Monitoring of a calcination reaction of high reflective green-black (HRGB) pigments by using near-infrared electronic spectroscopy: calcination temperature-dependent crystal structural changes of their components and calibration of the extent of the reaction

This paper demonstrates the potential of near-infrared (NIR) electronic spectroscopy in nondestructive monitoring of a chemical reaction of inorganic functional material. For this purpose NIR spectra in the 12,000-4000 cm(-1) region were measured for high reflective green-black (HRGB) pigments (Co(0.5)Mg(0.5)Fe(0.5)Al(1.5)O(4)) calcined at 1000, 1100, and 1200 °C and pigments with the same components as HRGB but calcined at different temperatures (500-900 °C) (hereafter, called "Pigments A") . NIR spectra of their components such as Co(3)O(4), MgO, Fe(2)O(3), and Al(2)O(3) were also measured. The NIR spectra of Pigments A show two major broad bands. One arises from a (4)A(2)→(4)T(1) (T(h)) d-d transition of Co(II) in the 9000-6000 cm(-1) region. The other band in the 12,000-9000 cm(-1) region is assigned to a foot of the charge-transfer (CT) band of Fe(2)O(3). The Co(II) band contains three component bands that are characteristic of a spinel structure. A shoulder arising from (A(1-x)B(x))(Th)(A(x)B(2-x))(Oh)O(4) (A≡Co, Mg, B≡Fe, Al; inverse spinel structure) emerges near 5900 cm(-1) in the spectra of Pigments A calcined in the temperature range of 700-900 °C, indicating that the Pigments A calcined in this temperature range assume an inverse spinel structure. When the calcination temperature is above 1000 °C, the final product, HRGB, is produced. This is confirmed from the fact that HRGB shows peaks characteristic of a spinel structure that have different wavenumbers from those of the corresponding peaks of Pigments A. Wide-angle X-ray diffraction (WAXD) patterns were also measured for HRGB, Pigments A, and their components. Based on the NIR and WAXD data we investigated calcination-temperature-dependent crystal structural changes of the components. We also developed partial least squares (PLS) calibration models for the 9000-6000 cm(-1) region of the NIR spectra of HRGB and Pigments A. The score plot of latent variable (LV) 2 of the calibration model for calcination temperature demonstrates clearly the existence of an intermediate of the calcination reaction, which may be (A(1-x)B(x))(Th)(A(x)B(2-x))(Oh)O(4) (A≡Co, Mg, B≡Fe, Al).     

Discovery of unusual regional social activities using geo-tagged microblogs

The advent of microblogging services represented by Twitter evidently stirred a popular trend of personal update sharing from all over the world. Furthermore, the recent mobile device and wireless network technologies are greatly expanding the connectivity between people over the social networking sites. Regarding the shared buzzes over the sites as a crowd-sourced database reflecting a various kind of real-world events, we are able to conduct a variety of social analytics using the crowd power in much easier ways. In this paper, we propose a geo-social event detection method by finding out unusually crowded places based on the conception of social networking sites as a social event detector. In order to detect unusual statuses of a region, we previously construct geographical regularities deduced from geo-tagged microblogs. Especially, we utilize a large number of geo-tagged Twitter messages which are collected by means of our own tweets acquisition method in terms of geographic relevancy. By comparing to those regularities, we decide if there are any unusual events happening in monitoring geographical areas. Finally, we describe the experimental results to evaluate the proposed unusuality detection method on the basis of geographical regularities which are computed from a large number of real geo-tagged tweet dataset around Japan.     

Development of a digital control system for high-performance pneumatic servo valve

Pneumatic servo systems are used in many fields, such as pneumatic robot systems or vibration isolation systems. To improve the controllability of the pneumatic servo system, a higher performance servo valve is needed.In the present paper, a pneumatic spool type servo valve having an air bearing and a high-resolution position sensor was developed. We attempted to achieve high-frequency, high-accuracy flow rate control by digitization of the controller. We present herein a control algorithm for digital control of this valve.The characteristics of this valve were measured and the natural frequency of the valve was clarified to be up to 300 Hz. The spool position accuracy and the dynamic characteristics of the developed servo valve are greatly improved compared to existing valves.     

C32: Computations of Low-Energy Cages with Four-Membered Rings

C₃₂ cages built from four-, five-, six-, and seven-membered rings are computed. The computations are primarily performed with semiempirical quantum-chemical methods (AM1, PM3, SAM1), and altogether 199 cages are optimized. The energetics is further checked through ab initio HF SCF computations with the standard 3-21G basis set, and also by density functional theory at the B3LYP level in the standard 6-31G* basis set. All five levels of theory suggest a D_4d cage (two four-membered rings, eight pentagons, eight hexagons) as the lowest-energy structure. Temperature effects are treated in the terms of partition functions so that the entropy contributions are considered accordingly. The thermodynamic treatment points out five cages significantly populated at high temperatures. At very high temperatures the structure lowest in energy is not the most abundant isomer. There are just six conventional fullerenes C₃₂, built exclusively from pentagons and hexagons, however, only two of them show significant populations at high temperatures. The remaining three relatively stable cages contain at least one four-membered ring. No structure with a heptagon shows a non-negligible concentration at high temperatures. The study suggests that in the non-IPR region the quasi-fullerene cages with four-membered rings can in some cases be more important than the conventional fullerenes built from pentagons and hexagons only.     

Molecular dynamics simulation for the crystal structure of synthetic sugar-based bolaamphiphiles

We have performed molecular dynamics simulations for the crystals of synthetic sugar-based bolaamphiphiles with two D-galactosyl- or D-glucosylamine rings, using the Parrinello–Rahman–Nosé method with Dreiding force field to understand the origin of a bend structure of 1-galactosamino bolaamphiphile (Gal-10-Gal) in a crystalline phase. Intermolecular interaction energy between nearest neighbor molecules which arrange in a layer is larger than the energy between interlayer molecules. Intermolecular interaction (especially van der Waals and electrostatic interaction) between the Gal-10-Gal molecules within the layer contributes to stabilization of the crystal structure of Gal-10-Gal. Bending of the Gal-10-Gal molecule minimizes hydrogen bonding energy and electrostatic energy between the nearest neighbor Gal-10-Gal molecules.     

Human Polymerase δ-Interacting Protein 2 (PolDIP2) Inhibits the Formation of Human Tau Oligomers and Fibrils

A central characteristic of Alzheimer’s disease (AD) and other tauopathies is the accumulation of aggregated and misfolded Tau deposits in the brain. Tau-targeting therapies for AD have been unsuccessful in patients to date. Here we show that human polymerase δ-interacting protein 2 (PolDIP2) interacts with Tau. With a set of complementary methods, including thioflavin-T-based aggregation kinetic assays, Tau oligomer-specific dot-blot analysis, and single oligomer/fibril analysis by atomic force microscopy, we demonstrate that PolDIP2 inhibits Tau aggregation and amyloid fibril growth in vitro. The identification of PolDIP2 as a potential regulator of cellular Tau aggregation should be considered for future Tau-targeting therapeutics.     

Effect of sodium on repair weldability of SUS316FR for a fast breeder reactor

The effect of sodium on repair weldability of SUS316FR steel under the remaining sodium environment was investigated by transverse-Varestraint and laser cladding tests. Solidification brittle temperature range (BTR) of SUS316FR steel with AF solidification mode was 37 K. However, BTR was expanded from 37 to 67 K, as the amount of surface-adhered sodium increased from 0 to 7.99 mg/cm². From microstructural observation of the weld metal, there would be a possibility that metallic sodium existed at cell boundaries in the weld metal during welding solidification. According to the thermodynamic calculation, the sodium would expand the solid–liquid coexistence temperature range. It could be concluded that the enhanced solidification cracking susceptibility under the sodium environment would be attributed to the enlargement of the solid–liquid coexistence temperature range. Finally, it was confirmed that any solidification cracks and blowholes did not occur in the overlaid weld metal through multipass laser cladding tests. Namely, it could be confirmed that SUS316FR steel possessed superior repair weldability under the sodium environment.     

Prediction of corrosion products of iron at a low-level radioactive waste disposal facility in Japan

Estimation of the volumetric expansion ratio due to the corrosion of metals is an essential part of the safety assessment of low-level radioactive waste disposal facilities in Japan, because such volumetric expansion can disrupt the barrier function of these facilities. In the present study, the corrosion products of iron were predicted from potential–pH diagrams and the results of a synthesis test, and the volumetric expansion ratios of the corrosion products were evaluated. Under a basic set of conditions expected at a disposal facility over a storage period of a thousand to tens of thousands of years, Fe₃O₄, Fe₂O₃, and FeOOH were predicted as the major stable corrosion products of iron. The maximum volumetric expansion ratio determined from the true density of these products was 2.9, and the maximum volumetric expansion ratio, assuming the generation of voids in the corrosion products, was 3.7, which is the Pilling–Bedworth ratio of Fe(OH)₂. The volumetric expansion ratio may increase in the presence of carbonate ions in a long-term environment with a reduced pH.     

Direct length comparison between regular crystalline lattice and SEM standard grating using dual tunneling unit STM

This paper presents a potential image processing method for calibrating the in-plane geometrical distortion of a scanning tunneling microscope (STM) image using a regular crystalline lattice, describes the assessment evaluation of comparative length measurement in the range of about 1 micrometer using a regular crystalline lattice as a reference scale and a dual tunneling unit-STM (DTU-STM) as a detector, and shows the results of direct length comparison between a scanning tunneling microscope (SEM) standard grating, whose pitch is 240 nm, and a regular crystalline lattice using a DTU-STM. The method is based on two-dimensional fast Fourier transform (FFT) analysis. The DTU- STM with one X-Y stage and two tunneling units independently controlled in the Z-axis direction has been utilized for comparative length measurement. To improve the measurement accuracy, the present method is used to process the raw images obtained from the DTU-STM. The results of assessment experiments, in which the cleaved surface of highly oriented pyrolytic graphite (HOPG) is used as a reference scale for measurement of lengths on the order of 1 micrometer, demonstrate the feasibility of the present image processing method and the comparative length measurement with sub-nanometer resolution using the DTU- STM. The value of the SEM standard grating pitch, which obtained from the direct length comparison with HOPG lattice spacing using the DTU-STM, was coincided with the value obtained from the conventional diffraction method within a error of 2 %.