Outstanding Paper Award Subcommittee of Kagaku Kogaku Ronbunshu has assessed the 66 papers published in volume 38 into 2012, and the editorial board finally selected the three papers for Kagaku Kogaku Ronbunshu Paper Awards of 2012; those are the papers on “Wet Chemical Preparation of Copper and Nickel Films for Multi-Layered Ceramic Capacitor,” “Enhancement of Fluid Mixing by Deformations of Streak Surface,” and “Development of a Circulating Fluidized Bed Reaction System Model for Estimation of FCC Catalyst Activity.”
The dielectric spectra of dimethyl ether (DME) + ethanol liquid mixture were measured at 293.2 K in the frequency range of 0.5–8.5 GHz. The dielectric spectra were correlated with single-phase Debye equation, and the static dielectric constants and the relaxation times for DME+ethanol mixtures were determined. These dielectric properties decreased with increasing DME concentration. The effective averaged angular Kirkwood correlation factors of DME+ethanol mixtures were calculated from the static dielectric constants. The concentration dependence of Kirkwood correlation factors showed concave shapes and has a minimum around 40 mol% of DME. This indicates that the hydrogen bonding between ethanol molecules is weakened with increasing DME composition in ethanol-rich region. In DME-rich region, on the other hand, dipolar orientation between DME molecules plays a dominant role of molecular orientation of DME + ethanol mixture.
The influences of an external magnetic field and a simple shear flow on rheological properties of colloidal dispersions composed of ferromagnetic rod-like particles were investigated by means of Brownian dynamics simulations. The ferromagnetic rod-like particles were modeled as a spherocylinders with magnetic charges on each hemisphere of the particles. The external magnetic field was applied along the direction normal to the shear plane. The net viscosity was decomposed into three components for detailed discussion: these three viscosity components arise from (a) the torque due to the magnetic particle-field interaction, and (b) the torque and (c) the force due to the interaction between particles. The main results were as follows. Under a relatively weak shear flow field, the viscosity increases significantly with increasing the magnetic particle-particle interaction. This is because chain-like clusters formed in the direction of the field induce a large resistance in a flow field. In contrast, when the flow field is dominant, the strong flow field collapses the chain-like clusters and the viscosity decreases.
Thermochromic liquid crystals (TLCs) are useful for understanding temperature fields, but their color changes occur over a narrow temperature range. This work aims to expand the applicable temperature range by concurrent use of a combination of liquid crystals with different temperature ranges, but because the correlation between color and temperature becomes complicated, a new deterministic technique is required. As a result of detailed color analysis, it was found that changing the concentration of TLCs in suspension resulted in a remarkable difference in chroma saturation and luminance and was effective for distinction of the TLCs. The color of each TLC was converted into temperature using the values of hue and chroma saturation entered into a database. By using this method, we were able to quantify temperature from the visualization image when two kinds of TLC were used. Also, although the angle of observation also influenced the observed color of TLC, bi-directional light irradiation into a test section minimized this problem.
The aerated power consumption was measured in mixing vessels equipped with dual impellers that combined a concave turbine and a Rushton turbine with a large ring sparger. When the ratio of sparger diameter to impeller diameter was larger than 1.3, no decrease was observed in aerated mixing power consumption.
Power consumption was measured for a rectangular eccentric mixing vessel with a propeller impeller. The power number of rectangular eccentric mixing vessels was constant regardless of the eccentric length, unlike the case of paddle and pitched paddle impellers. The power number for a cylindrical eccentric mixing vessel was correlated with the equations of propeller impeller by taking the number of baffles as unity and the baffle width as the eccentric length of the mixing shaft.
The demand for critical materials such as Li and Co increases with the demand for lithium ion batteries. Since there are no natural sources of Li and Co in Japan, it is desirable to recover these critical materials from batteries. Though LiCoO2 is mainly used as the cathode material, it could be replaced by cheaper materials such as Li(Co1/3Ni1/3Mn1/3)O2, LiMn2O4 and LiFePO4. Recovery of these valuable metals from lithium ion batteries by hydrometallurgical processes involves complex treatments including leaching, precipitation, and solvent extraction, together with costly steps to remove less valuable metals such as Fe and Al. In this study, the separation of Li+ and Co2+ from Li+/Fe3+/Al3+ and Co2+/Fe3+/Al3+ solutions was investigated with solvent extraction using the masking effect of chelating agents. On addition of chelating agents, it was found that Fe3+ and Al3+ formed water-soluble complexes, allowing Li+ and Co2+ to be selectively extracted in the organic layer. This effect depends on the stability of extractant-metal ion complexes and chelating agent-metal ion complexes. On addition of chelating agents, Fe3+ and Al3+ formed water-soluble complexes, allowing Li+ and Co2+ to be selectively extracted in the organic layer.
High C3H6 permselective silica hybrid membranes were successfully prepared by counter diffusion CVD. Propyltrimethoxysilane (PrTMOS), phenyltrimethoxysilane (PhTMOS) and hexyltrimethoxysilane (HTMOS) were employed as silica precursors. C3H6/C3H8 permeance ratio was 414 (C3H6 permeance 1.0 ×10-8 mol m-2 s-1 Pa-1) through the membrane deposited at 450°C for 5 min by using HTMOS as silica source. The optimum deposition temperature was 450°C for the HTMOS/O2 system to obtain a high C3H6 permselective membrane. HTMOS was selected from among the three silica precursors due to its high thermal stability. N2/SF6 permeance ratio decreased from 64 to 12 with increasing deposition period from 5 to 90 min. N2/SF6 permeance ratio showed the maximum at 2.2 × 105 through the membrane deposited at 450°C for 5 min.
Activated carbons (ACs) with different amounts of acidic functional groups and similar porous structure were prepared by oxidation with nitric acid, followed by outgassing at 500°C and 900°C. Desorption profiles of nitrobenzene (NB) were examined for NB pre-adsorbed ACs using differential thermogravimetric (DTG) analysis to inspect adsorption sites on ACs. Two peaks were observed in DTG profiles for ACs with acidic functional groups, whereas only one peak appeared for AC without carboxylic and lactonic groups. The DTG peaks observed around 100°C and 160°C could be assigned to desorption of NB adsorbed on π-electrons of graphene layer via π–π interactions, and on acidic functional groups via electro static interactions, respectively. This implies that π–π interactions are stronger than electro static interactions for NB adsorption.
Despite various studies on heat transfer by natural convection between long smooth vertical parallel plates heated at constant temperature or constant heat flux, no information is available on heat transfer by complicated natural convection between long heated plates accompanied by acceleration or deceleration downstream. Here, such heat transfer was considered experimentally and numerically. Heat transfer characteristics were investigated by generating natural convection between long smooth heated plates of which the channel cross-sectional area was changed in the downstream direction. At the same time, a mathematical model based on the physical phenomenon was built, and the experimental results and numerical computation were compared. As a result, it was shown that heat transfer by natural convection changes locally in accordance with the channel cross-sectional area, and that a unique phenomenon occurs that cannot be predicted from conventional knowledge of heat transfer by natural convection.
Heat transfer and fluid flow by turbulent natural convection were studied in a vertical enclosed rectangular container having a high aspect ratio and composed of heated and cooled plates maintained at constant temperature. The working fluids were air for low Rayleigh numbers, and are water and silicone oil of 1 cSt for high Rayleigh number. The velocity field in a vertical enclosed rectangular container was visualized and analyzed by particle image velocimetry (PIV) in order to examine the relation between heat transfer and fluid flow. The experimental results were found to be well correlated with the heat transfer correlation proposed previously.
In this study, non-thermal plasma-assisted combustion temperature was evaluated by spectroscopic measurement. First, temperature measurement by spectroscopy was compared with temperature measurement by use of a thermocouple. Temperature measurement by use of a thermocouple includes error due to thermal radiation, and this was corrected by calculation from material values of the combustion gas. In spectroscopic measurement, combustion temperature was calculated by Boltzmann plot method using CH radical emission. Next, it was shown that the temperatures measured by spectroscopy and by use of a thermocouple were in broad agreement. Finally, non-thermal plasma-assisted combustion temperature was measured by spectroscopy, and it was shown that the combustion was enhanced by non-thermal plasma.
For enhancing selectivity of multi-branched components and gasoline yield with a high octane number in FCC reactions, a low temperature method was proposed, and the appropriate zeolite for the conversion of olefins to multi-branched isomers and of paraffins to high octane compounds at a lower temperature than that of conventional FCC was investigated. For an olefin feedstock, a high conversion, the highest gasoline yield, and a high multi-branch yield were obtained at 350°C when SAPO-11 and silicalite-1 were used. ZSM-5 did not increase the amount of multi-branched components. For a paraffin feedstock, ZSM-5 showed a high conversion activity and produced high-octane compounds such as mono-branched and aromatic compounds, but SAPO-11 and silicalite-1 gave very low conversion. For feedstock containing olefins and paraffins, a zeolite possessing two different reactivities was thought necessary to enhance the multi-branch selectivity and the conversion of feedstock, and such an effect was verified by using the mixture of silicalite-1 and ZSM-5. The maximum gasoline yield and multi-branch concentration in the gasoline were obtained with a high octane number when a core/shell zeolite consisting of an inner layer of ZSM-5 and an external layer of silicalite-1 was employed at a low temperature. This core/shell zeolite was shown to have a new function in which complex FCC reactions proceeded at different acid sites with controlled molecular diffusion in the pores.
The authors have proposed a direct decomposition plant system for persistent waste oil by use of microwave-induced non-equilibrium plasma combustion. This study performed thermodynamic analysis of the proposed plant system as well as combustion experiments of the non-equilibrium plasma combustion. The combustion experiments showed that the low calorific value of exhaust gas from the combustion remarkably depended on oxygen ratio in the combustor, and the calorific value increased as the oxygen ratio decreased. The thermodynamic analysis revealed that the thermal efficiency and specific power of the proposed system were as high as 44.2% and 326.2 kJ/kg, respectively. These results suggested that the proposed system could supply all of the power required to operate the non-equilibrium plasma combustion.
The advance of distributed control systems in the chemical industry has made it possible to install many alarms cheaply and easily. While most alarms help operators detect an abnormality and identify its cause, some are unnecessary. A poor alarm system might cause alarm floods and nuisance alarms, which reduces the ability of operators to cope with plant abnormalities because critical alarms are buried under many unnecessary ones. Typical nuisance alarms are sequential alarms, which are a collection of many alarms that almost always occur simultaneously with specific time lags within a short time. We propose an analysis method of similarities between sequential alarms by using the Levenshtein distance, which is a string metric for measuring the difference between two sequences defined as the minimum number of edit costs needed to transform a string into another with edit operations of insertion, deletion, or substitution of a single character. The proposed method first converts the plant operation data, which consists of occurrence times and tag names of alarms and operations, into sequential alarm data. Then, similarities between all combinations of any two sequential alarms in the plant operation data are evaluated using the Levenshtein distance. The number of sequential alarms is effectively reduced by grouping them in accordance with the degree of similarity. The proposed method was applied to simulation data of an azeotropic distillation column. Results showed our method is able to group a lot of sequential alarms into small number of groups in accordance with the degree of similarity.
The immunostimulatory effects of an extract from dried nori (Porphyra yezoensis) were examined in vitro and in vivo. In vitro, the nori extract induced the production of interferon-γ (IFN-γ) in murine spleen cells, while it induced IFN-γ production and increased the cytotoxic activity for the human natural killer (NK) cells. In vivo, IFN-γ production was induced in the serum of normal mice by a single oral administration of nori extract, and survival was prolonged in allograft mouse models of melanoma after multiple oral administrations of nori extract. These results demonstrate that the nori extract had immunostimulatory effects in vitro and in vivo.
Separation of extracellular polysaccharides (TPS) by precipitation from culture broth of Polianthes tuberosa callus was studied. Addition of water-miscible solvents (ethanol, acetone and 2-propanol) together with inorganic salts was effective for forming TPS precipitates. In the presence of 2% NaCl, the percentage of TPS precipitated from solution with dielectric constant of about 50 was nearly 100%, regardless of organic solvents added. In solution with 50 vol% ethanol, the molar ratio of cations in inorganic salts (Na+ and Ca2+) to glucuronic acid groups in TPS had a positive correlation with the percentage of TPS precipitated. Xanthan gum, which also contains the glucuronic acid group, showed similar precipitation properties to TPS under the conditions examined. The proposed method was effective for purifying TPS at an acceptable level without significant denaturing of TPS.
Alcohol dehydrogenase ((R)-specific Parvibaculum lavamentivorans) immobilized on non-porous glass carriers with polyvinyl alcohol (PVA) was applied to the reduction of 1-phenylethanone in a gas-phase bioreactor. As a function of the amount of PVA added at enzyme immobilization, the enzyme activity showed a maximum at 10 mg/g-glass carriers that was 2-fold higher than that of the PVA-free system, while the enzyme stability remained almost constant. The reaction was optimized at a water activity in the feed gas phase of 0.9 and a reaction temperature of 303–313 K. The stereoselectivity of the immobilized enzyme was maintained a high level (enantiomeric excess of 99%) under all the experimental conditions.
In recent years, atmospheric plasma sources have been developed for industrial applications, because of its no need of vacuum pumping system or chambers and high-density plasma can be generated. However, conventional atmospheric plasma sources have a limitation of usable plasma gas species and a problem of thermal or electric discharge damage to targets. In our group, damage-free multi-gas plasma jet that solves these problems was developed. In this study, surface hydrophilization was tested using various kinds of plasma gases and effectiveness was investigated. Polyimide film was treated by oxygen, nitrogen and argon plasma in atmosphere. Nitrogen plasma was most effective and oxygen and argon plasmas follow it in order. Treated polyimide film surface by oxygen or nitrogen plasma was analyzed by XPS. It is observed that the percentage of C–C was decreased to 50% and C=O was increased to 40% with no difference between gas species. In plasma gas closed condition, nitrogen and oxygen plasma were most effective. Nitrogen and argon plasma had less hydrophilic effect in closed condition than that of in atmospheric condition.
A new concept was proposed for the manufacture of porous-solid-supported chemical heat storage material (PSM) that is applicable to solid base metal compounds and can maintain high reactivity and respond to volume changes. The pore structure characteristics of the carbonaceous porous-solid-supported Ca(OH)2 chemical heat storage material (Ca(OH)2-PSM) prepared based on this concept were evaluated, and it was found that the Ca(OH)2-PSM can be made into a high-density heat storage material with a maximum CaO/C weight ratio of 2.18, and the Ca(OH)2 is supported through thin layer dispersal primarily in pores of diameter 0.15 µm and 30 µm in the unsupported carbonaceous porous solid. The reactivity of this material was evaluated from its exothermic characteristics in repeated heat storage and release, and its long-term stability in form was evaluated based on optical observation after repeated heat storage and release. In evaluation of exothermic characteristics, the heat production temperature was measured in a hydration reaction under saturated steam conditions at 60°C in a packed-bed reactor simulating a chemical heat storage/chemical heat pump. The results showed that the maximum temperature rise was maintained after 15 repetitions, because agglomeration was inhibited due to the support of Ca(OH)2 in pores through thin layer dispersal. Optical observation showed that both the shape of the heat storage material particles and the Ca(OH)2 support state were maintained in their original condition after repeated hydration/dehydration reactions, and that secondary reactions do not occur. Thus it is evident that Ca(OH)2-PSM functions as a high-performance heat storage material for chemical heat storage.
Sewage sludge was treated by pyrolysis or by partial combustion, and the effect of treatment on the higher fatty acid content of the tar produced was examined. The energy recovery ratio in these treatments was also calculated by analyzing the gas, char and tar produced. Fatty acid was detected in the tar in high concentration, and 21.42 mg-fatty acid/g-sludge (phenol equivalent) was recovered after partial combustion at 973 K. Under the experimental conditons, 43% of higher fatty acid in dewatered sludge was recovered, of which palmitic acid was the major component of recovered tar.
The leaching properties of harmful trace elements were compared in four municipal incineration fly ashes: one from a typical medium-scale stoker furnace in Japan, and three from large-scale fluidized bed furnaces at three representative large cities in China. The Chinese ash samples had larger diameter, higher bulk density and different elemental contents from the Japanese ash. In column experiments with constant water head using 0.1 mol/L nitric acid solution, the Chinese ashes showed higher elution speed, while breakthrough, i.e., the rapid increase in the elution speed with decrease in pH due to elution of major and minor elements, was also observed, though within a shorter period than with the Japanese ash. The concentration changes of Pb, Cd, Cr and Mo were measured until steady elution was observed after breakthrough. The elution behavior of each element was similarly affected by changes of elution speed, especially by the phenomenon of breakthrough, despite large differences among the ash samples in elution rate and in the content and source of elements affecting their valences and other properties. Pb, the most abundant trace element in ashes, showed typical amphoteric metal properties. Leaching of Cd was found from neutral to acidic pH of the effluent. The elution rate of Cd from the Chinese ashes was much lower than that from the Japanese ash, which suggested the existence of mass transfer resistance between particles. Cr was leached out in greater amount than Pb at alkaline pH, but even under strongly acidic conditions its elution rate was low. Mo was eluted under alkaline conditions, but its concentration gradually decreased. The solubility data of hydroxides of elements under neutral and acidic conditions well explained the elution of Cd from neutral condition. They also suggest that the breakthrough phenomena are caused by the dissolution of Al and Fe(3+) ions at the column top, following deposition of their hydroxides by dissolution of alkaline elements, then their re-dissolution by acidification of solution.
Rare earth elements are present in more than 100 minerals, of which monazite, bastnaesite and xenotime are typical rare earth minerals. Rare earth elements have excellent chemical and physical properties for industrial use in functional materials such as phosphors, magnets, electronic components, abrasives and catalysts. China produces more than 90% of the world’s rare earths, and Chinese trends significantly influence the demand and price of rare earths. From the viewpoint of procurement, it is desirable to separate and recover rare earth elements from low-grade resources and wastes. Phosphate gypsum, a by-product of wet phosphoric acid manufacture, contains low concentrations of rare earth elements is one such resource. In this research, the separation and recovery of rare earth elements from phosphate gypsum were investigated. A series of recovery processes including washing of phosphate gypsum, leaching of the rare earth elements with sulfuric acid, adsorption and desorption of rare earth elements by using ion-exchange resin, and precipitation of rare earth oxalates was conducted. The separation of rare earth elements from Ca2+ simultaneously leached from phosphate gypsum was also investigated.
Chemical interface controlled dispersion and high-speed shearing water washing tests were carried out with highly radioactive contaminated soil of over 570,000 Bq/kg in Fukushima. In present experiment, ion plating Al2O3 ceramic coating was applied to SUS304 substrate material for prevention of radioactive contamination, and its erosion and decontamination performance were assessed. The following results were obtained. (1) Adhesion of fission product (FP) contained in refined soil particles was observed on the surface of SUS304 test coupons coated with 5 µm of Al2O3. In wipe-out tests, contaminated soil particles were easily removed from the surface of Al2O3 coated test coupon, whereas contaminated soil particles were tightly bound to the surface of uncoated SUS coupons. (2) The erosion rate of uncoated SUS coupons was estimated as 0.94 µm/h within 1 h of soil washing operation, after which no erosion was observed. Very slow erosion of 0.14 µm/h was observed in the case of Al2O3 coated test coupons during the soil washing process.