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A MODIFIED SOLUTION PROCEDURE FOR THE ELLIPTIC-TYPE CONDITIONAL MOMENT CLOSURE MODEL IN NONPREMIXED TURBULENT REACTING FLOW

  • Liu, Tao;Huh, Kang-Yul
    • 한국연소학회:학술대회논문집
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    • 1997.06a
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    • pp.113-122
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    • 1997
  • The conditional moment closure formulation considering the molecular and turbulent diffusion is derived. A simplified solution procedure is proposed to reduce the computational burden due to the increased dimensionality of the conditionally averaged variables. A conditionally averaged variable is expressed as a linear weighted average of the two extremes, 'no reaction' and 'equilibrium' states. The modified elliptic-type conditional moment closure formulation is implemented to simulate a two dimensional nonpremixed mixing layer reacting flow. Results show good agreement for the conditional averages of the species concentration in Bilger et al.

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Large displacement geometrically nonlinear finite element analysis of 3D Timoshenko fiber beam element

  • Hu, Zhengzhou;Wu, Minger
    • Structural Engineering and Mechanics
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    • v.51 no.4
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    • pp.601-625
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    • 2014
  • Based on continuum mechanics and the principle of virtual displacements, incremental total Lagrangian formulation (T.L.) and incremental updated Lagrangian formulation (U.L.) were presented. Both T.L. and U.L. considered the large displacement stiffness matrix, which was modified to be symmetrical matrix. According to the incremental updated Lagrangian formulation, small strain, large displacement, finite rotation of three dimensional Timoshenko fiber beam element tangent stiffness matrix was developed. Considering large displacement and finite rotation, a new type of tangent stiffness matrix of the beam element was developed. According to the basic assumption of plane section, the displacement field of an arbitrary fiber was presented in terms of nodal displacement of centroid of cross-area. In addition, shear deformation effect was taken account. Furthermore, a nonlinear finite element method program has been developed and several examples were tested to demonstrate the accuracy and generality of the three dimensional beam element.

Analysis of Collision-induced Derailments of a Wheel-set Model Using MBD and FEM Simulation (MBD와 FEM을 이용한 단일윤축 모델의 충돌 후 탈선거동의 해석)

  • Lee, Jun-Ho;Koo, Jeong-Seo
    • Proceedings of the KSR Conference
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    • 2011.10a
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    • pp.1868-1873
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    • 2011
  • In this paper, a theoretical formulation of a simplified wheel-set model for collision-induced derailments was evaluated by numerical simulations for the wheel-climb derailment and wheel-lift derailment types. The derailment types were classified into the wheel-climb derailment and the wheel-lift derailment according to the friction force direction of the wheel-flange. The wheel-climb derailment type was classified into Climb-up, Climb/Roll-over, and Roll-over-C, and wheel-lift derailment type was classified into Slip-up, Slip/Roll-over and Roll-over-L. To verify the theoretical equations derived for the wheel-climb derailment and the wheel-lift derailment, dynamic simulations using RecurDyn of Functionbay and Ls-Dyna of LSTC were performed and compared for some examples. The derailment predictions of the suggested theoretical formulation were in good agreement with those of the numerical simulations. The direction of the frictional force between the wheel-flange and the rail can be well predicted using the suggested derailment formulation at a initial derailment.

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Formulation of sustained-release matrix tablets of nifedipine (니페디핀 서방성 정제의 제제설계)

  • Cui, Yu;Kim, Seung-Su;Park, Eun-Seok;Chi, Sang-Cheol
    • Journal of Pharmaceutical Investigation
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    • v.32 no.2
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    • pp.95-101
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    • 2002
  • Matrix tablets of nifedipine (NP) were prepared with Eudragit, diluent (lactose or Ca. phosphate) and Mg. stearate employing two different preparation methods (wet granulation and direct compression) to develop its sustained-release dosage forms. The effects of various formulation factors on the dissolution rate of the drug were investigated. Dissolution test was studied in pH 6.8 phosphate buffer containing 1% sodium lauryl sulfate using the paddle method. Formulation factors were the type and content of Eudragit, the type of diluent and the tablet preparation method. The optimum formula of NP matrix tablet, which resulted in a similar dissolution profile to that from Adalat Oros used as a reference, was 30 mg NP, 10% Eudragit RS, 2% Mg. stearate and an adequate quantity of lactose to yield 500 mg weight using the wet granulation method.

The Clinical Study on the Effect of the Sulguanjul-bang No.1 According to Formulation (퇴행성 슬관절염 환자에 대한 슬관절방(膝關節方) 1호(號)의 제형변화 유효성 임상연구)

  • Park, Min-Jung;Seo, Jin-Woo;Sung, In-Hyung;Kim, Nam-Ok;Sung, Su-Min;Chung, Ae-Kyung;Shin, Dae-Hee;Park, Koae-Hwan
    • Herbal Formula Science
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    • v.13 no.2
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    • pp.193-206
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    • 2005
  • Objective: This study is designed to compare the effects of Sulguanjul-Bang No.1 on osteoarthritis in knee joint according to formulation. Methods: 47 patients with symptomatic osteoarthritis of the knee joint were enrolled in a open clinical trial. The 47 patients were devided into two groups at random and taken Sulguanjul-bang No.1 with decoction type, suspension type respectively for8 weeks. After 8-week treatment period, the following parameters were analyzed ; Visual analogue Scale(VAS), Lysholm index score, patients' global assessment. Results: Sulguanjul-bang No.1 treatment led to significant improvement in the pain and symptoms of osteoarthritis as determined by all efficacy measures. After 8 weeks of therapy, there was significant improvement in VAS, Lysholm index and patients' global assessment. But there is no significant difference between two groups. Conclusions: Sulguanjul-bang No.1 was very beneficial pain relief effect and functional improvement irrespect of formulation, decoction type or suspension type.

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A coupled Ritz-finite element method for free vibration of rectangular thin and thick plates with general boundary conditions

  • Eftekhari, Seyyed A.
    • Steel and Composite Structures
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    • v.28 no.6
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    • pp.655-670
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    • 2018
  • A coupled method, that combines the Ritz method and the finite element (FE) method, is proposed to solve the vibration problem of rectangular thin and thick plates with general boundary conditions. The eigenvalue partial differential equation(s) of the plate is (are) first reduced to a set of eigenvalue ordinary differential equations by the application of the Ritz method. The resulting eigenvalue differential equations are then reduced to an eigenvalue algebraic equation system using the finite element method. The natural boundary conditions of the plate problem including the free edge and free corner boundary conditions are also implemented in a simple and accurate manner. Various boundary conditions including simply supported, clamped and free boundary conditions are considered. Comparisons with existing numerical and analytical solutions show that the proposed mixed method can produce highly accurate results for the problems considered using a small number of Ritz terms and finite elements. The proposed mixed Ritz-FE formulation is also compared with the mixed FE-Ritz formulation which has been recently proposed by the present author and his co-author. It is found that the proposed mixed Ritz-FE formulation is more efficient than the mixed FE-Ritz formulation for free vibration analysis of rectangular plates with Levy-type boundary conditions.

Analytical Approach for Optimal Allocation of Distributed Generators to Minimize Losses

  • Kaur, Navdeep;Jain, Sanjay Kumar
    • Journal of Electrical Engineering and Technology
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    • v.11 no.6
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    • pp.1582-1589
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    • 2016
  • In this paper the integration of Distributed Generation (DG) in radial distribution system is investigated by computing the optimal site and size of DG to be placed. An analytical expression based on equivalent current injection has been derived by utilizing topological structure of radial distribution system to find optimal size of DG to minimize losses. In the presented formulation, the optimal DG placement is obtained without repeatedly computing the load flow. The proposed formulation can be used to find the optimal size of all types of DGs namely Type-I, Type-II, Type-III and Type-IV DGs. The investigations are carried out on IEEE 33-bus and 69-bus radial distribution systems. The optimal DG placement results into reduction in active and reactive power losses and improvement in voltage profile of the buses.

Immediate Drug Release Enhancement of Nateglinide Using Fumaric Acid (푸마르산을 이용한 나테글리니드 함유 속방출형 제형의 약물방출 개선에 관한 연구)

  • Lee, Sung-Hoon
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.18 no.1
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    • pp.506-512
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    • 2017
  • The purpose of this study was to improve release rate and bioavailability of nateglinide formulation. Polymorphism selection and particle size control were performed to enhance formulation dissolution rate, and a pH modifier was included in the formulation to overcome pH-dependent solubility of nateglinide. The enhanced dissolution rate was characterized by using a dissolution test. The results showed that H-type raw material had a higher dissolution rate than that of B-type raw material. There was 6.2% difference in dissolution between the two materials at 60 min. With regard to particle size, raw material with a $1.13{\mu}m$ particle size showed a 20% faster release rate than that of raw material with a $2.28{\mu}m$ particle size. Furthermore, fumaric acid was included in formulation as a pH modifier. That addition produced a greater than 50% improvement in dissolution rate. In conclusion, dissolution rate of nateglinide can be enhanced by optimizing its polymorphism and particle size; moreover, a synergistic effect on the enhancement of dissolution rate is obtained by including fumaric acid, a pH modifier, in the formulation.

A Study on The Manufacturing Method, Formulation and Toxicity for Clinical Use of Topical Agents in Geumgweyoryak (《금궤요략(金匱要略)》 외용제의 임상활용을 위한 제법, 제형 및 독성에 대한 고찰)

  • You, Jae-Hyun;Kim, Kyuseok
    • The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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    • v.35 no.1
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    • pp.24-37
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    • 2022
  • Objectives : The purpose of this literature review is to analyze process of manufacture and formulation and toxicity of Geumgweyoryak(金匱要略)'s external applicants for modern and safe using. Methods : This study used the Geumgweyoryak(金匱要略) reprinted by Zhao Kaimei(趙開美) as basic data for a understanding of the manufacture and formulation and toxicity for external applicants. Among the 25 chapters, the 22 chapters were studied except for the last three chapters, which are known to be written by later writers. Based on the above, Geumgweyoryeok(金匱要略)'s external applicants was analyzed the process of manufacture, formulation and the toxicity. Results : There are 11 types of external applicants of Geumgweyoryak(金匱要略). Washing method(洗法) was used 2 times, Drop method(瀝法) was used 1 time, Smoke method(熏法) was used 2 times, Rubbing method(摩法) was used 1 time, Plaster method(敷法) was used 2 times, Invading method(浸法) was used 1 time, Suppository method (坐法) was used 2 times, Flatiron method(烙法) was used 1 time. According to classified the modern formulation, there are 4 types of powder formulation, 4 types of liquid formulation, 2 types of suppository, and 1 type of Semi-solid formulation. Especially toxic drugs, such as Realgar(雄黃) or Hydrocerussite(鉛粉), should be careful. When Realgar(雄黃) smokes, a toxic substance called AS2O3 can come out. Hydrocerussite(鉛粉) can cause lead poisoning. Lead increases the risk of anemia, dehydration, and lead neuropathy when chronically exposed. Conclusion : We supposed that this study can serve as a basic data to help clinical Korean doctors to use the prescription for external applicants more safely and to easily apply it in the form of external applicants.

Development of Formulation of Ten-bag Type Garlic Tea (마늘분말을 이용한 간편한 tea-bag형 침출차의 개발)

  • 신진희;오남순;인만진
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.4 no.3
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    • pp.279-283
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    • 2003
  • This study was carried out to establish the manufacturing formulation of tea-bag type garlic tea. In order to eliminate of garlic-specific odor and taste, the masking effect of various additives against garlic flavor was determined with sensory evaluation. Leaves of green tea, arrowroot and Solomon's seal were screened as highly effective auxiliary ingredients in garlic tea. When two materials among the selected three auxiliary materials were mixed the same percentage, overall flavor of garlic tea synergistically was enhanced. The optimum concentration of garlic powder and stevioside as a sweetener were 20∼30% and 1%, respectively. Therefore, three types formulation of garlic tea was establish. When the color, turbidity and total solid concentration of three formulated garlic teas were compared with those of commercially available formulated green tea containing unpolished rice, the latter was more yellowish color and the former was more superior to turbidity and total solid concentration.

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