Tetsu-to-Hagane
Online ISSN : 1883-2954
Print ISSN : 0021-1575
ISSN-L : 0021-1575
Volume 89 , Issue 4
Showing 1-19 articles out of 19 articles from the selected issue
  • Mitsutaka HINO
    2003 Volume 89 Issue 4 Pages 381
    Published: April 01, 2003
    Released: May 29, 2009
    JOURNALS FREE ACCESS
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  • Takayuki FUTATSUKA, Kiyoteru SHITOGIDEN, Takahiro MIKI, Tetsuya NAGASA ...
    2003 Volume 89 Issue 4 Pages 382-387
    Published: April 01, 2003
    Released: May 29, 2009
    JOURNALS FREE ACCESS
    Suppression of CO2 and slag discharged from iron- and steelmaking processes are some of the typical biggest issues for the protection of global environment and sustainable growth of steelmaking industry. Utilization of active phytoplankton propagation will be one of the best options, to stabilize and reduce carbon dioxide with great efficiency.
    Inorganic minerals such as C, N, Si, P, and Fe are necessary, for phytoplankton to grow. It is crucial for effective supply of nutrition to understand the dissolution mechanism of elements from steelmaking slags into seawater. At first, the morphology of the precipitated phases in steelmaking slags during cooling period was investigated in the present work. It was continued to compare the dissolution behavior of some elements from steelmaking slags and pure substances such as 4CaO P2O5, 3CaO·P2O5 and 2CaO·SiO2-3CaO·P2O5 (2.8 mass% P) solid solution phase into artificial seawater for understanding their dissolution possibility.
    The dissolution behavior of elements such as phosphorus are strongly dependent of phase present in steelmaking slag. It was confirmed that the dissolution of component in steelmaking slag was observed such that enough amount of nutrition for phytoplankton multiplication can be supplied from steelmaking slag.
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  • Takahiro MIKI, Kiyoteru SHITOGIDEN, Yusuke SAMADA, Tetsuya NAGASAKA, M ...
    2003 Volume 89 Issue 4 Pages 388-392
    Published: April 01, 2003
    Released: May 29, 2009
    JOURNALS FREE ACCESS
    Stability diagrams for Ca, Mg, CO2, P, Si, Fe and F in seawater have been estimated to understand the dissolution behavior of steelmakingslag constituents into seawater as nutrition for phytoplankton propagation. Dissolution behavior of each element from crystal phase present in steelmaking slags into seawater has been discussed based on the stability diagram. The presence of 4CaO·P22O5phase in steelmaking slag is preferred for effective phosphorus dissolution into seawater. Increase of pH value by Ca elution and buffering action of Mg in seawater against it have been clearly explained by using stability diagram. Elution behavior of environmentally restricted elements from steelmaking slag into seawater was also estimated. It was confirmed that stability diagram was a powerful tool to understand dissolution behavior of steelmaking slag.
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  • Hitoshi NAKATA, Manabu YAMAUCHI, Yoshiaki MORINISHI, Kaoru MASUDA
    2003 Volume 89 Issue 4 Pages 393-400
    Published: April 01, 2003
    Released: May 29, 2009
    JOURNALS FREE ACCESS
    For the purpose of reducing CO2 contents in the atmosphere, one of the solution is said to grow the biomass of phytoplankton by it's photosynthesis, that is enhances it's biological pump. When steelmaking slag is applied to the sea, the nutrient like phosphate and silicate, and ferrous ion as a micro nutrient, which is indispensable for the growth of phytoplankton, especially diatoms, is considered to be supplied sufficiently.
    This time, large tank test adding steelmaking slag was carried out, and increase behavior of phytoplankton was investigated. And at the same time, the behavior of various kinds of chemical elements which dissolves from steelmaking slag to the sea water examined in detail.
    The results show that contamination problems from the steelmaking slag which was applied to this experiment cannot be recognized. Behavior of dissolved element is compared to some experimental systems, for example, large tank test and beaker test etc., using analytical model. Furthermore, three dimensional simulation of dissolved nutrients from steelmaking slag was also investigated.
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  • Shigeaki TONOMURA, Satoshi TABUCHI
    2003 Volume 89 Issue 4 Pages 401-406
    Published: April 01, 2003
    Released: May 29, 2009
    JOURNALS FREE ACCESS
    The kinetic study on the CO2 sequestration using the steelmaking slags are executed. Optimum feeding rate of slag must be determined by taking into account the plankton multiplication and the mass balance. Based on this kinetics, feasibility study of CO2 sequestration by steelmaking slag, especially from logistic view point, is carried out, and the cost of this process is compared and discussed with conventional chemical absorption method.
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  • Atsushi HIRAYAMA, Manabu IGUCHI
    2003 Volume 89 Issue 4 Pages 407-414
    Published: April 01, 2003
    Released: May 29, 2009
    JOURNALS FREE ACCESS
    A model study was carried out to understand the dispersion of slag particles in the sea, which were introduced onto its surface as a nutritional source for CO2 fixation with marine phytoplankton multiplication. A mixture of water and fine particles was introduced onto the surface of a water bath using an acrylic pipe. The fine particles were used to decrease the falling velocity to a very low level. The behavior of them in the bath was observed with a CCD camera and a high-speed video camera. They dispersed suddenly on the bath surface just after the attachment of the mixture to the bath surface due to the surface tension force. The falling patterns of them were depended on the initial concentration of the mixture and basically classified into three types. The dispersion in the horizontal direction became greatest at a certain initial concentration. An optimum initial concentration therefore exists for uniform dispersion of fine particles in the bath.
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  • Koichi ARITA, Yasuyuki UMIGUCHI, Akira TANIGUCHI
    2003 Volume 89 Issue 4 Pages 415-421
    Published: April 01, 2003
    Released: May 29, 2009
    JOURNALS FREE ACCESS
    Steelmaking slag contains essential elements for growth of marine phytoplankton, such as iron, phosphorus and silicon. If these elements can be available for phytoplankton in seawater, the slag can be used as a fertilizer in marine environment. In this study, growth rates of the marineplanktonic diatom Thalassiosira guillardii were determined under enrichment with the slag to confirm the availability of these elements in seawater. The medium used in the growth experiments was a modified ESAW medium, in which a powdered decarburization steelmaking slag was added. The growth response of the diatom was determined by changed in vivo chlorophyll a fluorescence. The results suggest that the decarburization steelmaking slag can be an effective source of nutrients for marine phytoplankters.
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  • Koichi ARITA, Yasuvuki UMIGUCHI, Akira TANIGUCHI
    2003 Volume 89 Issue 4 Pages 422-429
    Published: April 01, 2003
    Released: May 29, 2009
    JOURNALS FREE ACCESS
    Availability of the elements originated from decarburization steelmaking slag, such as iron, phosphorus and silicon, was confirmed in the previous part of this paper. However, the slag does not contain nitrogen. On the other hand, treated urban sewage is rich in ammonic nitrogen, while relatively poor in phosphorus. In this part, combined effect of the slag and the sewage on growth of the marine planktonic diatom Thalassiosira guillardii was tested. Media used in the growth experiments were modified ESAW media, in which the powdered slag and/or the sewage were/was added. Growth response of the diatom was determined by changed in vivo chlorophyll a fluorescence. The results obtained suggest that, although the combined effect is usually significant, the availability of the elements can sometime be reduced under a certain experimental condition.
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  • Koichi HARAGUCHI, Akira TANIGUCHI
    2003 Volume 89 Issue 4 Pages 430-437
    Published: April 01, 2003
    Released: May 29, 2009
    JOURNALS FREE ACCESS
    Human activities have increased an input of nitrogen to coastal waters. Hyper nitrogenous and phosphorous limiting condition induces red tides of harmful algae which can vitally grown on a wide variety of phosphorous compounds. Environmental quality there is then reduced by altered phytoplankton composition. We hypothesize that such hyper nitrogenous condition can be turned into healthy eutrophic condition, where desirable phytoplankton assemblage can grow, by use of a steelmaking slag as a source of phosphate and silicate. We examined the effect of enrichment of the dephosphorization slag on a natural phytoplankton assemblage in the hyper nitrogenous water with treated municipal sewage. The enrichment enhanced phytoplankton growth particularly of diatoms, such as Skeletonema costatum, while excess enrichment (200 mg/l) suppressed phytoplankton growth probably due to pH increase and/or ammonia toxicity (un-ionized NH3 form) appeared under increasing pH. These results indicate that slag enrichment would be effective at lower dose to avoid pH increase. Although 20 mg/l slag and 20% sewage was confirmed to be the best dose at 10°C, the dose should be reduced during summer since the percent NH3 increases with temperature.
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  • Yasue NAKAMURA, Tomoki SATO, Kiyoteru SHITOGIDEN, Yoshihisa SAITO, Hit ...
    2003 Volume 89 Issue 4 Pages 438-445
    Published: April 01, 2003
    Released: May 29, 2009
    JOURNALS FREE ACCESS
    Responses of phytoplankton to the enrichment with steelmaking slags, de-Si and de-P slags, were determined by culture experiment in largvolume outdoor tanks. In the first series, chlorophyll-a concentration attained its maximum on the 11th or 12th day, whereas on the 4th or 5th day in the second series. After the maximum, cultures became nitrogen limiting in every treatment, indicating that both de-Si and de-P slags cannot supply nitrogen while phosphate and silicate can be supplied. Change in size composition was also observed for phytoplankton enriched with slags: larger fraction (> 10 μm) became dominant over smaller fraction (< 10 μm). These results indicate that elements such as P, Si and Fe released from the slags are available for phytoplankton.
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  • Yasue NAKAMURA, Akira TANIGUCHI
    2003 Volume 89 Issue 4 Pages 446-453
    Published: April 01, 2003
    Released: May 29, 2009
    JOURNALS FREE ACCESS
    In two series of the culture experiments to observe responses of a natural phytoplankton assemblage to enrichment with different steelmaking slags, de-Si slag and de-P slag temporal change of the assemblage in abundance and taxonomic composition was recorded. Phytoplankton chlorophyll a and abundance of diatoms attained their maxima on the 13th day in the first series, whereas on the 5th day in the second series. Among diatoms Skeletonema costatum was benefited most strikingly by the enrichments, particularly with the de-P slag. After the maxima, phytoplankton and diatoms as well readily decreased without forming a stationary state. Such a rapid initiation of decrease might be cased by the following three reasons, which were not directly caused by the slag enrichment. 1) Grazing by microheterotrophs such as amoebae, 2) physiological death caused by severe nitrogen depletion, and 3) sinking accelerated by coagulation with, fibrous exudate and filamentous bacteria.
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  • Hisahiro MATSUNAGA, Masato TAKAGI, Fumio KOGIKU
    2003 Volume 89 Issue 4 Pages 454-460
    Published: April 01, 2003
    Released: May 29, 2009
    JOURNALS FREE ACCESS
    Block without cement and natural aggregates has been developed from steel slag, and its applicability to marine structure has been investigated. The slag block has the following feature: (1) Similar-manufacturing process to conventional concrete can be used. (2) It has sufficient strength to adapt the standard of marine concrete. (3) It has excellent abrasion resistance characteristics. (4) The lower rate of dissolution of alkaline elements in soaking seawater. (5) The biofouling growth on slag block was significantly more than that on the concrete block in the intertidal area at Mizushima Port in the Inland Sea. This was true both with respect to the total biomass of biofouling organisms as well as the number of species.
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  • Hirohiko SASAMOTO, Akira TSUBONE, Yasuhiko KAMIYA, Kazuya SANO
    2003 Volume 89 Issue 4 Pages 461-465
    Published: April 01, 2003
    Released: May 29, 2009
    JOURNALS FREE ACCESS
    The steel-making slag in the EAF industry is generated 3.2 million t/year in the Japanese whole as a waste. The most of the steel-making slag are aging, and are used as a roadbed material. But, recently those futures are very severe situation by the rivalry with the use of construction waste materials. Therefore that promoted the theme of the development of the fishing block using refining slag', because it was a pressing need to aim for high value added-ization in the above now.
    It found out the following as that result.
    (1) The block which made the ATK cement mixed plaster with refining slag powder have a good properties as a base material.
    (2) The leaching of the iron ion was effective in the growth of the marine organisms, and it could get a good result by this iron ion being leached, when oxidizing slag was applied to the fishing block.
    (3) CO2 emission in Portland cement manufacture doesn't only become a "zero", but also this block fixes CO2 through the marine organism's growth, and it can be said as the effective block from viewpoint of a decrease in CO2.
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  • Norikazu HIROSE, Shigeru MONTANI
    2003 Volume 89 Issue 4 Pages 466-471
    Published: April 01, 2003
    Released: May 29, 2009
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    Mortality on a mass scale in pearl oyster farming has been considered a serious problem in Japan since 1996, due to food shortage and resulting infection. The authors have developed a diatoms feeding system for pearl oysters to alleviate this. A study was conducted to inhibit the problem and tries to increase and maintain diatoms density by supplementing diatoms for pearl oysters in a rehabilitation water tank in Uwajima, Ehime Prefecture from the spring to summer of 1999 and 2000.
    The results show that the diatom density, feces excretion of the pearl oysters and feeding volume uptake were all higher in the rehabilitation water tank compared to outside in the sea. The system improved on the food shortage condition. There is potential here for the prevention of mass mortalities in pearl oysters using the system.
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  • Masahiro HATA
    2003 Volume 89 Issue 4 Pages 472-474
    Published: April 01, 2003
    Released: January 15, 2010
    JOURNALS FREE ACCESS
    Marine brown algal polysaccharides, especially, fucoidans and laminaran have many biological activities (anticoagulant, antithrombotic, antiviral, and antitumoral). These biological activity related to structure, linkage of sugar residues, sulfate content, position of sulfate and molecular size. Shorter bioactive polymer (higher oligomer) could be obtained by enzymatic depolymerization process. Lytic enzyme β-1, 3-glucanases hydrolyze laminaran
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  • Hiroko SAKAMOTO, Hideyuki TORADA, Kentaro GOTO, Yasue NAKAMURA, Toshik ...
    2003 Volume 89 Issue 4 Pages 475-481
    Published: April 01, 2003
    Released: May 29, 2009
    JOURNALS FREE ACCESS
    Marine phytoplankton Porphyridium sp. produced and secreted a mucilaginous polysaccharide in the incubation medium. The polysaccharide production was enhanced by the addition of slag at proper concentration. This polysaccharide showed a moderate mitogen activity, similar to dextran sulfate but lower than concanavalin A and lipopolysaccharide. Polysaccharide was found to have antitumor activity against Sarcoma 180 inoculated in the peritoneal cavity of ddY mice.
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  • Tamiji YAMAMOTO, Masami SUZUKI, Seok Jin OH, Osamu MATSUDA
    2003 Volume 89 Issue 4 Pages 482-488
    Published: April 01, 2003
    Released: May 29, 2009
    JOURNALS FREE ACCESS
    Some coastal seas in post-industrialized countries are in the process of oligotrophication as a consequence of a rapid reduction in the load of certain nutrients such as phosphorus. Much worse is that this can sometimes be accompanied by noxious phytoplankton blooms due to an imbalance in the elemental ratio in seawater. Oligotrophication also leads to a reduced fishery production through a decrease in primary production and a change in community structure of the ecosystem. Slag produced as a waste bi-product during steelmaking, contains significant amounts of phosphorus and silicon. Both phosphorus and silicon form nutrient salts, phosphate and silicate, which enhance the growth of marine phytoplankton. Experimental studies were carried out to measure both the release of phosphate and silicate from steelmaking slag, and the increase of the growth rate of natural marine phytoplankton assemblages from this release. The appropriate concentration of slag addition for the growth of phytoplankton was considered to be around 100 mgl-1 among the concentrations set in the present study, because sufficient growth was not obtained with 50 mg l-1, and sharp increase in pH with 500 mgl-1 addition inhibited the growth of phytoplankton. Diatom was the taxonomic group dominated in cell numbers after the addition of the slag. Silicate released from the slag appeared to support the growth of this group. In the group of diatoms, the growth response was different for individual species, suggesting that the species which will appear as a result of slag addition could be controlled with the characteristic and amount of slag applied. Discussion is made on the importance of controlling the coastal seas to conserve the precious coastal marine ecosystems as we have done so in rural areas of terrestrial ecosystems where human and nature coexist.
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  • Yoshiharu NAKAMURA
    2003 Volume 89 Issue 4 Pages 489-493
    Published: April 01, 2003
    Released: May 29, 2009
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    Several problems concerning the relationship between the demand and supply of fishery products in Japan are outlined in this study. Interactions between ecological functions of the coastal areas known as fishing grounds, and four fishery production processes (the cultivation fishery, the resource management type fishery, the coastal fishing ground development practice, mariculture) are summarized. In addition, this study describes the framework of the technical combination surrounding fishery researches. From views of fisheries that are responsible for the stable supply of safe fishery products, the ecologically compatibility production method is structured into three types (the symbiosis type, the compatible type, the conservation type). Ecological explanations are also provided to describe each type of the method. Further, management objectives and standards are proposed for the sustainable fishery production by effectively utilizing structural characteristics of an ecosystem, and notable issues raised at production settings are outlined. Lastly, a functional evaluation model necessary as a guideline for the protection of fishing environments and for the sustainable production is classified and roles of the model are summarized.
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  • Tamiji YAMAMOTO
    2003 Volume 89 Issue 4 Pages 494-496
    Published: April 01, 2003
    Released: May 29, 2009
    JOURNALS FREE ACCESS
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