• Title/Summary/Keyword: equilibrium test

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Elasto-plastic Joint Finite Element Analysis of Root-pile Using the Direct Shear Test Model (직접전단시험모델에 의한 뿌리말뚝의 탄소성조인트 유한요소해석)

  • Han, Jung-Geun
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.5 no.4
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    • pp.19-30
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    • 2002
  • The stability of slope using root-pile like to the reinforcements is affected by the interaction behavior mechanism of soil-reinforcements. Through the studying on the interaction in joint of its, therefore, the control roles can be find out in installed slope. In study, the stress level ratio based on the insert angle of installed reinforcements in soil used to numerical analysis, which was results from the duty direct shear test in Lab. The maximum shear strain variation on the reinforcements was observed at insert angle, which was approximately similar to the calculated angle based on the equation proposed by the Jewell. The elasto-plastic joint model on the contact area of soil-reinforcements was presumed, the reinforced soil assumed non-linear elastic model and the reinforcements supposed elastic model, respectively. The finite element analysis of assumed models was performed. The shear strain variation of non-reinforced state obtained by the FEM analysis including elasto-plastic joint elements were shown the rationality of general limit equilibrium analysis for the slope failure mode on driving zone and resistance zone, which based on the stress level step according to failure ratio. Through the variation of shear strain for the variation of inserting angle of reinforcements, the different mechanism on the bending and the shear resistance of reinforcements was shown fair possibility.

Shear strength evaluation of RC solid piers of high-speed railway bridges in China

  • Guo, Wei;Fan, Chao;Cui, Yao;Zeng, Chen;Jiang, Lizhong;Yu, Zhiwu
    • Structural Engineering and Mechanics
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    • v.78 no.4
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    • pp.413-423
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    • 2021
  • Piers are the main lateral force-resisting members of high-speed railway (HSR) bridges used in China and are characterized by low axial load ratios, low longitudinal reinforcement ratios, low stirrup ratios, and high shear span ratios. It is well known that flexural, flexural-shear, and shear failures of piers may occur during an earthquake. In this study, a new shear strength model was developed to simulate the seismic failure of HSR solid piers accurately. First, low cyclic-loading test data of solid piers obtained in recent years were collected to set up a database for model verification. Second, based on the test database, the applicability of existing shear strength models was evaluated. Finally, a new shear strength model for HSR solid piers with round-ended cross-sections was derived based on the truss model and ultimate equilibrium theory. In comparison with existing models, it was demonstrated that the proposed model could be used to predict the shear strength of HSR piers more accurately.

Sectoral Stock Markets and Economic Growth Nexus: Empirical Evidence from Indonesia

  • HISMENDI, Hismendi;MASBAR, Raja;NAZAMUDDIN, Nazamuddin;MAJID, M. Shabri Abd.;SURIANI, Suriani
    • The Journal of Asian Finance, Economics and Business
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    • v.8 no.4
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    • pp.11-19
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    • 2021
  • This study aims to analyze the causality relationship between sectoral stock markets (agricultural, financial, industrial, and mining sectors) and economic growth in the short and long term as well as to analyze whether it has similar types or not. The data used is quarterly time-series data (first quarter 2009 to fourth 2019). To determine the causality relationship, this study conducts a variable and multivariate causality test. The results of the varying granger causality test show that there is only a one-way relationship, where the economic growth of the agriculture sector affects its shares. A one-way relationship also occurs in stocks of the industrial sector, which has an influence on economic growth. The multivariate causality test shows that the economic growth of the agricultural sector has a two-way causality relationship, and it also exists between the industrial sector and the financial sector stock markets. The two-way causality relationship between the stock market and sectoral economic growth is a convergence towards long-term equilibrium. The findings of this study suggest that the government through the Financial Services Authority and the Indonesia Stock Exchange have to maintain stability in the stock market as a supporter of the national economy.

Wind-sand tunnel experiment on the windblown sand transport and sedimentation over a two-dimensional sinusoidal hill

  • Lorenzo Raffaele;Gertjan Glabeke;Jeroen van Beeck
    • Wind and Structures
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    • v.36 no.2
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    • pp.75-90
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    • 2023
  • Turbulent wind flow over hilly terrains has been extensively investigated in the scientific literature and main findings have been included in technical standards. In particular, turbulent wind flow over nominally two-dimensional hills is often adopted as a benchmark to investigate wind turbine siting, estimate wind loading, and dispersion of particles transported by the wind, such as atmospheric pollutants, wind-driven rain, windblown snow. Windblown sand transport affects human-built structures and natural ecosystems in sandy desert and coastal regions, such as transport infrastructures and coastal sand dunes. Windblown sand transport taking place around any kind of obstacle is rarely in equilibrium conditions. As a result, the modelling of windblown sand transport over complex orographies is fundamental, even if seldomly investigated. In this study, the authors present a wind-sand tunnel test campaign carried out on a nominally two-dimensional sinusoidal hill. A first test is carried out on a flat sand fetch without any obstacle to assess sand transport in open field conditions. Then, a second test is carried out on the hill model to assess the sand flux overcoming the hill and the morphodynamic evolution of the sand sedimenting over its upwind slope. Finally, obtained results are condensed into a dimensionless parameter describing its sedimentation capability and compared with values resulting from other nominally two-dimensional obstacles from the literature.

A novel laboratory method for measuring the hydraulic conductivity of dredged slurry with high water contents

  • Cong Mou;Jian-wen Ding;Jian-hua Wang;Xing Wan
    • Geomechanics and Engineering
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    • v.33 no.3
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    • pp.317-326
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    • 2023
  • Accurately measuring the hydraulic conductivity of dredged slurry (HCODS) is a difficult task and usually requires highly developed experimental techniques. To resolve such problem, this paper presents a novel laboratory method, where a double drainage sedimentation test (DDST) is proposed to generate a downward seepage after the end of primary consolidation (EOP). Based on the established stress equilibrium equations, it is figured out that the determination of local hydraulic gradients requires the effective stress distribution to be measured. Accordingly, an additional single drainage sedimentation test (SDST) with the same initial water content is performed in the novel laboratory method, which can be utilized to establish the relationship between effective stress and water content for investigated slurry. Thus, HCODS can be determined via a pair of SDST and DDST, with the water contents after the EOP measured. The corresponding calculation procedure is given in details. With a simply-designed settling column, the hydraulic conductivity tests were performed on three types of dredged slurry. The results demonstrated the effectiveness of the novel laboratory method in measuring HCODS.

Glass Dissolution Rates From MCC-1 and Flow-Through Tests

  • Jeong, Seung-Young
    • Proceedings of the Korean Radioactive Waste Society Conference
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    • 2004.06a
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    • pp.257-258
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    • 2004
  • The dose from radionuclides released from high-level radioactive waste (HLW) glasses as they corrode must be taken into account when assessing the performance of a disposal system. In the performance assessment (PA) calculations conducted for the proposed Yucca Mountain, Nevada, disposal system, the release of radionuclides is conservatively assumed to occur at the same rate the glass matrix dissolves. A simple model was developed to calculate the glass dissolution rate of HLW glasses in these PA calculations [1]. For the PA calculations that were conducted for Site Recommendation, it was necessary to identify ranges of parameter values that bounded the dissolution rates of the wide range of HLW glass compositions that will be disposed. The values and ranges of the model parameters for the pH and temperature dependencies were extracted from the results of SPFT, static leach tests, and Soxhlet tests available in the literature. Static leach tests were conducted with a range of glass compositions to measure values for the glass composition parameter. The glass dissolution rate depends on temperature, pH, and the compositions of the glass and solution, The dissolution rate is calculated using Eq. 1: $rate{\;}={\;}k_{o}10^{(ph){\eta})}{\cdot}e^{(-Ea/RT)}{\cdot}(1-Q/K){\;}+{\;}k_{long}$ where $k_{0},\;{\eta}$ and Eaare the parameters for glass composition, pH, $\eta$ and temperature dependence, respectively, and R is the gas constant. The term (1-Q/K) is the affinity term, where Q is the ion activity product of the solution and K is the pseudo-equilibrium constant for the glass. Values of the parameters $k_{0},\;{\eta}\;and\;E_{a}$ are the parameters for glass composition, pH, and temperature dependence, respectively, and R is the gas constant. The term (1-Q/C) is the affinity term, where Q is the ion activity product of the solution and K is the pseudo-equilibrium constant for the glass. Values of the parameters $k_0$, and Ea are determined under test conditions where the value of Q is maintained near zero, so that the value of the affinity term remains near 1. The dissolution rate under conditions in which the value of the affinity term is near 1 is referred to as the forward rate. This is the highest dissolution rate that can occur at a particular pH and temperature. The value of the parameter K is determined from experiments in which the value of the ion activity product approaches the value of K. This results in a decrease in the value of the affinity term and the dissolution rate. The highly dilute solutions required to measure the forward rate and extract values for $k_0$, $\eta$, and Ea can be maintained by conducting dynamic tests in which the test solution is removed from the reaction cell and replaced with fresh solution. In the single-pass flow-through (PFT) test method, this is done by continuously pumping the test solution through the reaction cell. Alternatively, static tests can be conducted with sufficient solution volume that the solution concentrations of dissolved glass components do not increase significantly during the test. Both the SPFT and static tests can ve conducted for a wide range of pH values and temperatures. Both static and SPFt tests have short-comings. the SPFT test requires analysis of several solutions (typically 6-10) at each of several flow rates to determine the glass dissolution rate at each pH and temperature. As will be shown, the rate measured in an SPFt test depends on the solution flow rate. The solutions in static tests will eventually become concentrated enough to affect the dissolution rate. In both the SPFt and static test methods. a compromise is required between the need to minimize the effects of dissolved components on the dissolution rate and the need to attain solution concentrations that are high enough to analyze. In the paper, we compare the results of static leach tests and SPFT tests conducted with simple 5-component glass to confirm the equivalence of SPFT tests and static tests conducted with pH buffer solutions. Tests were conducted over the range pH values that are most relevant for waste glass disssolution in a disposal system. The glass and temperature used in the tests were selected to allow direct comparison with SPFT tests conducted previously. The ability to measure parameter values with more than one test method and an understanding of how the rate measured in each test is affected by various test parameters provides added confidence to the measured values. The dissolution rate of a simple 5-component glass was measured at pH values of 6.2, 8.3, and 9.6 and $70^{\circ}C$ using static tests and single-pass flow-through (SPFT) tests. Similar rates were measured with the two methods. However, the measured rates are about 10X higher than the rates measured previously for a glass having the same composition using an SPFT test method. Differences are attributed to effects of the solution flow rate on the glass dissolution reate and how the specific surface area of crushed glass is estimated. This comparison indicates the need to standardize the SPFT test procedure.

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Study on Effect of Warmth Therapy Nursing Intervention Program after Laparoscopic Cholecystectomy (복강경담낭절제술 후 가온요법 간호중재 프로그램 적용 효과)

  • Lee, Jung-Geun
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.21 no.7
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    • pp.350-356
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    • 2020
  • Purpose: This study is a non-equilibrium control-like experimental study that attempts to develop a nursing intervention plan and to present basic data by grasping the effect of the heating therapy nursing intervention program on patients entering the recovery room after surgery. Method: The subjects of the study were 31 in an experimental group and 31 in a control group who applied one heating therapy program located in D city. The warming therapy was conducted in a recovery room in the range of 38 to 43℃ through a heater. The general characteristics of the subjects were determined by real number and percentage, and a homogeneity test between the experimental group and the control group was determined by 𝑥2-test and independent t-test. The difference in body temperature, pain, and tremor over time between the two groups was determined by repeated measure ANOVA. Results: First, the results of repeated measurements immediately after surgery showed significant differences in body temperature, pain, and tremor between the two groups. Second, temperature comfort showed a significant difference. Conclusion: The results confirmed that there was a positive effect on the patient in the intervention of warming therapy after surgery.

A Study on the Adsorptive Removal of Heavy Metals Using Inflated Vermiculites (팽창질석을 이용한 중금속 흡착제거에 관한 연구)

  • Lee, Junki;Koh, Taehoon;Kim, Sukyung;Lee, Taeyoon
    • Journal of the Korean GEO-environmental Society
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    • v.10 no.6
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    • pp.61-68
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    • 2009
  • The main objective of this study was to examine the removal of heavy metals from water by inflated vermiculites. The component of vermiculites was analyzed by XRF, and the concentration of metal ion was measured by ICP-AES. Serial batch kinetic tests and batch sorption tests were conducted to determine the removal characteristics for heavy metals in aqueous solutions. As a result, solution pH values of tests with the inflated vermiculites generally increased and then stabilized. Equilibrium pHs were generally established within 5 hrs. In addition, removal rates of inflated vermiculites were tested at the initial concentration of 3 mg/L. As a result, at equilibrium concentration, except for chromium (36.23%), Most of the heavy metals were effectively removed (96.08~98.54%). Finally, sorption data were correlated with both Langmuir and Freundlich isotherms. The Qmax obtained from Langmuir isotherm were determined to Pb $725.4mg\;kg^{-1}$, Cd $568.8mg\;kg^{-1}$, Zn $540.2mg\;kg^{-1}$, Cu $457.2mg\;kg^{-1}$ Cr $0.9mg\;kg^{-1}$ respectively. The results of the study indicate that inflated vermiculites can be properly used as an adsorbent for various heavy metals because of its outstanding removal rate.

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DEVELOPMENT OF ADSORBENT USING BYPRODUCTS FROM KOREAN MEDICINE FOR REMOVING HEAVY METALS

  • Kim, S.W.;Lim, J.L.
    • Environmental Engineering Research
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    • v.12 no.1
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    • pp.1-7
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    • 2007
  • Most of the herb residue producing from oriental medical clinics(OMC) and hospitals(OMH) is wasted in Korea. To develop of adsorbent for removing heavy metal from wastewater, the various pre-treatment methods of the herb residue were evaluated by potentiometric titration, Freundlich isotherm adsorption test and the kinetic adsorption test. The herb residue was pre-treated for increasing the adsorption capacity by cleaning with distilled water, 0.1 N HCl and 0.1 N NaOH and by heating at $370^{\circ}C$ for 30 min. It showed a typical weak acid-weak base titration curve and a short pH break like commercial activated carbon during photentiometric titration of pre-treated herb residue. The log-log plots in the Freundlich isotherm test were linear on the herb residue pre-treated with NaOH or HCl like commercial activated carbon. The adsorption capacity(qe) in the Freundlich isotherm test for $Cr^{6+}$ was 1.5 times higher in the pre-treated herb residue with HCl than in activated carbon. On the other hand the herb residue pre-treated with NaOH showed the good adsorption capacities for $Pb^{2+}$, $Cu^{2+}$ and $Cd^{2+}$ even though those adsorption capacities were lower than that of activated carbon. In kinetic test, most of heavy metals removed within the first 10 min of contact and then approached to equilibrium with increasing contact time. The removal rate of heavy metals increased with an increase of the amount of adsorbent. Likewise, the removal rates of heavy metals were higher in the herb residue pre-treated with NaOH than in that pre-treated with HCl. The adsorption preference of herb residues pre-treated with NaOH or HCl was $Pb^{2+}>Cu^{2+}$ or $Cd^{2+}>Cr^{6+}$ in the order. Conclusively, the herb residue can be used as an alternative adsorbent for the removal of heavy metals depending on pr-treatment methods.

An Analysis of Balassa-Samuelson Effect by Panel Cointegration Test (패널공적분검정을 통한 발라사-사무엘슨 효과 분석)

  • Choi, Yong-Jae
    • International Area Studies Review
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    • v.22 no.3
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    • pp.67-84
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    • 2018
  • The purpose of this paper is to investigate the Balassa-Samuelson effect that real exchange rate could deviate from its long-run equilibrium. To analyze this effect, I estimated the long-run relationship between real exchange and productivity using the dynamic panel ordinary least square(DOLS) and panel error correction model(ECM) after conducting the unit root and cointegration test. The results show that all variables except for the real exchange rate have the unit root. Then I conducted the cointegration test to find out whether there exist the stable long-run relationships. The results show that the variables are cointegrated and significant statistically. The DOLS and ECM methods are used to estimate the coefficient of the cointegrated variables. The major finding are that the estimates are statistically significant and that they show the same sign as the economic theory predicts.