Digital embedded refractometer with temperature compensation

Temperature is one of the single most important factors influencing accurate refractometer readings and is one of the largest sources of error in measurement. A model based on neural networks, has been implemented to generate solution concentration data, knowing fluid temperature measurements in this solution. The neural network chosen in this study, is the hidden layer feed forward network. Its learning rule is based on the backpropagation of the error. Its training basis consists of concentration measurement, temperature data recorded every time. An in-line process measurement of refractive index (RI) works as a real-time predictive tool for the final concentration in process parameters is proposed. The acquired signal is transmitted, via the Bluetooth, to the processing and diagnostic unit. A predictive modelling using the neural networks enables us to predict its operation under various conditions within a temperature range from 0 up to 40 °C.     

Contrôle de topologie orienté stratégie basé sur des routeurs mobiles dédiés

Due to the inherent mobility within the ad hoc environment, network topology plays a key role on routing and network performance. In this paper we propose to control the ad hoc network morphology using a set of dedicated routers. The idea is to use positively the mobility, in order to enhance ad hoc network performance. Two deployment policies are studied for a global network connectivity or a limited network diameter. We describe the Mixed Integer Linear Programming (Milp) models for these deployment policies with respect to the constraints, and show the efficiency, of the described approach through simulations (NS-2).     

Comparison of the chemical composition of boron-doped diamond surfaces upon different oxidation processes

In spite of the high stability of polycrystalline diamond, oxidation of the hydrogenated surface is relatively easy to perform. This results in the introduction of ether (C–O–C), carbonyl (CO) and hydroxyl (C–OH) groups on the surface. For further surface functionalization, it is important to quantify the presence of each group on the diamond surface when different oxidation processes are used. In this paper, we investigate the composition of oxidized boron-doped diamond surfaces using X-ray photoelectron spectroscopy (XPS) when electrochemical, photochemical or oxygen plasma methods were employed to introduce oxygen functionalities on as-deposited diamond interfaces. Cyclic voltammetry and C–V measurements were additionally performed to identify more clearly the formation of C–OH, C–O–C and/or CO functions.     

Thiol-yne reaction on boron-doped diamond electrodes: application for the electrochemical detection of DNA-DNA hybridization events

Boron-doped diamond (BDD) interfaces were chemically functionalized through the catalyst free thiol-yne reaction. Different thiolated precursors (e.g., perfluorodecanethiol, 6-(ferrocenyl)-hexanethiol, DNA) were successfully "clicked" to alkynyl-terminated BDD by irradiating the interface at 365 nm for 30 min. Thiolated oligonucleotide strands were immobilized using the optimized reaction conditions, and the surface concentration was tuned to obtain a surface coverage of 3.1 × 10(12) molecules cm(-2). Electrochemical impedance spectroscopy (EIS) was employed to follow the kinetics of hybridization and dehybridization events. The sensitivity of the oligonucleotide modified BDD interface was assayed, and a detection limit of 1 nM was obtained.     

Biofilm and biomass characteristics in high-performance fluidized-bed biofilm reactors

Two laboratory-scale fluidized-bed biofilm reactors (FBBRs) were used to investigate the biomass concentration and the biofilm characteristics in a high-performance FBBR used for the denitrification of exceptionally high-nitrate wastewater (1000 mg N/L). Reported correlations by other workers for predicting the biomass concentration in FBBR were examined for their validity in comparison with the experimental results of this study and the best set of applicable correlations was recommended. The effects of the two main operational parameters, the superficial velocity and nitrogen loading rate on the biomass concentration in the FBBR were also studied. Correlations for the drag coefficient and the expansion index from the literature, together with the biofilm dry density correlation produced from this study were found to produce the best prediction of the FBBR biomass concentration compared to other reported correlations. The average biomass concentration in the FBBR decreased with the increase of the superficial velocity in the range of 45-65 m/h at all applied nitrogen loadings (i.e. 6, 8, 12 and 16 kg N/m3bedd).     

Adaptive leader follower control for multiple quadrotors via multiple surfaces control

Based on the multiple surface and fixed undirected communication topology, the adaptive leader follower control for multiple quadrotors is discussed. Our approach is based on leader follower architecture. Multiple surface control (MSC) is used to design consensus controller to make multiple quadrotors construct a formation during flying with the presence of uncertainty item caused by the ground effect during landing or taking off. Simulation results are presented to validate the effectiveness of the proposed controller.     

Droplet transport by electrowetting: lets get rough!

Since the pioneering works of Wenzel and Cassie Baxter in the 1930s, and now with the trivialization of the micro- and nanotechnology facilities, superhydrophobic surfaces have been announced as potentially amazing components for applications such as fluidic, optical, electronic, or thermal devices. In this paper, we show that using superhydrophobic surfaces in digital microfluidic devices could solve some usual limitations or enhance their performances. Thus, we investigate a specific monophasic (air environment) microfluidic device based on electrowetting integrating either a hydrophobic or a superhydrophobic surface as a counter-electrode. The droplet transport using a superhydrophobic surface compared with a classical hydrophobic system led to some original results. Characterization of the dynamic contact angle and the droplet shape allows us to get new insight of the fluid dynamics. Among the remarkable properties reported, a 30 % lower applied voltage, a 30 % higher average speed with a maximum instantaneous speed of 460 mm/s have been measured. Furthermore, we have noticed a huge droplet deformation leading to an increase by a factor 5 of the Weber number (from 1.4 to 7.0) on SH compared to hydrophobic surfaces. Finally, we discuss some of the repercussions of this behaviour especially for microfluidic device.     

Synthesis and characterization of poly(1-sila-cis-pent-3-enes) substituted with pendant pyridinyl groups

Poly[1-methyl-1-[3′-(3″-pyridinyl)propyl]-1-sila-cis-pent-3-ene], poly[1-phenyl-1-[3′-(3″-pyridinyl)propyl)-1-sila-cis-pent-3-ene], and poly[1-phenyl-1-(4′-pyridinyl)-1-sila-cis-pent-3-ene] were synthesized by the anionic ring-opening polymerization of 1-methyl-1-[3′-(3″-pyridinyl)propyl]-1-silacyclopent-3-ene, 1-phenyl-1-[3′-(3″-pyridinyl)propyl]-1-silacyclopent-3-ene, and 1-phenyl-1-(4′-pyridinyl)-1-silacyclopent-3-ene, respectively. These are the first polycarbosilanes which contain heterocyclic pyridine units as side-chain substituents. These polymers were characterized by¹H,¹³C, and²⁹Si NMR as well as by IR and UV spectroscopy. The molecular weight distributions were determined by gel permeation chromatography, glass transition temperatures, by differential seanning calorimetry: (DSC) and thermal behavior, by thermogravimetric analysis. (TGA).     

The role of impregnants in determining the behaviour of graphite anodes

The lifetime of graphite anodes in sulphuric acid media can be increased by a factor of 3.2 by multiple impregnation with coal tar pitch. For single impregnation, linseed oil yielded the largest improvement. The results were interpreted on the premise that properties such as viscosity, melting point and coking value determine the effectiveness of the impregnant. The proper selection of the impregnant and procedure of impregnation is dependent on the electrolysis temperature.     

Electrochemical investigation of the influence of thin SiOx films deposited on gold on charge transfer characteristics

The paper reports on the investigation of the electrochemical behavior of a thin gold film electrode coated with silicon dioxide (SiO_x) layers of increasing thickness. Stable thin films of amorphous silica (SiO_x) were deposited on glass slides coated with a 5 nm adhesion layer of titanium and 50 nm of gold, using plasma-enhanced chemical vapor deposition (PECVD) technique. Scanning electrochemical microscopy (SECM) and electrochemical impedance spectroscopy (EIS) were used to investigate the electrochemical behavior of the interfaces. In the case of SECM, the influence of the SiO_x thicknesses on the electron transfer kinetics of three redox mediators was investigated. Normalized current-distance curves (approach curves) were fitted to the theoretical model in order to find the effective heterogeneous first order rate constant (k_eff) at the sample. EIS was in addition used to confirm the diffusion barrier character of the SiO_x interlayer.