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Prediction of Bandwidth of Metamaterial Antenna Using Pearson Kernel-Based Techniques

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Computers, Materials & Continua 2024年第3期78卷 3449-3467页

作者： sherly Alphonse s.Abinaya sourabh paul school of Computer science and engineering Vellore Institute of TechnologyChennai600127India school of electronics engineering Vellore Institute of TechnologyChennai600127India

The use of metamaterial enhances the performance of a specific class of antennas known as metamaterial *** radiation cost and quality factor of the antenna are influenced by the size of the *** antennas allow for the circumvention of the bandwidth restriction for small *** parameters have recently been predicted using machine learning algorithms in existing *** learning can take the place of the manual process of experimenting to find the ideal simulated antenna *** accuracy of the prediction will be primarily dependent on the model that is *** this paper,a novel method for forecasting the bandwidth of the metamaterial antenna is proposed,based on using the Pearson Kernel as a standard *** with these new approaches,this paper suggests a unique hypersphere-based normalization to normalize the values of the dataset attributes and a dimensionality reduction method based on the Pearson kernel to reduce the dimension.A novel algorithm for optimizing the parameters of Convolutional Neural Network(CNN)based on improved Bat Algorithm-based Optimization with Pearson Mutation(BAO-PM)is also presented in this *** prediction results of the proposed work are better when compared to the existing models in the literature.

关键词： Antenna pearson optimization bandwidth metamaterial

Pressurized environments directly influence friction and wear of dry steel contacts—Investigations in a novel high fluid pressure tribometer

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Friction 2024年第7期12卷 1599-1617页

作者： paul ReICHLe Jakob BARZ Georg UMLAUF Günter e.M.TOVAR Institute of Interfacial Process engineering and Plasma Technology(IGVP) University of StuttgartStuttgart 70569Germany Fraunhofer Institute for Interfacial engineering and Biotechnology(IGB) Stuttgart 70569Germany

To reduce the usage of classical lubricants in deep drawing,a new tribological system based on volatile lubricants was ***,a volatile medium is injected under high pressure into the interstice between drawing tool and sheet *** on temperature and pressure,the temporary lubricant may exist in its gaseous or liquid *** this study,a novel high fluid pressure tribometer was designed to investigate the friction and wear of dry steel contacts under comparable conditions like in dry deep ***,a new ball-on-disc tribometer was designed and integrated into a high-pressure *** specifically investigate the effects of different environments(technical air,liquid and gaseous carbon dioxide,nitrogen,argon)at atmospheric and high pressure(0.1 MPa,6 MPa)on tribology,the specimens and all components were operating *** the experiments,the friction was measured *** show that the highest friction occurs in air and the lowest in carbon dioxide *** to the experiments,the wear of the specimens was assessed along with changes in surface chemistry related to tribochemical ***,the tribology of the dry sliding contacts is correlated to changes of the surface *** differences as well as similarities regarding the different fluid environments are *** the results show,the differences between the media used are most pronounced at elevated ***,this work gives clear indications on the suitability of volatile lubricants in dry friction or rather gas lubrication,especially for dry deep drawing.

关键词： dry friction and dry wear gas lubrication carbon dioxide tribo-layer dry metal forming

Application of a simplified ADM1 for full-scale anaerobic co-digestion of cattle slurry and grass silage:assessment of input variability

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Frontiers of environmental science & engineering 2024年第4期18卷 125-139页

作者： sofia Tisocco sören Weinrich Gary Lyons Michael Wills Xinmin Zhan paul Crosson Civil engineering College of Science and EngineeringUniversity of GalwayGalwayH91 TK33Ireland Teagasc Animal and Bioscience Research Department Animal and Grassland Research and Innovation CentreDunsanyC15 PW93Ireland Biochemical Conversion Department Deutsches Biomasseforschungszentrum gemeinnützige GmbHLeipzig 04347Germany Faculty of energy·Building services·environmental engineering Münster University of Applied SciencesSteinfurt 48565Germany Agri-Food and Biosciences Institute HillsboroughBT266DRUK Ryan Institute University of GalwayGalwayH91 TK33Ireland MaReI Research Centre for energy Climate and MarineRyan InstituteUniversity of GalwayGalwayH91 TK33Ireland

Mathematical modeling of anaerobic digestion is a powerful tool to predict gas yields and optimize the *** Anaerobic Digestion Model No.1(ADM1)is a widely implemented model for this ***,modeling full-scale biogas plants is challenging due to the extensive substrate and parameter characterization *** study describes the modification of the ADM1 through a simplification of individual process phases,characteristic components and required ***,the ability of the simplified model to simulate the co-digestion of grass silage and cattle slurry was evaluated using data from a full-scale biogas *** impacts of substrate composition(crude carbohydrate,protein and lipid concentration)and variability of carbohydrate degradability on simulation results were assessed to identify the most influential *** indicated that the simplified version was able to depict biogas and biomethane production with average model efficiencies,according to the Nash-sutcliffe efficiency(Nse)coefficient,of 0.70 and 0.67,respectively,and was comparable to the original ADM1(average model efficiencies of 0.71 and 0.63,respectively).The variability of crude carbohydrate,protein and lipid concentration did not significantly impact biogas and biomethane output for the data sets *** contrast,carbohydrate degradability seemed to explain much more of the variability in the biogas and methane ***,the application of simplified models provides a reliable basis for the process simulation and optimization of full-scale agricultural biogas plants.

关键词： ADM1 Agricultural feedstocks Biogas technology Input variability Parameter estimation

Nonlinear wave dispersion in monoatomic chains with lumped and distributed masses:discrete and continuum models

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Applied Mathematics and Mechanics(english edition) 2024年第4期45卷 633-648页

作者： e.GHAVANLOO s.eL-BORGI school of Mechanical engineering Shiraz UniversityShiraz 71963-16548Iran Mechanical engineering Program Texas A&M University at QatarDoha 23874Qatar

The main objective of this paper is to investigate the influence of inertia of nonlinear springs on the dispersion behavior of discrete monoatomic chains with lumped and distributed *** developed model can represent the wave propagation problem in a non-homogeneous material consisting of heavy inclusions embedded in a *** inclusions are idealized by lumped masses,and the matrix between adjacent inclusions is modeled by a nonlinear spring with distributed ***,the model is capable of depicting the wave propagation in bi-material bars,wherein the first material is represented by a rigid particle and the second one is represented by a nonlinear spring with distributed *** discrete model of the nonlinear monoatomic chain with lumped and distributed masses is first considered,and a closed-form expression of the dispersion relation is obtained by the second-order Lindstedt-Poincare method(LPM).Next,a continuum model for the nonlinear monoatomic chain is derived directly from its discrete lattice model by a suitable continualization *** subsequent use of the second-order method of multiple scales(MMs)facilitates the derivation of the corresponding nonlinear dispersion relation in a closed *** novelties of the present study consist of(i)considering the inertia of nonlinear springs on the dispersion behavior of the discrete mass-spring chains;(ii)developing the second-order LPM for the wave propagation in the discrete chains;and(iii)deriving a continuum model for the nonlinear monoatomic chains with lumped and distributed ***,a parametric study is conducted to examine the effects of the design parameters and the distributed spring mass on the nonlinear dispersion relations and phase velocities obtained from both the discrete and continuum *** parameters include the ratio of the spring mass to the lumped mass,the nonlinear stiffness coefficient of the spring,and the wave amplitude.

关键词： nonlinear mass-spring chain discrete model continuum model LindstedtPoincare method(LPM) method of multiple scales(MMs) dispersion phase velocity

Hypoxic and temporal variation in the endocrine disrupting toxicity of perfluorobutanesulfonate in marine medaka(Oryzias melastigma)

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Journal of environmental sciences 2024年第2期136卷 279-291页

作者： Baili sun Jing Li Yachen Bai Xiangzhen Zhou paul K.s.Lam Lianguo Chen state Key Laboratory of Freshwater ecology and Biotechnology Institute of HydrobiologyChinese Academy of SciencesWuhan 430072China University of Chinese Academy of sciences Beijing 100049China Office of the President Hong Kong Metropolitan University30 Good Shepherd StreetKowloonHong Kong SARChina

Perfluorobutanesulfonate(PFBs)is an emerging pollutant capable of potently disrupting the sex and thyroid endocrine systems of ***,the hypoxic and temporal variation in PFBs endocrine disrupting toxicity remain largely *** the present study,adult marine medaka were exposed to environmentally realistic concentrations of PFBs(0 and 10μg/L)under normoxia or hypoxia conditions for 7 days,aiming to explore the interactive behavior between PFBs and *** addition,PFBs singular exposure was extended till 21days under normoxia to elucidate the time-course progression in PFBs *** results showed that hypoxia inhibited the growth and caused the suspension of egg spawn regardless of PFBs *** regard to the sex endocrine system,7-day PFBs exposure led to an acute stimulation of transcriptional profiles in females,which,subsequently,recovered after the 21-day *** potency of hypoxia to disturb the sex hormones was much stronger than PFBs.A remarkable increase in estradiol concentration was noted in medaka blood after hypoxia *** in sex endocrinology of coexposed fish were largely determined by hypoxia,which drove the formation of an estrogenic *** further enhanced the endocrine disrupting effects of ***,the hepatic synthesis of vitellogenin and choriogenin,two commonly used sensitive biomarkers of estrogenic activity,failed to initiate in response to the estrogen *** to sex endocrine system,disturbances in thyroidal axis by PFBs or hypoxia were relatively ***,the present findings will advance our toxicological understanding about PFBs pollutant under the interference of hypoxia.

关键词： Perfluorobutanesulfonate(PFBs) Aquatic hypoxia Temporal toxicity Combined exposure endocrine disruption Marine medaka

evaluation of the seismic behavior of reinforced concrete structures with flat slab-column gravity frame and shear walls through nonlinear analysis methods

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earthquake engineering and engineering Vibration 2024年第3期23卷 713-726页

作者： M.A.Najafgholipour s.Heidarian Radbakhsh e.erfani Department of Civil and environmental engineering Shiraz University of TechnologyShiraz ***Iran Department of Building Civiland Environmental EngineeringConcordia UniversityMontréal H3G 1M8Canada

This paper presents an investigation of the seismic behavior of reinforced concrete(RC)structures in which shear walls are the main lateral load-resisting elements and the participation of flat slab floor systems is not considered in the seismic design *** this regard,the behavior of six prototype structures(with different heights and plan layouts)is investigated through nonlinear static and time history analyses,implemented in the Opensees *** results of the analyses are presented in terms of the behavior of the slab-column connections and their mode of failure at different loading ***,the global response of the buildings is discussed in terms of some parameters,such as lateral overstrength due to the gravity flat slab-column *** to the nonlinear static analyses,in structures in which the slab-column connections were designed only for gravity loads,the slab-column connections exhibited a punching mode of failure even in the early stages of ***,the punching failure was eliminated in structures in which a minimum transverse reinforcement recommended in ACI 318(2019)was provided in the slabs at joint ***,despite neglecting the contribution of gravity flat slab-column frames in the lateral load resistance of the structures,a relatively significant overstrength was imposed on the structures by the gravity frames.

关键词： RC flat slab-column frames seismic behavior nonlinear analysis time history analysis

emission colour tuning in KLnF_(4):Yb^(3+),er^(3+)/Ho^(3+)phosphor

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Journal of Rare earths 2024年第1期42卷 57-65,I0002页

作者： Janani K Gayathri e Vijayatha V Ramasubramanian s Thiyagarajan P Department of science and Humanities Nehru Institute of TechnologyKaliapuramThirumalayampalayamCoimbatoreIndia Department of sciences Amrita School of Physical SciencesAmrita Vishwa VidyapeethamCoimbatoreIndia Department of Physics Anna UniversityChennaiIndia

KLnF_(4):Yb^(3+),er^(3+)/Ho^(3+)(Ln=Y,Yb,Gd)phosphors were prepared by solid-state reaction *** each of the Yb^(3+)/er^(3+)and Yb^(3+)/Ho^(3+)co-doped phosphors independently,phase confirmation and morphological examination were accomplished using the X-ray diffraction technique and scanning electron microscope analysis.X-ray photoelectron spectroscopy analysis shows the charge state and existence of lanthanides and *** luminescence emissions of green and red colour were detected for the synthesized *** changes in the upconverted emission intensities and colour output pertaining to the change of the lanthanide host matrix along with dopants were investigated for the prepared *** the upconversion luminescence,erbium-doped samples exhibit a predominance of red emission while holmium-doped samples display a prevalence of green *** rare-earth er/Ho doped KYbF4shows strong red emission compared to other ***_(4):Yb,er/Ho exhibits relatively significant green upconve rsion emissions,while Yb,er-doped KGdF_(4)host displays a 10-fold increase in green/red emission ratio with an increase in the input power of 20-780 *** photoluminescence studies and decay curve analysis were carried out using UV light excitation for the developed phosphors.A higher lifetime of 2.2 ms was measured for the downshifting red emission in the Ho doped KYbF_(4)*** study suggests a potential for colour tunability in the upconversion and downshifting emissions through host modifications to the fluoride phosphor.

关键词： Rare earths energy transfer upconversion Downshifting Colour coordinates

Adipose-derived regenerative therapies for the treatment of knee osteoarthritis

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World Journal of stem Cells 2024年第4期16卷 324-333页

作者： Ilias e epanomeritakis Wasim s Khan Division of Trauma and Orthopaedic surgery Addenbrooke’s HospitalCambridge University Hospitals NHS Foundation TrustCambridge CB20QQUnited Kingdom Division of Trauma and Orthopaedic surgery Department of SurgeryUniversity of CambridgeCambridge CB20QQUnited Kingdom

Knee osteoarthritis is a degenerative condition with a significant disease burden and no disease-modifying *** treatment ultimately requires joint *** capable of regenerating cartilage could significantly reduce financial and clinical *** regenerative potential of mesenchymal stromal cells(MsCs)has been extensively studied in the context of knee *** has yielded promising results in human studies,and is likely a product of immunomodulatory and chondroprotective biomolecules produced by MsCs in response to ***-derived MsCs(AsCs)are becoming increasingly popular owing to their relative ease of isolation and high proliferative *** vascular fraction(sVF)and micro-fragmented adipose tissue(MFAT)are produced by the enzymatic and mechanical disruption of adipose tissue,*** avoids expansion of isolated AsCs ex vivo and their composition of heterogeneous cell populations,including immune cells,may potentiate the reparative function of *** this editorial,we comment on a multicenter randomized trial regarding the efficacy of MFAT in treating knee *** discuss the study’s findings in the context of emerging evidence regarding adipose-derived regenerative *** underlying mechanism of action of AsCs is proposed while drawing important distinctions between the properties of isolated AsCs,sVF,and MFAT.

关键词： Knee osteoarthritis Mesenchymal stromal cells Adipose tissue stromal vascular fraction Micro-fragmented adipose tissue Regeneration

Advanced strategies for marine antifouling based on nanomaterial-enhanced functional PDMs coatings

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Nano Materials science 2024年第4期6卷 375-395页

作者： Xiaohui shi Hao Wei Wenjun Zhou paul e.D.soto Rodriguez Cunguo Lin Lei Wang Zhijia Zhang school of Materials science and Chemical engineering Harbin Engineering University Qingdao Innovation and Development Center of Harbin engineering University state Key Laboratory for Marin Corrosion and Protection Luoyang Ship Material Research Institute (LSMRI) Instituto de estudios Avanzados IUDeA Departamento de Física Universidad de La Laguna C/Astrofísico Francisco Sanchez school of Chemistry and Chemical engineering Harbin Institute of Technology

Marine biofouling seriously affects human marine exploitation and transportation activities, to which marine antifouling(AF) coatings are considered to be the most cost-effective solution. since the mid-20th century, human beings have dedicated their efforts on developing AF coatings with long cycle and high performance, leading to a large number of non-target organisms? distortion, death and marine environmental pollution. Polydimethylsiloxane(PDMs), is considered as one of the representative environment-friendly AF materials thanks to its non-toxic, hydrophobic, low surface energy and AF properties. However, PDMs AF coatings are prone to mechanical damage, weak adhesion strength to substrate, and poor static AF effect, which seriously restrict their use in the ocean. The rapid development of various nanomaterials provides an opportunity to enhance and improve the mechanical properties and antifouling properties of PDMs coating by embedding *** on our research background and the problems faced in our laboratory, this article presents an overview of the current progress in the fields of PDMs composite coatings enhanced by different nanomaterials, with the discussion focused on the advantages and main bottlenecks currently encountered in this field. Finally, we propose an outlook, hoping to provide fundamental guidance for the development of marine AF field.

关键词： Nanomaterials Antifouling PDMs composites environment-friendly Marine biofouling