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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korean society of Fisheries Technology
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Journal DOI :
The Korean Society of Fisheries Technology
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Volume & Issues
Volume 20, Issue 2 - Jun 1984
Volume 20, Issue 1 - Mar 1984
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Study on the Behavior of the Fish - 1 . The Swimming Force of Crusian Carp , Carassius Carassius -
Journal of the Korean society of Fisheries Technology , volume 20, issue 1, 1984, Pages 1~5
The author carried out an experiment for the dynamical swimming force of crusian carp, Carassius carassius. The experimental water tank was made of 4mm thick transparent acryl board in the right hexahedral shape (400L
800H mm). The water temperature in the tank ranged 20.6
. The water level in the tank was maintained 70cm high from the bottom. The measurement of the swimming force was carried out by use of strain gauge. The results obtained can be summarized as follows: 1) The momentary maximum swimming force F sub(M) (g) and the sustainable maximum swimming force F sub(s) (g) can be expressed as a function of the body weight W(g). F sub(M) =1.45W, F sub(s) =0.29W where the momentary maximum swimming force means the highest value, and the sustainable maximum swimming force means the mean high value sustained for 4 to 5 seconds presented in the recording paper. 2) F sub(M) and F sub(s) can be expressed as a function of the body length L(cm). F sub(M) =0.11L super(2.63), F sub(s) =0.15L super(1.77) 3) The coefficient of hydraulic resistance for crusian carp was derived as 0.287.
Response of Rock Trout to the Colored Lights
Journal of the Korean society of Fisheries Technology , volume 20, issue 1, 1984, Pages 6~10
The author carried out an experiment to find out the response of rock trout, Hexagrammos otakii (Jordan et starks) to the color lights. The experimental tank (360L
55H cm) was set up in a dark room. Six longitudinal sections with 60cm intervals are marked in the tank to observe the loction of the fish. Water depth in the tank was kept 50cm level. Light bulbs of 20W at the both ends of the tank projected the light horizontally into the tank. Two different colored filters were selected from four colors of red, blue, yellow, and white, and they were placed in front of the light bulbs to make different colors of light. Light intensity were controlled by use of auxiliary filters intercepted between the bulb and the filter. The fishes were acclimatized in the dark for 50 minutes before they were 3employed in the experiment. Upon turning on the light, the number of fish in each section was counted 40 times in 30 second intervals, and the mean of the number of fish in each section was given as the gathering rate of the fish. The colors favourited by the fish was found in the order of white, yellow, red and blue in day time, and red, yellow, blue and white at night time. The gathering rate of fish on illumination period was small and comparatively fluctuated with stability. The difference of the gathering rates on two different colors of light was great.
Measurement of Backscattering Cross Sections of Live Fish
Park, Hae-Hun ; Jang, Ji-Won ;
Journal of the Korean society of Fisheries Technology , volume 20, issue 1, 1984, Pages 11~16
The backscattering cross sections of live fish and the probability density function of fish echoes were measured at side aspect. The measurements were made at 40 and 170 in KHz. The specimen fishes on the experiments were two catfish-total length of 16.8cm(L/λ is about 4.5, where the L is length, the λ is the sound wavelength) and 23cm(L/λ, ~6.1), a carp(Cyprinus carpio) of 17.5cm(L/λ, ~4.7), a Telapia(Tilapia mossambica)of 19.5cm(L/λ, ~5.2) and several fishes. Those lengths ranged from 10.7 to 24.0cm. The results of the measured maximum backscattering cross sections were 5.62
10 super(-5) to 7.23
10 super(-4) m super(2). Huang and clay reported that, when the fish was moving gently, the probaiblity density function of the fish echces was approximately the same with the Rayleigh probability density function. Thereafter Ehrenberg et al. also reported that the Rayleigh probability density function on fish was performed at the critical acoustic length ratio or more in theoretical base. Recently Dahl and Mathisen tested the Rayleigh probability density function on fish when the fish-length-to-wavelength ratios were greater than 100. In this paper the experimental result was also not accorded with the Rayleigh probability density function when the fish-length-to-wavelength rations were lower than the critical ratio
The Optomotor Response of Crusian Carp and Goldfish in Accordance with the Colors of the Wall and the Stripes of the Visual Screen
Journal of the Korean society of Fisheries Technology , volume 20, issue 1, 1984, Pages 17~22
The author carried out an experiment to find on the optomotor response of crusian carp, Carassius carassius and goldfish, Carassius auratus in accordance with the colors of the wall and the stripes labeled on the revolving visual screen. The results are as follows; 1. The optomotor response rate of crusian carp was 80% or more in case of B-Y, R-Bl and W-Bl pair of colors, and 50% or less in case of Bl-B, B-Bl, R-W, R-Y, W-Y and Y-W pair. 2. The optomotor response rate of goldfish was 80% or more in all except B-Bl, W-R and W-Y pair. 3. Mean round number of crusian carp was 7.5-9.5 revolutions in case of W-Bl, Y-Bl, W-B and Y-B pair, and 1.8-3.9 revolutions in case of Bl-B, Bl-Y, B-Bl, B-R, R-All and Y-W pair for 3 minutes. 4. Mean rounded number of goldfish was only 4.1-4.9 revolutions in case of W-Bl, W-B and Y-B pair for 3 minutes.
Effect of Aging Treatment on Fracture Characteristics of High Strength Al-Alloy
Moon, Chang-Kweon ; Oh , Sae-Kyoo ;
Journal of the Korean society of Fisheries Technology , volume 20, issue 1, 1984, Pages 23~29
Nowdays, the high strength aluminum alloys are broadly used for structural purpose, but the practical strengthening method by aging treatment are not much available. So that, in this study, in order to investigate the effect of aging treatment for strengthening on the fracture characteristics of the domestic high strength Al alloy (A2024BE), the variations of the aging temperature and time were taken after solution treatment. By microstructural examination, and by SEM fractographs of the fractures, the effects of aging temperature and time were investigated, considering on the fracture behaviour. The results obtained are as follows: 1) It was confirmed by microstructural investigation that the aging temperature of
and the aging time of 12hours were optimal to get more sound microstructure with distribution of uniform precipitation. 2) By step aging treatment, the proper aging time for obtaining the similar microstructure without any microstructural defects could be shortened in half the normal aging time. 3)By examining the SEM fractographs of the fracture surface, it was found that, regardless of the aging treatment time and temperature, all were intergranular ductile fractures, but the aging treatment at
for 12 hours resulted in dimple-type-transgranular and intergranular-ductile-frature.
A Comparison of the Crack Plane Equilibrium Model for Elastic-Plastic Fracture Analysis with the Irwin's Plastic Zone Corrected LEFM
Lee, Gyu-Yong ; Smith, F.W. ;
Journal of the Korean society of Fisheries Technology , volume 20, issue 1, 1984, Pages 30~36
It is well known that the application of linear elastic fracture mechanics is inadequate to solve the large deformation fracture failures which occurr in ductile manner because of the large scale yielding due to the severe stress concentration in the region adjacent to the crack tip. The authors have been evolved a fracture model, the crack plane equilibrium model, for this kinds of elastic-plastic fracture problems in the previous report. In this report, the crack plane equilibrium model was compared with the Irwin's plastic zone corrected linear elastic fracture mechanics through theoretical comparisons and experimental results to examine the validity of the crack plane equilibrium model as an available tool for nonlinear fracture analysis. Through this study, the main results were reached as follows; Irwin's plastic zone corrected linear elastic fracture mechanics could be applicable only for small scale yielding problems as expected while the crack plane equilibrium model valid as a fracture model for large deformation fracture failure. However, the followings should be considered for the more precise evaluations of CPE model; 1) It is necessary to test more specimens which contain small cracks in the range of 2a/W<0.1. 2) It is important to detect the crack initiation point during the fracture test for determining an accurate fracture load. 3) Effects of specimen thickness in the fracture process zone should be examined.
A Study on the Stability of Uncontinuous Plate Structures with Cracks
Lee, Seon-U ; Kim, Si-Yeong ; Hong, Bong-Gi ;
Journal of the Korean society of Fisheries Technology , volume 20, issue 1, 1984, Pages 37~42
This paper deals with the characterics of the stability of uncontinuous plate structures with cracks. The relation between the J-intergal of the cracks existing in the stress-concentrated regions and local strain are investigated experimentally and theoretically. The BEM(boundary element method)analysis and test results lead to the follow conclusions: 1. A non-dimensional J was computed in a plate stress and strain condition for several kind of loads and crack types. The J design curves are defined as follows: J sub(E)/
sub(y) super(2) a=3.345(e/e sub(y) ) super(2) at e/e sub(y)
1 J sub(E)/
sub(y) super(2) a=3.345(e/e sub(y) ) at e/e sub(y)
1 2. Use of this curve provides a good estimation for the uncontinuous plate structures with cracks existing in the stress and strain concentrated region. 3. The stability of the characteristics is mainly depenent upon not the length of cracks but the type of the cracks.
A Study on the Vibration Analysis of Beam
Kim, Yeong-Sik ; Moon, Duk-Hong ;
Journal of the Korean society of Fisheries Technology , volume 20, issue 1, 1984, Pages 43~48
The transfer matrix method is well-known and extensively used for finding solutions in vibration problems. At the final stage of this method natural frequencies are obtained by a trial and error search procedure. In this paper authors presented the method which needed only a few division number to yield an accurate solution and the most effective method to get an approximate solution in the case of beam vibrations. The methods which were presented by authors could be applied for the beam with nonuniform section and uniformly distributed load, and the values of numerical calculations by these methods have just agreed with those of experiments.
Optimization for Underwater Welding of Marine Steel Plates
Journal of the Korean society of Fisheries Technology , volume 20, issue 1, 1984, Pages 49~59
Optimizing investigation of characteristics of underwater welding by a gravity type arc welding process was experimentally carried out by using six types of domestic coated welding electrodes for welding of domestic marine structural steel plates (KR Grade A-1, SWS41A, SWS41B,) in order to develop the underwater welding techniques in practical use. Main results obtained are summarized as follows: 1. The absorption speed of the coating of domestic coated lime titania type welding-electrode became constant at about 60 minutes in water and it was about 0.18%/min during initial 8 minutes of absorption time. 2. Thus, the immediate welding electrode could be used in underwater welding for such a short time in comparison with the joint strength of in-atmosphere-and on-water-welding by dry-, wet-or immediate-welding-electrode. 3. By bead appearance and X-ray inspection, ilmenite, limetitania and high titanium oxide types of electrodes were found better for underwater-welding of 10 mm KR Grade A-1 steel plates, while proper welding angle, current and electrode diameter were 6
, above 160A and 4mm respectively under 28cm/min of welding speed. 4. The weld metal tensile strength or proof stress of underwater-welded-joints has a quadratic relationship with the heat input, and the optimal heat input zone is about 13 to 15KJ/cm for 10mm SWS41A steel plates, resulting from consideration upon both joint efficiency of above-100% and recovery of impact strength and strain. Meanwhile, the optimal heat input zone resulting from tension-tension fatigue limit above the base metal's of SWS41A plates is 16 to 19KJ/cm. Reliability of all the empirical equations reveals 95% confidence level. 6. The microstructure of the underwater welds of SES41A welded in such a zone has no weld defects such as hydrogen brittleness with supreme high hardness, since the HAZ-bond boundary area adjacent to both surface and base metal has only Hv400 max with the microstructure of fine martensite, bainite, pearlite and small amount of ferrite.
On Calculation of Bending Frequency of a Beam with a Crack
Journal of the Korean society of Fisheries Technology , volume 20, issue 1, 1984, Pages 60~64
To calculate the bending frequency of a beam with a crack, the author has developed the computor programe. With a simple example, numerical calculations and experiments were carried out. The results were as follows. 1) As the values of experiments have comparatively agreed with those of calculations, it was proved that the computor program could he applied to a beam with a crack. 2) In the case that the shape of crack is narrow and deep at the fixed edges, the value of experiment may not considerably correspond with that of calculation. 3) If the bending frequency was varied a few % due to a crack, it was turned out that the beam might be fatal on strength.