534 research outputs found

    Refrigerant Characteristics of R-Al and R-Si Amorphous Alloys((A)Amorphous Alloys)

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    R-Al and R-Si amorphous ribbon and powder samples were prepared by melt-quenching and mechanical grinding, respectively, in order to investigate the refrigerant characteristics. The magnetic transition temperature is selected without difficulty because the alloy composition in the amorphous state is not restricted by the stoichiometric composition. The magnetic entropy change of Dy-Al and R-Si amorphous alloys shows a broad maximum around the transition temperature, which is advantageous for a wide temperature span of refrigeration. The softening of those amorphous alloys below the crystallization temperature is useful for the purpose of static consolidation. The Debye temperature is increased by addition of B

    Nonlinear steering control under input magnitude and rate constraints with exponential convergence

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    A ship steering control is designed for a nonlinear maneuvering model whose rudder manipulation is constrained in both magnitude and rate. In our method, the tracking problem of the target heading angle with input constraints is converted into the tracking problem for a strict-feedback system without any input constraints. To derive this system, hyperbolic tangent (tanh\tanh) function and auxiliary variables are introduced to deal with the input constraints. Furthermore, using the feature of the derivative of tanh\tanh function, auxiliary systems are successfully derived in the strict-feedback form. The backstepping method is utilized to construct the feedback control law for the resulting cascade system. The proposed steering control is verified in numerical experiments, and the result shows that the tracking of the target heading angle is successful using the proposed control law.Comment: 12 pages, 6 figures, a preprint submitted to the Journal of Marine Science and Technolog

    Effect of Paracoccus sp. and their Genetically Modified on Skin Coloration of Red Sea Bream

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    Astaxanthin (Asx) content in the skin of red sea bream was observed in a feeding trial with two Asx sources: marine bacteria (Paracoccus sp.) and Asx concentrated marine bacteria modified genetically (GM marine bacteria). Four semi purified diets were prepared and contained two levels of marine bacteria (15 and 30 mg Asx/kg), 30 mg Asx/kg of GM marine bacteria and control diet without additional Asx. The diets were fed to fourteen fish of red sea bream (initial weight 128.5 g) which were randomly distributed in each 60-l glass tank. Asx content in the skin of fish fed on non-GM marine bacteria diets were higher than that of fish fed on GM marine bacteria.  Additionally, Asx accumulation in the skin of fish fed on diet of non-GM marine bacteria containing 15 mg Asx/kg diet was higher than those fish fed on diet supplemented with 30 mg Asx/kg of GM marine bacteria. The results showed that by adding the supplement of Asx derived from marine bacteria (Paracoccus sp.) to the red sea bream diets might enhance the skin coloration of red sea bream and the other carotenoids contained in marine bacteria might also enhance the coloration

    Octopamine regulates social behaviors between genetically unrelated ant queens.

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    In different tasks involving action perception, performance has been found to be facilitated when the presented stimuli were produced by the participants themselves rather than by another participant. These results suggest that the same mental representations are accessed during both production and perception. However, with regard to spoken word perception, evidence also suggests that listeners’ representations for speech reflect the input from their surrounding linguistic community rather than their own idiosyncratic productions. Furthermore, speech perception is heavily influenced by indexical cues that may lead listeners to frame their interpretations of incoming speech signals with regard to speaker identity. In order to determine whether word recognition evinces similar self-advantages as found in action perception, it was necessary to eliminate indexical cues from the speech signal. We therefore asked participants to identify noise-vocoded versions of Dutch words that were based on either their own recordings or those of a statistically average speaker. The majority of participants were more accurate for the average speaker than for themselves, even after taking into account differences in intelligibility. These results suggest that the speech representations accessed during perception of noise-vocoded speech are more reflective of the input of the speech community, and hence that speech perception is not necessarily based on representations of one’s own speech

    Effects of dissolved oxygen and pH on nitrous oxide production rates in autotrophic partial nitrification granules

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    The effects of dissolved oxygen (DO) and pH on nitrous oxide (N2O) production rates and pathways in autotrophic partial nitrification (PN) granules were investigated at the granular level. N2O was primarily produced by betaproteobacterial ammonia-oxidizing bacteria, mainly Nitrosomonas europaea, in the oxic surface layer (<200 μm) of the autotrophic PN granules. N2O production increased with increasing bulk DO concentration owing to activation of the ammonia (i.e., hydroxylamine) oxidation in this layer. The highest N2O emissions were observed at pH 7.5, although the ammonia oxidation rate was unchanged between pH 6.5 and 8.5. Overall, the results of this study suggest that in situ analyses of PN granules are essential to gaining insight into N2O emission mechanisms in a granule

    Repetitive control of Hamiltonian systems based on variational symmetry

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    This paper is concerned with repetitive control of Hamiltonian systems, which is based on iterative learning control utilizing the variational symmetry of those systems. Variational symmetry allows us to obtain an algorithm to solve a certain class of optimal control problems in a repetitive control framework. Therefore, the proposed method can deal with not only trajectory tracking control problems but also optimal trajectory generation problems, never before considered in a repetitive control framework. A convergence analysis of this algorithm is also discussed. Furthermore, some numerical simulations demonstrate the effectiveness of the proposed method

    The Effect of Planar Sinks on the Interstitial Loop Growth under High Temperature Neutron Irradiation

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    The role of planar sinks such as surfaces and grain boundaries for the defect structure developments was studied in fission neutron irradiated Ni and Ni alloys of 2 at% Si, Cu, Ge and Sn to the dose of 4x10^n/m^2 (>1MeV) at 573 K by comparison between thin foil irradiation and bulk irradiation. The number density of interstitial loops increases and then decreases with the increase of distance from planar sinks. Observed defect structure developments were interpreted in terms of the variation of point defect concentration with the change of sink efficiency. The necessity of the introduction of cascade localization induced bias effect is emphasized

    Dimethyl sulfoxide-respiring bacteria in Suribati Ike, a hypersaline lake, in Antarctica and the marine environment

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    Dimethyl sulfoxide (DMSO) occurs worldwide, especially in marine environments as well as in lakes and rainwater. DMSO respiration by bacteria is assumed to play an important role in the sulfur cycle in Antarctica and on earth. We first studied whether DMSO-respiring bacteria existed in Antarctica. Eight strains were isolated that grew by DMSO respiration under anaerobic conditions from water of the halocline in a meromictic lake, Suribati Ike, near Syowa Station in Antarctica. All of them were related to known species belonging to the genus Marinobacter based on 16S rRNA gene sequences. Using a clone library analysis of 16S rRNA gene sequences, 38 of total 48 clones from water of the halocline were identified as Marinobacter. Studies on the various anaerobic respiration capabilities by bacteria in the halocline water found only DMSO respiration. Studies on bacteria with anaerobic respiration abilities in seawater from the Pacific Ocean and Seto Inland Sea, showed that either DMSO-respiring or nitrate-respiring bacteria were present and that all of isolates capable of DMSO respiration were closely related to Vibrio species
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