• Title/Summary/Keyword: Environmental tests

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Study of the compression index for Busan and Inchon clays (부산점토와 인천점토의 압축지수 분석)

  • Hong, Sung-Jin;Choi, Yung-Min;Lee, Joo-Hyung;Lee, Moo-Joo;Lee, Woo-Jin
    • Proceedings of the Korean Geotechical Society Conference
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    • 2010.03a
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    • pp.1200-1205
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    • 2010
  • The compression index is one of the geotechnical properties which represent the compressibility of clay. The compression index are generally obtained from consolidation tests, otherwise it has been predicted by soil properties due to the efficiency time and cost. In this study, consolidation tests result for Busan and Inchon clays are analyzed to suggest the correlations between the compression index and soil properties. It is found that the compression index is well correlated with the void ratio and natural water contents. The prediction errors, which is difference of compression indices between measured from consolidation test and predicted by liquid limits, decrease with ${\Delta}e_0/e_L$.

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Dynamic Capabilities, Environmental Dynamism and Small and Medium Enterprises' Internationalization Level

  • ALI, Hazem;HAO, Yunhong;AIJUAN, Chen
    • The Journal of Asian Finance, Economics and Business
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    • v.7 no.9
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    • pp.527-536
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    • 2020
  • International business research presents a broad consensus on the importance of dynamic capabilities in the internationalization of SMEs. However, there is a lack of research on assessing the impact of dynamic capabilities and the level of SMEs' internationalization operating in a turbulent and dynamic business environment. This study examines the impact of environmental dynamism and three sets of dynamic capabilities, namely, sensing, seizing, and reconfiguring capabilities on internationalized SMEs' geographic scope. In addition, this research examines the association between internationalized SMEs' characteristics: SME's age, size, and SME owner/manager's international experience and SMEs' geographic scope. This study used a quantitative research and employed survey questionnaires to collect data from 305 internationalized Malaysian manufacturing SMEs. Anova tests and Chi Square tests were employed to analyze data collected from respondents using SPSS. Research findings revealed that environmental dynamism and dynamic capabilities have a significant impact on internationalized SMEs' geographic scope, however, none of the internationalized SMEs' characteristics had a significant relationship with their geographic scope. The result of this research suggest internationalized SMEs owner/managers need to possess sensing, seizing and reconfiguring capabilities, and monitor business environmental dynamism to increase their geographic scope. This paper ends with drawing a set of concluding remarks and recommendations.

Probabilistic and spectral modelling of dynamic wind effects of quayside container cranes

  • Su, Ning;Peng, Shitao;Hong, Ningning;Wu, Xiaotong;Chen, Yunyue
    • Wind and Structures
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    • v.30 no.4
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    • pp.405-421
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    • 2020
  • Quayside container cranes are important delivery machineries located in the most frontiers of container terminals, where strong wind attacks happen occasionally. Since the previous researches on quayside container cranes mainly focused on the mean wind load and static response characteristics, the fluctuating wind load and dynamic response characteristics require further investigations. In the present study, the aerodynamic wind loads on quayside container cranes were obtained from wind tunnel tests. The probabilistic and spectral models of the fluctuating aerodynamic loads were established. Then the joint probabilistic distributions of dynamic wind-induced responses were derived theoretically based on a series of Gaussian and independent assumption of resonant components. Finally, the results were validated by time domain analysis using wind tunnel data. It is concluded that the assumptions are acceptable. And the presented approach can estimate peak dynamic sliding force, overturning moments and leg uplifts of quayside container cranes effectively and efficiently.

A Evaluation of Environmental Resistance for Bio-Polymer Concretes (바이오 폴리머 콘크리트의 환경 저항성 평가 연구)

  • Kim, Je Won;Kim, Tae Woo;Park, Hee Mun;Kim, Bu Il
    • International Journal of Highway Engineering
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    • v.15 no.5
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    • pp.75-79
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    • 2013
  • PURPOSES : The objective of this study is to evaluate the environmental resistance of bio-polymer concrete for use of pavement materials developed for reducing the carbon-dioxide. METHODS : The compression, tension, and bending strength tests were conducted on the bio-polymer concrete specimens with and without environmental conditioning. The specimens were conditioned using the freezing-thaw and accelerated weathering process for long period of time. To assess the resistance against chloride, the chloride ion penetration resistance tests were carried out on the bio-polymer concrete specimens. RESULTS : Test results show that the maximum difference in strength between specimens with and without conditioning is about 2.6MPa indicating that the effect of environmental conditioning on specimen strength is negligible. Based on the chloride ion penetration resistance test, the penetration quantity of electric charge of the specimens is zero and there is no ion penetration within the bio-polymer concrete. CONCLUSIONS : It is found from this study that there is slight change in strength of bio-polymer concretes before and after environmental conditioning process and no chloride ion penetration observed in these specimens. Therefore, the developed bio-polymer concretes can be applied effectively as pavement materials due to the small change of physical properties with environment change.

Economic Growth, Financial Development, Transportation Capacity, and Environmental Degradation: Empirical Evidence from Vietnam

  • NGUYEN, Van Chien;VU, Duc Binh;NGUYEN, Thi Hoang Yen;PHAM, Cong Do;HUYNH, Tuyet Ngan
    • The Journal of Asian Finance, Economics and Business
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    • v.8 no.4
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    • pp.93-104
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    • 2021
  • In recent years, there has been a substantial theoretical and empirical study on the role that financial market development has significantly played in promoting economic growth and development in the world. The development of an economy requires the financial industry to be developed. In the context of rapid economic development, global warming has become a serious problem with issues such as rising average temperatures, climate change, rising sea level, and increasing carbon dioxide emissions. This study aims to examine the influence of economic growth, financial development, transportation capacity, and environmental degradation. Using time-series data from 1986 to 2019 and environmental degradation being measured by CO2 emissions, the study employs a quantity of ample unit root tests, the structural break unit root tests, Autoregressive Distributed Lag (ARDL), and cointegration bounds test. The results show that there is a significant long-term cointegration among study variables. Empirical findings also indicate that an increase in per capita GDP and financial development worsens environmental quality whereas transportation capacity and foreign investment can improve environmental quality.

Acute and Chronic Toxicity of heavy Metals to Daphnia magna (물벼룩(Daphnia magna)에 대한 중금속의 급성 및 만성 독성)

  • Jeong, Jae-Won;Cha, Mi-Seon;Jo, Sun-Ja;Lee, Sang-Jun
    • Journal of Environmental Science International
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    • v.10 no.4
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    • pp.293-298
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    • 2001
  • The toxicity values heavy metals were evaluated by immobilization and chronic reproduction impairment tests, using Daphnia magna. Acute tests were evaluated by the inhibition of their mobilization after 24hrs without food addition. The tests of reproductive impairment were investigated for 21 days by food addition and exchange or water. The effect of each concentration was assessed by Probit analysis and t-test. The results obtained from this study were as follows : 1) The change of pH and DO was not significant in the acute tests, while, in the reproductive tests, pH was increased by 0.3~1.4 and DO also increased. 2) The $E_iC_{50}$ values of immobilization to Daphnia magna in artificial fresh water were $0.030mg/{\ell}(Cu),\;0.054mg/{\ell}(Cd),\;0.12mg/{\ell};(Cr),\;0.74mg/{\ell}(Pb),\;3.4mg/ {\ell}(As)$ and the $NOE_iC$ values were $0.010mg/{\ell}(Cu),\;0.018mg/{\ell}(Cd),\;0.010mg/{\ell}(Cr),\;0.10mg/{\ell}(Pb),\;and\;$1.8mg/{\ell}(As)$. 3) The $E_rC_{50}$ values of reproductive impairment to Daphnia magna were $13.8\mu\textrm{g}/{\ell}(Cu),\;2.9\mu\textrm{g}/{\ell}(Cd),\;15.5\mu\textrm{g}/{\ell}(Cr),\;61.7\mu\textrm{g}/{\ell}(Pb),\;759\mu\textrm{g}/{\ell}(As)$, and $NOE_rC$ values were $0.95\mu\textrm{g}/{\ell}(Cu),\;$0.54\mu\textrm{g}/{\ell}(Cd),\;1.2\mu\textrm{g}/{\ell}(Cd),\;$7.4\mu\textrm{g}/{\ell}(Pb),\;110mu\textrm{g}/{\ell}(As)$. The results of tests using OECD artificial culture water were more sensitive than natural water for culturing. The presented data show that an artificial culture water is suitable in the experiment of bioassay for assessing the toxicity of marterials.

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Deformation Characteristics of the Pressurized Grouting Soil Nailing Systems from the Field Pull-out Tests (현장인발시험을 통한 가압 그라우팅 쏘일네일의 변형특성)

  • Chun, Byungsik;Park, Joosuck;Park, Sisam;Jung, Jongju;Kong, Jinyoung
    • Journal of the Korean GEO-environmental Society
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    • v.9 no.2
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    • pp.61-65
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    • 2008
  • In this study, a newly modified soil nailing technology named as the PGSN (Pressurized Grouting Soil Nailing) system is proposed. Effects of various factors related to the design of the pressurized grouting soil nailing system, such as the length of re-bars and type of reinforcement materials, were examined throughout a series of the displacement-controlled field pull-out tests. 9 displacement-controlled field pull-out tests were performed and the ratio of injected grout volume to grout hole volume were also evaluated based on the measurements. In addition, short-term characteristics of pull-out deformations of the newly proposed PGSN system were analyzed and compared with those of the ordinary soil nailing system by carrying out field pull-out tests. The test results were shown that the displacements of pressurized grouting soil nailing system were decreased 30~36% in comparison with using gravity grouting soil nailing system by the pressurized effect. The displacements of steel tube were diminished 31~32% comparison with using deformed bar by the reinforcement type change from the field pull-out tests.

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Future of Toxicology and Role of Asian Chemical Safety Network

  • Kaminuma, Tsuguchika
    • Toxicological Research
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    • v.17
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    • pp.241-249
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    • 2001
  • Toxicology is under challenge from several new trends in science and technology, namely computer, the Internet, genome projects, genomic technologies, and combinatorial chemistry. These new trends will drastically change research style of toxicology. In addition to conventional uni cellular tests and animal tests using rodents, computer simulation, DNA chips (microarrays), in vivo tests using simple model organisms such as nematodesor flies become important routine screening tests. How to arrange these tests in tiers will become a new problem. Endocrine disruptors hypothesis is a good example for this kind of futuristic approach. Computer, particularly the Internet, is also enabling toxicologists and regulatory experts to collaborate more closely. The IPCS (International Program for Chemical Safety) which is ajoint project of WHO, ILO and UNEP, is a well-known international collaborative research for chemical risk assessments. The GINC project of IPCS is an effort to utilize the Internet for such collaborations. Some efforts were also made to establish regional collaboration network in East Asia under this project.

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Effect of Airborne Organic Vapor Concentration Levels on the Adsorption Capacity of Charcoal in the Cartridges of Air Purifying Respirators (공기 중 유기용제 농도수준이 방독마스크 정화통의 활성탄 흡착용량에 미치는 영향)

  • Park, Doo-Yong
    • Journal of Environmental Health Sciences
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    • v.37 no.1
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    • pp.50-56
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    • 2011
  • The adsorption capacity of charcoal is a function of the airborne concentration of the target chemical. To evaluate the adsorption capacity of charcoal packed in the cartridges of air purifying respirators, breakthrough tests were conducted with carbon tetrachloride for three commercial cartridges (3M models #7251, #6000 and AX) at 25, 50, 100, 250 and 500 ppm. Adsorption capacities were calculated using a mass transfer balance equation derived from the curve fitting to the breakthrough curves obtained experimentally. Carbon micropore volumes were estimated by iteration to fit the Dubinin/Radushkevich (D/R) adsorption isotherm. They were 0.6566, 0.5727 and 0.3087 g/cc for #7251, #6000 and the AX cartridge, respectively. Above 100 ppm (at high challenge concentrations), #7251 and #6000 showed higher adsorption capacities. However, as the challenge concentration decreased, the adsorption capacities of #7251 and #6000 sharply dropped. On the other hand, the adsorption capacity of the AX cartridge showed little change with the decrease of the challenge concentration. Thus, the AX showed a higher adsorption capacity than #7251 and #6000 at the 5-50 ppm level. It is concluded that service-life tests of cartridges and adsorption capacity tests of charcoal should be conducted at challenge concentration levels reflecting actual working environmental conditions. Alternatively, it is recommended to use the D/R adsorption isotherm to extrapolate adsorption capacity at low concentration levels from the high concentration levels at which breakthrough tests are conducted, at a minimum of two different concentration levels.

Pullout Resistance Increase in Soil-Nailing with Pressurized Grouting: Verification of Theoretical Solution (압력식 쏘일네일링의 인발저항력 증가: 이론적 검증)

  • Seo, Hyung-Joon;Park, Sung-Won;Jeong, Kyeong-Han;Choi, Hang-Seok;Lee, In-Mo
    • Proceedings of the Korean Geotechical Society Conference
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    • 2009.03a
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    • pp.419-433
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    • 2009
  • Pressure grouting is a common technique in geotechnical engineering to increase the stiffness and strength of the ground mass and to fill boreholes or void space in a tunnel lining and so on. Recently, the pressure grouting has been applied to a soil-nailing system which is widely used to improve slope stability. The soil-nailing design has been empirically performed in most geotechnical applications because the interaction between pressurized grouting paste and the adjacent ground mass is complicated and difficult to analyze. The purpose of this study is to analyze the increase of pullout resistance induced by pressurized grouting with the aid of performing laboratory model tests and field tests. In this paper, two main causes of pullout resistance increases induced by pressurized grouting were verified: the increase of residual stress; and the increase of coefficient of pullout friction. From the laboratory tests, it was found that residual stress in borehole increases by pressurized grouting and dilatancy angle could be estimated by cavity expansion theory using the measured wall displacements. From the field test results, the pullout resistance of soil-nailing with pressurized grouting was found to be 10% larger than that of soil-nailing with gravitational grouting, mainly caused by mean normal stress increase and dilatancy effect. So, the pullout resistance could be estimated by considering these two effects. The radial displacement increases with dilatancy angle increase and the dilatancy angle decreases with injection pressure increase. The measured pullout resistance obtained from field tests is in good agreement with the estimated one from the cavity expansion theory.

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