Internal moisture evolution in timbers exposed to ambient conditions following kiln drying

This study aimed to investigate the changes of internal moisture content distribution within hem-fir timbers after kiln drying while exposed to two different local outdoors seasonal conditions. Timbers were dried to three different target moisture contents (12, 17, and 22 %) and thereafter, they were conditioned outdoors in two diverse seasonal coastal environments, namely, cold-wet wintertime and warm-dry summertime. Moisture contents at quarter-point and the center in depth were continuously monitored for a period of 3 weeks. The results showed that no significant moisture content reductions took place during the cold-wet season equalization, while moisture content differences were regularly reduced regardless of seasonal conditions. In addition, below 2.5 % differential moisture content, moisture movement between at quarter-point and the center slowed down regardless of seasonal condition or current moisture content level. At high drying target moisture content of 22 %, moisture content values both at quarter-point and the center remained constant after 2 weeks at moisture content difference value of 2.5 %, and no further drying or no further moisture content equalization were observed after that point.     

Relationship between microstructure of plasma-sprayed 8YZ coatings and thermal fatigue life of thermal barrier coatings

Microstructure of plasma-sprayed yttria-stabilized zirconia coatings (8YZ) was characterized by the measurement of surface roughness, hardness, and pore size distribution and was correlated with thermal fatigue life. It was confirmed that the coatings which had greater roughness tended to show both lower hardness and higher porosity. Furthermore, such coatings were found to have a longer thermal fatigue life. We propose that measurement of the roughness of 8YZ coatings is useful as a non-destructive evaluation method for predicting thermal fatigue life.     

Effect of Mn content on physical properties of CeOx–MnOy support and BaO–CeOx–MnOy catalysts for direct NO decomposition

A series of manganese–cerium mixed oxides were prepared by a glycothermal method, and the NO decomposition activities of the Ba-loaded Ce–Mn oxides were examined. Among the catalysts examined, the highest NO conversion was obtained on the BaO/Ce–Mn oxide catalyst with a Mn/(Ce+Mn) ratio of 0.25. The X-ray diffraction and Raman analyses indicated the formation of Ce–Mn oxide solid solutions with a cubic fluorite structure. The electron spin resonance analysis indicated the presence of paramagnetic Mn²⁺ species in the composite catalysts. Incorporation of Mn²⁺ in the fluorite structure of CeO₂ causes an increase in the concentration of oxygen vacancies, which play an important role in the NO decomposition activity of the catalysts. The catalysts were also characterized by X-ray photoelectron spectroscopy and temperature-programmed reduction techniques. Based on the results obtained, the relationship between the physical properties of the catalysts and their NO decomposition activities was discussed.     

A study on spot distortion for an in‐line self‐converging system for color CRTs

Abstract— The spot distortion at the screen periphery of an in‐line self‐converging CRT is formulated by considering four factors; (a) oblique incidence of the beam at the screen periphery, (b) increased path length of the beam, (c) beam compression due to the deflection, and (d) the astigmatism due to the deflection field. The analytic spot size calculated with the formulas agrees well with measurement, though the effects of a particular gun system, spherical aberration, and space‐charge repulsion are not taken into consideration in the formulas while assuming an ideal deflection field. The analytic formulas enable easy evaluation of spot distortion at the screen periphery because they give an intuitive understanding of beam behavior in the in‐line self‐converging system. In addition to the derivation of the formulas, “transposed scanning” is analyzed with the use of the formulas for one of the ways to optimize the spot distortion at the screen periphery.     

Preparation and Characterization of Hybrid Chitosan/Acrylic Resin Emulsions and Their Films

Summary: Solutions containing chitosan of different molecular weights and several acidic monomers were prepared under various aging conditions. Hybrid chitosan/acrylic resin emulsions were prepared from these solutions by emulsion polymerization. The viscosities of the hybrid chitosan/acrylic resin emulsions were influenced significantly by the molecular weight of chitosan, the acidic monomer used, and the aging conditions. DSC and FT‐IR spectroscopy of the hybrid chitosan/acrylic resin films indicated that chitosan was well distributed in the films. The water absorption and formaldehyde adsorption abilities of the acrylic resin films prepared with chitosan were higher than the corresponding films prepared without chitosan, and they increased with increasing molecular weight of the chitosan. The morphology of these films, studied by TEM, revealed that the distribution of chitosan in the hybrid chitosan/acrylic resin emulsion was dependent on the molecular weight of chitosan, the acidic monomer used, and the aging conditions.

Chitosan salts with acrylic acid (R = ? CH?CH₂), methacrylic acid (R = ? C(CH₃)?CH₂) and itaconic acid (R = ? CH₂(COOH)C?CH₂).     

Thermal Behavior of Nitrocellulose with Inorganic Salts and their Mechanistic Action

In this study, we investigated the effects of inorganic salts on the stability of NC and its reaction mechanism. Under isothermal conditions at 120 °C in an O₂ atmosphere, the induction time period for NC heat release was prolonged in the presence of Li₂CO₃, Na₂CO₃, CaCO₃, Mg(OH)₂, Ca(OH)₂, and MgO, all of which produce alkaline saturated solutions with a pH value of 10–12. In addition, the induction time period depended on this pH value. This suggests that these salts stabilized NC by neutralizing acids that would otherwise accelerate the hydrolysis of the O‐NO₂ bond. However, Sr(OH)₂ ⋅ 8H₂O and K₂CO₃, which produce strongly alkaline saturated solutions with pH>13, decreased the induction time period. It is possible that these strong bases caused alkaline decomposition of NC. In addition, for Sr(OH)₂ ⋅ 8H₂O, the released water of crystallization appeared to be related to NC destabilization. SrCO₃, NaHCO₃, K₂SO₄, CaSO₄, ZnSO₄, NaCl, CaCl₂, AgCl, and NaNO₂, which produce near‐neutral saturated solutions, slightly decreased the NC induction time period. The NC induction time period with these salts depended upon the solubility of the added salt. This may indicate that in the presence of these inorganic salts, the boiling point of water is increased, which reduces the vaporization of water from NC and thus accelerates the hydrolysis of NC.     

Development of Low Power Cryogenic Readout Integrated Circuits Using Fully-Depleted-Silicon-on-Insulator CMOS Technology for Far-Infrared Image Sensors

We are developing low power cryogenic readout integrated circuits (ROICs) for large format far-infrared image sensors using fully-depleted-silicon-on-insulator (FD-SOI) CMOS technology. We have evaluated the characteristics of MOS FETs fabricated by the FD-SOI CMOS technology and have found that both p-ch and n-ch FETs show good static performance below the liquid helium temperature, where n-ch FETs fabricated by conventional bulk-CMOS technology usually suffer from anomalous behaviors such as kink and hysteresis. We have also designed and fabricated an operational amplifier (OP-AMP) and have successfully demonstrated that the OP-AMP works at the liquid helium temperature with an open loop gain of 7000 and a power consumption of 1.3 μW. The noise is dominated by mainly 1/f and has a value of at?1?Hz.