An enumeration scheme to generate constrained exact checkerboard patterns

Checkerboard patterns belong to a special class of 2-stage guillotine patterns that require less machine time to be cut. In this paper we propose an enumerative algorithm to generate exact constrained checkerboard patterns. At each node of the enumeration tree a constructive procedure is used to generate a feasible pattern. In addition, an upper bound on the objective function value is calculated to decide whether further branching from the node is worth. The algorithm was implemented and computational tests were performed. The test results indicate that the proposed scheme outperforms previous methods of the literature in terms of execution times.     

Use of pepsin for collagen extraction from the skin of bigeye snapper (Priacanthus tayenus)

Extraction and some properties of pepsin-solubilised collagens from the skin of bigeye snapper (Priacanthus tayenus) were investigated. Addition of bigeye snapper pepsin (BSP) at a level of 20 kUnits/g of defatted skin resulted in an increased content of collagen extracted from bigeye snapper skin. The yields of collagen from bigeye snapper skin extracted for 48 h with acid and with BSP were 5.31% and 18.74% (dry basis), respectively. With pre-swelling in acid for 24 h, collagen extracted with BSP at a level of 20 kUnits/g of defatted skin for 48 h had a yield of 19.79%, which was greater than that of collagen extracted using porcine pepsin at the same level (13.03%). The skin collagen was characterised to be type I with no disulfide bond. Electrophoretic study revealed slight differences in molecular weight between acid-solubilised collagen and all pepsin-solubilised collagens. The molecular weights of α1 and α2 chains in acid-solubilised collagen were estimated to be 120 and 112 kDa, respectively, whereas α1 and α2 chains of pepsin-solubilised collagens had molecular weights of 118 and 111 kDa, respectively. The result suggested that these pepsin-solubilised collagens might undergo partial cleavage in the telopeptide region by pepsin treatment. The maximum transition temperature (T_max) of acid-solubilised collagen was observed at 32.5 °C, which was slightly higher than that of pepsin-solubilised collagens (by about 1 °C). Generally, all collagens were highly solubilised in the pH range of 2–5 and sharply decreased at the neutral pH. No changes in solubility were observed in the presence of NaCl up to 3% (w/v) and the decrease was more pronounced with increasing NaCl concentration.     

Methane Oxidation on Perovskite-Type Ca(Mn1−xTix)O3−δ

X-ray photoelectron spectroscopy was performed to elucidate the catalytic activity of CH₄ oxidation on perovskite-type Ca(Mn_{1− x} Ti _x )O_3−δ synthesized at 1173 K in a flow of oxygen from a gel with citric acid and ethylene glycol. The Mn ion content decreases and the ratio of the Mn³⁺ ion in the Mn ion increases with increases in x . Ca(Mn_{1− x} Ti _x )O_3−δ has a high catalytic activity of CH₄ oxidation at x =0.4. These results indicate that the catalytic activity strongly depends on the Mn³⁺ ion content of the surface.     

An experimental study on aerodynamic sound generated from wake interaction of circular cylinder and airfoil with attack angle in tandem

In our previous study, the effects of the interval between the cylinder and the airfoil on the aerodynamic sound were investigated and compared with the cases of single circular and single airfoil. In this study, the effects of the attack angle of the airfoil located downstream on the characteristics of aerodynamic sound and the wake structure are investigated at a given interval between the cylinder and the airfoil. It is found that the sound pressure level of DFN and the peak frequency decrease with increasing attack angle of airfoil because of the diffusive wake structure due to the increased back pressure of circular cylinder, which is caused by the blocking effect of airfoil. It is shown that the sound sources are corresponded to the attack points of shedding vortex form the upstream circular cylinder to the downstream airfoil. We conclude that the pressure fluctuation at the airfoil surface effects on the sound pressure level, from the flow visualizations and the exploration test of sound source.     

Output power leveling of wind turbine generators using pitch angle control for all operating regions in wind farm

Effective utilization of renewable energies such as wind energy instead of fossil fuels is desirable. Wind energy is not constant and windmill output is proportional to the cube of the wind speed, which causes the generated power of wind turbine generators (WTGs) to fluctuate. In order to reduce the output power fluctuation of wind farms, this paper presents an output power leveling control strategy for a wind farm based on both the average wind farm output power and the standard deviation of the wind farm output power, a cooperative control strategy for WTGs, and pitch angle control using a generalized predictive controller (GPC) in all WTG operating regions. Simulation results using an actual detailed model for wind farm systems show the effectiveness of the proposed method. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 158(4): 31– 41, 2007; Published online in Wiley InterScience ( www.interscience. wiley.com ). DOI 10.1002/eej.20448     

Position control for a linear slider with twin linear drives

In this paper, position control of a linear slider with twin linear drives is considered. Recently, for high‐speed response, several linear motors have been used for linear slider systems. In such a linear slider, if the linear drives are controlled individually, their position responses may undergo vibrational disturbance by interaction with the output of the motors. To control this vibration, this paper presents a dynamic model of a linear slider system which consists of two motion systems decoupled by coordinate transformation, and proposes a feedback controller which is designed for these two decoupled systems. The effectiveness of the proposed method is confirmed by experiments. © 2004 Wiley Periodicals, Inc. Electr Eng Jpn, 147(4): 68–76, 2004; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10291     

Roughness of amorphous/crystalline interface in pre-amorphization implantation: Molecular dynamic simulation and modeling

Pre-amorphization implantation has been applied as a shallow junction technology. Roughness at amorphous/crystalline (a/c) interface should be controlled to improve junction characteristics. To understand and model a/c interface roughness, molecular dynamic method is applied in simulating pre-amorphization implantation. A method to reproduce roughness at a/c interface by molecular dynamic simulation is presented. A model of interface roughness is presented. Si and Ge implantation from 2-20 keV at a dose of 1 × 10¹⁵ cm⁻² is simulated. The depth of a/c interface is reproduced. Experimental results of a/c interface roughness are successfully simulated. The interface roughness is well reproduced and interpreted by the model presented.     

Lightning occurrence data observed with lightning location systems of electric power companies in Japan: 2009–2013

Nine electric power companies in Japan have been collecting lightning data with lightning location systems. Five years of the lightning data (2009–2013) are summarized and analyzed in this paper. The recent annual number of lightning flashes of which the current is more than 10 kA in Japan is around 1 million. The variations of lightning occurrence characteristics by areas, seasons, and so on, are clarified. Meteorological conditions that may affect lightning occurrence are also discussed. Furthermore, we show that there is a clear correlation between the number of lightning strikes and the outage rate of transmission lines. © 2016 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Structural Analysis of the Complex between Penta-EF-Hand ALG-2 Protein and Sec31A Peptide Reveals a Novel Target Recognition Mechanism of ALG-2

ALG-2, a 22-kDa penta-EF-hand protein, is involved in cell death, signal transduction, membrane trafficking, etc., by interacting with various proteins in mammalian cells in a Ca²⁺-dependent manner. Most known ALG-2-interacting proteins contain proline-rich regions in which either PPYPXnYP (type 1 motif) or PXPGF (type 2 motif) is commonly found. Previous X-ray crystal structural analysis of the complex between ALG-2 and an ALIX peptide revealed that the peptide binds to the two hydrophobic pockets. In the present study, we resolved the crystal structure of the complex between ALG-2 and a peptide of Sec31A (outer shell component of coat complex II, COPII; containing the type 2 motif) and found that the peptide binds to the third hydrophobic pocket (Pocket 3). While amino acid substitution of Phe⁸⁵, a Pocket 3 residue, with Ala abrogated the interaction with Sec31A, it did not affect the interaction with ALIX. On the other hand, amino acid substitution of Tyr¹⁸⁰, a Pocket 1 residue, with Ala caused loss of binding to ALIX, but maintained binding to Sec31A. We conclude that ALG-2 recognizes two types of motifs at different hydrophobic surfaces. Furthermore, based on the results of serial mutational analysis of the ALG-2-binding sites in Sec31A, the type 2 motif was newly defined.     

Acetylation of loofa (Luffa cylindrica) sponge as immobilization carrier for bioprocesses involving cellulase

The feasibility of using loofa sponge for immobilization of cellulase-producing microorganisms was investigated by acetylating loofa sponge. Acetylation was achieved by autoclaving process of loofa sponge immersed in acetic anhydride at various temperatures for various times. The degree of acetylation, as inferred by the weight percentage gain (WPG), was enhanced by increasing both temperature and the duration of acetylation. The acetylation of a piece of loofa sponge in an autoclave at 120 degrees C for 20 min resulted in a WPG of about 8%, which was sufficient to protect the loofa sponge against cellulose degradation. The acetylated loofa sponge prepared under this condition was not decomposed by commercial cellulase and its structure was maintained for more than 720 h during repeated-batch treatments with commercial cellulase. A flocculating yeast (Saccharomyces cerevisiae IR-2) and a fungus (Trichoderma reesei QM9414) were successfully immobilized in the acetylated loofa sponge. In each case, the percentage of immobilized cells was as high as that obtained using nonacetylated loofa sponge. Acetylation had no adverse effects on cell growth and immobilization of T. reesei QM9414, as well as on cell growth and ethanol production by S. cerevisiae IR-2. T. reesei QM9414 immobilized on an acetylated loofa sponge was successfully used for repeated-batch cellulase production from commercial cellulose powder. Although the acetylated loofa sponge showed a slight weight loss, it was not disintegrated by activated sludge. The results obtained in this study showed that acetylated loofa sponge is suitable as an immobilization carrier for bioprocesses involving cellulase.