• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.24 no.3
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• pp.97-106
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• 2018

This study aimed at examining the suitability of $Tenax^{(R)}$ for the migration testing of food packaging materials, which is currently approved in the EU as a dry food simulant. The results are used as a basis to examine the feasibility of introducing $Tenax^{(R)}$ to Korean regulation. The OMVs of test specimen into various solvents (diethyl ether, ethanol, pentane, and acetone) after exposure to $100^{\circ}C$ for 1 hr were compared. Diethyl ether showed the highest OMV ($1.33mg/dm^2$) among the solvents tested. When the tests were conducted with different amounts of $Tenax^{(R)}$ of 2, 4, or 8 g per specimen, the OMVs were 0.75, 1.33 and $1.40mg/dm^2$, respectively. The OMV obtained with a closed system after wrapping with aluminum foil showed a significantly higher OMV ($1.61mg/dm^2$) than that without aluminum wrapping ($1.318mg/dm^2w$) and an open system without lid ($1.06mg/dm^2$). The specific migration rates of surrogates spiked in the polyethylene test film and paper samples into $Tenax^{(R)}$ were compared with those into liquid food simulants including 95% ethanol and n-heptane, and actual foods such as starch, skim milk, and sugar. In general, the specific migration levels of surrogates into $Tenax^{(R)}$ were similar compared with n-heptane, however those were significantly higher than into actual foods. These results suggest that $Tenax^{(R)}$ may be used as a food simulant for the long-term preservation of dried foods and paper products. However, more studies need to be conducted to investigate the factors influencing the migration into $Tenax^{(R)}$, such as the types of foods and packaging materials tested, migration conditions, and surrogates properties etc.

• Journal of Practical Agriculture & Fisheries Research
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• v.23 no.2
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• pp.43-50
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• 2021

Growth tests on the Yuldo, Supum1 and Supum2 cultivars of Pyropia dentata were performed at the Eoran and Imha aquafarm, Haenam in Jeollanamdo, from October to December in 2017. The mean water temperature ranged from 5.4 to 26.4 ℃. In Eoran aquafarm (flating raft method), dissolved total nitrogen (DTN), dissolved total phosphorus (DTP), total nitrogen (TN), total phosphorus (TP) and chemical oxygen demand (COD) ranged from 0.091 to 0.181 mg/L, 0.007 to 0.019 mg/L, 0.114 to 0.187 mg/L, 0.008 to 0.033 mg/L and 0.200 to1.000 mg/L, respectively. In Imha aquafarm (fixed pold method), DTN, DTP, TN, TP and COD ranged from 0.118 to 0.276 mg/L, 0.005 to 0.024 mg/L, 0.155 to 0.305 mg/L, 0.009 to 0.042 mg/L and 0.300 to1.400 mg/L, respectively. In order to investigate the number of conchospores attached on the Pyropia net, which was cut into about 4cm long. The mean number of conchospores of Yuldo, Supum1 and Supum2 cultivars were 39.5, 26.5, 72.5, respectively. Young thalli were harvested two times at Eoran aquafarm, and three times at Imha aquafarm. In eoran aquafarm, the mean thallus length of Yuldo, Supum1 and Supum2 cultivars were 49.9, 46.0, 42.0 cm on October and 163, 126.0, 263.0 cm on November, respectively. The mean thallus width of Yuldo, Supum1 and Supum2 cultivars were 5.8, 4.6, 11.5 cm on October and 20.9, 11.5, 14.0 cm on November, respectively. In Imha aquafarm, the mean thallus length of Yuldo, Supum1 and Supum2 cultivars were 119.0, 60.9, 71.0 cm on October, 196.0, 132.0, 262.0 cm on November and 187.0, 281.0, 296.0 cm on December, respectively. The mean thallus width of Yuldo, Supum1 and Supum2 cultivars were 4.2, 3.4, 3.1 cm on October, 8.9, 6.2, 6.6 cm on November and 11.7, 11.6, 9.4 cm on December, respectively. In eoran aquafarm, contents of moisture, crude ash, crude lipid, crude protein and carbohydrate of three cultivars ranged from 11.64 to 20.15, 19.54 to 21.19, 0.00 to 0.18, 29.78 to 37.81, 29.16 to 29.71, respectively. In Imha aquafarm, contents of moisture, crude ash, crude lipid, crude protein and carbohydrate of three cultivars ranged from 8.43 to 9.15, 11.42 to 17.49, 0.00 to 0.00, 31.90 to 37.54, 36.30 to 42.24, respectively.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.29 no.1
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• pp.76-83
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• 1984

This experiment was performed to investigate the flowering habit of sesame (Sesamum indicum L.). Sesame varieties tested could be classified into 8 different plant types by their morphological traits such as capsule shape, capsule setting habit and branching types among sesame gene pool of Crop Experiment Station, ORD. The first flower was appeared at the lowest node on main stem. Flowers were appeared progressively toward the tip of the main stem and also toward the tips of branches. The interval of flowering for a node was about one day, but 3 to 8 days for the flowers on the tips. Side flowers started at 4 to 5 nodes lower than those of center flower at the same day. Flowers were beared 2 by 1 node on the middle part of flower setting node (7-9) in mono capsule setting habit in spite of its normal is 1 by 1 node on the other nodes. Flowers were beared opposite direction on each node of stem and flowering toward the tip of main stem composed of cross shape between nodes and spiral, reverse of clockwise direction. We called this habit as cross spiral flowering order and cross spiral phyllotaxis. The first flower on branches was appeared when center flower on the 5th node of main stem began to flower. The branches produced at higher nodes on main stem showed larger flowering periods and more number of flowers than that at lower parts. BTB (Branch, Tricapsule, Bicarpels, 4 Loculi) type showed three capsule setting habits and same flowering period both on main stem and branches while BTQ (Branch, Tricapsule, Quadricarpels, 8 Loculi) type showed three capsule setting habit on main stem and mono-capsule setting habit on branches. In BTQ type, the period of flowering was much shorter on branches than on main stem. Branching type was considered more promising than non branching type for the breeding of early maturing high yielding variety because branching type has the advantage of bearing a lot of flowers in comparatively short flowering period.

• Journal of Practical Agriculture & Fisheries Research
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• v.16 no.1
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• pp.93-103
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• 2014

This experiment was conducted to investigate the effects of different fat source feeding on growth performance, visceral organ weight, meat color, excreta microflora and blood profiles in broilers. A total of 768 1-d-old ROSS 308 broilers (mixed gender) with an initial average body weight of 39.68 ± 0.14 g were randomly allotted to 4 treatments with 12 replicate pens per treatment and 16 broilers per pen for 32 days. Dietary treatments were: 1) SBO, basal diet + 5% soybean oil, 2) PF, basal diet + 5% poultry fat, 3) TAL, basal diet + 5% tallow, and 4) LARD, basal diet + 5% lard. During d 1 to 14, broilers fed TAL diet had a higher (P<0.05) body weight gain (BWG) than broilers fed with PF and LARD diets, moreover, broilers fed TAL diet had a higher (P<0.05) feed intake than broilers fed SBO, PF and LARD diets. Overall (d 0-32), BWG in SBO and TAL treatments was greater (P<0.05) than that in LARD treatment. The meat color a^* (redness) of broilers fed with LARD diet was increased (P<0.05) compared with broilers fed with PF and TAL diets. No difference was observed in visceral organ weight of liver, spleen, bursa of Fabricius, breast muscle, abdominal fat, gizzard and excreta concentrations of Lactobacillus and Escherichia coli. The blood LDL cholesterol concentration in TAL treatment was higher (P<0.05) than that in LARD treatment. In conclusion, broilers supplementation with tallow could improve not only the body weight gain and feed intake but also blood LDL cholesterol concentration. Moreover, broiler fed lard could increase a^* (radness) of meat color, while the soybean oil supplementation improve body weight gain in broilers.

• Journal of Practical Agriculture & Fisheries Research
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• v.17 no.1
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• pp.57-71
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• 2015

This study was conducted to develop the fertigation system with a peristaltic hose pump and brushless DC motor. The fertigation system was consisted of sensor, main controller, motor control unit, peristaltic pump, water supply pump, control panel, and filter. The peristaltic pump discharges liquid by squeezing the tube with rollers. Rollers attached to the external circumference of the rotor compresses the flexible tube. The fluid is contained within a flexible tube fitted inside a circular pump casing. The developed fertigation system has no mixing tank but instead injects directly a concentrated nutrient solution into a water supply pipe. The revolution speed of the peristaltic pump is controlled by PWM (Pulse width modulation) method. When the revolution speed of the peristaltic pump was 300rpm, the flow rate of the 3.2, 4.8, 6.3mm diameter tube was 202, 530, 857mL/min, respectively. As increasing revolution speed, the flow rate of the peristaltic pump linearly increased. As the inner diameter of a tube larger, a slope of graph is more steep. Flow rate of three roller was more than that of four roller. Flow rate of a norprene tube with good restoring force was more than that of a pharmed tube. As EC sensor probe was installed in direct piping in comparison with bypass piping showed good performance. After starting the system, it took 16~17 seconds to stabilize EC. The maximum value of EC was 1.44~1.7dS/m at a setting value of 1.4dS/m. The developed fertigation system showed ±0.06dS/m deviation from the setting value of EC. In field test, Cucumber plants generally showed good growth. From these findings, this fertigation system can be appropriately suitable for fertigation culture for crops.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.38 no.4
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• pp.350-359
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• 1993

The effect of gibberellic acid ($GA_3) and abscisic acid (ABA) on KCl-enhanced proteolysis of senescing leaves of rice(Oryza sativa L. cv. Chilsung) was studied. Emphasis was given to their effects on KCI-enhanced efflux of amino acids and proteinase activity. When treated singly, $GA_3 affected leaf proteolysis little, while ABA increased proteolysis, the rate of amino acid efflux, and ribulose -1,5 -bisphosphate carboxylase / oxygenase (Rubisco)-degrading endoproteinase activity. An additive increase in all three parameters mentioned above was observed when leaves were treated with ABA and KCl. No such an additive effect was found when $GA_3 was treated with KCl. Both $GA_3 and ABA helped to alleviate the KCI-suppressed activity of Rubisco-degrading exoproteinases. The additive increase in proteolysis of rice leaves in the presence of both ABA and KCl could thus be ascribed to a further increase in the efflux of protein hydrolyzates and Rubisco-degrading endoproteinase activity. An increase in proteolysis was accompanied by a decrease in water absorption, and the combined treatment of ABA with KCl resulted in a further reduction of water absorption.

• Journal of the Korean Geotechnical Society
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• v.24 no.4
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• pp.101-114
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• 2008

Pressurized grouting is a common technique in geotechnical engineering applications to increase the stiffness and strength of the ground mass and to fill boreholes or void space in a tunnel lining and so on. Recently, the pressurized grouting has been applied to a soil-nailing system which is widely used to improve slope stability. Because interaction between pressurized grouting paste and adjacent ground mass is complicated and difficult to analyze, the soil-nailing design has been empirically performed in most geotechnical applications. The purpose of this study is to analyze the ground behavior induced by pressurized grouting paste with the aid of laboratory model tests. The laboratory tests are carried out for four kinds of granitic residual soils. When injecting pressure is applied to grout, the pressure measured in the adjacent ground initially increases for a while, which behaves in the way of the membrane model. With the lapse of time, the pressure in the adjacent ground decreases down to a value of residual stress because a portion of water in the grouting paste seeps into the adjacent ground. The seepage can be indicated by the fact that the ratio of water/cement in the grouting paste has decreased from a initial value of 50% to around 30% during the test. The reduction of the W/C ratio should cause to harden the grouting paste and increase the stiffness of it, which restricts the rebound of out-moved ground into the original position, and thus increase the in-situ stress by approximately 20% of the injecting pressures. The measured radial deformation of the ground under pressure is in good agreement with the expansion of a cylindrical cavity estimated by the cavity expansion theory. In-situ test revealed that the pullout resistance of a soil nailing with pressurized grouting is about 36% larger than that with regular grouting, caused by grout radius increase, residual stress effect, and/or roughness increase.

• Journal of Practical Agriculture & Fisheries Research
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• v.18 no.1
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• pp.13-24
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• 2016

Sixty Hanwoo steers(15 months of age; 409±29.2 kg of BW) were used to evaluate the effects of dietary vitamins A and D restriction on carcass characteristics. Steers were allotted randomly to 1 of 4 treatments: Control(diet supplemented with vitamins A, D and E), -A (diet supplemented with vitamins D and E), -D(diet supplemented with vitamins A and E) and -AD(diet supplemented with vitamin E only). Steers were fed the experimental diet for a period of 8 months(until 23 months of age), and then supplemented with vitamins A and D at 0.05% of the diet(as fed-basis) from 24 to 26 months of age, and at 0.1% of the diet from 27 to 31 months of age(harvesting time). Dietary restriction of vitamins A and D did not affect DM intake, daily gain and feed conversion ratio. But the concentration of serum retinol was significantly(P<0.05) decreased by vitamin A restriction with the lowest concentration being seen at 23 months of age(345.0 ㎍/L and 326.7㎍/L for control and -D treatment versus 169.3 ㎍/L and 175.4 ㎍/L for -A and -AD treatments). The serum concentration of 25(OH)D₃ was also decreased significantly(P<0.05) by vitamin D restriction and the lowest concentration was seen at 18 months of age(53.7ng/ml and 61.8ng/ml for control and - A treatment versus 24.0 ng/ml and 24.5 ng/ml for -D and -AD treatments). After the restriction period of vitamins A and D, the concentrations of retinol and 25(OH)D₃ for - A, -D and -AD treatments were recovered at those of control. Dietary restriction of vitamins A and D did not affect carcass weight, backfat thickness, ribeye area, quality grade and yield grade. But marbling score was significantly increased by vitamin A restriction compared with control(6.73, 6.87 and 5.73 for -A, -AD and control, respectively). The results of the present study suggested that dietary vitamin A restriction could improve marbling score in Hanwoo steers.

• Journal of Practical Agriculture & Fisheries Research
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• v.21 no.1
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• pp.29-40
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• 2019

In Korea kiwifruit growing area is limited to southern coastal region and Jeju island, partly due to the lack of information on their cold hardiness in winter. This study was carried out to investigate cold hardiness of Korean kiwifruit cultivars in a period of dormancy for using it as preliminary data to expand the cultivation area of kiwifruit in Korea. A total of five kiwifruit cultivars in two species and hybrid, Actinidia deliciosa ('Hayward' and 'Garmrok'), A. chinensis ('Goldone') and A. arguta hybrid ('Bangwoori' and 'Skinny Green') were subjected to five freezing treatments of -12℃, -15℃, -18℃, -21℃ and -24℃. Cell membrane damage in all cultivars initiated in -18℃/32h and cell membrane stability was lost in -24℃ in most cultivars, except for 'Skinny Green'. Cold hardiness was estimated by 50% lethal temperature (LT₅₀) which was determined by triphenyl tetrazolium chloride (TTC) reduction. In branches, LT₅₀ was -15℃ in 'Hayward' and 'Garmrok', -18℃ in 'Bangwoori' and -21℃ in 'Goldone.' The LT₅₀ of buds on 'Hayward' and 'Garmrok' was 56 and 42 hours in -15℃ and 4 and 11 hours in -18℃, respectively; however, LT₅₀ of buds on 'Goldone' was 51 hours in -18℃ and that on 'Bangwoori' was 3 hours in -24℃. Cold hardiness results imply that it may be difficult for cultivars in A. deliciosa such as 'Hayward' and 'Garmrok' to be grown in the north of southern coastal region in Korea; however, it can be possible for several cultivars in A. chinensis and A. arguta hybrid to be grown in the northern part of Korean kiwifruit belt if cold tolerance in the thaw is confirmed.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.3
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• pp.344-352
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• 2012

Soil physical properties determine soil quality in aspect of root growth, infiltration, water and nutrient holding capacity. Although the monitoring of soil physical properties is important for sustainable agricultural production, there were few studies. This study was conducted to investigate the condition of soil physical properties of arable land according to land use across the country. The work was investigated on plastic film house soils, upland soils, orchard soils, and paddy soils from 2008 to 2011, including depth of topsoil, bulk density, hardness, soil texture, and organic matter. The average physical properties were following; In plastic film house soils, the depth of topsoil was 16.2 cm. For the topsoils, hardness was 9.0 mm, bulk density was 1.09 Mg $m^{-3}$, and organic matter content was 29.0 g $kg^{-1}$. For the subsoils, hardness was 19.8 mm, bulk density was 1.32 Mg $m^{-3}$, and organic matter content was 29.5 g $kg^{-1}$; In upland soils, depth of topsoil was 13.3 cm. For the topsoils, hardness was 11.3 mm, bulk density was 1.33 Mg $m^{-3}$, and organic matter content was 20.6 g $kg^{-1}$. For the subsoils, hardness was 18.8 mm, bulk density was 1.52 Mg $m^{-3}$, and organic matter content was 13.0 g $kg^{-1}$. Classified by the types of crop, soil physical properties were high value in a group of deep-rooted vegetables and a group of short-rooted vegetables soil, but low value in a group of leafy vegetables soil; In orchard soils, the depth of topsoil was 15.4 cm. For the topsoils, hardness was 16.1 mm, bulk density was 1.25 Mg $m^{-3}$, and organic matter content was 28.5 g $kg^{-1}$. For the subsoils, hardness was 19.8 mm, bulk density was 1.41 Mg $m^{-3}$, and organic matter content was 15.9 g $kg^{-1}$; In paddy soils, the depth of topsoil was 17.5 cm. For the topsoils, hardness was 15.3 mm, bulk density was 1.22 Mg $m^{-3}$, and organic matter content was 23.5 g $kg^{-1}$. For the subsoils, hardness was 20.3 mm, bulk density was 1.47 Mg $m^{-3}$, and organic matter content was 17.5 g $kg^{-1}$. The average of bulk density was plastic film house soils < paddy soils < orchard soils < upland soils in order, according to land use. The bulk density value of topsoils is mainly distributed in 1.0~1.25 Mg $m^{-3}$. The bulk density value of subsoils is mostly distributed in more than 1.50, 1.35~1.50, and 1.0~1.50 Mg $m^{-3}$ for upland and paddy soils, orchard soils, and plastic film house soils, respectively. Classified by soil textural family, there was lower bulk density in clayey soil, and higher bulk density in fine silty and sandy soil. Soil physical properties and distribution of topography were different classified by the types of land use and growing crops. Therefore, we need to consider the types of land use and crop for appropriate soil management.