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Microstructural image based convolutional neural networks for efficient prediction of full-field stress maps in short fiber polymer composites

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Defence technology（防务技术） 2023年第6期24卷 58-82页

作者： S.Gupta t.Mukhopadhyay v.Kushvaha Department of Civil Engineering Indian Institute of Technology JammuJ&KIndia Department of Aerospace Engineering Indian Institute of Technology KanpurUPIndia

the increased demand for superior materials has highlighted the need of investigating the mechanical properties of composites to achieve enhanced constitutive ***-reinforced polymer composites have emerged as an integral part of materials development with tailored mechanical ***,the complexity and heterogeneity of such composites make it considerably more challenging to have precise quantification of properties and attain an optimal design of structures through experimental and computational *** order to avoid the complex,cumbersome,and labor-intensive experimental and numerical modeling approaches,a machine learning(Ml)model is proposed here such that it takes the microstructural image as input with a different range of Young’s modulus of carbon fibers and neat epoxy,and obtains output as visualization of the stress component S11(principal stress in the x-direction).For obtaining the training data of the Ml model,a short carbon fiberfilled specimen under quasi-static tension is modeled based on 2D Representative Area Element(RAE)using finite element *** composite is inclusive of short carbon fibers with an aspect ratio of 7.5that are infilled in the epoxy systems at various random orientations and positions generated using the Simple Sequential Inhibition(SSI)*** study reveals that the pix2pix deep learning Convolutional Neural Network(CNN)model is robust enough to predict the stress fields in the composite for a given arrangement of short fibers filled in epoxy over the specified range of Young’s modulus with high *** CNN model achieves a correlation score of about 0.999 and l2 norm of less than 0.005 for a majority of the samples in the design spectrum,indicating excellent prediction *** this paper,we have focused on the stage-wise chronological development of the CNN model with optimized performance for predicting the full-field stress maps of the fiber-reinforced composite ***

关键词： Micromechanics of fiber-reinforced composites Machine learning assisted stress prediction Microstructural image-based machine learning CNN based stress analysis

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Evaluation of influence of cold atmospheric pressure argon plasma operating parameters on degradation of aqueous solution of Reactive Blue 198(RB-198)

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plasma Science and technology 2020年第5期22卷 114-125页

作者： K NAvANEEtHA pANDIYARAJ D vASU p v A pADMANABHAN M pICHUMANI R R DESHMUKH v KANDAvElU Research Division of plasma processing(RDpp) Department of PhysicsSri Shakthi Institute of Engineering and TechnologyChinniyam Palayam(post)Coimbatore-641062India Department of Nanoscience and technology Sri Ramakrishna Engineering CollegeCoimbatore-641022India Department of physics Institute of Chemical TechnologyMatungaMumbai 400019India Department of Chemistry Sri Shakthi Institute of Engineering and TechnologyL&T bypassChinniyam Palayam(post)Coimbatore-641062India

the intention of this work is to remove Reactive Blue 198(RB-198)dye components from simulated water solution using cold atmospheric pressure argon plasma *** solutions of RB-198 dye were treated as a function of various operating parameters such as applied potential,reaction time and distance between the plasma jet and surface of the *** efficiency of the degradation of RB-198 molecules was explored by means of Uv-vis *** reactive species involved during the treatment process were examined by optical emission spectra(OES).the present hydroxyl radicals(OH·radical)and hydrogen peroxide(H2O2)in the plasma-treated aqueous dye solutions were investigated using various spectroscopic *** other parameters such as total organic carbon(tOC),conductivity and p H were also *** toxicity of plasma-treated RB-198 solution was finally studied by diffusion bacterial analysis and by tracking seed germination *** results show that a higher degradation percentage of99.27%was acquired for the RB-198 treated at higher reaction time and applied potential,and shorter distance between the plasma jet and water *** may be due to the formation of various reactive oxygen(OH·radical,atomic oxygen(O)and H2O2)and nitrogen species(nitric oxide(NO)radicals and N2 second positive system(N2 SpS))during the processes as confirmed by OES analysis and other spectroscopy ***(17.7%-81.8%)and pH(7.5-3.4)values of the plasma-treated RB-198 decreased significantly with respect to various operation parameters,which indicates the decomposition of RB-198 molecules in the aqueous ***,the conductivity of plasma-treated RB-198 aqueous solutions was found to have increased linearly during the plasma treatment due to the formation of various ionic species in aqueous *** toxicity analysis clearly exhibits the non-toxic behavior of plasma-treated RB-198 aqueous solution towards the bacterial growth and germination of see

关键词： RB-198 degradation non-toxicity cold atmospheric pressure plasma jet

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Goal-Oriented Anisotropic hp-Adaptive Discontinuous Galerkin Method for the Euler Equations

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Communications on Applied Mathematics and Computation 2022年第1期4卷 143-179页

作者： vít Dolejší Filip Roskovec Faculty of Mathematics and physics Charles UniversitySokolovská8318675 PragueCzech Republic

We deal with the numerical solution of the compressible Euler equations with the aid of the discontinuous Galerkin(DG)method with focus on the goal-oriented error estimates and *** analyse the adjoint consistency of the DG scheme where the adjoint problem is not formulated by the differentiation of the DG form and the target functional but using a suitable linearization of the nonlinear ***,we present the goal-oriented anisotropic hp-mesh adaptation method for the Euler *** theoretical results are supported by numerical experiments.

关键词： Euler equations Discontinuous Galerkin method target functional Adjoint consistency Anisotropic hp-mesh adaptation

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Structural, elemental, optical and magnetic study of Fe doped ZnO and impurity phase formation

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progress in Natural Science:Materials International 2014年第2期24卷 142-149页

作者： S.Karamat R.S.Rawat p.lee t.l.tan R.v.Ramanujan Natural Science and Science Education National Institute of Education Nanyang Technological University COMSAtS Institute of Information technology Department of physics Middle East Technical University School of Material Science and Engineering Nanyang Technological University Nanyang Avenue

We have prepared a series of(ZnO)1-x(Fe2O3)x≤0.10bulk samples with various concentrations of Fe dopant by ball milling and investigated their structural, compositional, optical and magnetic properties by means of X-ray diffraction(XRD), X-ray photoelectron spectroscopy(XpS),Raman spectrometer and vibrating sample magnetometer(vSM), respectively. Information about different impurity phases was obtained through Rietveld refinements of XRD data analysis. XpS results showed different valence states(Fe2+ tand Fe3+) supported by shaking satellite peaks in samples. With increasing Fe doping percentage, the crystal quality deteriorated and a shift of E2 low band(characteristic of ZnO) has been observed in Raman spectra. Energy band gap estimated from reflectance Uv–vis spectroscopy showed shift for all bulk samples. the magnetic behavior was examined using a vibrating sample magnetometer(vSM), indicating ferromagnetic behavior at room temperature(300 K). the effective magnetic moment per Fe atom decreases with increase in doping percentage which indicates that ferromagnetic behavior arises from the substitution of Fe ions in the ZnO lattice.

关键词： Fe doped ZnO Dilute magnetic semiconductor Rietveld refinements X-ray spectroscopy Band gap Magnetic moment

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Development of cost effective personnel armour through structural hybridization

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Defence technology（防务技术） 2020年第6期16卷 1089-1097页

作者： p.Rama Subba Reddy t.Sreekantha Reddy I.Srikanth Juhi Kushwaha v.Madhu Defence Metallurgical Research laboratory Hyderabad500058India Advanced Systems laboratory Hyderabad500058India

the objective of the present study is to develop cost effective thermoplastic hybrid laminate using Dyneema®HB50 and tensylon®HSBD 30A through structural hybridization *** having 20 mm thickness were fabricated and subjected to 7.6239 mm mild steel core projectile with an impact velocity of 730±10 ms*** such as energy absorption,back face deformation and rate of back face deformation were measured as a function of hybridization *** was observed that hybrid laminate with 50:50 ratio(w/w)of tensylon®and Dyneema®with tensylon®as front face showed 200%more energy absorption when compared to 100%tensylon®laminate and showed equal energy absorption as that of expensive 100%Dyneema®***,hybrid laminate with tD50:50 ratio showed 40%lower in terms of final back face deformation than Dyneema®*** of back face deformation was also found to be slow for hybrid laminate as compared to Dyneema®*** mechanical analysis showed that,tensylon®laminate has got higher stiffness and lower damping factor than Dyneema®and hybrid *** interface between tensylon®and Dyneema®layers was found to be separating during the penetration process due to the poor interfacial *** behaviour of laminates for different hybridization ratios were studied by sectioning the impacted *** was observed that,the tensylon®laminate has undergone shear cutting of fibers as major failure mode whereas the hybrid laminate showed shear cutting followed by tensile stretching,fiber pull out and *** inputs are highly useful for body armour applications to design cost effective armour with enhanced performance.

关键词： Dyneema® tensylon® Hybrid laminate Ballistic impact Energy absorption Back face signature

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Remote heart rate measurement using low-cost RGB face video： a technical literature review

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Frontiers of Computer Science 2018年第5期12卷 858-872页

作者： philipp v. ROUASt Marc t. p. ADAM Raymond CHIONG David CORNFORtH Ewa lUX Institute of Information Systems and Marketing Karlsruhe Institute of Technology Karlsruhe 76133 Germany School of Electrical Engineering and Computing The University of Newcastle Callaghan NSW 2308 Australia

Remote photoplethysmography （rppG） allows remote measurement of the heart rate using low-cost RGB imaging equipment. In this study, we review the development of the field of rppG since its emergence in 2008. We also classify existing rppG approaches and derive a framework that provides an overview of modular steps. Based on this framework, practitioners can use our classification to design algorithms for an rppG approach that suits their specific needs. Researchers can use the reviewed and classified algorithms as a starting point to improve particular features of an rppG algorithm.

关键词： affective computing heart rate measurement remote non-contact camera-based photoplethysmography

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Geospatial analysis of forest fragmentation in Uttara Kannada District, India

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Forest Ecosystems 2016年第3期3卷 206-220页

作者： Ramachandra t v Bharath Setturu Subash Chandran Energy & Wetlands Research Group Center for Ecological Sciences（CES） Indian Institute of Science Centre for Sustainable technologies (astra) Bangalore Karnataka 560 012 India Centre for infrastructure Sustainable Transportation and Urban Planning（CiSTUP） Indian Institute of Science Bangalore Karnataka 560 012 India

Background： landscapes consist of heterogeneous interacting dynamic elements with complex ecological, economic and cultural attributes. these complex interactions help in the sustenance of natural resources through bio-geochemical and hydrological cycling. the ecosystem functions are altered with changes in the landscape structure, Fragmentation of large contiguous forests to small and isolated forest patches either by natural phenomena or anthropogenic activities leads to drastic changes in forest patch sizes, shape, connectivity and internal heterogeneity, which restrict the movement leading to inbreeding among Meta populations with extirpation of species. Methods： landscape dynamics are assessed through land use analysis by way of remote sensing data acquired at different time periods. Forest fragmentation is assessed at the pixel level through computation of two indicators, i.e., pf （the ratio of pixels that are forested to the total non-water pixels in the window） and p~ （the proportion of all adjacent （cardinal directions only） pixel pairs that include at least one forest pixel, for which both pixels are forested）. Results： Uttara Kannada District has the distinction of having the highest forest cover in Karnataka State, India. this region has been experiencing changes in its forest cover and consequent alterations in functional abilities of its ecosystem. temporal land use analyses show the trend of deforestation, evident from the reduction of evergreen - semi evergreen forest cover from 57.31% （1979） to 32.08 % （2013） Forest fragmentation at the landscape level shows a decline of interior forests 64.42 % （1979） to 25.62 % （20] 3） and transition of non-forest categories such as crop land, plantations and built-up areas, amounting now to 47.29 %. pCA prioritized geophysical and socio variables responsible for changes in the landscape structure at local levels. Conclusion： terrestrial forest ecosystems in Uttara Kannada District of Central Western Ghats have be

关键词： land use dynamics Forest fraqmentation Interior forests Biodiversity Geophysical variables

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A Convolutional Neural Network Classifier vGG-19 Architecture for lesion Detection and Grading in Diabetic Retinopathy Based on Deep learning

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Computers, Materials & Continua 2021年第1期66卷 827-842页

作者： v.Sudha t.R.Ganeshbabu Department of Electronics and Communication Engineering Pavai College of TechnologyNamakkal637018India Department of Electronics and Communication Engineering Muthayammal Engineering CollegeRasipuram637408India

Diabetic Retinopathy(DR)is a type of disease in eyes as a result of a diabetic condition that ends up damaging the retina,leading to blindness or loss of *** and physiological retinal variations involving slowdown of blood flow in the retina,elevation of leukocyte cohesion,basement membrane dystrophy,and decline of pericyte cells,*** DR in its initial stage has no symptoms,early detection and automated diagnosis can prevent further visual *** this research,using a Deep Neural Network(DNN),segmentation methods are proposed to detect the retinal defects such as exudates,hemorrhages,microaneurysms from digital fundus images and then the conditions are classified accurately to identify the grades as mild,moderate,severe,no pDR,pDR in ***,saliency detection is applied on color images to detect maximum salient foreground objects from the ***,structure tensor is applied powerfully to enhance the local patterns of edge elements and intensity changes that occur on edges of the ***,active contours approximation is performed using gradient descent to segment the lesions from the ***,the output images from the proposed segmentation process are subjected to evaluate the ratio between the total contour area and the total true contour arc length to label the classes as mild,moderate,severe,No pDR and *** on the computed ratio obtained from segmented images,the severity levels were ***,statistical parameters like the mean and the standard deviation of pixel intensities,mean of hue,saturation and deviation clustering,are estimated through K-means,which are computed as features from the output images of the proposed segmentation *** these derived feature sets as input to the classifier,the classification of DR was ***,a vGG-19 deep neural network was trained and tested using the derived feature sets from the KAGGlE fundus image dataset containing 35,126 images in

关键词： Diabetic retinopathy saliency map structure tensor gradient descent method exudates haemorrhages microaneurysms vGG-19

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CREEp BEHAvIOR MODElING OF UDIMEt 720li SUpERAllOY

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Acta Metallurgica Sinica(English letters) 2005年第1期18卷 65-73页

作者： v.lupinc M.Maldini l.Z.Zhou J.t.Guo Isfitutoperl＇EnergedcaeperleInterfasi ConsigfioNazionaledelleRicercheCNR-IENI20125MilanItaly Isfitutoperl＇EnergedcaeperleInterfasi ConsigfioNazionaledelleRicercheCNR-IENI20125MilanItaly／／InstituteofMetalResearchTheChineseAcademyofSciencesShenyang110016China InstituteofMetalResearch TheChineseAcademyofSciencesShenyang110016China

Constant load creep tests on isothermally forged Udimet 720li, an advanced superalloy for gas turbine disc application, were run in the stress/temperature field 900-450Mpa/650-700 ℃ producing rupture times in the 20-5000h range. the creep curves have shown a predominant accelerating creep stage, that has been described by the following equation: where ε min depends on stress and temperature, while parameter C depends mainly on stress. A strain dependent damage, defined by the parameter C, causes the accelerating creep stage at stresses lower than 750Mpa, whilst its contribution to the creep strain acceleration is less important at higher stresses. the model rationalizes the different behaviors at high and low stress and has been validated with variable stress and temperature creep behavior.

关键词： Udimet 720li creep creep curve shape creep damage

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tuning the particle size,physical properties,and photocatalytic activity of Ag_(3)pO_(4)materials by changing the Ag^(+)/pO_(4)^(3-)ratio

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Chinese physics B 2023年第3期32卷 561-568页

作者： Hung N M Oanh l t M Chung D p thang D v Mai v t Hang l t Minh N v Center for Nano Science and technology Hanoi National University of Education136 Xuan Thuy RoadCau Giay DistrictHanoi 100000Vietnam Department of physics Hanoi National University of Education136 Xuan Thuy RoadCau Giay DistrictHanoi 100000Vietnam Hanoi University of Mining and Geology Duc Thang WardNorth Tu Liem DistrictHanoi 100000Vietnam Institute of Materials Science Vietnam Academy of Science and Technology18 Hoang Quoc VietHanoi 100000Vietnam Faculty of Basic Sciences Hanoi University of Natural Resources and Environment41 A Phu Dien RoadNorth Tu LiemHanoi 100000Vietnam

this study demonstrates the influence of the Ag^(+)/pO_(4)^(3-)ratio in precursor solution on the crystal structural formation,morphology,physical properties,and photocatalytic performance of a Ag_(3)pO_(4)photocatalyst that is fabricated,using a facile precipitation method,from AgNO_(3)and Na2HpO_(4)·12H_(2)*** material characterizations were carried out using x-ray diffraction(XRD),scanning electron microscopy(SEM),energy-dispersive x-ray spectroscopy(EDX),Brunauer–Emmett–teller(BEt)surface area,Fourier transform infrared(FtIR)absorption,Raman scattering,x-ray photoelectron spectroscopy(XpS),Uv-vis absorption,and photoluminescence(pl).the results show that Ag_(3)pO_(4)crystallizes better when the excess pO_(4)^(3-)content increases,and the lattice parameters decrease slightly,while the crystal diameter and the particle size *** change is also observed in the Raman scattering and FtIR spectra with the increase in the vibration frequency of the[pO_(4)]*** compression of the[pO_(4)]unit was also confirmed in the XpS spectra with the shift of p 2p peaks toward higher binding *** photocatalytic results showed that the samples synthesized from excess pO_(4)^(3-)solution exhibited higher photocatalytic performance compared to the sample with a Ag^(+)/pO_(4)^(3-)ratio of 3:1.A sample prepared from the precursor solution with a Ag^(+)/pO_(4)^(3-)ratio of 3:1.5 was optimal for RhB decomposition under both visible light and natural sunlight,completely decomposing 10 ppm RhB after 15 minutes of xenon lamp irradiation and after 60 minutes under solar light *** is attributed to the high crystallinity,small particle size and low electron–hole recombination rate of the sample.

关键词： morphology photocatalytic Ag^(+)/pO_(4)^(3-)ratio visible light

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