• Title/Summary/Keyword: fluid form

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Experimental study on the mechanical property of coal and its application

  • Jiang, Ting T.;Zhang, Jian H.;Huang, Gang;Song, Shao X.;Wu, Hao
    • Geomechanics and Engineering
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    • v.14 no.1
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    • pp.9-17
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    • 2018
  • Brazilian splitting tests, uniaxial compression tests and triaxial compression tests are carried out on the coal samples cored from Shanxi group $II_1$ coal seam of Jiaozuo coal mine, Henan province, China, to obtain their property parameters. Considering the bedding has notable effect on the property parameter of coal, the samples with different bedding angles are prepared. The effects of bedding on the anisotropic characteristics of the coal seam are investigated. A geological geomechanical model is built based on the geology characteristics of the Jiaozuo coal mine target reservoir to study the effects of bedding on the fracture propagations during hydraulic fracturing. The effects of injection pressure, well completion method, in-situ stress difference coefficient, and fracturing fluid displacement on the fracture propagations are investigated. Results show bedding has notable effects on the property parameters of coal, which is the key factor affecting the anisotropy of coal. The hydraulic cracks trends to bifurcate and swerve at the bedding due to its low strength. Induced fractures are produced easily at the locations around the bedding. The bedding is beneficial to form a complicated fracture network. Experimental and numerical simulations can help to understand the effects of bedding on hydraulic fracturing in coalbed methane reservoirs.

A young child of anti-NMDA receptor encephalitis presenting with epilepsia partialis continua: the first pediatric case in Korea

  • Kim, Eun-Hee;Kim, Yeo Jin;Ko, Tae-Sung;Yum, Mi-Sun;Lee, Jun Hwa
    • Clinical and Experimental Pediatrics
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    • v.59 no.sup1
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    • pp.133-138
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    • 2016
  • Anti-N-methyl D-aspartate receptor (anti-NMDAR) encephalitis, recently recognized as a form of paraneoplastic encephalitis, is characterized by a prodromal phase of unspecific illness with fever that resembles a viral disease. The prodromal phase is followed by seizures, disturbed consciousness, psychiatric features, prominent abnormal movements, and autonomic imbalance. Here, we report a case of anti-NMDAR encephalitis with initial symptoms of epilepsia partialis continua in the absence of tumor. Briefly, a 3-year-old girl was admitted to the hospital due to right-sided, complex partial seizures without preceding febrile illness. The seizures evolved into epilepsia partialis continua and were accompanied by epileptiform discharges from the left frontal area. Three weeks after admission, the patient's seizures were reduced with antiepileptic drugs; however, she developed sleep disturbances, cognitive decline, noticeable oro-lingual-facial dyskinesia, and choreoathetoid movements. Anti-NMDAR encephalitis was confirmed by positive detection of NMDAR antibodies in the patient's serum and cerebrospinal fluid, and her condition slowly improved with immunoglobulin, methylprednisolone, and rituximab. At present, the patient is no longer taking multiple antiepileptic or antihypertensive drugs. Moreover, the patient showed gradual improvement of motor and cognitive function. This case serves as an example that a diagnosis of anti-NMDAR encephalitis should be considered when children with uncontrolled seizures develop dyskinesias without evidence of malignant tumor. In these cases, aggressive immunotherapies are needed to improve the outcome of anti-NMDAR encephalitis.

Numerical Simulation of Tsunami Force Acting on Onshore Bridge (for Tsunami Bore) (연안교량에 작용하는 지진해일파력에 관한 수치시뮬레이션(단파의 경우))

  • Lee, Kwang-Ho;Woo, Kyung-Hwan;Kim, Do-Sam;Jeong, Ik-Han
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.29 no.1
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    • pp.46-61
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    • 2017
  • In the present work, the interaction analysis between tsunami bore and onshore bridge is approached by a numerical method, where the tsunami bore is generated by difference of upstream side and downstream side water levels. Numerical simulation in this paper was carried out by TWOPM-3D(three-dimensional one-field model for immiscible two-phase flows), which is based on Navier-Stokes solver. In order to verify the applicability of force acting on an onshore bridge, numerical results and experimental results were compared and analyzed. From this, we discussed the characteristics of horizontal force and vertical force(uplift force and downward force) changes including water level and velocity change due to the tsunami bore strength, water depth, onshore bridge form and number of girder. Furthermore, It was revealed that the entrained air in the fluid flow highly affected the vertical force.

A Case Report of Rhabdomyolysis Induced by a Combination of Exercise, Alcohol, and Medication (운동, 알코올, 약물 등 복합적 요인으로 유발된 횡문근융해증 환자 치험 1례)

  • Jin, Joon-soo;Lee, Hee-jung;Min, Baek-ki;Kong, Won-ho;Seo, Ho-seok;Kim, Jin-won
    • The Journal of Internal Korean Medicine
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    • v.39 no.5
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    • pp.904-913
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    • 2018
  • Rhabdomyolysis is a syndrome that evokes either myopathy or cola-colored urine with elevated creatine kinase and myoglobin levels. The most common complication of rhabdomyolysis is acute renal failure (ARF). A large quantity of fluid must be injected promptly the first time symptoms appear, whereas sequela of symptoms has remained in the long run. In this report, a 58-year-woman was diagnosed with ARF due to rhabdomyolysis induced by exercise, alcohol, and medication. A treatment of acupuncture and herbal medicines was carried out for over 2 months. To evaluate the condition of the patient's lower limb, a short form of the McGill Pain Questionnaire, Visual Analogue Scale (VAS), European Quality of Life-5 Dimensions (EQ-5D), and Manual Muscle Test (MMT) points were used. As a result, clinical symptoms and quality of life improved noticeably after treatment with Korean medicine. This suggests that Korean medicine has an effect on rhabdomyolysis.

Design and Pharmaceutical Evaluation of Biphenyl Dimethyl Dicarboxylate Elastic Capsules (비페닐디메칠디카르복실레이트 연질캅셀제의 설계 및 제제학적 평가)

  • 전인구;곽혜선;문지현
    • Biomolecules & Therapeutics
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    • v.4 no.4
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    • pp.419-427
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    • 1996
  • To solubilize practically insoluble biphenyl dimethyl dicarboxylate (DDB), which has been used for the treatment of chronic hepatitis as tablets or hard capsules, the solubilities of DDB in various hydrophilic, oily and hydrocarbon vehicles, and aqueous surfactant solutions were measured by high performance liquid chromatography. It was found that, among the vehicles studied, polyethylene glycol (PEG) 300 revealed the best solvency, and the solubility reached 17.6 mg/ml at 37$^{\circ}C$. The addition of glycyrrhizic acid ammonium salt (GAA) to DDB-PEG 300 solution (5-20 mg/g) inhibited the formation of precipitates, and at the concentration of 10 mg/g, any precipitaction was not observed even after 2 years at 4$^{\circ}C$. Furthermore, GAA markedly enhanced the permeation of DDB through the rabbit duodenal mucosa in a concentration dependent manner. The addition of copolyvidone (ca. 1.0%) to DDB-GAA-PEG 300 system (1 : 0.5 97.5 w/w) was most effective in preventing the considerable precipitation of DDB-PEG 300 solution (7.5 mg/750 mg) when mixed with water of 300-900 ml at 37$^{\circ}C$. GAA showed a synergistic effect in the prevention of precipitate formation. This finding suggests that this DDB formulation may form less precipitation when DDB soft capsules disintegrate and diffuse into the gastrointestinal fluid, resulting in improving the bioavailability Dissolution rate of DDB (7.5 mg) from sort elastic capsules of DDB-GAA-PEG 300 system was rapid. The supersaturation state was maintained for 2 hr at the concentration of 7.35$\pm$3.3 mg in 900 ml of water without precipitation. The total amount of DDB dissolved from this new formulation was 5.3 and 6.1 times higher, when compared to marketed DDB tablets (25 mg) and capsules (7.5 mg), respectively.

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Finite Element Analysis of Powder Injection Molding Filling Process Including Yield Stress and Slip Phenomena (항복응력과 미끄럼현상을 고려한 분말사출성형 충전공정의 유한요소해석)

  • 박주배;권태헌
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.17 no.6
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    • pp.1465-1477
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    • 1993
  • Powder Injection Molding(PM) is an advanced and complicated technology for manufacturing ceramic or metal products making use of a conventional injection molding process, which is generally used for plastic products. Among many technologies involved in the successful PIM, injection molding process is one of the key steps to form a desired shape out of powder/binder mixtures. Thus, it is of great importance to have a numerical tool to predict the powder injection molding filling process. In this regard, a finite element analysis system has been developed for numerical simulations of filling process of powder injection molding. Powder/polymer mixtures during the filling pro cess of injection molding can be rheologically characterized as Non-Newtonian fluids with a so called yield phenomena and have a peculiar feature of apparent slip phenomena on the wall boundaries surrounding mold cavity. Therefore, in the present study, a physical modeling of the filling process of powder/polymer mixtures was developed to take into account both the yield stress and slip phenomena and a finite element formulation was developed accordingly. The numerical analysis scheme for filling simulation is accomplished by combining a finite element method with control volume technique to simulate the movement of flow front and a finite difference method to calculate the temperature distribution. The present study presents the modeling, numerical scheme and some numerical analysis results showing the effect of the yield stress and slip phenomena.

Analysis of the Flow Field around a Hydrofoil Catamaran by Using Model Experiment and Numerical Analysis (모형시험 및 수치해석을 통한 수중익쌍동선 주위의 유동장 해석)

  • Na, Y.I.;Lee, Y.G.
    • Journal of the Society of Naval Architects of Korea
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    • v.34 no.4
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    • pp.61-71
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    • 1997
  • Numerical and experimental studies are carried out to analyse the resistance characteristics of a hydrofoil catamaran which is advancing on calm water with uniform speed. For the hydrofoil catamaran with modified Wigley hull which has asymmetric transverse section and transom stem, the studies are carried out for the range of Froude number 0.2 to 1.0 and the angle of attack of the hydrofoil $0.0^{\circ}$ to $3.0^{\circ}$. The model tests are carried out in the ship model basin of Inha University. Also the numerical computations using a finite difference method are performed for the simulations of fluid flow around the hull form and the results are compared with the results of the model tests. The present computation results show well quantitative agreement with the experimental results. The experimental results show that the shape and angle of attack of the foils exerts a considerable influence on the running posture and resistance performance of ship.

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Nonlinear Fluid Forces on Hinged Wavemakers (힌지형 조파기에 작용하는 비선형 파력)

  • Kim, Tae-In;Rocbert T. Hudspeth
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.2 no.4
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    • pp.208-222
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    • 1990
  • The nonlinear hydrodynamic pressure force and moment on hinged wavemakers of variable-draft are presented. A closed-form solution (correct to second-order) for the nonlinear wavemaker boundary value problem has been obtained by employing the Stokes perturbation expansion scheme. The physical significance of the second-order contributions to the hydrodynamic pressure moment are examined in detail. Design curves are presented which demonstrate both the magnitude of the second-order nonlinearities and the effects of the variable-draft hinge height. The second-order contributions to the total hydrodynamic force and moment consist of a time-dependent and a steady part. The sum of the first and second-order pressure force and moment show a significant increase over those predicted by linear wavemaker theory. The second-order effects are shown to vary with both relative water depth and wave amplitude. The second-order dynamic effects are relatively more important for hinged wavemakers with shallower drafts.

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Effect of Different Silages for TMR on In vitro Rumen Simulative Fermentation

  • Mbiriri, David Tinotenda;Oh, Seong Jin;Choi, Nag-Jin
    • Journal of The Korean Society of Grassland and Forage Science
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    • v.32 no.4
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    • pp.379-386
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    • 2012
  • In this study, the in vitro fermentation parameters of whole crop barley (WCBS-TMR) and Italian ryegrass (IRGS-TMR) silage total mixed rations were compared. A rice straw based diet (RSBD), which was a mixture of rice straw and concentrate (60:40), was used as the control. The feeds were incubated in buffered rumen fluid for 3, 6, 9, 12, 24, 48 and 72 hours at $39^{\circ}C$. At the end of each incubation period the following parameters were determined, total gas, pH, ammonia nitrogen ($NH_3$-N), volatile fatty acids (VFA) and then the acetate to propionate ratio (A/P) was calculated. The dietary treatments did not affect (p>0.05) the overall production of $NH_3$-N, gas, total VFA and all the individual VFA, with the exception of n-butyrate (p<0.001). The treatment diets significantly affected the A/P ratio (p<0.01). The control diet resulted in the lowest A/P ratios, followed by WCBS-TMR and lastly IRGS-TMR had the highest ratios. Gas production was not different between treatments, suggesting a probable similar level of digestibility when treatments are fed to animals. It can therefore be concluded from the present study that WCBS and IRGS are of almost an equivalent nutritional value when incubated in a TMR form. WCBS-TMR however resulted in lower A/P ratios than IRGS-TMR, which is indicative of a more energy efficient diet.

Geology and Ore Deposit of the Apdong Nb-Ta Mine, North Korea (북한 압동 니오븀-탄탈륨(Nb-Ta) 광산의 지질 및 광상)

  • 이재호;김유동
    • Economic and Environmental Geology
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    • v.36 no.6
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    • pp.407-413
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    • 2003
  • The geology of the Apdong Nb-Ta deposit, is hosted by alkali metasomatites, consist of Upper Proterozoic sedimentary rocks, alkali syenites(Hoamsan intrusive) of Phyonggang Complex(late Paleozoic to early Mesozoic), Jurassic granite and Quaternary basalt. Alkali syenites are distinguished as alkali amphibole-pyroxene syenite, alkali amphibole-biotite syenite, biotite-nepheline syenite, biotite syenite, and quartz-alkali amphibole-pyroxene syenite. Alkali metasomatites are the products of intense post-magnatic metasomatism, and form the Nb-Ta ore bodies as the belt, irregular vein and lenticular types in the southern part of Hoamsan intrusive. The ore mineralization is characterized by the occurrence of pyrochlore, zircon, and small amounts of columbite, fergusonite. magnetite, fluorite, molybdenite, ilmenite, titanite, apatite, and monazite. Pyrochlore is one of the niobium/tantalum oxides and contains substantial amounts of rare earths and radioactive elements. The compositional varieties of pyrochlore can be defined: (1) enriched in tantalum, uranium and cerium, (2) substantially tantalum- and fluorine-poor, and (3) enriched in thorium or barium. The geochemical characteristics, ore textures and mineral occurrences indicate that alkali metasomatism of the mineralizing fluid was the dominant ore-forming process.