Quantitative high-resolution HAADF-STEM analysis of inversion boundaries in Sb(2)O(3)-doped zinc oxide

[Formula: see text] -doped ZnO crystals including inversion boundaries were investigated by high-resolution high-angle annular-dark field (HAADF) scanning transmission electron microscopy (STEM). The images were analysed with the aid of the image simulation based on Bethe method and also the retrieval processing using deconvolution. Utility of these two approaches for the HAADF-STEM analysis is discussed.     

Aquacultural approaches to recycling of dissolved nutrients in secondarily treated domestic wastewaters—III uptake of dissolved heavy metals by artificial food chains

We have studied the biological productivity, measured as biomass yields, of laboratory scale artificial food chains composed of sequential monocultures of suspended unicellular green algae (Scenedesmus), herbivorous cladoceran crustaceans (Daphnia magna), and herbivorous teleost fish (Hypophthalmichthys). These food chains were grown in minimally modified secondarily treated, chlorinated then dechlorinated, domestic waste waters. Successive stages in the chains were fed the organisms grown in the just preceding stages.Additions of 1 ppm ferrous sulfate and aeration with mixtures of air plus 5% carbon dioxide (buffered cultures) increased yields of Scenedesmus cultures by 52% above yields of air aerated, unsupplemented cultures (unbuffered cultures). Buffered cultures remained stable for long periods (1–2 weeks) and maintained good cell quality (no chlorosis; 90+% of cells present were Scenedesmus). Unbuffered, unsupplemented cultures soon became chlorotic, cells autoflocculated (which greatly reduced yields), and changes occurred in species composition. These latter cultures were unsuitable as food for cladocerans.Three production indices (conversion coefficients, specific production, and production/biomass ratios) showed that better growth occurred in cladoceran cultures fed buffered algal cultures as compared with unbuffered cultures. When fed unbuffered cultures cladocerans showed higher production indices when flocculated but unsettled cultures were used, as compared with supernates from flocculated, settled cultures.Attempts to grow the primarily herbivorous silver carp (Hypophthalmichthys molitrix) in a two-stage (buffered algae-fish) food chain failed. Ammonia toxicity may have been the cause of fish deaths.     

Synthesis of copolymer beads with various phenolic derivatives attached via different linkages and their antioxidation activity

Macroporous copolymer beads with various phenolic derivatives introduced via three types of linkages—amide, methylene, and ether—were prepared from chloromethyl styrene/tetra(ethylene glycol) dimethacrylate copolymer beads. The antioxidation activity of these phenolic copolymer beads was investigated by the measurement of the inhibition activity against the hydroperoxidation of 1,4-dioxane. The phenolic copolymer beads with the dihydroxybenzene moiety exhibited the highest antioxidation activity, and the antioxidation activity of methylene- or ether-linked phenolic copolymer beads was higher than that of amide-linked copolymer beads. Thus, the antioxidation activity of the phenolic copolymer beads was affected by not only the kinds of phenolic moieties attached but also the type of linkage group. In addition, the swelling of the copolymer beads in an organic solvent was greatly affected by the linkage type of the phenolic copolymer beads. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Solution-process coating of vertical ZnO nanowires with ferroelectrics

We have developed a modified misted deposition process by combining substrate and mist heating for the deposition of ferroelectrics on 3D nanostructures. Arrays of vertical ZnO nanowires, sputter coated with Pd bottom electrodes, are used as the substrate. Scanning electron microscopy investigations show that conformal coating of ferroelectric Pb(Zr,Ti)O(3) (PZT) with good step coverage is obtained at deposition temperatures above 140?°C. The substrate heating also eliminates the common 'bundling' problem of the nanowire arrays. On the basis of data on x-ray diffraction, energy dispersive x-ray spectroscopy, and P-E hysteresis of PZT films on flat substrates, we obtain the optimum substrate temperature window to be 180-220?°C, in terms of best step coverage and an evident ferroelectricity. This is a significant step towards the end-goal of fully integrated ZnO nanowires with ferroelectric capacitors, which may be useful for the light-emitting applications of ZnO.     

Electric-field-induced superconductivity in an insulator

Electric field control of charge carrier density has long been a key technology to tune the physical properties of condensed matter, exploring the modern semiconductor industry. One of the big challenges is to increase the maximum attainable carrier density so that we can induce superconductivity in field-effect-transistor geometry. However, such experiments have so far been limited to modulation of the critical temperature in originally conducting samples because of dielectric breakdown. Here we report electric-field-induced superconductivity in an insulator by using an electric-double-layer gating in an organic electrolyte. Sheet carrier density was enhanced from zero to 10(14) cm(-2) by applying a gate voltage of up to 3.5 V to a pristine SrTiO(3) single-crystal channel. A two-dimensional superconducting state emerged below a critical temperature of 0.4 K, comparable to the maximum value for chemically doped bulk crystals, indicating this method as promising for searching for unprecedented superconducting states.     

Biomanufacturing

Biomedical markets are large and rapidly growing owing to increasing demand for better healthcare services. The development of innovative biomedical systems can produce major breakthroughs in the healthcare industry, and advanced manufacturing technologies can propel such innovations. This paper summarises the field of biomanufacturing: namely, biospecific design constraints, biomechatronics, biofabrication, biodesign, and assembly. This paper presents state-of-the-art research, current problems, and future goals while providing fundamental knowledge required for entry into the biomedical industry. Biomanufacturing provides excellent opportunities for multi-disciplinary collaborations, both in academia and industry, and can lead to further advances in many engineering fields.     

Cyclotron production of the Ag, Pd, Rh radionuclides by Pd(p,x) nuclear processes

Production cross-sections of the ^105g+m,106mAg, ^100,101Pd, and ^{100g+m,101m,105g+m}Rh radionuclides through proton-induced reactions on natural palladium were measured up to 40 MeV by using a stacked-foil activation technique combined with high-resolution γ-ray spectrometry. The production cross-sections of ¹⁰¹Pd and ^{100g+m,105g+m}Rh radionuclides have been reported here for the first time from the ^natPd(p,x) nuclear processes. The present results are compared with the available literature values as well as the theoretical data calculated by the TALYS and the ALICE-IPPE computer codes. A quantitative comparison of the present results with the theoretical data has also been done with several deviation factor definitions. Optimal production pathways of the therapeutic ^105gRh radionuclide with minimal contamination using cyclotrons are discussed elaborately.     

Dynamic controlled milling process for bone machining

Optimal control of the machining process in orthopedic surgery can not only increase productivity but also ensure safety during tool usage. The authors have developed a technology for a force control system. The system has two modes of operation: the “air-cutting mode” and the “force control mode.” In the air-cutting mode, tool feed is scheduled by predicting the air and bone-cutting zones from the CAD/CAM system. In the force control mode, the software monitors the cutting force and the cutting temperature, and it controls the feed override according to the difference between the real and the desired cutting force. The software is installed on a robot controller, and its effectiveness is evaluated with a urethane bone.     

Partial hydrothermal oxidation of unsaturated high molecular weight carboxylic acids for enhancing the cold flow properties of biodiesel fuel

Biodiesel fuel has become more attractive recently because of its environmental benefits and the fact that it is a product made from renewable resources. However the less favorable cold flow properties or the low temperature operability of biodiesel fuel compared to conventional diesel is a major drawback limiting its use. The poor flow properties of biodiesel at cold temperatures are mainly due to biodiesel fuel being composed of long-chain fatty acids with an alcohol molecule attached. If the double bond of unsaturated fatty acids in these long-chain fatty acids could be ruptured selectively, then the cold flow properties of biodiesel fuel would be enhanced by reducing its viscosity.In this study, the selective hydrothermal oxidation of oleic acid, as a model compound of unsaturated high molecular weight carboxylic acids, was studied experimentally. The objective was to use this as a model to investigate whether the double bond of unsaturated fatty acids can be ruptured selectively by partial hydrothermal oxidation. Demonstration of this method could then be used to show the potential to improve the cold flow properties of biodiesel. Results showed that the amount of mono-carboxylic acids, aldehyde, di-carboxylic acids, and aldehyde-acids with a carbon number of 9 was significantly higher than other oxidative products. This suggests that the oxidative cleavage may principally occur at the double bond in hydrothermal conditions. The cloud and pour points for biodiesel fuel (B100) and B100 blend with a mixture of methyl esters or acetals were measured. These are the most important indicators for the cold flow properties of biodiesel fuel. The methyl esters or acetals used were made from the esterification of carboxylic acids or aldehydes by simulating the major oxidation products. These were obtained from the hydrothermal oxidation of oleic acid at different oxygen supply rates. Results showed that the cloud and pour points of the blend were significantly enhanced compared to those of B100.     

Operation strategy of residential centralized photovoltaic system in remote areas

Photovoltaic (PV) systems have found fairly wide application in remote isolated area. However, each individual PV system usually supplies energy only to one consumer. In such a case we have several consumers that each one of them uses a stand-alone PV system. This situation would expose such stand-alone systems to transient excessive loads larger than the power generated by the PVs, and then the battery is bound to discharge even during the day. For overcoming this problem, we suggest an autonomous centralized PV system, comprising one battery bank and plural subsystems connected to each other. From solar radiation data and load profiles, the performance of the PV centralized system is simulated by using a time step scheme. The advantages of this system are found to be the large charging rate of power, high efficiency, and low cost compared with conventional individual PV systems and hybrid systems. In addition, the economic study shows that the life cycle cost and the price of kilowatt hour generated in the centralized system is lower than that for the individual systems.