Interactive DE for solving combined security environmental economic dispatch considering FACTS technology

This paper presents an efficient interactive differential evolution (IDE) to solve the multi-objective security environmental/economic dispatch (SEED) problem considering multi shunt flexible AC transmission system (FACTS) devices. Two sub problems are proposed.The first one is related to the active power planning to minimize the combined total fuel cost and emissions, while the second is a reactive power planning (RPP) using multi shunt FACTS device based static VAR compensator (SVC) installed at specified buses to make fine corrections to the voltage deviation, voltage phase profiles and reactive power violation. The migration operation inspired from biogeography-based optimization (BBO) algorithm is newly introduced in the proposed approach, thereby effectively exploring and exploiting promising regions in a space search by creating dynamically new efficient partitions. This new mechanism based migration between individuals from different subsystems makes the initial partitions to react more by changing experiences. To validate the robustness of the proposed approach, the proposed algorithm is tested on the Algerian 59-bus electrical network and on a large system, 40 generating units considering valve-point loading effect. Comparison of the results with recent global optimization methods show the superiority of the proposed IDE approach and confirm its potential for solving practical optimal power flow in terms of solution quality and convergence characteristics.     

Artificial bee colony optimization for economic dispatch with valve point effect

In recent years, various heuristic optimization methods have been proposed to solve economic dispatch (ED) problem in power systems. This paper presents the well-known power system ED problem solution considering valve-point effect by a new optimization algorithm called artificial bee colony (ABC). The proposed approach has been applied to various test systems with incremental fuel cost function, taking into account the valve-point effects. The results show that the proposed approach is efficient and robust when compared with other optimization algorithms reported in literature.     

Experimental study of the effects of a thermal plume entrainment mode on the flow structure: Application to fire

The aim of this work is to experimentally simulate two heat sources of fire, one placed at ground level, the other at a height above the ground, in order to determine the effect of source air entrainment on the resulting flow structure. The development of a free thermal plume was examined by generating a plume produced from an electrically heated disk at a constant temperature. We first studied the behavior of a thermal plume induced by a disk embedded in a horizontal plate placed at the level of the ground. This configuration ensured a regular lateral entrainment of air to the plume. The analysis of the average fields as well as the axial evolution of velocity and temperature showed an important widening of the profiles that encouraged a faster spread of the plume. We then determined the structure of the thermal plume generated by the same source placed at a height above the ground, ensuring simultaneous vertical and lateral entrainment of air into the resulting plume.     

Mate Location Mechanism and Phase-Related Mate Preferences in Solitarius Desert Locust, Schistocerca gregaria

Mate location responses of male and female solitary-reared locusts that had either experienced no crowding or that had been crowded for varying periods were studied in a flatbed wind tunnel. Two hypotheses were explored: that both sexes of this phase of the locust participate in locating the other by using a combination of chemical and visual signals, and that individuals that experience some crowding (i.e., undergo varying levels of phase shift) can compete effectively with their solitary counterparts in mate location and mating. Our results confirm that both male and female solitarious locusts actively participate in mate location, although the former is the more aggressive partner. The responses of the insects are stronger when a visual cue is provided with the olfactory signal. Crowding of solitary-reared adults enhances their responsiveness to the other sex in the absence and presence of the visual cue. This phenomenon may constitute one of several mechanisms that are involved in recruiting solitary individuals into gregarizing groups and facilitating the spread of gregarious characters across a reproductively active solitarious population.     

Assessment of the Electrohydrodynamic Drying Process

Industries using energy-intensive processes are being forced to explore ways for reducing their energy consumption. In the food industry, air drying is one of the more energy-consuming processes. To reduce the energy consumption during this operation, alternative processes should be investigated. One promising alternative consists in the electrohydrodynamic (EHD) enhancement of heat and mass transfer. This paper analyses the literature and describes the great potential of this innovative process based on the generation of an electric wind by a corona discharge. The main aspects of this technique are discussed and special emphasis is given on its benefit for food processes. The main part of this paper concerns experimental investigations carried out to assess the EHD enhancement on the drying process. An experimental set-up was designed to measure the weight losses on a food product submitted to an electrostatic field and to a cross air flow. Present results confirm that, for a low cross air velocity, the ionic wind leads to an enhancement of the drying rate. The best results are obtained for the smaller distance between the food surface and the corona electrode. Nevertheless, the process is less efficient for a high air velocity. The last part deals with a numerical model that was developed to evaluate the electric parameters and the flow field in turbulent regime. This model provides useful information on the coupled phenomena and permits to explain the experimental observations and to help in designing EHD drying processes.     

Active control of natural convection in a fluid layer with volume heat dissipation

A fluid layer subjected to an internal heating source and cooled from above and below is studied. Using linear stability analysis and numerical simulation it is shown that the critical Rayleigh number related to the bifurcation from the motionless conductive state to a convective state can be increased by controlling the heating power. A feedback-control strategy using the deviation of the real fluid temperature from that of the associated conductive state is applied for this purpose.     

CO2 and H2 detection with a CHx/porous silicon-based sensor

There has been great interest in the last years in gas sensors based on porous silicon (PS). Recently, a gas sensing device based on a hydrocarbon CH_x/porous silicon structure has been fabricated. The porous samples were coated with hydrocarbon groups deposited in a methane argon plasma. We have experimentally demonstrated that the structure can be used for detecting a low concentration of ethylene, ethane and propane gases [Gabouze N, Belhousse S, Cheraga H. Phy State Solidi (C), in press].In this paper, the CH_x/PS/Si structure has been used as a sensing material to detect CO₂ and H₂ gases. The sensitivity of the devices, response time and impedance response to different gas exposures (CO₂, H₂) have been investigated.The results show that current-voltage and impedance-voltage characteristics are modified by the gas reactivity on the PS/CH_x surface and the sensor shows a rapid and reversible response to low concentrations of the gases studied at room temperature.     

Fatty Acids in Liver,Muscle and Gonad of three Tropical Rays including Non-Methylene-Interrupted Dienoic Fatty Acids

Scientific investigation of lipids in Elasmobranchs has been conducted mainly on shark species. Because rays seem to be neglected, this study was performed to examine the complete fatty acid (FA) composition with a particular interest for long-chain polyunsaturated FA (PUFA) content in different tissues of three ray species including parts usually discarded. The total FA and PUFA profiles of total lipids were determined in muscle, liver, and gonad of Rhinobatos cemiculus, Rhinoptera marginata, and Dasyatis marmorata, the most often caught ray species from the East Tropical Atlantic Ocean. Fifty FA were characterized as methyl esters and N-acyl pyrrolidides by gas chromatography/mass spectrometry, showing significant levels of 20:5n-3 (EPA) (up to 5.3%) and 22:5n-3 (DPA) (up to 7.3%), high levels of 20:4n-6 arachidonic (ARA) (4.8–8.6% of total FA) and 22:6n-3 (DHA) (up to 20.0%). The results show that muscle, liver and gonad of rays can provide high amounts of essential PUFA, specially DHA, for direct human nutrition or the food processing industry. High proportions of DHA were particularly found in all samples of R. cemiculus (11.6–20.0%), and in muscle and liver of D. marmorata (11.1–16.1%). Regarding the high amounts of (n-3) PUFA, this study shows that these rays deserve a better up-grading, including the normally discarded parts, and describes the occurrence of unusual NMID FA in all tissues studied. Five non-methylene-interrupted dienoic fatty acids (NMID FA) (0–3.4%) were reported, including previously known isomers, namely 20:2 Δ7,13, 20:2 Δ7,15, 22:2 Δ7,13, 22:2 Δ7,15, and new 22:2 Δ6,14. These acids are quite unusual in fish and unprecedented in rays. The 22:2 Δ6,14 acid occurred in gonads of male specimens of R. cemiculus at 2.9%.     

Design Optimization of a New Hot Heat Sink with a Rectangular Fin Array for Thermoelectric Dehumidifiers

The objective of this research was aimed at conducting an experimental investigation to study the heat sink performance of a new rectangular fins array. Various operating conditions were considered, namely the distance between the fan and the fins, varied from 0 mm to 40 mm, heat supplied to the sink and the fan voltage. It was concluded that a fan installed at 30 mm height from the fins is recommended as the hot side temperature was the lowest. Next a pre-experimentation of small scale prototype of thermoelectric Dehumidifier (TED) was designed and constructed. It was composed of two thermoelectric (TE) cooling modules, MT2-1, 6-127, (two in serial) mounted between the rectangular fin heat exchangers with dimension 140 × 240 × 35 mm. The hot side was cooled by a ventilation fan whereas the air flow on the cold side was free convection. The effect of position of fan was investigation experimentally. Preliminary tests confirmed the good performance of the hot heat sink design for the intended thermoelectric application.     

A randomized clustering of anonymous wireless ad hoc networks with an application to the initialization problem

The Distributed Mobility-Adaptive Clustering (DMAC) due to Basagni partitions the nodes of a mobile ad hoc network into clusters, thus giving the network a hierarchical organization. This algorithm supports the mobility of the nodes, even during the cluster formation. The main feature of DMAC is that in a weighted network (in which two or more nodes cannot have the same weight), nodes have to choose the clusterheads taking into account only the node weight, i.e. the mobility when a node weight is the inverse of its speed. In our approach many nodes may have the same speed and hence the same weight. We assume that nodes have no identities and the number of nodes, say n, is the only known parameter of the network. After the randomized clustering, we show that the initialization problem can be solved in a multi-hop ad hoc wireless network of n stations in O(k ^1/2log ^1/2 k)+D _b −1+O(log (max (P _i )+log ²max (P _i )) broadcast rounds with high probability, where k is the number of clusters, D _b is the blocking diameter and max (P _i ), 1≤i≤k, is the maximum number of nodes in a cluster. Thus the initialization protocol presented here uses less broadcast rounds than the one in Ravelemanana (IEEE Trans. Parallel Distributed Syst. 18(1):17–28 2007).