Iranian Polymer Journal - Hydrogels were produced from mixtures of polyvinyl alcohol (PVA), polyvinyl pyrrolidone (PVP), and acrylic acid (AAc) using γ-radiation at doses of 3, 7, and... 相似文献
In reservoir system operation, optimization is very much essential and the compatibility of different optimization techniques is essential to be checked by some performance checking indices. In this study, various types of performance-measuring index are used and compared to provide a complete knowledge on adopting different approaches. Here, the considered performance-measuring indicators will check the operation policy in terms of three different scenarios—how the method is efficient in achieving best results (reliability); how vulnerable the method is for different critical situation (vulnerability); and how capable it is to handle a failure of the model (resiliency). Therefore, the study proposed the artificial bee colony (ABC) optimization technique to develop an optimal water release policy for the well-known Aswan High Dam, Egypt. Particle swarm optimization, genetic algorithm and neural network-based stochastic dynamic programming are also used in a view of comparing model performances. A release curve is developed for every month as a guidance to the decision maker. Simulation has been done for each method using historical actual inflow data, and reliability, resiliency and vulnerability are measured. All model indicators proved that the release policy provided by ABC optimization outperforms in terms of achieving minimum water deficit, less waste of water and handling critical situations.
A simplified generalized finite difference solution using MATLAB has been developed for steady‐state heat transfer in a bar, slab, cylinder, and sphere. Solutions are given for all types of boundary conditions: temperature and flux boundary conditions. A generalized solution for 2D heat transfer in a slab is also developed. Solutions have been compared with analytical solutions and there is very good agreement between computed and analytical solutions. The solution can easily be extended to similar types of situations in fluid flow and mass transport operations. 相似文献
The Kansas Department of Transportation has a comprehensive pavement management system known as network optimisation system (NOS). Annual condition surveys are conducted for NOS. Currently, the structural number (SN) of flexible pavements is computed using the American association of state highway and transportation officials equation based on the centre and fifth sensor deflections of a falling weight deflectometer (FWD). However, a rolling wheel deflectometer (RWD) can be used to collect deflection data at the network-level. This study was conducted to see whether the SN of flexible pavements can be obtained from this RWD deflection and NOS condition survey results. In this study, FWD deflection data, collected from 1998 to 2006, were analysed. Multiple regression analysis was done. The results showed that there is a negative relationship between SN and centre deflection. Equations can be used to calculate SN based on FWD (or RWD) centre deflections and network-level condition survey results. The SN is more sensitive to centre deflection than the total pavement thickness. 相似文献
Development of lithium disilicate-based glass-ceramics critically depends on use of nucleating agent in the glass matrix. The present study reports the effect of externally added nucleating agent Li3PO4 in Li2O–K2O–MgO–ZnO–ZrO2–Al2O3–SiO2 system which is compared with a reference composition (GC1) (SiO2:Li2O = 2.16:1) prepared with in situ formed Li3PO4. For externally added Li3PO4, two compositions were studied. In one case (GC2) before addition of Li3PO4, SiO2:Li2O ratio in glass was maintained as 2.87:1 and in another case (GC3) SiO2:Li2O ratio in glass was maintained same as reference GC1 that is, 2.16:1. The glasses were characterized by using MAS-NMR spectroscopy. Sintering and crystallization behavior of the glass-ceramics was characterized by using XRD, SEM, DTA. Due to in situ formation of Li3PO4, GC1 resulted in a dense sample with finer crystals of lithium disilicate. In GC2 and GC3, externally added lithium phosphate, which was in the form of ultrafine aggregated particles, formed flower-like colonies of radially outward crystals. Higher SiO2:Li2O ratio in GC2 resulted in lithium disilicate crystals and high viscous glass causing large air entrapment and so less densification. GC3 with higher lithia in glass showed higher densification than GC2 but only lithium metasilicate crystals were formed. 相似文献
Dry (CO2) reforming of methane is conducted over two newly synthesized Ni20/Ce-γAl2O3 and Ni20/Ce-meso-Al2O3 catalysts. The x-ray diffraction (XRD) patterns indicated that Ni20/Ce-meso-Al2O3 exhibits a better dispersion of nickel, while Ni20/Ce-γAl2O3 has larger amounts of nickel crystallites. The temperature programmed desorption (TPD) kinetics analysis indicated that Ni20/Ce-meso-Al2O3 had a lesser metal-support interaction than the Ni20/Ce-γAl2O3. The thermal gravimetric analysis (TGA) indicated that the incorporation of ceria into the Al2O3 matrix helps to stabilize Ni20/Ce-meso-Al2O3 during dry reforming of methane. The temperature programmed reduction (TPR) indicated that the synthesized catalysts were sufficiently reducible below 750 °C. A fixed bed reactor evaluation (at 750 °C) showed that both catalysts can facilitate methane reforming to syngas with minimal coking throughout the 30 hours time-on-stream (TOS). However, Ni20/Ce-meso-Al2O3 is more promising in terms of prolonged stability for dry reforming applications. Moreover, the syngas yield for Ni20/Ce-γAl2O3 is close to equilibrium prediction during the first 1 hour of reaction time. 相似文献
Food Analytical Methods - A simple, rapid and sensitive GC-MS method using on-column injection was developed and validated to determine ergosterol (ERG) levels in maize and wheat. In this method,... 相似文献
We studied the elemental analysis, structural morphology, mechanical, and electrical properties of carbon nanoparticles synthesized from diesel. The spherical carbon particle size in the range of about 10 to 80 nm in diameter was observed in scanning electron microscope (SEM) studies that were identified by Atomic force microscopy (AFM) study as an aggregation of carbon particles of average size 2.5 nm. The surface rms of carbon nanoparticle thin film (CNTF) was measured directly by AFM and found 0.22 nm. The Derjaguin–Muller–Toporov (DMT) elastic modulus of carbon nanoparticles (CNPs) was measured by PeakForce QNM mode of AFM. The minimum and maximum elastic modulus was measured of 0.40 GPa and 43.89 GPa, respectively. The resistivity, conductivity, magneto resistance, mobility, and average Hall co-efficient were measured by “Ecopia Hall-effect measurement system” by four-point Van der Pauw approach at ambient condition. We demonstrated I–V characteristic at the Indium/CNTF thin film interface, which is accompanied by rectifying behavior. 相似文献