Investigation of structure and conductivity properties of polyaniline synthesized by solid–solid reaction

Conductive polyaniline has been prepared by solid–solid reaction using ammonium peroxydisulfate as an oxidant. The obtained polymer was examined by X-ray diffraction, UV visible, FTIR spectroscopy, thermogravimetric analysis and impedance spectroscopy. The effect of oxidant/monomer molar ratio (R) on the structure and electrical properties of polymer has been examined. The analyses of X-ray diffraction patterns demonstrated that polyaniline prepared by this method is more crystalline than that obtained by conventional solution method. The FTIR spectroscopy showed that the emeraldine salt has been formed. The electrical properties were measured at different temperatures in the range of 296–523 K. The ac conduction shows a regime of constant dc conductivity at low frequencies and a crossover to a frequency-dependent regime of the type A ω^S at high frequencies.     

Autonomous hybrid system and coordinated intelligent management approach in power system operation and control using hydrogen storage

Autonomous hybrid power systems are attractive research questions that deliver electricity to isolated consumers without being connected to the power grid. The deployment of autonomous hybrid power systems is considered as an option to improve energy security. For this reason, the main objective is to ensure the efficient production of electricity without interruption. To achieve this goal, we have proposed an accurate simulation system in which a solar energy component serves as a primary load supply, and an energy recovery component is based on a fuel cell. A long-term energy storage component comprises a water electrolyzer which is considered a primary storage and an ultracapacitor storage component deployed as a short-term storage of energy. To achieve the correct system operation, a new schema approach for intelligent energy management based on a multi-agent system is developed and discussed. The main task is to define the architecture of the multi-agent system and to define the functions of all the agents according to the characteristics of the energy needs and the production costs. Thus, in order to prove the reliability and effectiveness of the applied control strategy and its impact on the operation of the system, the proposed system is simulated using the Matlab/Simulink environment by referring to an extracted experimental database of the Tunisian Meteorological Service.     

Non-hydrolytic sol–gel route to a family of hybrid mesoporous aluminosilicate ethanol dehydration catalysts

Journal of Materials Science - Hybrid materials are intensely studied for potential applications in heterogeneous catalysis. Organic groups at the catalyst surface can modify not only its...     

Interactions between Acetoin,a Plant Volatile,and Pheromone In <Emphasis Type="Italic">Rhynchophorus palmarum</Emphasis>: Behavioral and Olfactory Neuron Responses

Aggregation of Rhynchophorus palmarum weevils on host plants is mediated by a male pheromone (rhynchophorol: R) and host-plant volatiles (PVs) acting in synergy. Synthetic PV blends synergizing pheromone contain acetoin (A) and ethyl acetate (EtAc). R, A, and EtAc are detected by specialized olfactory receptor neurons (ORNs). In addition, particular types of ORNs are tuned to both A and R. To specify the role played by acetoin in pheromone perception, we recorded the responses of ORNs to 100 ng of A or R presented either separately or mixed. Behavioral responses to R, A, and EtAc were studied in a four-armed olfactometer and by field trapping. We screened 59 R-, A-, and AR-tuned ORNs by recording specific responses to odors presented either separately or mixed. Stimulations by blends elicited complex response profiles from the three ORN types: some gave synergistic responses, others were inhibited, and the remainder responded as though both odors were detected independently. Several gave either a weak or no response to a first stimulation by R, but responded clearly to a second stimulation after an intercalary stimulation by A. In the olfactometer, both sexes were more attracted to a blend of A + R (1 + 0.01 ng/sec) than to pure compounds, whereas EtAc did not enhance response to R. Pheromone-baited traps (1 mg/day) containing PV blends (650 mg/day) based on an ethanol/EtAc blend (1:1), plus either 5 or 10% A, or a more complex reference blend, or sugarcane (natural pheromone synergist), caught similar numbers of weevils and about twice as many insects as a control ethanol/EtAc blend. Traps with only pheromone caught about 10 times fewer insects. Behavioral results support the role of acetoin as a pheromone synergist for R. palmarum, and electrophysiological data provide evidence of modulation of peripheral sensory responses to pheromone by acetoin. Sexual dimorphism was observed neither at the ORN nor at the behavioral levels.     

Selective maintenance optimisation for series-parallel systems alternating missions and scheduled breaks with stochastic durations

This paper deals with the selective maintenance problem for a multi-component system performing consecutive missions separated by scheduled breaks. To increase the probability of successfully completing its next mission, the system components are maintained during the break. A list of potential imperfect maintenance actions on each component, ranging from minimal repair to replacement is available. The general hybrid hazard rate approach is used to model the reliability improvement of the system components. Durations of the maintenance actions, the mission and the breaks are stochastic with known probability distributions. The resulting optimisation problem is modelled as a non-linear stochastic programme. Its objective is to determine a cost-optimal subset of maintenance actions to be performed on the components given the limited stochastic duration of the break and the minimum system reliability level required to complete the next mission. The fundamental concepts and relevant parameters of this decision-making problem are developed and discussed. Numerical experiments are provided to demonstrate the added value of solving this selective maintenance problem as a stochastic optimisation programme.     

New Algorithms of Control and Observation of the Induction Motor Based on the Sliding-Mode Theory

In this article new algorithms are developed for controllers of speed and flux and non-linear observer’s of induction motor’s. These new algorithms are based on the sliding-mode theory. The use of the non-linear sliding mode method provides best performances for motor operation and robustness of the control law despite the external and internal perturbations. To prove the accuracy of the results, validation is made with Adnan’s experimental results. Later a parametric study is presented to evaluate the speed and flux variation according to the increase in time for both open and closed loops. From the parametric study, it should be noted that the variation of the electrical parameters does not affect the stability of the system. Finally, it is concluded that results of the developed algorithms showed an excellent stability of the system confirmed by best quality numerical simulations.     

New Composite Electrode Material Based on Glassy Carbone/Polythiophene/MnO2

In this paper, it presents the work which consists to develop and characterize a modified electrode with a conductive polymer film, poly [3-methyl thiophene] then incorporating manganese dioxide MnO2 into the film. The deposition of the polymer film on the surface of the glassy carbon electrode is realized by the electrochemical oxidation of the monomer [3-methyl thiophene] in an organic medium. Then the electrode obtained was immersed in a solution containing ions Mn4~ to introduce into the polymeric film. The technique of insertion of manganese ions is performed by interaction with the polymer film. The electrochemical oxidation of the modified electrode in an aqueous medium will precipitate the manganese dioxide in the form of particles in the polymer film. In this study, it was found that several parameters affect the amount of manganese dioxide introduced as the pH of the medium and the thickness of the polymer film.     

Proteomic characterisation of subclover seed storage proteins during germination

BACKGROUND: Early seedling development is a critical step in the establishment of subclover (Trifolium subterraneum), an economically important and widespread pasture legume. In this study the seed storage proteome of this non‐model species was characterised in mature dry seeds and during imbibition by using two‐dimensional electrophoresis coupled with tandem mass spectrometry. RESULTS: The phenol‐extracted proteome of subclover dry seeds consisted of 97 polypeptide spots displayed within a window of pI 3–10 and molecular mass 10–150 kDa. De novo sequencing coupled with MS BLAST search enabled the confident identification of 61 proteins, which corresponded to 59 7S vicilin‐ and two 11S legumin‐type globulins. The experimental mobility of vicilin isoforms along with peptide mapping indicated that low‐molecular‐mass polypeptides might account for the post‐translational proteolysis of small vicilin subunits according to the model described for those of pea. Analysis of quantitative changes in the seed storage proteome upon imbibition showed that vicilin catabolism according to a site‐specific process was favoured during early seedling growth in T. subterraneum. CONCLUSION: The establishment of a seed proteome map for T. subterraneum pointed to vicilins as dominant proteins in mature seeds whose catabolism features during early seedling growth may be of relevance under environmental conditions. Copyright © 2009 Society of Chemical Industry     

Power unit SOFC-MTG model in Electromagnetic Transient Software PSCAD

In the world energy scene in recent years, there has been a tendency towards electric power generation through an integration of alternatives sources. In this context, fuel cells are considered a new type of generating unit that has the ability to generate electrical power through direct conversion of fuels. In the case of stationary electric power generation, the solid oxide fuel cell is interesting, since it can be powered directly by natural gas, and has a high efficiency when compared to thermal machines; yet their exhaust gases have a temperature and pressure suitable for insertion in gas microturbines, which increases the system's efficiency. This study looks at the modeling of the solid oxide fuel cell and gas microturbine as well as the performance analysis from simulations in Electromagnetic Transient Software (PSCAD/EMTDC).