• Journal of Korean Society of Environmental Engineers
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• v.30 no.2
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• pp.207-212
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• 2008

This study focused on shorten the period of the struvite crystal birth and development by adding seed materials. For this purpose, three different seed materials were selected: sand, anthracite and struvite. The experiments has been conducted to evaluate the effect of the particle size of the selected seed material on the struvite crystallization, and to study the mixing effect which can be expressed by the value of $G{\cdot}t_d$(the multiple of mean velocity gradient(G) and mixing time($t_d$)). It was observed in this study that the removal efficiency of ammonia nitrogen increased by 9%, 11%, and 20% for sand, anthracite, and struvite added as the seed material, respectivley. This indicated that the struvite crystallization efficiency had a close correlation with the specific surface area of the seed particle. It was found that when struvite was selected as the seed material, the struvite crystallization proceeded at lower $G{\cdot}t_d$ value as compared with other seed materials. This observation implied that the secondary crystal birth would be dominated in this reaction. It was concluded in this study that the particle size was not significant factor on the struvite crystallization, while the $G{\cdot}t_d$ value was a considerably important factor in terms of the theory of the struvite crystal birth.

• Journal of the Korean Ceramic Society
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• v.32 no.2
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• pp.147-154
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• 1995

Abnormal grain growth behavior of BaTiO3 ceramics with controlling of particle size distribution of calcined powder was investigated. The particle size distribution was controlled by changing the calcining temperature or by using of classification and regrinding process. With broadening of the normallized size distribution in calcined powder, it showeda normal grain growth behavior in sintered body due to an increase of volume fraction of seed grain in the calcined powder. It was supposed that the seed grains could easily contact each other for the rapid grain growth during sintering process and resulted in fast switching-over from abnormal to normal grain growth stage.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.30 no.4
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• pp.123-130
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• 2020

Nano seed incorporated in micro-sized 4BS (Tetrabasic lead Sulfate) seed was applied to the positive electrode active material and compared with Nano 4BS seed (NS). The dispersion of NS decreased due to the aggregation phenomenon, while the nano seed incorporated in micro-sized 4BS seed (INS) could confirm excellent dispersion. As the content of INS increased, the particle size of the active material became small and constant, which was confirmed through SEM and particle size analysis. The specific surface area for the reaction was increased and the high-rate discharge and lifetime characteristics were improved. In order to confirm the variation in particle size distribution in the plate manufacturing process, internal resistance and voltage were measured for 200 AGM lead-acid batteries, and it was confirmed that batteries quality variation decreased.

• Proceeding of EDISON Challenge
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• 2015.03a
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• pp.76-82
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• 2015

Active matter는 스스로 에너지를 가지고 움직이는 개체들이 서로 상호작용을 하여 집단적인 움직임을 보이는 물질이다. Rotational noise model은 반발 상호작용과 rotational noise를 가지고 있는 self-propelled particle로 active matter를 설명한다. 이 연구에서는 rotational noise model에서의 상 도표와 클러스터 형성을 알아보고 입자들의 집단적인 운동을 도와주거나 방해할 수 있는 leader 입자와 seed가 클러스터의 운동에 어떠한 영향을 주는지 알아본다.

• Journal of the Korean Wood Science and Technology
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• v.52 no.4
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• pp.363-374
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• 2024

Nyamplung (Calophyllum inophyllum L.) seeds, which account for 40% of the fruit, have been used as a raw material for biofuels, and the seed shells remaining after their extraction are wasted. In this study, we investigated the potential of waste Nyamplung seed shells in the form of pellets as a biomass energy resource. A completely randomized research design was implemented to evaluate the effects of torrefaction and heat treatment on the quality of produced pellets. Two observed treatments, namely, particle size (0.18-0.25, 0.25-0.43, and 0.43-0.84 mm) and torrefaction temperature (200℃, 225℃, and 250℃), were investigated. Our results showed that the calorific value of torrefied Nyamplung seed-shell pellets ranged from 4,245.60 to 4,528.00 cal/g, fulfilling the Indonesia Nasional Standard (≥ 4,000 cal/g). The quality of pellets were the best when produced from raw materials with a particle size of 0.18-0.25 mm and torrefaction temperature of 225℃. Thus, we concluded that waste Nyamplung seed shells are a good raw material for the production of pellets.

• Korean journal of food and cookery science
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• v.14 no.5
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• pp.584-588
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• 1998

Red pepper powders with variuos seed contents (0%, 10%, 20%) and particle sizes were stored at 0$^{\circ}C$, 20$^{\circ}C$, and 30$^{\circ}C$ for 90 days, and the changes in their characteristics were monitored. The initial moisture content was about 13%, and the powders were packed in 0.1 mm-thick polypropylene (PP) bags. Moisture content of each power remained constantly, so PP bags appeared to be effective to prevent moisture transmission. All the values of L＊, a＊ and b＊ were higher in fine particles than in coarse particles. Storage at 0$^{\circ}C$ did not change any color values, however, overall color values devreased apparently when stored at 30$^{\circ}C$ for 90 days. Capsanthin contents decreased gradually at all storage temperatures and more rapidly at higher temperature. The contents of capsaicinoids in fine particles (49∼59 mg%) were twic as much as those in coarse particles (15∼36 mg%), and they did not change throughout the storage.

• Journal of Biosystems Engineering
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• v.40 no.3
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• pp.212-223
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• 2015

Purpose: Physical properties of Detarium microcarpum seeds were investigated as a function of moisture content to explore the possibility of developing bulk handling and processing equipment. Methods: Seed size, surface area, and 1,000-seed weight were determined by measuring the three principal axes, measuring area on a graph paper, and counting and weighing seeds. Particle and bulk densities were determined using liquid displacement and weight in a measuring cylinder, respectively. Porosity was computed from particle and bulk densities. Roundness and sphericity were measured using shadowgraphs. Angle of repose and static and kinetic coefficients of friction were determined using the vertical cylindrical pipe method, an inclined plane, and a kinetic coefficient of friction apparatus. Results: In the moisture range of 8.2%-28.5% (db), the major, intermediate, and the minor axes increased from 2.95 to 3.21 cm, 1.85 to 2.61 cm, and 0.40 to 1.21 cm, respectively. Surface area, 1,000-seed weight, particle density, porosity, and angle of repose increased from 354.62 to $433.19cm^2$, 3.184 to 3.737 kg, 1060 to $1316kg/m^3$, and 30.0% to 53.1%, respectively, whereas bulk density decreased from 647.6 to $617.2kg/m^3$. Angle of repose increased from $13.9^{\circ}$ to $28.4^{\circ}$. Static and kinetic coefficients of friction varied between 0.096 and 0.638 on different structural surfaces. Conclusions: Arithmetic mean, geometric mean, and equivalent sphere effective diameters determined at the same moisture level were significantly different from each other, with the arithmetic mean diameter being greatest. Surface area, 1,000-seed weight, particle density, porosity, and angle of repose all increased linearly with moisture content. Bulk density decreased linearly with moisture content. The coefficients of friction had linear relationships with moisture content. The highest values of static and kinetic coefficients of friction were observed on galvanized steel and hessian fabric, respectively, whereas the lowest values were observed on fiberglass.

• Bulletin of the Korean Space Science Society
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• 2004.10b
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• pp.380-383
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• 2004

We study the two storm events of 1997: one in May that was accompanied by a relativistic electron event (REE) and the other in September, with a more profound Dst decrease, but with no significant flux increase of relativistic electrons. We find that a larger amount of seed electrons was present in the May event compared to that of the September storm, whereas the ULF (ultra low frequency) power was more enhanced and the particle spectrum was harder in the September event. Hence, we demonstrate that a larger storm does not necessarily produce more seed electrons and that the amount of seed electrons is an important factor in an actual increase in REE flux levels, while ULF can harden the particle spectra without causing an apparent REE.

• Journal of Powder Materials
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• v.20 no.1
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• pp.37-42
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• 2013

$YAG:Ce^{3+}$ phosphor powders were synthesized using a $Al_2O_3$ seed (average particle size: 5 ${\mu}m$) by the polymer solution route. PVA solution was added to the sol precursors consisting of the seed powder and metal nitrate salts for homogeneous mixing in atomic scale. All dried precursor gels were calcined at $500^{\circ}C$ and then heated at $1400^{\circ}C{\sim}1500^{\circ}C$ in $N_2/H_2$ atmosphere. The final powders were characterized by using XRD, SEM, PSA, PL and PKG test. All synthesized powders were crystallized to YAG phase without intermediate phases of YAM or YAP. The phosphor properties and morphologies of the synthesized powders were strongly dependent on the PVA content. Finally, the synthesized $YAG:Ce^{3+}$ phosphor powder heated at $1500^{\circ}C$, which is prepared from 12:1 PVA content and has an average particle size of 15 ${\mu}m$, showed similar phosphor properties to a commercial phosphor powder.

• Agricultural and Biosystems Engineering
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• v.6 no.2
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• pp.70-76
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• 2005

Seed, stem and sprout of F. tataricum were separately milled using the ultra fine mill under the same condition to investigate the effect of roasting or extruding on the particle size, microstructure and water solubility of dietary fiber. The mean particle size of MR (roasting) is increased in stem and sprout, and that of ME (extruding) is increased in seed, compared to that of control. The microscopic views of seed show that control has the spherical shape but ME the larger and irregular shape, and those of stem and sprout show that control has the needle like shape but ME more rounded shape. Water solubility index of ME is much higher than that of control or MR in seed, stem and sprout. It shows that seed, stem and sprout are damaged more in extruding than in roasting, and the starch and cell wall structure must be destroyed to change the water insoluble dietary fiber into the water soluble dietary fiber.