• Title/Summary/Keyword: equilibrium analysis

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A Study on Decision of Cut Rock Slope Angle Applied Shear Strength of Continuum Rock Mass Induced from Hoek-Brown Failure Criterion (Hoek-Brown 파괴기준에서 유도된 연속체암반의 전단강도를 적용한 깎기 암반사면 경사 결정 연구)

  • Kim, Hyungmin;Lee, Byokkyu;Woo, Jaegyung;Hur, Ik;Lee, Junki;Lee, Sugon
    • Journal of the Korean GEO-environmental Society
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    • v.20 no.5
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    • pp.13-21
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    • 2019
  • There are many cuts or natural rock slopes that remain stable for a long time in the natural environment with steep slopes ($65^{\circ}$ to $85^{\circ}$). In terms of design practice, the rock mass consisting of similar rock condition and geological structures is defined as a good continuum rock slope, and during the process of decision making angle of this rock slope, it will be important to establish the geotechnical properties estimating method of the continuum rock on the process of stability analysis in the early stages of design and construction. In this study, the stability analysis of a good continuum rock slope that can be designed as a steep slope proposed a practical method of estimating the shear strength by induced from the Hoek-Brown failure criterion, and in addition, the design applicability was evaluated through the stability analysis of steep rock slope. The existing method of estimating the shear strength was inadequate for practical use in the design, as the equivalent M-C shear strength corresponding to the H-B envelope changes sensitively, even with small variations in confining stress. To compensate for this problem, it was proposed to estimate equivalent M-C shear strength by iso-angle division method. To verify the design applicability of the iso-angle division method, the results of the safety factor and the displacement according to the change in angle of the cut slope constructed at the existing working design site were reviewed. The safety factor is FS=16~59 on the 1:0.5 slope, FS=12~52 on the 1:0.3 slope, most of which show a 10~12 percent reduction. Displacement is 0.126 to 0.975 mm on the 1:0.5 slope, 0.152 to 1.158 mm on the 1:0.3 slope, and represents an increase of 10 to 15%. This is a slightly change in normal proportion and is in good condition in terms of stability. In terms practical the working design, it was confirmed that applying the shear strength estimated by Iso-angle division method derived from the H-B failure criterion as a universal shear strength for a good continuum rock mass slope was also able to produce stable and economic results. The procedure for stability analysis using LEM (Limit Equilibrium Analysis Method) and FEM (Finite Element Analysis Method) will also be practical in the rock slope where is not distributed fault. The study was conducted by selecting the slope of study area as a good rock condition, establishing a verification for which it can be applied universal to a various rock conditions will be a research subject later on.

Improvement of Oxygen Isotope Analysis in Seawater samples with Stable Isotope Mass Spectrometer (질량분석기를 이용한 해수 중 산소안정동위원소 분석법의 개선)

  • Park, Mi-Kyung;Kang, Dong-Jin;Kim, Kyung-Ryul
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.13 no.4
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    • pp.348-353
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    • 2008
  • Oxygen isotope has not been used actively in water mass studies because of difficulties on the analysis though it has advantages as a water mass tracer. The most popular method to analysis the oxygen isotope ratio in water samples is equilibration method: isotopic equilibrium of water with $CO_2$ at constant temperature. The precision of oxygen isotope analysis using commercial automatic $H_2O/CO_2$ equilibrator is ${\pm}0.1%o$. This value is not sufficient for studies in open ocean. The object of this study is to improve the analytical precision enough to apply open ocean studies by modification of the instrument. When sample gas is transferred by the pressure difference, the fractionation which is preferential transportation of light isotope can be occurred since the long transportation path between the equilibrator and mass spectrometer. And the The biggest source of error during the analysis is long distance and large volume of the pathway of sample gas between. Therefore, liquid nitrogen trap and high vacuum system are introduced to the system. The precisions of 14 time analysis of same seawater sample are ${\pm}0.081%o$ and ${\pm}0.021%o$ by built-in system and by modified system in this study, respectively.

Dynamic Limit and Predatory Pricing Under Uncertainty (불확실성하(不確實性下)의 동태적(動態的) 진입제한(進入制限) 및 약탈가격(掠奪價格) 책정(策定))

  • Yoo, Yoon-ha
    • KDI Journal of Economic Policy
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    • v.13 no.1
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    • pp.151-166
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    • 1991
  • In this paper, a simple game-theoretic entry deterrence model is developed that integrates both limit pricing and predatory pricing. While there have been extensive studies which have dealt with predation and limit pricing separately, no study so far has analyzed these closely related practices in a unified framework. Treating each practice as if it were an independent phenomenon is, of course, an analytical necessity to abstract from complex realities. However, welfare analysis based on such a model may give misleading policy implications. By analyzing limit and predatory pricing within a single framework, this paper attempts to shed some light on the effects of interactions between these two frequently cited tactics of entry deterrence. Another distinctive feature of the paper is that limit and predatory pricing emerge, in equilibrium, as rational, profit maximizing strategies in the model. Until recently, the only conclusion from formal analyses of predatory pricing was that predation is unlikely to take place if every economic agent is assumed to be rational. This conclusion rests upon the argument that predation is costly; that is, it inflicts more losses upon the predator than upon the rival producer, and, therefore, is unlikely to succeed in driving out the rival, who understands that the price cutting, if it ever takes place, must be temporary. Recently several attempts have been made to overcome this modelling difficulty by Kreps and Wilson, Milgram and Roberts, Benoit, Fudenberg and Tirole, and Roberts. With the exception of Roberts, however, these studies, though successful in preserving the rationality of players, still share one serious weakness in that they resort to ad hoc, external constraints in order to generate profit maximizing predation. The present paper uses a highly stylized model of Cournot duopoly and derives the equilibrium predatory strategy without invoking external constraints except the assumption of asymmetrically distributed information. The underlying intuition behind the model can be summarized as follows. Imagine a firm that is considering entry into a monopolist's market but is uncertain about the incumbent firm's cost structure. If the monopolist has low cost, the rival would rather not enter because it would be difficult to compete with an efficient, low-cost firm. If the monopolist has high costs, however, the rival will definitely enter the market because it can make positive profits. In this situation, if the incumbent firm unwittingly produces its monopoly output, the entrant can infer the nature of the monopolist's cost by observing the monopolist's price. Knowing this, the high cost monopolist increases its output level up to what would have been produced by a low cost firm in an effort to conceal its cost condition. This constitutes limit pricing. The same logic applies when there is a rival competitor in the market. Producing a high cost duopoly output is self-revealing and thus to be avoided. Therefore, the firm chooses to produce the low cost duopoly output, consequently inflicting losses to the entrant or rival producer, thus acting in a predatory manner. The policy implications of the analysis are rather mixed. Contrary to the widely accepted hypothesis that predation is, at best, a negative sum game, and thus, a strategy that is unlikely to be played from the outset, this paper concludes that predation can be real occurence by showing that it can arise as an effective profit maximizing strategy. This conclusion alone may imply that the government can play a role in increasing the consumer welfare, say, by banning predation or limit pricing. However, the problem is that it is rather difficult to ascribe any welfare losses to these kinds of entry deterring practices. This difficulty arises from the fact that if the same practices have been adopted by a low cost firm, they could not be called entry-deterring. Moreover, the high cost incumbent in the model is doing exactly what the low cost firm would have done to keep the market to itself. All in all, this paper suggests that a government injunction of limit and predatory pricing should be applied with great care, evaluating each case on its own basis. Hasty generalization may work to the detriment, rather than the enhancement of consumer welfare.

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A Study on the Reactivity Effect due to Expansion of Diagrid and Pad (Diagram와 Pad의 팽창에 의한 반응도 효과에 대한 연구)

  • Young In Kim;Keun Bae Oh;Kun Jong Yoo;Mann Cho
    • Nuclear Engineering and Technology
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    • v.16 no.2
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    • pp.70-79
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    • 1984
  • With the help of the nuclear computational system for a large LMFBR (KAERI-26 group cross section library/1DX/2DB), the reactivity coefficients for the diagrid expansion and the pad expansion at the beginning of cycle of the equilibrium core of SUPER-PHENIX I are calculated and reviewed. the core is described using R-Z geometry model, and a two-dimensional multigroup diffusion theory is used. For reference cases, reactivity calculations for radial and axial uniform expansion are performed, and also calculated are reactivity variations due to changes in material density and core volume. The reactivity coefficient for the diagrid expansion is calculated to be -0.553pcm/mil. The temperature coefficient corresponding to the above value is -1.0766pcm/$^{\circ}C$ and is well in accord with the French datum of -1.09pcm/$^{\circ}C$ within 1.2% difference. With the use of 4he calculational method for the diagrid expansion effect, reactivity calculations for the pad expansion bringing about nonuniform expansion are performed, which show that the calculational method is very useful in the analysis of the pad expansion effect. The reactivity coefficients for the pad expansion are calculated to be -0.2743 pcm/mil and -0.2786pcm1mi1 for the averaged expansion model and for the integrated pancake model, respectively. Under the assumption of the free expanding core the temperature reactivity coefficients for each model are obtained to be -0.5766pcm/$^{\circ}C$ and -0.5858pcm/$^{\circ}C$, both of which agree with the French datum of -0.574pcm/$^{\circ}C$ within 2% difference.

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Analysis on Forces Acting on the Contact Lens Fitted on the Cornea (콘택트 렌즈에 작용하는 힘의 해석)

  • Kim, Dae-Soo
    • Journal of Korean Ophthalmic Optics Society
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    • v.7 no.2
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    • pp.1-11
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    • 2002
  • A mathematical model is proposed to analyze the force; acting on the hard contact lens fitted on the cornea. The model incorporates the nonlinear equations and their numerical solution program, based on the formulations of surface tension force arising from the capillary action in the tear-film layer between the lens and cornea. The model simulates how the adhesion between lens and cornea varies according to the base curves and diameters of the lenses. When the spherical lens is fitted on the spherical cornea it is to rotate downward due to the weight of lens itself until it reaches an equilibrium position along the cornea where the counter(upward) moment caused by net force between the upper and lower portion of the periphery of lens. It is found that both the adhesion and displacement of lens along the cornea, where the gravity of lens balances the capillary-induced upward force, increases rapidly as the base curve of lens increases, i.e., as the lens gets flatter, while the increase in the diameter of lenses has resulted in the less increase in the rotation and adhesion. With the base curve and diameters of lenses being remained constant the increase in surface tension of tear film yields the increase in the adhesion between the cornea and lens while the initial rotation of lens is inversely proportional to the surface tension of the tear film.

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An Improved Bond Slip Model of CFT Columns for Nonlinear Finite Element Analysis (CFT 기둥의 비선형 유한요소해석을 위한 개선된 강관-콘크리트 간 부착 모델 개발)

  • Kwon, Yangsu;Kwak, Hyo-Gyoung;Hwang, Ju-Young;Kim, Jin-Kook;Kim, Jong-Min
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.28 no.2
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    • pp.213-220
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    • 2015
  • CFT column has a lot of structural advantages due to the composite behavior between in-filled concrete and steel tube. This paper deals with the development of an effective numerical model which can consider the bond-slip behavior between both components of concrete matrix and steel tube without taking double nodes. Since the applied axial load to in-filled concrete matrix is delivered to steel tube by the confinement effect and the friction, the governing equation related to the slip behavior can be constructed on the basis of the force equilibrium and the compatability conditions. In advance, the force and displacement relations between adjacent two nodes make it possible to express the slip behavior with the concrete nodes only. This model results in significant savings in the numerical modeling of CFT columns to take into account the effect of bond-slip. Finally, correlation studies between numerical results and experimental data are conducted to verifying the efficiency of the introduced numerical model.

Effects of Inflation Indexed Excise Duties on Transportation Fuel Consumption Using Demand Analysis based on the Linear Expenditure System in Korea (선형지출체계 수요함수 추정을 통한 수송용 유류 종량세의 물가연동제 도입효과 분석)

  • Sung, Myung Jae
    • Environmental and Resource Economics Review
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    • v.26 no.2
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    • pp.257-286
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    • 2017
  • This paper estimates the effects of imaginary repeated increases in excise duties on fuel oil consumption and on their income redistribution according to changes in consumer price index, if the inflation indexation system was introduced right after the second Energy Tax Reform ended in July, 2007 in Korea. In fact, nominal excise rates have not been adjusted since 2007. As a result, the real excise rates on fuel oils have been diminished inversely proportional to the consumer price index. Own- and cross-price elasticities of fuel oils such as gasoline and diesel oil are estimated under the general equilibrium framework based on the linear expenditure system. Counterfactual analyses through microsimulation in a static model are adopted to estimate the effects of introducing inflation indexation into the fuel tax in 2007 when the second Energy Tax reform ended on the fuel consumption and income redistribution in 2014. Microsimulations suggest that its introduction could have reduced the consumption of gasoline and diesel oil by 8.8% and 5.4%, respectively, ending up with increased excise revenue by 11.9%. The revenue increase in spite of decreased consumption is mainly because their demands are price inelastic. It could also have increased positive income redistributive effect by 0.01%p (from 0.12% to 0.13%), which is measured in terms of percentage decrease in Gini coefficient. In other words, the fuel excise on the two fuel oils decreased by 0.13% the Gini coefficient of before and after fuel tax income in 2014. This implies that the inflation indexation could have enlarged the income redistributive effect up to 0.13% in 2014, if it is introduced in 2007.

A Study on the Diseases and Pharmacy of the Soumin's Sinsooyul-Pyoyul-Byung theory (소음인(少陰人) 신수열표열병론(腎受熱表熱病論)의 병증(病證) 및 약리(藥理)에 대한 연구(硏究))

  • Joo, Jong-Cheon;Kim, Kyung-Yo
    • Journal of Sasang Constitutional Medicine
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    • v.9 no.2
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    • pp.67-94
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    • 1997
  • The main purpose of this study is to arrange the diseases, principal medicinal substances and the prescriptions for the Soumin's Sinsooyul-Pyoyul-Byung(少陽人 腎受熱表熱病) by historical examination in the viewpoint of the Constitutional Medicine(四象醫學). In this study, first I collected the original texts of the diseases and priscriptions in Dongyi-Soose-Bowon(東醫壽世保元), and described the development process of the Soumin(少陽人)'s diseases and priscriptions by comparing with the contents in Dongyi-Soose-Bowon(東醫壽世保元). Next, I collected the efficacy of the medicinal substances and priscriptions by the examination of successive literatures referred it, and tried to explain the efficacy of each medicinal substances in the viewpoint of the Constitutional Medicine(四象醫學) by the analysis of successive literatures. As a result, the conclusions could be summarized as follows. 1. The Differentiation of Syndromes(辦證) in the Existing Medicine(旣存醫學) was formed according to the Eight Principal Syndromes(八綱), the Five Elements(五行), the Merdian system(經絡), therefore there were many confusions with the changes of the times. The differentiation of Syndromes(辦證) in the Constitutional Medicine(四象醫學) was formed according to the pathological change of Ascending and Descending Yin Yang(陰陽升降) in the Four Internal Organs(四臟), therefore, there was the consistency in the recognition of diseases. 2. The classification of the Soumin's Pyoyul-Byung(少陽人 表熱病) was divided into Yukuang Disease(鬱狂證) and Mangyang Disease(亡陽證) according to sweating or not. The conception of these diseases was mostly achived in Shanhanlun(優寒論). The treatment of Shanhanlun(優寒論) was alike to that of Dongyi-Soose-Bowon(東醫壽世保元) in a part. 3. Je ma, Lee thinked that the cause of the Soumin's Pyoyul-Byung(少陽人 表熱病) is the breakdown of the balanced equilibrium in ascending and descending Yin Yang(陰陽升降) for a Large Sin and a Small Bi(腎大脾小), and it is treated by warming and ascending Yang(溫補升陽). 4. The medicinal substances composing prescriptions for the Soumin's Pyoyul-Byung(少陰人 表熱病) is characterized with the efficacy of Ascending Yang and supplying Qi(升陽益氣) and regulating the digestive organs with the efficacy of warming it. 5. The medicinal substances composing the precriptions for the Soumin's Pyoyul-Byung(少陰人 表熱病) is divided into four parts with the state of Yang Qi(陽氣) in the disease it used. 6. The purpose of prescriptions for the Soumin's Pyoyul-Byung(少陰人 表熱病) is to strengthen the Soumin(少陰人)'s Yangnan Qi(陽暖之氣). Je ma, Lee kept the principle not to mix with another constitution's medicinal substances in the creation of the priscription.

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An Analysis on the Over-Potentially Deposited Hydrogen at the Polycrystalline $Ir/H_2SO_4$ Aqueous Electrolyte Interface Using the Phase-Shift Method (위상이동 방법에 의한 다결정 $Ir/H_2SO_4$ 수성 전해질 계면에서 과전위 수소흡착에 관한 해석)

  • Chun Jagn Ho;Mun Kyeong Hyeon
    • Journal of the Korean Electrochemical Society
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    • v.3 no.2
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    • pp.109-114
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    • 2000
  • The relation between the phase-shift profile fur the intermediate frequencies and the Langmuir adsorption isotherm at the poly-Ir/0.1 M $H_2SO_4$ aqueous electrolyte interface has been studied using ac impedance measurements, i.e., the phase-shift methods. The simplified interfacial equivalent circuit consists of the serial connection of the electrolyte resistance $(R_s)$, the faradaic resistance $(R_F)$, and the equivalent circuit element $(C_P)$ of the adsorption pseudoca-pacitance $(C_\phi)$. The comparison of the change rates of the $\Delta(-\phi)/{\Delta}E\;and\;\Delta{\theta}/{\Delta}E$ are represented. The delayed phase shift $(\phi)$ depends on both the cathode potential (E) and frequency (f), and is given by $\phi=tan^{-1}[1/2{\pi}f(R_s+R_F)C_P]$. The phase-shift profile $(-\phi\;vs.\;E)$ for the intermediate frequency (ca. 1 Hz) can be used as an experimental method to determine the Langmuir adsorption isotherm $(\theta\;vs.\;E)$. The equilibrium constant (K) for H adsorption and the standard free energy $({\Delta}G_{ads})$ of H adsorption at the poly-Ir/0.1 M $H_2SO_4$ electrolyte interface are $2.0\times10^{-4}$ and 21.1kJ/mol, respectively. The H adsorption is attributed to the over-potentially deposited hydrogen (OPD H).

Analysis on the Frumkin Adsorption Isotherm of the Over-Potentially Deposited Hydrogen (OPD H) at the Polycrystalline Ni | Alkaline Aqueous Electrolyte Interface Using the Phase-Shift Method

  • Chun Jang H.;Jeon Sang K.
    • Journal of the Korean Electrochemical Society
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    • v.4 no.4
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    • pp.146-151
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    • 2001
  • The Frumkin adsorption isotherm of the over-potentially deposited hydrogen (OPD H) for the cathodic $H_2$ evolution reaction (HER) at the poly-Ni|0.05M KOH aqueous electrolyte interface has been studied using the phase-shift method. The behavior of the phase shift $(0^{\circ}\leq{\phi}\leq90^{\circ})$ for the optimum intermediate frequency corresponds well to that of the fractional surface coverage $(1\geq{\theta}\geq0)$ at the interface. The phase-shift method, i.e., the Phase-shift profile $(-{\phi}\;vs.\;E)$ for the optimum intermediate frequency, can be used as a new method to estimate the Frumkin adsorption isotherm $(\theta\;vs.\;E)$ of the OPD H for the cathodic HER at the interface. At the poly-Ni|0.05M KOH aqueous electrolyte interface, the rate (r) of change of the standard free energy of the OPD H with $\theta$, the interaction parameter (g) for the Frumkin adsorption isotherm, the equilibrium constant (K) for the OPD H with $\theta$, and the standard free energy $({\Delta}G_{\theta})$ of the OPD H with ${\theta}$ are $24.8kJ mol^{-1},\;10,\;5.9\times10^{-6}{\leq}K{\leq}0.13,\;and\;5.1\leq{\Delta}G_{\theta}\leq29.8kJ\;mol^{-1}$. The electrode kinetic parameters $(r,\;g,\;K,\;{\Delta}G_{\theta})$ depend strongly on ${\theta} (0{\leq}{\theta}{\leq}1)$.