• Title/Summary/Keyword: 천공 조건

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Effect of Drainage Methods on Machine Workability and Rice Growth for Dry Seeding in Paddy Soil (벼 건답직파시(乾畓直播時) 배수방법(排水方法)이 기계화조건(機械化條件)과 수도생육(水稻生育)에 미치는 영향(影響))

  • Yoo, Chul-Hyun;Yang, Chang-Hyu;Lee, Kyung-Bo;Shin, Bog-Woo;Kim, Sun-Kwan;So, Jae-Don;Rhee, Gyeong-Soo
    • Korean Journal of Soil Science and Fertilizer
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    • v.27 no.2
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    • pp.117-124
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    • 1994
  • A study was conducted to dectermine the days with optimum soil moisture after drainage or rain for machine workability and seeding establishment on dry seeding in paddy soils(Jeon buk Series, Haplaquepts). The results are summarized as follows. 1. The possible days of tractor-rotary plough were 5days or more for non-mole hole plot(control). The possible days were 2~4days and the optimum days were 5~6days for mole hale plat. 2. The ratio of soil clod(<1cm) was 1 % and 15% for control and mole hole plats, respectively. The optimum soil moisture range for seeding establishment was 31~32% in this soils. 3. The possible days of combine harvesting work were 9days and 5days after drainage for control and mole hole plots, respectively. 4. Soil physical properties were improved but soil organic matter calcium and magnesium in the soil were decreased in the mole hole plats. 5. Yield was 415kg/10a at seeding after 6day drainage in control and 440kg/10a at seeding after 4day drainage in the mole plots.

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Prolongation of Cherry Tomato Shelf-life Using Perforated Film Packaging (천공필름을 이용한 방울 토마토의 저장 수명 연장에 관한 연구)

  • Choi, Won-Seok;Hwang, Kwon-Tack;Kim, Ki-Myong
    • Food Science and Preservation
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    • v.16 no.2
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    • pp.139-146
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    • 2009
  • Whole and stem-off cherry tomatoes were packaged using perforated films(LF05, LF10, LF20, and LF40). Gas composition(ethylene, $O_2$, and $CO_2$), firmness(compression and penetration force), color, brix degree, acidity, and total microbial counts were assessed during storage at $10^{\circ}C$ and 85% relative humidity. Gas composition varied with film gas permeability, indicating that modified atmospheric(MA) conditions were achieved. Firmness fell during storage; samples packed using LF05 showed the lowest firmness, corresponding to low gas transmission conditions. L(lightness) and a(redness) values respectively decreased and rose slightly with increasing storage time, but the b(yellowness) values fell notably. Film permeability significantly affected acidity and soluble solid levels. When LF40 packaging was used, acidity and brix scale changes were similar to those seen after PET container packaging. Total microbial counts increased with time after packaging in most films, and pretreatment differences were not significant. Microflora varied between stem on/off tomatoes. Skin wrinkling and juice appearance were common in tomatoes stored in PET containers and LF films of low gas permeabilities(LF05, LF10, and LF20). White molds were partially found on stem-on tomatoes stored using packaging systems. When film packagings were compared, LF40 was optimal, permitting minimal pretreatment yet offering maximal sanitation.

Effect of Antimicrobial Microperforated Film Packaging on Extending Shelf Life of Cluster-type Tomato (Lycopersicon esculentum Mill.) (천연 항균물질 미세천공필름 포장이 송이토마토의 품질에 미치는 영향)

  • Lee, Youn-Suk;Lee, Young-Eun;Lee, Jung-Soo;Kim, Young-Shik
    • Horticultural Science & Technology
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    • v.29 no.5
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    • pp.447-455
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    • 2011
  • To investigate the effects of the improvement of postharvest quality on fresh tomato, antimicrobial microperforated (AMP) films were prepared and their antimicrobial abilities were observed. AMP films were made by coating different types of natural antimicrobial agents such as cinnamon, clove, and clary sage essential oils into microperforated (MP) films. Cinnamon essential oil of 10% (v/v) has proven to be very effective as inhibitor of the mold growth on tomato, compared to the clove and clary sage essential oils. Quality changes of fresh tomatoes packed using the natural AMP films (AMP10 and AMP30) and MP films (MP10 and MP30) during storage were evaluated. Total microbial growth, weight loss, firmness, lycopene content, and decay rate as the major quality parameters were monitored over 9 days at $15^{\circ}C$. The oxygen transmission rates and mechanical properties between the natural AMP and MP films were also compared. There was no significant difference in change of oxygen transmission rate, tensile strength and elongation between the AMP and MP films. For storage studies, the freshness of tomato packaged in AMP30 film was higher than that in OPP film (the control), MP10, MP30, and AMP10 films. Especially, AMP30 film exhibited high efficiency compared to the control for tomato decay during storage periods. Based on the results, the microperforation and antimicrobial properties of the packaged films may significantly affect the maintenance of an optimum gas composition within the package atmosphere for increasing the storage life and quality of produce. They were also effective on the inhibition of microbial growth by controlled release of antimicrobial agent at an appropriate rate from the package into the tomato. Natural antimicrobial agent coating microperforated films could use potential functional package as a method of extending the freshness of postharvest tomato for storage.

New tunnel reinforcement method using pressurized cavity expansion concept (천공홀 가압 팽창 개념을 도입한 터널 보조 신공법 연구)

  • Cho, In-Sung;Park, Jeong-Jun;Kim, Jong-Sun;Lee, In-Mo
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.12 no.6
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    • pp.407-416
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    • 2010
  • A new tunnel auxiliary method is proposed in this paper which utilizes the concept of cavity expansion for tuunel reinforcement by forming an umbrella arch on the roof of tunnel. When an inflatable pipe is inserted and expanded by pressure in the bore hole of umbrella arch, the ground around the bore hole can be compacted so that the stress condition above the tunnel perimeter is favorably changed. In order to verify the reinforcement effect of new concept, pilot-scale chamber test, trapdoor test and numerical analysis were performed and compared. In pilot-scale chamber test, three types of inflatable pipes are tested to verify the capability of expansion, and the results arc compared with analytical results obtained by applying cavity expansion theory and with results obtained from finite clement analysis, and the experimental results showed agreeable matches with analytical and numerical ones. Numerical analysis of a tunnel and trapdoor test applied with the inflatable pipes are also performed to figure out the reinforcement effect of the proposed techniques, and the results implied that the new method with 3 directional inflatable pipe (no pressure to downward direction) can contribute to reduce tunnel convergence and face settlement.

Optimization of Flow Path of Drill Bit Using CFD Simulation (CFD를 이용한 굴착용 천공드릴비트의 유로 최적화에 관한 연구)

  • Song, Chang-Heon;Kwon, Ki-Beom;Park, Jin-Young;Shin, Dae-Young;Cho, Jung-Woo
    • Tunnel and Underground Space
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    • v.22 no.4
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    • pp.257-265
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    • 2012
  • In this study, a series of CFD (Computational Fluid Dynamics) simulations carried out to evaluate the optimum design model of the internal flow path of drill bit. The Star-CCM+ code was adopted to simulate the multi-phase discharge flow of rock particles and flushing air during a drilling process. The input parameters for the flow simulation of rock particles and air were obtained from the in-situ drilling test results. After the three design factors were determined, the experimental design method (Taguchi method) was utilized to evaluate the optimum value of each factor.

Numerical Study on Ground Vibration Reduction and Fragmentation in a Controlled Blasting Utilizing Directional U Shape Charge Holder (U형 장약홀더를 이용한 발파공법에서 지반진동 저감특성 및 파괴효율에 관한 수치해석적 연구)

  • Kim, Hyon-Soo;Baek, Beom-Hyun;Oh, Se-Wook;Han, Dong-Hun;Cho, Sang-Ho
    • Explosives and Blasting
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    • v.34 no.1
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    • pp.11-18
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    • 2016
  • It is necessary to minimize ground vibration and noise due to blasting work in urban environment. The blast induced ground vibration and noise are generally generated by a portion of detonation energy, where most of the energy is utilized for rock breakage and movement of rock mass. Recently a blast method utilizing U-shaped steel charge holder was suggested to reduce the ground vibration without decreasing destructive power toward the free surface. In this study, single hole blasting utilizing U-shaped steel charge holder were simulated and the stress waves caused by the detonation of explosives were monitored using AUTODYN software. In order to examine the fragmentation efficiency of the U-shaped steel charge holder, one free face blasting models which adapt the blast induced stress waves were simulated by dynamic fracture process analysis (DFPA) code. In addition, the general blasting models were also simulated to investigate the fragmentation effectiveness of the U-shaped steel charge holder in rock blasting.

An Experimental Study on Drilling Conditions for the Instrumentation of Nuclear Fuel (핵연료 계장을 위한 천공조건에 대한 실험적 연구)

  • Hong, Jintae;Kim, Ka-Hye;Jeong, Hwang-Young;Ahn, Sung-Ho;Joung, Chang-Young
    • Journal of the Korean Society for Precision Engineering
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    • v.30 no.1
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    • pp.113-119
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    • 2013
  • To develop a new nuclear fuel, it needs to make a test fuel rod and carry out burn-up test in the test loop of a research reactor to check the irradiation characteristics of the nuclear fuel. At that time, several sensors such as thermocouples, LVDTs and SPNDs are needed to be attached in and out of the fuel rod and connect them with instrumentation cables. Then, the instrumentation cables deliver the signals measured by the sensors to the measuring device located outside of the reactor pool. In particular, to install a thermocouple in a fuel rod, it needs to drill off holes on the alumina blocks and sintered $UO_2$ pellets. However, because the hardness of a sintered $UO_2$ pellet is 700 Hv (or HRC 61) and that of an alumina block is 1480 Hv, a special drilling machine which adapts a diamond coated drill bit had developed. In this study, several case experiments have been carried out to find an optimal drilling condition of the drilling machine. And, using the optimal drilling condition, minimum numbers of the holes that a drill bit can drill off are verified.

EPMA Analysis of Inter-reaction Layer in Irradiated U3Si-Al Fuels (EPMA를 이용한 U3Si/Al 조사 핵연료의 반응층 분석)

  • Jung, Yang-Hong;Yoo, Byung-Ok;Kim, Hee-Moon;Park, Jong-Man;Kim, Myung-Han
    • Analytical Science and Technology
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    • v.17 no.4
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    • pp.355-362
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    • 2004
  • Fission products and Inter reaction layer of $U_3Si-Al$ dispersion fuel, irradiated in HANARO research reactor with 121 kW/m of maximum liner power and 63 at% of average burn-up, was characterization by EPMA (Electron Probe Micro Analyzer). The fuel punching system developed by Irradiated Materials Examination Facility (IMEF) has used to make these samples for the EPMA. With this system a very small and thin specimen which is 1.57 mm in diameter and 2 mm in thickness respectively has been fabricated to protect the EPMA operator from high radioactive fuel and to mini-mize the equivalent dose rate less than 150 mSv/h. EPMA was performed to observe layers of sectional, Inter-reaction and oxide with specimens of cutting and polished. Stoichiometry in the Inter-reaction layer with $16{\mu}m$ of thickness was $U_{2.84}$ Si $Al_{14}$ with calibration of $UO_2$ and $U_{3.24}$ Si $Al_{14.1}$ with calibration of standard specimen. metallic precipitates in this layer were not observed using fission products examination.

Study on the Evaluation Criteria of Termite Dust for Rapid Control of Wooden Structures Damaged by Termites (흰개미 가해 목조건축물의 급속 방제를 위한 분말형 약제(Termite Dust) 평가 기준 연구)

  • Im, Ik Gyun;Chung, Yong Jae
    • Journal of Conservation Science
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    • v.35 no.3
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    • pp.227-235
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    • 2019
  • In Korea, various methods are applied to prevent wooden structures from being damaged by termites. However, since there is no way to quickly bring toxic substances in contact with the termites inside the timber, it leads to the damage of wooden cultural property due to the prolonged period of controlling the termites. Accordingly, an indoor evaluation criteria study was conducted for the introduction of powder-type termiticides in Korea, which produced rapid control effects by drilling wood and directly contacting and transferring toxic substances inside the timber. First, contact toxicity and transfer ability of termite dusts were evaluated to establish the criteria for evaluation of effectiveness against Reticulitermes speratus. The contact toxicity confirmed 100% mortality of fipronil, deltamethrin and cyfluthrin termite dusts within 24 h of contact; however, differences occurred in the active ingredient transfer time to the sublethal. In addition, in the case of transfer ability evaluation, the rate of mortality gradually decreased under 1:9 and 1:25 ratio conditions; however, the difference in the reduction rate was identified depending on the type of termite dust. the results of the evaluation of compressive strength of the wood showed that the difference in the measured values between the control group and the conditions of perforation 1 to 3 times, which does not significantly affect the compressive strength of wood. In this study, the criteria of termite dust selection and evaluation method of dust-type termiticides were presented and the applicability of the method was identified.