• Corrosion Science and Technology
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• v.18 no.5
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• pp.196-205
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• 2019

Surface modification techniques are known to improve SCC by adding large compressive residual stresses to metal surfaces. This surface modification technology is attracting attention because it is an economical and practical technology compared to the maintenance method of existing nuclear power plants. Surface modification techniques include laser, water jet and ultrasonic peening, pinning and ultrasonic Nano-crystal surface modification (UNSM). The focus of this study was on the effect of ultrasonic amplitude in UNSM treatment on the corrosion properties of Alloy 600. A microstructure analysis was conducted using an optical microscope (OM), scanning electron microscope (SEM) and electron backscattering diffraction (EBSD). A cyclic polarization test and AC-impedance measurement were both used to analyze the corrosion properties. UNSM treatment influences the corrosion resistance of Alloy 600 depending on its amplitude. Below the critical amplitude value, the pitting corrosion properties are improved by grain refinement and compressive residual stress, but above the critical amplitude value, crevices are formed by the formation of overlapped waves. These crevices act as corrosion initiators, reducing pitting corrosion resistance.

• Journal of Ceramic Processing Research
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• v.19 no.6
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• pp.509-513
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• 2018

This study uses fly ash for non-shrinkage grout in order to develop strength of grout and improve its durability. We grind fly ash to the extent of $7,000cm^2/g$ and use ground fly ash and raw fly ash respectively at the proportion of 10%, 20%, 30% instead of OPC and compare the results drawn on the condition of each proportion. As a mixed material of grout, EVA and water-reducing agent is added in order to prevent bleeding and improve segregation resistance, CSA is added with a view to preventing drying shrinkage and improving early strength property. In regard to flow and flow time test for analyzing and evaluating workability, it is revealed that grouts of all mix proportions except raw fly ash 30% mix proportion satisfy all performance criteria. With regard to length change rate, grout with no admixture shows the highest shrinkage rate, but the rate is 0.0005%, extremely insignificant rate. As material age increases, compressive strength of two grouts, that is to say ground fly ash 10% and 20%-used grouts, exceed that of grout with no admixture or show high-level compressive strength.

• International Journal of Advanced Culture Technology
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• v.9 no.1
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• pp.129-135
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• 2021

In this study, we built a mock-up of an indoor garden for private use and vertical gardens were installed on the walls of this indoor garden model. The purpose of this study is to examine the types of plants for best fit for growth and nurture in vertical garden and to identify the effects of indoor air quality improvement by these plants. As the result of the experiment, 22 species out of 32 species previously used for indoor garden was selected to be suitable for vertical gardens of a personal indoor garden. 10 species were found to be inappropriate for a personal indoor garden in terms of ornamental value, growth status and maintenance. The effect of plants on reducing CO2 has been proven by many studies. Also, through photosynthesis, plants combine CO2 with water and produce sugars and O2 (oxygen). Everyone accepts this fact. In nature, the production of oxygen is so important that without plants we would soon use it up and die. From the NASA Fact Sheet we know that air contains 20.95% O2 and 0.04% CO2. If you had enough plants in a room to use up all of the all of CO2 and convert it to oxygen, the oxygen levels would increase from 20.95% to 21%. This increase is difficult to detect and would have no effect on humans.

• International Journal of Computer Science & Network Security
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• v.22 no.1
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• pp.85-92
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• 2022

In this article, we look at the application of BIM (Building Information Modeling) in sustainable infrastructures. In response to global warming, energy shortages, and environmental degradation, people are trying to build eco-friendly, low-carbon cities and promote eco-friendly homes. A "green" building is the entire life cycle of a building that includes maximizing the conservation of resources (energy, water, land, and materials), protecting the environment, reducing pollution, providing people with healthy, comfortable, and efficient use of space, and establishing harmony between nature and architecture. In the field of ecological and sustainable buildings, BIM modeling can be integrated into buildings with analog energy, air flow analysis, and solar building ecosystems. Using BIM technologies, you can reduce the amount of waste and improve the quality of construction. These technologies create "visualization" of digital building models through multidimensional digital design solutions that provide" modeling and analysis "of Scientific Collaboration Platforms for designers, architects, utility engineers, developers, and even end users. Moreover, BIM helps them use three-dimensional digital models in project design and construction and operational management.

• Journal of the Korean Society of Industry Convergence
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• v.25 no.1
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• pp.131-139
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• 2022

The exchange of goods over the sea is a situation in which the amount of trade between countries is gradually increasing. In order to maintain the optimal operating condition, the ship maintains stability and optimal operating conditions by inserting or withdrawing ballast water from the ballast tank according to the loading condition of cargo capacity is also increasing. Control valves play an important role in controlling fluid flow in these pipes. When the flow rate is controlled using a control valve, problems such as cavitation, flashing, and suffocating flow may occur due to high differential pressure, and in particular, damage to valves and pipes due to cavitation is a major problem. Therefore, in this study, the cavitation phenomenon is reduced by installing orifices at the front and rear ends of the high differential pressure control butterfly valve to reduce the sudden pressure drop at the limiting part of the butterfly valve step by step. The flow coefficient according to the shape of the orifice, the degree of cavitation occurrence, and the correlation were analyzed using a CFD(Cumputational Fluid Dynamics), and an optimal orifice design for reducing cavitation is derived.

• Journal of The Korean Society of Grassland and Forage Science
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• v.42 no.2
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• pp.114-119
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• 2022

The objective of this study was to determine phosphorus effects on drought stress-induced oxidative stress in Kentucky bluegrass. Drought stress was induced by reducing of water to plants in pots. Two types of phosphorus were applied as potassium phosphate (P) or potassium phosphonate (PA). Application of phosphorus was efficient to ameliorate the adverse effects of drought. Osmotic potential, total chlorophyll and carotenoid content were significantly decreased by drought stress, but was relieved by P or PA application. Superoxide (O₂^•-) concentration was significantly increased more than 14-fold under drought-stressed plants, was accompanied with increase of hydrogen peroxide (H₂O₂) and lipid peroxidation (MDA). However, malondialdehyde (MDA) was much less in P or PA applied plants under drought stress condition. Activities of catalase (CAT), ascorbate peroxidase (APX) and guaiacol-peroxidase (GPX) were largely increased by drought stress and its increase rate was much higher in P or PA applied plants except APX. These results indicate that drought stress-induced oxidative stress is alleviated by P or PA application due to the increase of activities of antioxidant enzymes.

• Nuclear Engineering and Technology
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• v.53 no.5
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• pp.1491-1510
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• 2021

This work presents an illustration of Nagra's AMAC (Advanced Methodology for Activation Characterization) approach to the South Korean pressurized water reactor Kori-1 decommissioning. The results achieved are supported by the existing experience from the detailed AMAC applications to Swiss NPPs and are used not only for a demonstration of the applicability of AMAC to South Korean NPPs, but also for a first approximation of the activated waste volumes to be expected from Kori-1. A packaging concept based on the above activation characterization is also presented, using the AMAC algorithmic optimization software ALGOPACK leading to the minimum number of waste containers needed given the selected packaging constraints. Nagra's AMAC enables effective planning before and during NPP decommissioning, including recommendations for cutting profiles for diverse reactor components and building structures. Finally, it is expected to lead to significant cost savings by reducing the number of expensive waste containers, by optimizing a potential melting strategy for metallic waste as well as by significantly limiting the number of radiological measurements. All information about Kori-1 used for the purpose of this study was collected from publicly available sources.

• Nuclear Engineering and Technology
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• v.52 no.12
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• pp.2969-2974
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• 2020

Looking at the recent studies, nuclear energy and carbon dioxide (CO₂) emissions nexus shows inconclusive result. To further explain nuclear energy-pollution nexuses this study is an attempt to analyze the impact of nuclear energy on pollution reduction for BRICS countries covering data for the period from 1993 to 2017. This study conducts advanced panel techniques such as Continuously-Updated Fully-Modified (CUP-FM) and Continuously-Updated Bias-Corrected (CUP-BC) for long run estimation. Our results support the notion that nuclear energy reduce CO₂ emissions. Also, renewable energy corrects environmental pollution in BRICS countries. The magnitude of the coefficient of nuclear energy is less as compared to renewable energy, implying that nuclear is less effective in reducing environmental pollution. The findings offer significant policy understandings and suggestions not only for BRICS economies but for developing countries as well in designing suitable nuclear energy-growth-carbon policies.

• Advances in concrete construction
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• v.12 no.5
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• pp.419-427
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• 2021

The overuse level of cement for civil industry has several undesirable social and ecological consequences. Substitution of cement with industrial wastes, called by-products, such as fly ash, ground granulated blast furnace slag, silica fume, metakaoline, rice husk ash, etc. as the mineral admixtures offers various advantages such as technical, economical and environmental which are very important in the era of sustainability in construction industry. The paper presents the experimental investigations for assessing the mechanical properties of the concrete made using the Pozzolanic waste materials (supplementary cementitious materials) such as fly ash and silica fume as the cement replacing materials. These materials were used in eight trial mixes with varying amount of ordinary Portland cement. These SCMs were kept in equal proportions in all the eight trial mixes. The chemical admixture (High Range Water Reducing Admixture) was also added to improve the workability of concrete. The compressive strengths for 7, 28, 40 and 90 days curing were evaluated whereas the flexural and tensile strengths corresponding to 7, 28 and 40 days curing were evaluated. The study corroborates that the Pozzolanic materials used in the present investigation as partial replacement for cement can render the sustainable concrete which can be used in the rigid pavement construction.

• Advances in Energy Research
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• v.8 no.4
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• pp.203-211
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• 2022

The aim of this paper is to analyze the performance of commercial fuel cell (rated capacity 1000W) with the help of resistive load and output power variation with change in H₂ flow rate and calculate the maximum power point (MPP) of the proton exchange membrane (PEM) while changing AC and DC load respectively. The factors influencing the output power of a fuel cell are hydrogen flow rate, cell temperature, and membrane water content. The results show that when the H₂ flow rate is changed from 11, 13, and 15 Lpm, MPP is increased from lower to higher flow rate. The power of the fuel cell is increased at the rate of 29% by increasing the flow rate from 11 to 15 lpm. This study will allow small-scale industries and residential buildings (in remote or inaccessible areas) to characterize the performance of PEMFC. Furthermore, fuel cell helps in reducing emission in the environment compared to fossil fuels. Also, fuel cells are ecofriendly as well as cost effective and can be the best alternative way to convert energy.