A novel strategy based on salp swarm algorithm for extracting the maximum power of proton exchange membrane fuel cell

Cell temperature and water content of the membrane have a significant effect on the performance of fuel cells. The current-power curve of the fuel cell has a maximum power point (MPP) that is needed to be tracked. This study presents a novel strategy based on a salp swarm algorithm (SSA) for extracting the maximum power of proton-exchange membrane fuel cell (PEMFC). At first, a new formula is derived to estimate the optimal voltage of PEMFC corresponding to MPP. Then the error between the estimated voltage at MPP and the actual terminal voltage of the fuel cell is fed to a proportional-integral-derivative controller (PID). The output of the PID controller tunes the duty cycle of a boost converter to maximize the harvested power from the PEMFC. SSA determines the optimal gains of PID. Sensitivity analysis is performed with the operating fuel cell at different cell temperature and water content of the membrane. The obtained results through the proposed strategy are compared with other programmed approaches of incremental resistance method, Fuzzy-Logic, grey antlion optimizer, wolf optimizer, and mine-blast algorithm. The obtained results demonstrated high reliability and efficiency of the proposed strategy in extracting the maximum power of the PEMFC.     

Process optimization and related material properties of silicon films produced by laser-induced chemical vapour deposition from silane

Laser-induced chemical vapour deposition of silicon films on SiO₂/Si (1 0 0) and Si (1 0 0) substrates was studied using ArF laser irradiation of silane/argon gas mixture in parallel to the substrate. The optimal deposition conditions were specified by examination of film morphology at a wide range of irradiation and process parameters. At optimal conditions, specular films were obtained with no powder formation. The effect of deposition parameters, such as laser energy and repetition rate, on the deposition rate and the related film quality, was investigated.     

Absolute Measurements of the Magnetic Field Generated by Different Coils in the Center of EGYPTOR Tokamak

The present work is devoted to measure the absolute magnetic field produced by different coils in the EGYPTOR tokamak using a calibrated pickup coil. Scaling these measurements in different equations connected with the discharge currents from each supply system are performed. The pickup coil used in the present study is well calibrated with Helmholz coils at the IPP in Prague, Czech Republic. A 0.2% deviation has been found between an evaluation done in the present study and the calibration using Helmholz coils. Experimental measurements of the toroidal magnetic field are in good agreement with calculations to within 2%. Very low values of stray magnetic field components arising from TF and OH coils are recorded which proves that the compensation coils for these components are sufficient.     

Proactive resource allocation for asynchronous real-time distributed systems in the presence of processor failures

We present two proactive resource allocation algorithms, RBA^*-FT and OBA-FT, for fault-tolerant asynchronous real-time distributed systems. The algorithms consider an application model where task timeliness is specified by Jensen's benefit functions and the anticipated application workload during future time intervals is described by adaptation functions. In addition, we assume that reliability functions of processors are available a priori. Given these models, our objective is to maximize aggregate task benefit and minimize aggregate missed deadline ratio in the presence of processor failures. Since determining the optimal solution is computationally intractable, the algorithms heuristically compute sub-optimal resource allocations, but in polynomial time. Experimental results reveal that RBA^*-FT and OBA-FT outperform their non-fault-tolerant counterparts in the presence of processor failures. Furthermore, RBA^*-FT performs better than OBA-FT, although OBA-FT incurs better worst-case and amortized computational costs. Finally, we observe that both algorithms robustly withstand errors in the estimation of anticipated failures.     

Knowing Good From Bad: The Paradox of Neuroticism, Negative Affect, and Evaluative Processing.

There are pragmatic benefits to trait-consistent mood states, especially when people are evaluating new objects within the environment (M. Tamir, M. D. Robinson, & G. L. Clore, 2002). The present studies, involving both naturally occurring (Studies 1 and 2) and manipulated (Study 3) mood states, demonstrated such trait-consistent interactions within the context of neuroticism and negative mood states. Individuals high in neuroticism were faster to make evaluations when in a negative mood state like sadness. By contrast, individuals low in neuroticism were faster to make evaluations when in a neutral mood state. The present studies demonstrate that although negative mood states are hedonically unpleasant, they can be beneficial in some ways for individuals high in neuroticism. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Screening for diabetic retinopathy: the utility of nonmydriatic retinal photography in Egyptian adults

BACKGROUND AND OBJECTIVE: Drug resistance has become a major cause of treatment failure in patients with acute leukemia. P-glycoprotein (Pgp), which is associated with the multidrug resistance (MDR) phenotype, has been reported to be an important predictor of treatment outcome. The aim of this study was to analyze the value of Pgp expression in bone marrow or peripheral blood as a predictor of the response to remission induction chemotherapy as well as the duration of remission in patients with de novo acute myeloid leukemia (AML). DESIGN AND METHODS: We examined the expression of Pgp in 82 patients with de novo AML using an immunocytochemical assay with the C219 monoclonal antibody. RESULTS: Twenty-seven of the 82 patients (33%) were C219-positive in from 1% to 100% of their cells. Thirteen cases (16%) showed a positive reaction in more than 50% of the leukemic cells. Only hyperleukocytosis was significantly associated with higher expression of Pgp. Although 8 of the 13 cases (62%) with more than 50% of cells having Pgp expression were CD34-positive, this association was not statistically significant. A univariate analysis of resistance to induction therapy showed a significantly higher resistance rate in patients with increased Pgp expression (P = 0.01) as well as in those patients with decreased reactivity to myeloperoxidase. The multivariate analysis revealed the independent prognostic value of Pgp expression. C219 reactivity did not have an influence on remission duration. INTERPRETATION AND CONCLUSIONS: Our data indicate that P-glycoprotein expression is a reliable marker of resistance to induction treatment in patients with de novo AML.     

A practical approximation algorithm for optimal k-anonymity

k-Anonymity is a privacy preserving method for limiting disclosure of private information in data mining. The process of anonymizing a database table typically involves generalizing table entries and, consequently, it incurs loss of relevant information. This motivates the search for anonymization algorithms that achieve the required level of anonymization while incurring a minimal loss of information. The problem of k-anonymization with minimal loss of information is NP-hard. We present a practical approximation algorithm that enables solving the k-anonymization problem with an approximation guarantee of O(ln k). That algorithm improves an algorithm due to Aggarwal et al. (Proceedings of the international conference on database theory (ICDT), 2005) that offers an approximation guarantee of O(k), and generalizes that of Park and Shim (SIGMOD ’07: proceedings of the 2007 ACM SIGMOD international conference on management of data, 2007) that was limited to the case of generalization by suppression. Our algorithm uses techniques that we introduce herein for mining closed frequent generalized records. Our experiments show that the significance of our algorithm is not limited only to the theory of k-anonymization. The proposed algorithm achieves lower information losses than the leading approximation algorithm, as well as the leading heuristic algorithms. A modified version of our algorithm that issues ℓ-diverse k-anonymizations also achieves lower information losses than the corresponding modified versions of the leading algorithms.     

Mass transfer in an electrochemical reactor with two interacting jets

An electrochemical reactor operated with two identical solution streams injected in opposite directions on the same axis, and leaving it at a normal direction was studied by measuring local and global mass transfer coefficients and visualization of solution flow patterns. This flow configuration was compared to a case where a single stream enters the reactor and leaves it on the same axis. It was found that only the data obtained for the single stream mode can be correlated by the Chilton-Colburn relation, indicating a near laminar boundary layer flow. Global mass transfer coefficients for the single stream mode were found to be slightly higher than those for the interacting jets mode. However, when comparing the two modes by taking into account the dimensionless ratio of the mass transfer coefficient (Sh) to the energy consumption (Eu), it was found that the interacting jets (IJ) mode exhibits a better performance as compared to the single stream mode. The superiority of the IJ mode increases with increasing Reynold's number (Re).Nomenclature A, B adjustable parameters - b half width of channel - C electrolyte ion concentration - d inlet pipe diameter - d microelectrode diameter - D diffusion coefficient - maximum value of mean deviation - E pumping energy - Eu Euler number - F Faraday number - i current to a single microelectrode on an active wall - i current to a single microelectrode in an inert wall - I global diffusion current - k mass transfer coefficient to a single microelectrode in an active wall - k mass transfer coefficient to a single microelectrode in an inert wall - K global mass transfer coefficient - Q volumetric flow rate - Q _T total volumetric flow rate - R radius of the electrochemical reactor - Re Reynolds number - s surface area of a microelectrode - S surface area of the working electrode - Sc Schmidt number - Sh Sherwood number - V _x axial flow velocity alongx-axis - V flow velocity at large distance from the leading edge - V mean flow velocity - x axis tangential to the surface - y axis normal to the surface - z number of electrons transferred in the reaction (z=1 in the present case) Greek letters viscosity - specific gravity - kinematic viscosity (/) - P pressure drop across the reactor - V voltage drop across the reactor Abbreviations ST single stream - IJ interacting jets     

Radiation-induced oxidative degradation of isotactic polypropylene

Gas evolution, oxygen consumption, and change of mechanical properties were studied for the γ-ray irradiation of isotactic polypropylene from ⁶⁰Co under various conditions, such as vacuum, air, and oxygen at room temperature. For irradiation under vacuum, G(H₂) = 2.9 and G (CH₄) = 0.09; the G values for other gases were very small. In the presence of oxygen, G(H₂) was the same, and the G values for other hydrocarbons were two times those under vacuum. The G values of oxidative products and oxygen consumption were G(CO₂) = 2.5, G(CO) = 1.1, and G(O₂) = 50 at oxygen pressure of 500 torr and were dependent on oxygen pressure. With irradiation under vacuum at 2–3 Mrad, mechanical properties scarcely changes immediately after irradiation but degrade gradually with storage time in air at room temperature.