Harmonic compensation using a synchronous machine with resonantfield circuits

This paper deals with a harmonic compensation method using a synchronous machine with resonant field circuits. Harmonics have become one of the major problems in power systems and a lot of methods of harmonic suppression have been studied. The authors have proposed a new method of harmonic suppression using a synchronous machine excited with the 6th harmonic current. This paper shows that armature inductances for the 5th or 7th harmonics decrease when the field circuits are connected to capacitors resonating at the 6th harmonic. The variations of armature impedances are explained theoretically by Park's equations. The optimal capacitances are selected so as to resonate with field inductances for the short-circuited armature. The experiments to suppress the 5th and 7th harmonics using the synchronous machine are successful     

CFD modeling of snowdrift around a building: An overview of models and evaluation of a new approach

The first part of this paper provides an overview of Computational Fluid Dynamics (CFD) modeling of snowdrift around a building by reviewing previous research including the authors’ in order to clarify its applicability and limitations. It is clarified that a quantitative validation study in particular by predicting snow depth distribution near a building is not enough, even though many models have been proposed. The latter part presents the results of CFD prediction of snowdrift around a cubic building model using a new approach of a snowdrift model based on experimental and numerical studies by the authors. The numerical results are compared with data obtained from detailed field measurements and previous CFD in order to confirm the accuracy of the new model. This new approach shows good correspondence with results obtained from field measurements and wind tunnel experiments in terms of not only snowdrift patterns but also quantitative distribution of snow depth.     

Comprehensive analysis of minimum grain size in pure aluminum using friction stir processing

A friction stir processing (FSP) technique has been developed for use with aluminum and magnesium alloys, with the goal of high-strain-rate processing. In this study, we treat the microstructures of aluminum samples, of three levels of purity, manipulating their grain sizes, making them finer, using FSP. Grain sizes decreased with an increase in the Zener-Hollomon parameter, at all purity levels. However, the recrystallized grain of FSP-ed ultra-high-purity (99.999%) aluminum was particularly large, compared to the grain sizes of lower-purity (99% and 99.99%) aluminum, when subjected to the same processing conditions. The grain size reached a certain minimum value at high-strain-rates of processing, which we report for each purity level herein.     

Enzymatic enrichment of arachidonic acid from Mortierella single-cell oil

An attempt was made to enrich arachidonic acid (AA) from Mortierella single-cell oil, which had an AA content of 25%. The first step involved the hydrolysis of the oil with Pseudomonas sp. lipase. A mixture of 2.5 g oil, 2.5 g water, and 4000 units (U) Pseudomonas lipase was incubated at 40°C for 40 h with stirring at 500 rpm. The hydrolysis was 90% complete after 40 h, and the resulting free fatty acids (FFA) were extracted with n-hexane (AA content, 25%; recovery of AA, 91%). The second step involved the selective esterification of the fatty acids with lauryl alcohol and Candida rugosa lipase. A mixture of 3.5 g fatty acids/lauryl alcohol (1:1, mol/mol), 1.5 g water, and 1000 U Candida lipase was incubated at 30°C for 16 h with stirring at 500 rpm. Under these conditions, 55% of the fatty acids were esterified, and the AA content in the FFA fraction was raised to 51% with a 92% yield. The long-chain saturated fatty acids in the FFA fraction were eliminated as urea adducts. This procedure raised the AA content to 63%. To further elevate the AA content, the fatty acids were esterified again in the same manner with Candida lipase. The repeated esterification raised the AA content to 75% with a recovery of 71% of its initial content.     

On an implicit stress-calculation algorithm for a multidimensional constitutive law using a skeleton curve

In this paper, we present an implicit stress-calculation algorithm for a multidimensional constitutive law using a one-dimensional skeleton curve and a hysteresis curve. To consider the hysteretic behavior of soils, one-dimension skeleton curves (e.g., the Hardin–Drnevich model, Ramberg–Osgood (RO) model, and general hyperbolic equation (GHE) model) are widely used. In a multidimensional analysis, there are several methods for extending a constitutive law using a skeleton curve into multiple dimensions. However, because these methods are suitable for an explicit integration stress-calculation scheme, a calculated stress does not satisfy the function of skeleton curve when a large incremental strain is imposed in one step. In this paper, to resolve this problem, a nonlinear stress–strain relation using a skeleton curve and an implicit stress-calculation algorithm is presented. In addition, we show an example of an application of the GHE/RO model to the proposed algorithm.     

Estimating reflection parameters from a single color image

This article proposes a method for estimating various parameters of a reflection model from a single color image of an object. We used an RGB charge-coupled device (CCD) camera for imaging and parameter estimation. We assumed the object surface is composed of an inhomogeneous dielectric material and used the Phong model to describe the surface's dichromatic reflection. This approach also generalizes to objects with smooth convex surfaces     

Synthesis of an AlN Polycrystalline Bulk Layer and Nanotubes by Using NH3 and Bi

A bulk layer of aluminum nitride (AlN) polycrystals was synthesized on a boron nitride crucible surface by heating Al chunks with 5 mol% of bismuth at 1273 K for 3 h under NH₃ gas flow. The fragments of the layer were characterized by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The platelet grains of AlN with a size of 0.1–1.0 μm and having preferred orientation of the c -axis perpendicular to the layer were formed at the crucible side. Nanotubes 6–15 μm long and about 20–100 nm thick grew on the gas phase side of the layer.     

Characterization of endogenous enzymes of milled rice and its application to rice cooking

The relationship between the activities of endogenous enzymes in milled rice and accumulation of chemical components in the rice grains during cooking was investigated. Maltose and soluble starch were optimally hydrolyzed around 60 °C by both crude extracts and purified α-glucosidases of milled rice. Gelatinization onset temperature of rice flour was determined to be 63 °C with DSC analysis under usual cooking condition. Hydrolytic activities on carbohydrates and proteolytic activities of milled rice were enhanced at pH 5 compared to pH 7 at the range of 4–80 °C. When rice was cooked at pH 5, glucose and amino acids highly accumulated with soaking for 16 h before heating. We propose a new method of cooking with prolonged soaking at acidic pH, which is effective for increasing the amounts of chemical components in cooked rice.     

Framework for Performance-Based Design of Building Structures

Abstract:   This article proposes a new framework for performance-based design (PBD) of building structures. This framework was proposed under the 3-year Japanese Government Comprehensive Research and Development Project on "Development of a New Engineering Framework for Building Structures" launched in the fiscal year of 1995. The primary objective of the project is to create a system in which the performance of buildings is clearly stated, and consumers, that is, occupants, are well informed of how their buildings will perform and how much it will cost to maintain their performance. The framework emphasizes the establishment of target performance, the performance evaluation, and the performance statement as the main three elements. It also stresses that an institutional framework and support systems need to be provided to enable PBD to be practiced efficiently. The implementation of the proposed framework is also expected to promote engineering innovation, progress in building engineering, and globalization. The new framework will also bring other benefits, such as improved design techniques, greater design flexibility, and international harmonization. It is also important for building structural performance to become one of the most important indexes for consumers to define a building's value. The Japanese building code was changed to the performance-based code, based in the clear and comprehensive manner proposed in this article. In the United States, "Vision 2000" ( SEAOC, 1995 ) was published, then many research activities were conducted simultaneously.     

Expression of IFN-inducible protein-10 in chronic hepatitis

Chemokines such as IFN-inducible protein-10 (IP-10) and JE/monocyte chemotactic protein-1 (MCP-1) are induced in the murine liver in a tissue-specific manner. We examined whether IP-10 and MCP-1 are pathologically involved in chronic hepatitis. Whereas the serum levels of IP-10 and MCP-1 in patients with chronic persistent hepatitis C were elevated compared with those in normal volunteers, both chemokine levels were further significantly higher in patients with the active form (chronic active hepatitis (CAH)). The elevated IP-10 level was not a general phenomenon of inflammation, because it was not seen in patients with rheumatoid arthritis, whereas MCP-1 levels were elevated to the same extent in both patient groups. Better responsiveness to IFN therapy in CAH was related to lesser grades of necroinflammatory activity and was predicted by the lower IP-10 and higher MCP-1 levels. IP-10 levels in patients cured by IFN therapy decreased to the levels in normal volunteers, while the MCP-1 levels only slightly decreased. Serum levels of both chemokines in patients who were not cured remained unchanged after IFN therapy. In situ hybridization analysis of CAH revealed that IP-10 mRNA was expressed mainly in hepatocytes around intralobular focal and periportal piecemeal necrosis, while some MCP-1 mRNA was expressed in some sinusoidal cells. These results suggested that IP-10 plays a specific role in the intralobular accumulation of mononuclear cells and/or the death of hepatocytes in chronic hepatitis.