Development and validation of fuel stub motion model for the disrupted core of a sodium-cooled fast reactor

Kenichi Kawada,Tohru Suzuki 한국원자력학회 2021 Nuclear Engineering and Technology Vol.53 No.12

To improve the capability of the SAS4A code, which simulates the initiating phase of core disruptiveaccidents for MOX-fueled Sodium-cooled Fast Reactors (SFRs), the authors have investigated in detail thephysical phenomena under unprotected loss-of-flow (ULOF) conditions in a previous paper (Kawada andSuzuki, 2020) [1]. As the conclusion of the last article, fuel stub motion, in which the residual fuel pelletswould move toward the core central region after fuel pin disruption, was identified as one of the keyphenomena to be appropriately simulated for the initiating phase of ULOF. In the present paper, based on the analysis of the experimental data, the behaviors related to the stubmotion were evaluated and quantified by the author from scratch. A simple model describing fuel stubmotion, which was not modeled in the previous SAS4A code, was newly proposed. The applicability ofthe proposed model was validated through a series of analyses for the CABRI experiments, by which thestub motion would be represented with reasonable conservativeness for the reactivity evaluation ofdisrupted core

Fat Cell Formation and Obesity-Related Diseases

Kawada, Teruo The Korean Society of Food Science and Nutrition 2003 Preventive Nutrition and Food Science Vol.8 No.1

Animals possess a highly sophisticated mechanism of storing energy in adipose tissue inside their bodies. However, in humans it has been clarified that adipocyte (fat cell), which composes the body fat (adipose) tissues, development and the extent of subsequent fat accumulation are closely associated with the occurrence and advancement of various common diseases (e.g., type-2 diabetes, coronary artery disease, and hypertension) resulting from obesity. Recent exciting progress in clinical and biochemical studies of adipocytes has rapidly clarified the functions of adipocytes and adipose tissue. Interesting findings are the function of white adipocytes as "secreting cells" and the molecular mechanism undelying adipocyte differentiation at the transcriptional level in relation to nuclear receptors. Consequently, the adipose tissue is being targeted for the prevention or treatment of many common diseases. In this review, I will focus on recent information on characteristics of adipocytes and the relationship between obesity and common obesity-related diseases. diseases.

KOREAN NAJEONCHILGI OF THE GORYEO AND EARLY JOSEON PERIODS

( Kawada Sadamu ) 국립중앙박물관 2008 Journal of Korean Art and Archaeology (JKAA) Vol.2 No.0

According to Xuanhe fengshi Gaoli tujing (宣和奉使高麗圖經: An Illustrated Account of an Embassy to Goryeo in the Xuanhe Era) by Xu Jing from the Song dynasty in 1123, the najeonchilgi or inlaid lacquer artifacts of Goryeo made by craftsmen in the capital city of Gaeseong were “extremely refined and to be treasured.” Although the heyday of najeon or inlaid mother-of-pearl technique was in the Tang dynasty and the finely-crafted mother-of-pearl products from China were well recognized by Japanese envoys to that country, Chinese motherof- pearl production fell into a gradual decline and this trend accelerated into the Song era. However, by the early twelfth century, when Xu Jing wrote the Xuanhe fengshi Gaoli tujing, Korean najeon had developed so far as to surpass that of China, where the technique had originated. Time was needed to achieve such a high level of skill. Perhaps the resplendent mother-of-pearl technique of the Tang dynasty, which had been received in Korea in the era of Unified Silla, had sown seed, and Korean uniqueness was gradually infused into the original. It passed through a long period of gestation during late Silla and the early Goryeo period, and when Goryeo aristocratic culture came to a peak in the eleventh and twelfth centuries, Korean najeon flourished as never before. This paper analyzes the chronology of the historical era by dividing sixteen najeon-decorated artifacts into groups A-D based on the classification proposed by Okada Jo (岡田讓).1 The characteristics of the decorative techniques seen in Goryeo najeon products include: using multiple najeon fragments to form each unit of the pattern; the use of twisted metal wires such as silver, copper, and brass in combination with najeon; and using back-painted tortoiseshell in combination with najeon for an effect of translucent brilliance. In conclusion, the chronology of the Goryeo najeon artifacts remains extremely uncertain because the number of pieces imported to Japan and of artifacts in western museums acquired via Japan is very limited. Hopefully, research findings will come out of Korea by discovering new artifacts backed up by data, comparing them with the najeon products of the Joseon dynasty, finding their relationship with other artifacts, and by the excavation of examples from the tombs of the Goryeo dynasty whose dates can be known beyond doubt.

Recent State of Monitoring Techniques for environmental Radiation and Radioactivity in Japan

Kawada, Y. 대한방사선 방어학회 1989 방사선방어학회지 Vol.14 No.1

Utility of Noncontrast Magnetic Resonance Angiography for Aneurysm Follow-Up and Detection of Endoleaks after Endovascular Aortic Repair

Kawada Hiroshi,Goshima Satoshi,Sakurai Kota,Noda Yoshifumi,Kajita Kimihiro,Tanahashi Yukichi,Kawai Nobuyuki,Ishida Narihiro,Shimabukuro Katsuya,Doi Kiyoshi,Matsuo Masayuki 대한영상의학회 2021 Korean Journal of Radiology Vol.22 No.4

Objective: To assess the noncontrast two-dimensional single-shot balanced turbo-field-echo magnetic resonance angiography (b-TFE MRA) features of the abdominal aortic aneurysm (AAA) status following endovascular aneurysm repair (EVAR) and evaluate to detect endoleaks (ELs). Materials and Methods: We examined four aortic stent-grafts in a phantom study to assess the degree of metallic artifacts. We enrolled 46 EVAR-treated patients with AAA and/or common iliac artery aneurysm who underwent both computed tomography angiography (CTA) and b-TFE MRA after EVAR. Vascular measurements on CTA and b-TFE MRA were compared, and signal intensity ratios (SIRs) of the aneurysmal sac were correlated with the size changes in the AAA after EVAR (AAA prognoses). Furthermore, we examined six feasible b-TFE MRA features for the assessment of ELs. Results: There were robust intermodality (r = 0.92–0.99) correlations and interobserver (intraclass correlation coefficient = 0.97–0.99) agreement. No significant differences were noted between SIRs and aneurysm prognoses. Moreover, “mottled high-intensity” and “creeping high-intensity with the low-band rim” were recognized as significant imaging findings suspicious for the presence of ELs (p < 0.001), whereas “no signal black spot” and “layered high-intensity area” were determined as significant for the absence of ELs (p < 0.03). Based on the two positive features, sensitivity, specificity, and accuracy for the detection of ELs were 77.3%, 91.7%, and 84.8%, respectively. Furthermore, the k values (0.40–0.88) displayed moderate-toalmost perfect agreement. Conclusion: Noncontrast MRA could be a promising imaging modality for ascertaining patient follow-up after EVAR.

Floristic Composition, Grazing Effects and Above-ground Plant Biomass in the Hulunbeier Grasslands of Inner Mongolia, China

Kawada, Kiyokazu,Mayu Kurosu,Yunxiang Cheng,Tsagaanbandi Tsendeekhuu,Wuyunna,Toru Nakamura,Ichiroku Hayashi 한국생태학회 2008 Journal of Ecology and Environment Vol.31 No.4

In order to assess the effect of grazing on grasslands using floristic composition, we studied the floristic composition and plant biomass of steppe vegetation in Hulunbeier, Inner Mongolia. The dominant species of the grasslands were Stipa krylovii, Stipa grandis and Leymus chinensis. Floristic composition changed according to grazing pressure, being light, heavy and moderate. Under heavy grazing conditions, the importance value of P. acaulis, C. korshinskyi and Cleistogenes squarrosa increased in the plant community. These species were indicators of heavily grazed stand. Plant biomass of the stands ranged within 11.6 g m-2 and 63.5 g m-² and 69.5 g m-² and 166.2 g m-² to the west and east of Lake Hulun, respectively. These values are equivalent to ca. 450~1,000 kg of atmospheric carbon per hector, which is retained within the stand during the summer season. In order to assess the effect of grazing on grasslands using floristic composition, we studied the floristic composition and plant biomass of steppe vegetation in Hulunbeier, Inner Mongolia. The dominant species of the grasslands were Stipa krylovii, Stipa grandis and Leymus chinensis. Floristic composition changed according to grazing pressure, being light, heavy and moderate. Under heavy grazing conditions, the importance value of P. acaulis, C. korshinskyi and Cleistogenes squarrosa increased in the plant community. These species were indicators of heavily grazed stand. Plant biomass of the stands ranged within 11.6 g m-2 and 63.5 g m-² and 69.5 g m-² and 166.2 g m-² to the west and east of Lake Hulun, respectively. These values are equivalent to ca. 450~1,000 kg of atmospheric carbon per hector, which is retained within the stand during the summer season.

NOTE - Determination of UVA Protection Factor with SPEX SkinSkan

Kawada, Akira,Kameyam, Hiroko,Sangen, Yoshiko,Aragane, Yoshinori,Tezuka, Tadashi,Hamagami, Ikuko Korean Society of Photoscience 2003 Journal of Photosciences Vol.10 No.2

SPEX SkinSkan is a newly developed spectrofluorometer that can calculate transmission of UVA on the surface of human skin as a non-invasive method. We have investigated UVA protection factors of Japanese over-the-counter sunscreens using SPEX SkinSkan. This non-invasive method is useful to know UVA protection of sunscreens in vivo.

Letter to the editor: Coffee consumption and bone health: A risk assessment

Tomoyuki Kawada 대한골다공증학회 2020 Osteoporosis and Sarcopenia Vol.6 No.1

Multiphase Contrast-Enhanced Magnetic Resonance Imaging Features of Bacillus Calmette-Guérin-Induced Granulomatous Prostatitis in Five Patients

Hiroshi Kawada,Masayuki Kanematsu,Satoshi Goshima,Hiroshi Kondo,Haruo Watanabe,Yoshifumi Noda,Yukichi Tanahashi,Nobuyuki Kawai,Hiroaki Hoshi 대한영상의학회 2015 Korean Journal of Radiology Vol.16 No.2

To evaluate the multiphase contrast-enhanced magnetic resonance (MR) imaging features of Bacillus Calmette-Guérin (BCG)-induced granulomatous prostatitis (GP). Magnetic resonance images obtained from five patients with histopathologically proven BCGinduced GP were retrospectively analyzed for tumor location, size, signal intensity on T2-weighted images (T2WI) and diffusion-weighted images (DWI), apparent diffusion coefficient (ADC) value, and appearance on gadolinium-enhanced multiphase images. MR imaging findings were compared with histopathological findings. Bacillus Calmette-Guérin-induced GP (size range, 9–40 mm; mean, 21.2 mm) were identified in the peripheral zone in all patients. The T2WI showed lower signal intensity compared with the normal peripheral zone. The DWIs demonstrated high signal intensity and low ADC values (range, 0.44–0.68 x 10-3 mm2/sec; mean, 0.56 x 10-3 mm2/sec), which corresponded to GP. Gadolinium-enhanced multiphase MR imaging performed in five patients showed early and prolonged ring enhancement in all cases of GP. Granulomatous tissues with central caseation necrosis were identified histologically, which corresponded to ring enhancement and a central low intensity area on gadolinium-enhanced MR imaging. The findings on T2WI, DWI, and gadolinium-enhanced images became gradually obscured with time. Bacillus Calmette-Guérin-induced GP demonstrates early and prolonged ring enhancement on gadoliniumenhanced MR imaging which might be a key finding to differentiate it from prostate cancer.

Prevalence and Correlates of Disordered Sleep in Southeast Asian Indians with Type 2 Diabetes (Diabetes Metab J 2012;36:70-6)

Tomoyuki Kawada 대한당뇨병학회 2012 Diabetes and Metabolism Journal Vol.36 No.4