Integrated FDD system for valve stiction in a paperboard machine

The performance of a modern industrial plant can be severely affected by the performance of its key devices, such as valves. In particular, valve stiction can cause poor performance in control loops and can consequently lower the efficiency of the plant and the quality of the product. This paper presents an integrated FDD system for valve stiction which employs various FDD methods in a parallel configuration. A reliability index was integrated into each method in order to estimate their degree of influence in the final diagnosis of the system. Each method and the integrated system were tested using industrial data.     

Elastic Gallium Phosphide Nanowire Optical Waveguides—Versatile Subwavelength Platform for Integrated Photonics

Emerging technologies for integrated optical circuits demand novel approaches and materials. This includes a search for nanoscale waveguides that should satisfy criteria of high optical density, small cross-section, technological feasibility and structural perfection. All these criteria are met with self-assembled gallium phosphide (GaP) epitaxial nanowires. In this work, the effects of the nanowire geometry on their waveguiding properties are studied both experimentally and numerically. Cut-off wavelength dependence on the nanowire diameter is analyzed to demonstrate the pathways for fabrication of low-loss and subwavelength cross-section waveguides for visible and near-infrared (IR) ranges. Probing the waveguides with a supercontinuum laser unveils the filtering properties of the nanowires due to their resonant action. The nanowires exhibit perfect elasticity allowing fabrication of curved waveguides. It is demonstrated that for the nanowire diameters exceeding the cut-off value, the bending does not sufficiently reduce the field confinement promoting applicability of the approach for the development of nanoscale waveguides with a preassigned geometry. Optical X-coupler made of two GaP nanowires allowing for spectral separation of the signal is fabricated. The results of this work open new ways for the utilization of GaP nanowires as elements of advanced photonic logic circuits and nanoscale interferometers.     

Viral quantitative capillary electrophoresis for counting intact viruses

The quantification of a virus plays an important role in vaccine development, clinical diagnostics, and environmental contamination assays. In all these cases, it is essential to calculate the concentration or number of intact virus particles (ivp) and estimate the degree of degradation and contamination of virus samples. In this work, we propose a cost-efficient, robust method for the quantification and characterization of intact viruses based on capillary zone electrophoresis. This separation method is demonstrated on vaccinia virus (VV) with oncolytic properties. After virus sample preparation, the solution contains intact VV as well as broken viruses and residual DNA from the host cell used for preparation. Regulatory requirements limit the amount of the host cell DNA that can be present in vaccines or human therapeutics. We apply capillary electrophoresis to separate intact virus particles and the residual DNA and to measure the level of virus contamination with DNA impurities. Intercalating YOYO-1 dye is used to detect the encapsulated and free DNA by laser-induced fluorescence. After soft lysis of VV with proteinase K, all encapsulated DNA is dissolved to the free DNA. The change in peak areas and a DNA calibration curve help determine the initial concentration of intact viruses. This viral quantitative capillary electrophoresis (Viral qCE) is able to quantify the oncolytic vaccinia virus in the range of 10(6) to 10(12) ivp/mL.     

Millimeter-wave Ground-based Synthetic Aperture Radar Imaging for Foreign Object Debris Detection: Experimental Studies at Short Ranges

In this paper, millimeter-wave imaging of foreign object debris (FOD)-type objects on the ground is studied with the help of ground-based synthetic aperture radar (GB-SAR) technique. To test the feasibility of detecting runway FODs with this technique, some preliminary experiments are conducted within short antenna-to-target ranges of small imaging patches. An automated stripmap GB-SAR system with stepped-frequency transmission is constructed together with a quasi-monostatic data collection operation. The imaging experiments for various braces and screws are then carried out by using 32–36?GHz and 90–95?GHz frequency bands of the millimeter-wave. Images reconstructed by a matched-filter based algorithm are analyzed to determine the proper system parameters for an efficient imaging and to comprehend the factors against a successful detection. Results demonstrate the capability of GB-SAR imaging in accurately locating these FOD-like targets under near-range operating conditions.     

New Octopus-like Phthalocyanines as Fullerene Receptors: Synthesis and Photophysical Investigation

Octopus-like zinc and magnesium phthalocyaninates bearing eight flexible benzylated diethylene glycol chains were synthesized and their interaction with fullerenes C₆₀ and C₇₀ was investigated by UV-Vis spectrophotometric titration, as well as by steady-state and time-resolved fluorescence spectroscopy in chloroform and toluene media. These measurements revealed a high affinity of receptors for C₆₀ and C₇₀, with selectivity to C₇₀: binding constants for C₇₀ are almost two times higher than for C₆₀. These results are interpreted by means of quantum-chemical calculations using the PM6-DH2 Hamiltonian. The binding constants also depend on both the nature of the metal ion in the receptor and the solvent. It is expected that the obtained molecules and supramolecular complexes can be used for further elaboration of optoelectronic donor-acceptor materials.     

Limit Cycles in a Class of Hybrid Dynamical Systems

This paper deals with qualitative analysis of the so-called switched fluid networks. Such networks are used to model communication, computer, and flexible manufacturing systems. We prove that for any deterministic network from a specific class, there exists a finite number of limit cycles attracting all the trajectories of the system. Furthermore, we determine this number. Date received: March 11, 2000. Date revised: January 19, 2001.     

Self‐Assembly of Ferromagnetic Organic–Inorganic Perovskite‐Like Films

Perovskite‐based organic–inorganic hybrids hold great potential as active layers in electronics or optoelectronics or as components of biosensors. However, many of these applications require thin films grown with good control over structure and thickness—a major challenge that needs to be addressed. The work presented here is an effort towards this goal and concerns the layer‐by‐layer deposition at ambient conditions of ferromagnetic organic–inorganic hybrids consisting of alternating CuCl₄‐octahedra and organic layers. The Langmuir‐Blodgett technique used to assemble these structures provides intrinsic control over the molecular organization and film thickness down to the molecular level. Magnetic characterization reveals that the coercive field for these thin films is larger than that for solution‐grown layered bulk crystals. The strategy presented here suggests a promising cost effective route to facilitate the excellently controlled growth of sophisticated materials on a wide variety of substrates that have properties relevant for the high density storage media and spintronic devices.     

A model for cell-surface-exposed carbohydrate moieties suitable for structural studies by NMR spectroscopy

In the present study a synthetic glycolipid system is presented that can be readily incorporated into phospholipid micelles and that allows the study of cell-surface-exposed carbohydrate units by high-resolution NMR techniques. Here, we present an efficient route for the synthesis of glycolipid compounds that contain mannose, mannobiose, or mannotriose coupled either directly to an alkyl chain or through a poly(ethylene glycol) linker. Furthermore, we have validated our model system by measuring the binding of cyanovirin N (CV-N), a cyanobacterial protein that binds with nanomolar affinity to the terminal arms of high-mannose structures of the HIV surface-envelope glycoprotein gp120, to glycolipids the carbohydrate portions of which comprise the corresponding high-mannose moieties. From the results of chemical-shift mapping with uniformly (15)N-labelled CV-N, we conclude that binding to the protein occurs at sites similar to those involved in binding the nonconjugated carbohydrates. We characterized the insertion of the glycolipids into dodecylphosphocholine (DPC) micelles by measuring translational diffusion, and we observed that the diffusion constants of the glycolipids were very similar to those of the DPC micelles themselves, but significantly deviated from those of the free glycolipids. We also present experimental proof that the glycolipids remain inserted in the micelles while binding to CV-N. Finally, by addition of a ligand that had a higher affinity to CV-N but which was not attached did not couple to a lipid anchor, CV-N could be released from the glycolipid and, hence, from the micelle-associated state.     

31P MAS NMR Spectroscopy of Hexachlorocyclotriphosphazene at Different Stages During Thermal Ring-Opening Polymerization

The basic concepts of solid-state nuclear magnetic resonance (NMR) spectroscopy are explained in a clear and concise manner. First the reader is introduced to the principles of NMR spectroscopy and techniques that are most commonly utilized today. Next, an overview of advanced magic-angle spinning (MAS) NMR experiments, which can provide valuable insight into molecular structure, connectivity, dynamics, domains, and phases of inorganic polymers, is presented. The final chapter discusses the major classes of inorganic polymers, their properties and applications. It addresses their characterization including, if any, the role of solution and solid-state NMR spectroscopy, and provides prospective on potential applications of these techniques for the given class of material.     

Grafting of titanium dioxide microspheres with a temperature‐responsive polymer via surface‐initiated atom transfer radical polymerization without the use of silane coupling agents

Titania microspheres with narrow size distribution and diameters of about 1 µm were prepared and subsequently functionalized using surface‐initiated atom transfer radical polymerization (ATRP) of N‐isopropylacrylamide. The ATRP initiator was immobilized on the particle surface via acylation of surface hydroxyl groups with α‐bromoisobutyryl bromide. Subsequently, an established ATRP reaction system was used for the preparation of titania surface‐grafted poly(N‐isopropylacrylamide) (PNiPAAm). Characterization was performed with electron microscopies, X‐ray diffraction, infrared spectroscopy and dynamic light scattering. It was found that the particle size in aqueous dispersions changed reversibly with temperature as expected for a shell of PNiPAAm, a polymer with a lower critical solution temperature at 32 °C. This confirmed the successful preparation of functional, stimuli‐responsive TiO₂ microparticles via a straightforward controlled surface‐initiated polymerization method.