Accurate fluid-structure interaction computations using elements without mid-side nodes

The paper proposes a new analysis method for fluid-structure problems, which has nodal consistency at the fluid-structure interface and its calculation efficiency and accuracy are high. The incompressible viscous fluid analysis method using the P1-P1 element based on SUPG/PSPG developed by Tezduyar et al. is used for fluid analysis, while the high-accuracy analysis method based on EFMM developed by the authors is adopted for structure analysis. As the common feature of these methods, it is possible to analyze a fluid or a structure rather accurately by using the first-order triangular or tetrahedral elements. In addition, variables are exchanged exactly at the common nodes on the fluid-structure boundary without deteriorating accuracy and calculation efficiency due to the interpolation of variables between nodes. The present method is applied to a fluid-structure interaction problem by simulating the deformation of a red blood cell.     

Microstructural changes and fracture behavior of CF8M duplex stainless steels after long-term aging

Microstructural changes and fracture behavior in cast CF8M duplex stainless steel after aging at 300–450°C for 300–10?000 h have been investigated. Both, optical microscopical and transmission electron microscopical analyses, hardness and ferrite content measurements have been carried out in this study. Strengthening and aging phenomena of the ferrite phase have been identified by hardness measurements. Spinodal decomposition and heterogeneous precipitation of G-phase were found to be responsible for strengthening of the ferrite phase after aging with a temper parameter (see Appendix A) in the range ca. 1.8–4.5. Three different fracture modes, dimples, cleavage and α/γ grain boundary separation, have been observed for Charpy V-notch and CT test specimens fractured at 20°C.     

Linolenic Acid as the Main Source of Acrolein Formed During Heating of Vegetable Oils

Acrolein, which is an irritating and off-flavor compound formed during heating of vegetable oils, was estimated by the gas–liquid chromatography (GLC). Several vegetable oils such as high-oleic sunflower, perilla, rapeseed, rice bran, and soybean oils were heated at 180 °C for 480 min and then the concentration of acrolein in the head space gas was determined by GLC. The formation of acrolein was greatest in perilla oil among the tested oils, while it was much lower in rice bran oil and high-oleic sunflower oil. There was a good correlation between the level of acrolein and linolenate (18:3n-3) in the vegetable oils. To investigate the formation of acrolein from linolenate, methyl oleate, methyl linoleate, and methyl linolenate were also heated at 180 °C, and the amounts of acrolein formed from them were determined by GLC. The level of acrolein was the greatest in methyl linolenate. Acrolein was also formed from methyl linoleate, but not from methyl oleate. Acrolein in vegetable oils may be formed from polyunsaturated fatty acids, especially linolenic acid but not from glycerol backbone in triacylglycerols.     

The effect of organic additives in electrodeposition of Co from an amide-type ionic liquid

The effect of organic additives, coumarin and thiourea (TU), on the electrodeposition of cobalt (Co) was investigated in an amide-type ionic liquid, 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)amide (BMPTFSA), containing Co(TFSA)₂ as a Co source. In case of addition of coumarin, the deposition potential of Co shifted to the positive side while there was no change in the coordination environment of Co²⁺. However, the surface morphology was changed by addition of coumarin, suggesting the specific adsorption of coumarin on the surface of electrode. On the other hand, the deposition potential of Co shifted to the more positive side by addition of TU, probably due to the change in the coordination environment of Co²⁺ from [Co(TFSA)₃]⁻ to [Co(TU)₄]²⁺. The diffusion coefficient of [Co(TU)₄]²⁺ was determined as 7.2 × 10⁻⁸ cm² s⁻¹ at 27 °C by chronoamperometric method. The surface morphology of electrodeposit obtained from the electrolyte with TU was flat and less granular as compared to that without TU.     

Stop and go extraction tips for matrix-assisted laser desorption/ionization,nanoelectrospray, and LC/MS sample pretreatment in proteomics

Proteomics is critically dependent on optimal sample preparation. Particularly, the interface between protein digestion and mass spectrometric analysis has a large influence on the overall quality and sensitivity of the analysis. We here describe a novel procedure in which a very small disk of beads embedded in a Teflon meshwork is placed as a microcolumn into pipet tips. Termed Stage, for STop And Go Extraction, the procedure has been implemented with commercially available material (C18 Empore Disks (3M, Minneapolis, MN)) as frit and separation material. The disk is introduced in a simple and fast process yielding a convenient and completely reliable procedure for the production of self-packed microcolumns in pipet tips. It is held in place free of obstacles solely by the narrowing tip, ensuring optimized loading and elution of analytes. Five disks are conveniently placed in 1 min, adding <0.1 cent in material costs to the price of each tip. The system allows fast loading with low backpressure (>300 micro/min for the packed column using manual force) while eliminating the possibility of blocking. The loading capacity of C18-StageTips (column bed: 0.4 mm diameter, 0.5 mm length) is 2-4 microg of protein digest, which can be increased by using larger diameter or stacked disks. Five femtomole of tryptic BSA digest could be recovered quantitatively. We have found that the Stage system is well-suited as a universal sample preparation system for proteomics.     

Irreversible membrane fouling during ultrafiltration of surface water

For more efficient use of membranes, the control of irreversible membrane fouling, which can be defined as fouling requiring chemical reagents to be mitigated, is of importance. In this study, irreversible fouling caused by constituents in surface water was investigated, based on a long-term pilot scale study. The membrane employed was a low-pressure hydrophobic ultrafiltration (UF) membrane made of polysulfone and having a molecular weight cutoff of 750,000 Da. Various chemical reagents were examined to overcome the irreversible fouling that had developed through 5 months of continuous filtration. Among the tested cleaning reagents, alkaline (NaOH) and oxidizing reagent (NaClO) showed good performance in the restoration of membrane permeability, which implied that organic matter played an important role in the development of the irreversible fouling in this study. Chemical analysis, adsorptive fractionation methods, fluorescence excitation-emission matrix (EEM) and Fourie-transformed infra-red (FTIR) spectra analysis were applied to elucidate which fraction of organic matter caused the irreversible fouling. All of the analysis indicated that polysaccharide-like organic matter was responsible for the evolution of the irreversible fouling. In addition to organic matter, presumably iron and manganese also contributed to the irreversible fouling to some extent.     

Effect of color attributes on the buying decision model for Durio zibethinus L.

Printed images of food products appearing on packaging usually include vivid colors in order to draw the attention of customers and influence their buying decisions on the product. Buying decisions on Durio zibethinus L. or Durian cv. Monthong are not instantaneous. Packaging designers and marketers need to understand how color stimuli impact the customer's buying decision process. The color attributes of durian images, such as hue, saturation, and intensity based on HSI color system were evaluated for examining the color and generating stimuli. A psychophysical experiment was conducted based on the feelings of “deliciousness,” “attractiveness,” and “naturalness” from the packaging, as these feelings impact buying decisions. Multivariate analysis of variance (MANOVA) indicated that saturation had a significant effect on all the feelings that influence buying decisions. The multiple regression analysis showed that the relationships between “Attractiveness of Flesh (Att‐F)” and “Deliciousness of Flesh (Del‐F)” and the buying decision were significant. In addition, the relationship between the saturation levels set by Adobe Photoshop and Chroma difference (ΔC*_ab) indicated that the appropriate Chroma difference (ΔC*_ab) should be in the range of 21 to 28 to achieve the highest satisfaction and a predicted probability of buying of more than 90%.     

Physical and electrochemical characterization of ionic liquids based on quaternary phosphonium cations containing a carbon–carbon double bond

Physical and electrochemical characterizations of novel two ionic liquids based on quaternary phosphonium cations containing an unsaturated carbon–carbon bond (triethyl(4-pentenyl)phosphonium and allyltributylphosphonium cations) are presented in this report. It was found that both unsaturated phosphonium cations gave low-melting salts in combination with a bis(trifluoromethylsulfonyl)amide anion. The thermogravimetric analysis suggested that the unsaturated phosphonium ionic liquids showed higher thermal stability than those of the corresponding saturated phosphonium ILs. The unsaturated phosphonium ionic liquids also exhibited relatively low viscosity and high conductivities when compared to those of the corresponding saturated phosphonium ionic liquids. These results indicate an improving effect of introducing a carbon–carbon double bond into the phosphonium cations on both the thermal stability and the transport property. The voltammetric measurements suggested that the triethyl(4-pentenyl)phosphonium-based ionic liquid showed a high cathodic stability, enabling the deposition and dissolution of metallic lithium in the phosphonium ionic liquid system.