Defining the nanostructured morphology of triblock copolymers using resonant soft X-ray scattering

The morphologies of a poly(1,4-isoprene)-block-polystyrene-block-poly(2-vinyl pyridine) (IS2VP) copolymer were investigated using resonant soft X-ray scattering (RSoXS) together with scanning force microscopy, small-angle X-ray scattering, and electron microscopy. Differences in the nanoscopic morphologies in the bulk and thin film samples were observed arising from the competition between segmental interactions between the blocks and the substrate and the surface energies of each block. Using soft X-rays at selected photon energies to isolate the scattering contribution from different polymer blocks, RSoXS unambiguously defined the complex morphology of the triblock copolymer. In the bulk sample, two nested, hexagonal arrays of P2VP and PI cylindrical microdomains residing in the PS matrix were observed. The cylindrical microdomains of one component were found to be located at the interstitial sites of the hexagonal array of the other component that has the larger d spacing. In solvent-annealed thin films with 40 nm in thickness, a hexagonal array of core-shell microdomains of P2VP cores with PS shells that reside in a PI matrix were observed.     

Vacuolar H(+)-ATPase and plasma membrane H(+)-ATPase contribute to the tolerance against high-pressure carbon dioxide treatment in Saccharomyces cerevisiae

As a non-thermal sterilization process, high-pressure carbon dioxide treatment (HPCT) is considered to be promising. The main sterilizing effect of HPCT is thought to be acidification in cytoplasm of microorganisms. We investigated the tolerance mechanism of Saccharomyces cerevisiae to HPCT with special reference to vacuolar and plasma membrane H(+)-ATPases. HPCT was imposed at 35 degrees C, 4 to 10 MPa, for 10 min. slp1 mutant defective in vacuole morphogenesis was more sensitive to HPCT than its isogenic parent. Concanamycin A, a specific inhibitor of vacuolar H(+)-ATPase (V-ATPase), at 10 microM rendered the parent more HPCT-sensitive to the level of slp1. To confirm further the contribution of V-ATPase to the tolerance against HPCT in S. cerevisiae, we compared vma1 mutant of V-ATPase with its isogenic parent for their HPCT sensitivity. vma1 mutant was more sensitive to HPCT than its parent. Addition of 10 microM vanadate, an inhibitor of plasma membrane H(+)-ATPase (P-ATPase), to the wild type strains also increased the inactivation ratio. These results clearly show that V- and P-ATPases contribute to the tolerance against HPCT in S. cerevisiae by accumulating excess H(+) from cytoplasm to vacuole and excluding H(+) outside of the cell, respectively.     

Inserting polyoxomolybdate cluster into poly(?-caprolactone) to create a class of new heteropolymer: Synthesis and supramolecular structures

In the present work, we report our work concerning the synthesis of heteropolymers of poly(?-caprolactone)-polyoxomolybdate-poly(?-caprolactone) using ring-opening polymerization (ROP) of ?-caprolactone monomer initiated by two hydroxyl groups attached on the two sides of a polyoxomolybdate cluster which was organically modified using pentaerythritols. Since the hydroxyl groups on polyoxomolybdate macroinitiator are less reactive, ring-opening polymerization were finally carried out by using 4,4′-(dimethylamino) pyridine to activate ?-caprolactone monomer. The polyoxomolybdate-containing heteropolymers were confirmed in detail by ¹H NMR, FT-IR, GPC, TGA and XPS methods. Although the size of polyoxomolybdate cluster is extremely small compared to PCL chains, it was also found that POM played an important role in crystallization process. Self-assembly of such heteropolymers in mixed solvents were investigated and the analysis of formed spherical aggregates with multiple concaves on the surface was supported by TEM results and 3D electron tomography.     

Highly Efficient Extraction of Rhodium(III) from Hydrochloric Acid Solution with Amide-Containing Tertiary Amine Compounds

Extraction of Rh(III) from a HCl solution with N,N-disubstituted amide–containing tertiary amine (ACTA) compounds (N,N-di-n-hexyl(N-methyl-N-n-octyl-ethylamide)amine (MonoAA), N-n-hexyl-bis(N-methyl-N-n-octyl-ethylamide)amine (BisAA), and tris(N-methyl-N-n-octyl-ethylamide)amine (TrisAA)) was investigated. The ACTAs extract Rh(III) more efficiently than tri-n-octylamine (TOA), and the extraction efficiency increases with increasing number of amide groups: TrisAA > BisAA > MonoAA ? TOA. For all ACTAs, the predominant Rh(III) complex extracted from 2 M HCl is probably {[RhCl₅(H₂O)]·(ACTA·H)₂}. The apparent basicity of the ACTAs and TOA varies in the opposite order from that observed for the Rh(III) extraction efficiency. Rh(III) can be readily back-extracted using 10 M HCl solution possessing a high selectivity over similarly loaded Pd(II) and Pt(IV).     

Next Day Peak Load Forecasting Using Neural Network With Adaptive Learning Algorithm Based On Similarity

In this article we propose the adaptive learning algorithm of neural network with respect to a rapid temperature change of forecasted day. The proposed adaptive learning algorithm is used to shift the learning range of previous year of forecasted day. Therefore, the proposed neural network can be trained by using learning data, including the maximum temperature to be forecasted. The suitability of the proposed approach is illustrated through an application to actual load data of Okinawa Electric Power Company in Japan.     

A New Form of Rolling Contact Damage in Grease-Lubricated,Deep-Groove Ball Bearings

A new form of rolling contact damage was discovered in the fatigue tests of series 6206 deep groove ball bearings under pure radial load with grease lubrication. The appearance of the damage reveals a few cracks at right angles to the rolling direction of the ball, along with the formation of a dent about 20 μ m deep in the raceway surface. This is found to occur only on the stationary outer ring raceway and the ball surface and is distributed widely within the load zone. Furthermore, under the raceway surface several cracks propagating into the substrate at an angle of about 60-80 degrees relative to the raceway surface are observed not only under the damage site but also in other nearby locations. Only the cracks at the damage position open up to the surface. The grease used for the test contained a lithium complex thickener with mineral oil as the base oil with a kinematic viscosity of 141 mm²/s at 40°C. On the test bearings two pure radial load levels of 9.14 and 12.13 kN were applied. In order to prevent the occurrence of seizure at each load, the speed of the inner ring of the test bearing was maintained at 1800-2500 min^{? 1} and 600-800 min^{? 1}, respectively, to keep the outer ring circumference temperature below 65°C. It is suggested that the damage is caused by metal-to-metal contacts due to lubricant starvation under grease lubrication and to a decrease in oil film thickness due to local increases in temperature.