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61.
Khalid S. M. El Karsani Ghaithan A. Al‐Muntasheri Abdullah S. Sultan Ibnelwaleed A. Hussein 《应用聚合物科学杂志》2014,131(23)
Polyacrylamide (PAM) and its derivatives are the most commonly used polymers in the preparation of polymeric gels for water control in petroleum reservoirs. This study involved the use of polyethylenimine (PEI) as a crosslinker for PAM. In this study, we investigated PAM alkaline hydrolysis at high temperatures. The effects of salts [sodium chloride (NaCl) and ammonium chloride (NH4Cl)] on the degree of hydrolysis (DH) of PAM were investigated. These salts were used as retarders to elongate the gelation time of the PAM/PEI system. The data obtained from 13C‐NMR was used to understand the retardation mechanisms by salts. We found that NH4Cl accelerated the extent of hydrolysis more in comparison with NaCl. Moreover, the apparent viscosity of the hydrolyzed samples was measured. PAM hydrolysis in the presence of NH4Cl resulted in a lower solution viscosity than that in the presence of NaCl. Therefore, NH4Cl was more effective in shielding negative charges on the carboxylate groups of the partially hydrolyzed polyacrylamide (PHPA) chain. NaCl and NH4Cl were compatible with the PHPA/PEI system, but sodium carbonate showed a white precipitate. In addition, high‐temperature/high‐pressure elastic modulus data were reported for the first time for this system. Differential scanning calorimetry was coupled with rheology to explain the PAM/PEI crosslinking in the presence of salts. Models were developed to assess the impact of the salts on the PAM DH and the induction period before gelation. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41185. 相似文献
62.
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64.
Syazwan Afif Mohd Zobir Zulkarnain Zainal Mohd Zobir Hussein 《Materials Chemistry and Physics》2010,124(1):477-481
The effect of the addition of very small amount of polyvinyl alcohol (PVA) on the resulting physicochemical properties of ZnO synthesized by ethylene glycol-hydrothermal method was studied. Significant change in particle size distribution and specific surface area can be observed even only 0.02% PVA (w/w) was added into the ethylene glycol (EG) solution, in which the median particle size distribution increased from 5 to 8 nm and at the same time the specific surface area is also increased to nearly 50%. Further addition of PVA resulted in the decrease of the specific surface area due to the formation of agglomeration and aggregation of particles as observed by FESEM study. This study shows that the presence of minute amount of polymer, PVA plays very crucial role in determining the resulting properties of the synthesized ZnO by EG-hydrothermal method. 相似文献
65.
A. Aguilar-Arevalo M. Blecher D.A. Bryman J. Comfort J. Doornbos L. Doria A. Hussein N. Ito S. Kettell L. Kurchaninov C. Malbrunot G.M. Marshall T. Numao R. Poutissou A. Sher B. Walker K. Yamada 《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》2009,609(2-3):102-105
An extension of the TRIUMF M13 low-energy pion channel designed to suppress positrons based on an energy-loss technique is described. A source of beam channel momentum calibration from the decay π+→e+ν is also described. 相似文献
66.
Elyas Sadeq Alaghbari Zulkarnain Zainal Imad Hamadneh Mohd Zobir Bin Hussein Mohd Haniff Bin Wahid 《Journal of Superconductivity and Novel Magnetism》2012,25(2):255-260
Zn- and Ca-doped ErBa2Cu3O7−δ
were successfully prepared via coprecipitation method using metal acetates as the starting salts. The precipitated samples
were calcined for 20 h at 900 °C and sintered at 920 °C for 24 h. All heat treatments were carried out under oxygen environment.
Results show that there is a selectivity of the doping site depending on the ionic radius of the dopant. Furthermore, increase
in the critical temperature, T
c
, was observed in 0.05 mole of calcium and zinc doped samples. The difference in ionic radius of the dopant led to the increase
in porosity as the ionic radius decreases. On the other hand, structural distortion increased as the difference of ionic radius
became larger. 相似文献
67.
Shadpour Mallakpour Mohammad Zhiani Abdolvahid Barati Hussein Rostami 《International Journal of Hydrogen Energy》2013
The present investigation deals with the fabrication of new poly(vinyl alcohol)/titanium dioxide (PVA/TiO2) nanocomposites (NCs) with different titanium dioxide (TiO2) loading by using ultrasound irradiation. For the improvement of nanoparticles (NPs) dispersion and increasing possible interactions between NPs and PVA, the surface of TiO2 NPs was modified by γ-aminopropyltriethoxy silane. The as-prepared NCs were characterized by spectroscopic, thermogravimetric analysis and electron microscopy methods. The results demonstrate that NPs dispersed homogeneously within the PVA matrix on nanoscale, which could be assigned to the hydrogen and covalent bonds formed between PVA and NPs. The results indicated that heat stability of NCs was improved in the presence of modified TiO2 NPs. The mechanisms of surface modification and a possible mechanism of ultrasonic induced interaction between polymer and NPs have been analyzed. 相似文献
68.
Hussein A. Abbass 《Soft Computing - A Fusion of Foundations, Methodologies and Applications》2006,10(8):687-698
When an optimization problem encompasses multiple objectives, it is usually difficult to define a single optimal solution.
The decision maker plays an important role when choosing the final single decision. Pareto-based evolutionary multiobjective optimization (EMO) methods are very informative for the decision making process since they provide the decision maker with a set of efficient
solutions to choose from. Despite that the set of efficient solutions may not be the global efficient set, we show in this
paper that the set can still be informative when used in an interactive session with the decision maker. We use a combination
of EMO and single objective optimization methods to guide the decision maker in interactive sessions. 相似文献
69.
Samer Dessouky Eyad Masad Dallas Little Hussein Zbib 《Canadian Metallurgical Quarterly》2006,132(2):158-171
This paper presents the development of a methodology for microstructure analysis and modeling of hot mix asphalt (HMA). This methodology relies on using effective local material properties and strain gradient theory in the finite element analysis of HMA microstructure. The effective local properties are calculated using an analytical micromechanical model that captures the influence of percent of particles on the microscopic response of HMA. Strain gradient elasticity is used in order to account for the effect of particle size in the finite element analysis. The autocorrelation function and the moving window technique are used to determine the microstructure characteristic length scales that are used in strain gradient elasticity. A number of asphalt mixes with different aggregate types and size distributions are analyzed in this paper. 相似文献
70.
A. A. Hussein 《Metallurgical and Materials Transactions A》1982,13(5):837-846
Dual-phase (α + martensite) microstructures were produced in binary Cu-Al alloys by quenching from the (α + β) phase field.
A wide range of martensite volume fraction VM was obtained, depending on alloy composition and quench temperatureT. Linear dependence onT of VM was established. Predefined values for VM can thus be achieved by adjustment ofT and alloy composition. Furthermore, the size, shape, and distribution of component phases can be varied in a predetermined
fashion by means of controlled cooling from the β range. The properties of α and martensite were tracedvia microhardness measurements. The microhardness of martensite increases with quench temperature in spite of the accompanying
decrease of its solute content. This is in accord with previous work and emphasizes the dominating role of martensite ordered
structure on strength. Such strength depends only on quench temperature irrespective of overall alloy composition or morphology.
The α microhardness is not affected by alloy composition or quench temperature. The martensitic phase can be hardened by means
of short time tempering due to order hardening or solute clustering effects. Depending on quench temperature, optimum use
of such temper hardening can be achieved. Moreover, cold working of dual-phase structures followed by annealing at temperatures
around 300 °C achieves substantial strengthening of both α and martensite. The strengthening of α is a consequence of anneal
hardening. Although such high strength levels are accompanied by reduction of the ductility (as measured by thickness reduction
achieved by cold rolling), the heat treatment schedule can be optimalized to achieve high strength while restoring ductility. 相似文献