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Volume 44 (1990)
- Issue 6 Pages 355-
- Issue 5 Pages 301-
- Issue 4 Pages 235-
- Issue 3 Pages 159-
- Issue 2 Pages 93-
- Issue 1 Pages 5-
Volume 44, Issue 6
Displaying 1-6 of 6 articles from this issue
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Ecological Study of a Thailand Mangrove Forest (1)Shigeru KATO, Somechai PANICHUSUKO, Toshihide NAGANO, Jiro SUGI1990 Volume 44 Issue 6 Pages 355-360
Published: 1990
Released on J-STAGE: February 19, 2013
JOURNAL FREE ACCESSThree research points were set in a mangrove forest at Phang Nga area of Southern Thailand. Under-ground water samples were collected in rainy and dry seasons and were analyzed for composition of ions ; the relationshipbetween ion components of under-ground water and mangrove plants (species) was examined.
The main ion components of each research point were Na+ ion and Cl-ion in both dry and rainy seasons ; secondary ion components were Mg2+ ion, Ca2+ ion, and SO42- ion. Na+ ion and Cl- ion of research point B, i.e., that nearest to the open sea area in this research, showed higher amounts than those of the other two research points, A and C.
Mangrove plant species of each survey point 1 of the 3 research areas were Avicennia sp. and Sonneratia sp. of high tolerance to NaCl. On the other hand, mangrove species of the inner survey areas of the mangrove forest were observed species of low tolerance to NaCl. NaCl concentration of under-ground water, the inflow of seawater to the mangrove forest, and the outflow of seawater and river water to the sea were considered to be important factors in the distribution of mangrove plants. Especially, Na+ ion and ion concentrations are important factors for the growth of each mangrove species in the mangrove forest. SO42- ion concentration of all research points was higher than the average SO42- ion concentration of sea water.View full abstractDownload PDF (4216K) -
Membrane Conversion Process of the Energy of Mixing (Part 4)Haruhiko OHYA, Seiichi WATANABE, Katsunori HIROISHI, Youichi NEGISHI1990 Volume 44 Issue 6 Pages 361-364
Published: 1990
Released on J-STAGE: February 19, 2013
JOURNAL FREE ACCESSA dialytic battery of flow type was constructed, having 81 compartments made with 40 pairs of cation and anion-exchange membranes, each having an effective area of 200 cm2 and a pair of AgAgCl electrodes at both ends as the anode and the cathode. Output electromotive force and current of the battery were measured with concentrated aqueous NaCl solution of 50-80g/l and diluted solution of 0.4-12g/l. The maximum output power of 0.5W was measured at the following conditions: concentration of the concentrated solution was 65g/l and that of the diluted one was 4g/l, and the resistance of the external load was 5Ω. The results obtained were well explained by considering internal circuits at conduit channels and the internal resistance of membranes and the diluted-solution compartments, and the reaction resistances at the both electrodes. An attempt was made to calculate a scale-up of a battery having 1,000 pairs of membranes of which the effective area is 0.1m2, ignoring the both effects of short circuit and the electrodes. As an example, the scaled-up battery may produce 150W of power between the sea water and the diluted sea water of one-tenth of concentration.View full abstractDownload PDF (2358K) -
Takeo HONDA1990 Volume 44 Issue 6 Pages 365-373
Published: 1990
Released on J-STAGE: February 19, 2013
JOURNAL FREE ACCESSOutput characteristics of alternative-tank-type and submarine-type PRO power generation systems were examined with simulated experiments using a tailor-made two-partitioned hollow fiber permeator. For design of the permeator and analysis of experimental results, estimate calculations were carried out previously. Net power output calculated from the experimental data was about four times greater than that of the conventional system (pressurized-seawater-type) Specific power output per membrane area and per feed fresh water were attained about 0.5W/m2 and 0.1kWh/m3, respectively.
Energy conversion efficiency depends on the type of generating system and the operating condition.However, analysis showed that flushing by fresh water and decrease of concentration difference across the membrane by permeate water induce relatively big power losses. And also, the concentration polarizations on the surface and in the substructure of the membrane, and the pressure losses in the fluid passages affect power losses. To decrease these power losses for practical application, use of clean fresh water, improvement of the membrane characteristics, and optimum design of the permeator are required.View full abstractDownload PDF (6194K) -
Yasuo MIYAKE, Katsuko SARUHASHI, Takeshi SAGI, Teruko KANAZAWA1990 Volume 44 Issue 6 Pages 374-379
Published: 1990
Released on J-STAGE: February 19, 2013
JOURNAL FREE ACCESSSilicate is an important nutrient in the sea. The result of observation of silicate content was obtained in 1971 aboard the observation vessel that belonged to Tokyo University. Using these results, the problem of silicate in the sea is discussed.
The concentration of silicate is small near the surface and increases with the depth. The total mean concentration of silicate is higher in the North than in the South Pacific. The relation between the apparent oxygen utilization and the content of nitrate, etc., is almost linear, but there is no regular relation with respect to silicate.
This shows that most of the silicate in the sea is produced by processes other than oxidation. In the sea, the residence time of silicate is about 10,000 years; however, due to the difference in the chemical properties, the mode of concentration of silicate in the sea is quite different from other nutrient elements.
The circulation of silicate content in the sea is also considered.View full abstractDownload PDF (3139K) -
Fumiyuki HANAFUSA1990 Volume 44 Issue 6 Pages 380-389
Published: 1990
Released on J-STAGE: February 19, 2013
JOURNAL FREE ACCESSDownload PDF (6004K) -
Toru HIDAKA1990 Volume 44 Issue 6 Pages 390-398
Published: 1990
Released on J-STAGE: February 19, 2013
JOURNAL FREE ACCESSDownload PDF (6192K)
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