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Nonlinear aspects of energy dissipation in wood-panel joints sara Casciati

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Earthquake Engineering and Engineering Vibration 2007年第4期6卷 259-268页

作者： sara Casciati AsTRA Dept. School of Architecture University of Catania at Siracusa 96100 Siracusa Italy

The joints connecting vertical and horizontal elements are the ＂weak link＂ in structural systems assembled from wood panels. If they are too weak, local failures may occur, resulting in performance that is significantly below expectations. If they are too resistant, the joints may be unable to dissipate energy during vibrations, thus possibly initiating a fast progressive failure. This paper re-processes and re-elaborates the results of shaking table tests previously carried out by the author and other co-workers. The goal is to assess the feasibility of a joint which is able to dissipate energy during vibration, without degrading the connection performance.

关键词： dynamic excitation energy dissipation wood panels joint monitoring system shaking table tests

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Automatic characterization of spherical metal powders by microscope image analysis:a parallel computing approach

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Journal of Iron and steel Research International 2023年第11期30卷 2293-2300页

作者： Xiang Li Linyi Cui sara shonkwiler sara McMains University of California BerkeleyBerkeleyCA94720USA The Hong Kong Polytechnic University Hong KongChina

The microstructural characteristics of spherical metal powders play an important role in determining the quality of mechanical parts manufactured by powder metallurgy *** the individual powder particles from their microscopic images is one of the most convenient and cost-efficient methods for the analysis of powder *** numerous image processing algorithms have been developed for automating the powder particle identification process,they perform less accurately in identifying adjacent particles that are heavily overlapped in their image *** propose an automatic algorithm to robustly and accurately identify spherical powder particles,especially heavily overlapped particles,from their microscope images.A parallel computing framework is designed to further enhance the computational efficiency of the proposed *** characteristics such as particle size distribution and the location of potential satellite particles have been derived from our identification *** accuracy and efficiency of our algorithm are validated by real-world scanning electron microscope images,outperforming other existing methods and achieving both precision and recall above 99%.

关键词： computing image overlapped

Geological Controls and Prospectivity Mapping for Manganese Ore Deposits Using Predictive Modeling Comparison:An Integration of Outcrop and Remote sensing Data,sinai Microplate,Egypt

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Journal of Earth science 2023年第2期34卷 588-608页

作者： sara Zamzam Geology Department Faculty of ScienceZagazig UniversityZagazig 44519Egypt

One of the most controversial minerals in their origin and occurrence around the world is manganese *** Abu Zenima area is rated one of the most economically important places where manganese ore deposits(Mn ODs)are located in the southwest sinai microplate,*** deposits are confined with the Um Bogma Formation(UBF)and the reserves of this region are relatively *** this study,optical and radar data are used in a new challenge as an attempt to reach the closest controls and setting of Mn ***,Frequency Ratio(FR)and Logistic Regression(LogR)predictive models are applied to integrate different geospatial thematic maps,to predict new potential resource zones for increasing the ranges of mining ***8 OLI,sentinel-2A Multi spectral Instrument and Radar(sentinel-1B)data are combined for mapping Mn ODs locations and their relationship with geological structures and the surrounding *** ratio,Principal and Independent Component Analysis techniques and four classification algorithms were implemented to the optical’VNIR and sWIR ***,the interferometric processing steps for sentinel-1 data were made for understanding the tectonic features in the *** FR and LogR models are validated during fieldwork with known Mn ODs *** indicate that processed images are capable of differentiation of UBF which broadly distributed in the central and southern parts of the *** ODs possibly formed by thermal events that attributed to paleo-volcanic events before the rift *** high accuracy of LogR model(0.902)suggests that high Mn ODs potential zones are identified within the intersected fault zones near granitic *** integration is recommended for discriminating hydrothermally Mn ODs in other arid geographic regions.

关键词： manganese deposits Abu Zenima Landsat8 oli sentinel data fault zones predictive modeling remote sensing

Variant Wasserstein Generative Adversarial Network Applied on Low Dose CT Image Denoising

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Computers, Materials & Continua 2023年第5期75卷 4535-4552页

作者： Anoud A.Mahmoud Hanaa A.sayed sara s.Mohamed Department of Mathematics and Computer science Faculty of ScienceNew Valley UniversityNew Valley72511Egypt Department of Computer science College of Computer Science and Engineering Taibah UniversityMedina42221KSA Department of Mathematics Faculty of ScienceAssiut UniversityAssiut71516Egypt

Computed Tomography(CT)images have been extensively employed in disease diagnosis and treatment,causing a huge concern over the dose of radiation to which patients are *** the radiation dose to get a better image may lead to the development of genetic disorders and cancer in the patients;on the other hand,decreasing it by using a Low-Dose CT(LDCT)image may cause more noise and increased artifacts,which can compromise the ***,image reconstruction from LDCT image data is necessary to improve radiologists’judgment and *** study proposed three novel models for denoising LDCT images based on Wasserstein Generative Adversarial Network(WGAN).They were incorporated with different loss functions,including Visual Geometry Group(VGG),structural similarity Loss(ssIM),and structurally sensitive Loss(ssL),to reduce noise and preserve important information on LDCT images and investigate the effect of different types of loss ***,experiments have been conducted on the Graphical Processing Unit(GPU)and Central Processing Unit(CPU)to compare the performance of the proposed *** results demonstrated that images from the proposed WGAN-ssIM,WGAN-VGG-ssIM,and WGAN-VGG-ssL were denoised better than those from state-of-the-art models(WGAN,WGAN-VGG,and sMGAN)and converged to a stable equilibrium compared with WGAN and *** proposed models are effective in reducing noise,suppressing artifacts,and maintaining informative structure and texture details,especially WGAN-VGG-ssL which achieved a high peak-signalto-noise ratio(PNsR)on both GPU(26.1336)and CPU(25.8270).The average accuracy of WGAN-VGG-ssL outperformed that of the state-ofthe-art methods by 1 *** prove that theWGAN-VGG-ssL is more stable than the other models on both GPU and CPU.

关键词： Machine learning deep learning image denoising low dose CT loss function

simultaneous effects of magnetic field and space porosity on compressible Maxwell fluid transport induced by a surface acoustic wave in a microchannel

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Chinese Physics B 2013年第12期22卷 323-332页

作者： Khaled s.Mekheimer soliman R.Komy sara I.Abdelsalam Mathematics & statistics Department Faculty of Science Taif University Department of Mathematics Faculty of Science (Men) Al-Azhar University Department of Mathematics Faculty of Science Helwan University Basic science Department Faculty of Engineering The British University in Egypt

Peristaltic motion induced by a surface acoustic wave of a viscous, compressible and electrically conducting Maxwell fluid in a confined parallel-plane microchannel through a porous medium is investigated in the presence of a constant magnetic field. The slip velocity is considered and the problem is discussed only for the free pumping case. A perturbation technique is employed to analyze the problem in terms of a small amplitude ratio. The phenomenon of a “backward flow” is found to exist in the center and at the boundaries of the channel. In the second order approximation, the net axial velocity is calculated for various values of the fluid parameters. Finally, the effects of the parameters of interest on the mean axial velocity, the reversal flow, and the perturbation function are discussed and shown graphically. We find that in the non-Newtonian regime, there is a possibility of a fluid flow in the direction opposite to the propagation of the traveling wave. This work is the most general model of peristalsis created to date with wide-ranging applications in biological, geophysical and industrial fluid dynamics.

关键词： peristaltic flow Maxwell fluid porous medium slip flow microchannel

Couple stress fluid flow in a rotating channel with peristalsis

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Journal of Hydrodynamics 2018年第2期30卷 307-316页

作者： Y.Abd elmaboud sara I.Abdelsalam Kh.s.Mekheimer Mathematics Department Faculty of Science and Arts Khulais University Of Jeddah Mathematics Department Faculty of Science Al-Azhar University (Assiut Branch) Department of Mechanical Engineering University of CaliforniaRiverside USA Basic science Department Faculty of Engineering The British University in Egypt Mathematics Department Faculty of Science Al-Azhar University

This article describes a new model for obtaining closed-form semi-analytical solutions of peristaltic flow induced by sinusoidal wave trains propagating with constant speed on the walls of a two-dimensional rotating infinite channel. The channel rotates with a constant angular speed about the z-axis and is filled with couple stress fluid. The governing equations of the channel deformation and the flow rate inside the channel are derived using the lubrication theory approach. The resulting equations are solved, using the homotopy perturbation method（HPM）, for exact solutions to the longitudinal velocity distribution, pressure gradient, flow rate due to secondary velocity, and pressure rise per wavelength. The effect of various values of physical parameters, such as, Taylor＇s number and couple stress parameter, together with some interesting features of peristaltic flow are discussed through graphs. The trapping phenomenon is investigated for different values of parameters under consideration. It is shown that Taylor＇s number and the couple stress parameter have an increasing effect on the longitudinal velocity distribution till half of the channel, on the flow rate due to secondary velocity, and on the number of closed streamlines circulating the bolus.

关键词： Homotopy perturbation method (HPM) couple stress fluid rotating channel peristaltic transport

A Voronoi diagram approach for detecting defects in 3D printed fiber-reinforced polymers from microscope images

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Computational Visual Media 2023年第1期9卷 41-56页

作者： Xiang Li sara McMains University of California Berkeley BerkeleyCalifornia94720USA

Fiber-reinforced polymer(FRP)composites are increasingly popular due to their superior strength to weight *** contrast to significant recent advances in automating the FRP manufacturing process via 3D printing,quality inspection and defect detection remain largely manual and *** this paper,we propose a new approach to automatically detect,from microscope images,one of the major defects in 3D printed FRP parts:fiber-deficient areas(or equivalently,resin-rich areas).From cross-sectional microscope images,we detect the locations and sizes of fibers,construct their Voronoi diagram,and employ-shape theory to determine fiber-deficient *** Voronoi diagram and-shape construction algorithms are specialized to exploit typical characteristics of 3D printed FRP parts,giving significant efficiency *** algorithms robustly handle real-world inputs containing hundreds of thousands of fiber cross-sections,whether in general or non-general position.

关键词： 3D printing(3DP) microscope image processing fiber-reinforced polymer(FRP) Voronoi diagrams -shapes resin-rich areas

solid-state impedance spectroscopy studies of dielectric properties and relaxation processes in Na_(2)O–V_(2)O_(5)–Nb_(2)O_(5)–P_(2)O_(5) glass

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International Journal of Minerals,Metallurgy and Materials 2024年第1期31卷 186-196页

作者： sara Marijan Luka Pavic Division of Materials Chemistry Ruđer Boskovic InstituteBijenicka 54HR-10000 ZagrebCroatia

solid-state impedance spectroscopy(ss-Is)was used to investigate the influence of structural modifications resulting from the addition of Nb2O5 on the dielectric properties and relaxation processes in the quaternary mixed glass former(MGF)system 35Na_(2)O–10V_(2)O_(5)–(55-x)P_(2)O_(5)–xNb_(2)O_(5)(x=0–40,mol%).The dielectric parameters,including the dielectric strength and dielectric loss,are determined from the frequency and temperature-dependent complex permittivity data,revealing a significant dependence on the Nb2O5 *** transition from a predominantly phosphate glass network(xsphate glass net-work(10≤x≤20,region II)leads to an increase in the dielectric parameters,which correlates with the observed trend in the direct-cur-rent(DC)*** the predominantly niobate network(x≥25,region III),the highly polarizable nature of Nb5+ions leads to a fur-ther increase in the dielectric permittivity and dielectric *** is particularly evident in Nb-40 glass-ceramic,which contains Na_(13)Nb_(35)O_(94) crystalline phase with a tungsten bronze structure and exhibits the highest dielectric permittivity of 61.81 and the lowest loss factor of 0.032 at 303 K and 10 *** relaxation studies,analyzed through modulus formalism and complex impedance data,show that DC conductivity and relaxation processes are governed by the same mechanism,attributed to ionic *** contrast to glasses with a single peak in frequency dependence of imaginary part of electrical modulus,M″(ω),Nb-40 glass-ceramic exhibits two distinct contributions with similar relaxation *** high-frequency peak indicates bulk ionic conductivity,while the additional low-fre-quency peak is associated with the grain boundary effect,confirmed by the electrical equivalent circuit(EEC)*** scaling characteristics of permittivity and conductivity spectra,along with the electrical modulus,validate time-temperature superposition and demonstrate a

关键词： phosphate glasses glass-ceramics impedance spectroscopy dielectric properties relaxation processes permittivity scaling conductivity scaling modulus formalism

Impact of demand growth on the capacity of long-duration energy storage under deep decarbonization

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Clean Energy 2024年第4期8卷 237-247页

作者： sara Ashfaq Ilyass El Myasse Daming Zhang Ahmed s.Musleh Carnegie Institution Stanford UniversityStanfordCAUSA Electric Power Research Institute(EPRI) Palo AltoCAUSA EEIs Laboratory ENSET MohammediaHassan II UniversityCasablancaMorocco school of Electrical Engineering and Telecommunications University of New South WalesSydneyAustralia

The weather-dependent uncertainty of wind and solar power generation presents a challenge to the balancing of power generation and demand in highly renewable electricity *** energy storage can provide flexibility to firm up the variability of renewables and to respond to the increased load demand under decarbonization *** paper explores how the battery energy storage capacity requirement for compressed-air energy storage(CAEs)will grow as the load demand *** we used an idealized lowest-cost optimization model to study the response of highly renewable electricity systems to the increasing load demand of California under deep *** show that providing bulk CAEs to the zero-emission power system offers substantial benefits,but it cannot fully compensate for the 100%variability of highly renewable power *** capacity requirement of CAEs increases by≤33.3%with a 1.5 times increase in the load demand and by≤50%with a two-times increase in the load *** this analysis,a zero-emission electricity system operating at current costs becomes more cost-effective when there is firm power *** least competitive nuclear option plays this role and reduces system costs by 16.4%,curtails the annual main node by 36.8%,and decreases the CAEs capacity requirements by≤80.7%in the case of a double-load *** CAEs has potential in addressing renewable variability,its widespread deployment is constrained by geographical,societal,and economic fac***,if California is aiming for an energy system that is reliant on wind and solar power,then an additional dispatchable power source other than CAEs or similar load flexibility is *** fully harness the benefits of bulk CAEs,the development and implementation of cost-effective approaches are crucial in significantly reducing system costs.

关键词： compressed-air energy storage deep decarbonization macro-energy modelling load growth renewable energy