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1.
Experimental studies on phase equilibria in the multicomponent system PbO-ZnO-CaO-SiO2-FeO-Fe2O3 in air have been conducted to characterize the phase relations of a complex slag system used in commercial lead oxidation
smelting. The liquidus in the pseudo-ternary section ZnO-“Fe2O3”-(PbO + CaO + SiO2) with the CaO/SiO2 weight ratio of 0.35 and the PbO/(CaO + SiO2) weight ratio of 5.0 has been constructed using results of over 100 high-temperature equilibration and quenching experiments
followed by electron probe X-ray microanalysis. The liquidus in this pseudoternary section contains primary phase fields of
spinel (zinc ferrite) Zn
x
Fe3−x
O4+y
, zincite Zn
u
Fe1−u
O, melilite Pb
v
Ca2−v
Zn
w
Fe1−w
Si2O7, hematite Fe2O3, magneto-plumbite PbFe10O16, and dicalcium silicate Ca2−t
Pb
t
SiO4. The laboratory results are compared with the slags obtained from an industrial reactor. 相似文献
2.
Evgueni T. Filipov Junho Chun Glaucio H. Paulino Junho Song 《Structural and Multidisciplinary Optimization》2016,53(4):673-694
We use versatile polygonal elements along with a multiresolution scheme for topology optimization to achieve computationally efficient and high resolution designs for structural dynamics problems. The multiresolution scheme uses a coarse finite element mesh to perform the analysis, a fine design variable mesh for the optimization and a fine density variable mesh to represent the material distribution. The finite element discretization employs a conforming finite element mesh. The design variable and density discretizations employ either matching or non-matching grids to provide a finer discretization for the density and design variables. Examples are shown for the optimization of structural eigenfrequencies and forced vibration problems. 相似文献
3.
Level‐set topology optimization with many linear buckling constraints using an efficient and robust eigensolver 下载免费PDF全文
Peter D. Dunning Evgueni Ovtchinnikov Jennifer Scott H. Alicia Kim 《International journal for numerical methods in engineering》2016,107(12):1029-1053
Linear buckling constraints are important in structural topology optimization for obtaining designs that can support the required loads without failure. During the optimization process, the critical buckling eigenmode can change; this poses a challenge to gradient‐based optimization and can require the computation of a large number of linear buckling eigenmodes. This is potentially both computationally difficult to achieve and prohibitively expensive. In this paper, we motivate the need for a large number of linear buckling modes and show how several features of the block Jacobi conjugate gradient (BJCG) eigenvalue method, including optimal shift estimates, the reuse of eigenvectors, adaptive eigenvector tolerances and multiple shifts, can be used to efficiently and robustly compute a large number of buckling eigenmodes. This paper also introduces linear buckling constraints for level‐set topology optimization. In our approach, the velocity function is defined as a weighted sum of the shape sensitivities for the objective and constraint functions. The weights are found by solving an optimization sub‐problem to reduce the mass while maintaining feasibility of the buckling constraints. The effectiveness of this approach in combination with the BJCG method is demonstrated using a 3D optimization problem. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
4.
We investigated intrinsic noise in plasmonic sensors caused by adsorption and desorption of gaseous analytes on the sensor
surface. We analyzed a general situation when there is a larger number of different analyte species. We applied our model
to calculate various analyte mixtures, including some environmental pollutants, toxic and dangerous substances. The spectral
density of mean square refractive index fluctuations follows a dependence similar to that of generation-recombination noise
in photodetectors, flat at lower frequencies and sharply decreasing at higher. Some of the calculated noise levels are well
within the detection range of conventional surface plasmon resonance sensors. An AD noise peak is observed in temperature
dependence of mean square refractive index fluctuations, thus sensor operating temperature may be optimized to obtain larger
signal to noise ratio. A significant property of AD noise is its rise with the decreasing plasmon sensor area, which means
that it will be even more pronounced in modern nanoplasmonic devices. Our consideration is valid both for conventional surface
plasmon resonance devices and for general nanoplasmonic devices. 相似文献
5.
Ata Fallah-Mehrjardi Peter C. Hayes Evgueni Jak 《Metallurgical and Materials Transactions B》2013,44(6):1337-1351
Freeze-lining technologies have been employed to protect the cooling walls of reactors from chemically aggressive molten reactants. To date, the designs of freeze linings for pyrometallurgical reactors have been based on the basic assumption that the interface between the deposit and the bath remains at the liquidus temperature of the bulk liquid. There is, however, increasing evidence that interface temperature between stagnant deposit and bath is less than the liquidus of the bulk liquid. A previous study also demonstrated that the effects of bath chemistry need to be taken into account in freeze-lining designs. To investigate the fundamental processes involved in the formation and stability of the deposit, experimental laboratory studies have been undertaken in the Cu-Fe-Si-Al-O slag system in equilibrium with metallic copper using an air-cooled probe technique. In the current study, the effects of bath agitation on the microstructure, morphologies of the phases, and formation of various layers across the freeze-lining deposit were studied at steady-state conditions. It appears that the changes in the fluid flow pattern through changes in shear intensities result in corresponding changes in the deposit microstructure, formation of the sealing primary phase layer, thus influencing the interface temperature between freeze-lining deposit and the liquid bath. 相似文献
6.
Phase equilibria of the binary PbO-ZnO and ternary PbO-ZnO-SiO2 systems have been experimentally investigated at 1033–1898?K (760–1625?°C) for oxide liquid in equilibrium with air and solid oxide phases: tridymite or cristobalite (SiO2), willemite (Zn2SiO4), zincite (ZnO), larsenite (PbZnSiO4) and lead-zinc melilite (Pb2ZnSi2O7) covering the ranges of concentrations not studied before. High-temperature equilibration on primary phase or inert metal (platinum) substrates, followed by quenching and direct measurement of the Pb, Zn and Si concentrations in the phases with the electron probe X-ray microanalysis (EPMA) has been used. Liquidus phase equilibrium data is essential for the development of the thermodynamic model. 相似文献
7.
8.
Taufiq Hidayat Peter C. Hayes Evgueni Jak 《Metallurgical and Materials Transactions B》2012,43(1):14-26
Ferrous calcium silicate slags, whose principal components are “FeO
x
”-CaO-SiO2, are widely used in copper smelting and converting operations. In the current study, high-temperature equilibration and rapid
quenching techniques were used to study the phase equilibria of the ferrous calcium silicate slags. The compositions of phases
in the slags were measured accurately using electron probe X-ray microanalysis (EPMA). The phase equilibria of the system
have been characterized at oxygen partial pressures between 10−5 atm and 10−7 atm at selected temperatures between 1473 K and 1623 K (1200 °C and 1350 °C). The effects of oxygen partial pressure and temperature
on the compositions of phases in the slags are presented. 相似文献
9.
M. Bogovac M. Jakšić D. Wegrzynek A. Markowicz 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2009,267(12-13):2073-2076
Capabilities of spectroscopic ion beam analysis (IBA) techniques that are available in ion microprobe facilities can be greatly improved by the use of digital pulse processing. We report here development of a digital multi parameter data acquisition system suitable for IBA imaging applications. Input signals from charge sensitive preamplifier are conditioned by using a simple circuit and digitized with fast ADCs. The digitally converted signals are processed in real time using FPGA. Implementation of several components of the system is presented. 相似文献
10.
E. Vittone N. Skukan Ž. Pastuović P. Olivero M. Jakšić 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2009,267(12-13):2197-2202
The Ion Beam Induced Charge (IBIC) technique was used to map the charge collection efficiency (CCE) of a 4H–SiC photodetector with coplanar interdigitated Schottky barrier electrodes and a common ohmic contact on the back side.IBIC maps were obtained using focused proton beams with energies of 0.9 and 1.5 MeV, at different bias voltages and different sensitive electrode configurations (charge collection at the top Schottky or at the back Ohmic contact).These different experimental conditions have been modeled using a two-dimensional finite element code to solve the adjoint carrier continuity equations and the results obtained have been compared with experimental results. The excellent agreement between the simulated and experimental CCE maps allows an exhaustive interpretation of the charge collection mechanisms occurring in pixellated or strip detectors. 相似文献