• 제목/요약/키워드: Impact pressure

검색결과 1,548건 처리시간 0.03초

해수 환경에서 슈퍼 오스테나이트 스테인리스강의 전기화학적 거동에 미치는 캐비테이션 진폭의 영향 (Effect of Cavitation Amplitude on the Electrochemical Behavior of Super Austenitic Stainless Steels in Seawater Environment)

  • 허호성;김성종
    • Corrosion Science and Technology
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    • 제21권2호
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    • pp.138-146
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    • 2022
  • The cavitation and potentiodynamic polarization experiments were conducted simultaneously to investigate the effect of cavitation amplitude on the super austenitic stainless steel (UNS N08367) electrochemical behavior in seawater. The results of the potentiodynamic polarization experiment under cavitation condition showed that the corrosion current density increased with cavitation amplitude increase. Above oxygen evolution potential, the current density in a static condition was the largest because the anodic dissolution reaction by intergranular corrosion was promoted. In the static condition, intergranular corrosion was mainly observed. However, damage caused by erosion was observed in the cavitation environment. The micro-jet generated by cavity collapse destroyed the corrosion product and promoted the repassivation. So, weight loss occurred the most in static conditions. After the experiment, wave patterns were formed on the surface due to the compressive residual stress caused by the impact pressure of the cavity. Surface hardness was improved by the water cavitation peening effect, and the hardness value was the highest at 30 ㎛ amplitude. UNS N08367 with excellent mechanical performance due to its high hardness showed that cavitation inhibited corrosion damage.

Impact of CO2 Emissions, Exchange Rate Regimes, and Political Stability on Currency Crises: Evidence from South Asian Countries

  • ULLLAH, Zia;FEN, Tan Xiao;TUNIO, Fayaz Hussain;ULLAH, Imran
    • The Journal of Asian Finance, Economics and Business
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    • 제9권2호
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    • pp.29-36
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    • 2022
  • This study uses the panel probit model to investigate and evaluate the relationship between exchange rate regimes, political stability, and carbon dioxide during currency crises. To understand currency crisis times, we study a panel dataset of seven South Asian nations that contain annual observations from 1996 to 2020. Furthermore, we created the EMPI exchange market pressure indicator to detect crises. Our results strongly suggested that fixed exchange rate is negatively associated with currency crises, with good regulatory quality and better effective governments. Simultaneously, the floating exchange rate is positively related to the currency crises in those countries where the rule of law has less adequately flowed. However, CO2, exports, and interest rates are buoyantly associated with crises. The floating exchange rate, the rule of law, exports, and interest rate are associated positively and contribute more prone to the crisis episodes. Negatively associated variables contributed less amid crises episodes: fixed exchange rate regime, government effectiveness, and regulatory quality. Meanwhile, CO2 has a positive relationship with a currency crisis and contributes more likelihood to the probability of a currency crisis. Countries that adopted the fixed exchange rates with effective governments and regulatory quality faced more minor currency crises.

ICT-based Cooperative Model for Transparent and Sustainable Scholarly Publishing Ecosystem

  • Jung, Youngim;Seo, Tae-Sul
    • Journal of Contemporary Eastern Asia
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    • 제21권1호
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    • pp.53-71
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    • 2022
  • The overall purposes of this study are to identify actions taken to counter predatory publishing practices as well as to propose an ICT-based model to detect such practices. The need to raise quantitative performance metrics to support career goals has created immense pressure on researchers to publish in the literature as frequently as possible. This "publish or perish" syndrome appears to be fueling a rise in scholarly journals and conferences that provide quicker and easier routes to publication. However, such avenues sometimes involve questionable academic practices with important ethical ramifications. One notable example is the proliferation of predatory publishing, including predatory journals and fake conferences. The widening impact of such activities is beginning to prompt academic societies, publishers, and institutions to take measures. This paper discusses the issues on predatory publishing practices, and some of the actions taken by various stakeholders to address these practices. In order to build a transparent and sustainable scholarly publishing ecosystem, this study highlights multi-dimensional and specific solutions, including reforms to research ethics codes, research management rules, and legal protection from exploitative practices. This paper proposes an ICT-based cooperative model for monitoring of predatory publishers as a potential solution to create a sustainable and transparent infrastructure for a scholarly publication system guarding against misconduct in publishing practices.

식품기업의 ESG 경영활동이 기업성과에 미치는 영향 (Effects of ESG Management Activities of Food Companies on Corporate Performance)

  • 정서영;최규완
    • 한국프랜차이즈경영연구
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    • 제14권2호
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    • pp.19-30
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    • 2023
  • Purpose: Corporate management is under pressure to contribute to social values beyond profit-seeking, and interest in ESG (Environment, Social, Governance) is increasing worldwide. In the recent global climate change crisis and the COVID-19 pandemic, the importance of non-financial values such as ESG is increasing. Therefore, the purpose of this study is to prepare a strategy for future ESG management activities by analyzing the impact of it on corporate performance by food companies. Research design, data and methodology: ESG-related research trends, ESG activities, and corporate performance were analyzed. After that, a regression analysis was conducted to identify the relationship between ESG evaluation grade and corporate performance. Result: ESG management activities measured by ESG scores did not significantly affect the return on assets, one of the variables of corporate performance. However, as a result of setting the return on equity as a dependent variable, ESG management activities have a nonlinear relationship with corporate performance, and ESG management activities have a positive effect on corporate performance when investment in ESG management activities is reasonable. Conclusions: These results show that food companies should engage in an appropriate level of ESG management activities to improve corporate performance.

Meander Flume Outlet Sediment Scour Analysis of a Boxed Culvert

  • Thu Hien Thi Le;VanChienNguyen;DucHauLe
    • 한국수자원학회:학술대회논문집
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    • 한국수자원학회 2023년도 학술발표회
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    • pp.35-35
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    • 2023
  • The main reason for its instability is sediment scouring downstream of hydraulic structures. Both physical and numerical models have been used to investigate the influence of soil properties on scour hole geometry. Nevertheless, no research has been conducted on resistance parameters that affect sedimentation and erosion. In addition, auxiliary structures like wing walls, which are prevalent in many real-world applications, have rarely been studied for their impact on morphology. The hydraulic characteristics of steady flow through a boxed culvert are calibrated using a 3D Computational Fluid Dynamics model compared with experimental data in this study, which shows a good agreement between water depth, velocity, and pressure profiles. Test cases showed that 0.015 m grid cells had the lowest NRMSE and MAE values. It is also possible to quantify sediment scour numerically by testing roughness/d50 ratios (cs) and diversion walls at a meander flume outlet. According to the findings, cs = 2.5 indicates a close agreement between numerical and analytical results of maximum scour depth after the culvert; four types of wing walls influence geometrical deformation of the meander flume outlet, resulting in erosion at the concave bank and deposition at the convex bank; two short headwalls are the most appropriate solution for accounting for small changes in morphology. A numerical model can be used to estimate sediment scour at the meander exit channel of hydraulic structures based on the roughness parameter of soil material and headwall type.

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The behaviour of a strip footing resting on geosynthetics-reinforced slopes

  • Hamed Yazdani;Mehdi Ashtiani
    • Geomechanics and Engineering
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    • 제34권6호
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    • pp.623-636
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    • 2023
  • This study utilized small-scale physical model tests to investigate the impact of different types of geosynthetics, including geocell, planar geotextile, and wraparound geotextile, on the behaviour of strip footings placed on 0.8 m thick soil fills and backfills with a slope angle of 70°. Bearing capacity and settlement of the footing and failure mechanisms are discussed and evaluated. The results revealed that the bearing capacity of footings situated on both unreinforced and reinforced slopes increased with a greater embedment depth of the footing. For settlement ratios below 4%, the geocell reinforcement exhibited significantly higher stiffness, carrying greater loads and experiencing less settlement compared to the planar and wraparound geotextile reinforcements. However, the performance of geocell reinforcement was influenced by the number and length of the geocell layers. Increasing the geocell back length ratio from 0.44 to 0.84 significantly improved the bearing capacity of the footing located at the crest of the reinforced slope. Adequate reinforcement length, particularly for geocell, enhanced the bearing pressure of the footing and increased the stiffness of the slope, resulting in reduced deflections. Increasing the length of reinforcement also led to improved performance of the footing located on wraparound geotextile reinforced slopes. In all reinforcement cases, reducing the vertical spacing between reinforcement layers from 100 mm to 75 mm allowed the slope to withstand much greater loads.

Investigating the dynamic response of deep soil mixing and gravel drain columns in the liquefiable layer with different thickness

  • Gholi Asadzadeh Khoshemehr;Hadi Bahadori
    • Geomechanics and Engineering
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    • 제34권6호
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    • pp.665-681
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    • 2023
  • Liquefaction is one of the most devastating geotechnical phenomena that severely damage vital structures and lifelines. Before constructing structures on problematic ground, it is necessary to improve the site and solve the geotechnical problem. Among ground improvement methods dealing with liquefaction, gravel drain (GD) columns and deep soil mixing (DSM) columns are popular. In this study, the results of a series of seismic experiments in a 1g environment on a structure located over liquefiable ground with different thicknesses reinforced with GD and DSM techniques were presented. The dynamic response of the reinforced ground system was investigated based on the parameters of subsidence rate, excess pore water pressure ratio, and maximum acceleration. The time history of the input acceleration was applied harmonically with an acceleration range of 0.2g and at frequencies of 1, 2, and 3 Hz. The results show that the thickness of the liquefiable layer and the frequency of the input motion have a significant impact on the effectiveness of the improvement method and all responses. Among the two techniques used, DSM in thick liquefied layers was much more efficient than GD in controlling the subsidence and rupture of the soil under the foundation. Maximum settlement values, settlement rate, and foundation rotation in the thicker liquefied layer at the 1-Hz input frequency were higher than at other frequencies. At low thicknesses, the dynamic behavior of the GD was closer to that of the DSM.

A Direct Utility Model with Dynamic Constraint

  • Kim, Byungyeon;Satomura, Takuya;Kim, Jaehwan
    • Asia Marketing Journal
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    • 제18권4호
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    • pp.125-138
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    • 2017
  • The goal of the study is to understand how consumers' constraint as opposed to utility structure gives rise to final decision when consumers purchase more than one variant of product at a time, i.e., horizontal variety seeking or multiple-discreteness. Purchase and consumption decision not only produces utility but also involves some sort of cognitive pressure. Past consumption or last purchase is likely to be linked to this burden we face such as concern for obesity, risk of harm, and guilt for mischief. In this research, the existence and the role of dynamic constraint are investigated through a microeconomic utility model with multiple dynamic constraint. The model is applied to the salty snacks data collected from field study where burden for spiciness serves as a constraint. The results are compared to the conventional multiple discreteness choice models of static constraints, and policy implications on price discounts is explored. The major findings are that first, one would underestimate the level of consumer preference for product offerings when ignoring the carry-over of the concern from the past consumption, and second, the impact of price promotion on demand would be properly evaluated when the model allows for the role of constraint as both multiple and dynamic. The current study is different from the existing studies in two ways. First, it captures the effect of 'mental constraint' on demand in formal economic model. Second, unlike the state dependence well documented in the literature, the study proposes the notion of state dependence in different way, via constraint rather than utility.

Service Quality in the Distribution of Consumer Attitudes, Word of Mouth, and Private University Selection Decisions

  • PURWANTORO;Nurul Zarirah NIZAM
    • 유통과학연구
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    • 제21권10호
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    • pp.51-61
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    • 2023
  • Purpose: Research focuses on private universities' professional education in a competitive educational environment. Due to increased competition in the higher education industry, private universities are under pressure to improve their marketing strategies and better understand their prospective students. This study intends to investigate how information sources are used and modified by Indonesian university students when making decisions. Research design, data and methodology: This research is a case study in Riau province, which includes active university students registered in the government database. Data was collected using a questionnaire distributed via Google Forms to students at a private university, and 164 students completed the questionnaire. Results: The results show that the influence of technical quality, functional quality, and image cannot affect word of mouth, and technical quality cannot affect consumer attitudes. The results show that the distribution of high service quality and high image will encourage people to share their experiences by word of mouth to build evaluation attachment in college selection. and found that a good campus image has no direct impact on word of mouth. The spread of an excellent campus image only attracts students to evaluate it. The more talk about the distribution of service quality, the higher the decision to choose the service.

급속 충전에서 탱크 내부의 수소 온도 변화에 관한 이론 연구 (A Theoretical Study on the Hydrogen Temperature Evolution Inside the Tank under Fast Filling Process)

  • 이길초;이길강;허항;최병철;권정태
    • 한국수소및신에너지학회논문집
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    • 제34권6호
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    • pp.608-614
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    • 2023
  • The fast filling process of high-pressure hydrogen has an important impact on the filling efficiency and safety. In this paper, a specific study is carried out on the thermophysical phenomena during the fast filling process. Starting from the gas state equation of hydrogen, the change law of the hydrogen storage temperature is obtained, and then the temperature rise prediction is constructed. The model can clarify the relationship between the filling parameters and the temperature rise during the fast filling process, thereby revealing the flow and heat transfer laws of the fast charging process. To improve the theoretical research basis for the evaluation of vehicle-mounted hydrogen fast charging capacity, temperature prediction and optimization of hydrogenation methods.