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Two-way fluid-structure interaction of medium-sized heliostats

AIP Conference Proceedings 2019年第1期2126卷

作者： Joshua R. Wolmarans Ken J. Craig 1Graduate student Department of Mechanical and Aeronautical Engineering University of Pretoria Pretoria 0002 South Africa 2PrEng PhD Professor Department of Mechanical and Aeronautical Engineering University of Pretoria Pretoria 0002 South Africa

Vortex shedding and the resultant transient loadings on a medium sized heliostat are investigated in this paper. Reynolds-Averaged Navier-Stokes (RANS) Computational Fluid Dynamics (CFD) is used as a validation case along with laminar and Large Eddy Simulation Fluid-Structure Interaction (FSI) validation. 2-Dimensional unsteady RANS and FSI are performed where the shedding frequency is found at the experimentally predicted Strouhal number, which is also in the region of concern as confirmed via a modal analysis of the heliostat structure. Stress-Blended Eddy Simulation (SBES) is then used as a scale-resolving method in order to accurately simulate the transient peak loading and vortex shedding in three dimensions. The SBES simulation results show that the 2D URANS results captured one of the main vortex-shedding frequencies. Initial deformation results from a transient structural analysis using the temporal SBES heliostat surface pressure fields as input indicate that the method holds promise in predicting the transient response of heliostats.

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Surface tension assisted dynamic and uniform size generation of 3D spherical hydrogels (STA-DUH) 22

Surface tension assisted dynamic and uniform size generation...

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22nd International Conference on Miniaturized Systems for Chemistry and Life Sciences, MicroTAS 2018

作者： Koduri, Manohar Prasad Garden, Tom Hunt, John A. Henstock, James Curran, Judith Tseng, Fan-Gang International Intercollegiate PhD Program NTHU Hsinchu Taiwan Department of Mechanical Materials and Aerospace School of Engineering University of Liverpool United Kingdom School of Science and Technology Nottingham Trent University NottinghamNG11 8NS United Kingdom Institute of Ageing and Chronic Disease William Henry Duncan Building University of Liverpool United Kingdom Engineering and System Science Frontier Research Center on Fundamental and Applied Sciences of Matters National Tsing Hua University Taiwan

ISBN: (纸本)9781510897571

Technologies like additive manufacturing, microfluidics, and electrospray show a possibility of generating a variety of 3-Dimensional structures but seriously suffer in adapting and utilizing the wide variety of available biocompatible materials because of innate diverse physical and chemical properties of biomaterials. It is very important to have a technology which can be viable and dynamically adaptable for different types of materials in generating uniform structures. This work presents a novel cell-laden hydrogel generation using the surface tension phenomenon in controlling the size of the hydrogel. Copyright © (2018) by Chemical and Biological Microsystems Society. All rights reserved.

关键词： Surface tension

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A Scalable Deep Attention Mechanism of Instance Segmentation for the Investigation of Chromosome

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SLAS technology 2025年 33卷 100306页

作者： Neelam Umbreen Sara Ali Hasan Sajid Yasar Ayaz Shrooq Alsenan Yunyoung Nam So Yeon Kim Muhammad Baber Sial National University of Sciences and Technology (NUST) Islamabad Pakistan. Electronic address: neelamumbreen.phd@smme.edu.pk. National University of Sciences and Technology (NUST) Islamabad Pakistan Suzhou Industrial Park (SIP) Monash Research Institute of Science and Technology Monash University 8Q9C+R6W Suzhou Jiangsu China. School of Mechanical and Manufacturing Engineering (SMME) National University of Sciences and Technology (NUST) Islamabad NUST-COVENTRY Human-Robot Interaction (NC-HRI) Laboratory Pakistan Intelligent Field Robotics Laboratory (IFRL) National Center for Artificial Intelligence (NCAI) National University of Sciences and Technology (NUST) Islamabad Pakistan. Electronic address: sarababer@smme.nust.edu.pk. National University of Sciences and Technology (NUST) Islamabad Pakistan. Electronic address: hasan.sajid@smme.nust.edu.pk. Intelligent Field Robotics Laboratory (IFRL) National Center for Artificial Intelligence (NCAI) National University of Sciences and Technology (NUST) Islamabad Pakistan. Electronic address: yasar@smme.nust.edu.pk. Information Systems Department College of Computer and Information Sciences Princess Nourah bint Abdulrahman University P.O. Box 84428 Riyadh 11671 Saudi Arabia. Electronic address: shalsenan@pnu.edu.sa. Emotional and Intelligent Child Care Convergence Research Center Soonchunhyang University Asan 31538 Korea. Electronic address: ynam@sch.ac.kr. Department of Artificial Intelligence Department of Software and Computer Engineering Ajou University. Electronic address: jebi1771@ajou.ac.kr. School of Automation Science and Electrical Engineering Beihang University Beijing 100191 China. Electronic address: babersial@***.

Chromosome segmentation in metaphase images is a critical yet challenging task in cytogenetics and genomics due to the inherent complexity, variability in chromosome shapes, and the scarcity of high-quality annotated datasets. This study proposes a robust instance segmentation framework that integrates an automated annotation pipeline with an enhanced deep learning architecture to address these challenges. A novel dataset is introduced, comprising metaphase images and corresponding karyograms, annotated with precise instance segmentation information across 24 chromosome classes in COCO format. To overcome the labor-intensive manual annotation process, a feature-based image registration technique leveraging SIFT and homography is employed, enabling the accurate mapping of chromosomes from karyograms to metaphase images and significantly improving annotation quality and segmentation performance. The proposed framework includes a custom Mask R-CNN model enhanced with an Attention-based Feature Pyramid Network (AttFPN), spatial attention mechanisms, and a LastLevelMaxPool block for superior multi-scale feature extraction and focused attention on critical regions of the image. Experimental evaluations demonstrate the model's efficacy, achieving a mean average precision (mAP) of 0.579 at IoU = 0.50:0.95, surpassing the baseline Mask R-CNN and Mask R-CNN with AttFPN by 3.94% and 5.97% improvements in mAP and AP50, respectively. Notably, the proposed architecture excels in segmenting small and medium-sized chromosomes, addressing key limitations of existing methods. This research not only introduces a state-of-the-art segmentation framework but also provides a benchmark dataset, setting a new standard for chromosome instance segmentation in biomedical imaging. The integration of automated dataset creation with advanced model design offers a scalable and transferable solution, paving the way for tackling similar challenges in other domains of biomedical and cytogenetic imagi

关键词： Chromosome segmentation Instance segmentation, cytogenetics Mask R-CNN attention mechanism biomedical imaging multi-scale feature fusion

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Vibration caused by swing check valve closure

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IOP Conference Series: Materials Science and engineering 2019年第1期610卷

作者： Aly M El-Zahaby Mohamed Y Zakaria Yasser A F El-Samadony Ibrahim A Ismail Professor Mechanical Power Engineering Department Tanta University Tanta Egypt. Assistant professor Aerospace Engineering Department Military Technical College Cairo Egypt. Assoc. Professor Faculty of Engineering Tanta University Egypt. Also Assoc. Professor Faculty of Engineering Bruit Arab University Lebanon. PhD Student Mechanical Power Engineering Department Tanta University Tanta Egypt.

Check valve or non-return valve is a commonly used component in fluid control systems, the function of the check valve is to allow the fluid to flow in one direction and prevent it from flowing backward in the opposite direction. There are many types of check valve that differs in structure, material, theory of operation, applications, installations constraints, etc. The swing check valve type has many advantages like lower pressure drop, high valve flow coefficient, ease of maintenance, etc. In this paper, the swing check valve type will be investigated using a new mathematical model that avoids the inaccuracy in explicit models and time consumption of evaluating different coefficients in implicit models. The present model is validated by comparing to experimental data. Investigation of the swing check valve is carried out in order to determine the vibration produced by its closing action and closing response. Also the effect of equipping the swing check valve with a torsion spring is investigated to figure out the spring effect on the valve induced vibration.

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Adaptive Grasping using an Interphalangeal Flexion Angle Model and Particle Swarm Optimization

Adaptive Grasping using an Interphalangeal Flexion Angle Mod...

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IEEE International Conference on Biomedical Robotics and Biomechatronics

作者： Rinku Roy Ankush Roy Manjunatha Mahadevappa PhD scholar of Department of Advanced Technology Development Centre Indian Institute of Technology Kharagpur India B.Tech student of Department of Mechanical Engineering Indian Institute of Technology Kharagpur India Professor of School of Medical Sc

ISBN: (纸本)9781538681848

In power grasping, all the fingers and thumb are moved simultaneously towards the object centre to form a stable grip. The force imparted on the object while grasping is distributed among all the phalanges. The calculation of interphalangeal flexion angles is essential to ensure their contact with the object surface. For holding cylindrical and spherical shaped objects, the flexion angles follow inverse proportionality with the diameter of the object In this study, we have proposed a mathematical model by establishing a relationship of the interphalangeal flexion angles with the object diameter to replicate this natural manoeuvre in a hand prosthesis. We have derived that the sum of tangents of all the 14 interphalangeal flexion angles involved in power grasps, depends only on the length of intermediate phalanx of all the fingers and the object diameter. This relation eliminated the requirement of other phalangeal lengths and thus reduced overall variable complexity. To automate the computation of interphalangeal flexion angles, here we have implemented particle swarm optimisation (PSO). The relationship of the joint angle variation with the object diameter is used here as the fitness function. The resulted flexion angles were further evaluated for their efficacy in a simulated hand grasping model. In contrast to the generic prosthetic hands, where the joints are sequentially rotated according to their constraints from the object surface, this model allows simultaneous rotation of the joint angles according to the optimum fitness function using PSO.

关键词： Thumb Grasping Shape IP networks Mathematical model Prosthetic hand Indexes Prosthetic hand Grasp Thumb Internet Protocol networks Mathematical Model joint flexion Flexibility Angle Particle swarm optimization

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Surface quality simulation with neural networks in AZ91D Mg alloy milling

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IOP Conference Series: Materials Science and engineering 2019年第1期710卷

作者： M Kulisz I Zagórski J Korpysa Lublin University of Technology Management Faculty Department of Organisation of Enterprise 38 Nadbystrzycka Str. 20-618 Lublin Poland Lublin University of Technology Mechanical Engineering Faculty Department of Production Engineering 36 Nadbystrzycka Str. 20-618 Lublin Poland PhD student of Mechanical Engineering Lublin University of Technology 36 Nadbystrzycka Str. 20-618 Lublin Poland

The mathematical model presented in this paper describes the process of milling AZ91D Mg alloy with the TiAlN-coated tool. The experimental data from the neural network training served to determine the effect of various milling parameters on the surface roughness of the workpiece. The 2D roughness measurements were taken on the end-faces of specimens and focused on the set of three parameters – Ra, Rz and RSm. The tests were performed at constant parameters (tool geometry, workpiece strength properties and technological machine properties), variable parameters (cutting speed, feed per tooth, depth of cut) and output variables (Ra, Rz, Rsm). The simulations were executed by means of the artificial neural networks, modelled with Statistica Neural Network software. Two types of neural networks were employed: MLP (Multilayered Perceptron) and RBF (Radial Basis Function). The comparative analysis showed that the discrepancy between the results of simulation and the results obtained from experimental tests is on an acceptable level, not exceeding 15%. The above result confirms that ANNs can be successfully used as a tool for a selection of technological parameters, enabling obtaining the desired values of surface roughness parameters without the need for time-consuming machining tests.

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Wind Power Optimization: A Comparison of Meta-Heuristic Algorithms

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IOP Conference Series: Materials Science and engineering 2018年第1期376卷

作者： Rashmi P. Shetty A. Sathyabhama P Srinivasa Pai PhD Research scholar Department of Mechanical Engineering NITK Surathkal India Assistant Professor Department of Mechanical Engineering NITK Surathkal India Professor Department of Mechanical engineering NMAMIT Nitte India

The wind being a most promising renewable energy, has become a strong contender for fossil fuels. Optimizing the blade pitch angle of a wind turbine is important to obtain the maximum power output, as the other variables are considered to be uncontrollable. In this paper an effort has been made to compare performances of three different optimization algorithms namely Particle swarm optimization (PSO), Artificial bee colony (ABC) and cuckoo search (CS) for optimizing the blade pitch angle and hence optimize the power output of a 1.5 MW capacity, pitch regulated, three-bladed horizontal axis wind turbine operating at a large wind farm in central dry zone of Karnataka. The objective function development is done using Artificial Neural Network. The CS algorithm is found to be faster and more efficient as compared to ABC and PSO for the problem under consideration.

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3D Printing & mechanical Characteristion of Polylactic Acid and Bronze Filled Polylactic Acid Components

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IOP Conference Series: Materials Science and engineering 2018年第1期376卷

作者： K P Aveen F Vishwanath Bhajathari Sudhakar C Jambagi Assistant Professor Department of Mechanical Engineering Mangalore Institute of Technology and Engineering Moodabidri PhD Research Scholar Department of Mechanical Engineering NITK Surathkal India Assistant Professor Department of Mechanical Engineering NITK Surathkal India

Rapid prototyping (RP) technologies have emerged as fabrication methods to obtain engineering components within a short span of time. Desktop 3D printing, also referred as Additive Manufacturing (AM) technology is a powerful method of rapid prototyping technique that can fabricate three-dimensional engineering components. Poly Lactic acid (PLA) is a green alternative to petrochemical commodity plastics, used in packaging, agricultural products, disposable materials, textiles, and automotive composites, 3-D printing technology enables fabrication of PLA and bronze filled PLA, which has less tensile and flexural modulus. In order for 3D printed parts to be useful for engineering applications, the mechanical properties of the material will play an important role in the functioning of the components. In the present study, commercial grade PLA & bronze filled PLA has been considered as material for preparation of samples using desktop 3D printer. The samples were tested for their mechanical characteristics like Tensile and flexural strength properties. The test Samples were fabricated using 3D printing with different layer height and with different layer build-up speed. Comparison between the PLA & bronze filled PLA based on the experimental results are discussed and found PLA has superior tensile and flexural property when compared to Bronze filled PLA.

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Effect of fibre sizing on the interlaminar properties of polyamide matrix composites

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IOP Conference Series: Materials Science and engineering 2018年第1期426卷

作者： G Szebényi B Magyar Assistant professor BME Faculty of Mechanical Engineering Department of Polymer Engineering Budapest Hungary PhD student BME Faculty of Mechanical Engineering Department of Polymer Engineering Budapest Hungary

The aim of our study was to compare the interlaminar performance of PA based composites with different fiber sizing to investigate the importance of proper sizing. Composites were prepared by film-stacking from reinforcing materials with three available sizings compatible for vinylester, epoxy and polyamide. The composites were compared through standard static and self-developed dynamic and cyclic interlaminar shear test methods and scanning electron microscopy. The results showed that the proper sizing is crucial for the good mechanical performance of the composites, the PA sized fiber composites significantly better in all mechanical properties.

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The anatomic determinants of conductive hearing loss secondary to tympanic membrane perforation

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Journal of Otology 2017年第3期12卷 125-131页

作者： David J.Carpenter Debara L.Tucci David M.Kaylie Dennis O.Frank-Ito Division of Head and Neck Surgery & Communication Sciences Department of Surgery Duke University Medical Center Durham NC USA Computational Biology & Bioinformatics PhD Program Duke University Durham NC USA Department of Mechanical Engineering and Materials Science Duke University Durham NC USA

Objectives: Recent studies have introduced middle ear volume(MEV) as a novel determinant of perforation-induced conductive hearing loss(CHL) in a mechanism driven by trans-tympanic membrane pressure differences. The primary aims of this preliminary report are to: 1) correlate CHL with perforation size; 2) describe the relationship between CHL and MEV; and 3) compare CHL across a range of cholesteatoma ***: A retrospective pilot study was performed in 31 subjects with audiometry indicative of conductive hearing loss, temporal bone CT scans,and no prior middle ear surgery. Perforation size and MEV were analyzed with respect to CHL in a cohort of 10 perforated ears with no cholesteatoma. CHLs were compared in 3 groups defined by extent of cholesteatoma ***: Ears with large and small perforations showed mean ABG values of 32.0 ± 15.7 dB and 16.0 ± 16.4 dB, respectively. A direct relationship was observed between MEV and CHL for ears with large perforations across all frequencies, whereas this relationship for small perforations was frequency-dependent. Finally, a statistically significant increase in CHL was found across ears with increasing cholesteatoma involvement at 1000 Hz(X^2(2) = 9.786, p = 0.008),2000 Hz(x^2(2) = 8.455, p = 0.015),and 4000 Hz(x^2(2)= 8.253, p = 0.016).Conclusions: These pilot data suggest that greater perforation-induced conductive hearing losses may be associated with larger perforation sizes and cholesteatoma. The correlation between MEV and CHL may require additional study.

关键词： Perforation-induced hearing loss Conductive hearing loss Middle ear volume Three-dimensional volume reconstruction

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