• Journal of the Korean Institute of Gas
• /
• v.15 no.4
• /
• pp.7-14
• /
• 2011

Using 20 L spherical explosion vessel and differential scanning calorimeter (DSC), an experimental investigation was carried on explosion characteristics and thermal decomposition of some reactive organic dust. As the result, the minimum explosion concentration of Benzoyl peroxide (BPO), Phthalic anhydride (PA) and 1-Hydroxybenzotriazol (HBT) exist between 10 and 15 g/$m^3$, which indicates that their explosion sensitivity are high. The maximum Kst values of HBT, PA and 97 % BPO are 251, 146 and 80 [$bar{\cdot}m/s$], respectively and the explosion severity of HBT is the explosion class of St-2. The flame velocity was also calculated from the combustion time of dust and flame arrival time to estimate the flame propagation characteristics in a closed vessel. The decomposition temperature and heat of decomposition reaction for 97 % BPO and HBT are $107^{\circ}C$ (1025 J/g), $214^{\circ}C$ (1666 J/g), respectively and it was found that these low decomposition temperature and high released heat affect the explosion characteristics.

• Journal of the Korean Wood Science and Technology
• /
• v.39 no.3
• /
• pp.230-237
• /
• 2011

The study was performed to investigate the characteristics of charcoal and temperature change of a kiln's inner and outer walls in carbonization process using improved kiln. In this kiln system, carbonization process was completed in eight days. In the kiln, the ignition temperature was kept about $720^{\circ}C$. And then the temperature were increased gradually prior to be refined. Finally, the temperature in refining process was reached to maximum point, $1,000^{\circ}C$. In the chimney, the temperature was increased gradually from $90^{\circ}C$ at ignition to $750^{\circ}C$ at refining. The temperature change of the kiln wall resembles a temperature change progress curve during a carbonization process. The highest temperature of the kiln wall that appeared by a carbonization process was around $500^{\circ}C$. As a result of having measured an inner wall and the outer wall of the kiln using an infrared thermography camera, it was judged with there being considerable latent heat on kiln wall and ceiling. Fixed carbon contented of charcoal was 85.9~89.9%. Refining degree of charcoal, hardness, calorific value and pH were l, 12, 7,047~7,456 kcal/kg, 9.0~9.9, respectively. The yield of wood charcoal was 13.8%, and compared to conventional kiln's yield increased 1.5%.

• Journal of the Korean Chemical Society
• /
• v.40 no.12
• /
• pp.724-732
• /
• 1996

The organic precipitate flotation using Cu(II)-pyrrolidinedithiocarbamate complex as a coprecipitant was studied for the preconcentration and determination of trace Cd, Pb, Bi and Co in several water samples. Experimental conditions such as pH of solution, amounts of Cu(II) and ammonium pyrrolidinedithiocarbamate(APDC), stirring time, the type and amount of surfactant, etc. were optimized for the effective flotation of analytes. After 3.0 mL of 1,000 ${\mu}g/mL$ Cu(II) solution was added to 1.00 L water sample, the pH of the solution was adjusted to 2.5 with HNO3 solution. Trace amounts of analytes were coprecipitated by adding 2.0% APDC solution. And the precipitates were flotated onto the surface of solution with the aid of nitrogen gas and sodium lauryl sulfate. The floats were collected from mother liquor, and filtered through the micropore glass filter by suction. The precipitates were dissolved with 4 mL conc. HNO3, and then diluted to 25.00 mL with deionized water. The analytes were determined by graphite furnace atomic absorption spectrophotometry. This flotation technique was applied to the analysis of some water samples, and the 90 to 120% of recoveries were obtained from the spiked samples, this procedure could be concluded to be simple and applicable for the trace element analysis in various kinds of water.

• Resources Recycling
• /
• v.13 no.4
• /
• pp.23-31
• /
• 2004

Basic studies have been conducted regarding the attempt of the utilization of waste Undaria pinnatifida as an adsorbent for the adsorption treatment of lead-containing wastewater. Undaria pinnatifida was found to be chiefly composed of hyo-carbonaceous compounds and have a fairly high specific surface area, which suggesting the possibility of its application as a Potential adsorbent. The electrokinetic Potential of Undaria pinnatifida particles was observed to be negatively highest at around pH 8 and the fact that its electrokinetic potentials are negative at the whole pH range supported it might be an efficient adsorbent especially for cationic adsorbates. Under the experimental conditions, $Pb^{2+}$ was found to mostly adsorb onto Undaria pinnatifida within a few minutes and reach the equilibrium in adsorption within ca. 30 minutes. The adsorption of $Pb^{2+}$ was exothermic and explained well by e Freundlich model. Acidic pretreatment of Undaria pinnatifida enhanced its adsorption capacity for $Pb^{2+}$ , however, the reverse was observed for alkaline pretreatment. The formation of organometallic complex between $Pb^{2+}$ and some functional groups on the surface of Undaria pinnatifida was considered to be one of the main drives for adsorption. Finally the adsorbability of$ Pb^{2+}$ was examined to be rather affected by several solution features such as the coexistence of other adsorbate, the variation of ionic strength, and the concentration of complexing agent.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.20 no.2
• /
• pp.443-450
• /
• 2019

We studied to find the optimal manufacturing conditions of coffee grounds sludge RDF with oil drying method. We expanded the lab scale to pilot scale to compare the efficiency of the oil-drying equipment and The selection of the ratio of coffee grounds and oil, the setting temperature, and the temperature change and water content with time were measured. In order to analyze the characteristics of the research results, characteristics of solid fuels produced(Coffee grounds of oil-dried) by calorimeter, TGA, combustion equipment, and combustion gas measuring instrument were analyzed. As a result, the ratio of oil to coffee grounds was 4: 1, and when the setting temperature was set to $300^{\circ}C$, the water content reached 10wt.% or less within 20 minutes. ln addition, it showed high calorific value of 6,273kcal/kg. However, coffee grounds had a similar composition to wood and showed high luminance and produced a lot of CO in combustion gas. As a result, it is considered to be unsuitable for thermoelectric power plant and camping fuel, but the initial ignition speed is high and the heat generation is high, so it is considered that it can replace the fuels for current use.

• Investigative Magnetic Resonance Imaging
• /
• v.10 no.1
• /
• pp.20-25
• /
• 2006

Purpose : To evaluate the NMR relaxation properties of newly developed high performance paramagnetic complexes. Materials and methods : 4-aminomethylcyclohexane carboxylic acid (0.63g, 4 mmol) was mixed with the suspension solution of DMF (15mL) and DTPA-bis-anhydride (0.71g, 2 mmol) to synthesize the ligand. The ligand was then mixed with Gd2O3 (0.18g, 0.5 mmol) to synthesize Gd-chelate. For the measurement of magnetic relaxivity of paramagnetic compounds, the compounds were diluted to 1mM and then the relaxation times were measured at 1.5T(64 MHz). Inversion-recovery pulse sequence was employed for T1 relaxation measurement and CPMG(Carr-Purcell-Meiboon-Gill) pulse sequence was employed for T2 relaxation measurement. Using MATLAB(Version 7.1) program, T1 magnetic relaxation map, R1 map, T2 magnetic relaxation map and R2 map were developed to represent magnetic relaxation time and magnetic relaxivity as image. Results : Compared to $R1=4.9mM^{-1}sec^{-1}$ and $R2=4.8mM^{-1}sec^{-1}$ of Omniscan (Gadodiamide), which is commercially available paramagnetic MR agent, R1 of SUK090(Gd-C32H74N5O24) was $12.46mM^{-1}sec^{-1}$ and R1 of SUK091(Gd-C34H78N5O24) was $12.77mM^{-1}sec^{-1}$. However, R1 of SUK092(Gd-C30H56N5O17) was decreased to $2.09mM^{-1}sec^{-1}$. In case of R2, SUK090(Gd-C32H74N5O24) was $8.76mM^{-1}sec^{-1}$ and SUK091(Gd-C34H78N5O24) was $7.60mM^{-}1sec^{-1}$ whereas SUK092(Gd-C30H56N5O17) was decreased to $1.82mM^{-1}sec^{-1}$. Conclusion : Among three new paramagnetic complexes, SUK090(Gd-C32H74N5O24) and SUK091(Gd-C34H78N5O24) showed higher T1, T2 magnetic relaxation rates than that of commercially available paramagnetic MR agent and thus expected to have more contrast enhancement effect.

• The Korean Journal of Nuclear Medicine
• /
• v.32 no.6
• /
• pp.516-524
• /
• 1998

Purpose: Radiolabeled CEA79.4 antibody has a possibility to be used in radioimmunoscintigraphy or radioimmunotherapy of cancer. We investigated the in vitro properties and biodistribution of CEA79.4 antibody labeled with Re-188 or Tc-99m. Materials and Methods: CEA79.4 was reduced by 2-mercaptoethanol to produce-SH residue, and was labeled with Re-188 or Tc-99m. For direct labeling of Tc-99m, methylene-diphosphonate was used as transchelating agent. CEA79.4 in 50 mM Acetate Buffered Saline (ABS, pH 5.3) was labeled with Re-188, using stannous tartrate as reducing agent. In order to measure immunoreactivity and the affinity constant of radiolabeled antibody, cell binding assay and Scatchard analysis using human colon cancer cells SNU-C4, were performed. Biodistribution study of labeled CEA79.4 was carried out at 1, 14 and 24 hr in ICR mice. Results: Labeling efficiencies of Tc-99m and Re-188 labeled antibodies were $92.4{\pm}5.9%$ and $84.7{\pm}4.6%$, respectively, In vitro stability of Tc-99m-CEA79.4 in human serum was higher than Re-188-CEA79.4. Immunoreactivity and affinity constant of Tc-99m-CEA79.4 were 59.2% and $6.59{\times}10^9\;M^{-1}$, respectively, while those of Re-188-CEA79.4 were 41.6% and $4.2{\times}10^9\;M^{-1}$, respectively. After 24 hr of administrations of Re-188 and Tc-99m labeled antibody, the remaining antibodies in blood were 6.32 and 9.35% ID/g respectively. The biodistribution of each labeled antibody in other organs was similar because they did not accumulate in non-targeted organs. Conclusion: In vitro properties and biodistribution of Re-188-CEA79.4 were similar to those of Tc-99m-CEA79.4. It appears that Re-188-CEA79.4 can be used as a suitable agent for radioimmunotheraphy.

• Journal of Bio-Environment Control
• /
• v.8 no.2
• /
• pp.75-82
• /
• 1999

This study was carried out to examine the effect of day/nignt temperatures during seedling culture on the vegetative and reproductive growth of Lycopersicum esculentum ‘Seokwang’. The study was consisted of two culture stages, plug seedling production in the growth chamber and hydroponic culture of the plant in a glasshouse. Experiments were replicated over time. The germinated seedlings were raised for 33 days (experiment 1) and 35 days (experiment 2) in 4 growth chambers, each with day/night temperatures of either $25^{\circ}C$/$25^{\circ}C$, 16$^{\circ}C$/16$^{\circ}C$, 16$^{\circ}C$/$25^{\circ}C$ or $25^{\circ}C$/16$^{\circ}C$. Cool-white fluorescent lamps provided 140$\mu$mol.m$^{-2}$ .s$^{-1}$ light for 12h each day. In the second experiment, all chambers were supplied with 1000$\mu$mol.mol$^{-1}$ CO$_{2}$ during the photoperiod and had an air velocity of 0.3m.s$^{-1}$ and relative humidity of 80%. Plug seedlings raised were transplanted to rockwool slabs in a glasshouse and were grown hydroponically using the same nutrient solutions used for seedling culture for 37 days (experiment 1) and 35 days (experiment 2). Plant height was affected more by mean daily temperature than by interaction of day and night temperatures. Plant height was the highest in 16/16$^{\circ}C$ treatment. Leaf count was not affected by day and night temperatures, and the chlorophyll concentration was the highest in 16/$25^{\circ}C$ treatment. Fresh and dry weights of stem tended to be greater in treatments of constant day and night temperature. The number of node on which first and second flower clusters were set was significantly higher in 25/$25^{\circ}C$ treatment than in the other treatments. Days to flower of the first flower on the first flower cluster were the greatest in 25/$25^{\circ}C$ and the least in 16/$25^{\circ}C$ treatment. Vegetative and reproductive growth, such as height, fresh and dry weights, days to flower, and nodes of the 1st and 2nd flower cluster set were affected by day/night temperatures.

• Journal of the Korean Chemical Society
• /
• v.44 no.5
• /
• pp.422-428
• /
• 2000

Optimum analytical conditions of the aluminium ion were established by flow injection analysis. Eriochrome Cyanine R(ECR) dye reacts with the aluminium ion at pH 6.0 to form a complex that exhibits maximum absorption at 535 nm. Reaction conditions including the mixing and the reaction coil length, the concentration and the pH of the buffer solutio, temperature, and injection loop volume were optimized to intro-duce this reaction into flow injection analysis. The results were as follows. A mixing coil length of 0.5 m and a reaction coil length of 4.0 m, the pH 6.0 and 1M of acetate buffer solution, the ECR concentration of 0.56 mM, the reaction temperature of 40$^{\circ}C$, the injection loop volume of 300${\mu}L$ were chosen as optimum conditions. Under these conditions the detection limit of the aluminiumion was less than 0.05 mg/L and the repeatability was better than 1%. A sampling frequency of 24 times for an hour was achieved. Interfering ions such as $F^-$, HP$O_4^{2-}$, $Fe^{2+}$, $Fe^{3+}$, $Mn^{2+}$, and other anions were tested, interference did not occur up to 1,000mg/L of ion concentration and up to 2,CO0mg/L of sulfate ion con-centration. This method was applied for the determination of aluminium ion in tap water and ground water of Jeonju and the Gochang area. The results showed that the aluminium residual in tap water of the Jeonju area was at a mean of 0.478mg/L and that in tap water of the Gochang area was at a mean of 0.278mg/L. Aluminium ion residual of the tap waters in the Jeonju area was higher level than that in the Gochang area. Aluminium residual in the ground water of the Jeonju area was 0.386 mg/L and was lower compared to 0.564 mg/L for the Gochang area.

• Korean Journal of Environmental Agriculture
• /
• v.38 no.3
• /
• pp.166-172
• /
• 2019

BACKGROUND: Increase in the ratio of small berries in blueberry production decreases the farmers' profits due to weakening market competitiveness and lowering harvest efficiency. One of the reasons for increased small berries is over fruit-load. For improving productivity and competitiveness of blueberry in Korea, hand-thinning can be applied to increase fruit quality before the developing adequate chemical thinning methods. This study was conducted to investigate the proper timing and methods for floral buds thinning in rabbiteye blueberry. METHODS AND RESULTS: Eight years old bushes of rabbiteye bluberries 'Brightwell' as a primary cultivar and 'Powderblue' as a pollinizer were used for this study. Fruit size distribution by leaf-to-fruit ratio was investigated by counting the number of leaves and fruits in canes of 127 'Brightwell' plants whose fruit set varied. Fifty percent of flowers/floral buds were removed in four different floral buds stages such as bud swell, late pink bud, full bloom, and petal fall, and the consumed time for thinning and fruit characteristics were recorded to investigate the effect and proper timing of floral buds thinning. Fruit weight and soluble solids content tended to increase in proportion to leaf-to-fruit ratio and the production of the number of fruits less than 13 mm in diameter decreased when leaf-to-fruit ratio was more than 2.5. Manual floral buds thinning by hands was fastest in full bloom stage and slowest in bud swelling stage. In all cultivars, fruit size was significantly smaller in non-thinning treatment than thinning, and there was, however, no significant difference in total fruit yield. The number of fruits less than 13 mm in diameter increased in both cultivars as floral buds thinning was delayed. Consumed time for picking 90% berries out of total berries per bush was shortest in full bloom stage thinning in 'Brightwell' and bud swelling, full bloom thinning in 'Powderblue'. These were 25 and 20 days faster than no thinning, respectively. CONCLUSION: Although the effect of floral buds thinning varied depending on the cultivars, our results confirmed that floral buds thinning was effective for the early intensive harvesting and the increase of the large fruit ratio and the harvesting productivity. Also, in order to increase thinning efficiency, it is recommended to remove the flower buds before the full bloom stage.