Features of Rotating Stall Cell in a Diagonal Flow Fan（in Case of Mid-loading Rotor）

The structure and behavior of rotating stall cell were experimentally clarified in a diagonal flow fan. The specific-speed of the fan was 1140 (r/min, m3/min, m), and the total pressure-rise coefficient at design flow-rate was 0.345. The static pressure on outer casing wall and the total pressure at rotor inlet and outlet were measured using a high response pressure transducer. The measured data were processed by the use of DPLA technique, and the structure and behavior of rotating stall cell were obtained. As a result, the stall cell extent for circumferential and spanwise direction and the pressure distributions inside stall cell were clarified. The details of stall cell propagation were also shown.     

Crystalline properties of multiple BP-Si layers grown on silicon substrate

In BP (100) epitaxially grown on Si (100), a high density of defects existed in the early growth layer of the BP less than 100 nm from the Si interface. The BP layer then had a uniform distribution of defects over the high density defect layer. The Si (100) grown on the BP (100) had a uniform distribution of defects. As multiple BP-Si layers were grown, the crystalline quality gradually degraded. The crystalline quality of the underlying BP layer strongly influenced the Si epitaxial layer.     

Studies on synthetic-polymer plates with high surface energy. II. Diethylene glycol bis(allyl carbonate)–unsaturated carboxylic acid system

Polymer plates with high surface energy were prepared by the procedure described in the previous paper, using diethylene glycol bis(allyl carbonate) as a substrate polymer and acrylic acid or methacrylic acid as a hydrophilic monomer. By the alkali treatment (immersing in an aqueous 0.1N NaOH solution for 2 h), the resulting polymer plates had good water wettability (contact angle for water = 10°) and sufficient mar resistance (the scratching hardness = 45–50 g) in a dry state, and their clarities were higher than those for DAP systems previously reported. The surface densities of carboxyl groups on the polymer plate estimated by use of the McBain's equation were 0.18–0.46 molecule/Ų.     

The spatial distribution of Zn during galvanic corrosion of a Zn/steel couple

The spatial distribution of Zn²⁺ during galvanic corrosion of a model Zn/steel couple in 0.01 M NaCl was investigated using a scanning zinc disk electrode. The couple had a coplanar arrangement of a steel substrate with an electroplated zinc layer at the center. During galvanic corrosion, the marked changes in the Zn²⁺ concentration were confined to a thin solution layer ca. 1.0 mm thick above the couple surface. In this thin solution layer above the zinc layer, a higher concentration region of Zn²⁺ in the range of 5-18 mM extended around the zinc layer in the solution during galvanic corrosion. Conversely, above the steel surface distant from the zinc layer, the surface concentration of Zn²⁺ was almost zero during galvanic corrosion. On this surface, the precipitation of zinc corrosion products due to the hydrolysis reaction of Zn²⁺ was observed. The distribution of the Zn²⁺ concentration supported that Zn²⁺ acted as a buffer that suppressed the increased pH due to the cathodic reaction on the steel surface near the zinc layer and almost no corrosion products formed there. The spatial distribution of Zn²⁺ is discussed in relation to the distributions of potential and pH and the surface morphology of the galvanic couple.     

Classification of the Degradation of Soft Sensor Models and Discussion on Adaptive Models

Soft sensors are used widely to estimate a process variable which is difficult to measure online. One of the crucial difficulties of soft sensors is that predictive accuracy drops due to changes of state of chemical plants. It is called as the degradation of soft sensor models. In this study, we attempted to classify this degradation of models in terms of changes in an explanatory variable and an objective variable, and the rapidity of the changes. Moreover, we discussed characteristics of adaptive soft sensor models, based on the classification results. By analyzing simulated data sets and a real industrial data set, we could obtain knowledge and information on appropriate adaptive models for each type of the degradation. © 2013 American Institute of Chemical Engineers AIChE J, 59: 2339–2347, 2013     

Synthesis of rodlike polysiloxane containing polyol moieties derived from glucose with regularly controlled higher-ordered structure

A rodlike polysiloxane (3) containing polyol moieties derived from the sugar has been synthesized by reaction of an amine-functionalized rodlike polysiloxane (1) with gluconolactone (2) in the presence of triethylamine in DMF. Formation of 3 was estimated by the IR and ¹H NMR measurements. The functionality of 2 to the amino groups in 1 was ca. 75%, based on the ¹H NMR spectrum of the product. The XRD profile of 3 showed three peaks for a typical hexagonal phase, and the d-value of (100) peak of 3 was larger than that of 1, indicating the regularly controlled higher-ordered structure of 3.     

Radiation detector made of a high-quality polycrystalline diamond

Radiation detector was made of a high-quality CVD polycrystalline diamond composed of frost column like structure diamond grains, and induced charge distribution spectra and drift velocities were measured by using alpha particles. As a result, the CVD polycrystalline achieved maximum induced charge of 83% of HP/HT type IIa diamond. Moreover, the CVD crystal had lower charge loss on electrons compared with the HP/HT type IIa diamond. Drift velocities of electrons and holes were v_e = 7.7 × 10⁴ and v_h = 7.3 × 10⁴cm/s at an electric field of 20 kV/cm, respectively. In addition, response function measurement for 14 MeV neutrons was carried out.     

Radiation tolerance of type IIa synthetic diamond detector for 14 MeV neutrons

Radiation tolerance of a type IIa synthetic diamond detector was examined from irradiation of mono-energetic 14 MeV neutrons. Measurements of I–V (current–voltage) characteristics and energy spectrum for 5.486 MeV alpha particles were performed after neutron irradiation. In the I–V characteristics measurement, enhancement of rectification was observed after neutron irradiation of up to 2.0 × 10¹² n/cm². Concurrently with the enhancement of rectification, significant decrease in signal amplitude was observed in energy spectrum measurement for alpha particles. It is considered that these changes were due to increase in the concentration of defects acting as shallow energy levels in the forbidden band. For neutron irradiation of higher than 1.6 × 10¹³ n/cm², weakening of the rectification characteristics and recovery of the signal amplitude were observed. These changes imply that deep energy levels, which were also considered to be introduced by defects, were dominant and weakened the effects of the shallow energy levels. Increase in the concentration of the deep trapping levels resulted in gradual decrease of the signal amplitude and degradation in the energy resolution. The peak for the alpha particles was obtained up to 5.5 × 10¹³ n/cm².     

Voltammetric study of electrocatalysis for dioxygen reduction by trinuclear rutheniumammine complex confined in a polymer membrane

Electrocatalytic O₂ reduction was studied using a modified electrode coated with a Nafion membrane (Nf) dispersing a trinuclear ruthenium ammine complex ([(NH₃)₅Ru^IIIORu^IV(NH₃)₄ORu^III(NH₃)₅]Cl₆, Ru-red). When measuring cyclic voltammogram under O₂ atmosphere (at 0.5 mV s⁻¹), catalytic currents due to O₂ reduction were found to develop below −0.2 V (vs. Ag/AgCl). Since Ru-red undergoes irreversible decomposition into the mononuclear complexes via the reduced state (Ru^III-Ru^III-Ru^III) (∼−0.1 V), it is suggested that the electrocatalysis originates from the decomposed species (initial active species: Ru^II(NH₃)₅(OH₂) and Ru^II(NH₃)₄(OH₂)₂) rather than from the Ru-red. Although the present electrocatalyst was also applied to H₂O₂ reduction system, the catalytic activity was found to be poor from the voltammetric behavior. It appeared that the kinetics of the electrocatalysis is much faster in the O₂ reduction than in the H₂O₂ one. A selective and direct catalysis for O₂ reduction into H₂O was suggested from a ring-disk voltammogram to take place by an aggregate of the mononuclear ruthenium complexes in the polymer matrix. In addition, it was found that electrocatalytic O₂ reduction involves a slow kinetic process, so that factors affecting the overall kinetics were discussed in terms of the catalysis mechanism.