Simulation of primary-slag melting behavior in the cohesive zone of a blast furnace, considering the effect of Al2O3, Fe t O, and basicity in the sinter ore

The alumina content in the iron ore imported to Japan is increasing year by year, and some problems in blast furnace operation, due to the use of the high-alumina-containing sinter, have already been reported. In order to clarify the mechanism of the harmful effect of alumina on the blast furnace operation, the behavior of the primary melt, which is formed in the sinter at the cohesive zone of the blast furnace, has been simulated by dripping slag through an iron or oxide funnel. The effects of basicity, Al₂O₃, and Fe _t O contents in the five slag systems on the dripping temperature and weight of slag remaining on the funnel have been discussed. It was found that the eutectic melt formed in the sinter would play an important role in the dripping behavior of the slag in the blast furnace through the fine poreosity of the reduced iron and ore particles. Al₂O₃ increased the weight of the slag remaining on the funnel, and its effect became very significant in the acidic and low-Fe _t O-containing slag. It was estimated that the increase of the weight of the slag remaining on the funnel by Al₂O₃ in the ore could result in a harmful effect on the permeability resistance and an indirect reduction rate of the sinter in the blast furnace.     

Why Some Bucky Tubes Would be Metallic?

As a reply to the title question, it has been elucidated that metallic bucky tubes are equivalent to those involving plural numbers of isolated polyacetylene (PA) skeletons (cis-type) arranged either in a helical or non-helical manner on the tube surface. Such helical PA skeletons guarantee the metallic conduction path to the electrons near the Fermi level (spiralons). Control of the flow of these spiralons may open up a stage for nano-technology of the electronic devices such as molecular solenoid applicable to molecular electromagnet, molecular electric generator and so on.     

A muprobe system with a compact electrostatic lens

A muprobe system has been constructed for a 4.75 MV Van de Graaff using a compact electrostatic quadrupole triplet lens. The beam-energy homogenizer is used to improve the beam transmission through slits. The beam intensity profile is measured by scanning the beam on a copper grid. The minimum beam-spot size obtained is (4.5 ± 1.6) μm × (12.2 ± 2.1) μm for 3 MeV protons with a beam current of 1.5 nA.     

Corona Current Control by Mesh Grid

Corona charging is widely used for charging dielectric surfaces. It is desirable to attain precise and uniform surface voltage in its application. A corona charging method using a mesh grid is described. It is found that the corona current control characteristics by mesh grid can be expressed by a nondimensional parameter?the corona current transmission rate. This parameter is obtained experimentally. The method of parameter application in dielectric surface charging is expressed by a differential equation. This technique is applied to charging amorphous selenium xerographic plates and to neutralizing the charges on a dielectric surface. It is found that the surface voltage obtained by charging with a mesh grid is far more uniform than that obtained by charging without a mesh grid.     

Theoretical Study on the Chemistry of Intergranular Glassy Film in Si3N4–SiO2 Ceramics

The intergranular glassy film (IGF) composed of silicon oxynitride in a Si₃N₄ ceramic material has been studied by molecular dynamics calculations. Structural analyses showed that the presence of an IGF having both nitrogen and oxygen reduces the number of dangling bonds at the junction between the IGF and adjacent Si₃N₄ grains, which reduces the interface energy at the grain boundary. More dangling bonds were generated at the junction when the N/(N + O) ratio of the IGF was decreased due to the larger chemical and structural mismatch between the IGF and the adjacent grain. On the other hand, the increase in the N/(N + O) ratio of the IGF caused a greater energy penalty in the IGF. The balance of these two contributions should determine the chemistry of the IGF.     

The pressure effect on the thermodynamic properties of polystyrene—trans-decalin solution

The viscosity of a solution of polystyrene in trans-decalin was measured over pressure and temperature ranges from atmospheric pressure to 400 kg/cm² and 20° to 40°C. The viscosity measurements at elevated pressure were made by the use of a rolling-ball type viscometer, and the validity of this method was confirmed by comparing with the calibrated Ubbelohde viscometer at atmospheric pressure. Values of the interaction parameter, χ, were obtained from the coil expansion coefficients on the assumption of the fifth-power rule of the Flory theory for the expansion of the polymer molecules in the solution. χ₁ increases with increasing pressure. The pressure coefficient of the theta-temperature calculated from the pressure and the temperature derivatives of χ₁ is in good agreement with the result of Schulz et al. The values of χ₁ were compared with those calculated from the new Flory theory and the Patterson theory for polymer solutions. At lower pressure these theories predict the behaviour of χ₁ well, but at higher pressure the prediction becomes inaccurate.     

The luminance resolution characteristics of multi‐primary‐color display

Abstract— In this paper, the resolution characteristics of multi‐primary‐color (MPC) display systems are analyzed. That four‐primary‐color (4PC) displays can increase the effective resolution for achromatic images in the luminance domain by a factor of two as compared to conventional RGB‐based displays with MPC‐specialized subpixel rendering, which is proposed in this paper, is demonstrated. Five‐ and six‐primary‐color (5PC and 6PC) display systems can reproduce denser luminance data than conventional RGB‐based display systems and solve a problem of MPC displays, viz. an increase of production costs and a decrease in the aperture ratio caused by increasing the number of subpixels in one pixel. This is an essential advantage of MPC display systems, which is related to the combination of the proposed color‐filter architecture and image processing. Thus, a completely new advantage of MPC display systems, in addition to their well‐known capabilities of color reproduction and power saving, is proposed.     

Synthesis of Hierarchically Porous Hydrogen Silsesquioxane Monoliths and Embedding of Metal Nanoparticles by On‐Site Reduction

A facile synthesis of a new class of reactive porous materials is reported: hierarchically porous hydrogen silsesquioxane (HSiO_1.5, HSQ) monoliths with well‐defined macropores and mesopores. The HSQ monoliths are prepared via sol‐gel accompanied by phase separation in a mild condition, and contain micrometer‐sized co‐continuous macropores and high specific surface area reaching up to 800 m² g^?1 because of the small mesopores. A total preservation of Si–H, which is always an issue of HSQ materials, is confirmed by ²⁹Si solid‐state NMR. The HSQ monolith has then been subjected to reduction of noble metal ions to their corresponding metal nanoparticles in simple aqueous solutions under an ambient condition. The nanoparticles produced in this manner are immobilized on the HSQ monolith and are characterized by X‐ray diffraction (XRD) and high angle annular dark‐field scanning transmission electron microscopy (HAADF‐STEM). Both the bare HSQ and nanoparticles‐embedded HSQ are promising as heterogeneous catalysts, exhibiting reusability and recyclability.     

Measurement of Particle Dynamics in Rapid Granular Shear Flows

Micromechanics of rapid granular flows is studied in a two-dimensional planar granular Couette flow apparatus. The device is capable of generating particulate flows at different shearing rates and solid fractions. Monosize plastic disks are sheared across an annular test section for several shear rates. The motion of particles is recorded through a high speed digital camera and analyzed by image processing techniques. The average and fluctuation velocity profiles are obtained and granular temperature relations with shear rate are investigated. Average streaming velocity across the shear cell decays slightly faster than exponential, and is rather Gaussian when not too close to the wall. Fluctuation velocities and granular temperature across the shear cell are related to effective shear rate. Interparticle collisions are estimated from the particle trajectories and probability distribution of collision angles obtained from particle collision data. In dense flows, three peaks of collision angles are observed, which signal the onset of triangular structure formulation and cause crystallization. It is found that the distribution of collision angles is anisotropic.     

Effect of Non-Newtonian Viscosity for Surfactant Solutions on Vortex Characteristics in a Swirling Pipe Flow

Effects of non-Newtonian viscosity for surfactant solution on the vortex characteristics and drag-reducing rate in a swirling pipe flow are investigated by pressure drop measurements, velocity profile measurements and viscosity measurements. Non-Newtonian viscosity is represented by power-law model (T = kD n). Surfactant solution used has shear-thinning viscosity with n < 1.0. The swirling flow in this study has decay of swirl and vortex-type change from Rankin's combined vortex to forced vortex. It is shown that the effect of shear-thinning viscosity on the decay of swirl intensity is different by vortex category and the critical swirl number with the vortex-type change depends on shear-thinning viscosity.