Numerical ball swaging analysis of head arm for hard disk drives

Ball swaging is a method of joining the head gimbal assembly (HGA) with the arm of an E-Block by plastically deforming part of the baseplate against the arm. However, the force of the plastic deformation causes deformation of the HGA, and can cause flying height, static attitude, and vibration of the HGA to vary. In this study, we performed an elasto-plastic large-deformation analysis for ball swaging. Using the experimental results, we verified the accuracy of the numerical results for ball swaging and determined the deformation mechanism and the effect of the ball swaging. From these results, we clarified that the baseplate is influenced by the arm deformation due to the asymmetric stress and the baseplate deformation is a superposition of the arm’s deformation on the baseplate’s own deformation.     

Natural convection heat transfer of water in a horizontal circular gap

An experimental study on the natural convection heat transfer on a horizontal downward facing heated surface in a water gap was carried out under atmospheric pressure conditions. A total of 700 experimental data points were correlated using Rayleigh versus Nusselt number in various forms, based on different independent variables. The effects of different characteristic lengths and film temperatures were discussed. The results show that the buoyancy force acts as a resistance force for natural convection heat transfer on a downward facing horizontal heated surface in a confined space. For the estimation of the natural convection heat transfer under the present conditions, empirical correlations in which Nusselt number is expressed as a function of the Rayleigh number, or both Rayleigh and Prandtl numbers, may be used. When it is accurately predicted, the Nusselt number is expressed as a function of the Rayleigh and Prandtl numbers, as well as the gap width-to-heated surface diameter ratio; and uses the temperature difference between the heated surface and the ambient fluid in the definition of Rayleigh number. The characteristic length is the gap size and the film temperature is the average fluid temperature.     

Rapid Determination of Iodine Value and Saponification Value of Fish Oils by Near-Infrared Spectroscopy

ABSTRACT: A rapid method for determining the iodine value (IV) and saponification value (SV) offish oils has been developed using near-infrared (NIR) spectroscopy. The partial least squares (PLS) calibration model was made based on a spectral range between 7560 and 9100 cm⁻¹ due to CH bond. The method was validated by comparing the IV and SV of a series of fish oils predicted by the PLS model to the values obtained by the titration methods of the Japan Oil Chemists' Society. The NIR-predicted IV and SV were completely consistent with chemically determined IV and SV. The NIR method showed higher accuracy and reproducibility than the titration method. It would be suitable for IV and SV determinations offish oils, as well as vegetable oils, and it takes only 2 min per sample.     

Suitability of TBA method for the evaluation of the oxidative effect of non-water-soluble and water-soluble rosemary extracts

The antioxidative effects of rosemary and grape-seed extracts spiked in human plasma were examined using the thiobarbituric acid (TBA) method. The TBA values of plasma spiked with reagents to generate reactive oxygen species, such as singlet oxygen ((1)O(2)), hydroxyl radicals ((·)OH), peroxynitrite (ONOO(-)), and superoxide anions (O(2)(·-)), were measured by a flow injection analysis method with fluorescence (FL) detection. TBA values obtained by the addition of 50 mg/mL of rosemary extracts for (1)O(2), (·)OH, ONOO(-), and O(2)(·-) increased to 964 ± 65%, 1063 ± 61%, 758 ± 78%, and 698 ± 41%, respectively (n = 3, P < 0.01), whereas the values with 1 mg/mL of grape-seed extracts or tocopherol decreased (40.2 - 66.3%). Furthermore, the antioxidative effects of rosemary extract in rat plasma, spiked with reagents to generate (·)OH, were examined by high-performance liquid chromatography with FL detection. No peak, other than TBA-malondialdehyde, could be detected using wavelengths of 532 (λ(ex)) and 553 nm (λ(em)).     

Evaluation on potential for assessing indoor formaldehyde using biosensor system based on swimming behavior of Japanese medaka (oryzias latipes)

In order to develop an early-warning biosensor system for predicting the impact on health of long-term and low-level exposure to indoor chemical compounds, e.g. volatile organic compounds (VOCs), we evaluated the potential for assessing indoor air quality using the biosensor system based on the swimming behavior of Japanese medaka (oryzias latipes) as an indicator of indoor air quality in the beginning. As a technology to dissolve chemical compounds into water efficiently, a micro bubble generator was introduced. The test chemical was formaldehyde which is a representative of chemical compounds existing indoors. The result of the measuring solubility of formaldehyde was that formaldehyde concentration in water was raised to 0.12 mg/L when 1.0 mg/m³ of formaldehyde in air was bubbled for approximately 44 h. The correlation between the 0.1 mg/L of formaldehyde in water, which is roughly equivalent to 0.83 mg/m³ of formaldehyde in air, and the swimming activities of medaka was investigated. The fish showed abnormal behavior compared to one under a control treatment, e.g. the body movement distance decreased and the duration time near the upper water column increased significantly. It was verified that it is possible to detect concentrations of formaldehyde of 0.83 mg/m³ in indoor air using this proposed biosensor system.     

A transient chaotic associative memory model with temporary stay function

When chaotic dynamics is imparted to the neurons that compose the associative memory model, they search for stored patterns in a pattern space chaotically. However, this model has the deficiency that judgment of whether the stored pattern has been recollected or not is difficult because its behavior is always chaotic. Because all dynamics of the chaotic neurons are chaotic, chaotic transition is repeated. The transient‐chaotic associative network (TCAN) that Lee proposed changes from the state of chaos to the state of stability (nonchaos) transiently. Additionally, it has fast recollection speed, and has large memory capacity. However, the states of TCAN do not change chaotically. Based on these results, this paper proposes a transient chaotic associative memory model with a temporary stay function (TCAMMwithTSF) which has two capabilities: one is fast speed as the states of the model converge to a stored pattern, like TCAN, and the other is the ability to search the stored pattern in a pattern space chaotically, like chaotic neural networks. Finally, the characteristics and usefulness of TCAMMwithTSF are verified by a simulation study. © 2011 Wiley Periodicals, Inc. Electr Eng Jpn, 175(2): 29–36, 2011; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.21077     

Selective determination of native fluorescent bioamines through precolumn derivatization and liquid chromatography using intramolecular fluorescence resonance energy transfer detection

In this paper, we introduce a novel approach for the highly selective and sensitive analysis of native fluorescent bioamines (indoleamines and catecholamines). This method is based on intramolecular fluorescence resonance energy transfer (FRET) detection in a liquid chromatography (LC) system following precolumn derivatization of the bioamines' amino groups. In this detection process, we monitored the FRET from the native fluorescent moieties (donor) to the derivatized fluorophore (acceptor). From a screening study involving 15 fluorescent reagents, we found that o-phthalaldehyde (OPA) generated the FRET most effectively. The OPA derivatives of the native fluorescent bioamines emitted OPA fluorescence (445 nm) through an intermolecular FRET process when they were excited at the excitation maximum wavelengths of the native fluorescent bioamines (280 nm). The generation of FRET was confirmed through comparison with the analysis of a nonfluorescent amine (isoleucine) performed using LC and a three-dimensional fluorescence detection system. We were able to separate the OPA derivatives of the indoleamines and catecholamines when performing LC on an ODS column. The detection limits (signal-to-noise ratio, 3) for the indoleamines and catecholamines, at a 20-muL injection volume, were 17-120 and 28-200 fmol, respectively. The sensitivity of the intramolecular FRET-forming derivatization method is higher than those of systems that take advantage of both native fluorescence detection (i.e., without derivatization) and the conventional detection of OPA derivatives. Furthermore, this method provides enough selectivity and sensitivity for the determination of the indoleamines present in the urine of healthy humans.     

基于DC磁场的磁畴扩大读出技术

MAMMOS(MagneticAMplifyingMagneto-OpticalSystem)是磁畴扩大读出技术之一。该技术是将记录层的微小磁畴扩大复印到读出层,可防止微小磁畴中的信号降低,实现高分辨率的读出。读出时的磁场采用DC磁场,具有利用更简易的系统即可读出的优点。记录层采用RE-rich(富含稀土)的GdFeCo(钆铁钴),读出时施加10ka/m的DC磁场,0.25μm的连续磁畴,可获得43dB的CNR。与CAD-MSR相比,最突出的是0.3μm以下的磁畴的CNR得到了极大的改善,有利于更微小磁畴的读出。