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Surface Microstructure (surface + microstructure)
Selected AbstractsEffects of Heat Treatment on the Surface Microstructure and Mechanical Properties of MoSi2 -TiC0.7N0.3 CompositesJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 5 2002Yu-Ping Zeng MoSi2 -TiC0.7N0.3 composites were prepared by hot-pressing under vacuum, and MoSi2,TiC0.7N0.3 composites were heat-treated in air at various temperatures. SEM analysis showed that the surface microstructure of the MoSi2 -TiC0.7N0.3 composite changed because of the oxidation of MoSi2 and TiC0.7N0.3 and that many TiO2 whiskers appeared on the surfaces of the composites. Compared with the non-heat-treated MoSi2 -TiC0.7N0.3, the bending strength of the heat-treated MoSi2 -TiC0.7N0.3 was significantly improved. [source] Sintering Behavior and Surface Microstructure of PbO-Rich PbNi1/3Nb2/3O3,PbTiO3,PbZrO3 CeramicsJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 11 2001Masao Kondo The sintering behavior and surface microstructure of PbNi1/3Nb2/3O3,PbTiO3,PbZrO3 (PNiNb-PT-PZ) ceramics were investigated. The PNiNb-PT-PZ ceramics with the stoichiometric composition and the addition of excess lead oxide (PbO-rich ceramics) were sintered by liquid-phase sintering in accordance with the solution-reprecipitation mechanism at temperatures below the melting point of PbO. The temperature at which the liquid phase forms fell to near the eutectic point of the PbO,Nb2O5 and the PbO,TiO2 system (868°C) with the addition of 5 mol% PbO. As the calcination temperature influenced the sinterability of the stoichiometric PNiNb-PT-PZ ceramic, unreacted PbO was considered to be the source of the liquid phase in the sintering of the stoichiometric powder. The secondary phase was observed at the surface of PbO-rich ceramics and was suggested to be a liquid phase expelled from inside the ceramic. A sintering scheme of PNiNb-PT-PZ ceramics was proposed, and the high sinterability of PNiNb-PT-PZ ceramics was attributed to the low formation temperature of the liquid phase. [source] NEW APPLICATION OF NARROW BAND IMAGING FOR CHOLANGIOPANCREATOSCOPYDIGESTIVE ENDOSCOPY, Issue 2007Mitsuhiro Kida The usefulness of narrow band imaging (NBI), which is based on the principle that the depth of light penetration depends on its wavelength, has been accepted for evaluating malignant or benign lesions in the pharynx, the upper, and lower gastrointestine. The purpose of the present paper was to investigate NBI for diagnosing biliopancreatic disease. Using NBI it has become easy to detect the surface microstructure of biliary mucosa and subjacent vascular network of the bile duct, and inflammatory scarring stenosis is visualized as a whitish scar and multiple inflammatory red spots. However, bile duct cancer was detected as a stenosis with abnormal subjacent vessels and irregular surface. Concerning pancreatic duct, NBI has clearly shown vascular network and spreading of branch-type intraductal papillary mucinous neoplasm to the main pancreatic duct. In contrast, bile juice has been detected as red fluid and bleeding as black red. Therefore, it is important to flush the biliary system before observing with NBI. [source] Fractal Approach to Hierarchically Evolved Laser Processed CaP CoatingsADVANCED ENGINEERING MATERIALS, Issue 6 2010Anil Kumar Kurella This paper discusses a fractal approach to understand nature inspired laser surface engineered coatings. Via a laser surface engineering process a multi-scale CaTiO3 coating was synthesized on Ti alloy surface. At faster laser processing speeds star like CaTiO3 features evolved inside rings rich in calcium phosphate and TiO2. The porosity developed through the distribution of these particles results in a multi-scale distribution. Fractal analysis revealed that such laser processed surfaces had consistent fractal dimension over multiple length scales. This multi-scale and multi-phase surface microstructure contributed to enhanced biomimetic precipitation. [source] Frost formation on a bionic super-hydrophobic surface under natural convection conditionsHEAT TRANSFER - ASIAN RESEARCH (FORMERLY HEAT TRANSFER-JAPANESE RESEARCH), Issue 7 2008Yunjun Gou Abstract A bionic super-hydrophobic surface has a multiple micro-nano-binary structure (MNBS) similar to the lotus leaf surface microstructure. This kind of surface has a contact angle of water greater than 150° and a roll angle smaller than 5°. In this paper, the frost deposition phenomena on a bionic super-hydrophobic surface were observed. The surface has many micro bumps and its contact angle is 162°. The formation of water droplets, the droplet freezing process, the formation of initial frost crystals and the frost layer structure on a cold bionic super-hydrophobic surface under natural convection conditions were closely observed. The frost layer structure formed on the super-hydrophobic surface shows remarkable differences to that on a plain copper surface: the structure is weaker, looser, thin, and easily removed and most importantly, it is of a very special pattern, a pattern similar to a chrysanthemum, a frost layer structure that has not been reported before to the best of the present authors knowledge. The experimental results also show that a super-hydrophobic surface has a strong ability to restrain frost growth. The frost deposition on this bionic surface was delayed 55 minutes when compared with a plain copper surface under the conditions of a cold plate temperature of ,10.1°C, air temperature of 18.4°C, and relative humidity of 40%. A theoretical analysis was also presented to explain the observed phenomena. © 2008 Wiley Periodicals, Inc. Heat Trans Asian Res, 37(7): 412,420, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.20216 [source] Effects of Heat Treatment on the Surface Microstructure and Mechanical Properties of MoSi2 -TiC0.7N0.3 CompositesJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 5 2002Yu-Ping Zeng MoSi2 -TiC0.7N0.3 composites were prepared by hot-pressing under vacuum, and MoSi2,TiC0.7N0.3 composites were heat-treated in air at various temperatures. SEM analysis showed that the surface microstructure of the MoSi2 -TiC0.7N0.3 composite changed because of the oxidation of MoSi2 and TiC0.7N0.3 and that many TiO2 whiskers appeared on the surfaces of the composites. Compared with the non-heat-treated MoSi2 -TiC0.7N0.3, the bending strength of the heat-treated MoSi2 -TiC0.7N0.3 was significantly improved. [source] Sintering Behavior and Surface Microstructure of PbO-Rich PbNi1/3Nb2/3O3,PbTiO3,PbZrO3 CeramicsJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 11 2001Masao Kondo The sintering behavior and surface microstructure of PbNi1/3Nb2/3O3,PbTiO3,PbZrO3 (PNiNb-PT-PZ) ceramics were investigated. The PNiNb-PT-PZ ceramics with the stoichiometric composition and the addition of excess lead oxide (PbO-rich ceramics) were sintered by liquid-phase sintering in accordance with the solution-reprecipitation mechanism at temperatures below the melting point of PbO. The temperature at which the liquid phase forms fell to near the eutectic point of the PbO,Nb2O5 and the PbO,TiO2 system (868°C) with the addition of 5 mol% PbO. As the calcination temperature influenced the sinterability of the stoichiometric PNiNb-PT-PZ ceramic, unreacted PbO was considered to be the source of the liquid phase in the sintering of the stoichiometric powder. The secondary phase was observed at the surface of PbO-rich ceramics and was suggested to be a liquid phase expelled from inside the ceramic. A sintering scheme of PNiNb-PT-PZ ceramics was proposed, and the high sinterability of PNiNb-PT-PZ ceramics was attributed to the low formation temperature of the liquid phase. [source] Physicochemical Properties of Functional Surfaces in Pitchers of the Carnivorous Plant Nepenthes alata Blanco (Nepenthaceae)PLANT BIOLOGY, Issue 6 2006E. V. Gorb Abstract: Pitchers of the carnivorous plant Nepenthes alata are highly specialized organs adapted to attract, capture, and digest animals, mostly insects. They consist of several well distinguishable zones, differing in macro-morphology, surface microstructure, and functions. Since physicochemical properties of these surfaces may influence insect adhesion, we measured contact angles of non-polar (diiodomethane) and polar liquids (water and ethylene glycol) and estimated the free surface energy of 1) the lid, 2) the peristome, 3) the waxy surface of the slippery zone, and 4) the glandular surface of the digestive zone in N. alata pitchers. As a control, the external surface of the pitcher, as well as abaxial and adaxial surfaces of the leaf blade, was measured. Both leaf surfaces, both lid surfaces, and the external pitcher surface showed similar contact angles and had rather high values of surface free energy with relatively high dispersion component. These surfaces are considered to support strong adhesion forces based on the capillary interaction, and by this, to promote successful attachment of insects. The waxy surface is almost unwettable, has extremely low surface energy, and therefore, must essentially decrease insect adhesion. Both the peristome and glandular surfaces are wetted readily with both non-polar and polar liquids and have very high surface energy with a predominating polar component. These properties result in the preclusion of insect adhesion due to the hydrophilic lubricating film covering the surfaces. The obtained results support field observations and laboratory experiments of previous authors that demonstrated the possible role of different pitcher surfaces in insect trapping and retention. [source] Loss of cartilage structure, stiffness, and frictional properties in mice lacking PRG4ARTHRITIS & RHEUMATISM, Issue 6 2010Jeffrey M. Coles Objective To assess the role of the glycoprotein PRG4 in joint lubrication and chondroprotection by measuring friction, stiffness, surface topography, and subsurface histology of the hip joints of Prg4,/, and wild-type (WT) mice. Methods Friction and elastic modulus were measured in cartilage from the femoral heads of Prg4,/, and WT mice ages 2, 4, 10, and 16 weeks using atomic force microscopy, and the surface microstructure was imaged. Histologic sections of each femoral head were stained and graded. Results Histologic analysis of the joints of Prg4,/, mice showed an enlarged, fragmented surface layer of variable thickness with Safranin O,positive formations sometimes present, a roughened underlying articular cartilage surface, and a progressive loss of pericellular proteoglycans. Friction was significantly higher on cartilage of Prg4,/, mice at age 16 weeks, but statistically significant differences in friction were not detected at younger ages. The elastic modulus of the cartilage was similar between cartilage surfaces of Prg4,/, and WT mice at young ages, but cartilage of WT mice showed increasing stiffness with age, with significantly higher moduli than cartilage of Prg4,/, mice at older ages. Conclusion Deletion of the gene Prg4 results in significant structural and biomechanical changes in the articular cartilage with age, some of which are consistent with osteoarthritic degeneration. These findings suggest that PRG4 plays a significant role in preserving normal joint structure and function. [source] CFD Simulation of Liquid Film Flow on Inclined PlatesCHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 10 2004F. Gu Abstract A two-phase flow CFD model using the volume of fluid (VOF) method is presented for predicting the hydrodynamics of falling film flow on inclined plates, corresponding to the surface texture of structured packing. Using the proposed CFD model the influence of the solid surface microstructure, liquid properties and gas flow rate on the flow behavior was investigated. From the simulated results it was shown that under the condition of no gas flow the liquid flow patterns are dependent on the microstructure of the plates, and proper microstructuring of the solid surface will improve the formation of a continuous liquid film. It was also found that liquid properties, especially surface tension, play an important role in determining the thin-film pattern. However, there are very different liquid film patterns under the action of gas flow. Thinner liquid films break easily, but thicker liquid films can remain continuous even at higher gas flow rates, which demonstrates that all factors affecting the liquid film thickness will affect the liquid film patterns under conditions of counter-current two-phase flow. [source] | |||||||||||||