• Food Science and Biotechnology
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• 제14권5호
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• pp.566-571
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• 2005

Process of screw-pumping system (SPS) was optimized for mass production of encapsulated bifidus. SPS entrapment device was composed of feeding component, with optimized nozzle size and length of 18G (0.91 cm) and 4 mm, respectively, screw pump, and 37-multi-nozzle. Screw component had five wing turns [radius (r)=26 to 15 mm] from top to bottom of axis at 78-degree angle from middle of the screw, and two wings were positioned at screw edge to push materials toward nozzle. For nozzle component, 37 nozzles were attached to 20-mm round plate. Air compressor was attached to SPS to increase productivity of encapsulated bifidus. This system could be operated with highly viscous (more than 300 cp) materials, and productivity was higher than $1128\;{\pm}\;30\;beads/min$. Viability of encapsulated bifidus was $5.45\;{\times}\;10^8\;cfu$/bead, which is superior to that of encapsulated bifidus produced by other methods ($2.51{\times}10^8\;cfu$/bead). Average diameter of produced beads was $2.048\;{\pm}\;0.003\;mm$. Survival rate of SPS-produced encapsulated bifidus was 90% for Simulator of the Human Intestinal Microbial Ecosystem test and 88% in fermented milk (for 14 days). These results show SPS is effective for use in development of economical system for mass production of viable encapsulated bifidus.

• 농업과학연구
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• 제5권1호
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• pp.29-34
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• 1978

Gun-type nozzle에 있어서 입자(粒子)의 미립화(微粒化)를 개선(改善)코저 절선속도(切線速度)를 증가(增加)하는 방법(方法)의 일환(一環)으로 Screw 중자(中子)를 제작(製作) 장치(裝置)한 Nozzle로 실내(室內)에서 분무실험(噴霧實驗)한 결과(結果) 다음과 같은 결론(結論)을 얻었다. 분무입자(噴霧粒子)의 직경(直徑)이 클수록 분무도달거리(噴霧到達距離)는 컸으며 Screw중자(中子)를 장치(裝置)하였을 때가 장치(裝置)하지 않았을 때에 비(比)하여 분무입자(噴霧粒子)의 미립화(微粒化)는 현저히 양호(良好)하였고 분무도달거리(噴霧到達距離)는 분구(噴口)가 소구경시(小口徑時)에는 거의 차이(差異)가 없었으나 분구(噴口)가 증대(增大)함에 따라서 현저히 짧아졌다. 최고(最高) 도달거리(到達距離) 지점(地點)부터 1~2m의 분무도달거리(噴霧到達距離)에 있어서는 기류부유이동(氣流浮遊移動)의 현상(現象)으로 분무입자(噴霧粒子)가 작아졌다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.1234-1239
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• 2003

A failure analysis of holddown spring screw was performed using fracture mechanics approach. The spring screw was designed such that it was capable of sustaining the loads imposed by the initial tensile preload and operational loads. In order to investigate the cause of failure, a stress analysis of the top nozzle spring assembly was done using finite element analysis and a life prediction of the screw was made using a fracture mechanics approach. The elastic-plastic finite element analysis showed that the local stresses at the critical regions of head-shank fillet and thread root significantly exceeded than the yield strength of the screw material, resulting in local plastic deformation. Primary water stress corrosion cracking life of the Inconel 600 screw was predicted by using integration of the Scott model and resulted in 1.42 years, which was fairly close to the actual service life of the holddown spring screw.

• Journal of Biosystems Engineering
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• 제34권3호
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• pp.167-174
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• 2009

This study was conducted to develop an agaricus bisporus washing machine which uses compressed air to remove foreign materials attached on the surface of agaricus bisporus. A prototype of the washing machine was constructed, and performance of removing foreign materials was tested. Research results are as follows: 1. Several transferring methods including PE roller rotation, brush roller rotation, PE screw rotation, vibration plate, and belt conveyor were evaluated. Roller, screw, and vibration methods caused damages on the surface of the products, but belt conveyor method caused the least damages. 2. For air jet, a stationary nozzle type and a rotational type were evaluated. The best air jet nozzle was the jet-type nozzle, and the rotational type was more effective than stationary type nozzle. 3. With the conveyer belt, box type moving method and the rotational air jet nozzle, the washing machine showed the best performance when higher than 5.4${\times}$105 Pa of air jet pressure and lower than 0.047 m/s of moving speed was used. Working performance of the system was 650 kg/h, and the damaging rate was 1.2 %.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.7-12
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• 2004

A lifetime prediction of holddown spring screw in nuclear fuel assembly was performed using fracture mechanics approach. The spring screw was designed such that it was capable of sustaining the loads imposed by the initial tensile preload and operational loads. In order to investigate the cause of failure and to predict the stress corrosion cracking life of the screw, a stress analysis of the top nozzle spring assembly was done using finite element analysis. The elastic-plastic finite element analysis showed that the local stresses at the critical regions of head-shank fillet and thread root significantly exceeded than the yield strength of the screw material, resulting in local plastic deformation. Normalized stress intensity factors for PWSCC life prediction was proposed. Primary water stress corrosion cracking life of the Inconel 600 screw was predicted by using integration of the Scott model and resulted in 1.78 years, which was fairly close to the actual service life of the holddown spring screw.

• 대한환경공학회지
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• 제37권1호
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• pp.23-33
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• 2015

본 연구는 물탱크 내부의 사류구역 최소화에 목적을 두고 진행하였으며 입수관의 형태를 개선하여 물탱크 내부에서 발생하는 유동특성을 전산유체역학(Computational Fluid Dynamics, CFD)모사 기법을 이용하여 분석 하였다. 기존에 물탱크에 사용되던 자유낙하 방식의 입수관을 다공형 스크류 노즐 입수관으로 개선하고 유동 특성을 분석한 결과 노즐 안에 스크류 날개가 설치된 경우 유동흐름의 폭이 넓게 분사 되었으며 원통형 물탱크 내부에서도 넓은 유동 흐름이 나타났다. 또한 사각형 물탱크에 다공형 스크류 노즐 입수관이 1개 설치되어 있을 경우와 2개 설치되어있을 경우의 유동해석과 추적자모의를 수행하였으며 그 결과 입수관을 2개 설치할 경우 MODAL, MORILL index값이 1에 가깝게 나타나 Plug Flow 특성에 근접하단 결과를 얻을 수 있었다.

• 대한기계학회논문집B
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• 제41권1호
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• pp.29-36
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• 2017

본 논문은 환형노즐 이젝터를 이용하여 세정수 공급과 기포생성을 동시에 할 수 있는 세정기술 개발을 위한 기초연구를 목적으로 한다. 환형노즐 이젝터의 피치변화에 따른 구동 및 부유체의 정량적 유동특성과 세정수조에 분출되는 분류의 정성적 가시화 이미지를 분석하였으며, 세정물의 농약 잔류물 성분의 농도를 검증하였다. 피치가 증가하면 구동유량은 증가하는 반면에, 유량비는 감소하였다. 피치가 증가하면 분류는 부력분류나 평형분류 거동을 나타내며, 잔류농약의 농도는 감소 후 증가하였다.

• 한국정밀공학회지
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• 제31권11호
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• pp.1031-1040
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• 2014

In this paper, a new condition diagnosis algorithm for the lens injection molding process using various features extracted from cavity pressure, nozzle pressure and screw position signals is developed with the aid of probability neural network (PNN) method. A new feature extraction method is developed for identifying five (5), seven (7) and two (2) critical features from cavity pressure, nozzle pressure and screw position signals, respectively. The node energies extracted from cavity and nozzle pressure signals are also considered based on wavelet packet decomposition (WPD). The PNN method is introduced to build the condition diagnosis model by considering the extracted features and node energies. A series of the lens injection molding experiments are conducted to validate the model, and it is demonstrated that the proposed condition diagnosis model is useful with high diagnosis accuracy.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2003년도 생물공학의 동향(XII)
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• pp.750-753
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• 2003

본 실험은 Bifidus균의 위 장관 내 공급 시 균의 사멸에 대한 안정성을 높이기 위해 제조하는 microcapsule화 된 비드의 생산성을 향상시킬 목적으로 실시하였다. Bifidus균의 세포 포집 시 유사 위액과 담즙산에 높은 생존률을 보인 것으로 조사된 여러 종류 첨가물의 최적 농도로 비드를 제조하였을 때, material의 점도가 멸균 후 300cp 이하로 감소하였으며, cell 첨가 시 alginate bead 제조 한계 점도인 300cp 부근까지 증가하였다. 이상의 조건에서 고 점도의 alginate solution을 이송, 압출할 수 있는 SPS를 구성하였다. 비드의 생산성 비교 실험에서 18G, 4mm 규격의 nozzle을 13개 장착한 multi-nozzle은 $308{\pm}3ea/min$ 의 생산성을 보였으며 airgun 및 sylinge를 이용해 제조한 경우보다 각각 2.18배, 14.09배의 생산량 증대효과를 얻을 수 있었다.

• 한국물환경학회지
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• 제34권2호
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• pp.173-182
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• 2018

Reservoirs, facilities to store water, are being used in several fields for their ability to hold back a large quantity of water for a long time before the water is actually used. However, at the same time, the reservoirs are considered to have a flaw: the longer they store water, the more the quality of water in these reservoirs deteriorates. Further, when the reservoirs are large, they are more likely to have dead-water regions in out-of-the way spots far from either an in-current or an ex-current canal. This study conducted a Computational Fluid Dynamic (CFD) simulation and tried to figure out the internal flow inside each of the reservoirs with different in-current canals built by the multiple hoe screw nozzle method and the drop in-current method. The drop in-current method is more frequently used. According to the analysis of the internal flow inside each reservoir with the different methods applied, we found that the reservoir with the drop in-current canal would have two rotary currents in the lower region of the reservoir and that the velocity of flow would decrease. For a reservoir with the screw nozzle method, a single rotary current occurred, and inside the reservoir, regardless of height, the current turned out to flow in a regular manner.