• Journal of the Korean Applied Science and Technology
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• v.34 no.4
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• pp.892-898
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• 2017

In this study, the basic properties of recoverable gaseous and solid materials were investigated from heavy oil contained in the resources. The basic characteristics of pyrolysis reaction for the conversion of bituminous oil to pyrolysis various temperature were investigated. The characteristics of gas and solid phase byproducts were also investigated with a laboratory scale fixed bed reactor according to various reaction temperature. As a result, it was confirmed that the oil yield was about 17% at $550^{\circ}C$ and $CH_4$, $CaCO_3$ and CaO could be recovered as by-products.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.11
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• pp.127-134
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• 2015

Tissue stimulation technique using ultrasound has been continuously studied and developed. Recently, as a increment of interests for obesity treatment and cosmetic care, a various studies on ultrasonic fat emulsification has been conducted. In this study, the fat emulsification adapted ultrasonic transducer was designed. And using designed transducer, the simulation for the shape of focal area and thermal degradation region was conducted. The dimensions were verified by the simulation results. And the effectiveness was confirmed by evaluating measured radiation characteristic and heating characteristic. In addition, we estimated the ultrasonic heating characteristics in composite structure medium. The shape of focal point and heating characteristic of the proposed transducer were determined to be sufficient to emulsify the fat. The results of this study are considered to be used as basic research in more efficient and safe ultrasonic fat removal.

• International Journal of High-Rise Buildings
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• v.10 no.4
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• pp.323-334
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• 2021

Concrete structures may rarely collapse in fire incidents but fire induced damage to structural members is inevitable as a result of material degradation and thermal expansion. This requires certain repairing measures to be applied to restore the performance of post-fire members. A brief review on investigation of post-fire damage of concrete material and concrete structural members is presented in this paper, followed by a review of post-fire repair research regarding various types of repairing techniques (FRP, steel plate, and concrete section enlargement) and different type of structural members including columns, beams, and slabs. Particularly, the fire scenarios adopted in these studies leading to damage are categorized as three levels according to the duration of gas-phase temperature above 600℃ (t₆₀₀). The repair effectiveness in terms of recovered performance of concrete structural members compared to the initial undamaged performance has been summarized and compared regarding the repairing techniques and fire intensity levels. The complied results have shown that recovering the ultimate strength is achievable but the stiffness recovery is difficult. Moreover, the current fire loading scenarios adopted in the post-fire repair research are mostly idealized as constant heating rates or standard fire curves, which may have produced unrealistic fire damage patterns and the associated repairing techniques may be not practical. For future studies, the realistic fire impact and the system-level structural damage investigation are necessary.

• Korean Journal of Materials Research
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• v.28 no.11
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• pp.633-639
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• 2018

In anion exchange membrane fuel cells, Pd nanoparticles are extensively studied as promising non-Pt catalysts due to their electronic structure similar to Pt. In this study, to fabricate Pd nanoparticles well dispersed on carbon support materials, we propose a synthetic strategy using mixed organic ligands with different chemical structures and functions. Simultaneously to control the Pd particle size and dispersion, a ligand mixture composed of oleylamine(OA) and trioctylphosphine(TOP) is utilized during thermal decomposition of Pd precursors. In the ligand mixture, OA serves mainly as a reducing agent rather than a stabilizer since TOP, which has a bulky structure, more strongly interacts with the Pd metal surface as a stabilizer compared to OA. The specific roles of OA and TOP in the Pd nanoparticle synthesis are studied according to the mixture composition, and the oxygen reduction reaction(ORR) activity and durability of highly-dispersed Pd nanocatalysts with different particles sizes are investigated. The results of this study confirm that the Pd nanocatalyst with large particles has high durability compared to the nanocatalyst with small Pd nanoparticles during the accelerated degradation tests although they initially indicated similar ORR performance.

• Korean Journal of Materials Research
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• v.31 no.1
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• pp.8-15
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• 2021

Transparent, photocatalytic, and self-cleaning TiO2 thin film is developed by TiO2 sol-gel coating on glass and polycarbonate (PC) substrates. Acetyl acetone (AcAc) suppresses the precipitation of TiO2 by forming a yellowish (complex) transparent sol-gel. XPS analysis confirms the presence of Ti2p and O1s in the thin films on glass and PC substrates. The TiO2-sol is prepared by stabilizing titanium (IV) isopropoxide (TTIP) with diethylamine and methyl alcohol. The addition of AcAcsilane coupling solution to the TiO2-sol instantaneously turns to yellowish color owing to the complexing of titanium with AcAc. The AcAc solution substantially improves the photocatalytic property of the TiO2 coating layer in MB solutions. The coated TiO2 film exhibits super hydrophilicity without and with light irradiation. The TiO2 thin film stabilized by adding 8.7 wt% AcAc shows the highest photo-degradation for methylene blue (MB) solution under UV light irradiation. Also, the optimum photocatalytic activity is obtained for the 8.7 wt% AcAc-stabilized TiO2 coating layer calcined at 450 ℃. The thin-films on glass exhibit fast self-cleaning from oleic acid contamination within 45 min of UV-light irradiation. The appropriate curing time at 140 ℃ improves the anti-fogging and thermal stability of the TiO2 film coated on PC substrate. The watermark-free PC substrate is particularly beneficial to combat fogging problems of transparent substrates.

• Journal of Advanced Navigation Technology
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• v.24 no.6
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• pp.557-565
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• 2020

In order for thermal degradationIn, excore nuclear flux monitoring system, as a monitoring and signal processing methodology of reactor power, monitors neutron pulses generated during nuclear fission as frequency status, and converts them into DC voltage, and then log values resultantly. The methods realy applied in the nuclear power plant are to construct combination of counters and flip-flops, or diodes and capacitors up to now. These methodes are reliable for relative high frequencies, while not credible for reasonable low frequencies or extreme low values. Therefore, we developed the circuit that converts frequencies into DC voltages, into and into log DC values in the wide range from low Hz to several hundred high kHz. We proved their validities through testing them using real data used in nuclear power plant and analyzed their results. And, these methods will be used to measure the neutron level of excore nuclear flux monitoring system in nuclear power plant.

• Conservation Science in Museum
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• v.27
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• pp.91-102
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• 2022

Silica-based inorganic fillers for restoration of iron objects have been used for the reduction of thermal expansivity and the improvement of melt flow index. However, the higher the amount of filler is applied, the more degradation of mechanical properties and the yellowing occur, which could cause retreatment of the objects with adding stress to them. Thus, research on not only the quantification of a mixture of resin and filler but also the yellowing should be emphasized. Experiments on mechanical properties were carried out with a silica-based light filler, Micro Shell as a comparison group. The results of the experiment showed Micro Shell reduced the number of occurrences of the yellowing by 34% compared to existing fillers. The value of adhesion and specific gravity was also improved depending on the filler amount. The results of this research indicate the possibility of using Micro Shell as a new filler.

• International Journal of Industrial Entomology and Biomaterials
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• v.45 no.2
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• pp.56-69
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• 2022

Silk is a unique natural biopolymer with outstanding biocompatibility, high mechanical strength, and superior optical transparency. Due to its excellent properties, silk has been widely reported as an ideal biomaterial for several biomedical applications. Recently, fluorescent silk protein, a variant of native silk, has been reported as a biophotonic material with the potential for bioimaging and biosensing. Despite the realization of fluorescent silk, the traditional degumming process of fluorescence silk is crude and often results in fluorescence loss. The loss of fluorescent properties is attributed to the sensitivity of silk fibroin to temperature and solvent concentration during degumming. However, there is no comprehensive information on the influence of these processing parameters on fluorescence evolution and decay during fluorescent silk processing. Therefore, we conducted a spectroscopic study on fluorescence decay as a function of temperature, concentration, and duration for fluorescent silk cocoon degumming. Sodium carbonate solution was tested for degumming the fluorescent silk cocoons with different concentrations and temperatures; also, sodium carbonate solution is combined with Alcalase enzyme and triton x-100 to find optimal degumming conditions. Additionally, we conducted a molecular dynamics study to investigate the fundamental effect of temperature on the stability of the fluorescent protein. We observed degumming temperature as the prime source of fluorescent intensity reduction. From the MD study, fluorescence degradation originated from the thermal agitation of fluorescent protein Cα atoms and fluctuations of amino acid residues located in the chromophore region. Overall, degumming fluorescent silk with sodium carbonate and Alcalase enzyme solution at 25 ℃ preserved fluorescence.

• International Journal of Computer Science & Network Security
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• v.22 no.9
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• pp.109-116
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• 2022

The energy corporation of Kosovo continuously monitors and analyzes the impact of its own activities on the environment. Regarding the environmental situation, energy corporation of Kosovo- ECK regularly informs and reports objectively to the competent state institutions, local municipal institutions and interested parties. ECK, through numerous contacts with the competent authorities, firstly with different ministers, harmonizes the positions regarding environmental issues in the direction of achieving certain environmental standards or legal requirements in order to gradually be in accordance with them, based on the real possibilities, especially the financial ones. From this point of view, the environmental issue is very sensitive, quite complex and represents one of the biggest challenges of society currently and in the future. The researched variables show a continuous increase in the need for electricity production in Kosovo and this increase in production conditions a wide range of environmental impacts both at the local, regional and global levels. The aim of the work is to reduce the emission of pollutants through the main variables without inhibiting the economic development of the country, i.e. to bring the pollution as a result of the activities of the ECK operation into compliance with the permitted environmental norms. As a result of ECK's operational activities, the following follows: Air pollution mainly as a result of emissions from TCs in the air, transport, etc. Water pollution - as a result of technological water discharges, Land degradation - as a result of surface mining activities of the entire mining area. The purpose of the paper is to research and analyze the main water variables in the area of the Kosova B power plant, which is to determine the degree of their pollution from the activities of the power plants, as well as to assess the real state of surface water quality and control the degree of pollution of these waters. Methodology of the work: The analyzes of the water samples were done in the company Institute "INKOS" JSC by simultaneous methods using different reagents.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.17 no.1
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• pp.18-27
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• 2021

This study aims to develop an improved evaluation technology for assessing CANDU-6 safety. For this purpose, the multiple steam generator tube rupture (mSGTR) followed by an unmitigated station blackout (SBO) in a CANDU-6 plant was selected as a hypothetical event scenario and the analysis model to evaluate the plant responses was envisioned into the MARS-KS input model. The model includes logic models for controlling the pressure and inventory of the primary heat transport system (PHTS) decreasing due to the u-tubes' rupture, as well as the main features of PHTS with a simplified model for the horizontal fuel channels, the secondary heat transport system including the shell side of steam generators, feedwater and main steam line, and moderator system. A steady state condition was successfully achieved to confirm the stable convergence of the key parameters. Until the turbine trip, the fuel channels were adequately cooled by forced circulation of coolant and supply of main feedwater. However, due to the continuous reduction of PHTS pressure and inventory, the reactor and turbine were shut down and the thermal-hydraulic behaviors between intact and broken loops got asymmetric. Furthermore, as the conditions of low-flow coolant and high void fraction in the broken loop persisted, leading to degradation of decay heat removal, it was evaluated that the peak cladding temperature (PCT) exceeded the limit criteria for ensuring nuclear fuel integrity. This study is expected to provide the technical bases to the accident management strategy for transient conditions with multiple events.