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Disease-related milk losses directly affect dairy herds' profitability and the production efficiency of the dairy industry. Therefore, this study aimed to quantify phenotypic variability in milk fluctuation periods related to diseases and to explore milk fluctuation traits as indicators of disease resilience. By combining high-frequency daily milk yield data with disease records of cows that were treated and recovered from the disease, we estimated milk variability trends within a fixed period around the treatment day of each record for 5 diseases: udder health, reproductive disorders, metabolic disorders, digestive disorders, and hoof health. The average milk yield decreased rapidly from 6 to 8 d before the treatment day for all diseases, with the largest milk reduction observed on the treatment day. Additionally, we assessed the significance of milk fluctuation periods highly related to diseases by defining milk fluctuations as a period of at least 10 consecutive days in which milk yield fell below 90% of the expected milk production values at least once. We defined the development and recovery phases of milk fluctuations using 3,847 milk fluctuation periods related to disease incidences, and estimated genetic parameters of milk fluctuation traits, including milk losses, duration of the fluctuation, variation rate in daily milk yield, and standard deviation of milk deviations for each phase and their genetic correlation with several important traits. In general, the disease-related milk fluctuation periods lasted 21.19 ± 10.36 d with a milk loss of 115.54 ± 92.49 kg per lactation. Compared with the development phase, the recovery phase lasted an average of 3.3 d longer, in which cows produced 11.04 kg less milk and exhibited a slower variation rate in daily milk yield of 0.35 kg/d. There were notable differences in milk fluctuation traits depending on the disease, and greater milk losses were observed when multiple diseases occurred simultaneously. All milk fluctuation traits evaluated were heritable with heritability estimates ranging from 0.01 to 0.10, and moderate to high genetic correlations with milk yield (0.34 to 0.64), milk loss throughout the lactation (0.22 to 0.97), and resilience indicator (0.39 to 0.95). These results indicate that cows with lower milk losses and higher resilience tend to have more stable milk fluctuations, which supports the potential for breeding for more disease-resilient cows based on milk fluctuation traits. Overall, this study confirms the high effect of diseases on milk yield variability and provides insightful information about their relationship with relevant traits in Holstein cattle. Furthermore, this study shows the potential of using high-frequency automatic monitoring of milk yield to assist on breeding practices and health management in dairy cows. [ABSTRACT FROM AUTHOR]

A kite‐shaped low‐band (LB) element loaded with mushroom‐shaped structure is proposed. The element has a bandpass characteristic for the electromagnetic wave within the frequency range of 3.4–3.8 GHz and can reduce the influence on the high‐band (HB) antenna in the dual‐band coaperture antenna. The LB elements operating in the 0.698–0.96 GHz frequency band are embedded in the massive multiple input, multiple output (MIMO) antenna. One prototype of the coaperture antenna is fabricated for demonstration. The measured results show that the pattern distortion of most of the antenna ports of the HB antenna is very small after adding the LB antenna. The maximum gain deviation of the traffic beam scanning within the range of ±60° is less than 0.57 dB, indicating that the LB element can effectively suppress scattering and is suitable for multiband coaperture base‐station antenna. [ABSTRACT FROM AUTHOR]

Ultrasonic elliptical vibration cutting (UEVC) has been successfully applied to precision machining of difficult-to-machine materials with its advantages of low machined surface roughness and low tool wear. In this study, an eccentric cone UEVC tool is proposed based on the mechanical vibration theory, with the idea of combining longitudinal vibration and bending vibration. The preliminary dimensions of the UEVC tool are obtained by theoretical calculations. Then, the dimensions of the tool are optimized through finite element analysis (FEA) to meet the requirements of vibration modes and resonant frequencies. Finally, a prototype of the eccentric cone UEVC tool is developed, and the vibration performance tests and cutting experiments are conducted on the designed tool to verify its cutting trajectory and cutting performance. According to the results, the new developed eccentric cone UEVC tool can achieve the elliptical vibration trajectory at the tool tip; the resonant frequency of the tool is 28019 Hz; and the longitudinal and the bending amplitude are 6.2 μm and 4.9 μm, respectively. The new developed eccentric cone UEVC tool can obtain workpieces with the surface roughness about 0.337 μm and reduced the tool wear. [ABSTRACT FROM AUTHOR]

In cutting, the mechanical impact caused by material mechanics, geometric discontinuity, and intermittent cutting process is the main factor that induces cutting tool fracture. Impact fracture and fatigue failure of cutting tools are sudden, which can be harmful to safe production and quality control. In this paper, the effect mechanism of shim stiffness on the impact fracture performance of a tool in a mechanically clamped cutting tool system is studied. Furthermore, the vibration model of the tool-shim system is established to analyze the impact loading response characteristics of the tool-shim system under different stiffness shims. Meanwhile, the effect of shim stiffness on the loading rate, peak value, high-level fluctuation, unloading rate, and elastic energy release of shim elastic reaction force is explored. Apart from that, theoretical analysis of the stress field change near the tool crack tip is carried out. Finally, intermittent turning experiments are performed, including carbide inserts with four shims of N8 aluminum alloy, TC4 titanium alloy, 08 steel, and YT14 cemented carbide. Moreover, the analysis of each stage of the vibration response is verified. According to the results, the stiffness of the shim affects both the impact fracture of the tool basal body and the coating peeling. Besides, appropriately weakening the shim stiffness can reduce the load peak value of the shim elastic reaction force on the tool, the high load fluctuation amplitude, the unloading rate, and the dynamic stress intensity factor (DSIF), which can be conductive to improving the impact damage resistance of the tool. [ABSTRACT FROM AUTHOR]

This study investigated the reliability of genomic prediction (GP) using breed origin of alleles (BOA) approach in the Nordic Red (RDC) population, which has an admixed population structure. The RDC population consists of animals with varying degrees of genetic materials from the Danish Red (RDM), Swedish Red (SRB), Finnish Ayrshire (FAY), and Holstein (HOL) because bulls have been used across the breeds. The BOA approach was tested using 39,550 RDC animals in the reference population and 11,786 in the validation population. Deregressed proofs (DRP) of milk, fat and protein were used as response variable for GP. Direct genomic breeding values (DGV) for animals in the validation population were calculated with (BOA model) or without (joint model) considering breed origin of alleles. The joint model assumed homogeneous marker effects and a single set of marker effects were estimated, whereas BOA model assumed heterogeneous marker effects, and different sets of marker effects were estimated across the breeds. For the BOA approach, we tested scenarios assuming both correlated (BOA_cor) and uncorrelated (BOA_uncor) marker effects between the breeds. Additionally, we investigated GP using a standard Illumina 50K chip and including SNP selected from imputed whole-genome sequencing (50K+WGS). We also studied the effect of estimating (co)variances for genome regions of different sizes to exploit the information of the genome regions contributing to the (co)variance between the breeds. Region sizes were set as 1 SNP, a group of 30 or 100 adjacent SNP, or the whole genome. Reliability of DGV was measured as squared correlations between DGV and DRP divided by the reliability of DRP. Across the 3 traits, in general, RS30 and RS100 SNP yielded the highest reliabilities. Including WGS SNP improved reliabilities in almost all scenarios (0.297 on average for 50K and 0.307 on average for 50K+WGS). The BOA_uncor (0.233 on average) was inferior to the joint model (0.339 on average), but the reliabilities obtained using BOA_cor (0.334 on average) in most cases were not significantly different from those obtained using the joint model. The results indicate that both including additional whole-genome sequencing SNP and dividing the genome into fixed regions improve GP in the RDC. The BOA models have the potential to increase the reliability of GP, but the benefit is limited in populations with a high exchange of genetic material for a long time, as is the case for RDC. [ABSTRACT FROM AUTHOR]

Rationale: Pyrotinib is an irreversible EGFR/HER2 inhibitor that has shown antitumor activity and tolerance in the treatment of breast cancer. Studies focused on its metabolic pathways and major metabolites are insufficient. In the evaluation of drug safety and therapeutic use, metabolite characterization is critical. The metabolism of pyrotinib in vitro was studied utilizing rat, dog and human hepatocytes in this study. Methods: Pyrotinib (10 μM) was incubated with hepatocytes in Williams' E medium. The metabolites were examined and profiled using ultrahigh‐performance liquid chromatography coupled with quadrupole/orbitrap high‐resolution mass spectrometry. The metabolite structures were deduced by comparing their precise molecular weights, fragment ions and retention times with those of the parent drug. Results: A total of 16 metabolites, including 6 novel ones, were discovered and structurally described under the present conditions. Oxidation, demethylation, dehydrogenation, O‐dealkylation and glutathione (GSH) conjugation were all involved in the metabolism of pyrotinib in hepatocytes. The most predominant metabolic route was identified as GSH conjugation (M5). Conclusions: This study generated valuable metabolite profiles of pyrotinib in several species, which will aid in the understanding of the drug's disposition in various species and in evaluating the contribution of metabolites to overall effectiveness and toxicity of pyrotinib. [ABSTRACT FROM AUTHOR]

Since Dr. Carl Salomon proposed the well-known hypothesis on cutting temperatures in 1931, the debate on the hypothesis has never stopped. It shows that evolutions of temperatures with the increase of cutting speed measured at different points are different. From the tool wear and surface integrity point of view, this paper focuses on the evolutions of chip temperature (Chip temp.), tool-chip contact temperature (T-C temp.), and tool-workpiece contact temperature (T-W temp.) with the increase of cutting speed from low (100 m/min) to very high (7000 m/min). First, the cutting heat generation and the temperature increment in machining are theoretically analyzed. Then the influences of chip shape and mechanical property variations with the increase of cutting speed on the temperatures are analyzed. Finally, the cutting temperatures are semiquantitatively derived from chip colors and other heat characteristics in the chip and cutting tool obtained in cutting experiments: evolutions of Chip temp., T-C temp., and T-W temp. with the increase of cutting speed are presented based on the experiment results. The influence of chip shape and temperature variation on tool wear are also discussed. [ABSTRACT FROM AUTHOR]

Background: Genotyping by sequencing (GBS) still has problems with missing genotypes. Imputation is important for using GBS for genomic predictions, especially for low depths, due to the large number of missing genotypes. Minor allele frequency (MAF) is widely used as a marker data editing criteria for genomic predictions. In this study, three imputation methods (Beagle, IMPUTE2 and FImpute software) based on four MAF editing criteria were investigated with regard to imputation accuracy of missing genotypes and accuracy of genomic predictions, based on simulated data of livestock population. Results: Four MAFs (no MAF limit, MAF ≥ 0.001, MAF ≥ 0.01 and MAF ≥ 0.03) were used for editing marker data before imputation. Beagle, IMPUTE2 and FImpute software were applied to impute the original GBS. Additionally, IMPUTE2 also imputed the expected genotype dosage after genotype correction (GcIM). The reliability of genomic predictions was calculated using GBS and imputed GBS data. The results showed that imputation accuracies were the same for the three imputation methods, except for the data of sequencing read depth (depth) = 2, where FImpute had a slightly lower imputation accuracy than Beagle and IMPUTE2. GcIM was observed to be the best for all of the imputations at depth = 4, 5 and 10, but the worst for depth = 2. For genomic prediction, retaining more SNPs with no MAF limit resulted in higher reliability. As the depth increased to 10, the prediction reliabilities approached those using true genotypes in the GBS loci. Beagle and IMPUTE2 had the largest increases in prediction reliability of 5 percentage points, and FImpute gained 3 percentage points at depth = 2. The best prediction was observed at depth = 4, 5 and 10 using GcIM, but the worst prediction was also observed using GcIM at depth = 2. Conclusions: The current study showed that imputation accuracies were relatively low for GBS with low depths and high for GBS with high depths. Imputation resulted in larger gains in the reliability of genomic predictions for GBS with lower depths. These results suggest that the application of IMPUTE2, based on a corrected GBS (GcIM) to improve genomic predictions for higher depths, and FImpute software could be a good alternative for routine imputation. [ABSTRACT FROM AUTHOR]

Due to the low rigidity of the boring bar with a large length-to-diameter ratio, chatter easily occurs during deep hole boring. In this paper, an ultrasonic vibration boring bar with a length-to-diameter ratio greater than 10 is designed to suppress the chatter during the boring operation of deep holes. First, the dynamic model of the boring operation is built to guide the design of the ultrasonic vibration boring bar. Then, the optimal design of structure parameter of the ultrasonic vibration boring bar is performed by the finite element method, and then the optimized boring bar is manufactured. Finally, the vibration performance test and cutting experiments are carried out to verify the machining capability of the bar. The experimental results show that the ultrasonic vibration boring bar can reduce the cutting force by about 35%, improve the system stability, and increase the quality of the relative machined surface by about 43%, which demonstrate the feasibility of chatter suppression of the developed ultrasonic vibration boring bar. [ABSTRACT FROM AUTHOR]

The distribution of Asian ancestry in the genome of Danish Duroc pigs was investigated using whole‐genome sequencing data from European wild boars, Danish Duroc, Chinese Meishan and Bamaxiang pigs. Asian haplotypes deriving from Meishan and Bamaxiang occur widely across the genome. Signatures of selection on Asian haplotypes are common in the genome, but few of these haplotypes have been fixed. By defining 50‐kb windows with more than 50% Chinese ancestry, which did not exhibit extreme genetic differentiation between Meishan and Bamaxiang as candidate regions, the enrichment of quantitative trait loci in candidate regions supports that Asian haplotypes under selection play an important role in contributing genetic variation underlying production, reproduction, meat and carcass, and exterior traits. Gene annotation of regions with the highest proportion of Chinese ancestry revealed genes of biological interest, such as NR6A1. Further haplotype clustering analysis suggested that a haplotype of Chinese origin around the NR6A1 gene was introduced to Europe and then underwent a selective sweep in European pigs. Besides, functional genes in candidate regions, such as AHR and PGRMC2, associated with fertility, and SAL1, associated with meat quality, were identified. Our results demonstrate the contribution of Asian haplotypes to the genomes of European pigs. Findings herein facilitate further genomic studies such as genomewide association study and genomic prediction by providing ancestry information of variants. [ABSTRACT FROM AUTHOR]

Background: Eurasian pigs have undergone lineage admixture throughout history. It has been confirmed that the genes of indigenous pig breeds in China have been introduced into Western commercial pigs, providing genetic materials for breeding Western pigs. Pigs in Taihu Lake region (TL), such as the Meishan pig and Erhualian pig, serve as typical representatives of indigenous pig breeds in China due to their high reproductive performances. These pigs have also been imported into European countries in 1970 and 1980 s. They have played a positive role in improving the reproductive performances in European commercial pigs such as French Large White pigs (FLW). However, it is currently unclear if the lineage of TL pigs have been introgressed into the Danish Large White pigs (DLW), which are also known for their high reproductive performances in European pigs. To systematically identify genomic regions in which TL pigs have introgressed into DLW pigs and their physiological functions, we collected the re-sequencing data from 304 Eurasian pigs, to identify shared haplotypes between DLW and TL pigs. Results: The findings revealed the presence of introgressed genomic regions from TL pigs in the genome of DLW pigs indeed. The genes annotated within these regions were found to be mainly enriched in neurodevelopmental pathways. Furthermore, we found that the 115 kb region located in SSC16 exhibited highly shared haplotypes between TL and DLW pigs. The major haplotype of TL pigs in this region could significantly improve reproductive performances in various pig populations. Around this genomic region, NDUFS4 gene was highly expressed and showed differential expression in multiple reproductive tissues between extremely high and low farrowing Erhualian pigs. This suggested that NDUFS4 gene could be an important candidate causal gene responsible for affecting the reproductive performances of DLW pigs. Conclusions: Our study has furthered our knowledge of the pattern of introgression from TL into DLW pigs and the potential effects on the fertility of DLW pigs. [ABSTRACT FROM AUTHOR]

• An empirical fracture model based on the maximum strain principle is proposed. • The new model takes into account the embrittlement effect of high strain rate, and. • Can predict the ductile fracture of materials in the full range of strain rate. At different deformation rates, a ductile material may fail by isothermal deformation fracture, thermoplastic shear instability, or even brittle fracture. The failure mode transition at sound speed deformation rate has not been well described. This paper aims to establish a new fracture model which considers the strain rate embrittlement effect (SREE) at the sound speed deformation rate, and can be used to predict the failure of the material in a large range of strain rate. Taking pure iron DT 8 as the experimental material, impact tests of pure iron specimens under different stress states, strain rates, and temperatures were carried out. Fracture strains under different stress states, strain rates, and temperatures were obtained. The strain rate was increased to 227450/s (5.36/s in log10) to obtain the ductile–brittle transition point. A new fracture model is proposed to describe the evolution of fracture strain over the wide range of strain rate. The new proposed model is experimentally validated and compared with the J-C failure model. It shows the new proposed fracture model can predict the ductile fracture behavior of a ductile material in the full strain rate range, and capture the failure mode transition at the sound speed deformation rate of a material. [ABSTRACT FROM AUTHOR]

Reliability of estimated breeding values (EBV) depends on amount of information in both phenotypic data and pedigree data. This study investigated the impact of phenotypic information of previous generations and depth of pedigree on estimates of genetic parameters and breeding values in populations of polytocous animals such as pig. Three populations which mimicked pig populations were generated. The animals were selected on a selection index including two traits ( h 2 =0.35 for trait 1 and h 2 =0.10 for trait 2). Variance components and breeding values were estimated using different phenotypic data and pedigree data which cover different numbers of previous generations. Impact of phenotypic information of previous generations and depth of pedigree on EBV was evaluated by reliability of EBV for animals in the last generation (as candidates for breeding). Phenotypic data or pedigree data covering various numbers of previous generations led to different estimates of additive genetic variance (larger variance when earlier generations were included), especially for trait 1, because conceptual base populations were different in different data sets. Information from previous generations was more important for reliability of EBV of trait 2 than that of trait 1, and the contribution of previous phenotypic information to reliability of EBV was larger in the population with smallest sib group than the population with the largest sib group. According to the current study, phenotypic data including recent three to five generations and pedigree data added one to three ancestral generations will lead to asymptotic maximum reliability of EBV for animals in current population, dependent on population structure and heritability of trait. The results indicate: (1) In general, three generations of records plus two ancestral generations in pedigree is enough for predicting breeding values with regard to accuracy of EBV; (2) Variance components used for genetic evaluation should be estimated from the data set that is consistent with the data set for predicting breeding values with regard to conceptual base population; (3) In order to increase reliability of EBV in a polytocous animal population such as pig, the efficient approach is to measure the animals available within generation as many as possible so as to fully use information from sibs, instead of more data from early generations. [ABSTRACT FROM AUTHOR]

Reproductive traits of dairy cattle are bound to the actual efficiency of farm operation, which therefore show great economic importance. Among them, some traits were deemed to be simultaneously affected by service sire and mating cow. Service sires are proved to play an important role in reproduction process of cows. However, limited study explored the genetic effect of service sire (GESS), let alone the genomic prediction of this effect. In the present study, 2244 genotyped bulls together with phenotypic records were used to predict the GESS on conception rate, 56‐day non‐return rate, calving ease, stillbirth and gestation length. The feasibilities of multi‐step genomic best linear unbiased predictor (msGBLUP) and single‐step genomic best linear unbiased predictor (ssGBLUP) were investigated under different scenarios, that is, different marker densities and validation population. The predictive accuracies and unbiasedness for GESS ranged from 0.159 to 0.647 and from 0.202 to 2.018, respectively, when validated on young bulls, while the accuracies and unbiasedness ranged from 0.409 to 0.802 and 0.333 to 1.146 when validated on random split data sets. It is feasible to predict GESS on reproductive traits by using a linear mixed model and genomic data, and high‐density marker panel had limited contribution to the prediction. This research investigated the potential factors that influence the genomic prediction of GESS on reproductive traits and indicated the possibility of genomic selection on GESS, both in ideal and practical circumstances. [ABSTRACT FROM AUTHOR]

Saw-tooth chip changes from macroscopically continuous ribbon to separated segments with the increase of cutting speed. The aim of this study is to find the correlations between chip morphology and machined surface micro-topography at different chip serration stages encountered in high speed cutting. High strength alloy steel AerMet100 was employed in orthogonal cutting experiments to obtain chips at different serration stages and corresponding machined surfaces. The chips and machined surfaces obtained were then examined with optical microscope (OM), scanning electron microscope (SEM), and white light interferometer (WLI). The result shows that chip serration causes micro-waves on machined surface, which increases machined surface roughness. However, wave amplitudes (surface roughness) at different serration stages are different. The principal factor influencing wave amplitude is the thickness of the sawed segment (tooth) of saw-tooth chip. With cutting parameters in this study, surface roughness contributed by chip serration ranges from 0.39 μm to 1.85 μm. This may bring on serious problems in the case of trying to replace grinding with high-speed cutting in rough machining. Some suggestions have been proposed to control the chip serration-caused surface roughness in high-speed cutting based on the results of the current study. [ABSTRACT FROM AUTHOR]

[Display omitted] • Chips produced in cutting of pure iron turns into grains at cutting speed 8000 m/min. • Above 8000 m/min chips are formed by transgranular and intergranular fractures. • High ductile metals can be fabricated brittlely with a high deformation rate. Many materials have high-strain-rate-embrittlement effect (HSREE). This study tries to find weather the HSREE takes place in the high-strain rate deformation of a high ductile material pure iron DT8 to assess the possibility to cut the pure iron in its brittle state. Orthogonal high-speed cutting experiments were carried out with the highest cutting speed up to 9000 m/min. Chip formation by brittle fracture mechanism was captured when the cutting speed is higher than 8000 m/min. Brittle fracture characteristics, including transgranular and intergranular fracture morphologies in the chips at 8000 m/min show the pure iron becomes completely brittle at cutting speed of 8000 m/min. The result shows that it is possible to cut the high ductile material pure iron in its brittle state to avoid the problems incurred by its high ductility. [ABSTRACT FROM AUTHOR]

Saw tooth chip is a typical characteristic encountered in high-speed machining. It consists of nearly undeformed segments and highly sheared concentrated shear bands. However, no consensus on the formation of the concentrated shear band has been reached though several saw tooth chip formation models have been built. In this paper, the concentrated shear band formation procedure is analyzed based on a new proposed saw tooth chip formation model. Cutting experiments have been conducted to validate the proposed mode. It shows that the plastic side flow and elastic compression of the uncut chip are crucial for the concentrated shear band formation. The localized shear at the inner end (tool tip side) of the primary shear plane firstly takes place under the indentation of cutting tool. Then, the second localized shear is produced at the outer end (free surface side) of the primary shear plane due to stress concentration there, after which the whole concentrated shear band forms. The stress transition at the outer end of the primary shear plane makes the second localized shear easier evolve into cracks. Influences of material brittleness and cutting speed on initiation and propagation of the concentrated shear band are also analyzed. [ABSTRACT FROM AUTHOR]

For genomic prediction of crossbred animals, models that account for the breed origin of alleles (BOA) in marker genotypes can allow the effects of marker alleles to differ depending on their ancestral breed. Previous studies have shown that genomic estimated breeding values for crossbred cows can be calculated using the marker effects that are estimated in the contributing pure breeds and combined based on estimated BOA in the genotypes of the crossbred cows. In the presented study, we further exploit the BOA information for improving the prediction of genomic breeding values of crossbred dairy cows. We investigated 2 types of BOA-derived breed proportions: global breed proportions, defined as the proportion of marker alleles assigned to each breed across the whole genome; and local breed proportions (LBP), defined as the proportions of alleles on chromosome segments which were assigned to each breed. Further, we investigated 2 BOA-derived measures of heterozygosity for the prediction of total genetic value. First, global breed heterozygosity, defined as the proportion of marker loci that have alleles originating in 2 different breeds over the whole genome. Second, local breed heterozygosity (LBH), defined as proportions of marker loci on chromosome segments that had alleles originating in 2 different breeds. We estimated variance related to LBP and LBH on the remaining variation after accounting for prediction with solutions from the genomic evaluations of the pure breeds and validated alternative models for production traits in 5,214 Danish crossbred dairy cows. The estimated LBP variances were 0.9, 1.2, and 1.0% of phenotypic variance for milk, fat, and protein yield, respectively. We observed no clear LBH effect. Cross-validation showed that models with LBP effects had a numerically small but statistically significantly higher predictive ability than models only including global breed proportions. We observed similar improvement in accuracy by the model having an across crossbred residual additive genetic effect, accounting for the additive genetic variation that was not accounted for by the solutions from purebred. For genomic predictions of crossbred animals, estimated BOA can give useful information on breed proportions, both globally in the genome and locally in genome regions, and on breed heterozygosity. [ABSTRACT FROM AUTHOR]

For genomic prediction of crossbred animals, models that account for the breed origin of alleles (BOA) in marker genotypes can allow the effects of marker alleles to differ depending on their ancestral breed. Previous studies have shown that genomic estimated breeding values for crossbred cows can be calculated using the marker effects that are estimated in the contributing pure breeds and combined based on estimated BOA in the genotypes of the crossbred cows. In the presented study, we further exploit the BOA information for improving the prediction of genomic breeding values of crossbred dairy cows. We investigated 2 types of BOA-derived breed proportions: global breed proportions, defined as the proportion of marker alleles assigned to each breed across the whole genome; and local breed proportions (LBP), defined as the proportions of alleles on chromosome segments which were assigned to each breed. Further, we investigated 2 BOA-derived measures of heterozygosity for the prediction of total genetic value. First, global breed heterozygosity, defined as the proportion of marker loci that have alleles originating in 2 different breeds over the whole genome. Second, local breed heterozygosity (LBH), defined as proportions of marker loci on chromosome segments that had alleles originating in 2 different breeds. We estimated variance related to LBP and LBH on the remaining variation after accounting for prediction with solutions from the genomic evaluations of the pure breeds and validated alternative models for production traits in 5,214 Danish crossbred dairy cows. The estimated LBP variances were 0.9, 1.2, and 1.0% of phenotypic variance for milk, fat, and protein yield, respectively. We observed no clear LBH effect. Cross-validation showed that models with LBP effects had a numerically small but statistically significantly higher predictive ability than models only including global breed proportions. We observed similar improvement in accuracy by the model having an across crossbred residual additive genetic effect, accounting for the additive genetic variation that was not accounted for by the solutions from purebred. For genomic predictions of crossbred animals, estimated BOA can give useful information on breed proportions, both globally in the genome and locally in genome regions, and on breed heterozygosity. [ABSTRACT FROM AUTHOR]

Abstract: In this paper cutting experiments of AerMet100 (52 HRC) using nano TiAlN-coated carbide tools with cutting speed from 250m/min to 7000m/min are carried out. The cutting tool wear characteristics under ultra-high cutting speeds are examined and the corresponding mechanisms are analyzed. The focus is put on the tool wear characteristics and mechanisms at cutting speed above 500m/min. The influences of cutting temperature and workpiece dynamic mechanical properties on tool wear are discussed. The results show that the tool wear mechanism is highly influenced by cutting temperature and workpiece mechanical properties. At cutting speed of 500m/min the dominate wear mechanism is micro chipping and fracture due to the cutting force vibration and cold welding of contacting materials between cutting tool and workpiece. At higher cutting speed from 1000m/min to 7000m/min the predominant tool wear mechanisms are abrasion, adhesion, and fracture due oxidation, and thermal softening, and grooving by hard grains. The roughness of tool flank at this cutting stage decreases with the increase of cutting speed due to the high thermal softening. The increase of workpiece material brittleness with the increase of cutting speed lowers the elastic rebound of machined surface and reduces the tool wear rate. [Copyright &y& Elsevier]

The contact stress and heating effect between the cutting tool and workpiece in metal machining is symmetrical. However, the symmetry may be destroyed by changes in the workpiece material mechanical properties, such as ductility. The goal of this study is to reveal the wear characteristics of the cutting tool in machining a ductile metal with the cutting speed at which the metal is embrittled by the high-strain-rate-embrittle effect (HSREE). Orthogonal high-speed turning experiments were carried out. Pure iron type DT8 was cut at different cutting speeds, ranging from 1000 m/min to 9000 m/min. The shape and morphology of the chips obtained in the experiment were observed and analyzed by optical microscope and scanning electron microscope (SEM). Tool wear characteristics at different cutting speeds were observed. It shows that the pure iron becomes completely brittle when the cutting speed is higher than 8000 m/min. On the rake face, the coating of the cutting tool bursts apart and peels off. A matrix crack originates in the cutting edge or rake face and extends to the flank face of the cutting tool. The effects of HSREE on the tool wear is discussed. The findings of this study are helpful for choosing a suitable tool for brittle cutting of the ductile metal pure iron with very high cutting speed and solving the problems in machining due to its high ductility and high stickiness. [ABSTRACT FROM AUTHOR]

The stability prediction is usually used to avoid the unstable machining in milling process. According to the Lagrange-Simpson hybrid interpolation scheme, this paper improves a numerical integration method (NIM) to perform the milling chatter prediction accurately and efficiently. Firstly, the higher-order numerical integral formulas (NIFs) are constructed based on the Lagrange polynomial. Thus, the third-order and fourth-order NIMs are built and investigated respectively. Then, to improve the calculated performance of the NIMs, the Simpson scheme is introduced to decrease the local discretization error. Finally, the comparisons among the built NIMs and the existing discretization methods are carried out by calculating the convergence rate and the stability boundaries. Compared to the third-order NIM and the third-order full-discretization method, the proposed second-order Lagrange-Simpson NIM shows the better computational performance. [ABSTRACT FROM AUTHOR]

Genomic predictions have been applied for dairy cattle for more than a decade with great success, but genomic estimated breeding values (GEBV) are not widely available for crossbred dairy cows. The large reference populations already in place for genomic evaluations of many pure breeds makes it interesting to use the accurate solutions, in particular the estimated marker effects, from these evaluations for calculation of GEBV for crossbred heifers and cows. Effects of marker alleles in crossbred animals can depend on breed origin of the alleles (BOA). Therefore, our aim was to investigate if reliable GEBV for crossbred dairy cows can be obtained by combining estimated marker effects from purebred evaluations based on BOA. We used data on 5,467 Danish crossbred dairy cows with contributions from Holstein, Jersey, and Red Dairy Cattle breeds. We assessed BOA assignment on their genotypes and found that we could assign 99.3% of the alleles to a definite breed of origin. We compared GEBV for 2 traits, protein yield and interval between first and last insemination of cows, with 2 models that both combine estimated marker effects from the genomic evaluations of the pure breeds: a breed of origin model that accounts for BOA and a breed proportion model that only accounts for genomic breed proportions in the crossbred animals. We accounted for the difference in level between the purebred evaluations by including intercepts in the models based on phenotypic averages. The predictive ability for protein yield was significantly higher from the breed of origin model, 0.45 compared with 0.43 from the breed proportion model. Furthermore, for the breed proportion model, the GEBVs had level bias, which made comparison across groups with different breed composition skewed. We therefore concluded that reliable genomic predictions for crossbred dairy cows can be obtained by combining estimated marker effects from the genomic evaluations of purebreds using a model that accounts for BOA. [ABSTRACT FROM AUTHOR]

Mo2NiB2 is a kind of cermet with excellent mechanical properties, stable chemical properties, and excellent corrosion resistance and is often used in wear‐resistant application fields, such as injection molding machine parts, can making tools and hot copper extruding dies. The brittleness of Mo2NiB2‐based cermets limits their wide application. Mo2NiB2‐based cermets were prepared by the vacuum sintering method, the effect of SiC whiskers (SiCw) on the microstructure and mechanical properties of cermets was investigated, and the toughening mechanism of SiCw on cermets was further discussed. The results indicate that with increasing SiCw content, the indentation fracture toughness (KIC), transverse fracture strength (TRS), and Vickers hardness (HV) of the cermets first increase and then decrease. The HV, TRS, and indentation fracture toughness of Mo2NiB2‐based cermets with 0.5 wt% SiCw are 1 113 HV, 1 620 MPa, and 27.97 MPa·m1/2, respectively, which are 16.8%, 22.7%, and 25% higher than those without SiCw. In the sliding friction tests, Mo2NiB2‐based cermets with 0.5 wt% SiCw have the smallest friction coefficient, low wear rate, and high wear resistance. SEM observation and analysis of the crack path and fracture surface showed that the toughening mechanism is whisker bridging, crack deflection, microcrack toughening, and whisker pull‐out. The results indicate that the addition of 0.5 wt% SiCw can effectively improve the mechanical properties of Mo2NiB2‐based cermets and further expand the application space of Mo2NiB2‐based cermets. [ABSTRACT FROM AUTHOR]

The difficulty or high cost to register pedigree and the presence of genotype by environment interaction (G×E) are the factors limiting conventional selective breeding in aquaculture. The limitation could be overcome by genomic selection. The objective of this study was to investigate the impact of phenotypic information and composition of reference population on genomic prediction in aquaculture under the presence of G×E, and the impact of genotyping strategy for selection candidates on genetic progress. The study was based on simulated data mimicking a rainbow trout population under G×E where genetic correlation between breeding environment and commercial production environment was 0.8, 0.5 or 0.2. Different scenarios of reference population were investigated, with regard to reference individuals from breeding population or production population, reference individuals were a random sample or a selected sample of top fish, and the phenotypic performance of the reference individuals were measured in breeding environment or in production environment. These scenarios were assessed on accuracy and unbiasedness of predicted breeding value for performance in commercial production environment. The results showed that genomic prediction greatly increased accuracy of selection, compared with conventional pedigree-based selection. Reference population comprising top individuals led to low accuracy and serious bias of genomic prediction. Accuracies of breeding values for performance in production environment predicted based on phenotypic information from breeding farm were low when genetic correlation between breeding and production environments was less than 0.8. With records of performance measured in production farm, reference population comprising individuals from breeding population gave higher prediction accuracy than the reference individuals from production population did. In addition, preselecting candidates from the breeding population for genotyping led to larger selection response than randomly genotyping candidates. These results indicate that genomic selection is feasible and promising in fish breeding under the presence of G×E. It is a good strategy to use a reference population comprising individuals randomly sampled from breeding population but reared in commercial production farm to get phenotypic records (RanBC in the context). Such a reference population is representative of the whole population, have a close relationship with candidates, and lead to a direct selection for performance in commercial production environment. In the situation of limited cost for genotyping selection candidates, genotyping top selection candidates is a good strategy since it can realize high selection intensity. • This study shows the benefit of genomic prediction in fish under the presence of genotype by environment interaction. • The phenotypic information and composition of reference population has a large impact on genomic prediction. • The desired reference is a random sample from breeding population with phenotypic records in target production environment. • In the limitation of cost for genotyping selection candidates, genotyping top ones is a good strategy. [ABSTRACT FROM AUTHOR]

Three-axis computer numerical control machining centers are commonly used in machining due to their simple operations. When machining curved surfaces, the 3-axis CNC machining centers use interpolation line segment to fit the curved surfaces. The quality of the machined surface is affected by the length of the interpolation line segment. Sharp corners are formed at the junction of straight segments. The appearance of sharp corners will lead to increased stress concentration. To study the relationship between machined surface quality and interpolation straight line, this paper establishes the mathematical model of surface topography in ball-end milling multi-curved surfaces by a 3-axis milling center with considering the acceleration and deceleration controls. Based on the surface topography model, the stress concentration factor is analyzed in machining curved surfaces with different lengths of interpolation lines. The results show that the stress concentration factor decreases with the increase of the central angle when the length of interpolation lines and the radius of curvature are kept in constant, while decreases with the increase of the radius of curvature when the length of the interpolation lines and the central angle are held on. Moreover, the stress concentration factor increases as the length of the interpolation lines increases when the radius of curvature and the central angle are kept in constant. A method for selecting proper length of interpolation lines based on the stress concentration is proposed. In addition, the quality of the machined surfaces can be improved through the optimization of the tool path. [ABSTRACT FROM AUTHOR]

As an important transmission component, the spur gear has been widely used in automobiles and various mechanical equipment. However, spur gears are usually produced by the hobbing and shaving, which inevitably reduces the service strength and service life of the gear. In this paper, the one-step punching forming process of spur gear is presented. Compared with the traditional gear machining process, the process not only avoids the destruction of the metal flow line but significantly decreases the material cost. The effect of tooth filling and equivalent strain accumulation on gear forming quality was investigated by finite element simulation. The effects of upper die punching speed, lower die preheating temperature, and friction coefficient on lower die wear during forming were studied by response surface method. The optimum process parameters of punching of spur gear were a lower die preheating temperature of 280 ℃, friction coefficient of 0.27, and upper die feed speed of 8.3 mm/s, respectively. It is predicted that about 110,000 gears can be produced before the wear failure of the lower die. On the basis of the finite element simulation results, the gear punching experiment is performed. The experimental results are in good agreement with the simulation results, and the metal flow line at the tooth is uniform and continuous, which verifies the reliability of the one-step punching process. [ABSTRACT FROM AUTHOR]

During subsequent machining of laser cladded workpiece, the stress transferred in depth direction is different from the conventional cast workpiece due to the geometrical discontinuity, resulting in the stress difference and strain discontinuity at the interface between the cladding layer and substrate. Distinguishing from the traditional finite element method model, this paper establishes a model with an inclined interface to investigate the thickness ratio, i.e., the ratio of the removal thickness in subsequent machining to cladding thickness on the machining-induced stress and strain. The results show that the maximum thickness ratio is 0.352 when the removal thickness is 0.1 mm. The change in interfacial shear stress energy dissipation due to interfacial inclination makes this result 22.8% lower than a traditional model with a horizontal interface. With the help of the presented model, the effect of removal thickness on machining-induced stress and strain evolution was investigated. The results show that an increase in the removal thickness will lead to an increase in machining-induced stress and strain. The stress difference and strain increment at the interface increase proportionally with the removal thickness, implying that variations in removal thickness will have a consequential impact on the maximum thickness ratio. Thus, the interaction of material removal thickness and thickness ratio on PEEQ increment at the interface was further analyzed. The response surface results indicate that an increase in the removal thickness leads to a corresponding increase in the maximum thickness ratio, albeit with a minor degree of influence. Therefore, the challenge of fixing the maximum thickness ratio in actual machining due to multi-step processes can be resolved through micro-adjustments. Simultaneously, in engineering applications, workpiece surface defects exhibit varying depths and require different removal amounts after cladding. This study provides further theoretical guidance for repairing and remanufacturing surface defects with diverse depths. [ABSTRACT FROM AUTHOR]

Icelandic Cattle is a local dairy cattle breed in Iceland. With about 26,000 breeding females, it is by far the largest among the indigenous Nordic cattle breeds. The objective of this study was to investigate the feasibility of genomic selection in Icelandic Cattle. Pedigree-based best linear unbiased prediction (PBLUP) and single-step genomic best linear unbiased prediction (ssGBLUP) were compared. Accuracy, bias, and dispersion of estimated breeding values (EBV) for milk yield (MY), fat yield (FY), protein yield (PY), and somatic cell score (SCS) were estimated in a cross validation-based design. Accuracy (⁠ r ^ ⁠) was estimated by the correlation between EBV and corrected phenotype in a validation set. The accuracy (⁠ r ^ ⁠) of predictions using ssGBLUP increased by 13, 23, 19, and 20 percentage points for MY, FY, PY, and SCS for genotyped animals, compared with PBLUP. The accuracy of nongenotyped animals was not improved for MY and PY, but increased by 0.9 and 3.5 percentage points for FY and SCS. We used the linear regression (LR) method to quantify relative improvements in accuracy, bias (⁠ Δ ^ ⁠), and dispersion (⁠ b ^ ⁠) of EBV. Using the LR method, the relative improvements in accuracy of validation from PBLUP to ssGBLUP were 43%, 60%, 50%, and 48% for genotyped animals for MY, FY, PY, and SCS. Single-step GBLUP EBV were less underestimated (⁠ Δ ^ ⁠), and less overdispersed (⁠ b ^ ⁠) than PBLUP EBV for FY and PY. Pedigree-based BLUP EBV were close to unbiased for MY and SCS. Single-step GBLUP underestimated MY EBV but overestimated SCS EBV. Based on the average accuracy of 0.45 for ssGBLUP EBV obtained in this study, selection intensities according to the breeding scheme of Icelandic Cattle, and assuming a generation interval of 2.0 yr for sires of bulls, sires of dams and dams of bulls, genetic gain in Icelandic Cattle could be increased by about 50% relative to the current breeding scheme. [ABSTRACT FROM AUTHOR]

The hardness and toughness of regenerated cemented carbides, in general, are contradictory. Therefore, it is critical to explore regenerated cemented carbides with both high hardness and high toughness. In this study, regenerated WC‐8‐wt% Co cemented carbide with SiC nanowhisker were prepared by low‐pressure sintering. The influence of SiCw contents on the microstructure and mechanical properties of regenerated WC‐8‐wt% Co cemented carbide was investigated. The results indicated that the hardness, density, flexural strength, and fracture toughness of regenerated cemented carbide first increased and then decreased with the addition of SiCw. The Vickers hardness, density, flexural strength, and fracture toughness could reach 1575 HV, 14.6 g/cm3, 2204 MPa, 16.85 MPa·m1/2, respectively, with SiCw content 0.5 wt%, which were increased by 14.4%, 0.7%, 12.2%, and 17.3%, respectively, when compared with the regenerated cemented carbide without SiCw. The lowest friction coefficient and the best wear resistance could be also reached when 0.5‐wt% SiCw was added. The fracture mechanism of the regenerated cemented carbide contained both transgranular and intergranular fracture through the microscopic observation of fracture surface via scanning electron microscope. [ABSTRACT FROM AUTHOR]

The elite bull plays an extremely important role in the genetic progression of the dairy cow population. The previous results indicated the potential positive relationship of large scrotal circumference (SC) with improved semen volume, concentration, and motility. In order to improve bull's semen quantity and quality by selection, it is necessary to estimate the genetic parameters of semen traits and their correlations with other conformation traits such as SC that could be used for an indirect selection. In this study, the genetic parameters of seven semen traits (n = 66,260) and nine conformation traits (n = 3,642) of Holstein bulls (n = 453) were estimated by using the bivariate repeatability animal model with the average information-restricted maximum likelihood (AI-REML) approach. The results showed that the estimated heritabilities of semen traits ranged from 0.06 (total number of motile sperm, TNMS) to 0.37 (percentage of abnormal sperm, PAS) and conformation traits ranged from 0.23 (pin width, PW) to 0.69 (hip height, HH). The highest genetic correlations were found between semen volume per ejaculation (SVPE), semen concentration per ejaculation (SCPE), total number of sperm (TNS), and TNMS traits that were 0.97, 0.98, 1.00, and 0.99, respectively. Phenotypic correlations between SC and SVPE, SCPE, TNS, and TNMS were 0.35, 0.35, 0.48, and 0.42, respectively. In summary, the moderate or high heritability of semen traits indicates that genetic improvement of semen quality by selection is feasible, where SC could be a useful trait for indirect selection or as correlated information to improve semen quantity and production in the practical bull breeding programs. [ABSTRACT FROM AUTHOR]

Burnishing is a way to realize surface strengthening by plastic deformation behavior. How to characterize the severe plastic deformation in subsequent burnishing process and how to make the severe plastic deformation more reasonable and effective for the improvement of machined surface integrity have become key problems. This work studied the relationships among plastic deformation behaviors, strain energy, and improved surface integrity ratio in subsequent burnishing with different initial surface conditions. To achieve this purpose, a numerical strain energy model was first established and then utilized to analyze the material flow behaviors and plastic deformation mechanism. The results indicated that the strain energy density decreases first and then increases, while the strain energy and corresponding energy efficiency gradually increases with the increase of turning feed, i.e., surface residue. As a result, the plastic deformation in subsequent burnishing first increases and then decreases with the increase of surface residue and reached the severest when the turning feed is 0.35 mm/r. Even though the turning-induced surface integrity can be further improved by the subsequent burnishing, the improved surface integrity ratio showed a downward trend with the increase of the turning feed, which ever increased the machining efficiency for the process chain. It is expected to improve both the energy efficiency ratio and improved surface integrity ratio, so as to improve the sustainability of the subsequent burnishing process. [ABSTRACT FROM AUTHOR]

Diamond-like carbon (DLC)-coated tools are suitable for the machining of various aluminum alloys, graphite, and other non-ferrous metals. The shortcomings of DLC-coated tools such as high internal residual stress, low toughness, and poor adhesion strength limit their application. In order to reveal the mechanical and cutting performance of DLC-coated tools, a DLC monolayer coating, Cr/CrN/DLC composite coating, and Cr/W-DLC/DLC composite coating had been prepared on the cemented carbide cutting tools. The influences of transition interlayer on the microstructure and mechanical properties of DLC coatings were analyzed. Tool lives, wear mechanism, and machined surface roughness obtained with uncoated cemented carbide tool, DLC monolayer–coated tool, and Cr/x/DLC-coated tool during the machining of Al-Si alloys were investigated. Compared with DLC monolayer coating, the strength ratio (ID/IG) of the DLC composite coatings with Cr/x transition structure was improved, while the sp3 covalent bond contents was decreased. The results show that the adhesion strength and toughness of the Cr/x/DLC composite coating were enhanced, and the residual stress was greatly reduced. The cutting tests further indicate that the DLC coating significantly improved the tool life. Based on comprehensive evaluation, the Cr/W-DLC/DLC composite coating has the highest adhesion, highest toughness, the lowest residual stress, and the longest tool life, and it is suitable for the machining of non-ferrous metal. [ABSTRACT FROM AUTHOR]

This paper investigates the effect of turning process on surface quality and corrosion behaviors of laser cladded coatings on the 1045 steel. Corrosion resistance of the 1045 steel is improved by laser cladded Fe−Cr−Ni coatings. The as‐cladded coating behaves nobler and more resistant to corrosion compared to the 1045 steel substrate. By using turning as a finish process, surface roughness Ra of the laser cladded coating is decreased to 0.517 µm to meet the surface roughness requirement (i.e., Ra ≤ 0.8 µm) of a single‐telescopic hydraulic column. Also, surface defects including laps, cavities, and adhered material particles occur on the cladded coatings after machining. The machined coatings exhibit comparable polarization resistance compared to the as‐cladded condition, and the polarization resistance of the machined surface increases with feed rate increasing. The corrosion pits show sensitivity on feed marks induced by machining. This concentrated distribution of corrosion pits is a result of the fluctuation of local electron work function (EWF), which promotes the formation of local corrosion cells in adjacency to feed marks. [ABSTRACT FROM AUTHOR]

Simple Summary: The size of the reference population is critical to the accuracy of genomic prediction. In addition, joining the reference populations from different breeding organizations is a convenient and effective method by which to enlarge reference populations. By adding the Nordic Holstein reference population to the Chinese Holstein reference population, we found that the accuracy of genomic prediction in the Chinese Holstein population was improved substantially for the traits with high or moderate genetic correlation between the two populations; however, the low-genetic-correlation traits did not improve. These findings are important for the purposes of multi-country joint genomic evaluation. The size of the reference population is critical in order to improve the accuracy of genomic prediction. Indeed, improving genomic prediction accuracy by combining multinational reference populations has proven to be effective. In this study, we investigated the improvement of genomic prediction accuracy in seven complex traits (i.e., milk yield; fat yield; protein yield; somatic cell count; body conformation; feet and legs; and mammary system conformation) by combining the Chinese and Nordic Holstein reference populations. The estimated genetic correlations between the Chinese and Nordic Holstein populations are high with respect to protein yield, fat yield, and milk yield—whereby these correlations range from 0.621 to 0.720—and are moderate with respect to somatic cell count (0.449), but low for the three conformation traits (which range from 0.144 to 0.236). When utilizing the joint reference data and a two-trait GBLUP model, the genomic prediction accuracy in the Chinese Holsteins improves considerably with respect to the traits with moderate-to-high genetic correlations, whereas the improvement in Nordic Holsteins is small. When compared with the single population analysis, using the joint reference population for genomic prediction in younger animals, results in a 2.3 to 8.1 percent improvement in accuracy. Meanwhile, 10 replications of five-fold cross-validation were also implemented in order to evaluate the performance of joint genomic prediction, thereby resulting in a 1.6 to 5.2 percent increase in accuracy. With respect to joint genomic prediction, the bias was found to be quite low. However, for traits with low genetic correlations, the joint reference data do not improve the prediction accuracy substantially for either population. [ABSTRACT FROM AUTHOR]

Background: Survival from birth to slaughter is an important economic trait in commercial pig productions. Increasing survival can improve both economic efficiency and animal welfare. The aim of this study is to explore the impact of genotyping strategies and statistical models on the accuracy of genomic prediction for survival in pigs during the total growing period from birth to slaughter. Results: We simulated pig populations with different direct and maternal heritabilities and used a linear mixed model, a logit model, and a probit model to predict genomic breeding values of pig survival based on data of individual survival records with binary outcomes (0, 1). The results show that in the case of only alive animals having genotype data, unbiased genomic predictions can be achieved when using variances estimated from pedigree-based model. Models using genomic information achieved up to 59.2% higher accuracy of estimated breeding value compared to pedigree-based model, dependent on genotyping scenarios. The scenario of genotyping all individuals, both dead and alive individuals, obtained the highest accuracy. When an equal number of individuals (80%) were genotyped, random sample of individuals with genotypes achieved higher accuracy than only alive individuals with genotypes. The linear model, logit model and probit model achieved similar accuracy. Conclusions: Our conclusion is that genomic prediction of pig survival is feasible in the situation that only alive pigs have genotypes, but genomic information of dead individuals can increase accuracy of genomic prediction by 2.06% to 6.04%. [ABSTRACT FROM AUTHOR]

The stability prediction is an effective approach to suppress the unstable milling process caused by the regenerative chatter. Through updating a numerical solution scheme (NSS), a fast prediction method is proposed in this paper. Firstly, a NSS is constructed by combining the Lagrange polynomial and Euler's method. Then, the solution of the differential equations described the milling process is transformed into the initial-value problem of the equation which is expressed by the built NSS over each small discrete time interval. Subsequently, the state transition matrix over one tooth passing period is established to predict the stability lobe diagram (SLD) via the Floquet theory. Finally, the computational performances of the proposed method are verified by the single and two DOF dynamic models. Compared with the complete discretization scheme, the computational accuracy and efficiency of the proposed method are increased by 2.69 times and 2.01 times, respectively. The proposed method reduces the computational accuracy by 2.16 times in comparison to the first-order full-discretization method, but it increases the computational efficiency by 2.2 times. [ABSTRACT FROM AUTHOR]

Integrating the single‐nucleotide polymorphisms (SNPs) significantly affecting target traits from imputed whole‐genome sequencing (iWGS) data into the genomic prediction (GP) model is an economic, efficient, and feasible strategy to improve prediction accuracy. The objective was to dissect the genetic architecture of intramuscular fat content (IFC) by genome wide association studies (GWAS) and to investigate the accuracy of GP based on pedigree‐based BLUP (PBLUP) model, genomic best linear unbiased prediction (GBLUP) models and Bayesian mixture (BayesMix) models under different strategies. A total of 482 Suhuai pigs were genotyped using an 80 K SNP chip. Furthermore, 30 key samples were selected for resequencing and were used as a reference panel to impute the 80 K chip data to the WGS dataset. The 80 K data and iWGS data were used to perform GWAS and test GP accuracies under different scenarios. GWAS results revealed that there were four major regions affecting IFC. Two important functional candidate genes were found in the two most significant regions, including protein kinase C epsilon (PRKCE) and myosin light chain 2 (MYL2). The results of the predictions showed that the PBLUP model had the lowest reliability (0.096 ± 0.032). The reliability (0.229 ± 0.035) was improved by replacing pedigree information with 80 K chip data. Compared with using 80 K SNPs alone, pruning iWGS SNPs with the R‐squared cutoff of linkage disequilibrium (0.55) led to a slight improvement (0.006), adding significant iWGS SNPs led to an improvement of reliability by 0.050 when using a one‐component GBLUP, a further increase of 0.033 when using a two‐component GBLUP model. For BayesMix models, compared with using 80 K SNPs alone, adding additional significant iWGS SNPs into one‐ or two‐component BayesMix models led to improvements of reliabilities for IFC by 0.040 and 0.089, respectively. Our results may facilitate further identification of causal genes for IFC and may be beneficial for the improvement of IFC in pig breeding programs. [ABSTRACT FROM AUTHOR]

Corrosion resistance of machined surface and its correlation with surface roughness have been the important concerns for sustainability of the final products. However, the pitting corrosion of laser-cladded Fe–Cr–Ni layers by turning exhibits susceptibility to surface roughness characteristics. In present study, the generation mechanism of pitting susceptibility by turning and the effect of burnishing on decreasing the pitting susceptibility were explored. To this end, a theoretical model of the potential difference between roughness peaks and valleys was established with considering the functional parameters of the surface roughness. Then, the correlations between the potential difference and pitting characteristics including pitting depth, width and area were analyzed in order to reveal the generation mechanism of pitting susceptibility. The occurrence of pitting corrosion could be predicted by the local potential difference, which was higher at the location where pitting corrosion would occur while lower where pitting corrosion did not occur. Finally, the influence of each functional parameter of surface roughness on the potential difference was analyzed using the proposed model, with which the machining schematics were discussed. On the basis of this research, it was expected to improve the corrosion resistance of the claddings by turning and subsequent burnishing process chain. [ABSTRACT FROM AUTHOR]

The purpose of this work is to investigate the effect of the WC content on the surface characteristics and nanoindentation behaviors of WC/Ni-based composite laser-clad coatings. Four NiCrSiBC coatings with WC wt% of 30%, 40%, 50%, and 60%, respectively, were clad on carbon steel substrates using a laser. The morphologies and phase compositions of four clad coatings were comparatively observed. In addition, the hardness and elastic modulus values of the four coatings were measured and quantitatively calculated. As a result, with the increase in WC, the coating grains were more refined. Meanwhile, cracks and WC particle breakage occurred in the 50–60% WC coatings, whereas this was not found in the 30–40% WC coatings. When the WC content increased from 40% up to 50%, the coating hardness and elastic modulus significantly increased. However, a further increase in WC from 50% to 60% did not result in considerable improvement in coating quality but considerably worsened the coating's cracking behavior instead. Therefore, for WC/Ni-based composite coatings, a threshold exists for the WC content, and this value was 50% within the experimental scope of this study. [ABSTRACT FROM AUTHOR]

The preparation of functional coatings on metal substrates is an effective method to enhance the surface of steel structures with good serviceability in applications for engineering parts. The objective of this research is to analyze the surface properties of two sorts of medium-entropy alloy (MEA) coatings prepared by laser cladding. After cladding, the two prepared coatings were strengthened by ultrasonic burnishing (UB) treatment. Cladding coating samples before and after being UB-treated were comparatively tested in order to investigate the process effects of UB. When compared with corresponding untreated coating samples, the roughness values of the two sorts of UB-treated samples were decreased by 88.7% and 87.6%, the porosities were decreased by 63.8% and 73.4%, and the micro-hardness values were increased by 41.7% and 32.7%, respectively. Furthermore, the two sorts of UB-treated coating samples exhibited better mechanical properties and wear resistance than corresponding untreated samples. [ABSTRACT FROM AUTHOR]

High mortality and involuntary culling rates cause great economic losses to the worldwide dairy cattle industry. However, there is low emphasis on wellness traits in replacement animals (dairy calves and replacement heifers) during their development stages in modern dairy cattle breeding programs. Therefore, the main objectives of this study were to estimate genetic parameters of wellness traits in replacement cattle (replacement wellness traits) and obtain their genetic correlations with 12 cow health and longevity traits in the Chinese Holstein population. Seven replacement wellness traits were analyzed, including birth weight, survival from 3 to 60 d (Sur1), survival from 61 to 365 d (Sur2), survival from 366 d to the first calving (Sur3), calf diarrhea, calf pneumonia, and calf serum total protein (STP). Single and bivariate animal models were employed to estimate (co)variance components using the data from 189,980 Holstein cattle. The genetic correlations between replacement wellness traits and cow longevity, health traits were calculated by employing bivariate models, including 6 longevity traits and 6 health traits (clinical mastitis, metritis, ketosis, displaced abomasum, milk fever, and hoof health or hoof disease). The estimated heritabilities (± SE) were 0.335 (± 0.008), 0.088 (± 0.005), 0.166 (± 0.006), 0.102 (±0.006), 0.048 (± 0.003), 0.063 (± 0.004), and 0.170 (± 0.019) for birth weight, Sur1, Sur2, Sur3, pneumonia, diarrhea, and STP, respectively. The majority of the genetic correlations among the 7 replacement wellness traits were negligible. The genetic correlations among Sur1, Sur2, and Sur3 ranged from 0.112 (Sur1 and Sur3) to 0.445 (Sur1 and Sur2) when fitting a linear model (estimates in the observed scale), and from 0.560 (Sur1 and Sur3) to 0.773 (Sur1 and Sur2) when fitting a threshold model (estimates in the liability scale). The genetic correlations between replacement wellness and cow longevity were low (absolute value lower than 0.30), but some of them were significantly different from zero. Compared with other replacement wellness traits, Sur3 and STP had relatively high genetic correlations with cow longevity. Replacement wellness traits are heritable and can be improved through direct genetic and genomic selection. The results from the current study will contribute for better balancing dairy cattle breeding goals to genetically improve dairy cattle wellness in the period from birth to first calving. [ABSTRACT FROM AUTHOR]

This paper investigates the brittle removal mechanism of ductile materials in ultra-high speed machining (UHSM). Firstly, a predictive model of critical cutting speed for UHSM is proposed with the theory of stress wave propagation. The predicted critical cutting speed for ductile-to-brittle transition of ductile materials is then validated by machining experiments of 7050-T7451 aluminum alloy at the cutting speeds ranging from 50 m/min to 8000 m/min. The experimental results show that fragmented chips are produced above the critical cutting speed of 5000 m/min for 7050-T7451 aluminum alloy. The scanning electron microscopic (SEM) images of chips, chip roots and finished workpiece surfaces are observed and analyzed. Large amounts of brittle cracks and cleavage steps are observed on the fragmented chip surface obtained under the ultra-high cutting speed. Due to the remained brittle cracks, the finished surface quality obtained with UHSM is worse than that obtained with high speed machining. Secondly, the specific energy models for the chip formation are proposed and validated by experiments under ductile regime machining and brittle regime machining, respectively. The specific energies consumed for continuous and serrated chip formation mainly include plastic deformation energy located in the primary shear zone, the friction work between the tool–chip interface, and the chip kinetic energy. The plastic deformation energy accounts for the largest proportion among the total specific energy. Comparatively, the specific energy consumed during fragmented chip formation mainly includes the local kinetic energy of fragments and fracture surface energy. When the chip morphology evolves from serrated to fragmented one, the specific energy consumed reduces substantially, which demonstrates that the UHSM is beneficial for the energy saving. Lastly, taking both of the material removal efficiency and machined surface quality into consideration, the UHSM is recommended to be applied in rough machining or semi-finishing, while high speed machining is recommended to be applied in finishing process. This research firstly reveals the control mechanism for ductile-to-brittle transition of ductile materials under critical cutting speed (i.e. critical strain rate) considering solid mechanics and metal cutting principles as well as energy consumption simultaneously. This paper is enticing from both engineering and analytical perspectives aimed at revealing the mechanism of UHSM and instructing the optimization of machining parameters. [ABSTRACT FROM AUTHOR]

High entropy alloys (HEAs) have become an ideal material for preparing cermets because of their properties, such as high hardness, good wear resistance, and excellent heat resistance. In this paper, TiC-Fe/HEA cermet was prepared by vacuum sintering with Fe powder, HEA(FeCoCrNiMn) powder, and TiC particles. The effect of HEA content on the microstructure and properties of TiC-Fe cermet was studied, and the preparation process of cermet was optimized. The results show that the cermet grains without HEA are angular or polygonal, while the cermet grains with HEA are round and oval. With the addition of HEA, the grain size decreased at first and then increased. In addition, with increasing HEA content, the hardness, transverse rupture strength, and fracture toughness of cermet first increased and then decreased, while the relative density decreased slightly. HEA had the best properties among these HEA cermets at 10 wt%, and its hardness, transverse rupture strength (TRS), and fracture toughness (K IC) reached 1530 HV 30 , 980 MPa, and 10.57 MPa•m1/2 respectively. Compared with cermet without HEA, these values were increased by 36%, 20%, and 11%, respectively. • A new type of TiC-Fe/FeCoCrNiMn cermet is prepared by optimizing the material ratio and preparation process. • The properties and formation mechanism of core-rim structure are revealed. • Hardness, TRS and K IC of cermet with 10%HEA are 1530HV 30 , 980 MPa and 10.57MPa•m1/2. [ABSTRACT FROM AUTHOR]

The purpose of this work is to investigate the cracking behavior and crack formation mechanism of high WC wt% composite coatings. Three NiCrSiBC-WC composite coatings with respective WC wt% of 40%, 50%, 60% were prepared on carbon steel substrates by laser. The macro- and micro-morphologies together with phase compositions of three coatings were comparatively observed. Further, the hardness, residual stress and toughness values of three coatings were tested and calculated quantitatively to get a clear understanding of crack formation. As a result, cracks occurred in 50% and 60%WC coatings but not being found in 40%WC coating. With increasing WC wt%, grains were more refined while more cracks occurred. The cracking of 50%WC coating was attributed to high tensile residual stress coupled with low toughness. Whereas compared with 50%WC coating, the higher crack susceptibility of 60%WC coating was mainly because of further increased residual stress. [ABSTRACT FROM AUTHOR]

DLC has been applied as coating material in the machining of difficult-to-cut materials, and shows a good cutting performance. In this study, Cr/W-DLC/DLC-coated tools were compared with other three kinds of coated tools (TiC-, TiAlN-, Al2O3-) to investigate the cutting performance in the machining of Al–Si alloy. The influence of Cr/W-DLC/DLC-coated tools on the cutting performance under different cutting speeds was studied. Cutting force, cutting temperature, heat partition coefficient, cutting deformation rate, plastic deformation of machined surface, the interface temperature, and stress were investigated numerically with the aid of finite element method (FEM). Actual cutting experiments were carried out to verify the FEM models by means of the cutting force and cutting temperature measurement. The investigation results show that Cr/W-DLC/DLC-coated tool had the best cutting performance among these four kinds of coated tools. With the increasing of cutting speeds, cutting force and cutting temperature showed an increase trend, while the plastic deformation depth of machined surface and heat partition into cutting tool all showed a decrease trend during the machining with Cr/W-DLC/DLC-coated tool. This investigation can provide the theory basis or technical guidance for the cutting practice with Cr/W-DLC/DLC-coated tools. [ABSTRACT FROM AUTHOR]

Acute myocardial infarction (AMI) is the main cause of death from cardiovascular diseases. Thus, early diagnosis of AMI is essential for the treatment of irreversible damage from myocardial infarction. Traditional electrocardiograms (ECG) cannot meet the specific detection of AMI. Cardiac troponin I (cTnI) is the main biomarker for the diagnosis of myocardial infarction, and the detection of cTnI content has become particularly important. In this review, we introduced and compared the advantages and disadvantages of various cTnI detection methods. We focused on the analysis and comparison of the main indicators and limitations of various cTnI biosensors, including the detection range, detection limit, specificity, repeatability, and stability. In particular, we pay more attention to the application and development of electrochemical biosensors in the diagnosis of cardiovascular diseases based on different biological components. The application of electrochemical microfluidic chips for cTnI was also briefly introduced in this review. Finally, this review also briefly discusses the unresolved challenges of electrochemical detection and the expectations for improvement in the detection of cTnI biosensing in the future. [ABSTRACT FROM AUTHOR]

Despite the importance of the quality of semen used in artificial insemination to the reproductive success of dairy herds, few studies have estimated the extent of genetic variability in semen quality traits. Even fewer studies have quantified the correlation between semen quality traits and male fertility. In this study, records of 100,058 ejaculates collected from 2,885 Nordic Holstein bulls were used to estimate genetic parameters for semen quality traits, including pre- and postcryopreservation semen concentration, sperm motility and viability, ejaculate volume, and number of doses per ejaculate. Additionally, summary data on nonreturn rate (NRR) obtained from insemination of some of the bulls (n = 2,142) to cows in different parities (heifers and parities 1–3 or more) were used to estimate correlations between the semen quality traits and service sire NRR. In the study, low to moderate heritability (0.06–0.45) was estimated for semen quality traits, indicating the possibility of improving these traits through selective breeding. The study also showed moderate to high genetic and phenotypic correlations between service sire NRR and some of the semen quality traits, including sperm viability pre- and postcryopreservation, motility postcryopreservation, and sperm concentration precryopreservation, indicating the predictive values of these traits for service sire NRR. The positive moderate to high genetic correlations between semen quality and service sire NRR traits also indicated that selection for semen quality traits might be favorable for improving service sire NRR. [ABSTRACT FROM AUTHOR]

The coating effect on the cutting temperature has long been a hot topic in understanding heat transfer mechanism in machining coated tools, and especially the multi-layer coated tools. For multi-layer coated tools, the coating structure, coating thickness, and coating material will affect the cutting temperature of the tools. This paper is devoted to the cutting temperature in dry turning of H13 hardened steel with multi-layer coatings. New analytical models for estimating coating temperature and coating–substrate interface temperature were proposed. The multi-layer coating can be equivalent to mono-layer composite coating, which applies equivalent coating layer approach, and was developed to estimate the cutting temperature in turning by heat transfer model of mono-layer coated tool. The analyzed results were compared with appropriate experimental process data using thermocouples and FEM simulated data. The models can accurately reflect the cutting temperature of two multi-layer coated tools under the same cutting condition. [ABSTRACT FROM AUTHOR]