• 산업경영시스템학회지
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• 제46권spc호
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• pp.31-38
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• 2023

In this study, in order to develop a method to efficiently inject essential nutrients necessary for plant growth into wood chips, which are simply used as soil covering materials in the agriculture, landscaping and horticultural industries, the atmospheric pressure dipping method and the vacuum pressure impregnating method are used to improve the plant nutrients injectability and impregnation amount were comparatively analyzed. Nutrient ingredients and 8 major heavy metal contents of wood chips injected with nutrients were analyzed, and soil covering effects were examined by covering wood chips injected with nutrients on soil. Comparing the dipping method and the vacuum pressure impregnation method, it took about 48 hours or more to inject 1,500 g or more of the nutrient aqueous solution into 1 kg of wood chips in the dipping method, but the vacuum pressure impregnation method could be impregnated in about 5 minutes. Components of the impregnated nutrients were detected in proportion to the diluted concentration. As a result of covering the wood chips developed in this study on soil, they showed weakly acidic pH, and the heat insulation and moisturizing effects during the winter season were evaluated to be superior to those of uncovered soil. In the future, wood chips impregnated with nutrients are expected to contribute to the more efficient use of waste wood resources and the long-term supply of nutrients essential for plant growth, reducing excessive use of chemical fertilizers and reducing costs.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제18권1호
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• pp.46-63
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• 2024

One of the biggest dangers in the globe is water contamination. Water is a necessity for human survival. In most cities, the digging of borewells is restricted. In some cities, the borewell is allowed for only drinking water. Hence, the scarcity of drinking water is a vital issue for industries and villas. Most of the water sources in and around the cities are also polluted, and it will cause significant health issues. Real-time quality observation is necessary to guarantee a secure supply of drinking water. We offer a model of a low-cost system of monitoring real-time water quality using IoT to address this issue. The potential for supporting the real world has expanded with the introduction of IoT and other sensors. Multiple sensors make up the suggested system, which is utilized to identify the physical and chemical features of the water. Various sensors can measure the parameters such as temperature, pH, and turbidity. The core controller can process the values measured by sensors. An Arduino model is implemented in the core controller. The sensor data is forwarded to the cloud database using a WI-FI setup. The observed data will be transferred and stored in a cloud-based database for further processing. It wasn't easy to analyze the water quality every time. Hence, an Optimized Neural Network-based automation system identifies water quality from remote locations. The performance of the feed-forward neural network classifier is further enhanced with a hybrid GA- PSO algorithm. The optimized neural network outperforms water quality prediction applications and yields 91% accuracy. The accuracy of the developed model is increased by 20% because of optimizing network parameters compared to the traditional feed-forward neural network. Significant improvement in precision and recall is also evidenced in the proposed work.

• Tribology and Lubricants
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• 제40권3호
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• pp.91-96
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• 2024

Recently, extensive studies have been carried out to enhance various performance aspects such as the durability, lifespan, and hardness by combining diverse materials or developing novel materials. The utilization of superhydrophobic surfaces, particularly in the automotive, textile, and medical device industries, has gained momentum to achieve improved performance and efficiency. Superhydrophobicity refers to a surface state where the contact angle when water droplets fall is above 150°, while the contact angle during sliding motion is smaller than 10°. Superhydrophobic surfaces offer the advantage of water droplets not easily sliding off, maintaining a cleaner state as the droplets leave the surface. Surface modification involves two fundamental steps to achieve superhydrophobicity: surface roughness increase and surface energy reduction. However, existing methods, such as time-consuming processes and toxic organic precursors, still face challenges. In this study, we propose a method for superhydrophobic surface modification using lasers, aiming to create roughness in micro/nanostructures, ensuring durability while improving the production time and ease of fabrication. The mechanical durability of superhydrophobic samples treated with lasers is comparatively evaluated against chemical etching samples. The experimental results demonstrate superior mechanical durability through the laser treatment. Therefore, this research provides an effective and practical approach to superhydrophobic surface modification, highlighting the utility of laser treatment.

• 한국건축시공학회지
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• 제24권3호
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• pp.285-295
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• 2024

본 연구에서는 500℃·hr의 증기양생을 실시한 OPC 페이스트에 대하여 1atm 20% 농도의 CO₂와 5atm 99% 농도의 고농도 CO₂ 조건 하의 촉진 탄산화의 영향평가를 수행하였다. 이를 위하여 XRD, FT-IR을 통한 화학적 분석과 SEM, 압축강도 측정을 통한 물리적 특성 분석을 실시하였다. 그 결과 CO₂ 20% 농도의 상압 탄산화를 수행하는 경우 뚜렷한 내부 조직구조 치밀화 및 압축강도 증진 효과를 관찰할 수 있었고, CO₂ 99% 농도의 5atm 가압 탄산화를 실시할 경우 표면조직구조가 빠르게 치밀해지며 CO₂ 확산침투율이 크게 떨어지게 되어 압축강도 등 유의미한 수준의 물리적 특성 개선이 일어날 정도의 탄산화를 진행할 수 없었다.

• 농업과학연구
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• 제49권4호
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• pp.749-760
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• 2022

Omics-driven synthetic biology is a multidisciplinary research field that creates new artificial life by employing genetic components, biological devices, and engineering technique based on genetic knowledge and technological expertise. It is also utilized to make valuable biomaterials with limited production via current organisms faster, more efficient, and in huge quantities. As the bioeconomic age begins, and the global synthetic biology market becomes more competitive, investment in research and development (R&D) and associated sectors has grown considerably. By overcoming the constraints of present biotechnologies through the merging of big data and artificial intelligence technologies, huge ripple effects are envisaged in the pharmaceutical, chemical, and energy industries. In agriculture, synthetic biology is being used to solve current agricultural problems and develop sustainable agricultural systems by increasing crop productivity, implementing low-carbon agriculture, and developing plant-based, high-value-added bio-materials such as vaccines for diagnosing and preventing livestock diseases. As international regulatory debates on synthetic biology are now underway, discussions should also take place in our country for the growth of bioindustries and the dissemination of research findings. Furthermore, the system must be improved to facilitate practical application and to enhance the risk evaluation technology and management system.

• 한국작물학회지
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• 제60권2호
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• pp.231-238
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• 2015

본 시험은 컬러감자의 안토시아닌 함량에 영향을 미치는 환경요인을 구명하기 위하여 수행되었다. 컬러감자 '홍영'과 '자영'을 전국 감자 주요 재배지역 14곳에 파종한 후 각 지역의 토양 화학성과 기상환경 조건을 분석하였고, 각 지역에서 생산된 감자 괴경의 안토시아닌 함량을 분석하였다. 아울러 분석된 안토시아닌 함량과 토양 및 기상환경과의 관련성을 상관분석을 통해 조사하였다. 품종 간 비교에서는 시험이 수행된 대부분의 지역에서 자주색 '자영'이 붉은색 '홍영'보다 안토시아닌 함량이 높은 것으로 나타났다. 지역을 고랭지, 준고랭지 및 평난지로 구분하였을 때, 대체적으로 고도가 높은 지역에서 생산된 컬러감자의 안토시아닌 함량이 높았다. 수확된 컬러감자 괴경의 안토시아닌 함량과 토양의 화학적 성분과의 상관분석에서는 유일하게 토양산도와 유의성 있는 부의 상관계수를 보였다. 또한 안토시아닌 함량과 기상환경 조건들과의 상관분석에서는 파종후 80~100일 사이의 평균온도 및 최저온도와 유의성 있는 부의 상관계수를 보였다. 즉, 이 시기의 평균온도와 최저온도가 낮은 지역에서 안토시아닌 함량이 높은 컬러감자 괴경이 생산되었다. 이상의 결과는 고품질의 컬러감자를 생산하기 위한 적지선정이 필요한 생산자와 산업체에 유용한 정보로 활용될 것으로 기대된다.

• 한국환경과학회지
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• 제26권11호
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• pp.1297-1306
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• 2017

This study identified physical characteristics and aerosol particle sources of $PM_{10}$ and $PM_{2.5}$ in the industrial complex of Busan Metropolitan City, Korea. Samples of $PM_{10}$, $PM_{2.5}$ and also soil, were collected in several areas during the year of 2012 to investigate elemental composition. A URG cyclone sampler was used for collection. The samples were collected according to each experimental condition, and the analysis method of SEM-EDX was used to determine the concentration of each metallic element. The comparative analysis indicated that their mass concentration ranged from 1% to 3%. The elements in the industrial region that were above 10% were Si, Al, Fe, and Ca. Those below 5% were Na, Mg, and S. The remaining elements (1% of total mass) consisted of elements such as Ni, Co, Br and Pb. Finally, a statistical tool was applied to the elemental results to identify each source for the industrial region. From a principal components analysis (SPSS, Ver 20.0) performed to analyze the possible sources of $PM_{10}$ in the industrial region, five main factors were determined. Factor 1 (Si, Al), which accounted for 15.8% of the total variance, was mostly affected by soil and dust from manufacturing facilities nearby, Factors 2 (Cu, Ni), 3 (Zn, Pb), and 4 (Mn, Fe), which also accounted for some of variance, were mainly related to iron, non-ferrous metals, and other industrial manufacturing sources. Also, five factors determined to access possible sources of $PM_{2.5}$, Factor 1 (Na, S), accounted for 13.5% of the total variance and was affected by sea-salt particles and fuel incineration sources, and Factors 2 (Ti, Mn), 3 (Pb, Cl), 4 (K, Al) also explained significant proportions of the variance. Theses factors mean that the $PM_{2.5}$ emission sources may be considered as sources of incineration, and metals, and non-ferrous manufacturing industries.

• Bulletin of the Korean Chemical Society
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• 제30권9호
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• pp.2021-2026
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• 2009

Toluene, xylene and styrene are volatile organic solvents that are commonly used in mixtures in many industries. Because these solvents are metabolized and then excreted in urine, their urinary metabolites are thought to be biomarkers of occupational exposure to these solvents. Therefore, a simple, rapid, and yet reliable analytical method for determining the metabolites is required for accurate biological monitoring. In the present study, a simple and rapid HPLC-UV method was developed for the simultaneous determination of eight major metabolites of toluene, xylene and styrene: hippuric acid (HA), mandelic acid (MA), o-, m- and p-methylhippuric acids (o-, m- and p-MHAs), and o-, m- and p-cresols. A monolithic column was employed as the stationary phase and several conditions, including flow rate, composition of mobile phase and column temperature, were variables for the optimization of the chromatographic resolution. All eight metabolites were successfully resolved within 5 minutes in 10% aqueous ethanol containing 0.3% acetic acid and 1.6% $\beta$-cyclodextrin, using a flow rate gradient of 1.0 - 5.0 mL/min at 25 ${^{\circ}C}$. The performance of this method was validated by linearity, intra- and inter-day accuracy, and precision. The linearity was observed with correlation coefficients of 0.9998 for HA, 0.9999 for MA, 0.9989 for o-MHA, 0.9998 for m-MHA, 0.9991 for p-MHA, 0.9997 for o-cresol, 0.9998 for m-cresol, and 0.9986 for p-cresol. The intra- and inter-day precision of the method were less than 5.89% (CV) and the accuracy ranged from 92.95 to 106.62%. The validity was further confirmed by analysis of reference samples that were prepared by the inter-laboratory quality assurance program of the Korea Occupational Safety and Health Agency (KOSHA, Seoul, Korea). All measured concentrations of the analytes agreed with the certified values.

• 수산해양기술연구
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• 제25권2호
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• pp.87-104
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• 1989

Recently, with the tendency of more lightening, high-strength and high-speed in the marine industries such as marine structures, ships and chemical plants, the use of the aluminium Alloy is rapidly enlarge and there occurs much interest in the study of corrosion fatigue crack characteristics. In this paper, the initiation of surface crack and the propagation characteristics on the base metal and weld zone of 5086-H116 Aluminium Alloy Plate which is one of the Al-Mg serious alloy(A5000serious) used most when building the special vessels, were investigated by the plane bending corrosion fatigue under the environments of marine, air and applying cathodic protection. The effects of various specific resistances on the initiation, propagation behavior of corrosion fatigue crack and corrosion fatigue life in the base metal and heat affected zone were examined and its corrosion sensitivity was quantitatively obtained. The effects of corrosion on the crack depth in relation to the uniform surface crack length were also investigated. Also, the structural, mechanical and electro-chemical characteristics of the metal at the weld zone were inspected to verify the reasons of crack propagation behavior in the corrosion fatigue fracture. In addition, the effect of cathodic protection in the fracture surface of weld zone was examined fractographically by Scanning Electron Microscope(S.E.M.). The main results obtained are as follows; (1) The initial corrosion fatigue crack sensitibity under specific resistance of 25Ω.cm% show 2.22 in the base metal and 19.6 in the HEZ, and the sensitivity decreases as specific resistance increases (2) By removing reinforcement of weldment, the initiation and propagation of corrosion crack in the HAZ are delayed, and corrosion fatigue life increases. (3) As specific resistance decreases, the sensitivity difference of corrosion fatigue life in the base metal and HAZ is more susceptible than that of intial corrosion fatigue crack. (4) Experimental constant, m(Paris' rule) in the marine environment is in the range of about 3.69 to 4.26, and as specific resistance increases, thje magnitude of experimental constant, also increases and the effect by corrosion decreases. (5) Comparing surface crack length with crack depth, the crack depth toward the thickness of specimen in air is more deeply propagated than that in corrosion environment. (6) The propagation particulars of corrosion fatigue crack for HAZ under initial stress intensity factor range of $\Delta$k sub(li) =27.2kgf.mm super(-3/2) and stress ratio of R=0 shows the retardative phenomenon of crack propagation by the plastic deformation at crack tip. (7) Number of stress cycles to corrosion fatigue crack initiation of the base metal and the welding heat affected zone are delayed by the cathodic protection under the natural sea water. The cathodic protection effect for corrosion fatigue crack initiation is eminent when the protection potential is -1100 mV(SCE). (8) When the protection potential E=-1100 mV(SCE), the corrosion fatigue crack propagation of welding heat affected zone is more rapid than that of the case without protection, because of the microfissure caused by welding heat cycle.

• 한국근적외분광분석학회:학술대회논문집
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• 한국근적외분광분석학회 2001년도 NIR-2001
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• pp.1612-1612
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• 2001

The production of grain for export and domestic use is one of Australia's most important agricultural industries, and the NIR technique has been used extensively over many years for the routine monitoring of grain quality, particularly moisture and protein content. Because most Australian grain is intended for human food production, the determinants of grain quality for livestock feed, apart from protein, have been largely ignored. However the increasing use of grain for feeding to pigs, poultry, beef cattle and dairy cows has led to an important national research project entitled “Premium Grains for Livestock”. Two of the objectives of this project are to determine the compositional and functional characteristics of grains which influence their nutritional quality for the various classes of livestock, and to adopt rapid and objective analytical tests for these quality criteria. NIR has been used in this project firstly to identify a set of grain samples from a large population of breeders' lines which showed a wide spectral variation, and hence a potentially wide variation in nutritional value. The selected samples were not only subjected to an extensive array of chemical, physical and in vitro analyses, but also were grown out to produce sufficient quantities of grain to feed to animals in vivo studies. Additional grains were also strategically selected from farms in order to include the effect of weather damage, such as rain, drought and frost. In this study to date, NIR calibrations have been derived or attempted, on both ground and whole grains, for in vivo dry matter digestibility (DMD), pepsin-cellulase dry matter disappearance, protein, fat, acid detergent fibre, neutral detergent fibre, starch, in sacco DMD and in vitro assays to simulate starch digestion in the lumen and small intestine. Results so far indicate high calibration accuracy for chemical components (SECV 0.3 to 2.6%) and very promising statistics for in vivo DMD (SECV 1.8, $R^2$ 0.93, SD 7.0, range 61.9 to 92.3, n=60). There appears to be some potential for NIR to estimate some in vitro properties, depending upon the accuracy of reference methods and appropriate sample populations. Current work is in progress to extend the range of grains with in vivo DMD values (a very laborious and expensive process) and to increase the robustness of the various NIR calibrations, with the aim of implementing uniform testing procedures for nutritional value of grains throughout Australia.