Carbon-based novel sorbent for removing gas-phase mercury

The purpose of the present study is to develop a carbon-based sorbent for removing gaseous mercury. Existing commercial activated carbon for removing mercury is superior in efficiency but expensive. This study attempted to develop a cost-effective sorbent using petroleum coke, which is low-priced carbon source. It took note that the sulfur content of domestic petroleum coke is around 7%. Sulfur is a superior reaction material in removing mercury and it has been usually impregnated into activated carbon for use. Sulfur in petroleum coke is strongly stuck to carbon matrix, so it is not reactive as itself. This study applied high-temperature pyrolysis to petroleum coke to make its sulfur take out of the surface of the petroleum coke and used the sulfur in removing mercury. According to the result of the experiment, the specific surface area of petroleum coke increased around 10 times in the course of pyrolysis and the efficiency of mercury removal was significantly improved as part of sulfur taken out. Thus, pyrolyzed petroleum coke was considered to have high potential as a sorbent for removing mercury.     

Model-based reference trajectory generation for tip-based learning controller

The non-minimum phase characteristic of a flexible manipulator makes tracking control of its tip difficult The level of the tip tracking performance of a flexible manipulator is significantly affected by the characteristics of the tip reference trajectory as well as the characteristics of the flexible manipulator system This paper addresses the question of how to best specify a reference trajectory for the tip of a flexible mampulator to follow in order to achieve the objectives of reducing tip tracking error, residual tip vibration, and the required actuation effort at the manipulator joint A novel method of tip-based learning controller for the flexible manipulator system is proposed in the paper, where a model of the flexible manipulator system with a command shaping filter is used to generate a smooth and realizable tip reference trajectory for a tip-based learning controller     

Design of a curved stabilizer with damping orifices for reducing axial run-out of flexible optical disks

The idea of a curved stabilizer with damping orifices is applied to the high speed rotating flexible optical disk system in order to reduce the disk deflection and the axial run-out of the disk. A track of orifices is drilled along the edge of a curved annular stabilizer. The effects of the diameter and length of each orifice, number of orifices, and radial position of the orifices on the reduction of axial run-out of the disk are investigated experimentally together with the effects of the inner radius for the air flow, initial gap height, and rotational speed. The experimental results showed that the curved stabilizer with orifices can reduce the axial run-out of the disk at 10,000?rpm within 10???m over the entire span of the disk.     

Physical‐Mechanical Properties of Agar/κ‐Carrageenan Blend Film and Derived Clay Nanocomposite Film

Abstract: Binary blend films with different mixing ratio of agar and κ‐carrageenan were prepared using a solution casting method with and without nanoclay and the effect of their composition on the mechanical, water vapor barrier, and water resistance properties was tested. The tensile strength (TS) of the κ‐carrageenan film was greater than that of agar film. The water vapor permeability (WVP) of the agar film was lower than that of κ‐carrageenan film, the swelling ratio (SR) and water solubility (WS) of κ‐carrageenan film were higher than those of agar film. Each property of the binary blend films varied proportionately depending on the mixing ratio of each component. The XRD result indicated that the nanocomposite with agar/κ‐carrageenan/clay (Cloisite^® Na⁺) was intercalated. Consequently, the mechanical strength, water vapor barrier properties, and water contact angle (CA) were significantly (P < 0.05) improved through nanocomposite formation.     

Preparation and characterization of agar/silver nanoparticles composite films with antimicrobial activity

Composite films with silver nanoparticles (AgNPs), obtained by reduction of AgNO₃ using an environmentally friendly method (combined reduction of AgNO₃ by trisodium citrate solution and heating), and agar as a polymer matrix and a capping agent were prepared by solvent casting method. The surface color of the resulting agar/AgNPs films exhibited the characteristic plasmonic effect of the silver nanoparticles, and the characteristic properties of the composite films were greatly influenced by changing the concentration of AgNPs added. Significant increase in water vapor barrier properties and surface hydrophobicity were observed with increase in the concentration of AgNPs without reduction in the mechanical strength. In addition, the agar/AgNPs films loaded with more than 1 wt% of silver nanoparticles exhibited strong antimicrobial activity against both Gram-positive (Listeria monocytogenes) and Gram-negative (Escherichia coli O157:H7) bacterial pathogens.     

Kinetics of the Au-Ni-Sn ternary intermetallic layer redeposition at the solder/under-bump metallurgy interface during aging treatment

The Au-Ni-Sn ternary intermetallic layer redeposition at the interface between the solder and the Au/Ni/Cu under-bump metallurgy (UBM) was measured experimentally and analyzed theoretically. The predicted thicknesses of the layer, assuming Au diffusion in the Sn-3.5Ag solder matrix, were thicker than those measured experimentally. The thicknesses predicted in the Sn-37Pb solder matrix, on the other hand, were thinner than those measured experimentally. The discrepancies between the predicted and measured thicknesses were discussed based on findings, such as formation of the ternary phase and presence of AuSn₄ depletion zones in the solder matrices, and the stoichiometry of the ternary phase.     

Selective opioid agonists modulate afferent transmission in the rat nucleus tractus solitarius

We examined the effects of agonists at mu, delta and kappa opioid receptors on neurons located in the nucleus tractus solitarius of the rat using whole-cell patch-clamp recordings in brainstem slices. The mu selective opioid agonist DAMGO hyperpolarized most neurons tested. This effect was associated with the activation of a K(+)-conductance. The effect of DAMGO tended to desensitize and was blocked by naloxone. Dynorphin A also produced this effect. However, the kappa-1-selective opioid agonist U-69593 and two delta-selective opioid agonists did not. DAMGO also depressed glutamate-mediated excitatory postsynaptic potentials and GABA-mediated evoked by stimulation of the tractus solitarius. Dynorphin A, U-69593 and delta-opioid agonists also reduced the excitatory postsynaptic potential, although they were less effective than DAMGO. The presynaptic inhibitory effects of DAMGO were also blocked by naloxone, but did not desensitize. These actions may help to explain the ability of opiates to modulate a variety of autonomic reflexes.     

Water vapor adsorption isotherms of agar-based nanocomposite films

Adsorption isotherms of agar and agar/clay nanocomposite films prepared with different types of nanoclays, that is, a natural montmorillonite (Cloisite Na(+) ) and 2 organically modified montmorillonites (Cloisite 30B and Cloisite 20A), were determined at 3 different temperatures (10, 25, and 40 °C). The water vapor adsorption behavior of the nanocomposite films was found to be greatly influenced with the type of clay. The Guggenheim-Anderson-de Boer (GAB) isotherm model parameters were estimated by using both polynomial regression and nonlinear regression methods and it was found that the GAB model fitted adequately for describing experimental adsorption isotherm data for the film samples. The monolayer moisture content (m(o) ) of the film samples was also greatly affected by the type of nanoclay used, that is, m(o) of nanocomposite films was significantly lower than that of the neat agar film. Nanocomposite films prepared with hydrophobic nanoclays (Cloisite 30B and Cloisite 20A) exhibited lower m(o) values than those prepared with hydrophilic nanoclay (Cloisite Na(+) ).