• Korean Journal of Food Science and Technology
• /
• v.33 no.2
• /
• pp.200-204
• /
• 2001

Persimmon (Diospyros kaki. cv. Fuyu) fruits were packaged under different conditions, and then stored at $0^{\circ}C$ for 21 weeks. The tried packages were heat-sealed bag of one fruit, heat-sealed bag of five fruits, and tie-sealed bag of five fruits, which used films of three different thickness (0.03 ㎜, 0.05 ㎜ and 0.06 ㎜). Throughout the storage, package free volume, package atmosphere and quality were measured. Package free volume decreased with time with higher rate for heat-sealed bags, in which close contact between fruit and the film was eventually reached in longer storage. However, tie-sealed bags maintained the levels of stabilized free volume. The rate of free volume decrease was faster with thinner film and larger bag size for the packs sealed by the same method. Package atmosphere covered $O_2$ concentration of $1.1{\sim}17.1%$ and $CO_2$ concentration of $1.1{\sim}8.3%$, $O_2$ concentration decreased during storage, whereas $CO_2$ increased. Thinner film package created the internal atmosphere of higher $O_2$ and lower $CO_2$ concentrations. Tie-sealed bags of 5 fruits in the films of 0.05 mm and 0.06 mm thickness maintained the equilibrated package atmosphere of $1.1{\sim}3.0%\;O_2$ and $4.0{\sim}5.5%\;CO_2$, which preserved the fruits best in terms of firmness and less physiological changes of flesh browning and peel browning. At five fruit heat-sealed bag in the films of 0.06 mm thickness with $CO_2\;8.3%$, flesh browning occurred at a high rate, whereas all treatments in the film of 0.03 mm thickness with high $O_2$ and relatively low $CO_2$ contents, flesh and peel browning rates were high.

• Korean Journal of Food Science and Technology
• /
• v.15 no.2
• /
• pp.150-154
• /
• 1983

Mushroom, Lentinus edodes which had been dried at $50^{\circ}C$ for 20 hours were extracted with small amount of ethanol, methanol, chloroform and petroleum ether, respectively. The extracts were then dissolved in edible soybean oil, and the resulting substrates and a portion of the soybean oil (control) were placed in an incubator $(37.0{\pm}1.0^{\circ}C)$ for eight weeks. Peroxide values and TBA values of control and the substrates were determined regularly during the storage period. The results of the present study were as follows: 1. The moisture contents of the mushroom which was 84.88% on wet basis at the time of harvest were reduced to 15.12% after drying. 2. Extracts obtained from alcohols were effective in retarding the POV development. 3. There was not much difference among the TBA values after 14 days, but significant difference of the TBA values in control and the substrates extracts were observed in longer storage period TBA values of substrate containing ethanol and methanol in the later stage period were smaller than that of the substrates containing petroleum ether and chloroform. 4. In view of the POV and TBA value development, ethanol and methanol were more effective solvents for the extraction of antioxidant compounds in the dried mushroom than chloroform and petroleum ether.

• Horticultural Science & Technology
• /
• v.33 no.3
• /
• pp.375-382
• /
• 2015

A controlled atmosphere (CA) regimen was optimized during 3 consecutive harvest seasons as the basis of practical modified atmosphere packaging (MAP) storage for quality maintenance and extension of storage potential of fresh Ligularia fischeri leaves. Leaves were harvested in April or May and forced-air cooled to $4^{\circ}C$ before punch-hole MAP (control, where gas concentrations were same as air) and CA treatments. CA regimens adjusted stepwise during 3 experimental years were: 1 and 3% $O_2$, respectively combined with 5 and 10% $CO_2$ in the first year, 3% $O_2$ fixed in combination with 0, 2.5, and 5% $CO_2$ in the second year, and 3% $O_2$ fixed in combination with 2.5 and 5% $CO_2$ in the third year. In the first year, higher incidence of black discoloration was observed with the reduction of respiration under 10% $CO_2$ CA conditions regardless of $O_2$ levels at 1 or 3%. In the second and third year, the incidence of the disorder seemed not to be clearly relevant to CA conditions showing slightly higher incidence only after 4- or 5-week storage + 5-day shelf life. Although texture and appearance quality were maintained better under the 3% $O_2$ + 2.5% $CO_2$condition after 4-week storage + 5-day shelf life, effects of CA on the extension of storage period was slight. Overall results indicated that Ligularia fischeri leaves are very susceptible to $CO_2$ injury. $CO_2$ concentration should be adjusted below 2.5% for safe and effective CA or MAP storage to maintain quality even during short-term storage.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.45 no.2
• /
• pp.230-238
• /
• 2016

This study examined the effects of freezing and thawing conditions on quality of Hanwoo bottom round. The beef samples were frozen by air blast freezing at $-20^{\circ}C$ or ethanol immersion freezing at $-70^{\circ}C$ and then stored at $-20^{\circ}C$ for 10 days. After 10 days of storage, the frozen samples were thawed with air blast thawing at $4^{\circ}C$ or water immersion thawing at $4^{\circ}C$ and subjected to subsequent analyses of drip loss, water holding capacity, thiobarbituric acid reactive substance (TBARS), volatile basic nitrogen (VBN), total aerobic bacteria, and microstructure. Drip loss significantly increased in samples treated with air blast freezing compared to ethanol immersion freezing, whereas freezing and thawing processes had no significant impact on water holding capacity of the samples. Thawing conditions had a much stronger influence on the TBARS and VBN of the samples than freezing conditions. There was no significant difference in the population of total aerobic bacteria among the four samples subjected to one freeze-thaw cycle. In addition, to analyze the effects of freeze-thaw cycle on the quality of beef, three freeze-thaw cycles were performed during storage. Multiple freeze-thaw cycles increased drip loss, TBARS, and VBN and decreased water holding capacity, accelerating microstructural damage. These data indicate that Hanwoo bottom round can be rapidly frozen and thawed by using ethanol immersion freezing and water immersion thawing methods with minimal impact on meat quality.

• Radiation Oncology Journal
• /
• v.28 no.3
• /
• pp.166-176
• /
• 2010

Purpose: To determine the appropriate prostate planning target volume (PTV) margins for 3-dimensitional (3D) conformal radiotherapy (CRT) and intensity-modulated radiation therapy (IMRT) patients treated with an endorectal balloon (ERB) under our institutional treatment condition. Materials and Methods: Patients were treated in the supine position. An ERB was inserted into the rectum with 70 cc air prior to planning a CT scan and then each treatment fraction. Electronic portal images (EPIs) and digital reconstructed radiographs (DRR) of planning CT images were used to evaluate inter-fractional patient's setup and ERB errors. To register both image sets, we developed an in-house program written in visual $C^{++}$. A new method to determine prostate PTV margins with an ERB was developed by using the common method. Results: The mean value of patient setup errors was within 1 mm in all directions. The ERB inter-fractional errors in the superior-inferior (SI) and anterior-posterior (AP) directions were larger than in the left-right (LR) direction. The calculated 1D symmetric PTV margins were 3.0 mm, 8.2 mm, and 8.5 mm for 3D CRT and 4.1 mm, 7.9 mm, and 10.3 mm for IMRT in LR, SI, and AP, respectively according to the new method including ERB random errors. Conclusion: The ERB random error contributes to the deformation of the prostate, which affects the original treatment planning. Thus, a new PTV margin method includes dose blurring effects of ERB. The correction of ERB systematic error is a prerequisite since the new method only accounts for ERB random error.

• Journal of Mushroom
• /
• v.18 no.4
• /
• pp.317-322
• /
• 2020

This experiment was conducted to solve the failure of fruiting body production in the bottle cultivation of the oyster mushroom cultivar 'Heuktari'. The effects of incubation temperature on primordium formation and fruiting body yield of the oyster mushroom cultivar 'Heuktari' were investigated. The proper temperature for mycelium growth of 'Heuktari' on potato dextrose agar (PDA) medium is 23-26℃. The mycelial growth of 'Heuktari' was faster than that of Chunchu 2ho. During mycelial culture in sawdust medium, the temperature of the medium in the bottle initially increased, reached the highest point in the middle of the culture, and then decreased. The higher the set temperature, the shorter the incubation period. When the incubation temperatures were 20℃ and 24℃, respectively, the undeveloped primordium formation rates were low (1.8% and 4.2%, respectively). However, the rate of undeveloped primordium formation increased, and the yield decreased at incubation temperatures of 16℃ and 28℃. Mushroom farms that set incubation temperatures to 18℃ and maintained the medium temperature at less than 28℃ showed undeveloped primordium formation rates ranging between 0.3-0.8%. The rate of undeveloped primordium formation increased and the yield decreased in the farms with high incubation temperatures (above 28℃). We found that in order to reduce undeveloped primordium formation, the air inside the incubation room should be circulated continuously so that the temperature of the medium does not rise above 28℃, and dense incubation conditions should be avoided.

• Journal of Korean Society of Forest Science
• /
• v.9 no.1
• /
• pp.1-44
• /
• 1969

The important results which have been obtained in the investigation can be recapitulated as follows. 1. As demostrated by the experimental results and analyses concerning their effects in the on-ground type mushroom house, the constructions in relation to the side wall and ceiling of the experimental houses showed a sufficient heat insulation on effect to protect insides of the houses from outside climatic conditions. 2. As the effect on the solar type experimental mushroom house which was constructed in a half basement has been shown by the experimental results and analyses, it has been proved to be effective for making use of solar heat. However there were found two problems to be improved for putting solar houses to practical use in the farm mushroom growing: (1) the construction of the roof and ceiling should be the same as for the on-ground type house, and (2) the solar heat generating system should be reconstructed properly. A trial solar heat generating system is shown in Fig. 40. 3. Among several ventilation systems which have been studied in the experiments, the underground earthen pipe and ceiling ventilation, and vertical side wall and ceiling ventilation systems have been proved to be most effective for natural ventilation. 4. The experimental results have shown that ventilation systems such as the vertical side wall and underground ventilation systems are suitable to put to practical use as natural ventilation systems for farm mushroom houses. These ventilation systems can remarkably improve the temperature of fresh air which is introduced into the house by heat transfers within the ventilation passages, so as to approach to the desired temperature of the house without any cooling or heating operation. For example, if it is assuming that x is the outside temperature and y is the amount of temperature adjustment made by the influence of the ventilation system, the relationships that exist between x and y can be expressed by the following regression lines. Underground iron pipe ventilation system ${\cdots}{\cdots}$ y=0.9x-12.8 Underground earthen pipe ventilation system ${\cdots}{\cdots}$y=0.96x-15.11 Vertical side wall ventilation system${\cdots}{\cdots}$ y=0.94x-17.57 5. The experimental results have shown that the relationships existing between the admitted and expelled air and the $Co_2$ concentration can be described with experimental regression lines or an exponent equation as follows: 1) If it is assumed that x is an air speed cm/sec. and y is an expelled air speed in cm/sec. in a natural ventilation system, since the y is a function of the x, the relationships that exist between x and y can be expressed by the regression lines shown below: 2) If it is assumed that x is an admitted volume of air in $m^3/hr$ and y is an expelled volume of air in $m^3/hr$ in a natural ventilation system, since the y is a function of the x, the relationships that exist between x and y can be expressed by the regression lines shown below. 3) If it is assumed that the expelled air speed in cm/sec and replacement air speed in cm/sec. at the bed surface in a natural ventilation system are shown as x and y, respectively, since the y is a function of the x, the relationships that exist between x and y can be expressed by the following regression line: G.E. (100%)- C.V. (50%) ventilation system${\cdots}$ y=0.54X+0.84 4) If it is assumed that the replacement air speed in cm/sec. at the bed surface is shown as x, and $CO_2$ concentration which is expressed by multiplying 1000 times the actual value of $CO_2$ % is shown as y, in a natural ventilation system, since the y is a function of the x the relationships that exist between x and y can be expressed by the following regression line: G.E. (100%)- C.V. (50%) ventilation system${\cdots}{\cdots}$ y=114.53-6.42x 5) If it is assumed that the expelled volume of air is shown as x and the $CO_2$ concentration which is expressed by multiplying 1000 times the actual of $CO_2$ % is shown as y in a natural ventilation system, since the y is a function of of the x, the relationships that exist between x and y can be expressed by the following exponent equation: G.E. (100%)-C.V. (50%) ventilation system${\cdots}{\cdots}$ $$y=127.18{\times}1.0093^{-X}$$ 6. The experimental results have shown that the ratios of the crass sectional area of the G.E. and C.V. vent to the total cubic capacity of the house, required for providing an adequate amount of air in a natural ventilation system, can be estimated as follows: G.E. (admitting vent of the underground ventilation)${\cdots}{\cdots}$ 0.30-0.5% (controllable) C.V. (expelling vent of the ceiling ventilation)${\cdots}{\cdots}$ 0.8-1.0% (controllable) 7. Among several heating devices which were studied in the experiments, the hot-water boilor which was modified to be fitted both as hot-water toiler and as a pressureless steam-water was found most suitable for farm mushroom growing.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.48 no.5
• /
• pp.80-88
• /
• 2020

With the issuance of one-week fine dust emergency reduction measures in March 2019, the public's anxiety about fine dust is increasingly growing. In order to assess the application of air purifying plant-based bio-filters to public facilities, this study presented a method for measuring pollutant reduction effects by creating an indoor environment for continuous discharge of particle pollutants and conducted basic studies to verify whether indoor air quality has improved through the system. In this study conducted in a lecture room in spring, the background concentration was created by using mosquito repellent incense as a pollutant one hour before monitoring. Then, according to the schedule, the fine dust reduction capacity was monitored by irrigating for two hours and venting air for one hour. PM₁₀, PM_2.5, and temperature & humidity sensors were installed two meters front of the bio-filters, and velocity probes were installed at the center of the three air vents to conduct time-series monitoring. The average face velocity of three air vents set up in the bio-filter was 0.38±0.16 m/s. Total air-conditioning air volume was calculated at 776.89±320.16㎥/h by applying an air vent area of 0.29m×0.65m after deducing damper area. With the system in operation, average temperature and average relative humidity were maintained at 21.5-22.3℃, and 63.79-73.6%, respectively, which indicates that it satisfies temperature and humidity range of various conditions of preceding studies. When the effects of raising relatively humidity rapidly by operating system's air-conditioning function are used efficiently, it would be possible to reduce indoor fine dust and maintain appropriate relative humidity seasonally. Concentration of fine dust increased the same in all cycles before operating the bio-filter system. After operating the system, in cycle 1 blast section (C-1, β=-3.83, β=-2.45), particulate matters (PM₁₀) were lowered by up to 28.8% or 560.3㎍/㎥ and fine particulate matters (PM_2.5) were reduced by up to 28.0% or 350.0㎍/㎥. Then, the concentration of find dust (PM₁₀, PM_2.5) was reduced by up to 32.6% or 647.0㎍/㎥ and 32.4% or 401.3㎍/㎥ respectively through reduction in cycle 2 blast section (C-2, β=-5.50, β=-3.30) and up to 30.8% or 732.7㎍/㎥ and 31.0% or 459.3㎍/㎥ respectively through reduction in cycle 3 blast section (C-3, β=5.48, β=-3.51). By referring to standards and regulations related to the installation of vegetation bio-filters in public facilities, this study provided plans on how to set up objective performance evaluation environment. By doing so, it was possible to create monitoring infrastructure more objective than a regular lecture room environment and secure relatively reliable data.

• Journal of Animal Environmental Science
• /
• v.10 no.3
• /
• pp.141-154
• /
• 2004

The solar powered water pump is very ideal equipment because solar power is more intensive when the water is more needed in summer and it is very helpful in the rural area, in which the electrical power is not available. The average so]ar radiation energy is 3.488 kWh/($m^2{\cdot}day$) in Korea. In this study, the automatic control logic and system of the water pump driven by the radiation energy were studied, designed, assembled, tested and analyzed for realizing the solar powered water pump. The experimental system was operated automatically and the cycle was continued. The average quantity of the water pumped per cycle was about 5,320 cc. The cycle time was about 4.9 minutes. The thermal efficiency of the system was about $0.030\%$. The pressure level of the n-pentane vapour in flash tank was 150$\%$450 hPa(gauge) which was set by the computer program for the control of the vapour supply. The pressure in the condenser and air tank during cycles was maintained as about 600 hPa and 1,200 hPa respectively. The water could be pumped by the amount of 128kg/($m^2{\cdot}day$) with the efficiency of $0.1\%$ and the pumping head of 10 m for the average solar energy in Korea.

• Journal of the Korea Concrete Institute
• /
• v.16 no.6 s.84
• /
• pp.805-811
• /
• 2004

In this paper, effects of mixture proportion and material condition on both fundamental properties, drying and autogenous shrinkage of high performance concrete are discussed. According to the results, for the effect of mixture proportion on the fundamental properties, decrease in W/B and unit water content results in reduction of fluidity, while air content has no variation. Compressive strength exhibits an decreasing tendency with an increase in W/B and unit water content do not remarkable affect the compressive strength. For the effect of materials on the fluidity, the fluidity of low heat portland cement(LPC) is smaller than that of ordinary portland cement(OPC). The use of Polycarbonic acid based superplasticizer(PS) has more favorable effect on enhancing fluidity than Naphtalene based superplasticlzer(NS) and Melamine based superplasticizer(MS). Air content of concrete using LPC is larger than that using OPC. The effects of superplasticizer type on the air content is larger in order of MS, PS and NS. The use of LPC exhibited lower strength development at early age than OPC, whereas after 91days, similar level of compressive strength is achieved regardless of cement type. Compressive strength of concrete is not affected by SP type. For the effect of mixture proportion and materials on drying and autogenous shrinkage, an increase in W/B results in reduction of drying shrinkage and an decrease in water content leads to reduce drying shrinkage. Autogenous shrinkage is not observed until 49 days with the concrete mixture with $35\%$ of W/B and $145 kg/m^3$ of water content. This is due to the combination effects of expansion admixture and shrinkage reducing admixture, which causes an offset of autogenous shrinkage. The use of LPC results in a reduction in autogenous shrinkage compared with OPC. SP type has little influence on the autogenous shrinkage. It is found from the results that mixture proportioning of high performance concrete incorporating fly ash, silica fume, expansion admixture and shrinkage reducing admixture is need to focus on the increase in W/B and the reduction in water content and the use of LPC and MS is also required to use to secure the stability against shrinkage properties.