• The Korean Journal of Food And Nutrition
• /
• v.30 no.3
• /
• pp.591-598
• /
• 2017

To prolong the shelf-life of strawberry, samples were treated with gel packs containing slow-released chlorine dioxide($ClO_2$) gas at 3~7 ppm for 6 days at room temperature. The weight loss and decay ratio as well as changes in pH, color and texture properties of the treated samples were investigated. The weight of the control and $ClO_2$ gas treated samples decreased slightly, but the weight of the control changed faster than those of the $ClO_2$ gas treated samples during the storage period. The decay ratio of control was higher than those of the $ClO_2$ gas treatments since 4 days of storage. The pH and acidity in the control and in the $ClO_2$ gas treated samples were no differences during storage period. The lightness of strawberry decreased during storage, but there was no difference in lightness among the treatments even when storage time was extended. The redness and yellowness of the control showed higher change than those of the $ClO_2$ gas treatments during 6 days. The firmness of the control changed more rapidly than those of the $ClO_2$ gas treatments during 6 days. Especially, the samples treated 3 and 5 ppm $ClO_2$ gas were the least changed. And the scores for appearance, firmness and overall acceptance control and 7 ppm $ClO_2$ gas treatment decreased more rapidly than those of 3 and 5 ppm treatment.

• Korean Journal of Food Science and Technology
• /
• v.40 no.1
• /
• pp.1-7
• /
• 2008

Quality attributes of welsh onion (Allium fistulosum L.) as affected by harvest timing (November, December 2006 and January 2007) and storage temperature (5, 10 and $20^{\circ}C$) were investigated in terms of respiration rate, weight loss, decay rate, color, hardness, sensory quality. A higher respiration rate was found when welsh onions were harvested later and storage temperature was higher. A smaller weight loss was observed in welsh onions that were harvested in November and stored at temperature of $5^{\circ}C$, demonstrating a 9.35% reduction. In other words, there were a minimum difference of 2.15% and a maximum difference of 9.92% between the weight loss in test samples harvested in November and those of test samples harvested in other months. The decay rate was higher in welsh onions harvested in January. The degree of color was more stable in test samples kept at temperature of $5^{\circ}C$ than those kept at higher temperature (10 and $20^{\circ}C$). There were, however, no significant differences in color changes among test samples harvested at different times of the year. Thus color change is closely associated with temperature. Also, welsh onions were harvested in November and stored at temperature of $5^{\circ}C$ showed a good sensory quality.

• Korean Journal of Applied Biomechanics
• /
• v.16 no.1
• /
• pp.101-108
• /
• 2006

The purpose of this study was to compare GRF characteristics during walking wearing jogging and roller shoes. Twelve male middle school students (age: $15.0{\pm}0.0\;yrs$, height: $173.6{\pm}5.0\;cm$, weight: $587.6{\pm}89.3\;N$) who have no known musculoskeletal disorders were recruited as the subjects. Kinematic data from six S-VHS camcorders(Panasonic AG456, 60 fields/s) and GRF data from two force platform; (AMII OR6-5) were collected while subjects walked wearing roller and jogging shoes in random order at a speed of 1.1 m/s. An event sync unit with a bright LED light was used to synchronize the video and GRF recordings. GRF data were filtered using a 20 Hz low pass Butterworth. digital filter and further normalized to the subject's body weight. For each trial being analyzed, five critical instants and four phases were identified from the recording. Temporal parameters, GRFs, displacement of center of pressure (DCP), and loading and decay rates were determined for each trial. For each dependent variable, paired t-test was performed to test if significant difference existed between shoe conditions (p <.05). Vertical GRFs at heel contact increased and braking forces at the end of initial double limb stance reduced significantly when going from jogging shoe to roller shoe condition. Robbins and Waked (1997) reported that balance and vertical GRF are closely related It seems that the ankle and knee joints are locked in an awkward fashion at the heel contact to compensate for the imbalance. The DCP in the antero-posterior direction for the roller shoe condition was significantly less than the corresponding value for the jogging shoe condition. Because the subjects tried to keep their upper body weight in front of the hip to prevent falling backward, the DCP for the roller shoe condition was restricted The results indicate that walking with roller shoes had little effect on temporal parameters, and loading and decay rates. It seems that there are differences in GRF characteristics between roller shoe and jogging shoe conditions. The differences in GRF pattern may be caused primarily by the altered position of ankle, knee, and center of mass throughout the walking cycle. Future studies should examine muscle activation patterns and joint kinematics during walking with roller shoes.

• Food Science and Preservation
• /
• v.10 no.4
• /
• pp.441-446
• /
• 2003

Cherry tomatoes, cucumbers and zuchinis stored in the far-infrared radiated chamber at 5$^{\circ}C$ or 10$^{\circ}C$ under 90% of relative humidity had been maintained in the fresh state for longer times than the control stored only in the cold chamber. Vegetables stored in the far-infrared radiated chamber showed lower values in weight loss rate, microbial colony count and decay ratio and higher ascorbic acid content than the control stored cold in the cold room through the storage period. We confirmed that vegetables stored in the far-infrared radiated chamber under low temperature and high humidity showed least changes in quality properties through the storage period and the far-infrared radiated facilities could be a good storage system.

• Korean Journal of Organic Agriculture
• /
• v.10 no.3
• /
• pp.57-66
• /
• 2002

The experiment described in this paper focused on determining the effects of high-temperature(20$^{\circ}$) treatment of Satsuma mandarins, prior to their storage, on their color development and quality. High-temperature treatment promoted fruit skin color during the storage, decreased the weight loss regardless of their color at the time of their harvest and reduced the decay occurrence until the middle of March, but there was no difference between treatments after the end of March. There was a tendency of higher soluble solid and acid levels in the fruit when high-temperature treatment was applied but this difference was not significant.

• Journal of the Korea Furniture Society
• /
• v.11 no.1
• /
• pp.13-23
• /
• 2000

This study was carried out to investigate the wood properties for development the proper uses of lesser-known tree species. The tested species are Kebambang(Pentace sp.), Bawang-bawang(Dysoxylum alliaceum Bl .), Garu buaya( Gonystylus brunescens A. Shaw)grown in Indonesia. fundamental wood properties such as anatomical, physical, mechanical and chemical properties and characteristics related to wood processing were examined. The results are summarized as follows : The woods of these species are diffuse porous, coarse textured, and interlocked grained. The heartwood of Kebambang is distinguished clearly to the sapwood, but the heartwood of other species are not distinguished clearly to the softwood. The woods of Kebambang and Bawang-bawang have the moderate weight density and the low strength properties, but Garu buaya has the high weight density and the high strength properties. The woods of these species has high shrinkage. The sawing characteristics of Kebambang are excellent but the other species are moderate. The machining characteristics by planer and drying characteristics of these species are moderate. These woods has poor characteristics in bending processing and decay durability. The wood of Bawang-bawang has high content of the extractives and lignin.

• Nuclear Engineering and Technology
• /
• v.51 no.1
• /
• pp.284-292
• /
• 2019

For the continuous operation of a nuclear reactor, burnt fuel needs to be replaced with fresh fuel, where appropriate (ex-vessel) fuel handling is required. Particularly for the Sodium-cooled Fast Reactor (SFR) refueling, its process has unique challenges due to liquid sodium coolant. The ex-vessel spent fuel transportation should concern several design features such as the radiation shielding, decay-heat removal, and inert space separated from air. This paper proposes a new design optimization methodology of cask shielding to transport the spent fuel assembly in a prototype SFR for the first time. The Particle Swarm Optimization (PSO) algorithm had been applied to design trade-offs between shielding and cask weight. The cask is designed as a double-cylinder structure to block an inert sodium region from the air-cooling space. The PSO process yielded the optimum shielding thickness of 26 cm, considering the weight as well. To confirm the shielding performance, the radiation dose of spent fuel removed at its peak burnup and after 1-year cooling was calculated. Two different fuel positions located during transportation were also investigated to consider a functional disorder in a cask drive system. This study concludes the current cask design in normal operations is satisfactory in accordance with regulatory rules.

• Journal of Forest and Environmental Science
• /
• v.36 no.3
• /
• pp.225-232
• /
• 2020

Chemical modification of wood is an effective method to enhance the biological durability of wood with no toxic effect on the environment. In this study, wood of Triplochiton scleroxylon was modified using acetylation techniques. A total of one hundred wood blocks, (each 20×20×60 mm) obtained from a 22-year old T. scleroxylon tree were conditioned and acetylated at 120℃ in a bioreactor containing acetic anhydride for 60, 120, 180, 240 and 300 minutes. The percentage weight gain of acetylated wood was determined. The untreated (control) and treated blocks were exposed to Pleurotus ostreatus (white rot fungus) and Fibroporia vaillanti (brown rot fungus) after which moisture content (MC) and weight loss (WL) was monitored for 16 weeks. Data were analysed using descriptive and inferential statistics at p<0.05 level of significance. The percentage weight gain of acetylated wood samples increased with time from 10.4% (60 minutes) to 22.7% (300 minutes). MC of untreated blocks inoculated with Pleurotus ostreatus was significantly higher than those of Fibroporia vaillantii after 16 weeks exposure. There was no significant difference in the MC of the of the acetylated samples for the two fungi after 300 minutes reaction time. The WL of untreated blocks inoculated with Fibroporia vaillantii was higher than those of Pleurotus ostreatus, however, the two fungi showed no significant difference in the WL for the acetylated samples after 16 weeks exposure. Acetylation prevents moisture absorption and inhibition of fungi growth in acetylated wood compared to untreated wood, thereby enhancing the durability of Triplochiton scleroxylon.

• Analytical Science and Technology
• /
• v.15 no.3
• /
• pp.229-235
• /
• 2002

Plasma source ion implantation (PSII) technique was utilized to improve the wettability of polystyrene surfaces. It is well known that treated surfaces undergo aging, leading to hydrophobic recovery with time. We investigated the aging effect of polystyrene thin film on the various molecular weights. Polystyrenes with several molecular weights ($M_w$ = 760, 2430, 31600, 115700, 280000, 903600) were treated in different experimental conditions including gas species and pulse energy, and their hydrophilicity was measured by contact angle goniometer. To study wettability decay as a function of the molecular weight, PSII-treated samples were aged at different temperatures. Hydrophobic recovery of high molecular weight polystyrene was much slower than that of low molecular weight, even at high temperatures. The methods used to characterize treated surfaces were water contact angle measurement, TOF-SIMS, XPS, SEM and AFM.

• Membrane Journal
• /
• v.12 no.1
• /
• pp.21-27
• /
• 2002

The formation of soluble microbial products(SMP) and molecular weight distribution on loading rate were observed in batch-type culture medium, which phenol was fed as a substrate. The molecular weight destribution was obtained by using 30K, 100K dalton and $0.45{\mu}$ membrane filters. When the phenol concentrationas a substrate was 120, 230 and 440 mg/L , the specific substrate utilization rate(q) showed 0.639, 1.281 and 1.744 mgTOC/mgMLSS/day, respectively. The endogenous biomass decay rate constant($K_d$) at each substrate concentration was 0.00536, 0.0661 and 0.0749($day^1$), respectively. The $SMP_e$ product rate constant($k_{SMP}_ e$) showed 0.006, 0.0058 and 0.0057($day^1$), respectively. The initial influent substrate during the course of time degraded and produced $SMP_s$. The $SMP_s$ was converted to the $SMP_{nd}$ and endogenous phase converted to the $SMP_e$ ingredients. The molecula weight distribution on loading rate was converted to a higher MW during the course of time.