• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.42 no.4
• /
• pp.373-379
• /
• 2009

This study investigated oxygen consumption rate (OCR), $Q_{10}$ coefficient and ammonia excretion rate of the greenling, Hexagrammos otakii Jordan et Starks with the average body weight of 250 g in a semi-recirculated respiratory measuring system. The experiment was done under three different water temperatures (10, 15, $20^{\circ}C$) and five different ambient ammonia concentrations (0, 2.5, 5, 10, 20 mg/L). As the water temperature and ambient ammonia concentration increased the OCR has significantly increased (P<0.05). Given experimental conditions, the OCR of greenling were $50.8{\sim}159.4\;mg\;O_2\;kg^{-1}\;hr^{-1}$ and the relationship of water temperature (T) and ambient ammonia concentration (C) on the OCR were following: OCR = 41.3 - 1.87T - 7.38C + $0.463T^2$ + $0.66lC^2$ + 0.642TC - $0.011T^3$ - $0.010C^2$ - $0.031TC^2$ - $0.001T^2$C ($r^2$= 0.9226). $Q_{10}$ coefficients were $1.88{\sim}3.50$ for $10^{\circ}C$ to $15^{\circ}C$, $1.03{\sim}2.73$ for $15^{\circ}C$ to $20^{\circ}C$ and $1.40{\sim}1.90$ for $10^{\circ}C$ to $20^{\circ}C$, respectively. In general, the ammonia excretion rate tended to increase with increasing of the water temperature within normal ambient ammonia concentration. However, interestingly, it was observed that ammonia was absorbed rather than excreted above the ambient ammonia concentration of $2.5\;mg\;L^{-1}$, regardless of the water temperature. Thus, the largest ammonia absorption rate (AAR) was obserbed at the level of $98.4\;mg\;TAN\;kg^{-1}\;hr^{-1}$. The relationship ambient ammonia concentration (C) on AAR was following: Y = 1.61 + $10.9X^{0.7}$ ($r^2$ = 0.889).

• Polymer(Korea)
• /
• v.24 no.1
• /
• pp.97-104
• /
• 2000

PAN-based activated carbon fibers/phenolic resin matrix composites (ACFCs) were manufactured via molding process with oxidized carbon fabrics (plain-type) and phenolic resin (resole-type) compounded by 70 : 30 wt%. The green body (as molded) was submitted to carbonization (at 100$0^{\circ}C$) in an inert environment and activation (at 700, 800, 900 and 100$0^{\circ}C$) in a $CO_2$ environment. In this work, the influence of activation temperatures was investigated in surface properties, such as pH, acid- and base-values by titration method, and in adsorption properties, i.e., specific surface area and pore structures by BET-method of the composites. Also, the pressure drops of the specimens were calibrated by ASTM. As a result, the activation temperature influenced the surface property of ACFCs. When the activation temperature was higher than 90$0^{\circ}C$, the surface was gradually developed in basic nature. And, the evolutions of specific surface area, total pore volume and pore size distribution of ACFCs could be easily confirmed the dependence on the activation temperature. Among them, well-developed pore structure from adsorption characteristics was changed of the ACFCs activated at 90$0^{\circ}C$. Also, the pressure drop was slightly decreased with increasing the temperature due to increasing the burn-off with heat treatment temperature of ACFCs.

• Ocean and Polar Research
• /
• v.31 no.3
• /
• pp.231-238
• /
• 2009

A study was carried out to investigate the effect of water temperature on daily pattern and rate of total ammonia nitrogen (TAN) excretion in juvenile dark-banded rockfish Sebastes inermis (mean body weight: $14.8{\pm}0.3g$) under fasting and feeding conditions. Fish were acclimated over 10 days under three different water temperatures (15, 20 and $25^{\circ}C$). After 72 hours of starvation, fasting TAN excretion was measured at each temperature. To investigate post-prandial TAN excretion, fish were hand-fed with a commercial diet containing 47.7% crude protein for 7 days, two times daily at 09:00 and 17:00 hr. Water was sampled from both the inlet and outlet of each chamber every 2 hrs over a 24 hr period. Both fasting and post-prandial TAN excretion increased with increase in water temperature (P<0.05). Mean fasting TAN excretion rates at 15, 20 and $25^{\circ}C$ were 8.1, 9.0 and 9.2 mg TAN kg $fish^{-1}h^{-1}$, respectively. The value of $15^{\circ}C$ was lower than those of 20 and $25^{\circ}C$ (P<0.05), but there was no significant difference between $20^{\circ}C$ and $25^{\circ}C$ (P>0.05). Mean post-prandial TAN excretion rates at 15, 20 and $25^{\circ}C$ were 20.1, 22.9 and 23.4 mg TAN kg $fish^{-1}h^{-1}$, respectively. A peak post-prandial TAN excretion rate occurred after 12 hrs from the first feeding at $15^{\circ}C$ (mean 28.7 mg TAN kg $fish^{-1}h^{-1}$), $20^{\circ}C$ (33.7 mg TAN kg $fish^{-1}h{-1}$) and $25^{\circ}C$ (36.8 mg TAN kg $fish^{-1}h{-1}$), respectively. The TAN loss for ingested nitrogen at $15^{\circ}C$ (36.2%) was lower than that of $20^{\circ}C$ (40.8%) and $25^{\circ}C$ (41.7%). Based on overall results, water temperature exerts a profound influence on the nitrogen metabolism of juvenile dark-banded rockfish.

• Journal of Conservation Science
• /
• v.29 no.3
• /
• pp.261-277
• /
• 2013

This study aims to research the relationship between whitewares and their rare materials from the site of Yanggu and Bunwon through the componential characteristic of the excavated whitewares from the 1st and the 2nd kilns of Chiljeon-ri in Bangsan-myeon, Yanggu-gun. As a result, the sherds were devided according to the chemical compositions of the body and the glaze via their respective production era. However, it considered that the whitewares from Chiljeon-ri had been manufactured with geochemically similar materials and the production process, such as refining and combining materials, had been different. It assumed that the firing temperatures of the whitewares from Chiljeon-ri were around $1,100-1,200^{\circ}C$ and substantially lower than for general whitewares. In the componential analysis, there were disparate properties in the cobalt pigment, which contained trace elements and rare earth elements. A review of the literature revealed a correlation between the whitewares from the late Chosun kiln site in Bunwon-ri and the raw materials from Yanggu-gun, but this was there were various techniques for refining and combining materials in Bunwon-ri.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.31 no.6
• /
• pp.842-851
• /
• 1998

Development and growth of Acartia steueri from Ilkwang Bay, southeastern coast of Korea, were determined under various temperatures and food condition (Isochrysis galbana and Dunaliella salina) in the laboratory. Relationship between egg hatching time ($D_E$, day) and temperature (T, $^{\circ}C$) was $D_E=744(T+3.5)^{-1.97}$. Mean hatching success was $88.4\%$ in temperature range of $8.4\~26.2^{\circ}C$. This suggests that A. steueri may be adapted to the temperature ranges in temperate regions. Post-embryonic development pattern was equiproportional rather than isochronal, with longer stage duration of copepodites than that of the nauplii. Stage duration of NI was the shortest of all developmental stages, while the duration of NII was the longest in duration of the other nauplii. Male was morphologically distinguished from female in CIV stage, and male was developed faster than female. Median development time at a given temperature was calculated from the Belehradek equation by proper multiplication of proportional constant for embryonic development. Body carbon weight at $19.1^{\circ}C$ was increased exponentially with time. Mean specific growth rate of nauplii (0.200 $d^{-1}$), except for NI stage, was not significantly different from that of copepodites (0.190 $d^{-1}$), with the lowest rate in NVI stage (0.107 $d^{-1}$), probably due to energy consumption for metamorphosis rather than somatic growth. The results suggest that although the development pattern determined in this study was not identical with Uye's result for A. steueri (e.g. Uye, 1980b), median development time may be applicable to calculate the stage duration of A. steueri in this study area.

• Asian-Australasian Journal of Animal Sciences
• /
• v.18 no.8
• /
• pp.1188-1193
• /
• 2005

An investigation was carried out to study the effect of two housing systems on physiological responses and energy expenditure of sheep in a semi-arid region of India. Two types of housing management were adopted. First was a shed- $6{\times}3\;m^2$ structure with all the four sides of 1.8 m chain link fencing with a central height of 3 m. The roof was covered with asbestos sheets and with mud floorings. Second was an open corral- $6{\times}3\;m^2$ open space with all the four sides covered with 1.8 m chain link fencing. Thirty-four (32 ewes and 2 rams) sheep of native Malpura breed aged about 18 months (body weight 28 kg ewes; 35 kg rams) were grazed together on a 35 ha plot of native range. All the sheep were grazed as a flock from 08.00 to 17.00 h during a yearlong study. The flock was divided into two groups (16 ewes+1 ram) in the evening and housed as per the systems (Shed and Open Corral). Dry and wet temperatures were recorded at 06.00 h and 21.00 h using a wet and dry bulb-thermometer both inside the shed and in the open corral and temperature humidity index (THI) was calculated. There was significant (p<0.05) difference in the THI between shed and open corral in all the seasons, indicating that shed was always warmer compared to open corral. Rectal temperature (RT) of both the groups of sheep was similar during morning as well as evening throughout the seasons. There were significant (p<0.05) differences in the skin temperature (ST) and respiration rate (RR) between the two groups at both the measurements in all the seasons. Highest energy expenditure (EE) was recorded inside the shed at 21.00 h (224 kJ/h) during monsoon and lowest at 6.00 h during winter (119 kJ/h). There was a significant (p<0.05) difference between the EE inside the shed and that in the open corral. It was concluded that housing had significant effects on the physiological responses and EE of sheep. Provision of housing at night was stressful during monsoon (with less rainfall) and summer, whereas it was protecting the sheep from acute cold during winter in a semi-arid region of India.

• Journal of Mushroom
• /
• v.10 no.4
• /
• pp.160-166
• /
• 2012

The effects of fixed and variable temperatures on fruiting body formation and characters of mushrooms were investigated with normal and thinning treatment plots. In fixed temperature, as temperature was lower, period of harvest was longer as well as days for pinheading in the both of normal and thinning plots. Harvest rate were 91.0, 90.3, and 95.8% at $13^{\circ}C$, $17^{\circ}C$, and $15^{\circ}C$. In the thinning plot, qualities of mushrooms were 7.5, 8.1, and 7.7, and yields were 86.0, 105.9, 104.0g at 13, 15, and $17^{\circ}C$ respectively. In variable temperature with a variable temperature plot, condition II($17^{\circ}C$ for pin-heading(before reverting, 7-8 days)${\rightarrow}16^{\circ}C$ for extending primodia(before thinning, 4-5 days)${\rightarrow}15^{\circ}C$ for extending (after thinning)) was the best for yield which was better than other conditions by 17.4% and 4.0% and quality of mushroom was highest 8.1 among all conditions.

• Ecology and Resilient Infrastructure
• /
• v.2 no.1
• /
• pp.64-79
• /
• 2015

We investigated the tidal current, hydrographic data, and benthic environment of major sea cucumber (Holothuroidea, de Blainville, 1834) habitats in Baengnyeongdo, Jindo and Uljin to understand the optimal environmental or ecological habitat for sea cucumbers. The three study areas were characterized by a cold-water mass of temperatures ranging $12{\sim}18^{\circ}C$, with an active circulation between the surface and deep waters. According to an analysis of the tidal current map, a strong flow velocity of $100{\sim}120cm\;s^{-1}$ appeared in Baengnyeongdo and Jindo. The three sea cucumber habitats showed the common characters of a bottom sediment composed of sand-silt, a diverse seaweed colony and benthic organisms, and boulders and rocks which provide a hideout for the organisms. We aimed to draw the optimal habitat condition for sea cucumbers in Korea, and the result showed that the low water temperature, rapid water flow, active vertical mixing between surface and deep waters, bottom composed by sand-silt, large rocks, and diverse seaweed colony and benthic organism were important factors. The optimal habitat for Juvenile sea cucumbers was the intertidal areas characterized by a muddy bottom, reef, and seaweed. The optimal habitat for adult sea cucumbers was characterized by a place where sand and mud are mixed, and the body size of the sea cucumber was proportional to water depth, and the relatively large boulders and rocks compared to the intertidal area.

• Korean Journal of Ecology and Environment
• /
• v.45 no.2
• /
• pp.190-199
• /
• 2012

The reproductive ecology of an endangered species, Gobiobotia macrocephala (Pisces: Cyprinidae), was investigated in the Seom River, a tributary of the Han River drainage system, from March 2010 to February 2011. During the non-spawning season, no difference in the external morphology was observed between males and females; however, during the spawning season, clear differences merged for the depth and width of the body, preventral length and preanal length in the standard length. The sex ratio of females to males was 1 : 1.01. The spawning season was estimated to last from late April to middle of June, at water temperatures of $15{\sim}25^{\circ}C$. The number of mature eggs in the ovary averaged about $2,134{\pm}930$ (mean${\pm}$SD), and the mean diameter was approximately $0.88{\pm}0.04$ mm. The spawning area was composed of pebble and cobble bottoms (3~10 cm), with current velocities of 13~24 cm $s^{-1}$ and water depths of 12~18 cm. Spawning behavior between males and females was observed in a water tank 14~15 h after injecting females with Ovaprim to promote reproduction. Fish spawned near the water surface with monogamous pairing.

• Journal of fish pathology
• /
• v.9 no.2
• /
• pp.147-155
• /
• 1996

This study was carried out to examine the acute toxic effects of ammonia to the eel, Anguilla japonica in high temperature and pH levels by histopathological observations. The eels of 40 g average body weight were exposed to 4 different concentrations of total ammonia (0, 10, 20, 30 mg/$\ell$) for 24~120 hours. Each concentration was treated under 4 different levels of pH (7.5, 8.0, 8.5, 9.0) and each of these treatments was tested at 2 different temperatures ($27^{\circ}C$, $32^{\circ}C$). Histopathological changes in gill tissues were observed by hematoxylin-eosin stain. As increasing of pH (from 7.5 to 9.0), water temperature (from $27^{\circ}C$ to $32^{\circ}C$), total ammonia concentration (from 0 mg/$\ell$ to 30 mg/$\ell$) and exposure time (from 24 hours to 120 hours), gill discolorated to dark brown with the naked eye and gill tissues showed hypertrophy of gill lamellae, winding of the secondary gill lamellae, epitherial separation and necrosis histopathologically. When gill lamellae epithelium was separated from the blood vessels, gill discolorated to dark brown with the naked eye.