A generation method of artificial fluctuation data of wind power output considering smoothing effect

To use realistic wind power fluctuation data is important in simulating frequency change of power systems. It is well known that the smoothing effect must be taken into account when generating the artificial wind power output. Therefore, this paper proposed a new method to generate fluctuation waveform considering smoothing effect based on random number to fulfill the correlation among multiple sites and autoregression model. The effectiveness of the proposed method was tested by using practical wind speed data measured in Tohoku district.     

A design and simulation tool for ground source heat pump system using energy piles with large diameter

Calculation of the underground temperature resulting from heat injection/extraction into/from ground heat exchangers (GHEXs) with hourly variation is one of the most noteworthy challenges to address when simulating and designing a ground source heat pump (GSHP). In order to overcome this challenge, the authors introduce a method to calculate the underground temperature, by considering heat injection/extraction into/from GHEXs with hourly variation. The method applies the superposition of the infinite cylindrical source (ICS) solution and the infinite line source (ILS) solution to calculate the temperature change due to heat injection/extraction into/from the considered GHEX and other neighboring GHEXs, respectively. The calculation method also considers heat injection/extraction from GHEXs with different heat injection/extraction rates and is able to accommodate GHEXs with large diameters such as energy piles. The calculation method was evaluated by applying it to calculate the temperature variation of the heat carrier fluid in a GSHP system with energy piles.     

Multiresidue determination of quinolones in animal and fishery products by HPLC

A simple and rapid multiresidue method was developed for the determination of twelve quinolones (ciprofloxacin, danofloxacin, difloxacin, enrofloxacin, flumequine, marbofloxacin, nalidixic acid, norfloxacin, ofloxacin, orbifloxacin, oxolinic acid and sarafloxacin) in muscle, liver, chicken eggs, milk, prawn and rainbow trout.The quinolones were extracted from a sample with acetonitrile-water (95 : 5). A fifth part of the filtered extract was diluted with water to keep the acetonitrile ratio at ca. 60%, and passed through a C18 mini-column. The eluate was evaporated to dryness, and the residues were dissolved in methanol-water (30 : 70) for HPLC analysis.The quinolones were separated on a Inertsil ODS-3V column (4.6 mm i.d.x250 mm) with a gradient system of 0.1% phosphoric acid-acetonitrile as the mobile phase, with fluorescence detection.No interfering peak was found on the chromatograms of animal and fishery products, except for milk. The recoveries of the quinolones were over 60% from the animal and fishery products fortified at 0.1 microg/g, and the quantification limits of the quinolones were 0.005 microg/g. This proposed method was found to be effective and suitable for the screening of the quinolones in animal and fishery products.     

Photoinduced Formation of Small Gold Particles in Silica Gels

AuCl⁻₄ ions in sol-gel-derived silica gels (Au/silica gels) were photoreduced by ultraviolet light irradiation at room temperature. In the presence of ethylene glycol in the silica gels, small Au particles were effectively formed by the irradiation. When the storage temperature of the gels was increased in the dark after the irradiation, the surface plas-mon resonance absorption peak of the Au particles was shifted to longer wavelengths, indicating that the Au particles became large. At a storage temperature below 9°C, Au particles could not be observed in the silica gels. The apparent activation energy of Au particle formation was estimated to be 17. 3 kcal·tmol⁻¹.     

Analysis of upgraded solvent-refined coal (SRC) liquid products

Upgraded coal-derived liquids obtained from catalytic hydroprocessing of a 30–70(wt%) blend of SRC-1 with SRC-II have been studied by infrared and proton magnetic resonance spectroscopy, and gel permeation chromatography techniques. Compared with the feed blend, the upgraded liquids exhibit a lower C/H ratio and decreased aromatic, heteroatom and pentane-insoluble contents, along with decreased specific gravity and viscosity. The amount of hydrogen-bonded structure in the upgraded liquid decreases with increases in residence time and processing temperature. The pseudo-first-order disappearance of phenolic OH and total nitrogen during processing indicates a relative reactivity of 2:1 of hydroxyl oxygen removal to total nitrogen removal in the upgrading process. Conversion of pentaneinsolubles to soluble oil also follows a pseudo-first-order reaction; under mild processing conditions, the heteroatom functionalities play a dominant role in the ease and extent of this conversion. Higher temperatures increase thermal cracking and hydrocracking of the ring structure resulting in more conversion of asphaltene to oil. The linear dependence of the logarithm of viscosity on the content of heteroatoms and toluene-insolubles (TI) indicates the importance of molecular interactions involving polar functional groups in defining the viscosity of coal-derived liquid.     

Modification of bismaleimide resin by poly(propylene phthalate), poly(butylene phthalate) and related (co)polyesters

Aromatic polyesters were prepared and used to decrease the brittleness of the bismaleimide resin composed of 4,4′-bismaleimidediphenyl methane (BMI) and o,o′-diallyl bisphenol A (DBA) (Matrimid 5292 resin). The aromatic polyesters included poly(propylene phthalate) (PPP), poly(2,2-dimethylpropylene phthalate) (PDPP), poly(butylene phthalate) (PBP) and poly(butylene phthalate-co-butylene terephthalate) (50mol% terephthalate unit) (PBPT). The polyesters were effective modifiers for decreasing the brittleness of the bismaleimide resin. For example, inclusion of 20wt% PPP (MW 18700) led to 50% increase in the fracture toughness (K_IC) with retention of flexural properties and a slight loss of the glass transition temperature, compared with the mechanical and thermal properties of the unmodified cured bismaleimide resin. Micro-structures of the modified resins were examined by scanning electron microscopy and dynamic viscoelastic analysis. The thermal stability of the modified resins was slightly lower than that of the unmodified resin as determined by thermogravimetric analysis. The toughening mechanism is discussed in terms of the morphological and dynamic viscoelastic behaviour of the modified bismaleimide resin system. © 1998 SCI.     

Effect of static magnetic field on a thermal conductivity measurement of a molten droplet using an electromagnetic levitation technique

Recently, a novel method of measuring the thermophysical properties, particularly thermal conductivity, of high-temperature molten materials using the electromagnetic levitation technique has been developed by Kobatake et al. [H. Kobatake, H. Fukuyama, I. Minato, T. Tsukada, S. Awaji, Noncontact measurement of thermal conductivity of liquid silicon in a static magnetic field, Appl. Phys. Lett. 90 (2007) 094102]; this method is based on a periodic laser-heating method, and entails the superimposing of a static magnetic field to suppress convection in an electromagnetically levitated droplet. In this work, to confirm the fact that a static magnetic field really suppresses convection in a molten silicon droplet in an electromagnetic levitator, numerical simulations of convection in the droplet and periodic laser heating in the presence of convection have been carried out. Here, the convections driven by buoyancy force, thermocapillary force due to the temperature dependence of the surface tension on the melt surface, and electromagnetic force in the droplet were considered. As a result, it was found that applying a static magnetic field of 4 T can suppress convection in a molten silicon droplet enough to measure the real thermal conductivity of molten silicon.     

Preparation of Pt-loaded TiO2 nanofibers by electrospinning and their application for WGS reactions

Preparation of Pt-loaded TiO₂ nanofibers and their catalytic performance for water gas shift (WGS) reactions have been explained in this work. The Pt-loaded TiO₂ nanofibers were obtained by electrospinning poly-ethylene oxide (PEO) aqueous solutions containing Ti(OH)_n slurry and Pt nanoparticles at room temperature, followed by calcination at 773 K for 4 h. The calcined nanofibers were rougher than the nanofibers of PEO/Ti(OH)_n/Pt due to the PEO degradation and oxidation of Ti(OH)_n to TiO₂. Diameters of the Pt-loaded TiO₂ nanofibers ranged between 200 and 900 nm. Catalytic activity of the Pt-loaded TiO₂ nanofibers for water gas shift (WGS) reactions was evaluated and it was observed that their activity was 5–7 times higher than that of a bulk catalyst. Such improvement is attributed to the larger surface area of the nanofiber catalyst compared to that of the bulk catalyst. To the best of our knowledge, this is the first demonstration of a synthesis of Pt-loaded TiO₂ nanofibers from a Ti(OH)_n nanoparticle slurry using electrospinning and its application to WGS reactions.