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Shuichi Miyazaki - One of the best experts on this subject based on the ideXlab platform.

  • heating induced martensitic transformation and time dependent shape Memory Behavior of ti nb o alloy
    Acta Materialia, 2014
    Co-Authors: Hideki Hosoda, Shuichi Miyazaki, Tomonari Inamura, H. Y. Kim, Masaki Tahara, Takafumi Kanaya
    Abstract:

    Abstract The temperature dependence of nano-sized lattice modulation (nanodomains) introduced by oxygen atoms and martensitic transformation Behavior of the (Ti–23Nb)–1.0O alloy were systematically investigated. Nanodomains in the β phase became unstable at higher temperatures and disappeared >373 K, where time-dependent heating-induced forward transformation (HIFT) was confirmed in the (Ti–23Nb)–1.0O alloy. The thermally activated process of HIFT in the (Ti–23Nb)–1.0O alloy was the diffusion of oxygen atoms in nanodomains. Anomalous temperature dependence of shape Memory Behavior was also confirmed in the (Ti–23Nb)–1.0O alloy, and its mechanism was successfully explained by the diffusion of oxygen atoms during tensile deformation.

  • effect of ternary alloying elements on the shape Memory Behavior of ti ta alloys
    Acta Materialia, 2009
    Co-Authors: Pio John S Buenconsejo, Shuichi Miyazaki
    Abstract:

    Abstract The effect of ternary alloying elements (X = V, Cr, Fe, Zr, Hf, Mo, Sn, Al) on the shape Memory Behavior of Ti–30Ta–X alloys was investigated. All the alloying elements decreased the martensitic transformation temperatures. The decrease in the martensitic transformation start (Ms) temperature due to alloying was affected by the atomic size and number of valence electrons of the alloying element. A larger number of valence electrons and a smaller atomic radius of an alloying element decreased the Ms more strongly. The effect of the alloying elements on suppressing the aging effect on the shape Memory Behavior was also investigated. It was found that the additions of Sn and Al to Ti–Ta were effective in suppressing the effect of aging on the shape Memory Behavior, since they strongly suppress the formation of ω phase during aging treatment. For this reason the Ti–30Ta–1Al and Ti–30Ta–1Sn alloys exhibited a stable high-temperature shape Memory effect during thermal cycling.

  • shape Memory Behavior of ti ta and its potential as a high temperature shape Memory alloy
    Acta Materialia, 2009
    Co-Authors: Pio John S Buenconsejo, Hideki Hosoda, H. Y. Kim, Shuichi Miyazaki
    Abstract:

    Abstract In this study, the effect of Ta content on shape Memory Behavior of Ti–Ta alloys was investigated. The shape Memory effect was confirmed in Ti–(30–40)Ta alloys. The martensitic transformation start temperature (Ms) decreased by 30 K per 1 at.% Ta. The amount of ω phase formed during aging decreased with increasing Ta. A stable high-temperature shape Memory effect was confirmed for Ti–32Ta (Ms = 440 K) during thermal cycling between 173 and 513 K. On the other hand, the high-temperature shape Memory effect of Ti–22Nb, which has a similar Ms to Ti–32Ta, exhibited poor stability due to the large amount of ω phase formed during thermal cycling. It is suggested that Ti–Ta is an attractive candidate for the development of novel high-temperature shape Memory alloys.

  • effect of ta addition on shape Memory Behavior of ti 22nb alloy
    Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2006
    Co-Authors: H. Y. Kim, Jae Il Kim, Hideki Hosoda, S. Hashimoto, Tomonari Inamura, Shuichi Miyazaki
    Abstract:

    Abstract Effect of Ta addition on microstructure and shape Memory Behavior of a Ti–22 at.%Nb alloy was investigated in order to improve the shape Memory and superelastic properties. The mechanical properties and shape Memory Behavior of Ti–22 at.%Nb–(0–8 at.%)Ta alloys were investigated by tensile tests at various temperatures and thermal cycling tests under various constant stresses. The shape Memory effect with the maximum recovery strain of 2.7% was observed at room temperature in the Ti–22Nb alloy. The martensitic transformation temperature of the Ti–22Nb alloy decreased by 30 K per 1 at.% addition of Ta. The superelastic strain increased with increasing Ta content. Almost perfect superelastic Behavior was observed until 2% tensile strain in the Ti–22Nb–(6–8)Ta alloys. The apparent yield stress decreased with increasing Ta content reaching a minimum yield stress around 4 at.%, and then the yield stress increased by further addition of Ta. The critical stress for slip increased with increasing Ta content. A higher critical stress for slip and a lower stress for inducing martensitic transformation resulted in a larger shape recovery strain above 3.0% in the Ti–22Nb–(4–6)Ta alloys.

  • texture and shape Memory Behavior of ti 22nb 6ta alloy
    Acta Materialia, 2006
    Co-Authors: H. Y. Kim, T T Sasaki, Jae Il Kim, Hideki Hosoda, Kayu Okutsu, Tomonari Inamura, Shuichi Miyazaki
    Abstract:

    Abstract Textures of cold-rolled and heat treated plates of Ti–22Nb–6Ta alloy were investigated by X-ray diffraction measurements. A well-developed { 0 0 1 } 〈 1 1 ¯ 0 〉 texture was obtained in the as-rolled specimen and after heat treatment at 873 K for 600 s. A recrystallization texture of { 1 1 2 } 〈 1 1 ¯ 0 〉 was developed after heat treatment at 1173 K for 1.8 ks. Anisotropy in the shape recovery strain and Young’s modulus was observed in both specimens heat treated at 873 and 1173 K. For the specimen heat treated at 873 K, a large recovery strain of 3.4% was observed when the loading axis is along the rolling direction (RD) and the transverse direction (TD). On the other hand, recovery strain took the largest value along the RD and the lowest value along the TD for the specimen heat treated at 1173 K. The experimental results on orientation dependence of transformation strain were in good agreement with calculated results utilizing the texture information and lattice correspondence between martensite and parent phases.

Yongqing Zhao - One of the best experts on this subject based on the ideXlab platform.

James E Payne - One of the best experts on this subject based on the ideXlab platform.

  • u s disaggregated renewable energy consumption persistence and long Memory Behavior
    Energy Economics, 2013
    Co-Authors: Carlos Pestana Barros, Luis A Gilalana, James E Payne
    Abstract:

    This study examines the degree of time persistence in U.S. disaggregated renewable energy consumption (hydropower, geothermal, solar, wind, wood, waste, and biofuels) using innovative fractional integration and autoregressive models with monthly data for the period 1994:2 to 2011:10. The results indicate that in the case of hydropower, solar, wind, waste, and biofuels the estimates of fractional integration are higher than 0.5 but less than 1.0 implying nonstationary, but mean reverting Behavior. In the case of geothermal and waste the estimates of fractional integration are around 0.5 and in the boundary case between stationarity and nonstationarity. For wood, the estimate of fractional integration is significantly smaller than 0.5 and thus showing stationary Behavior with long Memory Behavior. Furthermore, the study incorporates the presence of breaks in the data with the absence of breaks in hydropower, geothermal, solar, wind, wood, and biofuels, but a single break in the case of waste due to the inclusion of non-renewable waste from non-biogenic sources through 2000. The results reveal that U.S. disaggregated renewable energy consumption measures are better explained in terms of a long Memory model that incorporates persistence components and seasonality.

  • evidence of long Memory Behavior in u s renewable energy consumption
    Energy Policy, 2012
    Co-Authors: Carlos Pestana Barros, Luis A Gilalana, James E Payne
    Abstract:

    This study examines the degrees of time persistence in U.S. total renewable energy consumption using innovative fractional integration and autoregressive models with monthly data from 1981:1 to 2010:10. The results indicate that renewable energy consumption is better explained in terms of a long Memory model that incorporates persistence components and seasonality. The degree of integration is above 0.5 but significantly below 1.0, suggesting nonstationarity with mean reverting Behavior. The presence of long Memory Behavior (persistence) in renewable energy consumption suggests that random shocks may very well move renewable energy consumption from pre-determined target levels for a period of time.

  • does energy consumption by the us electric power sector exhibit long Memory Behavior
    Energy Policy, 2010
    Co-Authors: Luis A Gilalana, David G Loomis, James E Payne
    Abstract:

    This communication analyzes the energy consumption by the U.S. electric power by various energy sources through fractional integration. In doing so, we are able to determine the level of persistence of the shocks affecting each energy source. The results indicate long Memory Behavior as each energy source is highly persistent, displaying long Memory along with autoregressive Behavior and strong seasonal patterns.

Lihua Zhang - One of the best experts on this subject based on the ideXlab platform.

J M Kenny - One of the best experts on this subject based on the ideXlab platform.

  • design of biodegradable blends based on pla and pcl from morphological thermal and mechanical studies to shape Memory Behavior
    Polymer Degradation and Stability, 2016
    Co-Authors: Ivan Navarrobaena, Valentina Sessini, Franco Dominici, Luigi Torre, J M Kenny, Laura Peponi
    Abstract:

    Abstract Blending commercial homopolymers represents a low cost and an easy scalable process to extend the use of the pristine homopolymers to an industrial level. Actually, the processing of blends by extrusion is the usual solution followed in the industry. However, commonly polymer blends are immiscible, provoking phase separation, which can be in the macro, micro or nano scale, depending on the polymers as well as on the processing conditions, affecting the final properties of the blends. Therefore, this paper aims to study the shape Memory Behavior in biodegradable blends based on poly(lactic acid) (PLA) and poly(e-caprolactone) (PCL) in different concentrations. A completely thermal and mechanical characterization of the blends was performed, correlating the results with the observed morphology. In addition, two different biodegradation studies were performed in order to correlate the effect of each homopolymer with the degradation Behavior of the biodegradable blends.

  • nonvolatile Memory Behavior of nanocrystalline cellulose graphene oxide composite films
    Applied Physics Letters, 2014
    Co-Authors: L Valentini, Marta Cardinali, Elena Fortunati, J M Kenny
    Abstract:

    With the continuous advance of modern electronics, the demand for nonvolatile Memory cells rapidly grows. In order to develop post-silicon electronic devices, it is necessary to find innovative solutions to the eco-sustainability problem of materials for nonvolatile Memory cells. In this work, we realized a resistive Memory device based on graphene oxide (GO) and GO/cellulose nanocrystals (CNC) thin films. Aqueous solutions of GO and GO with CNC have been prepared and drop cast between two metal electrodes. Such thin-film based devices showed a transition between low and high conductivity states upon the forward and backward sweeping of an external electric field. This reversible current density transition Behavior demonstrates a typical Memory characteristic. The obtained results open an easy route for electronic information storage based on the integration of nanocrystalline cellulose onto graphene based devices.

  • synthesis and characterization of pcl plla polyurethane with shape Memory Behavior
    European Polymer Journal, 2013
    Co-Authors: Laura Peponi, Ivan Navarrobaena, J M Kenny, Agueda Sonseca, Enrique Gimenez, Angel Marcosfernandez
    Abstract:

    We are indebted to the Ministry of Science and Innovation (MICINN) in Spain for their economic support of this research (MAT2010-21494-C03-03; MAT 2011-25513) and for the access to the beamline BM16 (experiment 16-2-87) of the European Synchrotron Radiation facility (ESRF) in Grenoble (France). We are grateful to Dr. Ana Labrador and Dr. Francois Fauth for their help at BM16 station at the ESRF. LP also acknowledges MICINN for a Juan de la Cierva grant.