This study aims to measure sedimentation status change with the changes in internal pressure for dry chemical extinguishers of various use periods and analyze the suitability of the fire extinguishers' performance criteria. When the internal pressure of the fire extinguisher is 0%, 2 out of 10 new dry chemical powders for the 5 elapsed years were noted to be suitable, including 3 recycled dry chemical powders with 5 elapsed years that were found eligible. One out of 10 new dry chemical powders for 10 elapsed years was shown as suitable. Also, one new dry chemical powder for 13 elapsed years was suitable. When the internal pressure of the fire extinguisher was 50%, all 10 out of 10 new dry chemical powders for 5 years, recycled one with 5 elapsed years, and a new one with 10 elapsed years were found to be suitable, while 9 new dry chemical powders for 13 years were shown as suitable. When the internal pressure of the fire extinguisher was normal, new ones with 5 elapsed years, recycled ones with 5 elapsed years, new ones with 10 elapsed years, and new ones with 13 elapsed years were all 10 out of 10 samples noted as suitable. In summarizing the experiment results, it was found that the sedimentation status, one of the fire extinguisher's physical properties experiments, affects the fire extinguisher's performance criteria rather than the change with use periods.

Looking at the dietary patterns of women in their 20s and 30s as well as postmenopausal women, the intake of most nutrients was lower than the recommended levels. Shrimp is a low-calorie, high-protein food, and contains abundant minerals, and it is expected to help prevent osteoporosis. In this study, jinmal dasik was prepared by varying the shrimp content at 0, 1, 5, and 7%, and the quality characteristics were measured. Hardness, adhesion, chewiness, and cohesiveness of physical properties increased significantly as the amount added increased (p<0.001). The springiness decreased significantly as the amount of addition increased in the addition group (p<0.001). In the calcium, there was a significant increase as the amount added increased (p<0.001). In the potassium, there was a significant increase as the amount added increased (p=0.049). This study intends to highlight the benefits and possible uses of shrimp.

This study investigated the quality characteristics and antioxidant effects of rice cookies containing different percentage of freeze-dried plum powder (3%, 5%, 6%, and 12%). The density of the dough and the thickness of the rice cookies from the control group and the additive group were not significantly different. The pH value of the dough, its moisture content and spread factor, as well as the Hunter’s L and b values of the rice cookies significantly decreased as the amount of dried plum powder added increased. However, the sweetness, hardness, thickness, Hunter’s a value, total polyphenol, total flavonoid and anthocyanin contents, DPPH and ABTS free radials scavenging activity, and ferric reducing antioxidant power of the rice cookies significantly increased as the amount of dried plum powder added increased. Overall, the results of this study showed that adding dried plum power enhanced the antioxidant activities and quality characteristics of rice cookies.

The purpose of this study was to investigate the antioxidant activities, quality characteristics, and storage stability of perilla oil mayonnaise (PM) with different levels of onion powder (OP) from 0 to 3%. As the amount of OP increased, the L, a, and b values increased, but pH decreased (p<0.05). The addition of OP raised viscosity (p<0.05). The addition of OP to PM proportionally increased the total phenolic content, and antioxidant activities as measured by DPPH and ABTS radical scavenging activity, and FRAP assay. When compared to PM without OP, PM that contained OP had a peroxide value that was almost 1.94 times lower. The emulsion stability was between 97.62 to 94.92% in the PM without OP and PM with OP groups was 99.60% for 12 weeks. This study showed that the inclusion of OP in PM has the potential to inprove its quality, antioxidant activities, and storage stability.

This study collected powder extinguishers with 6-10 years of elapsed life from January 2012 to January 2017 in market, factory, and apartment areas to experiment with changes in fineness and to examine the characteristics of extinguishing power. First, in the case of ABC powder, 98.3 wt% of the 8-year market area and 98.6 wt% of the 10-year apartment complex were found to be inappropriate in the first, second, and third arithmetic average analysis of the powder extinguisher from 6 to 10 years. That is, the fine distribution and size of the powder extinguishing agent particles should be managed within an appropriate range. It is analyzed that the powder fire extinguisher may experience a change in the fineness of the powder depending on the external environment exposure, placement, management status, and age of use, resulting in a decrease in digestive power or inability to radiate. Second, the fire extinguisher cannot be used in the initial fire suppression depending on the place of deployment, the environment of deployment, the progress of the number of years of use, and maintenance, so it is necessary to strengthen the device that enables fire extinguisher maintenance and inspection. Third, in the manufacturing process, the charging method should also be reviewed in consideration of the conditions of the workplace, the humid season, and the rainy environment.

본 연구에서는 실버 파우더의 입자 크기, 즉 평균 입자 크기가 2㎛과 7㎛, 이렇게 2가지 실버 페이스트를 개발하였다. 이렇게 개 발된 실버 페이스트에 대해서 점도 및 점탄성, 경화후에 잔류용제 유무 확인을 위한 TGA측정, Strain에 따른 저항 변화 및 전극 표면 구조 변화에 대해서 검토하였다. 이러한 결과를 정리하면 Strain에 따른 저항 변화를 최소화하기 위해서는 실버 파우더의 입 자를 2㎛정도인 것이 가장 바람직함을 알 수 있었다.

This study was conducted to investigate the effect of manufacturing temperature on curcuminoid contents and the antioxidant activity of turmeric (Curcuma aromatica Salab.) powder-enhanced nurungji. Two different processes employed turmeric powder (2%): AR (added after rice cooked) and BR (added before rice cooked). AR and BR nurungji samples were prepared by heating cooked rice at 180oC, 200oC, and 220oC for 3 minutes. As a result of the HPLC analysis, the contents of curcumin, demethoxycurcumin, and bisdemethoxycurcumin decreased as the heating temperature increased. Moreover, AR samples showed higher curcuminoids than BR samples. The total polyphenol contents, DPPH, and ABTS radical scavenging ability proportionally increased with the increase of the manufacturing temperature. On the other hand, flavonoid contents were decreased with increasing temperature. These results suggest that the preparation of turmeric powder-enhanced nurungji by AR process at 200oC is preferable to preserving curcuminoid contents and antioxidative activity.

In this study, the quality characteristics of kimchi, such as its salinity, pH, and acidity, were measured and compared, and the HT-29 human colon cancer cells were used to show the anticancer effects of kimchi. The kimchi samples used herein included standard kimchi (SK), turnip kimchi (TK), and turnip-powder-added kimchi (TPK). The measured pH and acidity of TK and TPK showed no significant differences with those of SK. Compared to SK and TK, TPK had higher DPPH scavenging activity and higher total flavonoid content, confirming its antioxidant activity. The cancer cell growth inhibition rates of TK and TPK were significantly higher than that of SK. In HT-29 cells treated with TPK, the mRNA expression of Bcl-xL, an anti-apoptosis-related gene, was lower, and the mRNA expressions of the apoptosis-related genes Bax, Bad, and caspase-9 were higher. TPK showed significantly higher levels of mRNA expressions for the cell-cycle-related genes p53 and p21 than the other samples, in addition to suppression effects on cancer cell proliferation. Compared to SK, TK and TPK suppressed the growth of colon cancer cells and showed higher anticancer effects. Therefore, it is shown that kimchi with added turnip powder had high anticancer effects.

Recently, considerable attention has been given to nickel-based superalloys used in additive manufacturing. However, additive manufacturing is limited by a slow build rate in obtaining optimal densities. In this study, optimal volumetric energy density (VED) was calculated using optimal process parameters of IN718 provided by additive manufacturing of laser powder-bed fusion. The laser power and scan speed were controlled using the same ratio to maintain the optimal VED and achieve a fast build rate. Cube samples were manufactured using seven process parameters, including an optimal process parameter. Analysis was conducted based on changes in density and melt-pool morphology. At a low laser power and scan speed, the energy applied to the powder bed was proportional to and not . At a high laser power and scan speed, a curved track was formed due to Plateau-Rayleigh instability. However, a wide melt-pool shape and continuous track were formed, which did not significantly affect the density. We were able to verify the validity of the VED formula and succeeded in achieving a 75% higher build rate than that of the optimal parameter, with a slight decrease in density and hardness.

A typical trade-off relationship exists between strength and elongation in face-centered cubic metals. Studies have recently been conducted to enhance strength without ductility reduction through surface-treatment-based ultrasonic nanocrystalline surface modification (UNSM), which creates a gradient microstructure in which grains become smaller from the inside to the surface. The transformation-induced plasticity effect in Fe-Mn alloys results in excellent strength and ductility due to their high work-hardening rate. This rate is achieved through strain-induced martensitic transformation when an alloy is plastically deformed. In this study, Fe-6%Mn powders with different sizes were prepared by high-energy ball milling and sintered through spark plasma sintering to produce Fe-6%Mn samples. A gradient microstructure was obtained by stacking the different-sized powders to achieve similar effects as those derived from UNSM. A compressive test was performed to investigate the mechanical properties, including the yielding behavior. The deformed microstructure was observed through electron backscatter diffraction to determine the effects of gradient plastic deformation.

AlSi10Mg alloys are being actively studied through additive manufacturing for application in the automobile and aerospace industries because of their excellent mechanical properties. To obtain a consistently high quality product through additive manufacturing, studying the flowability and spreadability of the metal powder is necessary. AlSi10Mg powder easily forms an oxide film on the powder surface and has hydrophilic properties, making it vulnerable to moisture. Therefore, in this study, AlSi10Mg powder was hydrophobically modified through silane surface treatment to improve the flowability and spreadability by reducing the effects of moisture. The improved flowability according to the number of silane surface treatments was confirmed using a Carney flowmeter. In addition, to confirm the effects of improved spreadability, the powder prior to surface treatment and that subjected to surface treatment four times were measured and compared using s self-designed recoating tester. The results of this study confirmed the improved flowability and spreadability based on the modified metal powder from hydrophilic to hydrophobic for obtaining a highquality additive manufacturing product.

Levels of beauvericin (BEA) and enniatins (ENNs: ENA, ENA1, ENB, and ENB1) were examined in fresh ginger (n = 43) and ginger powder (n = 31) samples from Korea. In the ginger samples, incidence of BEA contamination was highest, at 62.79%, with a maximum detected BEA level of 640.07 μg/kg. ENNs in were found in up to 11.63% (ENB, ENB1) of ginger samples, with a maximum detected level of 91.02 μg/kg (ENA). In the ginger powders, ENB contamination displayed the highest rate of incidence (70.97%), but the highest level of BEA (1,344.18 μg/kg) exceeded that of ENB (413.99 μg/kg). The incidences of ENA, ENA1, ENB, and ENB1 presence in ginger powders were 29.03%, 22.58%, 70.97%, and 35.48%, respectively, and their highest detected levels were 220.45, 156.61, 413.99, and 70.29 μg/kg, respectively. The incidence of BEA and ENN contamination was higher in ginger powder than in ginger. Respective co-occurrence rates of BEA and ENNs in ginger and ginger powder samples were 16.28% and 64.52%, indicating that the BEA and ENN co-contamination rate was highest in ginger powder as well. This is the first report on the presence and co-occurrence of BEA and ENNs in Korean ginger and ginger powder.

In nuclear power plant, there were many contaminated tanks dispose of radioactive fluid waste. These tanks are made of stainless-steel, and corrosion can occur when tanks are exposed to radioactive fluid waste containing moisture for a long time. Therefore, those sludge waste including radionuclide should be collected, solidified, and disposed of. If sludge can be melted, sludge can be easily solidified. However, melting points of sludge components (Fe2O3, NiO, Cr2O3) are very high as 1565, 1955, and 2435 , respectively. Therefore, melting sludge is difficult. If a solidification auxiliary material such as cement or asphalt is used to help solidify, solidification can easily occur, but cement and asphalt are vulnerable to heat. Vitrification using glass material can be solidification method, but the waste loading ratio of glass material is higher than 50%. High waste loading ratio is weakness in terms of volume reduction of waste. In this study, ferro frit powder (Na2O, K2O, CaO, Al2O3, B2O3, SiO2, ZnO) is used as solidification auxiliary material. When ferro frit powder mixed with sludge material are melted in sludge material, melted ferro frit powder can stick sludge material and can solidify sludge material without melting. Sludge can be solidified by using ferro frit powder with a smaller waste loading ratio than the vitrification method. However, since the waste loading ratio of the solidification auxiliary material is small, if ferro frit powder is not uniformly distributed between sludge powder, solidification may not be performed properly. Although the mixing ratio between sludge and ferro frit in solidified sludge is same, when the distribution of ferro frit powder in sludge is non-homogeneous, the difference in chemical and physical characteristics as compressive strength and leaching resistance can be observed in solidified sludge. As the ferro frit mixing ratio in the site where ferro frit exists was relatively high, the melting point of the mixed powder (sludge+ferro frit) decreased, and the mixed powder could not maintain its shape and melted. In the case of the area where ferro frit does not exist, since only the stainless-steel oxide sludge exists, sludge was not melted, and the shape was maintained. However, it was confirmed that the leaching resistance was lowered by visually observing the color change of the leachate within a short period of time (about 2 hours) when solidified sludge was immersed in the leachate.

The damaged spent fuel rods must be stabilized by encapsulation or dry re-fabrication technologies before geological disposal. For applying the dry re-fabrication technology, we manufactured a vertical type furnace to perform both fuel material recovery from damaged fuel rods by oxidative decladding and sinterability improvement of fuel powder by repetition of oxidative and reaction treatment. A horizontal type furnace provides only a diffusion-controlled reaction resulting in longer reaction time and decreasing amount of powder for oxidation and reduction, whereas a vertical type furnace with a submerged gas distributor gives rapid reaction due to flowing gas-solid contact by fluidization. For observation of fluidization behaviors of uranium oxides at room temperature, fluidized column was prepared with transparent cylindrical tube, pressure transmitter and gas flow meter. Number of size of orifice holes was determined by equations in Fluidization Engineering [D.Kunii, O. Levenspiel]. Before uranium oxide test, as surrogates, WO2 (10.8 g/cm3) and Ta2O5 (8.2 g/cm3) powder similar to density of UO2 (10.96 g/cm3) and U3O8 (8.3 g/cm3), respectively were used to achieve fluidization operation conditions in the region from minimum to expanded fluidization. Fluidization behaviors and pressure drop of powder bed was observed according to operation parameters such as gas velocity, number and size of orifice holes, and powder amount.

Coffee is the most popular beverage in the world and various pollutants, including volatile organic compounds (VOCs), are emitted from the coffee manufacturing workplace (roasting process). In this study, we analyzed the characteristics of VOCs emissions from roasted Arabica coffee bean powder using a VOCs emission chamber with a PTR-ToF-MS. The emission test was maintained under constant temperature (20 ± 2oC) and humidity (50 ± 5%) conditions. As a result of the emission test, most of the target compounds had a high concentration in the initial period, and decreased emissions as time lapsed. Acetaldehyde showed the highest concentration and was initially 78 ppm during the test period. Acetaldehyde was followed by propionic acid at 61 ppm, propanal at 51 ppm, and isobutanal at 50 ppm. As a result of comparing the occupational exposure limits (OELs) of individual VOC emitted during the coffee roasting process, the OELs of four substances, including acetaldehyde, propionic acid, acetic acid, and pyridine were identified. Of all four substances, only pyridine exceeded the OELs, and the other compounds had levels of 10% to 30% of the OELs.