SYNTHESIS AND CHARACTERIZATION OF CADMIUM SULFIDE NANOPARTICLE–LOADED ACTIVATED CARBON AS A NOVEL ADSORBENT FOR EFFICIENT REMOVAL OF REACTIVE ORANGE 12

The objective of this study was to evaluate the adsorption potential of cadmium sulfide nanoparticle–loaded activated carbon (CdSN-AC) for removal of reactive orange 12 (RO-12) dyestuffs from aqueous solutions. The characterization of CdSN-AC was performed by X-ray diffraction (XRD), transmission electron microscopy (TEM), and field emission scanning electron microscopy (FESEM) techniques. The effects of experimental parameters such as initial solution pH, contact time, initial RO-12 concentration, amount of CdSN-AC, and temperature on the adsorption process were evaluated in detail. The kinetic studies indicated that the adsorption process was best described by the pseudo-second-order kinetics model. The experimental data were analyzed by the Langmuir, Freundlich, and Tempkin isotherm models, and the monolayer adsorption capacity of CdSN-AC was found to be 150.0 mg g^?1 by using the Langmuir isotherm model. The thermodynamic parameters indicated that the adsorption of RO-12 onto CdSN-AC was feasible, spontaneous, and endothermic in nature.     

Transient liquid phase bonding of 304 stainless steel using a Co-based interlayer

Transient liquid phase bonding of AISI 304 austenitic stainless steel was carried out using a Co-based interlayer with 40?μm thickness. The effect of bonding time and solid-state homogenisation time on the microstructure and mechanical properties of samples was investigated. The results showed that isothermal solidification was completed within 30?min at a constant temperature of 1180°C. With increasing homogenisation time, at 1000°C, a more uniform distribution of alloying elements and hardness profile across the joint region was achieved. The average shear strength of homogenised samples was about 72% that of the base metal at the same heat treatment cycle.     

Stability analysis of an electrostatically actuated out of plane MEMS structure

In the present research, stability and static analyses of microelectromechanical systems microstructure were investigated by presenting an out-of-plane structure for a lumped mass. The presented model consists of two stationary electrodes in the same plane along with a flexible electrode above and in the middle of the two electrodes. The nonlinear electrostatic force was valuated via numerical methods implemented in COMSOL software where three-dimensional simulations were performed for different gaps. The obtained numerical results were compared to those of previous research works, indicating a good agreement. Continuing with the research, curves of electrostatic and spring forces were demonstrated for different scenarios, with the intersection points (i.e., equilibrium points) further plotted. Also drawn were plots of deflection versus voltage for different cases and phase and time history curves for different values of applied voltage followed by introducing and explaining pull-in and pull-out snap-through voltages in the system for a specific design. It is worth noting that, at voltages between the pull-in and pull-out snap-through voltages, the system was in bi-stable state. Based on the obtained results, it was observed that the gap between the two electrodes and the applied voltage play significant roles in the number and type of the equilibrium points of the system.

     

On the general Kalman filter for discrete time stochastic fractional systems

In this paper the derivation of Kalman filter for discrete time-stochastic fractional system is investigated. Based on a novel cumulative vector form model for fractional systems, a general Kalman filter is introduced. The validity of the proposed method has been compared with a previously presented method via simulation results. It is shown that this method can be better applied for discrete time stochastic fractional systems with slower dynamics.     

Closed-Form Model and Parametric Study on Connection of Concrete-Filled FRP Tubes to Concrete Footings by Direct Embedment

Concrete-filled fiber-reinforced polymer (FRP) tubes (CFFTs) have been introduced as a new system for piles, columns, and poles. A simple moment connection based on direct embedment of the CFFT into concrete footings or pile caps, without using dowel-bar reinforcement, has been proposed by the authors. Robust analytical models to predict the critical embedment length (Xcr) were also developed and experimentally validated. In this paper, a comprehensive parametric study is carried out using the models developed earlier along with a newly developed closed-form model for the general case of axial loading, bending, and shear applied to the CFFT member. The parameters studied are the diameter (D), thickness (t), length outside the footing (L), and laminate structure of the FRP tube, as well as the tube-concrete interface bond strength (τmax?), concrete compressive strength in the CFFT (fct′) and footing (fc′), and the magnitude and eccentricity of axial compressive or tensile loads. It was shown that increasing D, L/D, τmax?, and fc′ of the footing, or the axial compression load, reduces (X/D)cr, whereas increasing t and fct′ of the CFFT, the fraction of longitudinal fibers in the tube, or the axial tension load, increases Xcr. As the axial load eccentricity increases, Xcr reduces for tension loads and increases for compression loads until both cases converge asymptotically to the same Xcr value, essentially that of pure bending.     

A theoretic framework for intelligent expert systems in medical encounter evaluation

Abstract: This paper describes a novel approach to implementation of a medical diagnosis expert system that can assist physicians with their daily practices. Differential artificial intelligence techniques are incorporated into a multi-stage expert system to best represent the various phases of the patient diagnosis process. A weighted scoring system is used to represent the subjective analysis stage, while a rule-based fuzzy expert system is employed to both interpret laboratory tests and imaging findings and suggest the final diagnosis. A model of various patient flow scenarios is presented to demonstrate the functionality of the proposed expert system. An actual example of patient walkthrough is used to demonstrate various computation steps from recording the patient chief complaint to arriving at the final diagnosis. It is shown that the conclusion arrived at by using the proposed system is consistent with a common diagnosis of a third party specialist who is asked to evaluate the performance of the system.     

Modelling Scenarios to Estimate the Potential Impact of Hydrological Standards on Nutrient Retention in the Tobacco Creek Watershed,Manitoba, Canada

Nutrient loading from agricultural drainage systems into downstream aquatic ecosystems, like Lake Winnipeg in the prairie province of Manitoba, Canada, represents a major challenge for water quality management. In order to improve water quality in downstream waterbodies, the Manitoba government is currently investigating the relationship between hydrological standard of agricultural drainage network and nutrient retention in the drainage systems. Briefly, oversized drains have more capacity to transport nutrients, which can increase nutrient loading to downstream waterbodies, especially during rainfall events. Currently, the hydrological standards of agricultural drainage design in Manitoba were mainly developed according to cost-benefit analysis without considering nutrient retention. The purpose of this study was to use computer modelling techniques to simulate the impact of drain size (based on different hydrological standards) on nutrient retention within an agricultural drainage network. The site chosen was the Tobacco Creek Watershed, an agricultural area which drains into the Red River, and thence into Lake Winnipeg. Suspended sediment, nutrient and flow data, from several locations along the Brown drain within this watershed, were used to calibrate a water quality model. Scenarios were then simulated with the model to estimate how different drain sizes affect nutrient transport and retention. Sampling took place during the spring and summer of 2013 starting with freshet and ending when the drains dried up near mid-summer. Study results indicated that the amount of nutrients transported was generally greater during freshet and summer rain storms. Occasionally, however, nutrients in summer discharge exceeded those transported during freshet. The water quality model was applied to the Brown drain to investigate the effects of different drain sizes for rainfall amounts under 2, 5, 10, 15, and 20 year return periods. Generally the results indicate that as the return periods became larger (in larger channels) lower nutrients concentrations were predicted downstream (higher decay rates). On average, the model predicted a 15%–20% decline in nutrient concentration with a 20-year return channel design compared to a 2-year return. The research from this study may provide an impetus to the policy-making process of drainage design.     

碳纳米管表面涂覆钛的新方法(英文)

采用TiCl4水解法对表面酸功能化的碳纳米管(CNTs)进行TiO2涂层,然后通过程序升温还原(TPR),使TiO2涂层转变为Ti涂层。利用SEM、TEM、XRD和EDAX对CNTs、CNT/TiO2纳米复合材料和Ti涂层CNTs进行表征。结果表明:超声波酸功能化CNTs后,可将TiO2成功地涂覆于CNTs表面;在850℃下、H2/Ar氛围中,通过TPR可将TiO2涂层还原为金属Ti涂层。该Ti涂层对CNTs和其他金属形成复合材料非常重要。