• Safety and Health at Work
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• 제7권2호
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• pp.130-137
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• 2016

At a brewery, the base plate-to-shell weld seam of a $90-m^3$ vertical cylindrical steel tank failed catastrophically. The 4 ton tank "took off" like a rocket leaving its contents behind, and landed on a van, crushing it. The top of the tank reached a height of 30 m. The internal overpressure responsible for the failure was an estimated 60 kPa. A rupture disc rated at < 50 kPa provided overpressure protection and thus prevented the tank from being covered by the European Pressure Equipment Directive. This safeguard failed and it was later discovered that the rupture disc had been installed upside down. The organizational root cause of this incident may be a fundamental lack of appreciation of the hazards of large volumes of low-pressure compressed air or gas. A contributing factor may be that the standard piping and instrumentation diagram (P&ID) symbol for a rupture disc may confuse and lead to incorrect installation. Compressed air systems are ubiquitous. The medium is not toxic or flammable. Such systems however, when operated at "slight overpressure" can store a great deal of energy and thus constitute a hazard that ought to be addressed by safety managers.

• 한국산업융합학회 논문집
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• 제24권4_2호
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• pp.467-474
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• 2021

The renewable energy is known as eco-friendly energy to reduce the use of fossil fuel and decrease the environmental pollution due to exhaust gas. Targets of solar collector in domestic are usually acquisitions of hot water and hot air. System of air-heating collector is one of the technologies for obtaining hot air in cases of especially heating room and drying agricultural product. The purpose of this study is to investigate the characteristics of thermal flow such as relative pressure, velocity, outlet temperature and buoyancy effect in air-heating collector using solar heat. The flow field of air-heating collector was simulated using ANSYS-CFX program and the behaviour of hot air was evaluated with SST turbulence model. As the results, The streamline in air-heating collector showed several circular shapes in case of condition of buoyancy. Temperature difference in cross section of outlet of air-heating collector did not almost show in cases of buoyancy and small inlet velocity. Furthermore merit of air-heating collector was not observed in cases of inlet velocities. Even though it was useful to select condition of buoyancy for obtaining high temperature, however, it was confirmed that the trade off between high temperature of room and rapid injection of hot air to room could be needed through this numerical analysis.

• 산업기술연구
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• 제42권1호
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• pp.7-12
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• 2022

High nickel layered oxide cathodes are gaining increasing attention for lithium-ion batteries due to their higher energy density and lower cost compared to LiCoO₂. However, they suffer from the formation of residual lithium on the surface in the form of LiOH and Li₂CO₃ on exposure to ambient air. The residual lithium causes notorious issues, such as slurry gelation during electrode preparation and gas evolution during cell cycling. In this review, we investigate the residual lithium issues through its impact on cathode slurry instability based on deformed polyvinylidene fluoride (PVdF) as well as its formation and reduction mechanism in terms of inherently off-stoichiometric synthesis of high nickel cathodes. Additionally, new analysis method with anhydrous methanol was introduced to exclude Li⁺/H⁺ exchange effect during sample preparation with distilled water. We hope that this review would contribute to encouraging the academic efforts to consider practical aspects and mitigation in global high-energy-density lithium-ion battery manufacturers.

• Tribology and Lubricants
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• 제38권5호
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• pp.222-226
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• 2022

Between diaphragms made of stainless steel (SUS), which is the main component of a hydrogen gas compressor, micro-slip occurs owing to repeated bending, resulting in scratches on the surface. The surface scratch of the compressor part is a problem with airtightness, which reduces the efficiency of the compressor; in severe cases, damage is a possibility. In this study, the changes in friction and wear characteristics due to the surface polishing of SUS and carbon-based solid lubricant films (graphene and CNT) were analyzed. Bare SUS, polished SUS, graphene film, and CNT film specimens were prepared. The surface roughness of the SUS was significantly reduced by surface polishing but increased by carbon-based solid lubricating films. In contrast, the friction coefficient maintained a similar value after surface polishing but was significantly reduced by the carbon-based solid lubricant films. In particular, the graphene film exhibited the lowest initial friction coefficient, while the CNT film exhibited the lowest overall average friction coefficient. Regarding the wear rate, polished SUS exhibited the lowest value, but the surface condition of the wear track showed that the carbon-based solid lubricating films were relatively less damaged. Although the wear rate measured was largely attributed to the solid lubricating film peeling off, the SUS surface under the film was considered protected.

• Strategy21
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• 통권30호
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• pp.200-235
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• 2012

Over the past few years, due to the climate change of the earth, the Arctic's sea ice cover is undergoing a historic transformation - thinning, extent reduction in all seasons, and mitigation in the area of multi-year ice in the central Arctic Ocean. These changes allow for increases in maritime access throughout the Arctic Ocean and for potential longer seasons of navigation and possibly transarctic voyage in the summer. These changes also allow more exploration for oil, gas, and other minerals. The Arctic is now an archetype of the complex, multi-dimensional global problems of the twenty-first century. Military security, environmental security, and economic security interact. The potentially enormous economic stakes, sufficient to change the strategic balance among the states of the region, set off competitive pressures for national advantage. Korea, which is heavily dependent upon the sea lane in terms of transportation of its exports and imports, is very much interested in the Arctic sea routes. Korea believes that the Artic sea route, particularly the Northern Sea Route (NSR), could serve as a new useful sea lane, which will enable shorter times between East Asia and Europe, thus resulting in substantial cost saving for ship operators. In addition to shipping, Korea is interested in other Arctic-related maritime industries. Korea, as a leading shipbuilder in the global market, is interested in building ice breakers, drill ships, and other vessels which can contribute to safe operation in Arctic resource development and exploration. Korea, as one of the future stakeholders in Arctic maritime activities, should be ready to foster international cooperation in the region.

• Advances in aircraft and spacecraft science
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• 제10권3호
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• pp.245-256
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• 2023

In order to improve aerodynamic performance of multi-stage axial flow turbines used in aircraft engines, a one-dimensional aerodynamic design and optimization framework is constructed. In the method, flow path is generated by solving mass continuation and energy conservation with loss computed by the Craig & Cox model; Also real gas properties has been taken into consideration. To obtain an optimal result, a multi-objective genetic algorithm is used to optimize the efficiencies and determine values of various design variables; Final design can be selected from obtained Pareto optimal solution sets. A three-stage axial turbine is used to verify the effectiveness of the developed optimization framework, and designs are checked by three-dimensional CFD simulation. Results show that the aerodynamic performance of the optimized turbine has been significantly improved at design point, with the total-to-total efficiency increased by 1.17% and the total-to-static efficiency increased by 1.48%. As for the off-design performance, the optimized one is improved at all working points except those at small mass flow.

• 국제학술발표논문집
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• The 4th International Conference on Construction Engineering and Project Management Organized by the University of New South Wales
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• pp.311-317
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• 2011

There is a growing concern in reducing greenhouse gas emissions all over the world. The U.K. has set 34% target reduction of emission before 2020 and 80% before 2050 compared to 1990 recently in Post Copenhagen Report on Climate Change. In practise, Life Cycle Cost (LCC) and Life Cycle Assessment (LCA) tools have been introduced to construction industry in order to achieve this such as. However, there is clear a disconnection between costs and environmental impacts over the life cycle of a built asset when using these two tools. Besides, the changes in Information and Communication Technologies (ICTs) lead to a change in the way information is represented, in particular, information is being fed more easily and distributed more quickly to different stakeholders by the use of tool such as the Building Information Modelling (BIM), with little consideration on incorporating LCC and LCA and their maximised usage within the BIM environment. The aim of this paper is to propose the development of a model-based LCC and LCA tool in order to provide sustainable building design decisions for clients, architects and quantity surveyors, by then an optimal investment decision can be made by studying the trade-off between costs and environmental impacts. An application framework is also proposed finally as the future work that shows how the proposed model can be incorporated into the BIM environment in practise.

• Nuclear Engineering and Technology
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• 제56권4호
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• pp.1234-1243
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• 2024

The pressing need to mitigate greenhouse gas emissions has stimulated a renewed interest in nuclear energy worldwide. However, while numerous countries have shown interest in nuclear power over the course of history, many of them have not continued their pursuit and chosen to defer or abandon their peaceful nuclear power projects. Scrapping a national nuclear power program after making initial efforts implies significant challenges in such a course or a waste of national resources. Therefore, this study aims to identify the crucial factors that influence a country's decision to terminate or hold off its peaceful nuclear power programs. Our empirical analyses demonstrate that major nuclear accidents and leadership changes are significant factors that lead countries to terminate or defer their nuclear power programs. Additionally, we highlight that domestic politics (democracy), lack of military alliance with major nuclear suppliers, low electricity demand, and national energy security environments (energy import, crude oil price) can hamper a country's possibility of regaining interest in a nuclear power program after it has been scrapped, suspended, or deferred. The findings of this study have significant implications for policymakers and stakeholders in the energy sector as they strive to balance the competing demands of energy security, and environmental sustainability.

• 한국대기환경학회지
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• 제33권6호
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• pp.570-582
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• 2017

In recent years, national and local government's air quality management and climate change adaptation policy has been significantly strengthened. The measures in the two policies may be in a relationship of trade-off or synergy to each other. Greenhouse gases and air pollutants are mostly emitted from the same sources of using considerable amounts of fossil fuels. Co-benefits, in which either measure has a positive effect on the other, may be maximized by reducing the social costs and by consolidating the objectives of the various policies. In this study, the co-benefits were examined by empirically analyzing the effects of air pollutants and greenhouse gas emission reduction, social cost, and cost effectiveness between the two policies. Of the total 80 projects, the next 12 projects generated co-benefits. They are 1) extend restriction area of solid fuel use, 2) expand subsidy of low-$NO_x$ burner, 3) supply hybrid-vehicles, 4) supply electric-vehicles, 5) supply hydrogen fuel cell vehicles, 6) engine retrofit, 7) scrappage of old car, 8) low emission zone, 9) transportation demand management, 10) supply land-based electric of ship, 11) switching anthracite to clean fuel in private sector, 12) expand regional combined-energy supply. The benefits of air pollutants and greenhouse gas-related measures were an annual average of KRW 2,705.4 billion. The social benefits of the transportation demand management were the highest at an annual average of KRW 890.7 billion, and followed by scrappage of old cars and expand regional combined-energy supply. When the social benefits and the annual investment budgets are compared, the cost effectiveness ratio is estimated to be about 3.8. Overall, the reduction of air pollutants caused by the air quality management policy of Gyeonggi-do resulted in an annual average of KRW 4,790.2 billion. In the point sources management sector, the added value of $CO_2$ reduction increased by 4.8% to KRW 1,062.8 billion, while the mobile sources management sector increased by 3.6% to KRW 3,414.1 billion. If social benefits from $CO_2$ reduction are added, the annual average will increase by 7.2% to KRW 5,135.4 billion. The urban and energy management sectors have shown that social benefits increase more than twice as much as the benefits of $CO_2$ reduction. This result implies that more intensive promotion of these measures are needed. This study has significance in that it presents the results of the empirical analysis of the co-benefits generated between the similar policies in the air quality management and the climate change policy which are currently being promoted in Gyeonggi-do. This study suggested that the method of analyzing the policy effect among the main policies in the climate atmospheric policy is established and the effectiveness and priority of the major policies can be evaluated through the policy correlation analysis based on the co-benefits. It is expected that it could be a basis for evaluation the efficiency of the climate change adaptation and air quality management policies implemented by the national and local governments in the future.

• 무역상무연구
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• 제54권
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• pp.145-166
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• 2012

This article examines the limitations of the choice of law caused by Internationally Mandatory Rules in Entering into the Turn-Key Contracts. In June 2007, Clough Engineering, a corporation based in Western Australia, approached the Federal Court of Australia seeking injunctive relief and leave to commence proceedings against an entity located outside Australia, the Oil & Natural Gas Corp of India (ONGC). Clough had contracted with ONGC to provide a range of services in relation to the construction of gas and oil wells off the coast of India. The contract was governed by Indian law, and included a clause by which the parties agreed to submit their disputes to arbitration. Yet the Federal Court assumed jurisdiction over the dispute, principally because Clough had framed its claim as a plea for relief for contraventions of Australia's Trade Practices Act 1974. The result of this cases that it is possible for an arbitral tribunal to hear a claim made under the Trade Practices Act even if that claim arises "in connection with"a contract the proper law of which is not the law of Australia. However, in Transfield Philippines Inc v Pacific Hydro Ltd, the turnkey contract included a choice of law provision, selecting the law of the Philippines, and a clause providing that all disputes arising out of or in connection with the agreement were to be arbitrated under the ICC Rules, with the seat in Singapore. Hearings were in fact conducted in Melbourne, Australia, although all awards were published in Singapore. The result of this cases that it would not be appropriate for an Australian court to adjudicate claims for misrepresentation under Australian statutes dealing with misleading and deceptive conduct, once the arbitral tribunal had determined, applying appropriate choice of law rules, that such claims are governed by the law of the Philippines. To do so would lead to a multiplicity of proceedings, usurp the jurisdiction of the tribunal and deny the intention of the parties as expressed by them in the arbitration agreement. In short, the Internationally Mandatory Rules as an active part of public order create limitation of party autonomy in choice of law rules in a different way. The court is fully entitled to refuse to use those rules of law applicable on the contract which are in the contradiction to the internationally mandatory rules of law of the forum. And the court may give an effect to those Internationally Mandatory Rules that form a part of a law of foreign country when deciding about applicability of certain rules of applicable law.