Standardization of New Sliver Probe for Cooling Power Test of Polymer Quenchant

Technical committee for Japanese industrial standard of heat treating oils has studied on the new method for testing cooling power of aqueous quenchants. This method employed the cooling curve test of a new sliver rod probe,which has a metal-sheathed thermocouple at its geometrical center. The experimental study has clarified that this probe has the higher sensitivity and excellent durability. In order to standardize this probe for cooling power test of aqueous quenchants, the repeatability and reproducibility of test results etc. have been studied. D.O.P. (Di-2-ethylthexyl Phthalate)was used as reference quenching fluid for initial calibration and for periodic calibration verification of the probe and system.In addition, 10% brine was used to check the response capability of the probe and system to the sudden change of temperature. These procedures are established according to the experimental investigation. This new test method is going to be built in the revised version of JIS K 2242 “Heat treating oils” as the cooling power test method for aqueous quenchants.     

Corona Current Control by Mesh Grid

Corona charging is widely used for charging dielectric surfaces. It is desirable to attain precise and uniform surface voltage in its application. A corona charging method using a mesh grid is described. It is found that the corona current control characteristics by mesh grid can be expressed by a nondimensional parameter?the corona current transmission rate. This parameter is obtained experimentally. The method of parameter application in dielectric surface charging is expressed by a differential equation. This technique is applied to charging amorphous selenium xerographic plates and to neutralizing the charges on a dielectric surface. It is found that the surface voltage obtained by charging with a mesh grid is far more uniform than that obtained by charging without a mesh grid.     

The distribution of T lymphocytes,B lymphocytes,and dendritic‐like cells of the anal tonsil in the laboratory shrew,Suncus murinus

We investigated the distribution of T lymphocytes, B lymphocytes, and S‐100 protein‐immunoreactive dendritic‐like in the anal tonsil of the laboratory shrew, Suncus murinus. In adult animals, T lymphocytes were located mainly at the periphery of the anal tonsil, especially around small blood vessels. B lymphocytes were located in the central and subepithelial region of the anal tonsil, which includes primary lymphoid follicles, and in which there are small numbers of scattered T lymphocytes. B and T lymphocytes were distributed over 72.7 and 27.3% of the tonsillar area, respectively. However, their areas of distribution were not clearly distinguished. The areas containing B lymphocytes were enriched in S‐100 protein antibody‐immunoreactive cells, which exhibited a dendritic shape. These S‐100‐positive cells appeared to be identical to the follicular dendritic cells (FDC) seen in the follicles of lymphoid organs. These results suggest that the anal tonsils constitute one of the gut‐associated lymphoid tissues (GALT), and that a function of the anal tonsil includes the capture of intruding antigens that would generate protective antibody responses. Microsc. Res. Tech., 2011. © 2010 Wiley‐Liss, Inc.     

Preparation of macroporous zirconia monoliths from ionic precursors via an epoxide-mediated sol-gel process accompanied by phase separation

Monolithic macroporous zirconia (ZrO₂) derived from ionic precursors has been successfully fabricated via the epoxide-mediated sol-gel route accompanied by phase separation in the presence of propylene oxide (PO) and poly(ethylene oxide) (PEO). The addition of PO used as an acid scavenger mediates the gelation, whereas PEO enhances the polymerization-induced phase separation. The appropriate choice of the starting compositions allows the production of a macroporous zirconia monolith with a porosity of 52.9% and a Brunauer–Emmett–Teller (BET) surface area of 171.9 m² · g⁻¹. The resultant dried gel is amorphous, whereas tetragonal ZrO₂ and monoclinic ZrO₂ are precipitated at 400 and 600 °C, respectively, without spoiling the macroporous morphology. After solvothermal treatment with an ethanol solution of ammonia, tetragonal ZrO₂ monoliths with smooth skeletons and well-defined mesopores can be obtained, and the BET surface area is enhanced to 583.8 m² · g⁻¹.     

Homogenization modeling of domain switching in ferroelectric materials

We presented a multiscale nonlinear finite element simulation to analyze domain switching behaviors in ferroelectric materials. We utilized an incremental form of fundamental constitutive law to consider changes in the material properties caused by domain switching. A multiscale nonlinear problem was formulated by employing the asymptotic homogenization theory based on the perturbation method and implemented using finite element analysis. The developed simulation was applied to barium titanate with a Perovskite-type tetragonal crystal structure. The 90° and 180° domain switching behaviors of a single crystal were computed for verification. The nonlinear behaviors of a bulk polycrystal with virtual microstructure were analyzed as a case study. The variation of the crystal orientation distribution in the polycrystalline microstructure was analyzed to reveal its influence on macroscopic hysteresis and butterfly curves.     

Numerical study for enhancement of laminar flow mixing using multiple confined jets in a micro-can combustor

To meet demands arising as a result of present trends towards miniaturization, an innovative design for promoting mixing enhancement in a miniature can combustor is investigated using an unstructured finite-volume technique. A multi-holed baffle plate is employed to create a ring of oxidizer jets surrounding a single fuel jet in parallel with the axis of the cylindrical chamber. The baffle plate is found to produce a dramatic improvement to the mixing performance when compared with simpler co-axial jet cases. Relatively small changes in geometry are found to have a major influence on mixing for laminar isothermal flow.