A Pumice in Hokuriku District

Several kinds of pumice have been used as aggregate for concrete. In Hokuriku District，however，no pumice product has been reported before it was found near Kanazawa recently. The author carried out an experimental inves. tigation on this pumice in order to find the possible use for concrete. The expriment consisted of two series. The first was the tests of pumice itself. The results were obtained on sieve analysis， soundness by use of sodium sulfate， specific gravity and absorption， unit weight， fineness modulus. absorption rate，inorganic material and compressive strength. The second was the experimerits of pumice mortar. Compressive strength， tensile strength and Young's modulus of pumice mortar were about a half of those of sand mortar. The weight of the pumice mortar was 70 % of sand mortar. The water absorption of pumice mortar was twice as much as that of sand mortar

Investigation of old BuiIding Concrete (5)

An Investigation was carried out on the 40 years old concrete of Fukui Municipal Office bui1ding. The main results obtained are as follows; 1) The depth of alkali-lost in concrete was found to be 4.7～6.6cm in inside columns with plaster cover. These values are much greater than those estimated from the ever presented formula. In the foundations and outside walls with granite plate，however，the alkali-lost depth stayed within 2mm. 2) The mean value of compressive strength of concrete core was 148 kg/cm2， much lower than the value estimated from Schmidt Hammer's rebound number. Young's modulus was calculated as 1.60～2.06 (105kg/cm2)from the stress-strain rela tions. 3) The mixing proportion of cement，f ine and coarse aggregate was evaluated as 1:2.5～3.2:5.1～6.0 in weight from the results of 700℃ heating followed by hydrochloric acid treatment of the concrete

Investigation of old Building Concrete (11. Two Gymnasiums 28 Years old)

Natrium chloride concentration in concrete from sea environment can be the cause of the deterioration of reinforced concrete building， as well as the carbonation of the hydrated cement. The paper reports the results of investigations of two reinforced concrete gymnasiums， named K gym. and N gym. They are located at coastal area of Japan Sea in Hokuriku district of central Japan. The distance from the seashore are 800 meters and 4 kilometers respectively. The carbonation penetrated through finish mortar(1 cm thick) into concrete 1.2 cm at outside and 2.9 cm (without mortar) at roomside in K gym. And ln N gym，the carbonation was limited to the finish mortar (1.2 cm thick) at outside and 1.9 cm (without mortar) at roomside. In K gym，the maximum NaCl concentration in concrete wall was found at surface and it decreased at inner portion. The va1ue at 3 cm from the concrete surface (typicalconcrete cover for the reinforcing steel) was 0.066 % of sand weight， 1.6 times larger than the allowab1e limit specified in Japanese Architectural Standard Specification for the sea sand usage. While the value at N gym. was found to be 0.01 percent

Occurrence and Distribution of Aeromonas in Surface Water and Algae in River

太田川水系および小田川水系を選んで生活用水源あるいは内水面漁場としての河川水中におけるAeromonasの分布状況について調査し検討した。その結果, (1) Aeromonasは表流水中よりもアユなどの餌ともなる苔類にはるかに多く分布していた。 (2) この分布状況は水温に大きく影響され,27℃以上の温度域では試料の80%において1mlあたり10^3以上の菌数が存在し,水温の低下と共に減少する傾向を示した。 (3) この減少傾向は表流水で顕著で,20℃以下では1mlあたり10以下まで減少した。 (4) 分離されたAeromonasの病原性と密接な関係にある溶血能も,やはり水温に影響され,特に29℃以上では病原菌としての可能性を思わせる強い溶血能を持った菌株が60～80%を占めていた。 (5) しかし,水温の低下に伴って溶血能の弱い菌株や非溶血株が増える傾向にあった。Aeromonas (A. hydrophila, A. salmonicida etc.) are well known as being Vibrio associated with food poisoning or diseases among humans, fish including ayu (sweetfish) and other animals. The summer in 1978, a large number of Ayu died of illness in the Ohta river. At that time we examined and discussed the distribution of Aeromonas in the Ohta and Oda rivers. 1) Larger quantities of Aeromonas were distributed in algae which are Ayu and other fishes food than in the surface water itself. 2) The distribution of the Aeromonas depended on the water temperature largely. In 80% of the algae tested, the number of Aeromonas was 10^3 cells per ml in the temperature range of over 27°C. This number decreased gradually as the temperature decreased. 3) The decreasing tendency of Aeromonas was notable in the surface water. The number of Aeromonas per ml was less than 10 cells in the temperature range of below 20°C. 4) The haemolytic activity of the isolated Aeromonas also depended on the water temperature. Especially, in the temperature range, of over 29°C, 60-80% of the isolated Aeromonas had strong haemolytic activity which is connected with the cause of food poisoning or diseases among humans, fish and other snimals. 5) However, as the temperature decreased, the isolated Aeromonas had weak haemolytic activity. Still others had no haemolytic activity increased tendencies

Influence of Temperatures on Enterococci in the Presence of Sodium Chloride

食品の加工,貯蔵のための物理的,化学的処理に伴なって,食品中に存在する微生物がどのような影響を受けるかを推察する目的で,今回は腸球菌を用いて比較的高い濃度のNaClの存在下における温度感受性を検討した.その結果,①低温域(0°C以下)では死滅を律速する要因はNaCl濃度変化よりもむしろ温度変化に大きく依存することが判った. ②低温域における腸球菌の死滅は速度の異なる2種類の一次反応から成り,k1に依存することが判った. ③低温処理したS. faecium (A)はNaN3に対して強い感受性を示した.The influence of sodium chloride on the growth of enterococci (S. faecium A and B, S. faecalis and S. faecalis var. liquefacience) has been examined. The rate of extinction depended on the temperature more than on the sodium chloride concentration and a kinetic mechanism which qualitatively accounted for the observed behavior was discussed under the lower temperature zone (below 0℃). The reaction consisted from two kinds of velocities (k1 and k2) and depended on k1 grately. Cold- and frozen-injured S. faecium (A) in the presence of 6% sodium chloride was influenced by sodium azide.本研究の一部は第24回日本食品衛生学会(昭和47年,秋田)において発表した

Sublimation Behavior of Annular Frost Layer by Impinging Jet Flow

The present paper deals with a new method of defrosting using the frost sublimation phenomenon, which occurs below the triple point of water (273.16K, 610.5Pa). The present experimental study examines the mass transfer of the annular frost layer developed on a cooling pipe exposed to an impinging jet flow. The morphology of the frost layer during sublimation was observed using a digital video recorder. It was understood that the mass flux of the frost layer increased with increasing the jet flow velocity and the difference in the mass concentration of water vapor between the frost surface and the impinging jet flow. The non-dimensional correlation equations of mass transfer of defrosting were derived as functions of various parameters.</p

Improved controllability of wet infiltration technique for fabrication of solid oxide fuel cell anodes

Ni/yttria-stabilized zirconia anodes of solid oxide fuel cells are fabricated by a wet infiltration technique and the ability of the infiltration technique to control the anode microstructure is quantitatively demonstrated by a detailed three-dimensional microstructural analysis. The microstructural analysis reveals favorable aspects of the infiltrated anodes, such as larger triple-phase boundary density and sufficiently large pore size, and they are mostly unachievable by the conventional powder-mixing and sintering approaches. The improved controllability of the infiltration technique is expected to be useful to tailor porous microstructures to meet the multiple requirements for transport and electrochemical reactions within the anodes

On the Contamination of Sea Water with Salmonella and Fecal Indicator Organisms : II. Changes of Salmonella in Natural and Aseptic Sea Water

海域に流入したサルモネラが,どのような挙動を示すか,その動態を追究する目的で自然海水および無菌海水中でのモデル実験を行なった。 1: 自然海水中では接種したサルモネラは10℃>20℃>30℃の順に生残性を示した。 2: 無菌海水中ではサルモネラの生残性は自然海水中におけるよりも低く,しかもはっきりとした温度依存性を示さなかった。 3: 少量(<10/mlのサルモネラを接種した場合には,菌接種後,一度菌数が減少し,その後次第に増加した。 4: その場合,20℃および30℃に保持するとS.thompson単独例よりもE.coliとの混合例の方がS.thompsonの増殖する割合は低かった。 5: 海水中でのサルモネラの生残性は水温にかなり影響されることが示唆された。For the observation of behavior of Salmonella in sea water, the survivability of Salmonella inoculated in natural or aseptic sea water was examined. 1. In natural sea water, both S. anatum and S. thompson survived at the rate of 10C, 20C and 30C. 2. In sea water filtrated by a millipore filter, the temperature dependences of Salmonella were indefinite, and their survival periods were shorter than in natural sea water. 3. When some S. thompson (less 10 cells per ml.) has been inoculated into autoclaved sea water, their number decreased first and then increased gradually. 4. At this time, when the sea water was kept at 20C and 30C, the rate of multiplication of S. thompson mixed with E. coli was lower than that in the case of S. thompson alone. 5. The survivability of Salmonella in sea water depended considerably on the temperature.本研究の一部は昭和50～51年度文部省科学研究費(特定研究1「瀬戸内海の汚染と指標生物の動態に関する研究－代表者,藤山虎也教授」)によるものである

Effect of Aggregate Components on the Bond Strength and the Strength of Mortar

The report deals with the effect of chemical components of aggregate on the bond strength and the strength of mortar under three practical curing conditions (28 days in 20℃ water， 4 hours in 70℃ steam and 4 hours autoclave in 180℃ and 10 kg/㎠ ). Four typica1 rocks (quartzite， 1imestone， Taishufeldspar and India fe1dspar) and a blast-furnace slag were tested. The bond strengths in 20℃ or 70℃ curings werenearly the same but in autoc1ave， 1imestone， India fe1dspar and slag showed very low strength. It is shown also that the bending，compressive and sp1it-tensi1e strengths of 1imestone and India feldspar mortar specimens were remarkably lowered in autoclave curing. Scanning electron microscope observation showed that the surface of 1imestone and India fe1dspar were fissured and fine1y wrink1ed， suggesting the physica1 and chemica1 deterioration in autoclave. And it is assumed to be the cause of the low strength. Five kinds of crushed sand in market were also tested. The difference of mortar strengths between these aggregates were very small in 20℃ or 70℃ curing. In autoclave curing， however， two kinds of sand with higher SiO2 content showed higher strength. It is indicated by the present study that se1ection of curing appropriate to each aggregate was important to the effective production of concrete