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Nonlinear Parameter Estimation Model for Dynamic Stability Analysis and Uncertainty Quantification of Six-Degree-of-Freedom Atmospheric Entry Capsules

Nonlinear Parameter Estimation Model for Dynamic Stability A...

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AIAA Science and Technology Forum and Exposition, AIAA SciTech Forum 2025

作者： Kassem, Ashraf Oz, Furkan Romeo, Shafi Al Salman Tiwari, Bipin San, Omer Kara, Kursat School of Mechanical and Aerospace Engineering Oklahoma State University StillwaterOK74078 United States Department of Mechanical Aerospace and Biomedical Engineering University of Tennessee KnoxvilleTN37996 United States

ISBN: (数字)9781624107238

ISBN: (纸本)9781624107238

As atmospheric entry vehicles descend through planetary atmospheres, they encounter complex, nonlinear aerodynamic phenomena and uncertain dynamic behaviors, making accurate estimation of dynamic stability coefficients critical for reliable entry, descent, and landing. This study addresses these challenges by introducing a novel Bayesian framework integrated with a six-degrees-of-freedom (6-DOF) dynamic model to determine stability coefficients and their associated uncertainties. A Markov Chain Monte Carlo (MCMC) inference technique, initialized via a nonlinear least squares approach, is employed to obtain posterior distributions of the stability parameters rather than relying solely on deterministic estimates. The 6-DOF equations of motion are first validated against two established 6-DOF simulation benchmarks, demonstrating excellent agreement and confirming the model’s credibility. Synthetic time series of aerodynamic angle data generated for a reference (Genesis) vehicle model serves as input for the inference process, enabling the recovery of original stability coefficients and the reconstruction of trajectories with rigorously quantified uncertainties. These results highlight the potential of the proposed Bayesian methodology to enhance the fidelity and robustness of dynamic stability analyses, ultimately supporting more reliable atmospheric entry mission design and execution. © 2025, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.

关键词： Markov chains

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A non-ideal solution theory for the mechanics and electrochemistry of charged membranes

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npj Computational Materials 2022年第1期8卷 1365-1378页

作者： Alain Boldini Maurizio Porfiri Center for Urban Science and Progress Department of Mechanical and Aerospace EngineeringNew York University Tandon School of Engineering370 Jay StreetBrooklyn11201NYUSA Center for Urban Science and Progress Department of Mechanical and Aerospace EngineeringDepartment of Biomedical EngineeringNew York University Tandon School of Engineering370 Jay StreetBrooklyn11201NYUSA

Understanding how ions and solvent molecules migrate within charged membranes is fundamental for advancing the analysis of biological membranes and the design of energy storage and production *** efforts highlighted a significant interplay between mechanics and electrochemistry in charged membranes,calling for the development of high-fidelity models to describe their ***,we propose a continuum theory of the chemoelectromechanics of charged membranes,accounting for potentially large deformations and non-idealities of the solution permeating the *** demonstrate the potential applications of our theory within the study of ionic polymer *** theory predicts sizeable effects of non-idealities and mechanical deformations,enabling insight into the role of mechanics on solute and solvent transport within charged membranes.

关键词： interaction. theory electrochemistry

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Translation of a sphere towards a rigid plane in an Oldroyd-B fluid

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Physical Review Fluids 2024年第8期9卷 083303页

作者： Tachin Ruangkriengsin Rodolfo Brandão Bimalendu Mahapatra Evgeniy Boyko Howard A. Stone Program in Applied and Computational Mathematics Department of Mechanical and Aerospace Engineering Faculty of Mechanical Engineering

We analyze the low-Reynolds-number translation of a sphere towards or away from a rigid plane in an Oldroyd-B fluid under two scenarios: prescribing the sphere's translational velocity, and prescribing the force on the sphere. Leveraging the lubrication approximation and a perturbation expansion in powers of the Deborah number, we develop a comprehensive theoretical analysis that yields analytical approximations for velocity fields, pressures, and forces acting on the sphere. Our framework aids in understanding temporal microstructural changes as the particle-wall gap evolves over time. In particular, we show that alterations in the polymer conformation tensor in response to geometric changes induce additional forces on the sphere. For cases with prescribed velocity, we present a theoretical approach for calculating resistive forces at any order in the Deborah number and utilize a reciprocal theorem to obtain higher-order corrections based on velocity fields in the previous orders. When the sphere translates with a constant velocity, the fluid viscoelasticity decreases the resistive force at the first order. However, at the second-order correction, the direction of the sphere's movement determines whether viscoelasticity increases or decreases the resistive force. For cases with prescribed force, we show that understanding the influence of viscoelasticity on the sphere's translational velocity necessitates a more intricate analysis even at low Deborah numbers. Specifically, we introduce an ansatz for constant force scenarios, and we derive solution forms for general prescribed forces using the method of multiple scales. We find that when a sphere undergoes sedimentation due to its own weight, the fluid viscoelasticity results in a slower settling process, reducing the leading-order sedimentation rate.

关键词： Complex fluids Low Reynolds number flows Lubrication theory Polymer conformation changes Rheology

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Numerical Modeling of Conical-Shaped Bone Marrow Biopsy Needle into Multilayer Iliac Crest Model

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Journal of engineering and Science in Medical Diagnostics and Therapy 2023年第1期6卷 011001页

作者： Nadda, Rahul Repaka, Ramjee Sahani, Ashish Kumar Department of Biomedical Engineering Indian Institute of Technology Ropar Punjab Rupnagar140001 India Department of Mechanical Engineering Indian Institute of Technology Ropar Punjab Rupnagar140001 India

Bone marrow biopsy (BMB) is a standard technique used in various therapies, research, diagnosis, and prognosis. The extensive forces during biopsy result in un-necessary stress concentrations that are primarily hazardous to weak end bones. To enhance protection and to better identify the risks of bone biopsy, it is essential to understand and predict the interaction of needles with multiple layers of skin and bone. The present investigation aimed to find out the numerical evaluation of forces involved in the insertion and extraction of the needle into multilayer iliac crest model. The insertion and extraction forces have been studied at different diameters of biopsy needles up to a depth of 15.35 mm and insertion speeds in the range of 1 mm/s to 10 mm/s. The results showed that the insertion and extraction forces vary according to the needle diameter and relative velocity among the needle and tissue layers. A linear force versus depth relationship has been obtained in the preliminary phase, and as the depth of insertion increases, the forces increase nonlinearly. At the end phase of penetration, the forces augmented more rapidly at a low insertion rate compared to the high insertion rate. © 2023 American Society of mechanical Engineers (ASME). All rights reserved.

关键词： Needles

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Corrosion Inhibition Efficiency of Biosynthesized Silver Nanoparticles Using Citrus aurantium Peels Extract

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Journal of Bio- and Tribo-Corrosion 2024年第3期10卷 1-24页

作者： Hamze, Zeina K. Faraj, Marwa Mhanna, Rami Younes, Ghassan El-Dakdouki, Mohammad H. Department of Chemistry Faculty of Science Beirut Arab University Riad El Solh Beirut11072809 Lebanon Biomedical Engineering Program Maroun Semaan Faculty of Engineering and Architecture American University of Beirut Beirut1107 2020 Lebanon

Corrosion is a detrimental persistent industrial conundrum that can cause the failure of operating equipment and weakening of construction assemblies, thus threatening the lives of humans, and accelerating the consumption of the natural metals reservoirs. In this study, we deployed green silver nanoparticles (AgNPs) as corrosion inhibitors for mild steel. Citrus aurantium peels aqueous extract (CAPE) mediated the bio-reduction of silver ions (Ag+) into silver nanoparticles (AgNPs) under optimized experimental conditions. The prepared nanoparticles were comprehensively characterized by various techniques for size, morphology, optical properties, crystallinity, and elemental composition. Phytochemical analysis showed that the plant extract is rich in phenolic compounds that facilitated the formation of metallic silver from Ag+ ions. The anticorrosion properties of CAPE and CAPE-AgNPs for mild steel in 0.5 M HCl were investigated by potentiodynamic polarization and electrochemical impedance spectroscopy techniques. The biosynthesized CAPE-AgNPs were more efficient than CAPE in slowing down corrosion with inhibition efficiency of 70% attained at 1000 ppm of the inhibitor. CAPE and CAPE-AgNPs acted as mixed-type corrosion inhibitors with dominance over the cathodic reaction. Fitting the experimental data into different isotherms demonstrated that the corrosion inhibition was an endothermic process that took place through physical adsorption. CAPE-AgNPs significantly reduced pitting and localized damage on the metal surface. These findings highlighted the utility of CAPE-AgNPs as efficient corrosion inhibitors in different industrial settings. © The Author(s), under exclusive licence to Springer Nature Switzerland AG 2024.

关键词： Silver nanoparticles

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Automated restricted Boltzmann machine classifier for early diagnosis of Parkinson’s disease using digitized spiral drawings

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Journal of Ambient Intelligence and Humanized Computing 2023年第1期14卷 175-189页

作者： Thakur, Mahima Dhanalakshmi, Samiappan Kuresan, Harisudha Senthil, Ramalingam Narayanamoorthi, R. Lai, Khin Wee Department of Electronics and Communication Engineering SRM Institute of Science and Technology Kattankulathur Chennai India Department of Mechanical Engineering SRM Institute of Science and Technology Kattankulathur Chennai India Department of Electrical and Electronics Engineering SRM Institute of Science and Technology Kattankulathur Chennai India Department of Biomedical Engineering Faculty of Engineering Universiti Malaya Kuala Lumpur Malaysia

Parkinson's disease (PD) is a neurodegenerative disorder that affects the elderly. PD affects the quality of life by causing motor and non-motor disabilities. Traditional PD diagnosis depends on the medical history, a review of symptoms, neurological and physical examinations by a medical specialist. Early detection of PD is a critical step towards providing prompt medical action. In artificial intelligence, computer-assisted methods for PD identification have recently received more attention. The present work focuses on the early detection of PD by logically analyzing time-series data collected during a spiral drawing assessment test of Parkinson’s and normal subjects using digital tablets. A preliminary machine learning approach is taken on static and dynamic drawings tests separately using logistic regression and Support Vector Machine classifier to observe accuracies. It is leveraging a recent novel strategy of employing Restricted Boltzmann machine (RBM) pipelined with multi-layer perceptron model classifier, which provides an accuracy of 95.32% by combining both static and dynamic spiral drawings assessments. The proposed approach is a successful candidate for detecting PD patients. The reported results of cost-effective computer tool-based PD symptom monitoring are helpful in telemedicine applications. © 2022, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.

关键词： Support vector machines

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Loss Balancing for Physics-Informed Neural Networks Considering Procedure for Solving Partial Differential Equations 13

Loss Balancing for Physics-Informed Neural Networks Consider...

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Joint 13th International Conference on Soft Computing and Intelligent Systems and 25th International Symposium on Advanced Intelligent Systems, SCIS and ISIS 2024

作者： Kojima, Manabu Otsuki, Kazuma Suzuki, Masato Abe, Masajiro Baba, Masaaki Yokota, Kazuya Master's Program in Mechanical Engineering Nagaoka University of Technology Nagaoka Japan Nagaoka University of Technology Department of System Safety Engineering Nagaoka Japan Nagaoka University of Technology Department of Mechanical Engineering Nagaoka Japan

ISBN: (纸本)9798350373332

With the development of machine learning, numerical analysis using neural networks has been devised. Remarkably, physics-informed neural networks (PINNs) enable physically consistent numerical analysis by introducing a loss function that conforms to relevant governing equations. Moreover, research is rapidly advancing for the application of PINNs to inverse analysis in areas such as physical property identification. For a PINN to learn governing equations, the weights of the loss functions should be properly determined because they have different roles in components such as boundary conditions, initial conditions, and governing equations. However, weight setting is generally challenging. We propose a loss balancing method considering the procedure for solving partial differential equations. The proposed method is validated through comparisons with conventional solvers. © 2024 IEEE.

关键词： Partial differential equations

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Vascular endothelial cellular mechanics under hyperglycemia and its role in tissue regeneration

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Regenerative Biomaterials 2024年第5期3卷 49-58页

作者： Kui Wang Yongmei Ge Yongshuai Yang Zhenjian Li Jiayi Liu Yizebang Xue Yuanjun Zhang Xiangchao Pang A.H.W.Ngan Bin Tang Department of Biomedical Engineering Southern University of Science and TechnologyShenzhen 518055China Department of Mechanical Engineering University of Hong KongHong Kong 999077China Guangdong Provincial Key Laboratory of Cell Microenvironment and Disease Research Shenzhen Key Laboratory of Cell MicroenvironmentShenzhen 518055China College of Materials Science and Engineering Central South University of Forestry and TechnologyChangsha 410004China

Diabetes is one of the most prevalent diseases *** tissue regeneration of diabetes patients is known to be rather tricky as the result of vascular dysfunction,and this leads to various clinical complications including diabetic foot *** vascular endothelial cells,which compactly line the inner surface of blood vessels,are responsible for the growth and maintenance of blood vessels and play an essential role in tissue *** the mechanical properties of cells are generally known to be regulated by physiological/pathological conditions,few studies have been performed to investigate vascular endothelial cellular mechanics under hyperglycemia and the biological functions related to tissue *** this study,we conduct a systematic investigation of this *** results suggested that the stiffness of human umbilical vein endothelial cells(HUVECs)can be significantly regulated by the glucose concentration,subsequently,leading to significant alterations in cell migration and proliferation capabilities that are closely related to tissue *** rearrangement of the cytoskeleton induced by hyperglycemia through Cdc42 was found to be one of the pathways for the alteration of the cell stiffness and the subsequent cell ***,we suggested that the inhibition of Cdc42 might be a promising strategy to facilitate various tissue regeneration for diabetes patients.

关键词： endothelial cell hyperglycemia stiffness migration Cdc42

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Design and Performance Comparison of Low Dropout Regulators for a 32-bit Microcontroller Using 22nm Technology 16

Design and Performance Comparison of Low Dropout Regulators ...

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16th IEEE Latin American Symposium on Circuits and Systems, LASCAS 2025

作者： Johnson, Emmanuel K. M. Lima, Luis Victor N. Campagnucci, Pamela. R. A. N. Haddad, Sandro A. P. Amaral, Wellington A. Munoz, Daniel M. University of Brasilia Mechatronics Graduate Program Department of Mechanical Engineering DF Brasilia Brazil University of Brasilia Faculty of Gama Electronics Engineering Undergraduate Program DF Brasilia Brazil

ISBN: (纸本)9798331522124

This paper presents a comparison between two LDOs (Low Dropout Regulators) developed for a PMIC (Power Management Integrated Circuit) responsible for powering a 32-bit microcontroller based on the RISC-V microarchitecture, designed in 22 nm technology. The microcontroller will be integrated with a radio frequency interface for IoT (Internet of Things) applications. Two LDOs were designed: one with external compensation and the other a capacitor-less LDO. Both operate with an input voltage of 2.5V, an output voltage of 0.8V, and a maximum current of 150mA. The externally compensated LDO exhibited greater stability in response to load variations and a higher PSRR (Power Supply Rejection Ratio), while the capacitor-less LDO demonstrated faster regulation speed and occupied a chip area similar to the externally compensated LDO. © 2025 IEEE.

关键词： Low power electronics

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Internet-Based Smartphone System for After-Stroke Hand Rehabilitation

Internet-Based Smartphone System for After-Stroke Hand Rehab...

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2023 International Conference on engineering, Science and Advanced Technology, ICESAT 2023

作者： Naser, Hussein Hammood, Husam Migot, Asaad Q. College of Engineering University of Thi-Qar Biomedical Engineering Department Nasiriyah Iraq College of Engineering University of Thi-Qar Mechanical Engineering Department Nasiriyah Iraq

ISBN: (纸本)9798350344400

Hand rehabilitation for after-stroke survived patients is crucial to be initiated very soon for good results in the recovery process. Traditional rehabilitation requires clinical supervision by a physiotherapist, so it can be costly, time consuming, and demotivating. This research suggests a low-cost online wearable hand rehabilitation system to support partially disabled patients with their hand rehabilitation. The proposed online system consists of two main parts, namely patient part, and therapist part. The patient part consists of a mobile phone app. and a Myo gesture control armband. The app. generates rehabilitation exercises and all other operations to help the patients do their exercises on their own with motivating graphics. Meanwhile, the Myo armband detects electromyographic (EMG) signals of patient's arm muscles and recognizes the gestures and movements of the hand. The system can classify these gestures and movements for correct and incorrect to track the patient's performance. On the other hand, the therapist part includes local performance and remote online monitoring portal for monitoring, analysis, and assessment of the patient's recovery progress. After completion of a given exercise, a performance report of the patient will be given locally and sent to the monitoring portal for assessment by the physiotherapist. The system was tested by healthy subjects to prove its efficiency with accuracy of 96.9%. The results showed a smooth performance and compatibility between the main two parts of the system. © 2023 IEEE.

关键词： Patient rehabilitation

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