On emulated nonlinear reduced-order observers for networked control systems

We consider a general class of nonlinear reduced-order observers and show that the global asymptotic convergence of the observation error in the absence of network-induced constraints is maintained for the emulated observer semiglobally and practically (with respect to the maximum allowable transmission interval) when system measurements are sent through a communication channel. Networks governed by a Lyapunov uniformly globally asymptotically stable protocol are investigated. Our results can be used to synthesize various observers for networked control systems for a range of network configurations, as we illustrate it by considering classes of immersion and invariance observers which include the circle-criterion observers.     

Improving code completion with program history

Code completion is a widely used productivity tool. It takes away the burden of remembering and typing the exact names of methods or classes: As a developer starts typing a name, it provides a progressively refined list of candidates matching the name. However, the candidate list usually comes in alphabetic order, i.e., the environment is only second-guessing the name based on pattern matching, relying on human intervention to pick the correct one. Finding the correct candidate can thus be cumbersome or slower than typing the full name.     

Predicting the phase equilibria of synthetic petroleum fluids with the PPR78 approach

The PPR78 approach is a group contribution‐based thermodynamic model which combines at constant packing fraction the Peng–Robinson equation of state and a Van Laar‐type g^E model. This article demonstrates that, using classical mixing rules (linear on b and quadratic on a), the PPR78 model may also be seen as a group contribution method for the estimation of the temperature‐dependent k_ij of the widely used PR EoS. Our model is endowed of 15 groups and it is possible to predict the k_ij for any mixture containing alkanes, aromatics, naphthenes, CO₂, N₂, H₂S, and mercaptans. This study exhibits the capability of this approach to predict the phase behavior of synthetic petroleum fluids containing components of different volatilities. The many comparisons between calculated and experimental data on natural gases, crude oils, and gas condensates allow concluding that the PPR78 approach is a successful model for phase equilibria calculations of this kind of mixtures. © 2010 American Institute of Chemical Engineers AIChE J, 2010     

Engineering functional doubly porous PHEMA-based materials

Functional doubly porous polymeric materials based on cross-linked poly(2-hydroxyethyl methacrylate) (PHEMA) were engineered via novel porogen templating methodologies. Two straightforward and versatile strategies were implemented through the use of either CaCO₃ microparticles or poly(methyl methacrylate) beads as macroporogens, in conjunction with either hydroxyapatite nanoparticles of around 200 nm average diameter or a porogenic solvent (e.g., ethanol) as nanoporogens. Upon porogen removal, macropores with dimensions in the 100 μm range were generated, while the second porosity lied within the 1 μm order of magnitude, as evidenced by mercury intrusion porosimetry and scanning electron microscopy. The possibility to further functionalize such biporous PHEMA-based frameworks was investigated through a two-step synthetic approach involving an activation stage, followed by the coupling of propargylamine as a model compound. The success of the functionalization procedure was clearly demonstrated by Raman spectroscopy that indicated the occurrence of alkyne functionality within the biporous materials.     

Effect of Operating Parameters on the Dewatering Performance of Press Filters: A Sensitivity Analysis

To optimize the press filters commonly used to dewater residual sludge, the impact of the operating parameters must be better understood. The objectives of this article are (1) to identify the impact of the operating parameters on press filter performances and (2) to classify the operating parameters regarding their impact on dewatering performances. Experiments were performed with conditioned activated sludge in a tangential filtration cell, and a sensitivity analysis of the process was performed. This study emphasizes that cake thickness and filtration pressure have the most significant impacts on dewatering efficiency. These results suggest a promising outlook for press-filter optimization.     

Organic solvent nanofiltration with a Poly(dimethylsiloxane) membrane: Parameters affecting its sieving properties

In this study, retention experiments were performed to characterize the variable sieving properties of a poly(dimethylsiloxane) (PDMS) membrane in relation with operating parameters. The swelling, transmembrane pressure, and temperature are all known to impact the physicochemical properties and morphology of PDMS polymer and were therefore varied for the purposes of our retention experiments which assessed them with the homologous series of polyethylene glycols (PEGs; 200–1500 g mol^?1). The objectives were twofold—first, to evaluate the capacity to induce a targeted molecular weight cutoff (MWCO) by selecting appropriate filtration conditions and second to better understand the mechanisms involved during solvent‐resistant nanofiltration with PDMS. The selected solvents or solvent/solvent mixtures used throughout this study were found to induce swelling ratios of 1.16 (ethanol/ethyl acetate: 25/75), 1.26 (ethyl acetate), 1.33 (ethyl acetate/toluene: 50/50), and 1.41 (toluene), respectively. Linear correlations were obtained between the MWCO and the swelling ratio induced by each solvent and between the MWCO and the transmembrane pressure. Pore size calculations using solvent flux and retention data confirmed the variable sieving properties of the PDMS membrane in relation to the solvent‐induced swelling and applied transmembrane pressure. In addition, the study of the solute‐transfer rate through several operating conditions showed that both diffusive and convective transports occurred for the PEG solutes and that their respective contributions appeared dependent on the variable pore size of the PDMS membrane. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41171.     

Defect localization using voltage contrast IDDQ testing

I_DDQ testing detects a majority of faults occurring in logic,ICs. Nethertheless, it has not eliminated the complex task of fault isolation at the silicon level of ICs.Liquid Crystak or Emission Microscopy can deal with this challenge. Unfortunately these two techniques lack sensitivity for some defects when the abnormal current consumption (I_DDQ) remains weak.On the other hand we can use very powerful tools like the electron beam tester to deeply analyze faulty devices by internal contactless testing. In some laboratories, people have underlined the interest of merging the two techniques (I_DDQ testing and Voltage Contrast) to get fast and accurate defect localization. In this paper, we will move on to the next step of identifying practical key issues necessary for obtaining results on current VLSI.     

Enhanced optical trapping and arrangement of nano-objects in a plasmonic nanocavity

Gentle manipulation of micrometer-sized dielectric objects with optical forces has found many applications in both life and physical sciences. To further extend optical trapping toward the true nanometer scale, we present an original approach combining self-induced back action (SIBA) trapping with the latest advances in nanoscale plasmon engineering. The designed resonant trap, formed by a rectangular plasmonic nanopore, is successfully tested on 22 nm polystyrene beads, showing both single- and double-bead trapping events. The mechanism responsible for the higher stability of the double-bead trapping is discussed, in light of the statistical analysis of the experimental data and numerical calculations. Furthermore, we propose a figure of merit that we use to quantify the achieved trapping efficiency and compare it to prior optical nanotweezers. Our approach may open new routes toward ultra-accurate immobilization and arrangement of nanoscale objects, such as biomolecules.     

Transmission Electron Microscopy and UV–vis–IR Spectroscopy Analysis of the Diameter Sorting of Carbon Nanotubes by Gradient Density Ultracentrifugation

Diameter separation of single‐walled carbon nanotubes is achieved via the density gradient ultracentrifugation process. Statistical analysis of the separated samples is performed using high‐resolution transmission electron microscopy (HRTEM). The evolution of the diameter distribution with respect to the gradient density is extracted by analyzing hundreds of HRTEM images, and the results are found to be consistent with those estimated by UV–vis–IR spectroscopy. The efficiency of the separation process can be quantitatively characterized by the standard deviation of the diameter distribution, which is determined from the TEM analyses. This particular study indicated that for electric arc nanotubes dispersed in sodium cholate, diameter sorting is more efficient in the upper part of the gradient.