• 제목/요약/키워드: Metal Powder

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Other Processed Products, Monitoring and the Exposed Dose Assessment of Heavy Metal, the Illegal Compounds (기타가공품의 중금속, 부정유해물질 모니터링 및 노출량 평가)

  • Jang, Jin-Seob;Kwon, Mun-Ju;Kim, Meyong-Hee;Park, Jin-Soo;Lim, Soo-Sun;Kwon, Sung-Hee;Song, Sung-Min;Yeo, Eun-Young;Hong, Seong-Hee;Kim, Jung-Im;Om, Ae-Son
    • Journal of Food Hygiene and Safety
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    • v.30 no.1
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    • pp.35-42
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    • 2015
  • This study was performed for both evaluating the safety of other processed products and providing basic information for making the general standard for contaminants in the category of other processed products. We analyzed the contents of three heavy metals, thirty six anti-impotence drugs and their analogues, three anti-obesity drugs and their analogues, twenty eight steroid drugs and their analogues, collecting in Incheon Metropolitan City. Any illegal compound was not detected in those products. However the contents of lead, cadmium and mercury of those products were at the range of 0.001-13.390 mg/kg, 0.03-1.231 mg/kg and 0.001-0.650 mg/kg respectively. Because there are no standards of heavy metals against other processed products, we compared the analytical results with relevant standards of both S. Korea and foreign countries. As a result, two products exceeded the relevant standards of lead, and other two products exceeded the relevant standards of mercury. The relative hazards compared to PTWI of FAO/WHO (Codex), Seafoods-pajeonmix, Perilla seed powder exceeded PTWI standards 0.214. The compulsory standards of each food product are determined by the category of the products. Because there is no standard of heavy metals in the category of other processed products in S. Korea, any food products registered as other processed product by manufacturer are free with those standards. Abusing similar problems on the categorization of food products could cause consumers' health problem. To prevent these problems, detail regulations on the categorization of food products have to be introduced.

A Study on the Stability and Sludge Energy Efficiency Evaluation of Torrefied Wood Flour Natural Material Based Coagulant (반탄화목분 천연재료 혼합응집제의 안정성 및 슬러지 에너지화 가능성 평가에 관한 연구)

  • PARK, Hae Keum;KANG, Seog Goo
    • Journal of the Korean Wood Science and Technology
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    • v.48 no.3
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    • pp.271-282
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    • 2020
  • Sewage treatment plants are social infrastructure of cities. The sewage distribution rate in Korea is reaching 94% based on the sewage statistics based in the year of 2017. In Korean sewage treatment plants, use of PAC (Poly Aluminum Chloride) accounts for 58%. It contains a large amount of impurities (heavy metal) according to the quality standards, however, there have been insufficient efforts to reinforce the standards or technically improve the quality, which resulted in secondary pollution problems from injecting excessive coagulant. Also, the increase in the use of chemicals is leading to the increases in the annual amount of sewage sludge generated in 2017 and the need to reuse sludge. As such, this study aims to verify the possibility of reusing sludge by evaluating the stability of heavy metals based on the injection of coagulant mixture during water treatment which uses the torrefield wood powder and natural materials, and evaluating the sedimentation and heating value of sewage sludge. As a result of analyzing heavy metals (Cr, Fe, Zn, Cu, Cd, As, Pb, and Ni) from the coagulant mixture and PAC (10%), Cr, Cd, Pb, Ni, and Hg were not detected. As for Zn, while its concentration notified in the quality standards for drinking water is 3 mg/L, only a small amount of 0.007 mg/L was detected in the coagulant mixture. Maximum amounts of over double amounts of Fe, Cu, and As were found with PAC (10%) compared to the coagulant mixture. Also, an analysis of sludge sedimentation found that the coagulant mixture showed a better performance of up to double the speed of the conventional coagulant, PAC (10%). The dry-basis lower heating value of sewage sludge produced by injecting the coagulant mixture was 3,378 kcal/kg, while that of sewage sludge generated due to PAC (10%) was 3,171 kcal/kg; although both coagulants met the requirements to be used as auxiliary fuel at thermal power plants, the coagulant mixture developed in this study could secure heating values 200 kal/kg higher than the counterpart. Therefore, utilization of the coagulant mixture for water treatment rather than PAC (10%) is expected to be more environmentally stable and effective, as it helps generating sludge with better stability against heavy metals, having a faster sludge sedimentation, and higher heating value.

The Effect of Platelet Derived Growth Factor - BB Loaded Chitosan/Calcium Metaphosphate on Bone Regeneration (혈소판유래성장인자를 함유한 Chitosan/Calcium Metaphosphate의 골조직재생효과에 관한 연구)

  • Lee, Seung-Yeol;Seol, Yang-Jo;Lee, Yong-Moo;Lee, Ju-Yeon;Lee, Seung-Jin;Kim, Suk-Young;Ku, Young;Rhyu, In-Chul;Han, Soo-Boo;Choi, Sang-Mook;Chung, Chong-Pyoung
    • Journal of Periodontal and Implant Science
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    • v.31 no.1
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    • pp.1-23
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    • 2001
  • Chitosan is biodegradable natural polymer that has been demonstrated its ability to improve wound healing, and calcium metaphosphate(CMP) is a unique class of phosphate minerals having a polymeric structure. In this study, chitosan/CMP and platelet derived growth factor(PDGF-BB) loaded chitosan/CMP sponges were developed, and the effect of the sponges on bone regeneration and their possibility as scaffolds for bone formation by three-dimensional osteoblast culture were examined. PDGF-BB loaded chitosan/CMP sponges were prepared by freeze-drying of a mixture of chitosan solution and CMP powder, and soaking in a PDGF-BB solution. Fabricated sponge retained its 3-dimensional porous structure with $100-200\;{\mu}m$ pores. The release kinetics of PDGF-BB loaded onto the sponge were measured in vitro with $^{125}I-labeled$ PDGF-BB. In order to examine their possibility as scaffolds for bone formation, fetal rat calvarial osteoblastic cells were isolated, cultured, and seeded into the sponges. The cell-sponge constructs were cultured for 28 days. Cell proliferation, alkaline phosphatase activity were measured at 1, 7, 14 and 28 days, and histologic examination was performed. In order to examine the effect on the healing of bone defect, the sponges were implanted into rat calvarial defects. Rats were sacrificed 2 and 4 weeks after implantation and histologic and histomorphometrical examination were performed. An effective therapeutic concentration of PDGF-BB following a high initial burst release was maintained throughout the examination period. PDGF-BB loaded chitosan/CMP sponges supported the proliferation of seeded osteoblastic cells as well as their differentiation as indicated by high alkaline phosphatase activities. Histologic findings indicated that seeded osteoblastic cells well attached to sponge matrices and proliferated in a multi-layer fashion. In the experiments of implantation in rat calvarial defects, histologic and histomorphometric examination revealed that chitosan/CMP sponge promoted osseous healing as compared to controls. PDGF-BB loaded chitosan/CMP sponge further echanced bone regeneration. These results suggested that PDGF-BB loaded chitosan/CMP sponge was a feasable scaffolding material to grow osteoblast in a three-dimentional structure for transplantation into a site for bone regeneration.

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Preparation and Oxygen Permeation Properties of La0.07Sr0.3Co0.2Fe0.8O3-δ Membrane (La0.07Sr0.3Co0.2Fe0.8O3-δ 분리막의 제조 및 산소투과 특성)

  • Park, Jung Hoon;Kim, Jong Pyo;Baek, Il Hyun
    • Applied Chemistry for Engineering
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    • v.19 no.5
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    • pp.477-483
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    • 2008
  • $La_{0.7}Sr_{0.3}Co_{0.2}Fe_{0.8}O_{3-{\delta}$ oxide was synthesized by a citrate method and a typical dense membrane of perovskite oxide has been prepared using as-prepared powder by pressing and sintering at $1300^{\circ}C$. Precursor of $La_{0.7}Sr_{0.3}Co_{0.2}Fe_{0.8}O_{3-{\delta}$ prepared by citrate method was investigated by TGA and XRD. Metal-citrate complex in precursor was decomposed into perovskite oxide in the temperature range of $260{\sim}410^{\circ}C$ but XRD results showed $SrCO_3$ existed as impurity at less than $900^{\circ}C$. Electrical conductivity of membrane increased with increasing temperature but then decreased over $700^{\circ}C$ in air atmosphere ($Po_2=0.2atm$) and $600^{\circ}C$ in He atmosphere ($Po_2=0.01atm$) respectively due to oxygen loss from the crystal lattice. The oxygen permeation flux increased with increasing temperature and maximum oxygen permeation flux of $La_{0.7}Sr_{0.3}Co_{0.2}Fe_{0.8}O_{3-{\delta}$ membrane with 1.6 mm thickness was about $0.31cm^3/cm^2{\cdot}min$ at $950^{\circ}C$. The activation energy for oxygen permeation was 88.4 kJ/mol in the temperature range of $750{\sim}950^{\circ}C$. Perovskite structure of membrane was not changed after permeation test of 40 h and the membrane was stable without secondary phase change with 0.3 mol Sr addition.

Antibacterial, Antioxidant, and Antiaging Effects of the Ethanol Extract of Dolnamul (Sedum sarmentosum) and the Production of the Oil in Water Cream (돌나물(Sedum sarmentosum) 에탄올 추출물의 항균, 항산화, 항노화 효과와 수중유적형 크림의 제조)

  • Kim, Young Dae;Kim, Young Min;Mo, Eun Kyoung
    • Journal of the Society of Cosmetic Scientists of Korea
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    • v.43 no.3
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    • pp.211-221
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    • 2017
  • This study was performed to investigate the functional properties and characteristics of Dolnamul (Sedum sarmentosum) as a cosmetic ingredient. Lyophilized sedum powder was extracted with ethanol and stored at $-20^{\circ}C$ for the following experiments. Total polyphenol compounds of the ethanol extract of sedum (SE) was $27.98{\pm}0.34g/kg$(dry weight): epicatechin ($162.14{\pm}5.07mg/kg$), epigallocatechin ($55.99{\pm}2.49mg/kg$), and kaempferol ($47.96{\pm}3.02mg/kg$) were contained in the SE. The SE had organic radical scavenging capacity ($78.43{\pm}1.08%$) and metal reducing power (FRAP value $2.54{\pm}0.12$). FTC and TBARS assays confirmed that the SE inhibited the early stage of lipid peroxidation ($62.03{\pm}0.38%$) as well as the final stage of lipid peroxidation ($55.36{\pm}2.05%$), respectively. The SE (5 mg/mL, dry weight) was proved to have antibacterial effect on the growth of Propionibacterium acnes. The inhibitory percentages of the SE on elastase and collagenase activities were $38.94{\pm}7.09%$ and $78.94{\pm}2.49%$, respectively. Compare to the control group, the SE treated group induced an increase of Col3A1 expression and collagen production ($58.11{\pm}1.07%$). The oil in water emulsion (0.5% SE adding group) showed pH 6.88 and 1.47 g/mL of density. The hardness changes of the SE adding emulsions were not detected during the stored periods at various temperatures ($-20-45^{\circ}C$) for four weeks. It is considered that the SE has antibacterial, antioxidant, and antiaging activities.

A Novel Volumetric Method for Quantitation of Titanium Dioxide in Cosmetics (용량분석법을 이용한 화장품 중 티타늄옥사이드의 정량)

  • Kim, Young-So;Kim, Boo-Min;Park, Sang-Chul;Jeong, Hye-Jin;Chang, Ih-Seop
    • Journal of the Society of Cosmetic Scientists of Korea
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    • v.31 no.4 s.54
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    • pp.289-293
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    • 2005
  • Nowadays there are many sun protection cosmetics including organic or inorganic UV filter as an active ingredient. Chemically stable inorganic sunsEreen agents, usually metal oxides, we widely employed in high SPF products. Titanium dioxide is one of the most frequently used inorganic UV filters. It has been used as pigments for a long period of cosmetic history. With the development of micronization techniques, it becomes possible to incorporate titanium dioxide in sunscreen formulations without whitening effect and it becomes an important research topic. However, there are very few works related to quantitations of titanium dioxide in sunscreen products. In this research, we analyzed amounts of titanium dioxide in sunscreen cosmetics by adapting redof titration, reduction of Ti(IV) to Ti(III) and reoxidation to Ti(IV). After calcification of other organic ingredients of cosmetics, titanium dioxide is dissolved by hot sulfuric acid. The dissolved Ti(IV) is reduced to the Ti(III) by adding aluminum metals. The reduced Ti(III) is titrated against a standard oxidizing agent, Fe(III) (ammonium iron(III) sulfate), with potassium thiocyanate as an indicator In order to test accuracy and applicability of the proposed method, we analyzed the amounts of titanium dioxide in four types of sunscreen cosmetics, such as cream, make-up base, foundation and powder, after adding known amounts of titanium dioxide $(1{\sim}25w/w%)$. The percent recoveries of the titanium dioxide in four types of formulations were in the range between 96 and 105%. We also analyzed 7 commercial cosmetic products labeled titanium dioxide as an ingredient and compared the results with those of obtained from ICP-AES (Inductively Coupled Plasma-Atomic Emission Spectrometry), one of the most powerful atomic analysis techniques. The results showed that the titrated amounts were well coincided with the analyzed amounts of titanium dioxide by ICP-AES. Although instrumental analytical methods, ICP-MS (Inductively Coupled Plasma-Mass Spectrometry) and ICP-AES, are the best for the analysis of titanium, it is hard to adopt because of their high prices for small cosmetic companies. It was found that the volumetric method presented here gat e quantitative and reliable results with routine lab-wares and chemicals.

Decomposition of Eco-friendly Liquid Propellants over Platinum/Hexaaluminate Pellet Catalysts (백금/헥사알루미네이트 펠렛 촉매를 이용한 친환경 액체 추진제 분해)

  • Jo, Hyeonmin;You, Dalsan;Kim, Munjeong;Woo, Jaegyu;Jung, Kyeong Youl;Jo, Young Min;Jeon, Jong-Ki
    • Clean Technology
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    • v.24 no.4
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    • pp.371-379
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    • 2018
  • The objective of this study is to develop a platinum/hexaaluminate pellet catalyst for the decomposition of eco-friendly liquid propellant. Pellet catalysts using hexaaluminate prepared by ultrasonic spray pyrolysis as a support and platinum as an active metal were prepared by two methods. In the case of the pellet catalyst formed by loading the platinum precursor onto the hexaaluminate powder and then adding the binder (M1 method catalyst), the mesopores were well developed in the catalyst after calcination at $550^{\circ}C$. However, when this catalyst was calcined at $1,200^{\circ}C$, the mesopores almost collapsed and only a few macropores existed. On the other hand, in the case of a catalyst in which platinum was supported on pellets after the pellet was produced by extrusion of hexaaluminate (M2 method catalyst), the surface area and the mesopores were well maintained even after calcination at $1,200^{\circ}C$. Also, the catalyst prepared by the M2 method showed better heat resistance in terms of platinum dispersion. The effects of preparation method and calcination temperature of Pt/hexaaluminate pellet catalysts on the decomposition of liquid propellant composed mainly of ammonium dinitramide (ADN) or hydroxyl ammonium nitrate (HAN) were investigated. It was confirmed that the decomposition onset temperature during the decomposition of ADN- or HAN- based liquid propellant could be reduced significantly by using Pt/hexaaluminate pellet catalysts. Especially, in the case of the catalyst prepared by the M2 method, the decomposition onset temperature did not show a large change even when the calcination temperature was raised at $1,200^{\circ}C$. Therefore, it was confirmed that Pt/ hexaaluminate pellet catalyst prepared by M2 method has heat resistance and potential as a catalyst for the decomposition of the eco-friendly liquid propellants.

Nanoscale Pattern Formation of Li2CO3 for Lithium-Ion Battery Anode Material by Pattern Transfer Printing (패턴전사 프린팅을 활용한 리튬이온 배터리 양극 기초소재 Li2CO3의 나노스케일 패턴화 방법)

  • Kang, Young Lim;Park, Tae Wan;Park, Eun-Soo;Lee, Junghoon;Wang, Jei-Pil;Park, Woon Ik
    • Journal of the Microelectronics and Packaging Society
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    • v.27 no.4
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    • pp.83-89
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    • 2020
  • For the past few decades, as part of efforts to protect the environment where fossil fuels, which have been a key energy resource for mankind, are becoming increasingly depleted and pollution due to industrial development, ecofriendly secondary batteries, hydrogen generating energy devices, energy storage systems, and many other new energy technologies are being developed. Among them, the lithium-ion battery (LIB) is considered to be a next-generation energy device suitable for application as a large-capacity battery and capable of industrial application due to its high energy density and long lifespan. However, considering the growing battery market such as eco-friendly electric vehicles and drones, it is expected that a large amount of battery waste will spill out from some point due to the end of life. In order to prepare for this situation, development of a process for recovering lithium and various valuable metals from waste batteries is required, and at the same time, a plan to recycle them is socially required. In this study, we introduce a nanoscale pattern transfer printing (NTP) process of Li2CO3, a representative anode material for lithium ion batteries, one of the strategic materials for recycling waste batteries. First, Li2CO3 powder was formed by pressing in a vacuum, and a 3-inch sputter target for very pure Li2CO3 thin film deposition was successfully produced through high-temperature sintering. The target was mounted on a sputtering device, and a well-ordered Li2CO3 line pattern with a width of 250 nm was successfully obtained on the Si substrate using the NTP process. In addition, based on the nTP method, the periodic Li2CO3 line patterns were formed on the surfaces of metal, glass, flexible polymer substrates, and even curved goggles. These results are expected to be applied to the thin films of various functional materials used in battery devices in the future, and is also expected to be particularly helpful in improving the performance of lithium-ion battery devices on various substrates.

A Review on the Recycling of the Concrete Waste Generate from the Decommissioning of Nuclear Power Plants (원전 해체 콘크리트 폐기물의 재활용에 대한 고찰)

  • Jeon, Ji-Hun;Lee, Woo-Chun;Lee, Sang-Woo;Kim, Soon-Oh
    • Economic and Environmental Geology
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    • v.54 no.2
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    • pp.285-297
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    • 2021
  • Globally, nuclear-decommissioning facilities have been increased in number, and thereby hundreds of thousands of wastes, such as concrete, soil, and metal, have been generated. For this reason, there have been numerous efforts and researches on the development of technology for volume reduction and recycling of solid radioactive wastes, and this study reviewed and examined thoroughly such previous studies. The waste concrete powder is rehydrated by other processes such as grinding and sintering, and the processes rendered aluminate (C3A), C4AF, C3S, and ��-C2S, which are the significant compounds controlling the hydration reaction of concrete and the compressive strength of the solidified matrix. The review of the previous studies confirmed that waste concretes could be used as recycling cement, but there remain problems with the decreasing strength of solidified matrix due to mingling with aggregates. There have been further efforts to improve the performance of recycling concrete via mixing with reactive agents using industrial by-products, such as blast furnace slag and fly ash. As a result, the compressive strength of the solidified matrix was proved to be enhanced. On the contrary, there have been few kinds of researches on manufacturing recycled concretes using soil wastes. Illite and zeolite in soil waste show the high adsorption capacity on radioactive nuclides, and they can be recycled as solidification agents. If the soil wastes are recycled as much as possible, the volume of wastes generated from the decommissioning of nuclear power plants (NPPs) is not only significantly reduced, but collateral benefits also are received because radioactive wastes are safely disposed of by solidification agents made from such soil wastes. Thus, it is required to study the production of non-sintered cement using clay minerals in soil wastes. This paper reviewed related domestic and foreign researches to consider the sustainable recycling of concrete waste from NPPs as recycling cement and utilizing clay minerals in soil waste to produce unsintered cement.

A study on γ-Al2O3 Catalyst for N2O Decomposition (N2O 분해를 위한 γ-Al2O3 촉매에 관한 연구)

  • Eun-Han Lee;Tae-Woo Kim;Segi Byun;Doo-Won Seo;Hyo-Jung Hwang;Jueun Baek;Eui-Soon Jeong;Hansung Kim;Shin-Kun Ryi
    • Clean Technology
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    • v.29 no.2
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    • pp.126-134
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    • 2023
  • Direct catalytic decomposition is a promising method for controlling the emission of nitrous oxide (N2O) from the semiconductor and display industries. In this study, a γ-Al2O3 catalyst was developed to reduce N2O emissions by a catalytic decomposition reaction. The γ-Al2O3 catalyst was prepared by an extrusion method using boehmite powder, and a N2O decomposition test was performed using a catalyst reactor that was approximately 25.4 mm (1 in) in diameter packed with approximately 5 mm of catalysts. The N2O decomposition tests were carried out with approximately 1% N2O at 550 to 750 ℃, an ambient pressure, and a GHSV=1800-2000 h-1. To confirm the N2O decomposition properties and the effect of O2 and steam on the N2O decomposition, nitrogen, air, and air and steam were used as atmospheric gases. The catalytic decomposition tests showed that the 1% N2O had almost completely disappeared at 700 ℃ in an N2 atmosphere. However, air and steam decreased the conversion rate drastically. The long term stability test carried out under an N2 atmosphere at 700 ℃ for 350 h showed that the N2O conversion rate remained very stable, confirming no catalytic activity changes. From the results of the N2O decomposition tests and long-term stability test, it is expected that the prepared γ-Al2O3 catalyst can be used to reduce N2O emissions from several industries including the semiconductor, display, and nitric acid manufacturing industry.