Fabrication of anode supports for solid oxide fuel cells using nickel carbonate as a pore former

Seongtaek Park 한양대학교 세라믹연구소 2012 Journal of Ceramic Processing Research Vol.13 No.6

A method of fabricating NiO-YSZ (yttria stabilized zirconia) anode substrates was developed using a new pore former, i. e. nickel carbonate NiCO3 • 2Ni(OH)2 • 4H2O, which enables both the shrinkage and porosity, which must be compatible with the that of the electrolyte film and sufficient for the fuel supply and exhaust, respectively, to be easily tailored. In particular, the successful use of nickel carbonate as a pore former, instead of the previously used pore formers, such as graphite, carbon black, and polymer beads, suggests that other zirconium or nickel compound derivatives have the potential to be used as pore formers.

Processing, microstructure and mechanical properties of porous silicon nitride by a slip casting method using petroleum coke as pore former

Huan-Rui Wang,Ji-Qiang Gao,Fang-Li Yu,Yuan Li,Jian-Feng Yang 한양대학교 세라믹연구소 2009 Journal of Ceramic Processing Research Vol.10 No.6

In this study, porous Si3N4 ceramics were obtained by a slip casting method which would be easier applied in industry. The most stable and dispersing aqueous suspension was obtained from a solid slurry content of 56.2%, a carboxymethyl cellulose concentration of 0.3% as the adhesive and 0.05% glycerol as the defoamer. Petroleum coke was used as pore-former, and at the same time, it was helpful for the stability of the suspension. The burning-out of the petroleum coke seemed to be an economical way for increasing the porosity of porous Si3N4. After sintering at 1,800℃ for 2 h, samples with a pore size about 10 μm, porosities of 45-60%, and flexural strength of 52.0-112.1MPa were obtained. In this study, porous Si3N4 ceramics were obtained by a slip casting method which would be easier applied in industry. The most stable and dispersing aqueous suspension was obtained from a solid slurry content of 56.2%, a carboxymethyl cellulose concentration of 0.3% as the adhesive and 0.05% glycerol as the defoamer. Petroleum coke was used as pore-former, and at the same time, it was helpful for the stability of the suspension. The burning-out of the petroleum coke seemed to be an economical way for increasing the porosity of porous Si3N4. After sintering at 1,800℃ for 2 h, samples with a pore size about 10 μm, porosities of 45-60%, and flexural strength of 52.0-112.1MPa were obtained.

수열반응을 이용한 미생물 담체용 다공성 세라믹스의 제조

양성구,정승화,강종봉 한국세라믹학회 2003 한국세라믹학회지 Vol.40 No.12

비정질알루미나에 기공형성제를 첨가하여 성형하고 수열반응, 열처리 및 수세를 통해 pellet 형태의 다공성 세라믹 담체를 제조하였다. 기공형성제는 64, 222, 405 $\mu\textrm{m}$의 평균 입경을 가지는 활성탄, 폴리머와 무기염의 변화를 두었으며, 20$0^{\circ}C$에서 24시간동안 수열반응 한 다음 $650^{\circ}C$에서 5시간동안 열처리 및 8$0^{\circ}C$에서 48시간 동안 수세하고, 결정의 생성 및 변화, 기공률, 기공의 분포 및 압축 강도를 측정하였다. 수열반응 이후 활성탄이 첨가된 시편은 boehmite로의 상전이가 이루어졌으나, 기공형성제로 폴리머 및 무기염이 첨가된 시편은 수열 반응 시 비정질알루미나의 aquohydroxy complex gel의 형성을 방해하여 boehmite 결정성장 억제를 가져왔다 활성탄을 기공형성제로 첨가하여 제조한 시편의 경우, 70% 이상의 기공률과 40kgf/$\textrm{cm}^2$ 이상의 강도를 갖는 ${\gamma}$-알루미나의 담체를 제조할 수 있었다. Porous ceramics for microoganism carriers were prepared with amorphous alumina and pore formers by hydrothermal reaction, burn-out and wash-out method. Activated carbon with average size of 67,222, and 405 $\mu\textrm{m}$, organic polymer and inorganic salt were used as pore formers. Specimens were hydrothermally treated at 200$^{\circ}C$ for 24 h, heat-treated at 650$^{\circ}C$ for 5 h, and washed out at 80$^{\circ}C$ for 48 h. The formation of crystalline phase, porosity, pore size distribution and compressive strength were measured. The specimen with activated carbon was transformed to boehmite phase, but organic polymer and inorganic salt inhibited the aquohydroxoy complex gel and crystalline formation. The porous ceramics for microoganism carriers using activated carbon as a pore formers was successfully prepared, which is composed of ${\gamma}$-alumina phase with porosity of above 70 vol% and the compressive strength of 40 kgf/$\textrm{cm}^2$.

Design and Optimization of Solid Dispersed Osmotic Pump Tablets of Aceclofenac, A Better Approach to Treat Arthritis

( Sudeesh Edavalath ),( B Prakash Rao ) 한국약제학회 2011 Journal of Pharmaceutical Investigation Vol.41 No.4

The aim of this work was to prepare porous osmotic pump tablets for controlled delivery of Aceclofenac. Aceclofenac solid dispersion was prepared to improve the solubility by using the drug-carrier (Mannitol) ratio of 1:1. The osmotic pump tablets were prepared using the solid dispersed product of Aceclofenac. The formulation contains potassium chloride as osmotic agent, cellulose acetate as semipermeable membrane, poly ethylene glycol (PEG 4000) as pore former and sodium lauryl sulphate (SLS) as solubility enhancer. The formulations were designed by the general factors such as osmotic agent and pore former. All formulations were evaluated for various physical parameters and, the in vitro release studies were conducted as per USP. The drug release kinetic studies such as zero order, first order, and Higuchi and Korsmeyer peppas were determined and compared. All the formulations gave more controlled release compared to the marketed tablet studied. Numerical optimization techniques were applied to found out the best formulation by considering the parameter of in vitro drug release kinetics and dissolution profile standards. It was concluded that the porous osmotic pump tablets (F7) composed of Aceclofenac solid dispersion/Potassium chloride/Lactose/Sodium lauryl sulphate/Magnesium Stearate (400/40/95/10/5, mg/tab) and coating composition with Cellulose acetate/PEG 4000 (60/40 %w/w) is the most satisfactory formulation. The porous osmotic pump tablets provide prolonged, controlled, and gastrointestinal environment-independent drug release.

알루미나-아연붕규산염 유리를 이용한 저온 소결 다공성 세라믹스의 제조 및 특성

김관수,송기영,박상엽,김신,김성진,윤상옥,Kim, Kwan-Soo,Song, Ki-Young,Park, Sang-Yeup,Kim, Shin,Kim, Sung-Jin,Yoon, Sang-Ok 한국세라믹학회 2009 한국세라믹학회지 Vol.46 No.6

The low-temperature preparation of porous ceramics was carried out using mixtures of alumina-zinc borosilicate (ZBS) glass. The compositions of alumina-ZBS glass mixture with PMMA pore-former were unfortunately densified. Because PMMA was evaporated below the softening point of ZBS glass ($588{^{\circ}C}$), the densification through the pore-filling caused by the capillary force might occur. Howerver, those with carbon possessed pores where carbon was evaporated above the softening point. The porous ceramic having 35% porosity was successively fabricated by the low-temperature sintering process below $900{^{\circ}C}$ using 45 vol% of alumina, 45 vol% ZBS of glass, and 10 vol% of carbon as starting materials.

Effects of the Decomposition Residue of Compound Additive on Resintering Behavior

Kim, H.S.,Joung, C.Y.,Kim, S.H.,Na, S.H.,Lee, Y.W.,Sohn, D.S. 한국원자력학회 2002 Nuclear Engineering and Technology Vol.34 No.4

Oral lipid based multiparticulate pastilles: design and effect of pore former

Ashlesha P. Pandit,Ganesh Divase,Tushar Chavan,Kishanchandra Khandelwal 한국약제학회 2015 Journal of Pharmaceutical Investigation Vol.45 No.1

The purpose of this research work was todesign and develop droplet solidification apparatus for lipidbased pastilles. Oral lipid based multiparticulate pastillesof solid lipid glycerol monostearate were formulated tocontrol the release of highly water soluble drug metoprololsuccinate. The apparatus was optimized at 14G needle sizeand metallic surface base plate cooled at 4 ˚C. Pastilleswere evaluated for their size, shape, contact angle, density,flow properties, friability, crushing strength, drug content,thermal properties, in vitro and in vivo drug release. Pastilleswere hemispherical in shape of size 3.1–4.3 mm. Contact angle was found to be more than 120˚. Drugrelease was controlled for 8 h. Scanning electron microscopystudy revealed the smooth external surface with poresto ingress dissolution media to enhance the drug releaserate. Increased quantity of pore former enhanced the dissolutionrate. Other operating variables like contact angleand height of needle from base plate were found to affectthe size of pastilles. The dissolution of optimized batch ofpastilles was best fitted to first order kinetic model. In vivopharmacokinetic study showed correlation with in vitrodrug release profile.

기공전구체를 이용한 고체전해질 연료전지의 동시소성 연구

문지웅,이홍림,김구대,김재동,이해원 한국세라믹학회 1998 한국세라믹학회지 Vol.35 No.3

Unite cell of soid oxide fuel cell (SOFC) that consists of a dense yttria-stabilized zirconia(YSZ) electrolyte a porous nickel-YSZ cermet anode and a porous strontium- doped lanthanum manganate(LSM) cathod was fabricated from using pore former through co-firing technique. Initial sintering shrinkage rates of each layer were identified for fabricating SOFC. Heterogenous sintering was very effective in tailoring shrinkage rate for three layers. The powder tailoring necessary for shrinkage rate matching are as follows ; electrolyte of 60% TZ8YS/ 40% TZ8Y mixture anode of 51wt% NiO/49 wt% (70wt% TZ8YS/30 wt% UT ZrO2) mixture and cathode of 80% LSM/20% UT ZrO2 mixture . The overall sintering shrinkage rate differences of three layers using these compositions were maintained in a few percent.

폴리카프로락톤 매트릭스로부터 세파드록실의 방출에 미치는 BSA의 영향

김승렬,정연진,김영미,이치호,김대덕 한국약제학회 2004 Journal of Pharmaceutical Investigation Vol.34 No.5

In order to investigate the effect of bovine serum albumin (BSA), as a pore former, on the controlled release of an antibiotic from a biodegradable polymeric device, polycaprolactone (PCL)-cefadroxil matrices were prepared by the solvent casting method. The amount of cefadroxil released from various formulations at 37℃ was measured by HPLC. The duration of antimicrobial activity of matrices against S. aureus was evaluated by measuring the diameters of the inhibition zone. The morphology of the matrices was investigated by scanning electron microscopy (SEM). The release rate and extent of cefadroxil from PCL matrix increased as the loading dose and particle size of BSA/cefadroxil mixture powder increased. Cefadroxil released from the matrix exhibited antibacterial activity for up to 4 days. SEM of the cross-section of matrix showed the typical channel formation after 3 days of release study. Thus, a biodegradable polymeric matrix loaded with antibiotic/BSA mixture can effectively prevent bacterial infection on its surface, thereby bringing about an enhancement of biocompatibility of biomaterials.

Preparation of Porous YSZ Using SiO₂ as Pore Former

Hwang, Moon-Jin,Chung, Young-Min,Ju, Jeong-Hun,Bak, Yu-Rim,Lee, Young-Il,Jeong, Han-Mo,Chi, Ki-Whan,Park, Sang-Youn,Ryu, Kwang-Sun Korean Chemical Society 2010 Bulletin of the Korean Chemical Society Vol.31 No.10