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71.
Benzoxazinone 2 was prepared and reacted with formamide,acetamide,some primary aromatic amines and heterocyclic amines giving the corresponding quinazolone derivatives 3-15 respectively.The reaction of benzoxazinone 2 with hydrazine hydrate and phenyl hydrazine was also studied.Representative compounds of the synthesized products were evaluated as antioxidants and corrosion inhibitors for gasoline engine lubricating oil.The highest antioxidant activities were obtained with compounds 10-15.The optimum concentration recommended for these new additives was found to be 0.lg for 1L ofoil for compounds 13-15.In addition,some of the highly effective antioxidant additives,namely 10-15,were thermally analyzed by using thermogravimetric analysis (TGA) and differential thermal gravimetric analysis (DTGA) techniques and the results indicated that compounds are thermally stable and could be used under thermal conditions.Moreover,a comparison of the oxidation stability between the tested oil containing the prepared products and lubricating oil containing commercial additives was also studied. 相似文献
72.
Ahmad Awais Ahmad Mudassar Habib Muhammad Asif Sarwar Shahzad Chaudhry Junaid Latif Muhammad Ahsan Dar Saadat Hanif Shahid Muhammad 《The Journal of supercomputing》2019,75(4):2269-2288
The Journal of Supercomputing - The main challenge in database-as-a-service is the security and privacy of data because service providers are not usually considered as trustworthy. So, the data... 相似文献
73.
The optimization of the total annual cost in heat exchanger networks has been one of the overarching goals when synthesizing these networks. Several methodologies and techniques have been developed to achieve optimal costs in mixed material heat exchanger networks. This paper demonstrates the application of two decomposition methodologies (total decomposition and partial decomposition) for typical cost rules. The objective function was defined as the optimization and minimization of the total annual cost in mixed materials heat exchanger network. Three optimization algorithms, hybrid genetic‐particle swarm optimization (GA‐PSO), shuffled frog leaping algorithm (SFLA) techniques, and ant colony optimization (ACO), were used to further optimize the total cost in mixed materials heat exchanger network. The results indicate that the total annual cost in partial decomposition method was smaller than that in full integration method and total decomposition method. The reduction of the total annual cost was about 27% for GA‐PSO algorithm, 24% for SFLA and 10% for ACO relative to the results reported in this work. In partial decomposition method, at least one mixed material of heat exchanger was used to reduce the hot and cold utility for decreasing the total annual cost. Partial decomposition method resulted in the highest reduction of the total annual cost compared with other methods. Percentage of difference of the total annual cost were 0.36%, 1.92%, and 5.05% for full integration, total decomposition, and partial decomposition methods, respectively, in comparison with the previous studies. Results have been compared with the results of other studies to demonstrate the accuracy of the applied algorithms. 相似文献
74.
75.
Medhat A. Nemitallah Ahmed A. Abdelhafez Asif Ali Ibrahim Mansir Mohamed A. Habib 《国际能源研究杂志》2019,43(14):7790-7822
The use of fossil fuel is expected to increase significantly by midcentury because of the large rise in the world energy demand despite the effective integration of renewable energies in the energy production sector. This increase, alongside with the development of stricter emission regulations, forced the manufacturers of combustion systems, especially gas turbines, to develop novel combustion techniques for the control of NOx and CO2 emissions, the latter being a greenhouse gas responsible for more than 60% to the global warming problem. The present review addresses different burner designs and combustion techniques for clean power production in gas turbines. Combustion and emission characteristics, flame instabilities, and solution techniques are presented, such as lean premixed air‐fuel (LPM) and premixed oxy‐fuel combustion techniques, and the combustor performance is compared for both cases. The fuel flexibility approach is also reviewed, as one of the combustion techniques for controlling emissions and reducing flame instabilities, focusing on the hydrogen‐enrichment and the integrated fuel‐flexible premixed oxy‐combustion approaches. State‐of‐the‐art burner designs for gas turbine combustion applications are reviewed in this study, including stagnation point reverse flow (SPRF) burner, dry low NOx (DLN) and dry low‐emission (DLE) burners, EnVironmental burners (including EV, AEV, and SEV burners), perforated plate (PP) burner, and micromixer (MM) burner. Special emphasis is made on the MM combustor technology, as one of the most recent advances in gas turbines for stable premixed flame operation with wide turndown and effective control of NOx emissions. Since the generation of pure oxygen is prerequisite to oxy‐combustion, oxygen‐separation membranes became of immense importance either for air separation for clean oxy‐combustion applications or for conversion/splitting of the effluent CO2 into useful chemical and energy products. The different carbon‐capture technologies, along with the most recent carbon‐utilization approaches towards CO2 emissions control, are also reviewed. 相似文献
76.
Mouna Hamouda Insaf Handous Nasr Ben Dhia Samia Ayachi Ahmed Letaief Sabra Aloui Ammeur Frih Habib Skhiri Habib Khochtali Mezri Elmay 《Hemodialysis international. International Symposium on Home Hemodialysis》2012,16(4):497-503
Brown tumors (BTs) are relatively uncommon but they are serious complications of renal osteodystrophy. The objective of this study was to analyze the clinical, biological, and radiological characteristics of 16 patients with BTs provoked by secondary hyperparathyroidism (sHPT) and its response to the decrease in parathyroid hormone levels after parathyroidectomy (PTX). The management of that uncommon condition was also reviewed. We conducted a retrospective study including 16 end‐stage renal disease patients who underwent subtotal PTX between 1997 and 2007 for severe sHPT with BTs. Our study included 10 men and 6 women, whose average age was 34 years. All patients were on dialysis. Ten of them were on dialysis for more than 5 years. The median duration on dialysis was 84 months. Patients included suffered from swellings associated with functional limitations. BTs had multiple locations in 7 patients. Jaw was the most frequent location (62%). Radiography and tomodensitometry demonstrated a mixed radio lucent and radio‐opaque lesions with an expansion of the cortical bone. Bone scan demonstrated an increased uptake of lesions. Chirurgical treatment was indicated in all cases because of severe refractory sHPT with functional limitations and/or disfiguring deformities. In all cases, BTs stopped its progression and even decreased in size. However, it was insufficient in four cases, which required a surgical resection. PTX remains an efficacious approach in resistant cases of sHPT with persistent BTs. 相似文献
77.
Elnaz Asghari Maryam Gholizadeh-Khajeh Habib Ashassi-Sorkhabi 《Journal of Materials Engineering and Performance》2016,25(10):4230-4238
Because of the major limitations in drinking water resources, the industries need to use unprocessed water sources for their cooling systems; these water resources contain major amount of hardening cations. So, mineral scales are formed in cooling water systems during the time and cause major problems. The use of green anti-scaling materials such as carboxylic acids is considered due to their low risks of environmental pollution. In the present work, the scale inhibition performance of tartaric acid as a green organic material was evaluated. Chemical screening tests, cathodic and anodic voltammetry measurements and electrochemical impedance spectroscopy (EIS), field emission scanning electron microscopy (FESEM), energy-dispersive x-ray and x-ray diffraction, were used for the evaluation of the scale inhibition performance. The results showed that tartaric acid can prevent calcium carbonate precipitation significantly. The hard water solution with 2.0 mM of tartaric acid indicated the highest scale inhibition efficiency (ca. 68%). The voltammetry, EIS and FESEM results verified that tartaric acid can form smooth and homogeneous film on steel surface through formation of Fe(III)-tartrate complexes and retard the local precipitation of calcium carbonate deposits. 相似文献
78.
Protective properties of PPy‐Au nanocomposite coatings prepared by sonoelectrochemisty and optimized by the Taguchi method 下载免费PDF全文
The polypyrrole (PPy) and polypyrrole‐Au (PPy‐Au) nanocomposite films have been sonoelectrochemically synthesized on St‐12 steel electrodes using the galvanostatic technique. Experimental design according to the Taguchi method has been applied to optimize the factors on the synthesis of PPy‐Au nanocomposite coating. Three factors were used to design an orthogonal array L9: Synthesis time (t), Current density (I), and Concentration of HAuCl4 (C). The synthesized Au nanoparticles during polymerization were characterized by Ultraviolet–visible (UV‐visible) spectroscopy. Characterization of the surfaces was done by scanning electron microscope (SEM), energy dispersive X‐ray spectrum (EDX), and atomic force microscope (AFM). The scanning electron microscopy (SEM) image of PPy shows a smooth surface while PPy‐Au nanocomposite film has a compact morphology. Moreover, energy dispersive X‐ray spectrum (EDX) is evidence for the incorporation of Au nanoparticles. The corrosion protection of coatings was investigated by open circuit potential (OCP) time trends, potentiodynamic polarization technique, and electrochemical impedance spectroscopy (EIS) in a NaCl 3.5% solution. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41087. 相似文献
79.
The compatibilization of recycled polypropylene (PP) and high-density polyethylene (HDPE) was studied using two types of compatibilizers: 5 wt% PP-grafted-maleic anhydride (5 wt% MAPP) and 5 wt% HDPE-grafted-maleic anhydride (5 wt% MAHDPE), using a cone and plate rheometer. Maleic anhydride (MAH) was grafted onto PP or HDPE via peroxide initiated melt grafting technique. Blends containing highest amount of pure HDPE exhibited maximum values for tensile strength, complex viscosity, dynamic and loss modulus compared to similar blends developed using recycled HDPE. The latter properties of all the compatibilized blends were higher compared to that of uncompatibilized blends. Studies on rheology of the pure and recycled polymer and its compatibilized blends have thrown some light on the molecular weight distribution of these materials. High shear yielding characteristics were noted for MAHDPE compatibilized blends containing high percentage of HDPE. Scanning electron microscopy showed that blends containing a high percentage of HDPE and HDPE based compatibilizer exhibit a dispersed morphology. Fourier transform infrared spectrometer characterization was conducted to check if compatibilization occurred between recycled PP and HDPE. 相似文献
80.
Optically variable windows (smart windows), which control the transmission of light into buildings and vehicles, are of interest both for the control of solar heat load and for privacy applications. Such windows are likely to utilize electrochromic technology to achieve optical control. An electrochromic device consisting of a cathodically colouring tungsten trioxide (WO3) film, an anodically colouring Prussian blue (PB) film, and a polymer electrolyte was made. The polymer electrolyte was prepared from polyvinyl alcohol doped with H3PO4 and KH2PO4 to accommodate the conduction of both H+ and K+ ions. The electrochromic WO3 and PB films functioned in a complementary way such that the device was coloured or bleached by the application of –0.5 V or +0.5 V (WO3 films vs PB film), respectively. The spectral characteristics of the coloured device confirmed the complementary colouration of WO3 and PB in the device. 相似文献