A straight-shaped Ti-Ni shape memory alloy (SMA) element shows negative stiffness during post-buckling deformation, and the buckling deformation is recovered with unloading due to the shape memory properties (superelastic behavior). This negative stiffness and shape recovery properties are applied to a passive vibration isolator using a zero-stiffness structure. We devised and fabricated the passive vibration isolator using the negative stiffness of tape-shaped SMA element, and this isolator shows the excellent vibration characteristic. However, control of the magnitude of the negative stiffness of the SMA element during post-buckling deformation is necessary for this isolator. In previous our studies, the variation of tangential stiffness of SMA element during post-buckling deformation is thought to be due to the variation of the volume fraction of martensitic-phase during post-buckling deformation by Three-dimensional finite element method (3D-FEM) analyses. In this study, effects of the volume fraction of martensitic-phase during buckling deformation on post-buckling behavior of tape-shaped SMA element are investigated by actual buckling tests for tape-shaped SMA elements with various length and 3D-FEM analyses. The results of buckling tests and 3D-FEM analyses suggest that the increase of the negative tangential stiffness during post-buckling deformation is due to the increase in the rate of increase of the volume fraction of the martensitic-phase during buckling deformation.
Aiming at the development of a filter material that can be used for livestock wastewater treatment, a sintered filter was manufactured by combining recycled carbon with ceramics. We investigated the possibility of applying this filter to the decolorization treatment of the color-causing substances contained in wastewater. Humic acid was used as a model of the color-causing substances. The possibility of regenerating a carbon-ceramic sintered filter after the adsorption treatment by heat treatment and repeated use was examined. When an aqueous solution of sodium humic acid was poured into the sintered carbon-ceramic filter, it was found that it has a high adsorption capacity for humic acid. However, when the aqueous solution was continuously poured, the adsorption rate of humic acid decreased. When the sintered carbon-ceramic body used in the adsorption experiment was heat-treated in an air atmosphere, the adsorption capacity was restored through the heat treatment at 400 °C to 500 °C. From the above, it was shown that a sintered carbon-ceramic body can be an effective adsorbent for humic acid, which is a coloring substance for livestock wastewater and can be repeatedly used for heat treatment.
Keggin-type polyoxometalate clusters were successfully hybridized with a polymerizable ionic-liquid having methacryloyl group and imidazolium moieties (denoted as MAImC1). Metatungstate ([H2W12O40]6−, H2W12) and dodecamolybdophosphate ([PMo12O40]3−, PMo12) anions were firstly employed to obtain inorganic-organic hybrid crystals. Their compositions and structures were clearly revealed by single crystal structure analyses.
In the present study, we investigated the effects of ceramic paint on indoor conditions and comfort of two wooden houses with single-story during winter; the one house had ceramic paint on the outermost layer of interior finishing material, the other had no coating. These houses showed significant differences in the indoor temperature and relative humidity regardless of heating, although the comparison of differences in numerical values was small. Similar differences were also found in temperatures between surfaces of forehead and foot back of test subjects; test subjects in the house with coating often showed smaller values during measurement. These trends were clearly reflected in to the sensible temperature of them. Test subjects in the house with coating clearly indicated the indoor comfort than other one. It is possible that the use of the ceramic paint slightly relieves the resident of feeling cold.
The purpose of this study is the efficient production of long-wavelength UV absorbing lignin oligomers by accelerating their formation reactions. In previous study, several oligomers were isolated from lignin alkaline cupric (II) oxide (CuO) oxidative degradation products and were expected to be used in value-added applications. Some of these lignin oligomers are estimated to be formed via aldol condensation reactions between lignin degradation monomers and acetone. For efficient production, acetone was added as a raw material to hardwood alkaline CuO oxidative degradation system. As a result of acetone addition, the yields of oligomers in the lignin degradation products increased as the amount of acetone increase. LC-MS analysis of the degradation products showed that aldol condensation products were increased compared to the without acetone. Furthermore, a model experiment was conducted that vanillin and syringaldehyde were used as lignin degradation product models. This experiment showed that the addition of acetone to the lignin alkaline CuO oxidative degradation system promoted the aldol condensation reaction due to the formation of dehydrozingerone.
It is important that lignin convert to high value-added product for effective utilization. It is said that lignin has little physiologically activity, although the various polyphenols of similar structure to lignin, for example lignans, flavonoids, stilbene, have various physiologically activity. In this study the physiologically active compounds molecularly designed from lignin based on structure of high activity polyphenols. The objective structure characteristic of lignin derivatives is as follows. 1) Phenolation of lignin with 1,2-dihydroxy aromatic derivatives, 2) Conversion of native lignin to β-O-4 type lignin, 3) Control of molecular weight (Mw1000-3000), 4) Conversion to long conjugate structure. o-Dihydroxy phenolation and conversion of native lignin to β-O-4 type lignin were achieved by phase separation system with catechol. Control of molecular weight of lignin derivatives and induction of long conjugate structure were occurred by alkaline cupric (CuO) oxidative degradation. The structure characteristic of lignin derivatives through the these treatment were analyzed by PDA-GPC, LC-MS and FT-IR. The antioxidative activity of lignin derivatives were largely similar to catechin in spite of polymer, extremely useful as physiologically active compounds from lignin.
The effect of oxidation and the subsequent vacuum annealing on the electrical and structural properties of Ga-doped ZnO (GZO) films prepared by sputtering was investigated with respect to annealing temperature and time. The annealing of the GZO films in air caused severe reduction in carrier density, but subsequent vacuum annealing partially recovered the carrier density. This change in carrier density indicates that oxygen atoms are easily incorporated into and released from the GZO film. As the vacuum annealing time increased at an annealing temperature of 500 °C, the recovery of the carrier density peaked and then decreased. This annealing-time dependence is attributed to the co-desorption of oxygen and zinc and indicates that oxygen diffusion is faster than that of zinc in Ga-doped ZnO films. Air annealing reduces the carrier density and mobility of films. However, subsequent vacuum annealing results in the recovery of the carrier density and the enhancement of mobility, depending on the annealing temperature. The enhancement of mobility suggests that an adequate arrangement of incorporated oxygen atoms at the grain boundary reduces carrier scattering in GZO films.
Commercialized silicoaluminophosphate-34 (SAPO-34) zeolite was successfully blended in the polyethersulfone (PES) polymer to prepare the mixed matrix membranes (MMMs). The CO2 permeability and CO2/CH4 ideal selectivity of 30 wt% SAPO-34/PES MMM at 0.1 MPa and 35 °C were 15 barrer and 51, respectively. In our previous paper, the PES MMMs using laboratory-made SAPO-34 provided both higher permeability and selectivity than the neat PES membrane. The performance of the commercial SAPO-34 filled MMMs in this study exceeded their performance. We also investigated the performance of these MMMs in terms of gas diffusivity and solubility. The increase in the diffusivity selectivity was greater for the commercial SAPO-34 MMMs than for the laboratory-made SAPO-34 MMMs. The difference was attributed to the amounts of defects. The performance of the MMMs in this study was also superior to that of the reported SAPO-34/PES MMMs in literature where the filler surface was modified to improve the compatibility of the filler and PES matrix. These results suggest that the use of the commercial SAPO-34 and an appropriate surface modification has the potential to improve the performance of the MMMs.
Tryptanthrin (T) and 2-fluorotryptanthrin (T2F) exhibit no fluorescence in the solid state. The presumption exists that this is due to the strong π-π stacking interaction resulting from the planar structure. However, the analogs, DCM-T and DCM-T2F, in which the 6-position carbonyl group is replaced with a stronger electron-withdrawing group, the dicyanomethylene group, exhibit fluorescence in the solid state despite the planar structure. The reasons for this were analyzed and discussed based on the results of X-ray crystal structure analysis.
We synthesized barium-substituted sodium bismuth titanates, (Na0.5Bi0.5-z)1-xBaxTiO3-d, without a Bi deficiency (z = 0) and with a Bi deficiency of z = 0.03 by the polymerizable complex method while preventing sodium and bismuth from evaporating. The maximum dielectric constant on the samples without a Bi deficiency (z = 0) was located around a Ba content of x = 0.10. On the other hand, the samples with a Bi deficiency of z = 0.03 indicated the maximum value of dielectric constant at approximately a Ba content of x = 0.06. These Ba contents were consistent with the morphotropic phase boundary (MPB) on each sample with the different Bi deficiencies.
Several composites were obtained by polycondensation reaction using metal phthalocyanine having carboxy groups and p-phenylenediamine. The obtained composites were pyrolyzed at 900 °C in a hydrogen stream to afford the cathode catalysts for polymer electrolyte fuel cells (PEFC). The catalysts were treated with aqua regia to investigate the influence of metal content on oxygen reduction activity (ORA). Comparing the ORA of the catalysts before and after the aqua regia treatment, the ones containing metal had higher activity. It became clear that the presence of metal is indispensable for improving ORA.