Measurement of the residual stress in CrN coatings deposited on an Al alloy substrate

Chromium nitride (CrN) coatings were deposited on Al alloy substrates using the arc ion plating method with different bias voltages and different thicknesses. The residual stresses of these samples were measured via x-ray diffraction using the sin2 ψ method because the CrN crystals in the coatings were nonoriented. The stress gradient across the CrN coating was calculated from the curved 2θ-sin2 ψ diagram. In the case of CrN coatings deposited at low bias voltage, the compressive residual stress that formed at the substrate interface was larger than the stress at the surface of the CrN coating. Conversely, in the case of CrN coatings deposited at high bias voltage, the compressive residual stress on the surface of the CrN coating was larger than the stress on the interface with the substrate. In CrN coatings deposited at high bias voltage, very large compressive residual stress on the CrN coating surface decreased with increasing coating thickness

Residual stress measurement of {112}-oriented CrN layers in CrN/Cr multilayer films

In this work, the authors propose and verify a method of measuring the residual stress of {112}-oriented chromium nitride (CrN) layers in CrN/Cr multilayer thin films. The CrN layers of a CrN/Cr multilayer film deposited on a Ti6Al4V substrate by arc ion plating form both a randomly oriented mixed crystal structure and a {112}-oriented structure. Therefore, accurate stress measurement of the CrN layers cannot be performed by applying the sin2ψ x-ray method assuming an isotropic homogeneous material. To overcome this obstacle, the proposed method to measure the residual stress uses four CrN-422 diffractions: at ψ = 0°, 33.56°, 48.19°, and 60.00°. Next, the authors vary the density of Cr droplets on the film surface to evaluate how it affects the residual stress in the CrN/Cr multilayer film. The results indicate that the Cr layer has a residual compressive stress of −350 to −530 MPa and that the two CrN layers have a very large residual compressive stress of −3.5 to −8.2 GPa. In addition, both residual compressive stresses decrease with increasing droplet density

アタラシイ フチャク ヨクセイ ヒョウメン ショリ オ ホドコシタ コウ ヒョウメン エノ フンタイ ノ フチャク キョドウ ノ カイセキ

In this paper, we examined the relationship between surface roughness and particle adhesion behavior by a proposed experiment. Five kinds of SiO2 spherical powders (0.2μm-2.0μm) and stainless steel plates with seven kinds of surface roughness were used for the investigation. The adhesion ratios of SiO2 powders to polished stainless steel plates were measured. The adhesion ratios depend on the surface roughness and the particle diameters. The adhered particles on the steel plate were observed by SEM in order to examine the adhesion mechanism of SiO2 particle on the polished stainless plate substrate. As the result, 0.4-1.0 μm particles were easy to adhere independent of surface roughness and nominal powder diameter. The result indicates that adhesion behavior of powder depends on the adhesion force of 0.4-1.0 μm particles that are changed by the surface roughness of the steel plate

Evaluation of the histological and mechanical features of tendon healing in a rabbit model

Objectives This study aimed to evaluate the histological and mechanical features of tendon healing in a rabbit model with second-harmonic-generation (SHG) imaging and tensile testing. Materials and Methods A total of eight male Japanese white rabbits were used for this study. The flexor digitorum tendons in their right leg were sharply transected, and then were repaired by intratendinous stitching. At four weeks post-operatively, the rabbits were killed and the flexor digitorum tendons in both right and left legs were excised and used as specimens for tendon healing (n = 8) and control (n = 8), respectively. Each specimen was examined by SHG imaging, followed by tensile testing, and the results of the two testing modalities were assessed for correlation. Results While the SHG light intensity of the healing tendon samples was significantly lower than that of the uninjured tendon samples, 2D Fourier transform SHG images showed a clear difference in collagen fibre structure between the uninjured and the healing samples, and among the healing samples. The mean intensity of the SHG image showed a moderate correlation (R2 = 0.37) with Young’s modulus obtained from the tensile testing. Conclusion Our results indicate that SHG microscopy may be a potential indicator of tendon healing

Enhancement in Boiling Heat Transfer for Water Using a Polished Plate Surface

The thermal characteristic of a plate evaporator for boiling water have been experimentally investigated. Stainless-steel plates with five kinds of surface roughness (a mirror-polished surface and four kinds of polished plate surface, F2, F0, F-1, and F-2 polishing) were used for the investigation. The roughness order is F-2 > F-1 > F0 > F2 > mirror. The local boiling heat transfers were measured on the evaporator surface using ten thermocouples inside the evaporator. For a comparison of the heat transfer characteristic of the evaporator, the local boiling heat transfer coefficient was measured when the polishing direction was perpendicular or parallel to the water flow at a range of pressures (0.3–0.4 MPa) and flow rates (20–60 mL/min). The results indicate that the local heat transfer coefficient increased with increasing vapor quality at all surface conditions. For F0 polishing, the heat transfer coefficient on the surface with perpendicular polishing was much larger than that on the surfaces with parallel and mirror polishing. In particular, the heat transfer coefficient of the perpendicularly polished surface (F2 and F0 polishing) was increased six-fold in comparison with that of the mirror surface at a vapor quality of 0.35. However, for the F-1 and F-2 perpendicularly polishing plates, the heat transfer coefficients were smaller than those of the F0 and F2 perpendicularly polishing plates. For the F2 perpendicularly polished plate, heat transfer enhancement was confirmed, along with an increase in the number of bubbling points, on increasing the system pressure. For the polished surface, the heat transfer coefficient increased with increasing flow rate. This indicates that the bubble formation cycle was promoted by an increased flow rate

KaPPA-View4: a metabolic pathway database for representation and analysis of correlation networks of gene co-expression and metabolite co-accumulation and omics data

Correlations of gene-to-gene co-expression and metabolite-to-metabolite co-accumulation calculated from large amounts of transcriptome and metabolome data are useful for uncovering unknown functions of genes, functional diversities of gene family members and regulatory mechanisms of metabolic pathway flows. Many databases and tools are available to interpret quantitative transcriptome and metabolome data, but there are only limited ones that connect correlation data to biological knowledge and can be utilized to find biological significance of it. We report here a new metabolic pathway database, KaPPA-View4 (http://kpv.kazusa.or.jp/kpv4/), which is able to overlay gene-to-gene and/or metabolite-to-metabolite relationships as curves on a metabolic pathway map, or on a combination of up to four maps. This representation would help to discover, for example, novel functions of a transcription factor that regulates genes on a metabolic pathway. Pathway maps of the Kyoto Encyclopedia of Genes and Genomes (KEGG) and maps generated from their gene classifications are available at KaPPA-View4 KEGG version (http://kpv.kazusa.or.jp/kpv4-kegg/). At present, gene co-expression data from the databases ATTED-II, COXPRESdb, CoP and MiBASE for human, mouse, rat, Arabidopsis, rice, tomato and other plants are available