Cooking rate of spines of mackerels was experimentally examined at various temperatures in distilled water. Hardness (Fla) was determined by the m i m u m load applied in shearing the sample, F(N), divided by the maximum width of the sample, a(m). Sojiening rate could be described as a first-order reaction with reference to hardness with activation energy of 61 kJ/mol. Solubilization rate of organic matter and release rate of ash from fish bones were determined. Solubilization rate of organic matter was also described as a first-order rate process with activation energy of 73 W/mol. Ash was not released from fish bone during cooking.Hardness ajier cooking was proportional to the fourth power of degree of remaining of organic matter. It was suggested that hardness of cooked spine of mackerel was dependent on organic matter remaining in spine aJier cooking.Observations of surfaces of spine confirm that cooking caused change of mechanical structure in spine.

The rates of fish bone softening and solubilization of organic matter from it were determined in dilute acetic acid of concentration ranging from 0.0% to 3.0% at temperatures ranging from 80°C to 140°C. the first‐order constant of softening, kh(min−1), was described by the following experimental equation. where T is absolute temperature, °K, Ca is acetic acid concentration, %, and R is the gas constant, 8.314J K−1mol−1. the hardness of the bones was approximately proportional to the fourth power of the normalized weight of residual organic matter (the ratio of organic matter in the cooked bone to that in the raw bone). On the other hand, the dissolution of ash from the fish bone was hardly observed.

Quenching of a stainless-steel rod with a porous ceramic structure, i.e. honeycomb porous plate (HPP), attached to its lower surface was investigated in distilled water under saturated conditions at atmospheric pressure. The experiments were performed on bare surface (BS) and on a TiO2 nanoparticle-deposited surface (NPDS). When the HPP was attached, the quenching rate increased significantly on both tested surfaces. The quench time for the NPDS with the HPP it was 28-times shorter than that for the bare stainless-steel surface. The results suggested that the combination of the HPP ability to transport water to the heat-transfer surface by capillary action, and the increase of surface roughness, capillarity and wettability properties by the deposited nanoparticle layer were responsible for the enhancement obtained.

During a severe nuclear power plant accident, the integrity of the reactor pressure vessel must be assured. In response to a possible fuel meltdown, operators of the current generation of nuclear power plants are likely to inject water into the reactor pressure vessel to cool down the reactor vessel wall, preserving its integrity and avoiding leakage of radioactive material. This study considers the use of seawater to flood a reactor pressure vessel combined with the attachment of a honeycomb porous plate (HPP) on the vessel outer wall as a way to improve the safety margins for in-vessel retention of fuel. In long-duration experiments, saturated pool boiling of artificial seawater was performed with an upward-facing plain copper heated surface 30 mm in diameter. The resulting value for critical heat flux (CHF) was 1.6 MW/m 2 at atmospheric pressure, a value significantly higher than the CHF obtained when the working fluid was distilled water (1.0 MW/m 2). It was verified that sea-salt deposits could greatly improve surface wettability and capillarity, enhancing the CHF. The combination of artificial seawater and an HPP attached to the heated surface improved the boiling heat transfer coefficient and increased the CHF up to 110% (2.1 MW/m 2) as compared to distilled water on a bare surface. After the artificial seawater experiments, most of the wall micropores of the HPP were clogged because of sea-salt aggregation on the HPP top and bottom surfaces. Thus, the CHF enhancement observed in this case was attributed mainly to the separation of liquid and vapor phases provided by the HPP channel structure and improvement of surface wettability and capillarity by sea-salt deposition.

The enhancement of the critical heat flux (CHF) in saturated pool boiling of water-based nanofluid (containing TiO nanoparticles) by the attachment of a honeycomb porous plate (HPP) and a gridded metal structure (GMS) on a horizontal heated surface have been investigated experimentally. The honeycomb porous plate attached to the heated surface enhances the liquid supply due to capillary action to the heated surface and the release of vapor through the vapor escape channel. The deposition of nanoparticles on the heated surface during the boiling of the nanofluid enhances the spread of liquid along the heated surface due to the capillary action. The preceding papers