Wilson parameters were estimated from solubility parameters and molar volumes. Namely, the interaction parameters due to attractive forces were evaluated from the solubility parameters and molar volumes predicted by the group contribution method of Fedors. The vapor-liquid equilibria (VLE) of typical polar mixtures such as ethanol + hydrocarbon systems were correlated by use of these Wilson parameters, in which the interaction parameters between unlike pairs were adopted. The interaction parameters were determined by using VLE data and were correlated with the difference in cohesive energy densities of the two pure components.
Fluid mixing is normally deemed to be complete when the different fluid matters are uniformly distributed through the whole system. In a mixing system where a spontaneous and periodic reaction such as the Belousov-Zhabotinskii reaction (BZ reaction) takes place, however, all small fluid elements in the system can possess not only material characteristics such as the amount of reactants, but also information characterizing the dynamical mode, such as the period and the phase in the periodic concentration change. Moreover, this information can propagate to surroundings through short-range interactions without any fluid motion. In the fluid mixing operations accompanied by the BZ reaction, therefore, we can observe a different space-temporal concentration distribution from that in the usual fluid mixing system. In this study, by comparing the differences in the space-temporal concentration pattern change among a decolorizing reaction, a reversible color reaction, and a BZ periodic reaction, we consider the necessity of reconsidering the normal concept of fluid mixing.
The relative mixing performance of five versatile impellers (six-flat blade FBDT turbine type (FBDT), six-blade turbine type (FBT), six-45° pitched blade turbine type for up flow (PBT(Up)), six-45° pitched blade turbine type for down flow (PBT(Down)) and three-blade marine propeller type (Marine)) was investigated from the viewpoint of practical operation based on experimental data of whole mixing capacity (MW), which is defined by introducing the information entropy. When the average whole mixing capacity, the impeller revolution speed (Nmax) at the maximum MW (=MWmax), the response sensitivity of MW to the change in impeller revolution speed, the response sensitivity of the standardized MW based on MWmax (=MW/MWmax) to the change in impeller revolution speed, the MWmax for the unit mixing power consumption, the product of MW/MWmax and the spare mixing power consumption are chosen as parameters for relative mixing performance, the order of the mixing performance of the above five versatile impellers was as follows: FBT > FBDT > PBT(Up) > Marine > PBT(Down). It was clearly shown that FBT and FBDT in particular show excellent mixing performance compared to that of PBT(Up) or Marine or PBT(Down) from the viewpoint of practical operation.
Power consumption for an anchor impeller was measured over a wide range of Reynolds number from laminar to turbulent flow regions. In the laminar region, the power number of the anchor was reproduced by the correlations of Nagata and Kamei et al. by considering the anchor as a wide paddle impeller. In the turbulent region, it was reproduced by the correlation of Kamei et al. without correcting the parameters. If a large vortex was generated in a turbulent mixing vessel, the experimental values of power number were larger than correlation ones.
The effect of particle diameter of coconut shell-based granular activated carbons on the adsorption and desorption of organic compounds from solutions was studied. The adsorption of phenol and benzothiophene was examined for different particle sizes (0.053–0.588 mm) at 298 K in aqueous and hexane solution, respectively. The adsorption isotherm of phenol was well represented by the Langmuir equation and the amount of maximum adsorption was not influenced by the particle size. For both phenol and benzothiophene, the adsorption kinetics became faster with decreasing particle size. The desorption of phenol began before the adsorption equilibrium was reached, showing that adsorbate was rapidly desorbed from outer surface and subsequently re-adsorbed into the inner surface of the activated carbon. Analysis of the kinetics data revealed that the adsorption was represented by a pseudo-first-order equation during the first stage of the experiment, while a pseudo-second-order equation was given a better fit as time advanced. The adsorption model suggested in this work is discussed in terms of the mechanisms of phenol and benzothiophene adsorption onto activated carbon.
Infrared thermography is a convenient procedure by which to visualize and estimate various temperature fields of objective surfaces nondestructively by sensing energy emitted from them as electromagnetic waves. This technique allows a two-dimensional temperature field to be evaluated quantitatively, nondestructively and simultaneously at every picture element even though the object has a complicated shape. This increasingly recognized applicability has led to development of remote-sensing diagnoses for various engineering applications. However, the emitted energy transferred to an infrared sensor, which is usually used as a signal for determining temperature, will always include energy reflected from the surroundings as noise. In particular, it is difficult to apply infrared thermography directly to quantitative temperature measurement of glossy metal surfaces under near-ambient conditions, where the influence of the reflected energy becomes marked, and the measurement error is large. Distinguishing the signal for determining temperature from a signal detected with the infrared sensor is difficult in any case. For this reason, despite some creative research on infrared thermography, the present accuracy of measurement is still not satisfactory. The infrared sensing techniques proposed previously by the authors, two-colored and three-colored techniques, are further discussed for developing a more general nondestructive method of quantitative temperature measurement under near-ambient conditions. The three-colored technique for quantitative temperature measurement is modified by applying three kinds of newly-developed infrared filters simultaneously in the present study. A new hypothesis is also introduced. Each filter has a selective wavelength band of several μm in width in the range of 7–14 μm. The applicability was confirmed by empirical investigation allowing a parametric study of how the result varies for various surface conditions. We investigated the measurement error experimentally, and the effect of surround disturbance and directivity on the present technique. The modified method allows quantitative temperature measurement for target surfaces at each picture element without presuming any emissivity, reflectivity and ambient conditions, so that it may be useful across various medical, chemical, physical and engineering disciplines.
Huge, single-crystal nonlinear optic materials have been utilized for shortening the wavelength of high-power coherent light. If fine nonlinear optic powders can shorten wavelength of low-power incoherent visible light, they could be used in combination with fine visible-light phosphor powders to establish a dispersed ultraviolet-light source, which is considered effective for photocatalytic reactions. This proposition was indirectly verified by the enhanced decomposition rate of Orange II in water by a photocatalytic powder of TiO2 combined with nonlinear optic powder of reagent-grade LiNbO3. With the dispersed ultraviolet-light source generated from powders of visible-light phosphor and LiNbO3 from a single-crystal, the photocatalytic water decontamination rate of water was enhanced approximately 5-fold compared to the case of photocatalytic powder of TiO2 alone.
A dispersed ultraviolet light source that can excite a photocatalyst has experimentally applied for water decontamination by photocatalytic powder. As a potential source of dispersed ultraviolet light, the present study focuses on electroluminescence (EL), by which cold light is emitted in response to a changing electric field. CaWO4 powders with substituents of Mo or Cr, which are electroluminescent in the ultraviolet region, were prepared by a simple solid-phase thermal decomposition method. A higher decomposition rate of orange II in water could be obtained in a system of combined EL and photocatalytic powders, compared with the electrical discharge system. Moreover, doping of CaWO4 : Mo (3 wt%) powder with several metals on photocatalytic water decontaminating rate was found to be effective, and CaWO4 : Mo (3 wt%) : Ce (2 wt%) and CaWO4 : Mo (3 wt%) : Dy (1 wt%) were confirmed as the best EL materials for this process. Taking into consideration the materials, energy and time required for preparing these metal-doped EL powders, it was concluded that CaWO4 : Mo (3 wt%) is the optimum EL powder for practical utilization.
The relationships between the hierarchical classification based on the subjective assessment value and that based on the objective assessment value and between the safety factor based on the subjective ratio and that based on the objective ratio were investigated from the viewpoint of information entropy. In the case of the hierarchical classification, it was found that even if the subjective assessment value is divided into classes of equal width, the classes in the middle range have larger widths in the objective assessment value. This fact should be taken into account when the hierarchical classification result is discussed objectively. In the case of the safety factor, in order to set the safety factor with greater confidence, it is necessary to estimate the safety factor based not only on the old subjective ratio but also on the objective ratio converted from the subjective ratio.
Heme iron preparation (HIP) made from digested hemoglobin is known to be more readily absorbed by the human body than iron salts. In the present study, HIP was prepared from blood of cultured yellowtail, by denaturation of proteins, hydrolysis of hemoglobin using protease, and recovery of HIP by ultrafiltration. The dry mass, iron distribution, and molecular weight distribution of peptides in the permeate and the retentate after ultrafiltration were analyzed. Hydrolysis of hemoglobin using protease and quantitative recovery of HIP by ultrafiltration were confirmed. The molecular weight distribution of the resulting material as HIP was from 2,400 to 7,300. Efficiency of HIP recovery by ultrafiltration was compared using different ultrafiltration membranes. More than 95% of HIP was recovered by ultrafiltration using a membrane having a molecular weight cut-off of 20,000.
During cold startup of polymer electrolyte fuel cells (PEFCs), water freezing in the porous cathode is a critical barrier to achieving high power density. In this study, the freezing of water inside the cathode of a PEFC during low temperature operation was directly visualized using an optical diagnostic, and the correlation between the ice formation and the cell voltage characteristic was investigated. The effects of the structure of the gas diffusion layer (GDL) and operating conditions on the water freezing and cell performance were also discussed. It was found that the water generated in the cathode does not freeze immediately after starting the operation at −10°C. When the liquid water within the cathode freezes during the cold startup, the cell voltage drops due to the limitation of oxygen diffusion. Furthermore, the operation time below the freezing point is largely affected by the material properties of GDL, current density and cathode gas composition.
Incineration is the most common method of treating municipal waste. By this method, harmful organics are converted to harmless gases. However, the elution of harmful trace elements from the incineration ash is a cause for environmental concern. The present study examined the elution and leaching characteristics of fly ash packed in a column on elution with nitric acidic solution. At a certain stage in some experimental runs, the pH of the acid leachate decreased sharply, the flow rate of the leaching solution increased, and the concentrations of the main or major inorganic elements Al, Zn and Fe increased sharply. These phenomena were explained as follows. At the first stage of experimental runs, the major element Ca was dissolved, and the pH of the eluate increased with pH gradient in the column. The main or minor elements Al, Zn and Fe dissolved in the upper part of the column were precipitated at bottom of the column, leading to reduction of the flow rate of the leaching solution. With the complete dissolution of Ca, the eluate pH decreased, these deposits were dissolved and the flow rate increased. It was found that the leaching experiments depended strongly on packing conditions such as initial wetting of fly ash, the presence of cracks, packing density and packing height. The present study on leaching characteristics of fly ash suggested that a drastic increase in harmful trace elements might occur even after the pseudostable dissolution from a land-fill site.
In order to obtain fundamental data for developing an efficient recovery process of rare earth elements from Nd–Fe–B magnets, the release behavior of Nd, Pr and elements was investigated under the conditions of heating rate of 30°C/min and terminal temperatures from 100 to 1000°C in a Cl2 gas stream. Fe and B volatilizedin the low temperature region,while Nd and Pr were concentratedin the solid phase by the chlorination. Nd–Fe–B samples werepre-oxidized by heating at 500°C in air to prevent spontaneous combustion of the fine magnet powder. While Fe and Co in the oxidized magnet were volatilized during the chlorination, the rare earth elements and B mostly remained in the solid phase as water-insoluble forms. When carbon and SiC powders were added to the oxidized sample, Fe, Co and B were completely volatilized at 1000°C by carbochlorination. Nd and Pr were concentrated in the residue of the oxidized magnet sample. It was also found that Nd and Pr could be selectively recovered by leaching with water from the residue, because these elements formed chlorides by the carbochlorination.