Fukken Co.

Ōsaka, Japan

Fukken Co.

Ōsaka, Japan
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Adachi N.,Naruto University of Education | Asada Y.,Fukken Co. | Ezaki Y.,Osaka City University | Liu J.,Peking University
Palaeogeography, Palaeoclimatology, Palaeoecology | Year: 2017

Stromatolites just after the end-Permian extinction are exceptionally well developed in the Chongyang area of Hubei Province, South China. The stromatolites include endolithic coccoidal microbes and exhibit three growth forms: columnar-layered, pseudo-columnar, and columnar, each located in different stratigraphic horizons. The columnar type is the most conspicuous and provides key information on the mode of their construction. In this paper, we describe the mega- to microscopic features of these stromatolites together with interpretations of their construction. The columnar type typically comprises alternations of lighter and darker laminae with intercalations of dense micritic laminae. The lighter laminae are composed of fine to coarse calcite cement and fine dolomite, whereas the darker laminae are composed of micrite and microspar. Endolithic coccoids are sporadic in these laminae. In contrast, the dense micritic laminae consist of micrite with abundant endolithic coccoids, accentuating the laminae of stromatolites. The columnar stromatolites were formed under deteriorating conditions after the end-Permian mass extinction as follows: (1) the alternating development of lighter and darker laminae due to the colonization of different microbial communities in lower-energy, shallow- to deep-subtidal settings; (2) carbonate precipitation within each microbial community through microbial metabolic activity and degradation of extracellular polymeric substances (EPS), leading to the alternations of lighter and darker laminae; (3) episodic interruption of the growth of the lighter and darker laminae by endolithic coccoidal activity; and (4) high levels of endolithic activity, accompanied by the precipitation of carbonate within boreholes to produce the dense micritic laminae. In contrast, the columnar-layered and pseudo-columnar types comprise alternations of lighter and darker laminae, composed mainly of fine to coarse calcite cement, fine dolomite, micrite, peloids, and microspar with sporadic endolithic coccoids. The dense micritic laminae are absent or rare in these stromatolites. These types were essentially produced by the repetition of processes (1) and (2) documented in the columnar type. The finely alternating laminae of these stromatolites are therefore the product of the repeated initiation and cessation of growth of relevant microbial communities in response to changing environmental conditions. The stromatolites were formed immediately after the end-Permian extinction and persisted intermittently throughout the Early Triassic. The Chongyang stromatolites are undoubtedly some of the best-developed stromatolites near the Permian–Triassic boundary and retain a high-resolution record of microbial successions and palaeo-oceanic perturbations immediately following the end-Permian extinction. © 2017 Elsevier B.V.


Tsuchida T.,Hiroshima University | Kano S.,Kure National Technical College | Nakagawa S.,West Corporation | Kaibori M.,Hiroshima University | And 2 more authors.
Soils and Foundations | Year: 2014

The collapse of a filling occurred due to heavy rain in Higashi-Hiroshima Citys Shiwa District at about 5:30 am July 25th, 2009. The filling was made of surplus soils, and it contained a mass of water supplied from rainfall and ground water flow of a permeable layer at the bottom of the filling. The collapsed soil flowed down and destroyed a house. In this paper, the cause of this disaster is discussed. The site of the disaster was used as the dumping site of surplus soils, after several changes of ground formation. The history of the geographical change was reconstructed by the image processing of old map, aerial photographs, result of 3-dimentional laser survey carried out after collapse and the measurement of thickness of collapsed soil by dynamic cone penetration test. According to the result of processing, the shape and the size of the filling before collapse was reconstructed. The relationship between the rainfall and the groundwater in the river sediments layer over which the filling was constructed was determined. A stability analysis of the filling was conducted considering the rise of the groundwater level in the filling and the laboratory measured strength parameters. The results of the stability analysis showed that the collapse would have taken place when the groundwater level rose by about 9 m due to the supply of groundwater through the river sediments layer. © 2014 Japanese Geotechnical Society.


Kim K.,Hiroshima University | Hibino T.,Hiroshima University | Yamamoto T.,Hiroshima University | Hayakawa S.,Hiroshima University | And 3 more authors.
Marine Pollution Bulletin | Year: 2014

Field experiments were carried out to evaluate the effect of Granulated Coal Ash (GCA) on remediation of coastal sediments in terms of removing phosphates and hydrogen sulfide. Phosphate concentrations in the sediment were kept below 0.2mg/l after the application of GCA, whereas those in the control sites increased up to 1.0mg/l. The concentration of hydrogen sulfide in the sediment was maintained at almost zero in the experimental sites (GCA application sites) for over one year, whereas it ranged 0.1-2.4mgSL-1 in control sites. Meanwhile, individual number of benthos increased in the experimental sites by several orders of magnitude compared to the control sites. The major process involved in hydrogen sulfide removal by GCA was thought to be the increase in pH, which suppresses hydrogen sulfide formation. From our findings, we concluded that GCA is an effective material for remediating organically enriched coastal sediment. © 2014 Elsevier Ltd.


Yamamoto H.,FUKKEN Co. | Yamamoto T.,Hiroshima University | Mito Y.,FUKKEN Co. | Asaoka S.,Kobe University
Marine Pollution Bulletin | Year: 2016

Granulated coal ash (GCA), which is a by-product of coal thermal electric power stations, effectively decreases phosphate and hydrogen sulfide (H2S) concentrations in the pore water of coastal marine sediments. In this study, we developed a pelagic-benthic coupled ecosystem model to evaluate the effectiveness of GCA for diminishing the oxygen-deficient water mass formed in coastal bottom water of Hiroshima Bay in Japan. Numerical experiments revealed the application of GCA was effective for reducing the oxygen-deficient water masses, showing alleviation of the DO depletion in summer increased by 0.4-3 mg l-1. The effect of H2S adsorption onto the GCA lasted for 5.25 years in the case in which GCA was mixed with the sediment in a volume ratio of 1:1. The application of this new GCA-based environmental restoration technique could also make a substantial contribution to form a recycling-oriented society. © 2016 Elsevier Ltd.


PubMed | Hiroshima University, FUKKEN Co. and Kobe University
Type: Journal Article | Journal: Marine pollution bulletin | Year: 2016

Granulated coal ash (GCA), which is a by-product of coal thermal electric power stations, effectively decreases phosphate and hydrogen sulfide (H2S) concentrations in the pore water of coastal marine sediments. In this study, we developed a pelagic-benthic coupled ecosystem model to evaluate the effectiveness of GCA for diminishing the oxygen-deficient water mass formed in coastal bottom water of Hiroshima Bay in Japan. Numerical experiments revealed the application of GCA was effective for reducing the oxygen-deficient water masses, showing alleviation of the DO depletion in summer increased by 0.4-3mgl(-1). The effect of H2S adsorption onto the GCA lasted for 5.25years in the case in which GCA was mixed with the sediment in a volume ratio of 1:1. The application of this new GCA-based environmental restoration technique could also make a substantial contribution to form a recycling-oriented society.


Suzuki H.,Tokushima University | Okano Y.,Fukken Co.
Unsaturated Soils: Research and Applications - Proceedings of the 6th International Conference on Unsaturated Soils, UNSAT 2014 | Year: 2014

Terzaghi (1948) had established soil mechanics as an academic scholarship due to the discovery of the principal of effective stress for saturated soils when he considered the consolidation theory of saturated clay. The reason of the existence of the effective stress is that soil particles composite of incompressible solid and water composite of incompressible liquid. Although air is very compressible fluid, the principle of effective stress is also used in unsaturated soils in the resent developed numerical analyses. Schrefler' equation (1984) is most frequently used, but the effective stress is not verified by the experimental results. In this study, the equations for unsaturated soils proposed by Schrefler (1984), Aitchison (1960), Khalili & Khabbaz (1998) and Kohgo (1993) are compared with using the results of suction controlled consolidometer tests. As a result, the effective stress for unsaturated soils calculated by Schrefler' equation were average of them. © 2014 Taylor & Francis Group, London.


Suzuki H.,Tokushima University | Okano Y.,Fukken Co.
Unsaturated Soils: Research and Applications - Proceedings of the 6th International Conference on Unsaturated Soils, UNSAT 2014 | Year: 2014

It is too difficult for a compacted specimen of unsaturated clay prepared and used in a laboratory test to have homogeneous water content and porosity. Although there have been many hydraulic and mechanical studies, there are few papers related to homogeneity of specimen. However, it is clear that homogeneity of specimen influences mechanical properties. In this paper, the use of micro-waves is proposed as method for making homogeneous specimens. The study results indicate that specimens made by micro-waves are more homogeneous than compacted specimens. © 2014 Taylor & Francis Group.


Asakura H.,Fukken Co. | Matsuto T.,Hokkaido University | Inoue Y.,Japan National Institute of Environmental Studies
Waste Management and Research | Year: 2010

In Japan, as the construction of new landfill facilities has become extremely difficult and the number of sites procured for landfill construction has decreased due to the not in my back yard (NIMBY) syndrome, it has been assumed that the adoption of new technologies has increased. As the performance of new technologies exceeds that of conventional technologies, it is also assumed that residents would prefer the use of these new technologies and therefore any construction plans should be devised to ensure their use to ensure residents satisfaction. In the present study, the technologies adopted for municipal solid waste landfill facilities constructed in recent years (2000 to 2004) in Japan and the bases for their adoption were investigated by means of a questionnaire survey. One of the main bases for the adoption of new technologies was the request by residents for new technology for roofing, rather than the other for new technologies for barrier systems, leachate treatment, and monitoring. In addition, it is possible that the municipalities did not recognize the difference between conventional and new technologies as defined in this study. The roof-type landfill that isolates waste from the surrounding environment was one of the requirements for the construction of new landfill facilities identified in the present investigation, and in this regard waste isolation should be required in all circumstances. © The Author(s), 2010.


Watanabe S.,Fukken Co. | Hyodo M.,Yamaguchi University
Geomechanics from Micro to Macro - Proceedings of the TC105 ISSMGE International Symposium on Geomechanics from Micro to Macro, IS-Cambridge 2014 | Year: 2015

A series of undrained triaxial monotonic and cyclic tests were performed on sand and natural clay mixtures with various fines content. Monotonic and cyclic shear strengths were varied depending on their void ratio even if the fines content was identical for the material in which sand forms skeleton. A unique undrained monotonic and cyclic shear strengths dependent on fines content were observed in material where clay formed the matrix. Introduction of the concept of equivalent granular void ratio with a contribution factor for the fines of 0.3 resulted in a unique steady state line, undrained monotonic and cyclic shear strengths similar to that for pure sand. © 2015 Taylor & Francis Group.


Watanabe S.,Fukken Co. | Hyodo M.,Yamaguchi University
15th Asian Regional Conference on Soil Mechanics and Geotechnical Engineering, ARC 2015: New Innovations and Sustainability | Year: 2015

A large amount of reclaimed ground along Tokyo bay suffered damage due to liquefaction during the 2011 Great East Japan Earthquake. The liquefied areas were mostly concentrated in newly reclaimed land. The aging effect is considered to be important for the susceptibility of ground to liquefaction. The liquefied soils contained a lot of fines and the fines content varied by place. In this study, in order to understand the dynamic deformation characteristics of the ground, a series of bender element tests and hollow cylindrical torsional tests were performed on sand and clay mixtures with various proportions of fines content. Furthermore, the water content of the mixed clay was varied between the liquid limit and two times the liquid limit. The variation of water content of the clay in the sand-clay mixtures was considered to represent the effect of aging. Test results show that the maximum shear stiffness decreased with increasing fines content and water content of the clay3.

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