Nishinihon Institute of Technology

Japan

Nishinihon Institute of Technology

Japan

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Tran H.D.,Hanoi National University of Education | Kinoshita I.,Kochi University | Azuma K.,Nishinihon Institute of Technology | Iseki T.,Japan Sea National Fisheries Research and Development Center | And 2 more authors.
Environmental Biology of Fishes | Year: 2014

To examine regional specific diversity in development and growth of Ayu (Plecoglossus altivelis) larvae, we collected and compared collections from the Kalong estuary in Vietnam, and the Shimanto and Muko estuary, and the Niigata coast in Japan. Among the four areas, most of the morphometrics through ontogeny were similar except that the snout tended to be shorter and the anus hardly migrated in Kalong larvae. The snout length increased gradually with growth in the Vietnamese larvae, while this value increased significantly until ca. 10 mm BL, subsequently being constant up to 30 mm body length (BL) in the Japanese larvae. The water temperature when the larvae were collected was higher in the Kalong than in most of the Japan sites. Growth-rates estimated from otolith increments were from highest to lowest, Niigata (mean = 0.54 mm/day), Kalong (0.47), Shimanto (0.38) and Muko (0.34). The higher growth-rates were obtained not in Niigata of highest latitudinal region, but in Kalong of lowest latitudinal region. This indicates that Ayu could experience their early developmental stages from the cool temperate to tropical regions, implying the potential biodiversity of this fish species in the world. © 2014, Springer Science+Business Media Dordrecht.


Tran H.D.,Kochi University | Kinoshita I.,Kochi University | Ta T.T.,Vietnam National University, Hanoi | Azuma K.,Nishinihon Institute of Technology
Ichthyological Research | Year: 2012

The early life history of Ayu (Plecoglossus altivelis) was investigated in the Kalong and Tien Yen River systems, northern Vietnam, which is probably the most southern distribution locality for this species, during the period of November 2010 to February 2011. A total of 248 larvae were captured in the Kalong, and none were collected in the Tien Yen. There was little difference in development between the Kalong larvae and those of P. a. altivelis and P. a. ryukyuensis. Temperatures and salinities when the larvae were collected ranged from ca. 12 to 21°C and from ca. 3.5 to 30 psu. The preflexion to flexion larvae (primarily preflexion with yolk, 5.2-12.9 mm BL) occurred in the central current from December to February, with a peak abundance in early January. The flexion to postflexion (primarily postflexion, 14.1-23.8 mm BL) larvae occurred in the bank waters from early January to late February. The larval occurrence in the Kalong was 1-2 months later than for P. a. altivelis in Japan and P. a. ryukyuensis in the Ryukyu Islands, probably because of the delay until a reasonable photope-riod for the start of spawning in the lower latitudinal region. The larvae were never collected from the sea, where the temperatures were lower than in the river and estuary in January and February, unlike in Japan. © The Ichthyological Society of Japan 2012.


Morita Y.,Kochi Prefectural Industrial Technology Center | Morita Y.,Nishinihon Institute of Technology | Okazaki Y.,Kochi Prefectural Industrial Technology Center | Kawakita H.,Kochi Prefectural Industrial Technology Center | Sumida T.,Kochi Prefectural Industrial Technology Center
Bunseki Kagaku | Year: 2012

An analysis method for halogens in organic materials was examined by air combustion coupled with ion chromatography. In this system, a sample of 0.1-0.5 g was weighted and ignited slowly in a quartz combustion tube at 1000°C with air gas at a flow rate of 2.5 L min-1. The combustion products were collected into 20 mL of a 40 mM potassium hydroxide solution in which 20 μxL of 3% hydrogen peroxide was added for reducing. Halogens (F, Cl, Br) were determined by ion chromatography. Recoveries for the halogens tested were almost 100 ± 10%. The accuracy of the proposed method was evaluated by analyzing a standard reference material of polyethylene (NMIJ CRM8108-a, AIST Japan and ERM-EC680K, IRMM Belgium). The values of Br and Cl obtained with the present method showed good agreement with the certified values, as judged from standard deviation. The present method was also applied to proficiency testing for the determination of bromine in a plastic material. The analytical results for the z score were 0.199 (low con.) and - 0.597 (high con.). © 2012 The Japan Society for Analytical Chemistry.


Umetani T.,HINODE Ltd. | Takada H.,HINODE Ltd. | Ikeda T.,HINODE Ltd. | Yamaguchi T.,Kyushu Institute of Technology | And 2 more authors.
Yosetsu Gakkai Ronbunshu/Quarterly Journal of the Japan Welding Society | Year: 2013

The purpose of this study was to examine the weldability of Si-solution strengthened ferritic ductile cast iron (SSFDI: EN-GJS-500-14) compared with a traditional ferrite-pearlite type ductile cast iron of similar strength (JIS-FCD500-7). The α+graphite→γ reverse transformation characteristics on heating process and the transformation characteristics on cooling were investigated by synthetic weld thermal cycle method. Heating SSFDI at 300°C/s (200-800 °C), the reverse transformation started at 837 °C and finished at 1149 °C. The austenite arose around graphite nodules and the area fraction in matrix moderately increased to 100% as the temperature became higher. In the ferrite-pearlite type ductile cast iron FCD500 with 2.27%Si, the reverse transformation occurred in the temperature range from 763 °C to 1105 °C. The pearlite rapidly transformed to austenite and then the ferrite moderately transformed. The austenitization rate of SSFDI was also lower than the ferritepearlite type ductile cast iron at 1000 °C. In case of the cooling parameter t8/5=25s, the martensite area fraction increased as the maximum temperature rose. Less martensite appears in SSFDI, indicating arc welding would give rise to less brittle heat affected zone (HAZ) in SSFDI.


Umetani T.,Hinode Ltd | Takada H.,Hinode Ltd | Ikeda T.,Hinode Ltd | Yamaguchi T.,Kyushu Institute of Technology | And 2 more authors.
Welding International | Year: 2015

The purpose of this study was to examine the weldability of Si-solution-strengthened ferritic ductile cast iron (SSFDI: ENGJS-500-14) compared with a traditional ferrite-pearlite type ductile cast iron of similar strength (JIS-FCD500-7). The a þgraphite!g reverse transformation characteristics on heating process and the transformation characteristics on cooling were investigated by the synthetic weld thermal cycle method. Heating SSFDI at 300°C s-1 (200-800°C), the reverse transformation started at 8378C and finished at 1149°C. The austenite arose around graphite nodules and the fraction in the matrix moderately increased to 100% as the temperature became higher. In the ferrite-pearlite type ductile cast iron FCD500 with 2.27%Si, the reverse transformation occurred in the temperature range from 7638C to 11058C. The pearlite rapidly transformed to austenite and then the ferrite moderately transformed. The austenitization rate of SSFDI was also lower than the ferrite-pearlite type ductile cast iron at 1000°C. In the case of the cooling parameter t8/5 ¼ 25 s, the martensite area fraction increased as the maximum temperature rose. Less martensite appears in SSFDI, indicating arc welding would give rise to less brittle heat-affected zone un SSFDI. © 2014 Taylor & Francis.


Nigi G.,Nishinihon Institute of Technology | Fujita S.,Nishinihon Institute of Technology | Azuma K.,Nishinihon Institute of Technology Shimanto Research Center | Hiraga H.,Nishinihon Institute of Technology
Japanese Journal of Limnology | Year: 2014

To understand the change in runoff characteristics of turbid water generated by the large-scale landslides that occurred in the upstream areas of the Monobe River in August 2004 and September 2005, the period 2001 ~2011 was assessed. Data analyzed included the secular variation of the SPM (suspended particulate matter) load, the correlation between discharge and turbidity (C-Q relation), and the days when the water turbidity of the river was 10 mg L-1 and over during the river residence period (June to September) of the Ayu (Plecoglossus altivelis altivelis) in the lower reaches of the river. The SPM load, the rate of increase in turbidity during fl oods, and the days of turbidity 10 mg L-1 and over increased after the landslides occurred. These apparent increases due to the landslides were observed between 2004 and 2007. More recently, SPM loads in both 2010 and 2011 were less than 50% of those observed in 2006, although the annual precipitation in both 2010 and 2011 was larger than that in 2006. However, in recent years, the days of turbidity 10 mg L-1 and over have tended to increase again. This was especially apparent for 54 days recorded in 2011, which had the maximum values except for 70 days in 2006. It is clear that large scale landslides induce high water turbidity with long-term persistence. In recent years, the highly turbid water generation has declined gradually, whereas the generation of turbidity that can affect growth of the Ayu has increased. We found that the long-term persistence of turbid water is a severe recurring problem in the Monobe River. © 2014, Japanese Society of Limnology. All rights reserved.


Simanjuntak C.P.H.,Kochi University | Kinoshita I.,Kochi University | Fujita S.,Nishinihon Institute of Technology | Takeuchi K.,Wako
Ichthyological Research | Year: 2015

To examine reproduction of Coilia nasus, an engraulid endemic fish to Ariake Bay, in the freshwaters upstream of the reclamation dike of Isahaya inlet, ichthyoplankton was collected at the surface with a larva net. Eggs and larvae of this species were captured in abundance, especially in the retention basin. All eggs had reached middle or late embryonic stages, and larvae from the preflexion with yolk to the juvenile stage (4.1–39.3 mm) were found. This suggests that the freshwaters of retention basin supply spawning and nursery grounds for C. nasus. © 2014, The Ichthyological Society of Japan.


Yagi Y.,Kochi University | Kodono N.,Kochi University | Kinoshita I.,Kochi University | Fujita S.,Nishinihon Institute of Technology
Ichthyological Research | Year: 2010

Little is known about where anguilliform fishes complete metamorphosis from the leptocephalus to juvenile stage. Conger myriaster leptocephali in the final stages of metamorphosing were collected from the estuarine portions of the lower Rokkaku River and in the northwest region of Ariake Bay. Three metamorphosing leptocephali with PAM/TM ratios of 0.27-0.34 were collected in the lower river, and five (PAM/TM, 0.30-0.46) were collected at sea stations in the bay. The collection of metamorphosing larvae of this species in a river estuary with lower salinity and high turbidity raises the question of how much these habitats are used by the metamorphosing larvae of this marine eel species. © 2010 The Ichthyological Society of Japan.

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