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In this paper, nonlinear dynamic responses of bi-stable laminate being simply supported on four corner points, which is subjected to various impact loads, are analyzed from theoretical viewpoints. Consider a four layers asymmetric cross-ply bi-stable laminate composited by the carbon fiber reinforced resin matrix. A novel configuration function that satisfies the boundary condition is proposed to predict the equilibrium configuration. Then, employing the first order shear deformation theory, the von Kàrmàn strains and Hamilton principle, nonlinear dynamic equations of motion expressed by two curvatures are derived. To obtain the two stable configurations of the laminate, the inertia terms are ignored. With the aids of static equilibrium equation, the side length and curvature of the system are solved by using NLPSolve functions in the Maple software. The stable configurations are verified by comparing present results with those reported in available literatures. Consider the incremental load loading, the decreasing loading, the sinusoidal loading, the step loading, the triangular loading and periodic loading, the nonlinear dynamic response of the bi-stable laminate are discussed. The dynamic snap-through behavior, the intra-well oscillations and inter-wall oscillations are studied by numerical simulation in detail. [ABSTRACT FROM AUTHOR]

This paper researches the free vibrations and corresponding material parameters of a functional gradient graphene platelets-reinforced composite (FG-GPLRC) cantilever torsional plates with both pore and graphene variations in the transverse direction. Utilizing the feature of closed-cell cellular solids, the mixture rule, and the modified Halpin–Tsai model, the material parameters of the composite are determined for different volume fractions of component materials. Then, using the classical plate theory (CLPT), the Rayleigh–Ritz technique and polynomials, the dynamic equation that can be used to obtain the free vibration mode shapes and frequencies of the rotating cantilever torsional plate is given. Comparison studies with the previous calculation results from available literature and the finite element (FE) models of cantilever plates are conducted, and the correctness of the present theoretical formulation and numerical calculation is verified. Finally, the effects of graphene platelet (GPL) distribution, porosity distribution (PD), GPL content, rotational speed, and average geometric size of GPL on free vibrations of the system are studied in depth. [ABSTRACT FROM AUTHOR]

The phenomenon of poor cycle stability can be effectively solved by using metal–organic frameworks (MOFs) as precursor to obtain oxides. In this work, a layered NiO@NiCo2O4 nanocomposite electrodes were designed from bimetallic (Ni/Co) based bimetallic metal–organic framework (Ni/Co-MOF) by simple hydrothermal method followed by subsequent controlled calcination under air atmosphere at various temperatures for the transition process. XRD and FE-SEM studies were substantiating the formation of MOF derived NiO@NiCo2O4 nanocomposite with layered structure. Interestingly, electrochemical studies shows that MOF derived NiO@NiCo2O4 nanocomposite achieved at the calcination temperature at 300 °C and 400 °C demonstrates high specific capacitance of 2461 F/g and 2180 F/g at the current density of 1 A/g, which keeps the precursor Ni/Co-MOF with high specific capacitance peculiarity of 2250 F/g at 2 A/g. In terms of cycle retention rate, the NiO@NiCo2O4 nanocomposite obtained at 400 °C still has a high retention rate of 78% under the current density of 15 A/g for 4500 cycles. It significantly improved the precursor Ni/Co-MOF low cycle retention rate of only 56% after 1000 cycles. The results show that the metal oxide nanocomposites calcined with MOFs as sacrificial template not only retain the high specific capacitance characteristics of MOFs, but also improve its low cycle stability, which has great potential in electrochemical supercapacitor electrode materials and provides a certain useful reference for the direction of global energy demand. [ABSTRACT FROM AUTHOR]

This report is based on a ten-week program on "Gluons and the quark sea athigh-energies", which took place at the Institute for Nuclear Theory in Seattlein Fall 2010. The principal aim of the program was to develop and sharpen thescience case for an Electron-Ion Collider (EIC), a facility that will be ableto collide electrons and positrons with polarized protons and with light toheavy nuclei at high energies, offering unprecedented possibilities forin-depth studies of quantum chromodynamics. This report is organized aroundfour major themes: i) the spin and flavor structure of the proton, ii)three-dimensional structure of nucleons and nuclei in momentum andconfiguration space, iii) QCD matter in nuclei, and iv) Electroweak physics andthe search for physics beyond the Standard Model. Beginning with an executivesummary, the report contains tables of key measurements, chapter overviews foreach of the major scientific themes, and detailed individual contributions onvarious aspects of the scientific opportunities presented by an EIC.

Various thermal-hydrologic models have been developed to simulate thermal-hydrologic conditions in emplacement drifts and surrounding host rock for the proposed high-level nuclear waste repository at Yucca Mountain, Nevada. The modeling involves two-phase (liquid and gas) and two-component (water and air) transport in a fractured-rock system, which is conceptualized as a dual-permeability medium. Simulated hydrologic processes depend upon calibrated system parameters, such as the van Genuchten α and m, which quantify the capillary properties of the fractures and rock matrix. Typically, these parameters are not calibrated for strongly heat-driven conditions, i.e., conditions for which boiling and rock dryout occur. The objective of this study is to modify the relationship between capillary pressure and saturation, P c(S), for strongly heated conditions that drive saturation below the residual saturation (S → 0). We offer various extensions to the van Genuchten capillary-pressure function and compare results from a thermal-hydrologic model with data collected during the Drift-Scale Test, an in situ thermal test at Yucca Mountain, to investigate the suitability of these various P c extension methods. The study suggests that the use of extension methods and the imposition of a capillary-pressure cap (or maximum) improve the agreement between Drift-Scale Test data and model results for strongly heat-driven conditions. However, for thermal-hydrologic models of the Yucca Mountain nuclear waste repository, temperature and relative humidity are insensitive to the choice of extension method for the capillary-pressure function. Therefore, the choice of extension method applied to models of drift-scale thermal-hydrologic behavior at Yucca Mountain can be made on the basis of numerical performance.

AbstractThe cross-well dynamic of the bi-stable laminates triggered by ambient vibration is a typical nonlinear dynamic, the larger deformation makes the bi-stable laminates attract much attention in vibration energy harvesting. To obtain the performance of cross-well dynamics and vibration energy harvesting of the bi-stable laminate theoretically, a 4-layer harmonic base-excited antisymmetric cross-ply bi-stable laminates with d31 type Marco fiber composite (MFC) for vibration energy harvesting is proposed. The bi-stable laminate is fixed at a chosen point where a base excitation is applied as displacement excitation. The first order shear deformation laminated plate theory (FSDT), geometric nonlinear, and the energy principle are employed to obtain the governing equation of the system in terms of the polynomial coefficients of configuration functions. Two stable configurations are calculated by the principle of minimum potential energy, which is used as the initial state for the energy harvesting analysis. The stable configurations are predicted, and evaluated by comparing them with ABAQUS. The cross-well nonlinear dynamic behaviors and the performance of energy harvesting are analyzed. The effects of excitation level, excitation frequency, and the position of the fixed point on the cross-well dynamics and energy harvest characteristics of the antisymmetric bi-stable laminates are investigated in-depth, and some new aspects are revealed. It demonstrates that the base displacement harmonic excitation can induce chaotic cross-well vibration in a high-frequency band when the fixed point is far away from the center point, the various cross-well vibration of the system is more likely to occur in the dominate-frequency resonant band. [ABSTRACT FROM AUTHOR]

Xerocomoideae is an ecologically and economically important Boletaceae subfamily (Boletales) comprising 10 genera. Although many studies have focused on Xerocomoideae in China, the diversity, taxonomy and molecular phylogeny still remained incompletely understood. In the present study, taxonomic and phylogenetic studies on Chinese species of Xerocomoideae were carried out by morphological examinations and molecular phylogenetic analyses. Eight genera in Xerocomoideae, viz. Aureoboletus, Boletellus, Heimioporus, Hemileccinum, Hourangia, Phylloporus, Pulchroboletus, and Xerocomus were confirmed to be distributed in China; 97 species of the subfamily were accepted as being distributed in China; one ambiguous taxon was tentatively named Bol. aff. putuoensis; two synonyms, viz. A. marroninus and P. dimorphus were defined. Among the Chinese accepted species, 13 were newly described, viz. A. albipes, A. conicus, A. ornatipes, Bol. erythrolepis, Bol. rubidus, Bol. sinochrysenteroides, Bol. subglobosus, Bol. zenghuoxingii, H. squamipes, P. hainanensis, Pul. erubescens, X. albotomentosus, and X. fuscatus, 36 known species were redescribed, and the other 48 species were reviewed. Keys to accepted species of Aureoboletus, Boletellus, Heimioporus, Hemileccinum, Hourangia, Phylloporus, and Xerocomus in China were also provided. [ABSTRACT FROM AUTHOR]

The severe cadmium (Cd) pollution of soil adversely affects food safety and human health. To prevent phytotoxicity and Cd accumulation in agricultural products, effective steps must be taken immediately. In the study, we added different concentrations (10, 50, and 250 mg/kg) of α-Fe2O3 nanoparticles (NPs) into Cd-contaminated soil, investigating the effects of α-Fe2O3 NPs on Cd toxicity. The various physiological indicators, such as antioxidant system, the distribution of Cd and the content of active ingredients in different parts of muskmelon were detected. The results revealed that α-Fe2O3 NPs greatly reduce Cd transport in plants and minimize Cd toxicity. Specifically, 250 mg/kg α-Fe2O3 NPs treatment reduced the root Cd content by 30.19% and 50 mg/kg α-Fe2O3 NPs treatment reduced the stem Cd content by 38.75%. For the content of active ingredients, 50 mg/kg α-Fe2O3 NPs treatment increased root polysaccharide content and leaf saponin content by 14.45 and 27.71%, respectively. Overall, α-Fe2O3 NPs can reduce Cd stress in muskmelon. The current work gave a unique notion for Cd remediation in soil using α-Fe2O3 NPs as amendments. [ABSTRACT FROM AUTHOR]

This paper presents the optimal designs of pinned supported funicular arches under equally spaced point loads for maximum in-plane buckling load. Under such loading conditions, the funicular arch shapes comprise straight arch members between the point loads, that is, following the shape of the bending moment diagram of an equivalent simply supported beam under the same loading condition. Two classes of funicular arch optimization problems are considered herein. The first class of funicular arches imposes a constraint on the cross-sectional area to be uniform throughout the entire arch length. The second class of funicular arches allows the cross-sectional area to be different from one straight arch member to another member. To facilitate the buckling analysis, the Hencky bar-chain model (HBM) is adopted. This discrete structural model simplifies the optimization process as the decision variables are the HBM rotational spring stiffnesses that define the cross-sectional areas and the horizontal force that controls the arch shape. Presented herein are new optimal funicular arch shapes under various numbers of equally spaced point loads. By increasing the number of point loads, the optimal solution approaches the solution of a parabolic arch under a uniformly distributed load. [ABSTRACT FROM AUTHOR]

The mixing of oil and gas forms the foundation of deep-sea oil and gas extraction and transportation. However, traditional conveying equipment has low efficiency and high failure rates. In this study, a spiral axial flow gas and liquid multiphase pump was used as the base model. The Eulerian multiphase flow model and RNG turbulence model were used for numerical simulations to analyze the internal flow field of the multiphase pump. A modification scheme was proposed to twist the airfoil shape and create a twisted vane. The twisted blade with the center of the hub-side flange chord length as the twisting center was twisted in the counterclockwise direction to help reduce the relative volume of gas in the flow channel. When the twisted vane with the hub-side airfoil type trailing edge point as the twisting center was twisted in the suction side direction, it helped to accelerate the movement of the gas-liquid mixture at the trailing edge of the back of the vane and further reduced the low velocity zone at the back of the vane. When the twist center is located at the hub side wing type trailing edge point of the twist vane, the twist degree is 0.214. This results in the maximum head and efficiency of the pump, improves gas phase aggregation phenomenon, and enhances the performance of the multiphase pump. [ABSTRACT FROM AUTHOR]