Formation of needle-like titanium oxynitride particles through nitridation of hydrated titanates

The process of nitridation of hydrated titanate wires was examined by thermal gravimetric (TG) analysis in an NH₃/Ar (50/50 vol.%) gas mixture, X-ray diffraction (XRD) measurement, field emission scanning electron microscope (FE-SEM) and transmission electron microscope (TEM) observations and X-ray photoelectron spectroscopic (XPS) analysis. The nitridation of the hydrated titanate nanowires was accompanied by a two-stage weight loss. In the first stage, occurring in the temperature range of 50-400 °C, the hydrated titanate wires changed to anatase-type TiO₂ nanoparticles with the releasing of H₂O molecules. In the second stage, occurring in the temperature range of 700-1000 °C, the TiO₂ nanoparticles were converted to rock-salt-type titanium oxynitride (TiN_xO_y) nanoparticles. Subsequently, the TiN_xO_y nanoparticles were sintered each other at around 1000 °C. Under a gas flow of 100% NH₃, the hydrated titanate wires were completely changed to TiN_xO_y particles at a temperature greater than 950 °C, which was maintained for 2 h. It is possible to fabricate needle-like TiN_xO_y particles by selecting thick hydrated titanate wires as the starting materials.     

Hydrogen enhanced crack propagation of SCM440H low-alloy steel under long-term varying load

Crack propagation behavior of SCM440H low-alloy steel enhanced by absorbed hydrogen is investigated. Six materials tempered at different temperatures are used. Effects of stress ratio, loading frequency, hold time and material hardness on the crack propagation rate are examined under long-term varying load. Tests have been performed under continuous hydrogen charging, in which the crack tip has been isolated from the electrolyte and kept dry. An acceleration of crack propagation rate about six times compared to the uncharged material is found in all materials. In addition to this, however, an unexpected acceleration of crack propagation up to 1000 times is experienced under certain conditions. In materials with Vickers hardness higher than 280 tested at low frequency, the above marked acceleration is experienced. The crack surface morphology is quasi-cleavage. This critical hardness (HV = 280) is a little lower than the usually accepted critical hardness for delayed failure (HV = 350). In material with Vickers hardness lower than 268, however, such a marked acceleration is not experienced.     

Experiments on a tokamak device with force‐balanced coils

High field is very favorable for magnetically confined fusion devices such as a tokamak, but the electromagnetic force derived from the field becomes a fatal problem. In particular, the largest in‐plane centering force hinders toroidal field coils from operating at higher fields. Although variable‐pitch multihelical coils, which we term force‐balanced coils (FBCs), by which this force is drastically reduced, were proposed for the coil system of tokamaks, there had been no actual tokamak device with FBCs. Therefore, Todoroki‐1, a small tokamak device with FBCs has been manufactured and experiments started. In this paper, the structure of Todoroki‐1 is indicated, and the stray magnetic field and centering force on FBCs are investigated. The plasmas have been generated in the device, and attempts at better plasmas are beginning. © 1999 Scripta Technica, Electr Eng Jpn, 130(3): 19–29, 2000     

Application of a force‐balanced coil to a tokamak device

High field is very favorable for magnetically confined fusion devices such as a tokamak, but electromagnetic force derived from the field becomes a fatal problem. In particular, the largest in‐plane centering force hinders toroidal field coils from operating at higher fields. Variable pitch multihelical coils, which we term force‐balanced coils (FBCs), by which this force is drastically reduced, are proposed for the coil system of tokamaks. FBCs can also provide poloidal flux swing for plasma breakdown and current induction during the ramp‐up phase of the coil current. In this paper, we indicate how to design FBCs for tokamaks. The fusion reactor‐size FBCs are designed and compared with that of the conventional toroidal field coil system. © 1999 Scripta Technica, Electr Eng Jpn, 130(3): 39–48, 2000     

Microbial Conversion of Arachidonic Acid to Arachidonyl Alcohol by a New <Emphasis Type="Italic">Acinetobacter</Emphasis> Species

Arachidonyl alcohol rarely occurs in natural oils. It can be used as a substrate for production of several ether lipids possessing beneficial functions. Although arachidonyl alcohol has been produced on a laboratory scale by the chemical reduction of arachidonic acid, it will be difficult to scale up this process for industrial application. The aim of this study was to develop a new bioprocess for converting arachidonic acid to arachidonyl alcohol. Screening was conducted using 11 wax ester- (esters of fatty acids and fatty alcohols) producing strains reported in our previous study, and a single-cell oil containing arachidonic acid. A new strain, Acinetobacter species N-476-2, most effectively converted arachidonic acid to arachidonyl alcohol, which accumulated inside the cells as a wax ester. GC–MS, FT–IR, and NMR analyses showed that this strain reduced the carboxyl group of 5-cis,8-cis,11-cis,14-cis-arachidonic acid to a hydroxyl group without altering the position or configuration of the double bonds; the product was identified as 5-cis,8-cis,11-cis,14-cis-arachidonyl alcohol. A time-course study of cultivation showed that the amount of arachidonyl alcohol produced by the strain after 4 days was 2.2 mg/mL culture. The bioprocess using Acinetobacter sp. N-476-2 can be applied to the large-scale production of arachidonyl alcohol.     

Molecular weight dependency of refractive index increment of polystyrene determined by uniform oligomers

Molecular weight dependency of a specific UV absorption coefficient of polystyrene in solution was determined by supercritical fluid chromatography applied to equimolar and equimass mixtures of uniform polystyrenes whose degree of polymerization was n = 1 to 40. From the ratio between the response from a UV detector and that from a refractometer, we determined the refractive index increment dn/dc as a function of molecular weight for polystyrene in tetrahydrofuran at the wavelength λ = 633 nm. We found that dn/dc is well expressed as a linear function of the reciprocal of molecular weight for uniform polystyrenes. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1101–1106, 2004     

Production of structured TAG rich in 1,3-dicapryloyl-2-γ-linolenoyl glycerol from borage oil

γ-Linolenic acid (GLA) has the physiological functions of modulating immune and inflammatory responses. We produced structured TAG rich in 1,3-dicapryloyl-2-γ-linolenoyl glycerol (CGC) from GLA-rich oil (GLA45 oil; GLA content, 45.4 wt%), which was prepared by hydrolysis of borage oil with Candida rugosa lipase having weak activity on GLA. A mixture of GLA45 oil/caprylic acid (CA) (1∶2, w/w) was continuously fed into a fixed-bed bioreactor (18×180 mm) packed with 15 g immobilized Rhizopus oryzae lipase at 30°C, and a flow rate of 4 g/h. The acidolysis proceeded efficiently, and a significant decrease of lipase activity was not observed in full-time operation for 1 mon. GLA45 oil contained 10.2 mol% MAG and 27.2 mol% DAG. However, the reaction converted the partial acylglycerols to structured TAG and tricaprylin and produced 44.5 mol% CGC based on the content of total acylglycerols. Not only FFA in the reaction mixture but also part of the tricaprylin and partial acylglycerols were removed by molecular distillation. The distillation resulted in an increase of the CGC content in the purified product to 52.6 mol%. The results showed that CGC-rich structured TAG can efficiently be produced by a two-step process comprising selective hydrolysis of borage oil using C. rugosa lipase (first step) and acidolysis of the resulting GLA-rich oil with CA using immobilized R. oryzae lipase (second step).     

From knowledge-based potentials to combinatorial lead design in silico

Computational methods are becoming increasingly used in the drug discovery process. In this Account, we review a novel computational method for lead discovery. This method, called CombiSMoG for "combinatorial small molecule growth", is based on two components: a fast and accurate knowledge-based scoring function used to predict binding affinities of protein-ligand complexes, and a Monte Carlo combinatorial growth algorithm that generates large numbers of low-free-energy ligands in the binding site of a protein. We illustrate the advantages of the method by describing its application in the design of picomolar inhibitors for human carbonic anhydrase.     

Numerical Simulation and Experiment on the Transport of Fine Particles in a Ventilated Room

ABSTRACT

The change in concentration distribution of particulate contaminants emitted in a room was studied experimentally and theoretically to investigate whether the transport of contaminants in a room with a source of particles can be predicted by numerical simulation. Tracer contaminants, monodisperse latex particles, were introduced into a 3.3 m ×2.7 m ×2 m room with clean air for a given time, and the change in the contaminant concentrations with time was measured at various positions in the room. Calculations of the spatial and temporal distributions in the gas velocity and contaminant concentration were performed to predict the concentration change, with the Navier-Stokes and convection-diffusion equations solved numerically. The experimental results showed that the concentration distribution depends on the position of introduction of the contaminants. It was also indicated that the contaminants introduced near the room floor diffuse more than predicted. However, the calculated concentrations agreed almost quantitatively with the measured results, except near the floor and walls. The change in the concentration with time and the dependence of the concentration distribution on the position of the particle source were well reproduced by the calculation.     

Design-of-use and design-in-use by customers in differentiating value creation

Customer use processes should be more focused in both products and services for better customer satisfaction. The paper proposes a model of value creation by encouraging two types of customer activities pertaining use processes: design-of-use (configuration design before use) and design-in-use (adaptive design during use). By retrieving and utilizing data on usage generated by customers, different classes of value creation (i.e., providing value, adaptive value, and co-creative value) may work together. The proposed model is exemplified by a study on tourism involving a travel agency, independent travelers, and a community of travelers.