An Efficient Web Page Change Detection System Based on an Optimized Hungarian Algorithm

This paper describes an efficient Web page change detection system based on three optimizations that were implemented on top of the Hungarian algorithm, which we employ to compare trees that correspond to HTML Web pages. The optimizations attempt to stop the comparator algorithm that employs this O(n³) algorithm before it completes all its iterations based on criteria having to do with properties of HTML and heuristics. Analysis and experimental results prove the effectiveness of these optimizations and their ability to render O(n²) performance, where n denotes the number of nodes in the tree. A complete system was implemented and used to carry out the performance experiments. This system includes functionalities and interfaces for processing user requests, fetching Web pages from the Internet, allowing users to select zones in Web pages to monitor, and highlighting changes on the Web pages being monitored     

Concentration jump experiments for the precise determination of rate constants of reverse reactions in the millisecond time range

Low dissociation or reverse rate constants of single-step or multistep complex formation equilibria are usually obtained with reduced precision from standard stopped-flow binding experiments by determination of the intercept of the concentration dependence of k(obs). Large and fast concentration jumps, based on two different step-motor-driven mixing setups, are performed with 60-300-fold dilutions that allow the precise, convenient, and independent determination of dissociation rate constants in the range of approximately 0.1-100 s(-1) in a single stopped-flow dissociation experiment. A theoretical basis is developed for the design and for the evaluation of such dilution experiments by considering the rebinding occurring during dissociation. The kinetics of three chemical systems are investigated, the binding of Mg2+ to 8-hydroxyquinoline as well as of Ca2+ and K+ to the cryptand [2.2.2], by carrying out standard stopped-flow binding as well as dissociation experiments employing various dilution factors. The advantage of the dilution method for investigating chemical and biological systems is emphasized.     

Assessment of frictional resistance and surface roughness in orthodontic wires coated with two different nanoparticles

Several mechanical and biological factors may change the orthodontic wire frictional resistance (FR). Titanium dioxide (TiO₂) and silica dioxide (SiO₂) nanoparticle (NP) coatings may be used to improve the characteristics of materials, reducing FR between archwire and bracket. This in vitro study aimed to evaluate the FR of orthodontic wires with and without coating in both dry and wet environments and measure the surface roughness (SR). One hundred and eighty segments of rectangular Cr–Ni orthodontic wires (Morelli Co, Brazil) were divided into three groups according to the NP coating applied: TiO₂ group; SiO₂ group; and control group. The SR parameters were measured in an optical profilometer, the surface morphology was analyzed with scanning electron microscopy (SEM), and FR was performed in a universal testing machine in dry and wet environments (n = 30). The statistical analysis was performed using the Generalized Estimated Equations model with a Bonferroni post-test (α = 0.05). It was observed that SiO₂ NP coating decreased FR significantly when compared to the TiO₂ and control groups, in both environments (p < .001). The SiO₂ and TiO₂ groups presented statistically lower SR than the control group and were similar to each other (p < .001). The SiO₂ group presented the lower depth of Valley parameter than the TiO₂ group (p < .001). The SEM showed that the TiO₂ coating had the most heterogeneous surface morphology than the SiO₂ and control groups. The orthodontic wires with NP coating modified the FR and morphology. The SiO₂ coating reduced FR in both dry and wet environments and decreased SR.

• Titanium dioxide (TiO₂) and silica dioxide (SiO₂) nanoparticles coatings may be used to reduce frictional resistance (FR) between archwire and bracket as well as to improve surface morphology.
• The SiO₂ coating reduced FR in both dry and wet environments and decreased the SR of Cr–Ni orthodontic wire.
• The TiO₂ coating promoted the most heterogeneous surface morphology of Cr–Ni orthodontic wire.

     

Use of the smart technology for water quality control: feedback from large-scale experimentation

The main purpose of drinking water network is to ensure safe quality of water to users. However, accidental contamination and malicious attacks in water networks can degrade the water quality. Such critical events threat the human health and lead to harmful diseases. Water utilities are concerned by the control of water quality. Since conventional methods based on laboratory analyses require several days, online control technology presents good opportunity to rapid detection of any water contamination. Devices based on smart technology have been developed for real-time control of the water quality. However, the use of these devices is recent and yet requires investigations. This paper presents feedback of the use of the smart technology in a large-scale experimentation conducted at the campus of Lille University within the European project “SmartWater4Europe”. Two devices are used: S::CAN, which measures various parameters such as Conductivity and Turbidity and EventLab, which measures the variation of the refractive index. This paper presents the implementation of these devices, data storage and management as well as analysis of recorded data.     

Smart water technology for leakage detection: feedback of large-scale experimentation

Recent advances in intelligent water meter technology have improved the quantitative monitoring in water supply and distribution systems. Smart meters using automated meter reading (AMR) technology allow water utilities to: (a) provide clear consumption patterns which can help customers to track and control their water usage and (b) improve active leakage targeting and leak detection capability. This paper presents a feedback about the use of AMR system to detect leakage in a large-scale experimentation, which is conducted at the Scientific Campus of the University of Lille, which stands for a small town of 25,000 users. This paper presents the demonstration site as well as its monitoring using AMR technology and how this technology allowed a rapid detection of water leakage.     

Importance of Time-Dependent Wetting Behavior of Gas-Diffusion Electrodes for Reactivity Determination

Tin foil and SnO_x/C gas-diffusions electrodes (GDEs) were investigated via electrochemical impedance spectroscopy (EIS) to extract the differential double-layer capacitance (C_dl) as a measure of the wetted surface area. Time-dependent C_dl values revealed an immediate stationary wetting for tin foil electrodes while a distinct increase of C_dl – which becomes stationary with time – was observed for GDEs. The time-dependent wetting behavior of the GDEs was substantiated by physical post-mortem characterization. Since the wetted surface area determines the number of reachable active sites the performance of GDEs should be normalized to the wetted surface area for evaluation of reactivity.     

Color modeling of stratified pictorial layers using the radiative transfer equation solved by the auxiliary function method

The diffuse reflectance spectra and the trichromatic coordinates of diffusing stratified paints are modeled. Each layer contains its own pigments, and their optical properties are first determined from experiments. The radiative transfer equation is then solved by the auxiliary function method for modeling the total light scattered by the stratified systems. The results are in good agreement with experimental spectra and validate the modeling. The calculations are then applied on the same stratified systems to study the influence of the observation angle in a bidirectional configuration and to study the influence of the thickness of the layers in a given configuration. In both cases, the reflectance spectra and the trichromatic coordinates are calculated and compared.     

Three-dimensional morphology of GaP-GaAs nanowires revealed by transmission electron microscopy tomography

We have investigated the morphology of heterostructured GaP-GaAs nanowires grown by metal-organic vapor-phase epitaxy as a function of growth temperature and V/III precursor ratio. The study of heterostructured nanowires with transmission electron microscopy tomography allowed the three-dimensional morphology to be resolved, and discrimination between the effect of axial (core) and radial (shell) growth on the morphology. A temperature- and precursor-dependent structure diagram for the GaP nanowire core morphology and the evolution of the different types of side facets during GaAs and GaP shell growth were constituted.     

Dye-sensitized solar cells based on nanocrystalline titania electrodes made at various sintering temperatures

Dye-sensitized solar cells were made by using nanocrystalline titania deposited on Fluorine-doped SnO2 (FTO) electrodes. Nanocrystalline titania deposition was made by the sol-gel method using reverse micelles of bis(2-ethylhexyl) sulfosuccinate sodium salt (AOT) in cyclohexane as reaction medium. This surfactant could be easily removed from the deposited nanocomposite organic-inorganic film by simple rinsing with distilled water, without affecting titania adherence on FTO electrode. These nanocrystalline titania electrodes were used to make solar cells either without sintering or after sintering at various temperatures. Sintering extensively affected short circuit current but had small effect on device open-circuit voltage. Thus satisfactory photovoltaic response could be obtained even with devices made of non-sintered (room-temperature) titania.     

ZnO Nanowires,Nanotubes, and Complex Hierarchical Structures Obtained by Electrochemical Deposition

Increasing the aspect ratio of ZnO nanostructures is one possible strategy to improve their thermoelectric properties. ZnO nanostructures with one-dimensional (1D) and three-dimensional (3D) morphologies were obtained using electrochemical deposition. Adjusting various deposition parameters made it possible to obtain arrays of vertically aligned ZnO nanowires (NWs) with controlled dimensions, density, and electrical properties. The concentrations of zinc or chloride ions in the solution were found to be key parameters. ZnO NWs were transformed into ZnO nanotubes (NTs), with an increased aspect ratio compared with the NWs, by selectively dissolving the core of the ZnO NWs in a concentrated KCl solution. The aspect ratio was strongly increased when the ZnO NWs were hierarchically organized in a 3D morphology. The synthesis of thin films composed of ordered hollow urchin-like ZnO NW structures was performed by combining the electrochemical deposition and polystyrene sphere templating methods. The electronic properties of the urchin-like ZnO structures were investigated by means of photoluminescence and transmission measurements.