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The electrical insulation structure of most power transformers is a combination of insulating oil and solid materials. One of the crucial problems we face in transformer operation is flow electrification, which occurs at a flowing oil/solid material interface. Thus, for the transformer insulation design, we need to clarify the flow electrification phenomena. In this paper, we measured the electric field strength in an oil/pressboard composite insulation system using an electro-optic method of the Kerr effect. We obtained the time variation of electric field distribution in both flowing uncharged and charged oil. It is notable that we could quantitatively clarify the electric field distortion in flowing charged oil by flow electrification. Furthermore, we measured the leakage current from divided electrodes and derived a charge density distribution along the flow direction. Finally, we quantitatively discussed the electric field distribution and the charge behavior from the measurement results. Index Terms--Charge behavior, flowing charged oil, oil/pressboard transformer model, Kerr effect, electric field measurement.

An insulating oil/pressboard (PB) composite insulation is generally utilized in oil-immersed power transformers. In such a transformer, charges accumulate at oil/PB interface which changes the electric field distribution depending on time and oil condition. In this paper, we report on directly measured dc electric field in oil/PB composite insulation system using the Kerr electro-optic field measurement technique. From measurement results, we propose a physical model for the charge behavior. We have calculated an electric field distribution using finite element method (FEM) based on the charge movement. We compared the results of measurements and calculations and confirmed that the proposed charge behavior model explains well the experimental results in the case of the polarity reversals as well. As a result, a significant validity of the charge behavior model was confirmed. Index Terms--Charge accumulation, polarity reversal, oil/pressboard, transformer model, Kerr effect, electric field measurement, FEM calculation.

It is important to investigate electrostatic charging phenomena in insulating oil / pressboard (PB) composite system in electrical insulation design of oil-immersed power transformers. Our research aim was to clarify the charge accumulation mechanism at the oil / PB interface under static and flowing oil. In this paper, we directly measured the time variation of the electric field in the insulation system using a Kerr electro-optic technique. Results show the time decaying characteristics of an electric field in oil by charge accumulation. The results are influenced by oil flow conditions. Based on the measurement results, we propose a theoretical model for charge accumulation to clarify the process quantitatively. In the model we took the oil volume contributing to the charge accumulation into account, and analyzed the charge behavior. Finally, we clarified the charge accumulation mechanism at the oil / PB interface under oil flow conditions both with and without charging. Index Terms--Charge accumulation mechanism, oil flow, charged oil, electric field measurement, Kerr effect, oil/pressboard composite system, streaming electrification.

This paper describes the semi-quantitative analysis of metal nanoparticle ink using laser-induced breakdown spectroscopy (LIBS). LIBS can be used to obtain information about the density and chemical composition of silver particles or copper particles, even ultrafine particles. Metal particles have been attracting much attention because of their increased use in new micro-nano technologies. In this work, LIBS was used as a fine metal particle measurement system for nanometallic materials used in printing. Good spectral peak resolutions were obtained when the Ag spectra were recorded at wavelengths of 328.068 nm and 338.289 nm and Cu spectra at 324.754 nm and 327.396 nm [ABSTRACT FROM AUTHOR]

In this paper, composition analysis using scanning electron microscopy/energy-dispersive X-ray spectroscopy analysis (SEM-EDX) and laser-induced breakdown spectroscopy (LIBS) for particulate matter in diesel exhaust is presented. Conventionally, scanning mobility particle sizer (SMPS) has been widely used to obtain particle size distribution of the suspended particles. However, real-time analysis of the composition of diesel particulate matter is difficult because of the small sized particles and rapidly exhausted. The particulates are less than a few micrometers in diameter. Real-time chemical analysis of the very small sized particles emitted from diesel fuels is facilitated with LIBS technique. [ABSTRACT FROM AUTHOR]

Abstract: A first empirical extraction of the transversity distributions for the u- and d-quarks has been done by Anselmino et al. based on the combined global analysis of the measured azimuthal asymmetries in semi-inclusive deep inelastic scatterings and those in processes. Although with large uncertainties, the determined transversity distributions already appear to reveal a remarkable qualitative difference with the corresponding longitudinally polarized distributions. We point out that this difference contains very important information on internal spin structure of the nucleon. [Copyright &y& Elsevier]

Abstract: It is known that some of the deeply-virtual-Compton-scattering observables, for instance, the beam-charge asymmetry in the hard electroproduction of real photons on the nucleon, are extremely sensitive to the magnitude of D-term appearing in the parameterization of the generalized parton distributions. We report a theoretical analysis of both the isoscalar and isovector parts of the nucleon D-term within the framework of the chiral quark soliton model, without recourse to the derivative expansion type approximation used in previous works. [Copyright &y& Elsevier]

Abstract: Very recently, a new measurement of the deuteron spin-dependent structure function was reported by the COMPASS group. A main change from the old SMC measurement is a considerable improvement of the statistical accuracy in the low x region . We point out that the new COMPASS data for as well as their QCD fits for ΔΣ and are all remarkably close to our theoretical predictions given several years ago based on the chiral quark soliton model. [Copyright &y& Elsevier]

Presents a study that investigated electrostatic charging phenomena in insulating oil/pressboard composite system in electrical insulation design of oil-immersed power transformers. Theoretical background; Methodology; Results and discussion.

Objective: Our aims were to compare several prolapse-reducing techniques during urodynamic evaluation and prospectively evaluate their usefulness in identifying the incidence of low urethral closure pressure in continent patients with massive prolapse.Study Design: This preoperative, prospective, repeated-measures urodynamic study evaluated the maximum urethral closure pressure with the use of four different techniques in 30 consecutive continent patients with grade 4 prolapse at all vaginal sites. Twenty patients with grade 0 prolapse served as the control group. All patients from the prolapse group underwent surgical treatment and were followed up clinically for a minimum of 1 year.Results: Use of the Scopette (Birchwood Laboratories, Eden Prairie, Minn.) reduction technique to reduce the prolapse in a linear orientation during multichannel urodynamics revealed a 56% incidence of low-pressure urethra and an overall genuine stress urinary incontinence of 83% in patients with massive pelvic organ prolapse but without clinical urinary incontinence.Conclusions: There may be an increased indication for sling urethropexy in patients with massive prolapse. [ABSTRACT FROM AUTHOR]

A response by M. Wakamatsu to a letter to the editor about his article "The role of the orbital angular momentum in the proton spin," that was published in the 2010 issue, is presented.