Solubilization and micellarenhanced ultrafiltration ofo-cresol by Sodium Dodecyl Sulfate Micelles

The solubilization and the micellar-enhanced ultrafiltration (MEUF) of o-cresol were investigated by using an anionic surfactant, sodium dodecyl sulfate (SDS). In order to study the solubilization behaviour of the solute, the semiequilibrium dialysis (SED) method was employed and stirred-cell ultrafiltration experiments were performed for the test of MEUF. The analysis of the results supported that approximately two surfactant molecules provide a location for the solubilized solute within micelle. In the removal of o-cresol by MEUF, as long as high SDS concentrations in the retentate (>0.2 M) are avoided, relatively good rejection of o-cresol (85 %) could be obtained under the conditions used (initial concentration ratio:[o-cresol]/[SDS]=0.2 and 0.6). Furthermore, the ultrafiltration processes were nearly at equilibrium, so that the permeate concentrations of o-cresol could be predicted from the SED results. The separation efficiency was greater at lower o-cresol concentrations when the SDS concentrations were fixed in the feed, while the rejection increased with increasing the SDS concentrations at constant intramicellar mole fraction of the solute Xc. In addition, as the o-cresol loading of retentate increased, the less SDS in the retentate permeated through ultrafiltration membranes. On the other hand, the higher o-cresol loadings reduced the fluxes of MEUF runs.     

Universal integral controllers with non-linear integral gains

We consider a single-input single-output minimum-phase non-linear system which has a normal form. In previous work, integral control and high-gain observers were used to achieve robust regulation under output feedback. To improve the transient performance, we propose the use of integrators with non-linear gains. We prove that the controller achieves regional and semiglobal regulation. Simulation results are presented showing the improved overshoot and settling time.     

Characterization of non-stoichiometric Ga2O3-x thin films grown by radio-frequency powder sputtering

We report the synthesis and characterization of non-stoichiometric Ga₂O_3-x thin films deposited on sapphire (0001) substrates by radio-frequency powder sputtering. The chemical and electronic states of the non-stoichiometric Ga₂O_3-x thin films were investigated. By sputtering in an Ar atmosphere, the as-grown thin films become non-stoichiometric Ga₂O_2.7, due to the difference in sputtering yield between Ga and O species of the Ga₂O₃ target. The electronic states of the thin films consist of ~85% Ga³⁺ and ~15% Ga¹⁺, corresponding to Ga₂O₃ and Ga₂O, respectively. The films have the electrical characteristics of a semiconductor, with electrical conductivity of approximately 5.0 × 10^-4 S cm^-1 and a carrier concentration of 4.5 × 10¹⁴ cm^-3 at 300 K.     

Protection of MPEG‐2 Multicast Streaming in an IP Set‐Top Box Environment

The widespread use of the Internet has led to the problem of intellectual property and copyright infringement. Digital rights management (DRM) technologies have been developed to protect digital content items. Digital content can be classified into static content (for example, text or media files) and dynamic content (for example, VOD or multicast streams). This paper deals with the protection of a multicast stream on set‐top boxes connected to an IP network. In this paper, we examine the following design and architectural issues to be considered when applying DRM functions to multicast streaming service environments: transparent streaming service and large‐scale user environments. To address the transparency issue, we introduce a ‘selective encryption scheme'. To address the second issue, a ‘key packet insertion scheme’ and ‘hierarchical key management scheme’ are introduced. Based on the above design and architecture, we developed a prototype of a multicasting DRM system. The analysis of our implementation shows that it supports transparent and scalable DRM multicasting service in a large‐scale user environment.     

Dependence of the electrocatalytic performance of platinized counter electrodes on the redox mediator employed in dye-sensitized solar cells

The electrocatalytic properties of platinized counter electrodes (Pt CEs) prepared by various coating methods were investigated with respect to the redox mediator, including the widely used iodide/tri-iodide (I^?/I ₃ ^? ) and the more recently introduced cobalt(II/III)tris(2,2′-bipyridine) (Co(bpy) ₃ ^2+/3+ ), for application in dye-sensitized solar cells (DSCs). The coating methods controlled Pt loading and the surface morphology of the Pt CEs. For a high-performance DSC with a fill factor >0.7, the charge-transfer resistance at the Pt CE/electrolyte interface should be <4.5 Ω cm² for both redox mediators. The I^?/I ₃ ^? -mediated DSCs were insensitive to Pt loading as low as 0.001 mg cm^?2, while the Co(bpy) ₃ ^2+/3+ -mediated DSCs required relatively large Pt loadings of > 0.005 mg cm^?2. Our results indicated that care should be taken in the preparation of Pt CEs with high transparency and low loading to obtain high-performance DSCs employing cobalt–ligand redox electrolyte.     

Quality Enhancement for Hybrid 3DTV with Mixed Resolution Using Conditional Replenishment Algorithm

This paper proposes a conditional replenishment algorithm (CRA) to improve the visual quality (where spatial resolutions of the left and right views are mismatched) of a hybrid stereoscopic 3DTV that is based on the ATSC‐M/H standard. So as to generate an enhanced view, the CRA is to choose the better substitute among a disparity‐compensated view with high quality and a simply interpolated view. The CRA generates a disparity map that includes modes and disparity vectors as additional information. It also employs a quad‐tree structure with variable block size by considering the spatial correlation of disparity vectors. In addition, it takes advantage of the disparity map used in a previous frame to keep the amount of additional information as small as possible. The simulation results show that the proposed CRA can successfully improve the peak signal‐to‐noise ratio of a poor‐quality view and consequently have a positive effect on the subjective quality of the resulting 3D view.     

Optimal Routing in Two Parallel Queues with Exponential Service Times

In this paper we investigate the problem of the effective computation of the optimal routing sequence in a queuing system made of two parallel queues with exponential service times. We first show that the optimal policy (minimizing the expected waiting time) is a Sturmian sequence and we establish several qualitative properties of this policy (monotonicity, continuity, convexity). Then, we propose an algorithm to compute the optimal routing sequence efficiently. We address the issues of time complexity as well as numerical stability of this algorithm. We then run an extensive set of experiments which show several interesting features of the optimal policy with apparent discontinuities and a fractal behavior and we provide several good approximations by using fast heuristics.     

Full-Body Compliant Human–Humanoid Interaction: Balancing in the Presence of Unknown External Forces

This paper proposes an effective framework of human-humanoid robot physical interaction. Its key component is a new control technique for full-body balancing in the presence of external forces, which is presented and then validated empirically. We have adopted an integrated system approach to develop humanoid robots. Herein, we describe the importance of replicating human-like capabilities and responses during human-robot interaction in this context. Our balancing controller provides gravity compensation, making the robot passive and thereby facilitating safe physical interactions. The method operates by setting an appropriate ground reaction force and transforming these forces into full-body joint torques. It handles an arbitrary number of force interaction points on the robot. It does not require force measurement at interested contact points. It requires neither inverse kinematics nor inverse dynamics. It can adapt to uneven ground surfaces. It operates as a force control process, and can therefore, accommodate simultaneous control processes using force-, velocity-, or position-based control. Forces are distributed over supporting contact points in an optimal manner. Joint redundancy is resolved by damping injection in the context of passivity. We present various force interaction experiments using our full-sized bipedal humanoid platform, including compliant balance, even when affected by unknown external forces, which demonstrates the effectiveness of the method.