Experimental and Numerical Investigations on Performances of Darriues-type Hydro Turbine with Inlet Nozzle

Daisuke Matsushita,Kei Tanaka,Satoshi Watanabe,Kusuo Okuma,Akinori Furukawa 한국유체기계학회 2014 International journal of fluid machinery and syste Vol.7 No.4

Low head hydropower is one of realistic renewable energies. The Darrieus-type hydro turbine with an inlet nozzle is available for such low head conditions because of its simple structure with easy maintenance. Experimental and numerical studies are carried out in order to examine the effects of gap distances between the runner pitch circle and two edges of inlet nozzle on turbine performances. By selecting narrower gaps of left and right edges, the performance could be improved. From the results of two dimensional numerical simulations, the relation between the performance and flow behaviors around the Darrieus blade are discussed to obtain the guideline of appropriate inlet nozzle design.

Experimental and Numerical Investigations on Performances of Darriues-type Hydro Turbine with Inlet Nozzle

Matsushita, Daisuke,Tanaka, Kei,Watanabe, Satoshi,OKuma, Kusuo,Furukawa, Akinori Korean Society for Fluid machinery 2014 International journal of fluid machinery and syste Vol.7 No.4

Low head hydropower is one of realistic renewable energies. The Darrieus-type hydro turbine with an inlet nozzle is available for such low head conditions because of its simple structure with easy maintenance. Experimental and numerical studies are carried out in order to examine the effects of gap distances between the runner pitch circle and two edges of inlet nozzle on turbine performances. By selecting narrower gaps of left and right edges, the performance could be improved. From the results of two dimensional numerical simulations, the relation between the performance and flow behaviors around the Darrieus blade are discussed to obtain the guideline of appropriate inlet nozzle design.

Firmicutes in Gut Microbiota Correlate with Blood Testosterone Levels in Elderly Men

Matsushita Makoto,Fujita Kazutoshi,Motooka Daisuke,Hatano Koji,Hata Junya,Nishimoto Mitsuhisa,Banno Eri,Takezawa Kentaro,Fukuhara Shinichiro,Kiuchi Hiroshi,Pan Yue,Takao Toshifumi,Tsujimura Akira,Yach 대한남성과학회 2022 The World Journal of Men's Health Vol.40 No.3

Purpose: In males, testosterone levels have been implicated in various diseases. Recently, the influence of gut microbialderived compounds on host metabolism has become evident, and it has been suggested that some gut bacteria may be involved in testosterone metabolism. In the present study, we examined the relationship between testosterone levels and gut microbiota in elderly Japanese men. Materials and Methods: We collected samples from Japanese male subjects suspected of having prostate cancer and underwent prostate biopsies and excluded patients with positive biopsies to avoid the effect of prostate cancer on the gut microbiota. In total, 54 Japanese males with negative biopsy results were included in our study. The gut microbiota was analyzed by 16S rRNA gene sequencing of bacterial DNA extracted from rectal swabs. Gut microbiota compositions were compared between the two groups according to the level of serum testosterone (above or below 3.5 ng /mL). Results: The median age of the cohort was 71 years, and the quartile range was 67 to 73 years. We observed no significant difference in alpha or beta diversity, but some bacteria belonging to the phylum Firmicutes (Clostridiales, Turicibacter, and Gemella) were increased in the high testosterone group. Serum testosterone levels positively correlated with the relative amount of Firmicutes (rS=0.3323, p=0.0141), and the amount of Firmicutes affected serum testosterone levels independent of host factors (age, body mass index, triglyceride, and total cholesterol; β=0.770, p=0.0396). Conclusions: Some intestinal bacteria belonging to the phylum Firmicutes were associated with testosterone levels in elderly males. Therefore, the gut microbiota could affect testosterone metabolism in elderly males.

Differences in preoperative planning for high-tibial osteotomy between the standing and supine positions

( Takehiko Matsushita ),( Shu Watanabe ),( Daisuke Araki ),( Kanto Nagai ),( Yuichi Hoshino ),( Noriyuki Kanzaki ),( Tomoyuki Matsumoto ),( Takahiro Niikura ),( Ryosuke Kuroda ) 대한슬관절학회 2021 대한슬관절학회지 Vol.33 No.-

Introduction: Previous studies have reported that alignment changes depend on the patient’s position in orthopedic surgery. However, it has not yet been well examined how the patient’s position affects the preoperative planning in high-tibial osteotomy (HTO). Therefore, the aim of this study was to investigate the effects of the patient’s position on preoperative planning in HTO. Materials and methods: A total of 60 knees in 55 patients who underwent HTO were retrospectively examined. Virtual preoperative planning for medial open-wedge HTO (OWHTO), lateral closed-wedge HTO (CWHTO), and hybrid CWHTO were performed by setting the percentage of the weight-bearing line (%WBL) at 62% as an optimal alignment. The correction angle differences between the supine and standing radiographs were measured. The virtual %WBL (v%WBL) was determined by applying the correction angle obtained from the standing radiograph to the supine radiograph. The %WBL discrepancy (%WBLd) was calculated as v%WBL - 62 (%) to predict the possible correction errors during surgeries. A single regression analysis was performed to examine the correlation between the correction angle difference and %WBLd. Results: The mean correction angle was significantly higher when the preoperative planning was based on standing radiographs than when based on supine radiographs (P < 0.001), and the mean difference was 2.2 ± 1.5°. The difference between the two conditions in the medial opening gaps for OWHTO, lateral wedge sizes (mm) for CWHTO, and hybrid CWHTO were 2.6 ± 2.0, 2.3 ± 1.6, and 1.9 ± 1.4, respectively. The mean v%WBL was 71.2% ± 7.3%, and the mean %WBLd was 10.1% ± 7.4%. A single regression analysis revealed a linear correlation between the correction angle difference and %WBLd (%WBLd = 4.72 × correction angle difference + 0.08). No statistically significant difference in the parameters was found between the supine and standing radiographs postoperatively. Conclusions: We found significant differences in the estimated correction angles between the supine and standing radiographs in the planning for HTO. Therefore, surgeons should carefully consider the difference between supine and standing radiographs and estimate the possible correction error during surgery when planning a HTO.

A Study on Darrieus-type Hydroturbine toward Utilization of Extra-Low Head Natural Flow Streams

Kei Tanaka,Daisuke Matsushita,Kotaro Hirowatari,Kai Shimokawa,Satoshi Watanabe,Akinori Furukawa 한국유체기계학회 2013 International journal of fluid machinery and syste Vol.6 No.3

A two-dimensional Darrieus-type hydroturbine system, installed with a wear for flow streams such as small rivers and waterways, has been developed for hydropower utilization of extra-low head less than 2m. There are several problems such as flow rate change and flowing wastes to be solved for its practical use in natural flow streams. In the present study, at first, a design guideline in the case of overflow or bypass flow is shown by using simple flow model. Next, in order to avoid the unexpected obstacles flowing into the hydroturbine, an installation of waste screening system is examined. It is confirmed that the screen is effective with some amount of bypass flow rate, however the output power is remarkably deteriorated.

EFFECTS OF ASYMMETRIC INLET NOZZLE GEOMETRY ON DUCTED DARRIEUS-TYPE HYDRO TURBINE

Kai SHIMOKAWA,Koutarou HIROWATARI,Daisuke MATSUSHITA,Satoshi WATANABE,Akinori FURUKAWA,Kusuo OKUMA 한국신재생에너지학회 2011 AFORE Vol.2011 No.-

Development of ducted Darrieus turbine for low head hydropower utilization

Akinori Furukawa,Satoshi Watanabe,Daisuke Matsushita,Kusuo Okuma 한국물리학회 2010 Current Applied Physics Vol.10 No.2

It is mentioned in front part of the present paper that how to extract an extra-low head power is one of key-solutions for problems on exhaustion of fossil fuels and greenhouse gas emissions, after explaining the present situation of micro-hydropower utilization in Japan. Since extra-low head sites of rivers are available near urban-sides with high population, where there is a demand for electricity, an appearance of suitable turbine, which has high cost-effectiveness, maximum reliability, easy maintenance and little environmental impact, is required. In rear part of the present paper, a guiding principle of design parameters of a ducted Darrieus-type water turbine for high performance is shown, based on authors’ experimental results. Then the advantage and disadvantage of Darrieus turbine are reviewed and the key problems, which are settled as urgent works in future in order to diffuse the utilization of extra-low head hydropower, are finally suggested.

Analysis of popliteal artery location for high tibial and distal tuberosity osteotomy using contrast-enhanced computed tomography

( Akiyoshi Mori ),( Takehiko Matsushita ),( Nobuaki Miyaji ),( Kanto Nagai ),( Daisuke Araki ),( Noriyuki Kanzaki ),( Tomoyuki Matsumoto ),( Takahiro Niikura ),( Yuichi Hoshino ),( Ryosuke Kuroda ) 대한슬관절학회 2022 대한슬관절학회지 Vol.34 No.-

Background: Our objective was to evaluate the location of popliteal artery (PA) in osteotomy planes during high tibial osteotomy (HTO) and to determine a safer angle for screw drilling to the tibial tuberosity during distal tuberosity osteotomy (DTO). Methods: Twenty knees in 20 patients who underwent contrast-enhanced computed tomography for cardiovascular diseases were examined. Osteotomy planes for open-wedge HTO (OWHTO) and hybrid closed-wedge HTO (hybrid CWHTO) were created using three-dimensional bone models. The distance from the posterior cortex of the tibia to the PA (dPC-PA) in the osteotomy planes was measured in the virtual osteotomy planes. The dangerous point (Point D1) was defined as the point 17.5 mm away from PA, setting the working length of the bone saw as 35 mm. The distance between the most medial point of the tibial cortex (Point M) and Point D1 in OWHTO and the most lateral point (Point L) and Point D1 in hybrid CWHTO were examined (dM-D1 and dL-D1, respectively). The location of Point D1 to the osteotomy line (%D1) was expressed as percentage, setting the start and end of the osteotomy line as 0% and 100%, respectively. To determine the safe angle for screw drilling in DTO, the angle between the line tangential to the medial cortex of the tibia and that passing through the center of the tibial tuberosity and PA were measured. Results: In OWHTO and hybrid CWHTO, the mean dPC-PA was 10.6 mm (6.9-16.5 mm) and 10.2 mm (7.3-15.4 mm), respectively. The mean dM-D1 in OWHTO was 25.9 mm (24.6-27.2 mm) and dL-D1 in hybrid CWHTO was 5.1 mm (2.9-7.4 mm). The mean %D1 was 47.6 ± 3.7% in OWHTO and 9.3 ± 4.1% in hybrid CWHTO, respectively. The minimal angle between the two lines in DTO was 35.2°. Conclusion: PAs could run within 10 mm from the posterior cortex in the osteotomy planes of HTO. Therefore, proper posterior protection is necessary when cutting posterior cortex. An angle of less than 35° against the medial cortex line would be safe for screw fixation to avoid vascular injury in DTO.

Therapeutic Endoscopic Treatment Plus Maintenance Dimethyl Sulfoxide Therapy Prolongs Recurrence-Free Time in Patients With Hunner Type Interstitial Cystitis: A Pilot Study

Atsushi Otsuka,Takahisa Suzuki,Yuto Matsushita,Hiromitsu Watanabe,Keita Tamura,Daisuke Motoyama,Toshiki Ito,Takayuki Sugiyama,Hideaki Miyake 대한배뇨장애요실금학회 2019 International Neurourology Journal Vol.23 No.4

Purpose: To evaluate whether hydrodistention with fulguration of Hunner lesions (HD/FUL) plus maintenance dimethyl sulfoxide (DMSO) therapy prolongs the recurrence-free time in patients with Hunner type interstitial cystitis (IC). Methods: The study enrolled patients with Hunner type IC who required repeat HD/FUL due to recurrence of IC symptoms after the first HD/FUL at our institution. All patients received a second HD/FUL plus maintenance DMSO therapy. The maintenance DMSO therapy was performed every 2 weeks for a total of 8 instillations, and then once every 4 weeks thereafter. The recurrencefree time from HD/FUL to therapeutic failure was estimated using the Kaplan-Meier method. The recurrence-free time between the first HD/FUL and second HD/FUL plus maintenance DMSO therapy was statistically compared using the log-rank test. Results: A total of 21 patients (mean age, 66.3±10.8 years) with Hunner type IC were evaluated. The recurrence-free time for the second HD/FUL plus maintenance DMSO therapy was significantly longer than that for the first HD/FUL (P<0.0001). The median recurrence-free time for the first HD/FUL was 10.1 months, while that for the second HD/FUL plus maintenance DMSO therapy has yet to be reached. The recurrence-free rate for the first HD/FUL was 81.0% at 6 months, 38.1% at 1 year, 9.5% at 2 years, and 4.8% at 3 years. In contrast, the rate for the second HD/FUL plus maintenance DMSO therapy was 100% at 6 months, 94.7% at 1 year, 82.6% at 2 years, and 82.6% at 3 years. There were no significant differences in efficacy between the first and second HD/FUL. Conclusions: HD/FUL plus maintenance DMSO therapy clearly prolongs the recurrence-free time compared with HD/FUL alone in Hunner type IC.

Experimental Study on Adjustment of Inlet Nozzle Section to Flow Rate Variation for Darrieus-type Hydro-Turbine

Satoshi Watanabe,Kai Shimokawa,Akinori Furukawa,Kusuo Okuma,Daisuke Matsushita 한국유체기계학회 2012 International journal of fluid machinery and syste Vol.5 No.1

A two dimensional Darrieus-type turbine has been proposed for the hydropower utilization of extra-low head less than 2m. In a practical use of Darrieus-type hydro-turbine, head and flow rate may be varied temporally and seasonally. Considering that the cost advantage is required for the low head hydro turbine system, the Darrieus turbine should be operated with high efficiency in the wider range of flow rate possibly by using an additional device with simpler mechanism. In the present paper, an adjustment of inlet nozzle section by lowering the inlet nozzle height is proposed to obtain the preferable inlet velocity in low flow rate conditions. Effects of resulting spanwise partial inlet flow are investigated. Finally, an effective modification of inlet nozzle height over flow rate variation is shown.