• Advances in aircraft and spacecraft science
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• 제2권4호
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• pp.445-467
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• 2015

The paper presents some details of the CFD modeling of a novel design where jet ignition devices replace the traditional spark plugs for a faster and more complete combustion. The numerical simulations show how the pre-chamber jet ignition in a Wankel engine differs from reciprocating piston engine applications. The jets issuing from the jet ignition pre-chamber have many different speeds in the different directions as the pressure build-up at the trailing edge of the rotating chamber makes extremely fast the ignition of the chamber mixture in the direction of rotation. Conversely it prevents the jet ignition in the opposite direction. Careful positioning along the periphery and design of the connecting pipes and the prechamber volume with the help of CFD simulations permits to achieve extremely fast and complete combustion as impossible with spark plugs. The paper proposes results of CFD simulations of the combustion evolution within a jet ignited Wankel engine rotor, detailing challenges and opportunities of the application, as well as a first assessment of the impact the faster and more complete combustion permitted by jet ignition may have on the performances of Wankel engines for unmanned aerial vehicles applications.

• Asian-Australasian Journal of Animal Sciences
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• 제5권4호
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• pp.605-610
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• 1992

Two experiments were conducted to investigate into the effects of replacing maize with a mixture of cassava root and leaf meal (CRLM) on the performance of broiler chickens. In experiment 1, CRLM replaced 50 or 100 percent of maize in the control diet. In experiment 2, the 100 percent CRLM based-diet was fortified at a further 3 percent level with coconut oil. A total of 180, one-day old Shaver Starbro chicks, raised up to 49 days of age, were used. There were no significant (p<0.05) differences in final body weights, feed intake and feed efficiency between the control group and the group fed the diet in which 50 percent of the maize was replaced with CRLM. At the 100 percent level of replacement of maize with CRLM, however, final body weights, feed efficiency and carcass yields, were significantly (p<0.05) reduced. Dressing percentage and feed intake were not affected (p>0.05) by level of substitution of maize with CRLM. In experiment 2, when the diet in which all of the maize was replaced with CRLM was fortified with coconut oil at an additional 3 percent level, broiler performance improved and equaled (p=0.05) that obtained on the control maize diet. It was concluded the CRLM can replace 50 percent of maize in broiler diet without adversely affecting performance. However, for the complete replacement of maize with CRLM, it is necessary to further supplement such a diet with a high energy density ingredient if broiler performance is to be maintained.

• 미생물학회지
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• 제11권4호
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• pp.175-180
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• 1973

This study was attempted to see more clear relationships among the enterobacteria, especially between the intestinal normal flora and pathogenic bacteria. It has been known that some intestinal normal flora produce the bactrial metabolites that are harmful to other enteric bacteria. One of the metabolites is known as colicin, the protein fraction, which possesses certain degree of inhibitory effect against other bacterial growth fraction, whih possesses certain degree of inhibitory effect against other bacterial growth. As a preliminary study for a colicin purification, the antagonistic effect of E, coli to groups of Salmonella and Shigella has been studied by means of in vitro quantitative culture method. 1. E.coli showed definite inhibitory effects aganist both Salmonella and Shigella groups in the mixture of two organisms. 2. The inhibitory effects of E.coli in the E.coli-Salmonella and the E.coli-Shigella mixture occurred from 4 hours incubation following the inoculation. 3. Even the complete inhibition of pathogenic enteric bacterial growth was noticed in the E.coli-Salmonella mixture at overnight incubation. 4. Among the diluted mixtures, 1:100, 1:1,000, and 1:10,000, survival rate of pathogenic enteric bacteria in the mixtures with E.coli showed least affected at the 1:1,000 dilution. 5. It was found that the antagonistic effect aganist groups of Salmonella-shigella was depending upon the groups of the genera.

• 한국자동차공학회논문집
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• 제18권6호
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• pp.145-151
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• 2010

The performance of a direct-injection diesel engine often depends on the strength of swirl or squish, the shape of combustion chamber, the number of nozzle holes, etc. This is natural because the combustion in the cylinder was affected by the mixture formation process. Since the available duration to make the mixture formation of air-fuel is very short, it is difficult to make complete mixture. Therefore, an early stage of combustion is violent, which leads to the weakness of noise and vibration. In this paper, the combustion process of a common-rail diesel engine was studied by employing two kinds of pistons. One has several grooves with inclined plane on the piston crown to generate swirl during the compression and expansion strokes in the cylinder in order to improve the atomization of fuel. The other is a toroidal piston, generally used in high speed diesel engines. To take photographs of flame and flaming duration, a four-stroke diesel engine was remodeled into a two-stroke visible single cylinder engine and a high speed video camera was used.

• 한국연소학회지
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• 제20권3호
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• pp.13-20
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• 2015

The performance of a direct-injection diesel engine often depends on the strength of swirl or squish, the shape of combustion chamber, the number of nozzle holes, etc. This is natural because the combustion in the cylinder was affected by the mixture formation process. Since the available duration to make the mixture formation of air-fuel is very short, it is difficult to make complete mixture. Therefore, an early stage of combustion is violent, which leads to the weakness of noise and vibration. In this paper, the combustion process of a common-rail diesel engine was studied by employing two kinds of pistons. One has several cavities on the piston crown to intensify the squish during the compression stroke in order to improve the atomization of fuel, we call this multi cavity piston in this paper. The other is a toroidal single cavity piston, generally used in high speed diesel engines. To take photographs of flame and flaming duration, a four-stroke diesel engine was remodeled into a two-stroke visible single cylinder engine and a high speed video camera was used.

• 설비공학논문집
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• 제3권5호
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• pp.337-349
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• 1991

Heat and mass transfer rates to spray water droplets for spray transients in a high pressure vessel have been predicted by two different droplet models: the complete mixing model and the non-mixing model. In this process, the ambient fluid surrounding the droplets is a real-gas mixture composed of saturated steam and noncondensable hydrogen gas at high pressure. The physical properties of the mixture are estimated by applying the concept of compressibility factor and using appropriate correlations. A computer program, DROPHMT, to calculate the heat and mass transfer rates for two different droplet models has been developed. As an illustrative application of the computer program to engineering practices, heat and mass transfer rates to spray water droplets for spray transients in a Pressurized Water Reactor (PWR) pressurizer have been calculated, and the typical results have been provided.

• 응용통계연구
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• 제23권1호
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• pp.113-121
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• 2010

형사사건에서 STR(short tandem repeat)을 이용한 개인 식별은 범죄현장에서 발견된 유전자 증거와 용의자의 유전자 검사 결과를 이용하여 평가하게 된다. 특히 범죄현장에서 발견된 유전자 증거 표본에 기여자가 두 명 이상인 경우를 Mixture라고 하며, 이는 강간 등과 같은 사건에서 흔히 볼 수 있다. 이러한 상황에서 법의학적 추론을 위해 유전자 증거 표본을 해석하고자 하는 연구들이 계속되어 왔으며, 최근에는 Mixture에서 발생한 대립유전자의 봉우리 면적을 활용하여 유전자 증거를 해석하기 위한 노력들이 계속되고 있다. 따라서 본 연구에서는 봉우리 변적을 이용하여 유전자 증거 표본을 해석하기 위한 연구 방법들에 대해 살펴볼 것이며, 또한 유전자 증거 표본에 기여한 사람의 수가 세 명 이상안 표본으로 확장시킨 연구를 실시해 볼 것이다. 마지막으로 사례틀 통해 유전자 증거를 해석하는 방법을 살펴보고자 한다.

• 한국자동차공학회논문집
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• 제8권2호
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• pp.19-26
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• 2000

This paper presents the effects of initial pressure of mixture on CO, $CO_2$ and NOx emissions in constant volume combustion chamber. The CO, $CO_2,O_2,N_2$ concentrations in the chamber are determined by thermal conductivity detection (Gas-chromatograph) wile the NOx concentration is measured by chemiluminescent detection (NOx Analyser). Methane-air mixture is used as premixed fuel and the measurements are taken with equivalence ratios($\phi$) varing from 0.6 to 1.3, and initial pressures of methane-air mixture varing from 0.1MPa to 0.8MPa in constant volume combustion chamber. The NOx concentration steadily increases with increasing equivalence ratio, peaks in lean flame ($\phi$=0.85~0.9), and then rapidly decreases. However, as the initial pressure of mixture is increased, the equivalence ratio corresponding to the point of peak [NOx] shifts towards leaner conditions. This is caused by a similar shift in the peak [CH], which is caused by the variation with pressure and equivalence ratio of the rate of CH production from $CH_2$ and OH. The maximum combustion pressure peaks at $\phi$ =1.05 and the $CO_2$ concentration peaks at $\phi$=0.95~1.0 while the CO concentration rises sharply at the condition of fuel-rich mixtures. This is caused by complete combustion at $\phi$=0.95.

• Bulletin of the Korean Chemical Society
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• 제9권5호
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• pp.322-324
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• 1988

Selective reduction of aldoximes and ketoximes with lithium borohydride in tetrahydrofuran was investigated. Thus, aldoximes and cyclic ketoximes such as hexanaldoxime, heptanaldoxime, cyclopentanone oxime and cyclohexanone oxime were reduced smoothly to the corresponding N-monosubstituted hydroxylamines at room temperature in 65-93% yield. The reduction of alicyclic ketoxime was very slow, requiring somewhat high reaction temperature ($65^{\circ}C$) for the complete reduction to give the hydroxnylamines. The reduction of aromatic oximes such as benzaldoxime and acetophenone oxime was very sluggish, giving a mixture of the corresponding hydroxylamines and amines at $65^{\circ}C$.

• Journal of Animal Science and Technology
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• 제52권3호
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• pp.229-236
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• 2010

Effect of molasses addition to complete calf starter (CCS) and the following pellet processing was evaluated with 12 Holstein-Friesian (HF) calves (7-14 d old with $42\;{\pm}\;5.5\;kg$ average BW), with 6 calves (replicate) per treatment. The CCS was formulated with 65% concentrate calf starter and 35% local corn fodder. On the CCS, molasses was added either 5% (M5) or 10% (M10), then the mixture was pelleted and fed to the calves for 7 weeks. Molasses addition, regardless of addition level, improved (p<0.05) both the durability and hardness of the pellet which contains 35% of high fibrous local corn fodder. Upon feeding to calves, the feed intake and daily gain were numerically higher with 5% molasses addition compared to 10% molasses addition. Blood VFA level was remarkably higher (p<0.01) in calves fed M10 than calves fed M5. There was no difference (p>0.05) in blood glucose level between M5 and M10. Length and number of papillae were not different (p>0.05) by the addition levels of molasses. However, there was one exception in number of papillae at caudo-dorsal sac which were higher (p<0.05) number in M5 than M10 calves. Considering the quality of CCS pellet, calf performance and rumen development, there was no additional benefit of 10% molasses addition compared to 5%. From the results of this study, 5% molasses addition could be recommended for local farmer when they utilize local corn fodder to make CCS for HF calves in Indonesia.