Gowrava Shenoy Baloor

This research describes the design and development of an attachable electric wheelchair that improves the performance of a traditional wheelchair by incorporating electric propulsion and advanced control mechanisms. The device operates in three independent modes: joystick, application, and voice controlled. We developed the prototype design on SolidWorks and prepared the attachable structure using metal sheets, assembling the parts through gas and electrode welding techniques. The main components include an Arduino Uno microcontroller, an ESP32 wireless module, a BLDC hub motor, and a linear actuator intended for steering. Testing experiments showed that the prototype can support users with different weights, functioning smoothly and reliably. The modular electric wheelchair achieves significantly lower production costs than conventional electric wheelchairs currently available in the market while integrating capabilities absent from the currently available products.

The use of computational fluid dynamics (CFD) to study hemodynamics in arteries offers significant potential for addressing complex flow problems. Due to its enhanced performance hardware and software, CFD has become an important approach for studying hemodynamics in human arteries. This approach is utilized to investigate hemodynamics and forecast risk factors for atherosclerotic lesion development and progression, including circulatory flow, and to analyze local flow fields and flow profiles resulting from geometric changes. This foundational study will aid in analyzing blood flow behavior through the abdominal aorta and the origin and courses of renal arteries, as well as investigating the causes of disorders such as atherosclerosis and hypertension. The current study investigates three idealized abdominal aorta–renal artery junction models under varying blood pressure settings. Materialise software V19 was used to extract the geometry data to create idealized 3D abdominal aorta–renal branching models. Unsteady flow simulations were performed in ANSYS Fluent, utilizing rigid walls and Newtonian and Carreau–Yasuda viscosity conditions. Oscillatory shear index (OSI) and Time-averaged wall shear stress (TAWSS) were measured to enhance understanding of atherosclerotic plaque formation and progression. Also, the effect of geometric change at the bifurcation area was explored, and it was discovered that this location causes considerable vortex forming zones. The evident velocity reduction and backflow development were seen, reducing shear stress. The findings indicate that low TAWSS < 0.4 Pa and OSI > 0.15 areas within the bifurcation region are more susceptible to atherosclerosis development.

Understanding the hemodynamics of the carotid artery is essential for assessing atherosclerotic disease progression and identifying regions vulnerable to plaque formation. Background: Disturbed flow patterns and abnormal shear stresses, particularly near the carotid bifurcation, are known to influence endothelial dysfunction; therefore, this study aims to quantify the impact of patient-specific carotid artery geometry on key hemodynamic parameters associated with atherosclerotic risk. Methods: Four patient-specific carotid artery geometries were reconstructed from medical imaging data, processed using MIMICS, and analyzed using computational fluid dynamics in ANSYS Fluent, with blood modeled as an incompressible non-Newtonian fluid using the Carreau–Yasuda viscosity model under pulsatile flow conditions; velocity streamlines, pressure distribution, time-averaged wall shear stress (TAWSS), and oscillatory shear index (OSI) were evaluated at early systole, peak systole, and peak diastole. Results: The simulations revealed complex flow behaviour, including flow reversal, pressure build-up, and low-shear regions concentrated near the carotid bulb and bifurcation, with TAWSS consistently identifying low-shear zones (<1 Pa) across all geometries and OSI exhibiting pronounced directional oscillations in models with increased curvature and wider bifurcation angles. Conclusions: These findings demonstrate that geometric characteristics such as bifurcation angle, vessel tortuosity, and asymmetry play a critical role in shaping local haemodynamics, underscoring the utility of patient-specific CFD analysis as a diagnostic and predictive tool for atherosclerotic risk assessment and supporting more informed, personalized clinical decision-making.

Аневризма брюшной аорты (АБА) представляет собой прогрессирующее локальное выпячивание брюшной аорты, имеющее высокий риск разрыва и летального исхода. В условиях нормальной физиологии пульсирующий кровоток в брюшной аорте имеет в основном характер ламинарный, несмотря на наличие локальных нарушений, вызванных ответвлениями сосудов и геометрическими вариациями. Наличие аневризмы искажает сосудистую структуру, что приводит к сложной динамике потока, способной стимулировать прогрессирование заболевания. В настоящем исследовании гемодинамика в трехмерных моделях АБА исследовалась с помощью методов вычислительной гидродинамики (CFD). Были рассмотрены идеализированные геометрии аневризмы с четырьмя вариантами экстремального угла наклона проксимальной шейки аорты в предположении ламинарного течения и жесткости артериальной стенки. Моделирование проводилось в течение полного кардиологического цикла для сохранения нестационарности пульсирующего потока. Был произведен анализ распределения скоростей, полей давления, линий тока и пристеночных касательных напряжений (WSS). Результаты показали, что выраженный угол наклона проксимальной шейки аорты вызывает асимметричные паттерны течения, турбулентность и рециркуляцию крови в полости аневризмы, особенно в фазе диастолы. Были идентифицированы зоны с низким и осциллирующим WSS, что связано с эндотелиальной дисфункцией и дегенерацией стенки сосуда, в то время как участки с высоким WSS указывали на возможную локальную деградацию сосуда. Полученные данные демонстрируют, что угол наклона аорты существенно усиливает изменения гемодинамики при АБА, тем самым повышая риск ослабления стенки и ее разрыва. Данное исследование подчеркивает перспективность CFD-моделирования для получения механистического понимания поведения и прогрессирования аневризм, а также для разработки неинвазивных методов оценки риска разрыва и поддержки клинического принятия решений.

An abdominal aortic aneurysm (AAA) is an enlarging dilation of the abdominal aorta at signifi-cant risk of rupture and death. During normal physiological conditions, pulsa-tile blood flow in the abdominal aorta displays largely laminar patterns, albeit localized disturbances due to branching vessels and geometric variations. The existence of an aneurysm also distorts vascular structure, leading to sophisticated flow dynamics that could foster disease progression. In the present study, haemodynamics in three-dimensional AAA models were studied with the help of computational fluid dynamics (CFD). Idealized aneurysm geometries with four extreme proximal neck angulations were taken into consideration with laminar flow and rigid arterial wall assumption. Simulations were carried out over the entire cardiac cycle to preserve the pulsatile flow's unsteadi-ness. Post-processing methods were used to analyse velocity distribution, pressure fields, streamlines, and wall shear stress (WSS). The findings showed that marked angu-lation of the proximal aortic neck caused asymmetric flow patterns, turbulence, and blood recirculation in the aneurysm sac, especially during diastole. Low and oscillatory WSS regions were mapped, which are implicated to cause endothelial dysfunction and wall degeneration, whereas zones of high WSS indicated possible localized vascular weaken-ing. These results illustrate that vessel angulation greatly enhances disturbed hemody-namics in AAA, thus augmenting the risk of wall weakening and rupture. This study out-lines the promise of CFD-based simulations to deliver mechanistic insights into aneu-rysm behavior and progression and to provide a non-invasive means of assessing rup-ture risk and to guide clinical decision-making.

The increase in pollution levels in recent years has increased the prevalence of pulmonary diseases. The accumulation of pollutant particles in the pulmonary tract is speculated to be one of the major reasons for the increase in chronic cases. This necessitates the study of the mechanism of particle deposition in human airways to develop better drug delivery systems. Aerosolized forms of drugs are commonly used to treat pulmonary diseases. The current study employed computational fluid dynamics (CFD) and discrete element method (DEM) techniques to study airflow patterns and particle deposition phenomena. An idealized 3D CAD model was developed based on available literature. A discretized finite-volume model was tested to ensure an independent solution. A user-defined function (UDF) was used to simulate realistic breathing dynamics for the respiration cycle. The aerosol particles of the calculated volume were mixed into the airflow domain. The analysis was conducted using ANSYS FLUENT CFD solver. This study found several regions of high turbulence in the upper human airways, with secondary flow structures exhibiting bifurcations and the glottal region. The study also found that the oral cavity and oropharynx regions with higher turbulence intensity had a concentrated deposition of particles. Most of the aerosol particles (5μm) were transported into the alveolar sacs, where they were absorbed into the bloodstream. The oral cavity and oropharynx have the highest pressure and particle deposition efficiency, while the trachea plays a crucial role in particle deposition during inhalation due to weak oscillatory flows and turbulence, especially in the tracheal region and lower respiratory tract. The oral cavity has the highest efficiency at 7.32%, while the trachea has the lowest at 0.4%. The overall deposition efficiency across all regions is 9.078%.This study did not account for the breakup of aerosol particles. Aerosol particles can break apart due to airflow and collisions, affecting their size and deposition efficiency. Ignoring this breakup could lead to inaccurate results, making accurate dosimetry essential for inhalation studies

Cardiovascular disease (CVD) is one major cause of morbidity caused by the progress of atherosclerosis without any symptoms and has a high risk of Transient Ischemic Stroke (TIS). The carotid bifurcation and bulb are the region where the blood flow is irregular, which may lead to the progression of the plague. The flow disruption due to stenosis in idealised carotid artery has been extensively investigated using Fluid Structure interaction (FSI). However, the haemodynamic of patient specific carotid artery has been intensively studied. In this study, a comparison of blood flow in healthy and stenosed (80% blockage in the carotid bulb region) was carried out using Two- way FSI analysis considering non-Newtonian blood viscosity and isotropic property for vessel wall. Haemodynamic parameters such as velocity streamline, pressure, vorticity, helicity, Time-Averaged Wall shear stress (TAWSS) and Oscillatory Shear Index (OSI) were analysed along with structural parameters such as wall displacement and von Mises stress. The comparison between healthy and stenosed arteries reveals that stenosis significantly increases the velocity magnitude due to the reduced flow area caused by plaque buildup. This narrowing also results in elevated pressure upstream of the stenosis. In both healthy and stenosed arteries, maximum deformation occurs near the bifurcation at the left and right lateral sections, with the highest von Mises Stress located near the internal wall of the flow divider. In stenosed arteries, the stress magnitude is six times higher than in healthy arteries, illustrating the profound effect stenosis has on haemodynamic. Overall, the analysis emphasizes how stenosis disrupts normal blood flow and alters bio-fluid dynamics in the carotid artery

Aircraft cabins have high occupant densities and may introduce the risk of COVID-19 contamination. In this study, a segment of a Boeing 767 aircraft cabin with a mixing type of air distribution system was investigated for COVID-19 deposition. A section of a Boeing 737-300 cabin, featuring four rows with 28 box-shaped mannequins, was used for simulation. Conditioned air entered through ceiling inlets and exited near the floor, simulating a mixed air distribution system. Cough droplets were modeled using the Discrete Phase Model from two locations: the centre seat in the second row and the window seat in the fourth row. These droplets had a mean diameter of 90 µm, an exhalation velocity of 11.5 m/s and a flow rate of 8.5 L/s. A high-quality polyhedral mesh of about 7.5 million elements was created, with a skewness of 0.65 and an orthogonality of 0.3. The SIMPLE algorithm and a second-order upwind finite volume method were used to model airflow and droplet dynamics. It was found that the ceiling accounted for the maximum concentration followed by the seats. The concentration of deposits was almost 50% more when the source was at window as compared to the centre seat. The Covid particles resided for longer duration when the source was at the centre of the cabin than when it was located near the widow.

Computational Fluid Dynamics (CFD) plays an important role in assessment of genesis and prognosis of atherosclerosis and as a promising tool for risk stratification. CFD is widely used by a majority of the researchers, although, many experimental studies show that the results obtained by CFD are inconsistent with the physio-pathological manifestations, which is mainly due to inconsistent definition of parameters, limited data availability and extreme complexity and heterogeneous behavior of plaque growth and its rupture. In this review, the results obtained by Computational Fluid Dynamics are summarized and an attempt is made to deduce the broad causes of various errors and possible solutions.