Critical heat fluxes of subcooled water flow boiling in a short vertical tube at high liquid Reynolds number

The steady state critical heat fluxes (CHFs) and the heat transfer of the subcooled water flow boiling for the flow velocities (u = 17.2-42.4 m/s), the inlet subcoolings (ΔT_sub,in = 80.9-147.6 K), the inlet pressures (P_in = 812.1-1181.5 kPa) and the exponentially increasing heat input (Q₀ exp(t/τ), τ = 8.5 s) are systematically measured by the experimental water loop comprised of a new multi-stage canned-type circulation pump with high pump head. The SUS304 test tube of inner diameter (d = 6 mm), heated length (L = 59.5 mm), L/d = 9.92 and wall thickness (δ = 0.5 mm) with surface roughness (Ra = 3.18 μm) is used in this work. The steady state CHFs of the subcooled water flow boiling for the flow velocities ranging from 17.2 to 42.4 m/s are clarified. The steady state CHFs are compared with the values calculated by our transient CHF correlations against outlet and inlet subcoolings based on the experimental data for the flow velocities ranging from 4.0 to 13.3 m/s. The influence of flow velocity at high liquid Reynolds number on the subcooled flow boiling CHF is investigated in detail and the widely and precisely predictable correlations of the transient CHF correlations against outlet and inlet subcoolings in a short vertical tube are derived based on the experimental data at high liquid Reynolds number. The transient CHF correlations can describe the subcooled flow boiling CHFs for the wide range of flow velocities at high liquid Reynolds number obtained in this work within ±15% difference.     

Approximate evaluation of cell resistance with resistive electrodes

The resistance of a cell composed of a resistive anode and a conductive cathode has been theoretically calculated by solving the two-dimensional Laplace equation for the solution phase where the anode has an overpotential of a linear type. Conditions were evaluated under which the cell resistance could be obtained on the assumption that the direction of the current flowing in solution was perpendicular to the electrode. These were not strongly dependent on the ratio of the interelectrode distance to the height of the electrodes. The main parameters which determine the conditions were the Wagner number and the ratio of the electrode resistance to the solution resistance.     

EXPERIMENTAL STUDIES OF DIFFUSION FLUXES F TERNARY DISTILLATION OF THE ACETONE-METHANOL-ETHANOL YSTEMS BY A WETTED-WALL OLUMN

Measurements of mass and diffusion fluxes for ternary distillation of the acetone-methanol-ethanol systems were made by a wetted-wall column under total reflux conditions for wide ranges of the liquid concentrations. Intermediate component methanol showed peculiar behavior of a finite mass flux near the zero-driving force region. This was explained as being due to the effect of the interfacial velocity caused by mass fluxes of the other components. The diffusion fluxes were shown to be proportional to concentration driving forces, whereas the mass fluxes were not. Discussions on the use of the number of transfer units for correlation of mass transfer data in ternary distillation were also made.     

Development of a complex mixed production system for plain paper copier machines

Manufacturers now face the challenges of increased product variety, the need for small-to-medium-quantity production, shortened product life cycles, and reduced costs due to changes in customer demand. Total factory automation, including the automation of assembly as well as indirect (overhead) functions, must be realized for these challenges to be met.

Ricoh's factory for the production of the Plain Paper Copier (PPC) has developed a new production system employing hardware, software and “humanware”. This system has an automated production support system (RINKS), assembly system, and physical distribution system. It is network composed of computer and terminals. This article discusses the development and implementation of Ricoh's system.     

On-line GPC/NMR experiments using the isotactic poly(methyl methacrylate) with well-defined chemical structure

Summary Gel permeation chromatography of. isotactic PMMA has been performed on a Chromatograph linked to a 500 MHz ¹H NMR spectrometer. ¹H NMR spectra of good resolution and high S/N ratio were collected over the entire Chromatographic peak. The Mn of the polymer sample can be directly determined by intensity measurements of the proton signals due to the endgroup and monomeric units, since the polymers used were prepared by the living polymerization initiated by t-C₄H₉MgBr. A good linear relation was obtained between the log(Mn) and elution time.     

Electron traps in n-InP grown by the synthesis solute-diffusion method

Deep electron trap levels in n-InP single crystals grown by the synthesis solute-diffusion (s.s.d.) method have been studied by d.l.t.s. and admittance-spectroscopy techniques. Three deep trap levels were found and the dominant trap level was shown to have a depth of 0.26 eV and capture cross-section of 0.9 ? 1.2 × 10?12cm2.