Hydrothermal synthesis,characterization and photodegradation of organic pollutants of CoCr2O4/Ag nanostructure and thermal stability of epoxy acrylate nanocomposite

Present work describes a facile method to prepare CoCr₂O₄ nanostructured using of Co(acac)₂·4H₂O and CrCl₃·6H₂O as cobalt and chrome sources respectively. 2-Hydroxy-1-naphthaldehyde-1,4-diaminobutane and CTAB was applied as stabilization agents. N(Et)₃, NaOH and tetraethylenepantamine (TEPA) were used as alkaline agent. TEPA and 2-hydroxy-1-naphthaldehyde-1,4-diaminobutane were chosen as the best alkaline agent and stabilization agent respectively. Silver nanoparticles were doped to the product by using photodeposition approach. The structural, optical, and morphological characteristics of as-synthesized CoCr₂O₄ and CoCr₂O₄/Ag nanostructures were analyzed using EDS, SEM, VSM, XRD, FT-IR and DRS spectroscopy. The photocatalytic behavior of CoCr₂O₄ nanoparticles was evaluated using the degradation of various organic pollutants (Rhodamine B, methylene blue and methyl orange) under UV irradiation. Also the effect of reaction parameters such as pH, on the grain size and shape of the nanoparticles were investigated. The influence of the CoCr₂O₄/Ag NPs on the thermal properties of epoxy acrylate was investigated by using thermogravimetry analysis. Results indicate that, CoCr₂O₄/Ag nanoparticles can enhance the thermal stability of the epoxy acrylate matrix.     

Online streaming feature selection: a minimum redundancy,maximum significance approach

Pattern Analysis and Applications - All the traditional feature selection methods assume that the entire input feature set is available from the beginning. However, online streaming features (OSF)...     

Unraveling the effect of dislocations and deformation-induced boundaries on environmental hydrogen embrittlement behavior of a cold-rolled Al–Zn–Mg–Cu alloy

The effect of dislocation substructure, and deformation-induced boundaries on the hydrogen embrittlement (HE) behavior and the fracture mechanism of a 7xxx series aluminum alloy was investigated using X-ray diffraction line-profile analysis, electron backscatter diffraction, transmission electron microscopy, thermal desorption spectroscopy, and visualization of hydrogen. Hydrogen resides at interstitial lattice sites, statistically-stored dislocations (SSDs), and high-angle boundaries (HABs). SSDs are not the main trap site affecting HE behavior of the alloy. However, the HABs with the high desorption energy act as an almost irreversible trap site, which strongly absorbs hydrogen. It was firstly reported that the higher density of HABs as a strong trap site in a deformed 7xxx series aluminum alloy leads to decreasing the possibility of building up a critical hydrogen concentration required for crack initiation in a typical HAB, resulting in an excellent hydrogen embrittlement resistance.     

Optimal design of methane tri-reforming reactor to produce proper syngas for Fischer-Tropsch and methanol synthesis processes: A comparative analysis between different side-feeding strategies

Assessment of the recent research on the side-feeding strategy in the methane tri-reforming reactor, suggests that this procedure can be a beneficial method for producing syngas. In the present study, special attention is given to the length of methane tri-reformer due to its significant effect on the residence time of distributed components, reaction pathways, synthesis gas production, and reactor performance in side-feeding procedures. The optimal design of three types of membrane tri-reforming reactor, containing O-MTR, H-MTR, and C-MTR, in which O₂, H₂O, and CO₂ permeate as the distributed reactants through the micro-porous membrane, respectively, as well as the conventional tri-reformer (MTR) was carried out to produce proper syngas for methanol and gas-to-liquid (GTL) units. The results show that the O-MTR offers the most advantages in terms of CH₄ conversion (i.e., 99.98%), H₂ yield (i.e., 1.91), and catalyst lifetime due to no formation of hot spot temperature. Additionally, the CH₄ conversion and H₂ yield in the O-MTR increased by 5% compared to the MTR. However, the length of these reactor structures to produce appropriate syngas for Fischer-Tropsch and methanol synthesis processes was in the following order: MTR < C-MTR $?$ O-MTR < H-MTR.     

Studies of thermal,mechanical properties,and kinetic cure reaction of carboxyl-terminated polybutadiene acrylonitrile liquid rubber with diepoxy octane

Epoxy resins, despite their unique properties, have limitations in many applications due to their low fracture toughness. One of the most effective methods to overcome this limitation is to use toughening agents, such as carboxyl terminated poly butadiene-acrylonitrile (CTBN) in the epoxy matrix. CTBN can react with various compounds, such as epoxies. In this study, we investigated the severity of CTBN sedimentation with di epoxy octane (DEO) in the presence basis catalysts. The studied of the physical properties of the synthesized copolymer in the presence of pyridine compared to other catalysts increases mechanical properties (248.43% elongation, 0.63 MPa strength, and 32 hardness with Shore A) and decreases the glass transition temperature (−45.1) of the copolymer. Investigated the cure kinetics of the CTBN-DEO reaction was in the presence of pyridine using a nonisothermal technique of differential scanning calorimetry, and the curing kinetic parameters, such as activation energy (E_a), pre-exponential factor (A), and rate constant (k), were calculated by different kinetic methods. The obtained curing kinetic values with different kinetic methods are well-matched, the E_a values are in the range of 91.3–97.1 kJ.mol⁻¹ and the A values are in the range of 0.48 × 10¹¹–1.51 × 10¹¹ S⁻¹.     

Use of hyperspectral imaging for evaluation of the shelf-life of fresh white button mushrooms (Agaricus bisporus) stored in different packaging films

The shelf life of mushrooms packaged using different polymer top-films (PVC, PET with different levels of perforations) was investigated using hyperspectral imaging (HSI). Packaged mushrooms were stored at 4 ± 0.2 °C for 14 days and weight loss, Hunter L, a, b values, maturity index and in-pack gas composition (% CO₂ and O₂) were also measured. The results obtained showed that the PET film perforated with small holes (1 mm in diameter) was generally superior in terms of maintaining overall mushroom quality. Regression models were built to correlate HSI data with measured quality parameters. Prediction maps were generated from hyperspectral data to show the model performance at pixel level. Results presented in this work show hyperspectral imaging can be used to evaluate the effect of different packaging systems on mushroom quality and that perforated PET packaging film is a viable alternative to the conventional PVC packaging, facilitating an increase in shelf life from 10 to 14 days.Industrial relevanceThe present study demonstrates HSI can be used for rapid evaluation of mushroom quality facilitating non-destructive evaluation of the effect of packaging systems on mushroom shelf-life. In addition, this work suggests an effective packaging solution to extend shelf life of mushrooms during storage. The proposed solution potentially improves the packaging recyclability as the same polymer material (PET) is used for the tray and top film, compared to conventional mushroom packaging where PVC is used for the top film and polypropylene (PP) for the tray.     

Conductometric simultaneous determination of acetic acid, monochloroacetic acid and trichloroacetic acid using orthogonal signal correction-partial least squares

A simultaneous conductometric titration method for determination of mixtures of acetic acid, monochloroacetic acid and trichloroacetic acid based on the multivariate calibration partial least squares is proposed. It is possible to obtain an adjustable model to relate squared concentration values of the mixtures used in the calibration range by conductance. The effect of orthogonal signal correction (OSC) as a preprocessing technique used to remove the information unrelated to the target variables is studied. The calibration model was build using conductometric titrations data of 16 mixtures of three acids. The concentration matrix was designed by a orthogonal design. The root mean squares error of prediction (RMSEP) for acetic acid, monochloroacetic acid and trichloroacetic acid with and without OSC were 0.08, 0.30 and 0.08, and 0.15, 0.40 and 0.18, respectively. The results obtained by OSC-PLS are better than the PLS and this indicate the successful application of the OSC filter as a good preprocessing method in multivariate calibration methods. The proposed procedure allows the simultaneous determination of these acids, in the synthetic mixtures.     

A qualitative X-ray analysis of white and grey mineral trioxide aggregate using compositional imaging

Mineral trioxide aggregate (MTA) is used in endodontics as a filling and sealant material. An earlier commercial formulation Grey MTA (GMTA) was liable to became progressively discoloured, and a whiter version (WMTA) has been introduced for cosmetic reasons. This study compares the composition and particle size distribution of the two formulations using energy dispersive X-ray analysis in a scanning electron microscope. Particle size is smaller in WMTA. X-ray analysis reveals similar major peaks (calcium, silicon and bismuth) but those of the minor elements aluminium, magnesium and particularly iron are considerably less in WMTA, which may account for the colour difference. Neither contains phosphorus, a major constituent of the original formulation. Author to whom all correspondence should be addressed