• Journal of Applied Biological Chemistry
• /
• v.61 no.3
• /
• pp.239-243
• /
• 2018

Essential oils of coriander (Coriandrum sativum L.) seeds were extracted by three extraction methods, steam distillation extraction (SDE), hexane extraction (HE) and supercritical extraction (SE), to compare their insecticidal activities against Sitophilus oryzae and S. zeamais. Although the essential oil extracted by HE and SE did not show insecticidal activities, the essential oil extracted by SDE showed the highest insecticidal activities against S. oryzae and S. zeamais. The chemical compositions of the essential oil extracted by SDE were analyzed by GC-MS. The most abundant compounds were linalool (59.92%), camphor (7.94%), linalool oxide (7.70%), p-cymene (7.44%), ${\alpha}-pinene$ (6.44%), limonene (3.29%) and geranyl acetate (3.19%). Camphor and linalool as major constituents showed the highest insecticidal activities against S. oryzae and S. zeamais whereas other constituents did not show insecticidal activities. As a result, the essential oil extracted by SDE, camphor and linalool showed a potential for development as insecticide against the storage pests.

• Microbiology and Biotechnology Letters
• /
• v.45 no.1
• /
• pp.1-11
• /
• 2017

In this review, we focus on one of the most attractive biomaterials, microfibrillated cellulose (MFC). MFC, a type of nanocellulose, mainly originates from cellulose in lignocellulosic biomass. MFC represents one of incredible important natural resources due to its abundancy, renewability, and sustainability. MFC is produced through mechanical pretreatment, and it is composed of various sizes of microfibers, ranging from a few nanometers to a few micrometers. Because of the heterogenetic compositions of MFC, it possesses superior properties as a material, such as high surface area, high aspect ratio, and peculiar insolubility as a biomaterial. These properties allow MFC to be used in various bio-industries, from the traditional pulp industry to the high-tech food/bio/chemical/medical industries. However, it is difficult to use MFC on a commercial scale owing to the high energy input required during its production and the challenge of controlling its reactivity. Therefore, future studies should be focused on accurately characterizing MFC's surface morphologies, regulating its characteristics in a desirable direction, and standardizing proper guidelines for the analysis of surface morphologies its analysis.

• Environmental Engineering Research
• /
• v.24 no.4
• /
• pp.699-710
• /
• 2019

Electric vehicles (EVs) are spreading rapidly and many counties are promoting hybrid and fully EVs through legislation. Therefore, an increasing amount of lithium ion batteries will reach the end of their usable life and will require effective and sustainable end-of-life management plan which include landfill disposal or incineration. The current research focuses on more sustainable methods such as remanufacturing, reuse and recycling in order to prepare for future battery compositions and provide insights to the need recycling methods to be developed to handle large amounts of batteries sustainably in the near future. The two most prominent material recovery techniques are hydrometallurgy and pyrometallurgy which are explored and assessed on their relative effectiveness, sustainability, and feasibility. Hydrometallurgy is a superior recycling method due to high material recovery and purity, very low emissions, high prevalence of chemical reuse and implementation of environmentally sustainable compounds. Expanding recycling technologies globally should take the research and technologies pioneered by Umicore to establish a sustainable recycling program for end-of-life EVs batteries. Emerging battery technology of Telsa show the most effective designs for high performance batteries includes the use of silicon which is expected to increase capacity of batteries in the future.

• Environmental Engineering Research
• /
• v.25 no.3
• /
• pp.335-344
• /
• 2020

This work describes highly efficient recovery and selective leaching of Zn from electric arc furnace dust (EAFD) with different physicochemical properties, induced by acid leaching at ambient conditions. The chemical compositions, mineralogical phases, and particle sizes of the EAFDs were analyzed and compared. The effects of leaching time, liquid/solid ratio, acid type, and acid concentration on the selective leaching of Zn were also studied. The EAFD with high Fe/Zn ratio (> 1, EAFD₃) was richer in ZnFe₂O₄ and exhibited larger particle size than samples with low Fe/Zn ratio (< 1, EAFD_1,2). ANOVA analysis revealed that the Fe/Zn ratios of the EAFDs also have a significant effect on Zn extraction (p < 0.005). Selective leaching of Zn with minimum Fe dissolution was obtained at pH > 4.5, regardless of other parameters or sample properties. The maximum Zn extraction rate obtained by the pH control was over 97% for EAFD₁ and EAFD₂, 76% for EAFD₃, and 80% for EAFD₄. The present results confirm that the Fe/Zn ratio can be used to identify EAFDs that permits facile and high-yield Zn recovery, and pH can be used as a process control factor for selective leaching of Zn regardless of any differences in the properties of the EAFD sample.

• Journal of the Korean Applied Science and Technology
• /
• v.33 no.1
• /
• pp.168-175
• /
• 2016

The surface of glass fiber bundle was modified with functionalized silanes and phenolic resin to improve the tensile strength as well as the adhesion of glass fiber to matrix phenolic resin. The surface modification of reinforcing glass fiber can play a significant role in controlling whole composite characteristics. We applied surface modification of glass fiber with two different functionalized silanes, such as glycidyltrimethoxysilane(G-silane) and aminopropyltriethoxysilane (A-silane), and phenol formaldehyde(PF) resin in one pot or separated process under different coating compositions and temperatures. Thermal treatment temperature is very important factor to improve the mechanical properties of modified glass fiber. Modified glass fiber bundle treated at $170^{\circ}C$ showed the highest tensile strength of $10.05g_f/D$. Surface analyses by scanning electron microscope(SEM) and FT-IR spectroscopy were used to characterize the surface coatings on glass fiber bundles. Mechanical property changes as functions of treatment conditions and coupling agent types were also explained.

• Fisheries and Aquatic Sciences
• /
• v.17 no.1
• /
• pp.85-93
• /
• 2014

A 9-week feeding experiment was designed to test the effects of the dietary inclusion of distillers dried grain (DDG) on the growth performance, body composition, and antioxidant activity of juvenile rockfish Sebastes schlegeli. Five isonitrogenous and isocaloric diets were formulated to contain 0% DDG (DDG0), 7% and 14% DDG from rice (diets DDG-R7 and DDG-R14, respectively), as well as 7% and 14% DDG from rice and wheat flour (diets DDG-RW7 and DDG-RW14, respectively). Three replicate groups of juvenile rockfish averaging $68.0{\pm}0.4g$ were fed one of the diets to apparent satiation twice a day. Survival, weight gain, feed efficiency, and the protein efficiency ratio of fish were not affected by dietary DDG (P > 0.05). Proximate and amino acid compositions of the whole body were not affected by dietary DDG (P > 0.05). Plasma total protein, glucose, total cholesterol, glutamate oxaloacetate transaminase, glutamate pyruvate transaminase, phospholipid, and triglyceride were not affected by dietary DDG (P > 0.05). Radical scavenging activity on 1,1-diphenyl-2-picryl-hydrazyl (DPPH) in the plasma of rockfish fed the DDG-RW14 diet was higher than that of fish fed the DDG0 diet (P < 0.05). Hydroxyl radical scavenging activity in the liver of rockfish fed diets containing DDG was higher than that of fish fed the DDG0 diet (P < 0.05). Alkyl radical scavenging activity in the liver of rockfish fed the DDG-R7 diet was higher than that of fish fed the DDG0 diet (P < 0.05). These results suggest that DDG is a suitable ingredient for the partial replacement of wheat flour and can be used at a rate of up to 14% in the diet without incurring negative effects on the growth performance or body chemical composition of juvenile rockfish.

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
• /
• 2003.10a
• /
• pp.226.2-227
• /
• 2003

The degree of milling is an important factor in terms of the nutritional value and the economic return of the milled rice. This study was to investigate the changes in compositions of the oils obtained from rice with different degree of milling. The content of total tocols in rice significantly (p＜0.05) decreased, as degree of milling increased. The relative ％ of -tocopherol in brown rice had lower than those in milled rices whereas the relative ％ of -tocotrienol, and -tocotrienol in brown rice higher than those in milled rices. -Oryzanol content significantly (P<0.05) decreased from 198.5 mg/kg rice for brown rice (0% milling) to 65.5 125.0 mg/kg rice for rice samples with 5.6, 8.0, and 9.6 ％ milling. -Sitosterol was most abundant sterol representing 50 ％ - 56% of the total sterol content in all analyzed samples. The content of total sterol as well as each sterol isomers in rice significantly (P<0.05) decreased, as degree of milling increased. A similar trend was observed in changes of octacosanol and squalene.

• Journal of Korea Foundry Society
• /
• v.33 no.4
• /
• pp.162-170
• /
• 2013

The effects of Mn content and cooling rate on the eutectic reaction of flake graphite cast irons were studied by a combined analysis of macro/micro-structure and cooling curve data. The correlation between the eutectic reaction parameter and macro/microstructure was systematically investigated. Two sets of chemical compositions with different Mn contents were designed to cast. Three types of molds for cylindrical specimens with different diameters were prepared to analyze the cooling rate effect. The difference between undercooling temperature and cementite eutectic temperature (${\Delta}T_1=T_U-T_{E,C}$), which is decreased by increasing the Mn content or increasing the cooling rate, is considered to be a suitable eutectic reaction parameter for predicting graphite morphology. According to the criterion, A-type graphite is mainly suggested to form for ${\Delta}T_1$ over $20^{\circ}C$, and D-type graphite is mainly suggested to form for ${\Delta}T_1$ below $0^{\circ}C$. Eutectic reaction time (${\Delta}T$), which is increased by increasing the Mn content and decreased by increasing the cooling rate, is regarded as a suitable eutectic reaction parameter for predicting eutectic cell size. Eutectic cell size is found to decrease in proportion to the decrease of ${\Delta}T$.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.28 no.3
• /
• pp.112-117
• /
• 2018

The metal alkoxide, CuCo-glycerate nanospheres (NSs), were successfully synthesized as Cu-Co bimetallic sulfides hierarchical multi-shelled hollow nanospheres ($CuCo_2S_4$ HMHNSs) through solvothermal synthesis. In this reaction mechanism, the solvothermal temperature and the amount of glycerol as a cosurfactant play significant role to optimize the morphology of CuCo-glycerate NSs. Furthermore, $CuCo_2S_4$ HMHNSs were obtained under optimized sulfurization reaction time of 10 h via anion exchange reaction between glycerate and sulfur ions. Finally, the structural and chemical compositions of CuCo-glycerate NSs and $CuCo_2S_4$ HMHNSs were confirmed through field emission scanning electron microscopy (FESEM), transmission electron microscope (TEM), X-ray diffraction (XRD) and electrochemical performances.

• Journal of Technologic Dentistry
• /
• v.21 no.1
• /
• pp.5-14
• /
• 1999

Glass ceramics for dental crown prosthesis were prepared by crystallization of CaO-MgO-SiO2-$P_2O_5-TiO_2$ glasses. Their crystallization behaviors have been investigated as a function of heattreatment temperature, holding time and chemical composition in relation to mechinical properties. Crystallization peak temperatures were determined by differential thermal analysis(DTA). Crystalline phases and mircostructures of heat-treated sample were determined by the means of powder X-ray diffraction(XRD) and scanning electron microscopy(SEM). The final crystalline phase assemblages and the microstructures of the samples were found to be dependent on glass compositions, heattreatment temperature, and holding time. 1st crystallization peak temperature(TP), affected strongly by apatite, was found to be increased or decreased. From the experiment, the following results were obtained : 1. The crystallization peak temperature($T_P$) formed by apatite increased until adding up to 9wt% $TiO_2$ to base glass composition, then decreased above that. 2. Apatite($Ca_{10}P_6O_{25}$), whitlockite(${\beta}-3CaO-P_2O_5$), $\beta$-wollastonite($CaSiO_3$), magnesium tianate($MaTiO_3$) and diopside(CaO-MgO-$2SiO_2$) crystal phase were precipitated in MgO-CaO-$SiO_2-TiO_2-P_2O_5$ glass system containing 9wt% and 11wt% of $TiO_2$ 3. Vickers hardness of samples increased with increasing heat-treatment temperature and Vickers hardness of S415T9 samples heat-treated at 1075 was approxi-mately 813Kg $mm^{-2}$ as maximum value. 4. Vickers hardness of samples increased due to precipitation of apatite, whitlockite, $\beta$-wollastonite, magnesium titanate, and diopside crystal phases within glass matrix.