Hiroshi Satone

Bicellar mixtures containing diacetylene molecules, such as diynoic acids, can be used as parent materials for functional membranes. A bicellar mixture consisting of a diynoic acid-10,12-tricosadiynoic acid (TCDA)-, a phospholipid-1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC)-, and a detergent-3-[(3-cholamidopropyl) dimethylammonio]-2-hydroxypropanesulfonate (CHAPSO)-was evaluated for its morphology and packing of TCDA molecules in its bicellar mixture. A TCDA/DMPC vesicle was prepared at different molar ratios, TCDA/DMPC = 2/8, 5/5, and 8/2; a TCDA/DMPC/CHAPSO bicellar mixture was prepared by mixing a CHAPSO solution with a TCDA/DMPC vesicle solution as a detergent at different composition ratios, x TCDA/DMPC = [TCDA/DMPC]/([TCDA/DMPC]+[CHAPSO]), of 1.0, 0.70, 0.50, and 0.30. A DMPC molecule formed a bilayer membrane structure and was used to suppress its precipitation. The packing density of the TCDA/DMPC/CHAPSO bicellar mixtures was increased by mixing a CHAPSO molecule in x TCDA/DMPC = 1.0 to 0.70 or 0.50. A TEM image of a TCDA/DMPC/CHAPSO bicellar mixture showed many discoidal assemblies at x TCDA/DMPC = 0.5 of TCDA/DMPC = 5/5. Polymerization of the TCDA molecules in the bicellar mixture by UV light suggested an ordered arrangement of TCDA. Polymerization at x TCDA/DMPC = 0.70 and 0.50 correlated with improved packing density.

To fabricate fully printed carbon-based multiporous-layered-electrode perovskite solar cells (MPLE-PSCs), a polymer binder thickener had to be added to the carbon paste for the conductive carbon electrode. The polymer binder thickener is a key material to control the dispersion of carbon particles, viscosity for screen printing, and thickness and porosity of carbon electrodes. In this work, the role and effect of polymer binder thickeners for high-temperature carbon porous electrodes on MPLE-PSCs have been investigated in detail. Several carbon pastes with/without polymer binder thickeners (4 types of ethyl cellulose and 2 types of hydroxypropyl cellulose, which have different viscosities) were compared. What we understand in this paper are (1) Aggregation and dispersion of carbon particles are controlled by the polymer binder thickener (ethyl cellulose and/or hydroxypropyl cellulose); (2) For the porous carbon electrodes, the polymer binder thickeners are carbonized during the sintering procedure at 400 °C and can be kept on the surface of carbon particles as the additional carbon surface skin, which improves the conductivity; (3) The polymer binder thickeners can help the formation of a fine mesoporous structure in the annealed carbon electrodes. Combinations of results between viscosity, thermal, and specific surface area analyses revealed the close relationship between device performance and printability, dispersibility, and porosity brought by the polymer binder thickeners. As a result, the addition of a 20 wt % polymer binder thickener improved the average power conversion efficiency (PCE) from 9.52 ± 2.04 to 10.86 ± 0.85%, achieving a champion PCE of 12.06%.

In this study, a novel reversible control method of particle dispersion/flocculation for nonaqueous solvent was developed. Titanium oxide was used as sample powder. Cyclopentasiloxane was used as solvent and Polyoxyethylene polyalkylsiloxane was used as a dispersant. First, a well-dispersed slurry was prepared by adding dispersant. After preparation, alcoholic amphiphilic molecule was added to the well-dispersed slurry to convert it from liquid to a gel-like consistency, which was caused by the hydrogen bond of dispersant on the surface of the particles. The resultant gel could easily be changed to liquid state by shaking. In addition, the slurry reverted back to gel state after a certain period of time. It was found that the relative permittivity and the additive amount of amphiphilic molecule has an influence on the strength of the gel.

The effect of terephthalic acid particle properties on particle fracture phenomena was investigated in this study. Furthermore, to evaluate the fracture characteristics in real process, the effect of the particle impact angle on particle fracture phenomena was also investigated. The results of this study indicated that: (i) the crystallite size correlated with the fracture stress of the particle; (ii) the crystallite size also showed a correlation with the critical fracture velocity and the kinetic energy of the particle; and (iii) the particle fractured more easily at impact angles under 45°.

Evaluation of powder wettability is important to prepare well dispersed slurries. Therefore, in this study, a technique for evaluating powder wettability was developed to analyze the increase in the internal pressure of a closed powder bed due to capillary suction to determine the contact angle of the powder. The effect of the powder-bed-preparation method and powder surface area estimation method on the determined value of the contact angle was discussed. We demonstrated that the improved air permeation test proposed in this research can accurately determine the powder surface area, resulting in a faithful determination of the contact angle of the powder. It was also shown that compression under the shearing method could result in a denser and more homogeneous powder bed when compared to the conventional tapping method, indicating high reproducibility for estimating the contact angle.

Evaluation of powder wettability is important to prepare well dispersed slurries. Therefore, in this study, a technique for evaluating powder wettability was developed to analyze the increase in the internal pressure of a closed powder bed due to capillary suction to determine the contact angle of the powder. The effect of the powder-bed-preparation method and powder surface area estimation method on the determined value of the contact angle was discussed. We demonstrated that the improved air permeation test proposed in this research can accurately determine the powder surface area, resulting in a faithful determination of the contact angle of the powder. It was also shown that compression under the shearing method could result in a denser and more homogeneous powder bed when compared to the conventional tapping method, indicating high reproducibility for estimating the contact angle.

Previously, we have reported the successful preparation of a soft flocculated suspension. This is a suspension in which fine particles are well dispersed by using a polyelectrolyte dispersing agent, and then Mg²⁺ ions are added to crosslink between the dispersants adsorbed on the surfaces of the particles, so that the particles temporarily return to a liquid state with light shaking while behaving as gels at rest. In the present work we tried to apply this soft cohesive suspension as a low viscosity suspension of titanium dioxide having high versatility as a cosmetic powder. The use of globular titanium dioxide with a low yield value resulted in the successful development of a soft cohesive suspension with no precipitation or deposition of particles. In addition, when the application of this suspension in a white inkjet ink was examined, both the addition molding to a solid powder product using a piezo type cartridge and the printing experiment with a home printer using a thermal type cartridge showed the good results.

In this study, the fracture phenomenon of particle impacting with wall was directly observed using a high-speed camera. The results from the experiments indicate that the fracture behavior differs in the impact angle, and there are two types of fracture mode: one is with “Break” and the other with “Chip”. In case of low impact angle condition (less than 70°), there is only “Chip” mode. Furthermore, the effect of the particle impact angle on particle fracture phenomena was also investigated. The results of this study indicate that the particle fracture velocity almost is the same value at impact angles under 45° or higher.

Ion exchangeable inorganic fibers based on sodium silicate have been successfully developed. The fibers have the ion exchange capacity of 83.8 meq·100 g−1 which is comparable to that of ion-exchangeable resin. Absorbing glass mat (AGM) for separators in lead-acid batteries was also successfully prepared with ion-exchangeable sodium silicate fibers. It was clarified by charge/discharge cycle test and morphological observation with scanning electron microscopy that the ion exchangeable AGM can inhibit the precipitation of PbSO4 particles on the surface of electrodes and consequently reduces the deterioration in coulomb efficiency during repetitive cycles. Furthermore it was also clarified that ion-exchangeable AGM can inhibit the precipitation of PbSO4 in separator itself notably. This will allow the reduction of thickness of separator and downsizing of lead battery body.

Micellization of the Gemini surfactant sodium dilauramidoglutamide lysine (SDGL) in the presence of an antihistamine drug, diphenhydramine hydrochloride (DPC) was investigated. The anionic surfactant sodium dodecyl sulfate (SDS) was used for comparison. DPC significantly decreased the critical micelle concentration (cmc) of both SDGL and SDS in aqueous media and increasing the DPC concentration decreased the pyrene excimer/monomer polarity ratio in SDGL micelles but increased it in SDS micelles, suggesting that SDGL and SDS micelles have different shapes. The counterion binding and binding constant values reveal that SDGL micelles interact more strongly with DPC than SDS micelles. Thus, DPC, as an organic counterion, can enhance surfactant micellization. The evaluation of the solubility of a poorly water-soluble drug (clotrimazole) in SDGL and SDS micelles containing DPC revealed that the drug was more soluble in SDS micelles than SDGL micelles, indicating that the cmc and the shape and size of micelles are essential factors for controlling drug solubilization.

To minimize retention of nuclear fuel materials in glove box components and curtail the external exposure dose, plutonium and uranium mixed oxide powder adhesion prevention technology involving nanoparticle coating of the acrylic panels of the glove box is developed. The nanoparticle coating reduces the van der Waals force between alumina particles and the acrylic test piece surface because of formation of nano-sized rugged surfaces. The nanoparticle coating reduces the minimum adhesion force normalized by the particle diameter between the uranium dioxide particle and the acrylic test piece surface, for the smallest particle of about 5 µm associated with desorption, this minimum adhesion force reduced to about 5%. The nanoparticle coating also lowers the adhered plutonium and uranium mixed oxide powder amounts on the acrylic test piece to about 10%. This study reveals that applying the nanoparticle coating to the acrylic panels of the glove box prevents adhesion of nuclear fuel materials. This method effectively reduces the retention of nuclear fuel materials in the glove box, lowers the external exposure dose, and improves the visibility of the acrylic panels.

In this study, the effect of multivalent ions on ionic crosslinking of polyelectrolytes adsorbed on particle was investigated. Ammonium polycarboxylate, one of the typical polyelectrolytes, was used as a dispersant. Zinc oxide and titanium oxide was used as sample powder. A well-dispersed slurry was prepared by adding polyelectrolytes as the dispersant beforehand. Thereafter, multivalent cations were added to the slurry to convert it from liquid to a gel-like consistency, which was caused by the ionic crosslinking of polyelectrolytes adsorbing on the surface of the particles. It was found that the ionic radius of adding multivalent cation has an influence on the strength of the gel. It was also shown that this method was effective for prevention of density segregation during sedimentation.

The effect of terephthalic acid particle properties on particle fracture phenomena was investigated in this study. Furthermore, to evaluate the fracture characteristics in real process, the effect of the particle impact angle on particle fracture phenomena was also investigated. The results of this study indicated that: (i) the crystallite particle size correlated with the fracture stress of the particle; (ii) the crystallite particle size also showed a correlation with the critical fracture velocity and the kinetic energy of the particle; and (iii) the particle fractured more easily at impact angles under 45°.

We examined the effect of high pressure on the sol–gel phase transition of a resorcinol–formaldehyde (RF) aqueous solution to a RF hydrogel, which was hold under a certain pressure varied in the range from the ambient pressure to 400 MPa. By employing the dynamic light scattering method, we analyzed the scattered intensity of a He–Ne laser which was irradiated to the RF solution to determine the hydrodynamic diameter of the structure formed during the phase transition. Before the completion of the phase transition, we measured the transient change in the size of colloidal particles, i.e. the unit of the porous structure formed in the RF hydrogel. It was revealed that the size of the colloidal particles increased with the increase in the pressure added to the RF solution. After the completion of the phase transition, we prepared a RF cryogel by removing solvent from a RF hydrogel by freeze-drying. The specific surface area of the RF cryogel was found to decrease with the increase in the added pressure, as a result of the increase in the size of the unit of the porous structure.

In this study, a novel reversible control method for particle dispersion/flocculation was developed with the dual aim of preventing settling/sedimentation during storage and maintaining low viscosity in use. First, a well dispersed slurry was prepared by adding polyelectrolytes as dispersant. After preparation, multivalent cations were added to the slurry. By adding multivalent cations, the well dispersed slurry was changed to gel state because of the ionic crosslinking of polyelectrolytes adsorbing on the surface of the particles. The resultant gel was very soft and could easily be changed to liquid state by shaking. In addition, the slurry reverted back to gel state after a certain period of time. The softness of gel can be controlled by additive amount of multivalent cations. Thereby, a novel reversible control method for particle dispersion state was successfully developed.

We examined the degradation of aqueous phenol by ozonation in an aerated mixing vessel, which was combined with a fixed-bed reactor packed with high-silica zeolite (HSZ) pellets. Ozone-containing oxygen gas was introduced as fine bubbles through a sparger placed in the aerated mixing vessel, whereas the aqueous phenol solution was circulated between the vessel and the reactor. Measurements of transient changes in the concentration of both phenol and total organic carbon in the treated solution revealed that the degradation of phenol or total organic carbon by ozonation was enhanced by the presence of HSZ because both phenol and ozone could adsorb on the hydrophobic micropores. As a result of quantitative analysis of the treated solution, it was found that catechol, hydroquinone, humic acid, and maleic acid were the possible reaction intermediates during ozonation of aqueous phenol employing HSZ.

In this study, the mechanism of granule fracture under biaxial compression was investigated through both experimental and simulation methods. The results of the experiment indicate that the fracture behavior differs depending on the number of compressional axes. The fracture load under the biaxial condition is smaller than that under the uniaxial condition because in the latter, the compressed granule can be deformed planarly, whereas in the former, the compressed granule can be deformed into only one axial direction that is not compressed. To investigate this phenomenon in detail, finite-element method (FEM) analysis was used to analyze the tensile stress inside granules. The results of the FEM simulation indicate that the dominant factor in fracture phenomenon is tensile stress at the center of granules. From these results, it will be possible to theoretically predict, without any complicated experiments, the likelihood of fracture in granules.

In this study, a novel reversible control method for particle dispersion/flocculation was developed. We found that the conformation of a polymer with solubility pressure dependencies on the side chain changed from random coil to fibril-like with ambient pressure. On the contrary, as we reported in our previous paper, the dispersion state of slurry changes with changes in the conformation of adsorbed polymers. Based on these results, we hypothesized that the dispersion state of the slurry can be reversibly controlled by ambient pressure. The sample used was aqueous slurry of alumina with a sodium salt of sulfonic acid copolymer with a relative molecular mass of 10000. The results showed that the dispersion state of slurry at atmospheric pressure was flocculated with a specific additive amount of polymer. On the contrary, after pressurization, the dispersion state was changed into a well dispersion state. Therefore, it was confirmed that the slurry was responsible for the pressure thereby, a novel reversible control method for particle dispersion state was successfully developed.

SnO2 quantum dot was successfully synthesized at ambient temperature via ozone bubbling to suspension including Sn6O4(OH)4 under pH of 12. It was clarified that use of SnF2 as starting material enables to obtain clear and stable SnO2 quantum dot suspension. Possible formation mechanism of quantum dot was proposed and shift of fluorescence was predicted with use of varied basic solution for neutralization and pH adjustment based on the hypothesis that shift of fluorescence is attributed to change in size. And this prediction was confirmed by experiment. Finally addition of Zn as dopant gave improved luminescence intensity without shift of fluorescence. SnO2 quantum dot developed in this work does not include any cadmium, thus application as alternative to conventional CdSe and CdS is expected.

A new synthetic route to prepare yttrium barium copper oxide superconductive fibers using electrospinning in conjunction with the polymerizable complex method was developed. The as-spun fibers exhibited wool-like tactility and were 5-7 mu m thick. The fibers therefore exhibited sufficient flexibility to be fabricated into arbitrary shapes. Although the fibers shrunk and exhibited brittle tactility because of the decomposition of organic compounds during heat treatment, the fibers predominantly maintained their fibrous form. Scanning electron microscopy observations revealed the growth of metal oxide grains during sintering. Powder X-ray diffraction pattern of the annealed fibers showed good agreement with the pattern of YBa2Cu3O7-delta. Magnetic property measurements of a ground fiber sample using a superconducting quantum interference device revealed that the superconducting transition temperature of the sample was 91 K. (C) 2017 The Ceramic Society of Japan. All rights reserved.

The recent attention to energy-saving housing has increased demand for high-performance heat insulators. Among several heat insulators, inorganic fibrous heat-insulators have various merits, but production costs are still high. This work proposes a fabrication process of water glass fibers by centrifugal spinning using a concentrated aqueous solution of sodium silicate as spinning solution. It was found that fiber thickness and distribution are strongly affected by the process parameters, and that larger centrifugal gravity provides thinner and more uniform fibers. In contrast, the viscosity of spinning solution scarcely affected the thickness and uniformity of fibers, and a spinning solution with viscosity of more than 3 Pa.s and less than 150 Pa.s gave fibers stably. Humidity-resistant fibers were produced by carbon dioxide gas treatment at over 100 degrees C. Thermal conductivity measurement revealed that the optimal value was 0.027W/(m.K), which is comparable to that of air in the absence of convection. This value was similar to that of commercially available glass wool, but the mass of fiber required was about one-half, which would be effective for cost reduction.

Xerogels of large specific surface area have been successfully prepared by optimizing sol-gel process without any templates. It was found that the optimum solvent to obtain gels of large specific surface area is 1-propanol and the optimum molar ratio of solvent to alkoxide is 10. It was also clarified that the consecutive addition of water to reaction system by introducing humidified air is critical to specific surface area and that with humidified air the less initial content of water can provide gel of larger specific surface area. Consequently silica gel with specific surface area of 1869 m2/g could be obtained. Titania gel with specific surface area of 597 m2/g was successfully prepared by using ammonium acetate as catalyst together with above mentioned strategy. Obtained titania gel was used as support material of Ni nanoparticle and the catalytic activity was tested then compared with commercially available non-porous titania fine particle and commercially available silica gel. As a result, the significance of catalyst-support interaction and improvement of loading amount of catalyst nanoparticles attributed to porosity were confirmed.

To study solute distribution at the solid-liquid (S-L) interface during melt crystallization, we examined the applicability of the interfacial solute distribution factor proposed based on a kinetic model involving both mass and heat balances at the interface. The factor derived from the model was compared with the experimental results obtained by employing a binary melt with the different species and concentrations of fatty acids as biodiesel related mixtures. As a result, we were able to reveal the empirical relation between the purity of the crystal and the solidification conditions of the melt. Based on the model, we also numerically calculated the transient changes in the interfacial solute distribution factor as well as the temperature of the S-L interface in the solidification process of the melt. The minimization of the factor was confirmed when the melt was supercooled at the S-L interface after starting solidification. (C) 2015 Elsevier Ltd. All rights reserved.

Flame made gray titanium oxide particles which exhibit visible light absorption were successfully prepared via reduction atmospheric flame synthesis process. It was clarified that the particles have high specific surface area and are of nanometer size as a result of FE-SEM observation and specific surface area measurement. Particle properties could be varied by controlling equivalence ratio and introducing cooling gas, and the specific surface area increased as equivalence ratio increased. It was revealed that the particles are hollow for φ ＝ 1.54，1.68 and the constituent particles of shells are quite small in size. And the introducing of cooling gas affects the color of particles attributed to the oxidation degree and the specific surface increased as well. The result of XRD spectroscopy did not clearly show the generation of any magneli phases, however the peak intensity of anatase phase decreased which suggests the repression of oxidation. It was confirmed that carbon is rarely included in products and the change in color can be attributed not to carbon but to oxygen defect as a result of Raman spectrometry. Furthermore, the measurement of electric conductivity demonstrated the drastic improvement compared to stoichiometric titanium dioxide.

Centrifugal spinning of fibers with core-shell structure was tried by developing double tube nozzle spinneret. Obtained fibers were classified into three types according to fiber size. It seems plausible to infer that thin fibers are composed of only core material and thick ones are composed of only shell material. By contrast, it was clearly confirmed by observation with optical microscope that fibers have core-shell structure for medium size range around 10μm in diameter. In order to discuss the condition to obtain core-shell structured fiber, analysis based on the Hagen-Poiseuille equation focusing on the exit velocity at tip of spinneret has been conducted. As a result, relatively good agreement in exit velocity was found between core and shell materials.

When nano-sized tiny roughness is processed on a surface, the prevention of dust adhesion can be expressed by the decreasing of the van der Waals force between rugged surface and dust particle. Using nanoparticle coating on a textile, the tiny roughness can be created on a textile and the preventive effect of dust particle adhesion can be given to the cloth. This effect is applicable to working clothes etc. Generally, clothes are washed in order to remove the dirt on it, so the nanoparticle coating on a textile and the preventive effect of dust adhesion may be decreased by washing process. In order to add the functionality to the preventive effect of dust adhesion on the clothes in a practical uses, the improvement in the durability for washing is very important.<br>In this research, we confirm the preventive effect of dust adhesion and measured the effect of the number of washing on the preventive effect of dust adhesion on a textile. From our experimental results, the durability of the nanoparticle coating and the preventive effect of dust adhesion can be improved using acetalized polyvinyl alcohol treatment.

It is very important to control the particle dispersion state of slurries in order to fabricate better products in wet shaping processes. Therefore it is very important to evaluate slurry characteristics to predict the product characteristics. As a result, many studies have evaluated the slurry characteristics in various ways, such as measuring apparent viscosities, gravitational settling etc. However, it has been reported that these evaluation methods do not always have a good relationship with the quality of the final products. It is thought that one of the reasons for this is the fact that the method used was inappropriate for the actual situation. Several methods useful for the material fabrication process, such as measuring apparent viscosities and gravitational settling, are explained in this paper. Furthermore, an evaluation method proposed by our group to predict in a short time the packing characteristics of a slurry by measuring the hydrostatic pressure of the slurry at the base of a settling tube is also explained.

The preparation technique to obtain purely inorganic silica doped titania fibers using electrospinning together with sol-gel method was proposed. For the system without silicon doping, fibers were too brittle to form long fiber. And it was clarified that small amount of doped silicon could modify the flexibility of fibers drastically and long fibers with appropriate mechanical property could be obtained. After calcination at 500 degrees C for 2 h anatase phase was appeared and the specific surface area of fibers with composition of [Ti]/[Si] = 6 showed highest value 71.9m(2)/g among all the samples tested, which is even higher than typical fine particles. The result of decomposition experiment of Rhodamine B dye solution showed that the silica doped titania fiber has adequate photocatalytic activity to decompose organic matters. (C)2014 The Ceramic Society of Japan. All rights reserved.

In various industrial processes such as wet shape forming of ceramics, particles are usually applied in a slurry. In such processes, adding the appropriate amount of dispersant to the slurry is important for the production of better products. The adsorption of dispersant onto the particle surface is an important factor ; hence, many researchers have reported this phenomenon. However, few researchers have studied the effect of adsorption conformation of dispersant on dispersion stability. We investigated the effect of adsorption conformation of ammonium polycarboxylate, an adsorbed anionic polymeric dispersant with a molecular mass of 8000～10000, onto alumina. In this paper, several results of our recent research, such as the effects of additive amount of dispersant, dissolution of ion in the slurry, and effect of time at which dispersant conformation changes on dispersion stability of the slurry, are introduced.

© 2014 International Society for Industrial Process Tomography. The capping phenomenon means the powder adheres to the piston at the powder compression process and is one of the important causes of the powder molding trouble. The capping phenomena were difficult to discover in a compression molding process. The capping region can be detected from X-ray computed tomographic images and slipping angle of the capping area can be measured. From the experimental results, it’s clear that the capping phenomena easy to occur in the case of wider size distributed granules. So the capping phenomena can be prevented to use coarser mono-sized granules for compression molding.

In order to determine the preparation time for slurry in ceramic manufacturing processes, the effect of the conformation of ammonium polycarboxylate, an adsorbed anionic polymeric dispersant with a molecular weight of 8000～10000, on the dispersion stability of the slurry was investigated. The slurry preparation time was varied and the effect was investigated using and hydrostatic pressure measurement. The results of the investigation showed that the conformation of adsorbed polymers changed with time from random coil to fibril-like and that it took several days for the polymers to relax completely in the slurry. Furthermore, the dispersion state of the slurry changed with the relaxing of the conformation of adsorbed polymers. The results showed that the stretching of adsorbed polymers contributed significantly to the dispersion state of the slurry. The optimum conditions of polymers for the preparation of the slurry are also discussed.

The glass substrate is coated by the silica nanoparticle suspension using dipping or spin coat method and dried in an electric oven. The glass substrate surface is covered with nanoparticle thin layer and the transparent and tiny rugged surface can be produced on a substrate. It was experimentally confirmed to prevent dust adhesion by covering the surface of the glass substrate with nanoparticle. But the reason why the prevention of particle adhesion on nanoparticle coating substrate is not clear yet. Therefore the adhesion force between particle and substrate is measured by the centrifugal method and the relation between the adhesion force and the surface roughness is discussed from experimental and theoretical point of view. The measured and calculated results by Van der Waals force show that adhesion force decreased with the increment of the surface roughness. From the results, nanoparticle coating is very effective to prevent the dust adhesion on the substrate and the various application of nanoparticle coating can be expected.

We have developed a non-contact measuring method of mixing process in the mixer using a micro focus X-ray computer tomography. And its effectiveness was demonstrated from the experimental observation of mixing process of two kinds of particle with different X-ray transmission. The cross sectional image of particle packed bed in the cylindrical container rotation type mixer was obtained from the X-ray transmission images, and the image analysis of these cross sections was performed. From the brightness of each particle image, the particle materials can be detected and obtains the ratio of each particle on every section.<br>The degree of mixing was calculated from the measured distribution of each particle, and the effect of the separation plate in the mixer on the mixing performance of a cylindrical container rotation type mixer was studied. The actual mixing state in the mixer can be measured by non-contact, and the mixing degree in the mixing process from cross-sectional image analysis can estimate directly was shown.

For the purpose of this work, several types of waste coolants from fixed-abrasive wire sawing (FAS) were filtrated, and the characteristics of the coolants and the retrieved solid materials were investigated. The all coolants consisted of water and glycol series with the boiling temperature of around 200 degrees C. However, the viscosity of each coolant were different due to the difference in the ratio of coolant components. Experimental results of pressurized filtration can be explained by a rate equation which we proposed. The concentration of diamond in the retrieved solid materials was less than 0.2wt%. Metal contents in the retrieved Si were measured by an inductively coupled plasma mass spectrometry (ICP-MS). The result indicated that quality of the retrieved Si is sufficient for the use as feedstock. The shaped Si was easily melted in a resistance heating furnace. We concluded that the Si powders in waste coolants from F AS can be used as feedstock.

In wet shaping, the amount of dispersant added to the slurry is a crucial factor in producing high-quality ceramic products. Many researchers have investigated the amount of dispersant that adsorbs to slurry particles. However, few studies have examined how the solid concentration of slurry affects the amount of adsorbed dispersant. In our previous work, we measured the amount of adsorbed dispersant at various solid concentrations and addition amounts of dispersant. In the present work, alumina particles containing magnesium as a sintering aid were used. The conformation of polyelectrolyte dispersant was changed by magnesium ions, and the adsorption isotherm showed a local maximum. In the case of laurate, some molecules remained in solution and did not adsorb to particles because of its thermal motion and few adsorbing sites. Consequently, the amount of adsorbed dispersant was affected by the diffusion of magnesium from the particles, the molecular weight of the dispersant, and the solid concentration of the slurry.

A new filtration method that a slurry is prepared in a well-dispersed state and filtered by a ceramic tube with a spiral guide rod has been developed in our previous paper. In this study, we attempted to concentrate various hardly filterable materials by using this new system. The sample slurries used were sericite, iron oxide, algal suspension and activated sludge of the excrement of farm animals. Their respective concentrations were 57, 74, 1.1, and 7.55 mass%. The concentrated slurry of all samples exhibited good flowability. In addition, to apply this system to real industrial processes, we attempted to calculate the required number of ceramic filters from the relationship between the filtration flux and the slurry concentration. Thus, the size of this system is expected to be significantly compact. Furthermore, in this system, there is a case that the batch operation is more effective than the continuous operation. (C) 2011 Elsevier B.V. All rights reserved.

The hydrostatic pressure measurement method is one of the settling methods of a particle size distribution measurement. We measured the particle size distribution of the alumina slurries by this method and investigated the effects of the slurry concentration. However, the measured cumulative undersize is evaluated to be smaller than the true value at the high concentration because of the hindered settling. Therefore, in order to correct this phenomenon, we tried to use several equations of hindered settling suggested until now and the experimental equation. As a result, the particle size distribution of high concentration slurry can be measured without any dilution operations by using fitted experimental equation. Furthermore, the mean particle size measured by this method was closer to nominal value than the one measured by the laser diffraction method.

The effects of sintering aid adsorption on the dispersion properties of aluminum oxide slurries were investigated. We considered Al2O3 slurry without additives and Al2O3 slurry with a Mg additive with 0.1 mass% in oxide equivalent as a sintering aid. In this study, we evaluated the adsorption isotherm of polyacrylic acid (PAA) onto Al2O3 and the dispersion degree of Al2O3 slurries in sedimentation tests under gravity. The adsorption isotherm featured a characteristic adsorption isothermal line with a maximum value when Mg additive was present in Al2O3. In addition, the packing fractions did not correspond to the apparent viscosity. However, in slurry that was allowed to settle for several days, both of them agreed. Therefore, the disagreement between the packing fraction and the apparent viscosity immediately after preparation arose from changes of the dispersion state, such as the decrease of the distance between particles with time. (C) 2010 Elsevier Ltd. All rights reserved.

A new synthesis route to hydroxyapatite microsphere was proposed. Starting from the W/O emulsion system, micron-sized precursor particles were formed autonomously. It was clarified that pH of water during hydrothermal treatment can affect the morphology of resultant hydroxyapatite particles. Particles of irregular shape could be obtained via hydrothermal treatment under ambient pH, by contrast under high-pH conditions resultant particles retain the spherical morphology of precursor particles. It was also clarified that obtained hydroxyapatite particles have negatively charged surface, which is opposite to those by general synthesis method such as precipitation. Eventually it was confirmed that lysozym which is positively charged protein can be adsorbed on the obtained hydroxyapatite particle but albumin which is negatively charged can never be adsorbed.

A new filtration system with a spiral guide rod in a ceramic tube and slurry prepared in a well dispersed state has been developed. This paper discusses the optimization of operating conditions such as the effects of the spiral guide rod, the pitch of the spiral guide rod, the filtration pressure and the flow rate of circulation on the filtration flux. In addition, using a filter after filtrating dense slurry, ultrasonication test and repeated filtration tests in short and long intervals were carried out. In this system, it was shown that the filtration flux was dramatically improved compared to the conventional cross-flow filtration system. The filtration flux increased with the flow rate of circulation and did not depend on the filtration pressure. The achieved optimal value of the pitch produced the maximum filtration flux. It was also shown that fouled particles can be removed easily and the filtration flux can be recovered to the initial condition by ultrasonication. (C) 2010 Elsevier B.V. All rights reserved.

We prepared alumina slurries containing the same additive amount of dispersant in various solid concentrations, and observed gravitational settling behavior. Here, the additive amount is defined as the added dispersant mass per unit particle mass. Ammonium polycarboxylate was used as a dispersant. It was found that the settling behavior critically changes at a certain solid concentration and an additive amount of dispersant ; For the flocculated slurries, the settling behavior changed over 20 vol%, all particles in the slurry formed a network structure. The assembling state of particles in the slurry changed from strongly flocculated to well dispersed by small increase of additive amount of dispersant. It was also found that slurries, which have the same additive amount of dispersant, show the same settling behavior. From these results, it was shown that the settling behavior of particles can be dominated by not the dispersant concentration but the additive amount of dispersant.

A new cake-less continuous filtration system with a spiral guide rod inserted into a ceramic tube filter and slurry prepared in a well dispersion state has been developed We tried to filter some difficult to filter materials such as iron oxide and activated sludge Especially, the algal suspension and activated sludge was not able to be filtrated by a conventional filtration system like filter press Concentrated slurries of iron oxide and activated sludge were discharged at 35 vol% and 7 55 mass% respectively The concentrates of every sample retained flowability In addition, to apply this system to a real process, we tried to calculate the filter tube number from the relationship between the filtration flux and slurry concentration As a result, the size of this system can be expected to be very compact Also, in this system, the batch operation was more effective than continuous operation