Abstract
American mink (Neovison vison) is the major source of fur for the fur industries worldwide and Aleutian disease (AD) is causing severe financial losses to the mink industry. Different ...methods have been used to diagnose the AD in mink, but the combination of several methods can be the most appropriate approach for the selection of AD resilient mink. Iodine agglutination test (IAT) and counterimmunoelectrophoresis (CIEP) methods are commonly employed in test-and-remove strategy; meanwhile, enzyme-linked immunosorbent assay (ELISA) and packed-cell volume (PCV) methods are complementary. However, using multiple methods are expensive; and therefore, hindering the corrected use of AD tests in selection. This research presented the assessments of the AD classification based on machine learning algorithms. The Aleutian disease was tested on 1,830 individuals using these tests in an AD positive mink farm (Canadian Centre for Fur Animal Research, NS, Canada). The accuracy of classification for CIEP was evaluated based on the sex information, and IAT, ELISA and PCV test results implemented in seven machine learning classification algorithms (Random Forest, Artificial Neural Networks, C50Tree, Naive Bayes, Generalized Linear Models, Boost, and Linear Discriminant Analysis) using the Caret package in R. The accuracy of prediction varied among the methods. Overall, the Random Forest was the best-performing algorithm for the current dataset with an accuracy of 0.89 in the training data and 0.94 in the testing data. Our work demonstrated the utility and relative ease of using machine learning algorithms to assess the CIEP information, and consequently reducing the cost of AD tests. However, further works require the inclusion of production and reproduction information in the models and extension of phenotypic collection to increase the accuracy of current methods.
Electrochemical discharge machining (ECDM) combines the process characteristics of both electric discharge machining (EDM) and electrochemical machining (ECM). ECDM combines the advantages of both ...processes to achieve high precision and high surface-quality machining. It has a broad application prospect. This paper briefly introduces the development history of ECDM. The machining mechanism of ECDM is explained. The applications of ECDM machining features are listed, including drilling, milling, turning, cutting, and hybrid machining methods, for process performance enhancement. A comprehensive analysis of the process parameters of ECDM and their impact on process performance is presented. The paper surveys the extensive ECDM research and concludes with a discussion of the future direction of ECDM.
Graphical Abstract
This research discusses the effect of typical characteristic dimensions of electrodes on electric arc electrochemical composite machining (EAECM). The flow rate and debris removal capability of ...electrodes with different characteristic dimensions were investigated by flow field simulation. Single-factor machining experiments were conducted. The discharge characteristics, process indicators and machined surfaces of electrodes were analyzed it was found that the tubular electrode has a demarcation phenomenon that affects the surface quality. The results indicate that the use of electrodes with large inner diameters is favorable to improve the surface consistency. The use of electrodes with small outer diameters improves the overall surface quality but increases the electrode wear. Finally, the fracture mechanism of thin-walled electrodes was revealed by stress field simulations and experiments. In conclusion, in order to improve the machining effect of EAECM, large-diameter (inner and outer diameter) electrodes with wall thickness greater than 2 mm should be selected.
Short electric arc milling (SEAM) is an electrical discharge machining method characterized by low voltage and high current. This method has high machining efficiency, and the eroded material is ...quickly discharged from the discharge gap by a high-speed rotating tool electrode and a certain pressure of the gas-liquid mixed medium. In this paper, the effects of tool polarity, working medium, voltage, duty cycle, frequency, and flushing pressure on the performance of short electric arc milling were investigated by using the material removal rate (MRR), tool mass wear ratio (
θ
), and surface roughness (SR) as technical indicators. Moreover, the surface morphology, cross-section morphology, chemical composition, and micro-hardness of GH4169 after machining were also studied, and the machine mechanism was further revealed. This work lays a foundation for more efficient and high-precision short electric arc milling.
Aleutian disease (AD), caused by the Aleutian mink disease virus (AMDV), is a major health concern that results in global economic losses to the mink industry. The unsatisfactory outcome of the ...culling strategy, immunoprophylaxis, and medical treatment in controlling AD have urged mink farmers to select AD resilient mink based on several detection tests, including enzyme-linked immunosorbent assay (ELISA), counterimmunoelectrophoresis (CIEP), and iodine agglutination test (IAT). However, the genetic analysis of these AD tests and their correlations with pelt quality, reproductive performance, packed-cell volume (PCV), and harvest length (HL) have not been investigated. In this study, data on 5,824 mink were used to estimate the genetic and phenotypic parameters of four AD tests, including two systems of ELISA, CIEP, and IAT, and their genetic and phenotypic correlations with two pelt quality, five female reproductive performance, PCV, and HL traits. Significances (P < 0.05) of fixed effects (sex, year, dam age, and color type), covariates (age at harvest and blood sampling), and random effects (additive genetic, permanent environmental, and maternal effects) were determined under univariate models using ASReml 4.1 software. The genetic and phenotypic parameters for all traits were estimated under bivariate models using ASReml 4.1 software. Estimated heritabilities (±SE) were 0.39 ± 0.06, 0.61 ± 0.07, 0.11 ± 0.07, and 0.26 ± 0.05 for AMDV antigen-based ELISA (ELISA-G), AMDV capsid protein-based ELISA, CIEP, and IAT, respectively. The ELISA-G also showed a moderate repeatability (0.58 ± 0.04) and had significant negative genetic correlations (±SE) with reproductive performance traits (from −0.41 ± 0.16 to −0.49 ± 0.12), PCV (−0.53 ± 0.09), and HL (−0.45 ± 0.16). These results indicated that ELISA-G had the potential to be applied as an indicator trait for genetic selection of AD resilient mink in AD endemic ranches and therefore help mink farmers to reduce the adverse effects caused by AD.
A favorable flow field enhances the product transport capacity and also increases the electrochemical mass transfer rate. In this paper, an end-side connected electrode suitable for electric arc ...electrochemical composite milling was proposed based on the existing flushing form. The aim is to simultaneously enhance the machining of the groove surface and the side. The flushing form was optimized by the flow field, and it was shown that the internal flushing increased the area of the high flow rate zone of the bottom gap. In the experiments, it was found that the internal flushing reduced the secondary discharge probability, the accumulation of re-solidified material on the groove surface was decreased, and the surface dissolution was uniform with low oxidation. However, the central jet is lost along the course and a zero velocity zone exists at the corners of the groove. Therefore, the sidewall open flow field is proposed to reduce the sidewall recast layer. It was verified that the sidewall slots of the positive flow type improved both the surface quality of the groove surface and the side wall. It was also found that the increase in the number of open grooves facilitates the generation of uniform debris removal.
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•A gas-liquid-solid three-phase flow model was developed for flow field optimization.•The flushing form was optimized and the important role of internal flushing was demonstrated.•An end-side connected electrode with improved surface and sidewalls quality was proposed.•The optimized end-side connected electrode can be adapted to more complex working conditions.
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•Theoretical model of EAECM material removal mechanism was developed.•Experiments showed that the feed rate is the decisive factor regulating the percentage of EAM/ECM action in ...EAECM.•Waveform and surface integrity measurements showed that the structural evolution of the machined surface transitions from a black recast layer covered surface to a brightly finished material matrix.•Cross-sectional experimental results showed that EAECM can obtain good surface quality at low discharge energies and high electrolyte concentrations with no recast layer.
In this study, a theoretical model about the conversion mechanism of material removal by electric arc electrochemical machining (EAECM) was derived. The limiting conversion rate of ECM-EAECM was measured on this basis. The current waveform, surface integrity, shape accuracy and process indexes during machining were measured and evaluated. The results showed that when the limiting conversion rate of ECM was exceeded, the material removal consisted of alternating effects of electric arc machining (EAM) and ECM. The proportion of EAM increased and the surface structure evolved into discharge defects, verifying the correctness of the theory. In addition, parametric crossover experiments were performed to clarify the degree of parametric response to EAECM modulation. Finally, the optimal combination of parameters resulted in a material removal rate of up to 5452 mm3/min, a relative electrode wear rate of 1.39 %, and a surface roughness of only 4.62 μm.
By introducing a high concentration of electrolyte into the working medium of conventional short electric arc machining (SEAM), we have realized the removal of surface defects of SEAM using ...electrochemical machining (ECM) during the discharge of SEAM. This process is called short electric arc-electrochemical (SEAM-ECM) combined machining. The forms of power excitation mainly use pulsed and constant voltage DC. Therefore, this research first reveals the arc-breaking and action mechanism of SEAM-ECM combined machining under two excitation forms by single-pulse simulation and experiment. The results show that DC excited arc-breaking is an adaptive arc-breaking over the discharge gap; the intensity and duration of ECM action of DC excitation are higher than that of pulsed excitation; at the same current strength, the arc-breaking time of DC excitation is about three times more than that of pulsed excitation (duty cycle of 55%). In addition, continuous discharge experiments are conducted to verify the machining effect of SEAM-ECM combined machining. The results show that DC excitation tends to form a continuous arc during machining, aggravating copper electrode loss and reducing the workpiece’s dimensional accuracy and the material removal rate. The concentrated discharge energy also produces deeper discharge pits, making the workpiece surface rougher relative to the pulsed excitation. The machining differences between the two excitation methods at different voltages are compared, showing that a balance exists between SEAM and ECM under suitable machining conditions.
Soybean is usually grown under rain‐fed conditions, and long‐term drought stress often occurs with short‐term heat stress. This study aimed to investigate changes in the photosynthetic ...characteristics of subtending leaves and their relationships with pod development under short‐term heat, long‐term drought and their combined stresses. Short‐term heat stress lasted for 5 days began at R5 stage, and long‐term drought stress lasted from R5 stage until maturity, respectively. No significant effect was observed on pod development under short‐term heat stress alone due to unaffected net photosynthetic rate after treatment and PSII recovery after the heat stress release. Except that the reduction of sucrose content had been brought forward from 12 to 5 days after treatment under combined stresses, application of combined stresses caused similar responses to long‐term drought stress alone on the photosynthetic characteristics of subtending leaves and pod development, but more pronounced under combined stresses. Reduced pod weight and seed weight per pod under long‐term drought stress alone or combined stress due to a decrease in the net photosynthetic rate and production of sucrose and starch, especially after 19 days of treatment. Findings from this study demonstrate that under combined stress, long‐term drought stress had a dominant effect on the photosynthetic performance of subtending leaves and pod development over short‐term heat stress; moreover, even short‐term heat stress also exacerbates the negative effects of long‐term drought stress.
