Impact des champs électriques pulsés à courte durée d'impulsion/pause sur le colmatage des membranes en cours de procédés électromembranaires: mécanismes d'action et influence sur les performances des procédés

L’approvisionnement en eau potable fraîche, en aliments sains, en substances bioactives et en énergie peut être accompli par une technologie verte comme l’électrodialyse (ED). Actuellement, deux obstacles majeurs entravent l’utilisation d’une telle technologie par l’industrie, soit les phénomènes de colmatage membranaire et la polarisation de la concentration (CP). Les travaux récents ont démontré que l’application d’un champ électrique pulsé (CEP) pendant l’ED peut éliminer complètement le colmatage par les protéines et peut diminuer considérablement le colmatage par les minéraux. De plus, les impulsions de courant préviennent l’élargissement de la couche de CP. Malgré des résultats prometteurs d’application du CEP, la durée optimale des impulsions/pauses et l’influence du CEP sur le colmatage membranaire et la CP dans des solutions contenant les agents d’encrassement sont encore des questions ouvertes et discutables. Les résultats de la thèse montrent que les champs électriques pulsés avec des durées d’impulsion/pause courtes peuvent être appliqués pour éliminer complètement le colmatage minéral sur les membranes échangeuses d’anions et pour contrôler le colmatage minéral sur le membranes échangeuses de cations au cours des procédés électromembranaires. De plus, l’application de courants surlimites provoquant la formation de vortex électroconvectifs a des avantages en matière de diminution du colmatage et d’amélioration de la performance des procédés. Il est démontré pour la première fois dans cette thèse qu’il est possible d’appliquer un champ électrique pulsé sur des cellule d’électrodialyse comprenant dans leur configuration membranaire une ou plusieurs membrane(s) bipolaire(s). Finalement, des traitements électromembranaires efficaces de solutions contenant des protéines peuvent être effectués par couplage avec des membranes d’ultrafiltration: ce couplage permet d’éviter la formation de colmatage protéique au sein de la cellule d’ED.Supply of fresh drinking water, healthy food, bio-active substances and power may be accomplished by ecofriendly electrodialysis (ED) technology. Nowadays, two main barriers such as membrane fouling and concentration polarization (CP) phenomena stand in the way of ED processes. Recent works demonstrated that application of pulsed electric field (PEF) during ED might completely eliminate protein fouling and drastically decrease fouling by minerals (scaling). Moreover, the current pulsations prevent widening of concentration polarization layer. In spite of the promising results of PEF application, the optimal duration of pulse/pause lapses and influence of PEF on membrane fouling and CP in the solutions containing fouling agents are still opened and disputable questions. The thesis results demonstrate that PEF with short pulse/pause durations can be applied to electromembrane processes in order to avoid completely the scaling on anion-exchange membrane and to control the scaling on cation-exchange membrane. Moreover, “overlimiting” currents inducing the formation of electroconvective vortices are advantageous from the point of scaling decrease and improvement of process performance. The possible application of PEF to ED systems with bipolar membrane(s) was demonstrated for the first time. Furthermore, effective electromembrane treatments of solutions containing proteins could be performed with pretreatment by ultrafiltration membrane, which avoids the clogging of ED stack

Mississippi Valley Type ore deposits, the Laisvall Pb-Zn deposit and origin of Pb-Zn-bearing sandstone glacial erratic from the Raahe area

Abstract. The Geological Survey of Finland collected zinc-, lead- and copper-bearing glacial sandstone boulders in 1970’s and 1980’s south of Raahe, Finland. The origin of these sandstones remains inconclusive. The petrographic analysis shows sphalerite, galena, pyrite and chalcopyrite as the main ore-bearing minerals in the matrix of the sedimentary rocks, associated with quartz, feldspar and calcite. Signs of a carbonate-cemented sediment and metal-rich fluid interaction suggest that mineralization was formed as part of a Mississippi Valley type deposit system. The main hypotheses suggest that the boulders were derived from the Laisvall MVT deposit of Sweden or from an unknown mineralization in the Bothnia Bay. The objective of this study was to make a literature review of the Laisvall deposit and analyze the compositional range of sphalerite in a sample from Raahe and compare it to the chemical characteristics of the Laisvall MVT deposit in Norwegian Caledonides, to determine the origin of Raahe glacial erratic sample. The second objective of the study was to assess the dependency of the color on the iron content of the sphalerite. The study is completed by optical microscopy and electron microprobe analysis (EPMA)

EVOLUTION OF THE CONCEPT AND INSTRUMENTS OF DEOFFSHORIZATION OF THE RUSSIAN ECONOMY

Offshore zones were widely used in the Russian economic practice that has led to contradictions between interests of business and the state. In the article tools and the directions of deoffshorization of the Russian economy at the present stage are considered and generalized

EVOLUTION OF THE CONCEPT AND INSTRUMENTS OF DEOFFSHORIZATION OF THE RUSSIAN ECONOMY

Offshore zones were widely used in the Russian economic practice that has led to contradictions between interests of business and the state. In the article tools and the directions of deoffshorization of the Russian economy at the present stage are considered and generalized

Milk protein production by a more environmentally sustainable process : bipolar membrane electrodialysis coupled with ultrafiltration

The increased demand for food production to nourish the rapidly growing human population raises serious sustainability issues for the food sector. Indeed, conventional food production lines involve processes having a significant environmental burden. Hence, the present study aims to demonstrate an environmentally sustainable process of food production. The milk protein was chosen as a model food ingredient due to its exceptional role in the human diet. The proposed innovative process of milk protein production includes bipolar membrane electrodialysis coupled with ultrafiltration (EDBM-UF). The crucial problem during the EDBM-UF of milk, such as different types of membrane fouling, was successfully solved. Moreover, the life cycle assessment of the novel EDBM-UF protein production process was carried out and compared to a conventional acid/base process. Additionally, a sensitivity test of electricity supply at different geographical locations of the world was performed since electricity is the main energy source for the EDBM-UF process and it could be derived from different sources (renewable and non-renewable). The assessment results demonstrate that the proposed electromembrane process has significant environmental benefits compared to the conventional process using chemicals independently from the electricity supply mix from all considered geographical locations. Thus, EDBM-UF could become a prospective industrial technology taking into account environmental concerns and promoting the development of healthy human society

Теоретическое исследование активационных барьеров элементарных реакций ступенчатого дегидрирования молекулы тетрааланата титана

Theoretical calculations of the potential energy surfaces along the minimum energy pathway have been performed for elementary step-wise dehydration reactions of Ti tetrahydroaluminate by using the density functional (B3LYP) and coupled cluster (CCSD(T)) methods with the 6-311++G** basis set.В рамках метода функционала плотности (B3LYP) и метода связанных кластеров (ССSD(T)) с базисом 6-311++G** выполнены расчеты поверхностей потенциальной энергии вдоль минимальных энергетических путей для элементарных реакций последовательного отрыва молекулярного водорода от тетрааланата титана

Теоретическое исследование элементарных реакций дегидрирования амминоборатных и амминоаланатных комплексов магния

Theoretical calculations of the potential energy surfaces along the minimum energy pathway have been performed for elementary step-wise dehydration reactions of ammine magnesium borohydride and alumohydride complexes Mg(MH4)2(NH3)2 and their dimers [Mg(MH4)2(NH3)2]2 (M = В и Al) by using the density functional (B3LYP) and coupled cluster (CCSD(T)) methods with the 6-311++G** basis set.В рамках метода функционала плотности (B3LYP) и метода связанных кластеров (ССSD(T)) с базисом 6-311++G** выполнены расчеты поверхностей потенциальной энергии вдоль минимальных энергетических путей для элементарных реакций отрыва молекул водорода от комплексных молекул амминоборатов и амминоаланатов магния Mg(MH4)2(NH3)2 и их димеров [Mg(MH4)2(NH3)2]2 (M = В и Al)

ПОСТАНОВКА И РЕШЕНИЕ ЗАДАЧИ ОПЕРАТИВНОЙ КОРРЕКЦИИ ПОТОКОВ ПРИЛЕТА И ВЫЛЕТА ВОЗДУШНЫХ СУДОВ В РАЙОНЕ АЭРОДРОМА С ПОМОЩЬЮ ГЕНЕТИЧЕСКОГО АЛГОРИТМА

The improvement in the effectiveness of airfield operation largely depends on the problem solving quality on the interaction boundaries of different technological sections. One of such hotspots is the use of the same runway by inbound and outbound aircraft. At certain intensity of outbound and inbound air traffic flow the conflict of aircraft interests appears, where it may be quite difficult to sort out priorities even for experienced controllers, in consequence of which mistakes in decision-making unavoidably appear.In this work the task of response correction of landing and takeoff time of the aircraft using the same RW, in condition of the conflict of interests “arrival – departure” at the increased operating intensity is formulated. The choice of optimal solution is made taking into account mutual interests without the complete sorting and the evaluation of all solutions.Accordingly, the genetic algorithm, which offers a simple and effective approach to optimal control problem solution by providing flight safety at an acceptably high level, is proposed. The estimation of additional aviation fuel consumption is used as optimal choice evaluation criterion.The advantages of the genetic algorithm application at decision-making in comparison with today’s “team” solution of the conflict “departure – arrival” in the airfield area are shown.Повышение эффективности работы аэродрома в значительной степени зависит от качества решения проблем на границах взаимодействия различных технологических участков, в том числе использование одной взлетно-посадочной полосы (ВПП) прилетающими и вылетающими воздушными судами (ВС). При определенной интенсивности вылетающего и прилетающего потоков движения воздушных судов неизбежно возникает конфликт их интересов, где расставить приоритеты зачастую бывает сложно даже для опытных диспетчеров, вследствие чего возникают ошибки при принятии решения.В данной работе сформулирована задача оперативной коррекции времени посадки и взлета воздушных судов, использующих одну ВПП в условиях возникновения конфликта интересов «прилет-вылет» при повышенной операционной интенсивности. Выбор варианта оптимального решения производится с учетом обоюдных интересов без полного перебора и оценки всех вариантов решения.В этой связи предложен генетический алгоритм, предлагающий простой и эффективный подход к решению задачи выбора оптимального управления при обеспечении безопасности полетов на приемлемо высоком уровне. В качестве критериев оценки оптимальности выбора используется оценка дополнительного расхода авиационного топлива.Показаны преимущества применения генетического алгоритма при выборе решения по сравнению с принятым сегодня «командным» вариантом разрешения конфликта вылета и прилета в районе аэродрома

Теоретическое исследование активационных барьеров элементарных реакций ступенчатого дегидрирования молекул комплексных алюмо-гидридов легких металлов

Theoretical calculations of the potential energy surfaces along the minimum energy pathway have been performed for elementary step-wise dehydration reactions of molecules and ions of light-metal hydroaluminates (Li, Na, K, Mg, Ca and Zn) by using the density functional (B3LYP) and coupled cluster (CCSD(T)) methods with the 6-311++G** basis set.В рамках метода функционала плотности (B3LYP) и метода связанных кластеров (ССSD(T)) с базисом 6-311++G** выполнены расчеты поверхностей потенциальной энергии вдоль мини-мальных энергетических путей для элементарных реакций последовательного отрыва моле-кулярного водорода от комплексных молекул аланатов легких металлов (Li, Na, K, Mg, Ca и Zn)