Decision aid function for restoration of transmission power systems after a blackout

This thesis, based on a project realised in cooperation with Électricité de France (EDF), proposes a new concept for a Decision Aid Function FOr Restoration (DAFFOR) of transmission power systems after a blackout. DAFFOR is an interactive computer tool which provides the operators in power system control centres with guidance concerning the actions to execute during the restoration, in real-time conditions. In other words, it takes into account the real-time state of the power system, including the unforeseen events that may happen during the restoration. Since time is a limiting factor and the decision making is a highly combinatorial problem, a knowledge-based system is proposed in order to solve it. The restoration process can be decomposed into two main stages. The first one, skeleton creation, consists of starting the production units and connecting some transmission devices in order to energize a strong network. The second stage, load pickup, aims to supply the consumers. In DAFFOR, EDF's strategy for the first restoration stage has been implemented, and a new strategy for the load pickup stage has been proposed and implemented in the form of rules. The above restoration strategies represent DAFFOR's knowledge, which has been enhanced with a number of heuristics. DAFFOR consists of two kernels: the Reasoning kernel and the Real Time Update kernel. The Reasoning kernel has the task of assisting the operator during the restoration process and is the interactive guidance part of DAFFOR. It can either suggest a control action to execute on the power system to the operators or assess a control action provided by the operators. The control action is suggested with respect to operating limits (over- and under-voltages, frequency excursions and overloads) and according to knowledge (restoration strategy and heuristics). The feasibility of an action is tested within an internal dynamic simulator, which also takes into account the time necessary to physically execute an action (e.g., telephone a person in the field). The Reasoning kernel can adapt its operation via data generated by the Real Time Update (RTUpd) kernel. The RTUpd kernel steadily reads real-time power system data from System Control and Data Acquisition (SCADA) function and those entered by the operators (if unavailable from SCADA). It generates a coherent data set, which is the only real-time information available to the Reasoning kernel, and the message which indicates to the Reasoning kernel how to continue its operation. In addition to the real-time data, the RTUpd kernel has two feedback inputs internal to DAFFOR: a coherent data set generated in the previous data processing by the RTUpd kernel itself, and a simulated data set generated by the Reasoning kernel (i.e., its internal dynamic simulator). With these three inputs, the RTUpd kernel generates the current image of the power system, and identifies unforeseen events. Thanks to the RTUpd kernel, the Reasoning kernel may keep up with the dynamic evolution of the power system. The stand-alone prototype of DAFFOR has been tested with data provided by EDF, and shown very good efficiency. At present, it is about to be coupled with the EDF's operator training simulator in order to test its real-time functionality. This work also proposes an original method aimed at the determination of a strategy for the load pickup stage. A genetic algorithm has been developed which generates the optimized sequences of manoeuvres for different initial states of the power system for the second restoration stage. It uses the dynamic simulator as its evaluation function. The obtained results have shown that some additional manipulations should be done in order to deduce generic rules for the load pickup strategy. At present, the obtained sequences are classified in a decision tree, which permits the most adequate sequence for the initial state to be chosen

Photocatalytic efficiency of ZnFe-mixed metal oxides in correlation with reaction parameters

In the last decade, the interest for the photocatalytic phenomena has rapidly grown due to its great potential for the overall environmental decontamination. Photocatalysts based on ZnFe mixed oxides have been considered to be potentially photocatalyticly efficient in wastewater purification. This investigation is focused on the characterization of the synthesized and thermally treated photocatalysts, on their photocatalytic efficiency in the degradation process of organic dye pollutant Rhodamine B (RhB), as well as on the influence of process parameters on the photocatalytic efficiency. The results showed that the obtained mixed oxides are highly efficient in the RhB degradation. In addition, the pH effect of the reaction system on the photocatalytic activity was observed, which could be explained by the correlation with different textural and structural properties of the photocatalysts

Adsorption kinetics for the removal of methyl orange using adsorbents based on Zn Al-layered double hydroxides

The adsorption phenomena of adsorbents based on ZnAl layered double hydroxides was studied. Methyl orange was used as test pollutant. The emphasis of the study was the analysis of Methyl Orange removal kinetics. The synthesized and thermally treated adsorbents were characterized by X-ray diffraction. The analysis of adsorption kinetics was conducted using the pseudo-second order kinetic model. The results showed that the samples have adsorptive removal properties, particularly the adsorbent derived from thermally treated layered double hydroxides. The findings give an insight into the adsorption phenomena of ZnAl-layered double hydroxides based materials which could be considered as promising adsorbents for the removal of Methyl Orange in wastewaters

Compression and strength behaviour of viscose/polypropylene nonwoven fabrics

Compression and strength properties of viscose/polypropylene nonwoven fabrics has been studied. Compressionbehavior of the nonwoven samples (sample compressibility, sample thickness loss & sample compressive resilience) havebeen analyzed considering the magnitude of applied pressure, fabric weight, fabric thickness, and the porosity of thesamples. Based on the calculated porosity of the samples, pore compression behavior (pore compressibility, porosity loss &pore compressive resilience) are determined. Equations for the determination of pore compressibility, porosity loss, and porecompressive resilience, are established. Tensile strength and elongation as well as bursting strength and ball traverseelongation are also determined. The results show that the sample compression behavior as well as pore compressionbehavior depend on the magnitude of applied pressure. At the high level of applied pressure, a sample with highercompressibility has the lower sample compressive resilience. Differences in pore compressibility and porosity loss betweeninvestigated samples have also been registered, except in pore compressive resilience. Sample with the higher fabric weight,higher thickness, and lower porosity shows the lower sample compressibility, pore compressibility, sample thickness loss,porosity loss, and tensile elongation, but the higher tensile strength, bursting strength, and ball traverse elongation

Quality of clothing fabrics in terms of their comfort properties

Quality of various clothing woven fabrics with respect to their comfort properties, such as electro-physical properties, air permeability, and compression properties has been studied. Fabrics are produced from cotton and cotton/polyester fibre blends in plain, twill, satin and basket weave. Results show that cotton fabrics have lower values of the volume resistivity, air permeability and compressive resilience but higher values of effective relative dielectric permeability and compressibility as compared to fabrics that have been produced from cotton/PES fibre blends. Regression analysis shows a strong linear correlative relationship between the air permeability and the porosity of the woven fabrics with very high coefficient of linear correlation (0.9807). It is also observed that comfort properties are determined by the structure of woven fabrics (raw material composition, type of weave) as well as by the fabrics surface condition. Findings of the studies have been used for estimating the quality of woven fabrics in terms of their comfort properties by the application of ranking method. It is concluded that the group of cotton fabrics exhibits better quality of comfort as compared to the group of cotton/PES blend fabrics.

Application of the adsorbent CR-100 for Ammonium Removal: Thermodynamic and Kinetic Studies

Groundwater with increased ammonia concentration is a constant concern regarding the preparation of drinking water. The affinity of ammonia to be adsorbed on the surface of different solid materials significantly influences the selection of its removal process and has been the motivation for this investigation. Crystal-Right™ (CR-100) was used for the removal of ammonia from aqueous solution in batch adsorption procedure. The kinetics of adsorption followed the pseudo-second-order model. The Elovich model suggested that chemisorption rate decreased with the temperature increase. The liquid film diffusion and intra-particle diffusion models revealed that heterogeneous adsorbent surface energy had a particularly pronounced impact on the overall mass transfer rate. The Arrhenius and Eyring’s equations suggested spontaneous and endothermic nature of complex adsorption/ion exchange removal process. The isosteric heat of adsorption revealed that with the increase in surface loading lateral interactions between the adsorbed molecules occurred

Uv light impact on phthalates migration from children's toys into artificial saliva

Phthalates has been widely used in children?s toys as plastic plasticizers and softeners. Therefore, attention should be paid to plastic toys, especially those that children can put in their mouths. In this paper quantification of five phthalates: DMP, DnBP, BBP, DEHP and DnOP in plastic toys, as well as irradiation of toys with UV light was performed. After sample preparation and development of the liquid?liquid phthalate extraction method from artificial saliva phthalate quantitative determination using the GC?MS technique was performed. The mean recovery value for DEHP is 77.03?2.76 %. The determination of phthalate in the recipient models (artificial saliva and n-hexane) was performed after 6, 15 and 30 days of the migration test using the GC?MS technique. Based on the known mass % DEHP in the analyzed toys, the percentage of phthalate migration from each analyzed toy to the recipient model after 6, 15 and 30 days of the migration test was calculated. The results show that there is no significant migration of DEHP into artificial saliva, due to high polarity of the recipient (artificial saliva is polar), unlike n-hexane where the migration of DEHP is significant because it is a non-polar solvent

Psychophysical stress disturbs expression of mitochondrial biogenesis markers in hypothalamus and adenohypophysis

Summary. Although psychophysical stress is widespread in human society and a major contributor to a range of pathological conditions, it is not known if this form of stress regulates mitochondrial biogenesis in the hypothalamus or adenohypophysis, the main organs involved in compensatory specifc response of the organism to stress (so called “fght or flight” response). Accordingly, this study was designed to evaluate the effects of acute and repeated psychophysical stress on a profle of mitochondrial biogenesis markers in the hypothalamus and adenohypophysis. Rats were either lef undisturbed (freely moving, control group) or exposed to psychophysical stress by immobilization (IMO) for 2 h (acute, 1xIMO) or 2 h daily for 2 (repeated, 2xIMO) or 10 consecutive days (repeated, 10xIMO). Result suggest that all types of immobilization stress signifcantly increase expression of hypothalamic NRF1 (nuclear respiratory factor 1; acts on the genes for subunits of the OXPHOS encoded by the nuclear genome) as well as its downstream target TFAM (mitochondrial transcription factor A), the essential ubiquitous factors for mtDNA replication and expression. In the same samples, TFB1M (markedly enhance mtDNA transcription) significantly decreased, while the level of COX4 (mitochondrial complex IV cytochrome C oxidase) protein was reduced only in hypothalamuses isolated from repeatedly stressed rats. Independently of the type of stress, the level of PGC1 protein, the master regulator of mitochondrial biogenesis involved in transcriptional control of all processes related to mitochondrial homeostasis and integrator of environmental signals, remained unchanged. In adenohypophyses of the same animals, 10xIMO signifcantly increased expression of adenohypophyseal PGC1 as well as its downstream target TFB1M, while NRF1 and TFAM remained unchanged. Similarly to hypothalamuses, the level of COX4 protein was reduced in adenohypophyses isolated from repeatedly stressed rats. Our results provide new molecular insights into the relationship between stress and hypothalamo-adenohypophyseal axis, as well as mitochondrial biology