Studies in Lithium Oxide Systems: IX, Li2o-Al2O3-TiO2

Compatible phases in the system Li₂O-Al₂O₃-TiO₂ at various temperature levels were determined mainly by solid-state reactions for the portion of the ternary system bounded by Li₂O Al₂O₂, Li₂O.TiO₂, Al₂O, and TiO₂. The existence of a ternary compound, Li₂O.Al₂O₃.4TiO₂, and nine joins was established. The ternary compound has a lower limit of stability at 1090°± 15°C. and dissociates and recombines rapidly at 1380°± 15°C.     

Variable step-size affine projection algorithm based on global speech absence probability for adaptive feedbackcancellation简

A novel approach is proposed for improving adaptive feedback cancellation using a variable step-size affine projection algorithm（VSS-APA） based on global speech absence probability（GSAP）.The variable step-size of the proposed VSS-APA is adjusted according to the GSAP of the current frame.The weight vector of the adaptive filter is updated by the probability of the speech absence.The performance measure of acoustic feedback cancellation is evaluated using normalized misalignment.Experimental results demonstrate that the proposed approach has better performance than the normalized least mean square（NLMS） and the constant step-size affine projection algorithms.     

A hardware-based algorithm for virtual machine provisioning in a private cloud

Cloud computing is becoming a key factor in the market day by day. Therefore, many companies are investing or going to invest in this sector for development of large data centers. These data centers not only consume more energy but also produce greenhouse gases. Because of large amount of power consumption, data center providers go for different types of power generator to increase the profit margin which indirectly affects the environment. Several studies are carried out to reduce the power consumption of a data center. One of the techniques to reduce power consumption is virtualization. After several studies, it is stated that hardware plays a very important role. As the load increases, the power consumption of the CPU is also increased. Therefore, by extending the study of virtualization to reduce the power consumption, a hardware-based algorithm for virtual machine provisioning in a private cloud can significantly improve the performance by considering hardware as one of the important factors.     

Preparation of highly conductive reduced graphite oxide/poly(styrene-co-butyl acrylate) composites via miniemulsion polymerization

Polymer/reduced graphite oxide (rGO) composite nanoparticles with a high electrical conductivity were synthesized using the miniemulsion polymerization technique. The rGO was modified with a reactive surfactant, 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS), to facilitate monomer intercalation into the rGO nanogalleries. The AMPS-modified rGO was emulsified in the presence of styrene (St) and butyl acrylate (BA) monomers, and the stable miniemulsion was polymerized to form poly(St-co-BA)/rGO composite latex nanoparticles. The transition in the composite nanoparticles from an electrical insulator to an electrical conductor occurred at an rGO content of 10 wt% (relative to the monolayer content), yielding an electrical conductivity of 0.49 S/cm. The electrical conductivity of the composite nanoparticles reached 2.22 S/cm at 20 wt% rGO, yielding a much better conductivity than other polymer composites prepared using a GO filler. Importantly, the miniemulsion polymerization method for fabricating poly(St-co-BA)/rGO composite nanoparticles is easy, green, low-cost, and scalable, providing a universal route to the rational design and engineering of highly conductive polymer composites.     

亚临界和超临界状态下甲苯-多环芳香烃体系的气液相平衡

The phase behaviors of toluene/polycyclic aromatic hydrocarbon mixture systems were investigated with a continuous-flow type apparatus at 573.2,598.2.623.2 and 648.2K,while the pressure changed from 1 tp 5 MPa,The pseudo-binary phase behaviors were predicted with the Peng-Robinson equation of state with interaction parameters between toluene and pseudo-components considered.The phase diagrams of the system have been classified following the category of phase boundary diagram models.The extraction selectivity and efficiency of toluene as a solvent was discussed by comparing with that of hexane .The prediction model for selectivity was also suggested.     

A Direct Test for Cointegration Between a Pair of Time Series

In this paper we introduce a new test of the null hypothesis of no cointegration between a pair of time series. For a very simple generating model, our test compares favourably with the Engle–Granger/Dickey–Fuller test and the Johansen trace test. Indeed, shortcomings of the former motivated the development of our test. The applicability of our test is extended to series generated by low-order vector autoregressions. Again, we find evidence that this general version of our test is more powerful than the Johansen test. The paper concludes with an empirical example in which the new test finds strong evidence of cointegration, but the Johansen test does not.     

污泥厌氧消化过程中沼气原位提纯扩产技术的研究进展

目前,厌氧消化处是污泥减量化、无害化、资源化处理最有效的手段之一,沼气作为厌氧消化资源化产物,产量和纯度的原位提升技术有着重要的作用。文章从厌氧消化产沼气量影响因素和沼气原位富集技术的角度阐述沼气产量和纯度的提高的研究方法,从而对中国市政污泥处理和沼气能源化利用领域提供有价值的参考。     

EFFECTS OF SECONDARY AIR INJECTION ON GAS-SOLID FLOW BEHAVIOR IN CIRCULATING FLUIDIZED BEDS

Effects of secondary air injection on the hydrodynamics such as solid holdup and gas-solid flow behavior were investigated in a circulating fluidized bed. The gas velocity in the riser, the ratio of secondary air velocity to that of primary air, and the solid circulating rate were chosen as operating variables. Fluid cracking catalyst(FCC) with a density of 1840 kg/m³ and a mean diameter of 74 um was employed as the solid phase. The secondary air was fed to the riser radially or tangentially at the wall of the column. Pressure drop fluctuations in the riser were measured and analyzed by adopting the stochastic method to characterize the effects of secondary air injection on the gas-solid flow behavior in the bed.

It has been found that the injection of secondary air into the riser can increase the solid holdup in the riser considerably, and that the tangential injection of secondary air is more effective for the increasing the solid holdup than the radial injection. However, the gas-solid flow behavior has been found to become less persistent with the injection of secondary air; the resultant flow behavior is more complex when the air is injected tangentially than radially. The solid holdups in the primary as well as secondary zones of the riser have been well correlated in terms of not only operating variables but also fractal dimension of the pressure fluctuations.     

MODELING OF COPPER ION REMOVAL FROM AQUEOUS SOLUTIONS USING MODIFIED SILICA BEADS

Silica beads, containing 2-hydroxy-5-nonylacetophenoneoximc (LIX84) were prepared in order to examine the removal of copper ions from aqueous waste solutions. The process for copper ion removal using the modified silica beads was mathematically modeled using both a non-equilibrium model and an equilibrium model. The external mass transfer coefficient and effective diffusivity inside the bead pore were estimated by matching the experimental data and predicted values from the model, and the results were compared. The results of the two models were similar and in good agreement because of the relatively faster reaction rate than mass transfer rate. Sensitivity analyses showed that the external mass transfer has more influence on the copper ion removal system because of hydrophobic effects.     

EFFECTIVE DIFFUSIVITY ASSOCIATED WITH AXIAL TRANSPORT IN INSULATED OPEN-ENDED GORTER-MELLINK DUCTS

Steady, single-phase transport characterized by high eddy diffusivity in axial direction is a special case of vessel transport phenomena which has not been studied systematically so far. In the present paper, experiments are reported for a Gorter-Mellink duct, at zero net mass flow, covering turbulent eddy transport in cold He⁴ pressurized beyond its thermodynamic critical pressure above 4 K. Axial transport in vertical direction is induced by gravitational buoyancy. A new phenomenological equation is proposed on the basis of quantum fluid convection postulated originally for He II below the lambda point (Goner and Mellink, 1949). Our data agree reasonably with the equation.