Effect of Prefilmer Edge Thickness on Spray Characteristics in Prefilming Airblast Atomizer

( Naoki Katagata ),( Toshihiro Sakaki ),( Takahiro Okabe ),( Takao Inamura ),( Koji Fumoto ),( Minori Shirota ) 한국액체미립화학회 2017 한국액체미립화학회 학술강연회 논문집 Vol.2017 No.-

A prefilming airblast atomizer is a fuel injector used in aircraft gas turbines. The atomization mechanism of the atomizer is well known. After injection, the liquid homogeneously wets the prefilmer surface, and flows down to the prefilmer edge in the form of a liquid film that is sheared by the high-speed air stream. The accumulated liquid at the prefilmer edge is sheared by the air and disintegrated into the bag-shaped liquid framed by a thicker rim. The bag-shaped part of the structure bursts into fine droplets. The rim is stretched and fragments into two elongated ligaments that disintegrate into larger droplets than those generated by bag-shaped disintegration. We focused on the effect of the prefilmer edge thickness on the breakup phenomena of the liquid film and the spray characteristics. Our previous study showed that there is a correlation between the edge thickness and the breakup length and breakup frequency. The objective of this study is to clarify the effect of the prefilmer edge thickness on the spray characteristics such as the Sauter mean diameter (SMD) and the spray generation frequency. The SMD at three prefilmer edge thicknesses (160, 500, and 2000 ㎛) under various conditions were observed using a high-speed camera and an image processing technique. The measurement position from the prefilmer edge was widely varied. The fast Fourier transformation (FFT) analysis was also conducted to evaluate the periodicity of the SMD. The experimental results showed that the SMD increases as the prefilmer edge becomes thicker. In the wake region of the edge, the FFT analysis showed that the increase in prefilmer edge thickness causes the transition of the maximal power spectrum to a lower frequency (i.e. less than 100Hz) due to the larger volume of a liquid accumulation attaching to the edge.

A new strategy to protect Katsura-uri (Japan's heirloom pickling melon, Cucumis melo var. conomon) from extinction

Azusa Sasaki,Yasushi Nakamura,Yukiko Kobayashi,Wataru Aoi,Takako Nakamura,Koji Shirota,Noboru Suetome,Michiaki Fukui,Tomoaki Shigeta,Tomoaki Matsuo,Shigehisa Okamoto,박은영,Kenji Sato 한국식품연구원 2017 Journal of Ethnic Foods Vol.4 No.1

Preparation of contemporary dishes and a functional drink using Japan's heirloom vegetable, Katsura-uri

Azusa Sasaki,Yasushi Nakamura,Yukiko Kobayashi,Wataru Aoi,Takako Nakamura,Koji Shirota,Noboru Suetome,Michiaki Fukui,Tomoaki Matsuo,Shigehisa Okamoto,Yuri Tashiro,Eun Y. Park,Kenji Sato 한국식품연구원 2018 Journal of Ethnic Foods Vol.5 No.1

Background The fruit of Katsura-uri, traditionally used in the preparation of pickles in Japan, is facing an extinction crisis. In addition to the traditional dishes prepared from Katsura-uri, alternative dishes using the fruit should be devised to increase consumer demands for the protection of the heirloom vegetable. We attempted designing new Katsura-uri contemporary dishes and assessed the application of Katsura-uri juice as a functional drink without raising blood glucose levels. Methods Cooking experiments were conducted with Katsura-uri in its ripening stages, based on the advice from a licensed chef and a registered dietitian in Japan. In the questionnaire-based sensory evaluation, consumer acceptability of Katsura-uri juice was assessed. The blood glucose levels were measured after healthy volunteers consumed the juice. Results We demonstrated six new Katsura-uri dishes. In the questionnaire-based sensory evaluation of Katsura-uri juice, the assessment values for taste and fragrance were high. In human trials, the levels of incremental area under the curve and glucose spike were significantly lower after consumption of Katsura-uri juice, as compared to those after consumption of muskmelon juice. Conclusion Katsura-uri-containing contemporary dishes and juice would help continue the consumption of the vegetable. Based on the results of the questionnaire, we also concluded that the use of Katsura-uri as a functional drink without raising blood glucose levels is superior to its use as contemporary dishes. These findings provide useful strategies to protect Katsura-uri from extinction.

Protection of Kyo-yasai (heirloom vegetables in Kyoto) from extinction: a case of Sabaka-daikon (Japan's heirloom white radish, Raphanus sativus) in Maizuru, Japan

Takako Nakamura,Yasushi Nakamura,Azusa Sasaki,Masami Fujii,Koji Shirota,Yutaka Mimura,Shigehisa Okamoto 한국식품연구원 2017 Journal of Ethnic Foods Vol.4 No.2

As a general background, Sabaka-daikon, one of the heirloom vegetables in Kyoto, ceased its commercial cultivation in the late 1960s at north Kyoto, leading to an extinction crisis. We review the activities of the local residents to revive the commercial cultivation of Sabaka-daikon from 2010. We also discuss the significance of the information on the health benefits of local foods in motivating local residents to protect local foods from extinction. For methodology, through field interviews of administrative members, venders, and farmers in Maizuru city, we explore reasons for the success in reviving a local heirloom vegetable, Sabaka-daikon. We also apply chemical analysis to determine individual differences in the anticarcinogenic (cancer preventive) compound, 4-methylthio-3-butenyl isothiocyanate, in Sabaka-daikon to guarantee its added health benefits. As a result, the primary factors for the revival of Sabaka-daikon in Maizuru city include the passion of farmers, measures undertaken by the local administration, and the marketing strategies of venders. The secondary factor is the fact that one primary factor (passion of farmers) coincides on a time axis with the other two factors (administrative measures and marketing strategies of venders). Wide individual differences in the anticarcinogenic compound, 4-methylthio-3-butenyl isothiocyanate, were observed, likely due to the variable genome of Sabaka-daikon. In conclusion, the results imply that the information on the health benefits of daikon contribute to motivating the local residents (i.e., passion of farmers) in protecting Sabaka-daikon from extinction. Revival of this heirloom vegetable would contribute to the diversification of local foods, and to the preservation of those foods and the cooking knowledge for future generations. As Sabaka-daikon variety has some races in variation of 4-methylthio-3-butenyl isothiocyanate production, a race with a fixed amount of 4-methylthio-3-butenyl isothiocyanate should be established to guarantee added health benefits of Sabaka-daikon.

Nationwide distribution of Kyo-yasai (heirloom vegetables in Kyoto) and the advantages of traditional farming methods with importance of ‘Syun’: a case of mizuna

Nakamura Takako,Nakao Asuka,Watanabe Minami,Ueda Kinji,Matsuda Toshihiko,Matsumoto Seiji,Yamaguchi Toshiharu,Haikata Masaho,Kaneko Asuka,Shirota Koji,Sasaki Azusa,Okamoto Shigehisa,Nakamura Yasushi 한국식품연구원 2022 Journal of Ethnic Foods Vol.9 No.-

Introduction: This study aimed to review the farming activity and the administrative measure to successfully increase the distribution of heirloom vegetable “mizuna” nationwide by examining the paradigm shift in the use of its young less-branched form for salad. We also discussed that breeding programs of the young form ironically resulted in reduction the flavor and the antimutagenicity of this vegetable. Methods: Through hearing survey, we explored reasons for the successful nationwide distribution of heirloom vegetable, mizuna. Through chemical analysis, the fragrant ingredients in mizuna, their antimutagenicity and the changes in their amount for one year were determined. Results and discussion: The primary factor for commencing the distribution of mizuna includes the new idea of using young less-branched form of mizuna as salad ingredient, which has been recognized by most who were involved in promoting the distribution of mizuna among farmers, distributors, and employees of agricultural extension section at Kyoto Prefecture office. The secondary factor is the fact that the primary factor coincides on a time axis with other two factors: the occurrence of the boom of Kyoto’s heirloom vegetables and the Vegetable Management Stabilization Project found as a measure of Kyoto Prefecture. We determined three fragrant compounds in mizuna, 3-butenyl isothiocyanate, 3-phenylpropionitrile, and phenylethyl isothiocyanate, of which their antimutagenic effects were also identified. Those amounts were highest at the best harvest season called ‘Syun’ in the past because of the cold temperature of Japanese winter in traditional open-field cultivation. Conclusion: It implied that the successful nationwide distribution of mizuna resulted from the administrative measures based on the paradigm shift in the new use of mizuna for salad due to increase in demand of the vegetable in contemporary dishes. The traditional cultivation of mizuna might be suitable if wishing the flavor and antimutagenicity at the best harvest season ‘Syun’.