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Synthesis of low-cost porous ceramic microspheres from waste gangue for dye adsorption

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Journal of Advanced Ceramics 2018年第1期7卷 30-40页

作者： Shu YAN Yiming PAN Lu WANG Jingjing LIU Zaijuan ZHANG Wenlong HUO Jinlong YANG Yong HUANG State Key Laboratory of New Ceramics and Fine Processing School of Materials Science and Engineering Tsinghua University school of Materials science and engineering Dalian Jiaotong University

Low-cost porous ceramic microspheres from waste gangue were prepared by simple spray drying and subsequent calcination. Effects of calcination temperature on phase and microstructure evolution, specific surface area, pore structure, and dye adsorption mechanism of the microspheres were investigated systematically. Results showed that the microspheres were spherical, with some mesopores both on the surface and inside the spheres. The phase kept kaolinite after calcined at 800 and 900 ℃ and transformed into mullite at 1000 ℃. The microspheres calcined at 800 ℃ showed larger adsorption capacity and removal efficiency than those calcined at higher temperatures. Methylene blue(MB) and basic fuchsin(BF) removal efficiency reached 100% and 99.9% with the microsphere dosage of 20 g/L, respectively, which was comparable to that of other low-cost waste adsorbents used to remove dyes in the literature. Adsorption kinetics data followed the pseudosecond-order kinetic model, and the isotherm data fit the Langmuir isotherm model. The adsorption process was attributed to multiple adsorption mechanisms including physical adsorption, hydrogen bonding, and electrostatic interactions between dyes and gangue microspheres. The low-cost porous microspheres with excellent cyclic regeneration properties are promising absorbent for dyes in wastewater filtration and adsorption treatment.

关键词： adsorption microspheres calcination microstructure equilibrium

DISTRIBUTED MONITORING SYSTEM RELIABILITY ESTIMATION WITH CONSIDERATION OF STATISTICAL UNCERTAINTY

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Chinese Journal of Mechanical engineering 2005年第4期18卷 519-524页

作者： Yi Pengxing Yang Shuzi Du Runsheng Wu Bo Liu Shiyuan school of Mechanical science and engineering Huazhong University of Science and Technology Wuhan 430074 China

Taking into account the whole system structure and the component reliability estimation uncertainty, a system reliability estimation method based on probability and statistical theory for distributed monitoring systems is presented. The variance and confidence intervals of the system reliability estimation are obtained by expressing system reliability as a linear sum of products of higher order moments of component reliability estimates when the number of component or system survivals obeys binomial distribution. The eigenfunction of binomial distribution is used to determine the moments of component reliability estimates, and a symbolic matrix which can facilitate the search of explicit system reliability estimates is proposed. Furthermore, a case of application is used to illustrate the procedure, and with the help of this example, various issues such as the applicability of this estimation model, and measures to improve system reliability of monitoring systems are discussed.

关键词： Distributed monitoring system Statistical uncertainty Variance Confidence intervals System reliability estimation

Transformation between polar and rectangular coordinates of stiffness and dampness parameters in hydrodynamic journal bearings

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Friction 2021年第1期9卷 201-206页

作者： Zhuxin TIAN Yu HUANG school of Mechanical engineering Hubei University of Arts and ScienceXiangyang 441053China State Key Lab of Digital Manufacturing Equipment and Technology School of Mechanical Science and EngineeringHuazhong University of Science and TechnologyWuhan 430074China

The stiffness and dampness parameters of journal bearings are required in rectangular coordinates for analyzing the stability boundary and threshold speed of oil film *** solving the Reynolds equation,the oil film force is always obtained in polar coordinates;thus,the stiffness and dampness parameters can be easily obtained in polar ***,the transformation between the polar and rectangular coordinates of journal bearing stiffness and dampness parameters is discussed in this study.

关键词： coordinate transformation stiffness parameters dampness parameters hydrodynamic journal bearings

Development of Microbe Cementitious Material in China

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Journal of Shanghai Jiaotong university(science) 2012年第3期17卷 350-355页

作者：荣辉钱春香 school of Materials science and engineering Southeast University

Microbe cementitious material as a binder has been developed due to the ever increasing awareness of environmental *** new cementitious material relies on microbiologically induced precipitation of calcium carbonate to bind loose particles or repair surface defects and cracks of cement-based *** paper elaborates the research on loose sand particles cemented by microbe cement from three aspects:compressive strength,pore structure and *** addition,the research on restoration surface defects and cracks of cement-based material by microbe cement is introduced from two parameters:surface water absorption and compressive strength recover *** results show that microbe cementitious material can bind loose particles and repair surface defects or cracks of cement-based material.

关键词： microbe cement defects microstructure calcite cracks

Hot Deformation Characteristics for a Nickel-base Superalloy GH742y

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Journal of Materials science & Technology 2009年第3期25卷 373-378页

作者： Fuwei Kang Jianfei Sun Guoqing Zhang Zhou Li school of Material science and engineering Harbin Institute of Technology Harbin 150001 China school of Material science and engineering Harbin University of Science and Technology Harbin 150040 China Beijing Institute of Aeronautical Materials Beijing 100095 China

The hot deformation characteristics of as-cast nickel-base superalloy GH742y after hot isostatic pressing （HIP）（hereafter referred to as-cast alloy） have been investigated by hot compression tests in the temperature range of 1050 to 1140℃, strain rate range of 0.01 s^-1 to 10 s^-1 and strain range of 35% to 50% by means of Gleeble-3500 thermal mechanical simulator. The results show that the as-cast alloy exhibits the poor deformability, and shows wedge-shaped cracking beyond the strain of 35%. At strain rates less than 1.0 s^-1, the stress-strain curves exhibit nearly steady-state behavior, while at strain rate of 10 s^-1, a yield drop and serrated yielding occur. The activation energy values developed on the basis of the experimental data are divided into three domains. The first domain appears at lower strain rate （≤1.0 s^-1） and lower temperature （≤1080℃）, with the lowest mean value of activation energy about 261.4 kJ/mol. The second domain appears at the same strain rate as the first domain, but higher temperature （〉1080℃）, with the intermediate mean value of activation energy about 328.8 k J/tool. The third domain appears at higher strain rate （10 s^-1） and temperature range of 1050 to 1140℃, with the largest mean value of activation energy about 605.05 kJ/mol. Three different constitutive equations are established in corresponding to domains. Microstructural observations in the third domain reveal non-uniform dynamic recrystallization （DRX） of homogeneous γ phase, which leads to the poor deformability and the highest Q value. In contrast, microstructures in the first domain show fully DRX of homogeneous γ phase, leading to the better deformability and the lowest Q value. It is noted that the grain size increases with the increment of strain rate or temperature. These results suggest that bulk metal working of this material may be carried out in the first domain where fully DRX of γ homogeneous occurred.

关键词： Superalloy Hot deformation Constitutive equation Activation energy

Design of equivalent-input-disturbance estimator using a generalized state observer

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控制理论与应用（英文版） 2013年第1期11卷 74-79页

作者： Min WU Kunpeng LOU Fangchun XIAO Ruijuan LIU Yong HE Jinhua SHE school of Information science and engineering Central South University Hunan engineering Laboratory for Advanced Control and Intelligent Automation school of Computer science Tokyo University of Technology

In this paper, we present a design method based on the concept of equivalent input disturbance （EID） to reject disturbances for a linear time-invariant system. A generalized state observer （GSO） is used to estimate an EID of the external disturbances, and the pole-assignment algorithm is employed to select the matrices of the GSO. Simulation and experimental results of a rotational speed control system demonstrate the validity of our method.

关键词： Disturbance estimation Disturbance rejection Equivalent input disturbance Generalized state observer Pole assignment Rotational speed control

Modeling of mechanical behaviors for natural fiber reinforced composites under hygrothermal ageing

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science China(Physics,Mechanics & Astronomy) 2017年第12期60卷 80-82页

作者： Zheng Zhong Fang Tian school of science Harbin Institute of Technology school of Aerospace engineering and Applied Mechanics Tongji University

In recent years,natural fiber reinforced composites have been widely applied to various industrial products for their excellent environmental-friendly *** is essential to understand the mechanical properties of natural fiber reinforced composites under their in-service *** with synthetic fibers,the hydrophilicity of natural fibers could result in a much larger quantity of water absorption from the moisture atmosphere,which would have adverse consequences for the durability of natural fiber reinforced composites[1].The environmental temperature would affect the

关键词： reinforced durability moisture consequences friendly ageing constitutive have hydrolysis deterioration

In-situ synthesis of TiO_2 nanostructures on Ti foil for enhanced and stable photocatalytic performance

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Journal of Materials science & Technology 2019年第4期35卷 615-622页

作者： Ke Wang Baodan Liu Jing Li Xiaoyuan Liu Yang Zhou Xinglai Zhang Xiaoguo Bi Xin Jiang school of Materials science and engineering University of Science and Technology of China Shenyang National Laboratory for Materials science (SYNL) Institute of Metal Research (IMR)Chinese Academy of Sciences (CAS) school of Renewable Energy Shenyang Institute of Engineering

TiO_2 nanostructures with strong interfacial adhesion and diverse morphologies have been in-situ grown on Ti foil substrate through a multiple-step method based on conventional plasma electrolytic oxidation(PEO) technology, hydrothermal reaction and ion exchange process. The PEO process is critical to the formation of TiO_2 seeding layer for the nucleation of Na_2Ti_3O_7 and H_2Ti_3O_7 mediates that are strongly attached to the Ti foil. An ion exchange reaction can finally lead to the formation of H_2Ti_3O_7 nanostructures with diverse morphologies and the calcination process can turn the H_2Ti_3O_7 nanostructures into TiO_2 nanostructures with enhanced crystallinity. The morphology of the TiO_2 nanostructures including nanoparticles(NP), nanowhiskers(NWK), nanowires(NW) and nanosheets(NS) can be easily tailored by controlling the NaOH concentration and reaction time during hydrothermal process. The morphology, composition and optical properties of TiO_2 photocatalysts were analyzed using scanning electron microscope(SEM), X-ray diffraction(XRD), photoluminescence(PL) spectroscopy and UV–vis absorption spectrum. Photocatalytic tests indicate that the TiO_2 nanosheets calcined at 500?C show good crystallization and the best capability of decomposing organic pollutants. The decoration of Ag cocatalyst can further improve the photocatalytic performance of the TiO_2 nanosheets as a result of the enhanced charger separation efficiency. Cyclic photocatalytic test using TiO_2 nanostructures grown on Ti foil substrate demonstrates the superior stability in the photodegradation of organic pollutant, suggesting the promising potential of in-situ growth technology for industrial application.

关键词： Plasma electrolytic oxidation In-situ growth TiO2 Photocatalysis Ag co-catalyst

Preparation and Properties of Guiqi Polysaccharides/Chitosan/Alginate Composite Hydrogel Microspheres

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Journal of Renewable Materials 2019年第12期7卷 1321-1332页

作者： Xiaoliang Zhao Yuting Wang Xiuying Pu Jianzhong Ma Feifan Leng Yonggang Wang Yanling Wang Shuhong Yang Fen Ran Weijie Zhang school of Life science and engineering Lanzhou University of TechnologyLanzhou730050China school of Material science and engineering Lanzhou University of TechnologyLanzhou730050China

A series of the Guiqi polysaccharides/chitosan/alginate composite hydrogel microspheres(GPcM)with different particle sizes were prepared with Guiqi polysaccharides(GP),chitosan(CS)and sodium alginate(Alg).The optimum preparation process was also determined by single factor and orthogonal experiment *** GPcM were characterized by fourier transform infrared spectroscopy(FT-IR),scanning electron microscope(SEM),drug loading efficiency test(LE),encapsulation efficiency test(EE)and in vitro release *** results showed that the Guiqi polysaccharides chitosan hydrogel(GPCH)and sodium alginate hydrogel(SAH)formed a crossover system in *** GPcM have a uniform particle size ranging from 395.1μm to 841.5μ*** drug loading efficiency and encapsulation efficiency of the GPcM were 56.3%and 72.6%,*** bovine serum albumin(BSA)loaded in the GPcM released slowly within 180 *** results suggested that the GPcM may have potential application value in drug sustained and controlled release system.

关键词： Guiqi polysaccharides composite hydrogel microspheres cross-linker drug loading