• Journal of the Korean Ceramic Society
• /
• v.30 no.6
• /
• pp.478-484
• /
• 1993

The influence of reaction conditions on the MnZn ferrite coprecipitation process were investigated using mixed metla sulfate solution and ammonium oxalate. In order to minimize the metallic ion losses and to control the particle size, the optimum reaction conditions were as follows; reaction temperature $25^{\circ}C$, metal sulfate concentration 0.3M, molar ratio of ammonium oxalate/mixed metal sulfate 1.1:1. The production yield was as high as 97.6% of theoretical yield at optimum reaction condition.

• 한국생물공학회:학술대회논문집
• /
• 2000.11a
• /
• pp.587-589
• /
• 2000

The production of inulooligosaccharides from inulin by a dual endoinulinase system of Pseudomonas sp and Xanthomonas sp. was investigated the optimum conditions for a dual endoinulinase reaction were as follows : pH,5.8; temperature, $50^{\circ}C$; substrate concentration, 50 g/l; enzyme ratio, 3:1 as Xanthomonas endoinulinase to Pseudomonas endoinulinase. Under optimum conditions, the maximum yield of oligosaccharides was 90.5% in total sugar basis by dual endoinulinase system

• The Korean Journal of Food And Nutrition
• /
• v.6 no.4
• /
• pp.307-313
• /
• 1993

Bacillus cereus $\beta$-amylase was purified by Sephadex G-100 gel filtration, CM Sephadex C-50 ion exchange chromatography and CM Sephadex C-50 ion exchange rechromatography The purified enzyme showed 871 unit/mg of specific activity. The purified enzyme was identified as homogenious by disc PAGE, SDS-PAGE and analysis of reaction product. The purified enzyme showed optimum pH 7.0. optimum temperature 5$0^{\circ}C$, and was stable at 0~5$0^{\circ}C$ and at pH range of 6~10.

• Bulletin of the Korean Chemical Society
• /
• v.30 no.9
• /
• pp.2011-2016
• /
• 2009

To resolve the differentiation problem of acetone and acrolein in the analysis of carbonyls by high-performance liquid chromatography (HPLC), we investigated the optimum analytical conditions for their separation. Carbonyl compounds were collected by 2,4-dinitrophenylhydrazine (DNPH)-coated cartridges. We examined the influence of three experimental variables: temperature (25, 30, 40, 50 and 60 ${^{\circ}C}$), flow rate (1.0 and 1.2 mL/min), and relative mobile phase composition (among acetonitrile, water and tetrahydrofuran). The experimental results revealed the optimum analytical condition of a flow rate of 1.2 mL/min, temperature of 32 ${^{\circ}C}$ and mobile phase composition of acetonitrile: water: tetrahydrofuran = 34 : 52.8 : 13.2. The analysis of indoor air composition indicated that acrolein and acetone comprised 11% and 42% of all aldehydes, respectively.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.28 no.10
• /
• pp.1458-1466
• /
• 2004

Deterministic optimum designs that are obtained without consideration of uncertainties could lead to unrealiable designs. Such deterministic engineering optimization tends to promote the structural system with less reliability redundancy than obtained with conventional design procedures using the factor of safety. Consequently, deterministic optimized structures will usually have higher failure probabilities than unoptimized structures. This paper proposes the reliability based design optimization technique fur apressure tank considering temperature effect. This paper presents an efficient and stable reliability based design optimization method by using the advanced first order second moment method, which evaluates a probabilistic constraint for more accuracy. In addition, the response surface method is utilized to approximate the performance functions describing the system characteristics in the reliability based design optimization procedure.

• Food Science and Preservation
• /
• v.2 no.2
• /
• pp.285-291
• /
• 1995

This study was performed to investigate the optimum moisture content and the best packaging method of dried persimmons for long term storage at room temperature. The package material to be used were 0.05mm polyethylene film, Wrap film, 0.08mm LDPE film exchanged nitrogen gas, and non package for untreated control. Before the storage, the initial moisture contents of dried persimmons were treated with 40%, 35% and 30%, respectively; 40% as traditional dryness, 35% as extending dry period one more week, and 30% as for two more weeks. The best package method was 0.08mm LDPE film exchanged nitrogen gas, and the optimum moisture control was 35%

• International Journal of Concrete Structures and Materials
• /
• v.18 no.2E
• /
• pp.103-109
• /
• 2006

Spalling is defined as damages to concrete exposed to high temperature during fire, causing cracks and localized bursting of small pieces of concrete. As the concrete strength increases, the degree of damage caused by spalling becomes more serious due to impaired permeability. It is reported that polypropylene(PP) fiber has an important role in protecting concrete from spalling, and the optimum dosage of PP fiber is 0.2%. However, this study was conducted on non-reinforced concrete specimens. The high-temperature behavior of high-strength reinforced concrete columns with various concrete strength and various quantity of PP fibers is investigated in this study. The results revealed that the ratio of unstressed residual strength of columns increased as the concrete strength increased and as the quantity of PP fiber increased from 0% to 0.2%. However, the effect of PP fiber quantity on residual strength of column was barely above 0.2%.

• Proceedings of the Korean Society for Food Science of Animal Resources Conference
• /
• 1997.06a
• /
• pp.19-39
• /
• 1997

Extrusion conditions were optimized for blends of ground lamb and starch using a single-screw extruder for the purpose of producing expanded snack-type products. A central composite rotatable response surface methodology(RSM) design was used with variation in feed moisture, process temperature, and screw speed. The three variables significantly affected one or more of the measured physical properties of extrudates. The optimum conditions for minimum shear force values were 26.5% feed moisture, $148^{\circ}C$ process temperature, and 134 rpm screw speed. Lean ground beef, chicken, goat, lamb or mutton was blended with corn starch, and extruded at the optimum condition established from RSM experiments. Physical/rheological properties were generally similar, water activity was low (<0.12) and total aerobic plate counts were <10 for all products. Extrudates containing chicken had the highest ratio of polyunsaturated fatty acids to saturated fatty acids, whereas those containing beef had the highest ratio of monounsaturated fatty acids to saturated fatty acids. Sensory data indicated that texture was acceptable and flavor characteristics were not different among the products.

• Journal of the Korean Society for Precision Engineering
• /
• v.21 no.1
• /
• pp.80-86
• /
• 2004

With the increasing demand of environmentally clean machining in recent years, the use of coolants has been restricted extensively. In this paper, a multiple comparison method(Tukey's HSD method) is proposed to choose the optimum level of coolant necessary for an efficient and environmentally clean machining. The cutting temperature, specific cutting energy, and surface roughness in turning process are analysed by ANOVA(Analysis Of Variance) and Tukey's HSD method. From the experimental results and statistical analysis, it is found that the optimum condition of coolant level is 10 ml/min with 6% mix ratio, which is almost half of the commonly used level.

• Proceedings of the KAIS Fall Conference
• /
• 2009.12a
• /
• pp.100-102
• /
• 2009

Effect of temperature, pH and soil depth on germination of Dianthus chinensis, Dianthus barbatus, and Perennial pennant were investigated in growth chamber and soil condition at the ratio of 7:3 (natural soil and organic soil) in laboratory condition. the optimum temperature for seed germination was recorded for $20^{\circ}C-\;25^{\circ}C$. Maximum germination was observed for Dianthus barbatus (76%) where as in soil condition Perennial pennant (51%) showed maximum germination at 1 cm soil depth. Similarly, optimum pH for seed germination was at pH 6 in all the species. So in lower pH (at pH4) seed germination was inhibited. Germination of these selected species at different environmental condition help to construct the ecological sound proof wall to mitigate the noise especially in urban areas.