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31.
Mehrdad Massoudi 《International Journal of Non》2003,38(3):313-336
In the mechanics of multiphase (or multicomponent) mixtures, one of the outstanding issues is the formulation of constitutive relations for the interaction force. In this paper, we give a brief review of the various relations proposed for this interaction force. The review is tilted toward presenting the works of those who have used the mixture theory (or the theory of interacting continua) to derive or to propose a relationship for the interaction (or diffusive) force. We propose a constitutive relation which is general and frame-indifferent and thus suitable for use in many flow conditions. At the end, we provide an alternative approach for finding the drag force on a particle in a particulate mixture. This approach has been used in the non-Newtonian fluid mechanics to find the drag force on surfaces. 相似文献
32.
Adsorption of Metanil Yellow Azoic Dye from Aqueous Solution onto Mg‐Fe‐NO3 Layered Double Hydroxide
Dr. Kamellia Nejati Zolfaghar Rezvani Mahsa Mansurfar Abolfazl Mirzaee Mehrdad Mahkam 《无机化学与普通化学杂志》2011,637(11):1573-1579
We report the preparation and characterization of a layered double hydroxide (LDH) adsorbent for azoic dye, metanil yellow (yellow GX; YGX) removal. The nanoparticles of Mg‐Fe‐LDH‐NO3 adsorbent were prepared with Mg/Fe molar ratio of 3:1 by a hydrothermal process and coprecipitation method at pH 9.5 and were characterized by X‐ray powder diffraction (XRPD), thermal gravimetric analysis (TGA), elemental analysis, and Fourier transform infrared spectroscopy (FT‐IR). The size and morphology of nanoparticles were examined by scanning electron microscopy (SEM). The XRD patterns indicate that the intercalation of YGX between the LDH layers has not occurred and surface adsorption has happened. In the adsorption experiments, the Gibbs free energy ΔG0 values, the enthalpy ΔH0, and entropy ΔS0 was determined. The isotherms showed that the adsorption of YGX by Mg‐Fe‐LDH‐NO3 was both consistent with Langmuir and Freundlich equations. 相似文献
33.
Hematite nanoparticles have been successfully synthesized via two processing routes:(i) conventional precipitation route and (ii) reverse microemulsion route.The particle precipitation was carried out in a semibatch reactor.A microemulsion system consisting of water,chloroform,1-butanol and surfactant was loaded with iron nitrates to form iron nanoparticles precipitation.The precipitation was performed in the single-phase microemulsion operating region.Three technical surfactants,with different structure and HLB value are employed.The influence of surfactant characterization on the size of produced iron oxide particle has been studied to gain a deeper understanding of the important controlling mechanisms in the formation of nanoparticles in a microemulsion.Transmission electron microscopy (TEM),surface area,pore volume,average pore diameter,pore size distribution and XRD were used to analyze the size,size distribution,shape and structure of precipitated iron nanoparticles. 相似文献
34.
Atekeh Tarahhomi Mehrdad Pourayoubi Arnold L. Rheingold James A. Golen 《Structural chemistry》2011,22(1):201-210
Different orientations of P(O) versus C(O) in P(O)NHC(O) skeleton have been discussed in two new phosphorus(V)-nitrogen compounds
with formula XP(O)Y and XP(O)Z2 where X = NHC(O)C6H4(4-F) and Y = NHCH2C(CH3)2CH2NH (1), Z = NHC6H4(4-CH3) (2). Compound 1 is the first example of an aliphatic diazaphosphorinane with a gauche orientation which has been studied by X-ray crystallography; the P=O bond is in the equatorial position of the ring. Both
compounds show
n
J(F,C) and
m
J(F,H) coupling constants (n = 1, 2, 3 and 4; m = 3 and 4) and 3
J(P,C) > 2
J(P,C). Quantum chemical calculations were performed with HF and Density Functional Theory (DFT) methods using 6−31+G(d,p)
basis set. A tentative assignment of the observed vibrational bands for these molecules is discussed. Compound 1 shows a deshielded C atom of the carbonyl moiety (in 13C NMR spectrum) relative to that of 2, which is supported by IR spectroscopy in which the considerably lower C=O frequency is observed for 1. Comparing the X-ray crystallography and IR spectra of 1 and 2 shows that the acyclic compound 2, containing P=O and C=O bonds in an anti position, are involving in a stronger N–H···O=P hydrogen bond in crystal network. This leads to a weaker P=O and NC(O)NHP(O)–H bonds and stronger N···O interaction. The Namide–H is involved in an intramolecular N–H···O hydrogen bond. 相似文献
35.
36.
Direct mechanical force is used to create a temporary shape in shape memory polymers. This can become difficult in situations where the sample is not directly accessible such as interior in the body. In these cases it is not possible to use a direct mechanical force to deform the sample into temporary shape; therefore other alternative routes should be proposed. The magnetic force is a good candidate for inducing remote deformation. The ability of magnetic field to cause deformation in soft matters has already been revealed. To prove the hypothesis of using magnetic force to create temporary shape, magnetic field active shape memory polymeric nanocomposites were manufactured by incorporation of NdFeB ferromagnetic micro particles in a nanocomposite based on crosslinked low density polyethylene loaded with 2 wt.% of organoclay. The results indicate that as the NdFeB content increases, the reversible temporary deformation induced in the samples by the magnetic force increases. The effect of NdFeB concentration on the shape recovery progress and the possibility of heat induction in NdFeB filled samples through the application of an alternating magnetic field were also examined. 相似文献
37.
Liebner F Pour G de la Rosa Arranz JM Hilscher A Rosenau T Knicker H 《Angewandte Chemie (International ed. in English)》2011,50(37):A34-A39
Nitrogen (N) is a major nutrient element controlling the cycling of organic matter in the biosphere. Its availability in soils is closely related to biological productivity. In order to reduce the negative environmental impact, associated with the application of mineral N-fertilizers, the use of ammonoxidised technical lignins is suggested. They can act as potential slow N-release fertilisers which concomitantly may increase C sequestration of soils by its potential to bind CO?. The idea of our study was to combine an improved chemical characterisation of ammonoxidised ligneous matter as well as their CO?-binding potential, with laboratory pot experiments, performed to enable an evaluation of their behaviour and stability during the biochemical reworking occurring in active soils. 相似文献
38.
Mohammad Rezaiee-Pajand Mehrzad Sharifian Mehrdad Sharifian 《European Journal of Mechanics - A/Solids》2011,30(3):345-361
Up to now, some explicit approximate integration schemes based on exponential maps, for non-hardening material obeying Drucker–Prager’s criterion, have been presented. Two new exponential-based approximate formulations, for associative Drucker–Prager plasticity are developed in this article. Both are consistent and explicit algorithms. The linear isotropic and Prager’s kinematic hardening behavior are assumed. Furthermore, an accurate solution for the constitutive equations is derived. The accuracies of the suggested approximate algorithms are assessed by creating related iso-error maps. In addition, by using piecewise strain load histories, and calculating computation times, the robustness and efficiency of the formulations are demonstrated. 相似文献
39.
Wayland E. Noland Mary J. Walhstrom Michael J. Konkel Mark E. Brigham Annette G. Trowbridge Lisa M. C. Konkel Ronald P. Gourneau Cheryl A. Scholten Nina H. Lee John J. Condoluci Todd S. Gac Mehrdad Mostafaei Pour Peter M. Radford 《Journal of heterocyclic chemistry》1993,30(1):81-91
Tetrahydrocarbazoles have been prepared in one-flask syntheses from indoles, ketones or aldehydes, and maleimides, with acid catalysis. The reactions involve a condensation of the indole with the ketone or aldehyde, followed by an in situ trapping of the vinylindole in a Diels-Alder addition with a maleimide. Isomerization of the double bond into the indole nucleus gave the tetrahydrocarbazoles which were isolated ( 6, 9 , and 10 ). Variation of the indole, carbonyl compound, and maleimide has been explored. The predominant stereochemistry of the tetrahydro ring in the products is all-cis, although a second stereoisomer has been isolated. Two regioisomers were generated from all unsymmetrical 2-alkanones, except 2-butanone, which gave the single isomer 9a . Aromatization of tetrahydrocarbazoles 6 to carbazoles 7 was accomplished with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone. 相似文献
40.
Noll's rule is used to determine the structure of a material symmetry group written with respect to one reference configuration when the representation of the symmetry with respect to another configuration is the traditional material symmetry group associated with isotropy, transverse isotropy or orthotropy, and for an arbitrary deformation gradient relating the two configurations. It is shown that the former symmetry group can contain an orthogonal subgroup. It is determined whether this subgroup is that for isotropic, transversely isotropic, orthotropic, monoclinic, or triclinic response, and the preferred directions of the symmetry are determined. 相似文献