• Korean Journal of Environmental Agriculture
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• v.40 no.1
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• pp.13-19
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• 2021

BACKGROUND: Chemicals such as antibiotics and surfactants can enter agricultural environment and they can be degraded by natural processes such as photolysis. These chemicals exist in mixtures in the environment, but studies on degradation of the mixtures are limited. This study compares the photodegradation of Triton X-100 (TX) and antibiotics [tetracycline (TC) and sulfathiazole (STH)] when they are in a single solution or in mixtures. METHODS AND RESULTS: TC, STH, and TX solutions were exposed to UV-A for the photodegradation tests for 14 days. The residual TC, STH, and TX concentrations were analyzed by using HPLC. The TC degradation was similar regardless of the presence of TX, while the TX degradation was lower in the presence of TC. The STH degradation was similar regardless of the presence of TX, while the TX degradation was greater in the presence of STH. However, the STH degradation was slower in the TC-STH-TX mixture than in the STH-TX mixture. Also, the TX degradation was negligible in the TC-STH-TX mixture. The results show that the photodegradation of TC, STH, and TX can be different in mixtures. This can be attributed to the different emission and absorption wavelengths of each compound and interaction between these compounds and photoproducts. CONCLUSION: Overall, this study emphasizes that photodegradation of single chemicals and chemical mixtures can be different, and more studies on single compounds as well as mixtures are required to understand the fate of chemicals in the environment in order to manage them properly.

• The Journal of the Convergence on Culture Technology
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• v.7 no.3
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• pp.285-292
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• 2021

In Sapiens it shows the reason that sapiens has conquered the earth for the invention of intersubjective reality. In Homodeus sapiens made the science revolution through the religion of humanism. The development of science showed that human free will and emotion is just made through the chemical interaction of neuron which can be manipulated and developed. Algorithm and data wlll be the sovereign which make decision in everything. Yuval Harari tells us the Homodeus appear and break down the order of equality. His anticipation proves right in competition law issues. The collusion through the algorithm makes it difficult to apply existing cartel logic. Agreement is the ground of responsibility but undertaking is not responsible in the market where sovereign algorithm decides eveything. Extreme price differentiation can appear and break down the existing market logic and competition dogma. Everything changes and it is necessary to have the flexible attitude and develop new logic.

• CELLMED
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• v.11 no.3
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• pp.15.1-15.9
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• 2021

The chemical constitution of a drug has been accepted as an important basis for pharmacological action in Unani medicine. Various dosage forms have been developed on this concept, such as decoctions (Joshanda), infusions (Khesanda), extract (Rub / Usara), and syrup. Zarawand Mudaharaj (ZM.) / Aristolochia rotunda L. root was subjected to extraction process using Soxhlet's apparatus by using Response Surface Methodology (RSM) to design the number of random runs of the extracts with variation in the factors of temperature, the concentration of ethanol in water, time for extraction, for optimizing and maximizing the yield concentration. The data obtained, was analyzed with regression equation and ANOVA two-way summary to interpret the interaction of the factors for yield maximization. Minitab version 18 was used to design and analyze data. Validation of the optimum conditions for maximum yield of the whole extract of ZM. Root was carried out by re-run of the extract using the optimized conditions. The maximum yield percentage thus obtained using RSM was 20.87% whereas using these optimum conditions 21.35 % yield was obtained thereby validating the method. The association between the response functions and the process variables was identified by a three-factor recorded Box-Behnken design. In the present study RSM is used because itis a cheap and affordable method to optimize maximum yield percentage which may be reliably used by researchers. The study set in the surface conditions for ZM. root extraction by the Soxhlet apparatus for maximizing the yield percentage.

• Journal of Convergence for Information Technology
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• v.12 no.4
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• pp.119-125
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• 2022

In the study, we endeavored to investigate the effect of phenylephrine, isoprenaline and prazosin on the tissue-specific vascular contractility and to determine the mechanism involved. There were few reports addressing the question whether thin or thick filament modulation is included in phenylephrine, isoprenaline and prazosin-induced regulation. We hypothesized that isoprenaline and prazosin play a role in tissue-dependent regulation of vascular contractility. Denuded arterial muscles of Sprague-Dawley male rats were suspended in organ baths and isometric tensions were transduced and recorded using isometric transducers and an automatic data acquisition system. Interestingly, sustained continuous contraction of thoracic and abdominal aorta. Furthermore, isoprenaline and prazosin together with phenylephrine inhibited transiently and persistently vasoconstriction of thoracic and abdominal aorta suggesting that additional mechanisms (e.g. decreased receptor density, chemical interaction, postreceptor signaling or distribution of agonists) might be included in the modulation of vascular contractility.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.35 no.5
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• pp.439-444
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• 2022

Laser-induced plasmonic sintering of metal nanoparticles (NPs) is a promising technology to fabricate flexible conducting electrodes, since it provides instantaneous, simple, and scalable manufacturing strategies without requiring costly facilities and complex processes. However, the metal NPs are quite expensive because complicated synthesis procedures are needed to achieve long-term reliability with regard to chemical deterioration and NP aggregation. Herein, we report laser-induced Ag NP self-generation and sequential sintering process based on low-cost Ag organometallic material for demonstrating high-quality microelectrodes. Upon the irradiation of laser with 532 nm wavelength, pre-baked Ag organometallic film coated on a transparent polyimide substrate was transformed into a high-performance Ag conductor (resistivity of 2.2 × 10^-4 Ω·cm). To verify the practical usefulness of the technology, we successfully demonstrated a wearable transparent heater by using Ag-mesh transparent electrodes, which exhibited a high transmittance of 80% and low sheet resistance of 7 Ω/square.

• Journal of Powder Materials
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• v.29 no.2
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• pp.99-109
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• 2022

Powder flowability is critical in additive manufacturing processes, especially for laser powder bed fusion. Many powder features, such as powder size distribution, particle shape, surface roughness, and chemical composition, simultaneously affect the flow properties of a powder; however, the individual effect of each factor on powder flowability has not been comprehensively evaluated. In this study, the impact of particle shape (sphericity) on the rheological properties of Ti-6Al-4V powder is quantified using an FT4 powder rheometer. Dynamic image analysis is conducted on plasma-atomized (PA) and gas-atomized (GA) powders to evaluate their particle sphericity. PA and GA powders exhibit negligible differences in compressibility and permeability tests, but GA powder shows more cohesive behavior, especially in a dynamic state, because lower particle sphericity facilitates interaction between particles during the powder flow. These results provide guidelines for the manufacturing of advanced metal powders with excellent powder flowability for laser powder bed fusion.

• Advances in aircraft and spacecraft science
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• v.9 no.3
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• pp.195-215
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• 2022

The increasing interest in CubeSat platforms ant their capability of enlarging the frontier of possible missions impose technology improvements. Miniaturized electrical propulsion (EP) systems enable new mission for multi-unit CubeSats (6U+). While electric propulsion systems have achieved important level of knowledge at equipment level, the investigation of the mutual impact between EP system and CubeSat technology at system level can provide a decisive improvement for both the technologies. The interaction between CubeSat and EP system should be assessed in terms of electromagnetic emissions (both radiated and conducted), thermal gradients, high electrical power management, surface chemical deposition, and quick and reliable data exchanges. This paper shows how a versatile CubeSat Test Platform (CTP), together with standardized procedures and specialized facilities enable the acquisition fundamental and unprecedented information. Measurements can be taken both by specific ground support equipment placed inside the vacuum facility and by dedicated sensors and subsystems installed on the CTP, providing a completely new set of data never obtained before. CTP is constituted of a 6U primary structure hosting the EP system, representative CubeSat avionics and batteries. For the first test campaign, CTP hosts the ambipolar plasma propulsion system, called Regulus and developed by T4I. After the integration and the functional test in laboratory environment, CTP + Regulus performed a Test campaign in relevant environment in the vacuum chamber at CISAS, University of Padua. This paper is focused on the test campaign description and the main results achieved at different power levels for different duration of the firings.

• Journal of Environmental Science International
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• v.31 no.8
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• pp.691-706
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• 2022

Magnetic activated carbon was prepared by adding a magnetic material to activated carbon that had been prepared from waste citrus peel in Jeju. The adsorption characteristics of an aqueous solution of the antibiotic trimethoprim (TMP) were investigated using the magnetic activated carbon, as an adsorbent, and response surface methodology (RSM). Batch experiments were carried out according to a four-factor Box-Behnken experimental design affecting TMP adsorption with their input parameters (TMP concentration: 50~150 mg/L; pH: 4~10; temperature: 293~323 K; adsorbent dose: 0.05~0.15 g). The significance of the independent variables and their interaction was assessed by ANOVA and t-test statistical techniques. Statistical results showed that TMP concentration was the most effective parameter, compared with others. The adsorption process can be well described by the pseudo-second-order kinetic model. The experimental isotherm data followed the Langmuir isotherm model. The maximum adsorption capacities of TMP, estimated with the Langmuir isotherm model were 115.9-130.5 mg/g at 293-323 K. Also, both the thermodynamic parameters, ΔH and ΔG, have both positive values, indicating that the adsorption of TMP by the magnetic activated carbon is an endothermic reaction and proceeds via an involuntary process.

• Korean Journal of Materials Research
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• v.33 no.8
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• pp.337-343
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• 2023

3Y-TZP (3 mol% yttria-stabilized tetragonal zirconia polycrystals) ceramics have excellent mechanical properties including high fracture toughness, good abrasion resistance as well as chemical and biological stability. As a result, they are widely used in mechanical and medical components such as bearings, grinding balls, and hip implants. In addition, they provide excellent light transmittance, biocompatibility, and can match tooth color when used as a dental implant. Recently, given the materials' resemblance to human teeth, these ceramics have emerged as an alternative to titanium implants. Since the introduction of CAD/CAM in the manufacture of ceramic implants, they've been increasingly used for prosthetic restoration where aesthetics and strength are required. In this study, to improve the surface roughness of zirconia implants, we modified the 3Y-TZP surface with a biocomposite of hydroxyapatite and forsterite using room temperature spray coating methods, and investigated the mixed effect of the two powders on the evolution of surface microstructure, i.e., coating thickness and roughness, and biological interaction during the in vitro test in SBF solution. We compared improvement in bioactivity by observing dissolution and re-precipitation on the specimen surface. From the results of in vitro testing in SBF solution, we confirmed improvement in the bioactivity of the 3Y-TZP substrate after surface modification with a biocomposite of hydroxyapatite and forsterite. Surface dissolution of the coating layer and the precipitation of new hydroxyapatite particles was observed on the modified surface, indicating the improvement in bioactivity of the zirconia substrate.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.374-374
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• 2023

Groundwater is the main source of water on which relies many countries in case of emergency, this is the case of Japan in 2011 after the great Sendai Earthquake. This important resource is found to be heavily influenced by human induced factors such as wetland area reduction. For groundwater sustainable management in perfect cohesion with wetland it is important to understand the relationship between both resources. Wetlands have a strong interaction with both groundwater and surface water, influencing catchment hydrology and water quality. Quantifying groundwater-wetland interactions can help better identify locations for wetlands restoration and/or protection. This study uses observation data from piezometers and wetland to study the qualitative and quantitative aspects of the correlation. Groundwater level, wetland area, chemical, organic and inorganic contaminants are the important parameters used. the results proved that few contaminants in the wetland are found in groundwater and in general the wetland quality does not affect that much groundwater quality. The strong linear relationship found between wetland water level and nearest groundwater level proved that, in term of quantity, groundwater and wetland are strongly correlated. While wetland becoming dry, groundwater level has dropped in the region about 0.52m. The area of wetland was found to be lightly correlated with groundwater level, proving that wetlands dry has contributed to groundwater level declining. This study has showed that whilst rainfall variability contributed to the decline and loss of wetlands, the impacts from landuse changes and groundwater extraction were likely to be significant contributors to the observed losses.