Influence of Bionic Circular Groove Blade Surface on Wear Performance

In order to improve the anti-wear performance of a double-vane self-priming centrifugal pump during two-phase flow transfer, the construction of a streamline groove structure at the outlet end of the suction side of the vane, based on the bionic principle, is proposed. Different pump characteristics are analysed to investigate the effect of different bionic groove spacing on the resistance to particle wear and the mechanism of improvement of the bionic grooves. The results show that the effect of the bionic blades on the hydraulic characteristics of the pump is within the allowable error (±1.4%). The circular groove structure with different spacing produces a difference in the pressure distribution on the blade. At the same particle concentration, with the increase in the groove spacing distance, the average wear of the blades first decreases and then increases; the average wear rate at the spacing of 7 mm is the smallest. At a particle concentration of 90 kg/m3, the average wear rate at a groove spacing of 7 mm is ~0.63 × 10−4 kg/s∙m2, and the wear area is mainly found in the middle of the blade. The reason why the bionic blade improves the anti-wear performance of the pump is due to the reverse vortex zone in the groove, which changes the particle trajectory and collision frequency. The bionic grooves with a diameter of 2 mm and a spacing of 7 mm significantly reduce the average wear rate of the pump at different particle concentrations, while maintaining hydraulic performance

Impact Assessment of Asphalt Concrete in Geogrid-Reinforced-Pile-Supported Embankment During High-Speed Train Traffic

Railroad structural behaviour is a significant factor for safety and comfort during high-speed train operation. Intending to improve railway performance, increase its bearing capacity, and reduce vibrations induced by train passage, asphalt concrete has become a material to be integrated into railway construction. Despite several studies evaluating asphalt concrete effect on the railway mechanical behaviour, its impact assessment remains poorly understood. This study investigates the impact of asphalt concrete material in the geogrid-reinforced-pile-supported embankment structure subjected to high-speed train moving. A 3D nonlinear finite element model was developed to simulate Harbin (Dalian (China) instrumented railroad test section accurately. The high-speed train moving load was modelled as a transitory dynamic load via a user-defined subroutine 3D load in which the track irregularity is incorporated. The established model was effectively validated by the vibration acceleration and stress measured in the field test section. The asphalt concrete viscoelasticity behaviour was incorporated into the 3D geogrid-reinforced-pile-supported embankment finite element model through the Prony series to characterise its mechanical response better. The impact of asphalt concrete material in maintaining a low and constant structural vibration, regardless of train weight level, moving speed variations, and weather conditions were investigated, analysed and discussed

Preparation and Modification Technology Analysis of Ionic Polymer-Metal Composites (IPMCs)

As a new type of flexible smart material, ionic polymer-metal composite (IPMC) has the advantages of being lightweight and having fast responses, good flexibility, and large deformation ranges. However, IPMC has the disadvantages of a small driving force and short lifespan. Based on this, this paper firstly analyzes the driving mechanism of IPMC. Then, it focuses on the current preparation technology of IPMC from the aspects of electroless plating and mechanical plating. The advantages and disadvantages of various preparation methods are analyzed. Due to the special driving mechanism of IPMC, there is a problem of short non-aqueous working time. Therefore, the modification research of IPMC is reviewed from the aspects of the basement membrane, working medium, and electrode materials. Finally, the current challenges and future development prospects of IPMC are discussed

Preparation and Modification Technology Analysis of Ionic Polymer-Metal Composites (IPMCs)

As a new type of flexible smart material, ionic polymer-metal composite (IPMC) has the advantages of being lightweight and having fast responses, good flexibility, and large deformation ranges. However, IPMC has the disadvantages of a small driving force and short lifespan. Based on this, this paper firstly analyzes the driving mechanism of IPMC. Then, it focuses on the current preparation technology of IPMC from the aspects of electroless plating and mechanical plating. The advantages and disadvantages of various preparation methods are analyzed. Due to the special driving mechanism of IPMC, there is a problem of short non-aqueous working time. Therefore, the modification research of IPMC is reviewed from the aspects of the basement membrane, working medium, and electrode materials. Finally, the current challenges and future development prospects of IPMC are discussed

Effect of the Bionic Circular Groove Non-Smooth Structure on the Anti-Wear Performance of the Two-Vane Pump

The characteristics of the material transported by the two-vane pump can cause the impeller to wear out, leading to a deterioration in hydraulic efficiency. Appropriately, the research goal of this paper is to consolidate the anti-wear performance of the two-vane pump conveying a solid-liquid two-phase flow. Based on the bionic principle and the anti-wear structure of blood clams, the circular non-smooth structure adapted from blood clams is arranged in the wear-prone area. Through numerical simulation, we compare the main indexes of the pump: the head, the pressure distribution, the vortex pressures, and the average wear rate, to reveal the wear resistance mechanism of circular non-smooth structures. The results illustrate that the use of a circular non-smooth structure does not modify the external characteristics of the pump; the pressure distribution inside the impeller is similarly consistent, and the vortex pressures are all approximately the same. The average wear rate is higher when the diameter of the circular non-smooth structure is either 0.25 mm or 0.30 mm, and the simulation results are poor. At a diameter of 0.20 mm, the average wear rate of circular non-smooth blades is at its lowest point. The circular non-smooth surface structure causes impurities to be “caught” by the vortex zone and not freely struck against the wall, resulting in the particles migrating away from the blade

Effect of the Bionic Circular Groove Non-Smooth Structure on the Anti-Wear Performance of the Two-Vane Pump

The characteristics of the material transported by the two-vane pump can cause the impeller to wear out, leading to a deterioration in hydraulic efficiency. Appropriately, the research goal of this paper is to consolidate the anti-wear performance of the two-vane pump conveying a solid-liquid two-phase flow. Based on the bionic principle and the anti-wear structure of blood clams, the circular non-smooth structure adapted from blood clams is arranged in the wear-prone area. Through numerical simulation, we compare the main indexes of the pump: the head, the pressure distribution, the vortex pressures, and the average wear rate, to reveal the wear resistance mechanism of circular non-smooth structures. The results illustrate that the use of a circular non-smooth structure does not modify the external characteristics of the pump; the pressure distribution inside the impeller is similarly consistent, and the vortex pressures are all approximately the same. The average wear rate is higher when the diameter of the circular non-smooth structure is either 0.25 mm or 0.30 mm, and the simulation results are poor. At a diameter of 0.20 mm, the average wear rate of circular non-smooth blades is at its lowest point. The circular non-smooth surface structure causes impurities to be “caught” by the vortex zone and not freely struck against the wall, resulting in the particles migrating away from the blade

Scoping Review and Bibliometric Analysis of the Most Influential Publications in Achalasia Research from 1995 to 2020

Objective. To identify and evaluate characteristics of the most influential articles in achalasia research during the period 1995-2020. Methods. Articles in Scopus, Web of Science Core Collection (WoSCC), and PubMed were scanned from 1995 to 2020 with achalasia as the keyword. We retrieved the articles that met all criteria by descending order after using EndNote to remove the duplicated references. Our bibliometric analysis highlighted publication year, country, journals, and networks of keywords. Results. Fifteen percent of the top 100 most-cited articles were published in Annals of Surgery. They were performed in 15 countries, and most (n=55) were from the USA. The number of citations of the 482 articles ranged from 30 to 953, 38 of which had been published in American Journal of Gastroenterology. Those articles were from 31 countries, and most of the studies (n=217) had been performed in the USA. Most of articles (n=335) were clinical research. Treatments were hotspots in the field of achalasia in the past years. The most influential title words were “achalasia,” “esophagomyotomy,” “pneumatic dilation,” and “lower esophageal sphincter.” Conclusion. Our study offers a historical perspective on the progress of achalasia research and identified the most significant evolution in this field. Results showed treatment was the most influence aspect in achalasia

Influence of NaCl on lipid oxidation and endogenous pro-oxidants/antioxidants in chicken meat

The aim of this study was to investigate the effect of different content of sodium chloride (NaCl) on lipid oxidation of chicken breast meat and the endogenous pro-oxidants/antioxidants contributing to lipid oxidation. The results demonstrated that NaCl could promote lipid oxidation in chicken meat until NaCl content reached up to 4.5%. Generation of reactive oxygen species and H2O2 initiated by NaCl might be responsible for the increased lipid oxidation, and lipoxygenase activity was highly correlated with oxidative stability of meat. However, oxidation of lipid was not negatively correlated with superoxide dismutase, glutathione peroxidase and catalase activity. The sensory evaluation by electronic nose showed an increase in saltiness, richness and umami taste and a decrease in bitterness with increasing NaCl content, but there was no significant change in these sensory ratings when the NaCl content exceeded 3.0%. The volatile compounds obtained by gas chromatography-mass spectrometry (GC-MS) showed that NaCl increased the formation of most flavor components in chicken meat. This study could provide a reference for the control of lipid oxidation in meat and development of low salt meat products

Correlated Rectification Transport in Ultranarrow Charged Nanocones

Using molecular dynamics simulations, we reveal ion rectification in charged nanocones with exit diameters of 1–2 nm. The simulations exhibit an opposite rectification current direction than experiments performed in conical channels with exit diameters larger than 5 nm. This can be understood by the fact that in ultranarrow charged cones screening ions are trapped close to the cone tip at both field directions, which necessitates them to be released from the cone in a correlated multi-ion fashion. Electroosmosis induced by a unidirectional ion flow is also observed

Efficacy of Probiotic Supplementation Therapy for <i>Helicobacter pylori</i> Eradication: A Meta-Analysis of Randomized Controlled Trials - Fig 2

<p><b>A</b> risk of bias graph, <b>B</b> risk of bias summary (“+”low risk; “?”, unclear risk; “-”, high risk).</p