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A Study on the Ship`s Collision Avoiding Action Analyzed from a Viewpoint of Ship Kinematics (선체운동학적으로 본 충돌회피동작에 관한 연구)

  • 김기윤
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.14 no.2
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    • pp.97-112
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    • 1978
  • The rule 15, 16 and 17 of International Regulations for Preventing collisions at Sea direct actions to avoid collision when two power-driven vessels are crossing. But these rules do not present the safety minimum approaching distances outside which a give- way vessel deeps out of the way of a stand-on vessel. In this paper, the author analyzed the ship's collision avoiding actions from a viewpoint of ship kinematics as the method to calculate this distance. The author worked out mathematic formulas for calculating the safety minimum approaching distances outside which the give-way vessel takes the actions to avoid collisions in accordance with the cross angles of the crossing vessels' courses. Figuring out actually the values of maneuvering indices of the M. S. Koan Ack San (GT: 224tons), the training ship of the National Fisheries University of Busan and the M. S. Golden Clover (GT: 101, 235tons) of the Eastern Shipping Co., Ltd. through their Z test, the author applied these values to the calculating formulas and calculated the safety minimum approaching distances. The results of calculations are as follows; 1. The greatest distance is to be kept by the give-way vessel to avoid collision when the cross angle of courses is 90$^{\circ}$ or near it. In such case the safety minimum approaching distance of a small vessel must be more than 5 times of her own length and that of a large vessel more than 11 times of her own length. 2. Collision danger is greater when crossing angle is obtuse than in an acute angle, therefore greater distance is to be kept by the give-way vessel to avoid collision in the case of the obtuse angle. 3. The actions to be taken to avoid collisions by the give-way vessel in Rule 16 and by the stand-on vessel in Rule 17(a)(ii) of International Regulations for Preventing Collisions at Sea, must be done outside the above safety minimum approaching distance. When inevitably such actions are to be taken within the safety minimum approaching distance, they should be accompanied with engine motions.

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A Case Study on the Effective Liquid Manure Treatment System in Pig Farms (양돈농가의 돈분뇨 액비화 처리 우수사례 실태조사)

  • Kim, Soo-Ryang;Jeon, Sang-Joon;Hong, In-Gi;Kim, Dong-Kyun;Lee, Myung-Gyu
    • Journal of Animal Environmental Science
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    • v.18 no.2
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    • pp.99-110
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    • 2012
  • The purpose of the study is to collect basis data for to establish standard administrative processes of liquid fertilizer treatment. From this survey we could make out the key point of each step through a case of effective liquid manure treatment system in pig house. It is divided into six step; 1. piggery slurry management step, 2. Solid-liquid separation step, 3. liquid fertilizer treatment (aeration) step, 4. liquid fertilizer treatment (microorganism, recirculation and internal return) step, 5. liquid fertilizer treatment (completion) step, 6. land application step. From now on, standardization process of liquid manure treatment technologies need to be develop based on the six steps process.

Feed Intake and Digestibility in Korean Native Goats Fed Fermented Domestic Agricultural By-Products (국내산 농산부산물 발효사료를 급여한 재래산양의 사료섭취량 및 소화율)

  • 안종호;유황종;김현진;조익환;이주삼
    • Korean Journal of Organic Agriculture
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    • v.8 no.3
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    • pp.111-120
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    • 2000
  • In this study, by-products of rice bran, rice hull, bean curd dregs and food waste were fermented with different ratios of 26, 26, 34 and 14% respectively and the experimental diets were prepared mixing it with various ratios of commercial diets (fermented feed commercial feed : A 80 : 20, B 70 : 30, C 60 : 40, D 50:50). In Experiment I, feed intake, nutrients digestibilities and nitrogen retention were investigated and body weight gain in Experiment 1. For chemical composition of experimental diets, crude protein contents were 13.73, 13.78, 14.45 and 15.14% in A, B, C and D respectively and the contents of crude fat and crude fiber were highest in A as 8.66 and 27.82% respectively. 2. Dry hurler intakes were significantly higher (P<0.05) in A(362.06g/d) and C(358.49g/d) than B and D. Intakes of crude protein and crude fat were not significantly different (P>0.05) among treatments however those of crude fiber and crude ash were significantly higher (P>0.05) in A(101.47g/d). 3. Dry matter digestibilities in the range of 53.38∼68.81% in all treatments have shown the highest value in C of 60% fermented feed plus 40% commercial diet but the lowest in A of 80% of fermented feed plus 20% commercial diet (P<0.05). 59.85% of digestibility of crude protein in A was also lowest among all treatments (p<0.05), 4. 8.47g/d of nitrogen intake in C was recorded highest (P<0.05) however the highest nitrogen retention was marked in B of 50% fermented feed plus 50% of commercial diet due mainly to lower excretion of nitrogen through feces. 5. The data of live weight gain in Experiment II has not been shown as a result since the proper daily gain of body weight was achieved only in D as 88.89g/d and the goats in other treatments have shown frequent diarrhea. However, neglecting the animals with diarrhea, higher amounts of concentrates in the diets (C and D) showed the tendency of higher weight gain. 6. In this study, feeding 60% fermented feed manufactured with domestic agricultural by-products of rice bran, rice hull, bean curd dregs and food waste to Korean native goats have shown satisfactory results of intake and digestibility and it indicates that utilization of domestic agricultural by-products in goats could be improved by the process of fermentation. However it's effects on body weight gain and nitrogen retention were below than expected. Different sources of feedstuff for fermentation may result in different performances of animals. However, to draw overall conclusion from this study, 50∼60% of fermented feed can be recommended in the case of mixing with concentrates.

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Comparison on the Behavior according to Shapes of Tension Web member in gap K-joints in Cold-formed Square Hollow Sections (인장웨브재 형태에 따른 각형강관 갭K형 접합부의 거동 비교)

  • Jeong, Sang Min;Bae, Kyu Woong;Moon, Tae Sup
    • Journal of Korean Society of Steel Construction
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    • v.17 no.5 s.78
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    • pp.561-568
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    • 2005
  • The object of this paper is to determine appropriateness for use of high-strength tensile bar as a tension web member. The gap K-joint of tensile bar types were compared with gap K-joint of square hollow section (SHS) types. For the same width-to-thickness ratio ($2{\gamma}=33.3$ ), tests were performed on four specimens of the SHS type and eight specimens of the tensile bar type. The comparison of capacity with the experimental results showed a capacity of the SHS type joint to be higher than that of the tensile bartype joint for the same brace-to-chord width ratio. Moreover, the capacity of the SHS type joints increased proportionally to the width ratio ${\beta}$), while tensile bar type joints increased as the tension width ratio (${\beta}2$). In failure mode, SHS-type specimens showed local buckling of the compression brace and plastic failure was observed between the tension brace and chord face, and with the tensile bar type specimens there appeared punching shear failure of the chord face at the toe of the connection plate. It is, therefore, concluded that width-to-thickness ratio should be lower than that of the hollow-section type and the relation between tension and compression width ratio should be considered.

Evaluation of In-plane Buckling and Ultimate Strength for Braced Arch Ribs (브레이스트 아치 리브의 면내 좌굴 및 극한강도 평가)

  • Park, Yong Myung;Heo, Taek Young;Lee, Pil Goo;Noh, Kyeung Bae
    • Journal of Korean Society of Steel Construction
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    • v.16 no.6 s.73
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    • pp.759-768
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    • 2004
  • The parametric analysis of vertically braced steel pipe arch ribs was performed to evaluate their in-plane buckling strengths and ultimate load-carrying capacities. The elastic and plastic behavior of braced arch ribs, unlike those of the usual single arch ribs, are affected by such factors as the flexural rigidity of the brace member, brace and pipe ribs spacing, loading situation, and arch curvature. To analyze these effects, several parameters were included, such as the rise-to-span ratio, the second moment of the inertia ratio of the rib to the brace member, the space ratio of the brace, the space ratio of the upper and lower ribs, the initial crookedness, the slenderness ratios of the braced arch ribs, and the loading conditions were considered with live-load-to-dead-load ratios. Based on the results of the parametric analyses, a proper profile of the braced arch rib was proposed. A large-scale structural experiment was also performed to evaluate the ultimate strength of the braced arch rib. The test results were determined to reasonably coincide with the analytical ones.

Effect of Feed Value and Fermentative Quality According to Harvesting Time of Barley and Wheat Grain Silage (수확시기에 따른 맥류 곡실발효사료의 사료가치 및 발효품질)

  • Song, Tae-Hwa;Oh, Young-Jin;Kang, Hyeon-Jong;Park, Tae-Il;Cheong, Young-Keun;Kim, Yang Kil;Kim, Bo-Kyeong
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.60 no.2
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    • pp.174-179
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    • 2015
  • This experiment was conducted to determine the optimal harvesting time for barley and wheat grain for the production of fermented grain feeds, and to investigate their fermentation quality according to harvesting time. As a result, grain moisture content was decreased with late harvest, whereas spike weight ratio and 1000 grain weight were increased with prolonged period after heading. Grain yielding was increased with late harvesting time significantly at p<0.05. Crude protein content was increased with late harvesting time, but crude fiber content was decreased. Crude fat and ash content were slightly decreased, but not statistically significant. Comparing the effects of fermentation on feed value of winter cereal grain, the approximate compositions were slightly increased after fermentation, but the difference was not significant. Fermentations resulted in increasing the pH value of winter cereal grain silage with late harvesting time, but decreasing the lactic acid content (p<0.05). No significant difference was found in acetic acid, and butyric acid was not detected. Considering the quantity and quality of fermentation, barley and wheat can be used for winter cereal grain silage when they were harvested at 35 days and 40-45 days after heading, respectively.

Reduction of Salt Concentration in Food Waste by Salt Reduction Process with a Rotary Reactor (로터리식 저염화 공정설비에 의한 음식물 쓰레기의 염분농도 저감)

  • Kim, Wi-sung;Seo, Young-Hwa
    • Journal of the Korea Organic Resources Recycling Association
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    • v.13 no.1
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    • pp.61-70
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    • 2005
  • In order to reduce salt(as NaCl) contents in food waste and to improve the quality of discharged wastewater produced during the recycling process of food waste for the purpose of compost and feed stuff, a salt reduction process by added water into food waste was developed. The pilot plant with a rotary type salt reduction equipment to manage continuously 0.5 ton food waste per hour was constructed and the efficiency was tested. The amount of added water was calculated by the water content and the efficiency of dewatering process of food waste. Approximately 0.8 liter water per a kilogram of food waste was injected into the reactor in which food waste was pouring simultaneously, then diluted/mixed in a rotary reactor. About 1.1 liter of leachate including added water was generated, but the leachate contained a very high content of organic particles, so most particles were recovered by two step solid-liquid separation process. The first step was a gravitational filtering process using screens with a pore diameter of 1mm, and the second separation process was centrifugal process. Organic quality of food waste which had been desalted was maintained by inputting the entirely recovered organic particles. The efficiency of salt reduction of food waste was estimated by measuring a chloride anion by titration and salinity by a probe. The results by the two different measuring methods were always over 50%, and the quality of final wastewater was improved up to $200mg/{\ell}$ as TS(total solid) by an additional settling process after the two step solid-liquid separation process.

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Effects of Media and Plant Growth Regulators on Germination of Somatic Embryos of Aralia elata Seem (두릅나무 체세포배(體細胞胚)의 발아(發芽)에 미치는 배지(培地) 및 식물생장조절제(植物生長調節劑)의 영향(影響))

  • Park, Cheol-Ho;Lee, Youn-Su;Jhang, Han-Ho;Kim, Nam-Soo;Shin, Young-Boum
    • Korean Journal of Medicinal Crop Science
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    • v.2 no.3
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    • pp.241-245
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    • 1994
  • Effects of media and plant growth regulators on the germination of somatic embryos of Angelica tree(Aralia elata Seem.) was studied for the mass production of Angelica tree through tissue culture. MS medium was found to be the most effective for the germination of somatic embryos(65% germination rate), Among the MS medium, the medium containing 25% less inorganic salts and 1% less sucrose was found to be the most effective. Gelling agent with 0.2-0.3% gelrite promoted the germination of somatic embryo$(65{\sim}70%)$ and caused good growth of shoots and roots. 0.1 mg/l of BA and kinetin treatment caused $65{\sim}70%$ germination rate of somatic embryos and good growth of shoots and roots, and resulted in high percentage of dry matter. 1mg/l or 5 mg/l treatment of putrescine, and 10 mg/l treatment of spermidine caused 90% germination rate of somatic embryos and good growth of plant organs, and inhibited vitrification of regenerated plants.

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A Study on the New Type Rib of Steel Deck Plates (새로운 형태의 강바닥판 리브에 대한 연구)

  • Chu, Seok Beom;Park, Jong Hae
    • Journal of Korean Society of Steel Construction
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    • v.26 no.6
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    • pp.605-615
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    • 2014
  • The purpose of this study is to propose an economic new type rib by applying plate stiffening methods of the corrugated plate and the honey-comb sandwich panel to the steel deck plate and comparing the new type rib with existing open and closed ribs. The trapezoidal corrugated type, ㄹ type, honey-comb type and ㅁ type ribs are considered as new type ribs and the moment and the steel volume are compared with that of open ribs and closed ribs. The results shows that the honey-comb type and ㅁ type ribs are good in aspects of economic feasibility and the ㅁ type is better than the honey-comb type. To make the ㅁ type rib applicable to the steel deck plate, the sensitivity analysis and parametric study are performed and the system to select the proper section under the particular stress condition is established. The closed rib of real bridges is compared with the ㅁ type rib of the proposed system and it is known that the new type rib is more economic. Therefore, more economic steel deck plates can be achieved by using the system proposed in this study for the plate stiffened with the new ㅁ type rib.

Culture Studies on te Green Alga, Caulerpa okannurae I. Growth and Regenetation (녹조류, 옥덩굴(Caulerpa okamurae)의 양식을 위한 연구 I . 생장과 재생)

  • 최창근;황은경;손철현
    • Journal of Aquaculture
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    • v.13 no.3
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    • pp.253-258
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    • 2000
  • Monthly samplings were made at Yongho-dong, Pusan, on the south eastern coast of Korea from May 1998 to April 1999 to investigate population growth and regeneration pattern of C. okanurae. The growth of erect branches was dependent mainly on the habitat water temperature. Maximum length of an erect branch was 13.4 cm in July and the minimum was 5.1 cm in March; during the corresponding months maximum and minimum weights of the alga were 2.2 and 0.7 g, respectively. During this investigation, gametangia did not occur. Regeneration of excised ramuli was dependent on irradiance. Regeneration rate was the highest under 50 ${\mu}$molm$^{-2}$s$^{-1}$ at 2$0^{\circ}C$. Under the conditions of different combinations of temperature (18, 22, 25, 28 and 1$^{\circ}C$) and irradiance (10, 20, 40, 60 and 100 ${\mu}$molm$^{-2}s$ $^{-1}$) regimes, regeneration of excised erect branch was highly affected by temperature and irradiance. The highest regeneration occurred at 25 $^{\circ}C$ and 20 ${\mu}$molm$^{-2}s$$^{-1}$, whereas the highest growth in length (4.5${\pm}$1.0 cm) and fresh weight (1.2${\pm}$0.7 g) was attained after 15 days of culture.

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