• 한국가시화정보학회지
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• 제18권3호
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• pp.77-83
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• 2020

A uniflow cyclone has simple structure with a single channel in one direction. The one directional particle removal enables the uniflow cyclone to have compact size and low pressure drop. However, it has low collection efficiency compared to conventional cyclones. In this study, the effect of primary geometry on the performance of a uniflow cyclone with swirl vane is numerically investigated for the design of high performance uniflow cyclone. It is found that as the vortex finder diameter is increased, the pressure drop and the collection efficiency are decreased. Also, the same trend is predicted when the vortex finder height is increased. The best collection efficiency is predicted to be obtained when the vortex finder height is equal to the diameter of a cyclone. Reducing the body height by half will increase the pressure drop by 41%. When the body height is decreased, the collection efficiency is first increased and then decreased. The best collection efficiency is obtained when the body height is 4~5 times the cyclone diameter. Overall, the particle collection efficiency is highest when the Dν/D is equal to 0.3. But, the pressure drop is as high as 1592 Pa. Considering both collection efficiency and pressure drop, the best design is when Dν/D, Hν/D, and Hb/D are equal to 0.5, 1, and 5, respectively.

• The Journal of Asian Finance, Economics and Business
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• 제8권3호
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• pp.763-769
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• 2021

The relationship between government size and unemployment is an important topic of study in economics. Large public expenditure has been blamed for causing higher unemployment contrary to the belief that it would help in reducing unemployment. More research on the topic, however, needs to be done as the available literature has been based largely on data from developed countries. The present paper examines the existence of the relationship in states of India by using panel data analysis. For more comprehensive study, public expenditure is divided into development, non-development, and aggregate expenditures, while the types of unemployment under consideration are usual status and current weekly status. Indeed, it has been observed that development and non-development expenditures increase both the types of unemployment though the impact of the latter is higher. The findings are important as it implies that a cut in expenditure can be an important fiscal tool to fight unemployment. It was further observed that unemployment was higher among states with a more educated population, which also suggests a revisiting of the education policy in the country. States ruled by left parties have higher unemployment rate. Higher income states as well as states with higher growth rate tend to have lower unemployment rate.

• 한국시뮬레이션학회논문지
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• 제18권3호
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• pp.91-102
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• 2009

평균 윈도우 크기는 평균 처리율과 많은 관계를 가지고 있다. 제안된 dropper는 fairness를 향상시키기 위해 윈도우 크기를 각 플로우의 레벨에 맞게 제어하도록 한다. 경쟁 패킷 드랍은 플로우가 많은 양의 대역폭을 차지하기 위해 동작한다. 경쟁 패킷 드랍 때문에 플로우는 전송 속도를 반으로 줄이게 되며, 이에 따라 코어 링크의 여유 용량이 존재하게 된다. 다른 플로우는 이 새로운 용량을 사용하게 되고, 따라서 다른 플로우는 좋은 처리율을 가지게 된다. 이런 방식으로 TCP의 전송속도를 제어하는 edge router의 새로운 기능 block인 TRC Dropper(Transmission Rate Control Dropper)를 제안한다. 제안한 TRC Dropper를 통하여 플로우들 간에 공평한 대역폭 분배를 실현하여 상대적으로 차별화된 서비스를 제공할 수 있다.

• Elastomers and Composites
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• 제58권3호
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• pp.103-111
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• 2023

The abrasion resistances of silica-filled styrene-butadiene rubber (SBR) compounds prepared with and without dicyclopentadiene resin (SBR-R and SBR-0, respectively) were studied using four different abrasion testers, namely cut and chip (CC), Lambourn, DIN, and laboratory abrasion tester (LAT100). The effect of the resin on the abrasion behavior was elucidated by analyzing the morphologies and size distributions of wear particles. All the wear particles had rough surfaces, but those obtained in the Lambourn abrasion test exhibited relatively smooth surfaces. The size distributions of the wear particles showed different trends depending on the abrasion tester and the rubber compound; however, most of the wear particles were larger than 1000 ㎛. The SBR-R sample showed a wide range of particle sizes (from 63 ㎛) in the LAT100 abrasion test and majority of the wear particles were 500-1000 ㎛, whereas the SBR-0 sample had the most distribution of larger than 1000 ㎛. The abrasion rates of SBR-0 sample were lower than those of the SBR-R sample for the CC and LAT100 abrasion tests, but the Lambourn abrasion test result showed the opposite trend. Addition of the resin influenced the abrasion behavior, however the effect varied depending on the type of abrasion tests.

• Asian-Australasian Journal of Animal Sciences
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• 제22권12호
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• pp.1620-1624
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• 2009

This study aimed to clarify the effect of mobile bag size and ratio of sample size to bag surface area on intestinal digestibility of forage in sheep. Four Suffolk ewes fitted with ruminal and proximal duodenal cannulae were fed second-cut Italian ryegrass (Lolium multiflorum Lam.) hay twice daily, and the same forage was used to measure intestinal digestibility. The forage samples were incubated in the rumen for 16 h and then in pepsin-HCl solution for 3 h before intestinal incubation. The incubated forage samples were placed in a nylon mobile bag. The bag sizes used were either 20 mm${\times}$20 mm (small bag size; SBS) or 30 mm${\times}$30 mm (large bag size; LBS) and the ratio of the sample size to the surface area of the bag was either 5.5 $mg/cm^{2}$ (low ratio; LR) or 11.0 $mg/cm^{2}$ (high ratio; HR) resulting in four different treatment conditions: SBS-LR, SBS-HR, LBS-LR and LBS-HR. Eight bags per animal were inserted through the duodenal cannulae at 15-min intervals and were subsequently collected from the feces of the animal. The mean intestinal bag transition time did not differ significantly between animals, but ranged from 23.2 to 27.0 h. The intestinal digestibility of dry matter (IDDM) ranged from 0.162${\pm}$0.019 g/g in the SBS-HR treatment group to 0.195${\pm}$0.018 g/g in the SBS-LR treatment. The intestinal digestibility of crude protein (IDCP) ranged from 0.610${\pm}$0.031 g/g in the LBS-LR treatment to 0.693${\pm}$0.018 g/g in the SBS-LR treatment. There was no difference in the IDDM and IDCP between different treatments. It was therefore concluded that the size of the mobile bag and the ratio of the sample size to the bag surface area did not influence the intestinal digestibility of forage. Future studies should use bags with high ratios of sample size to surface area in order to obtain sufficient residue for further analysis.

• Asian-Australasian Journal of Animal Sciences
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• 제31권1호
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• pp.98-105
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• 2018

Objective: This study aimed to assess the effect of pelleted and expanded sorghum-based feeds prepared with different moisture levels and particle size of ingredients on metabolizable energy, ileal digestibility of amino acids and broiler performance. Methods: The experiment was performed with 720 male broiler chicks of the Cobb strain, with treatments of six replications, with 15 birds each; they were arranged in a completely randomized design and $2{\times}2{\times}2$ factorial scheme (pelleted or expanded feed processing, 0.8% or 1.6% moisture addition in the mixer, and particle size of 650 or 850 microns). Results: Higher pellet quality (pellets, % and pellet durability index [PDI]) was obtained in expanded diets and inclusion of 1.6% moisture. The particle size of 850 microns increased the PDI of final diet. All studied treatments had no significant effect on weight gain and broiler carcass and cut yields. Lower feed conversion occurred for birds fed pelleted feed at 42 d. The highest apparent metabolizable energy (AME) and apparent metabolizable energy corrected to zero nitrogen balance (AMEn) values of feed in the initial rearing phase (10 to 13 days) were observed in birds fed pelleted feed or for feed prepared with 1.6% moisture. The highest ileal digestibility coefficients of amino acids were obtained with the consumption of pelleted feed prepared with a particle size of 650 microns and 1.6% moisture. Conclusion: Pelleted feed prepared with a milling particle size of 650 microns and 1.6% moisture provided increased ileal digestibility of amino acids and AMEn in the starter period. However, the expanded feed improved pellet quality and feed conversion of broilers at 42 days of age. We conclude that factors such as moisture, particle size and processing affect the pellet quality, and therefore should be considered when attempting to optimize broiler performance.

• 한국품질경영학회:학술대회논문집
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• 한국품질경영학회 1998년도 The 12th Asia Quality Management Symposium* Total Quality Management for Restoring Competitiveness
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• pp.680-695
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• 1998

The objective of this study is to optimize the responses of the creep feed ceramic grinding process simultaneously by an off-1ine multicriteria optimization methodology. The responses considered as objectives are material removal rate, flexural strength, normal grinding force, workpiece surface roughness and grinder power. Alumina material was ground by the creep feed grinding mode using superabrasive grinding wheels. The process variables optimized for the above objectives include grinding wheel specification, such as bond type, mesh size, and grit concentration, and grinding process parameters, such as depth of cut and feed rate. A weighting method transforms the multi-objective problem into a single-objective programming format and then, by parametric variation of weights, the set of non-dominated optimum solutions are obtained. Finally, the multi-objective optimization methodology was tested by a sensitivity analysis to check the stability of the model.

• ETRI Journal
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• 제35권3호
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• pp.538-541
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• 2013

A compact microstrip lowpass filter (LPF) with an elliptic function response is proposed. A high equivalent capacitance and inductance between the structures of the resonator result in the sharp transition band of 0.04 GHz from 4 GHz to 4.04 GHz with an attenuation level of -3 dB and -20 dB, respectively. To improve the LPF rejection band, multiple open stubs are connected to the proposed resonator. A filter with a 3-dB cut-off frequency at 4 GHz is designed, fabricated, and measured, and agreement between the measured and simulated results is achieved. The results show that a stopband bandwidth of 131% with a suppression level better than -20 dB is obtained while achieving a compact size with a wide stopband.

• Korean Chemical Engineering Research
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• 제52권6호
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• pp.775-780
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• 2014

Micellar enhanced ultrafiltration (MEUF) was used to remove cadmium from an aqueous solution using sodium dodecyl sulfate (SDS) as a surfactant. Operational parameters such as initial permeate flux, retentate pressure, initial cadmium concentration, pH solution, molecular weight cut-off (MWCO), and molar ratio of cadmium to SDS were investigated. Removal efficiency of cadmium from an aqueous solution increased with an increase of retentate pressure, pH solution and molar ratio of cadmium to SDS, and decreased with an increase of initial permeate flux. Higher removal efficiency of cadmium from the aqueous solution was achieved using lower MWCO (smaller membrane pore size). Under optimized experimental condition, cadmium removal efficiency reached 74.6 % within an hour. Using MEUF-ACF hybrid process the removal efficiency of both cadmium and SDS was found to be over 90%.

• Transactions on Electrical and Electronic Materials
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• 제10권4호
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• pp.107-110
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• 2009

In this study, the Hall effect has been studied in n-GaAs samples characterized by V/IIl growth ratios of 25, 50 and 100 and prepared by metal organic chemical vapor deposition. For the Hall effect measurements, the grown samples were cut to a size of 1${\times}$1 cm. The measurements were carried out at room temperature, using Indium contact metal at the four corners of the samples. According to the experimental results, the Schottky effect was not ovservation. Also for the n-GaAs sample of V/Ill 100 ratio the electron drift velocity was very high.