• 자원리싸이클링
• /
• 제28권5호
• /
• pp.42-50
• /
• 2019

본 연구에서는 바나듐을 회수하기 위하여 수용액의 바나듐과 염화암모늄 침전반응에 관하여 고찰하였다. 바나듐 함유 수용액 pH 9.2 ~9.4에서는 결정구조가 [$NH_4VO_3$]인 암모늄메타바나데이트가 침전되었고, 바나듐 함유 수용액의 pH를 황산으로 조절하면 결정구조가 [$(NH_4)_2V_6O_{16}$]인 암모늄폴리바나데이트가 침전되었다. 암모늄폴리바나데이트[$(NH_4)_2V_6O_{16}$]는 바나듐 함유 수용액 pH 2에서는 침전온도 $80{\sim}90^{\circ}C$에서, 그리고 수용액 pH 6 ~ 8에서는 침전온도 $40^{\circ}C$에서 침전되었다. 또한 수용액 pH 2인 산성 영역에서 99% 이상의 침전률을 얻기 위해서는 수용액의 바나듐 함량이 3,000 mg/L 이상은 되어야 하며, 침전온도는 $80^{\circ}C$ 이상으로 유지해야 한다. 알칼리 영역에서 암모늄메타바나데이트를 침전시킬 때, 바나듐 함량은 10,000 mg/L 이상 그리고 침전온도는 $40^{\circ}C$로 유지해야 침전률을 높일 수 있었다. 알루미늄은 수용액의 바나듐 함량 및 pH에 상관없이 거의 침전이 일어나지 않았으나, 철 성분은 염화암모늄과 반응하여 암모늄 자로사이트 형태로 침전되며, 따라서 바나듐의 회수율을 높이기 위해서는 Fe 성분을 우선적으로 제거해야만 한다.

• 한국염색가공학회지
• /
• 제13권2호
• /
• pp.18-18
• /
• 2001

This study has examined the removal of mixed soil of protein and fat by protease. Cotton and PET fabrics were soiled by spotting of hemoglobin and triolein, respectively. The soiling order and soil concentration were changed in this procedure. The soiled fabrics were aged at 130℃ for 20 minutes. Protease was added in the alcohol ethoxylate(AE) detergent solution. The removal effciency was evaluated by analysis of protein and/or fat on the fabrics before and after washing, respectively. The detergency of PET fabrics was higher than that of cotton fabrics. The removal efficiency of hemoglobin was improved by protease from cotton and PET fabrics. Especially the removal efficiency of hemoglobin was remarkably improved from cotton fabrics. With the increase of hemoglobin and triolein (1:1) mixed soil, the removal of mixed soil was increased in proportion to mixed soil content up to a certain point. but it began to decrease above the point from cotton fabrics, while it was generally increased from PET fabrics. The detergency of total mixed soil from cotton fabrics was higher in case of soiling order with triolein after hemoglobin than in case of soiling order with triolein before hemoglobin. But the soiling order was not greatly effected in the detergency of total mixed soil from PET fabrics.

• 한국염색가공학회지
• /
• 제13권2호
• /
• pp.104-113
• /
• 2001

This study has examined the removal of mixed soil of protein and fat by protease. Cotton and PET fabrics were soiled by spotting of hemoglobin and triolein, respectively. The soiling order and soil concentration were changed in this procedure. The soiled fabrics were aged at $130^\circ{C}$ for 20 minutes. Protease was added in the alcohol ethoxylate(AE) detergent solution. The removal effciency was evaluated by analysis of protein and/or fat on the fabrics before and after washing, respectively. The detergency of PET fabrics was higher than that of cotton fabrics. The removal efficiency of hemoglobin was improved by protease from cotton and PET fabrics. Especially the removal efficiency of hemoglobin was remarkably improved from cotton fabrics. With the increase of hemoglobin and triolein (1:1) mixed soil, the removal of mixed soil was increased in proportion to mixed soil content up to a certain point. but it began to decrease above the point from cotton fabrics, while it was generally increased from PET fabrics. The detergency of total mixed soil from cotton fabrics was higher in case of soiling order with triolein after hemoglobin than in case of soiling order with triolein before hemoglobin. But the soiling order was not greatly effected in the detergency of total mixed soil from PET fabrics.

• Steel and Composite Structures
• /
• 제33권1호
• /
• pp.81-92
• /
• 2019

The present paper addresses a refined plate theoryin order to describe the response of anti-symmetric cross-ply laminated plates subjected to a uniformlydistributed nonlinear thermo-mechanical loading. In the present theory, the undetermined integral terms are used and the variables number is reduced to four instead of five or more in other higher-order theories. The boundary conditions on the top and the bottom surfaces of the plate are satisfied; hence the use of the transverse shear correction factors isavoided. The principle of virtual work is used to obtain governing equations and boundary conditions. Navier solution for simply supported plates is used to derive analytical solutions. For the validation of the present theory, numerical results for displacements and stressesare compared with those of classical, first-order, higher-order and trigonometricshear theories reported in the literature.

• Structural Engineering and Mechanics
• /
• 제72권2호
• /
• pp.203-216
• /
• 2019

Reliability analysis of composite structures considering random variation of involved parameters is quite important as composite materials revealed large statistical variations in their mechanical properties. The reliability analysis of such structures by the first order reliability method (FORM) and Monte Carlo Simulation (MCS) based approach involves repetitive evaluations of performance function. The response surface method (RSM) based metamodeling technique has emerged as an effective solution to such problems. In the application of metamodeling for uncertainty quantification and reliability analysis of composite structures; the finite element model is usually formulated by either classical laminate theory or first order shear deformation theory. But such theories show significant error in calculating the structural responses of composite structures. The present study attempted to apply the RSM based MCS for reliability analysis of composite shell structures where the surrogate model is constructed using higher order shear deformation theory (HSDT) of composite structures considering the uncertainties in the material properties, load, ply thickness and radius of curvature of the shell structure. The sensitivity of responses of the shell is also obtained by RSM and finite element method based direct approach to elucidate the advantages of RSM for response sensitivity analysis. The reliability results obtained by the proposed RSM based MCS and FORM are compared with the accurate reliability analysis results obtained by the direct MCS by considering two numerical examples.

• Journal of Ginseng Research
• /
• 제14권2호
• /
• pp.122-125
• /
• 1990

Ethylene was released from leaf and fruit but root of Panax ginseng. Root callus showed higher ethylene release (ER) than fruit ER increased with leaf senesence. Fruit during ripening showed decreasing ER in the order of green stage, early stage of reddening and fully ripened stage. between leaves from the plant with fruits in different stages of ripening showed similar trend of fruit in ER but it was about 10 times higher in leaves than in fruits. Leaves of P. quinquefolius showed about 200 times higher ER than that of P ginseng on 22 July Fruits from the plant treated with ethephon showed higher ER after 109 days. Forty-five day-old seedlings grown with various growth regulators showed a significant decrease of stem length and significant increase of ER only in Uniconazole (0.1 ppm) and H-9 (0.0, 5 ppm) solution.

• Journal of Pharmaceutical Investigation
• /
• 제23권4호
• /
• pp.225-229
• /
• 1993

The stability of omeprazole in the aqueous solutions containing arginine or sodium phosphate dibasic(SPD) was examined at 30, 40 and $50^{\circ}C$. Arginine or anhydrous SPD was added to omeprazoie solution ($200{\mu}g/\;ml$ in distilled water) to yield $100{\mu}g/\;ml$ concentration of each. Then, the solution was kept at 30, 40 or $50^{\circ}C$ for 90 hrs. Aliquots of the solution were withdrawn at specified time intervals and assayed by HPLC for intact omeprazole. The remaining percentage-time curves revealed that omeprazole was degraded rapidly as funtions of time and temperature following pseudo first-order kinetics. The rate constant in the SPD solution was much higher than in the arginine solution. In other words. the degradation half-lives of omeprazole at $30^{\circ}C$, for example, was 148 and 76 hr in arginine and SPD solutions respectively. The initial pH of the solution containing $100{\mu}g/\;ml$ of arginine or SPD was 9.7 or 8.7, respectively. Since omeprazole is more stable as the pH of its solution becomes more alkaline, the longer half-life of omeprazole in arginine solution could be explained by the more alkaline characteristics of arginine than SPD in the solution. The activation energy necessary for the degradation reaction was almost identical in both solutions, indicating similar degradation mechanisms of omeprazole in the solutions. In conclusion, omprazole was more stable in the presence of arginine than of SPD.

• 한국농공학회지
• /
• 제35권4호
• /
• pp.38-46
• /
• 1993

This study is to analyze effect of exposure environment and mode of ASR on the engineering properties of synthetic lightweight aggregate concrete, such as dynamic modulus of elasticity and ultrasonic pulse velocity. The results of this study are summarized as foflows ; 1. The expansion rate of each exposure environment in 380$^{\circ}$C and NaCI 4% solution was shown higher than in 20$^{\circ}$C and normal water. The expansion rate of each exposure mode was largely shown in order of fjill immersion, wetting/drying, half immersion. 2. The dynamic modulus of elasticty and ultrasonic pulse velocity of each exposure environment in 38$^{\circ}$C and NaCl 4% solution was shown less than in 20$^{\circ}$C and normal water. The dynamic modulus of elasticity and ultrasonic pulse velocity of each exposure mode was shown smaller in order of full immersion, wetting/drying, half imersion.3. The relation between dynamic modulus of elasticity and ultrasonic pulse velocity was highly significant. The dynamic modulus of elasticity was increased with increase of ultrasonic pulse velocity. The decreasing rate of the dynamic modulus of elasticity was shown 2.1~3.4 times higher than the ultrasonic pulse velocity at each age, exposure environment and mode, respectively. 4. The expansion of each exposure environment and mode was increased with increase of curing age. The dynamic modulus of elasticity and ultrasonic pulse velocity of those concrete was increased with increase of curing age. At the curing age 28 days, the highest properties was showed at each type concrete, it was gradually decreased with increase of curing age. Specially, at the curing age 98 days of full immersion, the rate of expansion of type D was shown 3.95 times higher than the type A. But the dynamic modulus of elasticity and ultrasonic pulse velocity was decreased 17% and 8.3%.

• Advances in environmental research
• /
• 제6권2호
• /
• pp.113-125
• /
• 2017

Santa Barbara Amorphous-15(SBA-15) nanoparticles were utilized as the inexpensive and effective adsorbents to remove methylene blue dye from the aqueous solution.SBA-15 was created by Zhao et al method. Infrared spectroscopy, X-ray diffraction and scanning electron microscopy (SEM) were used for the evaluated physical properties of SBA-15. The results of diffraction X-ray indicated that was the crystalline structure for it. Also IR spectroscopy indicated was a silica the whole structure of the groups and SEM image verify the structure of relatively identical particles size of SBA-15. Factors affecting adsorption including the amounts of adsorbent, pH and contact time were investigated by a SBA-15 nanomaterial design. The extent of dye removal enhanced with increasing initial dye concentration and pH from 4 to 10. The higher percentage adsorption were obtained under optimum conditions of variables (sorbent dose of 200 mg/liter, initial MB concentration 10 mg/liter, initial pH of 10 and temperature of $25^{\circ}C$). Maximum adsorption happened after the 2 hour and the kinetic processes of the dyes adsorption were described by applying the pseudo-first-order and the pseudo-second-order and the relatively High correlation with the kinetic Ellovich models. It was found that the pseudo-second-order models kinetic equation described the data of dye adsorption with a good correlation (R2>0.999) which indicated chemisorption mechanism. Freundlich and Langmuir adsorption models were investigated in conditions of variables (adsorbent dose 0.01 gr/liter, MB concentration 10, 20, 30 mg/liter, pH of 4, 7, 10, contact time 90 min and temperature of $27^{\circ}C$). The adsorption data were represented by Langmuir isotherm model. These values are higher than the adsorption capacities of some other adsorbents that have recently been published in the literature.

• 대한조선학회논문집
• /
• 제39권1호
• /
• pp.8-15
• /
• 2002

B-spline을 이용하여 물체의 형상과 포텐셜을 표현함으로써, 저차경계요소법의 단점들을 극복하고 수치계산의 정도를 높이기 위한 고차 패널법을 개발하였다. 물체표면과 자유표면에 법선 다이폴과 쏘스를 분포시켰으며, 자유표면 및 방사조건을 만족시키기 위해 상류차분식을 사용하는 대신 B-spline의 기저함수를 미분하여 선형화된 자유표면 경계조건에 직접 적용하였다. 이 방법을 적용함으로써 Dawson 방법에서 문제가 되었던 수치감쇠 문제를 피할 수 있었다. 수치계산 프로그램을 검증하기 위해 2차원 원주주위의 유동계산과 날개면 주위의 유동해석을 수행하였으며, B-spline 기저 고차패널법에 의한 수치계산 결과가 저차패널법에 비해 빠른 수렴성과 정확성을 보였고 계산에 필요한 패널 수가 현저히 줄어드는 대단히 만족스러운 결과를 얻었다.