• Asian-Australasian Journal of Animal Sciences
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• 제20권8호
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• pp.1236-1242
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• 2007

Sixty healthy growing pigs ($Duroc{\times}Landrace{\times}Yorkshire$ with an average BW of 21.4 kg) were used to determine the true digestible phosphorus (TDP) requirement of growing pigs on the basis of growth performance and serum biochemical indices. Pigs were assigned randomly to one of five dietary treatments (12 pigs/diet), representing five levels of TDP (0.16%, 0.20%, 0.23%, 0.26% and 0.39%). There were three replications per treatment, with four pigs (2 barrows and 2 gilts) in each replication (2 pigs/pen) A randomized-block design was used, with pen as the experimental unit. Experimental diets were formulated to provide the 5 TDP levels with a total calcium (Ca) to TDP ratio of 2:1, and offered to pigs at 5% BW for 28 d. The total Ca contents of the five diets were 0.33, 0.38, 0.45, 0.51 and 0.79%, respectively. During the 28-d experimental period, the ADG of pigs was affected by dietary TDP levels as described by Equation 1: y = $-809,532x^4+788,079x^3-276,250x^2+42,114x-1$,759; ($R^2$ = 0.99; p<0.01; y = ADG, g/d; x = dietary TDP, %). The feed:gain ratio for pigs was affected by dietary TDP levels as described by Equation 2: y = $3,651.1x^4-3,480.4x^3+1,183.8x^2-172.5x+10.9$ ($R^2$ = 0.99; p<0.01; y = feed:gain ratio; x = dietary TDP, %). Total P concentrations in serum were affected by dietary TDP levels as described by Equation 3: y = $-3,311.7x^4+3,342.7x^3-1,224.6x^2+195.6x-8.7$ ($R^2$ = 0.99; p<0.01; y = total serum P concentration and x = dietary TDP, %). The highest ADG (782 g/d), the lowest feed:gain ratio (1.07), and the highest total serum P concentration (3.1 mmol/L) were obtained when dietary TDP level was 0.34%. Collectively, these results indicate that the optimal TDP requirement of growing pigs is 0.34% of the diet (e.g., 5.1 g/day for a 30-kg pig that consumed 1.5 kg feed daily) at a total Ca to TDP ratio of 2:1.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.1297-1300
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• 2008

A conventional linear accelerator system requires a flat-topped pulse with less than ${\pm}$ 0.5% ripple to meet the beam energy spread requirements and to improve pulse efficiency of RF systems. A pulse transformer is one of main determinants on the output pulse voltage shape. The pulse transformer was investigated and analyzed with the pulse response characteristics using a simplified equivalent circuit model. The damping factor ${\sigma}$ must be >0.86 to limit the overshoot to less than 0.5% during the flat-top phase. The low leakage inductance and distributed capacitance are often limiting factors to obtain a fast rise time. These parameters are largely controlled by the physical geometry and winding configuration of the transformer. A rise time can be improved by reducing the number of turns, but it produces larger pulse droop and requires a larger core size. By tradeoffs among these parameters, the high-voltage pulse transformer with a pulse width of 10 ${\mu}s$, a rise time of 0.84 ${\mu}s$, and a pulse droop of 2.9% has been designed and fabricated to drive a klystron which has an output voltage of 284 kV, 30-MW peak and 60-kW average RF output power. This paper describes design optimization of a high-voltage pulse transformer for high-power pulsed applications. The experimental results were analyzed and compared with the design. The design and optimal tuning parameter of the system was identified using the model simulation.

• 한국물환경학회지
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• 제26권1호
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• pp.35-43
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• 2010

This experimental design and response surface methodology (RSM) have been applied to the investigation of the electrocoagulation/flotation of dye wastewater. The electrocoagulation/flotation reactions were mathematically described as a function of parameters current (A), NaCl concentration (B), initial RhB concentration (C) and time (D) being modeled by use of the central composite design (CCD). The application of RSM using the CCD yielded the following regression equation, which is an empirical relationship between the RhB removal (%) and test variables in RhB removal (%) = $-300.42+129.21{\cdot}Current+46.99{\cdot}NaCl-0.11{\cdot}RhB-+43.71{\cdot}Time-5.67{\cdot}Current{\cdot}NaCl-3.18{\cdot}Current{\cdot}Time-2.41{\cdot}NaCl{\cdot}Time-19.79{\cdot}Current^2-2.27{\cdot}NaCl^2-1.59{\cdot}Time^2$. the model predictions agreed well with the experimentally observed result ($R^{2}=0.9728$). The estimated ridge of maximum response and optimal conditions for RhB removal (%) using canonical analysis was 99.4% (A: 1,77 A, NaCl concentration: 2.23 g/L, RhB concentration: 56.12 mg/L, Time: 9.98 min). To confirm this optimum condition, three additional experiments were performed and RhB removal (%) were within range of 86.87% (95% PI low)~111.93% (95% PI high) obtained.

• Smart Structures and Systems
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• 제18권1호
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• pp.53-74
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• 2016

This paper presents an experimental study on constructing a tunable secondary suspension for high-speed trains using magneto-rheological fluid dampers (referred to as MR dampers hereafter), in the interest of improving lateral ride comfort. Two types of MR dampers (type-A and type-B) with different control ranges are designed and fabricated. The developed dampers are incorporated into a secondary suspension of a full-scale high-speed train carriage for rolling-vibration tests. The integrated rail vehicle runs at a series of speeds from 40 to 380 km/h and with different current inputs to the MR dampers. The dynamic performance of the two suspension systems and the ride comfort rating of the rail vehicle are evaluated using the accelerations measured during the tests. In this way, the effectiveness of the developed MR dampers for attenuating vibration is assessed. The type-A MR dampers function like a stiffness component, rather than an energy dissipative device, during the tests with different running speeds. While, the type-B MR dampers exhibit significant damping and high current input to the dampers may adversely affect the ride comfort. As part of an ongoing investigation on devising an effective MR secondary suspension for lateral vibration suppression, this preliminary study provides an insight into dynamic behavior of high-speed train secondary suspensions and unique full-scale experimental data for optimal design of MR dampers suitable for high-speed rail applications.

• 한국해안·해양공학회논문집
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• 제30권1호
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• pp.1-9
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• 2018

본 연구에서는 투과성 판을 통과하면서 발생하는 에너지 손실효과를 나타내는 비선형 항력 항을 등가 선형화기법으로 선형화시킨 준선형 모델을 제안하였다. 이 모델을 경계요소법(Boundary Element Method)으로 풀어 2차원 조파수조의 투과성 소파장치를 개발에 활용하였다. 투과성 판에서의 항력계수는 수리 모형실험 결과와 비교를 통해 새롭게 구하였다. 공극률 0.1, 잠긴 깊이 d/h = 0.1, 경사각도 $10^{\circ}{\leq}{\theta}{\leq}20^{\circ}$를 갖는 투과성 소파장치가 전반적으로 우수한 소파성능을 보였다. 개발된 준선형 수치모델은 앞으로 다양한 형태의 투과성 소파장치의 최적 설계에 활용될 것이다.

• 한국식품조리과학회지
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• 제25권2호
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• pp.234-242
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• 2009

This study was performed to find the optimum ratio of ingredients for the manufacture of kiwifruit jam. The experiment was designed according to the D-optimal design of RSM (response surface methodology), which included 18 experimental points with 4 replicates for three independent variables (sugar $35{\sim}60%$, pectin $0.1{\sim}1.0.%$, kiwifruit paste $0.37{\sim}0.90%$). The compositional and functional properties of the prepared products were measured, and these values were applied to mathematical models. A canonical form and trace plot showed the influence of each variable on the quality attributes of the final product mixture. By use of the F-test, viscosity, color values (L, a, b), and sensory characteristics (color) were expressed by a linear model, while the L color value and select sensory characteristics (smell, taste, overall acceptance) were also expressed by a quadratic model. The optimum formulations by the numerical and graphical methods, were similar, and with the numerical method it presented as: sugar, pectin, and barley sproutling powder at 49.7%, 0.5%, and 0.6%, respectively. The above results demonstrate the feasibility of preparing kiwifruit jam added with barley sproutling powder, and therefore, the commercialization of a kiwifruit jam marketed as a functional food is deemed possible.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2012년도 춘계학술대회 논문집
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• pp.861-866
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• 2012

Turbo-charger noise radiated from air intake part is one of the most important noise sources in diesel power plant. In this paper, intake noise control of the diesel power plant was studied using parallel baffle type silencer and concentric hole-cavity resonator simultaneously. Firstly, acoustical characteristics and attenuation performance for parallel baffle type silencer were investigated through theoretical approach and experimental method. Based on the results, optimal design of the parallel baffle silencer was suggested. Secondly, for reducing the low frequency noise contained in the intake noise, the concentric hole-type resonator was developed and the acoustic performance was verified from the test. By combining two types of silencers, it is expected that the overall insertion loss is about 50 dB. So, the combined silencer is very helpful in reducing the intake noise of diesel power plant.

• 대한조선학회지
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• 제27권1호
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• pp.73-83
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• 1990

본 연구에서는 축대칭 전단 유동이 추진기면에 유입될 때의 유효반류 계산 방법을 다루었다. 이는 효율적인 추진기 설계와 추진기에서 발생하는 소음의 감소를 위해 선행되어야 할 분야이다. 계측된 공칭반류를 수학적으로 모델링하고 추진기면은 작동원판으로 이상화하여 선형 운동량 이론에 의해 문제를 정식화하였다, 이에 의해 전단 유동이 고려된 축방향 유효반류를 계산하는 전산프로그램을 개발하였으며 계산된 결과를 실험치 및 Huang 등의 계산 결과와 비교하였다. 계산결과 전단 유동의 영향은 허브로 갈수록 크게 나타났으며 유효반류는 추력 계수가 크고 허브에 가까울수록 다른 결과와 차이를 보이나 추력 계수가 작거나 허브에서 멀어질수록 잘 일치하고 있었다.

• 전자공학회논문지
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• 제53권7호
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• pp.56-63
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• 2016

본 논문에서는 멤브레인 방식 키보드에서 고스트-키를 검출하는 새로운 방법을 제시하였다. 멤브레인 필름에 저항성 도체를 추가로 코팅하는 하드웨어적인 변경을 제시하고, 이때 발생하는 정상-키와 고스트-키에 대한 최적의 검출 저항비에 관해 이론적으로 분석하였다. 저항비는 검출전압 차가 가장 작은 최악의 키 조합에 최적인 비율을 적용하며, 시뮬레이션에 의해 다른 키 조합에 대해서도 이 비율을 적용해 고스트-키를 검출할 수 있음을 보였다. 제시한 방법의 타당성을 입증하기 위해 실험 회로를 구성하고 마이크로프로세서의 아날로그-디지털 변환기를 이용해 전압을 추출하였으며, 그 결과에 따르면 정상-키와 고스트-키 사이에 뚜렷한 전압차가 발생해 멤브레인 방식 키보드에서 발생하는 고스트-키를 확실하게 검출할 수 있음을 확인하였다.

• Journal of Biosystems Engineering
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• 제31권5호
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• pp.436-442
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• 2006

This research was conducted to design and develop a wired monitoring system for judging if sick or dead layers (SDL) exist in multi-tier layers battery (MLB) by machine vision, and to analyze its performance. In this study, 20 Brown Leghorn (Hi-Brown) layers aged 37 weeks old, were used as the experimental animals. The intensity of concern paid by layers on feed was over 90% during 5 minutes and 30 seconds after providing feed, and normal layers (NL) had been standing to take feed for that period. Therefore, in this study, the optimal judging time was set by this test result. The wired monitoring system developed was consisted of a driving device for carrying machine vision systems, a control program, a RS232 to RS485 convertor, an automatic positioning system, and an image capture system. An image processing algorithm was developed to find SDL in MLB by the processes of binary processing, erosion, expansion, labeling, and reckoning central coordinate of the captured images. The optimal velocity for driving unit was set up as 0.13 m/s by the test results for wired monitoring system, and the proximity switch was controlled not to be operated for 1.0 second after first image captured. The wired monitoring system developed was tested to evaluate the remote monitoring performance at lab-scale laying hen house. Results showed that its judgement success.ate on normal cage (without SDL) was 87% and that on abnormal cage (with SDL) was 90%, respectively. Therefore, it would be concluded that the wired monitoring system developed in this study was well suited to the purpose of this study.