• Clean Technology
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• v.13 no.3
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• pp.228-234
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• 2007

In this study, the productivity and environmental effects of laser aided direct metal deposition (LADMD) process which is one of promising rapid manufacturing technology is evaluated. The production time predicted using PowerMill shows that the productivity of LADMD is superior to that of conventional milling process. Though LADMD is known as an environment-friendly technology, it has a disadvantage to utilize much energy to generate laser beam. Considering both productivity and environmental effects, LADMD is expected to be widely used in remanufacturing industry.

• Clean Technology
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• v.20 no.2
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• pp.160-165
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• 2014

Over the past decade, an increasing number of manufactured nanoparticles (NPs) have been incorporated into products and manufacturing processes due to the rapid innovation and commercialization in the field of nanotechnology. In addition, these nanomaterials and nano-consumer products have increased in quantity per year, and thus their uncontrolled release into the environment is anticipated to grow dramatically in future. However, A current sewage/wastewater treatment plant (SWTP) is being applied to removal of nanoparticles in wastewater. In Korea, the study on the removal of nanoparticles in SWTP was not reported yet. Therefore, in this work, to design pilot STP before field test, two model equations and commercial process simulation were used to derive the desing parameters.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.05b
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• pp.82-86
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• 2004

This research is about the result of leakage current waveform about the situation of surface leakage current and environmental changes(Salt fog, clean fog and rain) by EPDM polymer insulators' amount of salt. The researcher presents the result of changing about fundamental harmonic, 3rd harmonic and 5th harmonic from starting point of supplying power to flashover. In this study, researched environmental affects (clean fog, salt fog and rain) about surface aging of polymer insulators and used frequency spectrum of leakage current waveform to develop the diagnostic technique of surface aging. When amount of salt contents changed, surface aging stage and the degree of aging (distortion factor) about 3rd and 5th harmonic waveform on low frequency harmonic wave. The distortion factor which is harmonic percentage about basic harmonic is important pointer to evaluate the surface condition of polymer insulators.

• Journal of Information Technology Services
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• v.14 no.4
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• pp.45-60
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• 2015

Governments around the world invest in research and development (R&D) for different purposes : national economy, defence, environment, health, etc. as a means of national survival beyond the means of national competitiveness. These are usually programs with high social impact but low short-term economic impact or large scientific programs that are too expensive and risky for private sector investment alone. The Republic of Korea has also shown a very successful model of economic progress and social development through government R&D programs. However, there have been many corruption scandals behind it while selecting awardees for government R&D programs in Korea. So, the Republic of Korea focused on reforming appraisal system for government R&D and began preparation for "Clean Appraisal System" last year. In this study, first we analyzed the related appraisal tasks through the review of laws and administrative rules and typed appraisal tasks according to the flow of the actors and time. Thus securing the information infrastructure and finally we drew the conceptual model of the system according to an open appraisal tasks by introducing an element of the OECD on open government typed appraisal tasks.

• Nuclear Engineering and Technology
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• v.53 no.6
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• pp.2056-2065
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• 2021

The transition toward clean energy is an issue of great importance with growing debate in climate change mitigation. The complex nature of nuclear energy-CO₂ emissions nexus makes it difficult to predict whether or not nuclear acts as a clean energy source. Hence, we examined the relationship between nuclear energy consumption and CO₂ emissions in the context of the IPAT and Environmental Kuznets Curve (EKC) framework. Dynamic Auto-regressive Distributive Lag (DARDL), a newly modified econometric tool, is employed for estimation of long- and short-run dynamics by using yearly data spanning from 1971 to 2018. The empirical findings of the study revealed an instantaneous increase in nuclear energy reduces environmental pollution, which highlights that more nuclear energy power in the Indian energy system would be beneficial for climate change mitigation. The results further demonstrate that the overarching effect of population density in the IPAT equation stimulates carbon emissions. Finally, nuclear energy and population density contribute to form the EKC curve. To achieving a cleaner environment, results point out governmental policies toward the transition of nuclear energy that favours environmental sustainability.

• Corrosion Science and Technology
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• v.17 no.6
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• pp.301-309
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• 2018

If galvanized steel is exposed to an outdoor environment, atmospheric corrosion will occur with time and red rust will form when the sacrificial protection capacity of zinc reaches its limit. With corrosion, the surface appearance of steel changes, and the properties of the exterior materials degrade. In this study, two kinds of galvanized steel, (GA and GI specimens) were subjected to an outdoor exposure test for 36 months in six regions of Korea. Chrominance (color, chroma, and brightness) and glossiness surface analyses were performed. The color change was not significant, regardless of the exposed area or the specimens tested. With increasing exposure times, the GA specimen became blackened by the formation of zinc oxide, and red coloration was increased by the formation of red rust. As the exposure time of GI specimen increased, the surface proceeded to blacken, but no red rust was formed and the color did not change significantly. Regardless of the outdoor exposure area or the specimen, longer exposure times led to lower glossiness, and this behavior appears to be influenced by the formation of zinc oxide.

• Clean Technology
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• v.28 no.1
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• pp.32-37
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• 2022

Food waste is produced from food factories, food services, and home kitchens. The generated mass reached 5.4 million tons/year in 2020. The basic management technology for such waste has been biological degradation under an anaerobic environment. However, the whole process is intrinsically slow and considerably affected by the inner physicochemical properties of the waste and other surrounding conditions, which makes optimization of the process difficult. The most promising options to counter this massive generation of waste are eco-friendly treatments or recycling. As a preliminary step for these options, attempts were made to evaluate the feasibility and usability of three simulative models based on reaction kinetics. Model (A) predicted relative changes over reaction time for reactant, intermediate, and product. Overall, an increased reaction rate produced less intermediate and more product, thereby leading to a shorter total reaction time. Particle diminishing model (B) predicted reduction of the total waste mass. The smaller particles diminished faster along with the dominant effect of microbial reaction. In Model (C), long-chain cellulose was predicted to transform into reducing sugar. At a standard condition, 48% of cellulose molecules having 10⁵ repeating units turned into reducing sugar after 100 h. Also it was found that the optimal enzyme concentration where the highest amount of remnant sugar was harvested was 1 mg L^-1.

• Clean Technology
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• v.29 no.3
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• pp.172-177
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• 2023

Many studies have been conducted on the indiscriminate use of plastic due to the environment problems it has caused all over the world. This problem can be mitigated by using eco-friendly/biodegradable plastics that can be decomposed by microorganisms or enzymes. This study focused on addressing the plastic golf tees that are thrown away at golf courses. In order to replace conventional golf tees (ABS) with a more eco-friendly alternative, this study explored a biodegradable plastic and 3D printing method for producing golf tees. Among the biodegradable plastics, PLA (polylactic acid) was found to be a good candidate as an eco-friendly material because it is biodegradable by microorganisms. Thus, golf tees were prepared by using PLA via 3D printing, and the physical and chemical properties of the tees were evaluated. The amorphous region of PLA was confirmed through XRD. Also, FT-IR showed the unique peak of PLA without impurities. It was confirmed through an optical microscope that the specific surface area and roughness had increased. This structure plays a role in firmly fixing the golf tee when it is inserted into the ground. In addition, it was possible to improve the compressive load compared to ABS golf tees while also decreasing the compressive stretching.

• Clean Technology
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• v.15 no.2
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• pp.75-80
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• 2009

In order to separate oxygen from air, the effects of feed gas flow rate and rinse gas flow rate on the product purity and flow were examined using 2 bed PSA with 4 step cycle. The addition of product pressurization step increased the product purity and flow rate. The addition of pressure equalization increased the product flow rate. The test product was manufactured and the purity and flow rate of product oxygen was examined. The results were compared with the commercial medical oxygen generator of 5 ${\ell}/min$ and 90% oxygen purity.

• International Journal of Computer Science & Network Security
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• v.24 no.1
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• pp.31-44
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• 2024

People have been using more energy in the last years. Several research studies were conducted to develop sustainable energy sources that can produce clean energy to fulfill our energy requirements. Using renewable energy sources helps to decrease the harm to the environment caused by conventional power plants. Choosing the right location and capacity for DG-RESs can greatly impact the performance of Radial Distribution Systems. It is beneficial to have a good and stable electrical power supply with low energy waste and high effectiveness because it improves the performance and reliability of the system. This research investigates the ideal location and size for solar and wind power systems, which are popular methods for producing clean electricity. A new artificial intelligent algorithm called Nutcracker Optimization Algorithm (NOA) is used to find the best solution in two common electrical systems named IEEE 33 and 69 bus systems to examine the improvement in the efficiency & reliability of power system network by reducing power losses, making voltage deviation smaller, and improving voltage stability. Finally, the NOA method is compared with another method called PSO and developed Hybrid Algorithm (NOA+PSO) to validate the proposed algorithm effectiveness and enhancement of both efficiency and reliability aspects.