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Effect of divalent cations(Co^(2+) and Ni^(2+)) on microstructure,physical properties and application of NdFeO_(3)

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Journal of Rare Earths 2025年第1期43卷 89-97,I0004页

作者： m.m.Arman materials Science Lab(1) Physics DepartmentFaculty of ScienceCairo UniversityGiza12613Egypt

The nanocrystalline samples Nd_(1-x)m_(x)FeO_(3)(x=0.0 and 0.1;m:Co^(2+)and Ni^(2+))were prepared using the citrate combustion *** X-ray diffraction(XRD)pattern confirmed that the nanoparticles were synthesized in an orthorhombic *** particle size of Nd_(1-x)m_(x)FeO_(3) is in the range of 29-59 *** selected area electron diffraction(SAED)indicates the samples were prepared in a polycrystalline *** samples Nd_(1-x)m_(x)FeO_(3)(x=0.0 and 0.1;m:Co^(2+)and Ni^(2+))have anti ferromagnetic *** Fe^(3+)spins are aligned antiparallel,forming the antiferromagnetic(AFm)properties,which are affected by many factors such as the bond angle between the Fe^(3+)(Fe^(3+)-O_(2)--Fe^(3+))and the Dzyaloshinskii-moriya(D-m)*** doping of Co^(2+)and Ni^(2+)ions in NdFeO_(3) enhances the magnetic properties of the NdFeO_(3).The saturation magnetization(ms)of Nd_(0.90)Co_(0.10)FeO_(3) increases 1.8times more than that of NdFeO_(3).The exchange bias field(HEX)of the Co-doped sample is two times greater than that of NdFeO_(3).The magnetic anisotropy constant(K)of the 10%Co-doped sample increases by 11 factors compared to that of NdFeO_(3).The Tauc plot illustrates that the samples have a direct optical *** divalent cation substitution(Co^(2+)and Ni^(2+))decreases the optical band gap of NdFeO_(3),leading to the recommendation of using the samples Nd_(0.90)Co_(0.10)FeO_(3) and Nd_(0.90)Ni_(0.10)FeO_(3) in photocatalysis of dye degradation from *** removal efficiencies of Cr6+at pH=6 are 88.06%,85.54%,and 85.52%for the samples NdFeO_(3),Nd_(0.90)Co_(0.10)FeO_(3),and Nd_(0.90)Ni_(0.10)FeO_(3),*** Freundlich isotherm mode is the best-fit model for NdFeO_(3) to adsorb Cr6+ions from aqueous solutions.

关键词： Optical properties Nanoparticles magnetic properties Perovskites Removal efficiency Rareearths

Nonlinear forced vibration in a subcritical reg.m. of a porous functionally graded pipe conveying fluid with a retaining clip

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Applied mathematics and mechanics(English Edition) 2025年第1期46卷 101-122页

作者： m.gHOLAmI m.EFTEKHARI Department of mechanical Engineering Shahid Bahonar University of Kerman

This study examines the nonlinear behaviors of a clamped-clamped porous pipe made of a functionally graded material(Fgm) that conveys fluids and is equipped with a retaining clip, focusing on primary resonance and subcritical dynamics. The nonlinear governing equations for the Fgm pipe are derived by the extended Hamilton's principle, and subsequently discretized through the application of the galerkin *** direct method of multi-scales is then used to solve the derived equations. A thorough analysis of various parameters, including the clip stiffness, the power-law index, the porosity, and the clip location, is conducted to gain a comprehensive understanding of the system's nonlinear dynamics. Through the analysis of the first natural frequency, the study highlights the influence of the flow velocity and the clip stiffness, while the comparisons with metallic pipes emphasize the role of Fgm composition. The examination of the forced response curves reveals saddle-node bifurcations and their dependence on parameters such as the detuning parameter and the power-law index, offering valuable insights into the system's nonlinear resonant behavior. Furthermore, the frequency-response curves illustrate the hardening nonlinearities influenced by factors such as the porosity and the clip stiffness, revealing nuanced effects on the system response and resonance characteristics. This comprehensive analysis enhances the understanding of nonlinear behaviors in Fgm porous pipes with a retaining clip, providing key insights for practical engineering applications in system design and optimization.

关键词： functionally graded material (Fgm) pipe conveying fluid O175.2 porosity primary resonance retaining clip subcritical reg.m.

Honeycomb-spiderweb-inspired self-similar hybrid cellular structures for impact applications

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Defence Technology(防务技术) 2025年第1期43卷 182-200页

作者： K.Tewari m.K.Pandit m.m.mahapatra P.R.Budarapu School of mechanical Sciences Indian Institute of Technology BhubaneswarBhubaneswar752050India

Inspired by nature's self-similar designs,novel honeycomb-spiderweb based self-similar hybrid cellular structures are proposed here for efficient energy absorption in impact *** energy absorption is enhanced by optimizing the geometry and topology for a given *** proposed hybrid cellular structure is arrived after a thorough analysis of topologically enhanced self-similar *** optimized cell designs are rigorously tested considering dynamic loads involving crush and high-velocity bullet ***,the influence of thickness,radial connectivity,and order of patterning at the unit cell level are also *** maximum crushing efficiency attained is found to be more than 95%,which is significantly higher than most existing traditional *** on,the first and second-order hierarchical self-similar unit cell designs developed during crush analysis are used to prepare the cores for sandwich *** tests are performed on the developed sandwich structures using the standard 9-mm *** influence of multistaging on impact resistance is also investigated by maintaining a constant total thickness and mass of the sandwich ***,in order to avoid layer-wise weak zones and hence,attain a uniform out-of-plane impact strength,off-setting the designs in each stage is *** sandwich structures with first and second-order self-similar hybrid cores are observed to withstand impact velocities as high as 170 m/s and 270 m/s,respectively.

关键词： Sandwich structures Honeycomb-spider web inspired Self-similar hierarchy Crush analysis High-velocity impact Strong and weak zones multistaging

Discovering causal models for structural,construction and defense-related engineering phenomena

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Defence Technology(防务技术) 2025年第1期43卷 60-79页

作者： m.Z.Naser School of Civil&Environmental Engineering and Earth Sciences(SCEEES) Clemson UniversityClemsonSouth Carolina 29634USA The Artificial Intelligence Research Institute for Science and Engineering(AIRISE) Clemson UniversityClemsonSouth Carolina 29634USA

Causality,the science of cause and effect,has made it possible to create a new family of *** models are often referred to as causal *** those of mathematical,numerical,empirical,or machine learning.m.)nature,causal models hope to tie the cause(s)to the effect(s)pertaining to a phenomenon(i.e.,data generating process)through causal *** paper presents one of the first works at creating causal models in the area of structural and construction *** this end,this paper starts with a brief review of the principles of causality and then adopts four causal discovery algorithms,namely,PC(Peter-Clark),FCI(fast causal inference),gES(greedy equivalence search),and gRa SP(greedy relaxation of the sparsest permutation),have been used to examine four phenomena,including predicting the load-bearing capacity of axially loaded members,fire resistance of structural members,shear strength of beams,and resistance of walls against impulsive(blast)*** from this study reveal the possibility and merit of discovering complete and partial causal ***,this study also proposes two simple metrics that can help assess the performance of causal discovery algorithms.

关键词： Causality Causal discovery Directed acyclic graphs machine learning metrics

Transport mechanism in chemically reactive hybrid nanofluid flow containing gyrotactic micro-organisms over a curved oscillatory surface

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Applied mathematics and mechanics(English Edition) 2025年第1期46卷 177-192页

作者： m.NAVEED m.ImRAN T.ASgHAR Z.ABBAS Department of mathematics Division of Science and TechnologyUniversity of Education Department of mathematics The Islamia University of Bahawalpur

This paper examines the transport analysis, including both heat transfer and mass transfer, in hybrid nanofluid flow containing gyrotactic microorganisms towards a curved oscillatory surface. The influence of magnetic fields is also inspected in terms of their physical characteristics. To depict the phenomena of transport, modified versions of both Fick's and Fourier's laws are used. Additionally, the characteristics of both heterogeneous and homogeneous chemical reactions are also incorporated. Utilizing a curvilinear coordinate system, the flow problem is formulated as partial differential equations(PDEs)for momentum, concentration, microorganism field, and energy. An analytical solution to the obtained flow equations is achieved utilizing the homotopy analysis method(HAm).The effects of significant flow parameters on the pressure and microorganism fields, velocity, oscillation velocity, concentration, and temperature distributions are shown via graphs. Furthermore, the variations in skin friction, mass transfer rate, heat transfer rate, and local motile number due to different involved parameters are presented in tables and are analyzed in detail. graphical results indicate that the curves of velocity and temperature fields are enhanced as the values of the solid volume fraction variables *** is also verified that the concentration rate field decreases as the values of the homogeneous reaction strength parameter and the radius of curvature parameter increase, and it increases with the Schmidt number and the heterogeneous reaction strength *** outcomes show a favorable response of the motile number to advanced values of the Peclet number, the Schmidt number, the microorganism difference parameter, and the bio-convective Lewis number.

关键词： analytical solution Cattaneo-Christov heat and mass flux chemical reaction gyrotactic microorganism hybrid nanofluid O368 oscillating curved stretchable sheet

Regression analysis of squeezing-induced hybrid nanofluid flow in Darcy-Forchheimer porous medium

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Applied mathematics and mechanics(English Edition) 2025年第1期46卷 193-208页

作者： K.mUHAmmAD m.SARFRAZ Department of Humanities and Sciences School of Electrical Engineering and Computer Science National University of Sciences and Technology Department of mathematics Quaid-i-Azam University

This article presents a mathematical model addressing a scenario involving a hybrid nanofluid flow between two infinite parallel plates. One plate remains stationary, while the other moves downward at a squeezing velocity. The space between these plates contains a Darcy-Forchheimer porous medium. A mixture of water-based fluid with gold(Au) and silicon dioxide(Si O2) nanoparticles is formulated. In contrast to the conventional Fourier's heat flux equation, this study employs the Cattaneo-Christov heat flux equation. A uniform magnetic field is applied perpendicular to the flow direction, invoking.m.gnetohydrodynamic(mHD) effects. Further, the model accounts for Joule heating, which is the heat generated when an electric current passes through the fluid. The problem is solved via NDSolve in mATHEmATICA. Numerical and statistical analyses are conducted to provide insights into the behavior of the nanomaterials between the parallel plates with respect to the flow, energy transport, and skin *** findings of this study have potential applications in enhancing cooling systems and optimizing thermal manag.m.nt strategies. It is observed that the squeezing.m.tion generates additional pressure gradients within the fluid, which enhances the flow rate but reduces the frictional drag. Consequently, the fluid is pushed more vigorously between the plates, increasing the flow velocity. As the fluid experiences higher flow rates due to the increased squeezing effect, it spends less time in the region between the plates. The thermal relaxation, however, abruptly changes the temperature, leading to a decrease in the temperature fluctuations.

关键词： convective boundary condition Darcy-Forchheimer medium hybrid nanofluid Joule heating magnetohydrodynamic (mHD) numerical solution O175.2 O361 regression analysis squeezing flow

Perspectives on the m 7.1 2025 Southern Tibetan Plateau (Xizang) Earthquake

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Journal of Earth Science 2025年

作者： Timothy m.Kusky Jiannan meng State Key Lab for geological Processes and mineral Resources and Center for Global TectonicsSchool of Earth SciencesChina University of Geosciences(Wuhan) Badong National Observatory and Research Station for geohazards China University of Geosciences

On January 7,2025,01:05:15 UTC （9:05 *** time） southern Tibet was rocked by a mw7.1 earthquake （mw=moment magnitude,USgS） centered（28.639°N 87.361°E） in the Lhasa Block north of the India/Eurasia Plate boundary,in a remote area about 180km SW of Xigaze,in Dingri County of Shigatse of the Xizang Autonomous Region （Figure 1）.The China Earthquake Networks Center measured the magnitude differently,using surface wave magnitude,ms,at *** of Jan.10,a total of 126 people were confirmed dead,another 188 injured,and about 61 500 people displaced from their *** region is currently being shaken by thousands of aftershocks,which are likely to continue for weeks or *** than 14 000 search and rescue personnel have been deployed to the epicentral region.

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Neurogenesis dynamics in the olfactory bulb:deciphering circuitry organization, function, and adaptive plasticity

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Neural Regeneration Research 2025年第6期20卷 1565-1581页

作者： moawiah m.Naffaa Department of Psychology and Neuroscience Duke UniversityDurhamNCUSA Department of Cell Biology Duke University School of MedicineDurhamNCUSA

Adult neurogenesis persists after birth in the subventricular zone, with new neurons migrating to the granule cell layer and glomerular layers of the olfactory bulb, where they integrate into existing circuitry as inhibitory interneurons. The generation of these new neurons in the olfactory bulb supports both structural and functional plasticity, aiding in circuit remodeling triggered by memory and learning processes. However, the presence of these neurons, coupled with the cellular diversity within the olfactory bulb, presents an ongoing challenge in understanding its network organization and function. moreover,the continuous integration of new neurons in the olfactory bulb plays a pivotal role in regulating olfactory information processing. This adaptive process responds to changes in epithelial composition and contributes to the formation of olfactory memories by modulating cellular connectivity within the olfactory bulb and interacting intricately with higher-order brain regions. The role of adult neurogenesis in olfactory bulb functions remains a topic of debate. Nevertheless, the functionality of the olfactory bulb is intricately linked to the organization of granule cells around mitral and tufted cells. This organizational pattern significantly impacts output, network behavior, and synaptic plasticity, which are crucial for olfactory perception and memory. Additionally, this organization is further shaped by axon terminals originating from cortical and subcortical regions. Despite the crucial role of olfactory bulb in brain functions and behaviors related to olfaction, these complex and highly interconnected processes have not been comprehensively studied as a whole. Therefore, this manuscript aims to discuss our current understanding and explore how neural plasticity and olfactory neurogenesis contribute to enhancing the adaptability of the olfactory system. These mechanisms are thought to support olfactory learning and memory, potentially through increased

关键词： network adaptability neurogenesis neuronal communication olfactory bulb olfactory learning olfactory memory synaptic plasticity

Alkaline igneous rocks,a potential source of rare metals and radioactive minerals:Case study at Amreit area,south Eastern Desert,Egypt

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Acta geochimica 2025年第1期44卷 189-214页

作者： Baaha m.Emad Nuclear materials Authority El MaadiP.O.Box:530CairoEgypt

Alkaline igneous rocks represent one of the most economically important resources of radioactive minerals and rare *** field observations and petrographic studies are integrated with whole-rock geochemical analyses and g.m.a ray spectroscopy data of alkaline rocks associated with the Amreit *** fieldwork was achieved by the collection of more than forty samples from alkaline granites and alkaline *** youngest rocks cropping out in the study area are the cogenetic alkaline rocks,ranging from alkaline granite to alkaline *** alkaline rocks are composed essentially of K-feldspar,alkali amphiboles(arfvedsonite),and sodic pyroxene,with accessories such as zircon,apatite,and *** characterization of the highly radioactive zones in both alkaline granite and alkaline syenite displays enrichment in monazite,thorite,zircon,ferro-columbite,xenotime,and allanite *** analyses indicate that the Amreit rocks are alkaline with peralkaline affinity and have high concentrations of total alkalis(K_(2)O+Na_(2)O),large ion lithophile elements(LILEs;Ba and Rb),high field strength elements(HFSEs;Y,Zr and Nb),rare earth elements(REEs)and significantly depleted in K,Sr,P,Ti,and Eu,typically of post-collision A-type ***,the Amreit alkaline igneous rocks are classified as within plate granites and display A2 subtype *** fractionation of K-feldspars played a distinctive role during the magmatic evolution of these alkaline *** geochemical characteristics indicate that the studied alkaline igneous rocks which were originated by fractional crystallization of alkaline magmas were responsible for the enrichment of the REE and rare metals in the residual *** high radioactivity is essentially related to accessory minerals,such as zircon,allanite,and *** alkaline granite is the most U-and Thrich rock,where radioactivity level reaches up to 14.7 ppm(181.55 Bq/kg)e U,40.6 ppm(164.84 Bq/kg)e

关键词： Amreit area Alkaline rocks Radioactivity geochemistry Post-collision A-type granite Egypt