• Title/Summary/Keyword: optimum properties

Search Result 3,682, Processing Time 0.034 seconds

A Study on Flow Properties of Semisolid Dosage Forms

  • Shon, Sung-Gil;Lee, Chi-Ho
    • Archives of Pharmacal Research
    • /
    • v.19 no.3
    • /
    • pp.183-190
    • /
    • 1996
  • There are a wide variety of semi-solid ointments used for healing the skin diseases, whose therapeutic and skin penetration abililties may greatly differ from one another depending on the compositions of ointment vehicles. A computer optimization technique was applied to obtain the optimum formula of o/w type ointment giving the in vitro maximum absorption rate through hairless rat skin membrane. Some of the formulations were selected to find out a relationship between skin penetration of ointment and its Theological characteristics. The experimental value of absorption rate obtained from the ointment by optimum formula agreed well with the theoretical value obtained from a polynomial regression analysis, Three kinds of ointments selected among 15 formulations were obtained with a concentric cylinder type rheometer (Model; Rheolab SM-HM Physica, Germany) at 20, 30, 40 and $50^{\circ}C$ for rheograms of rhelolgical properties of o/w type ointments. As the temperature was raised, all products showed a decrease in both shear stress and yield values. The higher skin penetration, the lower shear stress showed.

  • PDF

Effects of Environmental Factors such as Temperature and Ozone Concentration on the Properties of BR/Crystalline Rubber Blend (BR고무/결정성고무 블렌드의 물성에 미치는 온도 및 오존농도 등의 환경인자의 영향)

  • Park, Chan-Young;Lee, Won-Kee;Min, Seong-Kee
    • Elastomers and Composites
    • /
    • v.45 no.1
    • /
    • pp.44-50
    • /
    • 2010
  • The butadiene rubber(BR) blends with chloroprene rubber(CR) were prepared by mechanical mixing method. Cure characteristics, mechanical properties, ozone resistance properties and dynamic mechanical properties were subsequently examined. The properties of ozone resistance of pure BR was significantly improved through blending with 50 wt% CR. Dynamic characteristics determined from a Rheovibron generally showed two glass transition($T_g$) for the entire blends, $tan{\delta}$ peak monotonically shifted toward the higher temperature with the increasing content of CR. Optimum cure time of compound was significantly lengthened with loading of CR.

Physical and Mechanical Properties of Particleboard made with Powdered Tannin Adhesives (분말상 탄닌수지로 제조한 PB의 물리.기계적 특성)

  • 강석구;이화형
    • Journal of the Korea Furniture Society
    • /
    • v.14 no.2
    • /
    • pp.1-12
    • /
    • 2003
  • This study was carried out to determine the mechanical and physical properties of particle boards glued with condensed tannin (Wattle Tannin) powder that was single-molecule phenolic compounds like powdered phenolic resin. Our findings are; 1) It is necessary to spray water on the chip surfaces for effective application of powdered -form tannin resin. It shows that the best and optimum mat moisture increase is 14% of water spray on the surface of chips for developing PB properties. 2) In general, for both liquid and powdered tannin adhesives, their physical and mechanical properties has been proportional to the increase of resin level. But, the most efficient addition ratio is 16% of resin on dry basis. Specially, it is found that the resin level influences on the amount of free formaldehyde emission. The higher the resin level is, the lower the emission is. These phenomena seem to result from the increase of hexamine or formaline in the adhesives used as a hardener, that reduce the free-formaldehyde amount by reaction of tannin of poly-molecule and water. 3) The optimum condition for manufacturing PBs is the condition of hexamine of 5% and formaline of 6% in mechanical and physical properties. Hexamine is superior to formaline in mechanical and physical properties along with the control of the free formaldehyde emission amount. The result of NaOH's addition is insignificant in all experiments of both mechanical and physical properties.

  • PDF

Applicability of Optimum Algorithm for Automated Design of Electric Railway Pole Foundation (전철주기초 설계 자동화를 위한 최적화 알고리즘의 적용성 검토)

  • Lee, Gi-Yeol;Park, Yong-Dae;Chung, Won-Yong;Song, Kyu-Seok;Lim, Sun-Taek;Kim, Jong-Nam;Lee, Su-Hyung
    • Proceedings of the KSR Conference
    • /
    • 2009.05a
    • /
    • pp.1047-1053
    • /
    • 2009
  • This paper examined an applicability of optimum algorithm to develope an electric railway pole foundation automated design system. Based on the optimization theory that considered subgrade and bearing capacity characteristics, decided an optimum section of electric railway pole foundation. In this research, Optimum algorithm used the feasible direction method in structural analysis and design efficiently. Design variables are considered geometric properties and anchor bolt area of the electric railway pole foundation as optimum construction cost. Constraints are considered settlement., overturning and activity of foundation. And, also composed flexural and shearing strength. According to optimum analysis result., optimization theory is available more economical design comparing with railway pole foundation that is constructed by current standard drawing, and applicability verified in automated design system development.

  • PDF

Determination of the Optimum Flocculant Mixing Ratio for Paper Making Wastewater Treatment (제지 폐수처리를 위한 응집제의 최적 혼합주입량 결정 방법)

  • Cho, Jun-Hyung;Kang, Mee-Ran
    • Journal of Korea Technical Association of The Pulp and Paper Industry
    • /
    • v.40 no.1
    • /
    • pp.41-46
    • /
    • 2008
  • In this study, dewaterability, one of the important properties of wastewater sludge, was investigated using a simple capillary suction time (CST) measurement method. It turned out that one could use the results of CST to find optimum flocculants ratio to improve drainage in wastewater treatment for the printing paper, tissue paper, and newsprint paper mill. Since the optimum ratio of flocculants could be determined with the value of CST, COD removal efficiency could be improved and optimum floc strength could be achieved with precise ratio of flocculants. It was thus that using CST for determining the optimum ratio of flocculants could be economical by reducing the amount of flocculants. Dewaterability could be measured within several seconds using the values of CST in a precise way. The dewaterability could also be useful in investigating the optimum ratio of flocculants.

Study on the Soil Compaction (흙의 다짐에 관한 연구(I))

  • 강문묵
    • Magazine of the Korean Society of Agricultural Engineers
    • /
    • v.11 no.4
    • /
    • pp.1783-1790
    • /
    • 1969
  • It is one of the most economical method of soil stabilization works to compact soil, which increases soil density artificially. Compaction effort is to lessen void of soils, and consequently its aim is to enlarge friction and cohesion force, and reduce permeability of soil. Factors in compaction effort are moisture content, grain size, grain size distribution, physical properties, compaction method and temperature of soils etc. The results obtained in this study on the effects that grain size, gradation and physical properties influence upon compaction effort for 20 samples under the constant compaction method, are summarized as follows: 1. The bigger the maximum dry density is, the smaller the optimum moisture content is, on the other hand, the smaller the maximum dry densityis, the bigger the optimum moisture content is, ingeneral. 2. The coarser the grain size is, the bigger the maximum dry density is, and the optimum moisture content becomes small, and dry density-moisture content curve has the sharp peak, generally. Also, the finer the grain size is the smaller the maximum dry density is, and the optimum moisture content shows the big value, and dry density-moisture content curve has the dull peak. 3. The maximum dry density shows the biggest value on the sample to be about 15% of particles finer than No. 200 sieve. The more the percent passing of No. 10 sieve increase, the smaller the maximum dry density is. Soils which have uniformity coefficient less than 5 in particles larger than 0.074mm hardly show dry density-moisture content curve. 4. There is a relation which is ramax=2.3948-0.0376 Wopt between the maximum dry density and the optimum moisture content, namely, the maximum dry density is increased in proportion to decrease of the optimum moisture content. 5. There are relations to be the straight lines which the maximum dry density decrease, on the other hand, the optimum moisture content increase in accordance with enlargement of Atterberg Limit(LL, PL, PL) in compacted soils.

  • PDF

A Study on Reliability Based Design Optimization For Thin Walled Beam Structures (박판보 구조물의 신뢰성 최적 설계에 관한 연구)

  • Lee, Sun-Byung;Yim, Hong-Jae;Baik, Serl
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
    • /
    • 2001.05a
    • /
    • pp.414-419
    • /
    • 2001
  • In this research, reliability based optimum design is presented for the thin walled beam structures. Deterministic and stochastic optimum design are compared for the thin walled beam structures. Monte Carlo simulation is used for stochastic optimum design with consideration of probabilistic distribution of representative section properties of the thin walled beams with the Response Surface Method.

  • PDF

Studies on the Optimum Preconditioning Condition of BASMA Tobacco Leaves (BASMA 잎담배의 최적 습점조건에 관한 연구)

  • 김기환;김천석
    • Journal of the Korean Society of Tobacco Science
    • /
    • v.11 no.1
    • /
    • pp.79-85
    • /
    • 1989
  • For the Purpose of this study, were researched the optimum condition preconditioning condition of orient tobacco leaves . The loss of 3-methyl pentanoic acid (3-MP) component of BASMA leaves in the treatment process amount to about 60% , but the loss of 3-MP At the optimum conditions of BASMA CTC treatment, the temperature was 45-$65^{\circ}C$ and the treatment time 25-35 minutes. And further, the physical properties of BASMA after CTC treatment was remarkably similar to the control's. Since VTC minimized the loss, it is suggested that CTC method should be changed by VTC method.

  • PDF

Kinetic Properties of Extracted Lactate Dehydrogenase and Creatine Kinase from Mouse Embryonic Stem Cell- and Neonatal-derived Cardiomyocytes

  • Zonouzi, Roseata;Ashtiani, Saeid Kazemi;Hosseinkhani, Saman;Baharvand, Hossein
    • BMB Reports
    • /
    • v.39 no.4
    • /
    • pp.426-431
    • /
    • 2006
  • Embryonic stem cells (ESCs), representing a population of undifferentiated pluripotent cells with both self-renewal and multilineage differentiation characteristics, are capable of spontaneous differentiation into cardiomyocytes. The present study sought to define the kinetic characterization of lactate dehydrogenase (LDH) and creatine kinase (CK) of ESC- and neonatal-derived cardiomyocytes. Spontaneously differentiated cardiomyocytes from embryoid bodies (EBs) derived from mouse ESC line (Royan B1) and neonatal cardiomyocytes were dispersed in a buffer solution. Enzymes were extracted by sonication and centrifugation for kinetic evaluation of LDH and CK with spectrophotometric methods. While a comparison between the kinetic properties of the LDH and CK of both groups revealed not only different Michaelis constants and optimum temperatures for LDH but also different Michaelis constants and optimum pH for CK, the pH profile of LDH and optimum temperature of CK were similar. In defining some kinetic properties of cardiac metabolic enzymes of ESC-derived cardiomyocytes, our results are expected to further facilitate the use of ESCs as an experimental model.

Optimization of Roasting Conditions of Polygonatum sibiricum Roots by a Pressure Roaster (가압볶음장치에서 둥굴레(황정) 근경의 볶음조건 최적화)

  • 권중호;김만배;김동길;이기동
    • Journal of the Korean Society of Food Science and Nutrition
    • /
    • v.27 no.1
    • /
    • pp.80-86
    • /
    • 1998
  • This work was designed to determine the optimum roasting conditions with application of a pressure roaster for improving the roasting process of the Polygonatum sibiricum tea which has been roasting with a traditional method. Soluble solid content of the Polygonatum cibiricum tea was 63.16% in the tea roasted at 0.85kgf/$\textrm{cm}^2$(roasting pressure) and 13.9min(roasting time) which were maximum point by the ridge analysis. The optimum conditions predicted for each corresponding sensory properties of the Polygonatum cibirium tea were 0.87kgf/$\textrm{cm}^2$ and 9.2min in color, 0.89kgf/$\textrm{cm}^2$ and 9.7min in sweet 0.72kgf/$\textrm{cm}^2$ and 5.4min in burnt flavor, 0.89kgf/$\textrm{cm}^2$ and 9.9min in appetizing flavor, 0.87kgf/$\textrm{cm}^2$ and 9.3min in aftertaste, 0.89kgf/$\textrm{cm}^2$ and 10.0min in aroma, and 0.88kgf/$\textrm{cm}^2$ and 9.6min in overall acceptability of the tea. The optimum conditions based on the soluble solid content and sensory properties of the Polygonatum cibiricum tea, were 0.83~0.88kgf/$\textrm{cm}^2$ and 9.7~10.4min.

  • PDF