The electrochemical behavior of low carbon steel (API 5L grade B) in 1 mol/L HCI solution with different concentrations of N,Nr-bis(4-formylphenol)-trimethylenediamine Schiff base was studied by electrochemical techniques and density functional theory analysis. The inhibition efficiency was found to increase with increasing inhibitor concentration and decreased with increasing temperature. The high inhibition efficiency was attributed to the blocking of active sites by adsorption of inhibitor molecules on the steel surface. Thermodynamic parameters for the adsorption and activation processes were determined. Galvanostatic polarization data indicated that Schiff base act as a mixed-type inhibitor and the adsorption isotherm obeyed the Langmuir adsorption isotherm. Results obtained from quantum chemical studies show excellent correlations between the quantum chemical parameters and the experimental inhibition efficiencies using density functional theory at the B3LYP/6-31G(d,p) and B3LYP/3-21G basis set levels and ab initio calculations using HF/6-31G(d,p) and HF/3-21G methods. 相似文献
The growing prevalence of droughts and water scarcity have increased the importance of operating dam and reservoir systems efficiently. Several methods based on algorithms have been developed in recent years in a bid to optimize water release operation policy, in order to overcome or minimize the impact of droughts. However, all of these algorithms suffer from some weaknesses or drawbacks – notably early convergence, a low rate of convergence, or trapping in local optimizations – that limit their effectiveness and efficiency in seeking to determine the global optima for the operation of water systems. Against this background, the present study seeks to introduce and test a Hybrid Algorithm (HA) which integrates the Gravitational Search Algorithm (GSA) with the Particle Swarm Optimization Algorithm (PSOA) with the goal of minimizing irrigation deficiencies in a multi-reservoir system. The proposed algorithm was tested for a specific important multi-reservoir system in Iran: namely the Golestan Dam and Voshmgir Dam system. The results showed that applying the HA could reduce average irrigation deficiencies for the Golestan Dam substantially, to only 2 million cubic meters (MCM), compared to deficiency values for the Genetic Algorithm (GA), PSOA and GSA of 15.1, 6.7 and 5.8 MCM respectively. In addition, the HA performed very efficiently, reducing substantially the computational time needed to achieve the global optimal when compared with the other algorithms tested. Furthermore, the HA showed itself capable of assuring a high volumetric reliability index (VRI) to meet the pattern of water demand downstream from the dams, as well as clearly outperforming the other algorithms on other important indices. In conclusion, the proposed HA seems to offer considerable potential as an optimizer for dam and reservoir operations world-wide.
Geoelectrical surveys were conducted in Area 3 of the Gol-e-Gohar iron ore mine to provide geological and hydrogeological information. Open pit mining is currently underway in the northern part of the Area, and underground mining operations are planned for the southern section. Groundwater has already been encountered in the open pit mine. Twenty five resistivity soundings were first performed in the mine area; then, induced polarization (IP) measurements were carried out to remove ambiguities between clay and water-bearing layers. To investigate fault zones as water conduits, combined resistivity profiling surveys were also carried out. These measurements provided a detailed structural map of the pit area. Resistivity and IP results have subsequently been confirmed by observations at three monitoring wells and the mine pit wall. Monitoring and piezometric wells will be drilled at locations suggested by the results of the geoelectrical surveys. Drainage galleries may be developed to dewater the open pit mine. However, another option being considered is to start the underground mining with the idea that it will initially simply serve as a dewatering mechanism. 相似文献
The levels of C-reactive protein (CRP) in sera of 71 HIV-seropositive children and of 71 apparently healthy children were determined by Mancini method. The results demonstrate that HIV-infection per se doesn't increase the concentration of CRP in serum. After this we wanted to determine the relationship between CRP and evolution of HIV-infection. For this we used a set of 8 children in different stages of HIV-infection. For each child we had at least 2 sera, used for diagnosis and CRP assay. Three children (one with AIDS [correction of SIDA] and 2 in intermediate stage) had elevated levels of CRP. The reason for these elevations were an acute salmonellosis, a febrile episode of unknown origin and for the last child, once a staphylococcal infection of the skin and once an acute bronchiolitis clinically but not microbiologically documented. In conclusion, HIV-infection per se doesn't induce increased levels of the CRP, in any stage; this protein could be used as a marker of bacterial, parasitic and cytomegalovirus infections. 相似文献
Water Resources Management - Reservoirs’ optimal operation is a critical issue in the management of surface water resources. In the present study, after combining the whale optimization... 相似文献
Oleuropein (OLEU) is an important indicator of the quality and authenticity of extra virgin olive oils (EVOO). Electrochemical sensors and biosensors for the detection of oleuropein can be used to test the adulteration of extra virgin olive oils. The present study aimed at the qualitative and quantitative determination of oleuropein in commercial EVOO samples by applying electrochemical techniques, cyclic voltammetry (CV) and square wave voltammetry (SWV). The sensing devices used were two newly constructed enzyme biosensors, supported on single-layer carbon-nanotube-modified carbon screen-printed electrode (SPE/SWCNT) on whose surface tyrosinase (SPE/SWCNT/Tyr) and laccase (SPE/SWCNT/Lac) were immobilized, respectively. The active surfaces of the two biosensors were analyzed and characterized by different methods, cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and Fourier transform infrared spectroscopy (FTIR) and the results confirmed the efficient immobilization of the enzymes. SPE/SWCNT/Tyr was characterized by a low detection limit (LOD = 9.53 × 10−8 M) and a very good sensitivity (0.0718 μA·μM−1·cm−2) over a wide linearity range from 0.49 to 11.22 μM. The process occurring at the biosensor surface corresponds to kinetics (h = 0.90), and tyrosinase showed a high affinity towards OLEU. The tyrosinase-based biosensor was shown to have superior sensitive properties to the laccase-based one. Quantitative determination of OLEU in EVOOs was performed using SPE/SWCNT/Tyr and the results confirmed the presence of the compound in close amounts in the EVOOs analysed, proving that they have very good sensory properties. 相似文献