Experimental Study on Ratio and Performance of Coal Gangue/Bottom Ash Geopolymer Double-Liquid Grouting Material

Mine grouting reinforcement and water plugging projects often require large amounts of grouting materials.To reduce the carbon emission of grouting material production,improve the utilization of solid waste from mining enterprises,and meet the needs of mine reinforcement and seepage control,a double-liquid grouting material containing a high admixture of coal gangue powder/bottom ash geopolymer was studied.The setting time,fluidity,bleeding rate,and mechanical properties of grouting materials were studied through laboratory tests,and SEM analyzed the microstructure of the materials.The results show that the total mixture of calcined gangue does not exceed 60%.And the proportion of bottom ash replacing cement should be within 30%.At the same time,the volume mixture of sodium silicate is 20%.And the water-solid ratio does not exceed 0.6.The stability of the slurry prepared under this ratio is good.The microstructure of the stone body is dense,and its strength can meet the requirements of rock reinforcement and seepage control.Its economic and environmental benefits are more significant than the traditional cement-silicate double-liquid grouting material.

Interface crack problems for mode Ⅱ of double dissimilar orthotropic composite materials

The fracture problems near the similar orthotropic composite materials are interface crack tip for mode Ⅱ of double disstudied. The mechanical models of interface crack for mode Ⅱ are given. By translating the governing equations into the generalized hi-harmonic equations, the stress functions containing two stress singularity exponents are derived with the help of a complex function method. Based on the boundary conditions, a system of non-homogeneous linear equations is found. Two real stress singularity exponents are determined be solving this system under appropriate conditions about bimaterial engineering parameters. According to the uniqueness theorem of limit, both the formulae of stress intensity factors and theoretical solutions of stress field near the interface crack tip are derived. When the two orthotropic materials are the same, the stress singularity exponents, stress intensity factors and stresses for mode II crack of the orthotropic single material are obtained.

Crack-tip field on mode Ⅱ interface crack of double dissimilar orthotropic composite materials

Two systems of non-homogeneous linear equations with 8 unknowns are obtained.This is done by introducing two stress functions containing 16 undetermined coefficients and two real stress singularity exponents with the help of boundary conditions.By solving the above systems of non-homogeneous linear equations,the two real stress singularity exponents can be determined when the double material parameters meet certain conditions.The expression of the stress function and all coefficients are obtained based on the uniqueness theorem of limit.By substituting these parameters into the corresponding mechanics equations,theoretical solutions to the stress intensity factor,the stress field and the displacement field near the crack tip of each material can be obtained when both discriminants of the characteristic equations are less than zero.Stress and displacement near the crack tip show mixed crack characteristics without stress oscillation and crack surface overlapping.As an example,when the two orthotropic materials are the same,the stress singularity exponent,the stress intensity factor,and expressions for the stress and the displacement fields of the orthotropic single materials can be derived.

Nonlinear thermo-mechanical stability of eccentrically stiffened functionally graded material sandwich doubly curved shallow shells with general sigmoid law and power law according to third-order shear deformation theory

In this paper, the nonlinear analysis of stability of functionally graded ma- terial （FGM） sandwich doubly curved shallow shells is studied under thermo-mechanical loads with material properties obeying the general sigmoid law and power law of four ma- terial models. Shells are reinforced by the FGM stiffeners and rest on elastic foundations. Theoretical formulations are derived by the third-order shear deformation theory （TSDT） with the von Karman-type nonlinearity taking into account the initial geometrical im- perfection and smeared stiffener technique. The explicit expressions for determining the critical buckling load and the post-buckling mechanical and thermal load-deflection curves are obtained by the Galerkin method. Two iterative algorithms are presented. The effects of the stiffeners, the thermal element, the distribution law of material, the initial imper- fection, the foundation, and the geometrical parameters on buckling and post-buckling of shells are investigated.

The impact of gate misalignment on the analog performance of a dual-material double gate junctionless transistor

The analog performance of gate misaligned dual material double gate junctionless transistor is demonstrated for the first time. The cases considered are where misalignment occurs towards source side and towards drain side. The analog performance parameters analyzed are： transconductance, output conductance, intrinsic gain and cut-off frequency. These figures of merits （FOMs） are compared with a dual material double gate inversion mode transistor under same gate misalignment condition. The impacts of different length of control gate （L 1） for a given gate length （L） are also studied and the optimum lengths La under misalignment condition to have better analog FOMs and high tolerance to misalignment are presented.

A compact model for single material double work function gate MOSFET

An analytical surface potential model for the single material double work function gate （SMDWG） MOSFET is developed based on the exact resultant solution of the two-dimensional Poisson equation. The model includes the effects of drain biases, gate oxide thickness, different combinations of S-gate and D-gate length and values of substrate doping concentration. More attention has been paid to seeking to explain the attributes of the SMDWG MOSFET, such as suppressing drain-induced barrier lowering （DIBL）, accelerating carrier drift velocity and device speed. The model is verified by comparison to the simulated results using the device simulator MEDICI. The accuracy of the results obtained using our analytical model is verified using numerical simulations. The model not only offers the physical insight into device physics but also provides the basic designing guideline for the device.

Poroelastic solid flow with double point material point method

This paper presents the numerical modelling of one and two-dimensional poroelastic solid flows,using the material point method with double point formulation.The double point formulation offers the convenience of allowing for transitions in the flow conditions of the liquid,between free surface flow and groundwater flow.The numerical model is validated by comparing the solid flow velocity with the analytical solution.The influence of the Young＇s modulus on the solid flow velocity is discussed for both one and two-dimensional analysis cases.The effect of the shape of the two-dimensional solid is investigated.It is shown that the solid stiffness has an effect on the poroelastic flow velocity,due to swelling and bending for the one and two-dimensional cases,respectively.The shape is found to be an important factor on the flow velocity of the poroelastic solid.

Synthesis of layered cathode materials Li[Co_x Ni_y Mn_(1-x-y)]O_2 from layered double hydroxide precursors

Cathode materials Li[CoxNiyMn1-x-y]O2 for lithium secondary batteries have been prepared by a new route using layered double hydroxides （LDHs） as a precursor. The resulting layered phase with the α- NaFe02 structure crystallizes in the rhombohedral system, with space group R-3m having an interlayer spacing close to 0.47 nm. X-ray photoelectron spectroscopy （XPS） was used to measure the oxidation states of Co, Ni and Mn. The effects of varying the Co[Ni[Mn ratio on both the structure and electrochemical properties of Li[CoxNiyMn1-x-y]O2 have been investigated by X-ray diffraction and electrochemical tests. The products demonstrated a rather stable cycling behavior, with a reversible capacity of 118 mAh/g for the layered material with Co/Ni/Mn = 1/1/1.

Memory response in a nonlocal micropolar double porous thermoelastic medium with variable conductivity under Moore-Gibson-Thompson thermoelasticity theory

The present study enlightens the two-dimensional analysis of the thermo-mechanical response for a mi-cropolar double porous thermoelastic material with voids(MDPTMWV)by virtue of Eringen’s theory of nonlocal elasticity.Moore-Gibson-Thompson(MGT)heat equation is introduced to the considered model in the context of memory-dependent derivative and variable conductivity.By employing the normal mode technique,the non-dimensional coupled governing equations of motion are solved to determine the an-alytical expressions of the displacements,temperature,void volume fractions,microrotation vector,force stress tensors,and equilibrated stress vectors.Several two-dimensional graphs are presented to demon-strate the influence of various parameters,such as kernel functions,thermal conductivity,and nonlocality.Furthermore,different generalized thermoelasticity theories with variable conductivity are compared to visualize the variations in the distributions associated with the prior mentioned variables.Some particu-lar cases are also discussed in the presence and absence of different parameters.