• The Journal of the Petrological Society of Korea
• /
• v.18 no.1
• /
• pp.49-65
• /
• 2009

Endlessly, mankind has been pursuing its dream toward understanding and conquering our neighboring planet, Mars since Mars has been identified as a planet. After the development of advanced science and technology of human race in 1960, the Union of Soviet Socialist Republics (USSR) had initiated its dream toward Mars and finally at present mankind acquires numerous important clues of Mars through over forties of space programs toward Mars. Furthermore, mankind takes its effort in colonizing Mars within several decades. This manuscript introduces the history of space mission programs of Mars up to date and major scientific findings to understand the Mars.

• Journal of Animal Science and Technology
• /
• v.47 no.1
• /
• pp.115-132
• /
• 2005

This research was conducted to make suggestions for the promotion of research activities in the field of animal resources sciences, and we evaluated the research funding trend and the present status of research funding offered by KOSEF in this field. Comparative portion of the number of research projects and grants in this field to other fields has a tendency to be decreased year by year except recent few years. Researchers in this field have received more research funding from the group-based program than from the individual-based program. Also, they have received less money(per project) than did researchers in the fields of general agricultural sciences and other science and technology. Researchers in this field ranges from 43 to 51 years of age and showed 48 years of average age. It was found that researchers who has been funded in the field of animal resources sciences have showed tendency of publication of more articles to SCI journals in recent 5 years. The strong points of the animal resources of agricultural sciences field in South Korea include: lots of researchers, the establishment of research infra-structure, the excellence in research competitiveness and technology level. However, its weaknesses are: a lack of leadership in relevant societies and institutes, a predicted shortfall of researchers in the next generation and insufficient research productivity. The opportunities include: increasing the importance of the biotechnology industry, activating international cooperation researches and exploring the multitude of possible research areas to be studied. However, some concerns still exist, such as threats from developed countries for the government to open the agricultural market, the reduction of the number of full-time farms and intensification of needs for economic and social effects. The diverse actions and systems based upon the strongpoint, weakness, opportunity and threats above-mentioned are required to encourage research activities in the field of animal resources of agricultural sciences in Korea In addition, researchers in this fields would make an effort to keep pace with international society as well as domestic demands.

• Resources Recycling
• /
• v.29 no.2
• /
• pp.28-36
• /
• 2020

To enhance the recycling rate of wasted glass bottles toward recycled aggregates, the study would decide optimal comminution equipment based on the particle size distribution, aspect ratio and equipment energy analysis. The impact, compress and abrasion is type of generated force by comminution. So, hammer crusher, shredder, roll crusher and ball mill have been selected because they have characteristic which is each type of force. As a result of the particle size analysis of each product, only the shredder product satisfied concrete and asphalt aggregate quality standard condition. Also, as a result of aspect ratio analysis using Imaging software program (Image J, National institute of health), most of size fraction is confirmed under 1.6 value. It was confirmed that the product has low dangerousness and satisfying to shpage index. Also, the particle reduction ratio against input energy of shredder product was the most high. Therefore, we can decide that the optimal equipment which applicable for comminuting waste glass bottle in certain particle size under 10mm is shredder. The result of study will make contribution to increasing energy efficiency of comminution processing and competitiveness of product.

• Geomechanics and Engineering
• /
• v.33 no.2
• /
• pp.133-140
• /
• 2023

Soil erosion can cause scouring and failures of underwater structures, therefore, various soil improvement techniques are used to increase the soil erosion resistance. The microbially induced calcium carbonate precipitation (MICP) method is proposed to increase the erosion resistance, however, there are only limited experimental and numerical studies on the use of MICP treatment for improvement of surface erosion resistance. Therefore, this study investigates the improvement in surface erosion resistance of sands by MICP through laboratory experiments and numerical modeling. The surface erosion behaviors of coarse sands with various calcium carbonate contents were first investigated via the erosion function apparatus (EFA). The test results showed that MICP treatment increased the overall erosion resistance, and the contribution of the precipitated calcium carbonate to the erosion resistance and critical shear stress was quantified in relation to the calcium carbonate contents. Further, these surface erosion processes occurring in the EFA test were simulated through the coupled computational fluid dynamics (CFD) and discrete element method (DEM) with the cohesion bonding model to reflect the mineral precipitation effect. The simulation results were compared with the experimental results, and the developed CFD-DEM model with the cohesion bonding model well predicted the critical shear stress of MICP-treated sand. This work demonstrates that the MICP treatment is effective in improving soil erosion resistance, and the coupled CFD-DEM with a bonding model is a useful and promising tool to analyze the soil erosion behavior for MICP-treated sand at a particle scale.

• Resources Recycling
• /
• v.26 no.6
• /
• pp.10-19
• /
• 2017

It is studied the effect of crystal structure of domestic High-Ca limestones using absorbent for desulfurization on the grinding characteristics and dissolution rates in wet flue gas desulfurization process of domestic coal fired power plant. It compared the crystal structure, grinding work index and dissolution rates with 4 Limestones from Jecheon-Danyang with different crystal structure, and we found that grinding work index differ in crystal size and crystal structure of limestones : The lower the value of the grinding work index is, the higher the dissolution rates of limestones. Confirmed that we have important indicators of grinding characteristics for crystal structure with CaO content of limestones.

• Applied Chemistry
• /
• v.15 no.1
• /
• pp.33-36
• /
• 2011

A chemiluminescent method with gold nanoparticles for determination of vitamin C has been presented. Gold nanoparticles highly increased chemiluminescence intensity of lumimol-H₂O₂ system by its catalytic effect. The gold nanoparticles enhanced chemiluminescent method is applicable for the determination of an antioxidant such as vitamin C. When vitamin C was introduced to the lumimol system with gold nanoparticles, chemiluminescence intensity was reduced with the concentration of the added vitamin C. Low concentrated vitamin C solutions in the range of 1×10^-3-1×10^-9 M were produced reduced chemiluminescence intensity of lumimol-H₂O₂ with gold nanoparticles system.

• Resources Recycling
• /
• v.30 no.5
• /
• pp.17-24
• /
• 2021

Natural aggregate regular exploitation has led to environmental and resource depletion issues; consequently, construction waste has become an important raw material in the supply of aggregate smoothly. The recycled aggregate produced in the most of recycled aggregate processing company in Korea has a high adhesion ratio of cement paste and mortar, which affects the water absorption ratio and density. Therefore, the quality of recycled aggregate needs to be improved. In this study, we improved the quality of recycled aggregate through the use of a multistage separation ball mill. This ball mill has a sieve which protects the ball mix and improves the motion. Products produced by using multistage separation ball mill were compared with various quality standard for utilization as recycle aggregate. Finally, we confirmed that the multistage separation ball mill can efficiently separate cement paste and mortar from natural aggregate and that it is suitable for the production of recycled aggregates.

• Resources Recycling
• /
• v.17 no.5
• /
• pp.44-51
• /
• 2008

The removal of minor elements such as Na, Ca and Fe has been performed from domestic aluminum hydroxide of 99.7% purity with organic acids. Oxalic and citric acid were used as the leaching agent, respectively and aluminum hydroxides of different particle size were also employed for the purification with organic acid leaching. Fine grinding of aluminum hydroxide has been tested using ball mills and leaching characteristics of each element have also been examined in terms of leaching parameters such as temperature, acid concentration, and solid density. As a result, it was found that oxalic acid showed higher leaching efficiency than citric acid in the concentration range of 0.1 to 1.0 mole/l and leaching amount of each element was also increased with the acid concentration and reaction temperature. It was observed that about 45% of Na was leached out during ball milling process which implied that the majority of Na contained in aluminum hydroxide was water soluble compound.

• Resources Recycling
• /
• v.10 no.6
• /
• pp.29-34
• /
• 2001

Fly ash powders were refined and separated into fine and coarse size by multi-air classification, and each particle was used for synthesizing mullite and zeolite. Mullite was prepared by sintering the mixture of fine fly ash with mean size of 6.5 $\mu$m and $A1_2$$O_3$powder at above $1450^{\circ}C$. Zeolite was synthesized through hydrothermal reaction with coarse fly ash mean size of $56.3\mu$m in 3.5 M NaOH solution at $120^{\circ}C$. The whole range of particle size can be recycled through size classification into fine and coarse fractions, which are used for syntheses of inorganic materials.

• Resources Recycling
• /
• v.15 no.6 s.74
• /
• pp.16-24
• /
• 2006

In this study, the neutralization and dechlorination process of MWI(Municipal Waste Incinerator) fly ash with $H_2SO_4$ are investigated to recover HCI, which is delivered from the reaction of chloride in the ash and sulfuric acid. The coarse crystalline gypsum and fine impurity containing heavy metal are also separated by 500# wet screening followed by recrystallization of the dechlorinated ash mainly made of $CaSO_4$. As a results, Using 100g MWI fly ash and 85g cone. sulfuric acid as raw material, 52.6g hydrochloric acid with 35% assay and 116.9g crystalline gypsum with 98% or more assay are recovered. In this process, 7.85g fine impurity containing heavy metal and 2.65g coarse impurity are also separated.