This study examined the relationship between the microstructure of the base metal and its corrosion behavior using abrasive water-jet treatment （AWT）. The changes in the surface configuration and ...microstructural features of carbon steel obtained at different standoff distances from AWT were compared to those of blast treatment. The surface characteristics of the specimens were assessed for their roughness and microstructure. The relationship between roughness and corrosion behavior was the opposite result of conventional literature and showed that factors other than roughness among surface properties have a greater influence on the corrosion resistance for specimens treated in this study. The experimental results showed that the smaller the standoff distance, the changes in microstructures induced from the increased plastic deformation layers during the AWT became apparent. As the energy arriving at the substrate during the AWT increased, we observed the increased surface hardening and the reduced grain size on the plastic deformation sections, which resulted in improved corrosion resistance. Therefore, it was demonstrated that the surface cleaning of AWT has a positive effect on the corrosion properties of the base materials, which maintained their lifespan.
The triglycerides composition and their respective abundance in 34 vegetable lipidic samples from 25 different natural products, most of which were edible lipid samples, were examined using ...ultra-high efficiency / low-pressure supercritical fluid chromatography with 5 tandem columns filled with core-shell particles, hyphenated to mass spectrometry with atmospheric pressure chemical ionization (UHE/LPSFC-APCI-MS). Thanks to the high efficiency and high selectivity of this chromatographic method joint to the sensitivity of mass spectrometry, 94 different triglycerides were identified and quantified, comprising low-abundance triglycerides, but also structurally close ones, as regio-isomers and geometrical (cis/trans) isomers. Relative quantification results enabled to construct hierarchical cluster analyses to compare the level of similarity between samples. Thanks to that, samples from identical or different vegetable sources were compared. Oils from the same source were compared based on the possible refining treatment they had received, allowing to examine the impact of the treatment on the triglyceride content. Then, the quantification results were compared to data previously obtained with the same separation method but with UV or evaporative light-scattering detection with a smaller set of samples.
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•High-resolution chromatograms obtained with supercritical fluids and long columns.•Structural information obtained through mass spectrometric detection.•Resolution of regio-isomeric triglyceride pairs is demonstrated.•Resolution of cis/trans geometrical isomers is demonstrated.•Comparison of 34 edible and non-edible oils and butters to evaluate similarities.
The complexation of allophane nanoparticles with cisplatin, cis-dichlorodiammineplatinum (II) (CDDP) to deliver platinum prodrug into cancer cells was investigated. Using human lung carcinoma (A549) ...cells, profound studies including cellular uptake (endocytosis) analysis of allophane nanoparticle, cell cycle arrest abilities and apoptosis induction profiles were discussed in detail. As well as the features against A549 cells to emerge a promising strategy to enhance their anti-cancer activity and to mitigate side-effects were discussed.
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•The complexation of allophane nanoparticles and CDDP platinum prodrug was examined.•Cellular uptake (endocytosis) analysis of AK70 particles was demonstrated.•Incubation with complex at same CDDP concentration led to moderate apoptosis of A549 cells.
•Desirability functions based on the analysis of 129 probe compounds.•Identification of most versatile stationary phases among 14 column chemistries.•Identification of specialized stationary phases ...for pharmaceuticals.•Identification of specialized stationary phases for natural products.•Investigation of polarity descriptors to understand retention.
When starting a method development in supercritical fluid chromatography (SFC), the first step is usually to screen several stationary phases based on previous experience or simply based on what is available in the laboratory. However, as there are now a large number of stationary phases available for SFC, the choice of an adequate set of columns to rapidly achieve a satisfying result can be difficult. In this project, 16 columns comprising a wide diversity of stationary phases and polarities ranging from the most polar (like bare silica gel) to the least polar (like octadecylbonded-silica) were compared, based on the gradient analysis of 129 probe compounds. The set mostly comprised active pharmaceutical ingredients, natural products and a few metabolites. The columns were ranked with the help of Derringer desirability functions taking account of (i) the number of compounds eluted from the column, (ii) the elution time in a suitable time frame, (iii) the average peak width, (iv) the average peak symmetry and (v) the spreading of retention along the gradient time. The five criteria selected showed no correlation. Overall, it appeared that those columns that had a high overall score were good for several reasons, like bare silica gel, propanediol-bonded silica or pentabromobenzyloxy-bonded silica. Initially, the columns had been screened with a gradient elution starting from 5% co-solvent and ending with 50% co-solvent in CO2. However, for some most retentive columns like amide-bonded silica, too many compounds remained non-eluted from the column. To examine this column more fairly, a second elution gradient was applied that ended with 100% co-solvent. This proved effective in restoring good overall performance through the elution of the most polar compounds.
The effects of a newly developed nozzle type, with divergent flow, and abrasive particle size on the surface preparation properties of steel substrate using abrasive water-jet treatment (AWT) were ...analyzed. The corrosion and chloride removal efficiencies were evaluated by applying this technique to parts of severely corroded steel structures. The evaluation of the surface characteristics of the treated specimens included analysis of the treatment area, maximum erosion depth, surface roughness profile, and residual abrasive material quantity. The corrosion removal efficiency was assessed using surface salinity measurements and SEM-EDX analysis. The experimental results demonstrated that the application of the developed divergent nozzle and smaller abrasive particle sizes in the AWT process resulted in an expanded treatment range and effective prevention of excessive erosion depth and surface roughness. Additionally, ultra-high-pressure water with abrasives completely eliminated corrosion products and chlorides present on both the surface and interiors of the corroded steel surface, achieving a cleanliness level exceeding Sa 3. This process prevented the formation of flash rust on the cleaned surface for up to 24 h and prolonged the time before the reoccurrence of corrosion on the treated surface. To summarize, the AWT with a divergent nozzle and smaller abrasive particles creates the most ideal surface preparation characteristics for subsequent coating and provides higher surface cleanliness suitable for practical engineering applications.
•The impact of nozzle type and abrasive particle size in AWT on the surface properties of steel plates was analyzed.•AWT with divergent nozzle and smaller abrasives expanded treatment range and prevented excessive erosion depth and roughness.•AWT ensures Sa3 cleanliness on corroded structures, eliminating corrosion, chlorides, and preventing flash rust for 24 hours.
Clay minerals are mainly used around traditional cosmetics and industrial products, but currently their target application is continuously expanding into pharmaceutical industry and tissue ...engineering. To broaden the knowledge of in vitro cytotoxicity of allophane nanoparticles against human cancer cells, the cytotoxicity of both natural and synthetic allophane nanoparticles for cultured human alveolar basal epithelial (A549) cells was examined. For both natural and synthetic allophones, the A549 cell viability was maintained at >70% for concentration up to 3160μg/mL, implying higher biocompatibility of allophane nanoparticles as compared with that of hectorite nanoparticles. The cell adhesion kinetics coupled with cytotoxic characteristics against A549 cells was analyzed using quartz crystal microbalance (QCM) technique to distinguish the dynamic cell adhesion signatures.
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•The cytotoxicity of allophane nanoparticles was examined.•Higher biocompatibility of allophane for A549 cells was demonstrated.•The estimated IC50 value of hectorite for A549 was 105μg/mL.
There are some examples of studies focused on the slip coefficients in high-strength bolted frictional joints with various holes. It found that the slip coefficients in the joints with oversized ...holes and slotted holes were less than the coefficients in the joints with normal holes. However, in Japan, there is no rule regarding the slotted holes, and the use is not accepted. In this study, FEM was carried out and the mechanism by which the slip coefficients were decreased was investigated in the joints with slotted holes and oversized holes varied the slip/yield resistance ratio and the washer thickness. Therefore, the mechanism of the slip coefficient reduction is clarified.
In these days, it has been reported that some of steel bridges are deteriorated due to corrosion of the girder ends. Since the evaluation method of the load carrying capacity of the girder ends with ...corrosion is not established, understanding of mechanical property and ultimate strength of the girder ends is required from the viewpoint of repair works. In this paper, the load carrying capacity of the girder ends with corrosion of Highway Bridges is studied based on FE analysis. In particular, the influence of corrosion area and location of the girder ends to its load carrying capacity are discussed focusing on the height and length of the corrosion area, the size of the sole plate and so on.
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