TEM analysis of high temperature annealed W nanostructure surfaces

Helium plasma irradiation and electron heating experiments were conducted using tungsten in the divertor simulator NAGDIS-II. Helium plasma irradiation to tungsten led to the formation of nanostructures on the surface, while the nanostructures were annihilated after the potential of the specimen was changed to positive for several 10 min so that electrons irradiated the sample without ion irradiation. The specimens were analyzed in detail by transmission electron microscope with the help of focused ion beam technique. It is revealed that the helium nano-bubbles still remained even after the nanostructures were disappeared from the surface. Porosity of the nanostructured tungsten was measured from the TEM images.     

Superstructure-based design and operation for biomass utilization networks

This paper is providing a design and evaluation methodology for biomass utilization networks (B-NETs) planning in local areas. The methodology is an effort to integrate various exertions of many researchers as well as stakeholders in the biomass field including process technologies, local area classification and renewable energy mechanisms to design and evaluate B-NETs. The proposed design methodology has three steps: classification, problem formulation and suggesting solution methods. The core part of planning the B-NETs utilization methodology is the superstructure that is a super class model for the processes of biomass utilization networks that has to be built for the local area. The biomass utilization superstructure (BUSS) relates the biomass resources to their products, available processes, and possible future processes of utilization in static manner. Although the local area BUSS is static in nature, it shows the decision makers what kinds of B-NETs are, or can be, available in their area. It is important to note that for each super class process there exists a number of elemental technologies, or what we call unit process (UP), that can perform the job under the same condition with different processing constraint. To support the design and operation process a technological information infrastructure (TII) needs to be built to work as an information pool and simulation tool. With the support of TII and the BUSS different scenarios can be synthesized, analyzed and compared. Scenarios development enables the designer to check processing alternatives as well as biomass promotion mechanisms that fit the concerns of various stakeholders. The results of the methodology application can be given in the form of suggestions of a specific network class(es) or scenarios that can be applied in a class of localities with the same characteristics. Following to methodology configuration, a proposal for optimization methods is discussed and a case study for comparing biomass network scenarios in mountainous city is introduced.     

Dendrite growth processes of silicon and germanium from highly undercooled melts

The crystal growth behavior of a semiconductor from a very highly undercooled melt is expected to be different from that of a metal. In the present experiment, highly pure undoped Si and Ge were undercooled by an electromagnetic levitation method, and their crystal growth velocities (V) were measured as a function of undercooling (ΔT). The value of V increased with ΔT, and V=26 m/s was observed at ΔT=260 K for Si. This result corresponds well with the predicted value based on the dendrite growth theory. The growth behaviors of Si and Ge were found to be thermally controlled in the measured range of undercooling. The microstructures of samples solidified from undercooled liquid were investigated, and the amount of dendrites immediately after recalescence increased with undercooling. The dendrite growth was also observed by a high-speed camera.     

Microscopic structure of athabasca oil sand

A refined structural model for in situ oil sands is proposed in terms of the mutual arrangement of sand grains, fines, water and bitumen. In the Athabasca deposit, the sand grains consist mainly of quartz and their packing is such that the porosity is about 35%. In rich oil sand, 10–15% of the pore space is occupied by connate water whereas the remainder is occupied by bitumen. For lower grade oil sands, a direct correlation exists between the water content and the amount of fines (particles smaller than 44 μm) and an inverse correlation exists between the bitumen content and the amount of fines. These relationships are successfully explained in terms of the irreducible water saturation in a porous medium and the double layer interaction between sand and bitumen surfaces.     

Application of the solid polymer electrolyte (SPE) method to organic electrochemistry—III. Kolbe type reactions on Pt-SPE

The feasibility of a solid polymer electrolyte (SPE) method for Kolbe type reactions was investigated by using Pt-SPE composed with Nafion 415 and platinum. The Kolbe reaction of acetic acid proceeded effectively on one side and both sides Pt-SPE composites. The lower current efficiency was observed on the latter than on the former. Neat acetic acid could also be electrolysed on both sides SPE though the cell voltage was fairly high.A methanolic solution of monomethyl adipate was electrolysed to give dimethyl sebacate on both sides Pt-SPE according to the Brown-Walker reaction. The current efficiency and the terminal voltage increased with the concentration of monomethyl adipate. Pt-SPE behaved as an active electrode of a high roughness factor, eg about 6, for the Kolbe reaction of acetate.     

Characteristics of the compact plasma device AIT‐PID with multicusp magnetic confinement

A unique plasma‐generation device called the “Aichi Institute of Technology‐Plasma Irradiation Device” has been developed for plasma–wall interaction (PWI) studies toward realization of a fusion reactor. It has power‐saving characteristics as well as compactness due to the employment of a multicusp magnetic field configuration instead of a strong axial magnetic field. Helium as well as argon plasmas are generated, showing an outstanding property of production of the hot‐electron component which can be controlled by changing the working gas pressure. Utilizing such outstanding properties, some typical studies on PWI are introduced. An azimuthally asymmetric confinement depending on the direction of magnetic field lines, particularly for energetic electrons, has been found. Some discussions on the physical mechanisms are given. IEEJ Trans 2011 DOI: 10.1002/tee.21801     

Flow structure of steam–water mixed spray

In this study, the flow structure of a steam–water mixed spray is studied both numerically and experimentally. The velocity and pressure profiles of single-phase flow are calculated using numerical methods. On the basis of the calculated flow fields, the droplet behavior is predicted by a one-way interaction model. This numerical analysis reveals that the droplets are accelerated even after they are sprayed from the nozzle. Experimentally, the mixed spray is observed using an ultra-high-speed video camera, and the velocity field is measured by using the oarticle image velocimetry (PIV) technique. Along with this PIV velocity field measurement, the velocities and diameters of droplets are measured by phase Doppler anemometry. Furthermore, the mixing process of steam and water and the atomization process of a liquid film are observed using a transparent nozzle. High-speed photography observations reveal that the flow inside the nozzle is annular flow and that most of the liquid film is atomized at the nozzle throat and nozzle outlet. Finally, the optimum mixing method for steam and water is determined.     

Influences of electroosmotic flows in nanopillar chips on DNA separation: Experimental results and numerical simulations

The various potential factors affecting the performance of nanopillar chips on DNA separation were investigated from the viewpoints of both numerical calculations and actual experiments. To yield higher performance and replace the conventional DNA separation techniques such as microchip electrophoresis, the phenomenon specific to the nanopillar chips should be deeply understood. In this paper, although various factors affecting the performance of the nanopillar chips are considered, we focused on the effect of electroosmotic flow, which is particularly noticeable in quartz-made nanopillar chips. High-resolution separation of DNA was realized when an electroosmotic flow was suppressed by simply using a higher concentration of buffer, but DNA separation failed in the presence of an electroosmotic flow. It was confirmed from the numerical simulations and the direct observations that the deformation of DNA band during the injection process was induced by electroosmotic flow and consequently led to a poor resolution.     

Effect of cooking on the antioxidant properties of coloured peppers

Pepper (Capsicum annum L.) has long been recognized as an excellent source of antioxidants, being rich in ascorbic acid and other phytochemicals. This study was conducted to investigate the effect of different cooking methods on the antioxidant properties of coloured peppers. Six varieties of peppers were subjected to different cooking methods, such as microwave heating, stir-frying and boiling in water, for 5 min individually. The cooked and raw peppers were analyzed for radical-scavenging activity (RSA) and total polyphenol content (TP) using 1,1-diphenyl-2-picrylhydrazyl–high-pressure liquid chromatography (DPPH)–HPLC and Folin-Ciocalteu methods, respectively. The samples were also evaluated for ascorbic acid content (AsA) by HPLC. Total carotenoid content was determined spectrophotometrically. Results suggest that there is no significant (P > 0.05) difference in RSA, TP, AsA and total carotenoid contents between the cooked and raw peppers when processed for 5 min. However, the cooked peppers show marked differences (P < 0.05) in the RSA, TP and AsA when cooked for 5 min in boiling water with further reduction observed after boiling for 30 min. This may be due to the leaching of antioxidant compounds from the pepper into the cooking water during the prolonged exposure to water and heat. Therefore, it is vital to use less water and cooking time and also to consume the water used for boiling so as to obtain the optimum benefits of bioactive compounds present in peppers. It is concluded that microwave heating and stir-frying without using water are more suitable cooking methods for pepper, to ensure the maximum retention of antioxidant molecules.