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21.
Synthesis of a novolac‐based 3‐aminopropylsiloxane resin and its application for the removal of Cu2+, Cr3+, and Ni2+ from electroplating wastewater
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Khaled Abou‐El‐Sherbini Mohamed A. Nour Abd‐El‐Ghany Soliman Saad S. Elmorsy 《应用聚合物科学杂志》2014,131(21)
Novolac resin was modified with 3‐aminopropyltrimthoxysilane to obtain phenol‐formaldehyde‐aminopropylsiloxane resin (PF‐APS). Fourier transformation infra‐red spectra, thermogravimetric analysis, elemental analysis, and pH‐metric titration were used to characterize PF‐APS. Its chemical formula was suggested to be C14H12.49N0.1O2Si0.1. The resin shows high experimental metal ions uptake capacity within short time of equilibration. The metal capacity was determined by atomic absorption spectrometry to be 0.787 mEq Cu/g. Maximum separation efficiencies of Cu2+, Cr3+, and Ni2+ from aqueous solutions on PF‐APS were at pH 8.0 and time of stirring 60 min; 94.0%, 90.8%, 83.2%, respectively. No significant interference from the background ions Na+, Cl?, and was observed on the separation process. The heavy metal ions were eluted using 0.01 mol L?1 EDTA at 65°C releasing >94% of the separated metal ions. The method of separation was applied successfully to remove the heavy metal ions Cu2+, Cr3+, and Ni2+ from electroplating wastewater from Dekirnis, Dakahlia Governorate, Egypt. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40993. 相似文献
22.
The initial fretting damage in a glass/PMMA contact was investigated by means of experiments and numerical (F.E.M.) simulations. Both micro-crack nucleation at the contact edges and particle detachment were identified on the PMMA's surface. Micro-crack initiation was related to the combination of high tensile stresses and positive hydrostatic pressures which are known to enhance crazing. During the early stages of the fretting tests, the distribution of the detached particles within the contact was correlated to the spatial distribution of the cumulative interfacial energy dissipated by friction. As the number of cycles was increased, it was observed that detached particles moved toward the middle of the contact. On the basis of FEM simulations, this particle displacement within the contact was attributed to the existence of differential micro-displacements during the fretting cycle. 相似文献
23.
The effects of growth temperature and salinity on the cellular fatty acids were investigated on Aeromonas caviae, Aeromonas hydrophila and Aeromonas sobria. Under optimal growth conditions, fatty acids patterns were dominated by even-numbered chains C(16:0), C(16:1cis9), C(18:1cis11), C(12:0) and C(14:0). Growth temperature modifications induced, in the three Aeromonas species, important changes in fatty acid (i) unsaturation, (ii) branching and (iii) chain length. An important decrease in the C(18:1cis11) fatty acid content was observed for the three species below 15 degrees C and above 25 degrees C. The evolution of C(18:1cis11) and C(16:0) showed a mirror image for the three Aeromonas species. Low NaCl concentrations did not elicit significant changes in the fatty acids content of the three Aeromonas species. However, for high NaCl concentration in the medium, the growth ability was related to an important decrease of the unsaturated to saturated fatty acids ratio indicating a membrane rigidification. Thermal and salinity adaptations were branched fatty acid-dependent for A. caviae, whereas this phenomenon was less significant for A. hydrophila and A. sobria. 相似文献
24.
Tabti Sabrina Benchettara Abdelkader Smaili Fatiha Benchettara Abdelhakim Berrabah Salah Eddine 《Journal of Applied Electrochemistry》2022,52(8):1207-1217
Journal of Applied Electrochemistry - The modification of an iron electrode was carried out according to the following two steps. In a first step, a cathodic reduction is performed to form a film... 相似文献
25.
Abdelkader Kahouli Olivier Gallot‐Lavallée Pacal Rain Olivier Lesaint Christophe Guillermin Jean‐Marc Lupin 《应用聚合物科学杂志》2015,132(28)
The dielectric properties of two grades of bi‐oriented isotactic polypropylene were studied with a variety of techniques: breakdown field measurements, dielectric spectroscopy, thermally stimulated depolarization currents (Is), and direct‐current (dc) conduction I values. Standard polypropylene (STPP) and high‐crystallinity polypropylene (HCPP) films were investigated. Measurements were carried out over a wide temperature range (?150°C/+125°C). The breakdown fields in both materials showed a very small difference. On the other hand, the dielectric losses and dc conduction I values were significantly lower in HCPP. Both materials showed a decrease in the dielectric loss versus temperature in the range 20–90°C; this is favorable for application in alternating‐current power capacitors. The analysis of the dc I value allowed us to find evidence of two main conduction mechanisms: (1) below 80°C in both materials, a hopping mechanism due to the motion of electrons occurred in the amorphous phase, and (2) above 80°C, ionic conduction occurred in HCPP, and hopping conduction occurred in STPP. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42224. 相似文献
26.
Asmaa Argoub Rachid Ghezini Cherifa Bachir Bouhadjar Boukoussa Amine Khelifa Abdelkader Bengueddach Peter G. Weidler Rachida Hamacha 《Journal of Porous Materials》2018,25(1):199-205
MIL-101@g-C3N4 nanocomposite was prepared by solvothermal synthesis and used for CO2 adsorption. The parent materials (MIL-101 and g-C3N4) and the MIL-101@g-C3N4 were characterized by X-ray diffraction, argon adsorption/desorption, Fourier transform infrared spectroscopy, thermal analysis (TG/DTA), transmission electronic microscopy, and Energy-dispersive X-ray spectroscopy. The results confirmed the formation of well-defined MIL-101@g-C3N4 with interesting surface area and pore volume. Furthermore, both MIL-101 and MIL-101@g-C3N4 were accomplished in carbon dioxide capture at different temperatures (280, 288, 273 and 298 K) at lower pressure. The adsorption isotherms show that the nanocomposite has a good CO2 adsorption affinity compared to MIL-101. The best adsorption capacity is about 1.6 mmol g?1 obtained for the nanocomposite material which is two times higher than that of MIL-101, indicating strong interactions between CO2 and MIL-101@g-C3N4. This difference in efficacy is mainly due to the presence of the amine groups dispersed in the nanocomposite. Finally, we have developed a simple route for the preparation of an effective and new adsorbent for the removal of CO2, which can be used as an excellent candidate for gas storage, catalysis, and adsorption. 相似文献
27.
Abdelkader Tizaoui 《Journal of Fusion Energy》2009,28(4):342-345
In this note, we propose an iterative methods technique for solving the neutron transport equation in 1-D spherical geometry.
More precisely we analyze the theoretical and numerical aspect of Jacobi and Gauss-Siedel algorithms in an infinite dimension,
and compare there with the classical method. These algorithms are based on a splitting of the collision operator taking into
account the characteristics of the transport operator. One of the advantages of these algorithms is that give a good rate
of convergence, and they are independent of the discretization chosen for the neutron transport equation. 相似文献
28.
Abdelkader Nour Samir Lecheb Nouredine Chikh M. Ouali Si-Chaïb 《Journal of Mechanical Science and Technology》2011,25(7):1629-1636
This work concerns the characterization of the thermodynamic behavior of the superalloy Airsist 215 (PN 3601669-7) containing
cobalt. Such superalloys are used in aeronautical construction, in the hot parts of the turbine. They are frequently used
for the production of the paddles. The parts in service are subjected to dynamic solicitations and thermal fluctuations over
the course of time. They are responsible for modification and degradation of material properties. This can lead to the appearance
of cracks and, in the long term, to the rupture of these parts. In this paper, a preliminary physical study is made on the
appearance of the cracks, followed by experiments using shocks at ambient temperature and under a heating situation which
simulates combustion. It is found that these dynamic loads have a significant impact on the development of the cracks that
appear on the segments of the turbine nozzle. The study is devoted to the elastic shock of Hertz-Boussinesq extended to viscoelastic
bodies by direct convolution of Riemann-Stielges. The interest resides in the local convolution and the distribution of stresses
in the contact zone. The shock excitation method includes a deduced force in the load and disload phases. This force is an
impulse which approaches a Dirac function. The sample can be modeled approximately by a system of one degree of freedom for
natural frequency, damping and transfer function. The spectral response of the specified shock allows calculation of the damping.
Every point of this spectrum gives the response for the linear system of the transfer function. Then, viscoelastic shock parameters
are deduced. 相似文献
29.
Minh-Tuan Pham Laurent Briançon Daniel Dias Abdelkader Abdelouhab 《Geotextiles and Geomembranes》2018,46(5):611-624
Geosynthetic-reinforced soils constitute an interesting solution for bridging cavities. Many methods have been developed to analyze the stability of soil-geosynthetic-cavity systems, but none of them is able to take into account all the complexities of these mechanisms. Many researchers have assumed mechanisms developed in the reinforced granular platform when cavities appear, such as load transfer and expansion of materials. However, they are not fully understood because many factors can influence the design, such as the cavity opening processes, the type, and the density of the soil.In this study, a new laboratory apparatus is developed to simulate two different cavity opening procedures (trapdoor and progressive opening) for different geometric configurations. A series of tests is conducted for three granular soils with two different geosynthetic sheets. By measuring the shape of the surface soil settlement and the geosynthetic deflection, the expansion coefficient is calculated. A novel tactile pressure sensor is used to observe the load transfer during the cavity opening. The experimental data are analyzed and the influence of the experimental conditions (geometric and soil properties and the opening procedure) are also discussed. Correspondingly, elicited findings can be used to propose recommendations to improve the existing design methods. 相似文献
30.
Abdelkader Frendi 《Numerical Heat Transfer, Part A: Applications》2013,63(5):547-554
Computational tools of turbulent combustion have practical applications for various fields including liquid rocket engines, but some numerical issues are still presented for solving supercritical combustion. In the present study, several of these numerical issues are studied and discussed. Turbulent flow and thermal fields of gaseous hydrogen/cryogenic liquid oxygen flame at supercritical pressure are simulated by a turbulence model. To realize real-fluid combustions, the modified Soave-Redlich-Kwong (SRK) equations of state (EOS) are implemented into the flamelet model with a look-up table as functions of mean and variance of mixture fraction, scalar dissipation rate, enthalpy, and pressure. For supercritical combustion flows, modified forms of the pressure implicit with splitting of operator (PISO) algorithm for solving the pressure-velocity linked equation are introduced. From a comparison of instantaneous temperature distributions for gaseous hydrogen/cryogenic liquid oxygen flame at supercritical pressure, the capability of each method based on the different solution sequence is examined and the effective sequence is explored. The results show that the updated mixture fraction reflected in the pressure correction loop is a critical factor for numerical stability. Also, the relative performance of six convection schemes for supercritical combustion is discussed. 相似文献