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61.
Modified and nonmodified blends of linear low-density polyethylene (PE) and polypropylene (PP) form separated phases of crystalline PP and PE. They form spherulitic crystals in the core, but highly oriented nonspherulitic phases at the skin of injection molded test bars. The dimension of the spherulites decreases with increasing PE content within the blends. Crystallization behavior of both crystalline phases is influenced by the other phase. The crystallization temperature of PP is increased in the presence of the compatibilizer. Transmission electron micrographs of blends modified by poly(styrene-block-ethylene/butylene) (SEBS) and stained by OsO4 showed co-continuous lamellar structure of the blends with a polypropylene phase containing the majority of the modifier. Smaller portions of the modifier can be found on the surface of the two olefinic phases as dispersed spheres, with an average diameter of 50–90 nm. The lamellar structure is independent of the spherulitic structure, and interpenetrates the spherulites. The conclusion of this study is that this block copolymer, while improving the physical properties of the blends, is not a true compatibilizer of the system according to the conventional terminology of physical chemistry. 相似文献
62.
Samira Sadat Abolmaali Ali Tamaddon Haniye Najafi Rasoul Dinarvand 《Journal of Inorganic and Organometallic Polymers and Materials》2014,24(6):977-987
The study was aimed to investigate the effect of chemical modification of branched poly ethyleneimine (PEI) on chelation of transition metal ions (Me2+) including Zn2+, Cu2+ or Ni2+ and sol–gel conversion thereof. To modulate chelation property of PEI, imidazole moieties were introduced into the polymer backbone by carbodiimide chemistry at different molar ratios of fmoc-protected l-histidine. The synthesis was characterized by 1H-NMR spectroscopy and size exclusion chromatography. Potentiometric titration of PEI/Me2+ aqueous dispersions showed formation of stable complexes at pH above 5 depending on the degree of l-histidine substitution. FT-IR spectroscopy showed the imidazole ring of l-histidine was involved in the coordination interactions between PEI and Me2+. Addition of Zn2+ to PEI solution induced sol–gel conversion at a critical molar ratio decreasing by a higher degree of l-histidine modification. The gelation process led to formation of stable globular nanostructures as confirmed by atomic force microscopy with projected mean diameters less than 200 nm. Cellular experiment showed that l-histidine substitution enhanced cyto-compatibility of PEI, moreover cytotoxicity decreased significantly upon coordination of Zn2+ with the polymers. Conclusively, the coordination complexes of Zn2+ and l-histidine substituted PEI could serve as a nano system for biomedical applications. 相似文献
63.
Rasoul Chaharmiri Alireza Fallahi Arezoodar 《Journal of Mechanical Science and Technology》2016,30(5):2005-2010
Electromagnetic forming (EMF) is a high strain rate forming technology which can effectively deform and shape high electrically conductive materials at room temperature. In this study, the electromagnetic and mechanical parts of the process simulated using Maxwell and ABAQUS software, respectively. To provide a link between the software, two approaches include ‘loose’ and ‘sequential’ coupling were applied. This paper is aimed to investigate how sequential coupling would affect radial displacement accuracy, as an indicator of tube final shape, at various discharge voltages. The results indicated a good agreement for the both approaches at lower discharge voltages with more accurate results for sequential coupling, but at high discharge voltages, there was a non-negligible overestimation of about 43% for the loose coupling reduced to only 8.2% difference by applying sequential coupling in the case studied. Therefore, in order to reach more accurate predictions, applying sequential coupling especially at higher discharge voltages is strongly recommended. 相似文献
64.
65.
Mohammad Mehdi Ahmadi Seyed Rasoul Mirghaderi 《The Structural Design of Tall and Special Buildings》2020,29(7)
The through plate connection has a practical reliable configuration for fully restrained connections for a steel I‐beam to hollow or concrete‐filled tubular columns in seismic areas. Based on experimental programs of authors on interior planar moment connections via through plate technique, this paper presents the outcome of the studies focusing on the joint behavior and the shear transfer in the panel zone of through plate connection. Based on the conducted approved three full‐scale tests, the behavior of connection components and panel zone shear force were investigated accurately in order to provide useful information and key parameters to facilitate design calculations and proportioning the connection. The contribution of each component in the total shear capacity of the panel zone region was determined. Load transfer mechanisms were explained and by quantifying the portion of load transfer paths, the calculation approach was described for design purpose. The proposed design procedure was validated for a wide range of beam to column connections using finite element models. Verified numerical models were used to conduct parametric studies. The numerical results revealed that the proposed analysis method can predict well the induced demand in the connection components and also the design procedure is suitable and secure for all cases. 相似文献
66.
Mohammadreza Naeimirad Ali Zadhoush Richard Kotek Rasoul Esmaeely Neisiany Saied Nouri Khorasani Seeram Ramakrishna 《应用聚合物科学杂志》2018,135(21)
There has been a steady progress in developing synthetic fibers in the past few years. Bicomponent fibers and nanofibers in a core/shell (C/S) configuration, including two dissimilar materials have presented unusual potential for use in many novel applications. These fibers can be produced using a variety of materials via different techniques i.e., coaxial melt spinning and electrospinning. In this review, we discuss the recent advances in C/S fibers and nanofibers’ production. The first part has been assigned to the bicomponent fibers manufacturing technology, while production and applications of C/S nanofibers have been described in the second part. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46265. 相似文献
67.
Rasoul Moradi Saeed Mahruz Monfared Younes Amini Abolfazl Dastbaz 《Korean Journal of Chemical Engineering》2016,33(7):2160-2168
Electrospun hybrid membranes were synthesized using electrospinning of Poly (vinylidenefluoride) - titanium tetraisopropoxide (PVDF-TTIP) sol. Asymmetric post-treatment of membrane conducted for deprotonation of titanate and making hydrophilic/hydrophobic dual characteristics. The membranes were characterized by various methods such as wettability, scanning electron microscopy, infrared spectroscopy, X-ray diffraction and liquid entry pressure tests. For evaluating the separation performance, these membranes were applied in the VMD process to treat water heavy metal contaminants. The effects of operating parameters such as flow rate, temperature and membrane properties as porosity, on contaminant removal and producing ultra-pure water have been studied. 相似文献
68.
69.
The removal of cationic dyes from aqueous solutions by adsorption onto pistachio hull waste 总被引:1,自引:0,他引:1
The efficacy of pistachio hull powder (PHP) prepared from agricultural waste was investigated in this study as a novel adsorbent for the elimination of dye molecules from contaminated streams. Removal of methylene blue (MB) as a cationic model dye by PHP from aqueous solution was studied under different experimental conditions. The selected parameters were solution pH (2–10), PHP dosage (0.5–3 g/L), MB concentrations (100–400 mg/L), contact time (1–70), and solution temperature (20–50 °C). The experimental results indicated that the maximum MB removal could be attained at a solution pH of 8. The dosage of PHP was also found to be an important variable influencing the MB removal percentage. The removal efficiency of MB improved from 94.6 to 99.7% at 70 min contact time when the MB concentration was decreased from 300 to 100 mg/L at a pH and PHP dosage of 8 and 1.5 g/L, respectively. The kinetic analysis showed that the pseudo-second-order model had the best fit to the experimental data. The Langmuir equation provided the best fit for the experimental data of the equilibrium adsorption of MB onto PHP at different temperatures. In addition, the maximum adsorption capacity increased from 389 to 602 mg/g when the temperature was increased from 20 to 50 °C. The thermodynamic evaluation of MB adsorption on PHP revealed that the adsorption phenomenon under the selected conditions was a spontaneous physical process. Accordingly, pistachio hull waste was shown to be a very efficient and low-cost adsorbent, and a promising alternative for eliminating dyes from industrial wastewaters. 相似文献
70.
The catalytic oxidation of hydrazine was investigated by a cobalt(II) bis (benzoylacetone) ethylenediimino multi wall carbon nanotube-modified carbon paste electrode (Co(II)BBAEDI-MWCNT-MCPE) as a highly sensitive electrochemical sensor. The effect of variables such as pH and modifier percent on cyclic voltammograms peak current was optimized. The modified electrode showed very efficient electrocatalytic activity for anodic oxidation of hydrazine in 0.1 M phosphate buffer solution (pH 7.0). Anodic peak potential of hydrazine oxidation at the surface of modified electrode shifts by about 500 mV toward negative values compared with that on the bare electrode. The diffusion coefficient and electron transfer coefficient of hydrazine were obtained using electrochemical approaches. The Co(II)BBAEDI-MWCNT-MCPE showed good reproducibility (RSD < 3.3%). The electrocatalytic current increased linearly with the hydrazine concentration in the range of 0.3–70.0 μM and detection limit was 0.1 μM. The effect of various interferences on the hydrazine peak current was studied. This method was applied to determine hydrazine in water samples. 相似文献