• 한국건설순환자원학회논문집
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• 제8권2호
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• pp.190-197
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• 2020

본 연구에서는 페로니켈의 제련과정에서 발생하는 산업부산물인 페로니켈슬래그 미분말과 광물질혼화재료를 사용한 시멘트 경화체의 역학적 특성 및 내구성능을 평가하였다. 3성분계 시멘트 경화체의 수화열, 공극구조, 압축강도, 길이변화, 급속염화물 침투시험(RCPT), 동결융해 저항성을 평가하여 보통포틀랜드 시멘트와 비교하였다. 그 결과 페로니켈 슬래그 미분말 및 광물질 혼화재료를 사용한 3성분계 시멘트 경화체의 압축강도는 기준콘크리트에 비하여 낮은 강도발현을 하였으나, 알칼리 활성화제를 사용함에 따라 어느 정도 회복되는 것을 알 수 있었다. 페로니켈 슬래그를 사용한 시멘트 모르타르의 길이변화는 기준 시편보다 수축이 덜 발생하는 것으로 나타났다. 또한 페로니켈 슬래그 미분말을 사용한 경우 알칼리활성화제 사용유무에 관계없이 모두 ASTM C 1202에서 제시한 '매우 낮은' 영역의 값을 나타내었으며, 동결융해저항성 평가에서도 기준콘크리트에 비하여 아주 우수한 결과를 나타내었다.

• 한국수소및신에너지학회논문집
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• 제14권4호
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• pp.313-320
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• 2003

볼밀링법을 이용하여 타이타늄 스펀지와 칩 또는 스크랩으로부터 상온애서 직접 타이타늄 수소와 분말을 재조하는 실험을 행하였다. 실험결과 진공중에서 볼링을 행한 타이타늄 스펀지와 칩의 경우 24시간외 후 합금분말의 크기는 약 20 um 정도의 크기를 갖는 것을 확인하였다. 그러나 수소화 분위기에서 볼밀링을 행한 경우에 12시간 후 수소화분말의 입도는 0.1-0.2 um로 극히 미세한 합금 분말이 제조되었다. 수소분위기에서의 볼밀링에 의한 타이타늄 분말제조는 기존의 방법에 비해 열을 가하지 않고 타이타늄 수소화분말을 얻을 수 있다는 장점과 나노크기의 미세한 수소화 분말을 얻을 수 있음을 알 수 있었다.

• 한국식품영양학회지
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• 제20권4호
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• pp.406-413
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• 2007

LOHAS(Lifestyles Of Health And Sustainability) drinks were prepared by the addition of mulberry leaf powder(MLP) at various levels(0%, 5%, 10% and 20%). Their characteristics of the drinks were examined according to antioxidant activity and sensory evaluation. In the sensory evaluation, there was no significant difference between the control group(0% MLP group) and 5% MLP group for overall quality. For the proximate compositions of the LOHAS drinks, moisture, crude ash, crude protein and crude fat were all increased as the ratio of MLP increased. For the mineral contents, the amounts of calcium and magnesium were increased, but sodium, according to adding levels of MLP.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2012년도 춘계 학술논문 발표대회
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• pp.259-262
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• 2012

Recently, as the national policy of green growth is promoted, construction field also makes an effort to reduce CO₂ gas released when producing cement continuously. In other words, as the method solving environmental pollution and resources exhaustion, lots of mineral material compounds such as blast furnace slag powder which is industrial by-product, fly ash, red mud, etc. are examined to bo used as the substitute good of cement Therefore this study is to investigate the hardening characteristics of alumino-silicate inorganic binder using red-mud used as a accelerator of industrial by-product such as fly ash and blast furnace slag powder according to curing temperature. As a result, it is effective to use red-mud as the accelerator of inorganic binder with other additory accelerators.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2007년도 춘계학술논문 발표대회
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• pp.147-150
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• 2007

As recent buildings often use low-quality concrete materials, are constructed defectively, and are put in extreme environmental conditions, many of them show the shortening of life resulting from the corrosion of reinforcing rods by salt damage, carbonization, freezing and thawing, cracking. This in turn raises the cost of repair and maintenance, so it is required to extend the life of structures through enhancing the durability of concrete. In response to the demand, researches on high-durability concrete are being made actively focused on the maximum water-cement ratio, the maximum unit quantity, the minimum cover thickness, the addition of mineral admixtures, etc. With this background, the present study examined the basic physical properties of concrete containing admixtures for enhancing the durability of concrete.

• Applied Microscopy
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• 제52권
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• pp.12.1-12.8
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• 2022

The microstructure of diatom frustules found in mud sediments along the coast of Boryeong- city, South Korea, was observed using a scanning electron microscopy (SEM), and the constituent elements of diatoms were analyzed using energy-dispersive X-ray spectroscopy (EDS). Diatom frustules and clay minerals were present in the SEM images of the mud powder. High-magnification SEM images revealed that the surface of the frustules contained identically shaped circular pores, measuring 1 ㎛ in diameter, arranged at regular intervals. This study revealed that the diatom shell fragments in the mud powder ranged in size from 3 to 30 ㎛, with an average thickness of approximately 2.5 ㎛. The elements Si, Al, Fe, K, Na, Mg, and Ti were detected while analyzing the frustule constituents, with Si being the primary component with the highest content.

• Computers and Concrete
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• 제10권2호
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• pp.95-104
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• 2012

This study uses recycled green building materials based on a Taiwan-made recycled mineral admixture (including fly ash, slag, glass sand and rubber powder) as replacements for fine aggregates in concrete and tests the properties of the resulting mixtures. Fine aggregate contents of 5% and 10% were replaced by waste LCD glass sand and waste tire rubber powder, respectively. According to ACI concrete-mixture design, the above materials were mixed into lightweight aggregate concrete at a constant water-to-binder ratio (W/B = 0.4). Hardening (mechanical), non-destructive and durability tests were then performed at curing ages of 7, 28, 56 and 91 days and the engineering properties were studied. The results of these experiments showed that, although they vary with the type of recycling green building material added, the slumps of these admixtures meet design requirements. Lightweight aggregate yields better hardened properties than normal-weight concrete, indicating that green building materials can be successfully applied in lightweight aggregate concrete, enabling an increase in the use of green building materials, the improved utilization of waste resources, and environmental protection. In addition to representing an important part of a "sustainable cycle of development", green building materials represent a beneficial reutilization of waste resources.

• 한국식품영양학회지
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• 제29권6호
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• pp.978-984
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• 2016

Osteoporosis is a disease that often occurs in postmenopausal women. The purpose of this study was to examine the positive effects of Cheongukjang powder containing menaquinone-7 (MK-7) on bone health circulation in postmenopausal women. Fifty-six postmenopausal women were recruited into a randomised double-blind placebo-controlled trial. The participants were randomly assigned into two groups. For 12 weeks, one group received $800{\mu}g$ MK-7 in the form of Cheongukjang packs (CMK-7), and the other group received the same amount of identical-looking placebo packs containing barley meal for 12 weeks. Femoral bone mineral density (BMD), bone-specific alkaline phosphatase (ALP), deoxypyridinoline (DPD), osteocalcin (OSC), serum Ca, and serum P were measured at baseline (0 weeks) and 12 weeks. After 12 weeks in the CMK-7 group, it was found that BMD, serum Ca, and serum P had increased above the baseline (p<0.0001, p=0.0028, p<0.0001), whereas bone-specific ALP, DPD, and OSC had decreased below the baseline (p=0.0003, p<0.0001, p<0.0001). Therefore, MK-7 taken as Cheongukjang is expected to prevent osteoporosis in postmenopausal women.

• 한국세라믹학회지
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• 제52권3호
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• pp.192-196
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• 2015

Low soda alumina powder was fabricated using silica (${\alpha}$-quartz) as an agent for removing soda components in the alumina. Quartz powder 2 mm in size was added to aluminum hydroxide obtained through the Bayer process, and then the mixture was heated at various temperatures. Finally, the heat-treated powders were sieved for classification. In this study, the effects of the quartz amount and heating temperature on the mechanism of removing soda were examined. A minimum soda content of 0.005 wt% was observed at the conditions of 15 wt% quartz (based on $Al(OH)_3$ amount) heat-treated at $1600^{\circ}C$ for 8 h. The soda components, such as $Na_2O$, NaOH, and $Na_2CO_3$, in alumina were ionized and activated at high temperature, and this facilitated the reaction with quartz silica and alumina producing nepheline. The advantages of using quartz include low iron content and low cost in comparison with the conventional de-soda process using chamotte, another silicate mineral.

• Preventive Nutrition and Food Science
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• 제17권2호
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• pp.152-157
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• 2012

This study was performed to increase the availability of Sedum sarmentosum (Dolnamul) and to improve the nutraceutical value of rice cakes (sulgitteok). The contents of crude protein, mineral, dietary fiber, water holding capacity, and hardness significantly and directly increased with lyophilized sedum powder (SP). Pore ratio and expansion rate decreased in samples containing more than 10% SP compared to the control. In a sensory evaluation, a positive correlation was detected between overall acceptability and taste ($R^2$=0.99, p<0.01), and color ($R^2$=0.72, p<0.05). Total polyphenol contents of the SP-treated groups were significantly elevated, accompanied by an increase in radical scavenging ability estimated by the 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay. Replacing 10% of the rice powder with SP efficiently improved the antioxidant and nutritional values of sulgitteok as well as its the sensory quality.