A facile route to the new triazene dyes based on substituted pyrazolidin-3,5-dione derivatives

Several substituted triazenes dyes were synthesized by coupling functionalized pyrazolidin-3,5-dione derivatives, to various heteroarene azides in excellent yields (98%). Electron delocalization between the two coupled components of these triazene dyes was studied using UV-vis spectra and NMR spectroscopy. Their thermolysis was investigated and by using an isotopically labeled triazene, the mechanism decomposition reaction was also identified. The protolysis of these triazenes was evaluated and showed that they are highly stable and even in strongly acidic medium.     

Modification of local asphalt with epoxy resin to be used in pavement

The durability of asphalt pavement is greatly influenced by the environmental changes during the year. In this paper, we prepared asphalt modified by mixing asphalt 60/70 with epoxidized natural rubber (ENR) in different percentages (5, 10 and 15%), which was achieved using preformed peracetic acid (aqueous solution 59%) at 60–80 °C, then molten cross-linker maleic anhydride (MA) was added to modified asphalt until homogenous blends are achieved. Marshall test was used to evaluate the asphalt pavement performance depending on the curing time and hardener concentration. To measure marshall test, the pervious mixture was stirred with aggregate jop formula mix (JMF) and 40% MA at 150–170 °C for 20 h and 1600 rpm. From the obtained data, it was found that asphalt mixed with 15% of ENR + 40% MA achieves a high stability (16,632 Newton), air voids of 2.5%, flow of 2.9 mm and mineral voids of 14.6%. While, the stability of the unmodified asphalt was (11,500 Newton), the flow 3.2 mm, the suitable air void value was 3.7% at 5.5% with the same conditions.     

Investigation of iodine bioavailability from chicken eggs versus iodized kitchen salt with in vitro method

The goal of the presented studies was to investigate speciation and bioavailability of iodine from chicken eggs versus iodized kitchen salt with an in vitro method. Determination of iodine total content in chicken eggs and iodized kitchen salt was carried out by inductively coupled plasma mass spectrometry (ICP MS). The majority of iodine was accumulated in the yolk—the concentration was even 37 times higher than in white. Chicken eggs were treated with buffer (Tris HCl pH = 7.5) and enzymatic extraction media and analyzed by size exclusion chromatography hyphenated with inductively coupled plasma mass spectrometry (SEC ICP MS). The enzymatic extraction being an in vitro bioavailability assessment method was based on two-stage digestion model simulating gastric (pepsin digestion) and intestinal (pancreatin digestion) juices. Speciation analyses along with bioavailability studies presented iodide as the major form in chicken eggs. The bioavailability was established as 33% from white and 10% from yolk and decreased with longer time of boiling. It allows to suggest that the majority of iodine remains in forms bound to non-digestible coagulated and water-insoluble proteins.     

<Emphasis Type="Italic">In Situ</Emphasis> Spectral Reflectance Investigation of InAs/GaAs Heterostructures Grown by MOVPE

Metalorganic vapor-phase epitaxy of InAs/GaAs heterostructures was monitored in situ by spectral reflectance in the wavelength range from 600 nm to 1000 nm. Three-dimensional (3D) plots of reflectivity as a function of time and wavelength were used to determine the growth rate evolution. Theoretical simulation of reflectivity signals was carried out by combining a transfer matrix method and a multi-sublayer model. In spite of fixed growth parameters, there was temporal variation of the growth rate. By adjusting simulated reflectivity curves, optical constants of the InAs layer at 450°C were determined. The E ₁ critical point energy was also found experimentally at this temperature. Good agreement with calculated values is obtained.     

Improvement of Power Supply Rejection Ratio in Wheatstone-bridge based piezoresistive MEMS

This paper deals with the design of MEMS-based sensors with piezoresistive transduction. It is demonstrated that when the sensor topology does not allow a perfect matching of resistances in the conditioning circuit (typically a Wheatstone bridge), the resolution of the system is limited by the ability to reject power supply noise. As this ability increases when the output offset of the bridge decreases, the proposed architecture implements a feedback loop to control MOS transistors inserted in the Wheatstone bridge to compensate resistor mismatches. This zero-offset bridge exhibits a very good offset cancellation and therefore a better resolution.     

Analysis,modeling, identification and control of pancake DC torque motors: Application to automobile air path actuators

This article is focused on the working, modeling and control of pancake DC torque motors, used in automobile engine air path actuators. These motors, with a limited working angle, provide high torque which makes them suitable for use in actuators without any additional gear reduction. The torque is a nonlinear function of the motor angle. This article provides a modeling scheme, suitable for control purposes, which takes into consideration nonlinearities arising from friction and operating temperature. Comparison between simulation and experiments shows the effectiveness of the proposed model. Second order sliding mode control has been applied to the actuators for robust control under the influence of nonlinearities and uncertainties. The effectiveness of the control algorithm has been proven experimentally.     

Identification and characterization of a chitinase of Stenotrophomonas maltophilia, a bacterium that is antagonistic towards fungal phytopathogens

A rhizosphere strain of Stenotrophomonas maltophilia strain MUJ that is strongly antagonistic towards fungal phytopathogens secretes to the culture medium a single form of active chitinolytic enzyme belonging to family 18 of glycosyl hydrolases. The chitinase was purified by a two-stage procedure embracing fractionation with ammonium sulfate and affinity chromatography. The molecular mass of the purified enzyme determined by SDS-PAGE was approximately 52 kDa. The enzyme demonstrated highest activity at 45°C and pH 6.8. The enzymatic protein showed considerable thermal stability during 2 h incubation at 45°C. The activity of the enzyme was strongly inhibited in the presence of Hg²⁺ and Cu²⁺. By applying mass spectrometry analysis, the peptides derived from the purified chitinase were assigned to amino acid sequences of the type ChiA chitinases synthesized by Stenotrophomonas bacteria. The purified enzyme inhibited the growth of fungal phytopathogens belonging to the genera Fusarium, Rhizoctonia and Alternaria.     

Partial differential equation-based approach for empirical mode decomposition: application on image analysis

The major problem with the empirical mode decomposition (EMD) algorithm is its lack of a theoretical framework. So, it is difficult to characterize and evaluate this approach. In this paper, we propose, in the 2-D case, the use of an alternative implementation to the algorithmic definition of the so-called "sifting process" used in the original Huang's EMD method. This approach, especially based on partial differential equations (PDEs), was presented by Niang in previous works, in 2005 and 2007, and relies on a nonlinear diffusion-based filtering process to solve the mean envelope estimation problem. In the 1-D case, the efficiency of the PDE-based method, compared to the original EMD algorithmic version, was also illustrated in a recent paper. Recently, several 2-D extensions of the EMD method have been proposed. Despite some effort, 2-D versions for EMD appear poorly performing and are very time consuming. So in this paper, an extension to the 2-D space of the PDE-based approach is extensively described. This approach has been applied in cases of both signal and image decomposition. The obtained results confirm the usefulness of the new PDE-based sifting process for the decomposition of various kinds of data. Some results have been provided in the case of image decomposition. The effectiveness of the approach encourages its use in a number of signal and image applications such as denoising, detrending, or texture analysis.     

Progressive collapse of 2D reinforced concrete structures under sudden column removal

Once a column in building is removed due to gas explosion, vehicle impact, terrorist attack, earthquake or any natural disaster, the loading supported by removed column transfers to neighboring structural elements. If these elements are unable to resist the supplementary loading, they continue to fail, which leads to progressive collapse of building. In this paper, an efficient strategy to model and simulate the progressive collapse of multi-story reinforced concrete structure under sudden column removal is presented. The strategy is subdivided into several connected steps including failure mechanism creation, MBS dynamic analysis and dynamic contact simulation, the latter is solved by using conserving/decaying scheme to handle the stiff nonlinear dynamic equations. The effect of gravity loads, structure-ground contact, and structure-structure contact are accounted for as well. The main novelty in this study consists in the introduction of failure function, and the proper manner to control the mechanism creation of a frame until its total failure. Moreover, this contribution pertains to a very thorough investigation of progressive collapse of the structure under sudden column removal. The proposed methodology is applied to a six-story frame, and many different progressive collapse scenarios are investigated. The results illustrate the efficiency of the proposed strategy.