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Free vibration and buckling analysis of polymeric composite beams reinforced by functionally graded bamboo fbers

Applied Mathematics and Mechanics(English Edition) 2024年第3期45卷 543-562页

作者： h.M.FEIZABAD M.h.YAS Department of Mechanical Engineering Razi UniversityKermanshah ***Iran

Natural fibers have been extensively researched as reinforcement materials in polymers on account of their environmental and economic advantages in comparison with synthetic fibers in the recent *** fibers are renowned for their good mechanical properties,abundance,and short cycle *** beams are one of the fundamental structural components and are susceptible to mechanical loads in engineering applications,this paper performs a study on the free vibration and buckling responses of bamboo fiber reinforced composite(BFRC)beams on the elastic *** different functionally graded(FG)layouts and a uniform one are the considered distributions for unidirectional long bamboo fibers across the *** elastic properties of the composite are determined with the law of *** hamilton’s principle,the governing equations of motion are *** generalized differential quadrature method(GDQM)is then applied to the equations to obtain the *** achieved outcomes exhibit that the natural frequency and buckling load values vary as the fiber volume fractions and distributions,elastic foundation stiffness values,and boundary conditions(BCs)and slenderness ratio of the beam ***,a comparative study is conducted between the derived analysis outcomes for BFRC and homogenous polymer beams to examine the effectiveness of bamboo fibers as reinforcement materials,demonstrating the significant enhancements in both vibration and buckling responses,with the exception of natural frequencies for cantilever beams on the Pasternak foundation with the FG-◇fiber ***,the obtained analysis results of BFRC beams are also compared with those for carbon nanotube reinforced composite(CNTRC)beams found in the literature,indicating that the buckling loads and natural frequencies of BFRC beams are lower than those of CNTRC beams.

关键词： bamboo fiber free vibration buckling analysis functionally graded(FG)beam elastic foundation generalized differential quadrature method(GDQM)

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Nonuniform Dependence on the Initial Data for Solutions of Conservation Laws

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Communications on Applied Mathematics and Computation 2024年第1期6卷 489-500页

作者： john M.holmes Barbara Lee Keyfitz Department of Mathematics The Ohio State UniversityColumbusOH43210USA

In this paper,we study systems of conservation laws in one space *** prove that for classical solutions in Sobolev spaces h^(s),with s>3/2,the data-to-solution map is not uniformly *** results apply to all nonlinear s... 详细信息

关键词： Conservation laws Data-to-solution map Nonuniform dependence

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What Knowledge is of Most Worth?Considering the Neo-Confucians in the Contemporary Debate Between Moral and Intellectual Learning

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ECNU Review of Education 2024年第1期7卷 155-163页

作者： john Patrick Shekitka Manhattanville College

●The perennial debate regarding the relative usefulness of various forms of knowledge,especially between the theoretical and practical and the intellectual and moral,lies at the heart of education in both past and present times in both the West and China(de Bary,1988,2004,2005,2015).●Neo-Confucians remain relevant in the 21st century and can help us to understand and elucidate contemporary debates in education-specifically,to answer the question Spencer asked nearly a century and a half ago:"What knowledge is of most worth?".●Mencius,Zhu Xi,Wang Yangming,Xu Ai,and Kang Youwei advocated for a type of learning that would strongly resonate with john Dewey(1938)and Paulo Freire(1970,1978).Foundational philosophies of education,particularly in the United States,have drawn heavily on 20th century European-American thinkers;this article attempts to correct this myopia and broaden perspectives.

关键词： Freire john Dewey Neo-Confucian

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Optimizing prediction models for pancreatic fistula after pancreatectomy:Current status and future perspectives

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World Journal of Gastroenterology 2024年第10期30卷 1329-1345页

作者： Feng Yang john A Windsor De-Liang Fu Department of Pancreatic Surgery Huashan HospitalShanghai Medical CollegeFudan UniversityShanghai 200040China Surgical and Translational Research Centre Faculty of Medical and Health SciencesUniversity of AucklandAuckland 1142New Zealand

Postoperative pancreatic fistula(POPF)is a frequent complication after pancre-atectomy,leading to increased morbidity and *** prediction models for POPF has emerged as a critical focus in surgical *** over sixty models following pancreaticoduodenectomy,predominantly reliant on a variety of clinical,surgical,and radiological parameters,have been documented,their predictive accuracy remains suboptimal in external validation and across diverse *** models after distal pancreatectomy continue to be pro-gressively reported,their external validation is eagerly ***,POPF prediction after central pancreatectomy is in its nascent stage,warranting urgent need for further development and *** potential of machine learning and big data analytics offers promising prospects for enhancing the accuracy of prediction models by incorporating an extensive array of variables and optimizing algorithm ***,there is potential for the development of personalized prediction models based on patient-or pancreas-specific factors and postoperative serum or drain fluid biomarkers to improve accuracy in identifying individuals at risk of *** the future,prospective multicenter studies and the integration of novel imaging technologies,such as artificial intelligence-based radiomics,may further refine predictive *** these issues is anticipated to revolutionize risk stratification,clinical decision-making,and postoperative management in patients undergoing pancre-atectomy.

关键词： Pancreatic fistula Pancreaticoduodenectomy Distal pancreatectomy Central pancreatectomy Prediction model Machine learning Artificial intelligence

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Characteristics and Preliminary Causes of Tropical Cyclone Remote Precipitation over China

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Journal of Ocean University of China 2024年第4期23卷 845-858页

作者： JIA Li REN Fumin MCBRIDE john Leonard CONG Chunhua School of Atmospheric Science Nanjing University of Information Science and TechnologyNanjing 210044China State Key Laboratory of Severe Weather Chinese Academy of Meteorological SciencesBeijing 100081China School of Earth Science University of MelbourneMelbourne 3052Australia Research and Development Division Bureau of MeteorologyMelbourne 3052Australia Shandong Meteorological Bureau Jinan 250031China

In this study,the characteristics and preliminary causes of tropical cyclone remote precipitation(TRP)over China during the period from 1979 to 2020 are *** indicated that approximately 72.42%of tropical cyclones(TCs)in the Western Pacific produce TRP over *** peak months for TRP are July and *** four key regions of TRP are the adjacent areas between the Sichuan and Shaanxi Provinces,the northern coast of the Bohai Sea,the coast of the Yellow Sea,and the southern coast *** typical distance between the station with TRP and the TC center ranges from 1500 to 2500 *** of these stations are situated north to 60°west of north of the *** south–west water vapor transportation on the west side of the TC is crucial to *** has a decreasing trend because of the decrease in the number of TCs that generate *** the perspective of large-scale environmental conditions,a decrease in the integrated horizontal water vapor transport in China' Mainland,the weakening of upward motion at approximately 25°–35°N,which is inconducive to convection,and an increase in low-level vertical wind shear,which is unfavorable for the development of TC in areas with high frequencies of TRP-related TCs,are the factors that result in the decreasing trend of TRP.

关键词： tropical cyclone remote precipitation characteristics causes

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Interfacial friction induced capillary flow within nanofiber-supported ionic liquid droplets

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Green Energy & Environment 2024年第5期9卷 789-791页

作者： Yuanyuan Zhao Gang Xia Yintung Lam john haozhong Xin School of Fashion and Textiles The Hong Kong Polytechnic UniversityHong KongChina Shenzhen Research Institute The Hong Kong Polytechnic UniversityShenzhenChina

As global economic growth increases,the demand for energy sources *** fossil fuels have traditionally satisﬁed this demand,their environmental inﬂuence and limited reserves require *** fuel combustion contributes substantially to greenhouse gas emissions,with a pressing need to halve these emissions by 2030 and target net-zero by *** energy sources,contributing currently to 29%of global electricity,are viewed as promising *** wind energy's potential,Zheng's team developed a novel method to harness even low wind speeds using well-aligned nanoﬁbers and an innovative“drop wind generator”.This system,combining moisture-saturated ionic liquid 3-Methyl-1-octylimidazolium chloride with speciﬁc nanoﬁber arrays,exploits wind-inducedﬂows for energy *** study highlights the vast untapped potential of low-speed wind as a sustainable energy source potentially for electronics.

关键词： Wind energy Low-speed wind Ionic liquid Electronic devices

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holographic dark energy in non-conserved gravity theory

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Communications in Theoretical Physics 2024年第4期76卷 126-133页

作者： h R Fazlollahi Institute of Gravitation and Cosmology Peoples Friendship University of Russia(RUDN University)6 Miklukho-Maklaya StMoscow117198Russia

Recently, reconsidering the Rastall idea T_(μ;νν)^(v)=α_(,μ) through relativistic thermodynamics gives a new form for the scalar field α which led us to construct modern modified theory of gravity debugged ‘non-conserved gravity theory’ Fazlollahi 2023 Euro. Phys. J. C 83 923. This theory unlike other modified theories of gravity cannot directly explain the current acceleration expansion in the absence of the cosmological constant and or existence of other forms of dark energy. hence, in this study we have reinvestigated holographic dark energy Ρ_(X)~h^(2) in the non-conserved theory of gravity. In this context, the density and pressure of dark energy depend on the non-conserved term and density of the dust matter field. As shown, due to non-conservation effects on large-scale structures, unlike the original holographic model, our model onsets an acceleration epoch for the current Universe satisfies observations. Moreover, the interaction and viscous scenarios are studied for this model.

关键词： non-conserved gravity covariant form of thermodynamics holographic dark energy

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Novel synthesis of stabilized Bi1-x-yGdxDyyO1.5 solid electrolytes with enhanced conductivity for intermediate temperature solid oxide fuel cells（SOFCs）

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Journal of Rare Earths 2024年第10期42卷 1903-1911页

作者： Ahmed h.Ibrahim Yehia M.Abbas h.A.Ayoub Marwa h.Ali Mustafa Aldoori Materials Science Laboratory Physics DepartmentFaculty of ScienceSuez Canal University Ministry of higher Education and Scientific Research Aliraqia University

herein,we report the synthesis of a Dy-Gd co-doped cubic phase-stabilized Bi2O3solid electrolyte system via solid-state processing under atmospheric *** with Dy3+and Gd3+has been observed to significantly enhance the densification process during sintering for stabilization purposes,thereby improving the electrical properties of δ-Bi2O3-type *** synthesized ceramics were characterized using X-ray diffraction（XRD）,field emission scanning electron microscopy-energy dispersive X-ray spectroscopy（FESEM-EDX）,thermal gravimetry/differential thermal analysis（TG/DTA）,and the four-point probe technique（4PPT）.XRD analysis reveals that the samples Bi1-x-yGdxDyyO1.5（y=0.05/x=0.05,0.10,0,15,and 0.20,and x=0.05/y=0.10,0.15,and 0.20） exhibit a stable face-centered cubic δ-phase and a mixed-phase crystallographic *** XRD analysis of the stabilized δ-phase suggests that the prepared oxides show a face-centered cubic（FCC） structure with a space group of *** micrographs reveal that the composition Bi0.90Gd0.05Dy0.05O1.5has no significant ***,an evident increase in the pore formation is observed as the amount of Gd2O3increases until it reaches 20%.This finding suggests that dense pellets are formed during the sintering process at 900-1000℃.The DTA analyses were performed to verify the phase stability,which agrees with the XRD *** electrochemical performance of the synthesized Dy-Gd co-doped Bi2O3solid electrolyte system was evaluated and analyzed in detail by using the electrochemical impedance spectroscopy（EIS） technique,Based on EIS and conductivity measurements,Bi0.75Gd0.20Dy0.05O1.5exhibits the lowest activation energy of 0.519 eV and the highest conductivity value of 0.398 S/cm at 627℃compared to the other samples;this composition can be used as a solid electrolyte for intermediatetemperature solid oxide fuel cells（SOFCs）.

关键词： Electrochemical impedance spectroscopy (EIS) Fast Fourier transform (FFT) Rare earths Rietveld Solid oxide fuel cells (SOFCs) Solid-state processing

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Mg/MgO interfaces as efficient hydrogen evolution cathodes causing accelerated corrosion of additive manufactured Mg alloys:A DFT analysis

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Journal of Magnesium and Alloys 2024年第1期12卷 110-119页

作者： Man-Fai Ng Kai Xiang Kuah Teck Leong Tan Daniel john Blackwood Department of Materials Science&Engineering National University of Singapore9 Engineering Drive 1Singapore 117575Republic of Singapore Institute of high Performance Computing(IhPC) Agency for ScienceTechnology and Research(A∗STAR)1 Fusionopolis Way#16-16 ConnexisSingapore 138632Republic of Singapore

The corrosion rates of additive-manufactured Mg alloys are higher than their as-cast counterparts,possibly due to increased kinetics for the hydrogen evolution reaction on secondary phases,which may include oxide *** Kelvin Probe Force Microscopy demonstrated that MgO inclusions could act as cathodes for Mg corrosion,but their low conductivity likely precludes ***,the density of state calculations through density functional theory using hybrid hSE06 functional revealed overlapping electronic states at the Mg/MgO interface,which facilitates electron transfers and participates in redox *** determination of the hydrogen absorption energy at the Mg/MgO interface reveals it to be an excellent catalytic site,with hER being found to be a factor of 23x more efficient at the interface than on metallic *** results not only support the plausibility of the Mg/MgO interface being an effective cathode to the adjacent anodic Mg matrix during corrosion but also contribute to the understanding of the enhanced cathodic activities observed during the anodic dissolution of magnesium.

关键词： Magnesium Magnesium oxide Interface hydrogen evolution DFT

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Convexification of hybrid AC-DC Optimal Power Flow with Line-Commutated Converters

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CSEE Journal of Power and Energy Systems 2024年第2期10卷 617-628页

作者： hongyuan Liang Zhigang Li J.h.Zheng Q.h.Wu School of Electric Power Engineering South China University of TechnologyGuangzhou 510641China

Line-commutated converter (LCC)-based high-voltage DC (hVDC) systems have been integrated with bulk AC power grids for interregional transmission of renewable power. The nonlinear LCC model brings additional nonconvexity to optimal power flow (OPF) of hybrid AC-DC power grids. A convexification method for the LCC station model could address such nonconvexity but has rarely been discussed. We devise an equivalent reformulation for classical LCC station models that facilitates second-order cone convex relaxation for the OPF of LCC-based AC-DC power grids. We also propose sufficient conditions for exactness of convex relaxation with its proof. Equivalence of the proposed LCC station models and properties, exactness, and effectiveness of convex relaxation are verified using four numerical simulations. Simulation results demonstrate a globally optimal solution of the original OPF can be efficiently obtained from relaxed model.

关键词： AC-DC power system convex relaxation linecommutated converter optimal power flow second-order cone programming

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