• Solar Energy
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• v.11 no.2
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• pp.34-40
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• 1991

Thermal stratification enhancement for the higher extraction efficiency of hot water storage tank was experimentally studied with transparent fiber glass cylindical tank($350{\ell}$, D=516mm, H=1680mm). Height to diameter ratio (H/D =1,2,3), flow rate(Q= 8,10,12LPM), inlet-outlet temperature differences(${\Delta}T=20,25,30^{\circ}C$), and geometry of inlet-outlet port were the parameters. In particular, three kind of distributors were used for geometry of inlet-outlet port. As a result, it was possible to get extraction efficiency of 95% by using the distributor having variable diameter but keeping a constant diameter of perforation. So it is recommendable to design the distributor so that the main pipe decrease in diameter toward the dead end.

• Natural Product Sciences
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• v.27 no.1
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• pp.10-17
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• 2021

The purpose of this study is to develop a new method of producing tienchi seng (notoginseng, Panax notoginseng) extracts featuring high concentrations of the ginsenoside Rg3, Rg5, and Rg6, special components of Korean red ginseng. The chemical transformation from ginseng saponin glycosides to prosapogenin was analyzed by HPLC. Tienchi seng was heat-processed at 100℃ and the optimum conditions were identified. The highest concentrations of total saponin (29.723%) and the ginsenoside Rg3 (1.769%), Rg5 (5.979%), and Rg6 (13.473%) were produced at 48 hours. Also, when tienchi seng was subjected to the ultrasonic thermal fusion (100℃) process, the concentrations of total saponin (30.578%), ginsenoside Rg3 (2.392%), Rg5 (6.614%), and Rg6 (13.017%) were highest at 36 hours. On the other hand, the 2-hour heat-processed extract and 2-hour ultrasonic thermal fusion-processed extract did not contain ginsenoside Rg3, Rg5, and Rg6. The ultrasonic thermal fusion process had an extraction yield that was approximately 1.26 times greater than that of the heat process. These results indicate that the highly functional tienchi seng extracts created through the ultrasonic thermal fusion process are more industrially useful than those produced using the heat process.

• Fisheries and Aquatic Sciences
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• v.17 no.2
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• pp.159-165
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• 2014

In this study, Krill Eupausia superba oil was extracted using different solvents and supercritical carbon dioxide (SC-$CO_2$). During SC-$CO_2$ extraction, the pressure was set at 40 MPa and temperatures ranged from $40^{\circ}C$ to $55^{\circ}C$. We examined the differences in volatile compounds and safety profiles among extraction methods. Volatile compounds were determined using the thermal desorption system integrated with gas chromatography-mass spectrometry (GC-MS). Heavy metal content was analyzed by inductively coupled plasma mass spectrometry (ICP-MS). According to our results 10 volatile compounds were identified in krill sample. After SC-$CO_2$ extraction of oil, the concentrations of volatile compounds decreased, but increased after solvent extraction. In krill, heavy metal concentrations remained within the permissible limit. Moreover, Zn and Fe which have health benefits were detected at high concentrations. During a 90 days storage period at different temperatures, microbial activity was found to be lowest in SC-$CO_2$ extracted residues. Thus, the quality of krill oil and the residues obtained using SC-$CO_2$ extraction was higher and the oil was safer than those obtained using conventional solvent extraction. These results can be applied to the food industry to maintain high quality krill products.

• Preventive Nutrition and Food Science
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• v.17 no.2
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• pp.166-171
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• 2012

6-Shogaol, a dehydrated form of 6-gingerol, is a minor component in ginger (Zingiber officinale Roscoe) and has recently been reported to have more potent bioactivity than 6-gingerol. Based on the thermal instability of gingerols (their dehydration to corresponding shogaols at high temperature), we aimed to develop an optimal process to maximize the 6-shogaol content during ginger extraction by modulating temperature and pH. Fresh gingers were dried under various conditions: freeze-, room temperature (RT)- or convection oven-drying at 60 or $80^{\circ}C$, and extracted by 95% ethanol at RT, 60 or $80^{\circ}C$. The content of 6-shogaol was augmented by increasing both drying and extraction temperatures. The highest production of 6-shogaol was achieved at $80^{\circ}C$ extraction after drying at the same temperature and the content of 6-shogaol was about 7-fold compared to the lowest producing process by freezing and extraction at RT. Adjustment of pH (pH 1, 4, 7 and 10) for the 6-shogaol-richest extract (dried and extracted both at $80^{\circ}C$) also affected the chemical composition of ginger and the yield of 6-shogaol was maximized at the most acidic condition of pH 1. Taken together, the current study shows for the first time that a maximized production of 6-shogaol can be achieved during practical drying and extraction process of ginger by increasing both drying and extracting temperatures. Adjustment of pH to extraction solvent with strong acid also helps increase the production of 6-shogaol. Our data could be usefully employed in the fields of food processing as well as nutraceutical industry.

• KSBB Journal
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• v.23 no.5
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• pp.362-368
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• 2008

High Hydrostatic Pressure assisted (HHP) process enhancement for food and allied industries are reported in this paper review. Recently, considerable research has been devoted to the improvement of mild thermal processing techniques and to the development of alternative mild processing technologies. HHP assisted can enhance existing extraction, processes and enable new commercial extraction opportunities and processes. New HHP processing approaches have been proposed, including, the potential for modification of plant cell material to provide improved bioavailability of micro nutrients while retaining the natural-like quality, simultaneous extraction. Therefore, High Hydrostatic Pressure assisted (HHP) technologies could have a strong presence in the future of the biotechnology industry.

• Nuclear Engineering and Technology
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• v.54 no.5
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• pp.1560-1569
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• 2022

Liquid fueled molten salt reactors (MSRs) have seen renewed interest because of their inherent safety features, higher thermal efficiency and potential for efficient thorium utilisation for power generation. Thorium fluoride is one of the salts used in liquid fueled MSRs employing Th-U cycle. In the present study, ThF₄ was prepared by hydro-fluorination of ThO₂ using anhydrous HF gas. Process parameters viz. bed depth, hydrofluorination time and hydrofluorination temperature, were optimized for the preparation of ThF₄ in a static bed reactor setup. The products were characterized with X-Ray diffraction and experimental conditions for complete conversion to ThF₄ were established which also corroborated with the yield values. Hydrofluorination of ThO₂ at 450 ℃ for half an hour at a bed depth of 6 mm gave the best result, with a yield of about 99.36% ThF₄. No unconverted oxide or any other impurity was observed. Rietveld refinement was performed on the XRD data of this ThF₄, and Chi2 value of 3.54 indicated good agreement between observed and calculated profiles.

• Journal of the Korean Ceramic Society
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• v.18 no.1
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• pp.27-34
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• 1981

The phase separation of low-alkali borosilicate glass with the composition of $6.25Na_2O$.$18.75B_2O_3$.$75.00SiO_2$(mole%) substituting $Li_2O$ for $Na_2O$ was studied. The phase separation in the temperature range of transformation was examined with various heating temperatures and soaking times. Durability to water, thermal expansion and specific density of the specimen were investigated and the microstructure of the separated phase was also observed by transmission electron micrograph techniques. The maximum alkali extraction result with the best phase separation effect was obtained when $Na_2O$ of the base glass was replaced with $1.88Li_2O$ (mole %) and electron micrograph of carbon film replica of $1.88Li_2O$$4.37Na_2O$.$18.75B_2O_3$.$75.00SiO_2$ (mole %) glass showed that the glass consisted of homogeneous two phases. The minimum specific density was shown with the specimen treated at 57$0^{\circ}C$ and it was also shown that the longer the treating time the lower the specific density. The apparent activation energies of approximately 45 kcal/mole by the alkali extraction and 43kcal/mole by the thermal expansion method were derived from the Arrhenius plots, respectively.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.12
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• pp.2655-2661
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• 2009

In this paper, an accurate noise parameters for thermal noise modeling of short channel MOSFET is derived and extracted. Fukui model for calculating the noise parameters of a MOSFET is modified by considering effects of parasitic elements in short channel, and it is compared with conventional noise model equation. In addition, for obtaining the intrinsic noise sources of devices, noise parameters(minimum noise figure $F_{min}$, equivalent noise resistance $R_n$ optimized source admittance $Y_{opt}=G_{opt}+B_{opt}$) in submicron MOSFETs is extracted. With this extraction method, the intrinsic noise parameters of MOSFET without effects of probe pad and extrinsic parasitic elements from RF noise measurements can be directly obtained.

• KSBB Journal
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• v.13 no.5
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• pp.599-605
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• 1998

Soybean peroxidase was extracted from soybean hulls and purified by ammonium sulfate precipitations (25% and 75% saturation), pl fractionation, and anionic exchange and gel filtration chromatographies (DEAE-Sephadex A-50 and Superose 12). Modlecular weight and pl value were estimated to be ca. 45 kD and 4.2, respectively. Purified soybean peroxidase had an RZ value of 0.43. Compared with horseradish peroxidase, it showed superior thermal and pH stability. Assuming the first-order kinetics, the thermal deactivation rate constant of soybean peroxidase at 80$^{\circ}C$ was about 8 times lower than that of horseradish peroxidase. Deactivation energy was calculated to be 69.3 kcal/mol. Soybean peroxidase showed about 10% higher H2O2 degradation capacity than horseradish peroxidase. Exploiting these advantages, the soybean peroxidase purified from the domestic soybean hull is expected to replace horseradish peroxidase in various applications.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.25 no.4
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• pp.451-460
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• 2001

An analysis program for the thermal performance prediction of steam turbine cogeneration systems with multi-extraction, reheat and regeneration has been developed on the basis of the thermodynamic heat balance method. Heat balance analyses were performed for a commercial cogeneration power plant using the program. Its appropriateness was verified by comparing its heat balance results with those of other commercial programs and those provided by the original system designer. Further parametric analyses were carried out and performance improvement measures in designing the plant were suggested.