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Chinese Journal of Chemical engineering 2018年第1期26卷 168-174页

作者： Fatemeh Ahmadi Mohsen Pirdashti Abbas Ali Rostami Chemical engineering Department Faculty of EngineeringShomal University

New liquid-liquid equilibrium data for polyethylene glycol （PEG） 3000 ＋ CHO2K ＋ H20 systems were measured at 298.15 K and pH values of 7.95, 8.40 and 9.98. It was found that an increase in pH caused the binodal curve to be displaced downward and the two-phase region to expand. Accordingly, the binodal curve was adjusted to the Pirdashti equation and the tie-line compositions were correlated using the Othmer-Tobias, Bancroft and Hand equations. The study measured the refractive index and densities of several homogeneous binary and ternary solutions. The solutions were used for calibration within a range of 0% to 30% of the mass of the PEG and potassium formate. The density and refractive index data show a linear variation with the mass fraction of the polymer and the salt. The effect of pH on the binodal, tie-line lengths （TLL） and slope of the tie-line （STL） in the systems was exam- ined. It was found that an increase in pH increased the TLL and decreased the STL It was observed that the density of the aqueous two-phase system was influenced by the TLL The difference in density between phases （△p） increased as the TLL and pH increased. It was found that the TLL and Ap showed a linear relationship. The effective excluded volume （EEV） of the PEG was obtained and it was found that EEV also increased as the pH increased.

关键词： Liquid-liquid equilibrium data Density Polyethylene glycol Potassium formate

Evaluation of solvent-mediated phase transformation of glycine using oleic acid: Morphology and characterization study

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Chinese Journal of Chemical engineering 2018年第9期26卷 1829-1836页

作者： Sevgi Polat Perviz Sayan Department of Chemical engineering Faculty of Engineering Marmara University

The polymorphic phase transformation of β-glycine to α-glycine was carried out both in the absence and presence of various concentrations of oleic acid used as additive at 25 ℃ in a water/ethanol medium. The effects of oleic acid and its concentration on phase transformation time were determined by continuously measuring the ultrasonic velocity. The crystals obtained by the completion of the phase transformation were characterized by XRD, SEM, and TG/DTG. The XRD and SEM results indicated that oleic acid significantly impacted phase transformation time and the morphological characteristics of the crystals. In addition to SEM analysis, detailed crystal shape analysis was performed and the circularity, elongation, and convexity parameters were determined quantitatively. TG/DTG analyses were performed to investigate thermal decomposition behavior and to calculate the activation energies based on different kinetic models such as FWO, KAS, Starink, and Tang kinetic models. With the addition of oleic acid to the medium, the calculated activation energy values increased from 89.63–90.63 to153.8–155.4 kJ·mol^（-1）. The activation energy values showed that oleic acid was adsorbed on the crystal surface;this result was supported by FTIR, elemental, and Kjeldahl analyses.

关键词： Glycine Oleic acid Crystallization Isoconversional methods Phase transformation

Optimization of Manganese and Magnesium Contents in As-cast Aluminum-Zinc-Indium Alloy as Sacrificial Anode

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Journal of Materials Science & Technology 2011年第9期27卷 785-792页

作者： Mohammad R. Saeri Ahmad Keyvani Materials engineering Division Faculty of Engineering Shahrekord University

In this study, effects of manganese and magnesium content on the electrochemical properties of Al-Zn-ln sacrificial anode were studied in 0.5 mol/L NaCl solution （pH=5）. The aluminum base alloy with different amounts of Mn and Mg were melted at 750℃, then casted at molds at 25℃. Corrosion experiments were mounted to determine the optimal effect of Mn and Mg on the efficiencies of the aluminum alloy anodes. The corroded and unexposed sample surfaces were subjected to microstructure characterization by optical and scanning electron microscopy. AI-Zn-ln alloy doped with 0%, 0.01%, 0.05%.0.2% and 0.3% by weights of Mn and 0%, 0.5%, 1.0%, 1.5%, 2.0%, 2.5% and 3.0% by weights of Mg were prepared to determine the effect of Mn and Mg on anode efficiency in the environment. The different microstructures of the evolved AI- Zn-ln-Mg-Mn alloy were correlated with the anode efficiencies. The Al-5.0%Zn-2.0%Mg-0.15%Mn-0.02%ln gave the best anode efficiency （about 83%）. The microstructures of the corroded surface of the optimized alloy revealed decreased distribution of the pockets of localized attacks which are characteristics of pitting （or crevice） corrosion.

关键词： Corrosion Aluminum alloy Sacrificial anode Manganese Magnesium Current capacity

ELECTROSPINNING OF CYCLODEXTRIN FUNCTIONALIZED CHITOSAN/PVA NANOFIBERS AS A DRUG DELIVERY SYSTEM

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Chinese Journal of Polymer Science 2013年第10期31卷 1343-1351页

作者： Maryam Bazhban Mahdi Nouri Javad Mokhtari Department of Textile engineering Faculty of Engineering University of Guilan

A new type ofnanofibrous structure from chitosan bearing carboxymethyl-β-cyclodextrin （cs-g-β-CD） as a novel drug delivery system was synthesized by grafting carboxymethyl-β-cyclodextrin （CM β-CD） onto chitosan （cs） in the presence of water soluble 1-ethyl-3-（3-dimethylaminopropyl） carbodiimide （EDC） as the condensing agent and N-hydroxysuccinimide （NHS）. Defect free mats containing cs-g-β-CD have been fabricated using electrospirming of an aqueous solution of poly（vinyl alcohol）（PVA）/cs-g-β-CD blends. The morphology and diameter of the electrospun nanofibers were examined by scanning electron microscopy （SEM）. The average fiber diameter was in the range of 130-210 run. SEM images showed that the morphology and diameter of the nanofibers were mainly affected by weight ratio of the blend at constant applied voltage. The results revealed that increasing cs-g-β-CD content in the blends decreases the average fiber diameter. It was observed that the PVA/cs-g-β-CD nanofibrous mat provided a slower release of the entrapped drug in compare to PVA/cs nanofibrous mat.

关键词： Chitosan βcyclodextrin Nanofibers Drug delivery.

Chemical equilibrium constants of rare earth nitrates and tri-n-butyl phosphate complex formation

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Journal of Rare Earths 2011年第9期29卷 896-901页

作者： Kalaya Changkrueng Deacha Chatsiriwech Department of Chemical engineering Faculty of Engineering Chulalongkorn University

Mixed rare earth nitrates （REi（NO3）3） in the aqueous solution was mixed with tri-n-butyl phosphate （TBP, （n-C4H9O）3PO） dissolved in kerosene for the formation of their corresponding complexes （REi（NO3）3·ni（n-C4H9O）3PO） at 303 K. The effects of initial concentrations of both TBP and mixed rare earth nitrates on the equilibrium constants of their complex formations were investigated. The complexes were formed almost immediately after mixing. The simultaneous formations reached their chemical equilibria within a few minutes by shaking the mixture at 200 r/min. The chemical equilibrium constants of the complex formations were independent of the initial TBP concentrations. However, they were decreased by reducing the concentration of REi（NO3）3. All equilibrium constants of the simultaneous complex formations were less than 0.7, while the average molar ratio of TBP to REi（NO3）3 of the complexes varied between 1.0 and 1.6. The chemical equilibrium constant for the formation of La（NO3）3·（n-C4H9O）3PO was 0.09, while that of Dy（NO3）3·（n-C4H9O）3PO was 0.68. The ascending sequence of chemical equilibrium constants for the simultaneous formations was La, Ce, Pr, Nd, Eu, Y, Sm, Gd, and Dy.

关键词： chemical equilibrium constants TBP rare earth nitrates complex formation

Design factors affecting the dynamic performance of soil suspension in an agitated, baffled tank

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Chinese Journal of Chemical engineering 2016年第12期24卷 1664-1673页

作者： M.Moayeri Kashani S.H.Lai S.Ibrahim P.Moradi Bargani Department of Civil engineering Faculty of Engineering University of Malaya

The effects of particle size, impeller clearance and impeller speed are assessed to show how condition variations influence power consumption in the water-solid slurry suspension in an agitated tank. The energy efficiency of slurry height variation, impeller type and diameter, and solid movement speed has been investigated with six soil series stirred in a soil-water slurry. Coarser sand particles are observed to significantly increase power consumption, while finer particles, for instance clay, decrease the stirring power requirement. The 3-blade HR100 SUPERMIX? impeller manufactured by SATAKE generally performs more efficiently than a conventional4-pitched blade turbine. The impeller's geometric design, including diameter and number of blades influences the impeller's energy efficiency, and HR100 impellers with greater diameters remarkably reduce power consumption. The tests demonstrated that the power required to provide off-bottom solid suspension and solid dispersion can be reduced dramatically by increasing the slurry height rather than by accelerating the impeller, if this option is possible.

关键词： Energy efficiency Stirred tank Water-solid slurry Mixing Solid suspension Impeller geometry

Static and dynamic responses of a microcantilever with a T-shaped tip mass to an electrostatic actuation

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Acta Mechanica Sinica 2016年第6期32卷 1104-1122页

作者： B.Firouzi M.Zamanian S.A.A.Hosseini Department of Mechanical engineering Faculty of Engineering Kharazmi University

In this study, nonlinear static and dynamic responses of a microcantilever with a T-shaped tip mass excited by electrostatic actuations are investigated. The electrostatic force is generated by applying an electric voltage between the horizontal part of T-shaped tip mass and an opposite electrode plate. The cantilever microbeam is modeled as an Euler-Bernoulli beam. The T-shaped tip mass is assumed to be a rigid body and the nonlinear effect of electrostatic force is considered. An equation of motion and its associated boundary conditions are derived by the aid of combining the Hamilton principle and Newton’s method. An exact solution is obtained for static deflection and mode shape of vibration around the static position. The differential equation of nonlinear vibration around the static position is discretized using the Galerkin method. The system mode shapes are used as its related comparison functions. The discretized equations are solved by the perturbation theory in the neighborhood of primary and subharmonic resonances. In addition, effects of mass inertia, mass moment of inertia as well as rotation of the T-shaped mass, which were ignored in previous works, are considered in the analysis. It is shown that by increasing the length of the horizontal part of the T-shaped mass, the amount of static deflection increases, natural frequency decreases and nonlinear shift of the resonance frequency increases. It is concluded that attaching an electrode plate with a T-shaped configuration to the end of the cantilever microbeam results in a configuration with larger pull-in voltage and smaller nonlinear shift of the resonance frequency compared to the configuration in which the electrode plate is directly attached to it.

关键词： MEMS Electrostatic Static deflection Natural frequency Pull-in voltage Perturbation theory T-shaped mass Primary and subharmonic resonances

A note on the surface motion of a semi-cylindrical canyon for incident cylindrical SH waves radiated by a finite fault

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Earthquake engineering and engineering Vibration 2016年第3期15卷 445-455页

作者： Reza S.Jalali Zaniar Tokmechi Department of Civil engineering Faculty of Engineering University of Guilan

The plane-wave assumption for incident SH waves can be a good approximation for cylindrical and spherical waves radiated from finite sources, even when the source is as close as twice the size of the inhomogeneity, and when the source and the inhomogeneity are described within the same coordinate system. However, in a more general setting, and when the fault＇s radiation pattern must be considered, the plane-wave approximation may not yield satisfactory answers for arbitrary orientation of the fault. Jalali et al. （2015） demonstrated this for a semi-cylindrical, sedimentary valley, and in this study we extend their results to a case in which the semi-circular, sedimentary valley is replaced by a canyon. We describe the effects of incident cylindrical waves on the amplitudes of surface motion in and near the semi-cylindrical canyon when the causative faults are at different distances and have different curvatures and orientations.

关键词： plane SH waves cylindrical SH waves effects of arbitrary fault orientation on amplification of surfacemotions

Smart Semi-active PID-ACO control strategy for tower vibration reduction in Wind Turbines with MR damper

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Earthquake engineering and engineering Vibration 2019年第4期18卷 887-902页

作者： Mahmudur Rahman Zhi Chao Ong Wen Tong Chong Sabariah Julai Department of Mechanical engineering Faculty of Engineering University of Malaya

Wind turbine technology is well known around the globe as an eco-friendly and eff ective renewable power source. However, this technology often faces reliability problems due to structural vibration. This study proposes a smart semi-active vibration control system using Magnetorheological (MR) dampers where feedback controllers are optimized with nature-inspired algorithms. Proportional integral derivative (PID) and Proportional integral (PI) controllers are designed to achieve the optimal desired force and current input for MR the damper. PID control parameters are optimized using an Ant colony optimization (ACO) algorithm. The eff ectiveness of the ACO algorithm is validated by comparing its performance with Ziegler-Nichols (Z-N) and particle swarm optimization (PSO). The placement of the MR damper on the tower is also investigated to ensure structural balance and optimal desired force from the MR damper. The simulation results show that the proposed semi-active PID-ACO control strategy can signifi cantly reduce vibration on the wind turbine tower under diff erent frequencies (i.e., 67%, 73%, 79% and 34.4% at 2 Hz, 3 Hz, 4.6 Hz and 6 Hz, respectively) and amplitudes (i.e. 50%, 58% and 67% for 50 N, 80 N, and 100 N, respectively). In this study, the simulation model is validated with an experimental study in terms of natural frequency, mode shape and uncontrolled response at the 1st mode. The proposed PID-ACO control strategy and optimal MR damper position is also implemented on a lab-scaled wind turbine tower model. The results show that the vibration reduction rate is 66% and 73% in the experimental and simulation study, respectively, at the 1st mode.

关键词： ant colony optimization fi nite diff erence method magnetorheological damper PID-ACO controller semiactive control system identifi cation wind turbine tower

Assessment of deterioration in RHA-concrete due to magnesium sulphate attack

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International Journal of Minerals,Metallurgy and Materials 2010年第6期17卷 691-696页

作者： G.A. Habeeb H.B. Mahmud N.B.A.A. Hamid Department of Civil engineering Faculty of Engineering University of Malaya

The assessment of magnesium sulphate attack on concretes containing rice husk ash （RHA, 20wt% of the cementitious materials） with various average particle sizes was investigated. The total cementitious materials were 390 kg and the water-to-binder ratio （W/B） was 0.53 for all mixtures. Specimens were initially cured in water for 7 d and then immersed in the 3wt% magnesium sulphate solution for up to 111 d of exposure. The specimens were subjected to drying-wetting cycles to accelerate sulphate attack. In addition to the visual monitoring of the specimens, the concrete specimens were subsequently tested for compressive strength, dynamic modulus of elasticity, and length and mass changes. The results show that the specimens exposed to sulphate attack exhibit higher strength and dynamic modulus than those kept in water. The length change is negligible and can be attributed to the normal swelling of concrete. On the other hand, concretes suffers mass loss and surface spalling and softening; the fine RHA-concrete results in a better resistance. For the accelerated sulphate attack method used in this study, mass change and visual monitoring are recommended for assessing the deterioration degree and the effectiveness of supplementary cementitious materials to resist sulphate attack.

关键词： concretes pozzolan ettringite rice husk ash (RHA) magnesium sulphate