• Title/Summary/Keyword: Decay rate

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Changes of Postharvest Quality and Microbial Population in Jujube-Shaped Cherry Tomato (Lycopersicon esculentum L.) by Stem Maintenance or Removal (수확 후 꼭지 유지, 제거에 따른 대추형 방울토마토의 품질 및 미생물 변화)

  • Choi, Ji Weon;Lee, Woo Moon;Do, Kyung Ran;Cho, Mi Ae;Kim, Chang Kug;Park, Me Hea;Kim, Ji Gang
    • Food Science and Preservation
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    • v.20 no.1
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    • pp.30-36
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    • 2013
  • Red-ripe 'Betatiny' jujube-shaped cherry tomato fruits via stem maintenance or stem removal were stored at $20^{\circ}C$ for 12 days. Their quality and microbial safety parameters like their respiration rate, weight loss, soluble solids content (SSC), titratable acidity (TA), firmness, hue value, aerobic microflora, coliform, yeast and mold count, and decay were evaluated during their storage. The jujube-shaped cherry tomato fruits whose stems were removed lost less weight than the fruits whose stems were maintained during their 12 days of storage. The stem removal lowered the respiration more significantly than the stem maintenance, and the formation of novel tissues at the stem scar that resulted from the stem removal was observed morphologically. The SSC, TA and hue value of the skin color decreased after eight storage days, but showed no difference between the stem maintenance and removal. The stem had higher microbial counts like aerobic microflora, coliform, and yeast and mold counts. The stem maintenance showed a short shelf-life because molds grew on the attached stem after five storage days. The shelf-life of the jujube-shaped cherry tomato fruits whose stems were removed was about eight days, but that of the fruits whose stems were maintained and that were stored at $20^{\circ}C$ was only about six days.

Effect of Packaging Materials and Storage Temperature on the Quality of Dried Lotus Root (Nelumbo nucifera G.) (포장재 및 저장온도에 따른 건조 연근의 품질특성)

  • Kwon, Oh-Heun;Ryu, Jung-A;Kang, Dong-Kyoon;Choe, So-Young;Lee, Hye-Ryun
    • Food Science and Preservation
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    • v.17 no.6
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    • pp.777-783
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    • 2010
  • The effects of packaging materials and storage temperature on the quality of dried lotus roots (NelumbonuciferaG.) were studied during 330 days of storage. Using four commercial types of packaging, (PE [polyethylene] film bags, PP [polypropylene] film bags, gunny roll, and paper bags), and four different storage temperatures (-5, 0, 10, and $20^{\circ}C$), changes in moisture content, hardness, color, and sensory qualities of dried lotus roots were investigated. The moisture contents of dried lotus roots stored in PE and PP film bags were higher than those of roots stored in gunny and paper bags. A major difference in moisture content was apparent when roots stored in gunny bags and paper bags were compared. Hue angle values were stable in roots stored in gunny and paper bags at all temperatures. Hardness decreased slightly with increased storage time in PE and PP film bags. Decay rate and marketability of roots stored in PE and PP film bags at $-5^{\circ}C$ were acceptable. The results showed that dried roots packaged with PE and PP were stable in quality, in contrast to roots stored in gunny and paper bags.

Time-dependent Evolution of Accretion Disk Mass in a Black Hole Microquasar Candidate A0620-00 (블랙홀 마이크로퀘이사 후보 A0620-00의 강착원반 질량의 시간적 진화)

  • Kim, Soon-Wook
    • Journal of the Korean earth science society
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    • v.29 no.7
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    • pp.579-585
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    • 2008
  • The time-dependent evolution of disk mass for outburst limit cycle in a black hole microquasar is calculated based on the non-linear hydrodynamic model of thermally unstable accretion disk. The physical parameters such as black hole mass, disk size and mass transfer rate are adopted to reproduce the historical 1975 outburst observed in a prototype black hole X-ray nova A0620-00. The time-dependent effect of irradiation from the central hot region to the disk is considered in two ways: direct irradiation and indirect irradiation reflected from hot accretion flow above the disk. The accretion disk thermal instability model can account for the bolometric luminosity appropriate to typical characteristics of system luminosity observed in X-ray transients during the whole cycle of the outburst evolution. The maximum mass of the accretion disk, ${\sim}4.03{\times}10^{24}g$, is achieved at the ignition of an outburst, and the minimum value, ${\sim}8.54{\times}10^{23}g$, is reached during the cooling decay to quiescence. The disk mass varies ${\sim}5$ times during outburst limit cycle.

Influence of Maturity of Fruit and Storage Condition on the Storability of Sweet Pepper in MA Storage (저장 환경과 숙기 정도가 파프리카 과실의 저장에 미치는 영향)

  • Choi, In-Lee;Kim, Il-Seop;Kang, Ho-Min
    • Journal of Bio-Environment Control
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    • v.17 no.4
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    • pp.319-324
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    • 2008
  • The sweet pepper (paprika) is one of the most important exported vegetable crops in Korea. This study evaluated the storability of sweet pepper fruits between 2 cultivars with different maturities under different storage conditions. The sweet peppers ('Special' and 'Fiesta') were grown in a rockwool hydroponic system, and harvested two different maturities: half-maturity and full-maturity levels. The sweet pepper fruits were stored in MA(non-ventilated) and non-MA(ventilated) conditions at 4 and $9^{\circ}C$ for 20 days. The storability of sweet pepper fruit was the highest in $4^{\circ}C$ MA conditions that remained 5% carbon dioxide and 10% oxygen during the storage. The ethylene concentration in MA condition showed $2{\sim}8{\mu}l/l$ regardless of storage temperatures, cultivars and maturities. The fruits packaged with non-ventilated film, showed lower weight loss, and higher firmness, and there was no different about decay ratio compared to the fruits packed ventilated film. The coloration of semi-matured fruit that colored 50% before storage progressed faster in non-ventilated packaging condition at $9^{\circ}C$, but their color did not changed as same as level of full-matured fruit. The electrolyte leakages and respiratory rate that estimated degree of chilling injury was highest in non-MA(ventilated) conditions of 'Special' full matured fruit placed at room temperature for 3 days following storage at $4^{\circ}C$ for 20 days. It may be suggested that sweet pepper fruit packed sealed (non-ventilated) film and stored at non-chilling temperature can be maintained better quality for long term storage.

Molecular Ecological Characterization of Wastewater Bacterial Communities in Response to Algal Growth (조류성장에 따른 하수 박테리아 군집 변화에 관한 분자생태학적 연구)

  • Lee, Ju-Youn;Lee, Jang-Ho;Park, Joon-Hong
    • Journal of Korean Society of Environmental Engineers
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    • v.33 no.11
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    • pp.847-854
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    • 2011
  • To deal with issues from global climate changes, renewable bioenergy has become important. Algae have been regarded as a good resource for biorefinery and bioenergy, and also have potential capability to remove nutrient and non-decompositional pollutants for wastewater advanced treatment. Although algal-bacterial ecological interaction would be a crucially important factor in using algae for wastewater advanced treatment and resource recovery from wastewater, very little is known about ecological interaction between algae and bacteria in a real wastewater environment. In this study, under a real municipal wastewater condition, we characterized wastewater pollutant treatability and bacterial communities in response to growth of Ankistrodesmus gracilis SAG278-2, which can grow in wastewater and has a high lipid contents. The growth of algal population using the wastewater was inhibited by increase in wastewater bacteria while bacterial survival and cellular decay rate were not influenced by the algal growth. Removals of recalcitrant organic matters and total nitrogen were improved in the presence of algal growth. According to T-RFLP and statistical analysis, algal growth affected time-course changes in bacterial community structures. The following 16S rRNA gene amplicon, cloning results showed that the algal growth changes in bacterial community structure, and that bacterial populations belonging to Sediminibacterium, Sphingobacterium, Mucilaginibacter genera were identified as cooperative with the algal growth in the wastewater.

Effects of Different Carbon Dioxide and Oxygen Concentration on the Quality of Oriental Melon during CA Storage (참외 CA저장시 $CO_2$$O_2$농도에 따른 품질 변화)

  • 이숙희;김창배;서영진;김찬용;윤재탁
    • Food Science and Preservation
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    • v.6 no.4
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    • pp.386-391
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    • 1999
  • Oriental melon was stored in controlled atmospheres(5, 10 or 15% CO$_2$in combination with 3 or 10% O$_2$) and air as control, and was analyzed half monthly during a 45-day storage for various quality Parameters. Oriental melon which stored in CA condition was lower in weight loss and decay rate than that stored in air. There was no significant difference in firmness by CO$_2$or O$_2$concentration during a month of storage. Fruits stored in 10% CO$_2$+3% O$_2$showed higher level of soluble solids, Vitamin C content and L value than other condition. And also comparatively lower endogenous ethanol accumulation and better state of quality was observed in that condition.

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Changes in Quality of Crown Daisy and Kale Washed with Cooled Electrolyzed Acid Water during Storage (저온처리 전해산화수로 세정한 쑥갓과 케일의 저장중 품질변화)

  • 정승원;정진웅;이승현;박노현
    • Food Science and Preservation
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    • v.6 no.4
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    • pp.417-423
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    • 1999
  • Quality changes of crown daisy and kale were investigated during storage at 10$^{\circ}C$ after washing with cooled electrolyzed acid water at 3 times in 2 min. Total count and coliform count of crown daisy and kale after immersion in electrolyzed acid water were decreased to 1/130 and 1/1,170 of non-immersed crown daisy and to l/870 and l/470 of non-immersed kale. However total count and coliform count were increased to the similar levels of non-immesed and tap water immersed one after 6 days of storage. Weight loss of crown daisy and ka1e were lower than others for 3 days of storage but higher than that of one after that time. Decay rate of crown daisy and kale immersed electrolyzed acid water showed lower than that of non-immersed and tap water immersed one for 6 days. In case of kale, rupture strength was higher than others at just after immersion and showed similar values after initial storage period. Color value of both crown daisy and kale showed high L, b and low a value in the order of electrolyzed acid water, tap water and non-treatment. Chlorophyll content of crown daisy and kale were lower than those of others just after immersion in electrolyzed acid water, but showed rapid reduction in the order of non-treatment. tap water and electrolyzed acid water after 6 days. Overall organoleptic properties of crown daisy and kale in immersion electrolyzed acid water were higher than those of others.

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Comparative Evaluation of Radioactive Isotope in Concrete by Heavy Ion Particle using Monte Carlo Simulation (몬테카를로 시뮬레이션을 통한 중하전입자의 콘크리트 방사화 비교평가)

  • Bae, Sang-Il;Cho, Yong-In;Kim, Jung-Hoon
    • Journal of radiological science and technology
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    • v.44 no.4
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    • pp.359-365
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    • 2021
  • A heavy particle accelerator is a device that accelerates particles using high energy and is used in various fields such as medical and industrial fields as well as research. However, secondary neutrons and particle fragments are generated by the high-energy particle beam, and among them, the neutrons do not have an electric charge and directly interact with the nucleus to cause radiation of the material. Quantitative evaluation of the radioactive material produced in this way is necessary, but there are many difficulties in actual measurement during or after operation. Therefore, this study compared and evaluated the generated radioactive material in the concrete shield for protons and carbon ions of specific energy by using the simulation code FLUKA. For the evaluation of each energy of proton beam and carbon ion, the reliability of the source term was secured within 2% of the relative error with the data of the NASA Space Radiation Laboratory(NSRL), which is an internationally standardized data. In the evaluation, carbon ions exhibited higher neutron flux than protons. Afterwards, in the evaluation of radioactive materials under actual operating conditions for disposal, a large amount of short-lived beta-decay nuclides occurred immediately after the operation was terminated, and in the case of protons with a high beam speed, more radioactive products were generated than carbon ions. At this time, radionuclides of 44Sc, 3H and 22Na were observed at a high rate. In addition, as the cooling time elapsed, the ratio of long-lived nuclides increased. For nonparticulate radionuclides, 3H, 22Na, and for particulate radionuclides, 44Ti, 55Fe, 60Co, 152Eu, and 154Eu nuclides showed a high ratio. In this study, it is judged that it is possible to use the particle accelerator as basic data for facility maintenance, repair and dismantling through the prediction of radioactive materials in concrete according to the cooling time after operation and termination of operation.

Preparation and characterization of Mn doped copper nitride films with high photocurrent response

  • Yu, Aiai;Hu, Ruiyuan;Liu, Wei;Zhang, Rui;Zhang, Jian;Pu, Yong;Chu, Liang;Yang, Jianping;Li, Xing'ao
    • Current Applied Physics
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    • v.18 no.11
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    • pp.1306-1312
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    • 2018
  • The Mn-doped copper nitride ($Cu_3N$) films with Mn concentration of 2.0 at. % have high crystallinity and uniform surface morphology. We found that the as-synthesized Mn-doped $Cu_3N$ films show suitable optical absorption in the visible region and the band gap is ~1.48 eV. A simple photodetector based on Mn doped $Cu_3N$ films was firstly fabricated via magnetron sputtering method. The fabricated device with doping of Mn demonstrated high photocurrent response and fast response shorter than 0.1 s both for rise and decay time superior to the pure $Cu_3N$. Furthermore, the energy levels of Mn-doped Cu3N matched well with ITO and Ag electrode. The excellent photoelectric properties reflect a good balance between sensitivities and response rate. Our investigation reveals the excellent potential of Mn-doped $Cu_3N$ films for application of photodetectors.

Characteristics Analysis of Burned tree by Terrestrial LiDAR in Forest Fired Area of Pinus densiflora (지상라이다를 활용한 소나무 산불피해지의 임목 피해특성 분석)

  • Kang, Jin-Taek;Ko, Chi-Ung;Yim, Jong-Su;Lee, Sun-Jeoung;Moon, Ga-Hyun;Lee, Seung-Hyun
    • Korean Journal of Remote Sensing
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    • v.36 no.6_1
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    • pp.1291-1302
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    • 2020
  • To verify the field-effectiveness of Terrestrial Laser Scanner (TLS), a terrestrial LiDAR was deployed to examine the damage properties of woods in forest fire area, then the data was compared with the results surveyed by a forestry expert. Four sample plots (30 m × 50 m, 0.15 ha) were set from the foot to the top of the mountain, and DBH, height, clear length, burned height, and crown length were investigated. Next, TLS collected information on damage characteristics found in the sample plots. This information was then compared with that amassed by the expert. The expert and the TLS survey results showed 30.8 cm and 29.9 cm for DBH, 15.8 m and 17.5 m for tree height, 8.4 m and 8.4 m for clear length, 4.0 m, 3.5 m for burned height, and 7.4 cm and 9.1 cm for crown length. With the exceptions of height and clear length, no notable discrepancy was observed between two methods. H/D ratio, CL/H ratio, and BH/CL ratio, all of which contribute to stability and decay rate of the stand, from the two methods were also compared. The human survey rated each ratio (H/D, CL/H, BH/CL in order) 51.3%, 47.1%, and 53.6%, while the TLS presented the results of 58.8%, 52.0%, and 38.7%.