• Asian-Australasian Journal of Animal Sciences
• /
• 제25권3호
• /
• pp.410-420
• /
• 2012

A trial was conducted to: i) evaluate the BW growth, energy intakes and energetic efficiency of pigs fed high and low density diets from 27 to 141 kg BW, ii) evaluate sire line and sex differences when fed both diets, and iii) to compare ME to NE as predictor of pig performance. The experiment had a replicated factorial arrangement of treatments including four sire lines, two sexes (2,192 barrows and 2,280 gilts), two dietary energy densities and a light or heavy target BW, 118 and 131.5 kg in replicates 1 to 6 and 127 and 140.6 kg in replicates 7 to 10. Pigs were allocated to a series of low energy (LE, 3.27 Mcal ME/kg) corn-soybean meal based diets with 16% wheat midds or high energy diets (HE, 3.53 to 3.55 Mcal ME/kg) with 4.5 to 4.95% choice white grease. All diets contained 6% DDGS. The HE and LE diets of each of the four phases were formulated to have equal lysine:Mcal ME ratios. Pigs were weighed and pen feed intake (11 or 12 pigs/pen) recorded at 28-d intervals. The barrow and gilt daily feed (DFI), ME (MEI) and NE (NEI) intake data were fitted to a Bridges function of BW. The BW data of each sex were fitted to a generalized Michaelis-Menten function of days of age. ME and NE required for maintenance (Mcal/d) were predicted using functions of BW (0.255 and 0.179 BW^0.60 respectively). Pigs fed LE diets had decreased ADG (915 vs. 945 g/d, p<0.001) than pigs fed HE diets. Overall, DFI was greater (p<0.001) for pigs fed the LE diets (2.62 vs. 2.45 kg/d). However, no diet differences were observed for MEI (8.76 vs. 8.78 Mcal/d, p = 0.49) or NEI (6.39 vs. 6.44 Mcal/d, p = 0.13), thereby indicating that the pigs compensated for the decreased energy content of the diet. Overall ADG:DFI (0.362 vs. 0.377) and ADG:Mcal MEI (0.109 vs. 0.113) was less (p<0.001) for pigs fed LE compared to HE diets. Pigs fed HE diets had 3.6% greater ADG:Mcal MEI above maintenance and only 1.3% greater ADG:Mcal NEI (0.152 versus 0.150), therefore NEI is a more accurate predictor of growth and G:F than MEI.Pigs fed HE diets had 3.4% greater ADG:Mcal MEI and 0.11% greater ADG:NEI above maintenance than pigs fed LE diets, again demonstrating that NEI is a better predictor of pig performance than MEI. Pigs fed LE diets had similar daily NEI and MEI but grew slower and less efficiently on both ME and NE basis than pigs fed HE diets. The data suggest that the midds NE value (2.132 Mcal/kg) was too high for this source or that maintenance was increased for pigs fed LE diets.

• Journal of Electrochemical Science and Technology
• /
• 제12권1호
• /
• pp.101-111
• /
• 2021

To improve the potential of single chamber microbial fuel cells (SCMFCs) as an applicable technology, the main challenge is a practical application for larger scales bioenergy production from potent exoelectrogenic microorganism with real dairy wastewater. To increase power generation, three individual MFCs were together operated in series best under the fed batch condition for 15 days. The volume of MFC 1 and MFC 2 is "300 mL" and MFC 3 is "500 mL" respectively. The individual MFCs 1, MFC 2 and MFC 3 gives an open circuit voltage of 0.60 V, 0.66 V and 0.55 V and result in total working voltage when connected in series of 1.745V, which lead an LED to glow. The maximum power densities obtained from MFC 1, MFC 2 and MFC 3 are 62 mW/㎡, 50 mW/㎡ and 45 mW/㎡ (normalized to the surface area of the anodic electrode, which was 50 ㎠ for all three MFCs), and corresponding to current densities of 141 mA/㎡, 155 mA/㎡ and 123 mA/㎡, respectively. Therefore this work suggests the cheapest way to connect microbial fuel cells in series to gain power with the lowest operating cost and chemical oxygen demand (COD) removal.

• Progress in Superconductivity
• /
• 제5권2호
• /
• pp.128-131
• /
• 2004

The resistive superconducting fault current limiters (SFCLs) are very attractive devices for the electric power network. But they have some serious problems when the YBCO thin films were used for the current limiting materials due to the in homogeneities caused by manufacturing process. When the YBCO films have some inhomogeneities, simultaneous quenches are difficult to achieve when the fault current limiting units are connected in series for increasing operating voltage ratings. Magnetic field application is one of the prospective way of inducing simultaneous quenches far the series-connected resistive FCL components. Magnetic field was typically generated by the fault current thorough a coil, which is connected to components of the fault current limiter in series, leaving the problem, which provides significant inductance to the power line and suppresses critical current density of the superconducting components. In this article we investigated the possible application of the protective current transformer (p-CT), which is available current source to the magnetic coil. This system inductively coupled to the circuit, therefore, remarkably reducing impedance to the circuit. The current by the protective current transformer was directly fed to the coil, generating magnetic field large enough to reduce critical current density of the components. This successfully induced simultaneous quenches of the series-connected resistive FCL components.

• 한국양식학회지
• /
• 제13권2호
• /
• pp.153-161
• /
• 2000

10종의 부착성 규조류를 대상으로 참전복 치패의 먹이효율을 조사하였다. 유생의 부착율을 실험 1에서 Rhaphoneis sp.가 31.6%, 실험 2에서는 P. tricornutum가 16.4%로 가장 높았다. 부착성 규조류를 먹이로 한 치패의 생존율은 실험1에서 Raphoneis sp.가 62.7%로 가장 높았고, N. incerta, C. schroderi, N. closterium 는 각각 56.8%, 55.2%, 54.3%로 비교적 높았으며, Navicula sp. (B-38)는 30.5%로 가장 낮았다. 그리고 실험 2와 3에서는 C. schroderi, N. incerta, P. tricornutum 및 Raphoneis sp.는 높은 생존율을 보였으며, 특히 C. schroderi는 67.6%, 49.4%로 가장 높았다. 반면, H. marina (40.4%, 15.7%), Nitzschia sp. (39.1%, 27.1%), N. closterium (35.2%, 18.0%)은 비교적 낮았다. 치패의 성장에 있어서 일간성장량은 부착율과 생존율이 높았던 C. schroderi에서 최고 83.3 ${\mu}$m로 가장 높았고, 생존율이 낮았던 H. marina와 N. closterium은 19.9~38.7 ${\mu}$m로 가장 낮은 일간성장량을 보였다.

• Journal of Nutrition and Health
• /
• 제31권5호
• /
• pp.914-920
• /
• 1998

The effect of dietary pectin, tangerine pulp meal, propionate, lactate or fumarate on cholesterol (C) and triacylglycerol(TG) levels in the serum and liver, and the effect of pectin on dietary C absorption were studied in a series of three experiments. Mature female Sprague Dawley rats were fed a control diet or diets containing 5% pectin, 5% tangerine pulp meal, 3% propionate, 3% lactate 3% fumarate, or 10% pectin. Serum total C levels were lower(p<0.05) in rats fed the diet containing 5% pectin than in control rats after a 4-week feeding period(93.8 vs 119.2mg/100mL). Serum HDL, LDL+VLDL C levels were not different among diet groups. Liver total C level was also lower(p<0.05) in rats fed the diet containing 5% pectin than in control rats, but liver TG level was not influenced by diet. Dietary propionate, lactate or fumarate did not reduce serum C, indicating that propionate is not a regulator of serum C. However, dietary pectin(10%) increased fecal excretion of dietary C(or its metabolites) more than 70% over a control value. Our data indicate that dietary pectin reduces serum and liver C levels by increased fecal secretion of dietary C, but not by its fermentation product propionate or other gluconeogenic substrates. (Korean J Nutrition 31(5) : 914∼920, 1998)

• Nutritional Sciences
• /
• 제2권2호
• /
• pp.65-70
• /
• 1999

Feeding rats a diet containing bean-hull causes hypertropy in their parotid glands due to the high tannin content. The amount of feedintake of rats led bean-hull was higher than that of rats fed a standard diet. However, the increase in body weight of rats fed bean-hull was lower than that of rats fed a standard diet, which resulted in significantly low feed efficiency of the bean-hull containing diet. Within one week, parotid glands significantly enlarged and a series of proline-rich proteins (PRPs) were produced, which were similar to those induced by feeding high-tannin sorghum with flight differences in molecular weights. Even though the direct comparison between PRPs produced by the bean-hull containing diet and those induced by the high sorghum diet is not appropriate due to laboratory inconsistences, several new PRPs were produced by high tannin diets in both experiments. Differences in molecular weights of PRPs induced in two different tannin sources must be funker investigated to be fully characterized. These morphological and biochemical changes have now been demonstrated to occur in response to the ingestion of tannins, presumably to diminish the anti-nutritional effects of tannins.

• 대한전자공학회논문지TC
• /
• 제41권12호
• /
• pp.93-102
• /
• 2004

본 논문은 개구면 결합 공진기 급전 마이크로스트립 패치 안테나에 대하여 간결하면서도 정확한 등가회로 모델을 추출하기 위한 일반적인 전자기 이론을 제안하였다. 그리고 등가회로는 이상적인 트랜스, 어드미턴스, 그리고 전송선으로 구성된다. 관련소자들의 값은 복소전력 개념, Fourier 변환, Fourier 급수, 그리고 spectral-domain immittance-approach를 적용하여 계산된다. 본 논문에서는 이 방법을 이용하여 안테나의 입력 임피던스를 구하고, 기존 논문에서 발표된 계산값, 그리고 측정값들과 비교하였다. 기존의 연구 결과와의 정확한 일치는 본 논문이 제안한 등가회로 모델의 간결성과 정확성을 입증해 준다.

• Journal of Electrical Engineering and Technology
• /
• 제3권2호
• /
• pp.224-234
• /
• 2008

Multi-phase machines can be used in variable speed drives. Their applications include electric ship propulsion, 'more-electric aircraft' and traction applications, electric vehicles, and hybrid electric vehicles. Multi-phase machines enable independent control of a few numbers of machines that are connected in series in a particular manner with their supply being fed from a single voltage source inverter(VSI). The idea was first implemented for a five-phase series-connected two-motor drive system, but is now applicable to any number of phases more than or equal to five-phase. The number of series-connected machines is a function of the phase number of VSI. Theoretical and simulation studies have already been reported for number of multi-phase multi-motor drive configurations of series-connection type. Variable speed induction motor drives without mechanical speed sensors at the motor shaft have the attractions of low cost and high reliability. To replace the sensor, information concerning the rotor speed is extracted from measured stator currents and voltages at motor terminals. Open-loop estimators or closed-loop observers are used for this purpose. They differ with respect to accuracy, robustness, and sensitivity against model parameter variations. This paper analyses operation of an MRAS estimator based sensorless control of a vector controlled series-connected two-motor five-phase drive system with current control in the stationary reference frame. Results, obtained with fixed-voltage, fixed-frequency supply, and hysteresis current control are presented for various operating conditions on the basis of simulation results. The purpose of this paper is to report the first ever simulation results on a sensorless control of a five-phase two-motor series-connected drive system. The operating principle is given followed by a description of the sensorless technique.

• 대한전자공학회논문지
• /
• 제25권5호
• /
• pp.536-541
• /
• 1988

The push-pull current-fed DC-to-DC converter has only one energy storage reactor in series with the input for any number of outputs. It is considered that this property of the converter has considerable advantages over other multiple-output circuits. The steady state characteristics of the converter with two outputs is analyzed. It is known that the voltage difference between the two outputs appears by existing the 2nd winding resistance of transformer and there is a region of the duty ratio in which the voltage difference of the converter is smaller than that of the forward converter.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2004년도 ICCAS
• /
• pp.238-242
• /
• 2004

The paper describes an automatic frequency control current-fed inverter for forging applications. The IGBT in series with diodes as its switching devices in the inverter circuit which is of full-bridge type. The operating frequency is automatically tracked to maintain a small constant leading phase angle when load parameters change. The load voltage is controlled to protect the switches. The output power can be adjusted by varying the input current from phase controlled rectifiers which is a part of current source. The system has been operated at 15-17 kHz. The output power transferred to the load is 1,595 watts. It can heat the steel work pieces with 15 mm diameter and 120 mm long from room temperature to approximately 1100 $^{\circ}C$ within 20 seconds with 0.97 leading power factor on the input side.