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.
•Helical strip inserts promote flow turbulence without flow separation and generate swirl.•Overall heat transfer performance of insert fitted annuli is higher than that of plain annuli.•Figure of ...Merit of the insert is better at lower Reynolds number.•Flow physics parameters such as velocity, temperature, pressure, eddy viscosity, and turbulent kinetic energy are inter-related.
Helical baffles, wire coils, and rectangular ribs are used to improve the annular fluid flow turbulence and heat transfer performance. Among the different insert types, loose-fitted helical baffles or strips are of major interest because of their better performance. Tight-fitted helical strips can show better performance in the annular flow because they can act as a fin besides acting as a swirl generator compared to loose-fitted ones. For that reason, a three-dimensional (3D) computational fluid dynamics (CFD) study is performed to investigate the heat transfer and pressure drop characteristics of turbulent flow (4000 ≤ Re ≤ 10000) at annuli with and without tight-fitted helical strip inserts. Annuli with 0.6, 0.7, and 0.8 annuli diameter ratio (ADR) are studied for plain and helical strip inserts with pitch ratios (PRs) of 1, 2, and 3. Result showed that higher heat transfer coefficient (HTC) and friction factor were found for insert-fitted annuli compared to those of plain annuli. HTC increased with increase in Re and ADR and decrease in insert PR. The best performance was for 0.8-ADR insert-fitted annuli: 171%–207% (1 PR), 82%–105% (2 PR), and 56%–75% (3 PR) compared to 0.8-ADR plain annuli. Although HTC increased with increase in ADR, the Nusselt number (Nu) decreased because of the smaller hydraulic diameter. Nu increased with increase in Re but decreased with higher ADR and insert PR. The friction factor increased with decrease in insert PR and ADR and decreased with increase in Re. A figure of merit (FoM) was used to combine the benefit of heat transfer enhancement and the drawback of higher pressure drop. The FoM ranged from 0.9 to 1.3, 0.94 to 1.22, and 0.92 to 1.24 for ADR values of 0.6, 0.7, and 0.8, respectively, for a specific Re range. The heat transfer performance obtained was in the order of 3 PR < 2 PR < 1 PR for insert-fitted annuli, but the FoM followed 1 PR < 2 PR < 3 PR because of a much higher pressure drop for lower PR. This study confirms that inserts improve heat transfer, which is better at lower Re.
Abstract
The coiling stable roll of hot-dip galvanized is a defect formed in the galvanizing process. The zinc slags and floating foreign matters in the zinc pot will directly or indirectly adhere to ...the roll surface of the stabilizer roll with the flow of zinc liquid. When the strip steel contacts the stabilizer roll, the zinc slag will extrude and deform the iron base plate and form pits. In this paper. The causes of the defects were analyzed. There were two methods to eliminate the coiling stable roll, that is, to reduce the generation and accumulation of zinc slags in the zinc pot. The main measures are first to control the temperature of the strip entering the zinc can plate and the temperature of the molten zinc, and then control the amount of residual bottom residue before the zinc pot goes online. Another is to ensure the cleanliness of the steel strip before it enters the molten zinc. Based on this, the main measures implemented are: improving the cleaning ability of the cleaning section and improving the reducing ability during annealing to inhibit the formation and accumulation of zinc powder in the furnace head area.
•A novel thermohydraulic characteristics analysis has been carried out.•Double strip compared with single strip helical screw tape in heat exchanger tube.•CuO/water nanofluid used as a working fluid ...and compared with water.•Nusselt number and Thermal performance factor are higher with CuO in double strip.•Correlations for Nusselt number and friction factor developed.•Double strip helical screw tape inserts are suitable to reduce heat exchanger size.
This paper presents the experimental analysis to evaluate thermo-hydraulic characteristics of single and double strip helical screw tape inserts in the copper tube with water and CuO/water nanofluid at constant heat flux conditions at twist ratio of 1.5, 2.5 and 3. Results show that Nusselt number and friction factor with double strip helical screw tape inserts achieves substantial enhancement as compared to single strip helical screw tape insert. The Nusselts number with nano-fluid increases and achieves the increment by 182% and 170% for double strip and single strip helical screw tape inserts respectively, at a twist ratio of 1.5. Whereas at twist ratio of 2.5 and 3, thermal performance factor shows excellent performance for double strip helical screw tape inserts, that makes it suitable for heat exchanger to reduce the size of it for thermal applications. Correlations for Nusselt number and friction factor are also developed within the range of Reynolds number, twist ratio and Number of strips.
0.3 mm‐thick grain‐oriented silicon steel sheets with varying Y contents are produced via twin‐roll strip‐casting and two‐stage cold rolling process. This study primarily investigates the evolution ...of microstructure, texture, and precipitation along the processing. Specifically, the effect of rare earth Y on second‐phase particle precipitation in ultralow carbon grain‐oriented silicon steel is examined. Results indicate that higher Y content will consume beneficial inhibitor elements such as S and N, leading to the formation of coarse rare earth inclusions (≈10 μm) in the cast strip. This significantly diminishes inhibition ability and magnetic induction (B8 = 1.58 T≈1.71 T). On the contrary, the addition of trace Y can accelerate the precipitation of inhibitors. During the intermediate annealing stage, steel with trace Y exhibits a significant enhancement in precipitate distribution density (from 2.8 μm−2 to 13.6 μm−2), and the final magnetic induction B8 increases from 1.86 T to 1.91 T compared to steel without Y. In addition, the results of first‐principle calculations based on density functional theory reveal that the doped Y atom prefers to segregate at the Al–N interface, and the interface energy reduces from 1.871 J m−2 to 1.024 J m−2, thereby promoting the precipitation of AlN.
The addition of trace rare earth Y to the strip‐cast grain‐oriented silicon steel can promote the rapid precipitation of AlN inhibitors. The doped Y atoms tend to segregate at the Al–N interface and reduce the precipitated interface energy.
To comprehensively comprehend variation of strip shape (strip feeding depth and maximum steel sheath cross‐sectional area) under different process parameters (strip feeding speed, strip oscillation ...frequency, strip amplitude, molten steel superheat, strip width, and strip thickness), a mathematical model of feeding strip process has been developed herein. Flow near steel strip is analyzed. Meanwhile, the qualitative relationship between strip shape and process parameters is derived based on energy conservation within the system of molten steel and steel strip. The results show that strip feeding depth is positively correlated with strip feeding speed, strip width, and strip thickness, while it's negatively correlated with strip oscillation frequency, strip amplitude, and molten steel superheat; maximum steel sheath cross‐sectional area is positively correlated with strip width and strip thickness, while it's negatively correlated with strip feeding speed, strip oscillation frequency, strip amplitude, and molten steel superheat. Based on the calculated results, the quantitative relationships are proposed to predict the strip feeding depth and maximum steel sheath cross‐sectional area with aforementioned process parameters, which are suitable for the situations that the strip tip is located between the outlet of submerged entry nozzle and the end of the liquid core.
Herein, a mathematical model has been developed to obtain the strip feeding depth and maximum steel sheath cross‐sectional area under different process parameters including strip feeding speed, strip oscillation frequency, strip amplitude, molten steel superheat, strip width, and strip thickness. This study reveals the comprehensive influence of various process parameters on the shape of steel strip
•Deep learning is applied to segment the hot-rolled steep strip surface defects.•A DSUNet, which can precisely and efficiently segment defects, is proposed.•The results indicate that the DSUNet can ...achieve state-of-the-art performance.
Accurate and efficient image segmentation can contribute to improving the recognition rate of surface defects for hot-rolled steel strips. However, due to its variances in shape, position, defect type and fuzzy boundary, surface defect segmentation is a challenging task. To address this issue, a depth-wise separable U-shape network (DSUNet) is proposed. In order to reduce the computation complexity and accelerate the segmentation performance, depth-wise separable convolution is employed to replace the traditional convolutional layer. In addition, a multi-scale module is proposed to extract multi-scale context and improve the segmentation accuracy. The experimental results indicate that the accuracy and dice of DSUNet reach 95.42% and 80.8%, respectively, and the DSUNet can segment 38.5 images per second, which suggests that the DSUNet can precisely segment surface defects for hot-rolled steel strip with high efficiency.
