Absorption of chlorine into aqueous sodium carbonate solutions and desorption of carbon dioxide

The absorption of pure chlorine into aqueous sodium carbonate solutions accompanied by the desorption of carbon dioxide was studied both theoretically and experimentally. The absorption rates of chlorine and the desorption rates of carbon dioxide were measured at 25°C using a baffled agitated vessel operated batchwise. The experimental results were analyzed with the chemical absorption theory based on the Lévěque model. The measured absorption and desorption rates were in good agreement with the theoretical predictions.     

Nanoparticle induced network self-assembly in polymer-carbon black composites

A novel percolation phenomenon with inorganic nanoparticle loading in polyamide 6-carbon based nanoparticle hybrids was identified. Percolation threshold substantially shifts to lower carbon black (CB) volume fractions in the presence of optimum concentration of chemically modified montmorillonite (organoclay) while the effective organoclay concentration can be optimized to lower the slope of percolation curve maintaining electrical conductivity within static dissipative 10⁻⁶-10⁻⁹ S cm⁻¹ range. Organoclay/CB ‘nano-unit’ morphology was found in polyamide 6 ternary hybrids. It is composed of stacked organo-montmorillonite platelets that deform to wrap partially around one or two primary CB aggregates. This elementary nano-unit structure induces CB network self-assembly within polyamide 6 matrices. The structure was found to be prevalent throughout the polymer matrix. This morphology remains robust under wide range of thermal-deformation histories due to the strong preferred organoclay/polyamide 6/CB interactions that partially blocks the electron conduction and hopping mechanisms with clay ‘walls’ thereby reducing the slope of the percolation curve. Organoclay can be used as a dispersion control agent in these polymer-carbon systems to induce self-assembly of CB network at low CB content, simultaneously, partial blocking the electron hopping pathways to level the slope of percolation curves. High order exfoliation and nano-scale dispersion of organoclay is essential to induce this advanced percolation phenomenon.     

In situ observation of initial rust formation process on carbon steel under Na2SO4 and NaCl solution films with wet/dry cycles using synchrotron radiation X-rays

Atmospheric corrosion of steel proceeds under thin electrolyte film formed by rain and dew condensation followed by wet and dry cycles. It is said that rust layer formed on steel as a result of atmospheric corrosion strongly affects the corrosion behavior of steel. The effect of environmental corrosiveness on the formation process and structure of the rust layer is, however, not clear to date. In this study, in situ observation of the rusting process of a carbon steel covered with a thin film of Na₂SO₄ or NaCl solution was performed under a wet/dry repeating condition by X-ray diffraction spectroscopy with white X-rays obtained from synchrotron radiation. The present in situ experiments successfully detected initial process of the rust formation. In the early cycles, the rust constituents were not well crystallized yet, but the presence of Fe(OH)₂ and Fe(OH)₃ was confirmed. In the subsequent cycles, two different solutions resulted in difference in preferential phase of the rust constituents. α-FeOOH was preferentially formed in the case of the Na₂SO₄ solution film, whereas β-FeOOH appeared only under the NaCl solution film.     

Combination of bottleneck feature extraction and dereverberation for distant-talking speech recognition

The performance of speech recognition in distant-talking environments is severely degraded by the reverberation that can occur in enclosed spaces (e.g., meeting rooms). To mitigate this degradation, dereverberation techniques such as network structure-based denoising autoencoders and multi-step linear prediction are used to improve the recognition accuracy of reverberant speech. Regardless of the reverberant conditions, a novel discriminative bottleneck feature extraction approach has been demonstrated to be effective for speech recognition under a range of conditions. As bottleneck feature extraction is not primarily designed for dereverberation, we are interested in whether it can compensate for other carefully designed dereverberation approaches. In this paper, we propose three schemes covering both front-end processing (cascaded combination and parallel combination) and back-end processing (system combination). Each of these schemes integrates bottleneck feature extraction with dereverberation. The effectiveness of these schemes is evaluated via a series of experiments using the REVERB challenge dataset.     

Self-generation of reward by logarithmic transformation of multiple sensor evaluations

Artificial Life and Robotics - Although the design of the reward function in reinforcement learning is important, it is difficult to design a system that can adapt to a variety of environments and...     

Revolving Vernier Mechanism Controls Size of Linear Homomultimer

A new kind of the Vernier mechanism that is able to control the size of linear assembly of DNA origami nanostructures is proposed. The mechanism is realized by mechanical design of DNA origami, which consists of a hollow cylinder and a rotatable shaft in it connected through the same scaffold. This nanostructure stacks with each other by the shape complementarity at its top and bottom surfaces of the cylinder, while the number of stacking is limited by twisting angle of the shaft. Experiments have shown that the size distribution of multimeric assembly of the origami depends on the twisting angle of the shaft; the average lengths of the multimer are decamer, hexamer, and tetramer for 0°, 10°, and 20° twist, respectively. In summary, it is possible to affect the number of polymerization by adjusting the precise shape and movability of a molecular structure.     

Optical implementation of visible gray-image morphology with the visual-area-coding technique

We present a novel scheme of visible gray-image morphology with the visual-area-coding technique (VACT). The VACT is a technique of digitized analog-optical computing in which data are converted into visible coded patterns and processed with the visible form. Because the achievable operations in the VACT are identical to those of mathematical morphology, mathematical morphology is adapted to gray-image morphology with the VACT. Computer simulation and optical experiments of the several operations in mathematical morphology verify the correctness of the proposed technique. The processing capacity of the proposed method is estimated in terms of the space-bandwidth product.     

Hypothesis testing in rank-size rule regression

This note examines testing methods for Paretoness in the framework of rank-size rule regression. Rank-size rule regression describes a relationship found in the analysis of various topics such as city population, words in texts, scale of companies and so on. In terms of city population, it is basically an empirical rule that log?(_S(i))$\log ?(S_{(i)})$ is approximately a linear function of log?(i)$\log ?(i)$ where _S(i)$S_{(i)}$ is the number of population of i  th largest city in a country. This is closely related to the so-called Zipf’s law. It is known that this kind of empirical observation is found when the city population is a random variable following a Pareto distribution. Thus one may be willing to test if city size has a Pareto distribution or not. Rosen and Resnick [K.T. Rosen, M. Resnick, The size distribution of cities: an explanation of the Pareto law and primacy, Journal of Urban Economics 8 (1980), 165–186] and Soo [K.T. Soo, Zipf’s law for cities: a cross country investigation, Regional Science and Urban Economics (35) 2005, 239–263] regress log?(_S(i))$\log ?(S_{(i)})$ on log?(i)$\log ?(i)$ and log?²(i)${\log ?}^2(i)$ and test the null of Paretoness by standard t-test for the latter regressor. It is found that t-statistics take large values and the Paretoness is rejected in many countries. We study the statistical properties of the t-statistic and show that it explodes asymptotically, in fact, by simulation and thus the t-test does not provide a reasonable testing procedure. We propose an alternative test statistic which seems to be asymptotically normally distributed. We also propose a test with the null hypothesis that the city size distribution is Pareto with exponent unity, which is a modification of the F-test.     

Intracellular recovery of gold by microbial reduction of AuCl4 ions using the anaerobic bacterium Shewanella algae

Microbial reduction and intracellular precipitation of gold was achieved at 25 °C and pH 7 by using the mesophilic anaerobic bacterium Shewanella algae with H₂ as the electron donor. The reductive precipitation of gold by S. algae was a fast process: 0.1–1 mol/m³ AuCl₄⁻ ions were completely reduced to insoluble gold within 30 min. The biogenic precipitates were crystalline gold nanoparticles of 10–20 nm present in the periplasmic space. The reducing power of S. algae at 3.2 × 10¹⁵ cells/m³ and 25 °C was comparable to that of aqueous citric acid solution (chemical reductant) at 20 mol/m³ and 50 °C. The intracellular recovery of gold is potentially attractive as an environmentally friendly alternative to conventional methods.     

The generic viewpoint assumption and planar bias

We show that generic viewpoint and lighting assumptions resolve standard visual ambiguities by biasing toward planar surfaces. Our model uses orthographic projection with a two-dimensional affine warp and Lambertian reflectance functions, including cast and attached shadows. We use uniform priors on nuisance variables such as viewpoint direction and the light source. Limitations of using uniform priors on nuisance variables are discussed.