• 한국세라믹학회지
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• 제53권2호
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• pp.241-245
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• 2016

The purpose of this study was to investigate the bloating mechanism of artificial lightweight aggregates with different sizes (ESA, effective surface area). Aggregates were produced using hard clay, stone sludge, and a bloating agent in order to observe the effect of the gradation of the artificial lightweight aggregates. Kerosene and amorphous carbon were used as bloating agent. The particle size of the produced aggregate ranged from 3 mm to 9 mm. With regard to the amount of bloating agent to be used, 2 ~ 6 parts by weight were used. The specific gravity, absorption rate, and the type of aggregates produced by rapid sintering at $1075{\sim}1200^{\circ}C$ were determined. Microstructures were observed. When ESA had a value of 1 or below, kerosene, which has a high burning rate, was found to be advantageous for use as a bloating agent. When ESA had a value of 1 or above, carbon, which has a relatively low burning rate was found to be an advantageous bloating agent. It is thought that kerosene is more advantageous, as ESA decreases, for the production of aggregates having low water absorption rate.

• 재활간호학회지
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• 제18권1호
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• pp.20-28
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• 2015

Purpose: This study aimed to investigate the effects of Korean hand acupressure on pain and abdominal bloating of patients receiving laparoscopic surgery. Methods: This study was a quasi-experimental design using a nonequivalent control group pre-post test. The experimental group and the control group were 39 patients each who were hospitalized at gynecology ward of a hospital located in Gyeonggi-do. The experimental group received Korean hand acupressure therapy on the meridian point: A5, A6, H3, H7, I38 for 48 hours immediately after the surgery. Pain and abdominal bloating were measured at 5 times. Data were analyzed using SPSS/Win 18.0. Results: The experimental group showed lower pain score than the control group (p<.001). While there was no significant difference in abdominal bloating (p=.528), the time effect was significantly different (p<.001). Conclusion: The findings indicate that Korean hand acupressure reduces pain and abdominal bloating of laparoscopic surgery patients.

• 한국세라믹학회지
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• 제38권9호
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• pp.811-816
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• 2001

본 연구에서는 소각재와 첨가제가 인공 골재의 용융상 형성 및 경량화에 미치는 영향과 인공 경량골재의 발포기구에 관하여 연구하였다. 인공 경량 골재 실험은 점토를 주원료로 하였으며 소각재는 0∼30wt%를 첨가하였고, 첨가재는 $Na_2CO_3,\;CaCo_3,\;K_2CO_3,\;MgCO_3$와 소량의 폐오일을 사용하였다. 점토/소각재/첨가재계 인공 경량골재 실험 결과 $CaCO_3와\;MgCO_3$ 첨가는 용융상 형성을 촉진하였으며, $Na_2CO_3$는 용융상 형성뿐만 아니라 골재의 경량화에 영향을 주었다. 폐오일을 첨가제로 사용한 결과 0.5wt% 이상 첨가시 골재의 경량화에 영향을 주었다. 소각재는 첨가량이 증가할수록 골재의 용융상 형성이 증가하였으나, 소각재 10wt%, 폐오일 2wt%, 1200$^{\circ}$C 소성조건이 인공 골재의 발포 및 용융상 형성과 함께 급격한 가스발포에 의한 부피 팽창이 일어나며, 최종적으로 표면 및 내부에 치밀한 소결상이 형성되는 것을 알 수 있었다.

• 한국결정성장학회지
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• 제19권1호
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• pp.48-53
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• 2009

점토와 석분오니로 비중이 1 이하인 인공경량골재를 제조할 때 발포제와 융제의 종류 및 소성온도가 미세구조, 부피 비중 흐리고 흡수율에 미치는 영향을 분석하였다. 한 종류의 기포 발포제를 첨가한 경우 부피 비중 $0.5{\sim}1.0$, 흡수율 $41{\sim}110%$ 범위의 다공성 인공경량골재 제조가 가능하였으나 골재 외형이 거칠고 미세구조가 불균일하였다. 융제 된 발포제가 각각 한 종류씩만 첨가된 골재는 소성 중 시편이 폭발하여 표피층(shell)의 일부가 소실되었다. 발포제로서 진공오일외에 ${Fe_2}{O_3}$와 탄소를 복합 첨가할 경우 black core와 shell 구조가 잘 형성되어 균일한 미세구조론 나타내었다. 융제된 발포제가 복합적으로 첨가된 $1200^{\circ}C$ 소성체의 경우, 점토 및 석분오니로만 제조된 시편에 비해 부피비중이 67% 줄고 흡수율은 48배 증가하여 우수한 발포특성을 좌였다. 본 연구에서 제조된 복합 첨가 계열 시편은 부피비중 $0.5{\sim}1.0$, 흡수율 $50{\sim}125%$의 다양한 물성을 나타냈으며, 따라서 각종 분야에 적용할 수 있을 것으로 생각된다.

• 한국세라믹학회지
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• 제49권2호
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• pp.161-166
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• 2012

The temperature-rasing sintering method was used in this study to fabricate the aggregates of uniform pore size and distribution containing reject ash occurred in the thermal power plant. The spheric green aggregates made of reject ash were put into the box furnace of 800~$1000^{\circ}C$, heated with a heating rate of 5~$15^{\circ}C$/min to 1200~$1275^{\circ}C$, sintered for 10 min and then discharged out of the furnace to the room temperature. The input temperature, heating rate and sintering temperature increased the bloating phenomenon of the specimen, and the sintering temperature among them was the most effective factor. The aggregate manufactured at $1275^{\circ}C$ had the specific gravity of about 1.0 and water absorption of 1~2%, and the pores of 500~1,000 ${\mu}m$ were uniformly distributed across the whole specimen. Especially, the aggregates fabricated using the temperature-rasing sintering method in this study showed an excellent bloating properties and uniform microstructure without black core phenomenon which is typical for the bloated ceramics synthesized by direct sintering method.

• 동력기계공학회지
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• 제20권5호
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• pp.86-91
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• 2016

This paper is concerned chiefly with the method of porous foam manufacture using basalt stone powder sludge. The hydrogen peroxide($H_2O_2$) of bloating agent has lots of problems to manufacture porous lightweight aggregate due to fast reaction rate with cement or calcium hydroxide($Ca(OH)_2$). The $H_2O_2$ injecting method using nozzle for manufacturing porous lightweight aggregate is proposed, in this study. This method is to inject $H_2O_2$ at the pressure of 10 MPa on upper side of slurry mixing materials such as stone powder sludge and quick-lime(CaO) by injector. The specimen was dried in furnace at $100^{\circ}C$ for 1 hour and cured at ambient temperature for 30 days. We analyzed the characteristics including specific gravity and water absorption. The experiments were found that the porous foam has low specific gravity, high water absorption and uniform distribution of porous more than manufactured foam by general bloating methods.

• 한국세라믹학회지
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• 제35권6호
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• pp.575-582
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• 1998

Sutiability of Jungsan clay shale dolomite sludge Anyang feldspar and alumina as raw materials for light-weight porous ceramics was examined. In order to find optimum manufacturing conditions compositions heating temperatuers and heating times were varied and their effects on physical properties were measured and bloating mechanism was investigated. Jungsan clay seems suitable as raw material to make the light-weight constructional materials with 5wt% of ANyang feldspar and alumina added in calcined clay (800$^{\circ}C$) having bulk density of 0.45g/cm3 water absorption of 1.34% and compressive strength of 85kg/cm2 rapid-heated at 1200$^{\circ}C$ for 30min. It is suggested that bloating mechanism depends on the difference of tem-peratures between the inside and outside in specimen the remained gases in interstices can bloat by the li-quid phase of surface with high viscosity and gas pressure at elevated temperature.

• 한국결정성장학회지
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• 제21권3호
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• pp.129-135
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• 2011

제철공업에서 부산물로 발생되는 EAF(Electric Arc Furnace) dust는 유해한 철분 성분을 다량 함유하고 있어 환경파괴를 일으킬 위험이 있는 지정폐기물이다. EAF dust의 자원화를 위하여 석탄화력 발전소에서 발생되는 바닥재와 준설토에 EAF dust를 첨가하여 세라믹 다공체의 제조 가능성을 연구하였다. 또한 등유는 비교적 저온에서 발포기구에 작용하는 탄소(C)의 효과를 보기위해 첨가하였다. 혼합은 건식 공정으로 했으며, 소결 방법은 $1050^{\circ}C$부터 $1200^{\circ}C$까지 $50^{\circ}C$ 간격으로 10분간 직화소성 하였다. 소결된 시편의 비중, 흡수율 및 미세구조를 관찰한 결과, EAF dust는 시편 내의 발포 현상을 용이하게 하여 초경량 다공체 골재를 얻을 수 있었다. $1150{\sim}1200^{\circ}C$의 소결온도에서 10 wt% EAF dust를 첨가한 인공경량골재는 비중 1.0 g/$cm^3$ 이하의 초경량 인공 경량 골재를 만드는 것이 가능할 것으로 판단되었다.

• 한국결정성장학회지
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• 제23권4호
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• pp.201-206
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• 2013

화력발전소에서 배출되는 석탄 바닥재 및 잔사회는 재활용이 힘든 폐자원이어서 주로 매립 처분되고 있다. 본 연구에서는 국내 화력발전소에서 배출된 석탄 잔사회, 바닥재 그리고 준설토를 혼합하여 인공골재를 제조하고, 실험인자가 골재의 발포거동 및 물성에 미치는 영향을 분석하였다. 특히 미연탄소가 많이 포함되어 있는 잔사회에 대하여 하소 처리를 한 뒤, 인위적으로 활성탄소를 첨가함으로서 하소유무 및 활성탄소 첨가량이 인공골재의 발포특성에 미치는 영향을 조사하였다. 이를 위해 인공골재의 부피비중 및 흡수율 값을 시편의 미세구조 관찰 결과와 연계하여 고찰함으로서, 잔사회의 재활용율 제고에 일조하고자 하였다.

• 동력기계공학회지
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• 제17권2호
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• pp.108-113
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• 2013

In this study, lightweight aggregate was made from basalt stone powder sludge. Clay and glass powder were respectively added from 0 to 20 wt% and from 0 to 100 wt%. The glass powder helped to form glassy phase which trapped generating gas in the materials. $CaCO_3$ helping bloating process was added from 0 to 10 wt%. It was possible to produce lightweight aggregate at range from $1150^{\circ}C$ to $1200^{\circ}C$. The specimen was heated in furnace at 1100, 1150 and $1200^{\circ}C$ for 15 min, respectively, to sinter aggregates. Chemical composition of materials were determined, and characteristics were analyzed, including specific gravity, water absorption. Lightweight aggregate which was heated at $1200^{\circ}C$ had specific gravity of $0.53g/cm^3$, water absorption of 3.08%, and this value satisfied KS L 8551 standard.