An electrochemical oxygen separator using an ion-exchange membrane as the electrolyte

An electrochemical oxygen separator based on oxygen reduction at an air cathode and oxygen evolution at an anode has been developed. The device features use of an ion-exchange membrane (Nafion 117) as the sole electrolyte and an air cathode mainly made of carbon.The anode was formed by chemically plating platinum (3.7 mgcm^–2) on one side of the Nafion 117 membrane. The air cathode was bonded to the other side of the membrane by spraying a slurry of graphitized furnace black loaded with platinum, followed by hot-pressing. The addition of a Nafion solution and a PTFE dispersion to the slurry was essential. The ultimate loading of platinum for the cathode was 0.2 mg cm^–2. An electrochemical oxygen separator with a working area of 100 cm² was constructed. When the separator was used as an oxygen concentrator it could be operated at 200 mA cm^–2 and produced 70.9 cm³ min^–1 of oxygen with a purity of 98.4%. When the separator was used as a circulation-type oxygen removal system it reduced the oxygen concentration of a 10-dm³ chamber to less than 0.02% within 70min. When the separator was used as a flow-through-type oxygen remover, air with an oxygen concentration of 0.02% was produced at 100 cm³ min^–1.     

Epoxy Networks Modified by a New Class of Oligomeric Silsesquioxanes Bearing Multiple Intramolecular Rings Formed through Si?O?C Bonds

Summary: A new class of silsesquioxane (SSO), containing species with two to nine Si atoms bearing multiple intramolecular rings formed through Si? O? C bonds, was synthesized as a glassy powder. It was characterized by UV‐MALDI‐TOF MS, ²⁹Si NMR and FT IR. Solutions containing different amounts of SSO in the diglycidyl ether of bisphenol A (DGEBA), were homopolymerized in the presence of (4‐dimethylamino)pyridine (DMAP) as initiator, leading to SSO‐modified epoxy networks. SSO species were covalently bonded to the epoxy network without any evidence of phase separation. The SSO addition provoked an increase in the elastic modulus in the glassy state explained by an increase in the cohesive energy density. The SSO addition gave also place to an increase in the intensity of tan δ and a decrease in both the glass transition temperature and the elastic modulus in the rubbery state. This was explained by a decrease in crosslink density associated with the flexibility of SSO structures. DMAP was much more effective than other usual initiators (like benzyldimethylamine, BDMA), in increasing the crosslink density of the resulting epoxy network. This led to high values of the glass transition temperature and the elastic modulus in the rubbery state.

Schematic representation of the chemical structure of the most significant species containing three Si atoms, present in the silsesquioxane.     

Toxicity of anionic detergents determined by Saccharomyces cerevisiae microarray analysis

Sodium n-dodecyl benzene sulfonate (LAS) and sodium dodecyl sulfate (SDS) are popular anionic detergents (surfactants) that are used worldwide and the toxicities of these chemicals have been characterized. We applied these chemicals in a DNA microarray bioassay and determined that the microarray data reflects previous findings and also provides some new information about anionic detergent toxicity. The mRNA expression profiles suggest that LAS and SDS cause damage to membranes and alterations in carbon metabolism, and induce the oxidative stress response. We also found that LAS and SDS induce the pleiotropic drug-resistance network, and that LAS and SDS may be pumped out of yeast cells by this network. Hierarchical clustering of the expression profiles showed that LAS and SDS cause similar features of toxicity and that the toxicity is similar to that of capsaicin but different from that of cadmium and mercury.     

Growth of homogeneous polycrystalline Si1-xGex and Mg2Si1-xGex for thermoelectric application

Homogeneous polycrystalline Si_1-xGe_x were grown using a Si(seed)/Ge/Si(feed) sandwich structure under the low temperature gradient less than 0.4 °C/mm. It was found that the composition of the Si_1-xGe_x was controlled by the growth temperature. The homogeneous Mg₂Si_1-xGe_x was synthesized by heat treatment of the homogeneous Si_1-xGe_x powders under Mg vapor. The Mg₂Si_1-xGe_x sample with the relative density of 95% was synthesized by spark plasma sintering technique. The resistivity and the Seebeck coefficient of the Si, Ge, Si_1-xGe_x and Mg₂Si_1-xGe_x samples were evaluated as a function of temperature. It indicated that Seebeck coefficients of the Si_1-xGe_x and Mg₂Si_1-xGe_x samples were higher than those of Si and Ge. Moreover, the Seebeck coefficient of Mg₂Si_0.7Ge_0.3 sample was higher than that of Mg₂Si_0.5Ge_0.5 and Si_0.5Ge_0.5 samples.     

An approach to the pursuit problem on a heterogeneous multiagent system using reinforcement learning

Cooperation among agents is important for multiagent systems having a shared goal. In this paper, an example of the pursuit problem is studied, in which four hunters collaborate to catch a target. A reinforcement learning algorithm is employed to model how the hunters acquire this cooperative behavior to achieve the task. In order to apply Q-learning, which is one way of reinforcement learning, two kinds of prediction are needed for each hunter agent. One is the location of the other hunter agents and target agent, and the other is the movement direction of the target agent at next time step t. In our treatment we extend the standard problem to systems with heterogeneous agents. One motivation for this is that the target agent and hunter agents have differing abilities. In addition, even though those hunter agents are homogeneous at the beginning of the problem, their abilities become heterogeneous in the learning process. Simulations of this pursuit problem were performed on a continuous action state space, the results of which are displayed, accompanied by a discussion of their outcomes’ dependence upon the initial locations of the hunters and the speeds of the hunters and a target.     

Analysis of adsorption equilibrium of volatile chlorinated organic compounds to dry soil

Adsorption is one of the main mechanisms of soil contamination by hazardous volatile chlorinated organic compounds. The adsorption equilibriums of six volatile organic chlorinated compounds to three dry soils were investigated using batch adsorption experiments. The adsorption equilibriums for the dry soils could be expressed by the Dubinin-Astakhov equation. The equation's parameters were analyzed with the characteristic values of the soils and compounds. No correlation between the values of the affinity coefficients, beta, and the molecular volume, Mv, was found. W(0) could be expressed by the functions of a pore volume of less than 10 nm, V(<10 nm), or the specific surface area, S. The adsorbed amount could be estimated using equations relating E(0), V(<10 nm) (or S), and beta. The predicted amounts agreed well with the measured data.     

Package images modulate flavor perception for orange juice

Most food packages contain images as well as textual information. While the influence of textual information on flavor evaluation has been well studied, the influence of images remains unexplored. Thus, this study investigated how the valence and congruency of images on juice packages influence flavor evaluations. There were 85 participants divided between four experimental conditions: (1) pleasant/congruent, with pleasant orange pictures; (2) unpleasant/congruent, with unpleasant orange pictures; (3) pleasant/incongruent, with pictures of pleasant non-food objects; and (4) unpleasant/incongruent, with pictures of unpleasant non-food objects. In each condition, pictures were attached to cups filled with juice. The participants rated the palatability, goodness of aroma, sweetness, bitterness, sourness, richness, freshness, and artificiality of 6 samples of the same juice. Juices presented with pleasant images were rated as more palatable and fresh. Juices presented with congruent images were rated with better aromas. This data shows that images on juice packages influence flavor evaluation.     

Response of osteoblast-like MG63 cells to TiO2 layer prepared by micro-arc oxidation and electric polarization

Micro-arc oxidation (MAO) is one of the useful surface modifications of titanium implants to improve bioactivity. Also, electric polarization treatment enhances bioactivity of calcium phosphate. The aim of this study was to evaluate the effect of the combination of two surface modifications, micro-arc oxidation (MAO) with electric polarization, on the behavior of osteoblast-like osteosarcoma MG63 cells. MAO-treated materials had a surface geometry that was favored by MG63 cells as determined using scanning electron microscopy and X-ray diffraction; additionally, electric polarization induced surface electric fields, which were measured using thermally stimulated depolarization currents. The results of assays to study cell–material interactions suggest that these two approaches could regulate cell attachment, spreading, proliferation, and differentiation without the addition of other reagents. This new surface modification processes produce materials with a good surface geometry, generate surface electric fields and enhance the osteopromotive ability of osteoblasts.     

Package images modulate flavors in memory: Incidental learning of fruit juice flavors

The effect of package images on incidental flavor memory for fruit juice was investigated. Ninety-two participants were allocated to three experimental conditions: (1) apple-label, (2) peach-label, and (3) control-label. In each condition, participants tasted a target flavor stimulus, a 1:1 mixture of 100% pure apple juice and 100% pure peach juice with pictures attached to the cups. Ten minutes later, participants were confronted with samples consisting of varying ratios of 100% peach to 100% apple juice, and were asked to rate their similarity to the target stimuli. Participants were also asked to rate how congruent the juice flavor and the image were at the initial tasting. Apple images modulated memories of the flavors of target stimuli: they shifted toward that of apples. This modulation occurred in participants who perceived the label and flavor as congruent. Peach images did not modulate memories, possibly because the subjects had significantly less experience of drinking peach juice than apple juice. These results reveal that flavor memory can be biased toward that of the image labels during initial tasting. However, memory bias depends on the perceived congruency between labels and flavors, and tasters’ prior experiences.     

Investigation of novel PCBM analogs containing thienyl groups for organic photovoltaic devices

Novel [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) analogs containing benzo[b]thiophene and thieno[3,2-b]thiophene were used as electron acceptors in bulk heterojunction thin layer organic photovoltaic devices. The solubility of the novel methanofullerenes in dichloromethane significantly varied, and es-TThCBM, which was 1.4 times as soluble as PCBM, exhibited maximum solubility. The morphology of the thin films prepared from the mixtures of these methanofullerenes with regioregular poly(3-hexylthiophene) (P3HT) was investigated by XRD, AFM, and UV–vis absorption spectroscopy. Devices containing the novel methanofullerenes exhibited nearly the same performance as those containing PCBM.