A new, high precision, quick response pressure regulator for active control of pneumatic vibration isolation tables

Pressure regulators are important elements in pneumatic systems. Relief-type precision pressure regulators are commonly used to control the supply pressure to actively controlled pneumatic vibration isolators.Herein, a high precision, quick response pneumatic pressure regulator is proposed. This consists of an isothermal chamber, a servo valve, a pressure sensor, a quick response laminar flow sensor (QFS), and a pressure differential sensor (PD sensor) as developed by the authors. Slight changes of pressure in the chamber can be detected by the PD sensor and are fed back to the servo valve to maintain the pressure at a desired value. The performance of this regulator was confirmed experimentally in comparison with one available commercially. The regulator was then applied to the supply pressure regulation of an actively controlled pneumatic vibration isolation table. The superior performance of the regulator is clearly shown in the experimental results, especially in terms of avoiding effects from upstream or downstream disturbances.     

Preparation of large surface area nickel magnesium silicate and its catalytic activity for conversion of ethanol into buta-1,3-diene

The ternary oxide catalysts of nickel magnesium silicate with a large surface area (498–784m²/g) can be obtained by calcining a mixture of Ni(NO₃)₂, Mg(OH)₂ and SiO₂. The large surface area of the catalyst is attributed to its layer structure. The selectivity for buta-1,3-diene formation from ethanol on the catalysts was 90% or more and the yield of buta-1,3-diene was 53 mol%.     

Crystal structure and thermoelectric properties of chimney–ladder compounds in the Ru2Si3–Mn4Si7 pseudobinary system

Phase relationships of manganese-substituted ruthenium sesquisilicide alloys have been investigated by using X-ray powder diffraction and scanning and transmission electron microscopy. A series of chimney–ladder phases Ru_1?xMn_xSi_y (0.14 ? x ? 0.97, 1.584 ? y ? 1.741) are formed over a wide compositional range between Ru₂Si₃ and Mn₄Si₇. The compositions of these chimney–ladder compounds deviate slightly from the composition line connecting Ru₂Si₃ and Mn₄Si₇, which corresponds to the ideal composition line satisfying VEC (valence electron counting) = 14 rule. The occurrence of this compositional deviation is discussed in terms of the VEC rule and the atomic packing. The thermoelectric properties of the directionally solidified Ru_1?xMn_xSi_y alloys (0.55 ? x ? 0.90) have also been investigated as a function of the Mn content and temperature. The dimensionless figure of merit (ZT) for those alloys with a high Mn content (x ? 0.75) increased with the increase in Mn content. The ZT value for a crystal with x = 0.90 was as high as 0.76 at 874 K.     

PCDDs, PCDFs, and coplanar PCBs in albatross from the North Pacific and Southern Oceans: levels, patterns, and toxicological implications

Concentrations of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and coplanar polychlorinated biphenyls (coplanar PCBs) were determined in five albatross species collected from the North Pacific and Southern Oceans to assess the north-south differences in residue levels, accumulation patterns, and toxic potential. Black-footed and Laysan albatrosses from the North Pacific Ocean contained higher levels of PCDD/Fs and coplanar PCBs than albatrosses from the Southern Ocean, indicating that emission sources of these contaminants were predominant in the northern hemisphere. Residue levels in albatrosses from the remote North Pacific Ocean far from the point source of pollution were comparable to or higher than those in terrestrial and coastal birds from contaminated areas in developed nations, suggesting the specific exposure and accumulation of PCDD/Fs and coplanar PCBs in albatross. The long life span and ingestion of plastic resin pellets by albatrosses could be the plausible explanations for the elevated accumulation of persistent and lipophilic contaminants including PCDD/Fs and coplanar PCBs in these birds. Relative proportions of PCDFs and coplanar PCBs in albatross were higher than those observed in birds inhabiting terrestrial and coastal areas, suggesting that these toxic chemicals may have higher transportability by air and water than PCDDs. Congener patterns of PCDD/Fs in albatross showed less variability as compared to those in terrestrial species, indicating that contamination patterns of PCDD/Fs were similar within the open ocean environment. Contributions of PCDD/Fs to total TEQs in albatrosses from the open ocean were generally lower than those in terrestrial birds, suggesting different toxic potency of PCDD/Fs and coplanar PCBs on animals inhabiting open ocean and terrestrial environment. Whereas albatrosses from southern oceans retained lower TEQ concentrations, possible adverse effects of PCDD/Fs and coplanar PCBs to black-footed and Laysan albatrosses of the North Pacific Ocean may be suspected from TEQ levels.     

Binding affinity of tea catechins for HSA: Characterization by high‐performance affinity chromatography with immobilized albumin column

Catechins are the major polyphenols in green tea leaves. Recent studies have suggested that the catechins form complexes with HSA for transport in human blood, and their binding affinity for albumin is believed to modulate their bioavailability. In this study, the binding affinities of catechins and their analogs were evaluated and the relationship between the chemical structure of each catechin and its binding property were investigated. Comparing these catechins by HPLC analysis with the HSA column, we showed that galloylated catechins have higher binding affinities with HSA than non‐galloylated catechins. In addition, pyrogallol‐type catechins have a high affinity compared to catechol‐type catechins. Furthermore, the binding affinity of the catechin with 2,3‐trans structure was higher than those of the catechin with 2,3‐cis structure. The importance of the hydroxyl group on the galloyl group and B‐ring was confirmed using methylated catechins. These results indicate that the most important structural element contributing to HSA binding of tea catechins is the galloyl group, followed by the number of hydroxyl groups on the B‐ring and the galloyl group or the configuration at C‐2. Our findings provide fundamental information on the relationship between the chemical structure of tea catechins and its biological activity.     

Double-walled reformer tubes using high-temperature thermal storage of molten-salt/MgO composite for solar cavity-type reformer

Composite materials with alkali carbonate and magnesia have been examined for high-temperature thermal storage in solar tubular reformers. The concept of a double-walled reactor tube involves packing a molten-salt/ceramic composite material into the annular region between internal catalyst tube and exterior solar-absorber wall. In this paper, the shape and interior structure of the reactor tube are newly designed for use in solar cavity-type reformers using straight reactor tubes. Na₂CO₃, K₂CO₃, and Li₂CO₃ composite materials with magnesia were tested as thermal storage media for CO₂ reforming of methane during cooling mode of the reactor tube at a laboratory scale. The efficiency of Na₂CO₃/MgO composite with various MgO contents was also estimated. Composite materials of Na₂CO₃ 80–90 wt% and MgO 20–10 wt% were successfully delayed the cooling of the catalyst bed and sustained methane conversion at >90%. A solar cavity-type reformer consisting of multiple straight reactor tubes is expected to enable stable operation of the solar reforming process under fluctuating solar insolation during cloud passage.     

A Wind Power Forecasting Method and Its Confidence Interval Estimation

This paper describes a wind power forecasting method and its confidence interval estimation. Recently, flat control of wind power generators using various batteries has been required. In flat control, accurate wind power forecasts and their error confidence intervals are needed. In this paper, wind speed forecasts are calculated by regression models using Grid Point Value (GPV) weather forecasts. The forecasts are adjusted by fuzzy inference using the latest errors. The wind power forecasts are translated from the wind speed forecasts using two power curves. The power curves are selected or combined by fuzzy inference depending on the wind direction. The error confidence interval models are generated for each forecasting target time. Each confidence interval is combined by the other fuzzy inference. The proposed methods were applied to actual wind power generators, and it was found that the forecasting errors were smaller than in the conventional methods. Almost all of the forecasts can be within the error confidence intervals estimated by the proposed methods. The results show the effectiveness of the proposed methods. © 2013 Wiley Periodicals, Inc. Electr Eng Jpn, 186(2): 52–60, 2014; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.22326     

Low temperature Si-DLC coatings on fluoro rubber by a bipolar pulse type PBII system

Diamond-like carbon (DLC) films have been attractive materials because of their excellent mechanical properties such as high hardness, low friction coefficient, high wear resistance and more. In order to spread the application of the DLC coatings for polymer materials, it is necessary to make the temperature go down during the coating process.Our group has been studying DLC coatings on several materials with bipolar pulse type PBII (plasma based ion implantation) systems, which consist of positive and negative (or bipolar) pulse generators and a timing controller. Recently we have introduced a new bipolar pulse generator, whose slew-rate is several times larger than that of previous generators, and a controller which can make a very short pulse less than 1 μs. Using the pulse generator and controller, we have tried to make Si incorporated DLC (Si-DLC) coatings on fluoro rubber, which is widely used in many industries, at low temperature.Using the new pulse generator and controller, we can make very short width positive pulse of about 1 μs, and reduce the temperature during Si-DLC coating to about 30 K. The lower temperature makes fewer folds on the sample surface. By using optical indentation microscope system, Meyer hardness (H_M) of uncoated and Si-DLC coated fluoro rubber was obtained and the value of H_M for Si-DLC coated rubber is about 1.4 times larger than that of uncoated rubber. Coefficient of friction of Si-DLC coated rubber was 0.2 to 0.25 and drastically decreased from 1.3 to 1.9 of uncoated rubber. Wear of uncoated fluoro rubber is apparent, however, wear of Si-DLC coated rubber cannot be observed, except for the creep effect of fluoro rubber substrate. The counter SUJ2 ball surfaces also showed almost no wear. Si-DLC coating can make the tribological property of fluoro rubber to low friction and less wear. Si-DLC coatings are very useful in many applications.     

A macroscopic cross-section model for BWR pin-by-pin core analysis

A macroscopic cross-section model used in boiling water reactor (BWR) pin-by-pin core analysis is studied. In the pin-by-pin core calculation method, pin-cell averaged cross sections are calculated for many combinations of core state and depletion history variables and are tabulated prior to core calculations. Variations of cross sections in a core simulator are caused by two different phenomena (i.e. instantaneous and history effects). We treat them through the core state variables and the exposure-averaged core state variables, respectively. Furthermore, the cross-term effect among the core state and the depletion history variables is considered. In order to confirm the calculation accuracy and discuss the treatment of the cross-term effect, the k-infinity and the pin-by-pin fission rate distributions in a single fuel assembly geometry are compared. Some cross-term effects could be negligible since the impacts of them are sufficiently small. However, the cross-term effects among the control rod history (or the void history) and other variables have large impacts; thus, the consideration of them is crucial. The present macroscopic cross-section model, which considers such dominant cross-term effects, well reproduces the reference results and can be a candidate in practical applications for BWR pin-by-pin core analysis on the normal operations.