Separability property and ηpl factor in ASTM A387-Gr22 steel plate

In this work the possibility of obtaining the function G(b/W) from the variable separability property to calculate η_pl factor following the methodology proposed by Sharobeam and Landes using a deformation function H with total displacement was studied. The material employed was an ASTM A387-Gr22 steel plate and standard ASTM SE(B) and C(T) geometries were used for the test pieces with different side grooving ratios.For SE(B) specimens, the differences observed between η_pl factor values determined with total displacement, plastic displacement and that recommended in ASTM 1820-96 were not significant. For C(T) specimens, the differences observed were lower than 2% for all side grooving ratios studied. The η_pl factor values resulting from the use of Sharobeam and Landes methodology using total and plastic displacement did not seem to follow the dependence with crack length suggested by ASTM E1820-96. It was not possible within the scope of this work to find a side groove influence on the η_pl factor value for this geometry.     

Experimental J estimation equations for single-edge-cracked bars in four-point bend: homogeneous and bi-material specimens

The present paper provides the plastic η factor solutions for J testing of single-edge-cracked specimens in four-point bend (SE(PB)), based on limit (slip line field) and detailed finite element limit analyses. Both homogeneous specimens and bi-material specimens with interface cracks are considered. Moreover, two different η factor solutions are developed, one for J (or C^* in creep crack growth testing) estimation based on the load-load line displacement (LLD) records, η_p^VLL, and the other J estimation based on the load-crack mouth opening displacement (CMOD) records, η_p^CMOD.It is found that the use of load-LLD records can be recommended only for testing deeply cracked SE(PB) specimens. Moreover, depending on how the LLD is measured, a different value of η_p^VLL should be used. On the other hand, the use of load-CMOD records is recommended for all possible crack lengths. Moreover, the proposed η_p^CMOD solution can be used not only for a homogeneous specimen but also for any bi-material specimen with an interface crack.     

Evidence for η6 Coordination to a Fullerene

Abstract

Evidence for the first η⁶ derivative of a fullerene, [MoC₆₀F₁₈(CO)₃] has been obtained from reaction between [Mo(CH₃CN)₃(CO)₃] and C₆₀F₁₈.     

(g,η)-增生算子及变分包含问题(英文)

在没有假定多值映射是连续映射的条件下,得到了(g,η)-增生算子、广义豫解算子和(g,η)-增生算子产生的广义Yosida近似的一些性质,并应用这些性质证明了一类变分包含问题的解的存在性.     

Least-squares problem for the quaternion matrix equation AXB+CYD=E over different constrained matrices

For any A=A ₁+A ₂ j∈Q ^n×n and η∈<texlscub>i, j, k</texlscub>, denote A ^{η H} =?η A ^H η. If A ^{η H} =A, A is called an $\eta$-Hermitian matrix. If A ^{η H} =?A, A is called an η-anti-Hermitian matrix. Denote η-Hermitian matrices and η-anti-Hermitian matrices by η HQ ^n×n and η AQ ^n×n , respectively.

By using the complex representation of quaternion matrices, the Moore–Penrose generalized inverse and the Kronecker product of matrices, we derive the expressions of the least-squares solution with the least norm for the quaternion matrix equation AXB+CYD=E over X∈η HQ ^n×n and Y∈η AQ ^n×n .     

二维超导η-Mo3C2薄膜的可控制备

二维超导体具有丰富的物理特性和非常广泛的潜在应用.最近,有报道制备出具有二维超导特性的α-Mo2C和面心立方Mo2C,这些材料为碳基超导的研究带来了新的方向.碳化钼具有多种晶体结构,除了目前已经被制备的种类外,二维碳化钼尚没有新的晶体结构被制备出来,这或许是因为在制备过程中缺乏额外的能量供给.在本工作中,我们进一步发展...     

Estimation procedure of J-resistance curves for SE(T) fracture specimens using unloading compliance

This work provides an estimation procedure to determine J-resistance curves for pin-loaded and clamped SE(T) fracture specimens using the unloading compliance technique and the η-method. A summary of the methodology upon which J and crack extension are derived sets the necessary framework to determine crack resistance data from the measured load vs. displacement curves. The extensive plane-strain analyses enable numerical estimates of the nondimensional compliance, μ, and parameters η and γ for a wide range of specimen geometries and material properties characteristic of structural and pipeline steels. Laboratory testing of an API 5L X60 steel at room temperature using pin-loaded SE(T) specimens with side-grooves provide the load-displacement data needed to validate the estimation procedure for measuring the crack growth resistance curve for the material. The results presented here produce a representative set of solutions which lend further support to develop standard test procedures for constraint-designed SE(T) specimens applicable in measurements of crack growth resistance for pipelines.     

Experimental investigation of prechamber autoignition in a natural gas engine for cogeneration

A novel ignition concept based on autoignition in an unscavanged prechamber is currently being developed at the Laboratory for Industrial Energy Systems (LENI). On a single cylinder test engine a series of experimental runs (CR = 8.5-14, λ = 1 − 1.6, RPM = 1150/1500 min⁻¹) have been realized with natural gas as fuel, comparing the new ignition concept to standard spark ignition. The comparison is based on fuel efficiency and exhaust emissions (CO, THC, NO_x). The feasibility of operating the engine in autoignition mode has been demonstrated, and the potential of prechamber autoignition, in particular in the lean combustion regime, is indicated by the trends in fuel efficiency and emission concentration. The resistive heating of the prechamber walls has been shown to be an effective mean to trigger ignition. The prechamber could clearly be identified as primary ignition location. A reduction of the cycle-by-cycle variations - due to mixture fluctuations - is necessary to exploit the full potential of this engine concept.     

Second-order duality for non-differentiable minimax fractional programming

In this paper, a second-order duality for a non-differentiable minimax fractional programming is formulated by generalizing the one developed by Husian et al. [Second order duality for minimax fractional programming, Optim. Lett. 3 (2009), pp. 277–286], for the minimax fractional programming. The weak, strong and strict converse duality theorems are proved for these programs under generalized η-bonvexity assumptions.     

Optimisation of the MgO/Al2O3 ratio of high-alumina BF slag based on MOPSO algorithm

To reduce the content of MgO in the slag, which helps in lowering production costs, the chemical components of a SiO₂–CaO–MgO–Al₂O₃–TiO₂ blast furnace (BF) slag system with high Al₂O₃ content were optimised using the multi-objective particle swarm optimisation (MOPSO) algorithm. First, models for predicting the metallurgical properties of BF slag were established and verified, based on mixture experimental designs and the ion and molecule coexistence theory. Second, the problem was solved by MOPSO using the MATLAB software package. Optimisation results show that the appropriate content of MgO in the slag should be 4–7%, and the MgO/Al₂O₃ ratio should be 0.2–0.6. Finally, optimised solutions were used in the 3200?m³ BF of a steel company in China. MgO in the slag was reduced to less than 5%, the MgO/Al₂O₃ ratio was controlled at 0.3–0.4, and the fuel ratio remained at 515?kg?t^?1.