fractured porous media remains uncertain. In this study, an analytical solution for spontaneous imbibition in fractured porous media under the influence of gravity and buoyancy is presented. The results show that imbibition velocity with buoyancy and gravity is faster than that without these forces. The effect of buoyancy and gravity on imbibition velocity increases with rising fracture aperture and length. When the fracture aperture is less than 1 μm, the relative deviation between imbibition height with and without gravity and buoyancy is about 50%. On the other hand, when the fracture aperture is greater than 1 μm, the relative deviation is proportional to the fracture aperture. The relative reduction in imbibition height over time is not obvious when the fracture aperture is the same. In the process of water-oil spontaneous imbibition, the effect of buoyancy and gravity is more pronounced at low oil-water interfacial tension. Therefore, the effect of buoyancy and gravity on spontaneous imbibition cannot be ignored under this condition.Document Type: Original articleCited as: Cheng, H., Wang, F. Effects of gravity and buoyancy on spontaneous liquid-liquid imbibition in fractured porous media. Capillarity, 2024, 10(1): 1-11. https://doi.org/10.46690/capi.2024.01.0