Erosion wear behaviour and model of abradable seal coating

International audienceThe abradable seal coating for an aircraft turbine engine is mostly composed of metal phase, self-lubricating non-metal phase and many pores. The erosion wear resistance is one of the most important properties of the coating. The erosion wear behaviour and mechanism of several kinds of middle temperature seal coatings were investigated by a CMS-100 self-made vacuum sand erosion machine. The results show that the relationship between the erosion mass loss and the erosion time is linear, the coatings hold a maximum erosion rate at 60° impact angle, and the relation between the erosion rate and the impact speed is an exponential function. The speed exponent increases with the increase of the impact angle. At 90° impact, the abrasive particles impinging on the coating surface produce indentations and extruded lips, and then the lips are work-hardened and fall off; and flattened metal phase grains are impacted repeatedly, loosed and debonded. At 30° impact, the micro-cutting, plowing and tunneling via pores and non-metal phase are involved. The model of the erosion mechanism is advanced on the basis of the above-mentioned erosion wear behaviour

Friction and wear behaviour and abradability of abradable seal coating

International audienceThe friction and wear behaviour of several kinds of middle temperature abradable seal coatings used in aircraft turbine engine was investigated. Their abradability was evaluated by sliding worn volume. The mechanisms of the sliding wear of the coatings are abrasive wear, adhesive wear and oxidation wear, but the weight of the adhesive wear and abrasive wear is different in different coatings and under different test loads. The results show that the abradability decreases with the increase of the hardness for a given kind of coating. Even if the hardness is close, the abradability is very different in different kinds of coatings. So, only by the hardness can the level of abradability not be not judged and the coating not be chosen and designed. The abradability of M313 type of coating is the best, M310 is close to M601 and M307 with low hardness is fairly good, but M307 with high hardness is the worst

Research Progress in Cemented Carbide with Co-Ni-Al Composite Binder Phase

The application background of Co-Ni-Al composite binder phase in cemented carbide was introduced. The latest research results of Co-based superalloy and the properties of cemented carbide with binder strengthened by ordered phase were briefly described. The application of integrated computational material engineering in the research and development of Co-Ni-Al composite binder was introduced. The progress in the preparation, microstructure characterization and performance of WC-Co-Ni-Al cemented carbides were summarized. The results show that the composition of Co-Ni-Al composite binder has obvious influence on the solid-liquid interface energy and the liquid-phase nucleation driving force of the alloy. Accordingly, the grain size of the binder phase and the grain morphology of WC are affected. Ultimately these factors affect the performance of the alloy. It is pointed out that the performance of cemented carbide strengthened by ordered γ′ phase precipitation can be improved significantly. It is expected to obtain high-performance cemented carbide materials with excellent high-temperature resistance, corrosion resistance and oxidation resistance. It is proposed that the interfacial microstructure, the relationship between C content and precipitation phase and the anti-wear mechanism of cemented carbide with Co-Ni-Al composite binder phase should be emphasized in future

Present Situation and Development Measures of Beef Cattle Industry in Xuanhan County

This paper analyzes the actual situation and bottleneck problems in the development of beef cattle industry in Xuanhan County. In view of the existing problems, this paper puts forward reasonable suggestions, with a view to better exploring the development model of characteristic beef cattle industry in Xuanhan County based on the unique cattle resources of Xuanhan County, and effectively promoting the implementation of the strategy of rural revitalization

Development Status and Strategies of Xieka

In this paper, the present situation of Xieka cattle was investigated, and the body size of Xieka cattle was measured. It was found that there were some problems in Xieka cattle, such as backward feeding and management, and degradation of breeds. The corresponding strategies were put forward in order to promote the resource protection, development and utilization of Xieka cattle

Solvent-Controlled, Tunable Hydrosulfonylation of 3‑Cyclopropylideneprop-2-en-1-ones

An interesting and tunable hydrosulfonylation of 3-cyclo­propylidene­prop-2-en-1-ones with sodium sulfinates and acetic acid is described. The corresponding β- or γ-addition products can be produced in good to excellent yields with high selectivities, respectively. A rationale for these transformations is proposed base on the controlled experiments

Discovery of genome-wideSNPs by RAD-seqand the genetic diversity of captive hog deer (Axis porcinus).

The hog deer (Axis porcinus) is a small deer whose natural habitat is the wet or moist tall grasslands in South and Southeast Asia. Wild populations have dramatically decreased in recent decades. While wild hog deer were recently acknowledged to be extinct in China, a few captive populations have been maintained. In the present study, we successfully employed the restriction-site-associated DNA sequencing (RAD-seq) technique to generate a genome-wide profile of single-nucleotide polymorphisms (SNPs) in the captive population of hog deer from Chengdu Zoo, China (N = 11). Up to 4.7 million clean reads per sample were sequenced, and 11,155 SNPs and 8,247 haplotypes were simultaneously observed within more than 80% of sequenced individuals. In this population, the mean frequency of major alleles at each polymorphism site was 0.7903±0.0014, and the average nucleotide diversity (π) and inbreeding coefficient (FIS) were 0.3031±0.0015 and -0.0302±0.0062, respectively. Additionally, the Euclidean distance-based multidimensional scaling method revealed that the pairwise genetic relatedness was evenly distributed. However, the results of homologous searching by short reads did not provide any meaningful explanation of the phylogenetic relationship of hog deer, which should be further investigated. In conclusion, our results revealed current state of genetic diversity in this captive population of hog deer.Furthermore, these genome-wide SNPs would be useful for guiding the mating schedule to avoid sharp increase of inbreeding coefficient

Determination of Breeding Target and Marginal Benefit Calculation of New Type of Shuxuan Beef Cattle

[Objectives] To make targeted breeding of new type of Shuxuan beef cattle, study and determine the breeding target traits of new type of Shuxuan beef cattle. [Methods] The difference method was used to calculate the marginal benefit of each target trait, and the economic weight of the corresponding breeding target trait was obtained. [Results] The marginal benefits of weaning weight, fattening daily gain, 18-month weight, carcass quality, dressing percentage, pure meat percentage, age at first calving, calving interval and stay group time were 35.86, 13.76, 13.05, 421.96, 375.55, 22.58, -4.45, -27.53, and 1 555.24, respectively. The relative economic weight ratio of growth traits, carcass traits, and reproductive traits was close to 4:1:5. Through marginal benefit analysis, the economic benefits obtained by improving carcass quality, dressing percentage and stay group time were significantly higher than other traits. [Conclusions] It is expected to provide a theoretic basis for establishing the target trait selection indicators for the new type of Shuxuan beef cattle

Simultaneous introgression of three <i>POLLED</i> mutations into a synthetic breed of Chinese cattle

<div><p>The polled phenotype of cattle is increasingly becoming favourable mainly because of the enhanced emphasis on animal welfare, for which the causative mutations have been reported during the past years. The Shuxuan cattle are a new synthetic breed by crossing the indigenous cattle with both Simmental and Holstein semen in Sichuan of Southwest China, in which about 15% of polled individuals have newly emerged. Because official record about <i>POLLED</i> genotypes for the historically imported sires is unavailable, we therefore genotyped the proposed <i>POLLED</i> variants of P_202ID, P_80kbID and P_219ID among 48 polled and 16 horned Shuxuan cattle. It was first revealed that all three candidate mutations have been simultaneously introgressed into Shuxuan cattle, whereas the P_202ID mutation is dominant. Furthermore, one polled animal still remains to carry none of the three candidate mutations, which suggests that further mutation(s) would also exist. Additionally, we sequenced mitochondrial DNA and found that Shuxuan cattle are composed of two matrilineal origins of <i>Bos taurus</i> (65.6%) and <i>B</i>. <i>indicus</i> (34.4%); and there is no origin-biased distribution of polled phenotype. In conclusion, our study first supports the recently reported novel candidate mutation of P_219ID and detects simultaneous presences of all three known <i>POLLED</i> mutations within a cattle breed.</p></div