A study on horizontal stud welding by using steel stud for flat welding

ABSTRACT

In recent years, manufacturing sites have strongly requested for the steel stud with large diameter to be welded in the horizontal position, which is difficult because of gravity. In this study, the steel stud of 19 mm in diameter was welded horizontally to the mild steel plate by using ferrule for usage in flat position. As results two kinds of weld defect were observed; lack of fusion and blowhole. The former occurred in the welding condition of too small or too large heat input, and the latter did in the range of longer arc time. Therefore, the suitable welding condition could be found in the large current and shorter arc time. When the areal ratio of weld defect to the cross section of stud was lower than 10 percent, the welded joint had enough statical strength.     

Simplified protocol for detection of protein-ligand interactions via surface-enhanced resonance Raman scattering and surface-enhanced fluorescence

A simple and effective protocol for detections of protein-protein and protein-small molecule interactions has been developed. After interactions between proteins and their corresponding ligands, we employed colloidal silver staining for producing active substrates for surface-enhanced Raman scattering (SERS) and surface-enhanced fluorescence (SEF). Tetramethylrhodamine isothiocyanate (TRITC) and Atto610 were used for both Raman and fluorescent probes. We detected interactions between human IgG and TRITC-anti-human IgG, and those between avidin and Atto610-biotin by surface-enhanced resonance Raman scattering (SERRS) and SEF. The detection limits of the proposed SERRS-based method are comparable to those of the proposed SEF-based one, 0.9 pg/mL for anti-human IgG and 0.1 pg/mL for biotin. This protocol exploits several advantages of simplicity over other SERS and SEF-based related methods because of the protein staining-based strategy for silver nanoparticle assembling, high sensitivity from SERRS and SEF, and high stability in photostability comparing to fluorescence-based protein detections. Therefore, the proposed method for detection of protein-ligand interactions has great potential in high-sensitivity and high-throughput chip-based protein function determination.     

Analytical technique for label-free multi-protein detection based on Western blot and surface-enhanced Raman scattering

We have developed a new analytical procedure for label-free protein detection designated "Western SERS", consisting of protein electrophoresis, Western blot, colloidal silver staining, and surface-enhanced Raman scattering (SERS) detection. A novel method of silver staining for Western blot that uses a silver colloid, an excellent SERS-active substrate, is first proposed in the present study. During the process of silver staining, interactions between proteins and silver nanoparticles result in the emergence of SERS of proteins. In the present study, we use myoglobin (Mb) and bovine serum albumin (BSA) as model proteins. From different protein bands on a nitrocellulose (NC) membrane, we have observed surface-enhanced resonance Raman scattering (SERRS) spectra of Mb and SERS spectra of BSA. The proposed technique offers dual advantages of simplicity and high sensitivity. On one hand, after the colloidal silver staining, we can detect label-free multi-proteins directly on a NC membrane without digestion, extraction, and other pretreatments. On the other hand, the detection limit of the Western SERS is almost consistent with the detection limit of colloidal silver staining, and the SERRS detection limit of Mb is found to be 4 ng/band. This analytical method, which combines the technique of protein separation with SERS, may be a powerful protocol for label-free protein detection in proteomic research.     

Cryogenic optical measurements of 12-segment-bonded carbon-fiber-reinforced silicon carbide composite mirror with support mechanism

A 720 mm diameter 12-segment-bonded carbon-fiber-reinforced silicon carbide (C/SiC) composite mirror has been fabricated and tested at cryogenic temperatures. Interferometric measurements show significant cryogenic deformation of the C/SiC composite mirror, which is well reproduced by a model analysis with measured properties of the bonded segments. It is concluded that the deformation is due mostly to variation in coefficients of thermal expansion among segments. In parallel, a 4-degree-of-freedom ball-bearing support mechanism has been developed for cryogenic applications. The C/SiC composite mirror was mounted on an aluminum base plate with the support mechanism and tested again. Cryogenic deformation of the mirror attributed to thermal contraction of the aluminum base plate via the support mechanism is highly reduced by the support, confirming that the newly developed support mechanism is promising for its future application to large-aperture cooled space telescopes.     

Multivariate curve resolution analysis on the multi-component water sorption process into a poly(2-methoxyethyl acrylate) film

In our previous study, sorption process of water into a biocompatible polymer film, poly(2-methoxyethyl acrylate) (PMEA) was monitored by time-resolved in situ attenuated total reflection infrared (ATR-IR) spectroscopy [S. Morita, et al., Langmuir 23, 3750 (2007)]. In the present study, noisy and heavily overlapped O-H stretching vibrational bands of diffusing water have been analyzed from the series spectra where the spectral shapes change irregularly with time. In spite of these complications, a powerful spectral analysis technique, multivariate curve resolution (MCR) by means of alternating least squares (ALS), yielded smooth and meaningful pure component spectra and detailed kinetic sorption profiles of each component, excluding noise. Ordinary smoothing techniques and Gaussian curve fitting would not achieve these significant results. The quantification of the kinetic parameters such as amplitudes (a) and relaxation time constants (tau) is significant for the systematic development of biocompatible materials and also for revealing the mechanisms of biocompatibility of a material. Moreover, the ratios of coefficients of each component at saturation corresponded well to the values obtained by Tanaka et al. measured by gravimetric analysis. This study is the first to report the detailed concentration profile of each water component whose sorption kinetics is discussed comprehensively.     

Some properties of boronized layers on steels with direct diode laser

Boronized layer on steel is known to be formed by thermal diffusion of boron into the surface of steel improving corrosion-erosion resistant properties. Boronizing is carried out at temperatures ranging from 800 °C to 1050 °C and takes from one to several hours. There is one problem in this process, however, that the structure and properties of the base material are influenced considerably by the high temperature and long time of treatment. In order to avoid the aforementioned drawbacks of pack boronizing and laser-assisted boronizing, a better way is to activate the pack boronizing media and the workpiece with a high density power. The laser boronizing processes do not change the properties of the base material. In this study, the effect of laser characteristics was examined on the laser boronizing of carbon steel. After laser boronizing, the microstructure of the boride layer was analysed with an optical microscope and X-ray diffractometer (XRD). The mechanical properties of borided layer are evaluated using Vickers hardness tester and sand erosion tester. Results showed that the boride layer was composed of FeB and Fe₂B with thickness ranging 200-300 μm. The laser boronizing process did not change the properties of the base material.     

Thin-Film Thermoelectric Modules for Power Generation Using Focused Solar Light

We demonstrated the fabrication of thin-film thermoelectric generators and evaluated their generation properties using solar light as a thermal source. Thin-film elements of Bi_0.5Sb_1.5Te₃ (p-type) and Bi₂Te_2.7Se_0.3 (n-type), which were patterned using the lift-off technique, were deposited on glass substrates using radiofrequency magnetron sputtering. After annealing at 300°C, the average Seebeck coefficients of p- and n-type films were 150???V/K and ?104???V/K, respectively, at 50°C to 75°C. A cylindrical lens was used to focus solar light to a line shape onto the hot side of the thin-film thermoelectric module with 15 p?Cn junctions. The minimum width of line-shaped solar light was 0.8?mm with solar concentration of 12.5 suns. We studied the properties of thermoelectric modules with different-sized p?Cn junctions on the hot side, and obtained maximum open voltage and power values of 140?mV and 0.7???W, respectively, for a module with 0.5-mm p?Cn junctions. The conversion efficiency was 8.75?×?10^?4%, which was approximately equal to the value estimated by the finite-element method.     

Microplastics contamination in tidelands of the Osaka Bay area in western Japan

Recently, researchers have been examining the actual state of microplastics contamination in the environment. However, pollution in high biodiversity environments such as tidelands has not been sufficiently investigated. Therefore, to assess the actual level of microplastics pollution therein, we conducted a survey of the tidelands of Osaka Bay in Japan to develop a model that included basins in urban and suburban areas. We quantified the levels of microplastics in the mud from four of Osaka Bay's tidelands and detected them based on three inhabitants of the main river estuary tideland, namely, bivalves (Corbicula japonica), crabs (Chiromantes dehaani) and a tufted duck (Aythya fuligula). Microplastics ranging in size from 300 μm to 5 mm were targeted, and the results indicated that the concentration of microplastics in the mud tended to increase with tideland proximity to an urban area where the density of the human population was the highest. Microplastics were detected in 10% of the bivalves and 6.7% of the crabs (n = 30 in both cases), and eight pieces of microplastics were detected in the stomach of one tufted duck. These results indicate that the mud in tidelands near urban areas had more microplastics. In addition, the results suggest that microplastics contamination levels may be higher in higher order predators in the food web.     

Purification and characterization of a monoacylglycerol lipase from Pseudomonas sp. LP7315

A monoacylglycerol lipase (MGL) was purified from Pseudomonas sp. LP7315 by ammonium sulfate precipitation, anion-exchange chromatography, and preparative electrophoresis. The purified enzyme was homogeneous on SDS-PAGE with a molecular mass of 59 kDa. Its hydrolytic activity was confirmed to be specific for monoglycerides: the enzyme did not hydrolyze di- and triglycerides. MGL was found to be stable even after 1-h incubation at 65 degrees C. The optimum pH for monopalmitin hydrolysis was approximately 8. The hydrolytic activity depended not only on temperature and pH but also on the type of monoglyceride used. MGL also catalyzed monoglyceride synthesis at 65 degrees C in a solvent-free two-phase system, in which fatty acid droplets were dispersed in the glycerol phase with a low water content. The synthetic reaction proceeded at a constant rate for approximately 24 h and approximately reached an equilibrium after 48 h of reaction. The initial rate and equilibrium yield of the synthetic reaction depended on the type of fatty acid used as the substrate.