Temperature dependence of birefringence and stress for natural rubber vulcanizates at strained state

The temperature dependence of stress and birefringence for natural rubber vulcanizates under medium and large deformation was measured for the processes of cooling, heating and re-cooling. In order to investigate the relation between the stress and crystal phase, the observed birefringence, Δt, was converted into the crystallinity, X_v, by the following equation:

$\text{X}{}_{\mathrm{<mtext>v</mtext>}}\text{=}\text{Δt?Δn}{}_{\mathrm{<mtext>a</mtext>}}\text{°f}{}_{\mathrm{<mtext>a</mtext>}}\text{Δn}{}_{\mathrm{<mtext>c</mtext>}}\text{°f}{}_{\mathrm{<mtext>c</mtext>}}\text{?Δn}{}_{\mathrm{<mtext>a</mtext>}}\text{°f}{}_{\mathrm{<mtext>a</mtext>}}$

where Δn⁰_c, Δn⁰_a, f_a and f_c are the intrinsic birefringence of the crystal, that of the amorphous phase, the orientation factor of crystallites, and that of amorphous phase, respectively. The fusion of crystallites induced by the thermal crystallization resulted in the increasing contractile force, while the fusion of strain-induced crystallites induced the reduction of contractile force.     

Low core loss of Fe85Si2B8P4Cu1 nanocrystalline alloys with high Bs and B800

The Fe–Si–B–P–Cu nanocrystalline alloys exhibit high saturation magnetic flux density (B_s) as well as good soft magnetic properties such as low coercivity, high effective permeability and low magnetostriction after nanocrystallization. In this paper, the Fe₈₅Si₂B₈P₄Cu₁ alloy has been newly developed. On the viewpoint of magnetic softness, the Fe₈₅Si₂B₈P₄Cu₁ nanocrystalline alloy reveals low core loss (W) at a commercially frequency of 50 Hz in the maximum induction (B_m) range of up to 1.75 T, and the W in the B_m range of less than 1.8 T is smaller than that of the highest-graded oriented Si-steel due to high magnetic flux density at 800 A/m (B₈₀₀) of above 1.8 T and excellent magnetic softness originated from much higher Fe content and uniform nanocrystalline structure with small magnetostriction. The electrical resistivity (ρ) is relative higher than Si-steels. Thus the Fe–Si–B–P–Cu alloys are attractive for applying to magnetic parts such as motors, transducers, choke-coils and so-forth.     

Contrasting diurnal variations in fossil and nonfossil secondary organic aerosol in urban outflow, Japan

Diurnal variations of fossil secondary organic carbon (SOC) and nonfossil SOC were determined for the first time using a combination of several carbonaceous aerosol measurement techniques, including radiocarbon (1?C) determinations by accelerator mass spectrometry, and a receptor model (chemical mass balance, CMB) at a site downwind of Tokyo during the summer of 2007. Fossil SOC showed distinct diurnal variation with a maximum during daytime, whereas diurnal variation of nonfossil SOC was relatively small. This behavior was reproduced by a chemical transport model (CTM). However, the CTM underestimated the concentration of anthropogenic secondary organic aerosol (ASOA) by a factor of 4-7, suggesting that ASOA enhancement during daytime is not explained by production from volatile organic compounds that are traditionally considered major ASOA precursors. This result suggests that unidentified semivolatile organic compounds or multiphase chemistry may contribute largely to ASOA production. As our knowledge of production pathways of secondary organic aerosol (SOA) is still limited, diurnal variations of fossil and nonfossil SOC in our estimate give an important experimental constraint for future development of SOA models.     

Extraction of lanthanide ions from aqueous solution by bis(2-ethylhexyl)phosphoric acid with room-temperature ionic liquids

Extractions of five kinds of lanthanide metal ions by bis(2-ethylhexyl)phosphoric acid (DEHPA) with [1-Cn-3-methylimidazolium][PF₆](Cn = C₂, C₄) or [1-butyl-4-methylpyridinium][PF₆] were carried out under various DEHPA and HNO₃ concentrations from 0 to 1 M and under different temperature conditions from 298 to 333 K. These results were compared with those using the conventional organic solvent, hexane, in terms of their distribution coefficient values. Under all of the conditions in this study, the ionic liquid system shows more than three times greater extractability for lanthanide compared to when hexane was used. The distribution coefficient of lanthanide ions decreased as the length of the alkyl chain increased from the ethyl to the butyl. In addition, the imidazolium cation generally shows a higher distribution coefficient compared to the pyridinium cation in an ionic liquid. The concentration ratio of lanthanides and DEHPA resulted in an extraction affinity transition for lanthanides. Also evaluated in this study were issues related to the selectivity associated with the lanthanide mixture and the dependency of the ionic radius during lanthanide extraction.     

Hole Doping Mechanism in Bismuth Cuprates

The role of oxygen for the hole doping has been investigated for single-phased (Bi,Pb)₂Sr₂Ca₂Cu₃O. _z Defects introduced by oxygen have been clarified to be interstitial atoms by pycnometric density measurements. The c axis decreases and the modulation periods along the b axis also decrease with increasing oxygen content in the crystal. It is likely that extra oxygen ions exist between the BiO double layers and those oxygen ions are responsible for the modulation. Samples with oxygen content ranging from 9.99 to 10.18 showed superconductivity. The critical temperature T _c , exhibited a maximum value (109 K) at 10.07 oxygen atoms in the formula unit, which coincided with the average Cu valence of 2.13. The data indicated that hole formation was governed by oxygenation reaction in this system.     

Mechanical properties of porous titanium compacts prepared by powder sintering

Porous Ti compacts for biomedical applications are successfully fabricated in the porosity range from 5.0 to 37.1 vol% by controlling sintering conditions and Ti powder sizes. Young’s modulus and bending strength at the porosity of around 30 vol% are found to be similar to those of human cortical bone.     

In situ time-resolved X-ray diffraction of tobermorite formation in autoclaved aerated concrete: Influence of silica source reactivity and Al addition

The hydrothermal formation of tobermorite during the processing of autoclaved aerated concrete was investigated by in situ X-ray diffraction (XRD) analysis. High-energy X-rays from a synchrotron radiation source in combination with a newly developed autoclave cell and a photon-counting pixel array detector were used.To investigate the effects of the silica source, reactive quartz from chert and less-reactive quartz from quartz sand were used as starting materials. The effect of Al addition on tobermorite formation was also studied. In all cases, C-S-H, hydroxylellestadite and katoite were clearly observed as intermediates.Acceleration of tobermorite formation by Al addition was clearly observed. However, Al addition did not affect the dissolution rate of quartz. Two pathways, via C-S-H and katoite, were also observed in the Al-containing system. These results suggest that the structure of initially formed C-S-H is important for the subsequent tobermorite formation reactions.     

Novel stabilization system for polypropylene via the Ziegler–Natta catalyzed polymerization in the presence of aluminum aryloxide

The aluminum aryloxide was prepared via the reaction of phenolic antioxidant, 3‐(3,5‐di‐t‐butyl‐4‐hydroxyphenyl)‐N‐octadecylpropionamide, with triethyl aluminum. Propylene polymerization using supported Ziegler–Natta catalyst systems was carried out in the presence of the antioxidant or its aluminum aryloxide. Although the antioxidant gave rise to decrease in catalyst yield and change in hydrogen response, the aluminum aryloxide had no influence on the catalytic polymerization behavior, and thus the obtained polymer characteristics such as molecular weight, polydispersity, and meso pentad as a stereoregularity were comparable to that polymerized without the antioxidant and the aluminum aryloxide. Polypropylene obtained in the presence of the aluminum aryloxide was well stabilized for oxidation and its stability was over 1000 h at 100°C (estimated to be over 30 years at room temperature). © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1350–1358, 2006     

LiErO2 formation on Er2O3 in static and natural convection lithium

Er₂O₃ is candidate material for insulating coating to prevent the magnetohydrodynamic (MHD) pressure drop in the self-cooled liquid Li blanket system. Although Er₂O₃ is stable material, detailed chemical behavior in liquid Li is not clear. Corrosion behavior of bulk Er₂O₃ in Li is investigated in static and flowing condition in the present study. After these tests, good compatibility of Er₂O₃ was confirmed and slight formation of LiErO₂ was detected by XRD analysis. This chemical behavior did not change in a static and flowing tests, however some of the corrosion product of LiErO₂ was removed easily by the Li flow. Intensity of LiErO₂ peaks in XRD spectrum suggests that the temperature gradient may affect the reaction rate in the natural convection loop. Since corrosion rate of Er₂O₃ is very small, slight change in state will be important information to evaluate lifetime of coating.     

Denatured-jacalin derivatives with selective recognition for O-linked glycosides (ST,T, Tn,and STn Type) on IgA1 hinge region

Immunoglobulin A1 (IgA1) concentration in the plasma of patients with IgA nephropathy (IgAN) as the cause of renal failure is higher than that in the plasma of normal controls. IgA1 with abnormal sugars is considered to deposit in the glomerular mesangium, aggravating nephritis in IgAN. Jacalin is a lectin that recognizes sugars on IgA1. However, its selective-recognition for normal-type (ST type, NeuAc-α(2,3)-Gal-β(1,3)-GalNAc) and abnormal-type (T type, Gal-β(1,3)-GalNAc; Tn type, GalNAc; STn type, NeuAc-α(2,6)-GalNAc) sugars α-O-linked to serine/threonine in IgA1 is weak. Therefore, jacalin cannot be used for recognizing specific sugar types on IgA1. We attempted to develop a new recognition method for specific sugar types on IgA1 by utilizing the multirecognition capability of jacalin. Its binding abilities were regulated by heat denaturation with suitable template sugar (galactose or N-acetylgalactosamine). Further, we successfully prepared denatured-jacalin derivatives, which recognized ST-/T-type sugars on IgA1, by sugar-immobilized affinity chromatography. Enzyme-linked immunosorbent assay of denatured-jacalin derivatives, showed the ratios of abnormal sugars on IgA1 in the plasma of IgAN patients and normal controls to be approximately 60% and 20%, respectively. The results proved that profiling of sugar types in IgAN can successfully be performed by solely using jacalin derivatives.