The effect of molybdate anion on the ion-selectivity of hydrous ferric oxide films in chloride solutions

The ion-selective property of hydrous ferric oxide precipitate films has been investigated by measuring membrane potentials which arise across precipitate membranes of hydrous ferric oxide with and without adsorbed MoO₄^2? ions and of ferric molybdate in solutions of NaCl, KCl, MgCl₂, CaCl₂, BaCl₂, AlCl₃, and FeCl₃. The hydrous ferric oxide membrane was only permeable to Cl^? ions in chloride solutions, whereas the membrane with adsorbed MoO₄^2? ions was permeable to cations in NaCl and KCl solutions, and to both Cl^? and cations in the presence of multivalent cations. The ferric molybdate membrane was permeable to Cl^? and cations in NaCl and KCl solutions, and only to Cl^? ions in the presence of multivalent cations. It is suggested that in chloride solutions, the corrosion of iron covered with a precipitate film of hydrous ferric oxide is accelerated by enrichment of Cl^? ions under the film, which may decrease the local pH and introduce a positive diffusion potential in the film. The adsorption of MoO₄^2? ions on the oxide changes the ion-selectivity of the precipitate film from the anion-selective to the cation-selective in solutions of NaCl and KCl. This cation-selectivity of the film may inhibit the corrosion of iron, because of H⁺ ions diffusing out of the film. The inhibitive effect of MoO₄^2? ions would be reduced in the presence of multivalent cations.     

Green's Function for Mixed Boundary Value Problem of Thin Plate

In this study, the Green's function of a point dislocation for the mixed boundary value problem of a thin plate is derived and then employed to analyze the interaction problem between a partially bonded rigid inclusion and a line crack in an infinite plate under uniform bending moments at infinity. A rational mapping technique and the complex stress function approach are used in the derivation. Based on the method of analytical continuation, the problem of obtaining the stress functions is reduced to a Riemann-Hilbert problem. Without loss of generality, the numerical results are demonstrated for a square rigid inclusion with a debonding. The stress intensity factors of crack tips and the stress intensities of debonding tips are shown for various parameters.     

Activated carbon nanofiber produced from electrospun polyacrylonitrile nanofiber as a highly efficient formaldehyde adsorbent

Electrospun polyacrylonitrile (PAN)-based nanofiber with a uniform diameter of ca. 800 nm was carbonized and steam-activated to produce activated carbon nanofiber with tailored microporosity and abundant nitrogen-containing functional groups as highly efficient adsorption sites. A remarkable amount of formaldehyde, a typical indoor pollutant, was adsorbed onto the pore surface of the PAN-based activated carbon nanofibers even at a low concentration (ca. 11 ppm), demonstrating more than twice as long as breakthrough time of formaldehyde adsorption as compared to conventional activated carbon fibers of larger fiber diameter. The tailored shallow microporosity was considered to afford the preferential adsorption of formaldehyde also in a humid environment.     

Batch foam separation of a soluble protein

Removal of protein dissolved in water by batch foam separation was conducted with using ovalbumin (OA) as a model protein in the light of wastewater treatment reducing organic loading. The removal efficiency had a maximum value near the i.e.p. of OA (pH 4.6); thus, most experiments were conducted at pH 4.6. Typical experimental conditions; superficial gas velocity, U(g): 1.97 x 10(-2)-5.37 x 10(-2)cm/s; initial bulk concentration of OA, C(i): ca. 0.05-0.25 g/L; liquid volume, V: 600 cm(3). A model estimating bulk concentration profile was proposed by taking into account a mass balance of the present system. The model predicted that OA could be removed perfectly, however, was not all removed experimentally. The residual OA concentration of the bulk liquid within the column reached plateau value, which correspond to ca. 18% of the initial OA concentration. The plateau value of the bulk concentration was attained for ca. 100-500 min with U(g)=1.97 x 10(-2)-5.37 x 10(-2)cm/s. Foaming ability test revealed that the foaming limit concentration of OA at pH 4.6 was 9.72 x 10(-3)g/L. These results suggested that OA molecules could be damaged by interaction of bubble surface in the dispersed phase, since there were the residual OA concentrations over the limit concentration. To take account of this phenomena and correct the model, average surface density, X(d), which should convert protein molecule into the denatured protein molecule, was introduced. The corrected model could explain well the time profile of OA bulk concentration.     

Case study of electrochemical metal removal from actual sediment, sludge, sewage and scallop organs and subsequent pH adjustment of sediment for agricultural use

In this paper we propose a method for chemical-free removal of metal from lake sediment, and its subsequent pH adjustment, based on electrochemical migration and precipitation. Such a method would enable the utilization of sediment as composting material. Sediment was placed in the anode side of a dual-bath electrochemical reactor separated by a thimble-shape cellulose filter from the cathode side, which was filled with pure water. When voltage was applied, contaminant metals in the sediment on the anode side migrated toward the cathode side, and precipitated due to the alkaline conditions caused by the cathodic reaction. After 10 days of electrolysis with 400 mA of constant current of 150 g wet lake sediment, the removal ratios of 13 kinds of elements after the electrochemical treatment were measured. Cd and Zn, the elements for which agricultural standards apply, showed 98% and 86% removal, respectively. The type of metal removed changed over time, and the order of removal was roughly from light metals to heavy metals. The acidified lake sediment after electrolysis could be neutralized without significant recontamination with Zn and Cd by using the alkaline cathode solution collected during electrolysis under a condition of tap water overflow at a rate of 1.5 L/h. The electrochemical metal removal method was effective not only for lake sediment, but also for municipal sludge cake, human sewage, and contaminated scallop organs. Cathode overflow during electrolysis tended to increase metal removal and decrease required voltage.     

Performance of a new low‐cost laser disdrometer with rainfall intensity correction in heavy rainfall

Recently, a new low‐cost disposable laser disdrometer with the capacity for hydrometeor imaging was proposed by the authors. The laser disdrometer has the drawback of detecting false raindrops, which are splashed droplets and pooled water drops on the housing. Actual raindrops can be sorted from false raindrops by their different fall speeds, but the large size and slow falling speed of false raindrops induce significant observational dead time, affecting the raindrop capture rate and the number density of the raindrops. The ratio between the actual number of raindrops and the total number of drops including the false raindrops provides a reasonable rain intensity correction. This report describes the performance of a laser disdrometer with rain intensity correction in heavy rainfall. © 2014 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Purification and some properties of cholesterol oxidase stable in detergents from gamma-proteobacterium Y-134

Cholesterol oxidase (CHO) with high stability in detergents was found from an isolated strain, Y-134, belonging to the gamma-subclass of Proteobacteria. CHO production reached its maximum by incubation at 30 degrees C for 12 d. It was purified from cell-free extract prepared by mixing the cells with 0.4% Triton X-100. The absorption spectrum of the purified enzyme exhibited maxima at 274 and 410 nm, and a shoulder at 330 nm. The molecular mass was 115 kDa with two identical subunits of 58 kDa. The enzyme oxidized cholest-5-en-3beta-ol (cholesterol) and 5alpha-cholestan-3beta-ol (dihydrocholesterol) at a high reaction rate, and the K(m) value for cholesterol was 65 microM. The stability of the enzyme was higher than other CHOs in nonionic detergents with high values of hydrophilelipophile balance (HLB) such as Triton X-450 and sodium cholate. NH2-terminal sequence analysis showed a high similarity to CHO from Burkholderia cepacia, but not to CHOs from Streptomyces or Brevibacterium.     

Thermal deformation measurement of the solder joints in electronic packages using electron moiré method

In this paper, electron moiré method is used to measure the thermal deformation of electronic packages. In order to observe the electron moiré fringe, a holographic grid was replicated on the cross section of the BGA type package at 150°C. This grid was fabricated on a glass plate using a moving point holographic system, and was replicated to measured area at high temperature. Under SEM, the holographic grid(specimen grid) and a programmed electron beam scan(master grid) interfere and form electron moiré patterns. The shear strain measurement technique using electron moiré method is described. Using the electron moiré method, the shear strains in the different solder joints were measured and analysed. Some useful results were obtained.     

Heat Source in Infinite Plane with Elliptic Rigid Inclusion and Hole

The plane thermoelastic problems of a stationary heat source in an infinite plane with an elliptic rigid inclusion and an elliptic hole are analyzed under thermally adiabatic and isothermal boundary conditions. The problems of an elliptic rigid inclusion are derived for the following cases: (1) the case that there are rigid-body displacement and rotation; and (2) the case that there is no rigid-body displacement or rotation. To analyze these problems, the following three fundamental solutions are derived: Problem A, in which a point heat source exists within an infinite domain; Problem B, in which the inclusion has a small amount of rotation; and Problem C, in which the inclusion is subjected to concentrated loads. Two cases can be obtained by superimposing these fundamental solutions. For the hole problem, the fundamental solution (Green's function) is also derived. In analysis, the complex stress functions, the mapping function, and the thermal dislocation method are used. The complex stress functions are obtained as a closed form. For analytic examples, the stress distributions are shown under thermally adiabatic and isothermal boundary conditions. For the crack problem, the stress intensity factors are shown for the location of the heat source.