The strip shape inheritance model is widely applied to improve the strip shape quality in tandem cold rolling (TCR). However, the inheritance mechanism is still currently unclear. To bridge this gap, ...this paper presents a new numerical method for calculating the strip crown inheritance factor. In addition, the effects of the entry strip crown on exit strip crown and flatness were quantitatively analysed at each stand in the TCR using a novel three-dimensional (3D) multi-stand elastic–plastic finite element (FE) model. The results show that the strip crown inheritance factor increases slowly from S1 (stand 1) to S3 (stand 3), while rising sharply from S3 to S5 (stand 5), reaching a peak value of 0.495 μm/μm at S5. This trend coincides with that of strip plastic rigidity, which verifies that the strip crown inheritance factor is dependent on the strip plastic rigidity. Furthermore, the variation of strip crown and flatness under different entry strip crowns from S1 to S5 is jointly influenced by the pass reduction and strip plastic rigidity. Moreover, the strip crown inheritance factor increases with the deformation resistance of the strip at both S1 and S5. These findings not only offer a fresh perspective to understand the mechanism of strip crown inheritance, but also provide an important basis for optimising the strip shape control in the TCR process.
In this paper, the effect of strip spacing on the aerodynamic performance of a high-speed pantograph with a double-strip is numerically studied using a shear stress transport turbulence model. Seven ...different strip spacings varied from 100 to 700 mm are considered. The errors in pantograph resistance between numerical simulation and wind tunnel test are within 5% in both knuckle-downstream and knuckle-upstream operating conditions. The drag and lift forces of the strip increase with the strip spacing when the train's running speed is 350 km/h. By considering the two strips individually, it is interesting to find that the lift force on the first strip tends to be stable as the spacing reaches up to 600 mm in both operating conditions, whereas the lift force on the second strip increases continuously with the spacing in the whole range of 100-700 mm. Furthermore, the aerodynamic coefficient of the strip is a nearly constant value at different running speeds, which increases with the strip spacing, suggesting that the relationship between the aerodynamic forces and the spacing of strips obtained in the current study can be extended to any speed level in the range of 200-350 km/h.
Feeding a cold steel strip into continuous casting (CC) mold is an effective method to improve the quality of large round bloom. However, it is difficult to assess the correlation between the bloom ...quality and the initial temperature of the strip. Therefore, a three‐phase mixed columnar–equiaxed solidification model is developed to evaluate the effect of feeding strip temperature on macrosegregation and solidification structure in a large vertical CC round bloom. The results show that feeding the steel strip induces “crystal rain” in the liquid core of the bloom and increases the volume fraction of the equiaxed phase. After feeding a strip, the flow direction of molten steel is changed, and the flow velocity is increased in the liquid core of the bloom. Furthermore, with initial temperature of the strip decreases, the production efficiency is improved. Compared to the four conditions investigated, the carbon distribution in the bloom is the most uniform, the negative segregation at the centerline of the bloom is the weakest with the value of −35.50%, and the extreme value difference of the macrosegregation index at 20 m below the meniscus is the smallest with the value of 38.35% under the condition of
T
initial
= 500 K.
To comprehensively understand the effect of oscillation on cooling capacity of steel strip, a mathematical model is proposed to investigate the distribution of temperature fields in continuous cast ...slabs, taking into account the oscillatory feeding process. Strip oscillation results in a periodic variation of nearby molten steel flow. It intensifies the turbulence of surrounding molten steel and enhances the interfacial heat transfer. During the feeding process, the morphology of strip undergoes three stages: upheaval, fluctuation, and disappearance. As the strip oscillation frequency increases, the maximum cross‐sectional area of the strip gradually decreases during the upheaval stage, the fluctuation stage gradually disappears, and the strip disappearance speed gradually increases during the disappearance stage. These observations suggest that an increase in the oscillation frequency accelerates the melting of the strip, which is caused by the enhanced heat transfer between the strip and molten steel. This results in a gradual growth of strip's cooling capacity and a decrement in the liquid fraction of molten steel surrounding the strip. In addition, feeding strip is advantageous in preventing the jet from impinging onto narrow surfaces of slab. The blocking effect initially increases and then remains almost unchanged as the strip oscillation frequency increases.
The cooling capacity of strip gradually increases with an increment in the oscillation frequency. As feeding strip oscillation frequency increases, the area of the low‐liquid‐fraction region gradually increases, which is beneficial in promoting central nucleation and grain growth during the actual production process.
Deoxynivalenol (DON) and zearalenone (ZEN) are mycotoxins that contaminate a wide range of grains and crops. In this study, a one-step time-resolved single-channel immunochromatographic test strip ...based on europium ion polystyrene fluorescence microspheres was first developed for sensitive and quantitative detection of DON and ZEN. The concentration of the artificial antigen and the mass ratio of the monoclonal antibody to fluorescent microspheres for conjugation were optimized to simplify the sample addition process during immunochromatographic assay and improve the on-site detection efficiency. The limits of detection (LOD) of the single-channel immunochromatographic test strip for DON and ZEN detection were 0.17 and 0.54 μg/L, respectively. Meanwhile, the dual-channel immunochromatographic test strip was designed to simultaneously detect DON and ZEN, with LODs of 0.24 and 0.69 μg/L achieved for DON and ZEN, respectively. The developed test strips also yielded recovery results consistent with that obtained by LC-MS/MS for DON and ZEN detection in real samples of wheat and corn flour, confirming the practicability and reliability of the test strip. The developed immunochromatographic test strips realize quick and sensitive detection of DON and ZEN, exhibiting potential for broad applications in the point-of-care testing platform of multiple mycotoxins in agricultural products.
Graphic abstract
•The defect detection samples of steel strip are complex and changeable.•Anchor-Free is used to detect targets with large scale difference.•The Dense structure provides a significant improvement in ...high resolution data.
During steel strip production, mechanical forces and environmental factors cause surface defects of the steel strip. Therefore, detection of such defects is key to the production of high quality products. Moreover, surface defects of the steel strip cause great economic losses to the high-tech industry. So far, few studies have explored methods of identifying the defects, and most of the currently available algorithms are not sufficiently effective. Therefore, we developed an end-to-end defect detection model based on YOLO-V3. Briefly, the anchor-free feature selection mechanism was utilized to select an ideal feature scale for model training, replace the anchor-based structure, and shorten the computing time. Next, specially designed dense convolution blocks were introduced into the model to extract rich feature information, which effectively improves feature reuse, feature propagation, and enhances the characterization ability of the network. The experimental results show that, compared with other comparison models, the improved model proposed in this study has higher performance. For instance, the proposed model yielded 71.3% mAP on the GC10-DET dataset, and 72.2% mAP on the NEU-DET dataset.
The industrial process monitoring and operating performance assessment techniques are of great significance to ensure the safety and efficiency of the production and to improve the comprehensive ...economic benefits for the modern enterprises. In this paper, a new key performance indicator (KPI) oriented nonlinear process monitoring and operating performance assessment method is proposed based on the improved Hessian locally linear embedding (HLLE), in view of the problems of strong nonlinearity, high dimension and information redundancy in actual industrial process data. Firstly, in order to characterise the similarities of samples in both temporal and spatial dimensions, a new measurement, based on Finite Markov theory, is defined to replace the Euclidean distance in traditional HLLE. Secondly, by mining the relationships between process variables and the key performance indicator, the KPI oriented feature extraction method is developed. On this basis, the monitoring statistics is constructed and the corresponding control limit is determined for the real-time fault detection. After that, a new operating performance assessment approach based on sliding window Kullback-Leibler divergence is put forward to facilitate maintenance or adjustments. Finally, the proposed method is applied to the hot strip mill process, and the results show the effectiveness.
In this paper, a novel wideband substrate integrated suspended parallel strip line (SISPSL) to differential shielded grounded coplanar waveguide (GCPW) transition is proposed. By embedding the ...traditional double‐side parallel‐strip line inside multilayer boards, SISPSL has the advantage of self‐packaging and there is almost no radiation loss. SISPSL has inherent differential transmission properties, and a transition from SISPSL to differential GCPW is designed based on multilayer boards. The measured bandwidth of the back‐to‐back transition is from 0.01 to 40 GHz.
Introduction: Global detection of bacteria harboring metallo-β-lactamase (MBL) genes has increased at an alarming rate. However, there is no
concurrent increase in available antibiotics for ...treatment, which has turned these infections into a public health emergency. Newer antibiotics,
such as ceftazidime/avibactam in combination with aztreonam and cefiderocol, constitute alternative options available for clinical use. While
aztreonam remains stable against MBL-producing Enterobacterales, there is often concurrent production of other enzymes, such as extendedspectrum
β-lactamases, AmpC β-lactamases, and serine carbapenemases, which can result in aztreonam resistance. The combination of ceftazidime/
avibactam and aztreonam is an appealing alternative, as avibactam can deactivate other β-lactamases, thereby activating aztreonam.
Materials and Methods: The synergistic activity between ceftazidime/avibactam and aztreonam in aztreonam-resistant strains was investigated
using the strip stacking method previously described. The findings are presented as numbers and percentages.
Results: Out of the 50 isolates, 43 (86%) demonstrated resistance to aztreonam, five (10%) were classified as intermediate, and two (4%) were
sensitive to aztreonam. Aztreonam and ceftazidime/avibactam demonstrated a synergistic effect in all 43 (100%) isolates resistant to aztreonam.
Synergistic action between aztreonam and ceftazidime/avibactam restores the activity of aztreonam against MBL. Avibactam, a novel β-lactam
inhibitor, extends potent activity against class A β-lactamases and AmpC determinants.
Conclusion: This study demonstrated 100% synergistic activity between aztreonam and ceftazidime/avibactam among MBL-producing
Enterobacterales.
A novel triboelectric nanogenerator (TENG) is designed, based on flexible and transparent vertical‐strip arrays, for environmental wind‐energy harvesting. Given the low cost, simple structure, and ...wide applicability, the TENGs present a green alternative to traditional methods used for large‐scale wind‐energy harvesting.
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