3Y-TZP (3 mol% yttria-stabilized tetragonal zirconia polycrystals) ceramics have excellent mechanical properties including high fracture toughness, good abrasion resistance as well as chemical and biological stability. As a result, they are widely used in mechanical and medical components such as bearings, grinding balls, and hip implants. In addition, they provide excellent light transmittance, biocompatibility, and can match tooth color when used as a dental implant. Recently, given the materials’ resemblance to human teeth, these ceramics have emerged as an alternative to titanium implants. Since the introduction of CAD/CAM in the manufacture of ceramic implants, they’ve been increasingly used for prosthetic restoration where aesthetics and strength are required. In this study, to improve the surface roughness of zirconia implants, we modified the 3YTZP surface with a biocomposite of hydroxyapatite and forsterite using room temperature spray coating methods, and investigated the mixed effect of the two powders on the evolution of surface microstructure, i.e., coating thickness and roughness, and biological interaction during the in vitro test in SBF solution. We compared improvement in bioactivity by observing dissolution and re-precipitation on the specimen surface. From the results of in vitro testing in SBF solution, we confirmed improvement in the bioactivity of the 3Y-TZP substrate after surface modification with a biocomposite of hydroxyapatite and forsterite. Surface dissolution of the coating layer and the precipitation of new hydroxyapatite particles was observed on the modified surface, indicating the improvement in bioactivity of the zirconia substrate.

This study analyzed the chemical characteristics and physiological activity of five kinds of fresh vegetables produced in trees in early spring and tried to use them as basic data for wild vegetable producers and processed food manufacturers using wild vegetables. The crude protein, minerals, ascorbic acid, folate, total phenol, total flavonoid, DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging activity and ACE (angiotensin converting enzyme) inhibitory activity were determined. Five spring wild vegetables contain high protein and phosphorus, indicating that they are useful food ingredients as sources of protein and phosphorus. Vitamin C content was high in R. venicifera and C. sinensis shoots, and in particular, R. venicifera and A. cortex shoots have high folic acid (folate) contents of 1,903.91 ug% and 1,525.35 ug%, respectively, which is considered a good food for folic acid intake in spring. The total phenol content was between 0.52% and 1.27%, and it was the highest in C. sinensis of 1.27%, followed by the order of R. venicifera, A.cortex, K.pictus, and A. elata, which tended to be consistent with the total flavonoid content. As for DPPH radical scavenging ability, C. sinensis (55.93%) showed the highest activity, and ACE inhibitory activity showed the highest activity in A. cortex (88.04%).

Ramie (Boehmeria nivea M.) has been used for fiber materials in Korea traditionally, but in recent years, the concern with ramie leaves for the food industry such as tteok (a kind of Korean rice cake) industry has been increasing, so a study for eatable ramie is required for the expansion of ramie consumption. Moreover, the ramie varieties for the food industry are not established, so the natural species are cultivated in general; therefore, it is very important to select the ramie varieties for the food industry such as rice cakes, tea, beverage and so on. This study was undertaken to compare the physiochemical properties among 9 ramie lines selected in the Yeonggwang-gun Agricultural Technology Center to select the eatable ramie varieties for the food industry. The contents of the protein among 9 ramie lines was 6.21~7.56% and had the highest content in the YG55. The folic acid (folate) and vitamin C content had varying differences among the 9 lines; the content of folate showed 771.52~1,978.84 μg%, that of vitamin C showed 149.42~275.34 mg%. The ACE inhibitory activity appeared to be the highest in YG88 (21.5%) among the 9 ramie varieties tested.

This study was performed to determine the optimal time of harvest for ramie leaves with the two varieties (Seocheon Seobang and Seoncheon Baekpi) by comparison of physiological activity and physicochemical characteristics. The crude protein, minerals, ascorbic acid, folate, chlorophyll, ACE inhibitory activity and AChE inhibitory activity were determined. The amount of crude protein in ramie leaf, which was collected in Seocheon-gun, Chungcheongnam-do, grew up steadily from early May to September. The content of calcium in was higher in Baekpi than in Seobang. Seobang displayed its highest value of 3,569.90 mg% in September, while Baekpi displayed its highest value of 3,163.84 mg% in October. Although, folate and vitamin C contents in the two varieties were slightly different, they were higher as the growth date grew in October. The highest value of chlorophyll content was observed in October, which was later in the vegetative state. ACE inhibitory activity and AChE inhibitory activity appeared to be higher in Baekpi than in Seobang. Between June and August, ACE inhibitory activity was highest in Baekpi variety.

Odor emission factors (OEFs) are important parameters in characterizing odor sources, understanding emission patterns, designing abatement facilities, and providing appropriate control methods. In this study, OEFs for complex odor from grit removal chambers in publicly-owned wastewater treatment plants were determined, and the major operating conditions affecting the emission factors were investigated. In the main study site of “S” wastewater treatment plant, the averaged OEFs from the grit chamber were found to be 466.2, 162.6, and 54.7 OU/m2/min in summer, spring, and winter, respectively. OEFs from two other grit chambers in different wastewater plants were independently measured for comparison, and the values were in the same range as the OEF from S-site at a 95% confidence level. Nevertheless, the OEFs could differ depending on the types of wastewater and the sizes of wastewater treatment plants. Using the multi-variable linear regression method, correlations between OEFs and operating conditions, i.e. activities, from grit chambers were statistically analyzed. The analyses showed that operating conditions, including total suspended solids, water temperature, and temperature difference between water and air, were the most significant parameters affecting the OEF. A linear equation using these three parameters was proposed to estimate the OEF, and can be used to predict an OEF for another grit chamber, without odor measurement.

This study aimed to estimate the odor emission rate from swine nursery facilities (naturally and mechanically ventilated) using probability distribution. Odor occurrence trends in the study facilities were very different; odor concentration and gas flow had a lognormal distribution. Monte Carlo simulation was used to carry out the uncertainty analysis. Odor emission rate was found to range from 18.05 OU/sec (10th percentile) to 621.88 OU/ sec (90th percentile), and odor emission rate per head ranged from 0.02 OU/sec · head (10th percentile) to 0.64 OU/ sec · head (90th percentile).

본 연구에서는 황차를 모차로 증식 가능한 미생물(Eurotium cristatum)을 이용하여 발효시킨 발효차 (금화차)의 개발 가능성을 모색하고 품질특성을 분석하였다. 발효조건에 따른 금화차의 산도는 금화균 무첨가로 제조한 대조구는 1.89%, 금화균을 첨가하여 배양하지 않고 제조한 구는 1.85%, 금화균을 첨 가하여 2일간 배양한 시험구는 1.85%를 나타냈으며 5일간 배양한 시험구는 1.64%, 7일 이상 충분히 배 양한 시험구는 1.06%를 나타내어 금화균의 증식에 따라 산도는 감소되는 경향을 나타내었다. 금화차의 색도는 금화균을 첨가하여 발효를 진행 할수록 L(명도) 값이 낮아지고 a(적색) 값과 b(황색) 값은 높았 으며 실제로 우려낸 차의 색상도 어두워지는 경향을 나타냈다. 총 유리아미노산의 함량은 발효가 진행 될수록 감소하여 금화균에 의해 발효된 발효차는 대조구인 황차의 50% 이하였다. 유리아미노산 중에서 Theanine의 함량이 가장 높았고 그 다음은 Aspartic acid, Glutamic acid와 Arginine 등이 검출되었 다. 또한 발효조건에 따른 금화차 발효 중 카테킨, 카페인 및 테아플라빈 함량을 측정한 결과 발효가 종료된 금화차의 EGC의 함량이 215ppm으로 낮았고, 반면에 EC의 함량은 상대적으로 높았다. EGCG 함량은 금화균의 발효가 충분히 이루어진 실험구가 99ppm으로 가장 낮았고 다른 시험구는 300ppm 정 도로 측정되어 EGC와 마찬가지로 나머지 구들과 큰 차이를 보였다. 카페인 함량은 모든 구가 1,200 ppm으로 미생물 발효과정에 따른 차이가 관찰되지 않았고 테아플라빈 함량은 금화균 발효 후에는 약 400ppm으로 발효전보다 약 300ppm 낮았다.

Hydroxyapatite (HA) is well known as a biocompatible and bioactive material. HA has been practically applied as bone graft materials in a range of medical and dental fields. In this study, two types of dense hydroxyapatite ceramics were prepared from natural bones and synthetic materials. The biocompatibility of HA ceramics for supporting osteoblast cell growth and cytotoxicity using an in vitro MG-63 cell line model were respectively evaluated. Artificial hydroxyapatite shows relative density of 93% with 1-2 μm after sintering, but a hydroxyapatite compact derived from bovine bone has low sintered density of 85% with a small content of MgO. Irrespective of the starting raw materials, both types of sintered hydroxyapatite displayed similar biocompatibility in the tests. FE-SEM observations showed that most MG-63 cells had a stellar shape and formed an intercellular matrix containing fibers on sintered HA. The cells were well attached and grown over the HA surface, indicating that there was no toxicity.

본 연구는 하동지역의 녹차에 대해 근적외선 분광분석법(Near Infrared Spectroscopy, NIRS)을 이용하여 채취시기별 화학적 성분(총질소, 엽록소, 탄닌, 유리아미노산, 데아닌, 비타민 C, 카페인, 카테킨류, 총카테킨) 및 무기물 성분 변화에 대하여 분석하였다. 녹차의 화학적 성분 함량에 있어 엽록소, 탄닌, 비타민 C와 총카테킨 함량은 채취시기가 늦어질수록 증가한 반면, 총질소, 유리아미노산, 데아닌, 카페인 등은 대체로 감소하는 경향을 보였다. 무기물 함량은 채취시기가 늦어질수록 Mg, Ca, Mn은 증가하였으나 Na, K, B는 감소하였다. 또한 우전과 세작의 화학성분 중 총질소, 엽록소, 유리아미노산, 데아닌, 카페인, 총카테킨과 무기물 중 Na, Mg, Ca, B, Se 함량에 있어서는 차이를 나타내지 않았다.

We carried out basic study on the major odor substances from livestock waste treatment plant to design high efficiency offensive odor treatment facility. We choose Y and G-treatment plants and measured each samples from pre-treatment facility, water treatment facility, sludge treatment facility and offensive odor treatment facility. The odor was mainly produced from pre-treatment facility from above measurements. The concentration of hydrogen sulfide was very high as 1,200 ppm from impurity treatment facility. The concentration of hydrogen sulfide was detected as 100 ppm in waste water treatment facility(aeration facility and head) and 160∼252 ppm in sludgy treatment facility (retaining facility and scum tank). The offensive odor treatment facility was composed of washing tower using NaOCl as washing material and bio-filter. Efficiency of the offensive odor treatment facility on the hydrogen sulfide was 5∼33% and the efficiency on the ammonia was low except Y-treatment facility’s vortex mixer washing tower which is 98%. Reduction efficiency of hydrogen sulfide was increased from 14.7% to 96.3% by changing washing material, NaOH, at Y-treatment facility’s vortex mixer washing tower.

Geopolymer is a term covering a class of synthetic aluminosilicate materials with potential use in a number of areas, but mainly as a replacement for Portland cement. In this study, geopolymers with fly ash and meta kaolin were prepared using KOH as an alkali activator and water glass. The effect of water glass on the microstructures and the compressive strength of the geopolymer was investigated. As the amount of water glass increased, the dissolved inorganic binder particles in the geopolymers increased due to polymerization, resulting in a dense microstructure. The meta kaolin-based geopolymer showed a better extent of polymerization and densification than that of the fly ash-based geopolymer. XRD data also suggested that polymerization in meta kaolin-based geopolymers should be active resulting in the formation of an amorphous phase with an increasing amount of water glass. The compressive strength of the geopolymer was also dependent on the amount of water glass. The compressive strength of the geopolymers from both fly ash and meta kaolin increased with an increasing amount of water glass because water glass improved the extent of polymerization of the inorganic binder and resulted in a dense microstructure. However, the addition of water glass to the geopolymer did not seem to be effective for the improvement of compressive strength because the meta kaolin-based geopolymer mainly consisted of a clay component. For this reason, the fly ash-based geopolymer showed a higher value of compressive strength than the meta-kaolin geopolymer.

Geopolymer materials are attractive as inorganic binders due to their superior mechanical and eco-friendly properties. In the current study, geopolymer-based cement was prepared using aluminosilicate minerals from fly-ash with KOH as an alkaline-activator and Na2SiO3 as liquid glass. Then, calcium carbonate powder from a clam shell was mixed with the geopolymer and the mixture was coated on a concrete surface to provide points of attachment for environmental organisms to grow on the geopolymers. We investigated the effect of the shell powder grain size on the microstructure and bonding property of the geopolymers. A homogeneous geopolymer layer coated well on the concrete surface via aluminosilicate bonding, but the adhesiveness of the shell powder on the geopolymer cement was dependent on the grain size of the shell powder. Superior adhesive characteristics were shown in the shell powder of large grain size due to the deep penetration into the geopolymer by their large weight. This kind of coating can be applied to the adhesiveness of eco-materials on the surface of seaside or riverside blocks.