• Asian-Australasian Journal of Animal Sciences
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• 제33권6호
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• pp.921-929
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• 2020

Objective: The aim of the present study was to investigate the beneficial effects of dietary supplementation with oil palm frond (leaf) (OPF) with and without oil palm meal (OPM) on nutrient intake and digestibility, ruminal fermentation and growth performance in goats. Methods: Six female crossbred goats were fed for 28 days of 3 diet treatments; 100% para-grass (T1); 50% para-grass + 50% OPF (T2), and 30% para-grass + 50% OPF + 20% OPM (T3). Body weight, rectal temperature, respiratory rate, and urine volume, food intake, dry matter intake and water intake were measured daily. Nutrient digestibility was determined from five consecutive days of last week in each diet. Ruminal fluid, urine and blood were collected at the end for determination of rumen protozoa and volatile fatty acid contents, urinary allantoin excretion, blood cell count and chemistry profiles. Results: Goats fed T2 and T3 showed higher dry matter and nutrients intakes while protein digestibility was suppressed compared with those for T1. Crude fat digestibility declined in T2 but maintained after adding the OPM (T3). High fat intake by giving OPF and OPM corresponded to a higher ruminal acetate/propionate ratio (C2/C3) and serum cholesterol level. An increased urinary allantoin/creatinine ratio was found in T2 and T3 compared with T1, implying an increased number of ruminal microbes. Conclusion: Increased dry matter intake in T2 and T3 suggested that oil palm by-products are partly useful as a replacement for para-grass in goats. Replacement with the by-products increased plasma cholesterol level, which suggested that these products are a useful energy source. Changes in rumen parameters suggested an increased microbial number and activity suitable for acetate production. However, the limited digestibility of protein implies that addition of high protein feeds may be recommended to increase body weight gain of goats.

• Asian-Australasian Journal of Animal Sciences
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• 제15권12호
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• pp.1738-1746
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• 2002

Research was carried out to ascertain whether or not the volume of saliva flowing into the rumen regulates dry forage intake in ruminants. Goats with a parotid fistula were fed roughly crushed alfalfa hay cubes, concentrated beef cattle feed and $NaHCO_3$ wice daily (10:00-12:00, 16:00-18:00). Except for the days on which experiments were conducted, the animals were free access to drinking water. The animals were intraruminally infused every day prior to the morning feeding period with parotid saliva collected from the parotid fistula over a 24 h period. The present experiment consisted of three treatments, non-infusion (NI), intraruminal infusion of parotid saliva (RSI), and intraruminal infusion of warm water (RWI). In the RSI treatment, approximately 4-5 kg of parotid saliva (280-290 mOsm/l) collected over a 24 h period was intraruminally infused 1 h prior to the commencement of morning feeding. In the RWI treatment, parotid saliva was substituted for warm water ($36^{\circ}C$). After infusions, the animals were fed on roughly crushed alfalfa hay cubes for 2 h. During feeding, eating and saliva secretion rates were measured. Blood samples were also periodically collected from the jugular vein. After 2 h feeding, water intake was measured for 30 min. These measurements were used to define thirst levels. On the day of the experiment, the animals were not access to drinking water during the morning feeding. It is thought that rumen fill in RSI and RWI treatments was higher than the NI treatment. In comparison with the NI treatment however, cumulative feed intake increased by 39.3% with RSI treatment and by 45.9% with RWI treatment after completion of the 2 h feeding period. After 2 h feeding, thirst level in the RSI treatment showed only a 10% decrease compared to the NI treatment, but thirst level in the RWI treatment decreased 49.8%. Despite the significant differences in thirst levels between RSI and RWI treatments, the cumulative feed intake in both treatments was similar. When comparing accumulated saliva secretion volumes 2 h after feeding, volumes in the RSI treatment were significantly 35.9% lower than the NI treatment while volumes in the RWI treatment were unchanged. However, the volumes of saliva and fluid flowing into the rumen were greater in both RSI and RWI treatments when compared to the NI treatment. The results indicate that the amount of saliva flowing into the rumen is a factor regulating feed intake in ruminants fed on dry forage.

• 대한토목학회논문집
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• 제32권2A호
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• pp.123-130
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• 2012

증기를 발생시켜 터빈(turbine)을 회전시키는 화력 및 원자력 발전 계통에서 냉각시설은 필수적인 구조물이며, 냉각수 순환 계통은 일반적으로 해수를 취수하여 발전소 내의 복수기까지 유입시켜 증기와 열 교환 후 다시 외해로 배출시키는 형태를 취하고 있다. 최근 냉각수 취 배수 방식을 표층 취 배수 방식이 아닌 심층 취 배수 방식으로 변경하고 있는데, 기존 원전의 재순환 온도에 대한 영향을 최소화 하고, 온배수 방류시 밀도차로 인한 부력으로 온배수 혼합효과를 높여 온배수에 의한 환경피해 범위를 최소화하기 위해서이다. 특히, 하절기에 저층의 저온 냉각수를 취수할 수 있다는 이점 때문에 향후 계획되는 발전소들도 심층 취 배수 방식을 도입할 것으로 예상된다. 본 연구에서는 원자력 발전소의 냉각시설 중 심층 취 배수 구조물의 입구 주변을 3차원 전산유체역학 코드인 $FLOW-3D^{(R)}$로 모사하여 그 흐름특성을 분석하였다. 취수구(intake)의 경우 연직취수 조건에서 유속 덮개(Velocity cap), 배수구(diffuser)의 경우 방류수의 분사방향에 변화를 주어 모의하였으며, 그 결과 취수구의 경우 유속덮개에 의한 연직 유속성분의 현저한 감소로 인한 어류 유입영향을 최소화할 수 있을 것으로 판단되며, 배수구 희석효과는 Jirka 및 Harleman이 제시한 2차원 온배수 프룸(frume)과 잘 일치 하는 것으로 나타났다.

• 한국유체기계학회 논문집
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• 제19권6호
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• pp.50-54
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• 2016

The performance of a scroll expander is the most important factor for the efficiency of small scale Organic Rankine cycle waste heat power generation systems. In this research, a scroll compressor was purchased and operated in reverse to function as a scroll expander. With air as a working fluid, a series of performance test were conducted on this expander by varying the inlet and outlet pressure. Secondly, We have tested through 2000 to 3500 rpm rotational speed to find the maximum power and efficiency of the expander. And last, It was observed in the initial experiments that the design of the expander's orbiting scroll wrap partially blocked the fluid intake which may have caused unnecessary flow resistance. To verify this theory, a small part of the scroll wrap was removed and the performance test was redone. It was observed that the lower back pressure assure the higher efficiency and power of expander and the rotational speed that shows maximum adiabetic efficiency of scroll expander is 69% at 2500 rpm. And by modified wrap of the scroll, we could get volume flow rate for 13% to 19% and power for 5% to 18% increased. But the maximum efficiency of the modified scroll was decreased 8%.

• 한국음향학회지
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• 제22권2호
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• pp.104-112
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• 2003

유체기계 덕트 내 음원은 흔히 선형 시불변 모델을 이용하여 음원 임피던스와 강도로 특성화되어진다. 그러나 내연기관 및 압축기 음원에 대한 여러 측정에서 물리적으로 타당하지 않은 부의 저항이 보고된 바 있다. 본 논문에서는 유체기계의 시변성이 음원특성에 미치는 영향에 대하여 해석적으로 연구하였다. 이를 위하여 왕복동 피스톤 및 배기계로 구성된 간단한 유체기계를 전형적인 주기적으로 시변하는 계로서 다루었으며 등가음향 회로를 해석하였다. 해석 해를 이용한 모사측정에서는 실제 음원의 시변성이 부의 저항에 대한 주요한 원인임을 볼 수 있다. 비교적 작은 시변항의 크기를 가지는 경우에 피스톤이 정적 계의 고유진동수의 두 배 또는 그 정수로 나뉜 주파수로 작동한다면 음원이 큰 음향 파워를 방사하게 됨을 알 수 있다.

• Asian-Australasian Journal of Animal Sciences
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• 제23권9호
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• pp.1174-1183
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• 2010

In goats fed on dry forage twice a day, an esophageal fistula was used to investigate the physiological factors present in the marked suppression of dry forage intake that occurs after 40 min of feeding. The animals used in this study were five large-type male esophageal- and ruminal-fistulated goats. Roughly crushed alfalfa hay cubes with any large remaining chunks removed were used as feed for this research. The study was conducted under both normal feeding conditions (NFC) and sham feeding conditions (SFC). In the NFC control, the esophageal fistulae were closed by plugs and the animals ate dry forage in the normal manner. In the SFC treatment, before starting the experiment the plugs for closing the esophageal fistula were removed and the cannulae for collecting boluses were fitted into the fistulae. Therefore, the esophageal boluses were removed via an esophageal fistula before they entered the rumen. In the NFC control, eating rates sharply decreased in the first 40 min of feeding and were subsequently maintained at low levels. However, eating rates in the SFC treatment remained high after 40 min of the feeding period had elapsed and the goats ate continuously during the 2 h feeding period. In comparison with the NFC control ($1,794{\pm}203.80\;g$/2 h), cumulative dry forage intake in the SFC treatment ($3,182{\pm}381.69\;g$/2 h) was 77.4% greater (p<0.05) upon conclusion of the 2 h feeding period. In the SFC treatment, cumulative bolus output ($6,804{\pm}469.92\;g$/2 h) was about twofold the cumulative dry forage intake due to cumulative salivary secretion volume ($3,622{\pm}104.13\;g$/2 h) upon conclusion of the 2 h feeding period. The result indicates that large amounts of secreted saliva during dry forage feeding act in conjunction with consumed feed to form the ruminal load responsible for ruminal distension. The increased plasma total protein concentrations were higher in the SFC treatment than in the NFC control. However, plasma and ruminal fluid osmolalities increased in the NFC control during and after feeding but were mostly unchanged in the SFC treatment. In comparison with the NFC control ($3,440{\pm}548.04\;g$/30 min), thirst level in the SFC treatment ($1,360{\pm}467.02\;g$/30 min) was 60.5% significantly less (p<0.05) upon conclusion of the 30 min drinking period. The results of the present study indicate that In the second hour of the 2 h feeding period, dry forage intake is regulated by factors produced when boluses enter the rumen.

• Asian-Australasian Journal of Animal Sciences
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• 제20권9호
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• pp.1367-1373
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• 2007

The aim of this study was to determine the feeding value to sheep of Acacia saligna grown under temperate conditions. Pen trials were undertaken to determine the effects of feeding A. saligna, which had been grown in a Mediterranean environment, on feed intake, nitrogen balance and rumen metabolism in sheep. Sheep were given ad libitum access to A. saligna with or without supplementation with PEG 4,000 or PEG 6,000. PEG 4000 appears to be the major detannification agent used in trials involving high tannin feed despite the fact that PEG 6000 has been shown to be more effective, in vitro. For this reason it was of interest to compare the two, in vivo. Dry matter intake was greater (p<0.05) in sheep supplemented with either PEG 4,000 or PEG 6,000 compared to the control. There was no difference, however, in intake between those supplemented with either PEG 4,000 or 6,000. Although animals were not weighed throughout the trial, a loss in body condition was obvious, in particular in the control group. Intake of N was greater (p<0.05) in sheep supplemented with either PEG 4,000 or PEG 6,000 than in the control. There was no difference in N intake between those supplemented with either PEG 4,000 or PEG 6,000. There were no significant differences in either the faecal or urinary N output between any of the treatment groups and all treatment groups were in negative N balance. Neither the average nor maximum pH of ruminal fluid of the control group was different to those supplemented with PEG. The minimum pH for the control group, however, was significantly higher (p<0.05) than for either of the PEG treatments. The average and the maximum ammonia levels were lower (p<0.05) in the control group compared with those in either of the PEG treatment groups. For all dietary treatments ruminal ammonia levels were well below the threshold for maximal microbial growth. Feeding A. saligna, without PEG, had a definite defaunating effect on the rumen. For all dietary treatments ruminal ammonia levels were well below the threshold for maximal microbial growth. It was concluded that A. saligna was inadequate as the sole source of nutrients for sheep, even with the addition of PEG 4,000 or PEG 6,000. The anti-nutritional effects on the animals were largely attributed to the excessive biological activity of the phenolics in the A. saligna leaves. There is a need to determine other supplements that may be complimentary with PEG to enhance the nutritive value of A. saligna to maintain a minimum of animal maintenance.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2002년도 유체기계 연구개발 발표회 논문집
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• pp.95-101
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• 2002

The head-capacity curves for pumps developed by the pump manufacturer are based on tests of a sin91e pump operating in a semi-infinite pool with no nearby walls or floors and no stray currents. Hence, flow into the pump suction is symmetrical with no vortices or swirling. Pump station designers rely on these curves to define the operating conditions for the pump selected. But various constraints such as size, cost, and limitations on storage time require walls, floors, and pump intakes to be close proximity to each other. From this background, the authors are carrying out a systematic study on the flow characteristics of intakes within a sump found within a sump of pump stations. Model pump intake basin is designed and PIV is adopted as a measuring tool to capture the instantaneous flow patterns. Special attention is paid to investigate the flow patterns near the free surface due to different clearances from back-wall to vertical intake pipe with bell mouse and without. Moreover, the locations and vorticities of the various types of vortices that were found in the examinations are discussed.

• Asian-Australasian Journal of Animal Sciences
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• 제2권2호
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• pp.91-97
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• 1989

The present experiment was carried out to investigate the effects of heat exposure on water metabolism and the passage of indigestible particles in sheep. Water intake, respiratory rate, rectal temperature and pH of ruminal fluid and urine were significantly higher (P<0.05) in the hot environment ($32\;^{\circ}C$) than in the control environment ($20\;^{\circ}C$). Urine osmolality and blood volume were increased, while glomerular filtration rate was decreased, in the hot environment. The liquid flow rate from reticulo-rumen and the excretion of indigestible particles of specific gravity 0.99 (but not 1.27 or 1.38) were increased in the hot environment. From these findings, it is suggested that an increased water intake evoked by heat exposure might affect the flow rate of digesta in sheep.

• Asian-Australasian Journal of Animal Sciences
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• 제12권8호
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• pp.1215-1221
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• 1999

Twelve rumen fistulated cross-bred calves were divided into three groups and fed wheat straw and concentrate mixture according to their maintenance requirement. Animals in group II and III were fed 50 and 100mg rumensin per day, in addition to basal feed. Supplementation of rumensin in the diet decreased the dry matter intake significantly (p<0.05) along with a significant decrease in the straw intake. Digestibility coefficients of all the nutrients were not affected significantly except that of CF digestibility which was lower (p<0.05) in groups II and III as compared to group I. Among N-parameters in the rumen fluid, mean $NH_3-N$ was significantly lower in groups II and III (19.13 and 18.63 mg N/100 ml respectively) than in group I (22.68); total-N and TCA-ppt-N did not differ among the three groups. Total VFA concentration did also not differ among the three groups, however, propionate increased from 24.33 molar % to 32.73 while acetate and butyrate decreased respectively from 65.85 to 58.81% and 9.79 to 8.46%. Total VFA, bacteria and protozoa production rates were not affected significantly due to rumensin in diet. Methane production per kg DDM as well as % of methane in total gas were reduced at both the levels of rumensin on different concentrate ratios with wheat straw as roughage. Similar trend was also observed with rice straw and concentrate mixture as substrate with rumensin addition.