• Title/Summary/Keyword: Combination ratio

Search Result 1,610, Processing Time 0.024 seconds

Effects of Temperature and Salinity on Germination and Vegeative Growth of Enteromorpha multiramosa Bliding(Chlorophyceae, Ulvales) (해산 녹조 털가지파래(Enteromorpha multiramosa Bliding)의 발아와 생장에 대한 온도와 염분도의 효과)

  • 김광용
    • Journal of Plant Biology
    • /
    • v.33 no.2
    • /
    • pp.141-146
    • /
    • 1990
  • Germination and vegetative growth of Enteromorpha multiramosa Bliding from Pyoson, Cheju Island were investigated in laboratory under various combinations of temperature (5-$25^{\circ}C$) and salinity (8-48$^{\circ}C$). Percent level of germination was relatively high at all combinations of the two factors. The highest value among the combinations was revealed at 15$^{\circ}C$ and 32$\textperthousand$. Dry weight also was fairly high at all levels of combination with maximum value at 2$0^{\circ}C$ and 32$\textperthousand$. Analysis of variance for germination and growth was completed respectively and polynomial prediction models were constructed. F ratio revealed that all factors had a significant effect (p<0.001) on percentage of germination and dry weight, and their interactions also were significant (p<0.001), although the F ratio of interactions was far less than that for either the separate effect of temperature or salinity. Response surface of polynomial equation represented that temperature influenced less than salinity on germination, while it effected remarkably on vegetative growth, so the Enteromorpha multiramosa was kept to visible macrothalli from winter to spring in Cheju Island.

  • PDF

Axial Behavior of High Performance Fiber Reinforced Cementitious Composite Columns with PVA Fibers (PVA섬유를 사용한 고인성 시멘트 복합체 기둥의 압축거동)

  • Byun Jang-Bae;Jeon Su-Man;Jeon Esther;Kim Sun-Woo;Hwang Sun-Kyung;Yun Hyun-Do;Lim Byung-Hun
    • Proceedings of the Korea Concrete Institute Conference
    • /
    • 2005.11a
    • /
    • pp.29-32
    • /
    • 2005
  • An experimental investigation on the strength and behavior of High Performance Fiber Reinforced Cement Composite(HPFRCC) column with Polyvinyl alcohol(PVA) fibers under axial load have been carried out. The columns were subjected to monotonic axial compression until failure. The variables in this study are the combination ratio of PVA, and the volumetric ratio of transverse reinforcement. Test results showed that the fibers, when used in PVA2.0, could result in superior composite performance compared to their individual fiber reinforced cement composites.

  • PDF

Design Optimization of a Staggered Dimpled Channel Using Neural Network Techniques (신경회로망기법을 사용한 엇갈린 딤플 유로의 최적설계)

  • Shin, Dong-Yoon;Kim, Kwang-Yong
    • The KSFM Journal of Fluid Machinery
    • /
    • v.10 no.3 s.42
    • /
    • pp.39-46
    • /
    • 2007
  • This study presents a numerical procedure to optimize the shape of staggered dimple surface to enhance turbulent heat transfer in a rectangular channel. The RBNN method is used as an optimization technique with Reynolds-averaged Navier-Stokes analysis of fluid flow and heat transfer with shear stress transport (SST) turbulence model. The dimple depth-to-dimple print diameter (d/D), channel height-to-dimple print diameter ratio (H/D), and dimple print diameter-to-pitch ratio (D/S) are chosen as design variables. The objective function is defined as a linear combination of heat transfer related term and friction loss related term with a weighting factor. Latin Hypercube Sampling (LHS) is used to determine the training points as a mean of the design of experiment. The optimum shape shows remarkable performance in comparison with a reference shape.

An Experimental Study on NOx Characteristics in Air-Staging Burner (공기-다단 연소기에서의 NOx 발생특성)

  • Sung, Yong-Jin;Cho, Eun-Seong;Chung, Suk-Ho
    • Proceedings of the KSME Conference
    • /
    • 2001.11b
    • /
    • pp.167-171
    • /
    • 2001
  • Air-staging combustion is a relatively well-known technique to reduce NOx emission and used in combination with other techniques nowadays. However, the design variables are still selected depending upon operating circumstances. Though the fuel-rich condition of the primary combustion zone is very helpful to NOx reduction, its range is known to be restricted by the increase of carbon monoxide. However, in many cases carbon monoxide level is so low not to be the restriction at all. So we tried to expand the equivalence ratio range to the richer condition in the primary combustion zone and make the function of each burner component and its contribution to the overall NOx production clear.

  • PDF

Engineering properties of expansive clayey soil stabilized with lime and perlite

  • Calik, Umit;Sadoglu, Erol
    • Geomechanics and Engineering
    • /
    • v.6 no.4
    • /
    • pp.403-418
    • /
    • 2014
  • There are around 6700 millions tons of perlite reserves in the world. Although perlite possesses pozzolanic properties, it has not been so far used in soil stabilization. In this study, stabilization with perlite and lime of an expansive clayey soil containing smectite group clay minerals such as montmorillonite and nontronite was investigated experimentally. For this purpose, test mixtures were prepared with 8% of lime (optimum lime ratio of the soil) and without lime by adding 0%, 10%, 20%, 30%, 40% and 50% of perlite. Geotechnical properties such as compaction, Atterberg limits, swelling, unconfined compressive strength of the mixtures and changes of these properties depending on perlite ratio and time were determined. The test results show that stabilization of the soil with combination of perlite and lime improves the geotechnical properties better than those of perlite or lime alone. This experimental study unveils that the mixture containing 30% perlite and 8% lime is the optimum solution in stabilization of the soil with respect to strength.

Transdermal Delivery of Diclofenac Using Microemulsions

  • Kweon, Jang-Hoon;Chi, Sang-Cheol;Park, Eun-Seok
    • Archives of Pharmacal Research
    • /
    • v.27 no.3
    • /
    • pp.351-356
    • /
    • 2004
  • A transdermal preparation containing diclofenac diethylammonium (DDA) was developed using an O/W microemulsion system. Of the oils tested, lauryl alcohol was chosen as the oil phase of the microemulsion, as it showed a good solubilizing capacity and excellent skin permeation rate of the drug. Pseudoternary phase diagrams were constructed to obtain the concentration range of oil, surfactant and cosurfactant for microemulsion formation, and the effect of these additives on skin permeation of DDA was evaluated with excised rat skins. The optimum formulation of the microemulsion consisted of 1.16% of DDA, 5% of lauryl alcohol, 60% of water in combination with the 34.54% of Labrasol (surfactant)/ethanol (cosurfactant) (1:2). The efficiency of formulation in the percutaneous absorption of DDA was dependent upon the contents of water and lauryl alcohol as well as Labrasol: ethanol mixing ratio. It was concluded that the percutaneous absorption of DDA from microemulsions was enhanced with increasing the lauryl alcohol and water contents, and with decreasing the Labrasol:ethanol mixing ratio in the formulation.

유한요소법을 이용한 전방압출공정의 내부결함에 관한 연구

  • 김태형;김병민;강범수;최재한
    • Proceedings of the Korean Society of Precision Engineering Conference
    • /
    • 1992.04a
    • /
    • pp.79-83
    • /
    • 1992
  • According to the variation of hydrostatic pressure on the central axis of deformable material, the V-shaped central bursting defect may be created on extrusion or drawing processes. The process factors whichaffect the generation of defects are die semi-angle, reduction ratio of cross-sectional area, friction factor, material properties and so on. The combination of these factors can determine the prossibility of defect creation and the shape of various round holes which have been created inside already. By the rigid plastic finite element method, this paper describes the observations of change in shape of a round hole with process conditions suchas die semi-angle, reduction ratio of cross-sectional area and friction factorat the unsteady state of axi-symmetrical extrusion process when the round hole is alreadyexisted inside the original billet, and also, the effects of process factors are investigated to prevent the possible defects.

Light-susceptibility of Camptothecin Production from in Vitro Cultures of Camptotheca acuminata Decne

  • Park, Young-Goo;Park, Mee-Hee;Yang, Jae-Kyung;Chung, Young-Gwan;Park, Myung-Suk
    • Biotechnology and Bioprocess Engineering:BBE
    • /
    • v.8 no.1
    • /
    • pp.32-36
    • /
    • 2003
  • Production of camptothecin ((PT) from callus cultures of Camptotheca acuminata Decne was affected by light and culture conditions. Among the culture media tested, modified B5 medium containing 3% (w/v) sucrose, 2 mg/L B,4-D, 2 times of MS medium vitamins, 500 mg/L casein hydrolysate, 250 mg/L myo-inositol, 0.05% (w/v) activated charcoal, and 0.15% (w/v) gelite was used for callus induction . The highest cell growth and CPT production were obtained in dark and green light condition, respectively. Photoperiod has no effect on cell growth and CPT production. Both cell growth and CPT production were also influenced by combination ratio of red and blue light .Cell growth and CPT production were the highest in the ratio of red and blue light,90:10.

In-Cylinder Air Flow Characteristics of the HCCI Engine along with Variable Intake Ports (HCCI 엔진의 흡기포트 입구부 변화에 따른 유동특성 비교)

  • Kim, Min-Jung;Lee, Sang-Kyoo;Rhim, Dong-Ryul;Chung, Jae-Woo;Kang, Woo
    • 한국전산유체공학회:학술대회논문집
    • /
    • 2008.03b
    • /
    • pp.272-275
    • /
    • 2008
  • One of the important operating factors for the air-fuel pre-mixed conditions in an HCCI engine is an in-cylinder flow. In this study, unsteady in-cylinder air flow characteristics in a diesel engine as a reference engine of an HCCI engine development were numerically analysed. Unsteady flow analyses were conducted with the combination of 3 intake port inlets, then the in-cylinder air flow distribution and swirl ratio results from a case were compared with the results from the other cases.

  • PDF

A Case-Control Study on the Relationship of Fiber Intake and Hemorrhoids (섬유질 섭취와 치질의 상관성에 관한 환자-대조군 연구)

  • 이상선
    • Journal of Nutrition and Health
    • /
    • v.27 no.1
    • /
    • pp.71-78
    • /
    • 1994
  • Recently the incidence of hemorrhoids has been increased. There were various factors related to hemorrhoids, the amount of fiber intake was known as one of them. And so we performed this case-control study to investigate the association of hemorrhoids and fiber intake. The data was obtained by the combination of self-administered questionnaire and personal interview. The study population was consisted of matched 156 pairs, the cases were selected from S-hospital in Seoul, the age and sex matched control from the general population. The statistical analysis was performed by matched-analysis. The results summarized as follow : 1) As socio-economic status were low, the odds ratio of hemorrhoids were high. 2) There was significant association between hemorrhoids and regularity of eating time rather than regularity of defecation. 3) The odds ratio of hemorrhoids was 3 times higher in the presence of constipation. 4) The incidence of hemorrhoids was influenced by psychological characteristics such as somatization, obsessive-compulsive, depression, and anxiety. 5) Fiber intake was significantly lower in the cases compared to the controls. When the constipation was controlled, the fiber intake was still lower in the cases. These data provide additional evidence that the fiber intake was related to hemorrhoids.

  • PDF