PVDF actuator for high‐frequency fatigue test of thin‐film metals

This paper suggests a poly(vinylidene fluoride) (PVDF) piezoelectric diaphragm actuator used in a novel fatigue test method for thin metal films. A thin‐film metal specimen is stamped on top of the actuator using a stamping epoxy. As the actuator vibrates, the stress in the specimen increases until it fails under fatigue. A finite element model of the actuator is built, and its vibration amplitude is confirmed to be in a good agreement with experiment. Then, a model of the specimen is added to this model to simulate the vibration of the specimen for fatigue test. Stress analysis of the specimen at a driving voltage of 200 V_0−p confirms that this actuator can increase the stress in the specimen to near 1 GPa, which is high enough for the fatigue test of metals such as titanium. In the experiment, a thin‐film titanium specimen is stamped on top of the actuator which is then vibrated. The stress in the fatigue gauge on thin‐film specimen increased until the specimen failed under fatigue. This shows that the proposed PVDF actuator is suitable for the fatigue test of thin‐film metals such as titanium. © 2012 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Effect of catch cup geometry on 3D boundary layer flow over the wafer surface in a spin coating

Recently, development of high technology has been required for the formation of thin uniform film in manufacturing processes of semiconductor as the semiconductor instruments become more sophisticated. Spin coating is usually used for spreading photoresist on a wafer surface. However, since rotating speed of the disk is very high in spin coating, the dropped photoresist scarers outward and reattaches on the film surface. A catch cup is set up outside the wafer in spin coating, and scattered photoresist mist is removed from the wafer edge by the exhaust flow generated at the gap between the wafer edge and the catch cup. In the dry process of a spin coating, it is a serious concern that the film thickness increases near the wafer edge in the case of low rotating speed. The purpose of this study is to make clear the effect of the catch cup geometry on the 3D boundary layer flow over the wafer surface and the drying rate of liquid film.     

Controlled reduction of Cu to Cu with an N,O-type chelate under hydrothermal conditions to produce Cu2O nanoparticles

N,O-type organic chelates reduced coordinated Cu²⁺ ions under hydrothermal reaction conditions to produce Cu₂O/CuO nanoparticles. Chelates in which the N and O atoms are closely spaced produced smaller amounts of CuO nanoparticles, indicating their higher ability to reduce Cu²⁺ ions to Cu⁺ ions. [Cu(Gly)₂]² with the shortest ligand chain length produced only Cu₂O nanoparticles and, therefore, can be used as a single molecule precursor for the synthesis of Cu₂O nanoparticles.     

Facile purification of tocopherols from soybean oil deodorizer distillate in high yield using lipase

Tocopherols have been purified from deodorizer distillate produced in the final deodorization step of vegetable oil refining by a process including molecular distillation. Deodorizer distillate contains mainly tocopherols, sterols, and free fatty acids (FFA); the presence of sterols hinders tocopherol purification in good yield. We found that Candida rugosa lipase recognized sterols as substrates but not tocopherols, and that esterification of sterols with FFA could be effected with negligible influence of water content. Enzymatic esterification of sterols with FFA was thus used as a step in tocopherol purification. High boiling point substances including steryl esters were removed from soybean oil deodorizer distillate by distillation, and the resulting distillate (soybean oil deodorizer distillate tocopherol concentrate; SODDTC) was used as a starting material for tocopherol purification. Several factors affecting esterification of sterols were investigated, and the reaction conditions were determined as follows: A mixture of SODDTC and water (4∶1, w/w) was stirred at 35°C for 24 h with 200 U of Candida lipase per 1 g of the reaction mixture. Under these conditions, approximately 80% of sterols was esterified, but tocopherols were not esterified. After the reaction, tocopherols and FFA were recovered as a distillate by molecular distillation of the oil layer. To enhance further removal of the remaining sterols, the lipase-catalyzed reaction was repeated on the distillate under the same reaction conditions. As a result, more than 95% of the sterols was esterified in total. The resulting reaction mixture was fractionated to four distillates and one residue. The main distillate fraction contained 65 wt% tocopherols with low contents of FFA and sterols. In addition, the residue fraction contained high-purity steryl esters. Because the process presented in this study includes only organic solvent-free enzymatic reaction and molecular distillation, it is feasible as a new industrial purification method of tocopherols. This work was presented at the Biocatalysis symposium in April 2000, held at the 91st Annual Meeting and Expo of the American Oil Chemists Society, San Diego, CA.     

Development and evaluation of a certificate validation system in mobile environments

We have developed a public key certificate validation system considering the restrictions peculiar to the mobile environment, such as processing the speed and memory capacity of a cellular‐phone terminal, and the network transmission speed. In this paper we derive a theoretical formula showing the performance of a validity check of the public key certificate of the conventional system and of the proposed system, and compare and examine a theoretical value in a mobile environment. Moreover, we evaluate the actual measurement that uses the server and cellular‐phone terminal that we developed. We show that our proposed system based on the certificate validation server (CVS) system is better than the conventional system from the viewpoint of processing speed and transmission speed. Copyright © 2007 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Comparative Effects of Acetylated and Unmodified High‐amylose Maize Starch in Rats

Acetylated, propionylated or butyrylated starches raise the large bowel pools of these short chain fatty acids (SCFA) in rats but their resistant starch (RS) content in vivo is unknown. This content was determined for acetylated starch (Starch A, DS = 0.18) in colectomised rats and compared to a standard maize (control) or high‐amylose (HAMS) maize starch. Digestibilities were 99.8% (control), 47.5% (Starch A) and 58% (HAMS). The effects of Starch A and HAMS were compared also in intact rats, that were fed a fibre‐free diet in which either 200 g/kg of HAMS or 100, 200 or 300 g of Starch A/kg was substituted for the standard maize starch. Caecal SCFA pools were larger in rats fed either RS with the greatest increase being in acetate in rats fed Starch A. Other acids (succinate and formate) appeared with increasing incorporation of RS. However, when the experiment was performed with a commercial diet, feeding Starch A or HAMS did not lead to any great increase in these other acids but SCFA pools expanded. The greatest increase in acetate was in rats fed Starch A. This suggests that other factors were necessary for optimal RS fermentation but not for release of acetate from Starch A. Comparison of the effects of Starch A and HAMS on SCFA suggests that the former was at least 100% more effective than HAMS at equivalent dietary intakes, despite similarities in RS content. Incubation of Starch A with caecal bacterial enzymes confirmed that release of acetate was relatively slow, indicating a capacity of this modified starch for sustained SCFA delivery in vivo.     

Studies on analysis of terpene resin in imported chewing gums

We have developed an analytical method for terpene resins in chewing gum. The fraction including terpene resins was prepared by means of hexane extraction and two silica gel column chromatography treatments (hexane and ethyl acetate) from chewing gum. The terpene resin fraction was analyzed with LC/MS and IR. The terpene resins are mixtures of polymeric pinene and/or limonene, which have a monomer molecular weight of 136. The MS spectrum of the terpene resin peak on the LC/MS total ion chromatogram showed protonated molecular ion (M + H)+ peaks at intervals of m/z 136, characteristic of a complex mixture of polyterpenes. IR spectroscopy is a suitable technique to identify the terpene resin type, ie., pinene or limonene. When the method was applied to imported chewing gum sold in Japan, terpene resins were clearly detected.     

The viscoelastic behavior of short-fiber composite materials

This article examines the viscoelastic behavior of unidirectional short-fiber composites. Each fiber is approximated by an ellipsoidal elastic inclusion embedded in a viscoelastic matrix. The static correspondence principle which relates the viscoelastic problem to the elastic problem is applied to the modified expression of the effective elastic moduli of short-fiber composites originally derived by the authors. Numerical examples for various fiber aspect ratios are shown based upon the collocation approximation method. Comparisons of the result with the self-consistent method are also presented.     

Purification of steryl esters from soybean oil deodorizer distillate

Soybean oil deodorizer distillate (SODD) contains steryl esters in addition to tocopherols and sterols. Tocopherols and sterols have been industrially purified from SODD but no purification process for steryl esters has been developed. SODD was efficiently separated to low b.p. substances (including tocopherols and sterols) and high b.p. substances (including 11.2 wt% DAG, 32.1 wt% TAG, and 45.4 wt% steryl esters) by molecular distillation. The high b.p. fraction is referred to as soybean oil deodorizer distillate steryl ester concentrate (SODDSEC). We attempted to purify steryl esters after a lipase-catalyzed hydrolysis of acylglycerols in SODDSEC. Screening of industrially available lipases indicated that Candida rugosa lipase was most effective. Based on the study of several factors affecting hydrolysis, the reaction conditions were determined as follows: ratio of SODDSEC/water, 1∶1 (w/w); lipase amount, 15 U/g reaction mixture; temperature, 30°C. When SODDSEC was agitated for 24 h under these conditions, acylglycerols were almost completely hydrolyzed and the content of steryl esters did not change. However, study with a mixture of steryl oleate/trilinolein (1∶1, w/w) indicated that about 20% of constituent FA in steryl esters were exchanged with constituent FA in acylglycerols. Steryl esters in the oil layer obtained by the SODDSEC treatment with lipase were successfully purified by molecular distillation (purity, 97.3%; recovery, 87.7%).