The present study analyzed the pore formation and development process in carbon black that was activated by CO2 gas and the effect of the burn-off (BO) ratio on the process, particularly based on changes in the surface shape and internal microstructure. The activation process was performed as follows. Carbon blacks were injected into a horizontal tube furnace when the inside temperature reached 1000 °C. Carbon black samples with different BOs, i.e., 7.2%, 15.4%, 30.4%, 48.2%, 59.9%, and 83.2%, were prepared by varying the activation time. The microstructure of the activated samples was observed and examined using SEM and TEM. The results showed that pore passages were first created on the surface of the primary particles of the carbon black, and then the inner portion of the carbon black with a lower degree of crystallinity started to be activated, thereby causing inner pores to be formed. These inner pores then started to grow and coalesce into larger pores, thereby causing the crystallite layers in the inner portion of the carbon black to be activated. The changes in the microstructure of the carbon black during the activation reaction were attributable to the carbon black manufacturing process, in which the nucleation and growth of the primary particles of the carbon black occurred within a very short period of time. Thus, the crystallization of the inner portion was suppressed, and therefore, the degree of crystallinity was lower in the inner portion than in the outer portion.
The O2 and CO2 concentrations in controlled atmosphere (CA) rooms are determined by the respiration of produce like apples and the airtightness of the CA room, with gas in the CA room controlled by O2 and CO2 removal as well as respiration (CO2 increase and O2 decrease). The purpose of this study was to evaluate the validity of the gas exchange model for O2 removal, CO2 removal, the rate of O2 decrease and CO2 increase by respiration of apples, and airtightness of the CA room. It took 17.5 hours to reduce O2 concentration from 20.9% to 2.0% after loading 4.3 tons of Fuji apples into the CA room, which was 4.2 hours longer than the 13.3 hours of the model formula. After the CO2 concentration rose to 0.5% due to respiration, it took 4.7 hours to lower the CO2 concentration to 0.2%, which was 0.6 hours longer than that of the model equation. The rate of CO2 increase by respiration was 0.021%/ h, which was similar to the model equation (0.017%/h). Also after 4.7 hours, the O2 concentration decreased by 0.1% which was also in line with the model equation (0.13%/h).
This study was conducted to develop and evaluate an appropriate control device for a purge type controlled atmosphere (CA) storage in Korea. To determine ideal performance, oxygen and carbon dioxide control capability and airtightness were analyzed according to the postharvest management manual of CA storage of Fuji apples. In shortened experiments for CA storage, the condition was delayed CA at 0-0.5oC for three days and stored at 0.1-0.5% carbon dioxide levels for 3 days and then further stored 6 days under 1% carbon dioxide. As a result, the temperature control range of a developed CA container was 0.0-0.5oC, and the relative humidity was more than 90%, except for the defrosting step for the freezer during the storage period. The rate of pressure reduction for the CA container in the negative and positive pressure states was 0.45 and 0.21 mmH2O/min, respectively, and it was twofolds higher than standard airtightness for CA storage. After nitrogen injection, oxygen concentration was achieved at 2%, and carbon dioxide concentration was maintained at 0.1-0.5% for 6 days. Afterwards, carbon dioxide levels were tightly controlled between 0.1-1.0%. These results suggest that a developed purge type CA container could be effective in commercially maintaining the quality of agricultural products.
This study was conducted to develop the domestic production of a controlled atmosphere (CA) storage system, including nitrogen generator and carbon dioxide eliminator using selective gas separation membrane and operating program. Generally, the gas composition inside general cold stores constantly changes due to the metabolic activity of the respiring vegetables and fruits and leakage of gases through doors and walls. However, the CA container developed by our research team is able to control of the level of oxygen and carbon dioxide inside the reefer, making it simple and effective in operation. The efficiency of the nitrogen generator to replace oxygen with nitrogen inside the CA container was approximately 1.33% per hour. The change in oxygen concentration inside the CA container during the operation refrigerator almost did not show any difference for 8 days. Therefore, CA storage container should be a promising approach to maintaining the high quality of agricultural products during storage.
The effect of increased carbon dioxide concentration in atmosphere was examined on the pheromone system of Helicoverpa armigera reared from egg stage to adult in three room. Two of three room (2×2×2 m) were treated with carbon dioxide gas as 600 ppm and 1,000 ppm, respectively. Mean of carbon dioxide concentration was 429.1 ppm in the control, 603.3 ppm for 600 ppm, and 1011.5 ppm for 1,000 ppm during experiment. Electroantenograph (EAG) test was conducted on 3-d-old male adults with air, hexane, and a series of their sex pheromone component, Z11-16Al, from 0.01 to 100 ng. The result was that male EAG responses of 600 and 1,000 ppm were 30.3% lower than that of control room. Production of Z11-16:Al was examined on about twenty 2-d-old virgin females. Carbon dioxide increases did not show a statistically significant difference. However, higher amount of sex pheromone was produced in females of 600 and 1,000 ppm. So, This experiment was replicated with different population reared again. The amount of the sex pheromone per female was 108.9 and 118.1 ng in control room, 139.8 and 141.8 ng in 600 ppm room, and 124.6 and 125.8 ng in 1,000 ppm room.
Cu(In, Ga)Se2 (CIGS) precursor films were electrodeposited on Mo/glass substrates in acidic solutions containingCu2+, In3+, Ga3+, and Se4+ ions at −0.6V (SCE) and pH 1.8. In order to induce recrystallization, the electrodepositedCu1.00In0.81Ga0.09Se2.08 (25.0at.% Cu+20.2at.% In+2.2at.% Ga+52.0at.% Se) precursor films were annealed under a highSe gas atmosphere for 15, 30, 45, and 60 min, respectively, at 500oC. The Se amount in the film increased from 52at.% to62at.%, whereas the In amount in the film decreased from 20.8at.% to 9.1at.% as the annealing time increased from 0 (as-deposited state) to 60 min. These results were attributed to the Se introduced from the furnace atmosphere and reacted withthe In present in the precursor films, resulting in the formation of the volatile In2Se. CIGS precursor grains with a cauliflowershape grew as larger grains with the CuSe2 and/or Cu2-xSe faceted phases as the annealing times increased. These faceted phasesresulted in rough surface morphologies of the CIGS films. Furthermore, the CIGS layers were not dense because the emptyspaces between the grains were not removed via annealing. Uniform thicknesses of the MoSe2 layers occurred at the 45 and60 min annealing time. This implies that there was a stable reaction between the Mo back electrode and the Se diffused throughthe CIGS film. The results obtained in the present research were sufficiently different from comparable studies where therecrystallization annealing was performed under an atmosphere of Ar gas only or a low Se gas pressure.
Lotus-type porous nickel with cylindrical pores was fabricated by unidirectional solidification under an Ar gas atmosphere using the thermal decomposition method of the compounds such as sodium hydroxide, calcium hydroxide, calcium carbonate, and titanium hydride. The decomposed gas does form the pores in liquid nickel, and then, the pores become the cylindrical pores during unidirectional solidification. The decomposed particles from the compounds do play a rule on nucleation sites of the pores. The behavior of pore growth was controlled by atmosphere pressure, which can be explained by Boyle's law. The porosity and pore size decreased with increasing Ar gas pressure when the pores contain hydrogen gas decomposed from calcium and sodium hydroxide and titanium hydride, ; however it they did not change when the pores contain containing carbon dioxide decomposed from calcium carbonate. These results indicate that nickel does not have the solubility of carbon dioxide. Lotus-type porous metals can be easily fabricated by the thermal decomposition method, which is superior to the conventional fabrication method used to pressurized gas atmospheres.
To examine the critical effect of oxygen concentration on embryonic development, in vitro fertilized embryos were cultured in media(TCM199 vs. SOF) supplemented sera(1O% FCS vs. 10% HS) with and without bovine oviduct epithelial cells under two gas atmosphere (5% in air vs. 5% , 5% , 90% ). Oocytes, obtained from abattoir ovaries, were matured in EGF containing TCM199 medium co-cultured with BOEC for 24 hours, followed by exposure to frozen-thawed, heparin4reated spermatozoa in TALP for 30 hours. And then early embryos(1~2 cell) were cultured in both TCM199 and SOF supplemented with 10% FCS or 10% RS under 5% in air or 5% COi, 5% , 90% . Development to morulae and blastocysts was recorded on days 7, after the start of in vitro fertilization. The developmental rates of in vitro fertilized embryos to morulae and blastocysts cultured in SOF with BOEC under 5% , 5% , 90% (24.4%) were significantly(p<0.05) higher than cultured in SOF with BOEC under 5% in air(14.1%) at seven days after in vitro fertilization. When early bovine embryos were cultured in TCM 199 and SOF under two different gas atmosphere, there were no significant differences in the developmental rates to morulae and blastocysts between supplements of 10% FCS and 10% HS. The rates of development to morulae and blastocysts were significantly(p<0.01) higher in TCM 199 with BOEC(24.7%) than TCM199 without BOEC(10.9%) under 5% in air, otherwise SOF without BOEC(36.4%) were significantly (p<0.05) higher than in SOF with BOEC (24.4%) under 5% , 5% , 90% . In summary, these experiments have proved that the culture system in SOF supplemented 10% ES is effective on in vitro development of early bovine embryos under 5% , 5% , 90% . In addition, it is effective to development of bovine embryos that TCM 199 should be co-cultured with BOEC and SOF should be cultured without somatic cells under two different gas atmosphere.
느타리버섯의 호흡속도 측정 및 MA 포장 저장 실험을 수행한 결과 호흡속도는 2에서 산소소비속도 28.9∼161.4mgO/kghr로 나타났으며 이산화탄소방출 속도는 53.4∼166.9mg/kghr로 나타났다. 산소소비속도와 이산화탄소발생속도를 반응표면분석한 결과를 이용하여 느타리버섯의 저장 가능 기체조성을 예측한 결과 2.5∼4.5% 와 11.5∼l3%로 나타났다. 포장내 기체조성은 0.03mmLDPE의 경우 농도 1.6∼3.0%, 농도 3.9