Mechanism of integrated forming of shape and inner hole of hollow axle

The paper introduces a new technology of the integrated forming of shape and inner hole of hollow axle. Firstly, the design of the process is described. Secondly, the range of feed angle of two sets of rolls and the principle to be followed are explained. Finally, the rolling process of hollow axle is simulated by Finite Element Method (FEM), and the variation law of load parameters and the distribution law of temperature and effective plastic strain in the rolling process are analyzed.The numerical results verify the feasibility of rolling hollow axle with this process

Mechanism of integrated forming of shape and inner hole of hollow axle

The paper introduces a new technology of the integrated forming of shape and inner hole of hollow axle. Firstly, the design of the process is described. Secondly, the range of feed angle of two sets of rolls and the principle to be followed are explained. Finally, the rolling process of hollow axle is simulated by Finite Element Method (FEM), and the variation law of load parameters and the distribution law of temperature and effective plastic strain in the rolling process are analyzed.The numerical results verify the feasibility of rolling hollow axle with this process

Research on integrated forming process of three-roll reducing and thickening of necking section for thin-walled tube of aluminum alloy 2A12

Aircraft joystick pipe is the key part of aircraft hard control system. In this paper, a hollow necking rod pipe made of aluminum alloy 2A12 is taken as the research object. The tapered roller with extrusion cone on one side of the roller surface is designed. Simufact.Forming14.0 was used to analyze. It was found that the radial rolling force at the end of the thickening section in the second pass increased sharply. At this time, the retaining part inhibited the axial extension of the metal and realized the accumulation in the thickness direction. The thickening rate and effect were favorable at 120 rpm, which provide a theoretical basis to realize integrated forming of aeronautical thin-walled aluminum alloy tube

Research on integrated forming process of three-roll reducing and thickening of necking section for thin-walled tube of aluminum alloy 2A12

Aircraft joystick pipe is the key part of aircraft hard control system. In this paper, a hollow necking rod pipe made of aluminum alloy 2A12 is taken as the research object. The tapered roller with extrusion cone on one side of the roller surface is designed. Simufact.Forming14.0 was used to analyze. It was found that the radial rolling force at the end of the thickening section in the second pass increased sharply. At this time, the retaining part inhibited the axial extension of the metal and realized the accumulation in the thickness direction. The thickening rate and effect were favorable at 120 rpm, which provide a theoretical basis to realize integrated forming of aeronautical thin-walled aluminum alloy tube

Viruses mobilize plant immunity to deter nonvector insect herbivores.

A parasite-infected host may promote performance of associated insect vectors; but possible parasite effects on nonvector insects have been largely unexplored. Here, we show that Begomovirus, the largest genus of plant viruses and transmitted exclusively by whitefly, reprogram plant immunity to promote the fitness of the vector and suppress performance of nonvector insects (i.e., cotton bollworm and aphid). Infected plants accumulated begomoviral βC1 proteins in the phloem where they were bound to the plant transcription factor WRKY20. This viral hijacking of WRKY20 spatiotemporally redeployed plant chemical immunity within the leaf and had the asymmetrical benefiting effects on the begomoviruses and its whitefly vectors while negatively affecting two nonvector competitors. This type of interaction between a parasite and two types of herbivores, i.e., vectors and nonvectors, occurs widely in various natural and agricultural ecosystems; thus, our results have broad implications for the ecological significance of parasite-vector-host tripartite interactions

Research on metal reflow law of three roll skew rolling (TRSR) hollow axle

In the process of TRSR hollow axle, there is metal reflow on the surface of the rolled piece, which greatly reduces the forming accuracy of the rolled piece. To solve this problem, it is necessary to study the metal reflow law of axle body. First, the flow law of metal on the surface of rolled piece is obtained by point tracking method. Moreover, the effects of process parameters on the metal reflow degree of axle body are carried out, and the influence law of process parameters on the metal reflow degree of axle body is obtained. Finally, by comparing the results of the experiment and the simulation, the reliability of the simulation is proved

Genomic Inference of the Metabolism and Evolution of the Archaeal Phylum Aigarchaeota

Microbes of the phylum Aigarchaeota are widely distributed in geothermal environments, but their physiological and ecological roles are poorly understood. Here we analyze six Aigarchaeota metagenomic bins from two circumneutral hot springs in Tengchong, China, to reveal that they are either strict or facultative anaerobes, and most are chemolithotrophs that can perform sulfide oxidation. Applying comparative genomics to the Thaumarchaeota and Aigarchaeota, we find that they both originated from thermal habitats, sharing 1154 genes with their common ancestor. Horizontal gene transfer played a crucial role in shaping genetic diversity of Aigarchaeota and led to functional partitioning and ecological divergence among sympatric microbes, as several key functional innovations were endowed by Bacteria, including dissimilatory sulfite reduction and possibly carbon monoxide oxidation. Our study expands our knowledge of the possible ecological roles of the Aigarchaeota and clarifies their evolutionary relationship to their sister lineage Thaumarchaeota

New Views on Strand Asymmetry in Insect Mitochondrial Genomes

Strand asymmetry in nucleotide composition is a remarkable feature of animal mitochondrial genomes. Understanding the mutation processes that shape strand asymmetry is essential for comprehensive knowledge of genome evolution, demographical population history and accurate phylogenetic inference. Previous studies found that the relative contributions of different substitution types to strand asymmetry are associated with replication alone or both replication and transcription. However, the relative contributions of replication and transcription to strand asymmetry remain unclear. Here we conducted a broad survey of strand asymmetry across 120 insect mitochondrial genomes, with special reference to the correlation between the signs of skew values and replication orientation/gene direction. The results show that the sign of GC skew on entire mitochondrial genomes is reversed in all species of three distantly related families of insects, Philopteridae (Phthiraptera), Aleyrodidae (Hemiptera) and Braconidae (Hymenoptera); the replication-related elements in the A+T-rich regions of these species are inverted, confirming that reversal of strand asymmetry (GC skew) was caused by inversion of replication origin; and finally, the sign of GC skew value is associated with replication orientation but not with gene direction, while that of AT skew value varies with gene direction, replication and codon positions used in analyses. These findings show that deaminations during replication and other mutations contribute more than selection on amino acid sequences to strand compositions of G and C, and that the replication process has a stronger affect on A and T content than does transcription. Our results may contribute to genome-wide studies of replication and transcription mechanisms

Impact of wind loads on the resistance capacity of the transmission tower subjected to ground surface deformations

China State Grid Corporatio