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Basic Study on BWR Plant Behavior under the Condition of Severe Accident (2)
Get PDFIn this paper, we report on the results using the BWR plant simulator about the plant behavior under the condition of the two types of severe accidents that LOCA occurs but ECCS fails the water irrigation into the reactor core and SBO occurs and at the same time the reclosed failure of SRV occurs. The simulation experiments were carried out for the cases that LOCA has occurred in the main feed-water piping. As for the results about the relationship between the LOCA area and the time from LOCA occurs until the fuel temperature rise start, the effect that RCIC operated was extremely big for small and middle LOCA area. In the case of main feed-water system LOCA, the core water level suddenly decreased for large LOCA of 2000cm2 area, however, if the irrigation into the reactor core was carried out 30min after LOCA occurrence, the core had little damage. In addition, the H2 concentration in the containment vessel did not exceed both limits of H2 explosion nor detonation. The pressure of the containment vessel was around 3kg/cm2 of design value, so the soundness of the containment vessel was confirmed. On the other hand, for the accident of SBO with reclosed failure of SRV, it has been shown that the accidents continue to progress rapidly as compared with the case of normally operating of SRV. Because SRV has the function that keep the inside pressure of reactor core by repeating opened and closed in response of the inside pressure and prevent the decrease of water level inside reactor core. However, if the irrigation into the reactor core was carried out 30min after SBO occurrence, the core had little damage and also the H2 concentration in the containment vessel did not exceed limits of H2 explosion. Further, as for the accident of reclosed failure of SRV, it has been shown that there are very good correspondence with the simulation results of main steam piping LOCA of area 180cm2 corresponding to the inlet cross-sectional area SRV installed on the piping. Therefore, the accident of reclosed failure has been also shown that can be regarded as small LOCA accidents of main steam piping.departmental bulletin pape
Effect of Oil Component on Hardness of Heat Curing Oil Film in Solid State
Get PDFThe heat curing oil film method using thermosetting property oil film is a new oil film method. The components of the oil paste in the heat curing oil film method are Silicone, Titanium dioxide, Oleic acid and Hardener. The heat curing oil film method, in which not only the plane flow pattern in wall surface but also oil film thickness of the steady flow can be measured, is developed by author. The heat curing oil film method is a very useful method for visualization of the steady air flow. The oil paste in the heat curing oil film method has been hardened with time from the sol to the gel by the hardener. The hardness of the heat curing oil film in the gel condition is measured by a rubber hardness meter and the effect of oil component on the hardness of the heat curing oil film in solid state is investigated in this paper.departmental bulletin pape
Relationship between Operating Conditions and Exhaust Gas Characteristics of Diesel Engines Using Bio Fuel
Get PDFBio Diesel Fuel (BDF) has attracted attention as a fuel alternative to petroleum. BDF contains a lot of oxygen, but the ignitability is inferior because the viscosity is high compared with gas oil. However, the previous researches found out that while gas oil and BDF are different fuel properties, the operating conditions to lose the remarkable difference of the thermal efficiency and the exhaust gas characteristic when using these with Diesel engines. That is, the effects that BDF has on the state of combustion and the exhaust gas characteristic of diesel engines are not clear. In this research, operation characteristics were examined while paying attention to the PM exhaust characteristic that changed by the combustion state by the performance examination of the diesel engine using BDF. As a result, it was clarified that more excellent operating characteristics during BDF use than when gas oil used can be obtained in the operating conditions with much supply fuel.departmental bulletin pape
Robot-mediated Indoor Exercise Promotion Program Which Has Some Amusement
Get PDFIn areas where it snows a lot in winter, the elderly people cannot go out for exercise, so that they have a loss of motor ability and high risk of falling. The falling is one of the causes of bedridden state. In order to solve this issue, we develop a system which can facilitate indoor exercises for the elderly people. In this system, we use compact-size mobile robot equipped with camera and virtual reality game for the exercise motivation. In this paper, we introduce what types of device are combined in order to construct the exercise system.departmental bulletin pape
A Study for an Image Processing System that Judges a Line of Rice Plants on the Weeding Robot “TAMBA"
Get PDFIncreased public interest in food safety and clean agriculture (e.g., ecological agriculture, organic culture and agrochemical-free cultivation) is driving a production system change from dependence on and use of agrochemicals toward their elimination. However, this raises a huge time- and labor-consuming problem with weeds. The weeding robot “TAMBA" decreases weeds in paddy fields without resorting to herbicides. "TAMBA" autonomously travels while avoiding rice plant rootstocks. Final goal is to runs on schedule, return to dock and recharge like “ROOMBA". In this time, we studied an image processing system on the weeding robot “TAMBA" that judges a line of rice plants in an ideal environment that only rice plants grew on a paddy field.departmental bulletin pape
Initial Results of Growth Diagnosis of Paddy-Field Rice Using Hyper-Spectral Camera in Growth Experiment of Oryza Sativa 'Koshihikari' Made in Fukui
Get PDFA growth experiment for developing better growth method of Oryza sativa 'Koshihikari' made in Fukui was carried out in 2015 by using 4 rice pods in a glass house under the collaboration with Fukui University of Technology, Fukui prefectural agricultural experiment station, Sakai agricultural high school and Yamada-Giken Co., Ltd. Our aim in the experiment was to make sure the effectiveness of hyper-spectral information ingrowth diagnosis of rice. As a first step for developing useful remote sensing technique to produce good taste rice in Fukui prefecture, we selected leaf color and content rate of protein in harvested rice as the targets of estimation. During the period of experiment, the leaf color of rice had been directly measured once a week by SPAD-502 which is well-used in-situ leaf color measurement instrument. Simultaneously, the spectral information of leaf had been observed by using a hyper-spectral camera HSC1702. In addition, the content rate of protein after the harvest was measured by Fukui prefectural agricultural experiment station. The result of correlation analyses between leaf color data and NDSI spectral indices derived from the hyper-spectral data shows that NDSI spectral indices using near-infrared and green wavelengths are effective for estimating leaf color of rice through different growing stages. The results also show that NDSI indices using reflectance of blue region are effective for estimation of content rate of protein. These results are basically consistent with those of previous studies, which indicates our measurement and data analyses were carried out successfully. However, a further study is needed to decide the optimal combination of wavelengths in NDSI index and to confirm the reproducibility of coefficient of regression line obtained in this study.departmental bulletin pape
A Study for Practical Use of Aerial Handwritten Character Recognition
Get PDFThis paper describes a method to recognize a character handwritten in the air. This recognition method uses the motion direction instead of positions of the device mounted on the hand. It also doesn't use the information of pen-up and pen-down. It selects and orders character candidates with DP (dynamic programming) matching. We prototyped a handwritten character recognition system that detect single character period by hovering in the air instead of adding some behavior for example, hand-open and hand-close. But this system is not enough to put it to practical use because it does not have easy functions to use. We intend to improve usability and work toward practical use of aerial handwritten character recognition by additional input method functions.departmental bulletin pape
Synthesis and Thermal Properties of Epoxy Resins Cured with Lignin-related Biphenols Having Syringyl Structure
Get PDF4,4'-Dihydroxy3,3',5,5'-teramethoxybiphenyl(DHTMB) was synthesized from syringol, which can be obtained by thermal and hydration degradation of lignin. As the model reaction for curing, octaethylene glycol diglycidyl ether was cured with DHTMB and also with4,4'-dihydroxybiphenyl (DHB) in the presence of 2-ethyl-4-methylimidazole (2E4MI).Curing reaction was studied by differential scanning calorimetry (DSC). The calculated activation energies (E's) were almost the same values for both curing systems. The mixture of epoxy compounds consisting of trimethylopropane triglycidyl ether and diethylene glycol diglycidyl ether was cured with DHTMB in the presence of 2E4MI. The above mixture of epoxy compounds was also cured with DHB. Thermal properties of cured epoxy resins were investigated by DSC. Glass transition temperature determined by DSC was 46.6℃ for that cured with DHTMB and 38.8℃ for that with DHB, suggesting that the existence of bulky methoxyl groups in syringyl structure restricts the main chain motion of cured epoxy resin.departmental bulletin pape
Study of Iodine Collection by Atmospheric Pressure Microwave Discharge Technique
Get PDFIn the event of a nuclear plant accident where the nuclear fuel has been damaged, radioactive iodine gaseous species can be released into the nuclear plant environment. However, extracting the iodine in a controlled manner to recover it and remediate the environment would require a more rigorous process. In this work, a microwave generated plasma is generated the iodine molecules (I2) from iodine compounds (CsI, KI etc.). An Argon gas based microwave generated plasma is used as the ionization chamber. The characteristics of the plasma and the iodine species is observed. Different forms of iodine (gas, liquid, solid) are released from the plasma zone downstream of the microwave chamber. The released gaseous species are capture in a filter system and the characteristics of the iodine species are identified. The results indicate that I2, I-, and I3-species are observed. The technique works well at ionizing the iodine species at relatively low powers and allowing them to be captured by a standard cotton filter. These results suggest that a microwave based technique may be useful for environmental cleanup activities of radioactive species such as iodine. The technique can be used to address contaminated material as well as treat the gas phase environment.departmental bulletin pape
Two-Photon Ionization of Benfluralin in the Presence of Cyclodextrin
Get PDFPhotoionization of benfluralin(N-butyl-N-ethyl-α, α, α-trifluoro-2, 6-dinitro-p-toluidine: Benf.) of typical agricultural chemical was achieved with two-photon two-step excitation by using 266-nm laser pulse irradiation in the presence of cyclodextrins (CDs). The formation of the Benf./CDs inclusion complex was studied by minimize energy of Molecular Mechanics program 2. Ionization of Benf. within the laser flash (5 ns)produced a radical cation of Benf. and hydrated electrons. The ionization quantum yield (Φion) of Benf. in the presence ofα-, β-and γ-CD calculated to be 6.2±0.1%, 16.0±1.0%and 3.3±0.1%, respectively, and it is due to the property of the Benf./CDs inclusion complex. The Φion of Benf. in the presence of CDs(1.0×10-2M)was dependent on the stabilization energy of solvation. In the case of CD concentration (1.0×10-3M),Φion of Benf. was also dependent on the stabilization energy of solvation. Additionally, we found that bulky substituted amino groups is important for the two-photon ionization (TPI)of agricultural chemical when compared with TPI of carbamate based agricultural chemicals. These results suggest the possibility of the photolysis of agricultural chemicals in aqueous solution by using TPI of UV light irradiation.departmental bulletin pape