研究者詳細 - 玉川　雅章

論文 - 玉川　雅章

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Fundamental Investigation on Contactless and Continuous Blood Pressure Measurement by Impinging Jet Flow and Imaging Photoplethysmography 査読有り国際誌

Ayumu Yamamoto, Kota Taoka, Koh Hirakawa, Yoshiki Yanagita, Yuko Miyamura, Yohji Yamamoto, Takeshi Tachibana, Tetsuya Kimura and Masaaki Tamagawa

ICIC Express Letters(Innovative Computing, Information and Control) ( ICIC International ) 19 ( 5 ) 527 - 534 2025年05月

Improvising the Tesla Micro-Turbine: Experimental and Performance Analysis 査読有り国際誌

Muhamad Nazri, M.N.I.; Basri, A.A.; Abdullah, M.N.; Mustapha, F.; Bajuri, F.; Basri, E.I.; Tamagawa, M.

Journal of Advanced Research in Fluid Mechanics and Thermal Sciences ( Semarak Ilmu Publishing ) 129 ( 1 ) 58 - 68 2025年05月

Generation and control of underwater microshock waves and microbubbles by a femtosecond pulse laser 査読有り国際誌

Ayumu Yamamoto, Masaaki Tamagawa

Shock Waves ( Springer Nature ) 35 ( 3 ) Online, 9 pages 2025年04月

Newly proposed Method of Pressure Measurement by Tracking Particles for Underwater Micro Shock Waves 査読有り国際誌

Ayumu Yamamoto, Masaaki Tamagawa

International Journal of Innovative Computing, Information & Control (IJICIC) ( ICIC International ) 21 ( 1 ) 53 - 68 2025年02月

EVALUATING VIRUS INFECTION RISK BY INDOOR VENTILATION BASED ON COMPUTATIONAL FLUID DYNAMICS WITH CONCENTRATION MODEL 査読有り国際誌

Feng K., Yanagita Y., Miyamura Y., Basri A.A., Zuber M., Rohani S., Ahmad K.A., Tamagawa M.

ICIC Express Letters ( ICIC International 学会 ) 18 ( 12 ) 1283 - 1289 2024年12月

担当区分：責任著者記述言語：英語掲載種別：研究論文（学術雑誌）

While reported COVID-19 outbreaks decline worldwide, the threat of the airborne virus and indoor transmission lingers, particularly where public mask mandates have ceased. This study presents a risk assessment methodology using the ‘quanta’ concentration model and computational fluid dynamics (CFD) calculations. The research centers on the influence of ventilation strategies on mitigating virus transmission indoors. Results show that ventilation systems and habits such as opening windows and doors can significantly decrease aerosol concentrations, thus reducing infection risks. The application of the ‘quanta’ concentration model in conjunction with enhanced ventilation strategies provides a clear depiction of transmission risk among primary patients and other individuals. Hence, the importance of effective ventilation in managing the spread of airborne viruses indoors is underscored.

DOI： 10.24507/icicel.18.12.1283

Scopus

CiNii Research

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Thermal Energy Storage Potential of Banana Stem and Peel: Comparing Heat Conductivity at Room Temperature Post-Oven Drying 査読有り国際誌

Nazarudin A.I., Basri A.A., Basri E.I., Ahmad K.A., Haji Hameed Sultan M.T., Tamagawa M.

Journal of Advanced Research Design 123 ( 1 ) 23 - 33 2024年12月

記述言語：英語掲載種別：研究論文（学術雑誌）

Bananas, a globally consumed staple, generate substantial agricultural waste, particularly peels and pseudostems, which account for over 60 % of the biomass. This waste presents an opportunity for value-added applications, especially in fire safety and thermal-resistant materials. In this study, dried banana pseudostems and peels were analysed for their thermal properties using Newton’s Law of Cooling. Key findings revealed that banana pseudostem outperformed the peel in thermal resistance, attributed to its higher lignin and cellulose content, which enhance insulation. These properties suggest that banana by-products hold significant potential for sustainable, thermally resistant materials, addressing fire safety challenges in regions like Malaysia. This research underscores the dual environmental and functional benefits of repurposing banana waste, aligning with sustainable development goals and promoting eco-friendly innovations.

DOI： 10.37934/ard.123.1.2333

Scopus

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Observation of Deformation Process of Elastic Tubes for Pulsatile Flows by Impinging Jet Flows and Its Application to Novel Measurement Method of Blood Pressure 査読有り国際誌

Ayumu Yamamoto, Yoshiki Yanagita, Yuko Miyamura, Takeshi Tachibana, Yohji Yamamoto, Tetsuya Kimura, Masaaki Tamagawa

Journal of Advanced Research in Fluid Mechanics and Thermal Sciences 119 ( 2 ) 149 - 159 2024年07月

Evaluation of Thrombus Formation around a Peripheral Intravenous Catheter for Infants by Computational Fluid Dynamics with Consideration of Concentration 査読有り国際誌

Miyamura Yuko, Komatani Kairi, Tamagawa Masaaki

ICIC Express Letters, Part B: Applications ( ICIC International ) 15 ( 07 ) 659 - 667 2024年07月

Impact of obstruction size on ureter dynamics: A computational investigation 査読有り国際誌

Keni L.G., Shenoy B S., K N C., Hegde P., K P., Tamagawa M., Shetty D.D., Futane M., Zuber M.

Results in Engineering 22 2024年06月

記述言語：英語掲載種別：研究論文（学術雑誌）

Kidney stones, known medically as nephrolithiasis, present a significant health concern globally, particularly in regions such as India and the Middle East. Despite extensive research, the complexity of ureteral obstruction due to kidney stones remains a challenge in urology. This study addresses this gap by analysing the effects of obstruction in a three-dimensional model of the ureter with a constant diameter, simulating various percentages of blockage. Through computational analysis, the pressure and velocity effects on the ureter wall are explored, providing insights into the dynamics of obstructed ureters. Building upon previous research, this study contributes to a deeper understanding of the factors influencing flow patterns and pressure variations within the urinary tract. Additionally, findings from this study may lead to advancements in non-invasive assessment methods for diagnosing and treating ureteral obstruction caused by kidney stones. Furthermore, insights gained from this research could potentially inform clinical decision-making, leading to improved management strategies and better outcomes for patients affected by this debilitating condition. The novelty of this work lies in its comprehensive analysis of the effects of obstruction on the ureteral wall, offering valuable implications for urological practice and patient care.

DOI： 10.1016/j.rineng.2024.102217

Scopus

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フェムト秒レーザ誘起水中マイクロ衝撃波の可視化 -微小なスケールでの高速現象の可視化- 招待有り査読有り

山本歩夢，玉川雅章

可視化情報 ( 可視化情報学会 ) 44 ( 170 ) 8 - 12 2024年06月

Analyzing Single Peristaltic Wave Behavior in Ureter with Variable Diameters: A Ureterdynamic Study 査読有り国際誌

Keni L.G., Satish S.B., Chethan K.N., Hegde P., Prakashini K., Tamagawa M., Zuber M.

CFD Letters 16 ( 4 ) 54 - 68 2024年05月

記述言語：英語掲載種別：研究論文（学術雑誌）

Ureters are muscular tubes that transport urine from the kidney to the bladder. The peristalsis wave is responsible for carrying urine to the bladder. With the regular appearance of peristalsis, areas with anatomic narrowing junctions are crucial for ureteral diseases. A three-dimensional flow analysis is performed for different time steps to understand the effect of the urine bolus formation and the reflux phenomenon on variable diameter ureters. For the constant and variable diameter ureter, the pressure is obtained behind and in front of the propagating bolus respectively. The peristalsis wave creates the high-velocity of a jet in the neck region of the ureter. The contraction produces the trapping of the bolus leading to adverse flow in the contraction region. By virtue tapering, the high-pressure gradient builds up, leading to high wall shear in the ureter. The main goal is to determine the pressure, velocity, gradient pressure, and shear force on the ureter wall during peristaltic motion. These parameters are very important for clinicians to understand its effect in the unobstructed variable diameter ureter. This article may help to build a medical device for engineers. The physical significance of this information lies in its profound insights into the biomechanics and functionality of the ureters, which are essential components of the human urinary system.

DOI： 10.37934/cfdl.16.4.5468

Scopus

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CFD investigation of multiple peristaltic waves in a 3D unobstructed ureter 査読有り国際誌

Keni L.G., Satish Shenoy B., Chethan K.N., Hegde P., Prakashini K., Tamagawa M., Zuber M.

Biomedical Physics and Engineering Express 10 ( 2 ) 2024年03月

記述言語：英語掲載種別：研究論文（学術雑誌）

Ureters are essential components of the urinary system and play a crucial role in the transportation of urine from the kidneys to the bladder. In the current study, a three-dimensional ureter is modelled. A series of peristaltic waves are made to travel on the ureter wall to analyse and measure parameter effects such as pressure, velocity, gradient pressure, and wall shear at different time steps. The flow dynamics in the ureters are thoroughly analysed using the commercially available ANSYS-CFX software. The maximum pressure is found in the triple wave at the ureteropelvic junction and maximum velocity is observed in the single and double wave motion due to the contraction produced by the peristalsis motion. The pressure gradient is maximum at the inlet of the ureter during the single bolus motion. The contraction produces a high jet of velocity due to neck formation and also helps in urine trapping in the form of a bolus, which leads to the formation of reverse flow. Due to the reduction in area, shear stress builds on the ureter wall. The high shear stress may rupture the junctions in the ureter.

DOI： 10.1088/2057-1976/ad1f02

Scopus

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Effect of vascular geometry on haemodynamic changes in a carotid artery bifurcation using numerical simulation 査読有り国際誌

Abhilash H.N., Yanagita Y., Pai R., Zuber M., Tamagawa M., K P., Kamath S G., R P., Barboza A.B.V., Rao V.R.K., Khader S.M.A.

Clinical Neurology and Neurosurgery 237 2024年02月

記述言語：英語掲載種別：研究論文（学術雑誌）

Objectives: The geometry of carotid bifurcation is a crucial contributing factor to the localization of atherosclerotic lesions. Currently, studies on carotid bifurcation geometry are limited to the region near to bifurcation. This study aimed to determine the influence of carotid bifurcation geometry on the blood flow using numerical simulations considering magnitude of haemodynamic parameters in the extended regions of carotid artery. Methods: In the present study, haemodynamic analysis is carried out using the non-Newtonian viscosity model for patient-specific geometries consisting of both Left and Right carotid arteries. A 3D patient-specific geometric model is generated using MIMICS, and a numerical model is created using ANSYS. Results: The results obtained from patient-specific cases are compared. The influence of geometric features such as lumen diameter, bifurcation angle, and tortuosity on the haemodynamics parameters such as velocity, WSS, pressure, Oscillatory Shear Index (OSI), and Time-Averaged Wall Shear Stress (TAWSS) are compared. Conclusion: The results demonstrate significant changes in the flow regime due to the geometric shape of the carotid artery. It is observed that the lower value of TAWSS occurs near the bifurcation region and carotid bulb region. In addition, the higher value of the (OSI) is observed in the Internal Carotid Artery (ICA) and the tortuous carotid artery region. However, it is also observed that apart from the bifurcation angle, other factors, such as tortuosity and area ratio, play a significant role in the flow dynamics of the carotid artery.

DOI： 10.1016/j.clineuro.2024.108153

Scopus

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Recent Development of Transcatheter Aortic Valve Implantation (TAVI): Reality in Malaysia 査読有り国際誌

Basri A.A., Basri E.I., Zuber M., Aziz A.F.A., Zakaria M.S., Ali R.M., Tamagawa M., Ahmad K.A.

Lecture Notes in Bioengineering 79 - 92 2024年01月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

Cardiovascular disease (CVD) is the major cause of death in many countries around the world especially in Malaysia. One of the most common CVD is heart valve diseases specifically aortic stenosis (AS) disease that occurs in elderly heart disease patients. Surgical aortic valve replacement (SAVR) is known as one of the most popular techniques for replacing new heart valves. For the past 15 years, transcatheter aortic valve implantation (TAVI) has become the current emerging solution and a good alternative to surgery for patients at very high or prohibitive surgical risk. TAVI has received great attention from broad research studies and clinical experiences due to the lower operative risk with shorter time of recovery compared to surgical aortic valve (SAV) replacement. This paper will review two TAVI devices (Edwards SAPIEN Valve TM and Medtronic CoreValve) that have seen wide application over the past 10 years and discuss the Malaysian practices on TAVI in accessing relevant information with evidence-based recommendations from clinical updates. Ultimately, these discussions will pave the way for new research areas for the improvement of future TAVI technology.

DOI： 10.1007/978-981-97-1920-4_9

Scopus

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フェムト秒レーザ誘起水中マイクロ衝撃波の可視化―微小なスケールでの高速現象の可視化― 査読有り

玉川雅章

可視化情報 44(170) 2024年01月

Effects of Muscle Strength Decline Associated with Older Adults on Effectiveness of Self-protective Measure on Falls using OpenSim 査読有り国際誌

Xuxiang Jiang, Masaaki Tamagawa

Journal of Advanced Research in Applied Mechanics 108 ( 1 ) 124 - 132 2023年09月

担当区分：責任著者記述言語：英語掲載種別：研究論文（学術雑誌）

Falling down is a common and unintentional phenomenon, and the caused body injury may lead to loss of body function or even death. It is estimated that one out of every three older adult individual report a fall at least once every year of which 20% have serious consequence. To predict injury accurately and have better-targeted treatment after falling down, it is necessary to study the damage caused by falling down. To obtain reliable results similar to those of previous high-cost dummy experiments, more effective falling simulation methods should be developed. In this study, by using the biomechanical analysis software OpenSim (open-source software) with the proposed multi-body models associated with older adults’ declined muscle properties, we obtained the kinematic characteristics under different falling down situations for injury evaluation. Finally, the head peak acceleration under several falling down situations are served as the index to evaluate the injury and to obtain this influence of muscle strength decline. Regardless of aging, more positive self-protective can greatly help release the impact. And the declined muscle strength of older adults will higher the risk of fall injury under specific falling down posture.

DOI： 10.37934/aram.108.1.124132

Scopus

その他リンク： https://semarakilmu.com.my/journals/index.php/appl_mech/article/view/3779

Experimental and Theoretical Study of Propulsion Mechanism with Neutrophil Rotation by using Concentration Marangoni Effect 査読有り国際誌

Obana Rintaro, Masaaki Tamagawa

Journal of Advanced Research in Fluid Mechanics and Thermal Sciences 108 ( 1 ) 114 - 125 2023年09月

担当区分：責任著者記述言語：英語掲載種別：研究論文（学術雑誌）

In the immunological systems, neutrophil propulsion is considered to be driven by the concentration gradient of cytokines. However, the mechanism of propulsion has not been elucidated yet in previous research. In our investigations, assuming that neutrophil moves by the concentration Marangoni effect, the concentration gradient of cytokine on the neutrophil membrane was experimentally examined. The result showed that the cytokine concentration gradient on neutrophil membranes periodically changed. It indicates the possibility that neutrophils move while rotating under the cytokine concentration gradient. However, the neutrophil's rotation is difficult to be observed because experimental verification is limited due to the accuracy and sensitivity of the present measurement system. Therefore, no evidence has been found yet for a relationship between neutrophil velocity and rotation. In this study, assuming that the neutrophil is rotating, this relationship is investigated by theoretical and experimental approaches. As for the theoretical approach, the neutrophil velocity by the concentration Marangoni effect is calculated by using a special mathematical model. From this result, it was found that the velocity is high when the period is short. As for the experimental approach, to obtain the velocity and the concentration gradient on the membrane, neutrophil velocity and distribution of cytokine concentrations are observed with microscopy. In the experiment, the period of rotation was obtained from the time history of the concentration gradient by FFT (Fast Fourie Transform). From the results, the following three findings were obtained. At first, neutrophil velocity is not constant and vibrates. Second, when the rotation period is short, the velocity is fast. Third, when the distance between the neutrophil and the wall is close, the rotation period is longer and the velocity is lower. From these findings, it was concluded that neutrophil rotation is an important role in neutrophil’s propulsion mechanism.

DOI： 10.37934/arfmts.108.1.114125

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CFD Analysis of Indoor Ventilation for Airborne Virus Infection 査読有り国際誌

Feng K., Yanagita Y., Miyamura Y., Basri A.A., Zuber M., Rohani S., Ahmad K.A., Tamagawa M.

Journal of Advanced Research in Numerical Heat Transfer 14 ( 1 ) 1 - 16 2023年09月

担当区分：責任著者記述言語：英語掲載種別：研究論文（学術雑誌）

Indoor airflow patterns and air residence times significantly influence the spread of airborne infectious viruses, such as COVID-19. These factors can be quantified using computational fluid dynamics (CFD). In this study, CFD was utilized to assess the indoor airflow patterns and calculate air residence times in a typical restroom with high personnel flow and low ventilation efficiency. The results identified regions with high air residence times, indicating potential risk areas for airborne virus retention. Furthermore, the effects of different ventilation strategies on these high-risk areas were analyzed. Despite meeting air change standards, certain regions were found to potentially pose a higher risk due to prolonged air residence times. Based on these findings, recommendations for improving ventilation systems to reduce the risk of airborne virus infection were proposed. This study highlights the necessity of a more nuanced approach to indoor air assessment than simply calculating air changes per hour. It was concluded that (1) different ventilation strategies can greatly affect the air residence time in the room and (2) the variance of air residence time in the air circulation area are large in some locations, even with simple ventilation adjustments.

DOI： 10.37934/arnht.14.1.116

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High field-effect mobility in oriented thin films of D-A type semiconducting polymers by engineering stable interfacial system 査読有り国際誌

Sharma S., Vats A.K., Tang L., Kaishan F., Toyoda J., Nagamatsu S., Ando Y., Tamagawa M., Tanaka H., Pandey M., Pandey S.S.

Chemical Engineering Journal 469 2023年08月

記述言語：英語掲載種別：研究論文（学術雑誌）

Conjugated polymers (CPs) have emerged as excellent organic semiconducting materials for flexible electronic applications. CPs exhibit a notably fast carrier transport along their main π-conjugated backbone followed by inter-chain hopping compelling the need to form large and ordered domains in thin films. Therefore, the formation of larger domains, along with their orientation, is critical in controlling the electrical properties of CP-based organic electronic devices. However, controlling the molecular ordering along with the formation of large aggregates is a challenge. In this work, the unidirectional floating film transfer method (UFTM) has been utilized to prepare oriented thin films of CPs, which is a highly facile, cost-effective and material utilization efficient technique. We have demonstrated that extent and direction of molecular orientation in the fabricated thin films can be tuned along with the higher degree of aggregation. The rheological aspects, especially viscosity, play a significant role in determining molecular ordering along with the formation of these large aggregates. Active control of viscosity to achieve a stable interfacial viscous system is paramount to achieving this, resulting in a very high mobility of 12.4 cm2V−1s−1.

DOI： 10.1016/j.cej.2023.143932

Scopus

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Variation of Shear Stresses and Flow Dynamics in Stented Patient Specific Carotid Bifurcation Model using Numerical Investigation 査読有り国際誌

Almeida N.R., Abdul Khader S.M., Ningappa Abhilash H., Yamaguchi Y., Ballambat R.P., Zuber M., Prakashini K., Ganesh Kamath S., Tamagawa M., Padmakumar R., Rao V.R.K., Barboza A.B.V.

CFD Letters 15 ( 6 ) 98 - 114 2023年06月

記述言語：英語掲載種別：研究論文（学術雑誌）

The carotid artery is a clinically important site in the human circulatory system as the consequences of its disease results in adverse outcomes like ischemic strokes, or death for too prolonged ischemia. Understanding the hemodynamics of this artery and its bifurcation are important. A method of treating the stenosis of this artery is Carotid Angioplasty and Stenting (CAS). This procedure results in a heavily modified hemodynamics or state of flow. To understand and predict this flow field modification Computational Fluid Dynamics (CFD) is an important computational tool. Further, the presence of a stent would affect hemodynamics. The aim of this work is to study these effects in patient-specific cases. The reconstructed patient-specific models will form the basis of the construction of the post-stenting carotid bifurcation models. A transient analysis was carried out to estimate the time-varying parameters in the fluid domains over a cardiac cycle as well as to gauge time average values over a cardiac cycle. Results are obtained for hemodynamic parameters, like wall shear stress, velocity, pressure, vorticity, and helicity, in both the prepared stenosed and stented geometries. It is seen that the stenting procedure leads to the renewal of the CCA to ICA flow path. But simultaneously the region in which the stent is present becomes a region of low TAWSS and contains areas of high OSI. These areas of low TAWSS and high OSI within the stented portions of the carotid bifurcations are indications for regions of possible restenosis. Therefore, the investigation demonstrates the likely region for future plaque growth. Further, the effects of widening of the lumen are also noted in comparison to the pre-stent cases.

DOI： 10.37934/cfdl.15.6.98114

Scopus

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