Dietary CLA and DHA modify skin properties in mice

This study investigated the influence of PUFA on the properties of mouse skin. Mice (3 wk old) were given free access to oils high in linoleic acid, CLA, or DHA for 4 wk. At the end of the experiment, their skins were compared by both biochemical and histological methods. No significant differences in lipid and collagen contents were detected among treatments, although the FA composition in the skin was altered depending upon the FA composition of the supplemented oils. Electron microscopy revealed that the subcutaneous tissue layers in the CLA and DHA groups were significantly thinner than that in the high linoleic acid group, whereas no differences in the thickness of dermis layers were observed among the three groups. These results suggest that skin properties in mice are readily modified by dietary FA sources within 4 wk of dietary oil supplementation.     

Three-Dimensional Numerical Simulation of Helically Propagating Combustion Waves

In the present paper, by using a mathematical model for self-propagating high-temperature synthesis, we reveal the three-dimensional structure of so-called spin combustion wave on the inside of cylindrical sample. It is shown that an isothermal surface of regular spin combustion wave has some wings of which number is the same as that of reaction spots on the cylindrical surface and that the isothermal surface with helical wings rotates down with time. Because of this propagating pattern, in this paper, we adopt the more suitable term helical wave. We also obtain the following existence conditions of a helical wave: If physical parameters are set so that a pulsating wave exists stably for the one-dimensional problem, then a helical wave takes the place of a pulsating wave when the radius of cylindrical sample becomes large.     

Novel structure of GaAs-based interdigital-gated HEMT plasma devices for solid-state THz wave amplifier

Theoretical analysis of potential distribution in the interdigital-gated high electron mobility transistor (HEMT) plasma wave device was carried out. The dc I–V characteristics of capacitively coupled interdigital structure showed that uniformity of electric field under the interdigital gates was improved compared to the dc-connected interdigital gate structure. Admittance measurements of capacitively coupled interdigital gate structure in the microwave region of 10–40 GHz showed the conductance modulation by drain–source voltage. These results indicate the existence of plasma wave interactions.     

Informative patches sampling for image classification by utilizing bottom-up and top-down information

In image classification based on bag of visual words framework, image patches used for creating image representations affect the classification performance significantly. However, currently, patches are sampled mainly based on processing low-level image information or just extracted regularly or randomly. These methods are not effective, because patches extracted through these approaches are not necessarily discriminative for image categorization. In this paper, we propose to utilize both bottom-up information through processing low-level image information and top-down information through exploring statistical properties of training image grids to extract image patches. In the proposed work, an input image is divided into regular grids, each of which is evaluated based on its bottom-up information and/or top-down information. Subsequently, every grid is assigned a saliency value based on its evaluation result, so that a saliency map can be created for the image. Finally, patch sampling from the input image is performed on the basis of the obtained saliency map. Furthermore, we propose a method to fuse these two kinds of information. The proposed methods are evaluated on both object categories and scene categories. Experiment results demonstrate their effectiveness.     

Facile ion-exchanged synthesis of Sn incorporated potassium titanate nanoribbons and their visible-light-responded photocatalytic activity

Sn²⁺-incorporated potassium titanate (K₂Ti₆O₁₃) nanoribbons were prepared by a facile acid-free ion-exchanged method in a dehydrated methanol solution at room temperature. XRD patterns suggested that K₂Ti₆O₁₃ (KTO) and Sn²⁺-incorporated KTO (SKTO) are well crystallized with monoclinic phase structures. The mole ratio of incorporated Sn²⁺ to K⁺ in SKTO was estimated to be 2. X-ray photoelectron spectrum showed that the Sn species of SKTO consisted of 90% of Sn²⁺ and 10% of Sn⁴⁺, suggesting that part of Sn²⁺ was oxidized to Sn⁴⁺ in the incorporation process. The band gap of SKTO was 0.7 eV narrower than that of KTO, which was derived from lift of the top of the valence band due to the hybridization of Sn5s and O2p orbitals. The SKTO nanoribbons showed remarkable photocatalytic activities for H₂ evolution and rhodamine B degradation under visible light irradiation (λ ≥ 420 nm). The photocatalytic mechanism and durability were studied in detail. The advantage of this acid-free ion-exchange method is ease of ion-exchange of K⁺ with H⁺ and maintenance of the integrity of the 1D nanoribbon structures. This method can be applied to preparation of other Sn²⁺-incorporated compounds with special nanostructures.     

Pore-scale visualization of gas trapping in porous media by X-ray CT scanning

Entrapment of the non-wetting phase in porous media has been observed in a variety of fields such as petroleum engineering, geological storage of carbon dioxide, and remediation of ground water. We investigated gas trapping in porous media from a microscopic point of view. High-resolution, three-dimensional images of pore structure and trapped gas bubbles in Berea sandstones were obtained using a micro-focused X-ray CT scanner. We used vertical and horizontal Berea sandstone cores, 8 mm in diameter and 15 mm long. Based on the three-dimensional image analysis, the statistical distribution of the trapped gas volume was estimated. Trapped bubbles have a pore-network scale size and distribute over several pores. In the case of the vertical core, the porosity fluctuates along the flow direction due to the layered structure. The residual gas saturation also fluctuates with porosity along the flow direction. The higher gas saturation in porous layers at the end of gas injection results in a higher trapped gas saturation compared to dense layers. On the other hand, in dense layers the gas saturation at the end of gas injection is almost the same as residual gas saturation. Therefore, most of the gas injected into the dense layers would be trapped. In the case of the horizontal core, the gas saturation at the irreducible water condition is lower than that for the vertical core, because the injected gas selectively passes through the more permeable layers. However, the residual gas saturation is 29.2% for the horizontal core, which is comparable with that for the vertical core (30.9%). Finally, the effect of capillary number on stability of trapped gas bubbles has been estimated. Trapped gas bubbles are stable against the increased flow rate up to a capillary number of 1.0×10^?5.     

On the influence of residual stresses on the fracture behavior of a structural steel in the KIc temperature range

The increase with increasing temperature of K_Ic, measured with 2CT and 1'CT specimens, from about 10³N mm at 77 K to about 2.10³ N mm at about 170 K is attributed to the increasing proportion of dimple to cleavage fracture as revealed by scanning electron microscope investigation.

The specimens were prestrained to different partial scale yielding states by the same kind of loading, performed at 298 K, as in the later K_Ictests, performed at 77 K. After pretension K_Ic = K^*_Ic is increased by a maximum amount of about half of the value K⁰_Icof nonprestrained specimens, after precompression it is reduced by the same amount if this value is evaluated from the load at which a pop-in occurs. The value K_Ic = K^**_Ic for the final fracture lies between K^*_Ic and K⁰_Ic. These results are interpretated in terms of the residual stress states due to prestraining.     

Effect of heat treatment on precipitation behaviour and high temperature strength in a wrought Co-base superalloy

The effects of solution and ageing temperatures on the grain boundary reaction as well as on matrix precipitation in the interior of the grains were investigated using wrought Co-base superalloy HS-21. The grain boundary reaction occurred during furnace-cooling after solution-heating. The phase that precipitated in the grain boundary reactions nodule was M₂₃C₆ carbide. It also occurred during ageing after solution treatment, but the extent of it was considerably influenced by cooling procedure after solution heating. The activation energy of the grain boundary reaction was 244 kJ mol^–1 for the early stage of the grain boundary reaction in HS-21 alloy, and was considered to be the activation energy of grain boundary diffusion of chromium. The extent of the matrix precipitation that occurred during ageing was also influenced by the cooling procedure. Creep rupture tests were carried out at 1088 K in air. An excellent combination of long rupture life and large ductility was attained on a specimen, which involved both the grain boundary reaction nodules (about 7% in area fraction) and the matrix precipitates. The improvement of creep rupture properties results from the retardation of brittle intergranular fracture, which is achieved by grain boundary serration owing to the grain boundary reaction and by the increase of strength in the interior of grain due to the matrix precipitation.     

A new recovery process of carbon dioxide from alkaline carbonate solution via electrodialysis

Bipolar membrane electrodialysis is applied to CO₂ recovery from alkaline carbonate solution. CO₂ in flue gas is captured by an alkaline hydroxide absorbing solution to form an alkaline carbonate solution. The captured CO₂ is recovered from the alkaline carbonate solution via bipolar membrane electrodialysis, and the alkaline solution is regenerated simultaneously. To reduce the power requirement for CO₂ recovery, this study considers optimal design and operation. Three membrane arrangements were compared, and the results indicate the membrane arrangement comprising a bipolar membrane and cation exchange membrane is the most energy saving. With further optimization of operation conditions, the minimum power requirement for CO₂ recovery was reduced to 2.1 MJ/kg‐CO₂ (or 2.1 GJ/t‐CO₂). © 2009 American Institute of Chemical Engineers AIChE J, 2009