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Synthesis,Characterization and Surface Properties of Amidosulfobetaine Surfactants Bearing Odd-Number Hydrophobic Tail
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S. M. Shakil Hussain Mustapha Alao Animashaun Muhammad Shahzad Kamal Nisar Ullah Ibnelwaleed A. Hussein Abdullah S. Sultan 《Journal of surfactants and detergents》2016,19(2):413-420
Three amidosulfobetaine surfactants were synthesized namely: 3-(N-pentadecanamidopropyl-N,N-dimethyl ammonium) propanesulfonate (2a); 3-(N-heptadecanamidopropyl-N,N-dimethyl ammonium) propanesulfonate (2b), and 3-(N-nonadecanamidopropyl-N,N-dimethyl ammonium) propanesulfonate (2c). These surfactants were prepared by direct amidation of commercially available fatty acids with 3-(dimethylamino)-1-propylamine and subsequent reaction with 1,3-propanesultone to obtain quaternary ammonium salts. The synthesized surfactants were characterized by IR, NMR and mass spectrometry. Thermogravimetric analysis (TGA) results showed that the synthesized surfactants have excellent thermal stability with no major thermal degradation below 300 °C. The critical micelle concentration (CMC) values of the surfactants 2a and 2b were found to be 2.2 × 10?4 and 1.04 × 10?4 mol/L, and the corresponding surface tension (γCMC) values were 33.14 and 34.89 mN m?1, respectively. The surfactants exhibit excellent surface properties, which are comparable with conventional surfactants. The intrinsic viscosity of surfactant (2b) was studied at various temperatures and concentrations of multi-component brine solution. The plot of natural logarithm of relative viscosity versus surfactant concentration obtained from Higiro et al. model best fit the surfactant behavior. Due to good salt resistance, excellent surface properties and thermal stability, the synthesized surfactant has potential to be used in various oil field applications such as enhanced oil recovery, fracturing, acid diversion, and well stimulation. 相似文献
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Guthrie John T.; Van Meter Peggy; Hancock Gregory R.; Alao Solomon; Anderson Emily; McCann Ann 《Canadian Metallurgical Quarterly》1998,90(2):261
The authors define reading engagement as the mutual support of motivations, strategies, and conceptual knowledge during reading. To increase reading engagement, a collaborative team designed a year-long integration of reading/language arts and science instruction (Concept-Oriented Reading Instruction, CORI). The authors compared students who received this instruction to similar students who received traditionally organized instruction aimed toward the same objectives. A path analysis showed that CORI had a positive effect on strategy use and text comprehension for students at Grades 3 and 5 when accounting for past achievement and prior knowledge. CORI also had a positive, indirect effect on conceptual knowledge mediated by strategy use, and this instruction facilitated conceptual transfer indirectly through several paths simultaneously. The findings are discussed in relation to a growing literature on instructional contexts for motivated strategy use and conceptual learning from text. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
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Glick Peter; Fiske Susan T.; Mladinic Antonio; Saiz José L.; Abrams Dominic; Masser Barbara; Adetoun Bolanle; Osagie Johnstone E.; Akande Adebowale; Alao Amos; Annetje Barbara; Willemsen Tineke M.; Chipeta Kettie; Dardenne Benoit; Dijksterhuis Ap; Wigboldus Daniel; Eckes Thomas; Six-Materna Iris; Expósito Francisca; Moya Miguel; Foddy Margaret; Kim Hyun-Jeong; Lameiras Maria; Sotelo Maria José; Mucchi-Faina Angelica; Romani Myrna; Sakalli Nuray; Udegbe Bola; Yamamoto Mariko; Ui Miyoko; Ferreira Maria Cristina; López Wilson López 《Canadian Metallurgical Quarterly》2000,79(5):763
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Abdur-Rasheed Alao Mohamed Konneh 《The International Journal of Advanced Manufacturing Technology》2012,58(9-12):949-967
Conventional grinding of silicon substrates results in poor surface quality unless they are machined in ductile mode on expensive ultra-precision machine tools. However, precision grinding can be used to generate massive ductile surfaces on silicon so that the polishing time can be reduced immensely and surface quality improved. However, precision grinding has to be planned with reliability in advance and the process has to be performed with high rates of reproducibility. Therefore, this work reports the empirical models developed for surface parameters R a, R max, and R t with precision grinding parameters, depths of cut, feed rates, and spindle speeds using conventional numerical control machine tools with Box–Behnken design. Second-order models are developed for the surface parameters in relation to the grinding parameters. Analysis of variance is used to show the parameters as well as their interactions that influence the roughness models. The models are capable of navigating the design space. Also, the results show large amounts of ductile streaks at depth of cut of 20?μm, feed rate of 6.25?mm/min, and spindle speed of 70,000?rpm with a 43-nm R a. Optimization experiments by desirability function generate 37-nm R a, 400-nm R max, and 880-nm R t with massive ductile surfaces. 相似文献
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Study of the corrosion processes at the primary oil refining by Mössbauer and X-ray investigation – II. Water condensator und separators Samples from the tube bundle surface of a water condensator and from benzene-water separators in an operating installation for primary oil refining are investigated. The compositions of the samples and the types of corrosion on the technological route of the refined oil were established on the basis of Mössbauer spectroscopy and X-ray diffraction analysis. 相似文献
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Olubukola D. Adekola Onyedikachi Kenny Udekwu Oluwatobi Tolulope Saliu Damilola Williams Dada Stephen O. Maitanmi Victor Odumuyiwa Olujimi Alao Monday Eze Funmilayo Abibat Kasali Ayokunle Omotunde 《计算机系统科学与工程》2022,41(3):875-890
The applications of information technology (IT) tools and techniques have, over the years, simplified complex problem solving procedures. But the power of automation is inhibited by the technicality in manning advanced equipment. To this end, tools deliberately combating this inhibition and advancing technological growth are the Unmanned Aerial Vehicles (UAVs). UAVs are rapidly taking over major industries such as logistics, security, and cinematography. Among others, this is a very efficient way of carrying out missions unconventional to humans. An application area of this technology is the local film industry which is not producing quality movies primarily due to the lack of technical know-how in utilizing these systems. This study therefore aim to devise an autonomous object tracking UAV system that would eliminate the complex procedure involved in stabilizing an aerial camera (aerial bot) midair and promote the creation of quality aerial video shooting. The study adopted Unified Modeling Language (UML) tools in modeling the system’s functionality. The traditional Server-Client model architecture was adopted. The OpenCV library employed proved highly efficient in aiding the tracking procedure. The system provided a usable web controller which provides easy interaction between the pilot and the drone. Conclusively, investments in UAVs would enhance creation of quality graphic contents. 相似文献
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Matthew P. Grindle Ben Carter John Paul Alao Katherine Connors Riina Tehver Andrea N. Kravats 《International journal of molecular sciences》2021,22(4)
The 70 kDa and 90 kDa heat shock proteins Hsp70 and Hsp90 are two abundant and highly conserved ATP-dependent molecular chaperones that participate in the maintenance of cellular homeostasis. In Escherichia coli, Hsp90 (Hsp90) and Hsp70 (DnaK) directly interact and collaborate in protein remodeling. Previous work has produced a model of the direct interaction of both chaperones. The locations of the residues involved have been confirmed and the model has been validated. In this study, we investigate the allosteric communication between Hsp90 and DnaK and how the chaperones couple their conformational cycles. Using elastic network models (ENM), normal mode analysis (NMA), and a structural perturbation method (SPM) of asymmetric and symmetric DnaK-Hsp90, we extract biologically relevant vibrations and identify residues involved in allosteric signaling. When one DnaK is bound, the dominant normal modes favor biological motions that orient a substrate protein bound to DnaK within the substrate/client binding site of Hsp90 and release the substrate from the DnaK substrate binding domain. The presence of one DnaK molecule stabilizes the entire Hsp90 protomer to which it is bound. Conversely, the symmetric model of DnaK binding results in steric clashes of DnaK molecules and suggests that the Hsp90 and DnaK chaperone cycles operate independently. Together, this data supports an asymmetric binding of DnaK to Hsp90. 相似文献
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