Numerical Study of Random Corrosion Characteristics of Metal Based On the Cellular Automata Method

In the production process of coal chemical companies, the corrosion of metal equipment and the resulting shortening of its service life can cause safety hazards. Simulation modeling of pit emergence and development during corrosion evolution provides a new approach to corrosion research. By analyzing the effect of different parameters on causing corrosion to occur, it is possible to reflect the influence of complex physico-chemical systems. In this paper, the simulation of a meta-cellular automaton model of pit growth under diffusion and the introduction of a passivation probability to correct the chemical reaction rate are developed; The effect of reaction passivation probability, chemical reaction rate and diffusion coefficient on the degree of corrosion was also analyzed by means of quantitative analysis. The results show that for metal corrosion loss processes, the degree of corrosion damage decreases with increasing probability of reactive passivation and increases with increasing chemical reaction rate, increasing electrolyte concentration and increasing time step. The CA model was applied to simulate the growth and change of pitting corrosion of metal materials with their corrosion protection layer under damaged conditions. The corrosion model can simulate the corrosion morphology change characteristics similar to the real metal to the corrosion pit evolution simulation related research has certain scientific, validity, reference

Numerical Study of Random Corrosion Characteristics of Metal Based On the Cellular Automata Method

In the production process of coal chemical companies, the corrosion of metal equipment and the resulting shortening of its service life can cause safety hazards. Simulation modeling of pit emergence and development during corrosion evolution provides a new approach to corrosion research. By analyzing the effect of different parameters on causing corrosion to occur, it is possible to reflect the influence of complex physico-chemical systems. In this paper, the simulation of a meta-cellular automaton model of pit growth under diffusion and the introduction of a passivation probability to correct the chemical reaction rate are developed; The effect of reaction passivation probability, chemical reaction rate and diffusion coefficient on the degree of corrosion was also analyzed by means of quantitative analysis. The results show that for metal corrosion loss processes, the degree of corrosion damage decreases with increasing probability of reactive passivation and increases with increasing chemical reaction rate, increasing electrolyte concentration and increasing time step. The CA model was applied to simulate the growth and change of pitting corrosion of metal materials with their corrosion protection layer under damaged conditions. The corrosion model can simulate the corrosion morphology change characteristics similar to the real metal to the corrosion pit evolution simulation related research has certain scientific, validity, reference

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

Optimization of the Stacking Plans for Precast Concrete Slab Based on Assembly Sequence

Precast concrete (PC) slabs are widely used in the assembly of concrete residential buildings. The PC slabs are manufactured at the factory and then arranged in stacks for transport to the construction site for assembly. Currently, optimization of the stacking plans for PC slabs focuses on yard-space utilization and transportation efficiency and rarely considers the assembly sequence; secondary sequencing of prefabricated elements is required during construction to meet the lifting scheme, which leads to increased construction preparation time and risk of worker injury. To enable stacking crews to generate stacking plans rapidly and systematically to improve the on-site lifting efficiency of the components, this paper proposes a storage-location allocation model with two objectives: reduce secondary-sorting workload and increase stacking stability for PC slabs. At the same time, it must match the characteristics of the problem. To prevent the solution from falling into the local optimum during the evolution of the particle swarm optimization algorithm, we introduce an elitist learning strategy, which can improve the solutions when the group converges. Finally, we verify our allocation model and optimization algorithm through example simulations. The simulation results show that, compared with the traditional method, the stacking plans generated by this method have a lower secondary-sorting workload and higher stacking stability when using the same number of storage racks

Optimization of the Stacking Plans for Precast Concrete Slab Based on Assembly Sequence

Precast concrete (PC) slabs are widely used in the assembly of concrete residential buildings. The PC slabs are manufactured at the factory and then arranged in stacks for transport to the construction site for assembly. Currently, optimization of the stacking plans for PC slabs focuses on yard-space utilization and transportation efficiency and rarely considers the assembly sequence; secondary sequencing of prefabricated elements is required during construction to meet the lifting scheme, which leads to increased construction preparation time and risk of worker injury. To enable stacking crews to generate stacking plans rapidly and systematically to improve the on-site lifting efficiency of the components, this paper proposes a storage-location allocation model with two objectives: reduce secondary-sorting workload and increase stacking stability for PC slabs. At the same time, it must match the characteristics of the problem. To prevent the solution from falling into the local optimum during the evolution of the particle swarm optimization algorithm, we introduce an elitist learning strategy, which can improve the solutions when the group converges. Finally, we verify our allocation model and optimization algorithm through example simulations. The simulation results show that, compared with the traditional method, the stacking plans generated by this method have a lower secondary-sorting workload and higher stacking stability when using the same number of storage racks

Detailed Design of Special-Shaped Steel Structures Based on DfMA: The BIM-FEM Model Conversion Method

(1) This paper, based on the characteristics of complex steel structures as well as difficult points in the process of their detailed design, introduces the product design concept of DfMA (Design for Manufacturing and Assembly) from the manufacturing industry and studies the detailed design method of BIM-FEM model conversion. The BIM software Revit (2020) is used as the basis for the BIM detailed design of the project, which achieves the purpose of rapid modeling and provides a detailed design model basis for finite element analysis. (2) Utilizing the Revit API and C# for secondary development as the technical means, this approach involves converting the geometric entity model described by CSG-Brep into an APDL stream. This creates an interface with the finite element analysis software ANSYS (12.0) to implement the detailed design of BIM-FEM model conversion, optimizing the algorithm for converting complex analysis models that require high precision for special-shaped steel structures. (3) This research addresses issues such as the disconnection between the design, manufacturing, and construction of special-shaped steel structures, providing support for design decisions. Moreover, it enhances the detailed design method by improving the standardization of special-shaped components under the condition of design diversity. (4) These studies provide sustainability for engineering design, manufacturing, and construction projects, enabling the maximization of benefits and product lifecycle management (PLM) through these projects. (5) Finally, a case study analysis was conducted on the Wuhan City New Generation Weather Radar Construction Project, designed by the Central South Architectural Design Institute (CSADI), to verify the detailed design of BIM-FEM model conversion. This proved the scientific validity, practicality, and necessity of this research

The reporting of prognostic prediction models for obstetric care was poor: a cross-sectional survey of 10-year publications

Abstract Background To investigate the reporting of prognostic prediction model studies in obstetric care through a cross-sectional survey design. Methods PubMed was searched to identify prognostic prediction model studies in obstetric care published from January 2011 to December 2020. The quality of reporting was assessed by the TRIPOD checklist. The overall adherence by study and the adherence by item were calculated separately, and linear regression analysis was conducted to explore the association between overall adherence and prespecified study characteristics. Results A total of 121 studies were included, while no study completely adhered to the TRIPOD. The results showed that the overall adherence was poor (median 46.4%), and no significant improvement was observed after the release of the TRIPOD (43.9 to 46.7%). Studies including both model development and external validation had higher reporting quality versus those including model development only (68.1% vs. 44.8%). Among the 37 items required by the TRIPOD, 10 items were reported adequately with an adherence rate over of 80%, and the remaining 27 items had an adherence rate ranging from 2.5 to 79.3%. In addition, 11 items had a report rate lower than 25.0% and even covered key methodological aspects, including blinding assessment of predictors (2.5%), methods for model-building procedures (4.5%) and predictor handling (13.5%), how to use the model (13.5%), and presentation of model performance (14.4%). Conclusions In a 10-year span, prognostic prediction studies in obstetric care continued to be poorly reported and did not improve even after the release of the TRIPOD checklist. Substantial efforts are warranted to improve the reporting of obstetric prognostic prediction models, particularly those that adhere to the TRIPOD checklist are highly desirable

Effects of Cr content on the corrosion behavior of porous Ni–Cr–Mo–Cu alloys in H3PO4 solution

Porous Ni–Cr–Mo–Cu alloys were prepared via reaction synthesis of mixed powders. Electrochemical performance test and weight-loss method were used to evaluate the effects of chromium content in the range of 10 ∼ 30 wt% on the alloys corrosion performance in 30 wt% H _3 PO _4 solution. The microstructure, element valence and phase composition of the porous Ni–Cr–Mo–Cu alloys were characterized via scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS) and x-ray diffraction analysis (XRD), respectively. And the results show that the alloys exhibited serviceable corrosion performance and the corrosion behavior was better than that of pure Ni and Cu. Incremental changes in the chromium contents within a certain range enhanced the corrosion resistance of the alloys. These alloys with 30 wt% chromium exhibited excellent anti-corrosion ability in the H _3 PO _4 solution. The electrochemical test displayed that the double capacitive loops of the alloys in the H _3 PO _4 solution increased with the chromium content; at chromium content of 30 wt%, the charge transfer resistance and activation energy were 1123 Ω and 74.10 kJ mol ^−1 , respectively. The possible corrosion-inhibition mechanism was examined by XPS, which may be owing to the formation of MoO _x (x = 1, 2, 3) and Cr _2 O _3 passivation layers in the H _3 PO _4 solution, which prevent further corrosion in acid environments

Virtual Screening and Structure-Based Discovery of Indole Acylguanidines as Potent β-secretase (BACE1) Inhibitors

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