Correlation for countercurrent flow limitation in a PWR hot leg

Numerical simulations were done to evaluate countercurrent flow limitation (CCFL) characteristics in a pressurized water reactor (PWR) hot leg with the diameter of 750 mm by using a volume of fluid (VOF) method implemented in the CFD software, FLUENT6.3.26. The calculated CCFL characteristics agreed well with known values including the UPTF data at 1.5 MPa. Sensitivity analyses for system pressures up to 8 MPa showed that the calculated CCFL characteristics in the Wallis diagram were slightly mitigated from 0.1 MPa to 1.5 MPa with increasing system pressure, but they did not change from 1.5 MPa to 8MPa. Using the CCFLs calculated in this study and values measured under air–water and steam–water conditions, a CCFL correlation and its uncertainty were derived.     

An innovation management approach for renewable energy deployment—the case of solar photovoltaic (PV) technology

In the discussion of renewable energy deployment, one key concern is the various types of barriers that renewable energy needs to overcome before it can make its way into the mainstream. These barriers increasingly shift from the technical to the economic and institutional. The most general types of barriers are due to technological ‘lock-out’ or to carbon ‘lock-in’ [Unruh, G., 2000. Understanding carbon lock-in. Energy Policy 28(12), 817–830 (Elsevier)].These barriers necessitate the development of a strategic approach to deploy or introduce renewable energy technology. Existing energy policy has mostly relied upon financial subsidies, market-based instruments such as renewable portfolio standards, and production tax credits to stimulate the installation and use of equipment to generate electricity from renewable sources. These strategies target mostly system-level decisions of end users.The purpose of this paper is to present an innovation perspective on the renewable energy deployment process by introducing the innovation value-added chain (IVC) framework. The analytical objective of IVC is to evaluate the impact of a new innovation on the various stakeholders and players in the development and deployment processes. A deployment or innovation strategy that causes minimal disruption, enhances existing competencies, or expedites new learning by the players has a higher chance to succeed.We draw upon two sets of system integration costs data for grid-connected distributed photovoltaic (PV) systems in Japan and the United States and demonstrate conspicuously different dynamic learning behaviors. These two deployment models can be understood in terms of how the IVCs are organized and how PV system integration projects are performed in the field. In addition, IVC-based findings can inform the targeted application of conventional financial subsidies for learning investment not only at the PV system level, but also at the (localized) system integration level. This would involve other stakeholders, thus suggesting new energy policy space. We highlight some future research directions using the IVC framework.     

Multi‐gene phylogenetic analysis reveals that shochu‐fermenting Saccharomyces cerevisiae strains form a distinct sub‐clade of the Japanese sake cluster

Shochu is a traditional Japanese distilled spirit. The formation of the distinguishing flavour of shochu produced in individual distilleries is attributed to putative indigenous yeast strains. In this study, we performed the first (to our knowledge) phylogenetic classification of shochu strains based on nucleotide gene sequences. We performed phylogenetic classification of 21 putative indigenous shochu yeast strains isolated from 11 distilleries. All of these strains were shown or confirmed to be Saccharomyces cerevisiae, sharing species identification with 34 known S. cerevisiae strains (including commonly used shochu, sake, ale, whisky, bakery, bioethanol and laboratory yeast strains and clinical isolate) that were tested in parallel. Our analysis used five genes that reflect genome‐level phylogeny for the strain‐level classification. In a first step, we demonstrated that partial regions of the ZAP1, THI7, PXL1, YRR1 and GLG1 genes were sufficient to reproduce previous sub‐species classifications. In a second step, these five analysed regions from each of 25 strains (four commonly used shochu strains and the 21 putative indigenous shochu strains) were concatenated and used to generate a phylogenetic tree. Further analysis revealed that the putative indigenous shochu yeast strains form a monophyletic group that includes both the shochu yeasts and a subset of the sake group strains; this cluster is a sister group to other sake yeast strains, together comprising a sake‐shochu group. Differences among shochu strains were small, suggesting that it may be possible to correlate subtle phenotypic differences among shochu flavours with specific differences in genome sequences. Copyright © 2017 John Wiley & Sons, Ltd.     

Photocatalytic degradation of methylene blue by Au-deposited TiO<Subscript>2</Subscript> film under UV irradiation

A TiO₂ photocatalytic film was prepared by the sol–gel and dip-coating methods. Au-loaded TiO₂ photocatalytic films were produced by the photodeposition method. The photocatalytic activity of the films under UV irradiation was evaluated by measuring the degradation of absorbance for a methylene blue (MB) aqueous solution. Au particles deposited on the TiO₂ film improved the photocatalytic activity under the O₂ bubbling condition. On the other hand, under N₂ or Ar bubbling, the doubly reduced form of MB, leuco-methylene blue (LMB), was formed at the beginning of UV irradiation, and then both MB and LMB were decomposed gradually by the photocatalytic reaction. In this process, Au particles on the TiO₂ film behave as electron traps.     

Involvement of Ghrelin Dynamics in Stress-Induced Eating Disorder: Effects of Sex and Aging

Stress, a factor that affects appetite in our daily lives, enhances or suppresses appetite and changes palatability. However, so far, the mechanisms underlying the link between stress and eating have not been fully elucidated. Among the peripherally produced appetite-related peptides, ghrelin is the only orexigenic peptide, and abnormalities in the dynamics and reactivity of this peptide are involved in appetite abnormalities in various diseases and psychological states. This review presents an overview of the research results of studies evaluating the effects of various stresses on appetite. The first half of this review describes the relationship between appetite and stress, and the second half describes the relationship between the appetite-promoting peptide ghrelin and stress. The effects of sex differences and aging under stress on appetite are also described.     

A novel islanding protection system for photovoltaic inverters

It is very difficult to detect an islanding condition of a power distribution line with conventional voltage or frequency relays while the output power and the load power of utility interactive PV inverter units are in nearly balanced state in both active power and reactive power. This is because a sufficiently large voltage or frequency change cannot be expected at such a balanced state. Many studies have been reported so far to complement dead bands in combination of active and passive methods to prevent the islanding, but none of them has been successful. This paper presents the principle of a new active method called slip mode frequency shift (SMS). With this method the reactive power between the inverter and the load is made unbalanced intentionally to cause the frequency to shift as if it slips down a slide. The performance when the dead bands are eliminated effectively in the range of practical use has been examined through simulation and experiments.     

Formation of WSi-based ohmic contacts to n-type GaAs

An outcome of the indirect doping concept conceived recently in NiGe-based Ohmic contacts has led to the development of annealed WSi-based Ohmic contacts to n-type GaAs for the first time. It was concluded that simultaneous addition of a “direct doping element” of Si in WSi_2.7 and an “indirect doping element (M)” such as Au, Pd, Cu, or Ag, was essential. The M(5 nm)/WSi_2.7(20nm)/W(50 nm) contacts showed Ohmic behavior after annealing with the lowest contact resistances of 0.4 Ω mm (6×10⁻⁶ cm²). In addition, the WSi-based contacts with a small amount of Au showed good thermal stability at 400 °C after contact formation. Microstructural analysis of the WSi contacts with Au showed formation of β-AuGa and WSi₂ compounds, which indicates that the Ohmic behavior would be due to heavy doping of Si at the GaAs surface induced by Ga out-diffusion. The mechanism of Ohmic contact formation of the present contacts agreed very well with that of the NiGe-based Ohmic contacts.     

Potent stimulation of myofilament force and ATPase activity of skeletal muscle by eudistomin M, a novel Ca(++)-sensitizing agent from a Caribbean tunicate

In the course of our survey of biologically active compounds from natural sources, eudistomins were isolated from a Caribbean tunicate Eudistoma olivaceum. In the present experiments, eudistomin M (Eud-M, > 10(-5) M) caused a concentration-dependent increase in the contractile response of skinned fibers from guinea pig skeletal psoas muscles to Ca++. The superprecipitation and ATPase activity of myosin B from fast skeletal muscles of rabbit back and leg were potentiated by this compound (> 10(-5) M) in a concentration-dependent manner. In skinned fibers, superprecipitation and the ATPase activity of myosin B, Eud-M shifted the concentration-response curve for Ca++ to the upper direction. Ca(++)-, K(+)-EDTA- or Mg(++)-ATPase was not affected by Eud-M. This compound had no effect on the ATPase activity of actomyosin reconstituted from actin and myosin in the presence or absence of troponin. However, the ATPase activity of actin-myosin-troponin-tropomyosin reconstituted system was increased significantly by Eud-M. These results suggest that Eud-M increases the Ca++ sensitivity of the contractile apparatus in skeletal muscles at least partially mediated through troponin-tropomyosin system and thus enhances the ATPase activity of myosin B and the contractile force of myofilament.     

Effect of Porosity and Microstructure on the Strength of Si3N4: Designed Microstructure for High Strength, High Thermal Shock Resistance, and Facile Machining

The flexural strength of porous Si₃N₄ ceramics with a variety of microstructures and porosities were evaluated, and the effect of microstructure on the flexural strength was investigated to obtain machinable Si₃N₄ ceramics having both high strength and high thermal shock resistance. Porous Si₃N₄ having three types of microstructure, consisting of (1) only spherical grains, (2) combinations of spherical and columnar grains, and (3) only columnar β-grains connected randomly in three dimensions, were readied as specimens. Their mean pore diameters and porosities were 0.2 to 0.3 μm and 8% to 59%, respectively. The flexural strength of the porous Si3N4 (3) was much larger than that of the porous Si3N4 having the other microstructures, and the maximum flexural strength was 455 MPa at a porosity of 38.3%. The thermal shock resistance (ΔT), which was determined by a water quench test, of porous Si₃N₄ with such microstructure and a porosity of 50% was 980 K. All of the porous Si₃N₄ (3) was easily machined with cemented carbide drills.