Moiré interferometry measurements of neartip deformation in inhomogeneous elasticplastic fracture specimens

Moiré interferometry was used for direct measurements of the crack tip behavior in the homogeneous compact tension (CT) specimens of A533B and HT80 steels, and in electron-beam welded inhomogeneous CT specimens of the two materials. These two materials have considerably different yield stresses, although their elastic properties are the same. Five types of homogeneous and inhomogeneous specimens were used in the experiment. Moiré fringe patterns of the five specimen types were directly compared for elastic, elastic-plastic and unloaded stages. Although the global deformations in terms of the load versus COD relations exhibit little inhomogeneity effects, large inhomogeneity effects were observed in the moiré fringe patterns in the elastic-plastic and unloaded stages. The near-tip deformations were also compared with the corresponding HRR singular fields. In a horizontal weld specimen, due to strong hardening in the weld region, the slope of the displacement field does not shift the characteristic HRR field for the A533B or the HT80 steel for increasing load.     

Characterization and hydrogen sorption behaviors of FeNiCr-carbon composites derived from Fe,Ni and Cr-containing polyacrylonitrile fibers prepared by electrospinning method

In order to enhance hydrogen storage capacity of carbonaceous materials through metal modification, FeNiCr-carbon composites were prepared by calcination of Fe, Ni and Cr-containing polyacrylonitrile (PAN) fibers fabricated by electrospinning method. Fe (III), Ni (II) and Cr (III) acetylacetonates (M (acac)_n) were selected as metal sources. Increase of specific surface area and formation of micropores were observed on heat decomposition of M (acac)_n particularly through introduction of steam. Maximal hydrogen content, 1.62 mass%, was obtained at 77 K under 0.8 MPa of hydrogen for a FeNiCr-carbon composite, which contained about 15.5 mass% of metals and had specific surface area of 501 m² g^?1. The hydrogen content exceeded the hydrogen physisorption limit, 2.34 mass% per 1000 m² g^?1, which was calculated on the basis of the commensurate–incommensurate transition with an enhancing factor ρ of 1.126. After hydrogenation at 653 K, no hydrogen desorption peaks were observed for FeNiCr powders derived from M (acac)_n, and one peak at 828 K for a carbonaceous sample prepared from unmodified PAN fibers. From the most promising FeNiCr-carbon composite, another peak was recorded at 752 K in addition to the peak at 828 K. The former would be originated from hydrogen on novel sorption sites additionally created on the composite formation.     

A novel carrier-cooperation scheme with an incentive to offer emergency lightpath support during disaster recovery

Photonic Network Communications - To achieve fast recovery of optical transport networks after a disaster, we investigate a novel scheme enabling cooperation between carriers. Carriers can take...     

Investigation of Tribo-Chemistry by Means of Stable Isotopic Tracers,Part 2: Lubrication Mechanism of Friction Modifiers on Diamond-Like Carbon

A solution of glycerol monooleate (GMO) in polyalphaolefin (PAO) considerably reduced the friction between the steel and the diamond-like carbon (DLC) under boundary conditions. The combination of the material-oil-additive is of importance. Model additives composed of a stable isotope ( ² H or ¹³ C) were employed to trace the additive molecule by time-of-flight secondary ion mass spectroscopy (TOF-SIMS). It was found that the additive interacted with DLC surfaces in the form of an ester. Inclusion of PAO in the boundary film on DLC was found by TOF-SIMS analysis.The utility of the isotopic tracer technique in tribo-chemistry was demonstrated in this study.     

Multi-objective genetic algorithm-based sample selection for partial least squares model building with applications to near-infrared spectroscopic data

In this study, multi-objective genetic algorithms (GAs) are introduced to partial least squares (PLS) model building. This method aims to improve the performance and robustness of the PLS model by removing samples with systematic errors, including outliers, from the original data. Multi-objective GA optimizes the combination of these samples to be removed. Training and validation sets were used to reduce the undesirable effects of over-fitting on the training set by multi-objective GA. The reduction of the over-fitting leads to accurate and robust PLS models. To clearly visualize the factors of the systematic errors, an index defined with the original PLS model and a specific Pareto-optimal solution is also introduced. This method is applied to three kinds of near-infrared (NIR) spectra to build PLS models. The results demonstrate that multi-objective GA significantly improves the performance of the PLS models. They also show that the sample selection by multi-objective GA enhances the ability of the PLS models to detect samples with systematic errors.     

New methodology to obtain a calibration model for noninvasive near-infrared blood glucose monitoring

This paper reports new methodology to obtain a calibration model for noninvasive blood glucose monitoring using diffuse reflectance near-infrared (NIR) spectroscopy. Conventional studies of noninvasive blood glucose monitoring with NIR spectroscopy use a calibration model developed by in vivo experimental data sets. In order to create a calibration model, we have used a numerical simulation of light propagation in skin tissue to obtain simulated NIR diffuse reflectance spectra. The numerical simulation method enables us to design parameters affecting the prediction of blood glucose levels and their variation ranges for a data set to create a calibration model using multivariate analysis without any in vivo experiments in advance. By designing the parameters and their variation ranges appropriately, we can prevent a calibration model from chance temporal correlations that are often observed in conventional studies using NIR spectroscopy. The calibration model (regression coefficient vector) obtained by the numerical simulation has a characteristic positive peak at the wavelength around 1600 nm. This characteristic feature of the regression coefficient vector is very similar to those obtained by our previous in vitro and in vivo experimental studies. This positive peak at around 1600 nm also corresponds to the characteristic absorption band of glucose. The present study has reinforced that the characteristic absorbance of glucose at around 1600 nm is useful to predict the blood glucose level by diffuse reflectance NIR spectroscopy. We have validated this new calibration methodology using in vivo experiments. As a result, we obtained a coefficient of determination, r2, of 0.87 and a standard error of prediction (SEP) of 12.3 mg/dL between the predicted blood glucose levels and the reference blood glucose levels for all the experiments we have conducted. These results of in vivo experiments indicate that if the parameters and their vibration ranges are appropriately taken into account in a numerical simulation, the new calibration methodology provides us with a very good calibration model that can predict blood glucose levels with small errors without conducting any experiments in advance to create a calibration model for each individual patient. This new calibration methodology using numerical simulation has promising potential for NIR spectroscopy, especially for noninvasive blood glucose monitoring.     

Comparative study of activity of cerium oxide at thermal reduction temperatures of 1300–1550 °C for solar thermochemical two-step water-splitting cycle

Thermochemical two-step water-splitting using CeO₂ (cerium oxide) particles was studied to examine oxygen and hydrogen productivity and repeatability at thermal reduction (T-R) temperatures of 1300–1550 °C and water decomposition (W-D) temperatures of 400–1000 °C for the production of hydrogen from water using concentrated solar radiation as the energy source. The temperature dependency of oxygen and hydrogen productivity and the cyclic repeatability of CeO₂ are reported in this paper. The characteristic features of CeO₂ particles in the thermochemical two-step water-splitting cycle are compared with the well-known highly active reactive mediums of zirconia-supported Ni-ferrites (NiFe₂O₄/m-ZrO₂ and NiFe₂O₄/c-YSZ) and unsupported NiFe₂O₄.     

Expression of telomerase activity in human chorion

Telomerase activation is required for cellular immortalization and is found in most malignant tumors. Normal somatic cells are generally telomerase-negative, except for stem cells in renewing tissues. During pregnancy, human trophoblast continues to proliferate and acts as proliferating stem cells for the development of chorion and the formation of placenta. In the present study, a total of 105 chorions from placentas at various weeks of gestation were examined for telomerase activity using the telomeric repeat amplification protocol (TRAP) assay. Twenty-five of 33 (76%) normal early chorions at 5 to 9 weeks gestation were telomerase-positive. Chorions from early spontaneous abortions also exhibited telomerase activity but at a low level. In contrast, only 2 (4%) late chorions at 34 to 41 weeks gestation expressed telomerase activity. Significant telomerase activity was observed in trophoblast cell fractions of chorion, demonstrating trophoblast to be the source of the activity. Expression of human telomerase catalytic subunit (hTRT) was observed in early chorions, but not in late placenta, and there was a close correlation between telomerase activity and hTRT expression. In contrast, expression of human telomerase RNA component (hTR) was observed in both early and late chorions and was not liked to telomerase activity. These findings suggest that telomerase activity in chorion is critically regulated over the course of gestation, associated with hTRT expression. The findings of the present study also appear to support the emerging concept that normal somatic cells with stem cell-like characteristics can express telomerase activity.     

Some Properties of Oxidized Gelatin

Alkali processed inert type gelatin has been oxidized in a controlled stepivise fashion using H₂,0₂. The difference between oxidation degree of gelatin was detected by a simple physical ripening test and potentiometric titration with AgNO₃. The physical ripening was very influenced by pH and the variety of halide. The titration curve has an inflection point and the plot of pAg vs. logarithm of Ag ion concentration gives a straight line.     

Layer-by-layer self-assembled mutilayer films of gold nanoparticles for surface-assisted laser desorption/ionization mass spectrometry

Layer-by-layer (LBL) self-assembled multilayer films of gold nanoparticles (AuNPs) on a silicon wafer were demonstrated to be promising substrates for surface-assisted laser desorption/ionization (SALDI) mass spectrometry (MS) of peptides and environmental pollutants for the first time. LBL multilayer films, (AuNPs/PAHC)n, consisting of alternating layers of ammonium citrate capped AuNPs and poly(allylamine hydrochloride) (PAHC) were prepared on a silicon surface. Silicon plates with aggregated AuNPs were more suitable than those with dispersed AuNPs for the SALDI-MS of peptides. The number of particle layers had a significant effect on the laser desorption/ionization of angiotensin I; the peak intensity of the peptide (molecular ion amount) increased with an increase in the number of layers of AuNPs. As a result, the (AuNPs/PAHC)5 multilayer films increased the sensitivity of the angiotensin I to subfemtomoles and raised the useful analyte mass range, thus making it possible to detect small proteins (a 12 kDa cytochrome c). The signal enhancement when using (AuNPs/PAHC)5 may be due to (i) the high absorption of the UV laser light at 337 nm by the AuNP layers, (ii) the low thermal conductivity due to the AuNPs being covered with a thin monolayer of PAHC, and (iii) the increase in the surface roughness (approximately 100 nm) with the number of AuNP layers. Thus, laser-induced rapid high heating of AuNPs for effective desorption/ionization of peptides is possible. In addition, it was found that (AuNPs/PAHC)5 could be used to extract environmental pollutants (pyrene and dimethyldistearylammonium chloride) from very dilute aqueous solutions with concentrations less than 10(-10) mg/mL, and the analytes trapped in the LBL film could be identified by introducing the film directly into the SALDI mass spectrometer without needing to elute the analytes out of the film.